ANATOMY, ■ 
DESCRIPTIVE AND SURGICAL. 
BY 
HENRY GRAY, F. R. S., 
Fellow of the Royal College of Surgeons; Lecturer on Anatomy at St. George's 
Hospital Medical School. 
THE DRAWINGS BY H. V. CARTER, M.D., 
Late Demonstrator of Anatomy at St. George's Hospital. 
WITH ADDITIONAL DRAWINGS IN LATER EDITIONS. 
/ 
EDITED BY 
T. PICKERING PICK, 
Surgeon to, and Lecturer on Surgery at, St. George's Hospital ; Senior Surgeon, Victoria 
Hospital for Children ; Member of the Court of Examiners, 
Royal College of Surgeons of England. 
A NEW AMERICAN FROM THE ELEVENTH ENGLISH EDITION. 
THOROUGHLY REVISED AND RE-EDITED WITH ADDITIONS 
By WILLIAM W. KEEN, M. D., 
Professor of Surgery in the Jefferson Medical College of Pennsylvania; Professor of Artistic 
Anatomy in the Pennsylvania Academy of the Fine Arts ; formerly Professor of Surgery 
in the Woman's Medical College of Pennsylvania, and Lecturer on Anatomy in 
the Philadelphia School of Anatomy ; Surgeon to St. Agnes' Hospital ; 
Fellow of the College of Physicians of Philadelphia, etc. 
TO WHICH IS ADDED 
LANDMARKS, MEDICAL AND SURGICAL. 
By LUTHER HOLDEN, F.R.C.S. 
WITH ADDITIONS BY WILLIAM W. KEEN, M.D. 
PHILADELPHIA: 
LEA BROTHERS & CO. 
1 887. Entered, according to the Act of Congress, in the year 1887 by 
LEA BROTHERS & CO., 
In the Office of the Librarian of Congress. All rights reserved. 
Westcott & Thomson, 
Slereotypers and Electrotypers, Philada. 
William J. Dornan, 
Printer, Philada. TO 
SIR BENJAMIN COLLINS BRODIE, BART., 
F.R.S., D.C.L., 
SERJEANT-SURGEON TO THE QUEEN, 
CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE, 
t f 
$4jis is 
IN ADMIRATION OF 
HIS GREAT TALENTS 
AND IN REMEMBRANCE OF 
Many acts of kindness shown to the author 
FROM AN 
EARLY PERIOD OF HIS PROFESSIONAL CAREER. PREFACE TO THE NEW AMERICAN EDITION. 
At the request of the American Publishers I have subjected the new English 
edition of Gray's Anatomy to a careful revision, and have superintended its passage 
through the press. At first sight it would seem almost a work of supererogation 
to attempt even a criticism of a book which has carried on its title-page the names 
of some of the most distinguished English anatomists; yet I trust that my labors 
will prove not unfruitful. 
In addition to the correction of minor and obvious typographical errors in the 
English sheets, and many similar corrections in the cuts, the whole of Gray's master- 
piece has received a more methodical arrangement, and many cross-references both 
to text and cuts have been inserted for the convenience of the student. The text 
has been unaltered, except in two portions. At my request, Prof. John A. Ryder 
of the University of Pennsylvania revised the section on Development. A good 
many small but important changes he found necessary in the text, and in some 
instances paragraphs were rewritten as footnotes. His own personal views on many 
of the details of Embryology will be more accurately and more fully expressed in a 
work on that subject which he is now preparing. 
In the section on the Brain I rejected the English cuts showing the sulci and 
convolutions, and substituted the more accurate and generally-adopted plates of 
Ecker. The text was correspondingly inaccurate, and could not be adapted to the 
new illustrations without a few changes, which it is hoped will facilitate the study 
of this difficult part of anatomy. I have also carefully described the Cerebral Circu- 
lation, and have added a section on Cerebral Localization and Topography-subjects 
of great and increasing importance, especially in view of the recent rapid strides in 
Cerebral Surgery. The chief anatomical text-book in the English language ought 
not, I think, to be behind in this department, but should lend its aid to further 
progress by giving the fullest and most accurate knowledge attainable. Among 
the other additions to the text may be noted also paragraphs on the action of the 
muscles of the foot-sole; a more accurate description of the Pectoralis major, 
Supinator longus, and Thenar muscles; and a careful description of the palmar 
fascia. 
In all, one hundred and thirteen new engravings have been added, of which many 
are original. These, with their descriptive matter, and likewise all my other addi- 
4 PREFA CE. 
5 
tions, have been distinguished by brackets. Among these new illustrations are many 
of the most obvious utility, such as a series of sections through important joints ; a 
series of frozen sections through the trunk, the extremities, and the female pelvis; 
cuts illustrating the histology of various tissues; the shoulder and pelvic girdles; 
the interior of the nose and the larynx ; the development and occlusion of the teeth 
and the absorption of the alveolar processes ; the structure of the muscles ; the liga- 
mentum nuchse ; the Occipito-frontal and Interosseous muscles ; the palmar fascia ; 
a series giving the points for the application of electricity to the muscles; a series 
on the circulation of the brain and spinal cord; another series to illustrate cerebral 
localization and topography; another on the cutaneous distribution of the nerves; 
a number of cuts to elucidate the anatomy of the cerebrum ; two showing the sym- 
pathetic nerve; and others illustrating the peritoneum, the muscularis mucosae, the 
female perineum, and the genito-urinary organs of both sexes. Wherever practicable, 
colors have been introduced to distinguish the veins, arteries, and nerves, so that 
in the colored edition the American additions shall be in harmony with this novel 
feature of the latest English original. There is scarcely a section of the work, 
therefore, which has not been extensively enriched in the matter of illustrations. 
The text has been prefaced with a paper " On the Systematic Use of the 
Living Model in Teaching Anatomy,' and in the section on the Muscles those 
postures, resisted motions, and athletic exercises have been noted which I have 
found in teaching to be best adapted for showing the form and action of individual 
muscles. The additional interest thus infused into the subject will lead the student 
to use his own person as an ever-present living model-a habit possessing the 
greatest possible usefulness. My experience in lecturing before the Pennsylvania 
Academy of the Fine Arts has convinced me also of the great advantages to be 
derived by teachers as well as students from a thorough study of the masterpieces 
of sculpture, which are generally available at least in large cities. Among the most 
valuable for this purpose may be mentioned the Fighting Gladiator, the Dying 
Gladiator, the Wrestlers, the Ilyssus, the Theseus, the Laocoon, Angelo's Night 
and Morning, Milo of Crotona, the Venus de Milo, the Torso, the Farnese Hercules, 
the Antinoiis,. and others. Additional instruction may be obtained by the use of 
the electric current, which furnishes a convenient means of demonstrating the 
action of individual muscles or of groups of muscles. Plates have been inserted 
to facilitate the use of this method of investigation. 
I have again revised Holden's well-known Landmarks, and made still further 
additions, all of which are indicated by brackets. 
WILLIAM W. KEEN. 
1729 Chestnut Street, Philadelphia,) 
October 1, 1887. I PREFACE TO THE ELEVENTH EDITION. 
In this edition considerable alterations have been made. The Introduction of 
former editions has been incorporated in. the body of the work, for the most part in 
the form of two sections-one on General Anatomy, the other on Development. 
These have been entirely rewritten, in order to keep pace with the ever-increasing 
activity of research in these branches of the science of Anatomy. Some portions of 
the Introduction have, however, been removed from their former position and intro- 
duced in their appropriate places in other parts of the work ; as, for instance, the 
minute structure of the spinal cord, which has been inserted, with the general 
description of this part, in the section devoted to the Nervous System. 
The whole of the work has undergone a careful revision; many clerical errors 
and errors in point of detail have been corrected. In the section on Osteology an 
endeavor has been made to give more accurately the time for the appearance of the 
several centres of ossification of the bones, though this is a point on which anatomists 
differ, and which probably varies in different cases. In the section on Arthrology 
the movement or movements permitted in each joint have been carefully revised, 
and the muscles by which these movements are effected have been given. In the 
section on Myology the action of each muscle or group of muscles has been carefully 
considered, and many alterations and corrections made. The anomalous muscles 
mentioned in former editions have been excluded. It was thought that, interesting 
as these anomalous conditions may be to the scientific anatomist, they were scarcely 
necessary, and were to a certain extent out of place in a textbook intended for the 
use of the student of Anatomy. The other parts of the work, and especially that 
devoted to Microscopic Anatomy, have been carefully revised, and some alterations 
in arrangement and detail have been introduced. 
The whole of the arteries, veins, and nerves in the woodcuts have been colored, 
and it is hoped that this will give additional clearness to the illustrations and enhance 
the value of the work.1 In the section on Osteology the dotted lines showing the 
attachment of the muscles have also been colored. These have all been done in one 
color, and not, as is the practice in some works of Anatomy, in two colors, the one 
showing the so-called "origin," and the other the "insertion" of the muscle. It 
was felt that, as the origin and insertion are absolutely fixed in only a very small 
number of muscles, and that the greater number can be made to act from either 
extremity, this practice was misleading to the student, and caused him to attach 
too great importance to one action of a muscle which it might possess over any 
other. 
The Editor is deeply indebted to many friends for their assistance in the prepara- 
tion of this edition. Especially are his warmest thanks due to Mr. Ross, Demonstrator 
of Anatomy at St. George's Hospital, not only for many valuable hints and sugges- 
tions, and for the time and trouble he has devoted to investigating several subjects 
on which there appeared to be a difference of opinion amongst anatomists, but also 
for the assistance he has rendered in passing the pages through the press. To Dr. 
Ddldpine, Lecturer on Physiology at St. George's Hospital, and to Mr. B. T. 
Lowne, Lecturer on Physiology at the Middlesex Hospital, his best thanks are due 
for their kindness in revising the sections on General Anatomy and Development 
respectively. 
The Editor's pupils, Mr. Codd, Mr. Le Cronier Lancaster, and Mr. Barton, have 
also rendered him valuable assistance in the work. 
[i The American edition is published both with and without colors.] 
6 CONTENTS. 
PAGE 
On the Systematic Use of the Living Model as a Means of Illustration in Teaching 
Anatomy 33 
General Anatomy. 
PAGE 
The Blood 35 
The Lymph and Chyle 39 
The Animal Cell 40 
Epithelium 42 
Connective Tissues 45 
Pigment ..... 50 
Cartilage 50 
Fibro-cartilage 52 I 
Yellow or Reticular Cartilage .'.... 53 I 
Bone 54 
Development of Bone 59 
Muscular Tissue 64 
Unstriped Muscle 67 
Nervous Tissue 68 
The Brain 72 
The Nerves 72 
The Sympathetic Nerves 74 ; 
PAGE 
Terminations of Nerves ....... 74 
The Ganglia 77 
The Vascular System 78 
The Arteries 78 
The Capillaries 81 
The Veins 83 
The Lymphatics . 84 
The Lymphatic Glands 87 
The Skin and its Appendages 89 
The Nails 92 
The Hair 92 
The Sebaceous Glands 94 
The Sudoriferous Glands 94 
Serous Membranes 95 
Synovial Membranes 96 
Mucous Membranes 96 
Secreting Glands 97 
Development. 
Growth and Development of the Body ... 99 
The Ovum 99 
Fecundation of 101 
Segmentation of 101 
Division of Blastodermic Membrane .... 102 
First Rudiments of the Embryo 103 
The Amnion 109 
The Chorion 110 
The Allantois Ill 
The Decidua Ill 
The Placenta . . . 113 
Development of the Embryo proper .... 113 
The Spine 113 
The Cranium and Face 115 
The Nervous Centres 118 
The Nerves 120 
The Eye 121 
The Ear .122 
The Nose- 123 
The Skin, Glands, and Soft Parts .... 123 
The Limbs and Muscles 124 
The Blood-vascular System 124 
The Vitelline Circulation 124 
The Placental Circulation 126 
The Veins 128 
The Alimentary Canal and its Appendages . 130 
The Respiratory Organs 132 
The Urinary Organs 132 
The Generative Organs 135 
Male Organs 135 
Female Organs 135 
External Organs 137 
Chronological Table of the Development of 
the Foetus 139 
DESCRIPTIVE AND SURGICAL ANATOMY. 
Osteology. 
The Skeleton 141 
Number and Form of the Bones 141 
The Spine. 
General Characters of a Vertebra 143 
Characters of the Cervical Vertebrae .... 143 
Atlas 144 
Axis 145 
Vertebra Prominens 147 
Characters of the Dorsal Vertebrae . . . . 147 
Peculiar Dorsal Vertebrae 149 
Characters of the Lumbar Vertebrae .... 149 
Structure of the Vertebrae 150 
Development of the Vertebrae 150 
" Atlas 151 
" Axis 152 
" Seventh Cervical .... 152 
" Lumbar Vertebrae . . . 152 
Progress of Ossification in the Spine .... 152 
Sacrum 152 
Coccyx 157 
Of the Spine in general 158 
The Skull. 
Bones of the Cranium 160 
Occipital Bone 160 
Parietal Bones 164 
Frontal Bone 166 
Temporal Bones 170 
Sphenoid Bone 176 
Ethmoid Bone 181 
Development of the Cranium 183 
The Fontanelles 184 
Wormian Bones 184 
Congenital Fissures and Gaps 184 
Bones of the Face: 
Nasal Bones 185 
Superior Maxillary Bones 186 
7 8 
CONTENTS. 
PAGE 
Bones of the Face: 
Lachrymal Bones . . 191 
Malar Bones 192 
Palate Bones 193 
Inferior Turbinated Bones 196 
Vomer 197 
Lower Jaw 197 
Changes produced in Lower Jaw by Age . 200 
Sutures of the Skull 202 
Vertex of the Skull 204 
Base of the Skull, Internal Surface 205 
Anterior Fossa 206 
Middle Fossa 206 
Posterior Fossa 207 
Base of Skull, External Surface 208 
Lateral Region of the Skull 211 
Temporal Fossa 211 
Zygomatic Fossa 212 
Spheno-maxillary Fossa 212 
Anterior Region of the Skull 213 
Orbits 214 
Nasal Fossae 215 
Hyoid Bone 219 
The Thorax. 
The Sternum 220 
The Ribs 224 
Peculiar Ribs 226 
Costal Cartilages 228 
The Upper Extremity. 
The Shoulder ... 229 
The Clavicle ..... 229 
The Scapula 233 
The Humerus 237 
The Forearm ..... 242 
The Ulna 243 
The Radius 248 
PAGE 
The Hand 250 
The Carpus 250 
Bones of the Upper Row 250 
Bones of the Lower Row 252 
The Metacarpus 255 
Peculiar Characters of the Metacarpal Bones. 256 
Phalanges 257 
Development of the Bones of the Hand . . . 259 
The Lower Extremity. 
Os Innominatum 260 
Ilium 261 
Ischium 261 
Pubes 261 
Development of the Os Innominatum .... 266 
The Pelvis 267 
Differences between the Male and Female 
Pelvis 270 
The Femur 270 
The Leg 276 
Patella , . 277 
Tibia 278 
Fibula 281 
The Foot 284 
Tarsus 284 
Os Calcis 284 
Cuboid 287 
Astragalus 288 
Scaphoid 289 
Internal Cuneiform 289 
Middle Cuneiform 290 
External Cuneiform 290 
Metatarsal Bones 291 
Phalanges . . 292 
Development of the Bones of the Foot '. . . 294 
Sesamoid Bones 294 
The Articulations. 
Structures composing the Joints 296 
Articular Lamella of Bone 296 
Ligaments 296 
Synovial Membrane 296 
Bursae 297 
Synovia 297 
Forms of Articulation: 
Synarthrosis 297 
Amphiarthrosis 298 
Diarthrosis 298 
Movements of Joints 300 
Articulations of the Trunk. 
Articulations of the Vertebral Column . . . 301 
" " Atlas with the Axis . . 306 
" " Spine with the Cranium. 309 
" " Atlas with the Occipital 
Bone 309 
" " Axis with the Occipital 
Bone 309 
Temporo-maxillary Articulation 310 
Articulations of the Ribs with the Vertebrae: 
Costo-vertebral . . 313 
Costo-transverse 314 
Articulations of the Cartilages of the Ribs 
with the Sternum and Ensiform Carti- 
lage 315 
Interchondral Articulations 317 
Ligaments of the Sternum 317 
Articulation of the Pelvis with the Spine . . 318 
" Sacrum and Ilium . . . 319 
Ligament between the Sacrum and Ischium . 320 
Articulation of the Sacrum and Coccyx . . . 320 
" " Pubes 321 
Articulations of the Upper Extremity. 
Sterno-clavicular 322 
Scapulo-clavicular 324 
Proper Ligaments of the Scapula 326 
Shoulder-joint 326 
Elbow-joint 329 
Radio-ulnar Articulations 332 
Wrist-joint 335 
Articulations of the Carpus 336 
Carpo-pietacarpal Articulations 338 
Metacarpo-phalangeal Articulations 340 
Articulations of the Phalanges 341 
Articulations of the Lower Extremity. 
Hip-joint 342 
Knee-joint 346 
Articulations between the Tibia and Fibula . 353 
Ankle-joint 354 
Articulations of the Tarsus 357 
Tarso-metatarsal Articulations 360 
Articulations of the Metatarsal Bones .... 361 
Metatarso-phalangeal Articulations 361 
Articulations of the Phalanges . 361 
Muscles and Fasciae. 
General Description of Muscle 362 
" " Tendons ...... 364 
" Aponeuroses .... 364 
" " Fascia 364 
Muscles and Fasciae of the Cranium and 
Face. 
Subdivision into Groups 365 
Cranial Region. 
Dissection . . , 366 
Occipito-frontalis 366 
Auricular Region. 
Dissection 369 
Attollens Aurem: Attrahens Aurem 369 
Retrahens Aurem : Actions 369 CONTENTS. 
9 
PAGE 
Palpebral Region. 
Dissection369 
Orbicularis Palpebrarum370 
Corrugator Supercilii370 
Tensor Tarsi: Actions371 
Orbital Region. 
Dissection371 
Levator Palpebrae371 
Rectus Superior, Inferior, Internal and Ex- 
ternal Recti371 
Superior Oblique372 
Inferior Oblique373 
Actions : Surgical Anatomy373 
Nasal Region. 
Pyramidalis Nasi374 
Levator Labii Superioris Alaeque Nasi .... 374 
Dilatator Naris, Anterior and Posterior . . . 374 
Compressor Nasi374 
Narium Minor374 
Depressor Alae Nasi: Actions374 
Superior Maxillary Region. 
Levator Labii Superioris (Proprius)375 
Levator Anguli Oris375 
Zygomatici: Actions375 
Inferior Maxillary Region. 
Dissection376 
Levator Labii Inferioris376 
Depressor Labii Inferioris376 
Depressor Anguli Oris376 
Intermaxillary Region. 
Dissection377 
Orbicularis Oris377 
Buccinator377 
Risorius 378 
Actions378 
Temporo-maxillary Region. 
Masseter378 
Temporal Fascia379 
Dissection379 
Temporal379 
Pterygo-maxillary Region. 
Dissection380 
External Pterygoid380 
Internal Pterygoid381 
Actions 381 
Muscles and Fasci.-e of the Neck. 
Subdivision into Groups381 
Superficial Region. 
Dissection 382 
Superficial Cervical Fascia382 
Platysma Myoides382 
Deep Cervical Fascia383 
Sterno-mastoid 385 
Boundaries of the Triangles of the Neck . . 385 
Actions385 
Surgical Anatomy386 
Infrahyoid Region. 
Dissection 386 
Sterno-hyoid386 
Sterno-thyroid . . 386 
Thyro-hyoid387 
Omo-hyoid337 
Actions388 
Suprahyoid Region. 
Dissection'388 
Digastric 388 
Stylo-hyoid388 
Mylo-hyoid389 
Genio-hyoid389 
Actions'389 
PAGE 
Lingual Region. 
Dissection 389 
Genio-hyo-glossus390 
Hyo-glossus390 
Lingualis and Intrinsic Fibres of Tongue . . 391 
Stylo-glossus . 392 
Palato-glossus392 
Actions392 
Pharyngeal Region. 
Dissection392 
Inferior Constrictor392 
Middle Constrictor, Superior Constrictor . . 393 
Stylo-pharyngeus394 
Actions394 
Palatal Region. 
Dissection394 
Levator Palati394 
Tensor Palati394 
Azygos Uvulae395 
Palato-glossus396 
Palato-pharyngeus396 
Actions396 
Surgical Anatomy396 
Vertebral Region (Anterior'). 
Rectus Capitis Anticus Major397 
Rectus Capitis Anticus Minor397 
Rectus Lateralis, Longus Colli398 
Vertebral Region (Lateral). 
Scalenus Anticus, Scalenus Medius398 
Scalenus Posticus398 
Actions399 
Muscles and Fasciae of the Trunk. 
Subdivision into Groups399 
Muscles of the Back. 
Subdivision into Layers399 
First Layer. 
Dissection399 
Trapezius,499 
Ligamentum Nuchce491 
Latissimus Dorsi494 
Second Layer. 
Dissection493 
Levator Anguli Scapulae493 
Rbomboideus Minor and Major493 
Actions493 
Third Layer. 
Dissection 
Serratus Posticus Superior and Inferior . . . 404 
Vertebral Aponeurosis 405 
Splenius Capitis and Colli405 
Actions495 
Fourth Layer. 
Dissection 499 
Erector Spinae499 
Sacro-lumbalis499 
Musculus Accessorius ad Sacro-lumbalem . . 409 
Cervicalis Ascendens409 
Longissimus Dorsi499 
Transversalis Colli499 
Trachelo-mastoid 
Spinalis Dorsi 
Spinalis Colli493 
Complexus, Biventer Cervicis498 
Fifth Layer. 
Dissection 
Semispinalis Dorsi and Colli499 
Multifidus Spinae' 499 
Rotatores Spinae499 
Supraspinales • 449 
Interspinales449 10 
CONTENTS. 
PAGE 
Extensor Coccygis 410 
Intertransversales 410 
Rectus Capitis Posticus Major and Minor . . 410 
Obliquus Inferior 410 
Obliquus Superior 411 
Actions 411 
Muscles of the Abdomen. 
Dissection 412 
Obliquus Externus 412 
Obliquus Interims 414 
Transversal is 415 
Lumbar Fascia 416 
Rectus 417 
Pyramidalis, Quadratus Lumborum 418 
Linea Alba 418 
Line® Semilunares, Line® Transvers® . . . 419 
Actions 419 
Muscles and Fasciae of the Thorax. 
Intercostal Fasciae 420 
External and Internal Intercostals ..... 420 
Infracostales, Triangularis Sterni 420 
Levatores Costarum 421 
Actions 421 
Diaphragmatic Region. 
Diaphragm 422 
Actions 425 
Muscles and Fascije of the Upper Extremity. 
Subdivision into Groups 425 
Dissection of Pectoral Region and Axilla . . 426 
Fasciae of the Thorax 426 
Anterior Thoracic Region. 
Pectoral is Major 427 
Costo-coracoid Membrane 429 
Pectoralis Minor 429 
Subclavius 429 
Actions 429 
Lateral Thoracic Region. 
Serratus Magnus 430 
Actions 430 
Acromial Region. 
Deltoid 432 
Actions 432 
Anterior Scapular Region. 
Subscapular Fascia 433 
Subscapularis: Actions 433 
Posterior Scapular Region. 
Dissection 433 
Supraspinous Fascia 433 
Supraspinatus 433 
Infraspinous Fascia 433 
Infraspinatus 434 
Teres Minor 434 
Teres Major 435 
Actions 435 
Anterior Humeral Region. 
Deep Fascia of Arm 435 
Coraco-brachialis 436 
Biceps 436 
Brachialis Anticus 437 
Actions 437 
Posterior Humeral Region. 
Triceps 438 
Subanconeus : Actions 438 
Muscles of Forearm. 
Deep Fascia of Forearm 439 
Anterior Brachial Region, Superficial Layer. 
Pronator Radii Teres 440 
Flexor Carpi Radialis 440 
Palmaris Longus 441 
Flexor Carpi Ulnaris 441 
Flexor Digitorum Sublimis 441 
PAGE 
Anterior Brachial Region, Deep Layer. 
Flexor Profundus Digitorum 442 
Flexor Longus Pollicis 442 
Pronator Quadratus 443 
Actions 444 
Radial Region. 
Dissection 444 
Supinator Longus 444 
Extensor Carpi Radialis Longior 445 
Extensor Carpi Radialis Brevior 445 
Posterior Brachial Region, Superficial Layer. 
Extensor Communis Digitorum 446 
Extensor Minimi Digiti 446 
Extensor Carpi Ulnaris 446 
Anconeus 447 
Posterior Brachial Region, Deep Layer. 
Supinator Brevis 447 
Extensor Ossis Metacarpi Pollicis 447 
Extensor Primi Interuodii Pollicis 447 
Extensor Secundi Internodii Pollicis .... 448 
Extensor Indicis . . . 446 
Actions 449 
Muscles and Fasciee of the Hand. 
Dissection 449 
Anterior Annular Ligament 449 
Posterior Annular Ligament 450 
Palmar Fascia 450 
Muscles of the Hand. 
Radial Region 452 
Ulnar Region 454 
Middle Palmar Region 455. 
Actions 457 
Surgical Anatomy of the Muscles of the Upper 
Extremity. 
Fractures of the Clavicle 457 
" Acromion Process 456 
" Coracoid Process 458 
" Humerus 453. 
" Ulna 459 
" Olecranon 459 
" Radius 459 
Muscles and Fascije of the Lower 
Extremity. 
Subdivision into Groups 461 
Iliac Region. 
Dissection 452 
Iliac Fascia 452 
Psoas Magnus 463 
Psoas Parvus 453 
Iliacus 
Actions 465 
Anterior Femoral Region. 
Dissection 465 
Fascite of the Thigh : Superficial Fascia . . i 465 
Deep Fascia (Fascia 
Lata) 465 
Saphenous Opening . . 466 
Iliac and Pubic Por- 
tions of Fascia Lata . 466 
Tensor Vagin® Femoris .... 466 
Sartorius 
Quadriceps Extensor, Crureus 467 
Rectus Femoris 467 
Vastus Externus 468 
Vastus Interims and Crureus 468 
Subcrureus: Actions ' ' 469 
Internal Femoral Region. 
Dissection .... 4-.Q 
Gracilis 4-Q 
Pectineus .... 
Adductor Longus ' 4--Q 
Adductor Brevis ' CONTENTS. 
11 
PAGE 
Adductor Magnus 471 
Actions 472 
Gluteal Region. 
Dissection 472 
Gluteus Maximus 473 
Gluteus Medius 474 
Gluteus Minimus 474 
Pyriformis 475 
Obturator Membrane 475 
Obturator Internus 475 
Gemelli 476 
Quadratus Femoris 476 
Obturator Externus 476 
Actions 477 
Posterior Femoral Region. 
Dissection 477 
Biceps 477 
Semitendiuosus, Semimembranosus 478 
Actions 478 
Surgical Anatomy of Hamstring Tendons . . 479 
Muscles and Fascias of the Leg. 
Dissection of Front of Leg 479 
Deep Fascia of the Leg 479 
Muscles of the Leg 479 
Anterior Tibio-fibular Region. 
Tibialis Anticus 479 
Extensor Proprius Pollicis 480 
Extensor Longus Digitorum 480 
Peroneus Tertius : Actions 481 
Posterior Tibio-fibular Region, Superficial Layer. 
Dissection 481 
Gastrocnemius 482 
Soleus 483 
Tendo Achillis, Plantaris 483 
Actions 484 
PAGE 
Posterior Tibio-fibular Region, Deep Layer. 
Deep Transverse Fascia of Leg 484 
Popliteus 484 
Flexor Longus Pollicis 484 
Flexor Longus Digitorum, Tibialis Posticus . 485 
Actions 486 
Fibular Region. 
Peroneus Longus 486 
Peroneus Brevis 486 
Actions 487 
Surgical Anatomy of Tendons around Ankle. 487 
Muscles and Fasciae of the Foot. 
Anterior Annular Ligament 487 
Internal Annular Ligament 488 
External Annular Ligament 488 
Plantar Fascia 488 
Muscles of the Foot, Dorsal Region. 
Extensor Brevis Digitorum 489 
Plantar Region. 
Subdivision into Groups 489 
Subdivision into Layers 489 
First Layer 489 
Second Layer 491 
Third Layer 492 
Fourth Layer 493 
Surgical Anatomy of the Muscles of the Lower 
Extremity. 
Fracture of the Neck of the Femur 494 
" " Femur below Trochanter Mi- 
nor 494 
" " Femur above the Condyles . 495 
" " Patella 495 
" " Tibia 495 
" " Fibula, with Dislocation of 
the Foot outward 495 
[The Action of Individual Muscles, as 
shown by Electricity 496] 
The Arteries. 
General Anatomy. 
Subdivision into Pulmonary and Systemic . 501 
Distribution of-Where found 501 
Mode of Division-Anastomoses 501 
Pulmonary Artery 5C2 
Arch of the Aorta. 
Dissection 503 
Ascending Part of Arch 504 
Transverse Part of Arch 504 
Descend i hg Part of Arch 505 
Peculiarities, Surgical Anatomy 506 
Branches 507 
Peculiarities of Branches 507 
Coronary Arteries 507 
Arteria Innominata. 
Relations 508 
Peculiarities 508 
Surgical Anatomy 509 
Common Carotid Arteries. 
Course and Relations 510 
Peculiarities, Surgical Anatomy 510 
External Carotid Artery. 
Course 512 
Relations 514 
Surgical Anatomy 514 
Branches 514 
Superior Thyroid Artery. 
Course and Relations 514 
Branches 514 
Surgical Anatomy 515 
Lingual Artery. 
Course and Relations 515 
Branches 515 
Surgical Anatomy 516 
Facial Artery. 
Course and Relations 516 
Branches 517 
Peculiarities 519 
Surgical Anatomy 519 
Occipital Artery. 
Course and Relations 519 
Branches 519 
Posterior Auricular Artery 520 
Ascending Pharyngeal Artery 520 
Temporal Artery. 
Course and Relations 521 
Branches 521 
Surgical Anatomy 521 
Internal Maxillary Artery. 
Course 521 
Relations 522 
Peculiarities 522 
Branches from First Portion 523 
" " Second Portion 523 
" " Third Portion 524 
Surgical Anatomy of the Triangles of the 
Neck. 
Anterior Triangular Space. 
Inferior Carotid Triangle 525 12 
CONTENTS. 
PAGE 
Superior Carotid Triangle 526 
Submaxillary Triangle 526 
Posterior Triangular Space. 
Occipital Triangle 527 
Subclavian Triangle 527 
Internal Carotid Artery. 
Cervical Portion 528 
Petrous Portion 528 
Cavernous Portion 528 
Cerebral Portion 529 
Peculiarities, Surgical Anatomy 530 
Branches 530 
Ophthalmic Artery 530 
Cerebral Branches of Internal Carotid . . 533 
[Blood-vessels of the Brain.] 
[Carotid and Vertebral Set 534 
Ganglionic Arterial System 536 
Cortical Arterial System 537 
Anterior Cerebral 537 
Middle Cerebral or Sylvian 537 
Posterior Cerebral 538 
Nutrient Branches 539J 
Arteries of the Upper Extremity. 
Subclavian Arteries. 
First Part of Right Subclavian Artery . . . 542 
First Part of Left Subclavian Artery .... 543 
Second Part of Subclavian Artery 543 
Third Part of Subclavian Artery 544 
Peculiarities 544 
Surgical Anatomy 544 
Branches 546 
Vertebral Artery and its Branches . . . 546 
Basilar Artery and its Branches .... 549 
Cerebellar Branches of Vertebral .... 549 
Circle of Willis 550 
Thyroid Axis 550 
Inferior Thyroid 550 
Suprascapular Artery 550 
Transversalis Colli 551 
Internal Mammary 551 
Superior Intercostal 552 
Deep Cervical Artery 552 
Surgical Anatomy of the Axilla . . 553 
Axillary Artery. 
First Portion 554 
Second Portion 554 
Third Portion 555 
Peculiarities, Surgical Anatomy 555 
Branches 556 
Brachial Artery. 
Relations 559 
Bend of the Elbow 559 
Peculiarities of Brachial Artery 559 
Surgical Anatomy 560 
Branches 561 
Radial Artery. 
Relations 562 
Deep Palmar Arch 563 
Peculiarities 563 
Surgical Anatomy 563 
Branches 564 
Ulnar Artery. 
Relations 566 
Superficial Palmar Arch 566 
Peculiarities of Ulnar Artery 567 
Surgical Anatomy 567 
Branches 567 
Descending Aorta 569 
Thoracic Aorta. 
Course and Relations 570 
Surgical Anatomy .' 570 
Branches . 570 
PAGE 
Abdominal Aorta. 
Course 571 
Relations 573 
Surgical Anatomy 573 
Branches 574 
Coeliac Axis, Gastric Artery 574 
Hepatic Artery 574 
Splenic Artery 576 
Superior Mesenteric Artery 577 
Inferior Mesenteric Artery 579 
Suprarenal Arteries 580 
Renal Arteries 580 
Spermatic Arteries . 581 
Phrenic Arteries 581 
Lumbar Arteries 581 
Middle Sacral Artery 582 
Common Iliac Arteries. 
Course and Relations 582 
Peculiarities, Surgical Anatomy 583 
Internal Iliac Artery. 
Course and Relations 584 
Peculiarities 585 
Surgical Anatomy . . . . 585 
Branches 586 
Vesical Arteries 586 
Hemorrhoidal Arteries 586 
Uterine and Vaginal Arteries 586 
Obturator Artery 587 
Internal Pudic Artery 588 
Sciatic Artery 590 
Ilio-lumbar Artery 591 
Lateral Sacral Artery ... 591 
Gluteal Artery 591 
External Iliac Artery. 
Course 591 
Relations 592 
Surgical Anatomy 592 
Deep Epigastric Artery 593 
Deep Circumflex Iliac Artery 593 
Femoral Artery. 
Course and Relations 594 
Scarpa's Triangle 594 
Peculiarities of the Femoral Artery .... 596 
Surgical Anatomy 596 
Branches 597 
Profunda Artery and its Branches 598 
Popliteal Artery. 
Course and Relations 599 
Popliteal Space 600 
Peculiarities 601 
Surgical Anatomy 601 
Branches 603 
Anterior Tibial Artery. 
Course and Relations 603 
Peculiarities, Surgical Anatomy 603 
Branches 605 
Dorsalis Pedis Artery. 
Course and Relations 605 
Peculiarities, Surgical Anatomy 606 
Branches 606 
Posterior Tibial Artery. 
Course and Relations 607 
Peculiarities, Surgical Anatomy 607 
Branches 608 
Peroneal Artery. 
Course and Relations 608 
Peculiarities 609 
Plantar Arteries 610 CONTENTS. 
13 
The Veins. 
PAGE 
General Anatomy. 
Subdivision into Pulmonary, Systemic, and 
Portal 611 
Anastomoses of Veins 611 
Superficial Veins, Deep Veins, Venae Comites. 611 
Sinuses 612 
Pulmonary Veins 612 
Veins of the Head and Neck. 
Facial Vein ... 613 
Temporal Vein 614 
Internal Maxillary Vein 614 
Temporo-maxillary Vein 614 
Posterior Auricular Vein, Occipital Vein . . 615 
Veins of the Neck. 
External Jugular Vein 615 
Posterior External Jugular Vein 615 
Anterior Jugular Vein 615 
Internal Jugular Vein 616 
Lingual and Pharyngeal 616 
Thyroid Veins, Vertebral Veins ...... 616 
Veins of the Diploe 617 
Cerebral Veins. 
Superficial Cerebral Veins 618 
Deep Cerebral Veins 618 
Cerebellar Veins 619 
Sinuses of the Dura Mater. 
Superior Longitudinal Sinus 619 
Inferior Longitudinal, Straight 620 
Lateral and Occipital Sinuses 620 
Cavernous Sinuses 621 
Circular Petrosal 621 
Inferior Petrosal 622 
Transverse Sinuses 622 
Superior Petrosal Sinus 622 
PAGE 
Veins of the Upper Extremity. 
Superficial Veins 623 
Deep Veins 623 
Axillary Vein 625 
Subclavian Vein 625 
Innominate Veins 625 
Peculiarities of 626 
Internal Mammary Veins 626 
Inferior Thyroid Veins 626 
Superior Intercostal Veins 627 
Superior Vena Cava 627 
Azygos Veins 627 
Bronchial Veins 628 
Spinal Veins 628 
Veins of the Lower Extremity. 
Internal Saphenous Vein 630 
External Saphenous Vein 631 
Popliteal Vein 631 
Femoral Vein 631 
External Iliac Vein 631 
Internal Iliac Vein . 631 
Common Iliac Veins 632 
Inferior Vena Cava 633 
Peculiarities 633 
Lumbar and Spermatic Veins 633 
Ovarian and Renal Veins 631 
Suprarenal Veins 631 
Phrenic Veins 634 
Hepatic Veins 634 
Portal System of Veins. 
Inferior Mesenteric Vein 634 
Superior Mesenteric Vein 634 
Splenic Vein 635 
Gastric Veins 635 
Portal Vein 636 
Cardiac Veins 636 
Coronary Sinus 637 
The Lymphatics. 
General Anatomy. 
Subdivision into Deep and Superficial .... 638 
Lymphatic or Conglobate Glands 638 
Thoracic Duct 639 
Right Lymphatic Duct 640 
Lymphatics of Head, Face, and Neck. 
Superficial Lymphatic Glands of Head . . . 640 
" Lymphatics of the Head 640 
of the Face 641 
Deep Lymphatics of the Face 641 
of the Cranium 641 
Superficial Cervical Glands 642 
Deep Cervical Glands 642 
Superficial and Deep Cervical Lymphatics . . 642 
Lymphatics of the Upper Extremity. 
Superficial Lymphatic Glands 643 
Deep Lymphatic Glands 643 
Axillary Glands .... 643 
Superficial Lymphatics of Upper Extremity . 644 
Deep Lymphatics of Upper Extremity . . . 644 
Lymphatics of the Lower Extremity. 
Superficial Inguinal Glands 644 
Deep Lymphatic Glands 645 
Anterior Tibial Gland 645 
Deep Popliteal Glands 645 
Deep Inguinal Glands 645 
Gluteal and Ischiatic Glands 645 
Superficial Lymphatics of Lower Extremity. 645 
Internal Group 645 
External Group 646 
Deep Lymphatics of Lower Extremity . . . 646 
Lymphatics of Pelvis and Abdomen. 
Deep Lymphatic Glands of Pelvis 646 
External Iliac Glands 646 
Internal Iliac Glands 646 
Sacral Glands 646 
Lumbar Glands 646 
Superficial Lymphatics of Wall of Abdomen . 646 
Superficial Lymphatics of Gluteal Region . . 647 
of Scrotum and Peri- 
neum 647 
" of Penis 647 
" of Labia, Nymphse, 
and Clitoris .... 648 
Deep Lymphatics of Pelvis and Abdomen . . 648 
Lymphatics of Bladder 648 
of Rectum 648 
of Uterus 648 
of Testicle 648 
" of Kidney . . . . 648 
of Liver 648 
Lymphatic Glands of Stomach 649 
Lymphatics of Stomach 649 
Lymphatic Glands of Spleen 649 
Lymphatics of Spleen . 649 
Lymphatic System of the Intestines. 
Lymphatic Glands of Small Intestine (Mes- 
enteric Glands) 649 
Lymphatic Glands of Large Intestine .... 649 
Lymphatics of Small Intestine (Lacteals) . . 649 
of Large Intestine 649 
Lymphatics of Thorax. 
Deep Lymphatic Glands of Thorax 649 
" Intercostal Glands 649 14 
CONTENTS. 
PAGE 
Deep Internal Mammary Glands 650 
" Anterior Mediastinal Glands 650 
" Posterior Mediastinal Glands 650 
Superficial Lymphatics on Front of Thorax 650 
Deep Lymphatics of Thorax 650 
" Intercostal Lymphatics 650 
" Internal Mammary Lymphatics .... 650 
PAGE 
Lymphatics of Diaphragm 650 
Bronchial Glands 650 
Lymphatics of Lung 650 
Cardiac Lymphatics 650 
Thymic Lymphatics 651 
Thyroid Lymphatics 651 
Lymphatics of GEsophagus 651 
Nervous System 
General Anatomy. 
Subdivision into Cerebro-spinal Axis, Gan- 
glia, and Nerves 652 
The Spinal Cord and its Membranes. 
Dissection 652 
Membranes of the Cord 652 
Dura Mater 652 
Arachnoid 653 
Pi a Ma ter 654 
Ligamentum Denticulatum 654 
Spinal Cord 654 
Fissures of Cord 655 
Columns of Cord 655 
Structure of the Cord 656 
Minute Anatomy of the Cord 656 
Neuroglia 656 
White Substance 657 
Gray Substance 658 
Origin of the Spinal Nerves in the Cord . . . 660 
Central Canal of the Cord 661 
The Brain and its Membranes. 
Membranes of the Brain 661 
Dura Mater. 
Structure 661 
Arteries, Veins, Nerves 662 
Glandulse Pacchioni 662 
Processes of the Dura Mater 662 
Falx Cerebri 662 
Tentorium Cerebelli 663 
Falx Cerebelli 663 
Arachnoid Membrane. 
Subarachnoid Space 663 
Cerebro-spinal Fluid 664 
Pia Mater 664 
THE BRAIN. 
Subdivision into Cerebrum, Cerebellum, Pons 
Varolii, Medulla Oblongata 664 
Weight of Brain 665 
Medulla Oblongata. 
Anterior Pyramids 666 
Lateral Tract and Olivary Body 666 
Restiform Bodies 666 
Posterior Pyramids 666 
Posterior Surface of Medulla Oblongata . . . 667 
Structure of Medulla Oblongata 667 
" of Anterior Pyramid 667 
" of Lateral Tract 667 
" of Olivary Body 667 
" of Restiform Body 668 
Septum of Medulla Oblongata 668 
Gray Matter of Medulla Oblongata 668 
Pons Varolii. 
Structure 670 
Transverse Fibres 670 
Longitudinal Fibres 672 
Septum 672 
Cerebrum. 
Upper Surface of Cerebrum 672 
Convolutions 672 
Sulci 673 
Fissure of Sylvius 675 
Sulci: Fissure, of Rolando 675 
Parieto-occipital Fissure 675 
Lobes: 
Frontal Lobe 676 
Parietal Lobe . . . 676 
Occipital Lobe 677 
Temporo-sphenoidal Lobe 677 
Central Lobe [Insula] 677 
Calloso-marginal Fissure 678 
Parieto-occipital Fissure 678 
Calcarine Fissure 678 
Collateral Fissure 679 
Dentate Fissure 679 
Gyrus Fornicatus 679 
Marginal Convolution 679 
Quadrate Lobe 680 
Cuneate Lobe 680 
Uncinate Gyrus 680 
Temporo-sphenoidal Lobe 680 
[Cerebral Localization and Topography . . . 681] 
[Motor Centres . 681 
Landmarks on the Skull 684 
Bony Points 684 
Sutures 684 
Relation of Fissures and Convolutions to 
Landmarks on the Skull 685 
Fissure of Rolando 685 
Fissure of Sylvius * 686 
Precentral Sulcus 686 
Inferior Frontal Sulcus 686 
Superior Frontal Sulcus 686 
Intraparietal Sulcus 686 
Parieto-occipital Fissure 6871 
Base of the Brain 687 
General Arrangement of the Parts composing 
the Cerebrum 690 
Interior of the Cerebrum 690 
Corpus Callosum 691 
Lateral Ventricles 692 
Corpus Striatum 693 
Tsenia Semicircularis 694 
Choroid Plexus 694 
Corpus Fimbriatum 695 
Hippocampus 696 
Transverse Fissure 697 
Septum Lucidum 697 
Fifth Ventricle 697 
Fornix 698 
Velum Interpositum 699 
Thalamus Opticus 699 
Third Ventricle . . . 700 
Commissures of Third Ventricle . . 700 
Foramen of Monro 702 
Pineal Gland 702 
Corpora Quadrigemina 702 
Valve of Vieussens 703 
Corpora Geniculata . 703 
Internal Structure of Cerebrum 703 
Gray Matter of the Cortex 703 
" Basal Ganglia 705 
Central Gray Matter of the Cerebrum .... 706 
White Matter of the Cerebrum 706 
Diverging Fibres 706 
Commissural Fibres 707 
Cerebellum. 
Its Position, Size, Weight, etc 708 
Cerebellum, Upper Surface 70S 
" Under Surface . 709 CONTENTS. 
15 
PAGE 
Lobes of the Cerebellum 710 
Internal Structure of the Cerebellum .... 710 
White Matter of Cerebellum 711 
Peduncles of Cerebellum 711 
PAGE 
Gray Matter of Cerebellum ' 711 
Fourth Ventricle 712 
Lining Membrane 714 
Choroid Plexuses -714 
Cranial Nerves. 
Subdivision into Groups 715 
Olfactory Nerve 716 
Optic Nerve 717 
" Tracts . 717 
" Commissure 717 
Motor Oculi Nerve 718 
Pathetic Nerve 719 
Trifacial Nerve 719 
Gasserian Ganglion 720 
Ophthalmic Nerve 720 
Lachrymal, Frontal, and Nasal Branches. 721 
Ophthalmic Ganglion 722 
Superior Maxillary Nerve 723 
Spheno-palatine Ganglion 725 
Inferior Maxillary Nerve 727 
Auriculo-temporal Branch 728 
Gustatory Branch 729 
Inferior Dental Branch 729 
Otic Ganglion 729 
Submaxillary Ganglion 730 
Abducens Nerve 731 
Relations of the Orbital Nerves: 
in the Cavernous Sinus 732 
in the Sphenoidal Fissure 732 
in the Orbit 732 
Facial Nerve 732 
Branches of Facial Nerve 734 
Auditory Nerve 736 
Glosso-pharyngeal Nerve 736 
Pneumogastric (Vagus) Nerve 738 
Spinal Accessory Nerve 741 
Hypoglossal Nerve 742 
Spinal Nerves. 
Roots of the Spinal Nerves 744 
Origin of Anterior Roots 744 
" of Posterior Roots 744 
Ganglia of the Spinal Nerves 745 
[Divisions of the Spinal Nerves.] 
Anterior Divisions of the Spinal Nerves . . . 745 
Posterior Divisions of the Spinal Nerves . . 745 
[Points of Origin and Emergence of the 
Spinal Nerves 745] 
Cervical Nerves. 
Roots of the Cervical Nerves 746 
Posterior Divisions of the Cervical Nerves . 747 
Anterior Divisions of the Cervical Nerves . . 749 
Cervical Plexus. 
Superficial Branches of the Cervical Plexus . 750 
Deep Branches of the Cervical Plexus .... 751 
Brachial Plexus. 
Branches above the Clavicle : 
Posterior Thoracic, Suprascapular .... 754 
Branches below the Clavicle : 
Anterior Thoracic 755 
Subscapular Nerves 755 
Circumflex Nerve 756 
Musculo-cutaneous Nerve 756 
Internal Cutaneous Nerve 756 
Lesser Internal Cutaneous Nerve .... 757 
Median Nerve 759 
Ulnar Nerve 761 
Musculo-spiral Nerve 762 
Radial Nerve 763 
Posterior Interosseous Nerve 764 
Dorsal Nerves. 
Roots of the Dorsal Nerves 764 
Posterior Divisions of the Dorsal Nerves . . 764 
Anterior Divisions of the Dorsal Nerves . . 764 
First Dorsal Nerve 766 
Intercostal Nerves 766 
Upper Dorsal Nerves 766 
Intercosto-liumeral Nerve 766 
Lower Dorsal Nerves 766 
Last Dorsal Nerve 767 
Lumbar Nerves. 
Loot of Lumbar Nerves 767 
Posterior Divisions of Lumbar Nerves . . . 767 
Anterior Divisions of Lumbar Nerves .... 767 
Lumbar Plexus. 
Branches of Lumbar Plexus 768 
Uio-hypogastric Nerve 769 
Ilio-inguinal and Genito-crural Nerves . . . 770 
External Cutaneous Nerve 770 
Obturator Nerve 770 
Accessory Obturator Nerve 773 
Anterior Crural Nerve 773 
Branches of Anterior Crural 773 
Middle Cutaneous 773 
Internal Cutaneous 773 
Long Saphenous 774 
Muscular and Articular Branches .... 774 
Sacral and Coccygeal Nerves. 
Roots of, Origin of 775 
Posterior Sacral Nerves 775 
Coccygeal Nerve 775 
Anterior Sacral Nerves 775 
Sacral Plexus. 
Superior Gluteal Nerve 778 
Pudic Nerve 778 
Small Sciatic Nerve 778 
Great Sciatic Nerve 780 
Internal Popliteal Nerve 780 
Short Saphenous Nerve 781 
Posterior Tibial Nerve 781 
Plantar Nerves 781 
External Popliteal or Peroneal Nerve .... 782 
Anterior Tibial Nerve 782 
Musculo-cutaneous Nerve 783 
Subdivision of, into Parts . . . 784 
Branches of the Ganglia, General Description 
of ' 784 
Cervical Portion of the Gangliated Cord . . 787 
Superior Cervical Ganglion 787 
Carotid and Cavernous Plexuses 789 
Sympathetic Nerve. 
Middle Cervical Ganglion 790 
Inferior Cervical Ganglion 791 
Thoracic Part of the Gangliated Cord .... 791 
Great Splanchnic Nerve 791 
Lesser Splanchnic Nerve 791 
Smallest Splanchnic Nerve 791 16 
CONTENTS. 
PAGE 
Lumbar Portion of the Gangliated Cord . . . 792 
Pelvic Portion of the Gangliated Cord . . . 792 
The Great Plexuses of the Sympathetic. 
The Cardiac Plexuses 792 
The Great Cardiac Plexus 792 
The Superficial Cardiac Plexus 793 
The Coronary Plexuses 793 
The Solar Plexus . 793 
The Phrenic Plexus 794 
The Suprarenal Plexus 794 
The Renal Plexus 794 
PAGE 
The Spermatic Plexus . 794 
The Coeliac Plexus 794 
The Superior Mesenteric Plexus 796 
The Aortic Plexus 796 
The Inferior Mesenteric Plexus . 796 
The Hypogastric Plexus 796 
The Pelvic Plexus 796 
The Inferior Hemorrhoidal Plexus 796 
The Vesical Plexus 796 
Prostatic Plexus 796 
Vaginal Plexus .... 797 
Uterine Plexus 797 
Organs of Sense. 
Tongue. 
Papillae of 800 
Glands of 800 
Fibrous Septum of 801 
Arteries and Nerves of 801 
Nose. 
Cartilages of 802 
Muscles of 803 
Skin 803 
Mucous Membrane 803 
Arteries, Veins, and Nerves 803 
Nasal Fossse. 
Mucous Membrane of 803 
Peculiarities of, in Superior, Middle, and 
Inferior Meatuses 804 
Arteries, Veins, and Nerves of Nasal Fossae . 804 
Eye. 
Situation, Form of 805 
Tunics of 806 
Sclerotic . . . . • 806 
Cornea 807 
Choroid 809 
Ciliary Processes 810 
Iris 810 
Membrana Pupillaris 812 
Ciliary Muscle 812 
Retina 812 
Structure of Retina 813 
" " at Yellow Spot 816 
Arteria Centralis Retinae 816 
Humors o f the Eye. 
Aqueous Humor 816 
Anterior Chamber 816 
Posterior Chamber 816 
Vitreous Body 817 
Crystalline Lens and its Capsule 817 
Changes Produced in the Lens by Age . . . 818 
Suspensory Ligament of Lens 818 
Canal of Petit 818 
Vessels of the Globe of the Eye 819 
Nerves of Eyeball 819 
Appendages of the Eye. 
Eyebrows 819 
Eyelids 819 
Structure of the Eyelids 819 
Tarsal Cartilages 820 
Meibomian Glands 820 
Eyelashes 821 
Conjunctiva 821 
Carunculae Lachrymales 821 
Lachrymal Apparatus. 
Lachrymal Gland 821 
" Canals 822 
" Sac 822 
Nasal Duct 822 
Ear. 
Pinna, or Auricle 823 
Structure of the Pinna 823 
Ligaments of the Pinna 823 
Muscles of the Pinna 824 
Arteries, Veins, and Nerves of the Pinna . . 824 
Auditory Canal 825 
Middle Ear, or Tympanum. 
Cavity of Tympanum 826 
Eustachian Tube 828 
Membrana Tympani 829 
Structure of 829 
Ossicles of the Tympanum . . • 829 
Ligaments of the Ossicula 830 
Muscles of the Tympanum 830 
Mucous Membrane of Tympanum 831 
Arteries of Tympanum 831 
Veins and Nerves of Tympanum 831 
Internal Ear, or Labyrinth. 
Vestibule 832 
Semicircular Canals: 
Superior Semicircular Canal 833 
Posterior Semicircular Canal 833 
External Semicircular Canal 833 
Cochlea: 
Central Axis of, or Modiolus 833 
Spiral Canal of 833 
Scala Tympani, Scala Vestibuli, and Scala 
Media 834 
The Organ of Corti 835 
Perilymph 837 
Membranous Labyrinth 837 
Utricle and Saccule 837 
Membranous Semicircular Canals 837 
Endolymph 838 
Otoliths 838 
Vessels of the Labyrinth 838 
Auditory Nerve, Vestibular Nerve 838 
Cochlear Nerve 838 
VISCERA. 
Organs of Digestion and their Appendages. 
Subdivisions of the Alimentary Canal.... 839 
The Mouth 839 
The Lips 839 
The Cheeks 840 
The Gums 840 
Teeth. 
General Characters of 840 
Permanent Teeth 841 
Incisors and Canine - . . 841 
Bicuspids, Molars 841 CONTENTS. 
17 
PAGE 
Temporary or Milk Teeth 843 
Structure of the Teeth 843 
Ivory or Dentine 844 
Enamel 845 
Cortical Substance 845 
Development of the Temporary Teeth . . . 846 
" " Permanent Teeth . . . 848 
Eruption of the Teeth 849 
Palate. 
Hard Palate 850 
Soft Palate 850 
Uvula, Pillars of the Soft Palate 851 
Mucous Membrane, Aponeurosis, and Muscles 
of Soft Palate 851 
Tonsils. 
Arteries 851 
Veins and Nerves of Tonsils 852 
Salivary Glands. 
Parotid Gland. 
Stenson's Duct 853 
Vessels and Nerves of Parotid Gland .... 853 
Submaxillary Gland. 
Wharton's Duct 853 
Vessels and Nerves of Submaxillary Gland . 854 
Sublingual Gland. 
Vessels and Nerves of 854 
Structure of Salivary Glands 854 
Pharynx. 
Structure of Pharynx 856 
(Esophagus. 
Relations of (Esophagus 857 
Surgical Anatomy 857 
Structure of (Esophagus 858 
Abdomen. 
Boundaries 858 
Apertures of 859 
Regions 859 
Peritoneum. 
Reflections Traced 860 
Foramen of Winslow 866 
Lesser Omentum 867 
Great Omentum 867 
Gastro-splenic Omentum 867 
Mesentery 867 
Mesocsecum 868 
Mesocolon, Mesorectum, Appendices Epi- 
ploicse 868 
Stomach. 
Situation 869 
Splenic End, Pyloric End 869 
Cardiac and Pyloric Orifices 869 
Greater and Lesser Curvatures 869 
Surfaces 870 
Ligaments of 870 
Alterations in Position 870 
Pylorus 870 
Structure of Stomach 871 
Serous and Muscular Coats 871 
Mucous Membrane 872 
Gastric Follicles 872 
Vessels and Nerves of Stomach 874 
Small Intestine. 
Duodenum 874 
Ascending Portion 874 
Descending Portion 875 
Transverse Portion 875 
Vessels and Nerves of Duodenum 876 
Jejunum 876 
Ileum 876 
Structure of Small Intestine 876 
Serous and Muscular Coats 876 
PAGE 
Mucous Membrane 877 
Epithelium and Valvulee Conniventes .... 877 
Villi-their Structure 877 
Simple Follicles 879 
Duodenal Glands 879 
Solitary Glands 880 
Agminate, or Peyer's Glands . 880 
Large Intestine. 
Csecum 882 
Appendix Cseci Vermiformis 882 
Ileo-caecal Valve 882 
Colon . . 883 
Ascending 883 
Transverse ... 883 
Descending 883 
Sigmoid Flexure 885 
Rectum 886 
Upper Portion .... 886 
Middle Portion 886 
Lower Portion 886 
Structure of Large Intestine 886 
Serous and Muscular Coats 887 
Circular and Mucous Coats 887 
Epithelium, Simple Follicles 888 
Solitary Glands 888 
Liver. 
Size, Weight, Position of 889 
Its Surfaces and Borders 889 
Changes of Position 889 
Ligaments: 
Longitudinal 889 
Lateral 890' 
Coronary 8901 
Bound Ligament 891 
Fissures: 
Longitudinal 891 
Fissure of Ductus Venosus 891 
Portal Fissure 891 
Fissures for Gall-bladder and Vena Cava. 891 
Lobes : 
Right 891 
Left 892 
Quadratus, Spigelii 892 
Caudatus 892 
Vessels of Liver 892 
Nerves of Liver 892 
Structure of Liver . ... . 892 
Serous Coat, Fibrous Coat 892 
Lobules 893 
Hepatic Cells 893 
Hepatic Artery 894 
Portal Vein 894 
Hepatic Veins 894 
Biliary Ducts 895 
Gall-bladder. 
Structure 896 
Biliary Ducts 896 
Hepatic Duct 896 
Common Choledic and Cystic Ducts . . . 896 
Structure of Biliary Ducts 897 
Pancreas. 
Dissection 897 
Relations 897 
Duct 898 
Structure . . 898 
Vessels and Nerves 899 
Spleen. 
Relations '899 
Size and Weight 899 
Structure of Serous and Fibrous Coats . . . 900 
Proper Substance 900 
Splenic Artery, distribution 901 
Malpighian Corpuscles 902 
Capillaries of Spleen 902 
Veins of Spleen 903 
Lymphatics and Nerves . 903 18 
CONTENTS. 
Thorax. 
PAGE 
Boundaries of 904 
Superior Opening, Base 904 
Parts passing through Upper Opening .... 904 
Pericardium. 
Structure 904 
Fibrous Layer 905 
Serous Layer 905 
Heart. 
Position, Size 906 
Subdivision into Four Cavities 907 
Circulation of Blood in Adult 907 
Auriculo-ventricular and Ventricular Grooves. 907 
Right Auricle. 
Openings .. . . . 908 
Valves 908 
Relics of Foetal Structure 909 
Musculi Pectinati 909 
Right Ventricle. 
Openings 909 
Tricuspid Valve 909 
page 
Chordae Tendinese and Columnse Carnese . . 910 
Semilunar 910 
Left Auricle. 
Sinus, Appendix 911 
Openings, Musculi Pectinati 911 
Left Ventricle. 
Openings 912 
Mitral and Semilunar Valves 912 
Endocardium 912 
Structure of Heart. 
Fibrous Rings 913 
Muscular Structure 913 
" " of Auricles 913 
" of Ventricles 913 
Vessels and Nerves of Heart 915 
Peculiarities in Vascular System of Foetus . 915 
Foramen Ovale, Eustachian Valve 915 
Ductus Arteriosus 915 
Umbilical or Hypogastric Arteries 916 
Foetal Circulation 916 
Changes in Vascular System at Birth .... 918 
The Larynx. 
Cartilages of the Larynx ■ . . 919 
Thyroid Cartilage 919 
Cricoid 920 
Arytenoid' Cartilages 920 
Cartilages of Santorini and Wrisberg . . 921 
Epiglottis 921 
Ligaments of the Larynx 921 
Ligaments connecting the Thyroid Cartilage 
with the Os Hyoides 921 
Ligaments connecting the Thyroid Cartilage 
with the Cricoid 922 
Ligaments connecting the Arytenoid Carti- 
lages to the Cricoid 922 
Ligaments of the Epiglottis 922 
Superior Aperture of the Larynx 922 
Cavity of the Larynx 923 
Glottis 923 
False Vocal Chords 923 
True Vocal Chords 924 
Ventricle of Larynx, Sacculus Laryngis . . . 924 
Muscles of Larynx 924 
Crico-thyroid 924 
Crico-arytsenoideus posticus 924 
" " lateralis 925 
Arytsenoideus 925 
Thy ro-arytaenoi deus 925 
Muscles of the Epiglottis 926 
Thyro-epiglottideus 926 
Arytseno-epiglottideus, superior .... 926 
" " inferior 926 
Actions of Muscles of Larynx 926 
, Mucous Membrane of Larynx 927 
Glands, Vessels, and Nerves of Larynx . . . 927 
Trachea. 
Relations 927 
Bronchi 927 
Organs of Voice and Respiration. 
Structure of Trachea 929 
Surgical Anatomy of Laryngo-tracheal Re- 
gion 930 
The Pleura?. 
Reflections 931 
Vessels and Nerves 932 
Mediastina. 
Superior Mediastinum 934 
Anterior Mediastinum 934 
Middle Mediastinum 934 
Posterior Mediastinum 934 
The Lungs. 
Surfaces 934 
Borders and Lobes 935 
Root of Lung 935 
Weight, Color, and Properties of Substance 
of Lung 936 
Structure of Lung 936 
Serous Coat and Subserous Areolar Tissue . . 936 
Parenchyma and Lobules of Lung . ... . 936 
Bronchi, Arrangement of, in Substance of 
Lung 936 
Structure of Smaller Bronchial Tubes .... 937 
The Air-cells 937 
Pulmonary Artery 937 
Pulmonary Capillaries and Veins 937 
Bronchial Arteries and Veins 939 
Lymphatics and Nerves of Lung 939 
Thyroid Gland. 
Structure 940 
Vessels and Nerves 941 
Thymus Gland. 
Structure 942 
Vessels and Nerves 942 
The Urinary Organs. 
Kidneys. 
Relations 944 
Dimensions, Weight 945 
General Structure 945 
Cortical Substance 946 
Medullary Substance 946 
Minute Structure 946 
Malpighian Bodies 946 
" Tufts 946 
" Capsule 947 
Tubuli Uriniferi, Course 947 
" " Structure 948 
Renal Blood-vessels 949 
" Veins 951 CONTENTS. 
19 
PAGE 
Venae Rectae 951 
Lymphatics and Nerves 951 
Ureters. 
Situation, Calices 952 
Course, Relations, Structure 952 
Suprarenal Capsules. 
Relations, Structure 953 
Vessels 954 
Nerves 955 
The Pelvis. 
Boundaries, Contents 955 
PAGE 
Bladder. 
Shape, Position, Relations 955 
Urachus 955 
Subdivisions 956 
Ligaments 957 
Structure 957 
Interior of Bladder 958 
Vessels and Nerves 959 
Male Urethra. 
Divisions 959 
Structure 960 
Male Generative Organs. 
Prostate Glands. 
Position, Size, and Weight 962 
Structure 963 
Vessels and Nerves 963 
Cowper's Glands 963 
Penis. 
Root 964 
Glans Penis 964 
Body 964 
Corpora Cavernosa 964 
Erectile Tissue 965 
Arteries of the Penis 965 
Corpus Spongiosum 966 
The Bulb " 966 
Structure of Corpus Spongiosum 966 
Lymphatics of the Penis 966 
Nerves of the Penis 966 
The Testes and their Coverings. 
Scrotum 967 
Other Coverings of the Testis 967 
Vessels and Nerves of the Coverings of the 
Testis 968 
Spermatic Cord. 
Its Composition 968 
Relations of, in Inguinal Canal . 968 
Arteries of the Cord 968 
Veins of the Cord 968 
Lymphatics and Nerves of the Cord .... 969 
Testes. 
Form and Situation 969 
Size and Weight 969 
Coverings 969 
Tunica Vaginalis 969 
Tunica Albuginea 970 
Mediastinum Testis 970 
Tunica Vasculosa 970 
Structure of the Testis . . 970 
Lobules of the Testis . 970 
Tubuli Seminiferi 970 
Arrangement in Lobuli 970 
" in Mediastinum Testis .... 970 
in Epididymis 971 
Vas Aberrans 971 
Vas Deferens, Course, Relations 972 
Structure 972 
Vesiculae Seminales 972 
Form and Size 972 
Relations 973 
Structure 973 
Ejaculatory Ducts 973 
The Semen 973 
Descent of the Testes. 
Gubernaculum Testis 974 
Canal of Nuck 975 
Female Organs of Generation. 
Mons Veneris, Labia Majora, Labia Minora . 976 
Clitoris, Meatus Urinarius 977 
Hymen 977 
Glands of Barth oline 978 
Female Bladder 978 
" Urethra 978 
" Rectum 979 
Vagina. 
Relations 979 
Structure 979 
Uferits. 
Situation, Form, Dimensions 980 
Fundus, Body, and Cervix 981 
Ligaments 981 
Cavity of the Uterus . 981 
Structure 981 
Vessels and Nerves 983 
Its Form, Size, and Situation 983 
in the Foetus 983 
Its Form at Puberty . . 983 
" during and after Menstruation . . 983 
" during Pregnancy 983 
" after Parturition 983 
" in Old Age 983 
Appendages of the Uterus. 
Fallopian Tubes 984 
Structure 984 
Ovaries 984 
Structure 985 
Graafian Vesicles 986 
Discharge of the Ovum 987 
Corpus Luteum 987 
Ligament of the Ovary 988 
Pound Ligaments 988 
Vessels and Nerves of Appendages 988 
Mammary Glands. 
Situation and Size, Nipple . 988 
Structure of Mamma 989 
Vessels and Nerves 989 
Surgical Anatomy of Inguinal Hernia. 
Coverings of Inguinal Hernia. 
Dissection 991 
Superficial Fascia . 991 
Superficial Vessels and Nerves 991 
Deep Layer of Superficial Fascia 991 
Aponeurosis of External Oblique ...... 992 20 
CONTENTS. 
PAGE 
External Abdominal Ring 993 
Pillars of the Ring 993 
Intercolumnar Fibres 993 
" Fascia 993 
Poupart's Ligament 994 
Gimbernat's Ligament 994 
Triangular Ligament 994 
Internal Oblique Muscle 994 
Cremaster 994 
Transversalis Muscle 995 
Spermatic Canal 996 
Fascia Transversalis 996 
Internal Abdominal Ring 996 
Subserous Areolar Tissue 996 
Epigastric Artery 996 
Peritoneum 996 
[General Remarks upon Hernia. 
Openings of Herniae 997 
Peculiar Coverings of Herniae 997] 
Inguinal Hernia. 
Oblique Inguinal Hernia 998 
Course and Coverings of Oblique Hernia . . 998 
Seat of Stricture 998 
Scrotal Hernia 998 
Bubonocele 998 
Congenital Hernia 999 
Infantile Hernia 999 
Direct Inguinal Hernia. 
Course and Coverings of the Hernia .... 999 
Surgical Anatomy of Perine 
Ischio-rectal Region. 
Dissection 1010 
Boundaries 1010 
Superficial Fascia 1011 
Corrugator Cutis Ani 1011 
External Sphincter 1011 
Internal Sphincter 1011 
Ischio-rectal Fossa 1011 
Position of Parts contained in 1012 
Perineum. 
Boundaries and Extent 1012 
Superficial Layer of Superficial Fascia . . 1013 
Deep Layer of Superficial Fascia 1013 
Course taken by the Urine in Rupture of the 
Urethra 1014 
Muscles of the Perineum (Male): 
Accelerator Urinae 1014 
Erector Penis 1014 
Transversus Perinaei 1014 
Muscles of the Perineum (Female): 
Sphincter Vaginae 1015 
Erector Clitoridis . 1015 
Transversus Perinaei . . 1015 
PAGh 
Seat of Stricture . 999 
Incomplete Direct Hernia 1000 
Comparative Frequency of Oblique ami Di- 
rect Hernia 1000 
Diagnosis of Oblique and Direct Hernia . . 1000 
SURGICAL ANATOMY OF FEMORAL 
HERNIA. 
Dissection 1000 
Superficial Fascia 1000 
Cutaneous Vessels 1000 
Internal Saphenous Vein 1000 
Superficial Sympathetic Glands 1001 
Cutaneous Nerves 1001 
Deep Layer of Superficial Fascia 1001 
Cribriform Fascia 1001 
Fascia Lata 1001 
Iliac Portion 1001 
Pubic Portion 1002 
Saphenous Opening 1003 
Femoral Arch 1003 
Gimbernat's Ligament 1003 
Femoral Sheath 1003 
Deep Femoral Arch 1005 
Femoral Canal 1006 
Femoral or Crural Ring 1007 
Position of Parts around the Ring 1007 
Septum Crurale [or Femorale] 1007 
Descent of- Femoral Hernia 1008 
Coverings of Femoral Hernia 1008 
Varieties of Femoral Hernia 1008 
Seat of Stricture 1009 
im and Ischio-rectal Region. 
Deep Perineal Fascia 1015 
Anterior Layer 1016 
Posterior Layer 1016 
Parts between the Two Layers ...... 1017 
Compressor Urethrae . . " 1017 
Cowper's Glands 1017 
Pudic Vessels and Nerves 1017 
Artery of the Bulb 1017 
Levator Ani 1017 
Relations, Actions 1018 
Coccygeus 1018 
Relations, Actions 1019 
Position of Viscera at Outlet of Pelvis . . . 1019 
Prostate Gland 1019 
Parts concerned in the Operation of Lith- 
otomy . 1019 
Parts Divided in the Operation 1021 
Parts to be Avoided in the Operation . . . 1021 
Abnormal Course of Arteries in the Peri- 
neum 1021 
> 
Pelvic Fascia. 
Obturator Fascia 1022 
Recto-vesical Fascia 1022 
Surgical Anatomy of the Triangles of the Neck 525 
Surgical Anatomy of the Axilla 553 
Surgical Anatomy of the Bend of Elbow 559 
Surgical Anatomy of Scarpa's Triangle 594 
Surgical Anatomy of the Popliteal Space . ' 600 
Surgical Anatomy of the Laryngo-tracheal Region 930 CONTENTS. 
21 
LANDMARKS, MEDICAL AND SURGICAL. 
page 
The Head. 
Scalp; its Density-Arteries of Scalp-Skull- 
cap- Anterior Fontanelle - Frontal Si- 
nuses-Mastoid Process-Occipital Protu- 
berance-Posterior Inferior Angle of the 
Parietal Bone-Lines of Cerebral Sinuses 
- Middle Meningeal Artery - Thickness 
of Skull-cap-Levels of the Brain-Ear- 
Cerebral Localization and Topography . 
1026,1027 
The Face. 
Foramina for Branches of Fifth Nerve-Pul- 
ley for Superior Oblique Muscle-Lower 
Jaw-Zygoma-Seventh Nerve-Parotid 
Duct-Temporal and Facial Arteries- 
Eyelids and Eyes-Puncta Lachrymalia 
-Lachrymal Sac-Nasal Duct-Nose and 
Nasal Cavities - Lips - Mouth -Teeth- 
Throat-Antrum-Posterior Nares-Ton- 
sils-Features 1027-1031 
The Neck. 
Skin-Subcutaneous Veins-Parts in Central 
Line - Os Hyoides -Thyroid Cartilage- 
Cricoid Cartilage--Trachea-Sterno-mas- 
toid Muscle - Sterno-clavicular Joint - 
Apex of Lung in the Neck-Supraclavic- 
ular Fossa-Subclavian Artery-Phrenic 
Nerve 1031-1034 
The Chest. 
Peculiarities in the Female - Parts behind 
First Bone of Sternum-Rules for Count- 
ing the Ribs-Interval below Clavicle- 
Internal Mammary Artery - Outline of 
Heart on Chest-wall-Apex of the Heart 
-Valves of the Heart-Where to Auscult 
the Valves of the Heart-Outline of the 
Lungs - Anterior Mediastinum - Reflec- 
tion of Pleura 1034-1037 
The Back. 
Median Furrow-Spines of Vertebrae-Divis- 
ion of the Trachea-Origins of the Spinal 
Nerves-Movements of the Spine-Posi- 
tion and Motions of Scapula . . . 1037-1040 
The Abdomen. 
Abdominal Lines-Umbilicus-Parts behind 
the Linea Alba - Peritoneum - Division 
of the Aorta-Bony Prominences-Spine 
of the Ilium-Spines of the Pubes-Pou- 
part's Ligament, or Crural Arch-Abdom- 
inal Rings - Inguinal Canal - Spermatic 
Cord-Epigastric Artery-Abdominal Vis- 
cera - Liver - Gall-bladder - Stomach - 
Pylorus - Spleen - Pancreas - Kidney- 
Large Intestine-Colotomy-Small Intes- 
tine-Bladder 1041-1046 
The Perineum. 
Bony Framework-Raphe-Central Point of 
the Perineum - Triangular Ligament - 
Anus-Landmarks in the Rectum-Ure- 
PAGE 
thra-Prostate Gland-Direction of the 
Anus and that of the Rectum-Introduc- 
tion of Catheters--Urethra in the Child . 
1046-1048 
The Thigh. 
Poupart's Ligament, or Crural Arch-Furrow 
at the Bend of the Thigh-Saphenous 
Opening - Femoral Ring - Lymphatic 
Glands in the Groin-Trochanter Major 
-Nelaton's Line-Spine of the Ilium- 
Compression of Femoral Artery - Sarto- 
rius-Line of Femoral Artery . . 1048-1050 
The Buttocks. 
Bony Landmarks-Fold of the Buttock-Glu- 
teal Artery-Pudic Artery .... 1050,1051 
The Knee. 
Bony Points-Ligamentum Patella;-Prepa- 
tellar Bursa-Synovial Membrane of Knee 
- Popliteal Tendons - Popliteal Bursa- 
Popliteal Artery-Peroneal Nerve . 1051-1053 
The Leg and Ankle. 
Bony Points-Malleoli-Tendo Achillis-Ten- 
dons behind the Inner Ankle-Tendons 
behind the Outer Ankle - Tendons in 
Front of the Ankle-Popliteal Artery- 
Anterior Tibial Artery-Posterior Tibial 
Artery-Saphena Veins 1053-1055 
The Foot. 
Points of Bone-Lines of Joints-Dorsal Ar- 
tery- Bursa - Plantar Arteries-Plantar 
Fascia 1055-1056 
The Arm. 
Clavicle-Bony Points of the Shoulder-Tu- 
berosi ties - Coraco-acromial Ligament - 
Axilla-Axillary Artery - Brachial Ar- 
tery-Bend of Elbow-Cutaneous Veins- 
Landmarks of Elbow-Olecranon-Rela- 
tions of the Olecranon and Condyles- 
Bursae-Interosseous Arteries-Lymphatic 
Gland 1056-1059 
The Forearm and Wrist. 
Ulna-Radius-Carpus-Pulse-Great Carpal 
Bursa -" Tabatiere anatomique "- Ten- 
dons on the Back of the Wrist-Lines of 
Arteries 1059-1061 
The Hand. 
Furrow in Palm-Interdigital Folds-Digital 
Furrows-Palmar Arterial Arches-Digi- 
tal Arteries-Metacarpal Joint of Thumb 
-Sesamoid Bones - Subcutaneous Veins 
- Interosseous Arteries - Digital Bursae 
-Knuckles and Digital Joints . . 1061,1062 
Palpation by the Rectum1062 
Examination per Vaginam1063 
Index • 1065 LIST OF ILLUSTRATIONS. 
The illustrations, when copied from any other work, have the author's name affixed. When no such 
acknowledgment is made the drawing is to be considered original. 
General Anatomy. 
FIG. PAGE 
1. Human Blood-corpuscles Kdlliker. 36 
2. Blood-corpuscles Harley. 37 
3. Changes in Shape of Colorless Corpuscles Kirkes. 37 
[4. Isolated Plaques in Normal Blood . . Osler.] 38 
5. Blood-crystals Harley. 39 
6. Chyle from the Lymphatics do. 40 
7. Pavement Epithelium do. 43 
8. Columnar Epithelium , Kdlliker. 43 
9. Goblet-cells Klein and Noble Smith. 43 
10. Spheroidal Epithelium Harley. 44 
11. Ciliated Epithelium . . Kdlliker. 44 
12. Endothelium, with Stomata Klein. 44 
13. White Fibrous Tissue Harley. 45 
14. Connective Tissue Klein and Noble Smith. 46 
15. Tendon-cell Schafer. 46 
16. Yellow Elastic Tissue Harley. 47 
17. Connective-tissue Corpuscles Klein and Noble Smith. 47 
18. Retiform Connective Tissue 48 
19. Adipose Tissue Harley. 49 
20. Development of Fat Klein and Noble Smith. 49 
21. Pigment-cells of Retina 50 
22. Human Cartilage-cells Kdlliker. 51 
23. Costal Cartilage in Old Age Harley. 52 
24. Fibro-cartilage do. 52 
25. Yellow Cartilage do. 53 
26. Transverse Section of Bone Kdlliker. 56 
27. Transverse Section of Bone Sharpey. 56 
28. Nucleated Bone-cells Klein and Noble Smith. 57 
29. Longitudinal Section of Bone Kdlliker. 57 
[30. Fibula after Maceration in Acetic Acid Dalton.] 58 
31. Section of Bone after Removal of Earthy Portion ... Harley. 58 
32. Ossification of Foetal Cartilage Rollett. 59 
33. Ossification of Limb-bone of Cat Schafer. 60 
34. Ossification of Limb-bone of Rabbit Klein and Noble Smith. 60 
35. Transverse Section of Foetal Femur Frey. 61 
36. Ossification of Foetal Cartilage do. 61 
37. Intramembranous Ossification ' do. 63 
38. Transverse Section of Muscle Kdlliker. 64 
39. Human Muscular Fibre do. 65 
40. Structure of Muscular Fibre Todd and Bowman. 65 
41. Structure of Muscular Fibre Quain. 66 
42. Krause's Membrane Klein and Noble Smith. 66 
43. Muscular Fibres of the Heart Schweigger-Seidel. 67 
44. Non-striated Muscular Fibre Harley. 68 
45. Muscular Fibre-cells Kdlliker. 68 
46. Nerve-vesicles from Gasserian Ganglion Todd and Bowman. 69 
47. Nerve-vesicles from Brain Harley. 69 
48. Human Nerve-tubes Kdlliker. 70 
[49. Diagram of Structure of Medullated Nerve-fibre From Allen.] 70 
[50. Nerve-fibre from the Sciatic Nerve of the Rabbit do. ] 70 
51. Nerve-tubes of Eel Todd and Bowman. 71 
52. Nervous Branch from Sympathetic Frey. 71 
53. Section of Nerve Klein and Noble Smith. 73 
54. Tactile Corpuscles . . . » Kdlliker. 76 
55. Pacinian Corpuscles Todd and Bowman. 76 
56. Motorial End-plates Kiihne. 77 
57. Section through a Microscopic Ganglion Klein and Noble Smith. 78 
58. Section of Artery and Vein do. 79 
23 24 
LIST OF ILLUSTRATIONS 
FIG. PAGE 
59. Longitudinal Section of Artery and Vein . Kolliker. 80 
[60. Section of Injected Lung E. A. Schafer.] 81 
61. Longitudinal Section of Bone Kolliker. 82 
[62. Small Artery, showing Structure of its Walls Landois.] 82 
63. Capillary Vessels Frey. 82 
64. Capillary Vessels Kolliker. 83 
65. Section of Thoracic Duct do. 85 
66. Stomata of Serous Membrane Frey. 85 
[67. Origin of Lymphatics from Central Tendon of Diaphragm of the Eabbit Landois.] 86 
[68. Perivascular Lymphatics do. ] 86 
69. Section of Lymphatic Gland Frey. 87 
70. Follicle from Lymphatic Gland do. 88 
71. Medullary Structure from Lymphatic Gland do. 88 
72. Minute Structure of Lymphatic Gland 88 
73. Sectional View of the Skin and its Appendages Kolliker. 89 
74. Section of Skin 90 
[75. Epidermis detached from Derma Hirychfeld and Leveille.] 91 
76. Transverse Section of Hair-follicle Beisiadecki. 93 
77. Varieties of Secreting Glands 98 
78. Ovum of Sow Jf. Barry. 99 
79. Human Ovum Kolliker. 99 
80. Fertilization of Ovum Selenka. 100 
81. Diagram of the Division of the Yolk Kolliker. 101 
82. Vitelline Spheres VanBeneden. 102 
[83. Rabbit's Ovum after Impregnation Foster and Balfour.] 102 
84. Section of Blastoderm do. 103 
85. Diagrams of the Development of the Three Layers of the Blastodermic Membrane, trans- 
verse sections Beaunis and Bouchard. 104 
86. Similar Diagrams, antero-posterior sections do. 104 
87. Embryonic Area of Eabbit Kolliker. 106 
88. Transverse Section through Embryo Chick Foster and Balfour. 106 
89. Diagrammatic Section through Ovum . . . Quain. 107 
90. Transverse Diagrammatic Section 107 
91. Human Embryo of Four Weeks Quain. 108 
[92. Diagrammatic Section of Human Uterus, Embryo in situ Longet.] 112 
93. Transverse Section through Embryo Chick Foster and Balfour. 114 
94. Primitive Vertebral Column of Embryo Kolliker. 114 
95. Longitudinal Section of Head of Embryo do. 115 
96. Vertical Section of Head of Embryo Mihalkovics. 116 
97. Face of an Embryo Coste. 117 
98. Section of the Medulla Kolliker. 119 
99. Diagram of Development of Lens Remak. 122 
100. Diagrammatic Section through Foetal Eyeball Quain. 122 
101. Development of Blood-vessels Klein. 125 
102. Heart of Embryo, Fifth Week Baer. 125 
103. Diagram of Formation of Aortic Arches and Large Arteries Kolliker. 127 
104. Primitive Veins Dalton. 128 
105. Diagram of the Formation of the Main Systemic Veins Kolliker. 129 
106. Development of Alimentary Canal ■'.... Thompson. 130 
107. Early Form of Alimentary Canal Kolliker. 131 
108. Wolffian Body in the Asexual Stage of Embryo Farre. 134 
109. Diagram of Primitive Urogenital Organs Quain. 134 
110. Adult Ovary, Parovarium, and Fallopian Tube Farre. 136 
111. Female Genital Organs of Embryo Alfred T. Muller. 136 
112. Development of External Genital Organs Ecker. 137 
Osteology. 
113. A Cervical Vertebra ' i 144 
114. Atlas 145 
115. Axis 146 
116. Seventh Cervical Vertebra 146 
117. A Dorsal Vertebra 147 
118. Peculiar Dorsal Vertebra 148 
119. Lumbar Vertebra ' 150 
120-122. Development of a Vertebra Quain. 151 
123. Atlas do. 151 
124. Axis do. 151 
125. Lumbar Vertebra do. 151 
126. Sacrum, anterior surface 153 
127. Vertical Section of the Sacrum 154 
128. Sacrum, posterior surface 155 
129-131. Development of Sacrum Quain. 156 
132. Coccyx, anterior and posterior surfaces 157 
133. Lateral View of Spine 158 
134. Occipital Bone, outer surface k 161 
135. Occipital Bone, inner surface 162 
136. Occipital Bone, development of , Quain. 164 
137. Parietal Bone, external surface 165 
138. Parietal Bone, internal surface 166 ILLUSTRATIONS. 
25 
FIG. PAGE 
139. Frontal Bone, outer surface 167 
140. Frontal Bone, inner surface 168 
141. Frontal Bone at Birth 169 
142. Temporal Bone, outer surface 170 
[143. Section through Mastoid Cells W. W. Keen.] 172 
144. Temporal Bone, inner surface 172 
145. Temporal Bone, petrous portion 173 
146. Temporal Bone, development of Quain. 175 
147. Sphenoid Bone, superior surface 176 
148. Sphenoid Bone, anterior surface 177 
149. Sphenoid Bone, posterior surface 179 
150. Plan of the Development of Sphenoid 180 
151. Ethmoid Bone, outer surface 181 
152. Perpendicular Plate of Ethmoid, enlarged 182 
153. Ethmoid Bone, inner surface of right lateral mass, enlarged 183 
154. Skull at Birth, showing the anterior and posterior fontanelles . 184 
155. Lateral Fontanelles 184 
156. Nasal Bone, outer surface 185 
157. Nasal Bone, inner surface 185 
158. Superior Maxillary Bone, outer surface 186 
159. Superior Maxillary Bone, inner surface 188 
160. Under Surface of Hard Palate 190 
161. Development of Superior Maxillary Bone Quain. 190 
162. Lachrymal Bone, outer surface 191 
163. Malar Bone, outer surface 192 
164. Malar Bone, inner surface 192 
165. Palate Bone, internal view, enlarged 194 
166. Palate Bone, posterior view, enlarged 194 
167. Inferior Turbinated Bone, inner surface 196 
168. Inferior Turbinated Bone, outer surface 196 
169. Vomer 197 
170. Lower Jaw, outer surface 198 
171. Lower Jaw, inner surface . . . 198 
172. Side View of the Lower Jaw at Birth 201 
173. Side View of the Lower Jaw at Puberty 201 
174. Side View of the Lower Jaw in the Adult 201 
175. Side View of the Lower Jaw in Old Age 201 
[176. Absorption of Alveolar Processes M. II. Cryer.] 202 
177. Base of Skull, inner surface 205 
178. Base of Skull, outer surface . - 209 
179. Side View of the Skull 211 
180. Anterior Region of Skull 214 
181. Nasal Fossae, outer wall 216 
182. Nasal Fossae, inner wall or septum 217 
[183. Transverse Vertical Section of Nasal Fossae Hirschfeld and Leveille.] 218 
[184. Naso-pharynx, viewed from behind Zaufal.] 218 
185. Hyoid Bone, anterior surface 219 
186. Sternum and Costal Cartilages, anterior surface 221 
187. Sternum, posterior surface 221 
188-191. Development of Sternum Quain. 223 
192. A Rib 224 
193. Vertebral Extremity of a Rib 225 
194-198. Peculiar Ribs 227 
199. Left Clavicle, anterior surface 231 
200. Left Clavicle, inferior surface 231 
201. Left Scapula, anterior surface, or venter 232 
202. Left Scapula, posterior surface, or dorsum 234 
203. Plan of the Development of the Scapula 236 
204. Left Humerus, anterior surface 239 
205. Left Humerus, posterior surface 240 
206. Plan of the Development of the Humerus 242 
[207. Angles at Elbows and Knees IF. IP. Keen.] 242 
208. Bones of the Left Forearm, anterior surface 244 
209. Bones of the Left Forearm, posterior surface 246 
210. Plan of the Development of the Ulna 247 
211. Plan of the Development of the Radius 249 
212. Bones of the Left Hand, dorsal surface 251 
213. Bones of the Left Hand, palmar surface 253 
214. Plan of the Development of the Hand 258 
[215. Shoulder Girdle Henle.] 259 
[216. Pelvic Girdle do. ] 259 
217. Os Innominatum, external surface . 260 
218. Os Innominatum, internal surface 262 
219. Plan of the Development of the Os Innominatum 266 
220. Male Pelvis (adult) 267 
221. Female Pelvis (adult) 268 
222. Vertical Section of the Pelvis, with lines indicating the axes of the pelvis 269 
223. Right Femur, anterior surface 272 
224. Right Femur, posterior surface 273 
225. Diagram showing the Structure of the Neck of the Femur Ward. 275 
226. Plan of the Development of the Femur 276 
227. Right Patella, anterior surface 277 26 
ILLUSTRATIONS. 
FIG. PAGE 
228. Right Patella, posterior surface 277 
229. Tibia and Fibula, anterior surface 278 
230. Tibia and Fibula, posterior surface 279 
231. Plan of the Development of the Tibia 281 
232. Plan of the Development of the Fibula 283 
233. Bones of the Right Foot, dorsal surface 285 
234. Bones of the Right Foot, plantar surface . 286 
235. Plan of the Development of the Foot 295 
Articulations. 
236. Vertical Section of Two Vertebrae and their Ligaments, front view . 302 
237. Occipito-atloid and Atlo-axoid Ligaments, front view 306 
238. Occipito-atloid and Atlo-axoid Ligaments, posterior view 307 
239. Articulation between Odontoid Process and Atlas Arnold. 307 
240. Occipito-axoid and Atlo-axoid Ligaments 308 
241. Temporo-maxillary Articulation, external view 310 
242. Temporo-maxillary Articulation, internal view 311 
243. Temporo-maxillary Articulation, vertical section 312 
244. Costo-vertebral and Costo-transverse Articulations, anterior view 313 
245. Costo-transverse Articulation Arnold. 314 
246. Chondro-sternal, Chondro-xiphoid, and Interchondral Articulations, anterior view .... 316 
247. Articulations of Pelvis and Hip, anterior view 318 
248. Articulations of Pelvis and Hip, posterior view 319 
249. Vertical Section of the Symphysis Pubis 322 
250. Sterno-clavicular Articulation 323 
251. Shoulder-joint, Scapulo-clavicular Articulations, and proper Ligaments of Scapula .... 325 
[252. Vertical Section through Shoulder-joint, arm vertical Henle.] 327 
[253. Vertical Section through Shoulder-joint, arm horizontal do. ] 327 
254. Left Elbow-joint, showing anterior and internal ligaments 330 
255. Left Elbow-joint, showing posterior and external ligaments 331 
[256. Section through Elbow-joint, in Extension Henle.] 331 
[257. Section through Elbow-joint, in Flexion do. ] 331 
258. Ligaments of Wrist and Hand, anterior view Arnold. 334 
259. Ligaments of Wrist and Hand, posterior view do. 335 
260. Vertical Section of Wrist, showing the synovial membranes 339 
[261. Relations of Knuckles and Webs of Fingers JV. W. Keen.] 340 
262. Articulations of the Phalanges 341 
263. Left Hip-joint, laid open 342 
[264. Hip-joint, showing Y-ligament Bigelow.] 343 
265. Hip-joint, laid open from the pelvis to show the ligamentum teres put on the stretch by 
rotation of the femur outward 343 
266. Hip-joint, laid open from the pelvis to show the ligamentum teres put on the stretch by 
adduction of the femur in the flexed position . 344 
267. Muscles in Relation with Hip ......................... Barton. 345 
[268. Vertical Section through Hip-joint Henle.] 346 
269. Right Knee-joint, anterior view 348 
270. Right Knee-joint, posterior view 348 
271. Right Knee-joint, showing internal ligaments 349 
272. Head of Tibia, with semilunar cartilages, seen from above 349 
[273. Sagittal Section of Knee-joint Vole.] 350 
274. Ankle-joint: Tarsal and Tarso-metatarsal Articulations, internal view 355 
275. Ankle-joint: Tarsal and Tarso-metatarsal Articulations, external view 355 
[276. Coronal Section of Ankle and Foot Vole.] 356 
[277. Sagittal Section of Ankle and Foot do. ] 357 
278. Ligaments of Plantar Surface of the Foot 359 
279. Synovial Membranes of the Tarsus and Metatarsus Arnold. 361 
Muscles and Fasciae. 
[280. Arrangement of Muscular Fibres in Muscles Beaunis and Bouchard.'] 363 
281. Plan of Dissection of the Head, Face, and Neck 367 
282. Muscles of the Head, Face, and Neck 368 
[283. Typical Wrinkles in Forehead W. W. Keen.] 368 
[284. Frontal and Ocular Muscles Henle.] 370 
285. Muscles of the Right Orbit 372 
286. The Relative Position and Attachment of the Muscles of the Left Eyeball 372 
287. The Temporal Muscle 379 
288. The Pterygoid Muscles 380 
289. Cervical Fascia 383 
290. Muscles of the Neck and Boundaries of the Triangles 384 
291. Muscles of the Neck, anterior view Quain. 387 
292. Muscles of the Tongue, left side 390 
293. Superficial Lingualis and Intrinsic Vertical Fibres of the Tongue 394 
294. Relative Positions of Intrinsic and Extrinsic Muscles of the Tongue 394 
295. Muscles of the Pharynx, external view ' 393 
296. Muscles of the Soft Palate 395 
297. The Prevertebral Muscles Quain. 397 
298. Plan of Dissection of the Muscles of the Back 409 
[299. Ligamentum Nuchie Henle.] 401 ILLUSTRATIONS. 
27 
FIG. PAGE 
300. Muscles of the Back, first, second, and part of the third layer Quain. 402 
301. Muscles of the Back, deep layers , 407 
302. Plan of Dissection of Abdomen 412 
303. The External Oblique Muscle 413 
304. The Internal Oblique Muscle 415 
305. The Transversalis, Rectus, and Pyramidalis 416 
306. Transverse Section of Abdomen in Lumbar Region Quain. 417 
307. The Diaphragm, under surface 422 
[308. Coronal Section of Trunk Henle.] 423 
[309. Sagittal Section of Trunk do. ] 423 
310. Plan of Dissection of Upper Extremity 426 
311. Muscles of the Chest and Front of the Arm, superficial view 428 
312. Muscles of the Chest and Front of the Arm, with the boundaries of the axilla 431 
313. Muscles on the Dorsum of the Scapula and the Triceps 434 
[314. Section through Middle of Right Upper Arm Heath from Beraud.] 437 
315. Front of the Left Forearm, superficial muscles 440 
[316. Section through Middle of Right Forearm Heath from Beraud.] 443 
317. Front of the Left Forearm, deep muscles 443 
318. Posterior Surface of Forearm, superficial muscles 445 
319. Posterior Surface of Forearm, deep muscles 448 
320. Transverse Section through the Wrist, showing the annular ligaments and the canals for 
the passage of the tendons 450 
[321. Palmar Fascia, seen from above TV. IF. Keen.] 451 
[322. Palmar Fascia, seen from beneath do. ] 452 
323. Muscles of the Left Hand, palmar surface 453 
[324. Adductor Interosseous Muscle of Ring Finger of Right Hand Duchenne.] 456 
325. Dorsal Interossei of Left Hand . 456 
326. Palmar Interossei of Left Hand 456 
327. Fracture of the Middle of the Clavicle Hind. 458 
328. Fracture of the Surgical Neck of the Humerus do. 458 
329. Fracture of the Humerus above the Condyles do. 459 
330. Fracture of the Olecranon * do. 459 
331. Fracture of Shaft of the Radius do. 460 
332. Fracture of the Lower End of the Radius do. 460 
333. Plan of Dissection of Lower Extremity, front view 463 
334. Muscles of the Iliac and Anterior Femoral Regions 463 
[335. Section of Right Thigh at Apex of Scarpa's Triangle Heath.] 468 
336. Muscles of the Internal Femoral Region Quain. 471 
337. Plan of Dissection of Lower Extremity, posterior view 473 
338. Muscles of the Hip and Thigh 474 
339. Muscles of the Front of the Leg 480 
[340. Section of Right Leg in Upper Third . Heath from Beraud.] 481 
341. Muscles of the Back of the Leg, superficial layer 482 
342. Muscles of the Back of the Leg, deep layers 484 
343. Muscles of the Sole of the Foot, first layer 490 
344. Muscles of the Sole of the Foot, second layer 491 
345. Muscles of the Sole of the Foot, third layer 492 
346. Dorsal Interossei 493 
347. The Plantar Interossei 493 
348. Fracture of the Neck of the Femur within the Capsular Ligament Hind. 494 
349. Fracture of the Femur below the Trochanters do. 494 
350. Fracture of the Femur above the Condyles do. 495 
351. Fracture of the Patella ... do. 495 
352. Oblique Fracture of the Shaft of the Tibia '. . . do. 496 
353. Fracture of the Fibula, with Dislocation of the foot outward (Pott's fracture) . . . do. 496 
[354. Motor-points of Head and Neck Zicmssen.] 496 
[355. Motor-points of Trunk do. ] 497 
[356. Motor-points of Upper Outer Part of Arm do. ] 497 
[357. Motor-points of Upper Inner Part of Arm do. ] 497 
[358. Motor-points of Inner Part of Lower Arm do. ] 498 
[359. Motor-points of Outer Part of Lower Arm do. ] 498 
[360. Motor-points of Anterior Part of Upper Leg do. ] 499 
[361. Motor-points of Posterior Part of Upper Leg do. ] 499 
[362. Motor-points of Outer Part of Lower Leg and Foot do. ] 500 
[363. Motor-points of Inner Part of Lower Leg and Foot do. ] 500 
Arteries. 
364. The Arch of the Aorta and its Branches 503 
365. Flan of the Branches of the Arch of the Aorta 503 
366. Surgical Anatomy of the Arteries of the Neck 513 
367. Plan of the Branches of the External Carotid 513 
368. The Arteries of the Face and Scalp 517 
369. The Internal Maxillary Artery and its Branches 522 
370. Plan of the Branches of the Internal Maxillary Artery 522 
[371. Diagram of Triangles of Right Side of Neck W. W. Keen.] 525 
372. The Internal Carotid and Vertebral Arteries 529 
373. The Ophthalmic Artery and its Branches 531 
374. The Arteries of the Base of the Brain 533 
[375. Diagram of Vessels at Base of Cerebrum Charcot.] 535 
[376. Transverse Section of Cerebral Hemispheres, showing vessels . Durst.] 535 28 
fig. ' PAGE 
[377. Vascular Areas of Upper Surface of Cerebrum Duret.] 536 
[378. Vascular Areas of Inner Surface of Eight Hemisphere Ecker and Duret.] 537 
[379. Vascular Areas of Outer Surface of Left Hemisphere do. do. ] 538 
[380. Area of Distribution of Middle Cerebral Artery Charcot.] 539 
[381. Vascular Areas of Brain, from below . Ecker and Duret.] 540 
[382. Mode of Division of Cerebral Arteries Duret.] 541 
[383. Distribution of Arteries to Gray and White Matter do. ] 541 
384. Plan of the Branches of the Eight Subclavian Artery 546 
[385. Distribution of Blood-vessels and Ganglion-cells in Spinal Cord Young.] 547 
[386. Vascular Supply of Medulla Oblongata Ross.] 548 
387. The Scapular and Circumflex Arteries 551 
388. The Axillary Artery and its Branches 557 
389. The Surgical Anatomy of the Brachial Artery 558 
390. The Surgical Anatomy of the Eadial and Ulnar Arteries 565 
391. Ulnar and Eadial Arteries, deep view 565 
392. Arteries of the Back of the Forearm and Hand 568 
393. The Abdominal Aorta and its Branches 572 
[394. Diagram of Branches of Cceliac Axis W. W. Keen.] 574 
395. The Coeliac Axis and its Branches, the liver having been raised and the 
lesser omentum removed ... 575 
396. The Cceliac Axis and its Branches, the stomach having been raised,and the 
transverse mesocolon removed 576 
397. The Superior Mesenteric Artery and its Branches 578 
[398. Diagram of Mesenteric Arteries W. W. Kean.] 578 
399. The Inferior Mesenteric Artery and its Branches 580 
400. Arteries of the Pelvis ' ' 585 
401. Variations in Origin and Course of Obturator Artery 587 
402. The Internal Pudic Artery and its Branches in the Male 588 
403. The Arteries of the Gluteal and Posterior Femoral Eegions 590 
404. Surgical Anatomy of the Femoral Artery 594 
405. The Popliteal, Posterior Tibial, and Peroneal Arteries 604 
406. Surgical Anatomy of the Anterior Tibial and Dorsalis Pedis Arteries 604 
[407. Eelation of Parts behind Inner Malleolus Hirschfeld and Leveille.] 608 
408. The Plantar Arteries, superficial view 609 
409. The Plantar Arteries, deep view 609 
IL L US TR A TIO NS. 
Veins. 
410. Veins of the Head and Neck 613 
411. Veins of the Diploe, as displayed by the removal of the outer table of the skull Breschet. 617 
412. Vertical Section of the Skull, showing the sinuses of the dura mater 619 
413. Plan showing Eelation of Structures in Cavernous Sinus 621 
414. The Sinuses at the Base of the Skull 621 
415. Eelation of Structure passing through the Jugular Foramen 622 
416. The Superficial Veins of the Upper Extremity 623 
417. The Verne Cavse and Azygos Veins, with their formative branches 626 
418. Transverse Section of a Dorsal Vertebra, showing the spinal veins Breschet. 628 
419. Vertical Section of Two Dorsal Vertebrae, showing the spinal veins do. 629 
420. The Internal or Long Saphenous Vein and its Branches 630 
421. The External or Short Saphenous Vein 630 
422. The Portal Vein and its Branches Quain. 635 
Lymphatics. 
423. The Thoracic and Eight Lymphatic Ducts 640 
424. The Superficial Lymphatics and Glands of the Head, Face, and Neck Mascagni. 641 
425. The Deep Lymphatics and Glands of the Neck and Thorax do. 642 
426. The Superficial Lymphatics and Glands of the Upper Extremity do. 643 
427. The Superficial Lymphatics and Glands of the Lower Extremity do. 645 
428. The Deep Lymphatic Vessels and Glands of the Abdomen and Pelvis do. 647 
Nervous System. 
429. The Spinal Cord and its Membranes 653 
430. Transverse Section of the Spinal Cord and its Membranes Arnold. 653 
431. Spinal Cord, side view: plan of the fissures and columns Quain. 655 
432. Transverse Sections of the Cord Arnold. 656 
433. Transverse Section of the Spinal Cord Klein and Noble Smith. 657 
434. Columns of the Cord 658 
435. Transverse Section of Gray Matter of Cord J. L. Clarice. 658 
436. Transverse Section of Gray Matter of Cord do. 659 
437. Longitudinal Section of Cord do. 660 
438. Transverse Section through the White Matter of the Cord Klein and Noble Smith. 660 
439. Transverse Section through Spinal Canal do. do. 660 
440. Medulla Oblongata and Pons Varolii, anterior surface 666 
441. Posterior Surface of Medulla Oblongata 666 
442. Transverse Section of Medulla Oblongata Arnold. 667 
443. The Columns of the Medulla Oblongata and their Connection with the 
Cerebrum and Cerebellum Altered from Arnold. 668 FIG. PAGE 
[444. Diagram of Gray Masses and Conducting Paths of Spinal Cord and Brain . . . Flechsig.] 670 
445. Plan of the Course of the Fibres through the Medulla to the Brain H. F. Clark. 671 
446. Upper Surface of the Brain, the arachnoid having been removed 673 
[447. View of Brain, from above Ecker.] 674 
[448. Outer Surface of Left Hemisphere do. ] 675 
[449. View of Brain, from below do. ] 677 
[450. Inner Surface of Eight Hemisphere . . . do. ] 678 
[451. Head, showing Motor Eegions of Brain Horsley.] 679 
[452. Head, showing Motor Eegions of Brain do. ] 680 
[453. Side View of Brain of Man, motor centres Ferrier.] 682 
[454. Top View of Brain of Man, motor centres do. ] 682 
[455. Cerebral Centres for Movements of Upper Face and Angle of Mouth Horsley.] 683 
[456. Cerebral Centres for Movements of Vocal Chords do. ] 683 
[457. Cerebral Centres for Movements of Lower Face and Floor of Mouth do. ] 683 
[458. Cerebral Centres for Movements of Shoulder • do. ] 683 
[459. Cerebral Centres for Movements of Elbow and Wrist do. ] 683 
[460. Cerebral Centres for Movements of Thumb do. ] 683 
[461. Cerebral Centres for Movements of Combined Synchronous Action of Both Limbs do. ] 683 
[462. Cerebral Centres for Movements of Lower Limb do. ] 683 
[463. Cerebral Centres for Movements of Head and Neck and Conjugate Deviation of 
Eyes ' do. ] 684 
[464. Skull, showing points named by Broca Broca.] 685 
[465. Fissures and Convolutions of Brain Horsley.] 686 
466. Base of the Brain 688 
467. Section of the Brain, made on a level with the corpus callosum 691 
[468. Cast of Cavities (Ventricles) of Brain Fere.] 692 
[469. Transverse Vertical Section of Human Brain Dalton.] 693 
[470. Horizontal Section of Brain of Child Flechsig.] 694 
471. The Lateral Ventricles of the Brain 695 
472. Transverse Vertical Section of the Brain After Hirschfeld and Leveille. 696 
473. Transverse Section of the Middle Horn of the Lateral Ventricle F. A. Barton. 697 
474. The Fornix, Velum Interpositum, and Middle or Descending Cornu of the 
Lateral Ventricle 698 
475. The Third and Fourth Ventricles 700 
476. Vertical Median Section of Encephalon, showing the parts in the middle line. After Sappey. 701 
477. Gray Matter of the Cerebral Cortex Meynert. 704 
478. Upper Surface of the Cerebellum 709 
479. Under Surface of the Cerebellum 709 
480. Vertical Section of the Cerebellum Arnold. 710 
481. Vertical Section through Gray Matter of Cerebellum Klein and Noble Smith. 712 
ILLUSTRATIONS. 
29 
Cranial Nerves. 
482. The Optic Nerves and Optic Tracts 717 
483. Course of the Fibres in the Optic Commissure Bowman. 717 
484. Nerves of the Orbit, seen from above After Arnold. 718 
485. Nerves of the Orbit and Ophthalmic Ganglion, side view do. 720 
[486. Diagram of Fifth Nerve and its Ganglia W. W. Keen.] 722 
487. Distribution of the Second and Third Divisions of the Fifth Nerve and 
Submaxillary Ganglion After Arnold. 724 
488. The Spheno-palatine Ganglion and its Branches 726 
489. The Otic Ganglion and its Branches After Arnold. 730 
[490. Sensory Nerves of Head and Face Flower.] 731 
491. Eelation of Structures passing through Sphenoidal Fissure 732 
492. The Course and Connections of the Facial Nerve in the Temporal Bone . . After Bidder. 732 
493. The Nerves of the Scalp, Face, and Side of the Neck 734 
494. Origin of the Glosso-pharyngeal, Pneumogastric, and Spinal Accessory Nerves, 
their Ganglia and Communications Bends. 736 
495. Course and Distribution of the Glosso-pharyngeal, Pneumogastric and Spinal 
Accessory Nerves 737 
496. Hypoglossal Nerve, Cervical Plexus, and their Branches 742 
Spinal Nerves. 
[497. Eelation of Spinal Nerves to Various Motor, Sensory, and Eeflex Functions 
of Spinal Cord Gowers.] 746 
498. Posterior Divisions o# the Upper Cervical Nerves 748 
499. Plan of the Cervical Plexus 751 
500. Plan of the Brachial Plexus 753 
[501, 502. Cutaneous Nerves of the Trunk and Upper Extremity FZower.] 757 
503. Cutaneous Nerves of Eight Upper Extremity, anterior view 758 
504. Cutaneous Nerves of Eight Upper Extremity, posterior view 758 
505. Nerves of the Left Upper Extremity, front view 760 
506. The Suprascapular, Circumflex, and Musculo-spiral Nerves 762 
507. The Posterior Branches of the Spinal Nerves After Hirschfeld and Leveille. 765 
508. Plan of the Lumbar Plexus 768 
509. The Lumbar Plexus and its Branches Altered from Quain. 769 
510. Cutaneous Nerves of the Lower Extremity, front view 771 
511. Nerves of the Lower Extremity, front view ' ' 771 
[512. Cutaneous Nerves of Lower Extremity Flower.] 772 30 
FIG. PAGE 
513. The Posterior Sacral Nerves Altered from Ellis. 776 
514. The Sacral Plexus and its Branches 777 
515. Cutaneous Nerves of the Lower Extremity, posterior view 779 
516. Nerves of the Lower Extremity, posterior view 779 
517. The Plantar Nerves 781 
[518. Diagram of the Sympathetic Nerve Flower.] 785 
519. The Sympathetic Nerve 786 
[520. Cervical and Thoracic Portion of the Sympathetic Nerve Sappey.] 787 
[521. Lumbar and Sacral Portions of the Sympathetic Nerve do. ] 788 
522. Ganglia and Nerves of Gravid Uterus After R. Lee. 795 
ILLUSTRATIONS. 
Organs of Sense. 
o 
523. Upper Surface of the Tongue 798 
524. The Three Kinds of Papillie of the Tongue, magnified Bowman. 798 
525. Minute Structure of Taste-goblet 800 
526. 527. Cartilages of the Nose Arnold. 802 
528. Bones and Cartilages of Septum of Nose, right side do. 803 
529. Nerves of Septum of Nose, right side do. 805 
[530. Horizontal Section of Eyeball Allen.] 807 
531. The Choroid and Iris, enlarged Altered from Zinn. 809 
532. The Veins of the Choroid, enlarged Arnold. 810 
533. The Arteries of the Choroid and Iris, the sclerotic having been mostly removed, 
enlarged Arnold. 811 
534. The Arteria Centralis Retinae, Yellow Spot, etc., the anterior half of the eyeball 
being removed, enlarged . 812 
535. 536. Vertical Sections of the Human Retina Frey. 813 
537. Layers of the Retina Altered from Schultze. 815 
538. The Crystalline Lens, hardened and divided, enlarged Arnold. 818 
539. The Meibomian Glands, etc., seen from the inner surface of the eyelids do. 820 
540. The Lachrymal Apparatus, right side 822 
541. The Pinna, or Auricle, outer surface 823 
542. The Muscles of the Pinna Arnold. 824 
543. A Front View of the Organ of Hearing, right side Scarpa. 825 
544. View of Inner Wall of Tympanum, enlarged 827 
[545. Vertical Section of Right Eustachian Tube, Tympanic Cavity, and Mastoid Cells . Politzer.] 828 
546. The Small Bones of the Ear, seen from the outside, enlarged Arnold. 829 
547. The Osseous Labyrinth, laid open, enlarged Sbmmerring. 832 
548. The Cochlea, laid open, enlarged Arnold. 834 
549. Longitudinal Section of the Cochlea, showing the relations of the scake, etc. . . C. Stewart. 834 
550. Floor of the Scala Media, showing the organ of Corti, etc do. 835 
551. The Membranous Labyrinth do. 837 
Organs of Digestion and tlieir Appendages. 
552. Sectional View of the Nose, Mouth, Pharynx, etc ... 840 
553. The Permanent Teeth, external view 842 
[554. Occlusion of Permanent Teeth Litch.] 842 
555. The Temporary or Milk Teeth, external view 843 
556. Vertical Section of a Molar Tooth 843 
557. Vertical Section of a Bicuspid Tooth, magnified After Retzius. 844 
558. Transverse Section of the Root of a Tooth Waldeyer. 844 
559. Vertical Section of the Lower Jaw of an Early Human Foetus do. 847 
560. Dental Sac of a Human Embryo, at an advanced stage of development Frey. 847 
[561. Denture of Seven-Year-Old Child Pitch.] 849 
562. The Salivary Glands 852 
563. Section of Submaxillary Gland « Kolliker. 853 
564. Termination of Nerves in Salivary Cells Pfliiger. 855 
565. Minute Anatomy of Compound Racemose Gland Saviotti. 855 
566. The Regions of the Abdomen and their Contents (edge of costal cartilages 
in dotted outline) 859 
567. The Reflections of the Peritoneum, as seen in a vertical section of the 
abdomen Altered from Quain. 861 
568. Plan of the Peritoneum 863 
[569. Layers of Peritoneum Cruveilhier.] 864 
570. The Reflection of the Peritoneum, as seen in a transverse section of the abdomen 866 
571. Diagram to show the Lines along which the Peritoneum leaves the Wall of the 
Abdomen to invest the Viscera Delepine. 868 
572. The Mucous Membrane of the Stomach and Duodenum, with the bile-ducts 871 
573. The Muscular Coat of the Stomach 872 
574. Minute Anatomy of Mucous Membrane of Stomach 873 
575. Relations of the Duodenum 875 
[576. Vertical Section of the Mucous Membrane of the Jejunum of a Dog Allen.] 876 
577. Diagrammatic Section of a Villus ' Watney. 878 
578. Two Villi, magnified 879 
579. Transverse Section of Crypts of Lieberkuhn Klein and Noble Smith. 879 
580. Longitudinal Section of Crypts of Lieberkuhn do. do. 879 
581. Transverse Section through three of Peyer's Follicles, from the rabbit Frey. 880 
582. Patch of Peyer's Glands, from the lower part of the ileum 880 
583. A Portion of the Above, magnified Boehm. 880 ILL USTRATIONS. 
31 
FIG. PAGE 
584. Vertical Section of one of Peyer's Patches, from man, injected through its 
lymphatic canals Frey. 881 
585. The Caecum and Colon laid open, to show the ileo-caecal valve 882 
586. Diagram of the Relations of the Large Intestine a'nd Kidneys, from behind 884 
587. The Relations of the Viscera and Large Vessels of the Abdomen, from behind 885 
588. Minute Structure of Large Intestine C. Stewart. 888 
589. Meissner's Plexus Klein and Noble Smith. 888 
590. The Liver, upper surface 890 
591. The Liver, under surface 890 
592. Longitudinal Section of an Hepatic Vein Kiernan. 893 
593. Longitudinal Section of a Small Portal Vein and Canal do. 893 
594. Vessels of Lobules of Liver Klein. 894 
595. Origin of Bile-ducts Herring. 895 
596. A Transverse Section of a Small Portal Canal and its Vessels Kiernan. 895 
597. The Pancreas and its Relations 898 
598. Transverse Section of the Spleen, showing the trabecular tissue and the 
splenic vein and its branches 900 
599. Transverse Section of the Human Spleen, showing the distribution of the 
splenic artery and its branches ■ ■ • . 901 
600. Part of Malpighian Capsule of Spleen Klein and Noble Smith. 902 
601. Minute Structure of Spleen 903 
The Thorax. 
602. Front View of the Thorax, showing the relation of the Thoracic Viscera to the walls 
of the Chest 905 
603. The Right Auricle and Ventricle laid open, the anterior walls of both being removed . . . 907 
604. The Left Auricle and Ventricle laid open, the posterior walls of both being removed . . . 910 
605. Plan of the Foetal Circulation 917 
Organs of Voice and Respiration. 
606. Side View of the Thyroid and Cricoid Cartilages 919 
607. The Cartilages of the Larynx, posterior view 920 
608. The Larynx and Adjacent Parts, seen from above 922 
609. Vertical Section of the Larynx and Upper Part of the Trachea 923 
{610. Laryngeal Image during Phonation Seiler.} 923 
[611. Laryngeal Image during Quiet Breathing Mackenzie.} 923 
612. Muscles of Larynx, side view, right ala of thyroid cartilage removed 925 
613. Interior of the Larynx, seen from above, enlarged Willis. 925 
614. Front View of Cartilages of Larynx : the Trachea and Bronchi 928 
615. Transverse Section of the Trachea, just above its Bifurcation, with a Bird's-eye 
view of the interior 928 
616. Surgical Anatomy of the Laryngo-tracheal Region 930 
•617. A Transverse Section of the Thorax, showing the relative position of the viscera 
and the reflections of the pleurae 932 
618. The Posterior Mediastinum 933 
619. Front View of the Heart and Lungs 935 
620. The Roots of the Lungs and Posterior Pulmonary Plexus, seen from behind 938 
■621. Minute Structure of Thyroid Gland Frey. 939 
622. Minute Structure of Thyroid Gland Baber. 940 
623. Minute Structure of Thymus Gland Frey. 942 
624. Minute Structure of Thymus Gland Watney. 943 
The Urinary and Generative Organs. 
625. Vertical Section of Kidney 945 
626. Uriniferous Tubes 946 
627. Minute Structure of Kidney 947 
628. Malpighian Body 947 
629. A Uriniferous Tube 948 
630. Descending Limb of Uriniferous Tube Klein. 949 
631. Straight Tube do. 949 
632. Transverse Section of Kidney do. 950 
633. Diagrammatic Sketch of Kidney 950 
634. A Portion of Fig. 633, enlarged 950 
635. Diagrammatic Representation of the Blood-vessels of the Cortex of the Kidney. . Ludwig. 951 
636. Vertical Section of Suprarenal Capsule '. . E lb er th. 954 
637. Cortical Portion of Suprarenal Capsule Frey. 954 
638. Transverse Section through the Cortical Substance of the Suprarenal Capsule .... do. 954 
639. Vertical Section of Bladder, Penis, and Urethra 956 
640. Superficial Layer of Epithelium of Bladder Klein and Noble Smith. 958 
641. Deep Layers of Epithelium of Bladder do. do. 958 
642. The Bladder and Urethra laid open 959 
[643. Diagram of Urethra in Natural Condition Thompson.} 960 
644. Transverse Section of the Prostate Gland 962 
{645. Cross-section of Penis Cruveilhier.} 964 
646. Structure of the Corpus Cavernosum Langer. 966 32 
ILLUSTRATIONS. 
FIG. PAGE 
647. Transverse Section through the Left Side of the Scrotum and the Left Testicle . Delepine. 967 
648. The Testis in situ 969 
649. Vertical Section of the Testis 972 
650. Base of the Bladder Haller. 973 
[651. Descent of Testes and Formation of Tunica Vaginalis ... Heath.] 974 
[652. Descent of Testes and Formation of Tunica Vaginalis do. ] 974 
[653. Descent of Testes and Formation of Tunica Vaginalis do. j 974 
654. The Vulva 976 
655. Section of Female Pelvis 977 
[656. Antero-posterior Section of Pelvic Organs of Virgin D. Berry Hart.] 978 
[657. Horizontal Section of Body, showing relations of fundus uteri Savage.] 980 
[658. Ovarian, Uterine, and Vaginal Arteries Hyrtl.] 982 
[659. Posterior View of Uterine Appendages Henle.] 985 
660. The Uterus and its Appendages Wilson. 985 
661. Section of an Ovary t Schron. 986 
662. Section of a Graafian Vesicle Von Baer. 986 
The Surgical Anatomy of Inguinal Hernia. 
663. Inguinal Hernia, superficial dissection 992 
664. Inguinal Hernia, showing the internal oblique, cremaster, and spermatic canal . ..... 994 
665. Inguinal Hernia, showing the Transversalis Muscle, the transversalis fascia, and 
the internal abdominal ring 995 
[666. Diagram of Coverings of Hernia W. W. Keen.] 997 
667. Varieties of Oblique Inguinal Hernia 998 
668. Femoral Hernia, superficial dissection 1002 
669. Femoral Hernia, showing fascia lata and saphenous opening 1003 
670. Femoral Hernia, showing femoral canal 1005 
671. Structures which Pass beneath Femoral Arch 1006 
672. Hernia, the Relations of the Femoral and Internal Abdominal Rings 1006 
Surgical Anatomy of the Perineum and Ischio-rectal Region. 
673. Dissection of the Perineum and Ischio-rectal region 1001 
674. The Perineum, superficial dissection 1012 
675. The Superficial Muscles and Vessels of the Perineum 1013 
[676. Muscles of Female Perineum Savage-Luschka.'] 1015 
[677. Female Perineum Savage.] 1016 
[678. Structures between the Two Layers of Deep Perineal Fascia Wilson.] 1017 
679. Deep Perineal Fascia 1018 
680. A View of the Position of the Viscera at the Outlet of the Pelvis 1019 
681. A Transverse Section of the Pelvis, showing the pelvic fascia from behind . After Wilson. 1029 
682. Side View of the Pelvic Viscera of the Male Subject, showing the pelvic and 
perineal fascia 1022 
LANDMARKS, MEDICAL AND SURGICAL. 
383. Outline of the Heart, its Valves, and the Lungs 1035 
[684. Diagram showing the Approximate Relation to the Spinal Nerves of the 
various Motor, Sensory, and Reflex Functions of the Spinal Cord Gowers.] 1039 
685. Opisthotonos . 1040 ON THE SYSTEMATIC USE OF THE LIVING MODEL AS A 
MEANS OF ILLUSTRATION IN TEACHING ANATOMY. 
The following paper (here slightly altered and expanded) was read by the Amer- 
ican Editor at the London International Medical Congress in 1881, and is reprinted 
in the hope that it will stimulate anatomical teachers to use the living model in their 
lectures, and students to observe the same facts on each other or on their own 
persons. In his own anatomical lectures the Editor has used this method now for 
some seventeen or eighteen years, and it has been his experience that not a few 
teachers, as well as many pupils, have expressed their interest and profit in observ- 
ing the marked advantages of the method. It throws an entirely new light on the 
practical applications of anatomy to the every-day wants of the doctor, and enlivens 
what is otherwise not seldom a dry subject. No teacher who ever tries it will ever 
be willing to dispense with it. 
" In one sense, what I wish to suggest is not a novelty. Long ago, Sir Charles 
Bell, having learned the value of the living model in his lectures on fractures and 
dislocations, was accustomed to introduce a powerful muscular fellow to his class with 
the striking and suggestive remark that, however familiar they might be with the 
body as affected by disease or accident, ' not one of them, perhaps, had ever looked 
on the natural body itself.' Of late, Mr. Christopher Heath has followed out Bell's 
idea in more than one noteworthy publication, while Mr. Holden in his ' Landmarks, 
Medical and Surgical,' has given us an admirable illustration of how much anatomy 
may be learned by a careful study of the exterior of the body. 
" What I wish, therefore, formally to urge upon teachers of anatomy is not that 
the living model should be used occasionally, but regularly ; not as a rarity, but as 
a constant means of illustration-as much so as the cadaver or the skeleton. 
" In disease we have not to deal with the dissected body, but with the normal 
living, moving body; and while it is needful that we know each dissected part, yet 
if we would know the body thoroughly and practically we must study it as a recon- 
structed undissected whole. Accustomed to the normal form, relation, and consist- 
ence, the eye and the hand can well judge in the clinic room of what is abnormal; 
and no dissection of the dead body-altered not only by post-mortem change, but 
also by artificial means for preservation from decay, and by altered relations from 
the removal of the skin and further dissections-can replace such familiarity. 
" What might be called ' Postural Anatomy ' is almost impossible in the dead. 
The subject must lie practically on the back or the belly, with muscles relaxed, 
motionless arms and legs. The living model can simulate the patient; can stand, 
sit, stoop, lie on the back, etc.; bend forward, backward, laterally; swing the arms 
or legs, flex, extend, abduct, adduct them; can expire or inspire; can contract or 
relax at will all the muscles or a single one,-thus changing not only the outline of 
the body in general, but the local forms, the resistance of the tissues, the reciprocal 
relations of bones, joints, muscles, vessels, and viscera; the arteries can be felt beat- 
ing in many parts of the body, and their bony, muscular, or mathematical relations 
studied; the veins can be filled by moderate constriction; the form, extent, and 
consistence of the chief abdominal and thoracic viscera can be accurately deter- 
mined. And when the anatomist has shown the part under discussion in the dis- 
33 USE OF THE LIVING MODEL. 
34 
sected body, he then turns to the living model and shows it there by the eye, by 
the touch, by measurement from some fixed point, by line, or by percussion. 
u Not only should the model be used passively, as it were-that is, at rest-and 
actively by various gestures in various postures, etc., but especially by strongly- 
resisted motions. This may be by lifting heavy weights, swinging from rings by 
one or both arms, lifting the body while holding on to the rings or a bar, and by 
seizing the arm, leg, etc. of the model and resisting his motions in various actions. 
The female model also should be used to some extent, and under proper restrictions, 
in order to show the differences of form, motion, posture, development, etc. 
" Of course, in many parts of the body the living model, like the cadaver, is not 
needed for lecture purposes; but in studying the bones, joints, muscles, arteries, 
veins, most nerves and most viscera, he should be always at hand for ready refer- 
ence. The model should be varied, like the cadaver, to suit the object in view-a 
muscular athlete being selected when on the muscles, a leaner man for the arteries, 
nerves, etc. These last can be admirably indicated by the now commonly used 
so-called indelible pencil with aniline lead, which, by previously wetting the skin, 
will instantly mark a purple line, dot, cross, etc., or by it the name of the part, if 
desired, can be written on the moistened skin. The eye of the student thus catches 
what the touch and the observation of the teacher have ascertained. The position 
of the palmar arches and of Poupart's ligament are striking illustrations of this. 
Unless the relation of the arches to the web of the thumb be pointed out, any 
student from his dissection would inevitably place them much lower down than they 
really are, because, in dissecting, the skin has been removed long before the arteries 
have been reached; and unless Poupart's ligament be accurately determined by 
fixing ks bony attachments by touch, and then drawing its line, we are very apt to 
mistake inguinal and femoral hernia. 
" Incidentally, also, I may say that I have found it very useful to study the 
cadaver, not only horizontally, on a rotating table, as we generally do, but in the 
vertical position. I place two hooks in the skull, just above the ears, and suspend 
the body from the ceiling by a pulley, using also a cross-piece with cords and self- 
adjusting pulleys, by which the arms can be raised at will and the body easily 
rotated. The skeleton, cadaver, and model are thus all in the same posture, and 
no mental transposition of relations is necessary in passing from the one to the 
other." 
In revising this edition of Gray's Anatomy I have indicated in many places 
what can be learned by the above method. In the case of the muscles I have 
suggested special gestures and resisted motions by which particular muscles may 
best be shown. My experience at the Academy of the Fine Arts, however, shows 
me that models vary very much in this respect, as well as in their comprehension 
of just what action is desired, and teachers may find that other gestures or poses 
than the one stated may bring the muscles into better relief in other models. ANATOMY, 
DESCRIPTIVE AND SURGICAL. 
GENERAL ANATOMY. 
THE fluids of the body, which are intended for its nutrition, are the lymph, the 
chyle, and the blood. There are other fluids also which partially subserve 
the same purpose, as the saliva, the gastric juice, the bile, the intestinal secretion; 
and others which are purely excrementitious, as the urine. But there is no need 
to describe the rest in this place, since they are the secretions of special organs, and 
are described, as far as is judged necessary for the purposes of this work, in sub- 
sequent pages. We shall here speak first of the blood, and next of the lymph and 
chyle. 
THE BLOOD. 
The blood is a thickish, opaque fluid, of a bright red or scarlet color when it 
flows from the arteries, of a dark red or purple color when it flows from the veins. 
It is viscid, and has a somewhat clammy feeling; it is salt to the taste, and has a 
peculiar faint odor. It has an alkaline reaction. Its specific gravity at 60° F. is 
about 1.055, and its temperature is generally about 100° F., though varying slightly 
in different parts of the body. 
General Composition of the Blood.-When blood is drawn from the body and 
allowed to stand, it solidifies in the course of a very few minutes into a jelly-like 
mass, which has the same appearance and volume as the fluid blood, and, like it, 
looks quite uniform. Soon, however, drops of a transparent yellowish fluid begin 
to ooze out from the surface of this mass and to collect around it. Coincidently 
with this the clot begins to contract, so that in the course of about twenty-four 
hours the original mass of coagulated blood has become separated into two parts: 
a "clot" or "coagulum," considerably smaller and firmer than the first-formed 
jelly-like mass, and a large quantity of yellowish fluid, the serum, in which the 
clot floats. 
The clot thus formed consists of a solid, colorless material called fibrin, and 
a large number of minute cells or corpuscles called blood-corpuscles, which are 
entangled and enclosed in the fibrin. The fibrin is formed during the act of solidi- 
fication. In the fluid blood in the living body there are two substances, named 
fibrinogen and fibrino-plastin, which may be termed fibrin-factors. These two 
materials, when withdrawn from the body, become acted upon by a third material, 
also contained in the blood, and named a fibrin-ferment, and unite together, form- 
ing a solid substance, fibrin. This latter in its process of solidification encloses and 
entangles the blood-corpuscles, and thus the clot is formed. 
We may now consider the constituents of the blood in another way : If a drop of 
35 36 
GENERAL ANATOMY. 
blood is placed in a thin layer on a glass slide and examined under the microscope, 
it will be seen to consist of a number of minute bodies or corpuscles floating in a 
clear fluid; and on more minute examination it will be found that these corpuscles 
are of two kinds. The one kind, greatly preponderating over the other in point of 
numbers, are termed the colored corpuscles; the other, fewer in number and less con- 
spicuous, are termed the colorless corpuscles. From this we learn that blood is a 
fluid holding a large number of corpuscles of two varieties in suspension. The 
fluid is named liquor sanguinis, or plasma, and must not be confused with the serum 
spoken of above in connection with the coagulation of the blood. It is serum and 
something more, for it contains one at least of the elements or factors from which 
fibrin is formed. The relation of these various constituents of blood to each other 
will be easily understood by a reference to the subjoined plan: 
Corpuscles 
Colored 
Colorless 
Blood. 
Fibrin 
Clot. 
Liquor sanguinis 
Serum. 
The blood-corpuscles, blood-disks, blood-globules are, as before stated, of 
two kinds: the red or colored, and the white or colorless corpuscles. The relative 
proportion of the one to the other has been variously estimated, and no doubt varies 
under different circumstances. Thus venesection, by withdrawing a large propor- 
tion of the red globules, and by favoring the absorption of lymphatic fluid into the 
blood, greatly increases the relative proportion of the white corpuscles. Klein 
states that in healthy human blood there appears to be one white corpuscle for 
600-1200 red ones. The proportion of corpuscles, colored and colorless combined, 
to liquor sanguinis is in one hundred volumes of blood about thirty-six volumes of 
the former to sixty-four of the latter. 
Colored corpuscles when examined under the microscope are seen to be cir- 
cular disks, biconcave in profile, having a slight central depression, with a raised 
border (Fig. 1, 6). When viewed with a moderate magnifying power, this central 
depression looks darker than the edge. When exam- 
ined singly by transmitted light, their color appears to 
be of a faint reddish-yellow when derived from arterial 
blood, and greenish-yellow in venous blood. It is to 
their aggregation that blood owes its red hue. Their 
size varies slightly even in the same drop of blood, but 
it may be stated that their average diameter is about 
■3Toir an inch, their thickness about 000? or nearly 
one-quarter of their diameter. Besides these, especially 
in some anaemic and diseased conditions, certain cor- 
puscles are found of a much smaller size, about one- 
third or one-half the size of the ordinary one. These, 
however, are very scarce in normal blood. The num- 
ber of red corpuscles in the blood is enormous; between 4,000,000 and 5,000,000 
are contained in a cubic millimeter. Power states that the red corpuscles of an adult 
would present an aggregate surface of about 3000 square yards. Human blood- 
disks present no trace of a nucleus. They consist of a tough, elastic, transparent 
stroma, uniformly pervaded by a coloring matter named haemoglobin. Haemoglobin 
is a proteid compound of a very complex constitution (C600, H960, N154, FeS3, O170). 
It has a great affinity for oxygen, and when removed from the body crystallizes 
readily under certain circumstances. It is readily soluble in water, and the addition 
of this fluid to a drop of blood speedily dissolves out haemoglobin from the cor- 
puscle. 
If the web of a frog's foot is spread out and examined under the microscope, 
the blood is seen to flow in a continuous stream through the vessels, and the 
corpuscles show no tendency to adhere to each other or to the wall of the vessel. 
Fig. 1. 
Human Blood-globules: a, seen from 
the surface; b, seen from the side; 
c, united in rouleaux; d, rendered 
spherical by water; e, decolorized 
by the same; f, blood-globules 
shrunk by evaporation. THE BLOOD. 
37 
Doubtless the same is the case in the human body; but when drawn and examined 
on a slide without reagents, the blood-globules often collect into heaps like rouleaux 
of coins (Fig. 1, c). 
During life the red corpuscles may be seen to change their shape under pres- 
sure, so as to adapt themselves to some extent to the size of the vessel. They are 
also highly elastic, for they speedily recover their shape when the pressure is 
removed. They are soon influenced by the medium in which they are placed 
and by the specific gravity of the medium. In water they swell up, lose their 
color, and cease to be visible, leaving the white corpuscles in the field. Solutions 
of salt or sugar, denser than the serum, give them a stellate or crenated appear- 
ance, and the usual shape may be restored by diluting the solution to the proper 
point. The same crenated outline may be produced as the first effect of the 
passage of an electric shock. A solution of salt or sugar of the same specific 
gravity as serum merely separates the blood-globules mechanically without chang- 
ing their shape. 
The white corpuscles (Fig. 2) are rather larger than the red in human blood, 
measuring from about -2 to 2 0- of an inch in diameter. W hen absolutely at 
rest they are rounded or spheroidal, but 
under ordinary circumstances then* form 
is very various, and they have the re- 
markable property of undergoing " amoe- 
boid" changes (Fig. 3). That is to say, 
they have the power of sending out fin- 
ger-shaped or filamentous processes of 
their own substance, by which they 
move and take up granules from the 
surrounding substance. In locomotion 
the corpuscle pushes out a process of its 
substance-a pseudopodium, as it is 
called-and then shifts the rest of the 
body into it. In the same way, when any granule or particle comes in its way it 
wraps a pseudopodium round it, and then, withdrawing it, lodges the particle in its 
own substance. By means of these amoeboid properties they have the power of 
Fig. 2. 
a, white corpuscles of human blood; cZ, red corpuscles 
(high power). 
Fig. 3. 
Human colorless Blood-corpuscle, showing its successive changes of outline within ten minutes when kept 
moist on a warm stage (Schofield). 
wandering or emigrating from the blood-vessels by penetrating their coats, and thus 
finding their way into the perivascular spaces. 
The white corpuscle may be taken as the type of a true animal cell. It has no 
limiting membrane, but consists of a mass of transparent albuminous substance, 
called protoplasm, containing one or more nuclei. These nuclei become more per- 
ceptible on the addition of acetic acid. The protoplasm contains bright granules, 
generally of a fatty nature. 
The white corpuscles are very similar to, if not identical with, the corpuscles of 
lymph and chyle, and they also bear a strong resemblance to the cells found in pus. 
From the fact that cells exactly like the colorless corpuscles are being constantly 
furnished to the blood by the lymphatic vessels, the chyle-ducts (and even the 
liver in the foetus), and also from their varying proportions in different parts of 
the circulation and in different pathological conditions, the colorless corpuscles 
are often regarded-with, at any rate, some probability-as an earlier stage of the 
colored blood-disks, but the evidence in favor of this cannot be regarded as con- 
clusive. 38 
GENERAL ANATOMY. 
There can be no doubt that during embryonic life the white corpuscles, which 
are first formed from certain cells of the mesoblast, are converted into red corpus- 
cles. Another important source of the red corpuscles is the red marrow of bones, 
in which the marrow-cells are converted into colored blood-corpuscles by the loss of 
their nuclei and by their protoplasm becoming tinged with yellow. It is probable, 
also, that the spleen may be a place for the formation of red corpuscles. This the- 
ory, which was formerly universally believed, and was then discarded for the hypoth- 
esis that the spleen was concerned in the destruction of the red corpuscles, has 
lately been revived by Bizzozero. The question must still be regarded as sub 
judice. The proportion of white corpuscles appears to vary considerably in differ- 
ent parts of the circulation, being much larger in the blood of the splenic vein and 
hepatic vein than in other parts of the body, while in the splenic artery they are 
very scanty. 
[Blood-plaques.-There is also a "third corpuscle" in the blood, known vari- 
ously as " haematoblasts " and by other names, but best by the name given them by 
Bizzozero, "blood-plates" or "blood-plaques." 
They are colorless protoplasmic disks, constant 
in mammalian blood, measuring 1.5 to 3.5 micro- 
millimeters, and about in the ratio of one to 
eighteen or twenty red ones, as a rule. They 
are colorless, homogeneous, or finely granular, 
probably without a nucleus. They are increased 
in number in a large number of diseases, and 
bear an important relation to the coagulation 
of the blood, and especially to the formation of 
thrombi. (For the most recent views on this 
interesting element in the blood, see Prof. Wm. 
Osier's " Cartright Lectures," Med. News, April 
3, 1886.)] 
The liquor sanguinis, or plasma, is the fluid part of the blood, and is composed 
of a permanently fluid portion, the serum, and of fibrin-factors, which unite spon- 
taneously when out of the body, and by their union form a solid substance, fibrin. 
These two fibrin-factors are named fibrinogen and fibrino-plastin or paraglobulin. 
Fibrino-plastin is probably contained partly in solution in the plasma and partly in 
the colorless corpuscles, and can be obtained by diluting the liquor sanguinis with 
ten times its volume of ice-cold water, and then transmitting through it a stream 
of carbon dioxide. Fibrinogen may be obtained in the same way as fibrino-plastin, 
but the liquor sanguinis must be still further diluted and the current of carbon 
dioxide must pass for a much longer time. When these two fibrin-factors are with- 
drawn from the body, their union to form fibrin is probably brought about by the 
agency of a third body, called a fibrin fi'erment. This ferment is not supposed to 
pre-exist in the blood, but is formed after the blood is withdrawn from the body by 
the breaking down of some of the white corpuscles. Fibrin may be obtained by 
whipping the blood, after it has been withdrawn from the body, with a bundle of 
twigs, to which the fibrin, as it coagulates, adheres. Fibrin may also be obtained 
by filtering the freshly-drawn blood of an animal in whom the corpuscles are 
large, care being taken to retard coagulation as long as possible. Under these 
circumstances the corpuscles are retained on the filter, ancl the liquor sanguinis, 
passing through, coagulates and separates into fibrin, free from corpuscles and 
serum. 
Fibrin, thus obtained, is a white or buff-colored substance, presenting a stringy 
appearance, and under the microscope exhibiting fibrillation. When exposed to the 
air for some time it becomes hard, dry, brown, and brittle. It is a proteid com- 
pound, insoluble in hot or cold water, alcohol, or ether. Under the influence of 
dilute hydrochloric acid it swells up, but does not dissolve; but when thus swollen 
it is easily dissolved by a solution of pepsin. If heated for a considerable time in a 
solution of dilute hydrochloric acid, it gradually dissolves. 
[Fig. 4. 
Isolated Plaques in Normal Blood-osmic 
acid, 1 per cent, (one-twelfth im.; Ziess): 
a, red corpuscles; b, a white corpuscle; 
c, c, plaques with slightly irregular mar- 
gins ; d, plaque with faint granular ap- 
pearance in centre, as if nucleated (Osler).] LYMPH AND CHYLE. 
39 
Serum is the fluid liquor sanguinis after the fibrin-factors have been separated 
from it. It is a straw-colored fluid, having a specific gravity 1.027, with an alkaline 
reaction. Upon boiling it becomes solid, on account of the albumen which it con- 
tains. It contains also salts, fatty matters, sugar, and gases. 
Gases of the Blood.-When blood is exposed to the vacuum of an air-pump, 
about half its volume is given off in the form of gases. These are carbonic acid, 
oxygen, and nitrogen. The relative quantities in 100 volumes of arterial and venous 
blood, at 0° C. and 1 m. pressure of mercury, are shown in the accompanying table: 
Oxygen. 
Carbonic Acid. 
Nitrogen. 
Arterial blood . . . 
. . 16 vols. 
30 vols. 
1 to 2 vols. 
Venous blood . . . 
. . 6 to 10 vols. 
35 vols. 
1 to 2 vols. 
Roughly stated, they are as follows: Carbonic acid, about two-thirds of the whole 
quantity of gas, oxygen rather less than one-third, nitrogen below one-tenth (Hux- 
ley). The greater quantity of the oxygen is in loose chemical combination with 
the haemoglobin of the blood-corpuscles, but some part is simply absorbed, just as 
it would be by water. The carbonic acid is in a state of chemical combination 
with the salts of the serum, especially the sodium, with which it is combined, partly 
as a carbonate and partly as a bicarbonate. The nitrogen is unimportant. It 
(or at least the greater part of it) is merely absorbed from the atmosphere under 
the pressure to which the blood is exposed, and can therefore be mechanically 
removed. 
Blood-crystals.-Haemoglobin, as stated above, when separated from the blood- 
corpuscles, readily undergoes crystallization. These crystals, named hcemoglobin 
crystals, all belong, with the exception of those obtained from the squirrel, to the 
rhombic system. In human blood they are elongated prisms (Fig. 5, a). In the 
squirrel they are hexagonal plates. Other crystals may be obtained by mixing dried 
Fig. 5. 
Blood-crystals: a, Haematin Crystals from Human Blood. B, Haemin Crystals from Blood treated with Acetie 
Acid, c, Haematoidin Crystals from an old Apoplectic Clot. 
blood with an equal quantity of common salt and boiling it with a few drops of 
glacial acetic acid. A drop of the mixture placed on the slide will show the crys- 
tals on cooling. These are named haemin crystals, and consist of small acicular 
prisms (Fig. 5, b). Occasionally in old blood-clots a third form of crystal is found, 
the haematoidin crystal (Fig. 5, c). 
LYMPH AND CHYLE. 
The Lymph is a transparent, colorless, or slightly yellow fluid, which is con- 
veyed by a system of vessels, named lymphatics, into the blood. These vessels 
take their rise in nearly all parts of the body, and take up from the worn-out tissues 
that portion which is still available for purposes of nutrition, and return it into the 
veins close to the heart, there to be mixed with the mass of the blood. The greater 40 
GENERAL ANA TOM Y. 
number of these lymphatics empty themselves into one main duct, the thoracic duct., 
which passes along the front of the spine and opens into one of the large veins at 
the root of the neck. The remainder empty themselves in a smaller duct, which 
terminates in the corresponding vein on the opposite side of the neck. 
The Chyle is an opaque, milky-white fluid, absorbed by the villi of the small 
intestines from the food, and carried by a set of vessels similar to the lymphatics, 
named lacteals, to the commencement of the thoracic duct, where it is intermingled 
with the lymph and poured into the circulation through the same channels. It 
must be borne in mind that these two sets of vessels, lymphatics and lacteals, 
though differing in name, are identical in structure, and that the character of 
the fluid they convey is different only while digestion is going on. At other times 
the lacteals convey a transparent, nearly colorless fluid not to be distinguished from 
lymph. Both these sets of vessels, in their passage to the central duct, pass through 
certain small glandular bodies, termed lymphatic glands, where their contents 
undergo elaboration. 
Lymph, as its name implies, is a watery fluid. It closely resembles the liquor 
sanguinis, and contains about 5 per cent, of albumen and 1 per cent, of salts. 
When examined under the microscope it is found to consist of a clear colorless 
fluid in which are floating a number of corpuscles, lymph-corpuscles. The bodies 
are identical in structure, and not to be distinguished from the white blood-cor- 
puscles previously described. They vary in number in different parts of the 
lymphatic vessels, and indeed are said by Kolliker to be absent in the smaller 
ones. They are always increased in number after the passage of the lymph through 
a lymphatic gland, and are said to be increased in size as the fluid ascends higher 
in the course of the circulation. 
Chyle is a milk-white fluid which exactly resembles lymph in its physical and 
chemical properties, except that it has, in addition to the other constituents of 
lymph, an enormous number of fatty granules, "the molecular basis of chyle;" and 
it is to the presence of these molecules that chyle owes its milky color. Under the 
microscope it presents a number of corpuscles, named "chyle-corpuscles," which 
are indistinguishable from lymph-corpuscles or white blood-cells, and the molecular 
basis, consisting principally of fatty granules of extreme minuteness (Fig. 6, a), but 
also of a few small oil-globules. Lymph and chyle 
after their passage through their respective glands, 
if withdrawn from the body and allowed to stand, 
separate more or less completely into a clear liquid, 
which is identical with the serum of the blood, and 
a thin jelly-like clot consisting of fibres in which 
lymph-corpuscles or chyle-corpuscles and fatty mole- 
cules, as the case may be, are entangled. 
If the contents of the thoracic duct are examined, 
especially after a meal, there may be found in it cor- 
puscles with a reddish tinge. These are regarded 
as immature red corpuscles, or lymph- and chyle- 
corpuscles in process of transformation into blood- 
globules. They frequently give to the surface of 
clotted chyle and lymph a pinkish hue. They must 
not be mistaken for mature blood-globules, which 
are sometimes found in lymph and chyle, and which are regarded by most observers 
as accidental-i. e. produced by the manipulations of the dissector. 
Fig. 6. 
Chyle from the Lacteals. 
THE ANIMAL CELL. 
All the tissues and organs of which the body is composed were originally devel- 
oped from a microscopic body (the ovum), consisting of a soft, gelatinous, granular 
material enclosed in a membrane, and containing a vesicle, or small spherical body, THE ANIMAL CELL. 
41 
inside which are one or more solid spots. (See Fig. 79.) This may be regarded as 
a perfect cell. Moreover, all the solid tissues can be shown to consist largely of 
similar bodies, differing, it is true, in external form, but essentially similar to an 
ovum. These are also cells. 
In the higher organisms all such cells may be defined as " nucleated masses of 
protoplasm of microscopic size." The two essentials, therefore of an animal cell 
in the higher organisms are the presence of a soft, gelatinous, granular material, 
similar to that found in the ovum, and which is usually styled protoplasm, and a 
small spherical body imbedded in it, and termed a nucleus ;x the remaining con- 
stituents of the ovum-viz. its limiting membrane and the solid spot contained in 
the nucleus, called the nucleolus-not being considered essential to the cell, and in 
fact many cells existing without them. 
Protoplasm (sarcode, blastema, germinal matter, or bioplasm) is a proteid com- 
pound wThich cannot analytically be distinguished from albumen. It is of a semi- 
fluid, viscid consistence, and appears either as a hyaline substance, homogeneous 
and clear, or as a granular substance, consisting of minute molecules imbedded in a 
transparent matrix. The molecules are regarded by some as adventitious material 
taken in from without, and often probably of a fatty nature, since they are fre- 
quently soluble in ether. Under certain circumstances protoplasm shows a more 
definite structure, consisting of minute striae or fibrils arranged in a clear trans- 
parent matrix, or even a honeycombed reticulum, containing in its interstices a 
homogeneous substance. Protoplasm is insoluble in water, coagulates at 130° F., 
and has a great affinity for certain staining reagents, as logwood or carmine. 
The most striking characteristics of protoplasm are its vital properties of motion 
and nutrition. By motion is meant the power which protoplasm has of changing 
its shape and position by some internal power in itself, which enables it to thrust 
out from its main body an irregular process, into which the whole of the protoplas- 
mic substance is gradually drawn, so that the mass comes to occupy a new position. 
This, on account of its resemblance to the movements observed in the amoeba or 
proteus animalcule, has been termed "amoeboid movement." Ciliary movement, 
or the vibration of hair-like processes from the surface of any structure, may also 
be regarded as a variety of the motion with which protoplasm is endowed. Nutri- 
tion is the power which protoplasm has of attracting to itself the materials of growth 
from surrounding matter. When any foreign particle comes in contact with the 
protoplasmic substance, it becomes incorporated in it by being enwrapped by one or 
more processes projected from the parent mass and enclosing it. When thus taken 
up, it may remain in the substance of the protoplasm for some time without change, 
and finally may be extruded again. 
The Nucleus is a minute body imbedded in the protoplasm, and usually of a 
spherical or oval form, its size generally varying in proportion to the size of the 
cell. It is usually surrounded by a well-defined wall, and is regarded as a portion 
of the protoplasmic substance set apart for the purposes of reproduction. It differs 
chemically from the ordinary protoplasm in containing nuclein, in its power of 
resisting the action of acids and alkalies, in its imbibing more intensely the stain 
of carmine, haematoxylin, etc., and in its remaining unstained by some reagents 
which color ordinary protoplasm; as, for example, nitrate of silver. 
The process of reproduction commences in the nucleus, and may be brought 
about either by segmentation or by gemmation. In reproduction by segmentation 
or fission the nucleus first splits by becoming constricted in its centre, and thus 
assuming an hour-glass shape. This leads to a cleavage or division of the whole 
protoplasmic mass of the cell; and thus we find that two new cells have been 
formed, consisting of the same substance as the original one, and each containing 
a nucleus. These daughter-cells are of course at first smaller than the original 
mother-cell; but they grow, and the process may be repeated in them, so that 
multiplication may rapidly take place. This mode of division or cleavage is termed 
1 Tn certain lower forms of life masses of protoplasm without any nucleus have been described by 
Huxley and others as cells. 42 
GENERAL ANATOMY. 
direct division, in contradistinction to another mode of division, in which the nucleus 
shows slow movements and complicated changes prior to its division. This is termed 
indirect division, or karyokinesis. These changes consist briefly in the fibrils of the 
nuclear network becoming convoluted, and thus forming a sort of rosette or star- 
shaped figure. This subsequently divides into two stars, around each of which a 
membrane appears, and thus we have two new or daughter-nuclei. The cell-pro- 
toplasm subsequently either divides, and we thus get two complete cells, or, remain- 
ing undivided, we have a two-nucleated cell. 
In reproduction by gemmation, a budding-off or separation of a portion of the 
nucleus and parent-cell takes place, and, becoming separated, forms a new organism. 
The cell-wall, which is not an essential constituent, and in fact is often absent, 
consists of a flexible, transparent, structureless or finely-striated membrane which 
is permeable to fluids. As far as is known, every animal cell is derived from a 
pre-existing cell. The death of cells is accomplished either by their mechanical 
detachment from the surface, preceded possibly by their bursting and discharging 
their contents, or by various forms of degeneration-fatty, pigmentary, or calcareous. 
EPITHELIUM. 
All the surfaces of the body-the external surface of the skin, the internal sur- 
face of the digestive and respiratory tracts, the closed serous cavities, the inner coat 
of the vessels, and the ducts of all glands-are covered by one or more layers of 
simple cells, called epithelium or epithelial cells, which serve various purposes, both 
as a protective layer and as an agent in secretion. Thus, in the skin the main 
purpose served by the epithelium (here called the epidermis') is that of protection. 
As the surface is worn away by the agency of friction or change of temperature 
new cells are supplied, and thus the surface of the true skin and the vessels and 
nerves which it contains are defended from damage. In the gastro-intestinal mucous 
membrane and in the glands the epithelial cells appear to be the principal agents in 
separating the secretion from the blood or from the alimentary fluids. In other sit- 
uations (as the nose, fauces, and respiratory passages) the chief office of the epithe- 
lial cells appears to be to maintain an equable temperature by the moisture with 
which they keep the surface always slightly lubricated. In the serous cavities they 
also keep the opposed layers moist, and thus facilitate their movements on each 
other. Finally, in all internal parts they ensure a perfectly smooth surface. 
Of late years there has been a tendency on the part of many histologists to 
divide these several epithelial linings into two classes-into (1) epithelial tissue 
proper, consisting of nucleated protoplasmic cells, which form continuous masses 
on the skin and mucous surfaces and the linings of the ducts and alveoli of secret- 
ing and excreting glands; and (2) endothelium, which is composed of a single layer 
of flattened transparent squamous cells, joined edge to edge in such a manner as to 
form a membrane of cells. This is found on the free surfaces of the serous and 
synovial membranes, as the lining membrane of the heart, blood-vessels, and lymph- 
atics ; on the surface of the brain and spinal cord; and in the anterior chamber of 
the eye. And, though the separation must be an artificial one, since every grada- 
tion of transition between the two classes may be observed, it would seem advisable 
for the purposes of description to employ it. 
1. True epithelial tissue consists of one or more layers of cells united together 
by an interstitial cement-substance, supported on a basement-membrane, and natu- 
rally group themselves into two classes, according as there are a single layer of cells 
(simple epithelium) or more than one (stratified epithelium). The various kinds of 
epithelium, whether arranged in a single layer or in more than one layer, are usually 
spoken of as tessellated or pavement, columnar, spheroidal or glandular, and ciliated. 
The pavement epithelium (Fig. 7) is composed of flat nucleated scales of various 
shapes, usually polygonal, and varying in size. These cells fit together by their edges 
like the tiles of a mosaic pavement. The nucleus is generally flattened, but may be EPITHELIUM. 
43 
spheroidal. The flattening depends upon the thinness of the cell. The protoplasm 
of the cell presents a fine reticulum or honeycombed network, which gives to the cell 
the appearance of granulation. This kind of epithelium is found on the surface of 
Fig. 7. 
Epithelial Cells in the Oral Cavity of Man (magnified 350 times): a, large; b, middle-sized; c, the same with 
two nuclei. 
the skin (epidermis) and on mucous surfaces which are subjected to friction. The 
nails, hairs, and in animals the horns, are a variety of this kind of epithelium. 
The columnar or cylindrical epithelium (Fig. 8) is formed of cylindrical or rod- 
shaped cells, each containing a nucleus, and set together so as to form a complete 
membrane. The cells have a prismatic figure, more or less flattened from mutual 
pressure, and are set upright on the surface on which they are supported. Their 
protoplasm is always more or less longitudinally striated, and they contain a nucleus 
which is oval in shape and contains an intranuclear network. 
This form of epithelium covers the mucous membrane of nearly the whole gastro- 
intestinal tract and the glands of that part, the greater part of the urethra, the vas 
deferens, the prostate, Cowper's glands, Bartholini's glands, and a portion of the 
uterine mucous membrane. 
Fig. 8. 
Fig. 9. 
Epithelium of the Intestinal Villi of the Rab- 
bit (magnified 300 times): a, basement-mem- 
brane. 
Simple Columnar Epithelium from the Mucous Mem. 
brane of the Intestine, with goblet-cells pouring out 
their contents (Klein and Noble Smith). 
Groblet or chalice cells are a modification of the columnar cell. They appear to 
be formed by a conversion in shape of the columnar epithelium (ciliated or other- 
wise) consequent on the secretion, into the interior of the cell, of mucin, the chief 
organic constituent of mucus, which distends the upper part of the cell, while the 
nucleus is pressed down toward its deep part, until the cell bursts and the mucus is 
discharged on to the surface of the mucous membrane, as shown in Fig. 9. 
The spheroidal or glandular epithelium (Fig. 10) is composed of circular or 
polyhedral cells. Like other forms of epithelium cells, the protoplasm is a fine 
reticulum, which gives to the cell the appearance of granulation. They are found 
in the terminal recesses of secreting glands, and the protoplasm of the cells usually 
contains the materials which the cells secrete 
Ciliated epithelium (Fig. 11) may be of any of the preceding forms, but usually 
inclines to the columnar shape. It is distinguished by the presence of minute pro- 
cesses, which are direct prolongations of the cell-protoplasm, like hairs or eyelashes 44 
GENERAL ANATOMY. 
(cilia) standing up from the free surface. If the cells are examined during life or 
immediately on removal from the living body (for which in the human subject the 
removal of a nasal polypus offers a frequent opportunity) in tepid water, the cilia 
Fig. 10. 
Fig.11. 
Spheroidal Epithelium (magnified 
250 times). 
Ciliated Epithelium from the Human Trachea 
(magnified 350 times): a, innermost layers of 
the elastic longitudinal fibres; b, homogeneous 
innermost layers of the mucous membrane; 
c, deepest round cells; d, middle elongated; 
e, superficial, bearing cilia. 
will be seen in lashing motion; and if the cells are separate, they will often be seen 
to be moved about in the field by that motion. 
The situations in which ciliated epithelium is found in the human body are-the 
respiratory tract from the nose downward, the tympanum and Eustachian tube, the 
Fallopian tube and upper portion of the uterus, the vasa efferentia, coni vasculosi 
and first part of the excretory duct of the testicle, and the ventricles of the brain 
and central canal of the spinal cord. 
Stratified epithelium consists of several layers of cells superimposed one on 
the top of the other and varying greatly in shape. The cells of the deepest layer 
are for the most part columnar in form, and as a rule form a single layer, placed 
vertically on the supporting mem- 
brane ; above these are several 
layers of spheroidal cells, which 
as they approach the surface be- 
come more and more compressed, 
until the superficial layers are 
found to consist of flattened 
scales, the margins of which 
overlap one another so as to pre- 
sent an imbricated appearance. 
Another form of stratified epithe- 
lium is found in what has been 
termed transitional epithelium, 
such as exists in the ureters and 
urinary bladder. Here the cells 
of the most superficial layer are 
cubical, with depressions on their 
under surfaces which fit on to the 
rounded ends of the cells of the 
second layer, which are pear- 
shaped, the apices touching the 
basement - membrane. Between 
their tapering points are a third 
variety of cells, filling in the 
intervals between them, and of smaller size than those of the other two layers. 
2. Endothelium.-As before stated, endothelial cells are flattened, transparent, 
squamous cells, attached by their margins by a semifluid homogeneous cement-sub- 
Fig. 12. 
Part of Peritoneal Surface of the Central Tendon of Dia- 
phragm of Rabbit, prepared with nitrate of silver: s, sto- 
mata; I, lymph-channels; t, tendon-bundles (from Handbook 
for the Physiological Laboratory, Klein). C 0 NNE C TIVE TISS UES. 
45 
stance, so as to form a continuous endothelial membrane. Though, for the most part, 
these cells are squamous, in some places cells may be found, either isolated or occur- 
ring in patches, which are polyhedral or even columnar. These cells are frequently 
to be found lining the stomata of serous membranes, and are supposed to be endo- 
thelial cells in an active state of division (Fig. 12). As a rule, the endothelial cells 
are polygonal in outline, with sinuous or jagged margins, and are in close apposition, 
the amount of cohesive matter uniting them being so slight as not to be apparent. 
Their protoplasmic substance appears to be granular, but consists of fibrillae arranged 
in a network, in which the nucleus is contained, limited by a membrane and having 
a well-developed reticulum. 
CONNECTIVE TISSUES. 
By the term connective tissue we mean a number of tissues which possess this 
feature in common: viz. that they serve the general purpose in the animal economy 
of supporting and connecting the tissues of the frame. These tissues may differ 
considerably from each other in external appearance, but they present, nevertheless, 
many points of relationship with each other, and are moreover developed from the 
.same embryonal elements. They are divided into three great groups: (1) the 
fibrous connective tissues; (2) cartilage; and (3) bone. 
The Fibrous Connective Tissues.-Three principal forms or varieties of fibrous 
connective tissue are recognized : (1) White fibrous tissue ; (2) yellow elastic tissue; 
(3) areolar tissue. They are all composed of a matrix in which cells are imbedded, 
and between the cells are fibres of two kinds, the white and yellow or elastic. The 
difference between the three forms of tissue depends on the relative proportion of 
the two kinds of fibre, in the first variety enumerated the white fibre preponderating, 
in the second variety the yellow elastic fibres being greatly in excess of the white, 
and in the third form, areolar tissue, the two are blended in much more equal 
proportions. 
The white fibrous tissue (Fig. 13) is a true connecting structure, and serves 
three purposes in the animal economy. It serves to bind bones together in the 
form of ligaments; it serves to 
connect muscles to bones or other 
structures in the form of tendons; 
.and it forms an investing or pro- 
tecting structure to various organs 
in the form of membranes. Exam- 
ples of where it serves this latter 
office are to be found in the mus- 
cular fasciae or sheaths, the peri- 
osteum, and perichondrium; the 
investments of the various glands 
(such as the tunica albuginea tes- 
tis, the capsule of the kidney, 
etc.), the investing sheath of the nerves (perineurium) and of various organs, as 
the penis and the eye (sheath of the corpora cavernosa and corpus spongiosum and 
sclerotic). But in all these parts the student must bear in mind that the elastic 
tissue enters in greater or less proportion. It presents to the naked eye the appear- 
ance of silvery-white glistening fibres, covered over with a quantity of loose, floccu- 
lent tissue which binds the fibres together and carries the blood-vessels. It is not 
possessed of any elasticity, and has only the very slightest extensibility ; it is exceed- 
ingly strong, so that upon the application of any external violence the bone with 
which it is connected will fracture before the fibrous tissue will give way. When 
examined under the microscope it is found to consist of waving bands or bundles 
of minute, transparent, homogeneous filaments or fibrillae held together by an albu- 
minous semifluid cement-substance (Fig. 14). In ligaments and tendons these bun- 
Fig. 13. 
White Fibrous Tissue (high power). 46 
GENERAL AN A TOMY. 
dies run parallel with each other; in membranes they intersect one another in dif- 
ferent places. The bundles have a tendency to split up longitudinally or send off 
slips to join other bundles and receive others in return. The cells occurring in 
white fibrous tissue are often called M tendon-cells." They are situated on the sur- 
face of groups of bundles, and are quadrangular in shape, arranged in rows in single 
file, each cell being separated from its neighbors by a narrow line of cement-sub- 
stance. The nucleus is generally situated at one end of the cell, the nucleus of the 
Fig. 15. 
Fig. 14. 
Connective Tissue (Klein and Noble Smith): a, the 
white fibrous element - a layer of more or less 
sharply-outlined, parallel, wavy bundles of con- 
nective-tissue fibrils. On the surface of this layer 
is b, a network of fine elastic fibres. 
Tendon of Mouse's Tail, stained with logwood, show- 
ing chains of cells between the tendon-bundles 
(from Quoin's Anatomy, E. A. Schafer). 
adjoining cell being in close proximity to it (Fig. 15). Upon the addition of acetic 
acid to white fibrous tissue it swells up into a glassy-looking, indistinguishable mass. 
When boiled in water it is converted almost completely into gelatin. 
Yellow Elastic Tissue.-In certain parts of the body a tissue is found which 
when viewed in mass is of a yellowish color, and is possessed of great elasticity; so 
that it is capable of considerable extension, and when the extending force is with- 
drawn returns at once to its original condition. This is yellow elastic tissue, in 
which the elastic fibres greatly preponderate, to the almost complete exclusion of the 
white fibrous element. It is found in this condition in the ligamenta subflava, in 
the vocal cords, in the longitudinal coat of the trachea and bronchi, in the inner 
coats of the blood-vessels, especially the larger arteries, and to a very considerable 
extent in the thyro-hyoid, crico-thyroid, and stylo-hyoid ligaments. It is also found 
in the ligamentum nuchae of the lower animals. When viewed under the microscope 
(Fig. 16), it is seen to consist of an aggregation of curling fibres with a well-defined 
outline. They are considerably larger in size than the fibrillae of the white fibrous 
element, and vary much, being from the q-q to of an inch in diameter. The 
fibres form bold and wide curves, branch, and freely anastomose with each other. 
They are homogeneous in appearance, and have a tendency to curl up, especially at 
their broken ends. In some parts, where the fibres are broad and large and the 
network close, the tissue presents the appearance of a membrane, with gaps or per- 
forations corresponding to the intervening space. This is to be found in the inner 
coat of the arteries, and to it the name of fenestrated membrane has been given by 
Henle. The yellow elastic fibres remain unaltered by acetic acid. 
Areolar tissue is so called because its meshes are easily distended, and thus sep- 
arated into areolse or spaces, which all open freely into each other, and are consequently CONNECTIVE TISSUES. 
47 
easily blown up with air or permeated by fluid when injected into any part of the 
tissue. Such spaces, however, do not exist in the natural condition of the body, but 
the whole tissue forms one unbroken membrane composed of a number of interlacing 
fibres, variously superimposed. Hence the 
term "the cellular membrane" is in many 
parts of the body more appropriate than its 
more modern equivalent. The chief use of 
the areolar tissue is to bind parts together; 
while by the laxity of its fibres and the per- 
meability of its areolse it allows them to move 
on each other, and affords a ready exit for 
inflammatory and other effused fluids. It 
is one of the most extensively distributed 
of all the tissues in the body. It is found 
beneath the skin in a continuous layer all 
over the body, connecting it to the subja- 
cent parts. In the same way it is situated 
beneath the mucous and serous membrane. 
It is also found between muscles, vessels, 
and nerves, forming investing sheaths for 
them and connecting them with surround- 
ing structures. In addition to this, it is 
found in the interior of organs, binding 
together the various lobes and lobules of 
the compound glands, the various coats of 
the hollow viscera, and the fibres of mus- 
cles, etc., and thus forms one of the most 
important connecting media of the various 
structures or organs of which the body is 
made up. In many parts the areolae or in- 
terspaces of areolar tissue are occupied by 
fat-cells, constituting adipose tissue, which 
will presently be described. 
Areolar tissue presents to the naked eye 
a flocculent appearance, somewhat like spun silk. When stretched out, it is seen to 
consist of delicate soft elastic threads interlacing each other in every direction, and 
forming a network of extreme delicacy. When examined under the microscope, it 
is seen to consist of white fibres and elastic fibres intercrossing in all directions, and 
united together by a homogeneous cement or ground-substance, and filled by cellular 
elements, which contain the protoplasm 
out of which the whole is developed and 
regenerated. 
These cell-spaces may be brought 
into view by treating the tissue with 
nitrate of silver and exposing it to the 
light. This will color the fibres and 
ground-substance, leaving the cell- 
spaces unstained. 
The cells of areolar tissue (Fig- 17) 
are of two kinds: 1, flattened trans- 
parent cells, with an oblong nucleus 
and more or less branched, and often 
united together by thin-branched pro- 
cesses ; and 2, granular cells, some of 
which are of the size of white blood-corpuscles, and like them possessed of amoeboid 
movements: others are of larger size, and do not exhibit amoeboid movements to 
any appreciable extent. They lie imbedded in the ground-substance, and in some 
Fig. 16. 
Yellow Elastic Tissue (high power). 
Fig. 17. 
Connective-tissue Corpuscles (Klein and Noble Smith): 
m, migratory connective-tissue cell. The other two 
are the ordinary branched cells, each with an oblong 
nucleus. 48 
GENERAL ANATOMY. 
situations, where the areolar tissue is loose and the spaces large so as to contain 
several cells, they form a sort of lining for it. In other situations, where the tissue 
forms a membranous layer, the flattened cells, here unbranched, form an epithelial- 
like covering to its surface. 
Vessels and Nerves of Connective Tissue.-The blood-vessels of connective 
tissue are very few-that is to say, there are few actually destined for the tissue 
itself, although many vessels may permeate one of its forms, the areolar tissue, car- 
rying blood to other structures. In white fibrous tissue the blood-vessels usually 
run parallel to the longitudinal bundles and between them, sending transverse com- 
municating branches across, and in some forms, as the periosteum and dura mater, 
being fairly numerous. In the yellow elastic tissue the blood-vessels also run between 
the fibres, and do not penetrate them. Lymphatic vessels are very numerous in most 
forms of connective tissue, especially in the areolar tissue beneath the skin and the 
mucous and serous surfaces. They are also found in abundance in the sheaths of 
tendons, as well as in the tendons themselves. Nerves are to be found in the white 
fibrous tissue, where they terminate in a special manner; but it is doubtful whether 
any nerves terminate in areolar tissue; at all events, they have not yet been demon- 
strated, and the tissue is possessed of very little sensibility. 
Development of Connective Tissue.-Fibrous connective tissue is developed 
from embryonic connective-tissue cells derived from the mesoblast. At an early 
period of development it consists of nucleated cells and a muco-albuminous fluid, 
which subsequently becomes a pellucid jelly and forms the ground-substance. In 
this ground-substance the two varieties of fibres become developed. As to the 
manner in which they do so, there are two theories, some believing that they are 
•developed from the protoplasm of the cells, others that they are formed by a deposit 
in the ground-substance. In the former case the protoplasm of the cells is converted 
wholly into elementary fibres, the nucleus disappearing; or else the peripheral part 
•of the protoplasm produces the fibrous tissue, the original cell growing again to 
its original size, and then throwing off a fresh portion to form a new cell, and itself 
persisting in contact with the fibres it has formed as a permanent connective-tissue 
eorpuscle. 
Yellow elastic fibres are said by some to be formed by the processes of stellate 
embryonal cells, which, joining with processes of other cells, form the elastic fibres. 
Three special forms of connective tissue must be described: the mucoid, the 
lymphoid or retiform, and basement-membranes. 
1. The mucoid or gelatinous exists chiefly in the "jelly of Wharton," which 
forms the bulk of the umbilical cord and in some othei* 
situations in the foetus, as in the pulp of young teeth and 
in certain stages of the development of connective tissue 
in various regions. In the adult the vitreous humor of 
the eye is formed of the same material. This tissue con- 
sists of nucleated cells, which branch and become con- 
nected so as to form trabeculae, in which is contained a 
jelly-like substance containing the chemical principle of 
mucus, or mucin, and in smaller quantities albumen, but 
no gelatin. Sometimes, as in the vitreous humor of the 
eye, the cells disappear and the jelly only remains. 
2. Retiform, adenoid, or lymphoid connective tis- 
sue (Fig. 18) is found extensively in many parts of the 
body, often surrounding the minute blood-vessels and 
forming the commencement of lymphatic channels. It 
is formed of an interlacement of very fine fibres, at the 
nodal points of which stellate cells are situated. The 
interstices of the fibres are filled with the rounded gran- 
ular corpuscles of the lymph. The neuroglia, or fine 
gelatinous connective tissue which supports the nervous elements in the cerebro-spinal 
axis and in the retina, is regarded as a modified form of the retiform connective tissue. 
Fig. 18. 
•Retiform Connective Tissue, from 
the cortical part of the lymphatic 
glands. CONNECTIVE TISSUES. 
49 
3. Basement-membranes, formerly described as homogeneous membranes, are 
really a form of connective tissue. They constitute the supporting membrane, or 
membrana propria, supporting the epithelium of mucous membranes or secreting 
glands, and in other situations. By means of staining with nitrate of silver they 
may be shown to consist of flattened cells in close apposition, and form therefore an 
example of an epithelioid arrangement of connective-tissue cells. 
Adipose Tissue.-In almost all parts of the body the ordinary areolar tissue 
contains a variable quantity of adipose or fatty tissue. The principal situations 
Fig. 19. 
Adipose Tissue (high power): a, star-like appearance, from crystallization of fatty acids. 
where it is not found are the subcutaneous tissue of the eyelids, the penis and 
scrotum, the nymphse, within the cavity of the cranium, and in the lungs, except 
near their roots. Nevertheless, its distribution is not uniform, in some parts being 
collected in great abundance, as in the subcutaneous tissue, especially of the abdo- 
men, around the kidneys, on the surface of the heart between the furrows, and in 
some other situations. Lastly, fat enters largely into the formation of the marrow 
of bones. A distinction must, how- 
ever, be made between fat and adipose 
tissue, the latter being a distinct tissue 
-the former an oily matter, which in 
addition to forming adipose tissue is 
also widely present in the body, as in 
the fat of the brain and liver and in the 
blood and chyle, etc. 
Adipose tissue (Fig. 19) consists of 
a number of vesicles varying in size, 
but of about the average diameter of 
of an inch. They are formed of 
an exceedingly delicate structureless 
membrane filled with fatty matter, 
which is liquid during life, but be- 
comes solidified after death. They 
are round or spherical where they 
have not been subjected to pressure; 
otherwise they assume a more or less 
angular outline. A nucleus is always 
present, and can be easily demonstrated 
by staining with logwood ; in the natu- 
ral condition it is so compressed by the contained oily matter as to be scarcely recog - 
nizable. These fat-cells are contained in clusters in the areolar of fine connective 
Fig. 20. 
Development of Fat (Klein and Noble Smith): a, minute 
artery; v, minute vein; c, capillary blood-vessels in the 
course of formation: they are not hollowed out yet 
completely, there being still left in them protoplasmic 
septa; d, the ground-substance, containing numerous 
nucleated cells, some of which are more distinctly 
branched and flattened than others, and appear there- 
fore more spindle-shaped. 50 
GENERAL ANATOMY. 
tissue, and are held together mainly by a network of capillary blood-vessels, which 
are distributed to them. 
Fat is an inorganized substance, consisting of a liquid material (glycerin) in 
combination with certain fatty acids, stearic, palmitic, and oleic. Sometimes the 
acids separate spontaneously before the fat is examined, and are seen under the 
microscope in a crystalline form, as in Fig. 19, a. By boiling the tissue in ether or 
strong alcohol, the fat may be extracted from the vesicle, which is then seen empty 
and shrunken. 
Fat is said to be first detected in the human embryo about the fourteenth week. 
According to Klein, the fat-cells are formed by the transformation of the proto- 
plasmic connective-tissue corpuscles, into which small globules of fat find their way, 
and increase until they distend the corpuscle into the thin mantle of protoplasm which 
forms the cell-wall, and in which its nucleus is still to be seen (Fig. 20). Others of 
the connective-tissue corpuscles are transformed into the vessels and the lymphatic 
tissue which accompanies the vessels. 
PIGMENT. 
In various parts of the body pigment is found; most frequently in epitheliuni- 
cells and the cells of connective tissue. Pigmented epithelial cells are found form- 
ing the external layer of the retina (Fig. 21) and on the posterior 
surface of the iris. Pigment is also found in the epithelial cells of 
the deeper layers of the cuticle in some parts of the body, such as the 
areola of the nipple and in colored patches of skin, and especially in 
the skin of the colored races, and also in hair. It is also found in 
the epithelial cells of the olfactory regions and of the membranous 
labyrinth of the ear. 
In the connective-tissue cells pigment is frequently met with in 
the lower vertebrates. In man it is found in the choroid coat of the eye, and in 
the iris of all but the light-blue eyes and the albino. It is also occasionally met 
with in the cells of retiform tissue and in the pia mater of the upper part of the 
spinal cord. These cells are characterized by their larger size and branched pro- 
cesses, which, as well as the body of the cells, are filled with granules. The pig- 
ment consists of dark-brown or black granules of very small size, closely packed 
together within the cells, but not invading the nucleus. Occasionally the pigment 
is yellow, and when occurring in the cells of the cuticle constitutes "freckles." 
Fig. 21. 
Pigment-cells of 
Retina. 
Cartilage is a non-vascular structure which is found in various parts of the 
body-in adult life chiefly in the joints, in the parietes of the thorax, and in 
various tubes, such as the air-passages, nostrils, and ears, which are to be kept per- 
manently open. In the foetus at an early period the greater part of the skeleton is 
cartilaginous. As this cartilage is afterward replaced by bone, it is called tempo- 
rary, in contradistinction to that which remains unossified during the whole of life, 
and which is called permanent. 
Cartilage is divided, according to its minute structure, into true or hyaline car- 
tilage, fibrous or fibro-cartilage, and yellow or elastic or reticular cartilage. Besides 
these varieties met with in the adult human subject, there is a variety called cellular 
cartilage, which consists entirely, or almost entirely, of cells, united in some cases 
by a network of very fine fibres, in other cases apparently destitute of any intercel- 
lular substance. This is found in the external ear of rats, mice, and some other 
animals, and is present in the chorda dorsalis of the human embryo, but is not found 
in any other human structure. The various cartilages in the body are also classified, 
according to their function and position, into articular, interarticular, costal, and 
membraniform. 
CARTILAGE. CAR TIL A GE. 
51 
Hyaline cartilage, which may be taken as the type of this tissue, consists of a 
gristly mass of a firm consistence, but of considerable elasticity ■ and of a pearly- 
bluish color. Except where it coats the articular ends of bones it is enveloped in 
a fibrous membrane, the perichondrium, from the vessels of which it imbibes its 
nutritive fluids, being itself destitute of blood-vessels; nor have any nerves been 
traced into it. Its intimate structure 
is very simple. If a thin slice is ex- 
amined under the microscope, it will 
be found to consist of cells of a round- 
ed or bluntly angular form lying in 
groups of two or more in a granular 
or almost homogeneous matrix (Fig. 
22). The cells when arranged in 
groups of two or three have generally 
a straight outline where they are in 
contact with each other, and in the 
rest of their circumference are round- 
ed. The cell-contents consist of clear 
translucent protoplasm containing minute granules, and imbedded in this are one or 
two nuclei, having usually a granular appearance, but occasionally being clear and 
occupied by one or more nucleoli. The cells are imbedded in cavities in the matrix 
called cartilage lacunce, which are lined by a distinct transparent membrane called 
the capsule. Each lacuna is generally occupied by a single cell, but during the 
division of the cells it may contain two, four, or eight cartilage-cells. By boiling 
the cartilage for some hours and treating it with concentrated mineral acid, the cap- 
sule may be freed from the matrix, and can then be demonstrated as a distinct vesi- 
cle containing the cells. By exposure to the action of an electric shock the cell 
assumes a jagged outline and shrinks away from the interior of the capsule. 
The matrix is transparent and apparently without structure, or else presents a 
dimly granular appearance, like ground glass. According to some observers, after 
prolonged maceration bundles of fine connective-tissue fibres may be noticed in it. 
It is believed by some histologists that the matrix is permeated by a number of fine 
channels which connect the lacunae with each other, and that these canals commu- 
nicate with the lymphatics of the perichondrium, and thus the structure is permeated 
with a current of nutritious fluid. 
The articular cartilages, the temporary cartilages, and the costal cartilages are 
all of the hyaline variety. They present minute differences in the size and shape 
of their cells and in the arrangement of their matrix. In the articular cartilages, 
which show no tendency to ossification, the matrix is finely granular under a high 
power; the cells and nuclei are small and are disposed parallel to the surface in the 
superficial part, while nearer to the bone they become vertical. Articular cartilages 
have a tendency to split in a vertical direction, probably from some peculiarity in 
the intimate structure or arrangement of the component parts of the matrix. In 
disease this tendency to a fibrous splitting becomes very manifest. Articular car- 
tilage is not covered by perichondrium, at least on its free surface, where it is 
exposed to friction, though a layer of connective tissue can be traced in the adult 
over a small part of its circumference continuous with that of the synovial mem- 
brane ; and here the cartilage-cells are more or less branched, and pass insensibly 
into the branched connective-tissue corpuscles of the synovial membrane. 
Articular cartilage forms a thin incrustation upon the joint-surfaces of the bones, 
and its elasticity enables it to break the force of any concussion, whilst its smooth- 
ness affords ease and freedom of movement. It varies in thickness according to the 
shape of the bone on which it lies; where this is convex, the cartilage is thickest at 
the centre, where the greatest pressure is received; and the reverse is the case on 
the concave surfaces of the bones. Articular cartilage appears to imbibe its nutri- 
ment partly from the vessels of the neigiiboring synovial membrane, partly from 
those of the bone upon which it is implanted. Mr. Toynbee has shown that the 
Fig. 22. 
Human Cartilage-cells, from the Cricoid Cartilage (magni- 
fied 350 times). 52 
GENERAL ANATOMY. 
minute vessels of the cancellous tissue as they approach the articular lamella dilate 
and form arches, and then return into the substance of the bone. 
Temporary cartilage and the process of its ossification will be described with 
Bone. 
In the costal cartilages the cells and nuclei are large and the matrix has a tend- 
ency to fibrous striation, especially in old age (Fig. 23). These cartilages are also 
very prone to ossify. In the thickest parts 
of the costal cartilages a few large vascu- 
lar channels may be detected. This ap- 
pears at first sight an exception to the state- 
ment that cartilage is a non-vascular tissue, 
but is not so really, for the vessels give no 
branches to the cartilage-substance itself, 
and the channels may rather be looked upon 
as involutions of the perichondrium. The 
ensiform cartilage may be regarded as one 
of the costal cartilages, and the cartilages 
of the nose and of the larynx and trachea 
resemble them in microscopical characters, 
except the epiglottis and cornicula laryn- 
gis, which are of the reticular variety. The 
hyaline cartilages, especially in adult and 
advanced life, are prone to calcify; that is, 
to say, to have their matrix permeated by 
the salts of lime without any appearance 
of true bone. The process of calcification 
occurs also, and still more frequently, ac- 
cording to Rollett, in such cartilages as those of the trachea, which are prone after- 
ward to conversion into true bone. 
Fibro-cartilage consists of a mixture of white fibrous tissue and cartilaginous 
tissue in various proportions; it is to the first of these two constituents that its flex- 
ibility and toughness are chiefly owing, and to the latter its elasticity. When exam- 
ined under the microscope it is found to be made up of fibrous connective tissue 
arranged in bundles, with cartilage-cells between the bundles, which to a certain 
extent resemble tendon-cells, but 
may be distinguished from them 
by being surrounded by an in- 
vesting capsule and by their 
being less flattened (Fig. 24). 
The fibro-cartilages admit of 
arrangement into four groups- 
interarticular, connecting, cir- 
cumferential, and stratiform. 
The interarticular fibro- 
cartilages (wem'scz) are flat- 
tened fibro-cartilaginous plates, 
of a round, oval, triangular, or 
sickle-like form, interposed be- 
tween the articular cartilages of 
certain joints. They are free on 
both surfaces, thinner toward 
their centre than at their cir- 
cumference, and held in position by their margins and extremities being connected to 
the surrounding ligaments. The synovial membrane of the joint is prolonged over 
them a short distance from their attached margins. They are found in the temporo- 
maxillary, sterno-clavicular, acromio-clavicular, wrist, and knee joints. These carti- 
lages are usually found in those joints which are most exposed to violent concussion and 
Fig. 23. 
Costal Cartilage from a Man seventy-six years of age, 
showing the development of fibrous structure in.the 
matrix. In several portions of the specimen two 
or three generations of cells are seen enclosed in a 
parent cell-wall (high power). 
Fig. 24. 
White Fibrous Cartilage from the Semilunar Disk of the Patellar 
Joint of an Ox (magnified 100 times). CAR TIL A GE. 
53 
subject to frequent movement. Their use is to maintain the apposition of the opposed 
surfaces in their various motions, to increase the depth of the articular surfaces and 
give ease to the gliding movement, to moderate the effects of great pressure, and to 
deaden the intensity of the shocks to which the parts may be submitted. Professor 
Humphry has pointed out that these interarticular fibro-cartilages serve an import- 
ant purpose in increasing the variety of movements in a joint. Thus, in the knee- 
joint there are two kinds of motion-viz. angular movement and rotation-although 
it is a hinge-joint, in which, as a rule, only one variety of motion is permitted; the 
former movement taking place between the condyles of the femur and the inter- 
articular cartilage, the latter between the cartilage and the head of the tibia. So, 
also, in the temporo-maxillary j oint, the upward and downward movement of open- 
ing and shutting the mouth takes place between the cartilage and the jaw-bone, the 
grinding movement between the glenoid cavity and the cartilage, the latter moving 
with the jaw-bone. 
The connecting- fibro-cartilag-es are interposed between the bony surfaces of 
those joints which admit of only slight mobility, as between the bodies of the 
vertebrae and the pubic bones. They form disks which adhere closely to both of 
the opposed bones, and are composed of concentric rings of fibrous tissue, with 
cartilaginous laminae interposed, the former tissue predominating toward the cir- 
cumference, the latter toward the centre. 
The circumferential fibro-cartilages consist of a rim of fibro-cartilage which 
surrounds the margin of some of the articular cavities, as the cotyloid cavity of the 
hip and the glenoid cavity of the shoulder; they serve to deepen the articular sur- 
face and to protect the edges of the bone. 
The stratiform fibro-cartilages are those which form a thin layer in osseous 
grooves through which the tendons of certain muscles glide. Small masses of fibro- 
cartilages are also developed in the tendons of certain muscles where they glide over 
bones, as in the tendons of the peroneus longus and the tibialis posticus. 
The yellow, or reticular, elastic cartilage is found in the human body in the 
auricle of the external ear, the Eustachian tubes, the cornicula laryngis, and the 
epiglottis. It consists of cartilage-cells and a matrix, the latter being pervaded in 
every direction, except immediately around each cell, by a network of yellow elastic 
fibres branching and anastomos- 
ing in all directions (Fig. 25). 
The fibres resemble those of 
yellow elastic tissue, both in ap- 
pearance and in being unaffected 
by acetic acid; and according 
to Rollett their continuity with 
the elastic fibres of the neigh- 
boring tissue admits of being 
demonstrated. 
The distinguishing feature 
of cartilage as to its chemical 
composition is that it yields on 
boiling a substance called chon- 
drin, very similar to gelatin, 
but differing from it in not 
being precipitated by tannin. 
According to Kiihne, there is 
a small amount of gelatin in hyaline cartilage. Virchow believes that the semilunar 
disks in the knee-joint are wrongly denominated cartilages, since they yield no 
chondrin on boiling ; and he appears to regard them as a modification of a tendinous 
structure, which, however, agrees with the cartilages in the important particular of 
being non-vascular. 
Fig. 25. 
Yellow Cartilage, Ear of Horse (high power.) 54 
GENERAL ANATOMY. 
BONE. 
Structure and Physical Properties of Bone.-Bone is one of the hardest 
structures of the animal body; it possesses also a certain degree of toughness and 
elasticity. Its color, in a fresh state, is of a pinkish-white externally and deep red 
within. On examining a section of any bone it is seen to be composed of two kinds 
of tissue, one of which is dense and compact in texture, like ivory; the other con- 
sists of slender fibres and lamellae, which join to form a reticular structure; this, 
from its resemblance to lattice-work, is called cancellous. The compact tissue is 
always placed on the exterior of the bone; the cancellous is always internal. The 
relative quantity of these two kinds of tissue varies in different bones and in different 
parts of the same bone, as strength or lightness is requisite. Close examination of 
the compact tissue shows it to be extremely porous, so that the difference in struc- 
ture between it and the cancellous tissue depends merely upon the different amount 
of solid matter and the size and number of spaces in each, the cavities being small 
in the compact tissue and the solid matter between them abundant, while in the 
cancellous tissue the spaces are large and the solid matter in smaller quantity. 
Bone during life is permeated by vessels and is enclosed in a fibrous membrane, 
the periosteum, by means of which many of these vessels reach the hard tissue. 
If the periosteum is stripped from the surface of the living bone, small bleeding 
points are seen which mark the entrance of the periosteal vessels; and on section 
during life every part of the bone will be seen to exude blood from the minute 
vessels which ramify in it. The interior of the bones of the limbs presents a cylin- 
drical cavity filled with marrow and lined by a highly vascular areolar structure 
•Balled the medullary membrane or internal periosteum, which, however, is rather 
the areolar envelope of the cells of the marrow than a definite membrane. 
The Periosteum adheres to the surface of the bones in nearly every part, except- 
ing at their cartilaginous extremities. Where strong tendons or ligaments are attached 
to the bone the periosteum is incorporated with them. It consists of two layers 
closely united together, the outer one formed chiefly of connective tissue, containing 
occasionally a few fat-cells; the inner one, of clastic fibres of the finer kind, form- 
ing dense membranous networks, which can be again separated into several layers. 
In young bones the periosteum is thick and very vascular, and is intimately con- 
nected at either end of the bone with the epiphysial cartilage, but less closely with 
the shaft, from which it is separated by a layer of soft blastema containing a num- 
ber of granular corpuscles or "osteoblasts," in which ossification proceeds on the 
exterior of the young bone. Later in life the periosteum is thinner, less vascular, 
and the osteoblasts have become converted into an epithelial layer, which is separated 
from the rest of the periosteum in many places by cleft-like spaces, which are sup- 
posed to serve for the transmission of lymph. The periosteum serves as a nidus for 
the ramification of the vessels previous to their distribution in the bone; hence the 
liability of bone to exfoliation or necrosis when denuded of this membrane by injury 
or disease. Fine nerves and lymphatics, which generally accompany the arteries, 
may also be demonstrated in the periosteum. 
The Marrow not only fills up the cylindrical cavity in the shafts of the long 
bones, but also occupies the spaces of the cancellous tissue and extends into the 
larger bony canals (Haversian canals) which contain the blood-vessels. It differs in 
composition in different bones. In the shafts of adult long bones the marrow is of 
a yellow color, and contains, in 100 parts, 96 of fat, 1 of areolar tissue and vessels, 
and 3 of fluid, with extractive matter, and consists of a matrix of fibrous tissue sup- 
porting numerous blood-vessels and cells, most of which are fat-cells, but some few 
are "marrow-cells." In the flat and short bones, in the articular ends of the long 
bones, in the bodies of the vertebrae, in the cranial diploe, and in the sternum and 
ribs, it is of a red color, and contains, in 100 parts, 75 of water and 25 of solid 
matter, consisting of albumen, fibrin, extractive matter, salts, and a mere trace of 
fat. The red marrow consists of a small quantity of areolar tissue, blood-vessels, 
and numerous cells, some few of which are fat-cells, but the great majority roundish BONE. 
55 
nucleated cells, the true " marrow-cells " of Kolliker. These marrow-cells resemble 
in appearance the white corpuscles of the blood, and, like them, possess amoeboid 
movements. Occasionally they may be seen to possess a slightly pinkish hue, and 
it has been stated by Neumann that they are then in a transitional stage between 
marrow-cells and red blood-corpuscles, and that one of the sources of blood-globules 
is the marrow of the spongy bones. 
Griant-cells (ynyelo-plaques, osteoclasts}, large, multinucleated, protoplasmic masses, 
are also to be found in both sorts of adult marrow. 
Vessels of Bone.-The blood-vessels of bone are very numerous. Those of the 
compact tissue are derived from a close and dense network of vessels ramifying in 
the periosteum. From this membrane vessels pass into the minute orifices in the 
compact tissue, running through the canals which traverse its substance. The can- 
cellous tissue is supplied in a similar way, but by a less numerous set of larger ves- 
sels, which, perforating the outer compact tissue, are distributed to the cavities of 
the spongy portion of the bone. In the long bones numerous apertures may be seen 
at the ends near the articular surfaces, some of which give passage to the arteries 
of the larger set of vessels referred to ; but the most numerous and largest apertures 
are for the veins of the cancellous tissue, which run separately from the arteries. 
The medullary canal in the shafts of the long bones is supplied by one large artery 
(or sometimes more), which enters the bone at the nutrient foramen (situated in most 
cases near the centre of the shaft), and perforates obliquely the compact structure. 
The medullary or nutrient artery, usually accompanied by one or two veins, sends 
branches upward and downward to supply the medullary membrane which lines the 
central cavity and the adjoining canals. The ramifications of this vessel anasto- 
mose with the arteries both of the cancellous and compact tissues.1 In most of the 
flat and in many of the short spongy bones one or more large apertures are observed, 
which transmit to the central parts of the bone vessels corresponding to the medul- 
lary arteries and veins. The veins emerge from the long bones in three places 
(Kolliker): (1) by one or two large veins which accompany the artery; (2) by 
numerous large and small veins at the articular extremities; (3) by many small 
veins which arise in the compact substance. In the flat cranial bones the veins are 
large, very numerous, and run in tortuous canals in the diploic tissue, the sides of 
the canals being formed by a thin lamella of bone perforated here and there for the 
passage of branches from the adjacent cancelli. The same condition is also found 
in all cancellous tissue, the veins being enclosed and supported by osseous structure, 
and having exceedingly thin coats. When the bony structure is divided, the vessels 
remain patulous, and do not contract in the canals in which they are contained. 
Hence the constant occurrence of purulent absorption after amputation in those 
cases where the stump becomes inflamed and the cancellous tissue is infiltrated and 
bathed in pus. 
Lymphatic Vessels, in addition to those found in the periosteum, have been 
traced by Cruikshank into the substance of bone, and Klein describes them as run- 
ning in the Haversian canals. Nerves are distributed freely to the periosteum, and 
accompany the nutrient arteries into the interior of the bone. They are said by 
Kolliker to be most numerous in the articular extremities of the long bones, in the 
vertebrae, and in the larger flat bones. 
Minute Anatomy.-The intimate structure of bone, which in all essential par- 
ticulars is identical in the compact and cancellous tissue, is most easily studied in a 
transverse section from the compact wall of one of the long bones after maceration, 
such as is shown in Fig. 26. 
If this is examined with a rather low power, the bone will be seen to be map- 
1 This view is not, however, entertained by all anatomists. Mr. Charles Stuart believes that, in 
many cases at all events, the vessels of the periosteum supply only the circumferential lamellse on 
the surface of the shaft of the bone, which are formed from this membrane, and that the whole of 
the rest of its structure is supplied by the vessels of the medullary membrane, and that only very 
exceptionally does any anastomosis take place between the two sets of vessels. Certainly, in one 
microscopic section which I had an opportunity of examining through the kindness of Mr. Stuart 
this appeared to be the case. 56 
GENERAL ANATOMY. 
ped out into a number of circular districts, each one of which consists of a central 
hole surrounded by a number of concentric rings. These districts are termed Ha- 
versian systems; the central hole is an 
Haversian canal, and the rings around 
are layers of bone-tissue arranged con- 
centrically around the central canal, and 
termed lamelice. Moreover, on closer ex- 
amination it will be found that between 
these lamellae, and therefore also ar- 
ranged concentrically around the central 
canal, are a number of little dark specks, 
the lacunae, and that these lacunae are 
connected with each other and with the 
central Haversian canal by a number of 
fine dark lines which radiate like the 
spokes of a wheel, and are called canalic- 
uli. All these structures, the Haversian 
canal, the concentric lamellae, the lacunae, 
and the canaliculi, may be seen in any sin- 
gle Haversian system forming a circular 
district round a central canal. Between 
these circular systems, filling in the irreg- 
ular intervals which are left between them, 
are other lamellae, with their lacunae and 
canaliculi, running in various directions, but more or less curved (Fig. 27). These 
are termed interstitial lamellae. Again, other lamellae, for the most part found on 
the surface of the bone, are arranged concentrically to the circumference of bone, 
constituting, as it were, a single Haversian system of the whole bone, of which the 
medullary cavity would represent the Haversian canal. These latter lamellae are 
termed circumferential, or by some authors primary or fundamental, lamellae, to 
Fig. 26. 
From a Transverse Section of the Diaphysis of the 
Humerus (magnified 350 times): a, Haversian canals; 
6, lacunae, with their canaliculi in the lamellae of 
these canals; c, lacunae of the interstitial lamellae; 
d, others at the surface of the Haversian systems, 
with canaliculi going off from one side. 
Fig. 27. 
Transverse Section of Compact Tissue of Bone (magnified about 150 diameters-Sharpey). 
distinguish them from those laid down around the axis of the Haversian canals, 
which are then termed secondary or special lamellae. 
The Haversian canals, seen as round holes in a transverse section of bone at or 
about the centre of each Haversian system, may be demonstrated to be true canals 
if a longitudinal section be made, as in Fig. 29. It will then be seen that these 
round holes are tubes cut across, which run parallel with the longitudinal axis of BONE. 
57 
the bone for a short distance, and then branch and communicate. They vary con- 
siderably in size, some being as large as of an inch in diameter; the average 
size being, however, about of an inch. Near the medullary cavity the canals 
are larger than those near the surface of the bone. Each canal contains a blood- 
vessel, one or two lymphatics, and the larger ones also contain a small quantity of 
marrow. Those on the surface of the bone open by minute orifices, and those near 
the medullary cavity open in the same way into this space, so that the whole of the 
bone is permeated by a system of blood-vessels running through the bony canals in 
the centre of the Haversian systems. 
The lamelice are thin plates of bone-tissue encircling the central canal, and might 
be compared, for the sake of illustration, to a number of sheets of paper pasted one 
after another around a central hollow cylinder. After macerating a piece of bone 
in dilute mineral acid these lamellae may be stripped off in a longitudinal direction 
as thin films. If one of these is examined with a high power under the microscope, 
it will be found to be composed of a finely reticular structure, presenting the appear- 
ance of lattice-work made up of very slender, transparent fibres, decussating obliquely, 
and coalescing at the points of intersection so as to form an exceedingly delicate 
network. In many places the various lamellae may be seen to be held together by 
tapering fibres, which run obliquely through them, pinning or bolting them together. 
These fibres were first described by Sharpey, and were named by him perforating 
fibres. 
The lacunce are situated between the lamellae and consist of a number of oblong 
spaces. In an ordinary microscopic section, viewed by transmitted light, they 
appear as dark, oblong, opaque spots, and were formerly believed to be solid cells. 
Subsequently, when it was seen that the Haversian canals were channels which 
lodge the vessels of the part, and the canaliculi minute tubes by which the plasma 
Fig. 28. 
Fig. 29. 
Nucleated Bone-cells and their Processes, 
contained in the bone-lacunae and their 
canaliculi respectively (from a section 
through the vertebra of an adult mouse- 
Klein and Noble Smith). 
of the blood circulates through the tissue, it was 
taught that the lacunae were hollow spaces filled 
during life with the same fluid, and only lined 
(if lined at all) by a delicate membrane. But 
this view appears also to be delusive. Exami- 
nation of the structure of the bone when recent 
led Virchow to believe that the lacunae are really 
filled up during life with a nucleated cell, the 
processes from which pass down the canaliculi- 
a view which is now universally received (Fig. 
28). It is by means of these cells that the fluids necessary for nutrition are brought 
into contact with the ultimate tissue of bone. 
Section parallel to the surface from the Shaft 
of the Femur (magnified 100 times): a, Ha- 
versian canals; b, lacunae seen from the 
side; c, others seen from the surface in 
lamellae which are cut horizontally. 58 
GENERAL ANATOMY. 
The canaliculi are exceedingly minute channels which pass across the lamella? 
and connect the lacunae with neighboring lacunae and also with the Haversian canal. 
From this central canal a number of the canaliculi are given off, which radiate 
from it and open into the first set of lacunae arranged around the Haversian canal 
between the first and second lamellae. From these lacunae a second set of canal- 
iculi are given off, which pass outward to the next series of lacunae, and so on until 
these reach the periphery of the Haversian system; here the canaliculi given off 
from the last series of lacunae do not communicate with the lacunae of neighboring 
Haversian systems, but after passing outward for a short distance form loops and 
return to their own lacunae. Thus every part of an Haversian system is supplied 
with nutrient fluids derived from the vessels in the Haversian canals and traversing 
the canaliculi and lacunae. 
The bone-cells are contained in the lacunae, which, however, they do not com- 
pletely fill. They are flattened nucleated cells, which Virchow has shown are homol- 
ogous with those of connective tissue. The cells are branched, and the branches, 
especially in young bones, pass with the canaliculi from the lacunae. 
If a longitudinal section be examined, as in Fig. 29, the appearances are iden- 
tical. The appearance of concentric rings is replaced by that of lamellae or rows 
of lacunae parallel to the course of the Haversian canals, and these canals appear 
like half-tubes instead of circular spaces. The tubes are seen to branch and 
communicate, so that each separate Haversian canal runs only a short distance. 
In other respects the structure has much the same appearance as in transverse 
sections. 
In sections of thin plates of bone (as in the walls of the cells which form the 
cancellous tissue) the Haversian canals are absent and the canaliculi open into the 
spaces of the cancellous tissue (medullary spaces), which thus have the same func- 
tions as the Haversian canals in the more compact bone. 
Chemical Composition.-Bone consists of an animal and an earthy part 
intimately connected together. 
The animal part of a bone may be obtained by immersing the bone for a consid- 
erable time in dilute mineral acid, after which process the bone comes out exactly the 
same shape as before, but perfectly flexible, so that a long bone (one of the ribs, for 
example) can easily be tied 
in.a knot (Fig. 30). If now a 
transverse section be made 
(Fig. 31), the same general 
arrangement of the Haver- 
sian canals, lamellae, lacu- 
nae, and canaliculi is seen, 
though not so plainly as in 
the ordinary section. 
The earthy part may be 
obtained separate by cal ci' 
nation, by which the ani- 
mal mater is completely 
burnt out. The bone will still retain its original form, but it will 
be white and brittle, will have lost about one-third of its original 
weight, and will crumble down with the slightest force. The 
earthy matter confers on bone its hardness and rigidity, and the 
animal matter its tenacity. 
The animal base is often called cartilage, but differs from it in 
structure, in the fact that it is softer and more flexible, and that 
when boiled with a high pressure it is almost entirely resolved into 
gelatin. 
The organic constituent of bone forms about one-third, or 33.3 
per cent.; the inorganic matter, two-thirds, or 66.7 per cent.; as 
is seen in the subjoined analysis of Berzelius: 
[Fig. 30. 
Fig. 31. 
Section of Bone after the removal of the earthy 
matter by the action of acids. 
Fibula tied in a 
knot after ma- 
ceration in a di- 
lute acid (from 
a specimen pre- 
served in spirits). 
(Dalton).] BONE. 
59 
Organic matter 
Inorganic 
or 
Earthy matter 
Gelatin and blood-vessels 33.30 
Phosphate of lime 51.04 
Carbonate of lime . . . 11.30 
Fluoride of calcium 2.00 
Phosphate of magnesia 1.16 
Soda and chloride of sodium 1.20 
100.00 
Some chemists add to this about 1 per cent, of fat. 
Some difference exists in the proportion between the two constituents of bone at 
different periods of life. In the child the animal matter predominates, whereas in 
aged people the bones contain a larger proportion of earthy matter, and the animal 
matter is deficient in quantity and quality. Hence in children it is not uncommon 
to find, after an injury to the bones, that they become bent or only partially broken, 
whereas in old people the bones are more brittle and fracture takes place more 
readily. Some of the diseases also to which bones are liable mainly depend on the 
disproportion between the two constituents of bone. Thus in the disease called 
rickets, so common in the children of the poor, the bones become bent and curved, 
either from the superincumbent weight of the body or under the action of certain 
muscles. This depends upon some defect of nutrition by which bone becomes 
deprived of its normal proportion of earthy matter, whilst the animal matter is of 
unhealthy quality. In the vertebrae of a rickety subject Dr. Bostock found in 100 
parts 79.75 animal and 20.25 earthy matter. 
Development of Bone 
In the foetal skeleton some bones, 
such as the long bones of the limbs, 
are cartilaginous; others, as the cra- 
nial bones, are membranous. Hence 
two kinds of ossification are describ- 
ed : the intracartilaginous and the' 
intramembranous ; and to these a 
third is sometimes added, the sub- 
periosteal, which, however, is the 
same as the second, only taking- 
place under different circumstances. 
Intracartilaginous Ossifica- 
tion.-Just before ossification be- 
gins the bone is entirely cartilagi- 
nous, and in a long bone, which 
may be taken as an example, the 
process commences in the centre 
and proceeds toward the extrem- 
ities, which for some time remain 
cartilaginous. Subsequently a sim- 
ilar process commences in one or 
more places in those extremities, 
and gradually extends through it. 
The extremity does not, however, 
become joined to the shaft of the 
bone until growth has ceased, but 
remains separated by a layer of 
cartilaginous tissue termed epiphys- 
ial cartilage. 
The first step in the ossification 
of the cartilage is that the carti- 
lage-cells, at the point where ossi- 
fication is commencing, and which 
Fig. 32. 
Longitudinal Section through the Ossifying Portion of a Long 
Bone in the Human Embryo: a, cartilaginous region; b, 
region of calcified matrix. 60 
GENERAL AN AT 0 Al Y. 
is termed a centre of ossification, enlarge and arrange themselves in rows (Fig. 32). 
The matrix in which they are imbedded increases in quantity, so that the cells become 
further separated from each other. A deposit of calcareous material now takes place 
in this matrix between the rows of cells, so that they now become separated from 
each other by longitudinal columns of calcified matrix, presenting a granular and 
opaque appearance. Here and there the matrix between two cells of the same row 
also becomes calcified, and thus we have transverse bars of calcified substance stretch- 
ing across from one calcareous column to another. Thus we have longitudinal groups 
of the cartilage-cells enclosed in oblong cavities the walls of which are formed of 
calcified matrix. These cavities are called the primary areolce (Sharpey). 
At the same time that this process is going on in the centre of the cartilage of 
which the foetal bone consists, certain changes are taking place on its surface. This 
is covered by a very vascular membrane, the periosteum, on the inner surface of 
which-that is to say, on the surface in contact with the cartilage-are a number 
of cells called osteoblasts. By the agency of these cells a thin layer of bony tissue 
Fig. 33. 
Fig. 34 
Part of a Longitudinal Section of the Devel- 
oping Femur of a Rabbit: a, flattened car- 
tilage-cells ; b, enlarged cartilage-cells; c, d, 
newly-formed bone; e, osteoblasts ; f, giant- 
cells or osteoblasts; g, h, shrunken carti- 
lage-cells (from Atlas of Histology, Klein 
and Noble Smith). 
Section of Foetal Bone of Cat: ir, irruption of the sub- 
periosteal tissue; p, fibrous layer of the periosteum; o, 
layer of osteoblasts; im, subperiosteal bony deposit; 
bl, blood-vessels occupied by blood-corpuscles (from 
Quoin's Anatomy, E. A. Schafer). 
is being formed between the periosteum and the cartilage by the intramembranous 
mode of ossification presently to be described. We have, then, in this first stage 
of ossification, two processes going on simultaneously: in the centre of the carti- BONE 
61 
lage the formation of a number of oblong spaces formed of calcified matrix and 
containing the cartilage-cells enlarged and arranged in groups, and on the surface 
of the cartilage the formation of a layer of true membrane-bone. The second stage 
consists in the prolongation into the cartilage of processes of the deeper or osteo- 
genetic layer of the periosteum. The processes consist of blood-vessels and cells 
(osteoblasts). They excavate passages through the new-formed bony layer by 
absorption, and pass through it into the calcified matrix (Fig. 33). Wherever these 
processes come in contact with the calcified walls of the primary areolae they absorb 
it, and thus cause a fusion of the original cavities and the formation of larger spaces, 
which are termed the secondary areolce (Sharpey) or medrdlary spaces (Muller). In 
these secondary spaces the original cartilage-cells disappear, and their cavities become 
filled with embryonic marrow, consisting of osteoblasts and vessels, and derived, at 
all events in part, in the manner described above from the osteogenetic layer of the 
periosteum. What becomes of the cartilage-cells is not finally determined. By most 
histologists they are believed to be con- 
verted, after division, into osteoblasts, 
and so assist in forming the embryonic 
marrow. Others, on the other hand, 
believe that they are simply absorbed 
and take no part in the formation of 
bone. 
Thus far, then, we have got enlarged 
spaces (secondary areolae), the walls of 
which are still formed by calcified carti- 
lage-matrix, containing an embryonic 
Fig. 36. 
Fig. 35. 
Vertical Section from the Edge of the Ossifying Por- 
tion of the Diaphysis of a Metatarsal Bone from a 
Foetal Calf (after Muller): a, ground mass of the 
cartilage; b, of the bone; c, newly-formed bone- 
cells in profile, more or less imbedded in intercell- 
ular substance; d, medullary canal in process of 
formation, with vessels and medullary cells ; e, f, 
bone-cells on their broad aspect; g, cartilage-cap- 
sules arranged in rows, and partly with shrunken 
cell-bodies. 
Transverse Section from the Femur of a Human Em- 
bryo about eleven weeks old: a, medullary sinus 
cut transversely, and b, another longitudinally; c, 
osteoblasts; d, newly-formed osseous substance of 
a lighter color; e, that of greater age; f, lacunae with 
their cells; g, a cell still united to an osteoblast. 
marrow, derived from the processes sent in from the osteogenetic layer of the perios- 
teum, and consisting of blood-vessels and round cells, osteoblasts (Fig. 34), some of 
which probably are derived from the division of the original cartilage-cells, which 
have disappeared. The walls of these secondary areolae are at this time of only incon- 
siderable thickness, but they now become thickened by the deposition of layers of new 62 
GENERAL ANATOMY. 
bone on their interior. This process takes place in the following manner : Some of 
the osteoblasts of the embryonic marrow, after undergoing rapid division, arrange 
themselves as an epithelioid layer on the surface of the wall of the space (Fig. 35). 
This layer of osteoblast forms a bony stratum, and thus the wall of the space becomes 
gradually covered with a layer of true osseous substance. On this a second layer 
of osteoblasts arrange themselves, and in their turn form an osseous layer. By the 
repetition of this process the original cavity becomes very much reduced in size, and 
at last only remains as a small circular hole in the centre, containing the remains of 
the embryonic marrow ; that is, a blood-vessel and a few osteoblasts. This small cavity 
constitutes the Haversian canal of the perfectly ossified bone. The successive layers of 
osseous matter which have been laid down and which encircle this central canal con- 
stitute the lamellae of which, as we have seen, each Haversian system is made up. As 
the successive layers of osteoblasts form osseous tissue, certain of the osteoblastic cells 
remain included between the various bony layers. These continue persistent and 
remain as the corpuscles of the future bone, the spaces enclosing them forming the 
lacunae (Fig. 36). The mode of the formation of the canaliculi is not known. 
Such are the changes which may be observed at one particular point, the centre 
of ossification. While they have been going on here, a similar process has been 
proceeding in the same manner toward the end of the shaft, so that in the ossifying 
bone all the changes described above may be seen in different parts, from the true 
bone in the centre of the shaft to the hyaline cartilage at the extremities. The bone 
thus formed differs from the bone of the adult in being more spongy and less reg- 
ularly lamellated. 
Thus far, then, we have followed the steps of a process by which a solid bony 
mass is produced having vessels running into it from the periosteum, Haversian 
canals in which those vessels run, medullary spaces filled with foetal marrow, lacunae 
with their contained bone-cells, and canaliculi growing out of these lacunae. 
This process of ossification, however, is not the origin of the whole of the skeleton, 
for even in those bones in which the ossification proceeds in a great measure from a 
single centre situated in the cartilaginous shaft of a long bone, a considerable part 
of the original bone is formed by intramembranous ossification beneath the peri- 
chondrium or periosteum ; so that the girth of the bone is increased by bony deposit 
from the deeper layer of this membrane. The shaft of the bone is at first solid, but 
a tube is hollowed out in it by absorption around the vessels passing into it, which 
becomes the medullary canal. This absorption is supposed to be brought about by 
large "giant-cells," which have long been recognized as a constituent of foetal mar- 
row, and which are believed by Kblliker to have the power of absorbing or dissolv- 
ing bone; and he has therefore named them "osteoclasts." They vary in shape 
and size, and are known by containing a large number of clear nuclei, sometimes as 
many as twenty. The occurrence of similar cells in some tumors of bones has led 
to such tumors being denominated "myeloid." 
As more and more bone is removed by this process of absorption from the interior 
of the bone to form the medullary canal, so more and more bone is deposited on the 
exterior from the periosteum, until at length the bone has attained the shape and 
size which it is destined to retain during adult life. As the ossification of the car- 
tilaginous shaft extends toward the articular ends, it carries with it, as it were, a 
layer of cartilage, or the cartilage grows as it ossifies, and thus the bone is increased 
in length. During this period of growth the articular end, or epiphysis, remains 
for some time entirely cartilaginous; then a bony centre appears in it, and it com- 
mences the same process of intracartilaginous ossification; but this process never 
extends to any great distance. The epiphyses remain separated from the shaft by a 
narrow cartilaginous layer for a definite time. This layer ultimately ossifies, the 
distinction between shaft and epiphysis is obliterated, and the bone assumes its com- 
pleted form and shape. The same remarks also apply to the processes of bone which 
are separately ossified, such as the trochanters of the femur. The bones, having 
been formed, continue to grow until the body has acquired its full stature. They 
increase in length by ossification continuing to extend in the epiphysial cartilage, BONE. 
63 
which goes on growing in advance of the ossifying process. They increase in cir- 
cumference by deposition of new bone from the deeper layer of the periosteum on 
their external surface, and at the same time an absorption takes place from within 
by which the medullary cavity is increased. 
The medullary spaces which characterize the cancellous tissue are produced by 
the absorption of the original foetal bone in the same way as the original medullary 
canal is formed. The distinction between the cancellous and compact tissue appears 
to depend essentially upon the extent to which this process of absorption has been 
carried; and we may perhaps remind the reader that in morbid states of the bone 
inflammatory absorption produces exactly the same change, and converts portions of 
bone naturally compact into cancellous tissue. 
Intramembranous Ossification.-The intramembranous ossification is that by 
which the bones of the vertex of the skull are entirely formed. In the bones which 
are so developed no cartilaginous mould precedes the appearance of the bone-tissue. 
In the membrane which occupies the place of the future bone a little network of 
bony spiculae is first noticed radiating from the point of ossification. When these 
rays of growing bone are examined by the microscope, they are found to consist of 
a network of fine clear fibres and granular corpuscles, with a ground-substance 
between. The fibres are termed osteogenic fibres, and soon become dark and gran- 
ular from calcification, and as they calcify 
they are found to enclose the granular cor- 
puscles or "osteoblasts" (Fig. 37). The 
calcification not only involves the osteogenic 
fibres, but also the ground-substance of the 
tissue in which they are contained. The 
corpuscles at first lie upon the osteogenic 
fibres, so that they can be removed by brush- 
ing the specimen with a hair-pencil in order 
to render the fibres clear; but they gradually 
become involved in the ossifying matrix and 
form the corpuscles of the future bone, the 
spaces in which they are enclosed constitut- 
ing the lacunae. As the tissue increases in 
thickness vessels shoot into it, grooving for 
themselves spaces or channels which become 
the Haversian canals. Thus, the intramem- 
branous and intracartilaginous processes of 
ossification are similar in their more essential features. 
The number of ossific centres is different in different bones. In most of the 
short bones ossification commences by a single point in the centre, and proceeds 
toward the circumference. In the long bones there is a central point of ossification 
for the shaft or diaphysis, and one or more for each extremity, the epiphysis. That 
for the shaft is first to appear. The union of the epiphyses with the shaft takes 
place in the reverse order to that in which their ossification began, and appears to 
be regulated by the direction of the nutrient artery of the bone. Thus, the nutri- 
ent arteries of the bones of the arm and forearm are directed toward the elbow, and 
the epiphyses of the bones forming this joint become united to the shaft before 
those at the opposite extremity. In the lower limb, on the other hand, the nutrient 
arteries pass in a direction from the knee; that is, upward in the femur, downward 
in the tibia and fibula; and in them it is observed that the upper epiphysis of the 
femur and the lower epiphysis of the tibia and fibula become first united to the 
shaft. 
Where there is only one epiphysis, the medullary artery is directed toward 
that end of the bone where there is no additional centre, as toward the acromial 
end of the clavicle, toward the distal end of the metacarpal bone of the thumb 
and great toe, and toward the proximal end of the other metacarpal and metatarsal 
bones. 
Fig. 37. 
Osteoblasts from the Parietal Bone of a Human Em- 
bryo thirteen weeks old (after Gegenbauer): a, 
bony septa with the cells of the lacunee; b, layers 
of osteoblasts; c, the latter in transition to bone- 
corpuscles. GENERAL ANATOMY. 
64 
Besides these epiphyses for the articular ends, there are others for projecting 
parts or processes which are formed separately from the bulk of the bone. For an 
account of these the reader must be referred to the description of the individual 
bones in the sequel. 
A knowledge of the exact periods when the epiphyses become joined to the shaft 
is often of great importance in medico-legal injuries. It also aids the surgeon in 
the diagnosis of many of the injuries to which the joints are liable; for it not infre- 
quently happens that on the application of severe force to a joint the epiphysis 
becomes separated from the shaft, and such injuries may be mistaken for fracture 
or dislocation. 
MUSCULAR TISSUE. 
The Muscles are formed of bundles of reddish fibres endowed with the property 
of contractility. Two kinds of muscular tissue are found in the animal body-viz. 
that of voluntary or animal life, and that of involuntary or organic life. The mus- 
cles of animal life (striped muscles) are capable of being put in action and controlled 
by the will. They are composed of bundles of fibres enclosed in a delicate web 
called the internal perimysium, in contradistinction to the sheath of areolar tissue 
which invests the entire muscle, the external perimysium. The bundles are termed 
fasciculi; they are prismatic in shape, of different sizes in different muscles, and 
for the most part placed parallel to one another, though 
they have a tendency to converge toward their tendin- 
ous attachments. Each fasciculus is made up of a 
bundle of fibres, which also run parallel with each 
other, and which are separated from one another by a 
delicate connective tissue derived from the perimysium, 
and termed endomysium (Fig. 38). 
A muscular fibre may be said to consist of a soft 
contractile substance enclosed in a tubular sheath, 
named by Bowman the sarcolemma. The fibres are 
cylindrical or prismatic in shape, and are of no great 
length, not extending, it is said, farther than an inch 
and a half. They end either by blending with the 
tendon or aponeurosis, or else by becoming drawn out 
into a tapering extremity which is connected to the 
neighboring fibre by means of the sarcolemma. Their 
breadth varies in man from -g-i-g- to of an inch, the 
average of the majority being about As a rule, 
the fibres do not divide or anastomose; but occasionally, especially in the tongue 
and facial muscles, the fibres may be seen to divide into several branches. The 
precise mode in which the muscular fibre joins the tendon has been variously 
described by different observers. It may, perhaps, be sufficient here to say that the 
sarcolemma, or membranous investment of the muscular fibre, appears to become 
blended with the tissue of the tendon and prolonged more or less into the tendon, 
so that the latter forms a kind of sheath around the fibre for a longer or shorter 
distance. When muscular fibres are attached to the skin or mucous membranes their 
fibres are described by Hyde Salter as becoming continuous with those of the areolar 
tissue. 
The sarcolemma or tubular sheath of the fibre is a transparent, elastic, and 
apparently homogeneous membrane of considerable toughness, so that it will some- 
times remain entire when the included substance is ruptured. (See Fig. 39.) On 
the internal surface of the sarcolemma in Mammalia, and also in the substance of 
the fibre in the lower animals, elongated nuclei are seen (Fig. 56), and in connec- 
tion with these a row of granules, apparently fatty, is sometimes observed. Upon 
examination of a muscular fibre by transmitted light under a sufficiently high power, 
it is found to be apparently marked by alternate light and dark bands or striae, 
Fig. 38. 
Transverse Section from the Sterno- 
mastoid in Man (magnified 50 
times): a, external perimysium; 
6, fasciculus; c, internal perimys- 
ium ; d, fibre. MUSCULAR TISSUE. 
65 
which pass transversely or somewhat obliquely round the fibre (Fig. 39). The dark 
and light bands are of nearly equal breadth, and alternate with great regularity. 
They vary in breadth from about the y-yy o' to the yy-j-y of an inch. Other stride 
pass longitudinally over the fibres, though they are less distinct than the former. 
This longitudinal striation gives the fibre the appearance of being made up of a 
bundle of fibrillae. The muscular fibre can be broken up either in a longitudinal 
or transverse direction (Fig. 40). If hardened in alcohol it can be broken up lon- 
gitudinally, and forms the so-called fibrillae of which some suppose the fibre to be 
Fig. 39. 
Fig. 40. 
Fragments of Striped Elementary Fibres, showing a cleavage in 
opposite directions (magnified 300 diameters): A, longitudinal 
cleavage. The longitudinal and transverse lines are both seen. 
Some longitudinal lines are darker and wider than the rest, and 
are not continuous from end to end. This results from partial 
separation of the fibrillse. c, fibrillee separated from one another 
by violence at the broken end of the fibre, and marked by trans- 
verse lines equal in width to those on the fibre; c' c" represent 
two appearances commonly presented by the separated single 
fibrillae (more highly magnified); at c' the borders and transverse 
lines are all perfectly rectilinear, and the included spaces per- 
fectly rectangular; at c" the borders are scalloped and the spaces 
bead-like. When most distinct and definite the fibrilla presents 
the former of these appearances. 
B, transverse cleavage : the longitudinal lines are scarcely visible. 
a, incomplete fracture following the opposite surfaces of a disk 
which stretches across the interval and retains the two frag- 
ments in connection. The edge and surfaces of this disk are 
seen to be minutely granular, the granules corresponding in 
size to the thickness of the disk and to the distance between 
the faint longitudinal lines; b, another disk nearly detached; 
b', detached disk, more highly magnified, showing the sarcous 
elements. 
Two Human Muscular Fibres (magni- 
fied 350 times): In the one, the bun- 
dle of fibrillae (6) is torn, and the 
sarcolemma (a) is seen as an empty 
tube. 
made up. Each fibril is marked by transverse striae, and appears to consist of a 
single row of minute quadrangular particles, named "sarcous elements" by Bow- 
man. A still further division, however, is capable of being made, and each of 
these fibrillae may be divided into minute threads (Fig. 41, B, cZ), consisting of an 
alternate dark and light spot. After exposure to the action of dilute hydrochloric 
acid, the muscular fibre can be broken transversely (Fig. 40, b). It then forms 
disks or plates consisting of the same quadrangular particles, attached by their lat- 
eral surfaces. 
Upon closer examination with a very high power the appearances become more 
complicated, and are susceptible of various interpretations. The transverse stria- 
tion, which in Figs. 39 and 40 appears as a mere alternation of dark and light 
bands, is resolved into the appearance shown in Fig. 41, which shows a series of 
broad dark bands separated by a light band, which is itself divided into two by a 
dark streak. This streak is termed Krause's membrane; it is continuous at each 
end with the sarcolemma investing the muscular fibre. Thus it may be said that 
the fibre is divided into a number of transverse compartments by this membrane, 
each compartment containing in the centre a dark plate with a bright border above 
and below-that is to say, between the dark central part and the membrane of 
Krause. This appearance is explained by some as depending on some optical prop- 
erty of the investment of the separate sarcous elements. Thus it is supposed that 
the sarcous elements have an opaque interior, and are united to each other by a 
transparent envelope or cell-membrane, the sides of which cohere so closely as only 66 
GENERAL ANATOMY. 
to show a single line, while their ends are united by some different material which 
breaks up the light and causes a dark band or row of dark dots in the centre of the 
transparent streak formed by the cohesion of the two cell-membranes. Mr. Schafer 
describes the sarcous elements as formed by an aggregation of rod-like masses of 
protoplasm, having rounded, ends, and believes that the two bright bands and inter- 
vening row of dark dots are the result of the diffraction of the light around these 
rounded ends, "just as a minute oil-globule in water appears surrounded with a 
bright halo when examined under the microscope." Krause describes the structure 
of striped muscle somewhat differently. The dark line which separates the two 
transparent disks seen in Fig. 32 between the rows of sarcous elements is a trans- 
parent homogeneous membrane, the membrane of Krause, continuous with the sar- 
Fig. 41. 
Fig. 42. 
Part of a Striped Muscular Fibre of Hydrophy- 
lus, prepared with absolute alcohol (magni- 
fied 300 diameters-Klein and Noble Smith): 
a, sarcolemma; b, membrane of Krause: 
owing to contraction during hardening the 
sarcolemma shows regular bulgings. At the 
side of Krause's membrane is the transparent 
lateral disk. The chief mass of a " muscle- 
compartment" is occupied by the contractile 
disk composed of sarcous elements. 
Several nuclei of muscle-corpuscles are shown, 
and in them a minute network. 
A, portion of a Medium-sized Human Muscular Fibre (mag- 
nified nearly 800 diameters). 
B, separated Bundles of Fibrils, equally magnified: a, a, 
larger, and b, b, smaller collections ; c, still smaller; d, d, 
the smallest which could be detached. 
colemma (Fig. 42). The transparent band on either side of this membrane (trans- 
parent lateral disk) separates on either side the sarcous elements from the membrane 
of Krause. The whole space comprised between two adjacent membranes of Krause 
and the corresponding sarcolemma is called a muscle-compartment. Within these 
compartments is contained the muscular substance, consisting of a central, dim, 
doubly-refracting disk, which occupies the greater portion of the compartment, but 
is separated above and below from Krause's membrane by a thin layer of transpa- 
rent, homogeneous fluid-substance which is singly refracting. The central doubly- 
refracting portion is the true contractile substance, and appears to be homogeneous, 
but in reality is made up of a numbei' of rod-shaped elements. This gives the 
appearance of longitudinal striation, after post-mortem changes have taken place, 
which is not visible during life. In the centre of this contractile substance a 
transparent lighter band can sometimes be discerned; this is known as the median 
disk of Hensen. 
This form of muscular fibre composes the whole of the voluntary muscles, all the 
muscles of the ear, those of the larynx, pharynx, tongue, the upper half of the 
oesophagus, the heart, and the walls of the large veins at the point where they open 
into it. The fibres of the heart, however, differ very remarkably from those of 
other striped muscles. They are smaller by one-third, and their transverse striae 
are by no means so distinct. The fibres are made up of distinct quadrangular cells MUSCULAR TISSUE. 
67 
joined end to end (Fig. 43). Each cell contains a clear oval nucleus situated near 
the centre of the cell. The extremities of the cells have a tendency to branch or 
divide, the subdivisions uniting with offsets from other cells, and thus producing an 
anastomosis of the fibres (Fig. 43). The connective tissue between the bundles of 
fibres is much less than in ordinary striped muscle, and no sarcolemma has been 
proved to exist. 
The capillaries of striped muscle are very abundant and form a sort of rectangular 
network, the branches of which run longitudinally 
between the muscular fibres, and are joined at short 
intervals by transverse anastomosing branches. 
Nerves are profusely distributed to striped muscle. 
The mode of their termination will be described on a 
subsequent page. 
The existence of lymphatic vessels in striped mus- 
cle has not been ascertained, though they have been 
found in tendons and in the sheath of the muscle. 
The unstriped, muscle, or muscle of organic 
life, is found in the walls of the hollow viscera-viz. 
the lower half of the oesophagus and the whole of the 
remainder of the gastro-intestinal tube; in the trachea 
and bronchi; in the gall-bladder and ductus com- 
munis choledochus; in the pelvis and calices of the 
kidney, the uterus, bladder, and urethra; in the female 
sexual organs-viz. the Fallopian tubes, the uterus 
(enormously developed in pregnancy), the vagina, the 
broad ligaments, and the erectile tissue of the clitoris ; 
in the male sexual organs-viz. the dartos scroti, the 
vas deferens and epididymis, the vesiculae seminales, 
the prostate gland, and the corpora cavernosa; in the 
ducts of certain glands, as in Wharton's duct; in the capsule and trabeculse of the 
spleen; in the mucous membranes forming the muscularis mucosae; in the arteries, 
veins, and lymphatics; in the iris ; and in the skin. 
Plain or unstriped muscular fibre is made up of spindle-shaped cells called con- 
tractile fibre-cells, collected into bundles and held together by a cement-substance in 
which are contained some connective-tissue corpuscles (Fig. 44). These bundles are 
further aggregated into larger bundles or flattened bands, and bound together by 
ordinary areolar tissue. 
The contractile fibre-cells (Fig. 45) are elongated, spindle-shaped, nucleated cells 
of various lengths, averaging from to of an inch in length and to 
yglg-p of an inch in breadth. On transverse section they are more or less polyhedral 
in shape from mutual pressure. They present a distinctly longitudinally striated 
appearance, and consist of an elastic cell-wall containing a central bundle of fibrillae 
representing the contractile substance, and an oval or rod-like nucleus, which includes, 
within a membrane, a fine network communicating at the poles of the nucleus with 
the contractile fibres (Klein). The adhesive interstitial substance which connects 
the fibre-cells together represents the endomysium, or delicate connective tissue which 
binds the fibres of striped muscular tissue into fasciculi, while the tissue connecting 
the individual bundles together represents the perimysium. The unstriped muscle, 
as a rule, is not under the control of the will, nor is the contraction rapid and 
involving the whole muscle, as is the case with the muscles of animal life. The 
membranes which are composed of the unstriped muscle slowly contract in a part 
of their extent, generally under the influence of a mechanical stimulus, as that of 
distension or of cold; and then the contracted part slowly relaxes while another 
portion of the membrane takes up the contraction. This peculiarity of action is 
most strongly marked in the intestines, constituting their vermicular motion. 
Chemical Composition of Muscle.-In chemical composition the musculai 
fibres of both forms consist mainly of a proteid substance-myosin-which Dr. M. 
Fig. 43. 
Anastomosing Muscular Fibres of the 
Heart, seen in a longitudinal sec- 
tion. On the right the limits of the 
separate cells with their nuclei are 
exhibited somewhat diagrammat- 
ically. 68 
GENERAL ANATOMY. 
Foster speaks of as intermediate between fibrin and globulin. It is readily con- 
verted by the action of dilute acids into syntonin or acid-albumen, and by the action 
of dilute alkalies into alkali-albumen. Muscle which is neutral or slightly alkaline 
Fig. 44. 
Fig. 45. 
Non-striated Elementary Fibres from the 
Human Colon: a, treated with acetic 
acid, showing the corpuscles; b, frag- 
ment of a detached fibre not touched 
with acid. 
Muscular Fibre-cells from Human Arteries: 1, 
from the popliteal artery; a, without; b, with 
acetic acid. 2, from a branch of the anterior 
tibial ; a, nuclei of the fibres (magnified 350 
times). 
in reaction when at rest is rendered acid by contraction, from the development 
probably of sarcolactic acid. After death muscle also exhibits an acid reaction, 
but this appears to be due to post-mortem change. 
NERVOUS TISSUE. 
The nervous tissues of the body are comprised in two great systems-the 
eerebro-spinal and the sympathetic ; and each of these systems consists of a central 
organ, or series of central organs, and of nerves. 
The cerebrospinal system comprises the brain (including the medulla oblongata), 
the spinal cord, the cranial nerves, the spinal nerves, and the ganglia connected with 
both these classes of nerves. The sympathetic system consists of a double chain of 
ganglia, with the nerves which go to and come from them. It is not directly con- 
nected with the brain or spinal cord, though it is so indirectly by means of its 
numerous communications with the cranial and spinal nerves. 
All these nervous tissues are composed chiefly of two different structures-the 
gray or vesicular, and the white or fibrous. It is in the former, as is generally sup- 
posed, that nervous impressions and impulses originate, and by the latter that they 
are conducted. Hence the gray matter forms the essential constituent of all the 
ganglionic centres, both those separated in the ganglia and those aggregated in the 
cerebro-spinal axis; while the white matter is found in all the commissural portions 
of the nerve-centres and in all the cerebro-spinal nerves. The nerves of the sym- 
pathetic system are chiefly composed of a somewhat different material in structure, 
which is named gray or gelatinous nerve-fibre. This form of nerve-fibre is also 
found in some of the cerebro-spinal nerves. 
The gray or vesicular nervous substance is distinguished by its dark reddish- 
gray color and soft consistence. It is found in the brain, spinal cord, and various 
ganglia intermingled with the fibrous nervous substance, and also in some of the NERVOUS TISSUE. 
69 
nerves of special sense, and in gangliform enlargements which are found here and 
there in the course of certain cerebro-spinal nerves. It is composed, as its name 
implies, of vesicles or corpuscles, commonly called nerve- or ganglion-corpuscles, 
containing nuclei and nucleoli: the vesicles are imbedded either in a finely gran- 
ular substance destitute of any nucleated sheath, as in the brain, or else contained 
in a hyaline capsule lined by a more or less continuous layer of nucleated endothe- 
lial cells, as in the ganglia. Each vesicle consists of a finely granular protoplasmic 
material, of a reddish or yellowish-brown color, which occasionally presents patches of 
a deeper tint caused by the aggregation of pigment-granules (Fig. 46). No distinct 
limiting membrane or cell-wall has been ascertained to exist. The nucleus is, as a rule, 
a large, well-defined, round, vesicular body, often presenting an intranuclear net- 
work, and containing a nucleolus which is peculiarly clear and brilliant. The nerve- 
corpuscles vary in shape and size; some are small, spherical or ovoid, with a general 
Fig. 47. 
Fig. 46. 
Nerve-vesicles fiom the Gasserian Gang- 
lion of the Human Subject: a, a globular 
one with defined border; b, its nucleus; 
c, its nucleolus; d, caudate vesicle; e, 
elongated vesicle with two groups of 
pigment-particles; f, vesicle surrounded 
by its sheath or capsule of nucleated par- 
ticles ; g, the same, the sheath only being 
in focus (magnified 300 diameters). 
Nerve-vesicles from the inner part of the Gray Matter of 
the Convolutions of the Human Brain (magnified 350 
times): Nerve-cells-a, larger; b, smaller; c, nerve-fibre 
with axis-cylinder. 
even outline, such as those frequently found in the spinal ganglia; others are more 
or less angular, as in the ganglia of the sympathetic; others, again, are caudate or 
stellate in shape, and are characterized by their large size and by their having one 
or more tail-like processes issuing from them, which occasionally divide and subdi- 
vide into numerous branches (Fig. 47). These are found in greatest number in the 
gray matter of the spinal cord. Still others are flask-shaped, as in the cortex of the 
cerebellum, or conical, as in the cerebral convolutions. For the most part, nerve- 
cells have one or more processes, and they are distinguished by the number of these 
processes, as unipolar, bipolar, or multipolar cells. These processes are very deli- 
cate, apparently tubular, and contain a similar granular material to that found 
within the corpuscle. Some of the processes terminate in fine transparent fibres, 
which become lost among the other elements of the nervous tissue; others may be 
traced until, after losing their granular appearance, they become continuous with an 
ordinary nerve-fibre. 
The white or fibrous nerve-substance or nerve-fibre is found universally in the 
nervous cords, and also constitutes a great part of the brain and spinal cord. The 
fibres of which it consists are of two kinds-the medullated or white fibres, and the 
non-medullated or gray fibres. 
The medullated [or dark-bordered] fibres form the white part of the brain 
and spinal cord, and also the greater part of the cerebro-spinal nerves, and give to 70 
GENERAL ANATOMY. 
these structures their opaque white aspect. When perfectly fresh they appear to be 
homogeneous; but soon after removal from the body they present, when examined 
by transmitted light, a double outline or contour, as if consisting of two parts. The 
central portion is named the axis-cylinder of Purkinje; around this is a sort of 
sheath of fatty material named the white substance of Schwann, which gives to the 
fibre its double contour, and the whole is enclosed 
in a delicate membrane, the neurilemma1 or primi- 
tive sheath (Fig. 48). 
The axis-cylinder (Fig. 49) constitutes about one- 
half or one-third of the nerve-tube, the white sub- 
stance being greater in proportion in the nerves 
than in the central organs. It 
is perfectly transparent, and 
is therefore indistinguishable 
in a perfectly fresh and nat- 
ural state of the nerve. It 
is described by Kblliker as 
being distinguished from the 
white substance by the fact 
that, though soft and flex- 
ible, it is not fluid and vis- 
cid, but firm and elastic, 
somewhat like coagulated 
albumen, with which it appears for the most part 
also to agree in its chemical characters. When 
examined under a high power it presents the 
appearance of a longitudinal striation, as if com- 
posed of very fine homogeneous fibrillae held to- 
gether in a faintly granular interstitial material. 
Occasionally at its termination the axis-cylinder 
of a fibre may be seen to break up into exceedingly fine fibrillae, confirming the 
view of its fibrillar structure. These fibrillae have been 
termed the primitive fibrillce of Schultze. The axis- 
cylinder is said to be enveloped in a very delicate hya- 
line sheath which separates it from the white matter of 
Schwann. 
The medullary sheath or white matter of Schwann 
is regarded as being a fatty matter in a fluid state, 
which insulates and protects the essential part of the 
nerve-the axis-cylinder. The white matter varies in 
thickness to a very considerable extent, in some form- 
ing a layer of extreme thinness, so as to be scarcely dis- 
tinguishable ; in others forming about one-half the nerve- 
tube. The size of the nerve-fibres, which varies from 
to 2 (/o o an inch, depends mainly upon the 
amount of the white substance, though the axis-cylin- 
der also varies in size within certain limits. The 
white substance of Schwann does not always form a 
continuous sheath to the axis-cylinder, but undergoes 
interruptions in its continuity at regular intervals, 
giving to the fibre the appearance of constriction at 
these points. These were first described by Ranvier, 
and are known as the nodes of Ranvier (Fig. 50). 
The portion of nerve-fibre between two nodes is called 
an internodal segment. The neurilemma or primitive 
Fig. 48. 
[Fig. 49. 
Diagram of Structure of 
Medullated Nerve-fibre: 
1, neurilemma or sheath 
of Schwann; 2, medullary 
sheath; 3, axis-cylinder.] 
Human Nerve-tubes (magnified 350 
times). Three of them are fine, one 
of which is varicose, one of middling 
thickness, and with a single contour, 
and three thick, two of which are 
double-contoured, and one with 
grumous contents. 
[Fig. 50. 
Nerve-fibre from Sciatic Nerve of 
Rabbit, after action of nitrate of 
silver: a, ring formed by thicken- 
ed membrane of Schwann (node of 
Ranvier); m, white substance of 
Schwann rendered transparent by 
glycerin; cy, cylinder-axis, which 
just above and below the level of 
the annular constriction presents 
the lines of Frommann.] 
1 In older histological works the term "neurilemma" is used to designate the fibrous envelope 
of the whole nerve, now called " perineurium." NERVOUS TISSUE. 
71 
sheath is not interrupted at the nodes, but passes over them as a continuous mem- 
brane. Each internodal segment contains an oval nucleus imbedded in the medullary 
sheath, and occasionally more than one nucleus may be seen in the same internode. 
Medullated nerve-fibres, when examined, frequently present a beaded or varicose 
appearance: this is due to manipulation and pressure causing the oily matter to col- 
lect into drops, and in consequence of the extreme delicacy of the primitive sheath 
even slight pressure will cause the transudation of the fatty matter, which collects as 
drops of oil outside the membrane. This is, of course, promoted by the action of 
ether (Fig. 51). 
The neurilemma or primitive sheath (sometimes called the tubular membrane or 
nucleated sheath of Schwann) at first appears structureless, but when stained with 
nitrate of silver is seen to consist of nucleated endothelial cells. The nuclei of these 
cells are oval and somewhat flattened, and bear a definite relation to the nodes of 
Ranvier, one nucleus generally 
lying in the centre of each node, 
though in some few instances two 
nuclei may be found in the same 
node. 
Non-Medullated Fibres.- 
Most of the nerves of the sym- 
pathetic system, and some of the 
cerebro-spinal (see especially the 
description of the olfactory nerve), 
consist of another variety of ner- 
vous fibres, which are called the 
gray or gelatinous nerve-fibres- 
fibres of Remak (Fig. 52). These 
consist of a bundle of finely-stri- 
ated fibrillae enclosed in a sheath. 
Nuclei may be detected at inter- 
vals in each fibre, which Schultze 
believes to be situated in the sheath 
of the nerve-fibre, as in the medul- 
lated variety. In external appear- 
once the gelatinous nerves are semi-transparent and gray 
or yellowish-gray. The individual fibres vary in size, 
generally averaging about half the size of the medullated 
fibres; but, on the one hand, the primitive fibrillae formed 
by breaking up of the cerebro-spinal fibres, as above men- 
tioned, are of hardly appreciable thickness, while, on the other hand, some of the 
gelatinous fibres (especially those on the olfactory bulb) are said to be three or four 
times as thick as those of the cerebro-spinal nerves. 
Chemical Composition.-The different portions of the nervous system are com- 
posed of the two above-described kinds of nervous structure, the chemical composi- 
tion of which is shown by the following analysis by Lassaigne, which represents the 
relative proportion of the different constituents composing the gray and white mat- 
ter of the brain: 
Fig. 51. 
7, 
Fig. 52. 
a, Nerve-tube of the Common 
Eel in Water. The delicate 
line on its exterior indicates 
the tubular membrane. The 
dark double-edged inner 
one is the white substance 
of Schwann, slightly wrink- 
led; b, the same in ether. 
Several oil-globules have 
coalesced in the interior, 
and others have accumu- 
lated around the exterior 
of the tube. The white sub- 
stance has in part disap- 
peared (magnified 300 diam- 
eters). 
A Small Nervous Branch from 
.the Sympathetic of a Mam- 
mal : a, two dark-bordered 
nerve-tubes among a num- 
ber of Remak's fibres, b. 
Water 
Gray. 
85.2 
White. 
73.0 
Albuminous matter 
7.5 
9.9 
Colorless fat 
1.0 
13.9 
Red fat 
3.7 
0.9 
Osmazome and lactates 
1.4 
1.0 
Phosphates 
1.2 
1.3 
It appears from this analysis that the cerebral substance consists of albumen dis- 
solved in water, combined with fatty matter and salts. The fatty matters consist of 
cerebrin, neurin, and lecithin. The two latter were first described by Liebreich as 
a crystalline phosphuretted fat, which he termed protagon. It seems probable, how- 72 
GENERAL ANATOMY. 
ever, that it is simply a mixture of neurin and lecithin. Cholesterin is also described 
as one of the chemical constituents of the nervous tissues, being found in conjunction 
with lecithin. The salts are the phosphates of potash, soda, lime, magnesia, and 
iron, sulphate of potash and chloride of sodium, with traces of silica. According to 
Vanquelin, the cord contains a larger proportion of fat than the brain; and accord- 
ing to the nerves contain more albumen and more soft fat than the brain. 
The nervous structures are divided, as before mentioned, into two great systems 
-viz. the cerebrospinal, comprising the brain and spinal cord, the nerves connected 
with these structures, and the ganglia situated on them ; and the sympathetic, con- 
sisting of a double chain of ganglia and the nerves connected with them. All these 
structures require separate consideration; they are composed of the two kinds of 
nervous tissue above described, intermingled in various proportions, and having, in 
some parts, a very intricate arrangement. 
The Brain, or Encephalon, is that part of the cerebro-spinal system which is 
contained in the cavity of the skull. It is divided into several parts, named the 
medulla oblongata, pons, cerebellum, and cerebrum. In these parts the gray or 
vesicular nervous matter is found partly on the surface of the brain, forming the 
convolutions of the cerebrum, which are in the most direct relation to the mental 
faculties, and the laminae of the cerebellum, the functions of which are still a matter 
of dispute. Again, gray matter is found in the interior of the brain, collected into 
large and distinct masses or ganglionic bodies, such as the corpus striatum, optic 
thalamus, and corpora quadrigemina; the functions of which bodies, so far as they 
have been ascertained, have been found to be connected with some of the main 
organic endowments of the body, such as voluntary motion, sensation, and sight. 
Finally, gray matter is found intermingled intimately with the white, but without 
definite arrangement, as in the corpora dentata of the medulla and cerebellum, or 
the gray matter in the pons and the floor of the fourth ventricle. Such scattered 
masses of gray matter are-in many instances, at any rate-connected, to all appear- 
ance, with the origin of particular nerves. In some situations their use is unknown. 
The proper nervous matter, both in the brain and spinal cord, is traversed and 
supported by a network of fine connective tissue. This has been termed by Virchow 
the neuroglia, and is supposed to be the source of one of the forms of the tumor 
described by that author under the name glioma. 
The white matter of the brain is divisible into three distinct classes of fibres. 
These are, in the first place, the nerves which arise in the gray matter and pass out 
through the cranial foramina. Next, the fibres which connect the brain with the 
spinal cord; that is to say, those which are usually traced upward from the columns 
of the spinal cord, through the medulla oblongata, into the encephalon, chiefly by 
means of the anterior pyramids, fasciculi teretes, and restiform bodies, passing 
through the pons and crura cerebri to expand into the corpora striata, optic thala- 
mus, and convolutions {corona radiatd), and by means of the restiform bodies into 
the cerebellum. The other class of white fibres in the brain are commissural, some 
of the commissures serving to connect different parts of the same hemisphere together 
(as the fornix, processus e cerebello ad testes, etc.) or even different parts of the same 
section or organ, as the arciform fibres of the medulla. Most of these commissures 
are longitudinal, while others, as the corpus callosum and the transverse fibres of 
the pons Varolii, are transverse, serving to connect opposite hemispheres together, 
and thus probably securing the single action of a double organ. 
The manner in which the gray and white matter are intermingled in the brain 
and spinal cord is very intricate, and can only be fully understood by a careful study 
of the details of its descriptive anatomy in the sequel. The further consideration 
of this subject will therefore be deferred until after the description of the various 
divisions of which the cerebro-spinal system is made up. 
The Nerves are round or flattened cords formed of the nerve-fibres already 
described. They are connected at one end with the cerebro-spinal centre or with 
the ganglia, and are distributed at the other end to the various textures of the 
body; they are subdivided into two great classes-the cerebrospinal, which proceed NERVOUS TISSUE. 
73 
from the cerebro-spinal axis, and the sympathetic or ganglionic nerves, which pro- 
ceed from the ganglia of the sympathetic. 
The Cerebro-spinal nerves consist of numerous nerve-fibres collected together 
and enclosed in a membranous sheath (Fig. 53). A small bundle of primitive 
fibres enclosed in a tubular sheath is called a, funiculus ; if the nerve is of small 
size, it may consist only of a single 
funiculus, but if large, the funiculi are 
collected together into larger bundles or 
fasciculi, which are bound together in a 
common membranous investment, and 
constitute the nerve. 
In structure the common membranous 
investment, or sheath of the whole nerve, 
which is called the epineurium, as well as 
the septa given off from it, and which sep- 
arate the fasciculi, consists of areolar tis- 
sue, composed of white and yellow elastic 
fibres, the latter existing in great abun- 
dance. The tubular sheath of the funic- 
uli, called the neurilemma or perineur- 
ium, consists of a fine, smooth, trans- 
parent membrane, which may be easily 
separated, in the form of a tube, from 
the fibres it encloses; in structure it 
consists of connective tissue, which has 
a distinctly lamellar arrangement, con- 
sisting of several lamellae, separated 
from each other by spaces containing 
lymph. The cerebro-spinal nerves con- 
sist almost exclusively of the medullated 
nerve-fibres, the non-medullated existing 
in very small proportions. 
The blood-vessels supplying a nerve 
terminate in a minute capillary plexus, the vessels composing which run, for the 
most part, parallel with the funiculi; they are connected together by short trans- 
verse vessels forming narrow oblong meshes, similar to the capillary system of 
muscle. 
The nerve-fibres, as far as is at present known, do not coalesce, but pursue an 
uninterrupted course from the centre to the periphery. In separating a nerve, how- 
ever, into its component funiculi, it may be seen that they do not pursue a perfectly 
insulated course, but occasionally join at a very acute angle with other funiculi pro- 
ceeding in the same direction; from this branches are given off, to join again in like 
manner with other funiculi. It must be remembered, however, that in these com- 
munications the nerve-fibres do not coalesce, but merely pass into the sheath of the 
adjacent nerve, become intermixed with its nerve-fibres, and again pass on, to become 
blended with the nerve-fibres in some adjoining funiculus. 
Nerves, in their course, subdivide into branches, an 1 these frequently communi- 
cate with branches of a neighboring nerve. In the subdivision of a nerve, the fila- 
ments of which it is composed are continued from the trunk into the branches, and 
at their junction with the branches of neighboring nerves the filaments pass to 
become intermixed with those of the other nerves in their further progress; in no 
instance, however, have the separate nerve-fibres been shown to inosculate. The 
communications which take place between two or more nerves form what is called a 
plexus. 
Sometimes a plexus is formed by the primary branches of the trunks of the nerves 
-as the cervical, brachial, lumbar, and sacral plexuses-and occasionally by the ter- 
minal funiculi, as in the plexuses formed at the periphery of the body. In the forma- 
Fig. 53. 
Transverse Section through a Microscopic Nerve, repre- 
senting a compound nerve-bundle, surrounded by 
perineurium (magnified 120 diameters). The medul- 
lated fibres are seen as circles with a central dot-viz. 
medullary sheath and axis-cylinder in transverse sec- 
tion. They are imbedded in endoneurium contain- 
ing numerous nuclei, which belongs to the connective- 
tissue ceils of the latter (Klein and Noble Smith): p, 
perineurium, consisting of laminse of fibrous connec- 
tive tissues, alternating with flattened nucleated con- 
nective-tissue cells; I, lymph-space between perineur- 
ium and surface of nerve-bundle. 74 
GENERAL ANATOMY. 
tion of a plexus the component nerves divide, then join, and again subdivide in such 
a complex manner that the individual funiculi become interlaced most intricately, so 
that each branch leaving a plexus may contain filaments from each of the primary 
nervous trunks which form it. In the formation also of smaller plexuses at the 
periphery of the body there is a free interchange of the funiculi and primitive fibres. 
In each case, however, the individual filaments remain separate and distinct, and do 
not inosculate with one another. 
It is probable that through this interchange of fibres the different branches pass- 
ing off from a plexus have a more extensive connection with the spinal cord than if 
they each had proceeded to be distributed without such connection with other -nerves. 
Consequently, the parts supplied by these nerves have more extended relations with 
the nervous centres; by this means, also, groups of muscles may be associated for 
combined action. 
The Sympathetic nerves are constructed in the same manner as the cerebro- 
spinal nerves, but consist mainly of non-medullated fibres collected into funiculi 
and enclosed in a sheath of connective tissue. There is, however, in these nerves a cer- 
tain admixture of medullated fibres, the amount of which varies in different nerves. 
They may be known by their color. Those branches of the sympathetic which present 
a well-marked gray color are composed more especially of gelatinous nerve-fibres, 
intermixed with a few medullated fibres, whilst those of a white color contain more 
of the latter fibres and a few of the former. Occasionally, the gray and white cords 
run together in a single nerve, without any intermixture, as in the branches of com- 
munication between the sympathetic ganglia and the spinal nerves or in the commu- 
nicating cords between the ganglia. 
The nerve-fibres, both of the cerebro-spinal and sympathetic system, convey 
impressions of a twofold kind. The sensory nerves, called also centripetal or 
afferent nerves, transmit to the nervous centres impressions made upon the periph- 
eral extremities of the nerves, and in this way the mind, through the medium of 
the brain, becomes conscious of external objects. The motor nerves, called also 
centrifugal or efferent nerves, transmit impressions from the nervous centres to the 
parts to which the nerves are distributed, these impressions either exciting muscular 
contraction or influencing the processes of nutrition, growth, and secretion. 
Origin and Termination of Nerves.-By the expression " the termination of 
nerve-fibres " is signified their connections with the nerve-centres and with the parts 
they supply. The former are sometimes called their origin or central termination, 
the latter their peripheral termination. The origin in some cases is single; that is 
to say, the whole nerve emerges from the nervous centre by a single root; in other 
instances the nerve arises by two or more roots, which come off from different parts 
of the nerve-centre, sometimes widely apart from each other; and it often happens 
that when a nerve arises in this way by two roots the functions of these two roots 
are different; as, for example, in the spinal nerves, each of which arises by two 
roots, the anterior of which is motor, and the posterior sensory. The point where 
the nerve-root or roots emerge from the nervous centre is named the superficial or 
apparent origin, but the fibres of which the nerve consists can be traced for a cer- 
tain distance into the nervous centre to some portion of the gray substance, which 
constitutes the deep or real origin of the nerve. The exact manner in which the 
fibres of which the nerve-root is made up arise at their deep origin is, to a certain 
extent, uncertain. But it would appear probable that there are two modes in which 
they originate and are connected with the nerve-cells. If the multipolar nerve-cells 
are examined, it will be found that one at least of their processes does not branch ; 
this process is named the axial-cylinder process, and at first has all the characters 
of an axis-cylinder. Soon, however, it acquires a medullary sheath, and has been 
traced to be directly continuous with a nerve-fibre.' Other processes of a multipolar 
cell divide and subdivide as they pass away from the cell, until at last they form 
branches of extreme tenuity and form an excessively minute network. These pro- 
cesses apparently consist of cell-protoplasm, and are named protoplasm processes. 
From the network which they form minute medullated nerve-fibres arise. So that NERVOUS TISSUE. 
75 
it would appear that nerve-fibres arise-first, directly through the passage of the 
non-branched axis-cylinder process into a fibre; and secondly, through the minute 
network formed by the branched protoplasm processes. 
Peripheral Terminations of Nerves.-The manner in which nerve-fibres ter- 
minate peripherally are several, and may be conveniently studied in the sensory and 
motor nerves respectively. Sensory nerves would appear to terminate either in 
minute primitive fibrillae or networks of these, or else in special terminal organs, 
which have been termed peripheral end-organs, and of which there are three prin- 
cipal varieties-viz. the end-bulbs of Krause, the tactile corpuscles of Wagner, and 
the Pacinian corpuscles. 
When a medullated nerve-fibre approaches its termination the white substance 
of Schwann suddenly disappears, leaving only the axis-cylinder surrounded by the 
neurilemma, and we have now a non-medullated fibre. This undergoes repeated 
division, and after a time loses its neurilemma, and consists only of an axis-cylin- 
der, which can be seen, in preparations stained with chloride of gold, to be made 
up of fine varicose fibrils. Finally, the axis-cylinder breaks up its constituent 
primitive nerve-fibrillae, which anastomose with one another, thus forming a net- 
work, and often present regular varicosities. This network passes between the 
elements of the tissue to which the nerves are distributed, and, as is believed by 
some, actually forms a connection with the cells of the tissue or else simply comes 
in contact with them. In this way nerve-fibres have been found to terminate in 
the epithelium of the skin and mucous membranes and in the anterior epithelium 
of the cornea. 
The End-bulbs of Krause are minute oblong or cylindrical corpuscles, into the 
interior of which the axis-cylinder of the nerve-fibre passes and terminates in a 
coiled plexiform mass or in a bulbous extremity. The corpuscle consists of a simple 
nucleated capsule containing a soft homogeneous core, in which the termination of 
the axis-cylinder is contained. The white matter of Schwann ceases abruptly as 
the axis-cylinder enters the corpuscle, but the neurilemma is continued inward with 
the axis-cylinder, and forms an investment of the core, lining the interior of the 
capsule. The end-bulbs have been described as occurring in the conjunctivae 
(where, in man, they are spheroidal in shape), in the mucous membrane of the 
mouth, and in the cutis and mucous membrane of the penis, clitoris, and vagina, 
where they are termed genital corpuscles. 
The Tactile Corpuscles of Wagner (Fig. 54) are described by him as oval- 
shaped bodies made up of a soft structureless core, in which the nerve-fibres termi- 
nate by bulbous enlargements, the whole being enclosed in a capsule of connective 
tissue, so arranged in superimposed laminae as to present a resemblance to a minia- 
ture fir-cone; and he regarded them as directly concerned in the sense of touch. 
Kblliker considers that the central part of the papillae generally consists of a con- 
nective tissue more homogeneous than that of the outer part, surrounded by a sort 
of sheath of elastic fibres ; and he believes that these corpuscles are merely a variety 
of this structure. The nerve-fibres, according to this observer, run up in a waving 
course to the corpuscle, not penetrating it, but forming two or three coils round it, 
and finally join together in loops. It would appear, however, that the medullated fibre 
winds round the corpuscle once or twice, and then loses its medullary sheath and 
penetrates as an axis-cylinder into the interior of the corpuscle, and there branches, 
the branches pursuing a coiled direction within the capsule and terminating in bulb- 
ous enlargements. These tactile corpuscles have been described as occurring in the 
papillae of the skin of the fingers and toes. They are not found in all the papillae; 
but from their existence in those parts in which the skin is highly sensitive it is 
probable that they are specially concerned in the sense of touch, though their 
absence from the papillae of other tactile parts shows that they are not essential to 
this sense. 
The Pacinian Corpuscles1 (Fig. 55) are found in the human subject chiefly on 
the nerves of the fingers and toes, lying in the subcutaneous tissue; but they have 
1 Often called in German anatomical works "corpuscles of Vater." 76 
GENERAL ANATOMY. 
also been described as connected with the nerves of the joints, in the genital organs 
of man, and in some other situations. Each of these corpuscles is attached to and 
encloses the termination of a single nerve-fibre. The corpuscle, which is perfectly 
visible to the naked eye (and which can be most easily demonstrated in the mesen- 
tery of a cat), consists of a number of concentric layers of cellular tissue, between 
which Todd and Bowman have figured capillary vessels as running. The tissue of 
each lamella is lax, and the interstices between its fibres are filled by a considerable 
quantity of watery fluid ; it is covered on each surface by a layer of epithelioid cells. 
The nerve at its entrance into this body parts with its white substance, and the axis- 
cylinder runs forward into a kind of cavity in the centre of the corpuscle containing 
a core of homogeneous material, to termi- 
nate in a rounded knob or end, sometimes 
bifurcating previously, in which case each 
branch has a similar arrangement. Gran- 
dry, who has examined these corpuscles with 
very high magnifying powers, describes the 
axis-cylinder as exhibiting a very well- 
marked fibrillar structure, and the bulbous 
end as consisting of a mass of granules into 
which the fibrils run, diverging as they ap- 
proach it. The investing capsules are from 
thirty to sixty in number, the outer being 
Fig. 55. 
A Fig. 54. 
From the Human Subject, treated with acetic acid (mag- 
nified 350 times): A, side view of a papilla of the hand; 
a, cortical layer; b, tactile corpuscle, with transverse 
nuclei; c, small nerve of the papilla, with neurilemma; 
d, its two nervous fibres running with spiral coils around 
the tactile corpuscle; e, apparent termination of one of 
these fibres. 
E, a tactile papilla seen from above, so as to show its 
transverse section; a, cortical layer; b, nerve-fibre; c, 
outer layer of the tactile body, with nuclei; d, clear 
interior substance. 
Pacinian Corpuscle, with its system of capsules 
and central cavity: a, arterial twig, ending 
in capillaries, which form loops in some of 
the intercapsular spaces, and one penetrates 
to the central capsule; b, the fibrous tissue 
of the stalk prolonged from the perineur- 
ium ; n, nerve-tube advancing to the cen- 
tral capsule, there losing its white substance, 
and stretching along the axis to the opposite 
end, where it is fixed by a tubercular enlarge- 
ment. 
more or less separated from each other by a clear fluid-lymph-while the inner 
are more closely applied together. Schultze calls attention to the striking resem- 
blance between the central part or core of these Pacinian corpuscles and Krause's 
end-bulbs above described. 
In the organs of special sense the nerves terminate in cells which are modified 
epithelium-cells, and have received the name of sensory or nerve-epithelium cells. 
The axis-cylinder, after dividing into fibrils, ends in epithelium-cells variously mod- 
ified, and to the peripheral extremity of which are often connected peculiar styliform 
processes. These cells will be more particularly described in the sequel, in connec- 
tion with the description of the organs of special sense. 
Motor nerves are to be traced either into unstriped or striped muscular fibres. 
In the unstriped or involuntary muscles the nerves are derived from the sympa- 
thetic, and are composed mainly of the non-medullated fibres. Near their termina- NERVOUS TISSUE. 
77 
tions they divide into a number of branches, which communicate and form an inti- 
mate plexus. At the junction of the branches small nuclear bodies are situated. 
From these plexuses minute branches are given off, which divide and break up into 
the ultimate fibrillae of which the nerve is composed. These fibrillae course between 
the involuntary muscle-cells, and, according to Elischer, terminate on the surface of 
the cell, opposite the nucleus, in a minute swelling. Arnold and Frankenhauser 
believed that these ultimate fibrillae penetrated the muscular cell and ended in the 
nucleus. More recent observation has, however, tended to disprove this. 
In the striped or voluntary muscle the nerves supplying striped muscular fibre 
are derived from the cerebro-spinal nerves, and are composed mainly of medullated 
fibres. The nerve, after entering the sheath of the muscle, breaks up into fibres or 
bundles of fibres which form plexuses, and gradually divide until, as a rule, a single 
nerve-fibre enters a single muscular fibre. Sometimes, however, if the muscular 
fibre is long, more than one nerve-fibre enters it. Within the muscular fibre the 
nerve terminates in a special expansion, called by Kuhne, who first accurately 
Fig. 56. 
Muscular Fibres of Lacerta viridis, with the terminations of nerves: a, seen in profile ; p, p, the nerve-end plates , 
s, s, the base of the plate, consisting of a granular mass with nuclei; b, the same, as seen in looking at a per- 
fectly fresh fibre, the nervous ends being probably still excitable. (The forms of the variously divided plate 
can hardly be represented in a woodcut oy sufficiently delicate and pale contours to reproduce correctly what 
is seen in nature.) c, the same as seen two hours after death from poisoning by curare. 
described them, motorial end-plates (Fig. 56).1 The nerve-fibre on approaching the 
muscular fibre suddenly loses its white matter of Schwann, which abruptly termi- 
nates ; the nucleated sheath becomes continuous with the sarcolemma of the muscle, 
and only the axis-cylinder enters the muscular fibre, where it immediately spreads 
out, ramifying like the roots of a tree, immediately beneath the sarcolemma, and is 
imbedded in a layer of granular matter containing a number of clear oblong nuclei, 
the whole constituting an end-plate from which the contractile wave of the muscular 
fibre is said to start. 
The Ganglia may be regarded as separate and independent nervous centres, of 
.smaller size and less complex structure than the brain, connected with each other, 
with the cerebro-spinal axis, and with the nerves in various situations. They are 
found on the posterior root of each of the spinal nenes, on the posterior or sensory 
root of the fifth cranial nerve, on the facial nerve, on the glosso-pharyngeal and 
pneumogastric nerves, and on the branches of certain spinal nerves. They are also 
found in a connected series along each side of the vertebral column, forming the 
trunk of the sympathetic, and on the branches of that nerve, generally in the 
plexuses or at the point of junction of two or more nerves with each other or with 
branches of the cerebro-spinal system. On section they are seen to consist of a 
reddish-gray substance traversed by numerous white nerve-fibres; they vary con- 
' They had, however, previously been noticed, though not accurately described, by Doyere, who 
Jiamed them " nerve-hillocks." 78 
G EN ER ALA NA T 0 M Y. 
siderably in form and size; the largest are found in the cavity of the abdomen; the 
smallest, not visible to the naked eye, exist in considerable numbers upon the nerves 
distributed to the different viscera. The ganglia are invested by a smooth and firm, 
closely-adhering, membranous envelope consisting of dense areolar tissue; this 
sheath is continuous with the perineurium of the nerves, and sends numerous pro- 
cesses into the interior of the ganglion, which support the blood-vessels supplying 
its substance. 
In structure all ganglia are essentially similar (Fig. 57), consisting of the same 
structural elements as the other nervous 
centres-viz. a collection of vesicular ner- 
vous matter traversed by tubular and 
gelatinous nerve-fibres. The vesicular 
nervous matter consists of nerve- or 
ganglion-cells, most of which appear to 
be free and of a round or oval form ; 
these are more especially seated near the 
surface of the ganglion; others are uni- 
polar, bipolar, or multipolar, and their 
caudate processes give origin to nerve- 
fibres. In the ganglion the nerve-cells 
are usually enclosed in a transparent cap- 
sule with nuclei on its inner surface. The 
nerve-fibres on entering the ganglion lay 
aside their perineurium, which becomes 
continuous with the capsule. Some of 
the fibres run through the ganglion with- 
out being connected with the cells, others 
arise from the caudate processes of the 
cells. 
A' remarkable modification of the 
bipolar nerve-cell is found in the sym- 
pathetic ganglia, especially in the frog, 
but also in some few instances in the 
mammal. The cells are pear-shaped, 
and from the narrow end two processes 
arise-one a straight axis-cylinder process, into which the substance of the ganglion 
is prolonged; the other, a thin fibre, winds spirally round the straight fibre, and 
then passes away from the cell in the opposite direction, and becomes invested with 
-a medullary sheath and neurilemma of its own, and constitutes a medullated fibre, 
while the straight axis-cylinder process forms a non-medullated fibre. 
Fig. 57. 
Section through a Microscopic Ganglion (magnified 300 
diameters-Klein and Noble Smith): c, capsule of the 
ganglion; n, nerve-fibres passing out of the ganglion. 
The nerve-fibres which entered the ganglion are not 
represented. The nerve-fibres are ordinary medul- 
lated fibres, but the details of their structure are not 
shown, owing to the low magnifying power. The 
ganglion-cells are invested by a special capsule lined 
by a few nuclei, which are here represented as if con- 
tained in the capsule. 
The Vascular System, exclusive of its central organ, the heart, is divided into 
four classes of vessels: the arteries, capillaries, veins, and lymphatics; the minute 
structure of which we will now proceed briefly to describe, referring the reader to the 
body of the work for all that is necessary in the details of their ordinary anatomy. 
Structure of Arteries (Fig. 58).-The arteries are composed of three coats: 
internal or endothelial coat (tunica intima of Kblliker) ; middle [muscular and elas- 
tic] circular coat [twnwa media}; and external cellular coat, or tunica adventitia. 
The two inner coats together are very easily separated from the external, as by 
the ordinary operation of tying a ligature on an artery. If a fine string be tied for- 
cibly upon an artery and then taken off, the external coat will be found undivided, 
but the internal coats are divided in the track of the ligature, and can easily be 
further dissected from the outer coat. The inner coat can be separated from the 
middle by a little maceration, or it may be stripped off in small pieces; but on 
THE VASCULAR SYSTEM. THE VASCULAR SYSTEM. 
79 
account of its friability it cannot be separated as a complete membrane. It is a fine, 
transparent, colorless structure which is highly elastic, and is commonly corrugated 
into longitudinal wrinkles. 
The inner coat [tumca intima] consists of-1. A layer of pavement-epithelium, the 
the cells of which are polygonal, oval, or fusi- 
form, and have very distinct round or oval 
nuclei. This endothelium, as it is now gen- 
erally called, is brought into view most dis- 
tinctly by staining with nitrate of silver. 2. 
A subepithelial layer, consisting of delicate 
connective tissue with branched cells lying in 
the interspaces of the tissue. 3. An elastic 
or fenestrated layer, which consists of an elas- 
tic membrane containing a network of elastic 
fibres, having principally a longitudinal direc- 
tion, and in which, under the microscope, 
small elongated apertures or perforations 
may be seen, giving it a fenestrated ap- 
pearance. It was therefore called by Henle 
the fenestrated membrane. This membrane 
forms the chief thickness of the inner coat, 
and can be separated into several layers, some 
of which present the appearance of a network 
of longitudinal elastic fibres, and others pres- 
ent a more membranous character, marked by 
pale lines having a longitudinal direction. In 
arteries of less than a line in diameter the 
subepithelial layer consists of a single layer 
of stellate cells, and the connective tissue is 
only largely developed in the large-sized ves- 
sels. The fenestrated membrane in micro- 
scopic arteries is a very thin layer, but in the 
larger arteries, and especially in the aorta, it 
has a very considerable thickness. 
The middle coat (tunica media] is distin- 
guished from the inner by its color and by 
the transverse [z. e. circular] arrangement of 
its fibres, in contradistinction to the longi- 
tudinal direction of those of the inner coat. [It consists of two elements, the elastic 
and the muscular. The elastic predominates largely in the aorta and its branches. 
These are distended by the blood forced into them by the systole of the heart, and 
by them gradual contraction during the diastole they keep up the continuous blood- 
current. The elastic element gradually diminishes as we go from the heart toward 
the periphery. The muscular element gradually increases as we go from the aorta 
toward the smaller arteries, where it reaches its maximum. Its function is, by its 
contraction and relaxation, to regulate the amount of blood sent to any part. It 
diminishes, and finally disappears, as we leave the smaller arteries and approach the 
capillaries.] In the largest arteries this coat is of thickness, of a yellow color, 
and highly elastic: it diminishes in thickness and becomes redder in color as the arte- 
ries become smaller, and finally becomes very thin and disappears. In small arteries 
this coat is purely muscular, consisting of muscular fibre-cells (Fig- 45) united to 
form lamellae which vary in number according to the size of the artery, the very 
small arteries having only a single layer, and those not larger than one-tenth of a 
line in diameter three or four layers. In arteries of medium size (Fig. 59) this coat 
becomes thicker in proportion to the size of the vessel; its layers of muscular tissue 
are more numerous and intermixed with numerous fine elastic fibres which unite to 
form broad-meshed networks. In the larger vessels, as the femoral, superior mesen- 
Fig. 58. 
Transverse Section through a Small Artery and 
Vein of the Mucous Membrane of the Epiglottis, 
of a Child (magnified about 350 diameters- 
Klein and Noble Smith): A, artery showing 
the nucleated endothelium, e, which lines it: 
the vessel being contracted, the endothelial 
cells appear very thick. Underneath the endo- 
thelium is the wavy elastic intima. The chief 
part of the wall of the vessel is occupied by the 
circular muscle-coat, m; the staff-shaped nuclei 
of the muscle-cells are well seen. Outside this 
is a, part of the adventitia. This is composed 
of bundles of connective-tissue fibres, shown in 
section, with the nuclei of the connective-tissue 
corpuscles. The adventitia gradually merges 
into the surrounding connective tissue. 
V, vein showing a thin endothelial membrane, e, 
raised accidentally from the intima, which on 
account of its delicacy is seen as a mere line on 
the media, m. This latter is composed of a few 
circular unstriped muscle-cells; a, the adventi- 
tia, similar in structure to that of an artery. 80 
G ENER AL ANA TO M Y. 
teric, coeliac axis, external iliac, brachial, and popliteal arteries, the elastic fibres 
unite to form lamellae, which alternate with the layers of muscular fibre. In the 
largest arteries the muscular tissue is only slightly developed, and forms about one- 
third or one-fourth of the whole substance of the middle coat; this is especially 
the case in the aorta and trunk of the pulmonary artery, in which the individual 
cells of the muscular layer are imperfectly formed, while in the carotid, axillary, 
iliac, and subclavian arteries the muscular layer of the middle coat is more devel- 
oped. The elastic lamellae are well marked, may amount to fifty or sixty in num- 
ber, and alternate regularly 
with the layers of muscular 
tissue. They are most dis- 
tinct and arranged with great 
regularity in the abdominal 
aorta, innominate artery, and 
common carotid. 
The external coat (tunica 
adventitia) consists mainly of 
connective tissue, and contains 
elastic fibres in all but the 
smallest arteries. In the larg- 
est vessels the external coat is 
relatively thin, but in small ar- 
teries it is as thick or thicker 
than the middle coat. In arte- 
ries of the medium size, and 
above it, the external coat is 
formed of two layers, the outer 
of which consists of connective 
tissue containing an irregular 
elastic network, while the in- 
ner is composed of elastic tis- 
sue only. The inner elastic 
coat is very distinct in the 
carotid, femoral, brachial, profunda femoris, mesenteric, and coeliac axis, the elastic 
fibres being often arranged in lamellae. In the smaller arteries the external tunic 
consists of a single layer of mixed connective tissue and elastic fibres; while in the 
smallest arteries, just above the capillaries, the elastic fibres are wanting, and the 
connective tissue, of which the coat is composed, becomes more homogeneous the 
nearer it approaches the capillaries, and is gradually reduced to a thin membranous 
envelope, which finally disappears. 
Some arteries have extremely thin coats in proportion to their size; this is espe- 
cially the case in those situated in the cavity of the cranium and spinal canal, the 
difference depending on the greater thinness of the external and middle coats. The 
arteries in their distribution throughout the body are included in a thin fibro-areolar 
investment, which forms what is called their sheath. In the limbs this is usually 
formed by a prolongation of the deep fascia; in the upper part of the thigh it con- 
sists of a continuation downward of the tranversalis and iliac fascise of the abdomen; 
in the neck, of a prolongation of the deep cervical fascia. The included vessel is 
loosely connected with its sheath by a delicate areolar tissue, and the sheath usually 
encloses the accompanying veins, and sometimes a nerve. Some arteries, as those 
in the cranium, are not included in sheaths. 
All the larger arteries are supplied with blood-vessels like the other organs of 
the body; they are called the vasa vasorum [z. e. vessels of the vessels]. These 
nutrient vessels arise from a branch of the artery or from a neighboring vessel at 
some considerable distance from the point at which they are distributed; they ram- 
ify in the loose areolar tissue connecting the artery with its sheath, and are distrib- 
uted to the external coat, but do not, in man, penetrate the other coats-[hence the 
Fig. 59. 
«, Artery from the Mesentery of a Child, .062"', and b, vein .067"' in 
diameter, treated with acetic acid and magnified 350 times: a, 
tunica adventitia, with elongated nuclei; p, nuclei of the contrac- 
tile fibre-cells of the tunica media, seen partly from the surface, 
partly apparent in transverse section; y, nuclei of the endothelial 
cells; 6, elastic longitudinal fibrous coat. THE VASCULAR SYSTEM. 
81 
danger, in ligating an artery in its continuity, of separating the sheath from it to 
any great extent], though in some of the larger mammals some few vessels have 
been traced into the middle coat. Minute veins serve to return the blood from 
these vessels; they empty themselves into the venae comites in connection with the 
artery. 
Arteries are also supplied with nerves, which are derived chiefly from the sym- 
pathetic, but partly from the cerebro-spinal system. They form intricate plexuses 
upon the surfaces of the larger trunks, the smaller branches being usually accom- 
panied by single filaments. The branches derived from these plexuses penetrate the 
external coat, and are principally distributed to the muscular tissue of the middle 
coat. [These nerves regulate automatically the calibre of the vessels, and hence 
the blood-supply, both in health and disease.] 
[For the lymph-spaces surrounding the blood-vessels (perivascular spaces) see the 
Lymphatic System, p. 87.] 
The Capillaries.-The smaller arterial branches (excepting those of the cavern- 
ous structures of the sexual organs, of the spleen, and in the uterine placenta) ter- 
minate in a network of vessels which pervade nearly every tissue of the body. 
These vessels, from their minute size, are termed capillaries (capillus, a "hair"). 
They are interposed between the smallest branches of the arteries and the commen- 
cing veins, constituting a network the branches of which maintain the same diam- 
eter throughout, the meshes of the network being more uniform in shape and size 
than those formed by the anastomoses of the small arteries and veins. 
The diameter of the capillaries varies in the different tissues of the body, their 
usual size being about -3 oW °f an inch. The smallest are those of the brain and 
the mucous membrane of the intestines; and the largest, those of the skin and the 
marrow of bone, where they are stated to be as large as of an inch. 
The form of the capillary net varies in the different tissues, the meshes being 
generally rounded or elongated. The rounded form of mesh [Fig. 60] is most com- 
[Fig. 60. 
Section of Injected Lung, including several contiguous alveoli (highly magnified): a, a, free edges of alveoli; 
c, c, partitions between neighboring alveoli, seen in section; &, small arterial branch giving off capillaries 
to the alveoli. The looping of the vessels to either side of the partitions is well exhibited. Between the 
capillaries is seen the homogeneous alveolar wall with nuclei of connective-tissue corpuscles and elastic 
fibres (Schafer's Histology').} 
mon, and prevails where there is a dense network, as in the lungs, in most glands 
and mucous membranes, and in the cutis; here the meshes are more or less angular, 
sometimes nearly quadrangular or polygonal, more frequently irregular. 82 
GENERAL ANATOMY. 
Elongated meshes (Fig. 61) are observed in the bundles of fibres and tubes compos- 
ing muscles and nerves, the meshes being usually of a parallelogram form, the long 
axis of the mesh running parallel with the long axis of the nerve and fibre. Some- 
times the capillaries have a looped arrangement, a single vessel projecting from the 
common network and returning after forming one or more loops, as in the papillae 
of the tongue and skin. The number of the capillaries and the size of the meshes 
determine the degree of vascularity of a part. The closest network and the small- 
est interspaces are found in the lungs and in the choroid coat of the eye. In these 
situations the interspaces are smaller than the capillary vessels themselves. In the 
kidney, in the conjunctiva, and in the cutis the interspaces are from three to four 
times as large as the capillaries which form them, and in the brain from eight to ten 
times as large as the capillaries in their long diameter, and from four to six times as 
large in their transverse diameter. In the cellular coat of the arteries the width 
of the meshes is ten times that of the capillary vessels. As a general rule, the 
more active the function of the organ is, the closer is its capillary net and the larger 
its supply of blood, the network being very narrow in all growing parts, in the 
Fig. 61. 
[Fig. 62. 
Section parallel to the surface from the Shaft of the 
Femur (magnified 100 times): a, Haversian canals; 
b, lacunae seen from the side; c, others seen from 
the surface in lamellae which are cut horizontally. 
Small Artery to show the various layers which com- 
pose its walls: a, endothelium; b, internal elastic 
lamina; c, circular muscular fibres of the middle 
coat; d, the connective-tissue outer coat (tunica ad- 
ventitia) (Landois' Physiology, edit, by Stirling).] 
glands, and in the mucous membranes; wider in bones and ligaments, which are 
comparatively inactive; and nearly altogether absent in tendons,'in which very little 
organic change occurs after their formation. 
Structure. 1 he walls of the capillaries consist of a fine, transparent endothe- 
lial layer, composed of cells joined edge to edge by an interstitial cement-substance, 
and continuous with the endothelial cells which line the arteries and veins. [The 
capillaries consist, therefore, purely of the tunica intima, which is reduced wholly 
or almost wholly to the endothelium. This fits them admirably for their function 
of the easy egress (exosmosis) of the fluid pabulum and the oxygen carried by the 
blood to all paits of the body, and the easy ingress (endosmosis) of the carbonic acid 
and other products of destruction by use of the various organs and tissues in solution. 
As we approach the arteries on one side or the veins on the other, the remaining two THE VASCULAR SYSTEM. 
83 
coats are gradually added to the intima (Fig. 62).] When stained with nitrate of sil- 
ver the edges which bound the epithelial cells are brought into view (Figs. 62 and 63). 
These cells are of large size and of an irregular polygonal or lanceolate shape, each 
containing an oval nucleus, which may be brought into view by carmine or logwood. 
Between their edges, at vari- 
ous points of their meeting, 
roundish dark spots are some- 
times seen, which have been 
described as stomata, though 
they are closed by intercell- 
Fig. 64. 
Fig. 63. 
Capillaries from the Mesentery of a 
Guinea-pig, after treatment with so- 
lution of nitrate of silver: a, cells; 
o, their nuclei. 
Finest Vessels on the Arterial Side, from the Human Brain (magni- 
fied 300 times): 1, smallest artery; 2, transition vessel; 3, coarser 
capillaries; 4, finer capillaries; a, structureless membrane still 
with some nuclei, representative of the tunica adventitia; b, nuclei 
of the muscular fibre-cells; c, nuclei within the small artery, per- 
haps appertaining to an endothelium ; d, nuclei in the transition- 
vessels. 
ular substance. They have been believed to be the situation through which the 
white corpuscles of the blood, when migrating through the blood-vessels, emerge; 
but this view, though probable, is not universally accepted. 
In many situations a delicate sheath or envelope of fine connective tissue is 
found around the simple capillary tube, particularly in the larger ones; and in 
other places, especially in the glands, the capillaries are invested with retiform 
lymphatic tissue. 
In the largest capillaries (which ought, perhaps, to be described rather as the 
smallest arteries) traces of an epithelial lining and of circular transverse muscular 
fibres are to be seen (Fig. 64). 
The Veins, like the arteries, are composed of three coats-internal, middle, and 
external; and these coats are, with the necessary modifications, analogous to the 
coats of the arteries, the internal being the epithelial, the middle the muscular, and 
the external the connective or areolar. The main difference between the veins and 
the arteries is in the comparative weakness of the middle coat of the former; and to 
this it is due that the veins do not stand open when divided, as the arteries do, and 
that they are passive rather than active organs of the circulation. 
In the veins immediately above the capillaries the three coats are hardly to be 
distinguished. The endothelium is supported on an outer membrane separable into 
two layers, the outer of which is the thicker, and consists of a delicate, nucleated 
membrane (adventitia), while the inner is composed of a network of longitudinal 
elastic fibres (intima). In the veins next above these in size (one-fifth of a line, 
according to Kolliker) a muscular layer and a layer of circular fibres can be traced. 84 
GENERAL ANATOMY. 
forming the middle coat, while the elastic and connective elements of the outer coat 
become more distinctly perceptible. In the middle-sized veins the typical structure 
of these vessels becomes clear. The endothelium is of the same character as in the 
arteries, but its cells are more oval, less fusiform. It is supported by a connective- 
tissue layer consisting of a delicate network of branched cells, and external to this 
is a layer of longitudinal elastic fibres, but seldom any appearance of a fenestrated 
membrane. This constitutes the internal coat. The middle coat is composed of a 
thick layer of connective tissue with elastic fibres, intermixed, in some veins, with a 
transverse of muscular fibres. The white fibrous element is in considerable 
excess, and the elastic fibres are in much smaller proportion in the veins than in the 
arteries. The outer coat consists of areolar tissue, as in the arteries, with longitu- 
dinal elastic fibres. In the largest veins the outer coat is from two to five times 
thicker than the middle coat, and contains a large number of longitudinal muscular 
fibres. This is most distinct in the hepatic part of the inferior vena cava and at the 
termination of this vein in the heart, in the trunks of the hepatic veins, in all the 
large trunks of the vena portae, in the splenic, superior mesenteric, external iliac, 
renal, and azygos veins. In the renal and portal veins it extends through the whole 
thickness of the outer coat, but in the other veins mentioned a layer of connective 
and elastic tissue is found external to the muscular fibres. All the large veins which 
open into the heart are covered for a short distance with a layer of striped muscular 
tissue continued on to them from the heart. Muscular tissue is wanting in the 
veins-(1) of the maternal part of the placenta; (2) in most of the cerebral veins 
and sinuses of the dura mater; (3) in the veins of the retina; (4) in the veins of 
the cancellous tissue of bones; (5) in the venous spaces of the corpora cavernosa. 
The veins of the above-mentioned parts consist of an internal endothelial lining sup- 
ported on one or more layers of areolar tissue. 
Most veins are provided with valves, which serve to prevent the reflux of the 
blood. They are formed by a reduplication of the inner coat, strengthened by con- 
nective tissue and elastic fibres, and are covered on both surfaces with endothelium. 
Their form is semilunar. They are attached by their convex edge to the wall of 
the vein; the concave margin is free, directed in the course of the venous current, 
and lies in close apposition with the wall of the vein as long as the current of blood 
takes its natural course: if, however, any regurgitation takes place, the valves 
become distended, their opposed edges are brought into contact, and the current is 
intercepted. Most commonly, two such valves are found placed opposite each other, 
more especially in the smaller veins or in the larger trunks at the point where they 
are joined by smaller branches; occasionally there are three, and sometimes only 
one. The wall of the vein immediately above the point of attachment of each seg- 
ment of the valve is expanded into a pouch or sinus, which gives to the vessel, when 
injected or distended with blood, a knotted appearance. [This can readily be seen 
and the position of the valves located by applying a moderately tight bandage around 
one's arm, and then opening and closing the fist several times to increase the blood- 
flow.] The valves are very numerous in the veins of the extremities, especially of 
the lower extremities, these vessels having to conduct the blood against the force of 
gravity. They are absent in the very small veins, also in the venae cavae, the hepat- 
ic veins, portal vein and its branches, the renal, uterine, and ovarian veins. A few 
valves are found in the spermatic veins, and one also at their point of junction with 
the renal vein and inferior vena cava in both sexes. The cerebral and spinal veins, 
the veins of the cancellated tissue of bone, the pulmonary veins, and the umbilical 
vein and its branches are also destitute of valves. They are occasionally found, few 
in number, in the venae azygos and intercostal veins. 
The veins are supplied with nutrient vessels, vasa vasorum, like the arteries. 
Nerves also are distributed to them in the same manner as to the arteries, but in 
much less abundance. 
The Lymphatic vessels-including in this term the Lacteal vessels, which are 
identical in structure with them-are composed of three coats. The internal is an 
endothelial and elastic coat. It is thin, transparent, slightly elastic, and ruptures THE VASCULAR SYSTEM. 
85 
sooner than the other coats. It is composed of a layer of elongated endothelial cells 
with serrated margins, by which the adjacent cells are dovetailed into one another. 
These are supported on a single layer of longitudinal elastic fibres. The middle 
coat is composed of smooth, muscular, and fine elastic fibres, disposed in a transverse 
direction. The external, or fibro-areolar coat, consists of filaments of areolar tissue 
intermixed with smooth muscular fibres, longitudinally or obliquely disposed. It 
forms a protective covering to the other coats, and serves to connect the vessel with 
the neighboring structures. The above description applies only to the larger lym- 
phatics ; in the smaller vessels there is no muscular or elastic coat, and their struc- 
ture consists only of a connective-tissue coat, lined by endothelium. The thoracic 
duct (Fig. 65) is a somewhat more com- 
plex structure than the other lymphatics; 
it presents a distinct subendothelial layer 
of branched corpuscles similar to that 
found in the arteries, and in the middle 
coat is a layer of connective tissue with 
its fibres arranged longitudinally. The 
lymphatics are supplied by nutrient ves- 
sels, which are distributed to their outer 
and middle coats; but no nerves have 
at present been traced into them. 
The lymphatics are very generally 
provided with valves, which assist ma- 
terially in effecting the circulation of 
the fluid they contain. These valves 
are formed of a thin layer of fibrous 
Fig. 66. 
Fig. 65. 
Transverse Section through the Coats of the Thoracic 
Duct of Man (magnified 30 times): a, endothelium, 
striated lamellae, and inner elastic coat; b, longi- 
tudinal connective tissue of the middle coat; c, 
transverse muscles of the same; d, tunica adven- 
titia, with e, the longitudinal muscular fibres. 
1. Endothelium from the under surface of the cen- 
trum tendineum of the rabbit: «, pores or stomata. 
2. Endothelium of the mediastinum of the dog: 
a, pores. 3. Section through the pleura of the same 
animal: b, free orifices of short lateral passages of 
the lymph-canals (copied from Ludwig, Schweig- 
ger-Seydel, and Dybkowsky). 
tissue lined on both surfaces by endothelium. Their form is semilunar; they are 
attached by their convex edge to the sides of the vessel, the concave edge being free 
and directed along the course of the contained current. Usually two such valves, 
of equal size, are found opposite one another; but occasionally exceptions occur, 
especially at or near the anastomoses of lymphatic vessels. Thus, one valve may be 
of very rudimentary size, and the other increased in proportion. 
The valves in the lymphatic vessels are placed at much shorter intervals than in 
the veins. They are most numerous near the lymphatic glands, and they are found 
more frequently in the lymphatics of the neck and upper extremity than in the 
lower. The wall of the lymphatics immediately above the point of attachment of 
each segment of a valve is expanded into a pouch or sinus, which gives to these 
vessels, when distended, the knotted or beaded appearance which they present. 
Valves are wanting in the vessels composing the plexiform network in which the 
lymphatics usually originate on the surface of the body. 
[The lymphatic system is an appendix to the blood-vessels, the latter, especially 
by the capillaries, supplying the oxygen and food to all the tissues, the former carry- 
ing off most of the waste products, and also acting as absorbents. The lymphatic 
vessels arise in several ways. One is in lymph-spaces (Fig. 67) of the connective 86 
GENERAL ANATOMY. 
tissues. Another is in the lacteals, vessels in the intestinal villi (see their descrip- 
tion), which begin by blind or closed extremities. During digestion these vessels 
are filled with the white chyle, but at other times by the colorless lymph. A third 
origin of the lymphatics is in perivascular and perineural spaces. These exist 
especially around the smaller blood-vessels of the nerve-centres, the bones, the 
retina, the liver, and under the sheath of the optic and some other nerves. 
[Fig. 67. 
[Fig. 68. 
Origin of Lymphatics from the Central Tendon of the 
Diaphragm of the Rabbit (semi-diagrammatic): s, the 
juice-canals, communicating at x with the lymphat- 
ics ; a, origin of the lymphatics by the confluence of 
several juice-canals (Landois' Physiology, edit, by Stir- 
ling).] ' 
Perivascular Lymphatics: A, aorta of tor- 
toise. B, artery from the brain; p, peri- 
vascular lymph-space (Landois' Physiology, 
edit, by Stirling).] 
In Fig. 68 the perivascular spaces are shown around the aorta of the tortoise (a), 
which is visible to the naked eye, and (b) around a small cerebral artery. A fourth 
origin is by stomata, or openings between the endothelial cells lining the walls of 
the large serous cavities (Fig. 12, p. 44). These serous cavities, the arachnoid, 
aqueous chambers of the eye, the capsule of Tenon or tunica vaginalis oculi, the 
labyrinth of the ear, the pleura, the pericardium, the peritoneum, and tunica vagi- 
nalis testis, are all, therefore, lymph-sacs. Hence their great absorbing power, 
which it is especially important to recognize in laparotomy and other operations 
involving them.] 
The finest visible lymphatic vessels form a plexiform network in the subcutaneous 
and submucous tissues, and this is properly regarded as one method of their com- 
mencement. But the lymphatics have also other modes of origin, for the intestinal 
lacteals commence by closed extremities, though some observers believe that the 
closed extremity is continuous with a minute network contained in the substance of 
the villus, through which the lacteal is connected with the epithelial cells covering 
it. Again, it seems now to be conclusively proved that the serous membranes pre- 
sent stomata or openings between the endothelial cells (Figs. 12 and 66), by which 
there is an open communication with the lymphatic system, and through which the 
lymph is thought to be pumped by the ultimate dilatation and contraction of the 
serous surface due to the movements of respiration and circulation.1 Von Reck- 
linghausen was the first to observe the passage of milk and other colored fluids 
through these stomata on the peritoneal surface of the central tendon of the dia- 
phragm. Again, in most glandular structures the lymphatic capillaries have a 
1 The resemblance between lymph and serum led Hewson long ago to regard the serous cavities as 
sacs into which the lymphatics open. Recent microscopic discoveries confirm this opinion in a very 
interesting manner. THE VASCULAR SYSTEM. 
87 
lacunar origin. Here they begin in irregular clefts or spaces in the tissue of the 
part; and closely corresponding to or identical with this is their origin in connec- 
tive tissue, where the lymphatic vessels are apparently continuous with spaces in 
the connective tissue; and Klein has described and figured a direct communication 
between these spaces and the lymphatic vessel.1 
Lymphatic Glands (Fig. 69) are small oval or bean-shaped bodies situated in 
the course of lymphatic and lacteal vessels, so that the lymph and chyle pass through 
them on their way to the blood. They 
generally present on one side a slight 
depression-the hilum-through which 
the blood-vessels enter and leave the 
interior. The efferent lymphatic vessel 
also emerges from the gland at this spot, 
while the afferent vessels enter the organ 
at different parts of the periphery. On 
section, a lymphatic gland displays two 
different structures: an external, of 
lighter color-the cortical; and an in- 
ternal, darker-the medullary. The cor- 
tical structure does not form a complete 
investment, but is deficient at the hilum, 
where the medullary portion reaches the 
surface of the gland; so that the efferent 
vessel is derived directly from the medul- 
lary structure, while the afferent vessels 
empty themselves into the cortical sub- 
stance. 
Lymphatic glands consist of (1) a fib- 
rous envelope, or capsule, from which a framework of processes (trabecula?) proceed 
inward, dividing the gland into open spaces (alveoli) freely communicating with 
each other; (2) a quantity of adenoid tissue occupying these spaces without com- 
pletely filling them; (3) a free supply of blood-vessels, which are supported on the 
trabeculae ; and (4) the afferent and efferent vessels. Little is known of the nerves, 
though Kolliker describes some fine nervous filaments passing into the hilum. 
The capsule is composed of a layer of connective tissue, and from its internal 
surface are given off a number of membranous septa or lamellae which pass inward, 
radiating toward the centre of the gland, for a certain distance; that is to say, for 
about one-third or one-fourth of the space between the circumference and the centre 
of the gland. They thus divide the outer part of its interior into a number of oval 
compartments or alveoli (Fig. 69). This is the cortical portion of the gland. After 
having penetrated into the gland for some distance, these septa break up into a num- 
ber of smaller trabeculae, which form flattened bands or cords interlacing with each 
other in all directions, forming in the central part of the organ a number of inter- 
communicating spaces, also called alveoli. This is the medullary portion of the 
gland, and the spaces or alveoli in it not only freely communicate with each other, 
but also with the alveoli of the cortical portion. In these alveoli or spaces (Fig. 70) 
is contained the proper gland-substance or lymphoid tissue. The gland-pulp does 
not, however, completely fill the alveolar spaces, but leaves, between its outer mar- 
gin and the trabeculae forming the alveoli, a channel or space of uniform width 
throughout. This is termed the lymph-path or lymph-sinus (Figs. 71 and 72). 
Running across it are a number of trabeculae of retiform connective tissue, which 
appear to serve the purpose of maintaining the gland-pulp in the centre of the 
space in its proper position. 
On account of the peculiar arrangement of the framework of the organ the 
gland-pulp in the cortical portion is disposed in the form of nodules, and in the 
medullary part in the form of rounded cords. It consists of ordinary lymphoid 
Fig. 69. 
Section of Small Lymphatic Gland, half-diagram- 
matically given, with the course of the lymph: 
a, the envelope: b, septa between the follicles or 
alveoli of the cortical part; c, system of septa of the 
medullary portion, down to the hilum; a, the fol- 
licles ; e, lymph-tubes of the medullary mass; f, dif- 
ferent lymphatic streams which surround the folli- 
cles and flow through the interstices of the medul- 
lary portion; g, confluence of these passing through 
the efferent vessel, h, at the hilum. 
1 Atlas of Histology, pl. viii. fig. xiv. 88 
GENERAL ANATOMY. 
tissue, being made up of a delicate reticulum of retiform tissue, which is continuous 
with that in the lymph-paths, but marked off from it by a closer reticulation; in its 
Fig. 70. 
Fig. 71. 
Follicle from a Lymphatic Gland of the Dog, in vertical 
section : a, reticular sustentacular substance of the more 
external portion; b, of the more internal, and c, of the 
most external and most finely webbed part on the sur- 
face of the follicle; d, origin of a large lymph-tube; e, 
of a smaller one; /, capsule; g, septa; h, vas afferens; i, 
investing space of the follicle, with its retinacula; k, one 
of the divisions of the septa; I, I, attachment of the 
lymph-tubes to the septa. 
From the Medullary Substance of 
an Inguinal Gland of the Ox 
(after His): a, lymph-tube, with 
its complicated system of vessels; 
b, retinacula stretched between 
the tube and the septa; c, portion 
of another lymph-tube; d, septa. 
meshes are closely-packed lymph-corpuscles, traversed by a dense plexus of capillary 
blood-vessels. 
The afferent vessels, as above stated, enter at all parts of the periphery of the 
gland, and, after branching and forming a dense plexus in the substance of the cap- 
sule, open into the lymph- 
sinuses of the cortical part. 
In doing this they lose all 
their coats except their endo- 
thelial lining, which is con- 
tinuous with a layer of similar 
cells lining the lymph-paths. 
In like manner the efferent 
vessel commences from the 
lymph-sinuses of the medullary 
portion. The stream of lymph 
carried to the gland by the 
afferent vessel would thus pass 
through the plexus in the cap- 
sule to the lymph-paths of the 
cortical portion, where it would 
be exposed to the action of the 
gland-pulp; flowing through 
these, it would enter the paths 
or sinuses of the medullary 
portion, and finally emerge from the hilum by means of the efferent vessel. [This 
passage of the lymph-stream through the glands explains readily the glandular 
enlargement that follows chancre, vaccination, malignant tumors, etc.] The arteries 
of the gland enter at the hilum, and either pass at once to the gland-pulp to break 
Fig. 72. 
Section of Lymphatic Gland-tissue: a, trabeculae; b, small artery in 
substance of .same; c, lymph-paths; d, lymph-corpuscles; e, capil- 
lary plexus. THE SKIN AND ITS APPENDAGES. 
89 
up into a capillary plexus, or else run along the trabeculae, partly to supply them, 
and partly running across the lymph-paths to assist in forming the capillary plexus 
of the gland-pulp. From this plexus the veins commence, and emerge from the 
organ at the same place as that at which the artery enters. 
The Skin (Fig. 73) is the principal seat of the sense of touch, and may be 
regarded as a covering for the protection of the deeper tissues; it is also an import- 
ant excretory and absorbing organ. It consists principally of a layer of vascular 
tissue, named the derma or 
cutis vera, and an external 
covering of epithelium, term- 
ed the epidermis or cuticle. 
On the surface of the former 
layer are the sensitive papil- 
Ice; and within or imbedded 
beneath it are certain organs 
with special functions-name- 
ly, the sweat-glands, hair-fol- 
licles, and sebaceous glands. 
The Epidermis or Cuti- 
cle (scarf-skin, Fig. 74) is an 
epithelial structure belonging 
to the class of stratified epi- 
thelia. It is accurately mould- 
ed on the papillary layer of 
the derma. It forms a de- 
fensive covering to the surface 
of the true skin and limits the 
evaporation of watery vapor 
from its free surface. It varies 
in thickness in different parts. 
In some situations, as in the 
palms of the hands and soles 
of the feet, it is thick, hard, 
and horny in texture. This 
may be partly due to the fact 
that these parts are exposed 
to intermittent pressure; but 
that this is not the sole cause 
is proved by the fact that the 
condition exists to a very considerable extent at birth. The more superficial layer 
of cells, called the horny layer (stratum corneum), may be separated by maceration 
from the deeper layers, which are called the rate mucosum, and which consist of 
several layers of differently-shaped cells. The free surface of the epidermis is 
marked by a network of linear furrows of variable size, marking out the surface 
into a number of spaces of polygonal or lozenge-shaped form. Some of these fur- 
rows are large, as opposite the flexures of the joints, and correspond to the folds in 
the derma produced by their movements. In other situations, as upon the back of 
the hand, they are exceedingly fine, and intersect one another at various angles; 
upon the palmar surface of the hand and fingers and upon the sole of the foot these 
lines are very distinct and are disposed in curves. They depend upon the large size 
and peculiar arrangement of the papillae upon which the epidermis is placed. The 
deep surface of the epidermis is accurately moulded upon the papillary layer of the 
derma, each papilla being invested by its epidermic sheath ; so that when this layer 
THE SKIN AND ITS APPENDAGES. 
Fig. 73. 
Jfwi-rs 
Swfiwrfieii*- I 
luy frt 
JRete 
jyfi.ee oru.?n> 
iPaJ/iillw- 
Coriu/tn/ • 
jBfiitlc'nmfc 
, or 
Cuticle 
JDernv 
' or 
C utc 
i'ut Ce7hf 
tiisuf. " 
-cutocncous 
CctiuZtir 
Sebaceous 
Glands 
'Sweat Cl aid's 
Nutrient Artery 
A Sectional View of the Skin (magnified). 90 
GENERAL ANATOMY. 
is removed by maceration it presents on its under surface a number of pits or depres- 
sions corresponding to the elevations in the papillae, as well as the ridges left in the 
intervals between them. Fine tubular prolongations are continued from this layer 
into the ducts of the sudoriferous and sebaceous glands. 
In structure the epidermis consists of several layers of epithelial cells aggluti- 
nated together and having a laminated arrangement. These several layers may be 
described as composed of four different strata: (1) The rete Malpighii, composed of 
several layers of epithelial cells, which are elongated in figure and placed perpen- 
dicularly on the surface of the corium. Of these the deepest layer is composed of 
columnar cells arranged perpendicularly, while the succeeding laminse consist of 
Fig. 74. 
Mieroscopic Section of Skin, showing the epidermis (a) and derma (&); a hair (c) in its follicle; the erector pili 
muscle (d); sebaceous (e) and sudoriferous (/) glands. 
cells of a more rounded or polyhedral form, the contents of which are soft, opaque, 
granular, and soluble in acetic acid. They are often marked on their surfaces with 
ridges and furrows, and are covered with numerous spines. (2) Immediately super- 
ficial to these is a single layer of flattened, spindle-shaped cells, the granular layer, 
which contain granules that become deeply stained in haematoxylin. They are sup- 
posed to be cells in a transitional stage between the protoplasmic cells of the rete 
Malpighii and the horny cells of the superficial layers. (3) Above this layer the 
cells become indistinct, and appear, in sections, to form a homogeneous or dimly- 
striated membrane composed of closely-packed scales, and hence called the stratum 
lucidum. (I) As these cells successively approach the surface by the development 
of fresh layers from beneath, they assume a flattened form from the evaporation of 
their fluid contents, and consist of many layers of horny epithelial scales, forming 
the stratum corneum. These cells apparently become changed in their chemical 
composition, as they are now unaffected by acetic acid. The deepest layer of the 
rete Malpighii is separated from the papillae by an apparently homogeneous base- 
ment-membrane, which is most distinctly brought into view in specimens prepared 
with chloride of gold. This, according to Klein, is merely the deepest portion of 
the epithelium, and is "made up of the basis of the individual cells, which have 
undergone a chemical and morphological alteration." The black color of the skin 
in the negro, and the tawny color among some of the white races, are due to the 
presence of pigment in the cells of the cuticle. This pigment is more especially 
distinct in the cells of the deeper layer, or rete mucosum, and is similar to that 
found in the cells of the pigmentary layer of the retina. As the cells approach the 
surface and desiccate the color becomes partially lost. 
The Derma, Corium, or Cutis vera is tough, flexible, and highly elastic, in 
order to defend the parts beneath from violence. It consists of fibrous connective 
tissue, with a large admixture of elastic fibres and numerous blood-vessels, lymph- THE SKIN AND ITS APPENDAGES. 
91 
atics, and nerves. The corium varies in thickness from a quarter of a line to a line 
and a half in different parts of the body. Thus, it is very thick in the palms of the 
hands and soles of the feet; thicker on the posterior aspect of the body than the 
front, and on the outer than the inner side of the limbs. In the eyelids, scrotum, 
and penis it is exceedingly thin and delicate. The skin generally is thicker in the 
male than in the female, and in the adult than in the child. Unstriped muscular 
fibres are found in the superficial layers of the corium wherever hairs are found, and 
in the subcutaneous areolar tissue of the scrotum, penis, perineum, and areolae of the 
nipples. In the latter situation the fibres are arranged in bands closely reticulated 
and disposed in superimposed laminae. The fibro-areolar tissue forms the frame- 
work of the cutis, and is differently arranged in different parts, so that it is usual to 
describe it as consisting of two layers: the deeper or reticular layer, and the super- 
ficial or papillary layer. 
The reticular layer consists of strong interlacing fibrous bands, composed chiefly 
of the white variety of fibrous tissue, but containing also some fibres of the yellow 
elastic tissue, which vary in amount in different parts, and connective-tissue corpus- 
cles, which are often to be found flattened against the white fibrous-tissue bundles. 
Toward the attached surface the fasciculi are 
large and coarse, and the areolae which are left 
by their interlacement are large and occupied 
by adipose tissue and sweat-glands. Below this 
the elements of the skin become gradually blend- 
ed with the subcutaneous areolar tissue, which, 
except in a few situations, contains fat. Toward 
the free surface the fasciculi are much finer, and 
their mode of interlacing close and intricate. 
The papillary layer is situated upon the free 
surface of the reticular layer; it consists of nu- 
merous small, highly sensitive, and vascular em- 
inences, the papillce (Fig. 75), which rise per- 
pendicularly from its surface and form the essen- 
tial element of the organ of touch. The papillae 
are conical-shaped eminences, having a round 
or blunted extremity, occasionally divided into 
two or more parts, and connected by a thin base 
with the free surface of the corium. Their aver- 
age length is about of an inch, and they 
measure at their base of an inch in diame- 
ter. On the surface of the body, more especial- 
ly in those parts which are endowed with slight 
sensibility, they are few in number, short, exceedingly minute, and irregularly 
scattered over the surface; but in other situations, as upon the palmar surface of 
the hands and fingers, upon the plantar surface of the feet and toes, and around 
the nipple, they are long, of large size, closely aggregated together, and arranged 
in parallel curved lines, forming the elevated ridges seen on the free surface 
of the epidermis. In these ridges the larger papillae are arranged in a double 
row, with smaller papillae between them ; and these rows are subdivided into small 
square-shaped spaces by short transverse furrows, regularly disposed ; in the centre 
of each of these spaces is the minute orifice of the duct of a sweat-gland. No 
papillae exist in the grooves between the ridges. In structure the papillae resemble 
the superficial layer of the cutis, consisting of very small and closely interlacing 
bundles of finely fibrillated tissue, with a few elastic fibres. 
The arteries supplying the skin form a network in the subcutaneous tissue, from 
which branches are given off to supply the sweat-glands, the hair-follicles, and the 
fat. Other branches are given off which form a plexus immediately beneath the 
corium ; from this fine capillary vessels pass into the papillae, forming, in the smaller 
papillae, a single capillary loop, but in the larger a more or less convoluted vessel. 
[Fig. 75. 
DU CT. SWEAT GL 
Epidermis detached from Derma by Mace- 
ration, and then turned upward (X 20). It 
shows on the under surface of the epi- 
dermis, in double lines, the hollows which 
receive the papillee. The papillse show on 
the surface of the derma. The concentric 
lines on the last phalanges of the fingers 
are caused by them. The ducts of the 
sweat-glands, some of which are broken, are 
well shown (Hirschfeldt).] 92 
GENERAL ANATOMY. 
The nerves of the skin terminate partly in the epidermis and partly in the cutis 
vera. The former form a dense plexus in the superficial layer of the corium, which 
extends horizontally and gives off numerous branches; these are prolonged into the 
epidermis and terminate between the cells, either in bulbous extremities or in a net- 
work. The latter terminate in end-bulbs, touch-corpuscles, or Pacinian bodies in 
the manner already described [p. 42]. There are numerous lymphatics supplied to 
the skin, which form two networks superficial and deep, communicating with each 
other and with those of the subcutaneous tissue by oblique branches. 
The Appendages of the Skin are the nails, the hairs, the sudoriferous and 
sebaceous glands, and their ducts. 
The nails and hairs are peculiar modifications of the epidermis, consisting essen- 
tially of the same cellular structure as that membrane. 
The Nails are flattened, elastic structures of a horny texture placed upon the 
dorsal surface of the terminal phalanges of the fingers and toes. Each nail is. 
convex on its outer surface, concave within, and is implanted by a portion, called 
the root, into a groove in the skin; the exposed portion is called the body, and the 
anterior extremity the free edge. The nail has a very firm adhesion to the cutis, 
being accurately moulded upon its surface, as the epidermis is in other parts. The 
part of the cutis beneath the body and root of the nail is called the matrix, because 
it is the part from which the nail is produced. Corresponding to the body of the 
nail, the matrix is thick, and covered with large, highly vascular papillae arranged 
in longitudinal rows, the color of which is seen through the transparent tissue. 
Behind this, near the root of the nail, the papillae are small, less vascular, and have 
no regular arrangement; and here the tissue of the nail is somewhat more opaque; 
hence this portion is of a whiter color, and is called the lunula on account of its 
shape. 
The cuticle, as it passes forward on the dorsal surface of the finger or toe, is 
attached to the surface of the nail a little in advance of its root; at the extremity 
of the finger it is connected with the under surface of the nail a little behind its 
free edge. The cuticle and horny substance of the nail (both epidermic structures) 
are thus directly continuous with each other. The nails, in structure, consist of 
cells having a laminated arrangement, and these are essentially similar to those 
composing the epidermis. The deepest layer of cells, which lie in contact with the 
papillae of the matrix, are of elongated form, arranged perpendicularly to the sur- 
face, and provided with nuclei; those which succeed them are of a rounded or polyg- 
onal form, the more superficial ones becoming broad, thin, and flattened, and so 
closely compacted as to make the limits of each cell very indistinct. It is by the 
successive growth of new cells at the root and under surface of the body of the nail 
that it advances forward and maintains a due thickness, whilst at the same time the 
growth of the nail in the proper direction is secured. As these cells in their turn 
become displaced by the growth of new cells, they assume a flattened form, lose 
their nuclei, and finally become closely compacted together into a firm, dense, 
horny texture. In chemical composition the nails resemble epidermis. According 
to Mulder, they contain a somewhat larger proportion of carbon and sulphur. 
The Hairs are peculiar modifications of the epidermis, and consist essentially of 
the same structure as that membrane. They are found on nearly every part of the 
surface of the body, excepting the palms of the hands, soles of the feet, and the penis. 
They vary much in length, thickness, and color in different parts of the body and 
in different races of mankind. In some parts, as in the skin of the eyelids, they 
are so short as not to project beyond the follicles containing them; in other parts, 
as upon the scalp, they are of considerable length; again, in other parts, as the eye- 
lashes, the hairs of the pubic region, and the male whiskers and beard, they are 
remarkable for their thickness. The hairs generally present a cylindrical or more or 
less flattened form, and a reniform outline upon transverse section. 
A hair consists of a root, the part implanted in the skin; the shaft or stem, the 
portion projecting from its surface; and the point. 
The root of the hair presents at its extremity a bulbous enlargement, which is THE SKIN AND ITS APPENDAGES. 
93 
whiter in color and softer in texture than the shaft, and is lodged in a follicular invo- 
lution of the epidermis called the hair-follicle. When the hair is of considerable 
length the follicle extends into the subcutaneous cellular tissue. The hair-follicle 
commences on the surface of the skin with a funnel-shaped opening, and passes 
inward in an oblique direction, to become dilated at its deep extremity to correspond 
with the bulbous condition of the hair which it contains. It has opening into it, 
near its free extremity, the orifices of the ducts of one or more sebaceous glands 
(Fig. 74). At the bottom of each hair-follicle is a small conical vascular eminence 
or papilla similar in every respect to those found upon the surface of the skin; it is 
continuous with the dermic layer of the follicle, is highly vascular, and probably 
supplied with nervous fibrils: this is the part through 
which material is supplied for the production and con 
stant growth of the hair. In structure the hair-follicle 
consists of two coats-an outer or dermic, and an inner 
or cuticular. 
The outer or dermic coat is formed mainly of fibrous 
tissue; it is continuous with the corium, is highly vas- 
cular, and supplied by numerous minute nervous fila- 
ments. It consists of three layers (Fig. 76). The 
most internal, next the cuticular lining of the follicle, 
consists of a hyaline basement-membrane having a 
glassy, transparent appearance, which is well marked 
in the larger hair-follicles, but is not very distinct in 
the follicles of minute hairs. It is continuous with 
the basement-membrane of the surface of the corium. 
External to this is a layer of spindle-shaped cells 
.arranged in a circular manner around the follicle, but 
reaching only as high as the entrance of the ducts of 
the sebaceous glands. This is usually regarded as a 
muscular layer, the cells resembling unstriped-muscle 
cells. Externally is a thick layer of connective tissue, 
arranged in longitudinal bundles, in which are con- 
tained the blood-vessels and nerves. 
The inner or cuticular layer is continuous with the 
epidermis, and at the bottom of the hair-follicle with 
the root of the hair; this cuticular lining resembles the epidermis in the peculiar 
rounded form and soft character of those cells which lie in contact with the outer 
coat of the hair-follicle, and the thin, dry, and scaly character of those which lie 
near the surface of the hair, to which they are closely adherent. When the hair is 
plucked from its follicle the cuticular lining most commonly adheres to it and forms 
what is called the root-sheath. 
The hair-follicle contains the root of the hair, which terminates in a bulbous 
■extremity, and is excavated so as to exactly fit the papilla from which it grows. 
The bulb is composed of polyhedral epithelial cells, which, as they pass upward into 
the root of the hair, become elongated and spindle-shaped, except some in the centre, 
which remain polyhedral. Some of these latter cells contain pigment-granules, 
which give rise to the color of the hair. It occasionally happens that these pig- 
ment-granules completely fill the cells in the centre of the bulb, which gives rise to 
the dark tract of pigment often found, of greater or less length, in the axis of the 
hair. 
The shaft of the hair consists of a central pith or medulla, the fibrous part of the 
hair, and the cortex externally. The medulla occupies the centre of the shaft and 
ceases toward the point of the hair. It is usually wanting in the fine hairs covering 
the surface of the body, and commonly in those of the head. It is more opaque 
and deeper-colored than the fibrous part, and consists of cells containing pigment- 
or fat-granules. The fibrous portion of the hair constitutes the chief part of the 
■shaft; its cells are elongated and unite to form flattened fusiform fibres. Between 
Fig. 76. 
Transverse Section of Hair-follicle: 
1. Dermic coat of follicle. 2. Epi- 
dermic coat or root-sheath: a, 
outer layer of dermic coat, with 
blood-vessels; b, b, cut across; 
c, middle layer; d, inner or hya- 
line layer; e, outer root-sheath , 
/, g, inner-root-sheatb : h, cuticle 
of root-sheath; i, hair (from 
Quoin's Anatomy, Biesiadecki). 94 
G ENERAL ANATOMY. 
the fibres are found minute spaces which contain either pigment-granules in dark 
hair or minute air-bubbles in white hair. In addition to this there is also a diffused 
pigment contained in the fibres. The cells which form the cortex of the hair con- 
sist of a single layer which surrounds those of the fibrous part; they are converted 
into thin, flat scales having an imbricated arrangement. 
Connected with the hair-follicles are minute bundles of involuntary muscular 
fibres termed the erectores pili. They arise from the superficial layer of the corium, 
and are inserted into the outer surface of the hair-follicle below the entrance of the 
duct of the sebaceous gland. They are placed on the side toward which the hair 
slopes, and by their action elevate the hair (Fig. 74). 
The Sebaceous Glands are small, sacculated, glandular organs lodged in the 
substance of the corium. They are found in most parts of the skin, but are most 
abundant in the scalp and face; they are also very numerous around the apertures 
of the anus, nose, mouth, and external ear; but are wanting in the palms of the 
hands and soles of the feet. Each gland consists of a single duct, more or less 
capacious, which terminates in a cluster of small secreting pouches or saccules. The 
sacculi connected with each duct vary, as a rule, in numbers from, two to five, but in 
some instances may be as many as twenty. They are composed of a transparent, 
colorless membrane enclosing a number of cells. Of these, the outer layer or mar- 
ginal cells are small, polyhedral, epithelial cells, continuous with the lining cells of 
the duct. The remainder of the sac is filled with larger cells containing fat, except 
in the centre, where the cells have become broken up, leaving a cavity containing 
the ddbris of cells and a mass of fatty matter which constitutes the sebaceous secre- 
tion. The orifices of the ducts open most frequently into the hair-follicles, but occa- 
sionally upon the general surface. On the nose and face the glands are of large size, 
distinctly lobulated, and often become much enlarged from the accumulation of pent- 
up secretion. The largest sebaceous glands are those found in the eyelids-the 
Meibomian glands. 
The Sudoriferous or Sweat Glands are the organs by which a large portion of 
the aqueous and gaseous materials is excreted by the skin. They are found in 
almost every part of this structure, and are situated in small pits in the deep parts 
of the corium, or more frequently in the subcutaneous areolar tissue, surrounded by 
a quantity of adipose tissue. They are small, lobular, reddish bodies, consisting of 
a single convoluted tube, from which the efferent duct proceeds upward through the 
corium and cuticle, becomes somewhat dilated at its extremity, and opens on the 
surface of the cuticle by an oblique valve-like aperture. The efferent duct, as it 
passes through the epidermis, presents a spiral arrangement, being twisted like a 
corkscrew in those parts where the epidermis is thick; where, however, it is thin the 
spiral arrangement does not exist. In the superficial layers of the corium the duct 
is straight, but in the deeper layers it is convoluted or even twisted. The spiral 
course of these ducts is especially distinct in the thick cuticle of the palm of the 
hand and sole of the foot. The size of the glands varies. They are especially large 
in those regions where the amount of perspiration is great, as in the axillae, where 
they form a thin mammillated layer of a reddish color, which corresponds exactly to 
the situation of the hair in this region; they are large also in the groin. Their 
number varies. They are most numerous on the palm of the hand, presenting, 
according to Krause, 2800 orifices on a square inch of the integument, and are rather 
less numerous on the sole of the foot. In both of these situations the orifices of the 
ducts are exceedingly regular, and correspond to the small transverse grooves which 
intersect the ridges of papillae. In other situations they are more irregularly scat- 
tered, but in nearly equal numbers, over parts including the same extent of surface. 
In the neck and back they are least numerous, their number amounting to 417 on 
the square inch (Krause). Their total number is estimated by the same writer at 
2,381,248, and, supposing the aperture of each gland to represent a surface of of 
a line in diameter, he calculates that the whole of these glands would present an 
evaporating surface of about eight square inches. Each gland consists of a single 
tube intricately convoluted, terminating at one end by a blind extremity, and open- SEROUS MEMBRANES. 
95 
ing at the other end upon the surface of the skin. In the larger glands this single 
duct usually divides and subdivides dichotomously, the smaller ducts ultimately ter- 
minating in short caecal pouches, rarely anastomosing. The wall of the duct is thick, 
the width of the canal rarely exceeding one-third of its diameter. The tube, both in 
the gland and where it forms the excretory duct, consists of two layers-an outer, 
formed by fine areolar tissue, and an inner layer of epithelium. The external or 
fibro-cellular coat is thin, continuous with the superficial layer of the corium, and 
extends only as high as the surface of the true skin. The epithelial lining in the 
gland proper consists of a single layer of cubical epithelium, and beneath it, between 
the epithelium and the fibro-cellular coat, a layer of plain muscular fibres arranged 
longitudinally. In the duct there are two or more layers of epithelial cells, but no 
muscular fibres. The epithelium is continuous with the epidermis, and alone forms 
the spiral portion of the tube. When the cuticle is carefully removed from the sur- 
face of the cutis these convoluted tubes of epithelium may be drawn out, and form 
short, thread-like processes on its under surface. [See Fig. 75.] 
The contents of the smaller sweat-glands are quite fluid, but in the larger glands 
the contents are semifluid and opaque, and contain a number of colored granules 
and cells which appear analogous to epithelial cells. 
SEROUS MEMBRANES. 
The Serous Membranes form shut sacs, of which one portion is applied to the 
walls of the cavity which it lines-the parietal portion ; the other is reflected over 
the surface of the organ or organs contained in the cavity-the visceral portion. 
Sometimes the sac is arranged quite simply, as the tunica vaginalis testis; at others 
with numerous involutions or recesses, as the peritoneum, in which, nevertheless, the 
membrane can always be traced continuously around the whole circumference. The 
sac is completely closed, so that no communication exists between the serous cavity 
and the parts in its neighborhood. An apparent exception exists in the peritoneum 
of the female; for the Fallopian tube opens freely into the peritoneal cavity in the 
dead subject, so that a bristle can be passed from the one into the other. But this 
communication is closed during life, except at the moment of the passage of the 
ovum out of the ovary into the tube, as is proved by the fact that no interchange of 
fluids ever takes place between the two cavities in dropsy of the peritoneum or in 
accumulation of fluid in the Fallopian tubes.1 A serous membrane is often sup- 
ported by a firm, fibrous layer, as is the case with the pericardium, and such mem- 
branes are sometimes spoken of as " fibro-serous." 
The various serous membranes are the peritoneum, lining the cavity of the abdo- 
men ; the two pleurae and the pericardium, lining the lungs and heart respectively; 
and the tunica vaginalis, surrounding each testicle in the scrotum.2 Serous mem- 
branes are thin, transparent, glistening structures, lined on their inner surface by a 
single layer of polygonal or pavement-endothelial cells, supported on a matrix of 
fibrous connective tissue, with networks of fine elastic fibres, in which are contained 
numerous capillaries and lymphatics. On the surface of the endothelium between 
the cells numerous apertures or interruptions are to be seen. Some of these are 
stomata, surrounded by a ring of cubical endothelium (see Fig. 12) and communicate 
with a lymphatic capillary (see p. 51); others (pseudo-stomata) are mere interrup- 
tions in the epithelial layer, and are occupied by processes of the branched connec- 
tive-tissue corpuscles of the subjacent tissue or by accumulations of the intercellular 
cement-substance. [The serous membranes, together with the arachnoid, are lymph- 
1 The communication between the uterine cavity and the peritoneal sac is not only apparent in 
the dead subject, but is an anatomical fact which is established by the continuity of its epithelium 
with that covering the uterus, Fallopian tubes, and fimbriae. 
2 The arachnoid membrane lining the brain and spinal cord was formerly regarded as a serous 
membrane, but is now no longer classed with them, as it differs from them in structure, and does not 
form a shut sac, as do the other serous membranes. 96 
GENERAL ANATOMY. 
sacs, from which lymphatics arise by the stomata. Hence the great danger of septic 
inflammation in them in consequence of the large surface and rapid absorption.] 
The secretion of these membranes is, in most cases, only sufficient in quantity to 
moisten the surface, but not to furnish any appreciable quantity of fluid. When a 
small quantity can be collected, it appears to resemble in many respects the lymph, 
and like that fluid coagulates spontaneously; but when secreted in large quantities, 
as in dropsy, it is a watery fluid, which gives a precipitate of albumen on boiling. 
SYNOVIAL MEMBRANES. 
Synovial Membranes, like serous membranes, are connective-tissue membranes 
placed between two movable tissues, so as to diminish friction, as between the two 
articular ends of the bones forming a movable joint; between a tendon and a bone, 
where the former glides over the latter; and between the skin and various sub- 
cutaneous bony prominences. 
The synovial membranes are composed essentially of connective tissue, with the 
cells and fibres of that structure, containing numerous vessels and nerves. It was 
formerly supposed that these membranes were analogous in structure to the serous 
membranes, and consisted of a layer of flattened cells on a basement-membrane. No 
such cells, however, exist, and the only ones found on the surface are irregularly- 
branched connective-tissue corpuscles, similar to those found throughout the tissue. 
Here and there these cells are collected in patches and present the appearance of 
endothelium, but do not possess the true characters of an endothelial layer. They 
are surrounded and held together by an albuminous ground-substance. A further 
description of the synovial membranes will be found in the Descriptive Anatomy of 
the Joints. 
MUCOUS MEMBRANES. 
Mucous Membranes line all those passages by which the internal parts com- 
municate with the exterior, and are continuous with the skin at the various orifices 
of the surface of the body. They are soft and velvety and very vascular, and their 
surface is coated over by their secretion, mucus, which is of a tenacious consistence, 
and serves to protect them from the foreign substances introduced into the body with 
which they are brought in contact. 
They are described as lining the two tracts-the gastro-pulmonary and the genito- 
urinary ; and all or almost all mucous membranes may be classed as belonging to and 
continuous with the one or the other of these tracts. 
The external surfaces of these membranes are attached to the parts which they 
line by means of connective tissue, which is sometimes very abundant, forming a 
loose and lax bed, so as to allow considerable movement of the opposed surfaces on 
each other. It is then termed the submucous tissue. At other times it is exceed- 
ingly scanty, and the membrane is closely connected to the tissue beneath-some- 
times, for example, to muscle, as in the tongue; sometimes to cartilage, as in the 
larynx; and sometimes to bone, as in the nasal fossae and sinuses of the skull. 
In structure a mucous membrane is composed of corium and epithelium. The 
epithelium is of various forms, including the squamous, columnar, and ciliated, and 
is often arranged in several layers. (See Fig. 11.) This epithelial layer is sup- 
ported by the corium, which is analogous to the derma of the skin, and consists of 
connective tissue, either simply areolar or containing a greater or less quantity of 
lymphoid tissue. This tissue is usually covered on its external surface by a trans- 
parent structureless basement-membrane, and internally merges into the submucous 
areolar tissue. It is only in some situations that the basement-membrane can be 
demonstrated. The corium is an exceedingly vascular membrane, containing a dense 
network of capillaries, which lie immediately beneath the epithelium and are derived 
from small arteries in the submucous tissue. SECRETING GLANDS. 
97 
The fibro-vascular layer of the corium contains, besides the areolar tissue and 
vessels, unstriped muscle-cells, which form in many situations a definite layer, called 
the muscularis mucosce. [See the description of the Small Intestine.] This is 
situated in the deepest part of the membrane, and is plentifully supplied with 
nerves. In addition to these nerves, others pass to the epithelium and terminate 
between the cells. Lymphatic vessels are found in great abundance, commencing 
either by csecal extremities or in networks, and communicating with plexuses in the 
submucous tissue. 
Imbedded in the mucous membrane are found numerous glands, and, projecting 
from it, are processes (villi and papillae) analogous to the papillae of the skin. These 
glands and processes, however, exist only at certain parts; and it will be more con- 
venient to refer for their description to the sequel, where the parts are described as 
they occur. 
SECRETING GLANDS. 
The Secreting- Glands are organs in which the blood, circulating in capillary 
vessels, is brought into contact with epithelial cells, whereby certain elements are 
separated ("secreted") out of the blood. The essential parts, therefore, of a secret- 
ing gland are cells, which have the power of extracting from the blood certain mat- 
ters, and in some cases converting them into new chemical compounds; and blood- 
vessels, by which the blood is brought into close relationship with these cells. The 
general arrangement in all secreting structures-that is to say, not only in secreting 
glands, but also in secreting membranes-is for the cells to be arranged on one sur- 
face of an extra-vascular basement-membrane, which supports them, and for a minute 
plexus of capillary vessels to ramify on the other surface of the membrane. The cells 
then extract from the blood certain constituents which pass through the membrane 
into the cells, where they are prepared and elaborated. The basement-membrane 
does not, however, always exist, and any free surface would appear to answer the 
same purpose in some cases. 
By the various modifications of this secreting surface the different glands are 
formed. This is generally effected by an involution of the membrane in various 
different ways, the object being to increase the extent of secreting surface within a 
given bulk. 
In the simplest form a single involution takes place, constituting a simple gland; 
this may be either in the form of an open tube (Fig. 77, a) or the walls of the tube 
may be dilated so as to form a saccule (Fig. 77, b). These are named the simple 
tubular or saccular glands. Or, instead of a short tube, the involution may be 
lengthened to a considerable extent, and then coiled up to occupy less space. This 
constitutes the simple convoluted tubular gland, an example of which may be seen in 
the sweat-glands of the skin (Fig. 77, c). 
If, instead of a single involution, secondary involutions take place from the pri- 
mary one, as in Fig. 77, D and E, the gland is then termed a compound one. These 
secondary involutions may assume either a saccular or tubular form, and so consti- 
tute the two subdivisions-the compound saccxdar or racemose gland, and the com- 
pound tubular. The racemose gland in its simplest form consists of a primary 
involution which forms a sort of duct, upon the extremity of which are found a 
number of secondary involutions, called saccules or alveoli, as in Brunner's glands 
(Fig. 77, d). But, again, in other instances the duct, instead of being simple, may 
divide into branches, and these again into other branches, and so on, each ultimate 
ramification terminating in a dilated cluster of saccules; and thus we may have the 
secreting surface almost indefinitely extended, as in the salivary glands (Fig. 77, e). 
In the compound tubular glands the division of the primary duct takes place in the 
same way as in the racemose glands, but the branches retain their tubular form, and 
do not terminate in saccular recesses, but become greatly lengthened out (Fig. 77, r). 
The best examples of this form of gland are to be found in the kidney and testicle. 
All these varieties of glands are produced by a more or less complicated involution GENERAL ANATOMY. 
98 
of a secreting membrane, and they are all identical in structure; that is to say, the 
saccules or tubes, as the case may be, are lined with cells, generally spheroidal or 
columnar in figure, and on their outer surface is an intimate plexus of capillary ves- 
sels. The secretion, whatever it may be, is eliminated by the cells from the blood, 
and is poured into the saccule or tube, and so finds its way out through the primary 
Fig. 77. 
Diagrammatic Plan of Varieties of Secreting Glands: A, simple gland: B, sacculated simple gland; C, simple 
convoluted tubular gland; D, E, racemose gland; F, compound tubular gland. 
involution on to the free surface of the secreting membrane. In addition, however, 
to these glands which are formed by an involution of the secreting membrane, there 
are some few others which are formed by a protrusion of the same structure, as in 
the vascular fringes of synovial membranes. This form of secreting structure is not 
nearly so frequently met with. Origin and Development of the Body. 
THE whole body is developed out of the ovum (Fig. 78) when fertilized by the 
spermatozoa. The ovum is merely a simple nucleated cell or collection of pro- 
toplasm, and the spermatozoa disappear when they have accomplished their mysteri- 
ous function. All the complicated changes by which the various intricate organs of 
the whole body are formed from one simple cell may be reduced to two general pro- 
cesses-viz. the segmentation or cleavage of cells, and their differentiation. The for- 
mer process consists in the splitting of the nucleus and its investing cell-wall, whereby 
the original cell is represented by two. The differentiation of cells is a term used 
to describe that unknown power or tendency impressed on cells-which, to all 
methods of examination now known, seem absolutely identical-whereby they grow 
into different forms; so that (to take the first instance which occurs in the growth 
of the embryo) the indifferent cells of the vascular area are differentiated, some of 
them into blood-globules, others into the solid tissue which forms the blood-vessels. 
The extreme complexity of the process of development renders it at all times difficult 
to describe it intelligibly, and still more so in a work like this, where adequate space 
and illustration can hardly be afforded, having respect to the main purpose of the 
Fig. 79. 
Fig. 78. 
'Lanapellucid a, 
-Ihscusprdui 
Cermnial vcslt), 
(rsrmvial spot's 
Human Ovum from a Middle-sized Follicle (magnified 
250 times): a, vitelline membrane or zona pellucida; 
b, external border of the yolk and internal border 
of the vitelline membrane ; c, germinal vesicle and 
germinal spot. 
Ovum of the Sow. 
work. I can only hope to render the leading features of the process tolerably plain, 
and must refer the reader who wishes to follow the various changes more minutely 
to the special works on the subject, and especially to the work of Foster and Balfour. 
Many of the statements which are accepted in human embryology are made only on 
the strength of experiments on the lower animals, direct observation on the human 
subject being impossible. 
The ovum is a small spheroidal body situated, in immature Graafian vesicles, 
near their centre, but in the mature ones in contact with the membrana granulosa,1 
at that part of the vesicle which projects from the surface of the ovary. The cells 
of the membrana granulosa are accumulated round the ovum in greater number 
than at any other part of the vesicle, forming a kind of granular zone, the discus 
proligerus. 
The human ovum (Fig. 79) is extremely minute, measuring of an inch in 
diameter. It is a cell consisting externally of a transparent envelope, the zona pel- 
lucida, or vitelline membrane. Within this, and in close contact with it, is the yolk 
or vitellus, imbedded in the substance of which is a small vesicular body, the germ- 
inal vesicle (vesicle of Purkinjef the nucleus of the cell; and this contains as its 
nucleus a small spot, the macula germinativa, or the spot of Wagner. 
The zona pellucida, or vitelline membrane, is a thick, colorless, transparent 
membrane which appears under the microscope as.a bright ring, bounded externally 
1 See the description of the Ovary. 
99 100 
GENERAL ANATOMY. 
and internally by a dark outline. It disappears, and is replaced by the chorion of 
the impregnated ovum. 
The yolk consists of granular protoplasm-i. e. of granules or globules of various 
sizes-imbedded in a more or less viscid fluid. The smaller granules are very 
minute; the larger granules, which are in the greatest number at the periphery of 
the yolk, resemble fat-globules. In the human ovum the number of granules is 
comparatively small. 
The germinal vesicle consists of a fine, transparent, structureless membrane 
containing a watery fluid, in which are occasionally found a few granules. It is 
iTwx an inch diameter, and in immature ova lies nearly in the centre 
of the yolk ; but as the ovum becomes developed it approaches the surface, and 
enlarges much less rapidly than the ovum itself. 
The germinal spot occupies that part of the periphery of the germinal vesicle 
which is nearest to the periphery of the yolk. It is opaque, of a yellow color, and 
finely granular in structure, measuring from to 5 0 of an inch. 
The phenomena attending the discharge of the ova from the Graafian vesicles, 
since they belong as much or more to the ordinary function of the ovary than to 
the general subject of the growth of the body, are described with the anatomy of 
the ovaries in the body of the work. 
It has long been known that the germinal vesicle disappears in the mature ova- 
rian ovum; but it has only recently been discovered that this disappearance is inti- 
mately connected with the formation of one or more peculiar bodies, the polar glob- 
ules of Robin, the origin of which has not been known, and also with the formation 
of another body, which appears to take a remarkable part in fecundation, and is 
named the female pronucleus. The order of the formation of these bodies from 
the germinal vesicle is briefly as follows: Usually before the rupture of the Graafian 
follicle, but after the ovum has become mature or ripe, a portion of the germinal 
vesicle is protruded outside the yolk, but still remains within the vitelline mem- 
brane ; this forms a small globular mass and constitutes the first polar globule. 
After a time, generally not till the ovum has entered the tube, a second protrusion 
of a portion of the germinal vesicle takes place, and forms a second polar globule. 
We have thus about two-thirds of the germinal vesicle extruded from the yolk, and 
Fig. 80. 
Fertilization of the Ovum of an Echinoderm: s, spermatozoon: m. pr., male pronucleus; f. pr., female pronu- 
cleus ; 1, accession of a spermatozoon to the periphery of the vitellus; 2, its penetration ; 3, transformation 
of the head of the spermatozoon into the male pronucleus; 4, 5, blending of the male and female pronuclei 
(from Quain's Anatomy, Selenka). 
about one-third remaining behind; and upon the ejection of each of these bodies a 
visible shrinking of the yolk takes place. The portion of the germinal vesicle which 
remains behind recedes from the surface toward the centre of the yolk and assumes 
a spherical form, and is now termed the female pronucleus. All these changes, it 
must be understood, occur at each expulsion of an ovum, and are quite independent 
of fecundation. THE HUMAN OVUM. 
101 
The first changes in the ovum which take place at the time of conception appear 
io be as follows: One or more spermatozoa penetrate the ovum, and come into con- 
tact with the yolk and with the portion of the germinal vesicle remaining in the 
yolk. It seems as if this normally occurs in the Fallopian tube,1 but abnormally 
it may even take place in the peritoneal cavity. One spermatozoon, in advance of 
all the rest, becomes buried in the yolk, the tail disappears, and the head, a sort of 
nuclear body, constitutes the male pronucleus. This gradually approaches the female 
pronucleus, which by this time is situated in the centre of the yolk. As soon as they 
come into contact they fuse into one, and thus fecundation is effected (Fig. 80). It 
is believed by most physiologists that one spermatozoon is sufficient for fecundation; 
but in all probability several spermatozoa, as a rule, penetrate the yolk and undergo 
the same process of conversion into male nuclei, reach the female pronucleus, and 
fuse with it.2 [This last is probably not the case.] 
The first result of the fertilization of the ovum is a cleavage or fission of its sub- 
stance, which is first cleft into two masses, then into four, and so on, until at length 
Fig. 81. 
Four Diagrams to show the Division of the Yolk. The ovum is surrounded by spermatozoa. The clear 
corpuscles (polar globules of Robin) are seen in the first two. 
a mulberry-like agglomeration of nucleated cells results (Fig. 81). These cells are 
sometimes termed vitelline spheres. 
The manner in which segmentation occurs is somewhat peculiar. The two spheres 
resulting from the first cleavage are of unequal size. One, which for the sake of 
distinction we will call the upper or epiblastic cell, is larger than the other, the lower 
or hypoblastic cell, and after they have divided three or four times, the rate of 
cleavage in the spheres derived from the upper or epiblastic segment becomes more 
rapid than in those derived from the lower or hypoblastic segment. In addition to 
this, the spheres derived from the upper segment have a tendency to spread out over 
and enclose those from the lower segment; so that by about the ninth or tenth 
division there is an external layer of spheres derived from the primary upper or epi- 
blastic segment surrounding and almost enclosing a mass of spheres, which in con- 
sequence of their diminished rate of cleavage are fewer in number and larger in 
size, derived from the primary lower or hypoblastic segment (Fig. 82, a). Fluid 
collects between the two sets of spheres, except at one part, where they remain in 
contact, and the ovum is converted into a sac formed by a layer of spheres derived 
from the upper primary segment, and containing at one part another mass of spheres 
derived from the lower primary segment (Fig. 82, b). The inner cells are rather 
more granular than the outer, beneath which they gradually spread, becoming applied 
over a part of their inner surface in a single layer; so that the cavity is afterward 
enclosed more or less completely in a double layer of cells. 
The ultimate destination of the outermost complete layer of spheres is at present 
doubtful. By some they are believed to be transitory, and gradually to disappear in 
the course of the formation of the various layers of the blastodermic membrane; by 
others it is thought that they form the outer layer (epiblast) of this membrane. 
1 Many physiologists, as Bischoff and Dr. M. Barry, taught that the ovum is fecundated in the 
ovary, but the reasoning of Dr. Allen Thomson appears very cogent in proving that the usual spot 
at which the spermatozoa meet the ovum is in the tube, down which it slowly travels to the uterus, 
in its course becoming surrounded by an albuminous envelope derived from the walls of the tube. 
2 If the student refers to the development of the generative organs, he will find that the ovum 
of the female and the spermatozoon of the male are derived from fundamentally the same structures, 
and therefore their fusion is the union of two elements of very similar morphological value. 102 
GENERAL ANATOMY. 
Adopting the latter and more general view, the ovum would consist of a cavity sun. 
rounded by (1) a layer of cells completely lining the interior of the vitelline mem- 
brane, and (2) by a second layer internal to these and partially lining the interior 
Fig. 82. 
Ovum of the Rabbit at the End of the Process of Segmentation: ep, e-piblast; hy, primitive hypoblast; bp, place 
where the epiblast has not yet grown over the hypoblast (from Balfour, after Ed. van Beneden). 
of the outer layer, both sets of cells derived from the segmentation of the ovum. 
The double layer of cells is called the 'c blastodermic membrane, " the outer layer 
being termed the "epiblast," and the inner the "hypoblast." 
At first the area of the blastodermic membrane, which consists of both the inner 
and outer layers of cells, is a small disk 
in which the first traces of the embryo 
are seen ; hence it is called the germinal 
disk or area germinativa (Fig. 83). The 
first trace of the embryo appears as a 
faint streak [at the posterior end of the 
area germinativa], called the primitive 
trace. After the formation of the prim- 
itive trace, but previous to the appear- 
ance of the next parts of the embryo 
presently to be described-viz. the 
laminae dorsales and the notochord- 
the blastodermic membrane consists of 
only two layers, the epiblast and hypo- 
blast, but during the formation of these 
structures a third layer has made its 
appearance. This is the mesoblast, and 
is situated between the other two (Fig. 
84). As to the precise origin of this 
third layer considerable difference of 
opinion exists. According to some 
embryologists, it is formed entirely by 
proliferation of cells belonging to the epiblastic layer; according to others, it is 
formed by a splitting of the hypoblast, or, at all events, a differentiation into a 
central layer of mesoblastic cells and a lower layer of hypoblastic cells. But in 
whichever way this third stratum may be formed, the blastodermic membrane even- 
tually consists of three layers-the external, which used to be called the serous layer, 
but is now more commonly termed the epiblast; the internal, the mucous layer or 
hypoblast; and the middle, believed by most writers to be originally developed by 
cleavage from the hypoblast, which is now usually called the mesoblast, but which 
was formerly named the "vascular layer." 
The epiblast is mainly concerned in the formation of the external cuticle and of 
the nervous centres. The epidermis of the body and all the involutions of the epi- 
[Fig. 83. 
Rabbit's Ovum between seventy and ninety hours after 
impregnation: bv, cavity of blastodermic vesicle; ep, 
epiblast; hy, primitive hypoblast; zp, zona pellucida 
(Foster and Balfour).] FIRST RUDIMENTS OF THE EMBRYO. 
103 
dermis in the ducts of [superficial] 
glands, as the mammae, as well as 
the brain, the spinal cord, and part 
of the eye, which is directly formed 
from the brain, and portions of the 
nose and ear, are developed from it. 
The external layer of the amnion is 
also formed from the epiblast, and 
also a portion of the chorion. 
The hypoblast is mainly con- 
cerned in forming the internal epi- 
thelium-viz. that of the whole ali- 
mentary passages except the mouth 
and a small portion of the rectum 
near the anus (which are formed 
by an involution of the integument 
[epiblast]); that of the respiratory 
tract, which is originally an offset from the alimentary canal; and the epithelium of 
all the glandular organs which open into the intestinal tract. The hypoblast forms 
also the deeper layer of the umbilical vesicle and allantois. 
All the rest of the embryo is formed from the mesoblast-viz. all the vascular 
and locomotive system, the cutis, all the connective tissues, the nerves1 and the 
genito-urinary organs, through the Wolffian bodies and other temporary foetal struc- 
tures. The vascular system of the foetus extends to the yolk and the maternal parts 
along the umbilical vesicle and allantois, so that the greater part of these bodies and 
the outer layer of the amnion are also formed out of the mesoblast. The foetal por- 
tion of the placenta, being essentially a vascular structure, is also developed from the 
mesoblast. 
First Rudiments of the Embryo (Figs. 85 and 86).-The primitive trace, 
alluded to above as appearing in the area germinativa, is a very transitory struc- 
ture, which marks the direction of the embryonic axis, and is gradually lost in 
consequence of its place becoming occupied by the rudimentary spinal column [and 
embryonic axis]. 
The first real approach toward a definite form in the embryo is made (1) by the 
development of the rudimentary spinal column; (2) by the cleavage of the middle 
layer of the blastodermic membrane from which a part of that column is derived; 
and (3) by the incurvation of the column at its cephalic end to form the brain and 
brain-case. 
First, a growth and heaping up of the cells of the epiblast or outer layer take 
place. This commences in the anterior part of the area germinativa and extends in 
the same direction as the primitive trace, gradually occupying its position until this 
latter is lost at the caudal extremity of the embryo (Fig. 87). This heaping up of 
the epiblast gives rise to a longitudinal groove clown its centre, in consequence of 
the manner in which the cells of the epiblast are heaped up into two [longitudinal] 
ridges, with a furrow between them, so that the sides and base of the groove are 
formed of epiblastic cells (Fig. 88, a). The groove becomes deeper and deeper in 
consequence of the further heaping up of the cells to form the ridge on either side. 
In this way the ridges eventually become two plates, the lamince dorsales or medul- 
lary plates, which finally coalesce, and thus form a closed tube, the neural canal, 
lined by epiblast and having a covering of the same membrane (Fig. 88). This 
coalescence first takes place in the middle of the embryo, then toward the cephalic 
end, and lastly at the caudal extremity. The lining of this tube is developed into 
the nervous centres, the covering into the epidermis of the back and head. The 
Fig. 84. 
Section of a Blastoderm, at right angles to the long axis of 
the embryo, near its middle, after eight hours' incubation 
(from Foster and Balfour): a, epiblast formed of two layers 
of cells; b, mesoblast thickened below the primitive groove; 
c, hypoblast formed of one layer of flattened cells; pr, 
primitive groove; me, mesoblast cell; bd, formative cells in 
the so-called segmentation or subgerminal cavity. (The 
line of separation between the epiblast and mesoblast below 
the primitive groove is too strongly marked in the figure.) 
1 In the spinal nerves the part in connection with the cord, including the ganglion, is formed from 
mesoblast, according to the most recent observation. [The spinal nerves do not arise as here stated, 
but are developed as outgrowths from the spinal cord. They are therefore of epiblastic, rather than 
of mesoblastic, origin.] 104 
GENERAL ANATOMY. 
Fig. 85.1 
.Diagrams to show the Development of the Three Layers of the Blastodermic [vesicle or] Membrane in transverse 
sections: A, portion of the ovum with the zona pellucida and the germinal area. B, C, D, E, F, G, different 
stages of development; o, umbilical vesicle; a, amnion; i, intestine; p, peritoneal cavity, bounded by the 
splanchno-pleural and somato-pleural layers of mesoblast; 1, vitelline membrane; 2, external blastodermic 
layer [epiblast]: 3, middle layer [mesoblast]; 4, internal layer [hypoblast]; 5, medullary laminae and groove; 
5', medullary canal; 6, epidermic laminae; 7, lateral flexures of the amnion; 7', the same almost in contact: 
8, internal epithelial layer of the amnion; 9, epidermis of the embryo; 10, chorda dorsalis; 11, vertebral 
laminae; 12, protovertebrae proper; 18, muscular laminae; 14, lateral laminae; 15, fibro-intestinal laminae; 16, 
cutaneous laminae; 17, internal fibrous layer of the umbilical vesicle; 18, muscular laminae extending to 
meet the cutaneous; 19, external layer of the cutaneous laminae; 20, internal layer of the same; 21, mesentery; 
22, fibrous layer of the intestine. 
1 The dotted lines indicate the parts belonging to the internal blastodermic layer; the plain lines those 
belonging to the middle; the interrupted lines those belonging to the external. The embryo has been repre- 
sented, in this and the following diagram, lying on its back. The natural position is generally assumed to be 
the reverse. , DEVELOPMENT OF THE BLASTODERM. 
105 
Fig. 86.1 
Diagrams to show the Development of the Three Blastodermic Layers in antero-posterior sections : A, portion 
of ovum with the vitelline membrane and germinal area. B, C, D, E, F, various stages of development. G, 
ovum in the uterus and formation of decidua; 1, vitelline membrane; 2, external blastodermic layer 
[epiblast]; 2', vesicula serosa; 3, middle blastodermic layer [mesoblast]; 4, internal layer [hypoblast]; 5, the 
future embryo; 6, cephalic flexure of the amnion; 7, caudal flexure; 8, spot where the amnion and vesicula 
serosa are continuous; 8', posterior umbilicus; 9, cardiac cavity; 10, external fibrous layer of the umbilical 
vesicle; 11, external fibrous layer of the amnion; 12, internal layer of the blastoderm forming the intestine; 
13,14, external layer of the allantois, extending to the inner surface of the vesicula serosa; 15, the same now 
completely applied to the inner surface of the vesicula serosa; 16, umbilical cord; 17, umbilical vessels; 18, 
amnion; 19, chorion; 20, foetal placenta ; 21, mucous membrane of uterus • 22, maternal placenta; 23, decidua 
reflexa; 24, muscular wall of uterus. 
1 The same note applies to this as to the preceding diagram. 106 
GENERAL ANATOMY. 
cephalic extremity of the neural canal is soon seen to be more dilated than the rest, 
and to present constrictions dividing it imperfectly into three chambers: the brain 
is developed from this dilated portion; the spinal cord takes its origin from the 
remainder of the tube. Below the neural canal the mesoblast lies, and from this 
Fig. 88. 
Fig. 87. 
Transverse Sections through the Em- 
bryo Chick, before and some time after 
the closure of the medullary canal, to 
show the upward and downward in- 
flections of the blastoderm (after Re- 
mak). A, at the end of the first day : 1, 
notochord; 2, primitive groove in the 
medullary canal; 3. edge of the dorsal 
lamina; 4, corneous layer or epiblast; 
5, mesoblast divided in its inner part; 
6, hypoblast or epithelial layer; 7, sec- 
tion of protovertebral segment. 
B, on the third day in the lumbar region : 
1, notochord in its sheath; 2, medul- 
lary canal, now closed in ; 3, section of 
the medullary substance of the spinal 
cord; 4, corneous layer; 5, somato- 
pleure of the mesoblast; 5', splanch- 
nopleure (one figure is placed in the 
pleuro-peritoneal cavity); 6, layers of 
hypoblast in the intestines, spreading 
also over the yolk; 4 X 5, part of the 
fold of the amnion formed by epiblast 
and somatopleure. 
Embryonic Area of the Ovum of a Rabbit at the Seventh Day: a<j, 
embryonic area; o, o, region of the blastodermic vesicle imme- 
diately surrounding the embryonic area; pr, primitive streak; 
rf, medullary groove (from Kolliker). 
are developed (1) a continuous rod-shaped body lying below the primitive groove, 
called the notochord or chorda, dorsalis ;1 (2) on either side a row of well-defined, 
dark, square segments or masses, separated by clear, transverse intervals, called the 
protovertebrce or protovertebral somites. These first make their appearance in the 
region which afterward becomes the neck, then farther forward toward the head, and 
afterward extend along the body. They are developed from mesoblastic cells which 
form a thick longitudinal column on either side of the notochord, and [which become] 
separated from the rest of the mesoblastic layer. The remainder of the mesoblast 
forms a flattened layer of cells between the epi- and hypoblast, and, as will presently 
be seen, divides into two plates, leaving an interval between them. The longitu- 
dinal column, on the other hand, undergoes a series of transverse segmentations, and 
so becomes converted into the quadrilateral protovertebrm. These bodies, as will be 
explained hereafter, are not the same as the permanent vertebrae, but they are differ- 
entiated, partly into the vertebrae and partly into the muscles and true skin. Just 
outside the two series of protovertebrae the mesoblast splits into two layers: the 
upper, or that covered by epiblast, is called the somatopleure, and the lower, lined by 
hypoblast, the splanchnopleure (Fig. 88 B, 5-5'). From the former the skeleton, 
muscles, and true skin of the external parts of the body are derived; from the lat- 
ter, the muscular and other mesoblastic portions of the viscera. The space between 
1 Some doubt appears to exist as to whether the notochord is not developed from the hypoblast 
(Balfour). [It is now generally admitted that the notochord arises from the hypoblast.] DEVELOPMENT OF THE EMBRYO. 
107 
them is the common pleuro-peritoneal cavity. Whilst the parietes of the body are 
still unclosed, this common pleuro-peritoneal cavity is continuous with the space 
between the amnion and chorion, as seen in Fig. 85, F. The embryo, which at first 
seems to be a mere streak, extends 
longitudinally and laterally. As 
it grows forward the cephalic end 
becomes remarkably curved on it- 
self (cephalic flexure), and a small- 
er but distinct flexure takes place 
at its hinder end (caudal flexure). 
At the same time the sides of the 
embryo grow and curve toward 
each other ; so that the embryo is 
aptly compared to a canoe turned 
over (Fig. 89). In consequence 
of this incurving of the embryo, 
both in an antero-posterior and 
a lateral direction, the original 
ovum, with the three layers de- 
rived from its cleavage to form 
the vesicular blastodermic mem- 
brane, is converted into an hour- 
glass shape with two unequal 
globes. The smaller globe is 
formed by the part of the blasto- 
dermic membrane (area germina- 
tiva), which has already under- 
gone certain changes in the for- 
mation of the embryo, and con- 
stitutes the part which has been 
compared to a canoe. The larger globe is called the yolk-sac or umbilical vesicle, 
and is formed by the rest of the blastodermic membrane-i. e. that part which is 
Fig. 89. 
Diagrammatic Section through the Ovum of a Mammal in the 
Long Axis of the Embryo: e, the cranio-vertebral axis; i, i, 
the cephalic and caudal portions of the primitive alimentary 
canal; a, the amnion; a', the point of reflection into the false 
amnion; v, yolk-sac, communicating with the middle part of 
the intestine by vi, the vitello-intestinal duct; u; the allantois. 
The ovum is surrounded externally by the villous chorion. 
Fig. 90. 
YoTk Sac 
-Npiblast 
.Body 
of 
Nrn.hr/fo 
-Sjilanchrtoplcurc 
Somato-pleare 
Plcuro-peritorocal cavity 
Notochord'' 
Neural cancel' 
Diagrammatic Section of Embryo, showing the formation of the umbilical vesicle. 
not concerned in the formation of the area germinativa. The two freely communi- 
cate through the constriction which is the site of the future umbilicus, and through 108 
GENERAL ANATOMY. 
this constriction the internal layer of the blastodermic membrane (the hypoblast) 
and the innermost of the two layers into which, as has been already stated, the 
mesoblast divides-viz. the splanchnopleure-pass out, the incurving have only 
involved the somato-pleural layer of the mesoblast and the epiblast (Fig. 90). The 
umbilical vesicle is, therefore, at first a mere part of the general cavity of the 
blastodermic vesicle, partly enclosed by the embryo; but as the latter grows round 
on all sides toward the umbilical aperture, the umbilical vesicle becomes distin- 
guished into two portions. One lies inside the embryo, and eventually forms a part 
of the intestinal cavity (out of which also, as will hereafter be seen, the bladder is 
developed). The other lies external to the embryo, and remains, therefore, [for a 
time] a part of what is, in a more restricted sense, the ovum. The two parts are 
almost separated from each other by the meeting of the abdominal walls of the 
embryo at the umbilicus, through which they still communicate by a passage, the 
omphalo-mesenteric duct, the destination of which will be pointed out presently. 
The extra-embryonic portion is of small importance and very temporary duration, 
in the human subject. It is for the purpose of supplying nutrition to the embryo 
during the very earliest period, before it can obtain it from the uterine sinuses of 
the mother. In the oviparous animals, however, where no supply of nutrition can 
be obtained from the mother, since the egg is entirely separated from her, the yolk- 
Fig. 91. 
Magnified View of the Human Embryo of Four Weeks, with the membranes opened (from Leishman, after 
Coste): y, the umbilical vesicle with the omphalo-mesenteric vessels, ®, and its long tubular attachment to 
the intestine; c, the villi of the chorion; m, the amnion opened; w, cul-de-sac of the allantois, and on each 
side of this the umbilical vessels passing out to the chorion; a, in the embryo, the eye ; e, the ear-vesicle; h, 
the heart: I, the liver;.o, the upper, p, the lower limb: w, Wolffian body, by the side of which are the mes- 
entery and intestine. The Wolffian duct and tubes are not represented. 
sac is large and of great importance, as it supplies nutrition to the chick during the 
whole of foetation. Vessels developed in the middle blastodermic layer soon cover 
the umbilical vesicle, forming the vascular area, the chief vessels of which are the 
omphalo-mesenteric, two in number (Fig. 91). The vessels of this area appear to THE AMNION. 
109 
absorb the fluid of the umbilical vesicle, which as. the fluid is absorbed dries up and 
has no further function. The activity of the umbilical vesicle ceases about the fifth 
or sixth week, at the same time that the allantois, which is the great bond of vascu- 
lar connection between the embryo and the uterine tissues, is formed. In fact, the 
umbilical vesicle provides for the nutrition of the foetus from the ovum itself, while 
the allantois is the channel whereby it is nourished from the uterine tissues. The 
umbilical vesicle, containing fluid, remains visible, however, up to the fourth or fifth 
month, with its pedicle and the omphalo-mesenteric vessels. The latter vessels 
become atrophied as the functional activity of the body with which they are con- 
nected ceases. 
So far we have traced (1) the segmentation or cleavage of the yolk into a num- 
ber of nucleated cells-"vitelline spheres;" (2) tlie accumulation of fluid within 
the ovum, and the arrangement of the vitelline spheres around the fluid on the 
internal surface of the vitelline membrane, forming a second membrane, the 
"blastodermic membrane;" (3) the separation of the blastodermic membrane into 
three layers, named, from within outward, the "hypoblast," the "mesoblast," and 
the "epiblast;" (4) the formation of an elongated, oval-shaped disk called the 
"area germinativa;" (5) the appearance in the centre of the area germinativa of 
.a delicate line or furrow, running longitudinally and called the "primitive trace;" 
(6) the formation of a distinct groove in the situation of this primitive trace, caused 
by the heaping-up of the cells on either side of it, so as to form two longitudinal 
ridges called the "laminae dorsales;" (7) the increase and incurvation of these 
laminae dorsales until they meet behind, enclosing a canal lined by epiblast: the 
-canal is the neural canal, and from the epiblast which lines it the nervous centres 
are developed; (8) the formation, in the mesoblast immediately under this canal, 
of a continuous rod-shaped body, the "chorda dorsalis" or "notochord;" (9) the 
formation, also from the mesoblast, on either side of the notochord, of a longitu- 
dinal column divided into a number of square segments, the "protovertebrce (10) 
the splitting of the mesoblast, external to the protovertebrae, into two layers-the 
outer, called the "somatopleure," lined externally by the epiblast; the inner, called 
the " splanchnopleure," lined internally by the hypoblast, a space being left between 
the two, which forms the " pleuro-peritoneal cavity ;" (11) the curving of the embryo 
•on itself, both longitudinally and laterally, so as to be comparable to a canoe, the 
walls being formed of all three layers of the blastodermic membrane and the well 
of the canoe-that is, the body-cavity of the embryo opening into the cavity of the 
yolk-sac; (12) a portion of the yolk-sac now lying in the body-cavity of the embryo, 
and a portion outside it, the two communicating by a duct, the " omphalo-mesen- 
teric " duct. The portion of the yolk-sac external to the body-cavity is now termed 
the umbilical vesicle, and provides nutrition to the embryo until such time as the 
allantois is formed, vessels developed from the middle blastodermic layer ramifying 
over it and gradually absorbing its contents.1 
The next step toward a clear understanding of the development of the embryo 
is to have a proper conception of the manner in which the membranes enveloping 
the foetus are formed. 
The membranes investing the foetus are the amnion, the chorion, and the 
decidua. The two former are developed from foetal structures, and are proper to 
the foetus; the latter is formed in the uterus, and is derived from the maternal 
structures. 
The Amnion.-The amnion is the membrane which immediately surrounds the 
embryo. It is of small size at first, but increases considerably toward the middle 
of pregnancy, as the foetus acquires the power of independent movement. It exists 
only in reptiles, birds, and mammals, which are hence called " Amniota," but is 
absent in amphibia and fishes. It is formed thus: At or near the extremities of 
the incurved foetus-that is to say, at the point of constriction of the blastodermic 
membrane, where the portion which has undergone changes to form the body of the 
r1 It is very doubtful if any considerable amount of nutriment is supplied to the embryo from the 
yolk-sac at any time.] 110 
GENERAL ANATOMY. 
embryo joins the part devoted to the formation of the umbilical vesicle-an inflec- 
tion of the epiblast and outer layer of the mesoblast, which have become separated 
from the inner layer of the mesoblast and hypoblast by the formation of the pleuro- 
peritoneal cavity, takes place (Fig. 85, d 7). These inflections or backward folds 
commence first at the cephalic extremity, and subsequently at the caudal end and 
sides, and deepen more and more by growing up over the back of the embryo, until 
they, gradually approaching, meet one another (Fig. 85, E 7). After they come in 
contact they fuse together, and the septum between them disappears; so that the 
inner layer of the cephalic fold becomes continuous with the inner layer of the cau- 
dal fold, and the outer with the outer (Fig. 85, F 7'). Thus we have two mem- 
branes, one formed by the inner layer of the fold-the true amnion-which encloses 
a space over the back of the embryo-the amniotic cavity (Fig. 85, F and G, «)- 
containing a clear fluid, the liquor amnii.x The other, the outer layer of the fold 
-the false amnion-lines the internal surface of the original vitelline membrane. 
Between the two is an interval, which of course communicates with the pleuro-peri- 
toneal cavity (Fig. 89). The true amnion-or, as it is usually called, the amnion 
-is formed of two layers, derived respectively from the epiblast and from the pari- 
etal layer of the mesoblast. The one from the epiblast consists of nucleated cells; 
the other, from the mesoblast, has a fibrous and, according to some embryologists, 
a muscular structure; at all events, it possesses rhe power of rhythmic contraction 
during life. In some animals this layer is vascular. 
The amnion is at first in close contact with the surface of the body of the 
embryo, but about the fourth or fifth week fluid begins to accumulate, and thus 
separates the two. The quantity steadily increases up to about the sixth month 
of pregnancy, after which it diminishes somewhat. The use of the liquor amnii is 
believed to be chiefly to allow of the movements of the foetus in the later stages of 
pregnancy, though it no doubt serves other purposes also. It contains about 1 per 
cent, of solid matter, chiefly albumen, with traces of urea, the latter probably derived 
from the urinary secretion of the foetus. 
The Chorion.-The chorion is rather a complex membrane, made up essentially 
of two parts: first, of the membranes of the ovum external to the pleuro-peritoneal 
cavity-that is to say, of the vitelline membrane and false amnion ; and, secondly, 
of a diverticulum of the splanchnopleure [and hypoblast pushed out into] the pleuro- 
peritoneal cavity. This diverticulum is called the allantois. 
1. The portion of the chorion which is formed from the membranes of the ovum 
external to the pleuroperitoneal cavity. We have seen that in the formation of the 
amnion we had two layers formed out of a reduplication of the epiblast and outer 
layer of the mesoblast: one-the true amnion-which surrounds the embryo and 
encloses a cavity between it and the embryo-the amniotic cavity; and secondly, 
the false amnion, which lies in apposition with the internal surface of the vitelline 
membrane, and is continuous at its periphery with the original epiblast and somato- 
pleural layer of the mesoblast which did not enter into the formation of the area 
germinativa; and that between these two layers there is a space (which must not be 
confounded with the amniotic cavity) which communicates with the pleuro-perito- 
neal space, and, according to Dalton, contains a semifluid, gelatinous material. 
The external part of the chorion is formed out of the vitelline membrane with the 
false amnion, and its peripheral continuation with the external layers of the blasto- 
derm ; but the exact share which the three layers take in its formation is at present 
uncertain. By some embryologists it is believed that the vitelline membrane during 
the rapid growth of the ovum becomes attenuated, and finally lost; by others it is 
thought that it combines with the other layers to form the chorion. But, whichever 
is true, at a very early period of gestation cellular processes or fringes grow outward 
1 The student should be careful not to confound this cavity with that formed between the true 
and false amnion, which communicates with the pleuro-peritoneal cavity of the embryo. This lat- 
ter space ought with more propriety to be called the " amniotic cavity," since it is contained between 
the layers of the amnion; whereas the so-called amniotic cavity is not really between the layers of 
the amnion at all, but between the inner layer of the amnion and the body of the embryo. THE ALLANTOIS AND DECIDUA. 
111 
from the external surface of the vitelline membrane, or, if this has disappeared, from 
the outer layer of the blastoderm, which have been likened by Dalton to tufts of 
sea-weed. They are at first destitute of vessels and are of simple cellular structure. 
These fringes, or villi as they subsequently become, cover at first the whole surface 
of the chorion; but as development progresses and the placenta by which the extent 
of the attachment of the ovum to the uterine walls is to be limited is about to be 
formed, the villi are not further developed over the rest of the chorion, but are con- 
fined to that part only which is to form the foetal portion of the placenta. They 
may, however, be recognized all over the chorion as abortive processes during the 
whole of foetal gestation. 
2. The Allantois.-This structure is derived from the layers of the blastodermic 
membrane which are internal to the pleuro-peritoneal space, being formed by the 
projection of a hollow bud of that part of the hypoblast and splanchnopleure which 
is contained in the body-cavity of the embryo, and which, as we have before stated, 
is intended for the formation of the intestinal canal (Fig. 89, w).1 It extends into 
and through the pleuro-peritoneal space, into the cavity between the true and false 
amnion, until it meets the latter, over the internal surface of which it spreads. In 
this diverticulum two arteries and two veins (the allantoic vessels) are developed. The 
arteries are in the first instance branches of the two primary divisions of the abdom- 
inal aorta, but subsequently, when the two aortas coalesce, they become branches 
of the hypogastric arteries. The veins join the veins of the yolk-sac and form the 
umbilical veins. When the allantois meets the chorion, branches from these allantoic 
vessels permeate the cellular tufts or fringes previously described as growing from 
the outer surface of the false amnion, and convert them into vascular villi, which 
eventually form the foetal portion of the placenta2 (Fig. 91, c). The allantois is the 
chief agent of the early circulation-i. e. the duct or tract along which the vessels 
extend which convey the. blood of the embryo to the foetal chorion, where it is 
exposed to the influence of the maternal blood circulating in the decidua or uterine 
portion of the placenta, from which it imbibes the materials of nutrition, and to 
which it gives up effete materials, the removal of which is necessary for its purifica- 
tion. In some animals the allantois is a hollow projection, and is usually styled the 
allantoic vesicle ; but in most mammals, and especially in man, the external or meso- 
blastic element undergoes great development, while the internal or hypoblastic ele- 
ment undergoes little increase beyond the body of the embryo, so that it is very 
doubtful whether any cavity exists in the allantois beyond the limits of the umbilicus, 
or whether it does not rather consist of a solid mass of material derived from the 
mesoblastic tissue.3 A portion of the allantoic vesicle within the body-cavity is 
eventually destined to form the bladder, while the remainder forms an impervious 
cord, the urachus, stretching from the summit of the bladder to the umbilicus. The 
part external to the foetus forms the umbilical cord, by which the foetus is connected 
with the villi of the chorion, which eventually form the foetal portion of the placenta. 
The Decidua.-The growth of the chorion and placenta can only be understood 
by tracing the formation of the decidua. 
The decidua (Figs. 86, 92) is formed from the mucous membrane of the uterus. 
Even before the arrival of the fecundated ovum in the uterus the mucous membrane 
of the latter is vascular and tumid, and when the ovum has reached the uterus it 
becomes imbedded in the folds of the mucous membrane, which grow up around it, 
and finally completely encircle it, so as to cover it in entirely and exclude it from 
the uterine cavity. Thus two portions of the uterine mucous membrane (decidua) 
1 [I would prefer to state this as follows: This structure is developed as a hollow ventral outgrowth 
of the hinder portion of the primitive intestine of the embryo; its walls consist of the hypoblastic 
and splanchno-pleural layers (Fig. 89, «).] 
2 In some animals, some of the vessels of the villi of the chorion are derived from the yolk-sac; 
that is, the omphalo-mesenteric vessels. 
3 Indeed, it would appear, from the researches of His, that in the human embryo not only is the 
allantois formed unusually early, as is admitted by all, but in an altogether exceptional manner, not 
consisting of an outgrowth from the portion of the splanchnopleure engaged in the formation of the 
alimentary canal, but being present from a very early period as a stalk connecting the posterior 
extremity of the embryo with the chorion. 112 
GENERAL ANATOMY. 
are formed-viz. that which coats the muscular wall of the uterus, decidua vera, 
and that which is reflected over the ovum, decidua reflexa. The decidua vera at 
the os internum and at the openings of the Fallopian tubes is continuous with the 
lining membrane of these canals, the thickening of the original mucous membrane 
of the uterus which converts it into decidua abruptly ceasing at these points. The 
[Fig. 92. 
diagrammatic Section of the Human Uterus, with Embryo in situ, showing Relations of Placenta, etc.: al, 
allantoic stalk ; am, true amnion; the part shaded horizontally, between the amnion and the embryo, is the 
amnionic cavity; c, cavity of uterus; c', plug of mucus in cervix uteri; ch, chorion; dr, decidua reflexa; ds, 
decidua serotina: dv, decidua vera; i, intestine of embryo; u, umbilical or allantoic arteries; y, yolk-sac; 
y', yolk-stalk (Longet).] 
neck of the uterus after conception is closed by a plug of mucus. The decidua vera 
is perforated by the openings formed by the enlarged uterine glands, which become 
much hypertrophied and developed into tortuous tubes. It contains at a later period 
numerous arteries and venous channels continuous with the uterine sinuses, and it is 
from it that the uterine part of the placenta is developed. The portion of the decidua 
vera which takes part in the formation of the placenta is called the decidua serotina 
(Fig. 92, cZs). 
The decidua reflexa (Fig. 92, dr) is shaggy on its outer aspect, but smooth within. 
The vessels which it Contains at first disappear after about the third month. About 
the fifth or sixth month the space between the two layers of the decidua disappears, 
and toward the end of pregnancy the decidua reflexa is transformed into a thin yel- 
lowish membrane which constitutes the external envelope of the ovum. DEVELOPMENT OF THE SPINE. 
113 
Much additional interest has been given to the physiology of the decidua by the 
fact, which seems to be now established by the researches of Dr. John Williams, that 
every discharge of an ovum, whether impregnated or not, is, as a rule, accompanied 
by the formation of a decidua, and that the essence of menstruation consists in the 
separation of a decidual layer of the mucous membrane from the uterus ; while in 
the case of pregnancy there is no exfoliation of the membrane, but, on the contrary, 
it undergoes further development in the manner described above. 
The Placenta is the organ by which the connection between the foetus and 
mother is maintained. It therefore subserves the purposes both of circulation and 
respiration. It is formed of two parts, as already shown-viz. the maternal portion, 
which is developed out of the decidua vera (serotina), and the foetal portion, formed 
out of the villi of the chorion. Its shape in the human subject is that of a disk, one 
side of which adheres to the uterine wall, while the other is covered by the amnion. 
The villi of the chorion (or uterine placenta) gradually enlarge, forming large pro- 
jections-cotyledons-which each contain the ramifications of vessels communicating 
with the umbilical (allantoic) arteries and veins of the foetus. These vascular tufts 
are covered with epithelium, and project into corresponding depressions in the 
mucous membrane (decidua vera) of the uterine wall. The maternal portion of the 
placenta consists of a large number of sinuses formed by an enlargement of the ves- 
sels of the uterine wall. These bring the uterine blood into close proximity with 
the villi of the foetal placenta, which dip into the sinuses. The interchange of fluids 
necessary for the growth of the foetus and for the depuration of the blood takes place 
through the walls of the villi, but there is no direct continuity between the maternal 
and foetal vessels. The foetal vessels form tufts of capillaries, the blood from which 
is returned by small veins which end in tributaries of the umbilical vein. The mater- 
nal arteries open into spaces somewhat after the manner of the arteries of the erectile 
tissues. These spaces communicate with a plexus of veins which anastomose freely 
with one another and give rise, at the edge of the placenta, to a venous channel 
which runs around its whole circumference-the placental sinus. 
The Umbilical Cord appears about the end of the fifth month after pregnancy. 
It consists of the coils of two arteries (umbilical, originally allantoic) and a single 
vein, united together by a gelatinous tissue (jelly of Wharton). There are originally 
two umbilical veins, but one of these vessels becomes obliterated, as do also the two 
omphalo-mesenteric arteries and veins and the duct of the umbilical vesicle, all of 
which are originally contained in the rudimentary cord. The permanent structures 
of the cord are therefore furnished by the allantois. 
In this manner the human embryo eventually becomes surrounded with three 
membranes: (1) the amnion, derived from the outer layer of the mesoblast and the 
epiblast; (2) the chorion, formed most probably by three layers-the allantois (which 
is derived from the inner layer of the mesoblast and hypoblast), the false amnion, 
and perhaps the vitelline membrane; and (3) the decidua, derived from the mucous 
membrane of the uterus. 
Development of the Embryo Proper.-The further development of the em- 
bryo will, perhaps, be better understood if we follow, as briefly as possible, the prin- 
cipal facts relating to the chief parts of which the body consists-viz. the spine, the 
cranium, the pharyngeal cavity, mouth, etc., the nervous centres, the organs of the 
senses, the circulatory system, the alimentary canal and its appendages, the organs 
of respiration, and the genito-urinary organs.1 The reader is also referred to the 
chronological table of the development of the foetus at the end of this section. 
Development of the Spine.-We have already traced the first steps in the 
formation of the spine: (1) The heaping up of two longitudinal ridges from the cells 
of the epiblast on either side of the primitive streak, so as to form a groove, and 
the gradual growing together of these ridges (laminae dorsales), so as to convert the 
. 1 The scope of this work only permits the briefest possible reference to these subjects. Those whc 
wish to study the subject of embryology in more detail are referred to Kblliker's Entwickelungs- 
geschichte, to the chapters on the development of the various organs in the ninth edition of Quain's 
Anatomy, or to the works of Prof. Dalton and of Foster and Balfour. 114 
GENERAL ANATOMY. 
groove into a canal, which is lined by epiblast, and out of which the spinal cord is 
developed. (2) The formation in front of this groove of a continuous cellular cord 
enclosed in a structureless sheath, the notochord or chorda dorsalis (Fig. 93). The 
notochord extends from the cephalic to the caudal extremity of the embryo, and lies 
in the place which is afterward occupied by the bodies of the vertebrae. It is prob- 
ably derived from the mesoblast, but possibly from the hypoblast (Balfour). (3) On 
either side of the notochord a portion of the mesoblastic layer is divided longitudi- 
nally from the rest of the mesoblast, so as to form a thick column, which extends 
from the cephalic to the caudal extremity of the embryo on either side of the spinal 
canal and notochord (Fig. 88, A 7); this is the protovertebral column. From the 
greater part of it is derived the vertebral column, a small portion at the upper and 
outer part being differentiated from it and eventually forming the muscles of the 
Fig. 93. 
Fig. 94. 
Cervical Part of the Primitive Vertebral 
Column and adjacent parts of an embryo 
of the sixth day, showing the division of 
the primitive vertebral segments (from 
Kolliker, after Remak): 1,1, chorda dor- 
salis in its sheath, pointed at its upper 
end; 2 points by three lines to the orig- 
inal intervals of the primitive vertebra:; 
3, in a similar manner, indicates the 
places of new division into permanent 
bodies of vertebree; c indicates the body 
of the first cervical vertebra: in this and 
the next the primitive division has dis- 
appeared, as also in the two lowest repre- 
sented-viz. d and the one above; in these 
intermediate the line of division is shown; 
4 points in three places to the vertebral 
arches; and 5, similarly, to three com- 
mencing ganglia of the spinal nerves : 
the dotted segments outside these parts 
are the muscular plates. 
Transverse Section through the Dorsal Region of an Embryo 
Chick, end of third day (from Foster and Balfour): Am, am- 
nion ; mp, muscle-plate; cv, cardinal vein; Ao, dorsal aorta at 
the point where its two roots begin to join; Ch, notochord; 
Wd, Wolffian duct; Wb, commencement of formation of Wolff- 
ian body; ep, epiblast; so, somatopleure; hy, hypoblast: the 
section passes through the place where the alimentary canal 
(hy) communicates with the yolk-sac. 
back. (4) This column undergoes a process of transverse segmentation and becomes 
converted into a number of quadrilateral blocks, the protovertebral somites (Fig. 94). 
The process of segmentation commences in the cervical region, and proceeds succes- 
sively through the other regions of the spine until a number of segments are formed, 
which correspond very closely to the number of the permanent vertebrae. (5) These 
protovertebral somites extend laterally; they grow forward and inward until they 
meet in front of the notochord in the middle line, which they thus enclose; and 
backward and inward around the spinal canal, which they also enclose. The noto- 
chord and the spinal canal are thus surrounded by a cellular mass derived from the 
mesoblastic layer, which constitutes the membranous matrix of the vertebrae. This 
structure is covered on its internal surface by hypoblast, and on its outer by epiblast, 
and presents the transverse segmentation already described (p. 106). (6) The next 
step is the conversion of this primitive membranous matrix into cartilage. This 
takes place probably about the fourth or fifth week in the human embryo (Kolliker). DEVELOPMENT OF THE CRANIUM AND FACE. 
115 
The part of the protovertebral somites which has extended backward to enclose the 
spinal foramen, and which eventually forms the arches of the vertebrae, simply 
undergoes a process of chondrification, so that the permanent arches correspond to 
the primary segments of the protovertebral somites, spaces being left between them 
for the spinal nerves and ganglia to grow out from the spinal cord. But a some- 
what more complex change goes on in the portion of the protovertebral somites which 
encloses the notochord, and which is destined to form the bodies of the vertebrae. 
Here each one of the protovertebral segments undergoes a second transverse division 
through its centre, and in the interval which is left between these secondary segmen- 
tations the fibrous structure of the intervertebral disks is formed. The half-segment 
of the original protovertebral somites on either side of this secondary segmentation 
joins with the segment above and below and undergoes chondrification, and thus 
forms the basis of the future body of a vertebra. Each cartilaginous body of a ver- 
tebra is formed therefore out of half an original protovertebral plate joined to the 
half of another plate above or below it, as the case may be. (7) The notochord 
contained in the centre of this chondrifying mass does not continue to grow, but 
becomes in the human subject relatively smaller, so as, at last, to form a mere slen- 
der thread, except opposite the secondary segmentations; that is to say, corre- 
sponding to the intervals between the bodies of the permanent vertebrae. Here 
it presents thickenings which are supposed by some to form the central pulp of the 
intervertebral disks. 
The further development of the vertebrae and the ossification of this cartilaginous 
structure are described in the body of the work. 
Development of the Cranium in G-eneral, and the Face.-We have seen 
that the first trace of the embryo consists in the formation of a longitudinal fold of 
the epiblast on either side of a median groove, and that these folds or ridges grow 
backward and meet in the median line, thus forming a canal. This canal, at the 
cephalic extremity of the embryo, is dilated and forms a bulbous enlargement. The 
bulbous enlargement soon expands into three vesicular dilatations, which are known 
as the three primary cerebral vesicles, from which all the different parts of the 
encephalon are presently to be developed. The most anterior of the three forms 
the optic thalamus, whilst a hollow projection from it forms the corpus striatum and 
the cerebral hemispheres; the middle one forms the tubercula quadrigemina; the 
posterior, the medulla oblongata. The primary cerebral vesicles are at this time, of 
course, hollow, and their cavities freely communicate 
with each other at the points of constriction. As the 
embryo grows the cerebral vesicles become twice bent 
forward on their own axis (Fig. 95, and Fig. 96, A and 
b). The upper oi' posterior curvature is called the cere- 
bral ; the lower or anterior, the frontal protuberance. 
Thus, we have a triple cavity (see Fig. 96, A, where 
the three cavities are marked c, me, and mo), lined by 
epiblast and covered by the same structure. Between 
these two layers of epiblast a layer of mesoblast, de- 
rived from the protovertebral plates of the trunk, is 
prolonged and spreads over the whole surface of the 
cerebral vesicles. From these structures the cranium 
and its contents are developed. The external layer of 
the epiblast forms the superficial epithelium of the scalp. 
The mesoblastic layer forms the true skin, the blood-ves- 
sels, muscles, connective tissue, bones of the skull, and 
membranes of the brain. The layer of epiblast lining 
the cavity forms the nervous substance of the encepha- 
lon, while the cavity itself constitutes the ventricles. 
The upper end of the notochord terminates at its cephalic end in a pointed 
extremity, which extends as far forward as the situation of the future body of the 
sphenoid bone, and is there imbedded in a mass of tissue, the " investing mass of 
Fig. 95. 
Longitudinal Section of the Head 
of an Embryo four weeks old, 
seen from the inside: 1, ocular 
vesicle; 2, optic nerve flattened 
out; 3, fore brain; 4, interme- 
diary brain; 5, middle brain; 6, 
hinder brain; 7, after brain; 8, 
anterior portion of the tentorium 
cerebelli; 9, its lateral portion in- 
tervening between Nos. 4 and 5; 
10, the pharyngeal curve, bent 
into a cul-de-sac; 11, the audi- 
tory vesicle. 116 
GENERAL ANATOMY. 
Rathke." This mass, derived from mesoblastic tissue, becomes cartilaginous, and 
from it is developed the basi-occipital and basi-sphenoid bones; and by lateral ex- 
pansions from it the occipi- 
tals, the greater wings of 
the sphenoid, and the peri- 
otic mass of cartilage sur- 
rounding the primary audi- 
tory vesicles. From the 
front of the investing mass 
of Rathke, which corre- 
sponds in position to the 
future dorsum sellse, two 
lateral bars are directed 
forward, enclosing a space 
which forms the pituitary 
fossa, in which the pitui- 
tary body is eventually de- 
veloped. These bars are 
named the trabeculae cranii, 
and extend as far forward 
as the anterior extremity 
of the head, where they 
coalesce with each other. 
From them the presphe- 
noid and lateral masses of 
the ethmoid are developed ; 
and from their coalescence 
a process is prolonged 
downward to form a por- 
tion of the framework of 
the face, hereafter to be 
described. From the pre- 
sphenoids, which are devel- 
oped from these trabeculae, 
a lateral expansion takes 
place, which forms the or- 
bito-sphenoid or lesser wings 
of the sphenoid, enclosing 
the optic foramen. 
The portions of the base 
of the skull above enumer- 
ated are formed from carti- 
lage ; the remaining parts, comprising the vault of the skull, are of membranous 
formation. 
The head at first consists simply of a cranial cavity, the face being subsequently 
developed, in the manner now to be described, by a series of arches with clefts 
between them (Fig. 97). It is usual in our textbooks to describe the arches as a 
series of processes which jut out and grow downward, inclining toward each other 
until they meet in the middle line and thus form a series of inverted arches, whilst 
the clefts are the spaces left between these pairs of processes. This, however, is 
scarcely the true description, and leads rather to the false impression that the arches 
are formed by processes budding out from the embryo, much in the same way as the 
extremities do, and, like them, are free on every side. What would appear rather to 
be the case is that the clefts are first formed, and that the arches consist of a thick- 
ening of the tissue on either side of the cleft. The arches thus formed may be 
divided into two sets, according as they are placed in front or behind the buccal 
cavity or mouth, the former being known as the prce-oral, and the latter as the post 
Fig. 96. 
Vertical Section of the Head in Early Embryos of the Rabbit (magnified 
from Milhalkovics): A, from an embryo of five millimeters long; B, 
from an embryo of six millimeters long; C, vertical section of the an- 
terior end of the notochord and pituitary body, etc., from an embryo 
sixteen millimeters long. In A the faucial opening is still closed; in B, 
it is formed: c, anterior cerebral vesicle; me, meso-cerebrum; mo, me- 
dulla oblongata; co, corneous layer; m, medullary layer; if, infun- 
dibulum ; am, amnion; spe, spheno-ethmoidal; be, central (dorsum sel- 
lae), and spo, spheno-occipital parts of the basis crahii; h, heart; f, ante- 
rior extremity of primitive alimentary canal and opening (later) of the 
fauces; i, cephalic portion of primitive intestine; tha, thalamus; p', 
closed opening or the involuted part of the pituitary body (py); ch, 
notochord; ph, pharynx. DEVELOPMENT OF FACE. 
117 
oral or visceral arches. Four clefts on each side appear laterally in the undifferen- 
tiated somato-splanchno-pleural wall of the fore-gut, and between them thickenings 
occur which ultimately meet and fuse in the 
middle line, and above are connected with the 
investing mass. These are the so-called post- 
oral visceral arches. Differentiation of tissue 
occurs from above downward, and cartilage is 
formed in them in connection with the invest- 
ing mass. The first post-oral arch has no cleft 
in front of it, but forms a rim in front of the 
fore-gut. The prse-oral arches are formed in 
much the same way by local thickening, in 
which differentiation of tissue and formation of 
cartilage proceed in a direction forward and 
downward from the investing mass. 
The prce-oral or maxillary arch unites with 
the fronto-nasal process. The latter consists 
of three plates, a central single one and two 
lateral ones. The central is called the "mid- 
frontal" process. It is prolonged downward 
and forward from the middle of the base of the 
skull, from the point of coalescence of the two 
trabeculae cranii, and from it the septum of the 
nose is developed. It is free in front and be- 
low, but behind it is united with the coalesced 
portion of the trabeculae, which therefore prob- 
ably assists in the formation of the septum nasi, 
and, in addition, of the prominent part of the 
future nose. The lateral plates of the fronto- 
nasal process are separated from the central one 
by a depression or furrow on either side; these furrows form the primary nasal pits 
or fossae. The lateral plates project downward parallel to the mid-process for a 
certain distance, and then, curving inward, unite with it, thus shutting off the nasal 
fossae from the rest of the face. The lateral masses of the ethmoid and lachrymal 
bones are developed in the lateral plates, and by their union with the mid-frontal 
process they form the intermaxillary bone and the lunula, or central part of the 
upper lip. 
The maxillary processes spring from the base of the skull farther back than the 
fronto-nasal, and at their origin are closely connected with the first post-oral or vis- 
ceral arch. They descend for a short distance, forming the outer wall of the orbit, 
in which the malar bone is developed; they then incline inward, and, meeting the 
lateral plate of the fronto-nasal process, form the floor of the orbit and shut it off 
from the rest of the face; then, continuing their course downward and inward, they 
join the mid-frontal process, and with it complete the alveolar arch and the superior 
maxillary bone. Finally, palatal processes are formed by an extension of the inner 
sides of this arch; these coalesce with each other in the median line, thus separat- 
ing the cavity of the mouth from the nasal fossse, and completing the palate. In 
front, however, the palatal processes do not join with the mid-frontal process, but 
a cleft is left which constitutes the naso-palatine canal. 
The post-oral arches are five in number in the Amniota, and of these the first 
only is concerned in the formation of the face proper, for the lower jaw or mandible 
is developed from it, and hence it is called the mandibular arch. The second forms 
the upper part of the hyoid bone, and is therefore named the hyoid arch. The third, 
in which the remainder of the hyoid bone is formed, and the remaining two, corre- 
spond to the arches which in aquatic animals form the gills, but which in the Amni- 
ota never do so. They are appropriately named branchial, a name which was pri- 
marily given to the whole series by Rathke, who first described them. 
Fig. 97. 
Face of an Embryo of twenty-five to twenty- 
eight days (magnified 15 times): 1, frontal 
prominence; 2, 3, right and left olfactory 
fossse; 4, inferior maxillary tubercles, united 
in the middle line; 5, superior maxillary tu- 
bercles; 6, mouth or fauces; 7, second pha- 
ryngeal arch ; 8, third ; 9, fourth ; 10, prim- 
itive ocular vesicle; 11, primitive auditory 
vesicle. 118 
GENERAL ANATOMY. 
The deeper part of the first or mandibular arch contains a transitory cartilaginous 
rod which has long been known as the "cartilage of Meckel," from the posterior end 
of which the malleus is formed, while its middle portion is converted into the inter- 
nal lateral ligament of the lower jaw, and its distal end enters into the formation of 
the symphysis and perhaps of the body of the bone. 
Between the mandibular arch and the prae-oral arch the buccal cavity or mouth 
is formed; this, therefore, is bounded by the prse-oral and post-oral arches, and its 
walls consist of mesoblastic tissue lined by epiblast. It is at first quite distinct from 
the upper part of the alimentary canal, which, as we shall hereafter see, is formed 
by the inner or splanchno-pleural layer of the mesoblast and the hypoblast, the two 
cavities being separated by all the layers of the blastodermic membrane. A com- 
munication between the two is, however, gradually effected by the fusion of the 
anterior end of the primitive alimentary cavity [with the hinder portion of the epi- 
blastic involution from which the mouth is formed]. 
The second post-oral arch {hyoid} is closely united with the first at its origin. It 
forms the incus, the stylo-hyoid ligament, and the lesser cornua of the hyoid bone. 
The third arch {thyro-hyoid} forms the greater cornua and body of the hyoid 
bone, and supports the rudiment of the thyroid cartilage and the rest of the larynx. 
The fourth and fifth arches enter merely into the formation of the soft parts of 
the neck, and do not give rise to any special organs. 
Between each of these visceral arches are clefts, four in number, which run 
through the tissues of the neck to the cavity of the pharynx: the first persists, 
though only in a portion of its extent, forming the Eustachian tube, the meatus 
auditorius, and the tympanic cavity. The other fissures are wholly closed by the 
sixth week.1 
Development of the Nervous Centres and the Nerves.-The medullary groove 
above described (p. 105) presents, about the third week, three dilatations at its upper 
end, separated by two constrictions, and at its posterior part another dilatation, called 
the rhomboidal sinus. Soon afterward the groove becomes a closed canal {medullary 
canal} and a soft blastema lines it, exhibiting corresponding dilatations. This is the 
rudiment of the cerebro-spinal axis. As the embryo grows, its cephalic part becomes 
more curved, and the three dilatations at the anterior end of the primitive cerebro- 
spinal axis become vesicles distinctly separated from each other (Fig. 95). These 
are the cerebral vesicles-anterior, middle, and posterior. The anterior cerebral 
vesicle (situated, at this period, quite below the middle vesicle) is the rudiment of 
the third ventricle and of the parts surrounding it-viz. the optic thalami and all 
the parts which form the floor of the third ventricle. The middle vesicle represents 
the aqueduct of Sylvius, with the corpora quadrigemina. The posterior vesicle is 
developed into the fourth ventricle, and its walls form the pons Varolii, medulla 
oblongata, and the parts in the floor of the fourth ventricle. 
At an early period in the development of this primitive brain a protrusion takes 
place from the anterior vesicle, which is at first simple, but soon becomes divided 
into two parts by an antero-posterior fissure. These expand laterally, and the 
1 The relations of these pharyngeal arches to the cranial nerves are of the greatest interest in a 
morphological point of view, but are hardly yet quite settled. Prof. Parker has lately described the 
ossification of the skull as proceeding from five arches-a prse-oral and four pharyngeal or post-oral, 
the post-oral being the mandibular or inferior maxillary; the hyoid; the thyro-hyoid; and the 
fourth, which, as above stated, has no remnant in the skeleton. The fifth cranial nerve, the facial, 
and the glosso-pharyngeal have definite relations to these arches, each dividing so that its anterior 
and posterior divisions embrace the cleft, or are distributed on the " bars," as Professor Parker calls 
them, which bound the cleft. Thus the front division of the trigeminus is distributed in front of the 
buccal cleft on the prae-oral arch, and its posterior division on the first pharyngeal or mandibular; 
the facial sends its anterior division-represented in the mature condition by the chorda tympani- 
in front of the Eustachian fissure (the remains of the first cleft) to the mandibular arch, while its 
descending branches go to the hyoid arch; the glosso-pharyngeal sends its lingual portion to the 
hyoid arch, while its pharyngeal part is distributed to the thyro-hyoid. 
These relations are exceedingly suggestive, and the method of inquiry most fruitful in promise 
for the higher anatomy, which aims at uniting into one plan all the various forms of ova and the 
animals developed from them; but as yet these relations are hardly sufficiently established in fact 
to be made a necessary part of scholastic teaching. DEVELOPMENT OF NERVOUS CENTRES. 
119 
cerebral hemispheres and corpora striata are developed from them. From the fore 
part of the posterior cerebral vesicle a similar protrusion takes place, forming the 
rudiment of the cerebellum. In consequence of these protrusions or outgrowths 
taking place, the three primary cerebral vesicles are now converted into six per- 
manent rudiments of the brain and medulla oblongata. The anterior part of the 
original anterior cerebral vesicle (fore-brain, Prosencephalon), now divided into two, 
constitutes the cerebral hemispheres, corpus callosum, corpora striata, fornix, lateral 
ventricles, and olfactory bulbs. These parts lie at first quite covered and concealed 
by those formed from the middle primary vesicle and by the optic thalami, which, 
with the optic nerves, the third ventricle, and the parts in its floor, are furnished by 
the posterior portion of the anterior vesicle (inter-brain, Thalamencephalon). By 
the third month, however, the hemispheres have risen above the optic thalami, and 
by the sixth month above the cerebellum. Fissures are seen on the surface of the 
hemispheres at the third month, but all except one disappear. This one persists, 
and forms the fissure of Sylvius. The permanent fissures for the convolutions do 
not form till about the seventh or eighth month. The middle cerebral vesicle (mid- 
brain, Mesencephalon) is at first situated at the summit 
of the angle shown on Fig. 95. Its smooth surface is 
soon divided by a median and transverse groove into four 
tubercles (tubercula quadrigemina), which are gradually 
covered in by the growth of the cerebral hemispheres. 
Its cavity diminishes as its walls thicken, and contracts 
to form the aqueduct of Sylvius. The crura cerebri are 
also formed from this vesicle. The third primary cerebral 
vesicle at an early period (between the ninth and twelfth 
week) consists of the hind-brain, or Epencephalon, form- 
ing the cerebellum, pons Varolii, and anterior part of the 
fourth ventricle; and of the after-brain, or Metencephalon, 
which forms the medulla oblongata with the rest of the 
fourth ventricle. 
The development of the pituitary body has of late 
received much attention, and important questions of 
morphology are connected with it. The description 
which is now accepted regards the pituitary body as the 
place of meeting of the epiblast, hypoblast, and meso- 
blast at the extremity of the notochord; it contains rudi- 
ments from each of these sources, or at least from the 
epiblast and hypoblast, for the mesoblastic elements 
derived from the chorda dorsalis are now said early to 
become displaced and to disappear. At the point where the notochord terminates 
anteriorly the medullary layer of the epiblast, or that from which the central ner- 
vous system is developed, is reflected downward to form a little pouch (Fig. 96, c, 
af)-the infundibulum. At the same time the hypoblast passes upward from the 
pharynx, or upper end of the primitive intestine, to form, along with the common 
layer of the epiblast, a similar pouch, which becomes closed and converted into a 
glandular body, the anterior part of the pituitary body or hypophysis (Fig. 96, C,py}- 
The end of the notochord lies at first between the infundibulum and the hypophysis; 
but it is believed that, as the hypophysis becomes closed off and separated from the 
pharynx, the two parts of the pituitary body are carried backward and upward from 
off the end of the notochord, so as to leave the latter stranded, as it were, below the 
pituitary fossa. Others refer the hypophysal part of the pituitary body to epiblastic 
elements derived from the buccal part of the epiblast only, and so connect its devel- 
opment, not with the pharynx, but with the mouth and the anterior portion of the 
skull. The question is an obscure one, but its main interest is to remind the reader 
that this peculiar appendage to the brain forms, in an early condition of the foetus, 
the meeting-point of the portions of the ovum from which the nervous centres, the 
alimentary canal, the mouth, and the base of the skull are developed; and that its 
Fig. 98. 
Section of the Medulla in the 
Cervical Region, at six weeks 
(magnified 50 diameters): 1, 
central canal; 2, its epithe- 
lium ; 3, anterior gray matter; 
4, posterior gray matter; 5, an- 
terior commissure; 6, posterior 
portion of the canal, closed by 
the epithelium only; 7, an- 
terior column: 8, lateral col- 
umn ; 9, posterior column; 10, 
anterior roots; 11, posterior 
roots. 120 
GENERAL ANATOMY. 
development has some connection, as yet imperfectly understood, with that of these 
or some of these great sections of the body.1 
When the medullary groove is first closed the foetal spinal marrow occupies the 
whole of it, and presents a large central canal, which gradually contracts in con- 
sequence of the thickening and rapid growth of the epiblast around it. This 
increase in thickness takes place principally at the sides, so that eventually the 
central canal acquires on section the appearance of a slit. Eventually, the two 
sides join in the middle, and the original canal is divided into two-an anterior, 
which becomes the central permanent canal, which in after-life is no longer per- 
ceptible to the eye, though it is still visible on microscopic section; and a posterior, 
which becomes filled about the ninth week with a septum of connective tissue from 
the pia mater, and forms the posterior fissure of the cord. 
About the fourth month the spinal column begins to grow in length more rapidly 
than the medulla spinalis, so that the latter no longer occupies the whole canal. 
The cord is composed at first entirely of uniform-looking cells, which soon separate 
into two layers, the inner of which forms the epithelium of the central canal, while 
the outer forms the central gray substance of the cord. The white columns are 
formed latei*; their rudiments can be detected about the fourth week, and some 
embryologists believe that they are developed from the mesoblast. 
The cerebral and spinal membranes are, according to Kolliker, a production from 
the protovertebral disks, and are recognizable about the sixth week. As the fissures 
separating the segments of the cerebro-spinal axis appear, the membranes extend 
through them and the pia mater passes into the cerebral ventricles. Bischoff, 
however, describes the pia mater and arachnoid as developed from the cerebral 
vesicles, so that they are, according to him, formed in the position which they per- 
manently occupy. 
The Nerves.-The nerves are developed as secondary growths in the mesoblast. 
The spinal nerves are developed as follows: Along either side of the rudimentary 
spinal cord, close to the point of involution of the epiblast in the median line, a 
series of cellular swellings, constituting the neural crest, appear, corresponding in 
number to the number of the spinal nerves. They are the rudiments of the 
posterior roots of the spinal nerves. In some animals the swellings are con- 
nected with each other by longitudinal fibres. They at first consist entirely of 
cells, and, growing, become differentiated into a narrow part or root, a thickened 
portion, the ganglion, and beyond this a second narrowed portion, which joins the 
anterior root to form the nerve itself. The root gradually changes its place, and, 
instead of arising from the spinal cord close to the median line, gradually shifts its 
position toward the lateral wall more anteriorly. The anterior roots are also out- 
growths from the spinal cord. They appear later than the posterior roots, and arise 
from the lateral wall in the first instance, and therefore do not shift their position. 
The two roots gradually converge and unite, and from the point of union the nerve 
grows toward its peripheral termination. The cellular structure of which it is com- 
posed disappears, and fibres first make their appearance in the anterior roots. Most 
of the cranial nerves are developed in the same manner as the posterior roots of the 
spinal nerves. The first, third, fifth, the facial, the auditory, the glosso-pharyngeal, 
and the pneumogastric arise from a series of dorso-lateral swellings on the cephalic 
portion of the embryonic cerebro-spinal nervous system. As in the spinal nerves, 
the swelling, which shows some traces of differentiation into root, ganglion, and 
peripheral portion, gradually changes its point of origin, so as eventually to become 
attached at a much lower level. With regard to the mode of origin of the fourth, 
sixth, spinal accessory, and hypoglossal we possess no exact knowledge. It must be 
1 [I would prefer to state this as follows: The epiblast of the back part of the roof of the oral 
invagination, where a hollow, saccular portion of the oral epiblast is constricted off and fuses with 
the median infundibular process of the floor of the brain (Fig. 96, c, if), is developed into the 
pituitary body or hypophysis. The fusion of the infundibulum with the involution from the epiblast 
of the upper and posterior part of the oral cavity leads to the formation of the pituitary body or 
hypophysis. This, therefore, is entirely of epiblastic origin, and its relations indicate that at one 
time the oral cavity and the brain may have been more intimately connected than at present.] DEVELOPMENT OF THE EYE. 
121 
mentioned, however, that Marshall believes that the abducens and the hypoglossal 
arise as anterior or motor roots to two of the other cranial nerves, though they do 
not join with them, as in the spinal nerves, to form a compound nerve. 
The optic nerve arises in a manner entirely different from any of the other era- 
nial nerves. 
The sympathetic nerves are developed in connection with the gangliated roots of 
the spinal and cranial nerves. 
Development of the Eye.-The nervous elements and non-vascular parts of 
the eye are formed from the epiblast, and the vascular portions from the mesoblast; 
but the method of development is somewhat complicated. The essential portion of 
the eye-i. e. the retina and the parts immediately connected with it-is an out- 
growth from the rudimentary brain (primitive ocular vesicle); and this outgrowth 
is met by an ingrowth from the common epidermic or corneous layer of the epiblast, 
out of which the lens and the conjunctival and corneal epithelium are developed. 
The first appearance of the eye consists in the protrusion or evolution from the 
medullary wall of the thalamencephalon or inter-brain of a vesicle called the prim- 
itive ocular vesicle. This is at first an open cavity communicating by a hollow stalk 
with the general cavity of the cerebral vesicle. As development advances the hollow 
stalk becomes solid and thus the optic nerve is formed, receiving, however, in a way to 
be presently explained, mesoblastic elements for the formation of its central artery and 
connective tissue. As the primitive ocular vesicle is prolonged forward, it meets the 
epidermic layer of the epiblast, which at the point of contact becomes thickened, 
and then forms a depression which gradually encroaches on the most prominent part 
of the primitive ocular vesicle, which in its turn appears to recede before it, so as to 
become at first depressed and then inverted in the manner indicated by the annexed 
figure (Fig. 99, a), so that the cavity is finally almost obliterated by the folding back 
of its anterior half, and the original sac converted into a cup-shaped cavity-the 
ocular cup-in which the involuted epiblastic layer, the rudiment of the lens, is 
received (Fig. 99, b). This cup-shaped cavity consists therefore of two layers: one, 
the outer, originally the posterior half of the primitive ocular vesicle, is thin, and 
eventually forms the pigmental layer of the retina;1 the other layer, the inner, 
originally the anterior or more prominent half, which has become folded back and 
is much thicker, is converted into the nervous layers of the retina. Between the 
two are the remains of the cavity of the original primary vesicle, which finally 
becomes obliterated by the union of its two layers. As development proceeds the 
cup-shaped cavity or ocular cup increases in size, and thus a space is formed between 
it and the rudimentary lens which it contains; this is the secondary ocular vesicle, 
and in it the vitreous humor is developed (Fig. 99, c). The folding in of the pri- 
mary optic vesicle to produce the optic cup proceeds from above downward, and grad- 
ually surrounds the lens, but leaves an aperture or fissure below-the choroidal fis- 
sure or ocular cleft-through which vascular elements, within the vesicle and derived 
from the mesoblast, retain their connection with the rest of the mesoblast. The lens 
is at first a thickening of the epiblast; then a depression or involution takes place, 
thus forming an open follicle, the margins of which gradually approach each other 
and coalesce, forming an enclosed cavity of epiblastic cells (Fig. 99). At the point 
of involution the external layer of epiblast separates from the ball of the lens and 
passes freely over the surface, so that the lens becomes disconnected from the epi- 
blastic layer from which it was developed, and recedes into the ocular cup, while the 
cuticular layer covering it is developed into the corneal epithelium. The cells form- 
ing the posterior or inner wall of the cavity, which is to form the lens, rapidly 
increase in size, becoming elongated and developed into fibres, and, filling up the 
cavity, convert it into a solid body. The cells on the anterior wall undergo no 
change and retain their cellular character. The secondary ocular vesicle, or space 
between the lens and the hollow of the ocular cup (Fig. 99, 0, 7, and Fig. 100) contains 
a quantity of mesoblastic tissue continuous through the ocular cleft with the rest of 
1 This layer forms functionally part of the choroid, and was formerly described as belonging to 
this membrane; it is now described as part of the retina, on account of its method of development. 122 
GENERAL ANATOMY. 
the mesoblast, and into this blood-vessels project themselves through the ocular cleft. 
The iris and ciliary processes are formed from this vascular tissue, and the choroid 
is developed in the mesoblast surrounding the ocular vesicle; and at the same time 
a process of the mesoblast is believed to extend down the stalk of the primitive 
ocular vesicle to form the arteria centralis retinae with the sheath and connective 
tissue of the optic nerve. A portion of this tissue also becomes converted into the 
vitreous humor, and surrounds the lens with 
a vascular membrane-the vascular capsule 
of the lens-which is connected with the ter- 
mination of the temporary artery (hyaloid) 
that forms the continuation of the central 
artery of the retina through the vitreous 
Fig. 100. 
Fig. 99 
Diagrammatic Sketch of a Vertical Longitudinal 
Section through the Eyeball of a Human Foetus 
of four weeks (after Kblliker-magnified 100 
diameters). The section is a little to the side, so 
as to avoid passing through the ocular cleft: c, 
the cuticle, where it becomes later the cornea; 
I, the lens ; op, optic nerve formed by the pedicle 
of the primary optic vesicle ; vp, primary medul- 
lary cavity of the optic vesicle; p, the pigment- 
layer of the outer wall; J, the inner wall form- 
ing the retina; vs, secondary optic vesicle con- 
taining the rudiment of the vitreous humor. 
Diagram of Development of the Lens: A, B, C, different 
stages of development: 1, epidermic layer; 2, thickening 
of this layer; 3, crystalline depression; 4, primitive ocu- 
lar vesicle, its anterior part pushed back by the crystal- 
line depression; 5, posterior part of the primitive ocular 
vesicle, forming the external layer of the secondary ocu- 
lar vesicle; 6, point of separation between the lens and 
the epidermic layer; 7, cavity of the secondary ocular 
vesicle, occupied by the vitreous. 
chamber. This vascular capsule of the crystalline lens forms the membrana pupil- 
laris (described on a subsequent page), and also attaches the borders of the iris to 
the capsule of the lens. It disappears about the seventh month. 
The eyelids are formed at the end of the third month as small cutaneous folds, 
which come together in front of the globe and cornea. This union is broken up and 
the eyelids separate before the end of foetal life. 
The lachrymal canal appears to result from the non-closure of a fissure which 
exists between the lateral plates of the fronto-nasal and maxillary processes (p. 117). 
Development of the Ear.-The first rudiment of the ear appears shortly after 
that of the eye, in the form of a thickening of the epiblast on the outside of that 
part of the third primary cerebral vesicle which eventually forms the medulla oblon- 
gata, opposite the dorsal end of the second pharyngeal arch. The thickening is 
then followed by an involution of the epiblast, which becomes deeper and deeper, 
sinking toward the base of the skull, and a flask-shaped cavity is formed; by the 
narrowing of the external aperture the neck of the flask constitutes the recessus 
labyrinthi. The mouth of the flask then becomes closed, and thus a shut sac is 
formed, the primitive auditory or otic vesicle, which by its sinking inward comes to 
be placed between the alisphenoid and basi-occipital .matrices. From it the internal 
ear is formed. The middle ear and the Eustachian tube are developed from the 
remains of the first branchial cleft, while the pinna and external meatus are devel- 
oped from outgrowths surrounding the posterior margin of the same cleft. The 
primary otic vesicle becomes imbedded in a mass of mesoblastic tissue, which rapidly 
undergoes chondrification and ossification. It, as before stated, is at first flask- or 
pear-shaped; the neck of the flask, or recessus labyrinthi, prolonged backward, 
forms the aquaeductus vestibuli. From it are given off certain prolongations or 
diverticula from which the various parts of the labyrinth are formed. One from 
the anterior end gradually elongates, and, forming a tube, bends on itself from left 
to right and becomes the cochlea. Three others, which appear on the surface of the 
vesicle, form the semicircular canals. Of these, the one which is to constitute the DEVELOPMENT OF THE SKIN. 
123 
external semicircular canal does not appear at such an early date as the other two. 
Subsequently, a constriction takes place in the original vesicle, which, gradually 
increasing, divides it into two, and from these are formed the utricle and saccule. 
Finally, the auditory nerve, which has been developed from the "neural crest" in 
the manner above described (p. 120), pierces the auditory capsule in two main divis- 
ions-one for the vestibule, the other for the cochlea. The middle ear and Eusta- 
chian tube are the remains of the first pharyngeal or branchial cleft (hyo-mandib- 
ular), and are, from an early period, closed by the formation of the membrana 
tympani, which consists of a layer of epiblast externally, a layer of hypoblast 
internally, and, between the two, of mesoblastic tissue constituting its fibrous and 
vascular layer. Projecting into the cleft are the ossicles of the middle ear, the 
malleus being developed from the proximal end of the mandibular (Meckel's) carti- 
lage, the incus from the proximal end of the hyoidean cartilage, and the stapes as a 
deposit of cartilaginous cells around the fenestra ovalis. 
The external auditory meatus is developed, liked the pinna, from the soft parts 
on the posterior margin of the first visceral cleft by an outgrowth of the tissues in 
this situation. 
Development of the Nose.-The olfactory fossse, like the primary auditory 
vesicles, are formed in the first instance by a thickening and involution of the epi- 
blast which take place at a point below and in front of the ocular vesicle (Fig. 97, 
2, 3). The thickening appears at a very early period, about the fourth week. The 
borders of the involuted portion very soon become prominent in consequence of the 
development of the mid-frontal and lateral naso-frontal plates above spoken of (p. 
117), which are formed on either side of the rudimentary fossae. As these processes 
increase, the fossae deepen and become converted into a deep channel, which event- 
ually forms the upper part of the nasal fossae-that is, the two superior meatuses, 
the part to which the olfactory nerves are distributed. At this time they are con- 
tinuous with the buccal cavity, a portion of which forms the lower part or inferior 
meatus of the nasal fossae. For, as the palatine septum is formed, the buccal cavity 
is divided into two parts, the upper of which forms the lower part of the nasal fossae, 
while the remainder forms the permanent mouth. 
The soft parts of the nose are formed from the coverings of the frontal projec- 
tions and of the olfactory fossae. The nose is perceptible about the end of the 
second month. The nostrils are at first closed by epithelium, but this disappears 
about the fifth month. 
The olfactory nerve, as above pointed out, is formed from the anterior cerebral 
vesicle as a secondary vesicle on its under surface, and it lies upon the involuted 
epiblast, which subsequently forms the nasal fossae. 
Development of the Skin, G-lands, and Soft Parts.-The epidermis is pro- 
duced from the external, the true skin from the middle, blastodermic layer (Fig. 85, 
19, 20). About the fifth week the epidermis presents two layers, the deeper one 
corresponding to the rete mucosum. The subcutaneous fat forms about the fourth 
month, and the papillae of the true skin about the sixth. A considerable desqua- 
mation of epidermis takes place during foetal life, and this desquamated epidermis, 
mixed with a sebaceous secretion, constitutes the vernix caseosa with which the skin 
is smeared during the last three months of foetal life. The nails are formed at 
the third month, and begin to project from the epidermis about the sixth. The 
hairs appear between the third and fourth months in the form of depressions of the 
deeper layer of the epithelium, which then become inverted by a projection from the 
papillary layer of the skin. The papillae grow into the interior of the epithelial 
layer; and finally, about the fifth month, the foetal hairs (lanugo) appear first on 
the head and then on the other parts. These hairs drop off after birth and give 
place to the permanent hairs. The cellular structure of the sudoriferous and seba- 
ceous glands is formed from the epithelial layer, while the connective tissue and 
blood-vessels are derived from the mesoblast about the fifth or sixth month. The 
mammary gland is also formed partly from mesoblast-its blood-vessels and con- 
nective tissue ; and partly from epiblast-its cellular elements. Its first rudiment is 124 
GENERAL ANATOMY. 
seen about the third month, in the form of a small projection inward of epithelial 
elements, which invade the mesoblast; from this similar tracts of cellular elements 
radiate; these subsequently give rise to the glandular follicles and ducts. The 
development of the former, however, remains imperfect, except in the adult female, 
and especially after pregnancy. 
Development of the Limbs.-The upper and lower limbs begin to project, as 
buds, from the anterior and posterior part of the embryo about the fourth week. 
These buds are formed as short lateral, longitudinal folds of epiblast, into which 
mesoblast proliferates, opposite or just external to the point where the mesoblast 
splits into its parietal and visceral layers, and external to the vertebral somites, of 
which they may be regarded as lateral extensions. The division of the terminal 
portion of the bud into fingers and toes is early indicated, and soon a notch or con- 
striction marks the future separation of the hand or foot from the forearm. Next, 
a similar groove appears at the site of the elbow or knee. The indifferent tissue or 
blastema, of which the whole projection is at first composed, is differentiated into 
muscle and cartilage before the appearance of any internal cleft for the joints 
between the chief bones. 
The muscles become visible about the seventh or eighth Aveek. The source of 
their development is the mesoblast. The vertebral muscles are developed from the 
muscle-plates or protovertebral somites of the embryo (p. 106; see Fig. 85, C, 13), 
and the muscles of the neck and jaws, as well as those which enclose the cavities 
of the thorax and abdomen, are also formed from the same source. They do not 
meet in the middle line of the body till about the fourth month. The cutaneous 
muscles are developed from the cutaneous portion of the middle blastodermic layer. 
Development of the Blood-vascular System.-There are three distinct 
stages in the development of the circulatory system before it arrives at its com- 
plete or adult condition, in accordance with the manner in which nourishment is 
provided for at different periods of its existence. In the first stage there is the 
vitelline circulation, during which nutriment is extracted from the yolk or contents 
of the vitelline membrane. In the second stage there is the placental circulation, 
which commences after the formation of the placenta, and during which.nutrition is 
obtained by means of this organ from the blood of the mother. In the third stage 
there is the complete circulation of the adult, commencing at birth, and during 
which nutrition is provided for by the organs of the individual itself. 
1. The vitelline circulation is carried on partly within the body of the embryo, 
and partly external to it in the vascular area of the umbilical vesicle. It consists 
of a median tubular heart, from which two vessels (arteries) project anteriorly. 
These carry the blood to a plexus of capillaries spread over the area vasculosa, and 
also, though to a less extent, in the body of the embryo. From this plexus the 
blood is returned by two vessels (veins) which enter the heart posteriorly, and thus 
a complete circulation is formed. 
In these vessels and the heart a fluid (blood} is contained, in which rudimentary 
corpuscles are found. The mode of formation of these elementary parts will have 
first to be considered. 
In Mammalia the heart is formed by a hollowing out or vacuolation of a longi- 
tudinal group of mesoblastic cells on either side of the median line in front of the 
anterior extremity of the rudimentary pharynx, at about the level of the posterior 
primary cerebral vesicle. This vacuolation takes place in the visceral layer of the 
mesoblast, and round the cavity thus formed the layer becomes folded or redupli- 
cated, and presents two distinct strata of cells: the inner and thinner layer forms 
the endocardium, the outer and thicker the muscular Avail of the heart. In its very 
earliest and primitive condition the heart consists, therefore, of a pair of tubes, one 
on either side of the body. These, however, soon coalesce in the median line, and, 
fusing together, form a single central tube.1 Each of the two primary tubes receives 
posteriorly a large vessel (a vein), and is prolonged anteriorly into a second vessel 
(an artery). So that after fusion of the heart-tubes has taken place there is, in the 
1 In most fishes and in amphibia the heart originates as a single median tube. DEVELOPMENT OF THE HEART. 
125 
primitive vitelline circulation, as above mentioned, a single tubular heart, with two 
arteries proceeding from it and two veins emptying themselves into it. The earliest 
vessels are also formed in the visceral layer of the mesoblast. The indifferent cells 
of which this layer is composed become 
"vacuolated;" i. e. they become enlarged, 
and spaces are formed within them. The 
nuclei of these enlarged cells multiply; 
some few of the proliferated nuclei remain 
imbedded in the walls of the cell, but the 
greater number of them are free and are 
converted into blood-corpuscles. The vacuo- 
lated cells fuse together, forming cavities, 
and also give off processes which unite with 
processes of other cells : these in their turn 
become also vacuolated, and, communicating 
with the cavities in the original cells, a net- 
work of tubes is produced (Fig. 101). The 
tubes or primary vessels consist in the first 
instance of the original protoplasm of the 
cell, with here and there nuclei derived 
from the original divided nucleus imbedded 
in it. Then differentiation of the proto- 
plasm into flattened cells around these 
nuclei takes place, and constitutes the wall 
of the capillary or the lining membrane of 
the larger vessel. In these latter other 
cells, derived from the mesoblast, apply themselves externally and form the other 
coats of the vessel at a later period. 
The blood-disks are formed from the original divided nucleus of the vacuolated 
mesoblastic cells. They are free, and accumulate, each one around itself, a small 
quantity of the protoplasm of the cell, which rapidly acquires a tinge of color. The 
earliest blood-corpuscles are therefore at first nucleated, and in this and other respects 
resemble the white corpuscles. As soon, however, as the liver is formed, true white 
corpuscles make their appearance; and it seems that the chief source from which 
they are derived is the embryonic liver, though later on the spleen and lymphatic 
glands take up this function and continue it after birth. The nucleated condition 
of the red globules ceases before birth. The precise mode in which the nucleated 
white corpuscle is converted into the non-nucleated red blood-globule, whether by 
a change in the whole cell or by the disappearance of the cell and persistence of its 
nucleus, is not yet ascertained. The vitelline cir- 
culation commences about the fifteenth day and 
lasts till the fifth week. When fully established 
it is carried on as follows: Proceeding from the 
tubular heart are two arteries, the first aortic 
arteries (Fig. 102), which unite at some distance 
from the heart into a single artery. This runs 
down in front of the primitive vertebrae and in the 
walls of the intestinal cavity, and again divides 
into two primitive aortce or vertebral arteries, and 
these give off five or six omplialo-mesenteric arteries, 
which ramify in the germinal area, forming with 
their parent trunks a close network, terminating 
in veins which radiate toward an annular venous 
trunk-the terminal sinus. This vessel surrounds 
the vascular portion of the germinal area, but does 
not extend up to the anterior end of the embryo. 
It terminates on either side in a vein called the 
Fig. 101. 
Various Forms of Mother-cells undergoing Devel- 
opment into Blood-vessels, from the middle layer 
of the chick's blastoderm (Klein): a, large mother- 
cell vacuolated, forming the rudimentary vessel; 
b, the wall of this cell formed of protoplasm, 
with nuclei imbedded, and in some cases more 
or less detached and projecting; c, processes con- 
nected with neighboring cells, formed of the 
common cellular substance of the germinal area; 
d, blood-corpuscles; f, small mother-cells, vacuo- 
lation commencing; B, mother-cell, in which only 
obscure granular matter is found. 
Fig. 102. 
Heart at the Fifth Week: A, opened from 
the abdominal aspect; 1, arterial sinus; 
2, aortic arches uniting behind to form 
the descending aorta; 3, auricle ; 4, auric- 
ulo-ventricular orifice; 5, commencing 
septum ventriculorum ; 6, ventricle; 7, 
inferior vena cava. 
I;, Posterior View of the same : 1, trachea; 
2, lungs; 3, ventricles; 4,5, auricles; 6, 
diaphragm; 7, descending aorta; 8, 9, 
10, pneumogastric nerves and their 
branches. 126 
GENERAL ANATOMY. 
omphalo-mesenteric. The two omphalo-mesenteric veins open into the opposite 
extremity of the heart to that from which the arteries proceeded. This primitive 
circulation extends gradually from the germinal area over the whole of the umbilical 
vesicle, and the vessels external to the embryo disappear as the umbilical vesicle 
becomes atrophied. 
2. The Placental Circulation.-As the umbilical vesicle diminishes, the allantois, 
which is formed by a protrusion from the lower part of the intestine, enlarges and 
becomes converted into a vascular chorion, a part of which forms the placenta. 
When the umbilical vesicle disappears, this becomes the only source of nutrition for 
the embryo. The allantois carries with it two arteries, derived from branches of the 
primitive aorta, and two veins; these vessels become much enlarged as the placental 
circulation is established, but subsequently one of the veins disappears, and in the 
later stages of uterine life the circulation is carried on between the foetus and the 
placenta by two arteries and one vein (umbilical). 
During the occurrence of these changes great alterations take place in the prim- 
itive heart and blood-vessels, above alluded to, which will now require description. 
Further Development of the Heart.-The simple median tube formed by the 
coalescence of the pair of tubes of which the primitive heart consists becomes elon- 
gated and bent on itself, so as to form a U-shaped tube, the middle portion being 
protruded forward and to the right side, and at the same time twisted on itself, so 
that the extremity from which the arteries are prolonged is situated in front and to 
the right, and that into which the veins enter behind and to the left. The bent 
tube then becomes divided by two transverse constrictions into three parts. One, 
the posterior, becomes the auricles, the middle one forms the two ventricular cavities, 
while the anterior forms the aortic bulb, from which the commencement of the aorta 
and pulmonary artery is developed. A division of each of these cavities now takes 
place, so as to convert them into right and left ventricle, right and left auricle, and 
aorta and pulmonary artery respectively. This division first takes place in the 
middle portion of the tubular heart, the rudimentary ventricular cavities (Fig. 102, 
A, 5). A partition rises up from the lower part of the right wall of this cavity, and 
gradually grows up until it reaches the constrictions which separate it from the 
other two, and thus the interventricular septum is completed. At the same time a 
cleft appears on the outside, a little to the right of the most prominent point, which 
ultimately becomes the apex of the heart. This cleft becomes less marked as devel- 
opment progresses, but remains, to some extent, persistent throughout life as the 
interventricular groove. 
The first appearance of a division in the posterior or auricular portion of the 
tubular heart makes its appearance at a very early period of development in the 
shape of two projecting pouches, one on either side; these are the rudiments of the 
auricular appendages, but the actual division of the cavity by a septum does not 
occur until some time after the appearance of the ventricular septum. This is formed 
by the growth of a partition from the anterior wall of the auricular cavity, which 
grows backward, and partially separates the cavity into two. The partition, how- 
ever, is not completed until after birth, a part remaining undeveloped, and thus per- 
mitting of a communication (foramen ovale) between the two auricles during the 
whole of foetal life. In like manner, the aortic bulb is divided into two by the 
growth of a septum downward from the distal end of the bulb, dividing this cavity 
into two, the permanent aorta and pulmonary artery. Very soon a superficial fur- 
row appears on the external surface of this portion of the heart, corresponding to the 
septum internally, and, becoming deeper, the two vessels are gradually separated 
from each other through the septum, in the immediate neighborhood of the ventricu- 
lar portion of the heart, whilst beyond this they still remain joined together, and 
give origin to the fourth and fifth aortic arches, presently to be described. 
Further Development of the Arteries.-In the vitelline circulation two arteries 
were described as coming off from the primitive heart and running down in front of 
the developing vertebrae. The first change consists in the fusion of these arteries 
into one at some distance from the heart, thus forming the descending thoracic and DEVELOPMENT OF THE ARTERIES. 
127 
abdominal aorta. In consequence of the heart falling backward to the lower part 
of the neck, and then into the thorax, as the head is developed, the two original 
arteries, proceeding from the heart to the point of fusion in the common descending 
aorta, become elongated and assume an arched form, curving backward on each side 
from the front of the body toward the vertebral column (Fig. 103, a). These are 
Fig. 103. 
Diagram of the Formation of the Aortic Arches and the Large Arteries : I, n, in, iv, v, first, second, third, fourth, 
and fifth aortic arches; A, common trunk from which the first pair spring; the place where the succeeding 
pairs are formed is indicated by dotted lines; B, common trunk, with four arches and a trace of the fifth; 
C, common trunk, with the three last pairs, the first two having been obliterated; D, the persistent arteries, 
those which have disappeared being indicated by dotted lines; 1, common arterial trunk; 2, thoracic aorta; 
3, right branch of the common trunk, which is only temporary; 4, left branch, permanent; 5, axillary artery; 
6, vertebral; 7, 8, subclavian; 9, common carotid; 10, external, and 11, internal carotid; 12, aorta; 13, pul- 
monary artery; 14,15, right and left pulmonary arteries. 
the first or primitive aortic arches. As the heart recedes into the thorax, and these 
arches, which correspond in position to the first pharyngeal or mandibular arch, 
become elongated, four pairs of arches are formed behind them around the pharynx 
(Fig. 103). The arches, five in number, remain permanent in fishes, giving off from 
their convex borders the branchial arteries to supply the gills. In Mammalia the 
five pairs do not exist together, for the first two have disappeared before the others 
are formed. Only some of the arches in this class of animals remain as permanent 
structures ; other arches, or portions of them, become obliterated or disappear. The 
first two arches entirely disappear. The third remains as a part of the internal 
carotid artery, the remainder being formed by the upper part of the posterior aortic 
root-z. e. the descending part of the original vessel which proceeded from the rudi- 
mentary tubular heart. The common and external carotid are formed from the ante- 
rior aortic root; that is, the ascending portion of the same primitive vessel. The 
fourth arch on the left side becomes developed into the permanent arch of the aorta 
in mammals, but in birds it is the fourth arch on the right side which forms the aortic 
arch, while in reptiles the fourth arch on both sides persists, as there is a permanent 
double aortic arch. The fourth arch on the right side forms the subclavian artery, 
and by the junction of its commencement with the anterior aortic root, from which 
the common carotid is developed, it forms the innominate artery.1 The fifth arch on 
the left side forms the pulmonary artery and the ductus arteriosus ; that on the right 
side becomes atrophied and disappears. The first part of the fifth left arch remains 
connected with that part of the bulbus aortce which is separated as the pulmonary 
stem, and with it forms the common pulmonary artery. From about the middle of 
this arch two branches are given off, which form the right and left pulmonary arteries 
respectively, and the remaining portion-i. e. the part beyond the origin of the 
branches communicating with the left fourth arch ; that is, the descending part of 
the arch of the aorta-constitutes the ductus arteriosus. This duct remains pervious 
during the whole of foetal life, and after birth becomes obliterated. 
The development of the arteries in the lower part of the body is going on during 
the same time. We have seen that originally there were two primitive arteries com- 
ing off from the primary tubular heart, and that these two vessels at some distance 
from the heart became fused together to form a single median artery, which coursed 
down in front of the vertebrae to the bottom of the spinal column, forming the per- 
1 This is interesting in connection with the position of the recurrent laryngeal nerve, which is 
thus seen to hook round the same primitive fcetal structure, which becomes on the right side the sub- 
clavian artery, on the left the arch of the aorta. 128 
GENERAL ANATOMY. 
manent aorta. From the extremity of this the two vitelline arteries, which were 
originally parts of the primitive main trunks, pass to the area vasculosa. As the 
umbilical vesicle dwindles and the allantois grows, two large branches are formed as 
lateral offshoots of the median aorta. These are the two umbilical or hypogastric 
arteries, and are concerned in the placental circulation. The portion of the median 
aorta beyond this point becomes much diminished in size, and eventually forms the 
sacra-media artery, and thus the two umbilical branches become in appearance bifur- 
cating branches of the main aorta. The common and internal iliac arteries are 
developed from the proximal end of these umbilical arteries; the middle portion of 
the vessel after birth becomes partially atrophied, but in part remains pervious as the 
superior vesical artery; the distal portion becomes obliterated, constituting part of 
the superior ligament of the bladder. The external iliac and femoral arteries are 
developed from two small branches given off from the umbilical arteries near their 
origin, and are at first of comparatively small size. 
Development of the Veins.-The formation of the great veins of the embryo 
may be best considered under two groups, visceral and parietal. 
The visceral are derived from the vitelline and umbilical veins. In the earliest 
period of the circulation of the embryo we have seen that there were two veins (vitel- 
line or omphalo-mesenteric) returning the blood from the vitelline membrane. These 
unite together to form a single vitelline vein. As soon as begins to be 
formed two umbilical veins appear, and, uniting together, join the vitelline vein. We 
have thus a single trunk formed by four veins, two returning the blood from the area 
vasculosa, and two from the placenta. Soon, however, the right vitelline and right 
umbilical veins disappear. The trunk now receives only the left vitelline and umbili- 
cal veins in its passage to the heart, and it traverses the'rudimentary liver. Whilst 
doing so it gives off two sets of vessels: those nearer the heart (the vence hepaticce 
revehentes) eventually become the hepatic veins, while those more remote (the vence 
Fig. 104. 
Diagrams illustrating the Development of the Great Veins. The first figure shows the vertebral veins emptying 
into the heart by two lateral trunks, " the ducts of Cuvier." The second figure shows the formation of the 
iliac and subclavian veins : a, inferior vena cava; b, left innominate vein. The third figure shows the ver- 
tebral veins much diminished in size and the duct of Cuvier on the left side, gradually disappearing: c, vena 
azygos minor. The fourth figure shows the adult condition of the venous system: 1, right auricle of heart; 
2, vena cava superior; 3, jugular veins; 4, subclavian veins; 5, vena cava inferior; 6, iliac veins; 7, lumbar 
veins; 8, vena azygos major; 9, vena azygos minor; 10, superior intercostal vein (after Dalton). 
hepaticoe advehentes) are the radicles of the right and left portal veins. These ves- 
sels communicate by a capillary plexus in the substance of the liver, so that a por- 
tion of the blood passing to the heart through the united left vitelline and umbilical 
veins traverses the substance of the developing liver, passing to its capillaries by the DEVELOPMENT OF THE VEINS. 
129 
venae advehentes (rudimentary portal veins), and being returned by the venae reve- 
hentes (rudimentary hepatic veins). That portion of the common trunk of the 
united vitelline and umbilical veins which lies between these two sets of vessels 
becomes the ductus venosus, and that portion which lies between the junction with 
it of the venae revehentes and the heart becomes the upper part of the inferior vena 
cava. The distal part of the vitelline vein, receiving the veins from the mesentery, 
becomes the superior mesenteric vein, and is joined by the splenic, after which junc- 
tion it becomes the trunk of the portal vein. 
The Parietal Veins.-The first appearance of a parietal system consists in the 
appearance of two short transverse veins (the ducts of Cuvier) which open on either 
side of the auricular portion of the heart. Each of these ducts is formed by an 
ascending and descending vein. The ascending veins return the blood from the 
parietes of the trunk and the Wolffian bodies, and are called cardinal veins. The 
two descending ones return the blood (Fig. 104) from the head, and are called prim- 
itive jugular veins. As the kidneys are developed, the veins conveying the blood 
from them unite together to form a single trunk, which passes up the abdomen 
behind the intestines, and, joining the common trunk formed as above described by 
the junction of the left vitelline and left umbilical vein above the point of entrance 
of the venae revehentes, constitutes the inferior vena cava. Two small veins receiv- 
ing branches from the lower extrem- 
ity unite to form the lower part of the 
inferior vena cava below the point of 
entrance of the veins from the kid- 
neys. These are the primitive iliac 
veins, and in their course upward they 
cross the cardinal veins and commu- 
nicate with them. The part of the 
iliac vein between this point of com- 
munication and their junction with 
one another constitutes the common 
iliac vein, while the distal portion 
forms the external iliac vein. The 
internal iliac vein is formed from that 
part of the cardinal vein which lies 
below the point of communication. 
The greater part of the remainder of 
the cardinal vein-that is to say, of 
that portion above the iliac veins- 
becomes obliterated; a small part, 
however, at the upper extremity re- 
mains persistent, and becomes contin- 
uous with two new veins which are 
formed, one on either side of the ver- 
tebral column. These veins receive 
the intercostal and lumbar veins, and 
eventually form the azygos veins. 
They become joined by an oblique 
communicating branch, which crosses 
the middle line and constitutes the 
junction of the vena azygos minor 
with the vena azygos major. These 
veins are termed the posterior verte- 
bral veins of Rathke. The upper part of the left one, with its continuation, the 
cardinal vein, forms the superior intercostal of the left side. 
The veins first formed in the upper part of the trunk are, as above stated, the 
primitive jugular veins. Shortly, two small branches may be noticed opening into 
them near their termination; these form the subclavian and internal jugular veins. 
Fig. 105. 
Diagram of the Formation of the Main Systemic Veins: A, 
heart and venous system at the period when there are two 
venae cava? superiores, posterior view: 1, left superior 
cava; 2, right superior cava; 3, inferior cava; 4, left in- 
ferior cardinal; 5, right inferior cardinal; 6, right jugu- 
lar; 7, anastomosing branch between the jugulars (left 
innominata); 8, subclavian; 9. internal jugular; 10, ex- 
ternal jugular; 11, middle obliterated portion of the pos- 
terior cardinal veins; 12, newly-formed posterior verte- 
bral veins; 13, anastomosis between the two vertebrals- 
trunk of small azygos; 14, iliac veins, proceeding from 
anastomosis between the inferior cava and posterior car- 
dinals ; 15, crural; 16, hypogastric-originally the distal 
ends of the cardinals. 
B, heart and permanent veins, posterior view: 1, obliterated 
left superior cava; 6, right innominate; 7, left innom- 
inate; 8, subclavian; 10, jugular; 13, trunk of the small 
azygos; 17, coronary sinus receiving the coronary vein; 
18, superior intercostal; 19, superior small azygos ; 20, in- 
ferior small azygos. 130 
GENERAL ANATOMY. 
From the point of junction of these veins on the left side a communicating branch 
makes its appearance, running obliquely across the neck downward and to the right, 
to open into the primitive jugular vein of the right side below the point of entrance 
of the subclavian vein. At the same time, in consequence of the alteration in the 
position of the heart and its descent into the thorax, the direction of the ducts of 
Cuvier becomes altered, and they assume an almost vertical position. From the por- 
tion of the primitive jugular veins above the branch of communication the inter- 
nal jugulars are formed, except that part of the right one which lies between the 
point of entrance of the subclavian of this side and the termination of the com- 
municating branch, which becomes the right innominate vein. The communicating 
branch becomes the left innominate vein. The primitive jugular of the right side, 
below the communicating vein and the right duct of Cuvier, becomes the vena cava 
superior, into which the right cardinal (vena azygos major) enters. The lower part 
of the left primitive jugular and the left duct of Cuvier become almost entirely 
obliterated, except at the lower end, which remains as a fibrous band, or sometimes a 
small vein, and runs obliquely over the posterior surface of the left auricle. The 
termination of the left duct of Cuvier remains persistent, and forms the coronary 
sinus (Fig. 105). The foetal circulation will be described on a future page. 
Development of the Alimentary Canal.-The development of the intestinal 
cavity is, as shown on page 108, one of the earliest phenomena of embryonic life. 
The original intestine consists of an inflection of the hypoblast extending from one 
end of the embryo to the other, and is situated just below the primitive vertebral 
column. At either extremity it forms a closed tube in consequence of the cephalic 
and caudal flexures (p. 107); and this manifestly divides it into three parts: a front 
part, enclosed in the cephalic fold, called the fore-gut; a posterior part, enclosed in 
the caudal fold, the hind-gut; and a central part, or mid-gut, which at this time 
freely communicates with the umbilical vesicle (Fig. 106). The ends of the fore- 
and hind-gut do not communicate with the surface of the body, the buccal and anal 
Fig. 106. 
Diagrammatic Outline of a Longitudinal Vertical Section of the Chick on the fourth day: ep, epiblast; tm, 
somatic mesoblast; hy, hypoblast; vm, visceral mesoblast; «/, cephalic [anterior amniotic] fold; pf, caudal 
[posterior amniotic] fold; am, cavity of true amnion; ys, yolk-sac; i, intestine; s, stomach and pharynx; a, 
future anus, still closed; m, the mouth; me, the mesentery; al, the allantoid vesicle; pp, space between inner 
and outer folds of amnion; \yi, vitello-intestinal duct] (from Quain's Anatomy, Allan Thompson). 
orifices being subsequently formed by involutions of the epiblast, which later on 
form communications with the gut. From the fore-gut, the pharynx, oesophagus, 
stomach, and duodenum; from the hind-gut, a part of the rectum; and from the 
middle division, the rest of the intestinal tube,-are developed (Fig. 107). The 
changes which take place in the fore-gut are as follows: The middle portion becomes 
dilated to form the stomach, and undergoes a rotation to the right, so that the pos- 
terior border, by which it is attached to the vertebral column by a mesentery, is now 
directed to the left, and the anterior border to the right. At this time it is straight, 
but it soon undergoes a lateral curve or bend to the right at its upper end. It thus 
assumes an oblique direction, and the left border (originally the posterior or attached 
border) becomes inferior and forms the great curvature. The mesentery by which it DEVELOPMENT OF THE ALIMENTARY CANAL. 
131 
was attached forms the great omentum. The portion of the fore-gut above this dila- 
tation remains straight, forming the pharynx and oesophagus, and in consequence 
of the mesoblast being here undivided there is no serous investment to the dorsal 
part of the tube. Below this, division of the mesoblast has taken place, and the 
splanchnopleure forms the vascular 
and serous layers of the remainder of 
the intestinal canal, the space between 
this layer and the somatopleure con- 
stituting the pleuro-peritoneal cavity. 
The part of the fore-gut below the 
dilated stomach forms the duodenum, 
and in connection with this the liver 
and pancreas are developed. 
The hind-gut is also a closed tube, 
and from it the middle third of the rec- 
tum is developed, as well as the allan- 
tois (p. Ill), which will be again re- 
ferred to in connection with the devel- 
opment of the bladder. 
The mid-gut is at first an open 
cavity freely communicating with the 
umbilical vesicle. As the body-walls 
grow, this communication contracts 
very materially, though it still exists 
to a certain extent, and its open cav- 
ity becomes converted into a straight 
tube, still open where it communicates 
with the umbilical vesicle. This tube grows rapidly in length, and presents a primitive 
curve or loop downward and forward, and, in consequence of its growth exceeding that 
of the walls of the body-cavity, a portion of the loop protrudes into the stalk of the 
umbilical vesicle. At a subsequent period, however, the walls of the abdomen grow 
more rapidly than the intestine, which again recedes into the body-cavity. At a short 
distance below the most prominent point of this loop a diverticulum arises, which marks 
the separation between the large and small intestine. The lower part of this divertic- 
ulum forms the vermiform appendix ; the proximal part, by its continued growth, con- 
stitutes the caecum. After this the anterior or upper part of the gut, corresponding to 
the small intestine, rapidly increases in length, and about the eighth week becomes con- 
voluted. The lower or posterior part, corresponding to the large intestine, is at first 
less in calibre than the upper part, and lies wholly to the left side of the convolu- 
tions of the small intestine; but later on the curve of the large intestine begins to 
form, and the first part (ascending colon) slowly crosses over to the right side, first 
lying in the middle line, just below the liver. It is not until the sixth month that 
the caecum descends into the right iliac fossa, and so drags the ascending colon into 
its normal position in the right flank. 
The peritoneal cavity is the space left between the visceral and parietal layers 
of the mesoblast, and the serous membrane is developed from these structures. The 
mesenteries are formed from mesoblastic tissue extending between the notochord and 
the gut which develops the vascular and connective-tissue elements of these parts. 
The buccal cavity is formed by an involution of the external [epiblastic] layer 
of the blastodermic membrane, which passes inward and meets the pharynx or upper 
part of the fore-gut. The two cavities are, however, at first completely separated 
from each other by all the layers of the blastoderm ; but at an early period of devel- 
opment a vertical slit appears between them ; this gradually widens and becomes the 
opening by which the common cavity of the nose and mouth communicates with the 
pharynx. The common cavity is afterward divided into nose and mouth by the 
development of the palate in the manner spoken of above. 
The tongue appears about the fifth week as a small elevation behind the inferior 
Fig. 107. 
Early Form oi the Alimentary Canal (from Kolliker, after 
Bischoff): In A a front view, and in B an antero-poste- 
rior section, are represented : a, four pharyngeal or vis- 
ceral plates; b, the pharynx; c, c, the commencing lungs: 
d, the stomach; f, f, the' diverticula connected with the 
formation of the liver; g, the yolk-sac [umbilical vesicle/ 
into which the middle intestinal groove opens; h, the 
posterior part of the intestine. 132 
GENERAL ANATOMY. 
maxillary arch, to which another projection from the second pharyngeal arch is 
united. The epithelial layer is furnished by the epiblast. The tonsils appear 
about the fourth month. 
The anus is also formed by an inflection of the epiblast, which extends inward 
to a slight extent, and approaches the termination of the hind-gut, and finally com- 
municates with it by a solution of continuity in the septum between the two. The 
persistence of the foetal septum at either the buccal or anal orifice constitutes a 
well-known deformity-imperforate oesophagus or imperforate rectum, as the case 
may be. 
The liver appears after the Wolffian bodies, about the third week, in the form of 
a bifid mass of cells consisting of the hypoblastic and mesoblastic layers of the intes- 
tine. It projects from the intestine at that part which afterward forms the duode- 
num. This mass of cells becomes hollowed out into a cavity lined by hypoblast, 
the rudiment of the main duct of the liver, the cells on either side being developed 
into the right and left lobes. These grow very rapidly around the vein formed by 
the junction of the left umbilical and left allantoic veins, from which they receive 
the branches enumerated on p. 128. About the third month the liver almost fills 
the abdominal cavity. From this period the relative development of the liver is 
less active, more especially that of the left lobe, which now becomes smaller than 
the right; but the liver remains up to the end of foetal life relatively larger than in 
the adult. 
The gall-bladder appears about the second month as an extension of the cavity 
from which the main duct of the liver is developed, and bile is detected in the intes- 
tines by the third month. 
The pancreas is also an early formation, being far advanced in the second month. 
It, as well as the salivary glands, which appear about the same period, originates in 
a projection from the epithelial layer, which afterward forms a cavity, and the lob- 
ules of the gland are developed from the ramifications of this cavity. It is gener- 
ally admitted that the epithelial lining of the ducts is furnished by the hypoblast in 
the development of both the pancreas and the liver, and that the vessels owe their 
origin to the mesoblast. But authorities differ as to the mode of formation of the 
parenchyma-as to whether this is entirely of mesoblastic origin or whether the 
hypoblast shares in its development. The spleen, on the other hand, is apparently 
entirely of mesoblastic origin, for there is never any connection between the intes- 
tinal cavity and the substance of this organ. It originates from the mesenteric fold 
which connects the stomach to the vertebral column (mesogastrium). 
Development of the Respiratory Organs.-The lungs appear somewhat later 
than the liver. They are developed from a small median cul-de-sac or diverticulum 
from the upper part of the fore-gut, immediately behind the fourth visceral cleft, as 
a projection from the epithelial and fibrous lamime of the intestine. During the 
fourth week a pouch is formed on either side of the central diverticulum, and opens 
freely through it into the fore-gut (pharynx). From these, other secondary pouches 
are given off, so that by the eighth week the form of the lobes of the lungs may be 
made out. The two primary pouches have thus a common pedicle of communica- 
tion with the pharynx. This is developed into the trachea (Fig. 102, B, 1), the 
cartilaginous rings of which are perceptible about the seventh week. The parts 
which afterward form the larynx are recognized as early as the sixth week-viz. a 
projection on either side of the pharyngeal opening, the rudiment of the arytenoid 
cartilage, and a transverse elevation from the third pharyngeal arch, which afterward 
becomes the epiglottis; the vocal cords and ventricles of the larynx are seen about 
the fourth month. Traces of the diaphragm appear in the form of a fine mem- 
brane, separating the lungs from the Wolffian bodies, the stomach, and the liver, 
whilst the heart is still near the head. As the diaphragm extends forward from the 
vertebral column it separates the common pleuro-peritoneal cavity into two parts, a 
thoracic and abdominal. 
Development of the Urinary Organs.-The urinary organs appear to be 
entirely of mesoblastic origin, and are intimately connected with an embryonic DEVELOPMENT OF THE URINARY ORGANS. 
133 
glandular organ first discovered by Wolff, and hence called the Wolffian body. 
Recent researches have shown that the Wolffian bodies form a part of a set of 
organs which are found in all vertebrate and some invertebrate animals. These 
structures have been termed the segmental organs, and consist, in vertebrates, of 
branching tubes opening at one extremity into the body-cavity, and at the other by 
one or more main ducts into the cloaca or hind-gut.1 The segmental organs of 
vertebrates are divided into three parts, each of which possesses an excretory duct. 
The anterior of the three, situated in the region of the rudimentary heart, is termed 
the head-kidney or pronephros (Lankester), and its duct is the Mullerian duct. The 
central part is the Wolffian body, the mesonephros (Lankester), and its duct is the 
Wolffian duct. The posterior segment is the rudiment of the permanent kidney, 
and is formed later than the other two. It is named the metanephros (Lankester), 
and its duct is the ureter. 
The segmental duct is perceptible about the third week, forming an elongated 
ridge of cells situated on either side of the primitive vertebrae and extending from 
the heart to the lower end of the embryo. It makes its appearance below the heart 
and behind the common pleuro-peritoneal cavity, from the mesoblast at the point of 
separation of its two layers into somatopleure and splanchnopleure. As this ridge 
is situated in front of the epiblast (reflected from the medullary cavity) at the side 
of the protovertebrae and behind the common pleuro-peritoneal cavity, it has been 
named " the intermediate cell-mass." It is at first solid, but soon a tube is hollowed 
out in it by the formation of a lumen in its most prominent part; this is the seg- 
mental duct, the greater part of which forms the Wolffian duct. As the duct is 
formed it sinks downward and projects into the body-cavity. The remainder of the 
segmental organ-i. e. that part which is not concerned in the formation of the 
duct-becomes converted into tubes, which commence as branches from the duct 
and spread out at right angles with it. They are at first caecal [z. e. blind or closed], 
but soon acquire openings at their inner extremities into the body-cavity, the lower 
end of the segmental duct at the same time forming an opening into the urogenital 
sinus. Thus a communication is established through these tubes and duct between 
the pleuro-peritoneal cavity and the cloaca or hinder part of the alimentary canal. 
The next step is the formation of a second duct in the neighborhood of the original 
duct, with which some of the tubules of the anterior part of the segmental body 
(pronephros) are connected. This is the Mullerian duct. The ureter, which is 
formed later, is an offshoot from the hinder part of the Wolffian duct. 
The structure of the Wolffian body is in many respects analogous to that of the 
permanent kidney (Fig. 108). It is composed partly of an excretory canal or duct, 
into which open numerous "conduits," rectilinear at first, but afterward tortuous, 
and partly of a cellular or glandular structure, in which Malpighian tufts are found. 
It is fixed to the diaphragm by a superior ligament, and to the spinal column by an 
inferior or lumbar ligament. Its office is the same as that of the kidneys-viz. to 
secrete fluid containing urea which accumulates in the bladder. When the perma- 
nent kidneys are formed, the greater part of the Wolffian body disappears. The 
rest takes part in the formation of the organs of generation. 
The functional activity of the Wolffian bodies is very transitory ; they attain their 
highest development by the sixth week, after which time they begin to decrease in 
size, and have nearly disappeared by the end of the third month. The upper part 
of the segmental body, the pronephros, also undergoes atrophy and disappears. In 
the male the Wolffian duct persists, and becomes converted into the vas deferens; 
the Mullerian duct undergoes a,trophy, a vestige of it, however, remaining as the 
sinus prostaticus; whereas, on the other hand, in the female the Mullerian duct 
remains and becomes converted into the whole length of the genital passages, while 
the Wolffian duct almost entirely disappears and remains only as a vestige. Prior 
to this, however, the Wolffian and Mullerian ducts (together with the ureter when 
formed) open into the common urogenital sinus or cloaca, which is the termination 
of the intestinal cavity, into which the allantois also opens in front (Fig. 109). 
1 In invertebrates the external openings are on the sides of the body. 134 
GENERAL ANATOMY. 
As the allantois expands into the urinary bladder this common cavity is divided 
into two by a septum to form the bladder in front and the rectum behind. The 
Wolffian and Mullerian ducts are soon connected by cellular substance into a single 
mass-the genital cord-in which the Wolffian ducts lie side by side in front, and 
the ducts of Muller behind, at first separate, but later on uniting with each other. 
It has been stated that the kidney is developed from the lower part (metanephros) 
of the segmental organ. With this the ureter becomes connected in the following 
manner: It commences as a tubular di- 
verticulum from the lower part of the 
segmental duct close to the cloaca. It 
extends upward and becomes divided 
into a number of caecal tubules, which 
represent the commencement of the sev- 
eral divisions of the pelvis of the kid- 
ney. These tubules are prolonged into 
the solid blastema of which the kidney 
at that time consists. The tubules then 
become convoluted, and masses of cells 
accumulate on their exterior, so as to give 
to the organ an appearance of lobulation. 
Between these cells vessels are developed, 
and the vascular glomeruli are gradually 
Fig. 109. 
Fig. 108. 
Diagram of the Primitive Urogenital Organs in the 
Embryo previous to sexual distinction. The parts 
are shown chiefly in profile, but the Mullerian and 
Wolffian ducts are seen from the front: 3, ureter; 
4, urinary bladder; 5, urachus; ot, the mass of blas- 
tema from which ovary or testicle is afterward 
formed; W, left Wolffian body; x, part at the upper 
apex from which the coni vasculosi are afterward 
developed; w, w, right and left Wolffian ducts; m, m, 
right and left Mullerian ducts uniting together and 
with the Wolffian ducts in gc, the genital cord ; ug, 
sinus urogenitalis ; i, lower part of the intestine; 
cl, common opening of the intestine and urogenital 
sinus; cp, elevation which becomes clitoris or penis; 
Is, ridge from which the labia majora or scrotum 
is formed. 
Enlarged View from the Front of the Left Wolffian 
Body before the establishment of the distinction of 
sex (from Farre, after-Kobelt): a, a, b, d, tubular 
structure of the Wolffian body; e, Wolffian duct; 
f, its upper extremity ; g, its termination in x, the 
urogenital sinus; h, the duct of Muller; i, its upper, 
still closed, extremity; k, its lower end, terminating 
in the urogenital sinus; I, the mass of blastema for 
the reproductive organ, ovary or testicle. 
formed. The kidneys at first, therefore, consist of cortical substance only, but later 
on the proximal ends of the tubes become straight and arranged in bundles, and thus 
the pyramidal structure is developed. The lobulation of the kidney is perceptible for 
some time after birth. 
The urinary bladder, as before stated, is formed by a dilatation of the lower part 
of the stalk of the allantois. At the end of the second month this forms a spindle- 
shaped cavity, the bladder, which communicates with the lower part of the primitive 
intestine by a short canal, the first part of the urethra. The upper part of the stalk 
of the allantois, which is not dilated, forms the urachus; this extends up into the 
umbilical cord, and at an early period of embryonic existence forms a tube of com- 
munication with the allantois. It is obliterated before the termination of foetal life, 
but the cord formed by its obliteration is perceptible throughout life, passing from 
the upper part of the bladder to the umbilicus, and it occasionally remains patent 
in the adult, constituting a well-known malformation. 
The suprarenal bodies are developed from two different sources. The medullary 
part of the organ is of epiblastic origin, and is derived from the tissues forming the 
sympathetic ganglia of the abdomen, while the cortical portion is of mesoblastic ori- 
gin, and originates in the mesoblast just above the kidneys. The two parts are at DEVELOPMENT OF THE GENERATIVE ORGANS. 
135 
first quite distinct, but become combined in the process of development. The supra- 
renal capsules are at first larger than the kidney, but become equal in size about the 
tenth week, and from that time decrease relatively to the kidney, though they remain 
throughout foetal life much larger in proportion than in the adult. 
Development of the Generative Organs.-The first appearance of the repro- 
ductive organs is essentially the same in the two sexes, and consists in a thickening 
at one spot of the epithelial layer which lines the peritoneal or body-cavity, with a 
slight increase of the connective tissue beneath it, forming a low ridge. This is 
termed the genital ridge, and is situated on the mesial side of each Wolffian body, 
and from it the testicle in the one sex and the ovary in the other are developed. 
The ridge as the embryo grows gradually becomes pinched off" from the Wolffian 
body, with which it is at first continuous, though it still remains connected to the 
remains of this body by a fold of peritoneum, the mesorchium or mesovarium. 
About the seventh week the distinction of sex begins to be perceptible. The epi- 
thelium on the genital ridge, which is called "germ-epithelium," in the female 
becomes distinctly columnar, multiplies rapidly, and begins to form primitive ova 
in a manner presently to be described; whereas in the male, though the germ- 
epithelium has a tendency to become columnar, the cells are on the whole flatter 
and smaller than in the female. 
Development of Male Organs.-The tubuli seminiferi of the testicle appear 
at an early period. It is believed that they are formed by the extension of epithe- 
lial cells on the surface of the genital ridge into its blastema; rows of cells are thus 
developed which become the lining cells of the seminal ducts. In some animals 
(e. g. reptiles) the segmental tubes of the Wolffian body have been found to extend 
into the body of the testis and to form the tubes of this organ, which become lined 
with cells derived from the germ-epithelium; and it is probable that a similar pro- 
cess takes place in birds and mammals. 
The Mullerian ducts disappear in the male sex, with the exception of their lower 
ends. These unite in the middle line, and open by a common orifice into the uro- 
genital sinus. This constitutes the utriculus hominis or sinus pro stations. Occa- 
sionally, however, the upper end of the duct of Muller remains visible in the male, 
constituting the little pedunculated body called the hydatid of Morgagni, sometimes 
found in the neighborhood of the epididymis,1 between the testes and globus major. 
The head of the epididymis, its canal, the vas deferens, and the ejaculatory duct 
are formed from the canals and duct of the Wolffian body. One or more of the 
tubes of the Wolffian body form the vas aberrans and a structure described by 
Giraldes, and called, after' him, "the organ of Giraldes," which bears a good deal 
of resemblance to the organ of Rosenmuller in the other sex. It consists of a 
number of convoluted tubules lying in the cellular tissue in front of the cord and 
close to the head of the epididymis. 
The descent of the testis and the formation of the gubernaculum are described 
in the body of the work. 
Development of Female Organs.-The ovary, as above stated, is formed from 
the genital ridge, which becomes pinched off from the remains of the Wolffian body, 
but is still attached by a mesovarium. It consists of a central part of connective 
tissue covered by a layer of germ-epithelium, from which the ova are developed. 
This epithelium undergoes repeated division, so that it rapidly increases in thick- 
ness and forms several layers. Next, certain of the cells become enlarged and 
spherical, and form what are called the primitive ova. Around these other epithe- 
lial cells have a tendency to arrange themselves so as to enclose the ovum in a fol- 
licle. The permanent ova, enclosed in their Graafian follicles, are thus formed. 
The Fallopian tube is developed from that portion of the duct of Muller which 
lies above the lumbar ligament of the Wolffian body. This duct is at first com- 
plete!}/ closed at its upper extremity, and this closed extremity remains permanent, 
forming a small cystic body attached to the fimbriated end of the Fallopian tube, 
1 Mr. Osborn, in the St. Thomas's Hospital Reports, 1875, has written an interesting paper pointing 
out the probable connection between this foetal structure and one form of hydrocele. 136 
GENERAL ANATOMY. 
and called the "hydatid of Morgagni." Below this a cleft forms in the duct, and 
is developed into the fimbriated opening of the Fallopian tube. 
Below this the duct of Muller and the ducts of the Wolffian bodies are united 
together in a structure called "the genital cord," in which the two Mullerian ducts 
approach each other, lying side 
by side, and finally coalesce to 
form the cavity of the vagina 
and uterus. This coalescence 
commences in the middle of the 
genital cord, and corresponds to 
the body of the uterus. The 
upper parts of the Mullerian 
ducts in the genital cord con- 
stitute the cornua of the uterus, 
little developed in the human 
species. The only remains of 
the Wolffian body in the com- 
plete condition of the female 
organs are two rudimentary or 
vestigial structures, which can 
be found, on careful search, in 
the round ligament near the 
ovary - the parovarium or or- 
gan of Rosenmuller and the 
epobphoron (Fig. 110). The 
organ of Rosenmuller consists of a number of tubes which converge to a transverse 
portion (the epobphoron), and this is sometimes prolonged into a distinct duct run- 
ning transversely, the duct of Gartner, which is much more conspicuous and extends 
farther in some of the lower animals. This is the remains of the Wolffian duct. 
About the fifth month an annular constriction marks the position of the neck of the 
uterus, and after the sixth month the walls of the uterus begin to thicken. The 
Fig. 110. 
Adult Ovary, Parovarium, and Fallopian Tube (from Farre after 
Kobelt): a, a, epobphoron (parovarium), formed from the upper 
part of the Wolffian body; b, remains of the uppermost tubes, 
sometimes forming hydatids; c, middle set of tubes; d, some 
lower atrophied tubes; e, atrophied remains of the Wolffian 
duct; f, the terminal bulb or hydatid; h, the Fallopian tube, 
originally the duct of Muller; i, hydatid attached to the extrem- 
ity ; I, the ovary. 
Fig. 111. 
Female Genital Organs of the Embryo, with the remains of the Wolffian bodies (after J. Muller): A, from a 
foetal sheep: a, the kidneys; b, the ureters; c, the ovaries; d, remains of Wolffian bodies; e, Fallopian 
tubes ; f, their abdominal openings; g, their union in the body of the uterus. B. more advanced, from a 
foetal deer; a, body of the uterus; b, cornua; c, tubes; d, ovaries; e, remains of Wolffian bodies. C, still 
more advanced, from the human foetus of three months : a, the body of the uterus; b, the round ligament; 
c, the Fallopian tubes; d, the ovaries; e, remains of the Wolffian bodies. 
round ligament is derived from the lumbar ligament of the Wolffian body; the peri- 
toneum constitutes the broad ligament; the superior ligament of the Wolffian body 
disappears with that structure (Fig. 111). DEVELOPMENT OF GENERATIVE ORGANS. 
137 
The external organs of generation, like the internal, pass through a stage in 
which there is no distinction of sex (Fig. 112, n, in). We must therefore describe 
this stage, and then follow the development of the female and male organs respec- 
tively. 
As stated above, the anal depression at an early period is formed by an involu- 
tion of the external epithelium, and the intestine is still closed at its lower end. 
Fig. 112. 
Bevelopment of the External Genital Organs. Indifferent type, i, n, m.-Female: A and B, at the middle of the 
hfth month: C, at the beginning of the sixth.-Male: A', at the beginning of the fourth month; B', at the 
uiidale of the fourth month; C , at the end of the fourth month. 1, cloaca; 2, genital tubercle; 3, glans 
penis or clitoris; 4, genital furrow; 5, external genital folds (labia majora or scrotum); 6, umbilical cord; 
7, anus; 8, caudal extremity and coccygeal tubercle; 9, labia minora; 10, urogenital sinus; 11, fcmim cli- 
tondis; 12, preputium penis or clitoridis; 13, opening of the urethra ; 14, opening of the vagina; 15, hymen; 
16, scrotal raphS. , j , 
When the septum between the two opens, which is about the fourth week, the 
urachus in front and the intestine behind both communicate with the anal depres- 
sion. This, which is now called the cloaca, is afterward divided by a vertical trans- 138 
GENERAL ANATOMY. 
verse septum, the perineum, which appears about the second month. Two tubes are 
thus formed: the posterior becomes the lower part of the rectum, the anterior is the 
urogenital sinus. In the sixth week a tubercle, the genital tubercle, is formed in 
front of the cloaca, and this is soon surrounded by two folds of skin, the genital 
folds. Toward the end of the second month the tubercle presents, on its lower 
aspect, a groove, the genital furrow, turned toward the cloaca. All these parts 
are well developed by the second month, yet no distinction of sex is possible. 
Female Organs (Fig. 112, A, B, c).-The female organs are developed by an easy 
transition from the above. The- urogenital sinus persists as the vestibule of the 
vagina, and forms a single tube with the upper part of the vagina, which, as we 
have already seen, is developed from the united Mullerian ducts. The genital 
tubercle forms the clitoris, the genital folds the labia majora, and the lips of the 
genital furrow the labia minora, which remain open. 
Male Organs.-In the male the changes are greater. The genital tubercle is 
developed into the penis, the glans appearing in the third month, the prepuce and 
corpora cavernosa in the fourth. The genital furrow closes, and thus forms a canal, 
the spongy portion of the urethra. The urogenital sinus becomes elongated, and 
forms the prostatic and membranous urethra. The genital folds unite in the middle 
line to form the scrotum, at about the same time as the genital furrow closes-viz. 
between the third and fourth months. 
The following table is translated from the work of Beaunis and Bouchard, with 
some alterations, especially in the earlier weeks. It will serve to present a resumS 
of the above facts in an easily accessible form.1 
1 It will be noticed that the time assigned in this table for the appearance of the first rudiment of 
some of the bones varies in some cases from that assigned in the description of the various bones in 
the sequel. This is a point on which anatomists differ, and which probably varies in different cases. CHRONOLOGICAL TABLE 
OF 
THE DEVELOPMENT OF THE FCETUS. 
(From Beaunis and Bouchard.) 
First Week.-During this period the ovum is in the Fallopian tube. Having been fertilized in 
its upper part, it slowly passes down, undergoing segmentation, and reaches the uterus 
probably about the end of the first week. During this time it does not undergo much 
increase in size. 
Second Week.-The ovum rapidly increases in size, and becomes imbedded in the decidua, so 
that it is completely enclosed in the decidua reflexa by the end of this period. An ovum 
believed to be of the thirteenth day after conception is described by Reichert. There was 
no appearance of any embryonic structure. The equatorial margins of the ovum were 
beset with villi, but the surface in contact with the uterine wall and the one opposite to it 
were bare. In another ovum, described by His, believed to be of about the fourteenth day, 
there was a distinct indication of an embryo. There was a medullary groove bounded by 
folds. In front of this a slightly prominent ridge, the rudimentary heart. The amnion was 
formed, and the embryo was attached by a stalk, the allantois, to the inner surface of the 
chorion. It may be said, therefore, that these parts, the amnion and the allantois, and the 
first rudiments of the embryo, the medullary groove and the heart, are formed at the end of 
the second week. 
Third Week.-By the end of the third week the flexures of the embryo have taken place, so that 
it is strongly curved. The protovertebral disks, which begin to be formed early in the third 
week, present their full complement. In the nervous system the primary divisions of the 
brain are visible, and the primitive ocular and auditory vesicles are already formed. The 
primary circulation is established. The alimentary canal presents a straight tube commu- 
nicating with the yolk-sac. The pharyngeal arches are formed. The limbs have appeared 
as short buds. The Wolffian bodies are visible. 
Fourth Week.-The umbilical vesicle has attained its full development. Projection of the caudal 
extremity. Projection of the upper and lower limbs. Cloacal aperture. The heart sepa- 
rates into a right and left heart. Spinal ganglia and anterior roots. Olfactory fossae. 
Lungs. Pancreas. 
Fifth Week.-Vascularity of the allantois in its whole extent. First trace of hands and feet. 
The primitive aorta divides into primitive aorta and pulmonary artery. Conduit of Muller 
and genital gland. Ossification of clavicle and lower jaw. Cartilage of Meckel. 
Sixth Week.-The activity of the umbilical vesicle ceases. The pharyngeal clefts disappear. 
The vertebral column, primitive cranium, and ribs assume the cartilaginous condition. 
Posterior roots of the nerves. Membranes of the nervous centres. Bladder. Kidneys. 
Tongue. Larynx. Thyroid gland. Germs of teeth. Genital tubercle and folds. 
Seventh Week.-The muscles begin to be perceptible. Points of ossification of the ribs, scapula, 
shafts of humerus, femur, tibia, intermaxillary bone, palate, upper jaw (its first four points). 
Eighth Week.-Distinction of arm and forearm and of thigh and leg. Appearance of the inter- 
digital clefts. Capsule of the lens and pupillary membrane. Completion of the interven- 
tricular and commencement of the interauricular septum. Salivary glands. Spleen. Supra- 
renal capsules. The larynx begins to become cartilaginous. All the vertebral bodies are 
cartilaginous. Points of ossification for the ulna, radius, fibula, and ilium. The two halves 
of the bony palate unite. Sympathetic nerve. 
Ninth Week.-Corpus striatum. Pericardium. Distinction between ovary and testicle. Forma- 
tion of the genital furrow. Osseous nuclei of vertebral bodies and arches, frontal, vomer, 
malar bone, shafts of metacarpal bones, metatarsal bones, and phalanges. The union of 
the hard palate is completed. Gall-bladder. 
Third Month.-Formation of the foetal placenta. The projection of the caudal extremity disap- 
pears. It is possible to distinguish the male and female organs at the commencement of the 
third month. The cloacal aperture divided into two parts. The cartilaginous arches on the 
dorsal region of the spine close. Points of ossification for the occipital, sphenoid, os unguis, 
139 140 
TABLE OF DEVELOPMENT OF THE FOETUS. 
nasal bones, squamous portion of temporal and ischium. Orbital centre of superior maxil- 
lary bone. Commencement of formation of maxillary sinus. Pons Varolii. Fissure of 
Sylvius. Formation of eyelids and of hair and nails. Mammary gland. Epiglottis. Union 
of the testicle with the canals of the Wolffian body. Prostate. 
Fourth Month.-The closure of the cartilaginous arches of the spine is complete. Osseous points 
for the first sacral vertebra and pubes. Ossification of the malleus and incus. Corpus cal- 
losum. Membranous lamina spiralis ; cartilage of the Eustachian tube. Tympanic ring. 
Fat in subcutaneous cellular tissue. Tonsils. Closure of genital furrow and formation of 
scrotum arid prepuce. 
Month.-The two layers of decidua begin to coalesce. Osseous nuclei of axis and odontoid 
process. Lateral points of first sacral vertebra; median points of second. Osseous points 
of lateral masses of ethmoid. Ossification of stapes and petrous bone. Ossification of 
germs of teeth. Appearance of germs of permanent teeth. Organ of Corti. Eruption 
of hair on head. Sudoriferous glands. Glands of Brunner. Follicles of tonsils and 
base of tongue. Lymphatic glands. Commencement of limitation of uterus and vagina. 
Sixth Month.--Points of ossification for the anterior root of the transverse process of the sev- 
enth cervical vertebra. Lateral points of second sacral vertebra; median points of third. 
The sacro-vertebral angle forms. Osseous points of the manubrium sterni and of the os 
calcis. The cerebral hemisphere covers the cerebellum'. Papillae of the skin. Sebaceous 
glands. The free border of the nail projects from the corium of the dermis. Peyer's patches. 
The walls of the uterus thicken. 
Seventh Month.-Additional points of first sacral vertebra; lateral points of third; median point 
of fourth. First osseous point of body of sternum. Osseous point for astragalus. Disap- 
pearance of Meckel's cartilage. Cerebral convolutions. Insula of Beil. Separation of 
tubercula quadrigemina. Disappearance of pupillary membrane. The testicle passes into 
the vaginal process of the peritoneum. 
Eighth Month.-Additional points for the second sacral vertebra ; lateral points for the fourth ; 
median points for the fifth. 
Ninth Month.-Additional points for the third sacral vertebra; lateral points for the fifth. Osse- 
ous point for the middle turbinated bone; for the body and great cornu of the hyoid; for 
the second and third pieces of the body of the sternum; for the lower end of the femur. 
Ossification of the bony lamina spiralis and axis of the cochlea. Opening of the eyelids. 
The testicles are in the scrotum. DESCRIPTIVE AND SURGICAL ANATOMY. 
The Skeleton. 
THE entire skeleton in the adult consists of two hundred distinct bones. These 
are- 
The Spine or vertebral column (sacrum and. coccyx included) 26 
Cranium 8 
Face 14 
Os hyoides, sternum, and ribs 26 
Upper extremities 64 
Lower extremities 62 
200 
In this enumeration the patellae are included as separate bones, but the smaller sesa- 
moid bones and the ossicula auditus are not reckoned. The teeth belong to the 
tegumentary system. 
These bones are divisible into four classes-Long, Short, Flat, and Irregular. 
The Long Bones are found in the limbs, where they form a system of levers 
which have to sustain the weight of the trunk and to confer the power of locomotion. 
A long bone consists of a shaft and two extremities. The shaft [or diaphysis] is a 
hollow cylinder, contracted and narrow to afford greater space for the bellies of the 
muscles; the walls consist of dense, compact tissue of great thickness in the middle, 
which becomes thinner toward the extremities; the spongy tissue is scanty, and the 
bone is hollowed out in its interior to form the medullary canal. The extremities 
[or epiphyses] are generally somewhat expanded, for greater convenience of mutual 
connection, for the purposes of articulation, and to afford a broad surface for muscu- 
lar attachment. Here the bone is made up of spongy tissue, with only a thin coat- 
ing of compact substance. The long bones are not straight, but curved, the curve 
generally taking place in two directions, thus affording greater strength to the bone. 
The bones belonging to this class are the humerus, radius, ulna, femur, tibia, fibula, 
metacarpal and metatarsal bones, and the phalanges. The clavicle is also usually 
reckoned as a long bone. 
Short Bones.-Where a part of the skeleton is intended for strength and com- 
pactness, and its motion is at the same time slight and limited, it is divided into a 
number of small pieces united together by ligaments, and the separate bones are 
short and compressed, such as the bones of the carpus and tarsus. These bones, in 
their structure, are spongy throughout, excepting at their surface, where there is a 
thin crust of compact substance. The patelice also, together with the other sesamoid 
bones, are by some regarded as short bones. 
Flat Bones.-Where the principal requirement is either extensive protection or 
the provision of broad surfaces for muscular attachment, we find the osseous structure 
expanded into broad flat plates, as is seen in the bones of the skull and the shoulder- 
blade. These bones are composed of two thin layers of compact tissue enclosing 
between them a variable quantity of cancellous tissue. In the cranial bones these 
layers of compact tissue are familiarly known as the tables of the skull: the outer 
one is thick and tough, the inner one thinner, denser, and more brittle, and hence 
141 142 
THE SKELETON. 
termed the vitreous tabled The intervening cancellous tissue is called the diploe. The 
flat bones are the occipital, parietal, frontal, nasal, lachrymal, vomer, scapula, os 
innominatum, sternum, ribs, and patella. 
The Irregular or Mixed Bones are such as, from their peculiar form, cannot be 
grouped under any of the preceding heads. The structure is similar to that of 
other bones, consisting of a layer of compact tissue externally and of spongy can- 
cellous tissue within. The irregular bones are the vertebrce, sacrum, coccyx, tem- 
poral, sphenoid, ethmoid, malar, superior maxillary, inferior maxillary, palate, 
inferior turbinated, and hyoid. 
Surfaces of Bones.-If the surface of any bone is examined, certain eminences 
and depressions are seen, to which descriptive anatomists have given the following 
names: 
A prominent process projecting from the surface of a bone, which it has never 
been separate from or movable upon, is termed an apophysis (from dnodmap, an 
excrescence); but if such process is developed as a separate piece from the rest of 
the bone, to which it is afterward joined, it is termed an epiphysis (from 
an accretion). 
These eminences and depressions are of two kinds-articular and non-articular. 
Well-marked examples of articular eminences are found in the heads of the humerus 
and femur, and of articular depressions in the glenoid cavity of the scapula and the 
acetabulum. Non-articular eminences are designated according to their form. Thus, 
a broad, rough, uneven elevation is called a tuberosity ; a small, rough prominence, 
a tubercle ; a sharp, slender, pointed eminence, a spine ; a narrow, rough elevation 
running some way along the surface, a ridge or line. 
The non-articular depressions are also of very variable form, and are described 
as fossce, grooves, furrows, fissures, notches, etc. These non-articular eminences 
and depressions serve to increase the extent of surface for the attachment of liga- 
ments and muscles, and are usually well marked in proportion to the muscularity of 
the subject. 
THE SPINE. 
The Spine is a flexuous and flexible column formed of a series of bones called 
Vertebrce (from vertere, to turn). 
The Vertebrae are thirty-three in number, exclusive of those which form the 
skull, and have received the names cervical, dorsal, lumbar, sacral, and coccygeal, 
according to the position which they occupy; seven being found in the cervical 
region, twelve in the dorsal, five in the lumbar, five in the sacral, and four in the 
coccygeal. [The movable vertebrae can be readily distinguished as follows: Every 
cervical vertebra has a foramen in the transverse processes, every dorsal vertebra 
has a facet, or one or two half-facets, on each side of the body for the ribs ; a lumbar 
vertebra has neither foramen nor facet.] 
This number is sometimes increased by an additional vertebra in one region, or 
the number may be diminished in one region, the deficiency being supplied by an 
additional vertebra in another. These observations do not apply to the cervical 
portion of the spine, the number of bones forming which is seldom increased or 
diminished. 
The vertebrae in the upper three regions of the spine are separate throughout 
the whole of life; but those found in the sacral and coccygeal regions are, in the 
adult, firmly united, so as to form two bones-five entering into the formation of the 
upper bone, or sacrum, and four into the terminal bone of the spine, or coccyx. 
1 Some authors have denied that the inner table is more brittle than the outer one. They state 
that the supposition has arisen from the fact that when the skull is fractured by a blow, or when a 
foreign body, such as a bullet, enters the skull, the inner table will often be found to be more splin- 
tered than the outer one. They affirm, however, that this is due to the direction in which the force 
is applied. If the force act in the opposite direction, then the condition of things would be reversed, 
and the outer table would be found to be more extensively fractured than the inner. (See some 
experiments by Mr. Teevan, Path. Soc. Trans., vol. xvi. p. 217, 1865.) CHARACTERS OF A VERTEBRA. 
143 
General Characters of a Vertebra. 
Each Vertebra consists of two essential parts-an anterior solid segment, or 
body, and a posterior segment, or arch. The arch is formed of two pedicles and two 
lamince, supporting seven processes-viz. four articular, two transverse, and one 
spinous process. 
The Bodies of the vertebrae are piled one upon the other, forming a strong pillar 
for the support of the cranium and trunk, the arches forming a hollow cylinder 
behind for the protection of the spinal cord. The different vertebrae are connected 
together by means of the articular processes and the intervertebral cartilages, while 
the transverse and spinous processes serve as levers for the attachment of muscles 
which move the different parts of the spine. Lastly, between each pair of vertebrae 
apertures exist through which the spinal nerves pass from the cord. Each of these 
constituent parts must now be separately examined. 
The Body, or centrum, is the largest and most solid part of a vertebra. Above 
and below it is flattened, presenting a rim around its circumference ; and its upper 
and lower surfaces are rough, for the attachment of the intervertebral fibro-carti- 
lages. In front it is convex from side to side, concave from above downward. 
Behind, it is flat from above downward, and slightly concave from side to side. 
Its anterior surface is perforated by a few small apertures for the passage of nutrient 
vessels, whilst on the posterior surface is a single large irregular aperture, or occa- 
sionally more than one, for the exit of veins from the body of the vertebra-the 
vence basis vertebrce. 
The Pedicles project backward, one on each side, from the upper part of the 
body of the vertebra, at the line of junction of its posterior and lateral surfaces. 
The concavities above and below the pedicles are the intervertebral notches ; they 
are four in number, two on each side, the inferior ones being generally the deeper. 
When the vertebrae are articulated the notches of each contiguous pair of bones form 
the intervertebral foramina, which communicate with the spinal canal and transmit 
the spinal nerves and blood-vessels. 
The Laminae are two broad plates of bone which complete the vertebral arch 
behind, enclosing a foramen [the which serves for the protection of 
the spinal cord; they are connected to the body by means of the pedicles. Their 
upper and lower borders are rough, for the attachment of the ligamenta subflava. 
The Articular Processes, four in number, two on each side, spring from the 
junction of the pedicles with the laminae. The two superior project upward, their 
articular surfaces being directed more or less backward; the two inferior project 
downward, their articular surfaces looking more or less forward.1 
The Spinous Process projects backward from the junction of the two laminae, 
and serves for the attachment of muscles. 
The Transverse Processes, two in number, project one at each side from the 
point where the articular processes join the pedicle. They also serve for the attach- 
ment of muscles. 
Character of the Cervical Vertebrae (Fig. 113). 
The Body is smaller than in any other region of the spine, and broader from 
side to side than from before backward. The anterior and posterior surfaces are 
flattened and of equal depth; the former is placed on a lower level than the latter, 
and its inferior border is prolonged downward, so as to overlap the upper and fore 
part of the vertebra below. Its upper surface is concave transversely, and presents 
a projecting lip on each side, its lower surface being convex from side to side, con- 
cave from before backward, and presenting laterally a shallow concavity, which 
receives the corresponding projecting lip of the adjacent vertebra. The pedicles are 
directed obliquely outward, and the superior intervertebral notches are deeper, but 
1 It may, perhaps, be as well to remind the reader that the direction of a surface is determined 
by that of a line drawn at right angles to it. 144 
THE SKELETON. 
narrower, than the inferior. The lamince are narrow, long, thinner above than 
below, and overlap each other, enclosing the spinal foramen, which is very large and 
of a triangular form. The spinous processes are short and bifid at the extremity, 
to afford greater extent of surface for the attachment of muscles, the two divisions 
being often of unequal size. They increase in length from the fourth to the seventh. 
Fig. 113. 
interior Tuibercle of Trant.Proc,' 
Transverse Process. 
Poftf/riorTuhcrcle of Trans. Proe. 
Foramen for Vertebral Art ?. 
Spinal Foramen 
Articular Process 
-InferiorArticular Process 
I Spin oust 
i Process- 
Cervical Vertebra. 
The transverse processes are short, directed downward, outward, and forward, bifid 
at their extremity, and marked by a groove along their upper surface, which runs 
downward and outward from the superior intervertebral notch, and serves for the 
transmission of one of the cervical nerves. They are situated in front of the artic- 
ular processes and on the outer side of the pedicles. The transverse processes are 
pierced at their base by a foramen, for the transmission of the vertebral artery, vein, 
and plexus of nerves. Each process is formed by two roots : the anterior root arises 
from the side of the body, and is the homologue of the rib in the dorsal region of 
the spine. The posterior root springs from the junction of the pedicle with the 
lamina, and corresponds with the transverse processes in the dorsal region. It is 
by the junction of the two that the foramen for the vertebral vessels is formed. 
The extremity of each of these roots forms the anterior and posterior tubercles of 
the transverse processes.1 The articular processes are oblique : the superior are of 
an oval form, flattened and directed upward and backward, the inferior downward 
and forward. 
The peculiar vertebrae in the cervical region are the first, or Atlas ; the second, 
or Axis ; and the seventh, or Vertebra prominens. The great modifications in the 
form of the atlas and axis are designed to admit of the nodding and rotatory move- 
ments of the head. 
The Atlas (Fig. 114) is so named from supporting the globe of the head. The 
chief peculiarities of this bone are that it has neither body nor spinous process. 
The body is detached from the rest of the bone, and forms the odontoid process of 
the second vertebra, while the parts corresponding to the pedicles pass in front 
and join to form the anterior arch. The atlas consists of an anterior arch, a 
posterior arch, and two lateral masses. The anterior arch forms about one-fifth 
of the bone: its anterior surface is convex, and presents about its centre a tubercle, 
for the attachment of the Longus colli muscle; posteriorly it is concave, and 
marked by a smooth oval or circular facet, for articulation with the odontoid process 
of the axis. The upper and lower borders give attachment to ligaments which con- 
nect it with the occipital bone above and the axis below. The posterior arch forms 
1 The anterior tubercle of the transverse process of the sixth cervical vertebra is of large size, and 
is sometimes known as " Chassaignac's, or the carotid tubercle." It is in close relation with the 
carotid artery, which lies in front and a little external to it; so that, as was first pointed out by 
Chassaignac, the vessel can with ease be compressed against it. CERVICAL VERTEBRAE. 
145 
about two-fifths of the circumference of the bone; it terminates behind in a tubercle, 
which is the rudiment of a spinous process and gives origin to the Rectus capitis 
posticus minor. The diminutive size of this process prevents any interference in 
the movements between it and the cranium. The posterior part of the arch presents 
above and behind a rounded edge for the attachment of a ligament, whilst in front 
immediately behind each superior articular process, is a groove, sometimes conceited 
into a foramen by a delicate bony spicula which arches backivaid fiom the poste- 
rior extremity of the superior articular process. These grooves represent the supe- 
rior intervertebral notches, and are peculiar from being situated behind the articular 
processes, instead of before them, as in the other vertebrae. They serve for the 
transmission of the vertebral artery, which, ascending through the foramen m the 
transverse process, winds round the lateral mass m a direction backward and inward. 
Fig. 114. 
Tubercle- 
foramen Tor 
Vertebral Art?. 
Trans. Procs- 
Groove fcrVor&o6. Art •> 
and *2 Cerv.Nervo 
S_pin. Proc., 
First Cervical Vertebra, or Atlas. 
They also transmit the suboccipital nerves. On the under surface of the posterior 
arch, in the same situation, are two other grooves, placed behind the lateral masses 
and representing the inferior intervertebral notches of other vertebrae. They are 
much less marked than the superior. The lower border also gives attachment to a 
ligament, which connects it with the axis. The lateral masses are the most bulky 
and solid parts of the atlas, in order to support the weight of the head; they pre- 
sent two articulating processes above and two below. The two superior are of large 
size, oval, concave, and approach toward one another in front, but diverge behind; 
they are directed upward, inward, and a little backward, forming a kind of cup for 
the condyles of the occipital bone, and are admirably adapted to the nodding move- 
ments of the head. Not unfrequently they are partially subdivided by a more or 
less deep indentation which encroaches upon each lateral margin. The inferior 
articular processes are circular in form, flattened or slightly concave, and directed 
downward and inward, articulating with the axis and permitting the rotatory move- 
ments. Just below the inner margin of each superior articular surface is a small 
tubercle, for the attachment of a ligament which, stretching across the ring of the 
atlas, divides it into two unequal parts, the anterior or smaller segment receiving 
the odontoid process of the axis, the posterior allowing the transmission of the spinal 
cord and its membranes. This part of the spinal canal is of considerable size, to 
afford space for the spinal cord, and hence lateral displacement of the atlas may 
occur without compression of the spinal cord. The transverse processes are of large 
size, project directly outward from the lateral masses, and serve for the attachment 
of special muscles which assist in rotating the head. They are long, not bifid, and 
perforated at their base by a canal for the vertebral artery, which is directed from 
below, upward and backward. 
The Axis (Fig. 115) is so named from forming the pivot upon which the head 
rotates. The most distinctive character of this bene is the strong prominent pro- 146 
THE SKELETON. 
cess, tooth-like in form (hence the name odontoid}, which rises perpendicularly from 
the upper part of the body. The body is of a triangular form, deeper in front than 
behind, and prolonged downward anteriorly so as to overlap the upper and fore part 
of the adjacent vertebra. It presents in front a median longitudinal ridge, separat- 
Fig. 115. 
Odontoid Pros, 
Rough Surf, far Cft ee/e LigF- 
Artec. Surf, for Trans. Ligt 
-Artic. Surf.for Atlas 
Spin. Proc. 
B ody 
.Proe. 
Lifer. A. rtie.Proo. 
Second Cervical Vertebra, or Axis. 
ing two lateral depressions for the attachment of the Longus colli muscle of either 
side. The odontoid process presents two articulating surfaces: one in front, of an 
oval form, for articulation with the atlas; another behind, for the transverse liga- 
ment, the latter frequently encroaching on the sides of the process. The apex is 
pointed; just below it the process is somewhat enlarged, and presents on either side 
a rough impression, for the attachment of the odontoid or check ligaments, which 
connect it to the occipital bone; 
the base of the process, where it is 
attached to the body, is constricted, 
so as to prevent displacement from 
the transverse ligament, which binds 
it in this situation to the anterior 
arch of the atlas. Sometimes, how- 
ever, this process does become dis- 
placed, especially in children, in 
whom the ligaments are more re- 
laxed : instant death is the result 
of this accident. The pedicles are 
broad and strong, especially their 
anterior extremities, which coalesce 
with the sides of the body and the 
root of the odontoid process. The 
lamince are thick and strong, and 
the spinal foramen large, but smaller 
than that of the atlas. The supe- 
rior articular surfaces are round, 
slightly convex, directed upward 
and outward, and are peculiar in 
being supported on the body, pedi- 
cles, and transverse processes. The inferior articular surfaces have the same direc- 
tion as those of the other cervical vertebrae. The superior intervertebral notches are 
very shallow, and lie behind the articular processes ; the inferior in front of them, as 
in the other cervical vertebrae. The transverse processes are very small, not bifid, 
and perforated by the vertebral foramen or foramen for the vertebral artery, which 
Fig. 116. 
Body. 
Spinal 
.'Foramen.. 
Seventh Cervical Vertebra, or Vertebra Prominens. 
Spin.au. s Bjycefi. DORSAL VERTEBRAE. 
147 
is directed obliquely upward and outward. The spinous process is of large size, 
very strong, deeply channelled on its under surface, and presents a bifid tubercular 
extremity for the attachment of muscles, which serve to rotate the head upon the 
spine. 
Seventh Cervical (Fig. 116).-The most distinctive character of this vertebra 
is the existence of a very long and prominent spinous process; hence the name 
"vertebra prominens." This process is thick, nearly horizontal in. direction, not 
bifurcated, and has attached to it the ligamentum nuchse. [On flexion of the head 
and neck in the living model this spine, and sometimes those of the sixth cervical 
and first dorsal, become very prominent.] The transverse process is usually of 
large size, especially its posterior root; its upper surface has usually a shallow groove, 
and it seldom presents more than a trace of bifurcation at its extremity. [Occasion- 
ally the anterior part of the transverse process is developed into a cervical rib.] The 
vertebral foramen is sometimes as large as in the other cervical vertebrae, [but is] 
usually smaller on one or both sides, and sometimes wanting. On the left side it 
occasionally gives passage to the vertebral artery; more frequently the vertebral 
vein traverses it on both sides; but the usual arrangement is for both artery and 
vein to pass through the foramen in the transverse process of the sixth cervical. 
[Occasionally the vessels do not enter the vertebral foramina till they get to the 
fifth, or even the fourth, vertebra.] 
The bodies of the dorsal vertebrae resemble those in the cervical and lumbar 
regions at the respective ends of this portion of the spine; but in the middle of the 
dorsal region their form is very characteristic, being heart-shaped and as broad in 
the antero-posterior as in the lateral direction. They are thicker behind than in 
front, flat above and below, convex and prominent in front, deeply concave behind, 
slightly constricted in front and at the sides, and marked on each side, near the root 
Characters of the Dorsal Vertebral 
Fig. 117. 
Suvorurr Artie. .Process 
Devil.facet for lead of Rib 
Facet for Tubercle of Rib 
De m if acet for hea. cZ ofJt 11 
Infer. Artic .Proc. 
A Dorsal Vertebra. 
of the pedicle, by two demi-facets, one above, the other below. These are covered 
with cartilage in the recent state, and when articulated with the adjoining vertebrae 
form, with the intervening fibro-cartilage, oval surfaces for the reception of the 
heads of the corresponding ribs. The pedicles are directed backward, and the 148 
THE SKELETON. 
inferior intervertebral notches are of large size and deeper than in any other region 
of the spine. The lamince are broad, thick, and imbricated; that is to say, over- 
lap one another like tiles on a roof. The spinal foramen is small and of a circular 
form. The articular processes are flat, nearly vertical in direction, and project 
from the upper and lower part of the pedicles, the superior being directed back- 
ward and a little outward and upward, the inferior forward and a little inward and 
Fig. 118. 
(An entire facet above 
[ADeinifaeet le/oui 
-Al) emi-facet above 
■0 tie entire facet 
, An entire facet 
Nofacet on Trans.Proc. 
which is rudimentartf 
An entire facet 
No facet onlransfir. 
Inf er. Artic. P%oe 
con ueocami turn cd 
\\ outward 
Peculiar Dorsal Vertebra. 
downward. The transverse jorocesses arise from the same parts of the arch as the 
posterior roots of the transverse processes in the neck, and are situated behind the 
articular processes and pedicles; they are thick, strong, and of great length, 
directed obliquely backward'and outward, presenting a clubbed extremity, which 
is tipped on its anterior part by a small concave surface, for articulation with the 
tubercle of a rib. Besides the articular facet for the rib, two indistinct tubercles LUMBAR VERTEBRAE. 
149 
may be seen rising from the extremity of the transverse processes, one near the 
upper, the other near the lower border. In man they are comparatively of small 
size, and serve only for the attachment of muscles. But in some animals they 
attain considerable magnitude, either for the purpose of more closely connecting the 
segments of this portion of the spine or for muscular and ligamentous attachment. 
The spinous processes are long, triangular in form (bayonet-shaped), directed obliquely 
downward, and terminate in a tubercular extremity. They overlap one another from 
the fifth to the eighth, but are less oblique in direction above and below. 
The peculiar dorsal vertebrae are the first, ninth, tenth, eleventh, and twelfth 
(Fig. 118). 
The First Dorsal Vertebra presents, on each side of the body, a single entire 
articular facet for the head of the first rib, and a half-facet for the upper half of 
the second. The upper surface of the body is like that of a cervical vertebra, being 
broad, transversely concave, and lipped on each side. The articular surfaces are 
oblique, and the spinous process thick, long, and almost horizontal. 
The Ninth Dorsal has no demi-facet below. In some subjects, however, the 
ninth has two demi-facets on each side; then the tenth has a demi-facet at the upper 
part, none below. 
The Tenth Dorsal has (except in the cases just mentioned) an entire articular 
facet on each side above, which is partly placed on the outer surface of the pedicle. 
It has no demi-facet below. 
In the Eleventh Dorsal the body approaches in its form and size to the lumbar. 
The articular facets for the heads of the ribs, one on each side, are of large size, 
and placed chiefly on the pedicles, which are thicker and stronger in this and the 
next vertebra than in any other part of the dorsal region. The transverse pro- 
cesses are very short, tubercular at their extremities, and have no articular facets 
for the tubercles of the ribs. The spinous process is short, nearly horizontal in 
direction, and presents a slight tendency to bifurcation at its extremity. 
The Twelfth Dorsal has the same general characters as the eleventh, but may 
be distinguished from it by the inferior articular processes being convex and turned 
outward, like those of the lumbar vertebrae; by the general form of the body, lami- 
nae, and spinous process, approaching to that of the lumbar vertebrae; and by the 
transverse processes being shorter, and marked by three elevations, the superior, 
inferior, and external tubercles, which correspond to the mammillary, accessory, and 
transverse processes of the lumbar vertebrae. Traces of similar elevations are usu- 
ally to be found upon the other dorsal vertebrae. (Vide antea.) 
Characters of the Lumbar Vertebrje. 
The Lumbar Vertebrae (Fig. 119) are the largest segments of the vertebral 
column. The body is large, broader from side to side than from before backward, 
slightly thicker in front than behind, flattened or slightly concave above and below, 
concave behind, and deeply constricted in front and at the sides, presenting promi- 
nent margins, which afford a broad basis for the support of the superincumbent 
weight. The pedicles are very strong, directed backward from the upper part of 
the bodies; consequently the inferior intervertebral notches are of large size. The 
laminae are short, but broad and strong, and the foramen triangular, larger than in 
the dorsal, smaller than in the cervical region. The superior articular processes 
are concave, and look almost directly inward; the inferior, convex, look outward 
and a little forward: the former are separated by a much wider interval than the 
latter, embracing the lower articulating processes of the vertebra above. The trans- 
verse processes are long, slender, directed transversely outward in the upper three 
lumbar vertebrae, slanting a little upward in the lower two. They are situated in 
front of the articular processes, instead of behind them, as in the dorsal vertebrae, 
and are by some anatomists considered homologous with the ribs. Of the two tuber- 
cles noticed in connection with the transverse processes in the dorsal region, the 
superior ones become connected in this region with the back part of the superior 150 
THE SKELETON. 
articular processes, and have received the name of mammillary processes; the infe- 
rior are represented by a small process pointing downward, situated at the back part 
of the base of the transverse process, and called the accessory processes. Although 
in man these are comparatively small, in some animals they attain considerable size, 
Fig. 119. 
Super. Artic. Proc. 
Lumbar Vertebra. 
and serve to lock the vertebrae more closely together. The spinous processes are 
thick and broad, somewhat quadrilateral, horizontal in direction, thicker below than 
above, and terminate by a rough, uneven border. 
The Fifth Lumbar Vertebra is characterized by having the body much thicker 
in front than behind, which accords with the prominence of the sacro-vertebral artic- 
ulation ; by the smaller size of its spinous process; by the wide interval between the 
inferior articulating processes; and by the greater size and thickness of its trans- 
verse processes. 
Structure of the Vertebrae.-The structure of a vertebra differs in different 
parts. The body is composed of light spongy cancellous tissue, having a thin 
coating of compact tissue on its external surface, perforated by numerous orifices, 
some of large size, for the passage of vessels; its interior is traversed by one'or two 
large canals for the reception of veins, which converge toward a single large irreg- 
ular aperture or several small apertures at the posterior part of the body of each 
bone. The arch and processes projecting from it have, on the contrary, an exceed- 
ingly thick covering of compact tissue. 
Development.-Each vertebra is formed of three primary cartilaginous portions 
(Fig. 120)-one for each lamina and its processes, and one for the body. Ossifica- 
tion commences in the laminae about the sixth week of foetal life, in the situation 
where the transverse processes afterward project, the ossific granules shooting back- 
ward to the spine, forward to the body, and outward into the transverse and articular 
processes. Ossification in the body commences in the middle of the cartilage about 
the eighth week. According to some authors, ossification commences in the laminae 
only in the upper vertebrae-i. e. in the cervical and upper dorsal. The first ossific 
point in the lower vertebrae is that which is to form the body, the osseous centres 
for the laminae appearing at a subsequent period. At birth these three pieces are 
perfectly separate. During the first year the laminae become united behind by a 
portion of cartilage in which the spinous process is ultimately formed, and thus the 
arch is completed. About the third year the body is joined to the arch on each side 
in such a manner that the body is formed from the three original centres of ossifica- 
tion, the amount contributed by the pedicles increasing in extent from below upward. 
Thus the bodies of the sacral vertebrae are formed almost entirely from the central 
nuclei; the bodies of the lumbar are formed laterally and behind by the pedicles: 
in the dorsal region the pedicles advance as far forward as the articular depressions 
for the head of the ribs, forming these cavities of reception, and in the neck the lat- LUMBAR VERTEBRAE. 
151 
eral portions of the bodies are formed entirely by the advance of the pedicles. Before 
puberty no other changes occur, excepting a gradual increase in the growth of these 
primary centres, the upper and under surfaces of the bodies and the ends of the trans- 
verse and spinous processes being tipped with cartilage, in which ossific granules are 
not as yet deposited. At sixteen years (Fig. 121) four secondary centres appear- 
one for the tip of each transverse process, and two (sometimes united into one) for the 
end of the spinous process. At twenty-one years (Fig. 122) a thin circular epiphysial 
plate of bone is formed in the layer of cartilage situated on the upper and under sur- 
By 3 primary centres 
Fig. 120. 
Bi! 3 centres 
Fig. 123. 
(- 1 for Body ( 8 f week) 
f for artter. areA f1- y ') 
i fir each 
lateraL mass} J 
Atlas. 
/ for each Lamina (f> weed J 
By Se.con,elcbrij Centre* 
Fig.121. 
Jij 0 centres 
Fig. 124. 
Zfor odoiitoidproc moj 
-Exceptional cases.- 
/for each la teral mass 
/ for body (G'f mo.) 
Axis. 
■ !for occeh 
Trans. Proc. 
7/7 y Vs. 
Fig. 125. 
2. sometimes / T for Spin .proc. 
2. aciditiimal cent re's 
Bi/ 2 additional vlates 
Fig. 122. 
1 for upper surface, 
of lady U/ 
fS 
-Ifor under surfzef. 
of body 
Development of a Vertebra. 
for tubercles on Sup .Artic.Proc 
Lumbar Vertebra. 
faces of the body, the former being the thicker of the two. All these become joined, 
and the bone is completely formed about the thirtieth year of life. 
Exceptions to this mode of development occur in the first, second, and seventh 
cervical, and in the vertebrae of the lumbar region. 
The Atlas (Fig. 123) is developed by two primary centres and by one or more 
epiphyses. The two primary centres are destined for the two lateral or neural 
masses, the ossification of which commences generally about the eighth week, near 
the articular processes, and extends backward: these portions of bone are separated 
from one another behind, at birth, by a narrow interval filled in with cartilage. 
Between the second and third years they unite, either directly or through the medium 
of an epiphysial centre developed in the cartilage near their point of junction. The 
anterior arch at birth is altogether cartilaginous, and this portion of the atlas is com- 
pleted by the gradual extension forward and ultimate junction of the two neural pro- 
cesses. Occasionally, a separate nucleus, which appears about the end of the first year 
after birth, is developed in the anterior arch, which, extending laterally, joins the neu- 
ral processes in front of the pedicles; or there are two nuclei developed in the ante- 
rior arch, one on either side of the median line, which join to form a single mass, 
afterward united to the lateral portions in front of the articulating processes. 152 
THE SKELETON. 
The Axis (Fig. 124) is developed by six centres. The body and arch of this bone 
are formed in the same manner as the corresponding parts in the other vertebrae- 
one centre for the lower part of the body and one for each lamina. The odontoid 
process consists originally of an extension upward of the cartilaginous mass in which 
the lower part of the body is formed. At about the sixth month of foetal life two 
osseous nuclei make their appearance in the base of this process: they are placed 
laterally, and join before birth to form a conical bilobecl mass deeply cleft above: 
the interval between the cleft and the summit of the process is formed by a wedge- 
shaped piece of cartilage, the base of the process being separated from the body by 
a cartilaginous interval which gradually becomes ossified, sometimes by a separate 
epiphysial nucleus. Finally, as Dr. Humphry has demonstrated, the apex of the 
odontoid process has a separate nucleus. 
The Seventh Cervical.-The anterior or costal part of the transverse process 
of the seventh cervical is developed from a separate osseous centre at about the sixth 
month of foetal life, and joins the body and posterior division of the transverse pro- 
cess between the fifth and sixth years. Sometimes this process continues as a sepa- 
rate piece, and, becoming lengthened outward, constitutes what is known as a cer- 
vical rib. 
The Lumbar Vertebrae (Fig. 125) have two additional centres (besides those 
peculiar to the vertebrae generally) for the mammillary tubercles, which project from 
the back part of the superior articular processes. The transverse process of the first 
lumbar is sometimes developed as a separate piece, which may remain permanently 
unconnected with the remaining portion of the bone, thus forming a lumbar rib-a 
peculiarity which is rarely met with. 
Progress of Ossification of the Spine generally.-Ossification of the laminae 
of the vertebrae commences at the upper part of the spine, and proceeds gradually 
downward; hence the frequent occurrence of spina bifida in the lower par,t of the 
spinal column [from non-union posteriorly of the two centres for the laminae]. Ossi- 
fication of the bodies, on the other hand, commences a little below the centre of the 
spinal column (about the ninth or tenth dorsal vertebra), and extends both upward 
and downward. Although, however, the ossific nuclei make their first appearance 
in the lower dorsal vertebrae, the lumbar and first sacral are those in which these 
nuclei are largest at birth. 
Attachment of Muscles.-To the Atlas are attached nine pairs: the Longus 
colli, Rectus anticus minor, Rectus lateralis, Rectus posticus minor, Obliquus supe- 
rior and inferior, Splenius colli, Levator anguli scapulae, and First Intertransverse. 
To the Axis are attached eleven pairs: the Longus colli, Obliquus inferior, Rec- 
tus posticus major, Semispinalis colli, Multifidus spinae, Levator anguli scapulae, 
Splenius colli, Scalenus medius, Transversalis colli, Intertransversales, Interspinales. 
To the remaining vertebrae generally are attached thirty-five pairs and a single 
muscle: anteriorly, the Rectus anticus major, Longus colli, Scalenus anticus, medius, 
and posticus, Psoas magnus, Psoas parvus, Quadratus lumborum, Diaphragm, 
Obliquus internus, and Transversalis; posteriorly, the Trapezius, Latissimus dorsi, 
Levator anguli scapulae, Rhomboideus major and minor, Serratus posticus superior 
and inferior, Splenius, Erector spinae, Sacro-lumbalis, Longissimus dorsi, Spinalis 
dorsi, Cervicalis ascendens, Transversalis colli, Trachelo-mastoid, Complexus, Biven- 
ter cervicis, Semispinalis dorsi and colli, Multifidus spinae, Rotatores spinae, Inter- 
spinales, Supraspinales, Intertransversales, Levatores costarum. 
Sacral and Coccygeal Vertebra. 
The Sacral and Cocdygeal Vertebrae consist, at an early period of life, of nine 
separate pieces, which are united in the adult so as to form two bones, five entering 
into the formation of the sacrum, four into that of the coccyx. Occasionally the 
coccyx consists of five bones.1 
The Sacrum (sacrus, sacred) is a large triangular bone (Fig. 126) situated at 
1 Dr. Humphry describes this as the usual composition of the coccyx (On the Skeleton, p. 456). SACRAL AND COCCYGEAL VERTEBRAE. 
153 
the lower part of the vertebral column and at the upper and back part of the pelvic 
cavity, where it is inserted like a wedge between the two innominate bones, its upper 
part, or base, articulating with the last lumbar vertebra, its apex with the coccyx. 
The sacrum is curved upon itself, and placed very obliquely, its upper extremity pro- 
jecting forward, and forming, with the last lumbar vertebra, a very prominent angle 
called the promontory or sacro-vertebral angle, whilst its central part is directed back- 
ward, so as to give increased capacity to the pelvic cavity. It presents for examina- 
Fig. 126. 
Promontory 
Sacrum, anterior surface. 
tion an anterior and posterior surface, two lateral surfaces, a base, an apex, and a 
central canal. 
The anterior surface is concave from above downward, and slightly so from side 
to side. In the middle are seen four transverse ridges, indicating the original 
division of the bone into five separate pieces. The portions of bone intervening 
between the ridges correspond to the bodies of the vertebrae. The body of the first 
segment is of large size, and in form resembles that of a lumbar vertebra; the suc- 
ceeding ones diminish in size from above downward, are flattened from before back- 
ward, and are curved so as to accommodate themselves to the form of the sacrum, 
being concave in front, convex behind. At each end of the ridges above mentioned 
are seen the anterior sacral foramina, analogous to the intervertebral foramina, four 
in number on each side, somewhat rounded in form, diminishing in size from above 
downward, and directed outward and forward; they transmit the anterior branches 
of the sacral nerves. External to these foramina is the lateral mass, consisting, at 
an early period of life, of separate segments; these become blended in the adult 
with the bodies, with each other, and with the posterior transverse processes. Each 
lateral mass is traversed by four broad shallow grooves which lodge the anterior sacral 154 
THE SKELETON. 
nerves as they pass outward, the grooves being separated by prominent ridges of bone 
which give attachment to the slips of the Pyriformis muscle. 
If a vertical section is made through the centre of the bone (Fig-127), the bodies 
are seen to be united at their circumference 
by bone, a wide interval being left centrally, 
which, in the recent state, is filled by inter- 
vertebral substance. In some bones this 
union is more complete between the lower 
segments than between the upper ones. 
The posterior surface (Fig. 128) is 
convex, and much narrower than the an- 
terior. In the middle line are three or 
four tubercles, which represent the rudi- 
mentary spinous processes of the sacral 
vertebrae. Of these tubercles, the first is 
usually prominent and perfectly distinct 
from the rest; the second and third are 
either separate or united into a tubercular 
ridge, which diminishes in size from above 
downward ; the fourth usually, and the fifth 
always, remaining undeveloped. Externa] 
to the spinous processes on each side are 
the lamince, broad and well marked in the 
first three pieces, sometimes the fourth, and 
generally the fifth, being undeveloped; in 
this situation the lower end of the sacral 
canal is exposed. [In severe bed-sores this 
canal is sometimes opened here by slough- 
ing, and may be followed by spinal men- 
ingitis, etc.] External to the laminae is a 
linear series of indistinct tubercles repre- 
senting the articular processes ; the upper 
pair are large, well-developed, and corre- 
spond in shape and direction to the superior 
articulating processes of a lumbar vertebra; 
the second and third are small; the fourth 
and fifth (usually blended together) are 
situated on each side of the sacral canal: they are called the sacral cornua, and 
articulate with the cornua of the coccyx. External to the articular processes are 
the four posterior sacral foramina; they are smaller in size and less regular in 
form than the anterior, and transmit the posterior branches of the sacral nerves. 
On the outer side of the posterior sacral foramina is a series of tubercles, the 
rudimentary transverse processes of the sacral vertebrae. The first pair of trans- 
verse tubercles are of large size, very distinct, and correspond with each superior 
angle of the bone; the second, small in size, enter into the formation of the sacro- 
iliac articulation; the third give attachment to the oblique fasciculi of the posterior 
sacro-iliac ligaments, and the fourth and fifth to the great sacro-sciatic ligaments. 
The interspace between the spinous and transverse processes on the back of the 
sacrum presents a wide shallow concavity called the sacral groove: it is continuous 
above with the vertebral groove, and lodges the origin of the Erector spinae. 
The lateral surface, broad above, becomes narrowed into a thin edge below. 
Its upper half presents in front a broad ear-shaped surface for articulation with the 
ilium. This is called the auricular surface, and in the fresh state is coated with 
fibro-cartilage. It is bounded posteriorly by deep and uneven impressions, for the 
attachment of the posterior sacro-iliac ligaments. The lower half is thin and sharp, 
and gives attachment to the greater and lesser sacro-sciatic ligaments, and to some 
fibres of the Gluteus maximus; below, it presents a deep notch, which is converted 
Fig. 127. 
Vertical Section of the Sacrum. SA CDAL AND COCCYGEAL VERTEBRA. 
155 
into a foramen by articulation with the transverse process of the upper piece of the 
coccyx, and transmits the anterior branch of the fifth sacral nerve. 
The base of the sacrum, which is broad and expanded, is directed upward and 
forward. In the middle is seen an oval articular surface which corresponds with 
the under surface of the body of the last lumbar vertebra, bounded behind by the 
large triangular orifice of the sacral canal. This orifice is formed behind by the 
spinous process and laminae of the first sacral vertebra, whilst projecting from it 
on each side are the superior articular processes: they are oval, concave, directed 
backward and inward, like the superior articular processes of a lumbar vertebra; 
and in front of each articular process is an intervertebral notch which forms the 
lower half of the last intervertebral foramen. Lastly, on each side of the oval 
articular surface is a broad and flat triangular surface of bone which extends out- 
Fig. 128. 
sUjijier i of 
post sacralfir. 
Sacrum, posterior surface. 
ward, supports the Psoas magnus muscle and lumbo-sacral cord, and is continuous 
on each side with the iliac fossa. This is called the ala of the sacrum, and gives 
attachment to a few of the fibres of the Iliacus muscle. 
The apex, directed downward and forward, presents a small oval concave surface 
for articulation with the coccyx. 
lhe Sacral [i. e. Spinal] Canal runs throughout the greater part ef the bone; 
it is large and triangular in form above, small and flattened from before; backward 
below. In this situation its posterior wall is incomplete, from the non-development 
of the lamime and spinous processes. It lodges the sacral nerves, and is perforated 
by the anterior and posterior sacral foramina, through which these pass out. 
Structure.-It consists of much loose, spongy tissue within, invested externally 
by a thin layer of compact tissue. 
Differences in the Sacrum of the Male and Female.-The sacrum in the 156 
THE SKELETON. 
female is usually wider than in the male', and it is much less curved, the upper half 
of the bone being nearly straight, the lower half presenting the greatest amount of 
curvature. The bone is also directed more obliquely backward, which increases the 
size of the pelvic cavity and forms a more prominent sacro-vertebral angle. In the 
male the curvature is more evenly distributed over the whole length of the bone, 
and is altogether greater than in the female. 
Peculiarities of the Sacrum.-This bone, in some cases, consists of six pieces ; 
occasionally, the number is reduced to four. Sometimes the bodies of the first and 
second segments are not joined, or the 
laminae and spinous processes have not 
coalesced. Occasionally, the upper pair 
of transverse tubercles are not joined to 
the rest of the bone on one or both sides; 
and lastly, the sacral canal may be open 
for nearly the lower half of the bone, in 
consequence of the imperfect development 
of the laminae and spinous processes. The 
sacrum also varies considerably with re- 
spect to its degree of curvature. From 
the examination of a large number of 
skeletons it would appear that in one 
set of cases the anterior surface of this 
bone was nearly straight, the curvature, 
which was very slight, affecting only its 
lower end. In another set of cases the 
bone was curved throughout its whole 
length, but especially toward its middle. 
In a third set the degree of curvature 
was less marked, and affected especially 
the lower third of the bone. 
Development (Fig. 129).-The sac- 
rum, formed by the union of five verte- 
brae, has thirty-five centres of ossification. 
The bodies of the sacral vertebrae have 
each three ossific centres-one for the 
central part, and one for the epiphysial 
plates on its upper and under surface. 
The arch of each sacral vertebra is 
developed by two centres, one for each 
lamina. These unite with each other 
behind, and subsequently join the body. 
The lateral masses have six additional 
centres, two for each of the first three 
vertebrae. These centres make their ap- 
pearance above and to the outer side of 
the anterior sacral foramina (Fig. 129), and 
are developed into separate segments (Fig. 
130); they are subsequently blended with 
each other and with the bodies and trans- 
verse processes to form the lateral mass. 
Lastly, each lateral surface of the 
sacrum is developed by two epiphysial 
plates (Fig. 131)-one for the auricular surface, and one for the remaining part of 
the thin lateral edge of the bone. 
Period of Development.-At about the eighth or ninth week of foetal life ossi- 
fication of the central part of the bodies of the first three vertebrae commences, and 
at a somewhat later period that of the last two. Between the sixth and eighth 
A-HLitional centres 
Fig. 129. 
for the first 3pieces * 
at berth 
Fig. 130. 
At 41 years. 
Fin. 131. 
2 Epiphysal larnince 
for each lateral sarfa.ce. 
at 25 Q y - 
Figs. 129-131, Development of Sacrum. THE COCCYX. 
157 
months ossification of the laminae takes place, and at about the same period the cha- 
racteristic osseous tubercles for the first three sacral vertebrae make their appearance. 
The period at which the arch becomes completed by the junction of the laminae with 
the bodies in front and with each other behind varies in different segments. The 
junction takes place first in the lowermost vertebrae as early as the second year, but 
is not effected in the uppermost until the fifth or sixth year. About the sixteenth 
year the epiphyses for the upper and under surfaces of the bodies are formed, and 
between the eighteenth and twentieth years those for each lateral surface of the 
sacrum make their appearance. The bodies of the sacral vertebrae are, during early 
life, separated from each other by intervertebral disks. But about the eighteenth 
year the two lowest segments become joined together by ossification extending 
through the disk. This process gradually extends upward until all the segments 
become united, and the bone is completely formed from the twenty-fifth to the thir- 
tieth year of life. 
Articulations.-With four bones-the last lumbar vertebra, coccyx, and the two 
ossa innominata. 
Attachment of Muscles.-To eight pairs: in front, the Pyriformis and Coc- 
cygeus, and a portion of the Iliacus to the base of the bone; behind, the Gluteus 
maximus, Latissimus dorsi, Multifidus spinoe and Erector spinae, and sometimes the 
Extensor coccygis. 
The Coccyx (xoxxuf, cuckoo), so called from having been compared to a cuckoo's 
beak (Fig. 132), is usually formed of four small segments of bone, the most rudi- 
mentary parts of the vertebral column. In each of the first three segments may be 
traced a rudimentary body, articular and transverse pro- 
cesses : the last piece (sometimes the third) is a mere 
nodule of bone, without distinct processes. All the seg- 
ments are destitute of laminae and spinous processes, and 
consequently of spinal canal and intervertebral foramina. 
The first segment is the largest; it resembles the lower- 
most sacral vertebra, and often exists as a separate piece: 
the last three, diminishing in size from above downward, 
are usually blended together so as to form a single bone. 
The gradual diminution in the size of the pieces gives 
this bone a triangular form, the base of the triangle join- 
ing the end of the sacrum. It presents for examination 
an anterior and a posterior surface, two borders, a base, and 
an apex. The anterior surface is slightly concave, and 
marked with three transverse grooves, indicating the 
points of junction of the different pieces. It has at- 
tached to it the anterior sacro-coccygeal ligament and 
Levator ani muscle, and supports the lower end of the 
rectum. The posterior surface is convex, marked by 
transverse grooves similar to those on the anterior sur- 
face, and presents on each side a lineal row of tubercles, 
the rudimentary articular processes of the coccygeal ver- 
tebrae. Of these, the superior pair are very large, and 
are called the cornua of the coccyx: they project up- 
ward and articulate with the cornua of the sacrum, the 
junction between these two bones completing the fifth 
posterior sacral foramen for the transmission of the pos- 
terior branch of the fifth sacral nerve. The lateral bor- 
ders are thin, and present a series of small eminences 
which represent the transverse processes of the coccygeal 
vertebrae. Of these, the first on each side is of large size, flattened from before 
backward, and often ascends to join the lower part of the thin lateral edge of the 
The Coccyx. 
Fig. 132. 
Cornua 
/ ' 
Tra nr. 
prac. 
./Interior jS'U,rfa,ee 
-Posterior 
Coccyx. 158 
THE SKELETON. 
Fig. 133. 
1st Cervi- 
cal, or 
Atlas. 
2d Cervi- 
cal, or 
Axis. 
sacrum, thus completing the fifth anterior sacral 
foramen for the transmission of the anterior divis- 
ion of the fifth sacral nerve; the others diminish 
in size from above downward, and are often want- 
ing. The borders of the coccyx are narrow, and 
give attachment on each side to the sacro-sciatic 
ligaments and Coccygeus muscle. The base pre- 
sents an oval surface for articulation with the sac- 
rum. The apex is rounded, and has attached to it 
the tendon of the external Sphincter muscle. It 
is occasionally bifid, and sometimes deflected to one 
or the other side. 
Development.-The coccyx is developed by 
four centres, one for each piece. Occasionally, 
one of the first three pieces of this bone is devel- 
oped by two centres placed side by side. The os- 
sific nuclei make their appearance in the following 
order: in the first segment, at birth ; in the second 
piece, at from five to ten years ; in the third, from 
ten to fifteen years; in the fourth, from fifteen to 
twenty years. As age advances these various seg- 
ments become united in the following order: the 
first two pieces join; then the third and fourth; 
and lastly, the bone is completed by the union of 
the second and third. At a late period of life, 
especially in females, the coccyx often becomes 
joined to the end of the sacrum. 
Articulation.-With the sacrum. 
Attachment of Muscles.-To four pairs and 
one single muscle : on either side, the Coccygeus ; 
behind, the Gluteus maximus and Extensor coc- 
cygis when present; at the apex, the Sphincter 
ani; and in front, the Levator ani. 
Is* Dorsal. 
Of the Spine in General. 
The Spinal Column, formed by the junction 
of the vertebrae, is situated in the median line at 
the posterior part of the trunk: its average length 
is about two feet two or three inches, measured 
along the curved anterior surface of the column. 
Of this length, the cervical part measures about 
five, the dorsal about eleven, the lumbar about 
seven inches, and the sacrum and coccyx the re- 
mainder. 
Viewed in front, it presents two pyramids 
joined together at their bases, the upper one 
being formed by all the vertebrae from the second 
cervical to the last lumbar; the lower one, by the 
sacrum and coccyx. When examined more close- 
ly the upper pyramid is seen to be formed of three 
smaller pyramids. The uppermost of these con- 
sists of the six lower cervical vertebrae, its apex 
being formed by the axis or second cervical, its 
base by the first dorsal. The second pyramid, 
which is inverted, is formed by the foui' upper 
dorsal vertebrae, the base being at the first dorsal, 
the smaller end at the fourth. The third pyr- 
I*.6 Lu mb a 
Lateral View of the Spine. THE SPINE IN GENERAL. 
159 
amid commences at the fourth dorsal, and gradually increases in size to the fifth 
lumbar. 
Viewed laterally (Fig. 133), the spinal column presents several curves, which cor- 
respond to the different regions of the column, and are called cervical, dorsal, lumbar, 
and pelvic. The cervical curve commences at the apex of the odontoid process, and 
terminates at the middle of the second dorsal vertebra; it is convex in front, and is 
the least marked of all the curves. The dorsal curve, which is concave forward, com- 
mences at the middle of the second, and terminates at the middle of the twelfth dorsal. 
Its most prominent point behind corresponds to the body of the seventh or eighth 
vertebra. The lumbar curve commences at the middle of the last dorsal vertebra, 
and terminates at the sacro-vertebral angle. It is convex anteriorly, the convexity 
of the lower three vertebrae being much greater than that of the upper ones. The 
pelvic curve commences at the sacro-vertebral articulation, and terminates at the 
point of the coccyx. It is concave anteriorly. These curves are partly due to the 
shape of the bodies of the vertebrae, and partly to the intervertebral substances, as 
will be explained in the Articulations of the Spine.1 
The spine has also a slight lateral curvature, the convexity of which is directed 
toward the right side. This is most probably produced, as Bichat first explained, 
chiefly by muscular action, most persons using the right arm in preference to the 
left, especially in making long-continued efforts, when the body is curved to the 
right side. In support of this explanation it has been found by Beclard that in 
one oi' two individuals who were left-handed the lateral curvature was directed to 
the left side. 
The spinal column presents for examination an anterior, a posterior, and two 
lateral surfaces, a base, summit, and vertebral canal. 
The anterior surface presents the bodies of the vertebrae separated in the recent 
state by the intervertebral disks. The bodies are broad in the cervical region, nar- 
row in the upper part of the dorsal, and broadest in the lumbar region. The whole 
of this surface is convex transversely, concave from above downward in the dorsal 
region, and convex in the same direction in the cervical and lumbar regions. 
The posterior surface presents in the median line the spinous processes. These 
are short, horizontal, with bifid extremities in the cervical region. In the dorsal 
region they are directed obliquely above, assume almost a vertical direction in the 
middle, and are horizontal below, as are also the spines of the lumbar vertebrae. 
They are separated by considerable intervals in the loins, by narrower intervals in 
the neck, and are closely approximated in the middle of the dorsal region. Occa- 
sionally, one of these processes deviates a little from the' median line-a fact to be 
remembered in practice, as irregularities of this sort are attendant also on fractures 
or displacements of the spine. [The study of the vertebral spines and of the groove 
between the lateral muscular masses is of great importance. If the model be made 
to flex and extend the trunk, and to make rotation and lateral flexion, the greatest 
possible variations are seen, especially on comparing the various regions of the 
spine.] On either side of the spinous processes, extending the whole length of the 
column, is the vertebral groove, formed by the laminae in the cervical and lumbar 
regions, where it is shallow, and by the laminae and transverse processes in the 
dorsal region, where it is deep and broad. In the recent state these grooves lodge 
the deep muscles of the back. External to the vertebral grooves are the articular 
processes, and still more externally the transverse processes. In the dorsal region 
the latter processes stand backward, on a plane considerably posterior to the same 
processes in the cervical and lumbar regions. In the cervical region the transverse 
processes are placed in front of the articular processes and between the intervertebral 
foramina. In the lumbar they are placed also in front of the articular processes, but 
behind the intervertebral foramina. In the dorsal region they are posterior both to 
the articular processes and foramina. 
The lateral surfaces are separated from the posterior by the articular processes 
1 Professor Humphry gives the measurement of these curves in an adult female. (See The 
Human Skeleton, p. 147.) 160 
THE SKELETON. 
in the cervical and lumbar regions, and by the transverse processes in the dorsal. 
These surfaces present in front the sides of the bodies of the vertebrae, marked in 
the dorsal region by the facets for articulation with the heads of the ribs. More 
posteriorly are the intervertebral foramina, formed by the juxtaposition of the inter- 
vertebral notches, oval in shape, smallest in the cervical and upper part of the dorsal 
regions, and gradually increasing in size to the last lumbar. They are situated 
between the transverse processes in the neck, and in front of them in the back and 
loins, and transmit the spinal nerves. The base of the vertebral column [z. e. of the 
twenty-four movable vertebrae] is formed by the under surface of the body of the 
fifth lumbar vertebra, and the summit by the upper surface of the atlas. The 
vertebral oi* spinal canal follows the different curves of the spine: it is largest in 
those regions in which the spine enjoys the greatest freedom of movement, as in the 
neck and loins, where it is wide and triangular, and narrow and rounded in the 
back, where motion is more limited. 
THE SKULL. 
The Skull, or superior expansion of the vertebral column, has been described as 
if composed of four vertebrae, the elementary parts of which are specially modified 
in form and size, and almost immovably connected, for the reception of the brain 
and special organs of the senses. These vertebrae are the occipital, parietal, frontal, 
and nasal. Descriptive anatomists, however, divide the skull into two parts-the 
Cranium and the Face. The Cranium (xjoawoy, the skull) is composed of eight 
bones-viz. the occipital, two parietal, frontal, two temporal, sphenoid, and ethmoid. 
The Face is composed of fourteen bones-viz. the two nasal, two superior maxillary, 
two lachrymal, two malar, two palate, two inferior turbinated, vomer, and inferior 
maxillary. The ossicula auditus, the teeth, and IFrrmian bones are not included in 
this enumeration. 
Occipital. 
Two Parietal. 
Frontal. 
Two Temporal. 
Sphenoid. 
Ethmoid. 
Two Nasal. 
Two Superior Maxillary. 
Two Lachrymal. 
Two Malar. 
Two Palate. 
Two Inferior Turbinated. 
Vomer. 
Inferior Maxillary. 
Cranium, 8 bones: 
Skull, 22 bones. 
Face, IJj. bones: 
The Occipital Bone. 
The Occipital Bone (06, caput, against the head) is situated at the back part 
and base of the cranium, is trapezoid in form (Fig. 134), curved upon itself, and 
presents for examination two surfaces, four borders, and four angles. 
The external surface is convex. Midway between the summit of the bone and 
the posterior margin of the foramen magnum is a prominent tubercle, the external 
occipital protuberance, for the attachment of the Ligamentum nuchas ; and, descend- 
ing from it as far as the foramen, a vertical ridge, the external occipital crest. This 
tubercle and crest vary in prominence in different skulls. Passing outward from the 
occipital protuberance is a semicircular ridge on each side, the superior curved line, 
and running parallel with these from the middle of the crest are two other ridges, 
the inferior curved lines. The surface of the bone above the superior curved lines TFTE OCCIPITAL BONE. 
161 
is rough, and in the recent state is covered by the Occipito-frontalis muscle, whilst 
the ridges, as well as the surface of the bone between them, serve for the attachment 
of numerous muscles. The superior curved line gives attachment internally to the 
Trapezius, externally to the muscular origin of the Occipito-frontalis and to the 
Sterno-cleido-mastoid, to the extent shown in Fig. 134, the depressions between the 
Fig. 134. 
SUPERIOR 
CONSTRICTOR 
-ofEharynv 
Occipital Bone, outer surface. 
curved lines to the Complexus internally, the Splenius capitis and Obliquus capitis 
superior externally. The inferior curved line and the depressions below it afford 
insertion to the Rectus capitis posticus, major and minor. The surface of bone above 
the superior curved line is rough and porous, and is covered by the aponeurosis of 
the Occipito-frontalis. 
The Foramen Magnum is a large oval aperture, its long diameter extending 
from before backward. It transmits the medulla oblongata and its membranes, the 
spinal accessory nerves, and the vertebral arteries. Its back part is wide for the 
transmission of the medulla, and the corresponding margin rough for the attach- 
ment of the dura mater enclosing it; the fore part is narrower, being encroached 
upon by the condyles; it has projecting toward it from below the odontoid process, 
and its margins are smooth and bevelled internally to support the medulla oblongata. 
On each side of the foramen magnum are the condyles, for articulation with the atlas : 
they are convex, oblong, or reniform in shape, and directed downward and outward; 
they converge in front, and encroach slightly upon the anterior segment of the for- 
amen. On the inner border of each condyle is a rough tubercle for the attachment 
of the ligaments (check') which connect this bone with the odontoid process of the 
axis, whilst external to them is a rough tubercular prominence, the transverse or 
jugular process (the representative of the transverse process of a vertebra), chan- 
nelled in front by a deep notch, which forms part of the jugular foramen or foramen 162 
THE SKELETON. 
lacerum posterius. The under surface of this process affords attachment to the 
Rectus capitis lateralis; its upper or cerebral surface presents a deep groove which 
lodges part of the lateral sinus, whilst its external surface is marked by a quadrilat- 
eral rough facet, covered with cartilage in the fresh state, and articulating with a 
similar surface on the petrous portion of the temporal bone. On the outer side of 
each condyle, near its fore part, is a foramen, the anterior condyloid: it is directed 
downward, outward, and forward, and transmits the hypoglossal nerve, and occa- 
sionally a meningeal branch of the ascending pharyngeal artery. This foramen is 
sometimes double. Behind each condyle is a fossa,1 sometimes perforated at the 
bottom by a foramen, the posterior condyloid, for the transmission of a vein to the 
lateral sinus. In front of the foramen magnum is a strong quadrilateral plate of 
bone, the basilar process, wider behind than in front, its under surface, which is 
rough, presenting in the median line a tubercular ridge, the pharyngeal spine, for 
the attachment of the tendinous raphd and Superior constrictor of the pharynx, 
Sa/ierior Angle 
Fig. 135. 
Life rior jin alp 
Occipital Bone, inner surface. 
and on each side of it rough depressions for the attachment of the Rectus capitis 
anticus, major and minor. 
The internal or cerebral surface (Fig- 135) is deeply concave. The posterior 
or occipital part is divided by a crucial ridge into four fossse. The two superior 
1 This fossa presents many variations in size. It is usually shallow and the foramen small, occa- 
sionally wanting on one or both sides. Sometimes both fossa and foramen are large, but confined to 
one side only; more rarely, the foramen and fossa are very large on both sides. THE OCCIPITAL BONE. 
163 
fossae receive the posterior lobes of the cerebrum, and present slight eminences and 
depressions corresponding to their convolutions. The two inferior, which receive 
the hemispheres of the cerebellum, are larger than the former and comparatively 
smooth; both are marked by slight grooves for the lodgment of arteries. At the 
point of meeting of the four divisions of the crucial ridge is an eminence, the inter- 
nal occipital protuberance. It nearly corresponds to that on the outer surface, and 
is perforated by one or more large vascular foramina. From this eminence the 
superior division of the crucial ridge runs upward to the superior angle of the bone; 
it presents a deep groove for the superior longitudinal sinus, the margins of which 
give attachment to the falx cerebri. The inferior division, the internal occipital 
crest, runs to the posterior margin of the foramen magnum, on the edge of which it 
becomes gradually lost; this ridge, which is bifurcated below, serves for the attach- 
ment of the falx cerebelli. It is usually marked by a single groove, which com- 
mences at the back part of the foramen magnum and lodges the occipital sinus. 
Occasionally the groove is double where two sinuses exist. The transverse grooves 
pass outward to the lateral angles; they are deeply channelled, for the lodgment of 
the lateral sinuses, their prominent margins affording attachment to the tentorium 
cerebelli.1 At the point of meeting of these grooves is a depression, the torcular 
Herophili2 placed a little to one or the other side of the internal occipital protuber- 
ance. More anteriorly is the foramen magnum, and on each side of it, but nearer 
its anterior than its posterior part, the internal openings of the anterior condyloid 
foramina; the internal openings of the posterior condyloid foramina are a little 
external and posterior to them, protected by a small arch of bone. At this part of 
the internal surface there is a very deep groove, in which the posterior condyloid 
foramen, when it exists, has its termination. This groove is continuous in the com- 
plete skull with the transverse groove on the posterior part of the bone, and lodges 
the end of the same sinus, the lateral. In front of the foramen magnum is the 
basilar process, presenting a shallow depression, the basilar groove, which slopes 
from behind upward and forward, and supports the medulla oblongata and part of 
the pons Varolii, and on each side of the basilar process is a narrow channel which, 
when united with a similar channel on the petrous portion of the temporal bone, 
forms a groove which lodges the inferior petrosal sinus. 
Angles.-The superior angle is received into the interval between the posterior 
superior angles of the two parietal bones: it corresponds with that part of the 
skull in the foetus which is called the posterior fontanelle. The inferior angle is 
represented by the square-shaped surface of the basilar process. At an early 
period of life a layer of cartilage separates this part of the bone from the sphenoid, 
but in the adult the union between them is osseous. The lateral angles correspond 
to the outer ends of the transverse grooves, and are received into the interval 
between the posterior inferior angles of the parietal and the mastoid portion of the 
temporal. 
Borders.-The superior extends on each side from the superior to the lateral 
angle, is deeply serrated for articulation with the parietal bone, and forms, by this 
union, the lambdoid suture. The inferior border extends from the lateral to the 
inferior angle; its upper half is rough, and articulates with the mastoid portion 
of the temporal, forming the masto-occipital suture; the inferior half articulates 
with the petrous portion of the temporal, forming the petro-occipital suture; these 
two portions are separated from each other by the jugular process. In front of 
this process is a deep notch, which, with a similar one on the petrous portion of th© 
temporal, forms the foramen lacerum posterius, or jugular foramen. This notch 
is occasionally subdivided into two parts by a small process of bone, and it generally 
1 Usually one of the transverse grooves is deeper and broader than the other ; occasionally, both 
grooves are of equal depth and breadth, or both equally indistinct. The broader of the two trans- 
verse grooves is nearly always continuous with the vertical groove for the superior longitudinal sinus, 
and occupies the corresponding side of the median line. 
2 The columns of blood coming in different directions were supposed to be pressed together at this 
point (torcular, a wine-press). [Herophilus, after whom this depression is named, and Erasistratus 
were the two earliest anatomists. They flourished about 300 years b. o } 164 
THE SKELETON. 
presents an aperture at its upper part, the internal opening of the posterior condy- 
loid foramen. 
Structure.-The occipital bone consists of two compact laminae, called the outer 
and inner tables, having between them the diploic tissue: this bone is especially 
thick at the ridges, protuberances, condyles, and internal part of the basilar process, 
whilst at the bottom of the fossae, especially the inferior, it is thin, semi-transparent, 
and destitute of diploe. 
Development (Fig. 136).-At birth the bone consists of four distinct parts: a 
tabular or expanded portion, which lies behind the foramen magnum; two condylar 
parts, which form the sides of the foramen; and a basilar part, which lies in front 
of the foramen. The number 
of nuclei for the tabular part 
vary. As a rule, there are four, 
but there may be only one (Blan- 
din) or as many as eight (Meck- 
el). They appear about the 
eighth week of foetal life, and 
soon unite to form a single piece, 
which is, however, fissured in 
the direction indicated in the 
plate. This portion of the bone 
is developed from membrane. 
The basilar and two condyloid 
portions are each developed from 
a single nucleus, appearing a lit- 
tle later and formed in cartilage. 
At about the fourth year the occipital and the two condyloid pieces join, and at 
about the sixth year the bone consists of a single piece. At a later period, between 
the eighteenth and twenty-fifth years, the occipital and sphenoid become united, 
forming a single bone. 
Articulations.-With six bones-two parietal, two temporal, sphenoid, and atlas. 
Attachment of Muscles.-To twelve pairs: to the superior curved line are 
attached the Occipito-frontalis, Trapezius, and Sterno-cleido-mastoid; to the space 
between the curved lines, the Complexus,1 Splenius capitis, and Obliquus superior; 
to the inferior curved line and the space between it and the foramen magnum, the 
Rectus capitis posticus, major and minor; to the transverse process, the Rectus lat- 
eralis; and to the basilar process, the Rectus capitis anticus, major and minor, and 
Superior Constrictor of the pharynx. 
Fig. 136. 
£ for occipital 
portion 
Join Join6.6yH. 
ai 'bi/rlJi 
tho 
■reparate. 
1 for catch condyloid 
portion 
1 for I a,sila,T portion 
Development of Occipital Bone, by seven centres. 
The Parietal Bones. 
The Parietal Bones {paries, a wall) form by their union the sides and roof of 
the skull. Each bone is of an irregular quadrilateral form, and presents for exam- 
ination two surfaces, four borders, and four angles. 
Surfaces.-The external surface (Fig. 137) is convex, smooth, and marked about 
its centre by an eminence, called the parietal eminence, which indicates the point 
where ossification commenced. Crossing the middle of the bone in an arched direc- 
tion is a curved ridge, the temporal ridge, for the attachment of the temporal fascia.2 
[About two-fifths of an inch below this ridge, at its middle, is a second less well- 
marked ridge marking the upper ridge of the Temporal muscle. See p. 684, and 
Fig. 464, p. 685.] Above this ridge the surface of the bone is rough and porous 
and covered by the aponeurosis of the Occipito-frontalis ; below it the bone is smooth, 
forms part of the temporal fossa, and affords attachment to the Temporal muscle. 
At the back part of the superior border, close to the sagittal suture, is a small 
foramen, the parietal foramen, which transmits a vein to the superior longitudinal 
sinus, and sometimes a small branch of the occipital artery. Its existence is not 
constant and its size varies considerably. 
1 To these the Biventer cervicis should be added if it is regarded as a separate muscle. 
[2 About two-fifths of an inch below this ridge, at its middle, is a second less well-marked ridge, 
marking the upper edge of the temporal muscle. See p. 684, and Fig. 564, p. 685.] THE PARIETAL BONE. 
165 
The internal surface (Fig. 138), concave, presents eminences and depressions for 
lodging the convolutions of the cerebrum and numerous furrows for the ramifications 
of the meningeal arteries; the latter run upward and backward from the anterior 
inferior angle and from the central and posterior part of the lower border of the 
bone. Along the upper margin is part of a shallow groove which, when joined to 
the opposite parietal, forms a channel for the superior longitudinal sinus, the elevated 
edges of which afford attachment to the falx cerebri. Near the groove are seen 
several depressions, especially in the skulls of old persons; they lodge the Pacchi- 
Fig. 137. 
Articulates 
with 
brontul B. 
-A'l'ticula/iej 
unth, 
Occipital B. 
Left Parietal Bone, external surface. 
onian bodies. The internal opening of the parietal foramen is also seen when that 
aperture exists. 
Borders.-The superior, the longest and thickest, is dentated to articulate with 
its fellow of the opposite side, forming the sagittal suture. The inferior is divided 
into three parts: of these, the anterior is thin and pointed, bevelled at the expense 
of the outer surface, and overlapped by the tip of the great wing of the sphenoid: 
the middle portion is arched, bevelled at the expense of the outer surface, and over- 
lapped by the squamous portion of the temporal; the posterior portion is thick, and 
serrated for articulation with the mastoid portion of the temporal. The anterior 
border, deeply serrated, is bevelled at the expense of the outer surface above and of 
the inner below; it articulates with the frontal bone, forming the coronal suture. 
The posterior border, deeply denticulated, articulates with the occipital, forming the 
lambdoid suture. 
Angles.-The anterior superior, thin and pointed, corresponds with that portion 
of the skull which in the foetus is membranous and is called the anterior fontanelle. 
The anterior inferior angle is thin and lengthened, being received in the interval 
between the great wing of the sphenoid and the frontal. This point will be found 166 
THE SKELETON. 
about one inch behind the upper and outer angle of the orbit. Its inner surface is 
marked by a deep groove, sometimes a canal, for the anterior branch of the middle 
meningeal artery. The posterior superior angle corresponds with the junction of 
the sagittal and lambdoid sutures. In the foetus this part of the skull is mem- 
branous and is called the posterior fontanelle. The posterior inferior angle articu- 
Fig. 138. 
Pdst.Shtp- 
Anglo 
Ant- Sup. 
Angle- 
Poxl.Infer. Aug 
Ant. Infer.&ncilt 
Left Parietal Bone, internal surface. 
lates with the mastoid portion of the temporal bone, and generally presents on its 
inner surface a broad shallow groove for lodging part of the lateral sinus. 
Development.-The parietal bone is formed in membrane, being developed by 
one centre, which corresponds with the parietal eminence, and makes its first appear- 
ance about the seventh or eighth week of foetal life. Ossification gradually extends 
from the centre to the circumference of the bone: the angles are consequently the 
parts last formed, and it is in their situation that the fontanelles exist previous to 
the completion of the growth of the bone. 
Articulations.-With five bones: the opposite parietal, the occipital, frontal, 
temporal, and sphenoid. 
Attachment of Muscles.-One only, the Temporal. 
The Frontal. Bone. 
The Frontal Bone (/rows, the forehead) resembles a cockle-shell in form, and 
consists of two portions-a vertical or frontal portion, situated at the anterior part 
of the cranium, forming the forehead; and a horizontal or orbito-nasal portion, 
which enters into the formation of the roof of the orbits and nasal fossae. 
Vertical Portion, external surface (Fig. 139).-In the median line, traversing 
the bone from the upper to the lower part, is occasionally seen a slightly elevated 
ridge, and in young subjects a suture, which represents the line of union of the two 
lateral halves of which the bone consists at an early period of life: in the adult this THE FRONTAL BONE. 
167 
suture is usually obliterated and the bone forms one piece; traces of the obliterated 
suture are, however, generally perceptible at the lower part. On either side of this 
ridge, a little below the centre of the bone, is a rounded eminence, the frontal emi- 
nence. These eminences vary in size in different individuals, and are occasionally 
unsymmetrical in the same subject. They are especially prominent in cases of well- 
marked cerebral development. The whole surface of the bone above this part is smooth, 
and covered by the aponeurosis of the Occipito-frontalis muscle. Below the frontal 
eminence, and separated from it by a slight groove, is the superciliary ridge, broad 
internally where it is continuous with the nasal eminence, but less distinct as it 
arches outward. These ridges are caused by the projection outward of the frontal 
sinuses,1 and give attachment to the Orbicularis palpebrarum and Corrugator super- 
Fig. 139. 
Internet/1 
Angular Jiroc. 
External 
Angular jiroc. 
Nasal 
Sjiine 
Frontal Bone, outer surface. 
cilii. Beneath the superciliary ridge is the supraorbital arch, a curved and promi- 
nent margin which forms the upper boundary of the orbit and separates the vertical 
from the horizontal portion of the bone. The outer part of the arch is sharp and 
prominent, affording to the eye, in that situation, considerable protection from 
injury ; the inner part is less prominent. At the junction of the internal and mid- 
dle third of this arch is a notch, sometimes converted into a foramen by a bony pro- 
cess, and called the supraorbital notch or foramen. It transmits the supraorbital 
artery, vein, and nerve. A small aperture is seen in the upper part of the notch, 
1 Some confusion is occasioned to students commencing the study of anatomy by the name "sinuses" 
having been given to two perfectly different kinds of spaces connected with the skull. It may 
be as well, therefore, to state here, at the outset, that the " sinuses " on the interior of the cranium, 
marked by grooves on the inner surface of the bones, are venous channels along which the blood 
runs in its passage back from the brain, while the "sinuses" external to the cranial cavity (the 
frontal, ethmoidal, sphenoidal, and maxillary) are hollow spaces in the bones themselves which com- 
municate with the nostrils and contain air. 168 
THE SKELETON. 
which transmits a vein from the diploe to join the ophthalmic vein. The supraorbi- 
tal arch terminates externally in the external angular process, and internally in the 
internal angular process. The external angular process is strong, prominent, and 
articulates with the malar bone; running upward and backward from it is a sharp 
curved crest, the temporal ridge, for the attachment of the temporal fascia; and 
beneath it a slight concavity, that forms the anterior part of the temporal fossa and 
gives origin to the Temporal muscle. The internal angular processes are less marked 
than the external, and articulate with the lachrymal bones. Between the internal 
angular processes is a rough, uneven interval, the nasal notch, which articulates in 
the middle line with the nasal bone and on either side with the nasal process of the 
superior maxillary bone. The notch is continuous below with a long pointed process, 
the nasal spine. Above the nasal notch and between the two superciliary ridges is 
a projection, the nasal eminence or glabella, which denotes the position of the frontal 
sinuses. 
Internal Surface (Fig. 140).-Along the middle line is a vertical groove, the 
edges of which unite below to form a ridge, the frontal crest; the groove lodges the 
Fig. 140. 
•with Sup.Maxill- 
'Frontal Sinus 
•with Perpendicular jdafo of Ethmoid 
•with Nasal 
\ Expanded base of Nasal Spine, 
forming part cf Roof f Nose 
Frontal Bone, inner surface. 
superior longitudinal sinus, whilst its margins afford attachment to the falx cerebri. 
The crest terminates below at a small notch which is converted into a foramen by 
articulation with the ethmoid. It is called the foramen coecum, and varies in size 
in different subjects; it is sometimes partially or completely impervious, lodges a 
process of the falx cerebri, and, when open, transmits a vein from the lining mem- 
brane of the nose to the superior longitudinal sinus. On either side of the groove 
the bone is deeply concave, presenting eminences and depressions for the convolu- 
tions of the brain, and numerous small furrows for lodging the ramifications of the THE FRONTAL BONE. 
169 
anterior meningeal arteries. Several small irregular fossae are also seen on either 
side of the groove, for the reception of the Pacchionian bodies. 
Horizontal Portion, external surface.-This portion of the bone consists of 
two thin plates which form the vault of the orbit, separated from one another by 
the ethmoidal notch. Each orbital vault consists of a smooth, concave, triangular 
plate of bone, marked at its anterior and external part (immediately beneath the 
external angular process) by a shallow depression, the lachrymal fossa, for lodging 
the lachrymal gland; and at its anterior and internal part by a depression (some- 
times a small tubercle [or a hook]), for the attachment of the fibro-cartilaginous pulley 
of the Superior oblique muscle. The ethmoidal notch separates the two orbital 
plates: it is quadrilateral, and filled up, when the bones are united, by the cribri- 
form plate of the ethmoid. The margins of this notch present several half-cells, 
which, when united with corresponding half-cells on the upper surface of the eth- 
moid, complete the ethmoidal cells; two grooves are also seen crossing these edges 
transversely; they are converted into canals by articulation with the ethmoid, and 
are called the anterior and posterior ethmoidal canals: they open on the inner wall 
of the orbit. The anterior one transmits the nasal nerve and anterior ethmoidal 
vessels, the posterior one the posterior ethmoidal vessels. In front of the ethmoidal 
notch is the nasal spine, a sharp-pointed eminence which projects downward and 
forward, and articulates in front with the crest of the nasal bones; behind, it is 
marked by two grooves separated by a vertical ridge; the ridge articulates with the 
perpendicular lamellae of the ethmoid; the grooves form part of the roof of the 
nasal fossae. On either side of the base of the nasal spine are the openings of the 
frontal sinuses. These are two irregular cavities which extend upward and outward 
a variable distance between the two tables of the skull, and are separated from one 
another by a thin bony septum. They give rise to the prominences above the root 
of the nose called the nasal eminence and superciliary ridges. In the child they are 
generally absent, and they become gradually developed as age advances. These 
cavities vary in size in different persons, are larger in men than in women, and are 
frequently of unequal size on the two sides, the left being commonly the larger. 
Occasionally they are subdivided by incomplete bony laminae. They are lined by 
mucous membrane, and communicate with the nose by the infundibulum, and occa- 
sionally with each other by apertures in their septum. 
The internal surface of the Horizontal Portion presents the convex upper 
surfaces of the orbital plates, separated from each other in the middle line by the 
ethmoidal notch, and marked by eminences 
and depressions for the convolutions of the 
anterior lobes of the brain. 
Borders.-The border of the vertical por- 
tion is thick, strongly serrated, bevelled at 
the expense of the internal table above, where 
it rests upon the parietal bones, and at the 
expense of the external table at each side, 
where it receives the lateral pressure of those 
bones ; this border is continued below into a 
triangular rough surface which articulates 
with the great wing of the sphenoid. The 
border of the horizontal portion is thin, ser- 
rated, and articulates with the lesser wing of 
the sphenoid. 
Structure.-The vertical portion and ex- 
ternal angular processes are very thick, consisting of diploic tissue contained between 
two compact laminae. The horizontal portion is thin, translucent, and composed 
entirely of compact tissue; hence the facility with which instruments can penetrate 
the cranium through this part of the orbit. 
Development (Fig. 141).-The frontal bone is formed in membrane, being 
developed by two centres, one for each lateral half, which make their appearance 
Fig. 141. 
Frontal Bone at Birth, developed by two lateral 
halves. 170 
THE SKELETON. 
about the seventh or eighth week above the orbital arches. From this point ossifi- 
cation extends, in a radiating manner, upward into the forehead and backward over 
the orbit. At birth the bone consists of two pieces, which afterward become united, 
along the middle line, by a suture which runs from the vertex to the root of the 
nose. This suture usually becomes obliterated within a few years after birth, but it 
occasionally remains throughout life. 
Articulations.-With twelve bones: two parietal, the sphenoid, the ethmoid, 
two nasal, two superior maxillary, two lachrymal, and two malar. 
Attachment of Muscles.-To three pairs: the Corrugator supercilii, Orbicularis 
palpebrarum, and Temporal, on each side. 
The Temporal Bones (tempus, time) are situated at the side and base of the 
skull, and present for examination a squamous, mastoid, and petrous portion. 
The Squamous Portion (squama, a scale) (Fig- 142), the anterior and upper 
part of the bone, is scale-like in form and thin and translucent in texture. Its 
outer surface is smooth, convex, and grooved at its back part for the deep temporal 
The Temporal Bones. 
Fig. 142. 
.Mastai cl foramen 
Stylo-glossus- 
STYLOHYOID 
Left Temporal Bone, outer surface. 
arteries: it affords attachment to the Temporal muscle and forms part of the tem- 
poral fossa. At its back part may be seen a curved ridge, part of the temporal 
ridge ; it serves for the attachment of the temporal fascia, limits the origin of the 
Temporal muscle, and marks the boundary between the squamous and mastoid por- 
tions of the bone. Projecting from the lower part of the squamous portion is a long 
arched process of bone, the zygoma [or zygomatic process. This process can always 
be felt, and often seen, as a marked elevation. In the Carnivora it is very strong, 
and projects enormously on account of their powerful muscles of mastication]. This THE TEMPORAL BONES. 
171 
process is at first directed outward, its two surfaces looking upward and downward; 
it then appears as if twisted upon itself, and runs forward, its surfaces now looking 
inward and outward. The superior border of the process is long, thin, and sharp, 
and serves for the attachment of the temporal fascia. The inferior, short, thick, and 
arched, has attached to it some fibres of the Masseter muscle. Its outer surface is 
convex and subcutaneous; its inner is concave, and also affords attachment to the 
Masseter. The extremity, broad and deeply serrated, articulates with the malar 
bone. The zygomatic process is connected to the temporal bone by three divisions, 
called its roots-an anterior, middle, and posterior. The anterior, which is short 
but broad and strong, is directed inward, to terminate in a rounded eminence, the 
eminentia articularis. This eminence forms the front boundary of the glenoid 
fossa, and in a recent state is covered with cartilage. The middle root forms the 
outer margin of the glenoid cavity; running obliquely inward, it terminates at the 
commencement of a well-marked fissure, the Grlaserian fissure; whilst the posterior 
root, wThich is strongly marked, runs from the upper border of the zygoma in an 
arched direction upward and backward, forming the posterior part of the temporal 
ridge. At the junction of the anterior root with the zygoma is a projection, called 
the tubercle, for the attachment of the external lateral ligament of the lower jaw; 
and between the anterior and middle roots is an oval depression, forming part of the 
glenoid fossa (yk/pap a socket), for -the reception of the condyle of the lower jaw. 
This fossa is bounded in front by the eminentia articularis; behind, by the vaginal 
process; and externally, by the auditory process and middle root of the zygoma; 
and is divided into two parts by a narrow slit, the Grlaserian fissure. The anterior 
part, formed by the squamous portion of the bone, is smooth, covered in the recent 
state with cartilage, and articulates with the condyle of the lower jaw. This part 
of the glenoid fossa is separated from the auditory process by a small tubercle, the 
post-glenoid process, the representative of a prominent tubercle which, in some of 
the Mammalia, descends behind the condyle of the jaw and prevents its being dis- 
placed backward during mastication (Humphry). The posterior part of the glenoid 
fossa is formed chiefly by the tympanic plate, a lamina of bone which forms the 
anterior wall of the tympanum and external auditory meatus. This plate of bone 
terminates externally in the auditory process, above in the Glaserian fissure, and 
below forms a sharp edge, the vaginal process. It lodges a portion of the parotid 
gland, and gives origin to some of the fibres of the Tensor palati muscle. The 
Glaserian fissure, which leads into the tympanum, lodges the processus gracilis of 
the malleus and transmits the tympanic branch of the internal maxillary artery. 
The chorda tympani nerve passes through a separate canal, parallel to the Glaserian 
fissure (canal of Huguier), on tire outer side of the Eustachian tube, in the retiring- 
angle between the squamous and petrous portions of the temporal bone.1 
The internal surface of the squamous portion (Fig. 144) is concave-presents 
numerous eminences and depressions for the convolutions of the cerebrum, and two 
well-marked grooves for the branches of the middle meningeal artery. 
Borders.-The superior border is thin, bevelled at the expense of the internal 
surface, so as to overlap the lower border of the parietal bone, forming the squamous 
suture. The anterior inferior border is thick, serrated, and bevelled, alternately at 
the expense of the inner and outer surfaces, for articulation with the great wing of 
the sphenoid. 
The Mastoid Portion (paa-bt;, a nipple or teat) is situated at the posterior part 
of the bone; its outer surface is rough and perforated by numerous foramina; one 
of these, of large size, situated at the posterior border of the bone, is termed the 
mastoid foramen; it transmits a vein to the lateral sinus and a small artery from 
the occipital, to supply the dura mater. The position and size of this foramen are 
very variable. It is not always present; sometimes it is situated in the occipital 
bone or in the suture between the temporal and the occipital. The mastoid portion 
is continued below into a conical projection, the mastoid process, the size and form 
1 This small fissure must not be confounded with the large canal which lies above the Eustachian 
tube and transmits the Tensor tympani muscle. 172 
THE SKELETON. 
of which vary somewhat. This process serves for the attachment of the Sterno- 
mastoid, Splenitis capitis, and Trachelo-mastoid 
muscles. On the inner side of the mastoid pro- 
cess is a deep groove, the digastric fossa, for the 
attachment of the Digastric muscle, and running 
parallel with it, but more internal, the occipital 
groove, which lodges the occipital artery. The 
internal surface of the mastoid portion presents a 
deep curved groove, the fossa Sigmoidea, which 
lodges part of the lateral sinus, and into it may 
be seen opening the mastoid foramen. A section 
of the mastoid process shows it to be hollowed out 
into a number of cellular spaces communicating 
with each other, called the mastoid cells; they 
open by a single or double orifice into the back 
of the tympanum, are lined by a prolongation of 
its lining membrane, and probably form some sec- 
ondary part of the organ of hearing. The mastoid 
cells, like the other sinuses of the cranium, are 
not developed until after puberty; hence the prom- 
inence of this process in the adult. [Fig- 143 
shows their communication with the middle ear. By 
this route inflammation and suppuration may readily 
extend into these cells as a result of ear disease, pro- 
ducing "mastoid disease." Unless speedily relieved 
by trephining, this often produces death by involv- 
ing the brain. The very thin bony septum which separates the mastoid cells and 
middle ear from the cranial cavity is also well shown in the figure.] 
[Fig. 143. 
MASTOID CELLS 
Section through the Mastoid Cells, show- 
ing their communication with the mid- 
dle ear.-W. W. K.] 
Fig. 144. 
Aqucd'ibetii* Vesti.bult. 
DejjTcssiun far Dara-niate'r 
Meatus Auditurms mternus 
Wmiiu-nce jor Superior S'e-i/deirnilar Canal 
~~ Hiatus FajLCopiL 
"■Ope/ning J or Smaller Petrosal Nerve, 
Depression for Gasserian gaiiqlzon 
Bristle passed tliroM/k Carotid Canal 
Left Temporal Bone, inner surface. THE TEMPORAL BONES. 
173 
Borders.-The superior border of the mastoid portion is broad and rough, its 
serrated edge sloping outward, for articulation with the posterior inferior angle 
of the parietal bone. The posterior border, also uneven and serrated, articulates 
with the inferior border of the occipital bone between its lateral angle and jugular 
process. 
The Petrous Portion (fterpoz, a stone), so named from its extreme density and 
hardness, is a pyramidal process of bone wedged in at the base of the skull between 
the sphenoid and occipital bones. Its direction from without is inward, forward, and 
a little downward. It presents for examination a base, an apex, three surfaces, and 
three borders, and contains in its interior the essential parts of the organ of hear- 
ing. The base is applied against the internal surface of the squamous and mastoid 
portions, its upper half being concealed; but its lower half is exposed by the diver- 
gence of those two portions of the bone, which brings into view the oval expanded 
orifice of a canal leading into the tympanum, the meatus auditorius externus. This 
canal is situated in front of the mastoid process and between the posterior and mid- 
dle roots of the zygoma; its upper margin is smooth and rounded, but the greater 
part of its circumference is surrounded by a curved plate of bone, the auditory pro- 
cess, the free margin of which is thick and rough, for the attachment of the cartilage 
of the external ear. 
The apex of the petrous portion, rough and uneven, is received into the angular 
interval between the posterior border of the greater wing of the sphenoid and the 
Fig. 145. 
Canals fa- tube 
and Tensortynijftanimusclei 
LEVATOR palati 
.TENSOR 
Jtympani 
Rough Quadrilateral Surface - 
Openivcj of carotid carnal- 
Canal for Jacobson s nerve-- 
Aqueduct,us Coc/dece,- 
Canal fo r A mold's nerve -" 
Jugular fossa -- 
Vagi nal process 
Styloid, 
Stylo- mastoid foramen ■ 
Jugular Surface' 
Auricular fissure 
STYLO-PHaRYNGEUS 
Petrous Portion, inferior surface. 
basilar process of the occipital; it presents the anterior or internal orifice of the 
carotid canal, and forms the posterior and external boundary of the foramen lacerum 
medium. 
lhe anterior surface of the petrous portion (Fig. 145) forms the posterior part 
of the middle fossa of the skull This surface is continuous with the squamous por- 174 
THE SKELETON. 
tion, to which it is united by a suture, the temporal suture, the remains of which are 
distinct even at a late period of life; it presents six points for examination: 1, An 
eminence near the centre, which indicates the situation of the superior semicircular 
canal; 2, on the outer side of this eminence a depression, indicating the position of 
the tympanum, the layer of bone which separates the tympanum from the cranial 
cavity being extremely thin; 3, a shallow groove, sometimes double, leading out- 
ward and backward to an oblique opening, the hiatus Fallopii, for the passage of 
the petrosal branch of the Vidian nerve and a branch of the middle meningeal 
artery; 4, a smaller opening, occasionally seen external to the latter, for the 
passage of the smaller petrosal nerve; 5, near the apex of the bone the termi- 
nation of the carotid canal, the wall of which in this situation is deficient in 
front; 6, above this canal a shallow depression for the reception of the Gasserian 
ganglion. 
The posterior surface forms the front part of the posterior fossa of the skull, 
and is continuous with the inner surface of the mastoid portion of the bone. It 
presents three points for examination : 1, About its centre a large orifice, the meatus 
auditorius internus, whose size varies considerably; its margins are smooth and 
rounded, and it leads into a short canal, about four lines in length, which runs 
directly outward and is closed by a vertical plate, the lamina cribrosa, which is 
divided by a horizontal crest into two unequal portions, the lower presenting several 
small apertures for the transmission of the filaments of the auditory nerve and the 
auditory artery, a branch of the basilar, the upper having one larger opening, the 
commencement of the aquseductus Fallopii, for the passage of the facial nerve; 2, 
behind the meatus auditorius a small slit, almost hidden by a thin plate of bone, 
leading to a canal, the aquceductus vestibuli, which transmits a small artery and 
vein and lodges a process of the dura mater; 3, in the interval between these 
two openings, but above them, an angular depression which lodges a process 
of the dura mater and transmits a small vein into the cancellous tissue of the 
bone. 
The inferior or basilar surface (Fig. 145) is rough and irregular, and forms 
part of the base of the skull. Passing from the apex to the base, this surface pre- 
sents eleven points for examination : 1, A rough surface, quadrilateral in form, which 
serves partly for the attachment of the Levator palati and Tensor tympani muscles; 
2, the large circular aperture of the carotid canal, which ascends at first vertically, 
and then, making a bend, runs horizontally forward and inward: it transmits the 
internal carotid artery and the carotid plexus; 3, the aquceductus cochlece, a small 
triangular opening lying on the inner side of the latter, close to the posterior border 
of the petrous portion : it transmits a vein from the cochlea which joins the internal 
jugular ; 4, behind these openings a deep depression, the jugular fossa, which varies 
in depth and size in different skulls : it lodges the lateral sinus, and, with a similar 
depression on the margin of the jugular process of the occipital bone, forms the for- 
amen lacerum posterius [or jugular foramen] ; 5, a small foramen for the passage of 
Jacobson's nerve (the tympanic branch of the glosso-pharyngeal): this foramen is 
seen in front of the bony ridge dividing the carotid canal from the jugular fossa; 6, 
a small foramen on the outer wall of the jugular fossa, for the entrance of the auric- 
ular branch of the pneumogastric (Arnold's) nerve; 7, behind the jugular fossa a 
smooth, square-shaped facet, the jugular surface: it is covered with cartilage in the 
recent state, and articulates with the jugular process of the occipital bone; 8, the 
vaginal process, a very broad, sheath-like plate of bone which extends from the 
carotid canal to the mastoid process: it divides behind into two laminae, receiving 
between them the ninth point for examination, the styloid process, a long sharp 
spine about an inch in length: it is directed downward, forward, and inward, varies 
in size and shape, and sometimes consists of several pieces united by cartilage: it 
affords attachment to three muscles, the Stylo-pharyngeus, Stylo-hyoideus, and 
Stylo-glossus, and two ligaments, the stylo-hyoid and stylo-maxillary; 10, the stylo- 
mastoid foramen, a rather large orifice, placed between the styloid and mastoid pro- 
cesses: it is the termination of the aquseductus Fallopii, and transmits the facial THE TEMPORAL BONES. 
175 
nerve and stylo-mastoid artery; 11, the auricular fissure, situated between the 
vaginal and mastoid processes, for the exit of the auricular branch of the pneu- 
mogastric nerve. 
Borders.-The superior, the longest, is grooved for the superior petrosal sinus, 
and has attached to it the ■tentorium cerebelli; at its inner extremity is a semilunar 
notch, upon which the fifth nerve lies. The posterior border is intermediate in length 
between the superior and the anterior. Its inner half is marked by a groove which, 
when completed by its articulation with the occipital, forms the channel for the 
inferior petrosal sinus. Its outer half presents a deep excavation-the jugular fossa 
-which, with a similar notch on the occipital, forms the foramen lacerum posterius. 
A projecting eminence of bone occasionally stands out from the centre of the notch 
and divides the foramen into two parts. The anterior border is divided into two 
parts-an outer, joined to the squamous portion by a suture, the remains of which 
are distinct; an inner, free, articulating with the spinous process of the sphenoid. 
At the angle of junction of the petrous and squamous portions are seen two canals, 
separated from one another by a thin plate of bone, the processus cochleariformis: 
they both lead into the tympanum, the upper one transmitting the Tensor tympani 
muscle, the lower one the Eustachian tube. 
Structure.-The squamous portion is like that of the other cranial bones, the 
mastoid portion cellular, and the petrous portion dense and hard. 
Development (Fig. 146).-The temporal bone is developed by ten centres, 
exclusive of those for the internal ear and the ossicula-viz. one for the squamous 
portion, including the zygoma, one for the 
auditory process (tympanic ring), six for 
the petrous and mastoid parts, and two 
for the styloid process. Just before the 
close of foetal life the temporal bone con- 
sists of four parts: 1. The squamo-zygo- 
matic, which is ossified in membrane from 
a single nucleus which appears at its 
lowei* part about the second month. 2. 
The auditory process, an imperfect ring 
which encloses the tympanic membrane. 
This is also ossified from a single centre, 
which appears rather later than that for 
the squamous portion. 3. The petro- 
mastoid, which is developed from six 
centres, which appear about the fifth 
or sixth month. Four of these are 
for the petrous portion, and are placed 
around the labyrinth, and two for the 
mastoid (Vrolik). According to Hux- 
ley, the centres are more numerous and 
are disposed so as to form three por- 
tions : (1) Including most of the laby- 
rinth, with a part of the petrous and mastoid, he has named prootic; (2) the rest 
of the petrous, the opisthotic ; and (3) the remainder of the mastoid, the epiotic. 
The petro-mastoid is ossified in cartilage. 4. The styloid process is also ossified in 
cartilage from two centres-one for the base, which appears before birth and is 
termed the tympano-hyal; the other, comprising the rest of the process, is named 
the stylo-hyal, and does not appear until after birth. Shortly before birth the audi- 
tory process joins with the squamous. The petrous and mastoid join with the 
squamous during the first year, and the tympano-hyal portion of the styloid process 
about the same time. The stylo-hyal does not join the rest of the bone until after 
puberty, and in some skulls never becomes united. The subsequent changes in this 
bone are, that the auditory process extends outward, so as to form the meatus audi- 
torius; the glenoid fossa becomes deeper; and the mastoid part, which at an early 
Fig. 146. 
1 for Squamous 
portion including 
Zygoma,. 
mo- 
At Birth <3 pieces s epee-rate 
a 72it'& during year 
L for Auditory 
jjroeess 
6 for JPetTous 
Be fiFa.staid 
portions 
2for Styloid proc. 
Development of the Temporal Bone, by ten centres. 176 
THE SKELETON. 
period of life is quite flat, enlarges from the development of the cellular cavities in 
its interior. 
Articulations.-With five bones-occipital, parietal, sphenoid, inferior maxil- 
lary, and malar. 
Attachment of Muscles.-To fifteen : to the squamous portion, .the Temporal -, 
to the zygoma, the Masseter; to the mastoid portion, the Occipito-frontalis, Sterno- 
mastoid, Splenius capitis, Trachelo-mastoid, Digastricus, and Retrahens aurem; to 
the styloid process, the Stylo-pharyngeus, Stylo-hyoideus, and Stylo-glossus; and 
to the petrous portion, the Levator palati, Tensor tympani, Tensor palati, and 
Stapedius. 
The Sphenoid Bone. 
The Sphenoid Bone (oipgv, a wedge) is situated at the anterior part of the base 
of the skull, articulating with all the other cranial bones, which it binds firmly and 
solidly together. In its form it somewhat resembles a bat with its wings extended, 
and is divided into a central portion or body, two greater and two lesser wings 
extending outward on each side of the body; and two processes-the pterygoid 
processes-which project from it below. 
The Body is of large size, cuboid in form, and hollowed out in its interior so as 
to form a mere shell of bone. It presents for examination four surfaces-a superior, 
an inferior, an anterior, and a posterior. 
The Superior Surface (Fig. 147).-In front is seen a prominent spine, the eth- 
moidal spine, for articulation with the cribriform plate of the ethmoid; behind this, 
a smooth surface presenting, in the median line, a slight longitudinal eminence, 
with a depression on each side, for lodging the olfactory nerves. A narrow trans- 
verse groove, the optic groove, bounds the above-mentioned surface behind ; it lodges 
the optic commissure, and terminates on either side in the optic foramen, for the 
passage of the optic nerve and ophthalmic artery. Behind the optic groove is a 
small eminence, olive-like in shape, the olivary process ; and still more posteriorly, 
a deep depression, the pituitary fossa, or sella Turcica, which lodges the pituitary 
body. This fossa is perforated by numerous foramina for the transmission of 
Fig.147. 
Middle Clinoid process 
Posterior Ctinoicl process 
EtJinwidal Spina 
< Groove for 
Ulfiuitory nerve 
Foramen 
FoTamen Lace.TU.in 
ITltcriU'S, ov SpheieoaialFlseiLTe 
Fumrnen Jlotu.nJu.iii,-''' 
n VcsaJiu ■' 
„ Ovale 
h Spi'nusam - 
for nerve 
Sphenoid Bone, superior surface. 
nutrient vessels into the substance of the bone. It is bounded in front by two small 
eminences, one on either side, called the middle clinoid processes (plvrp a bed), and 
behind by a square-shaped plate of bone, the dorsum ephippii or dorsum sellce, ter- THE SPHENOID BONE. 
177 
minating at each superior angle in a tubercle, the posterior clinoid processes, the 
size and form of which vary considerably in different individuals. These processes 
deepen the pituitary fossa, and serve for the attachment of prolongations from the 
tentorium cerebelli. The sides of the dorsum ephippii are notched for the passage 
of the sixth pair of nerves, and behind this plate of bone presents a shallow depres- 
sion, which slopes obliquely backward and is continuous with the basilar groove of 
the occipital bone ; it is called the clivus Blumenbachii, and supports the upper part 
of the pons Varolii. On either side of the body is a broad groove, curved some- 
thing like the italic letter/; it lodges the internal carotid artery and the cavernous 
sinus, and is called the carotid or cavernous groove. Along the outer margin of this 
groove, at its posterior part, is a ridge of bone called the lingula. The posterior 
surface, quadrilateral in form, is joined to the basilar process of the occipital bone. 
During childhood these bones are separated by a layer of cartilage, but in after-life 
(between the eighteenth and twenty-fifth years) this becomes ossified, ossification 
commencing above and extending downward, and the two bones then form one piece. 
The anterior surface (Fig. 148) presents, in the middle line, a vertical lamella of 
bone, the ethmoidal crest, which articulates in front with the perpendicular plate of 
the ethmoid, forming part of the septum of the nose. On either side of it are the 
irregular openings leading into the sphenoidal cells or sinuses. [See Fig. 181.] 
Fig. 148. 
Ethmoidal crest, 
Artir -nitjo EirfwndleulUT 
Elate/tf Ethmoid 
Orbital 
Surface of 
G reater Wing 
.ftwggold Ridge 
IPte rye/ o- 
Vpedatme 
' Canal t 
groove frr ala 
"/* v°mer / 
I r I 
■LAXATOR TYMPANI 
Rostrum./ 
Internal Etcrggoid, filat/ 
iLuenulte/r'_ /l/rocess - 
Sphenoid Bone, anterior surface.1 
These are two large irregular cavities hollowed out of the interior of the body of 
the sphenoid bone, and separated from one another by a more or less complete per- 
pendicular bony septum. Their form and size vary considerably; they are seldom 
symmetrical, and are often partially subdivided by irregular osseous laminae. Occa- 
sionally they extend into the basilar process of the occipital nearly as far as the 
foramen magnum. The septum is seldom quite vertical, being commonly bent to 
one or the other side. These sinuses do not exist in children, but they increase in 
size as age advances. They are partially closed, in front and below, by two thin 
curved plates of bone, the sphenoidal turbinated bones, leaving a round opening at 
their upper parts, by which they communicate with the upper and back part of the 
nose, and occasionally with the posterior ethmoidal cells or sinuses. The lateral 
margins of this surface present a serrated edge which articulates with the os planum 
of the ethmoid, completing the posterior ethmoidal cells; the lower margin, also 
1 In this figure both the anterior and inferior surfaces of the body of the sphenoid bone are 
shown, the bone being held with the pterygoid processes almost horizontal. 178 
THE SKELETON. 
rough and serrated, articulates with the orbital process of the palate bone, and 
the upper margin with the orbital plate of the frontal bone. The inferior surface 
presents, in the middle line, a triangular spine, the rostrum, which is continuous 
with the vertical plate on the anterior surface, and is received into a deep fissure 
between the alm of the vomer. On each side may be seen a projecting lamina of 
bone which runs horizontally inward from near the base of the pterygoid process: 
these plates, termed the vaginal processes, articulate with the edges of the vomer. 
Close to the root of the pterygoid process is a groove, formed into a complete canal 
when articulated with the sphenoidal process of the palate bone; it is called the 
pterygo-palatine canal, and transmits the pterygo-palatine vessels and pharyngeal 
nerve. 
The Greater Wings are two strong processes of bone which arise from the sides 
of the body, and are curved in a direction upward, outward, and backward, being 
prolonged behind into a sharp-pointed extremity, the spinous process of the sphe- 
noid. Each wing presents three surfaces and a circumference. The superior or 
cerebral surface (Fig. 147) forms part of the middle fossa of the skull; it is deeply 
concave, and presents eminences and depressions for the convolutions of the brain. 
At its anterior and internal part is seen a circular aperture, the foramen rotundum, 
for the transmission of the second division of the fifth nerve. Behind and external 
to this is a large oval foramen, the foramen ovale, for the transmission of the third 
division of the fifth nerve, the small meningeal artery, and sometimes the small 
petrosal nerve.1 At the inner side of the foramen ovale a small aperture may occa- 
sionally be seen opposite the root of the pterygoid process ; it is the foramen Vesalii, 
transmitting a small vein. Lastly, in the posterior angle, near to the spine of the 
sphenoid, is a short canal, sometimes double, the foramen spinosum; it transmits 
the middle meningeal artery. The external surface (Fig. 148) is convex, and 
divided by a transverse ridge, the pterygoid ridge, into two portions. The supe- 
rior or larger, convex from above downward, concave from before backward, enters 
into the formation of the temporal fossa and gives attachment to part of the Tem- 
poral muscle. The inferior portion, smaller in size and concave, enters into the 
formation of the zygomatic fossa and affords attachment to the External pterygoid 
muscle. It presents, at its posterior part, a sharp-pointed eminence of bone, the 
spinous process, to which are connected the internal lateral ligament of the lower 
jaw and the Tensor palati muscle. The pterygoid ridge, dividing the temporal and 
zygomatic portions, gives attachment to part of the External pterygoid muscle. At 
its inner and anterior extremity is a triangular spine of bone which serves to increase 
the extent of origin of this muscle. The anterior or orbital surface, smooth and 
quadrilateral in form, assists in forming the outer wall of the orbit. It is bounded 
above by a serrated edge, for articulation with the frontal bone; below, by a 
rounded border which enters into the formation of the spheno-maxillary fissure; 
internally, it presents a sharp border which forms the lower boundary of the sphe- 
noidal fissure, and has projecting from about its centre a little tubercle of bone, 
which gives origin to one head of the external rectus muscle of the eye, and at its 
upper part is a notch for the transmission of a branch of the ophthalmic artery; 
externally it presents a serrated margin for articulation with the malar bone. One 
or two small foramina may occasionally be seen for the passage of branches of the 
deep temporal arteries ; they are called the external orbital foramina. Circumfer- 
ence of the great wing (Fig. 147): commencing from behind, from the body of the 
sphenoid to the spine, the outer half of this margin is serrated, for articulation with 
the petrous portion of the temporal bone, whilst the inner half forms the anterior 
boundary of the foramen lacerum medium and presents the posterior aperture of the 
Vidian canal. In front of the spine the circumference of the great wing presents a 
serrated edge, bevelled at the expense of the inner table below and of the external 
above, which articulates with the squamous portion of the temporal bone. At the 
tip of the great wing a triangular portion is seen, bevelled at the expense of the 
1 The small petrosal nerve sometimes passes through a special foramen between the foramen ovale 
and foramen spinosum. THE SPHENOID BONE. 
179 
internal surface, for articulation with the anterior inferior angle of the parietal 
bone. Internal to this is a broad serrated surface, for articulation with the frontal 
bone: this surface is continuous internally with the sharp inner edge of the orbital 
plate, which assists in the formation of the sphenoidal fissure. 
The Lesser Wings {processes of Ingrassias) are two thin triangular plates of 
bone which arise from the upper and lateral parts of the body of the sphenoid, and, 
projecting transversely outward, terminate in a sharp point (Fig. 147). The supe- 
rior surface of each is smooth, flat, broader internally than externally, and supports 
the anterior lobe of the brain. The inferior surface forms the back part of the 
roof of the orbit and the upper boundary of the sphenoidal fissure or foramen lace- 
rum anterius. This fissure is of a triangular form, and leads from the cavity of the 
cranium into the orbit; it is bounded internally by the body of the sphenoid-above 
by the lesser wing, below by the internal margin of the orbital surface of the great 
wing-and is converted into a foramen by the articulation of this bone with the 
frontal. It transmits the third, the fourth, the ophthalmic division of the fifth, and 
[the] sixth cranial nerves, some filaments from the cavernous plexus of the sympa- 
thetic, the orbital branch of the middle meningeal artery, a recurrent branch from 
the lachrymal artery to the dura mater, and the ophthalmic vein. The anterior 
border of the lesser wing is serrated for articulation with the frontal bone; the 
posterior, smooth and rounded, is received into the fissure of Sylvius of the brain. 
The inner extremity of this border forms the anterior clinoid process. The lesser 
wing is connected to the side of the body by two roots, the upper thin and flat, the 
lower thicker, obliquely directed, and presenting on its outer side, near its junction 
with the body, a small tubercle, for the attachment of the common tendon of three 
of the muscles of the eye. Between the two roots is the optic foramen, for the 
transmission of the optic nerve and ophthalmic artery. 
The Pterygoid. Processes {TvrepvS, a wing; s.H6oq, likeness) (Fig. 149), one on 
each side, descend perpendicularly from the point where the body and greater wing 
unite. Each process consists of an external and an internal plate, separated behind 
by an intervening notch, the 
pterygoid fossa, but joined 
partially in front. The ex- 
ternalpterygoid plate is broad 
and thin, turned a little out- 
ward, and forms part of the 
inner wall of the zygomatic 
fossa. It gives attachment, 
by its outer surface, to the 
External pterygoid; its inner 
surface forms part of the 
pterygoid fossa, and gives at- 
tachment to the Internal 
pterygoid. The internal ptery- 
goid plate is much narrower 
and longer, curving outward 
at its extremity into a hook- 
like process of bone, the ham- 
ular proems, around which 
turns the tendon of the Tensor palati muscle. At the base of this plate is a small, 
oval, shallow depression, the scaphoid fossa, from which arises the Tensor palati, 
and above which is seen the posterior orifice of the Vidian canal. The outer sur- 
face of this plate forms part of the pterygoid fossa, the inner surface forming the 
outer boundary of the posterior aperture of the nares. The Superior constrictor 
of the pharynx is attached to its posterior edge. The two pterygoid plates are sep- 
arated below by an angular interval, in which the pterygoid process or tuberosity of 
the palate bone is received. The anterior surface of the pterygoid process is very 
broad at its base, and forms the posterior wall of the spheno-maxillary fossa. It 
Fig. 149. 
Sphenoid Bone, posterior surface. 180 
THE SKELETON. 
supports Meckel's ganglion. It presents above the anterior orifice of the Vidian 
canal, and below a rough margin which articulates with the perpendicular plate of 
the palate bone. 
The Sphenoidal Turbinated or Sphenoidal Spong-y Bones [Fig. 148] are 
two thin curved plates of bone, which exist as separate pieces until puberty, and occa- 
sionally are not joined to the sphenoid in the adult. They are situated at the ante- 
rior and inferior part of the body of the sphenoid, an aperture of variable size being 
left in their anterior wall, through which the sphenoidal sinuses open into the nasal 
fossae. They are irregular in form, and taper to a point behind, being broader and 
thinner in front. Their inner surface, which looks toward the cavity of the sinus, 
is concave; their outer surface, convex. Each bone articulates in front with the 
ethmoid, externally with the palate; its pointed posterior extremity is placed above 
the vomer, and is received between the root of the pterygoid process on the outer 
side and the rostrum of the sphenoid on the inner.1 
Development.-Up to about the eighth month of foetal life the sphenoid bone 
consists of two distinct parts: a posterior 
or postsphenoid part, which comprises the 
pituitary fossa, the greater wings, and the 
pterygoid processes; and an anterior or 
presphenoid part, to which the anterior 
part of the body and lesser wings belong. 
It is developed by fourteen centres-eight 
for the posterior sphenoid division, and six 
for the anterior sphenoid. The eight cen- 
tres for the posterior sphenoid are-one for 
each greater wing and external pterygoid 
plate, one for each internal pterygoid plate, 
two for the posterior part of the body, and one 
on either side for the lingula. The six for 
the anterior sphenoid are-one for each less- 
er wing, two for the anterior part of the body, 
and one for each sphenoidal turbinated bone. 
Postsphenoid Division.-The first nuclei to appear are those for the greater 
wings. They make their appearance between the foramen rotundum and foramen 
ovale about the eighth week, and from them the external pterygoid plates are also 
formed. Soon after the nuclei for the posterior part of the body appear, one on 
either side of the sella Turcica, and become blended together about the middle of 
foetal life. About the fourth month the remaining four centres appear, those for the 
internal pterygoid plates being ossified in membrane and becoming joined to the 
external pterygoid plate about the sixth month. The centres for the lingulae speedily 
become joined to the rest of the bone. 
Presphenoid Division.-The first nuclei to appear are those for the lesser wings. 
They make their appearance about the ninth week at the outer borders of the optic 
foramina. A second pair of nuclei appear on the inner side of the foramina shortly 
after, and, becoming united, form the front part of the body of the bone. The 
remaining two centres for the sphenoidal turbinated bones do not make their appear- 
ance until the end of the third year, and become joined to the body of the bone 
after puberty. 
The presphenoid is united to the body of the postsphenoid about the eighth 
month, so that at birth the bone consists of three pieces-viz. the body in the centre, 
and on each side the great wings with the pterygoid processes. At the first year 
after birth the greater wings and body are united. From the tenth to the twelfth 
year the spongy bones are partially united to the sphenoid, their junction being 
Fig. 150. 
one for ocrdi two for arderior 
lesser urincj- jrart <rf body 
one for* ectcTtr internac 
jrteryymclplccte ~one 
one /or- /"or- ececfi. 7/n.tjrn/cf 
eaah, yrvai a-ncl enofemaZ- jofery- 
cne idjpTocte. 
for eotafb £f>7enoieZci/- ione 
Plan of the Development of Sphenoid, by fourteen 
centres. 
1 A small portion of the sphenoidal turbinated bone sometimes enters into the formation of the 
inner wall of the orbit, between the os planum of the ethmoid in front, the orbital plate of the palate 
below, and the frontal above (Cleland, Roy. Soc. Trans., 1862). THE ETHMOID BONE. 
181 
complete by the twentieth year. Lastly, the sphenoid joins the occipital from the 
eighteenth to the twenty-fifth year. 
Articulations.-The sphenoid articulates with all the bones of the cranium and 
five of the face-the two malar, two palate, and vomer: the exact extent of articu- 
lation with each bone is shown in the accompanying figures.1 
Attachment of Muscles.-To twelve pairs : the Temporal, External pterygoid, 
Internal pterygoid, Superior constrictor, Tensor palati, Laxator tympani, Levator 
palpebrse, Obliquus superior, Superior rectus, Internal rectus, Inferior rectus, 
External rectus. 
The Ethmoid Bone. 
The Ethmoid (yOgo', a sieve) is an exceedingly light, spongy bone, of a cubical 
form, situated at the anterior part of the base of the cranium, between the two 
orbits, at the root of the nose, and contributing to form each of these cavities. It 
consists of three parts: a horizontal plate, which forms part of the base of the 
cranium; a perpendicular plate, which forms part of the septum nasi; and two 
lateral masses of cells. 
The Horizontal or Cribriform Plate (Fig. 151) forms part of the anterior fossa 
of the base of the skull, and is received into the ethmoid notch of the frontal bone 
between the two orbital plates. Projecting upward from the middle line of this 
plate is a thick, smooth, trian- 
gular process of bone, the crista 
galli, so called from its resem- 
blance to a cock's comb. Its 
base joins the cribriform plate. 
Its posterior border, long, thin, 
and slightly curved, serves for 
the attachment of the falx cere- 
bri. Its anterior border, short 
and thick, articulates with the 
frontal bone, and presents two 
small projecting ahe, which are 
received into corresponding de- 
pressions in the frontal, com- 
pleting the foramen caecum be- 
hind. Its sides are smooth, and 
sometimes bulging, in which case 
it is found to enclose a small 
sinus.2 On each side of the 
crista galli the cribriform plate 
is narrow and deeply grooved, to support the bulb of the olfactory nerve, and per- 
forated by foramina for the passage of its filaments. These foramina are arranged 
in three rows: the innermost, which are the largest and least numerous, are lost in 
grooves on the upper part of the septum; the foramina of the outer row are con- 
tinued on to the surface of the upper spongy bone. The foramina of the middle 
row are the smallest; they perforate the bone and transmit nerves to the roof of 
the nose. At the front part of the cribriform plate, on each side of the crista galli, 
is a small fissure which transmits the nasal branch of the ophthalmic nerve, and 
at its posterior part a triangular notch which receives the ethmoidal spine of the 
sphenoid. 
The Perpendicular Plate (Fig. 152) is a thin, flattened lamella of bone which 
descends from the under surface of the cribriform plate and assists in forming the 
septum of the nose. It is much thinner in the middle than at the circumference, 
Fig. 151. 
Ethmoid Bone: outer surface of right lateral mass (enlarged). 
inf.Ttu.rbintited b. 
1 It also sometimes articulates with the superior maxilla. (See p. 152.) 
2 Dr. Humphry states that the crista galli is commonly inclined to one side, usually the opposite 
to that toward which the lower part of the perpendicular plate is bent {The Human Skeleton, 1858, 
p. 277). 182 
THE SKELETON. 
and is generally deflected a little to one side. Its anterior border articulates with 
the nasal spine of the frontal bone and crest of the nasal bones. Its posterior, 
divided into two parts, is connected by its upper half with the rostrum of the sphe- 
noid-by its lower half with the vomer. The inferior border serves for the attach- 
ment of the triangular cartilage of the nose. On each side of the perpendicular 
Fig. 152. 
Ethmoid at 
Perpendicular Plate of Ethmoid (enlarged), shown by removing the right lateral mass. 
plate numerous grooves and canals are seen leading from foramina on the cribri- 
form plate; they lodge filaments of the olfactory nerves. 
The Lateral Masses of the ethmoid consist of a number of thin-walled cellular 
cavities, the ethmoidal cells, interposed between two vertical plates of bone, the 
outer one of which forms part of the orbit, and the inner one part of the nasal 
fossa of the corresponding side. In the disarticulated bone many of these cells 
appear to be broken, but when the bones are articulated they are closed in at every 
part. The upper surface of each lateral mass presents a number of apparently half- 
broken cellular spaces; these are closed in when articulated by the edges of the 
ethmoidal notch of the frontal bone. Crossing this surface are two grooves on each 
side, converted into canals by articulation with the frontal; they are the anterior 
and posterior ethmoidal foramina, and open on the inner wall of the orbit. The 
posterior surface also presents large irregular cellular cavities, which are closed in 
by articulation with the sphenoidal turbinated bones and orbital process of the 
palate. The cells at the anterior surface are completed by the lachrymal bone and 
nasal process of the superior maxillary, and those below also by the superior maxil- 
lary. The outer surface of each lateral mass is formed of a thin, smooth square 
plate of bone called the os planum: it forms part of the inner wall of the orbit, 
and articulates above with the orbital plate of the frontal; below with the superior 
maxillary and orbital process of the palate; in front with the lachrymal; and 
behind with the sphenoid. 
From the inferior part of each lateral mass, immediately beneath the os planum, 
there projects downward and backward an irregular lamina of bone called the unci- 
form process, from its hook-like form: it serves to close in the upper part of the 
orifice of the antrum, and articulates with the ethmoidal process of the inferior 
turbinated bone. It is often broken in disarticulating the bones. 
The inner surface of each lateral mass forms part of the outer wall of the nasal 
fossa of the corresponding side. It is formed of a thin lamella of bone which 
descends from the under surface of the cribriform plate, and terminates below in a 
free convoluted margin, the middle turbinated bone. The whole of this surface is 
rough, and marked above by numerous grooves, which run nearly vertically downward THE ETHMOID BONE. 
183 
from the cribriform plate; they lodge branches of the olfactory nerve, which are dis- 
tributed on the mucous membrane covering the bone. The back part of this surface 
is subdivided by a narrow oblique fis- 
sure, the superior meatus of the nose, 
bounded above by a thin curved plate of 
bone-the superior turbinated bone. By 
means of an orifice at the upper part of 
this fissure the posterior ethmoidal cells 
open into the nose. Below, and in front 
of the superior meatus, is seen the con- 
vex surface of the middle turbinated bone. 
It extends along the whole length of the 
inner surface of each lateral mass; its 
lower margin is free and thick, and its 
concavity, directed outward, assists in 
forming the middle meatus. It is by a 
large orifice at the upper and front part 
of the middle meatus that the anterior ethmoidal cells, and through them the frontal 
sinuses, communicate with the nose by means of a funnel-shaped canal, the infundi- 
bulum. The cellular cavities of each lateral mass, thus walled in by the os planum 
on the outer side and by the other bones already mentioned, are divided by a thin 
transverse bony partition into two sets, which do not communicate with each other; 
they are termed the anterior and posterior ethmoidal cells or sinuses. The former, 
more numerous, communicate with the frontal sinuses above and the middle meatus 
below by means of a long flexuous cellular canal, the infundibulum ; the posterior, 
less numerous, open into the superior meatus, and communicate (occasionally) with 
the sphenoidal sinuses. 
Development.-By three centres-one for the perpendicular lamella and one 
for each lateral mass. 
The lateral masses are first developed, ossific granules making their first appear- 
ance in the os planum between the fourth and fifth months of foetal life, and extend- 
ing into the spongy bones. At birth the bone consists of the two lateral masses, which 
are small and ill developed. During the first year after birth the perpendicular and 
horizontal plates begin to ossify from a single nucleus, and become joined to the 
lateral masses about the beginning of the second year. The formation of the eth- 
moidal cells, which completes the bone, does not commence until about the fourth or 
fifth year. 
Articulations.-With fifteen bones: the sphenoid, two sphenoidal turbinated, 
the frontal, and eleven of the face-the two nasal, two superior maxillary, two lach- 
rymal, two palate, two inferior turbinated, and the vomer. No muscles are attached 
to this bone. 
Fig. 153. 
Ethmoid Bone, inner surface of right lateral mass 
(enlarged). 
DEVELOPMENT OF THE CRANIUM. 
The early stages of the development of the cranium have already been described (see p. 115). 
We have seen that it is formed from a layer of mesoblast, derived from the protovertebral plates 
of the trunk, which is spread over the whole surface of the rudimentary brain. That portion 
of this layer from which the bones of the skull are to be developed consists of a thin membran- 
ous capsule. 
Ossification commences in this, in the first place, in the roof, and is preceded by the deposi- 
tion of a membranous blastema upon the surface of the cerebral capsule, in which the ossifying 
process extends, the primitive membranous capsule becoming the internal periosteum and being 
ultimately blended with the dura mater. Although the bones of the vertex of the skull appear 
before those at the base, and make considerable progress in their growth, at birth ossification is 
more advanced in the base, this portion of the skull forming a solid, immovable groundwork. 184 
THE SKELETON. 
The Fontanelles (Figs. 154, 155). 
Before birth the bones at the vertex and side of the skull are separated from each other by 
membranous intervals in which bone is deficient. These intervals are principally found at the 
Fig. 154. 
Fig. 355. 
Skull at Birth, showing the anterior and 
posterior fontanelles. 
The Lateral Fontanelles. 
four angles of the parietal bones. In consequence of the wave of ossification being circular and 
the bones quadrilateral, the ossific matter first meets at the margins of the bones at the points 
nearest to their centres of ossification, and vacuities or spaces are left at the angles, which are 
called fontanelles, so named from the pulsations of the brain, which are perceptible at the ante- 
rior fontanelle, and were likened to the rising of water in a fountain. The anterior fontanelle is 
the largest, and corresponds to the junction of the sagittal and coronal sutures; the posterior 
fontanelle, of smaller size, is situated at the junction of the sagittal and lambdoid sutures; the 
remaining ones are situated at the inferior angles of the parietal bone. The latter are closed 
soon after birth; the two at the superior angles remain open longer, the posterior being closed 
in a few months after birth, the anterior remaining open until the first or second year. These 
spaces are gradually filled in by an extension of the ossifying process or by the development of a 
Wormian bone. Sometimes the anterior fontanelle remains open beyond two years, and is occa- 
sionally persistent throughout life. [Its persistence and enlargement are generally indicative of 
hydrocephalus.] 
Supernumerary or Wormian1 Bones. 
In addition to the constant centres of ossification of the skull, additional ones are occasion- 
ally found in the course of the sutures. These form irregular, isolated bones interposed between 
the cranial bones, and have been termed Wormian bones or ossa triquetra [z. e. triangular]. They 
are most frequently found in the course of the lambdoid suture, but occasionally also occupy the 
situation of the fontanelles, especially the posterior, and, more rarely, the anterior. Frequently 
one is found between the anterior inferior angle of the parietal bone and the greater wing of the 
sphenoid (the epipteric bone, Fig. 155). They have a great tendency to be symmetrical on the 
two sides of the skull, and they vary much in size, being in some cases not larger than a pin's 
head, and confined to the outer table; in other cases so large that one pair of these bones may 
form the whole of the occipital bone above the superior curved lines, as described by Beclard and 
Ward. Their number is generally limited to two or three, but more than a hundred have been 
found in the skull of an adult hydrocephalic skeleton. In their development, structure, and 
mode of articulation they resemble the other cranial bones. 
Congenital Fissures and Gaps. 
An arrest in the ossifying process may give rise to deficiencies or gaps, or to fissures, which 
are of importance in a medico-legal point of view, as they are liable to be mistaken for fractures. 
The fissures generally extend from the margins toward the centre of the bone, but the gaps may 
be found in the middle as well as at the edges. In course of time they may become covered with 
a thin lamina of bone. 
1 Wormius, a physician in Copenhagen, is said to have given the first detailed description of 
these bones. NASAL BONE. 
185 
BONES OF THE FACE. 
The facial bones are fourteen in number-viz. the 
Two Nasal, 
Two Superior Maxillary, 
Two Lachrymal, 
Two Malar, 
Two Palate, 
Two Inferior Turbinated, 
V omer, 
Inferior Maxillary. 
[Of these, the upper and lower jaws are the fundamental bones for mastication, 
and the others are accessories; for the chief function of the facial bones is to pro- 
vide an apparatus for mastication, while subsidiary functions are to provide for the 
sense-organs (eye, nose, tongue) and a vestibule to the respiratory and vocal organs. 
Hence the variations in the shape of the face in man and the lower animals depend 
chiefly on the question of the character of their food and their mode of obtaining it.] 
Nasal Bone. 
The Nasal (nasus, the nose) are two small oblong bones, varying in size and 
form in different individuals; they are placed side by side at the middle and upper 
part of the face, forming, by their junction, "the bridge" of the nose. Each bone 
presents for examination two surfaces and four borders. The outer surface is con- 
cave from above downward, convex from side to side; it is covered by the Pyramid- 
alis and Compressor nasi muscles, marked by numerous small arterial furrows, and 
perforated about its centre by a foramen, sometimes double, for the transmission of 
a small vein. Sometimes this foramen is absent on one or both sides, and occasion- 
ally the foramen caecum opens on its surface. The inner surface is concave from 
side to side, convex from above downward, in which direction it is traversed by a 
longitudinal groove (sometimes a canal) for the passage of a branch of the nasal 
nerve. The superior border is narrow, thick, and serrated for articulation with the 
nasal notch of the frontal bone. The inferior border is broad, thin, sharp, directed 
obliquely downward, outward, and backward, and serves for the attachment of the 
Fig. 156. 
Fig. 157. 
with Frontal B. 
unth 
Fro nt al tfjnne- 
'with 
-Opposite bone. 
cresfi 
with 
TpendieulaT 
/jPlate nfEtJimoul, 
groove for nasal nemc- 
Inner Surface 
Outer Surface,. 
lateral cartilage of the nose. This border presents, about its middle, a notch through 
which passes the branch of the nasal nerve above referred to, and is prolonged at its 
inner extremity into a sharp spine, which, when articulated with the opposite bone, 
forms the nasal angle. The external border is serrated, bevelled, at the expense of 
the internal surface above and of the external below, to articulate with the nasal 
process of the superior maxillary. The internal border, thicker above than below, 
articulates with its fellow of the opposite side, and is prolonged behind into a verti- 
cal crest, which forms part of the septum of the nose: this crest articulates with the 
nasal spine of the frontal above and the perpendicular plate of the ethmoid below. 
Development.-By one centre for each bone, which appears about the same 
period as in the vertebrae. 
Right Nasal Bone. 
Left Nasal Bone. 186 
THE SKELETON. 
Articulations.-With four bones : two of the cranium, the frontal and ethmoid, 
and two of the face, the opposite nasal and the superior maxillary. 
No muscles are directly attached to this bone. 
Superior Maxillary Bone. 
The Superior Maxillary (maxilla, the jaw-bone) is one of the most important 
bones of the face in a surgical point of view, on account of the number of diseases 
to which some of its parts are liable. Its minute examination becomes, therefore, 
a matter of considerable interest. It is the largest bone of the face, excepting the 
lower jaw, and forms, by its union with its fellow of the opposite side, the whole 
of the upper jaw. Each bone assists in the formation of three cavities-the roof 
of the mouth, the floor and outer wall of the nasal fossae, and the floor of the orbit 
-and also enters into the formation of two fossae, the zygomatic and spheno-maxil- 
lary, and two fissures, the spheno-maxillary and pterygo-maxillary. 
The bone presents for examination a body and four processes-malar, nasal, alve- 
olar, and palatine. 
The body is somewhat cuboid, and is hollowed out in its interior to form a large 
cavity, the antrum of Highmore. Its surfaces are four-an external or facial, a 
posterior or zygomatic, a superior or orbital, and an internal. 
The external or facial surface (Fig. 158) is directed forward and outward. Just 
above the incisor teeth is a depression, the incisive or myrtiform fossa, which gives 
Fig. 158. 
Outer Surface. 
Lachrymal tubercle. 
TENDO OCULt-4 
-PosteriorMental- Canals 
Incisive fossa- 
Ma.Killa.ry Tuberosity. 
Left Superior Maxillary Bone, outer surface. 
origin to the Depressor alae nasi, and below it, to the alveolar border, is attached a 
slip of the Orbicularis oris. Above and a little external to it the Compressor nasi 
arises. More external is another depression, the canine fossa, larger and deeper 
than the incisive fossa, from which it is separated by a vertical ridge, the canine 
eminence, corresponding to the socket of the canine tooth. The canine fossa gives 
origin to the Levator anguli oris. Above the canine fossa is the infraorbital fora- SUPERIOR MAXILLARY BONE. 
187 
men, the termination of the infraorbital canal; it transmits the infraorbital nerve 
and artery. Above the infraorbital foramen is the margin of the orbit, which 
affords partial attachment to the Levator labii superioris proprius. To the sharp 
margin of bone which bounds this surface in front and separates it from the inter- 
nal surface is attached the Dilator naris posterior. 
The posterior or zygomatic surface is convex, directed backward and out- 
ward, and forms part of the zygomatic fossa. It presents about its centre several 
apertures leading to canals in the substance of the bone; they are termed the pos- 
terior dental canals, and transmit the posterior dental vessels and nerves. At the 
lower part of this surface is a rounded eminence, the maxillary tuberosity, especially 
prominent after the growth of the wisdom tooth, rough on its inner side for articula- 
tion with the tuberosity of the palate bone, and sometimes with the external ptery- 
goid plate. It gives attachment to a few fibres of origin of the internal pterygoid 
muscle. Immediately above the rough surface is a groove, which, running obliquely 
down on the inner surface of the bone, is converted into a canal by articulation with 
the palate bone, forming the posterior palatine canal. 
The superior or orbital surface is thin, smooth, triangular, and forms part of 
the floor of the orbit. It is bounded internally by an irregular margin which artic- 
ulates, in front, with the lachrymal; in the middle, with the os planum of the eth- 
moid ; behind, with the orbital process of the palate bone ; bounded externally by a 
smooth rounded edge which enters into the formation of the spheno-maxillary fissure, 
and which sometimes articulates at its anterior extremity with the orbital plate of the 
sphenoid; bounded in front by part of the circumference of the orbit, which is con- 
tinuous on the inner side with the nasal, on the outer side with the malar, process. 
Along the middle line of the orbital surface is a deep groove, the infraorbital, for 
the passage of the infraorbital nerve and artery. This groove commences at the 
middle of the outer border of the surface, and, passing forward, terminates in a 
canal which subdivides into two branches; one of the canals, the infraorbital, opens 
just below the margin of the orbit; the other, which is smaller, runs into the sub- 
stance of the anterior wall of the antrum; it is called the anterior dental canal, 
transmitting the anterior dental vessels and nerve to the front teeth of the upper 
jaw. At the inner and fore part of the orbital surface, just external to the lach- 
rymal canal, is a minute depression which gives origin to the Inferior oblique 
muscle of the eye. 
The internal surface (Fig. 159) is unequally divided into two parts by a hori- 
zontal projection of bone, the palate process ; the portion above the palate process 
forms part of the outer wall of the nasal fossae; that below it forms part of the 
cavity of the mouth. The superior division of this surface presents a large irreg- 
ular opening leading into the antrum of Highmore. At the upper border of this 
aperture are numerous broken cellular cavities which, in the articulated skull, are 
closed in by the ethmoid and lachrymal bones. Below the aperture is a smooth 
concavity which forms part of the inferior meatus of the nasal fossae, and behind it 
is a rough surface which articulates with the perpendicular plate of the palate bone, 
traversed by a groove which, commencing near the middle of the posterior border, 
runs obliquely downward and forward, and forms, when completed by its articula- 
tion with the palate bone, the posterior palatine canal. In front of the opening of 
the antrum is a deep groove, converted into a canal by the lachrymal and inferior 
turbinated bones, which is coated with mucous membrane and called the lachrymal 
or nasal duct. More anteriorly is a well-marked rough ridge, the inferior turbi- 
nated crest, for articulation with the inferior turbinated bone. The concavity above 
this, ridge forms part of the middle meatus of the nose, whilst that below it forms 
part of the inferior meatus. The portion of this surface below the palate process is 
concave, rough, and uneven, and perforated by numerous small foramina for the 
passage of nutrient vessels. It enters into the formation of the roof of the mouth. 
The Antrum of Highmore, or Maxillary Sinus, is a large triangular-shaped 
cavity hollowed out of the body of the maxillary bone; its apex, directed out- 
ward, is formed by the malar process; its base, by the outer wall of the nose. Its 188 
THE SKELETON. 
walls are everywhere exceedingly thin, its roof being formed by the orbital plate, 
its floor by the alveolar process, its anterior wall by the facial, and its posterior by 
the zygomatic surface. Its inner wall, or base, presents, in the disarticulated bone, 
a large irregular aperture which communicates with the nasal fossa. The margins 
of this aperture are thin and ragged, and the aperture itself is much contracted by 
Fig. 159. 
Hones partoaiHy closing Orifice of Antram 
marked in oatE/ee 
Ethmoid 
Inferior Turbinated 
Palate" 
Ant. Nasal Spine 
Bristle 
passed through 
Ant.pailat. Canal 
Left Superior Maxillary Bone, inner surface. 
its articulation with the ethmoid above, the inferior turbinated below, and the palate 
bone behind.1 In the articulated skull this cavity communicates with the middle 
meatus of the nasal fossae, generally by two small apertures left between the above- 
mentioned bones. In the recent state usually only one small opening exists, near 
the upper part of the cavity, sufficiently large to admit the end of a probe, the other 
being closed by the lining membrane of the sinus. 
Crossing the cavity of the antrum are often seen several projecting laminae of 
bone similar to those seen in the sinuses of the cranium; and on its posterior wall 
are the jMstow dental canals, transmitting the posterior dental vessels and nerves 
to the teeth. Projecting into the floor are several conical processes, corresponding 
to the roots of the first and second molar teeth ;2 in some cases the floor is perfo- 
rated by the teeth in this situation. It is from the extreme thinness of the walls 
of this cavity that we are enabled to explain how a tumor growing from the antrum 
encroaches upon the adjacent parts, pushing up the floor of the orbit and displacing 
the eyeball, projecting inward into the nose, protruding forward on to the cheek, 
and making its way backward into the zygomatic fossa and downward into the 
mouth. [The cavity of the antrum is so large that percussion will often give 
important information as to whether the antrum be empty or full. It can be 
1 In some cases, at any rate, the lachrymal bone encroaches slightly on the anterior superior por- 
tion of the opening, and assists in forming the inner wall of the antrum. 
2 The number of teeth whose fangs are in relation with the floor of the antrum is variable. The 
antrum " may extend so as to be in relation to all the teeth of the true maxilla, from the canine to 
the dens sapientice." (See Mr. Salter on "Abscess of the Antrum," in a System of Surgery, edited by 
T. Holmes, 2d ed., vol. iv. p. 356.) SUPERIOR MAXILLARY BONE. 
189 
perforated either through the anterior wall on either side of the first or second 
molar, or, if a suitable tooth be carious, through its socket after its removal.1] 
The Malar Process is a rough triangular eminence situated at the angle of 
separation of the facial from the zygomatic surface. In front it is concave, forming 
part of the facial surface; behind, it is also concave, and forms part of the zygo- 
matic fossa; above, it is rough and serrated for articulation with the malar bone, 
whilst below a prominent ridge marks the division between the facial and zygo- 
matic surfaces. A small part of the Masseter muscle arises from this process. 
The Nasal Process is a thick triangular plate of bone which projects upward, 
inward, and backward by the side of the nose, forming part of its lateral boundary. 
Its external surface is concave, smooth, perforated by numerous foramina, and gives 
attachment to the Levator labii superioris alaeque nasi, the Orbicularis palpebrarum, 
and the Tendo oculi. Its internal surface forms part of the outer wall of the nose; 
it articulates above with the frontal, and presents a rough, uneven surface which 
articulates with the ethmoid bone, closing in the anterior ethmoidal cells; below 
this is a transverse ridge, the superior turbinated crest, for articulation with the 
middle turbinated bone of the ethmoid, bounded below by a smooth concavity which 
forms part of the middle meatus; below this, again, is the inferior turbinated crest 
(already described), for articulation with the inferior turbinated bone; and, still 
more inferiorly, the concavity which forms part of the inferior meatus. The 
anterior border of the nasal process is thin, directed obliquely downward and 
forward, and presents a serrated edge, for articulation with the nasal bone; its 
posterior border is thick, and hollowed into a groove for the lachrymal duct: of 
the two margins of this groove, the innei' one articulates with the lachrymal bone, 
the outer one forms part of the circumference of the orbit. Just where the latter 
joins the orbital surface is a small tubercle, the lachrymal tubercle ; this used to be 
taken as a guide in the performance of the operation for fistula lachrymalis. The 
lachrymal groove in the articulated skull is converted into a canal by the lachrymal 
bone and lachrymal process of the inferior turbinated; it is directed downward and 
a little backward and outward, is about the diameter of a goose-quill, slightly nar- 
rower in the middle than at either extremity, and terminates below in the inferior 
meatus. It lodges the lachrymal duct. 
The Alveolar Process is the thickest and most spongy part of the bone, broader 
behind than in front, and excavated into deep cavities for the reception of the teeth. 
These cavities are eight in number, and vary in size and depth according to the 
teeth they contain. That for the canine tooth is the deepest; those for the molars 
are the widest, and subdivided into minor cavities; those for the incisors are single, 
but deep and narrow. The Buccinator muscle arises from the outer surface of this 
process as far forward as the first molar tooth. [After the loss of the permanent 
teeth at any time, but especially in old age, the alveolar process of the upper jaw 
(Fig. 176, p. 202), like that of the lower, is absorbed. In old age also the entire 
bone thins greatly, and often the palate process and other parts become a mere 
shell-a point to be remembered in operations on old people.] 
The Palate Process, thick and strong, projects horizontally inward from the 
inner surface of the bone. It is much thicker in front than behind, and forms a 
considerable part of the floor of the nostril and the roof of the mouth. 
Its inferior surface (Fig. 160) is concave, rough, and uneven, and forms part of 
the roof of the mouth. This surface is perforated by numerous foramina for the 
passage of the nutrient vessels, channelled at the back part of its alveolar border by 
a longitudinal groove, sometimes a canal, for the transmission of the posterior pala- 
tine vessels and the anterior and external palatine nerves from Meckel's ganglion, and 
presents little depressions for the lodgment of the palatine glands. When the two 
superior maxillary bones are articulated together, a large orifice may be seen in the 
middle line immediately behind the incisor teeth. This is the anterior palatine canal 
or fossa. This canal, as it passes through the thickness of the palate process, is divided 
1 See a paper by the American Editor on " Percussion of the Frontal and Maxillary Sinuses," in 
the Medical News for Aug. 16, 1884. 190 
THE SKELETON. 
into four compartments; that is to say, two canals branch off laterally to the right 
and left nasal fossae, and two canals, one in front and one behind, lie in the middle 
line. The former pair of these canals are named the foramina of Stenson, and through 
them pass the anterior or terminal 
branch of the descending or poste- 
rior palatine arteries which ascends 
from the mouth to the nasal fossae. 
The remaining pair of canals are 
termed the foramina of Scarpa, and 
transmit the naso-palatine nerves, 
the left passing through the anterior 
and the right through the posterior 
canal. On the palatal surface of the 
process a delicate linear suture may 
sometimes be seen extending from 
the anterior palatine fossa to the in- 
terval between the lateral incisor and 
the canine tooth. This marks out 
the intermaxillary or incisive bone, 
which in some animals exists per- 
manently as a separate piece. It 
includes the whole thickness of the 
alveolus, the corresponding part of 
the floor of the nose, and the ante- 
rior nasal spine, and contains the 
sockets of the incisor teeth. The 
upper surface is concave from side 
to side, smooth, and forms part of 
the floor of the nose. It presents 
the upper orifices of the foramina 
of Stenson and Scarpa, the former 
being on each side of the middle line, the latter being situated in the intermaxillary 
suture, and therefore not visible unless the two bones are placed in apposition. The 
outer border of the palate process is incorporated with the 
rest of the bone. The inner border is thicker in front than 
behind, and is raised above into a ridge, which, with the cor- 
responding ridge in the opposite bone, forms a groove for the 
reception of the vomer. The anterior margin is bounded by 
the thin concave border of the opening of the nose, prolonged 
forward internally into a sharp process, forming, with a simi- 
lar process of the opposite bone, the anterior nasal spine. 
The posterior border is serrated for articulation with the 
horizontal plate of the palate-bone. 
Development.-This bone is formed at such an early 
period, and ossification proceeds in it with such rapidity, 
that it has been found impracticable hitherto to determine 
with accuracy its number of centres. It appears, how- 
ever, probable that it has four centres of development- 
viz. (1) the premaxilla, in which the incisive portion of 
the alveolar arch is formed: this part is of cartilaginous 
origin, and is developed in the anterior extremity of 
the ethmo-vomerine plate; (2) the prepalatine portion, 
comprising the palate plate and a considerable portion of 
the inner wall of the antrum; (3) the maxillary portion, 
including all the facial and orbital parts of the bone inter- 
nal to the infraorbital canal; (4) the malar portion, which comprises that portion of 
the bone external to the infraorbital canal. The premaxillary portion is indicated 
Fig. 160. 
.Arrt.palatine 
Canal 
Foramen 
of 
Foramen 
of Scarpa 
Post. peel aline Lanai 
.Accessory palatine. 
foramen' 
The Palate and Alveolar Arch. 
Fig.161. 
Anterior Surface. 
Inferior Surface. 
Development of Superior 
Maxillary Bone at Birth. THE LACHRYMAL BONE. 
191 
in young bones by a fissure which marks off a small segment of the palate, including 
the two incisor teeth. In some animals this remains permanently as a separate piece, 
constituting the premaxillary bone; and in the human subject where the jaw is mal- 
formed, as in cleft palate, this segment may be separated from the maxillary bone by 
a deep fissure extending backward between the two into the palate. If the fissure 
be on both sides, both segments are quite isolated from the maxillary bones, and 
hang from the end of the vomer; they are not unfrequently much displaced, and the 
deformity is often accompanied by congenital fissure of the upper lip either on one 
or both sides of the median line. The maxillary sinus [antrum] appears at an ear- 
lier period than any of the other nasal sinuses, its development commencing about 
the fourth month of foetal life. The sockets for the teeth are formed by the growing 
downward of two plates from the dental groove, which subsequently becomes divided 
by partitions jutting across from the one to the other. 
Articulations.-With nine bones : two of the cranium-the frontal and ethmoid; 
and seven of the face-viz. the nasal, malar, lachrymal, inferior turbinated, palate, 
vomer, and its fellow of the opposite side. Sometimes it articulates with the orbital 
plate of the sphenoid. 
Attachment of Muscles.-To twelve: the Orbicularis palpebrarum, Obliquus 
inferior oculi, Levator labii superioris almque nasi, Levator labii superioris proprius, 
Levator anguli oris, Compressor nasi, Depressor alm nasi, Dilatator naris posterior. 
Masseter, Buccinator, Internal pterygoid, and Orbicularis oris. 
The Lachrymal Bone. 
The Lachrymal (lachryma, a tear) are the smallest and most fragile bones of the 
face. They are situated at the front part of the innei' wall of the orbit, and resem- 
ble somewhat in form, thinness, and size a finger-nail; hence 
they are termed the ossa unguis. Each bone presents for 
examination two surfaces and four borders. The external or 
orbital surface (Fig. 162) is divided by a vertical ridge, the 
lachrymal crest, into two parts. The portion of bone in front 
of this ridge presents a smooth, concave, longitudinal groove, 
the free margin of which unites with the nasal process of the 
superior maxillary bone, completing the lachrymal groove. 
The upper part of this groove lodges the lachrymal sac; the 
lower part assists in the formation of the lachrymal canal and 
lodges the nasal duct. The portion of bone behind the ridge 
is smooth, slightly concave, and forms part of the inner wall 
of the orbit. The ridge, with a part of the orbital surface 
immediately behind it, affords attachment to the Tensor tarsi: 
the ridge terminates below in a small hook-like process, which 
articulates with the lachrymal tubercle of the superior maxil- 
lary bone and completes the upper orifice of the lachrymal 
canal. It sometimes exists as a separate piece, which is then called the lesser lach- 
rymal bone. The internal or nasal surface presents a depressed furrow, correspond- 
ing to the ridge on its outer surface. The surface of bone in front of this forms 
part of the middle meatus, and that behind it articulates with the ethmoid bone, 
filling in the anterior ethmoidal cells. Of the four borders, the anterior is the 
longest and articulates with the nasal process of the superior maxillary bone. The 
posterior, thin and uneven, articulates with the os planum of the ethmoid. The 
superior, the shortest and thickest, articulates with the internal angular process of 
the frontal bone. The inferior is divided by the lower edge of the vertical crest 
into two parts; the posterior part articulates with the orbital plate of the superior 
maxillary bone; the anterior portion is prolonged downward into a pointed process 
which articulates with the lachrymal process of the inferior turbinated bone and 
assists in the formation of the lachrymal canal. 
Fig. 162. 
Frontal 
Left Lachrymal Bone, ex- 
ternal surface (slightly 
enlarged). 192 
THE SKELETON. 
Development.-By a single centra, which makes its appearance soon after ossifi- 
cation of the vertebrae has commenced. 
Articulations.-With four bones : two of the cranium, the frontal and ethmoid, 
and two of the face, the superior maxillary and the inferior turbinated. 
Attachment of Muscles.-To one muscle, the Tensor tarsi. 
The Malar Bone. 
The Malar (mala, the cheek) are two small quadrangular bones situated at the 
upper and outer part of the face: they form the prominence of the cheek, part of 
the outer wall and floor of the orbit, and part of the temporal and zygomatic fossae. 
Each bone presents for examination an external and an internal surface; four pro- 
cesses, the frontal, orbital, maxillary, and zygomatic; and four borders. 
The external surface (Fig. 163) is smooth, convex, perforated near its centre 
by one or two small apertures, the malar foramina, for the passage of nerves and 
vessels, covered by the Orbicularis palpebrarum muscle, and affords attachment to 
the Zygomaticus major and minor muscles. 
Fig. 163. 
Fig. 164. 
Brindes passed through, 
Tempore-Malar Ca-nals 
Left Malar Bone, outer surface. 
Left Malar Bone, inner surface. 
The internal surface (Fig. 164), directed backward and inward, is concave, 
presenting internally a rough triangular surface for articulation with the superior 
maxillary bone; and externally a smooth concave surface which forms the 
anterior boundary of the temporal fossa above, and below, where it is wider, 
forms part of the zygomatic fossa. This surface presents, a little above its 
centre, the aperture of one or two malar canals, and affords attachment to part 
of two muscles, the Temporal above and the Masseter below. Of the four pro- 
cesses, the frontal is thick and serrated, and articulates with the external angular 
process of the frontal bone. The orbital process is a thick and strong plate which 
projects backward from the orbital margin of the bone. Its upper surface, smooth 
and concave, forms, by its junction with the great ala of the sphenoid, the outer 
wall of the orbit. Its under surface, smooth and convex, forms part of the tem- 
poral fossa. Its anterior margin is smooth and rounded, forming part of the circum- 
ference of the orbit. Its superior margin, rough and directed horizontally, articu- 
lates with the frontal bone behind the external angular process. Its posterior margin 
is rough and serrated, for articulation with the sphenoid; internally it is also ser- 
rated, for articulation with the orbital surface of the superior maxillary. At the 
angle of junction of the sphenoidal and maxillary portions a short rounded non- 
articular margin is generally seen; this forms the anterior boundary of the spheno- 
maxillary fissure ; occasionally no such non-articular margin exists, the fissure being 
completed by the direct junction of the maxillary and sphenoid bones or by the THE PALATE BONE. 
193 
interposition of a small Wormian bone in the angular interval between them. On 
the upper surface of the orbital process are seen the orifices of one or two temporo- 
malar canals; one of these usually opens on the posterior surface, the other (occa- 
sionally two) on the facial surface: they transmit filaments (temporo-malar) of the 
orbital branch of the superior maxillary nerve. The maxillary process is a rough 
triangular surface which articulates with the superior maxillary bone. The zygo- 
matic process, long, narrow, and serrated, articulates with the zygomatic process of 
the temporal bone. Of the four borders, the antero-superior or orbital is smooth, 
arched, and forms a considerable part of the circumference of the orbit. The antero- 
inferior or maxillary border is rough, and bevelled at the expense of its inner table 
to articulate with the superior maxillary bone, affording attachment by its outer 
margin to the Levator labii superioris proprius just at its point of junction with the 
superior maxillary. The postero-superior or temporal border, curved like an italic 
letter/, is continuous above with the commencement of the temporal ridge; below, 
with the upper border of the zygomatic arch : it affords attachment to the temporal 
fascia. The poster o-inferior, or zygomatic, is continuous with the lower border of 
the zygomatic arch, affording attachment by its rough edge to the Masseter muscle. 
Development.-By a single centre of ossification, which appears at about the 
same period when ossification of the vertebrae commences.1 
Articulations.-With four bones: three of the cranium, frontal, sphenoid, and 
temporal; and one of the face, the superior maxillary. 
Attachment of Muscles.-To five: the Levator labii superioris proprius, Zygo- 
maticus major and minor, Masseter, and Temporal. 
The Palate Bone. 
The Palate Bones (palatum, the palate) are situated at the back part of the 
nasal fossae: they are wedged in between the superior maxillary and the pterygoid 
process of the sphenoid. Each bone assists in the formation of three cavities-the 
floor and outer wall of the nose, the roof of the mouth, and the floor of the orbit- 
and enters into the formation of two fossae, the spheno-maxillary and pterygoid; 
and one fissure, the spheno-maxillary. In form the palate bone somewhat resem- 
bles the letter L, and may be divided into an inferior or horizontal plate and a 
superior or vertical plate. 
The Horizontal Plate is thick, of a quadrilateral form, and presents two sur- 
faces and four borders. The superior surface, concave from side to side, forms the 
back part of the floor of the nostril. The inferior surface, slightly concave and 
rough, forms the back part of the hard palate. At its posterior part may be seen 
a transverse ridge, more or less marked, for the attachment of the aponeurosis of the 
Tensor palati muscle. At the outer extremity of this ridge is a deep groove con- 
verted into a canal by its articulation with the tuberosity of the superior maxillary 
bone, and forming the posterior palatine canal. Near this groove the orifices of 
one or two small canals, accessory posterior palatine, may frequently be seen. The 
anterior border is serrated, bevelled at the expense of its inferior surface, and articu- 
lates with the palate process of the superior maxillary bone. The posterior border 
is concave, free, and serves for the attachment of the soft palate. Its inner extrem- 
ity is sharp and pointed, and, when united with the opposite bone, forms a projecting 
process, the posterior nasal spine, for the attachment of the Azygos uvulae. The 
external border is united with the lower part of the perpendicular plate almost at 
right angles. The internal border, the thickest, is serrated for articulation with its 
fellow of the opposite side; its superior edge is raised into a ridge which, united 
with the opposite bone, forms a crest in which the vomer is received. 
1 In some Quadrumana the malar bone consists of two parts, an orbital and a malar, and is ossified 
by two centres. In the embryo these parts have been observed to be separated, and even after birth 
the malar bone is sometimes divided by a horizontal suture into an upper and larger division and a 
lower and smaller. It is possible, therefore, that this bone is ossified sometimes by two centres, one 
for the orbital and the other for the malar portion. 194 
THE SKELETON. 
The Vertical Plate (Fig. 165) is thin, of an oblong form, and directed upward 
and a little inward. It presents two surfaces, an external and an internal, and four 
borders. 
The internal surface presents at its lower part a broad, shallow depression 
which forms part of the inferior meatus of the nose. Immediately above this is a 
■well-marked horizontal ridge, the inferior turbinated crest, for articulation with the 
inferior turbinated bone; 
above this, a second broad 
shallow depression, which 
forms part of the middle 
meatus, surmounted above 
by a horizonal ridge less 
prominent than the inferior, 
the superior turbinated crest, 
for articulation with the mid- 
dle turbinated bone. Above 
the superior turbinated crest 
is a narrow horizontal groove 
which forms part of the supe- 
rior meatus. 
The external surface is 
rough and irregular through- 
out the greater part of its ex- 
tent, for articulation with the 
inner surface of the superior 
maxillary bone, its upper and 
back part being smooth where 
it enters into the formation of 
thespheno-maxillary fossa; it 
is also smooth in front, where 
it covers the orifice of the antrum. Toward the back part of this surface is a deep 
groove, converted into a canal, the posterior palatine, by its articulation with the 
superior maxillary bone. It transmits the 
posterior or descending palatine vessels, and 
two of the descending palatine branches from 
Meckel's ganglion. 
The anterior border is thin, irregular, 
and presents opposite the inferior turbi- 
nated crest a pointed projecting lamina, 
the maxillary process, which is directed 
forward and closes in the lower and back 
part of the opening of the antrum. The 
posterior border (Fig. 166) presents a deep 
groove, the edges of which are serrated for 
articulation with the pterygoid process of 
the sphenoid. At the lower part of this 
border is seen a pyramidal process of bone, 
the pterygoid process, or tuberosity of the 
palate, which is received into the angular 
interval between the two pterygoid plates 
of the sphenoid at their inferior extremity. 
This process presents at its back part three 
grooves, a median and two lateral ones. The 
former is smooth, and forms part of the 
pterygoid fossa, affording attachment to the 
Internal pterygoid muscle; whilst the lateral grooves are rough and uneven, for 
articulation with the anterior border of each pterygoid plate. A few fibres of the 
Fig. 165. 
Maxi.lla.ry 
Surface 
Superior Mca,tu,s__ 
Ttilati.n&Foranictb- 
VERTICAL PLATT 
Maxillary 
' Process 
Left Palate Bone, internal view (enlarged). 
HORIZONTAL PLATE 
Fig. 166. 
Sjxhvno. jivclntiric> For. 
VERTICAL PLATE 
S/ihe-noLtlal /irocess. 
-A-rticuCur hort. _ 
' Ext. Surf 
■JY 071~ arLicuLu'rfort. 
Tost trior 
Jiuln/'inc 
CuimI 
\ Puit . 
.Piucsul Sjxinc 
F AZYCOS UVULfc 
HORIZONTA L 
PLATE 
Left Palate Bone, posterior view (enlarged). THE PALATE BONE. 
195 
Superior constrictor also arise from the tuberosity of the palate bone. The base of 
this process, continuous with the horizontal portion of the bone, presents the aper- 
tures of the accessory descending palatine canals, through which passes the poste- 
rior of the three descending branches of Meckel's ganglion, whilst its outer surface 
is rough, for articulation with the inner surface of the body of the superior maxil- 
lary bone. 
The superior border of the vertical plate presents two well-marked processes 
separated by an intervening notch or foramen. The anterior, or larger, is called 
the orbital process; the posterior, the sphenoidal. 
The Orbital Process, directed upward and outward, is placed on a higher level 
than the sphenoidal. It presents five surfaces, which enclose a hollow cellular cav- 
ity, and is connected to the perpendicular plate by a narrow constricted neck. Of 
these five surfaces, three are articular, two non-articular or free surfaces. The three 
articular are as follows: The anterior or maxillary surface, which is directed forward, 
outward, and downward, is of an oblong form, and rough for articulation with the 
superior maxillary bone. The posterior or sphenoidal surface is directed backward, 
upward, and inward. It ordinarily presents a small open cell, which communicates 
with the sphenoidal sinus, and the margins of which are serrated for articulation 
with the vertical part of the sphenoidal turbinated bone. The internal or ethmoidal 
surface is directed inward, upward, and forward, and articulates with the lateral mass 
of the ethmoid bone. In some cases the cellular cavity above mentioned opens on 
this surface of the bone; it then communicates with the posterior ethmoidal cells. 
More rarely it opens on both surfaces, and then communicates both with the 
posterior ethmoidal cells and the sphenoidal sinus. The non-articular or free 
surfaces are the superior or orbital, directed upward and outward, of triangular 
form, concave, smooth, and forming the back part of the floor of the orbit; 
and the external or zygomatic surface, directed outward, backward, and down- 
ward, of an oblong form, smooth, lying in the spheno-maxillary fossa, and looking 
into the zygomatic fossa. The latter surface is separated from the orbital by a 
smooth rounded border which enters into the formation of the spheno-maxillary 
fissure. 
The Sphenoidal Process of the palate bone is a thin compressed plate, much 
smaller than the orbital, and directed upward and inward. It presents three sur- 
faces and two borders. The superior surface, the smallest of the three, articulates 
with the horizontal part of the sphenoidal turbinated bone; it presents a groove 
which contributes to the formation of the pterygo-palatine canal. The internal 
surface is concave, and forms part of the outer wall of the nasal fossa. The 
external surface is divided into an articular and a non-articular portion ; the former 
is rough, for articulation with the inner surface of the pterygoid process of the 
sphenoid; the latter is smooth, and forms part of the spheno-maxillary fossa. The 
anterior border forms the posterior boundary of the spheno-palatine foramen. The 
posterior border, serrated at the expense of the outer table, articulates with the 
inner surface of the pterygoid process. 
The orbital and sphenoidal processes are separated from each other by a deep 
notch, which is converted into a foramen, the spheno-palatine, by articulation with 
the sphenoidal turbinated bone. Sometimes the two processes are united above, 
and form between them a complete foramina, or the notch is crossed by one or 
more spiculse of bone, so as to form two or more foramina. In the articulated 
skull this foramen opens into the back part of the outer wall of the superior 
meatus, and transmits the spheno-palatine vessels and the superior nasal and 
naso-palatine nerves. 
Development.-From a single centre, which makes its appearance about the 
second month at the angle of junction of the two plates of the bone. From this 
point ossification spreads inward to the horizontal plate, downward into the tuber- 
osity, and upward into the vertical plate. In the foetus the horizontal plate is much 
longer than the vertical, and even after it is fully ossified the whole bone is at first 
remarkable for its shortness. 196 
THE SKELETON. 
Articulations.-With six bones:, the sphenoid, ethmoid, superior maxillary, 
inferior turbinated, vomer, and opposite palate. 
Attachment of Muscles.-To five : the Tensor palati, Azygos uvulae, Internal 
and External pterygoid, and Superior constrictor of the pharynx. 
The Inferior Turbinated Bones. 
The Inferior Turbinated Bones (turbo, a whirl) are situated one on each side 
of the outer wall of the nasal fossae. Each consists of a layer of thin spongy bone 
curled upon itself like a scroll, hence its name "turbinated," and extends horizon- 
tally along the outer wall of the nasal fossa immediately below the orifice of the 
antrum. Each bone presents two surfaces, two borders, and two extremities. 
The internal surface (Fig. 167) is convex, perforated by numerous apertures, 
and traversed by longitudinal grooves and canals for the lodgment of arteries and 
veins. In the recent state it is covered by the lining membrane of the nose. 
Fig. 167. 
Fig. 168. 
Right Inferior Turbinated Bone, internal surface. 
Right Inferior Turbinated Bone, outer surface. 
The external surface is concave (Fig 168), and forms part of the inferior mea- 
tus. Its upper border is thin, irregular, and connected to various bones along the 
outer wall of the nose. It may be divided into three portions : of these, the anterior 
articulates with the inferior turbinated crest of the superior maxillary bone; the 
posterior, with the inferior turbinated crest of the palate bone; the middle portion 
of the superior border presents three well-marked processes, which vary much in 
their size and form. Of these, the anterior and smallest is situated at the junction 
of the anterior fourth with the posterior three-fourths of the bone; it is small and 
pointed, and is called the lachrymal process, for it articulates with the anterior 
inferior angle of the lachrymal bone, and by its margins with the groove on the 
back of the nasal process of the superior maxillary, and thus assists in forming the 
lachrymal canal. At the junction of the two middle fourths of the bone, but 
encroaching on its posterior fourth, a broad thin plate, the ethmoidal process, 
ascends to join the unciform process of the ethmoid: from the lower border of 
this process a thin lamina of bone curves downward and outward, hooking over the 
lower edge of the orifice of the antrum, which it narrows below: it is called the 
maxillary process, and fixes the bone firmly on to the outer wall of the nasal fossa. 
The inferior border is free, thick, and cellular in structure, more especially in the 
middle of the bone. Both extremities are more or less narrow and pointed. If the 
bone is held so that its outer concave surface is directed backward (?. e. toward the 
holder), and its superior border, from which the lachrymal and ethmoidal processes 
project, upward, the lachrymal process will be directed to the side to which the 
bone belongs.1 
Development.-By a single centre, which makes its appearance about the 
middle of foetal life. 
Articulations.-With four bones: one of the cranium, the ethmoid; and three 
of the face, the superior maxillary, lachrymal, and palate. 
No muscles are attached to this bone. 
1 If the lachrymal process is broken off, as is often the case, the side to which the bone belongs 
may be known by recollecting that the maxillary process is nearer the back than the front of the 
bone. THE VOMER. 
197 
The Vomer. 
The Vomer (vomer, a ploughshare) is a single bone situated vertically at the 
back part of the nasal fossae, forming part of the septum of the nose. It is thin, 
somewhat like a ploughshare in form; but it varies in different individuals, being 
frequently bent to one or the other side; it presents for examination two surfaces 
and four borders. The lateral surfaces are smooth, marked by small furrows for 
the lodgment of blood-vessels, 
and by a groove on each side, 
sometimes a canal, the naso- 
palatine, which runs obliquely 
downward and forward to the 
intermaxillary suture [foramina 
of Scarpa in the anterior pala- 
tine fossa]; it transmits the 
naso-palatine nerve. The su- 
perior border, the thickest, 
presents a deep groove, bound- 
ed on each side by a horizontal 
projecting ala of bone; the 
groove receives the rostrum 
of the sphenoid, whilst the 
alae are overlapped and re- 
tained by laminae (the vaginal 
processes) which project from 
the under surface of the body 
of the sphenoid at the base of the pterygoid processes. At the front of the groove 
a fissure is left for the transmission of blood-vessels to the substance of the bone. 
The inferior border, the longest, is broad and uneven in front, where it articulates 
with the two superior maxillary bones; thin and sharp behind, where it joins with 
the palate bones. The upper half of the anterior border usually consists of two 
laminae of bone, between which is received the perpendicular plate of the ethmoid, 
the lower half consisting of a single rough edge, also occasionally channelled, which 
is united to the triangular cartilage of the nose. The posterior border is free, con- 
cave, and separates the nasal fossae behind. It is thick and bifid above, thin 
below. 
Development.-The vomer at an early period consists of two laminae separated 
by a very considerable interval, and enclosing between them a plate of cartilage 
which is prolonged forward to form the remainder of the septum. Ossification com- 
mences in it by a single centre about the eighth week. From this nucleus the two 
laminae are formed. They begin to coalesce at the hinder part, but their union is 
not complete until after puberty. 
Articulations.-With six bones: two of the cranium, the sphenoid and eth- 
moid ; and four of the face, the two superior maxillary and the two palate bones; 
and with the cartilage of the septum. 
The vomer has no muscles attached to it. 
Fig. 169. 
Vomer. 
The Inferior Maxillary Bone, the largest and strongest bone of the face, serves 
for the reception of the lower teeth. It consists of a curved horizontal portion, the 
body, and two perpendicular portions, the rami, which join the back part of the 
body nearly at right angles. 
The Horizontal Portion, or body (Fig. 170), is convex in its general outline, 
and curved somewhat like a horseshoe. It presents for examination two surfaces 
and two borders. The external surface is convex from side to side, concave from 
above downward. In the median line is a vertical ridge, the symphysis, which 
The Inferior Maxillary Bone. 198 
THE SKELETON. 
extends from the upper to the lower border of the bone, and indicates the point of 
junction of the two pieces of which the bone is composed at an early period of life. 
The lower part of the ridge terminates in a prominent triangular eminence, the 
mental process [from mentum, the chin, not mens, the mind. The large develop- 
Fig. 170. 
Men tai 
firocess~ 
A/n if 1g 
Inferior Maxillary Bone, outer surface, side view. 
Groove tai* jaeutf* arty 
ment of the chin is very distinctive of man. The lower animals lack a chin, prop- 
erly so called]. On either side of the symphysis, just below the cavities for the 
incisor teeth, is a depression, the incisive fossa, for the attachment of the Levator 
Fig. 171. 
-GENIO-HYO-GLOSSUS 
GENIO-HYOIDEUS 
Mylo-hyoid Ridge 
B o dy 
Inferior Maxillary Bone, inner surface, side view. 
menti (or Levator labii inferioris); and, still more externally, a foramen, the mental 
tor amen, for the passage of the mental nerve and artery. This foramen is placed 
just below the root of the second bicuspid tooth. Running outward from the base THE INFERIOR MAXILLARY BONE. 
199 
of the mental process on each side is a well-marked ridge, the external oblique line. 
The ridge is at first nearly horizontal, but afterward inclines upward and backward, 
and is continuous with the anterior border of the ramus; it affords attachment to the 
Depressor labii inferioris and Depressor anguli oris; below it the Platysma myoides 
is attached. 
The internal surface (Fig. 171) is concave from side to side, convex from above 
downward. In the middle line is an indistinct linear depression corresponding to 
the symphysis externally; on either side of this depression, just below its centre, 
are four prominent tubercles, placed in pairs, two above and two below; they are 
called the genial tubercles \_ye\jziov, the chin] and afford attachment, the upper pair 
to the Genio-hyo-glossi muscles, the lower pair to the Genio-hyoidei muscles. Some- 
times the tubercles on each side are blended into one; at others they all unite into 
an irregular eminence; or, again, nothing but an irregularity may be seen on the 
surface of the bone at this part. On either side of the genial tubercles is an oval 
depression, the sublingual fossa, for lodging the sublingual gland; and beneath the 
fossa a rough depression on each side which gives attachment to the anterior belly 
of the Digastric muscle. At the back part of the sublingual fossa the internal 
oblique line (gnylo-hyoidean) commences; it is at first faintly marked, but becomes 
more distinct as it passes upward and outward, and is especially prominent opposite 
the last two molar teeth; it affords attachment throughout its whole extent to the 
Mylo-hyoid muscle, the Superior constrictor of the pharynx with the pterygo-max- 
illary ligament being attached above its posterior extremity, nearer the alveolai' 
margin. The portion of bone above this ridge is smooth, and covered by the mucous 
membrane of the mouth; the portion below presents an oblong depression, the 
submaxillary fossa, wider behind than in front, for the lodgment of the submax- 
illary gland. The external oblique line and the internal or mylo-hyoidean line 
divide the body of the bone into a superior or alveolar and an inferior or basilar 
portion. 
The superior or alveolar border is wider and its margins thicker behind than 
in front. It is hollowed into numerous cavities for the reception of the teeth: 
these cavities are sixteen in number, and vary in depth and size according to the 
teeth which they contain. To its outer side the Buccinator muscle is attached as 
far forward as the first molar tooth. The inferior border is rounded, longer than 
the superior, and thicker in front than behind; it presents a shallow groove just 
where the body joins the ramus, over which the facial artery turns. 
The Perpendicular Portions, or Rami, are of a quadrilateral form. Each 
presents for examination two surfaces, four borders, and two processes. The 
external surface is flat, marked with ridges, and gives attachment throughout 
nearly the whole of its extent to the Masseter muscle. The internal surface pre- 
sents about its centre the oblique aperture-of the inferior dental canal, for the 
passage of the inferior dental vessels and nerve. The margin of this opening is 
irregular; it presents in front a prominent ridge, surmounted by a sharp spine, 
which gives attachment to the internal lateral ligament of the lower jaw, and at 
its lower and back part a notch leading to a groove, the mylo-hyoidean, which runs 
obliquely downward to the back part , of the submaxillary fossa, and lodges the 
mylo-hyoid vessels and nerve: behind the groove is a rough surface, for the inser- 
tion of the Internal pterygoid muscle. The inferior dental canal runs obliquely 
downward and forward in the substance of the ramus, and then horizontally forward 
in the body; it is here placed under the alveoli, with which it communicates by small 
openings. On arriving at the incisor teeth it turns back to communicate with the 
mental foramen, giving off two small canals, which run forward, to be lost in the 
cancellous tissue of the bone beneath the incisor teeth. This canal, in the posterior 
two-thirds of the bone, is situated nearer the internal surface of the jaw, and in the 
anterior third nearer its external surface. Its walls are composed of compact tissue 
at either extremity and of cancellous in the centre. It contains the inferior dental 
vessels and nerve, from which branches are distributed to the teeth through small 
apertures at the bases of the alveoli. The upper border of the ramus is thin, and 200 
THE SKELETON. 
presents two processes separated by a deep concavity, the sigmoid notch. Of these 
processes, the anterior is the coronoid, the posterior the condyloid. 
The Coronoid Process is a thin, flattened, triangular eminence of bone which 
varies in shape and size in different subjects, and serves chiefly for the attachment 
of the Temporal muscle. Its external surface is smooth, and affords attachment to 
the Masseter and Temporal muscles. Its internal surface gives attachment to the 
Temporal muscle, and presents the commencement of a longitudinal ridge which is 
continued to the posterior part of the alveolar process. On the outer side of this 
ridge is a deep groove continued below on the outer side of the alveolar process; 
this ridge and part of the groove afford attachment, above, to the Temporal; below, 
to the Buccinator muscle. 
The Condyloid Process, shorter but thicker than the coronoid, consists of two 
portions-the condyle, and the constricted portion which supports the condyle, the 
neck. The condyle is of an oblong form, its long axis being transverse and set 
obliquely on the neck in such a manner that its outer end is a little more forward 
and a little higher than its inner. It is convex from before backward and from side 
to side, the articular surface extending farther on the posterior than on the anterior 
surface. The neck of the condyle is flattened from before backward, and strength- 
ened by ridges which descend from the fore part and sides of the condyle. Its lateral 
margins are narrow, and present externally a tubercle for the external lateral liga- 
ment. Its posterior surface is convex ; its anterior is hollowed out on its inner side 
by a depression (the pterygoid fossa) for the attachment of the External pterygoid. 
The lower border of the ramus is thick, straight, and continuous with the body 
of the bone. At its junction with the posterior border is the angle of the jaw, which 
is either inverted or everted, and marked by rough oblique ridges on each side, for 
the attachment of the Masseter externally and the Internal pterygoid internally; 
the stylo-maxillary ligament is attached to the bone between these muscles. The 
anterior border is thin above, thicker below, and continuous with the external 
oblique line. The posterior border is thick, smooth, rounded, and covered by the 
parotid gland. 
The Sigmoid Notch, separating the two processes, is a deep semilunar depres- 
sion crossed by the masseteric artery and nerve. 
Development.-The lower jaw is developed principally from membrane, but 
partly from cartilage. The bone is formed at such an early period of life-before, 
indeed, any other bone except the clavicle-that it has been found impossible at 
present to determine its earliest condition. It is generally believed, however, that 
each half is developed by several centres, which speedily unite. The greater part 
is formed from the fibrous tissue investing Meckel's cartilage (p. 118), but a small 
portion near the symphysis is developed from the anterior extremity of the cartilage 
itself; while the condyle and a part of the ramus are developed from another mass 
of cartilage. According to Callender, a separate ossific plate forms the floor of the 
dental groove. At birth the bone consists of two halves, united by a fibrous sym- 
physis in which ossification takes place during the first year. 
Changes produced in the Lower Jaw by Age. 
The changes which the lower jaw undergoes after birth relate-1, to the alterations effected 
in the body of the bone by the first and second dentitions, the loss of the teeth in the aged, and 
the subsequent absorption of the alveoli; 2, to the size and situation of the dental canal; and 3, 
to the angle at which the ramus joins with the body. 
At birth (Fig. 172) the bone consists of two lateral halves, united by fibro-cartilaginous tissue, 
in which one or two osseous nuclei are generally found. The body is a mere shell of bone, con- 
taining the sockets of the two incisor, the canine, and the two temporary molar teeth, imper- 
fectly partitioned from one another. The dental canal is of large size, and runs near the lower 
border of the bone, the mental foramen opening beneath the socket of the first molar. The angle 
is obtuse, and the condyloid portion nearly in the same horizontal line with the ramus; the neck 
of the condyle is short and bent backward. The coronoid process is of comparatively large size 
and situated at right angles with the rest of the bone. 
After birth (Fig. 173) the two segments of the bone become joined at the symphysis, from 
below upward, in the first year; but a trace of separation may be visible in the beginning of THE INFERIOR MAXILLARY BONE. 
201 
Side View of the Lower Jaw at Different Periods of Life. 
Fig. 172. At Birth. 
Fig. 173. At Puberty. 
Fig. 174. In the Adult. 
Fig. 175. In Old Age. 202 
THE SKELETON. 
the second year near the alveolar margin. The body becomes elongated in its whole length, but 
more especially behind the mental foramen, to provide space for the three additional teeth devel- 
oped in this part. The depth of the body becomes greater, owing to increased growth of the 
alveolar part, to afford room for the fangs of the teeth, and by thickening of the subdental por- 
tion, which enables the jaw to withstand the powerful action of the masticatory muscles ; but the 
alveolar portion is the deeper of the two, and, consequently, the chief part of the body lies above 
the oblique line. The dental canal, after the second dentition, is situated just above the level 
of the mylo-hyoid ridge, and the mental foramen occupies the position usual to it in the adult. 
The angle becomes less obtuse, owing to the separation of the jaws by the teeth. 
In the adult (Fig. 174) the alveolar and basilar portions of the body are usually of equal 
depth. The mental foramen opens midway between the upper and lower borders of the bone, 
and the dental canal runs nearly parallel with the mylo-hyoid line. The ramus is almost vertical 
in direction, and joins the body nearly at right angles. 
In old age (Figs. 175 and 176) the bone becomes greatly reduced in size; for with the loss of 
the teeth the alveolar process is absorbed, and the basilar part of the bone alone remains; con- 
[Fig. 176. 
Absorption of the Alveolar Processes of both Jaws, after loss of the teeth (Litch).] 
sequently, the chief part of the bone is below the oblique line. The dental canal, with the 
mental foramen opening from it, is close to the alveolar border. The rami are oblique in direc- 
tion, the angle obtuse, and the neck of the condyle more or less bent backward. 
Articulation.--With the glenoid fossae of the two temporal bones. 
Attachment of Muscles.-To fifteen pairs-to its external surface, commen- 
cing at the symphysis and proceeding backward: Levator menti, Depressor labii 
inferioris, Depressor anguli oris, Platysma myoides, Buccinator, Masseter; a portion 
of the Orbicularis oris (Accessorii orbicularis inferiores) is also attached to this sur- 
face. To its internal surface, commencing at the same point: Genio-hyo-glossus, 
Genio-hyoideus, Mylo-hyoideus, Digastric, Superior constrictor, Temporal, Internal 
pterygoid, External pterygoid. 
THE SUTURES. 
The bones of the cranium and face are connected to each other by means of Su- 
tures [Fig. 178, p. 209]. The sutures are rows of dentated processes of bone pro- 
jecting from the edge of either bone, and locking into one another; the dentations, THE SUTURES. 
203 
however, are confined to the external table, the edges of the internal table lying 
merely in apposition. The Cranial Sutures may be divided into three sets: 1, 
Those at the vertex of the skull; 2, those at the side of the skull; 3, those at 
the base. 
The sutures at the vertex of the skull are three: the sagittal, coronal, and 
lambdoid. 
The Sagittal Suture {interparietal} is formed by the junction of the two pari- 
etal bones, and extends from the middle of the frontal bone backward to the supe- 
rior angle of the occipital. In childhood, and occasionally in the adult when the 
two halves of the frontal bone are not united, it is continued forward to the root 
of the nose. This suture sometimes presents, near its posterior extremity, the 
parietal foramen on each side; and in front, where it joins the coronal suture, a 
space is occasionally left which encloses a large Wormian bone. 
The Coronal Suture {fronto-parietal} extends transversely across the vertex 
of the skull and connects the frontal with the parietal bones. It commences at the 
extremity of the greater wing of the sphenoid on one side, and terminates at the 
same point on the opposite side. The dentations of this suture are more marked 
at the sides than at the summit, and are so constructed that the frontal rests on the 
parietal above, whilst laterally the frontal supports the parietal. 
The Lambdoid Suture {occipito-parietal}, so called from its resemblance to the 
Greek letter A, connects the occipital with the parietal bones. It commences on 
each side at the mastoid portion of the temporal bone, and inclines upward to the 
end of the sagittal suture. The dentations of this suture are very deep and distinct, 
and are often interrupted by several small Wormian bones. 
The sutures at the side of the skull are also three in number: the spheno-pari- 
etal, squamo-parietal, and masto-parietal. They are subdivisions of a single suture 
formed between the lower border of the parietal and the sphenoid and temporal 
bones, and which extends from the lower end of the coronal suture in front to the 
lower end of the lambdoid suture behind. 
The Spheno-parietal is very short; it is formed by the tip of the great 
wing of the sphenoid, which overlaps the anterior inferior angle of the parietal 
bone. 
The Squamo-parietal or Squamous Suture is arched. It is formed by the 
squamous portion of the temporal bone overlapping the middle division of the lower 
border of the parietal. 
The Masto-parietal is a short suture, deeply dentated, formed by the posterior 
inferior angle of the parietal and the superior border of the mastoid portion of the 
temporal. 
The sutures at the base of the skull are-the basilar in the centre, and on each 
side the petro-occipital, the masto-occipital, the petrosphenoidal, and the squamo- 
sphenoidal. 
The Basilar Suture is formed by the junction of the basilar surface of the 
occipital bone with the posterior surface of the body of the sphenoid. At an early 
period of life a thin plate of cartilage exists between these bones, but in the adult 
they become fused into one. Between the outer extremity of the basilar suture 
and the termination of the lambdoid an irregular suture exists which is subdivided 
into two portions. The inner portion, formed by the union of the petrous part of 
the temporal with the occipital bone, is termed the petro-occipital. The outer 
portion, formed by the junction of the mastoid part of the temporal with the occip- 
ital, is called the masto-occipital. Between the bones forming the petro-occipital 
suture a thin plate of cartilage exists; in the masto-occipital is occasionally found 
the opening of the mastoid foramen. Between the outer extremity of the basi- 
lar suture and the spheno-parietal an irregular suture may be seen, formed by 
the union of the sphenoid with the temporal bone. The inner and smaller 
portion of this suture is termed the petrosphenoidal; it is formed between the 
petrous portion of the temporal and the great wing of the sphenoid; the outer 
portion, of greater length and arched, is formed between the squamous portion 204 
THE SKELETON. 
of the temporal and the great wing, of the sphenoid: it is called the squamo- 
sphenoidal. 
The cranial bones are connected with those of the face, and the facial bones with 
each other, by numerous sutures, which, though distinctly marked, have received no 
special names. The only remaining suture deserving especial consideration is the 
transverse. This extends across the upper part of the face, and is formed by the 
junction of the frontal with the facial bones: it extends from the external angular 
process of one side to the same point on the opposite side, and connects the frontal 
with the malar, the sphenoid, the ethmoid, tbe lachrymal, the superior maxillary, 
and the nasal bones on each side. 
The sutures remain separate for a considerable period after the complete forma- 
tion of the skull. It is probable that they serve the purpose of permitting the 
growth of the bones at their margins, while their peculiar formation, together with 
the interposition of the sutural ligament between the bones forming them, prevents 
the dispersion of blows or jars received upon the skull. Dr. Humphry remarks 
" that, as a general rule, the sutures are first obliterated at the parts in which the 
ossification of the skull was last completed-viz. in the neighborhood of the fon- 
tanelles ; and the cranial bones seem in this respect to observe a similar law to that 
which regulates the union of the epiphyses to the shafts of the long bones." The 
same author remarks that the time of their disappearance is extremely variable: 
they are sometimes found well marked in skulls edentulous with age, while in others 
which have only just reached maturity they can hardly be traced. 
THE SKULL. 
The Skull, formed by the union of the several cranial and facial bones already 
described, when considered as a whole, is divisible into five regions-a superior 
region or vertex, an inferior region or base, two lateral regions, and an anterior 
region, the face. 
Vertex of the Skull. 
The Superior Region, or Vertex, presents two surfaces, an external and an 
internal.1 
The external surface is bounded in front by the nasal eminence and supraorbital 
ridges ; behind, by the occipital protuberance and superior curved lines of the occip- 
ital bone; laterally, by an imaginary line extending from the outer end of the supe- 
rior curved line, along the temporal ridge, to the external angular process of the 
frontal. This surface includes the vertical portion of the frontal, the greater part 
of the parietal, and the superior third of the occipital bone; it is smooth, convex, 
of an elongated oval form, crossed transversely by the coronal suture, and from 
before backward by the sagittal, which terminates behind in the lambdoid. From 
before backward may be seen the frontal eminences and remains of the suture con- 
necting the two lateral halves of the frontal bone; on each side of the sagittal 
suture are the parietal foramen and parietal eminence, and still more posteriorly 
the convex surface of the occipital bone. 
The internal surface is concave, presents eminences and depressions for the 
convolutions of the cerebrum, and numerous furrows for the lodgment of branches 
of the meningeal arteries. Along the middle line of this surface is a longitudinal 
groove, narrow in front, where it terminates in the frontal crest, but broader behind, 
where it lodges the superior longitudinal sinus and by its margin affords attachment 
to the falx cerebri. On either side of it are several depressions for the Pacchjonian 
bodies, and at its back part the internal openings of the parietal foramina. This 
surface is crossed in front by the coronal suture; from before backward, by the 
sagittal; behind, by the lambdoid. 
The upper part of the skull above the level of the eyebrows is called the calvarium ; hence our 
word " calvary." ] BASE OF THE SKULL. 
205 
Base of the Skull. 
The Inferior Region, or Base of the Skull, presents two surfaces-an internal 
or cerebral, and an external or basilar. 
The internal or cerebral surface (Fig. 177) presents three fossae, called the 
anterior, middle, and posterior fossae of the cranium. 
Fig. 177. 
Groove for Stiver, longitud. Sinus ■ 
Grooves for Anter. Meningeal ASr 
Foramen Ca>ciin>- 
Cri'Sta, GaUi- 
Sltt for Ea.sal, 
Groove gnr INmeaiL 
Anterior Ethmoidal For... 
Orifices for Olfactory nerves- 
Posterior EHimoidid Fo/r- 
Ft/imoidal Spine - 
Olfaetory (Ztoovos 
Opt io forameit 
Optic Grooire- 
Olivary prorh 
Anterio r Clinoid' proc. 
Clinoid proc - 
fox teriov Clinoid, proc,. 
Groove for (ph nen'e 
For™ lac er am medium- 
Orifice vf Carotid Canal 
Depression for Gasserian Ganglion- 
Meat a s Auditor. ItVternus- 
Slit for Diura-Mdter - 
ffirp. Fetrosal groom - 
-For. lacerum poster ius - 
Anterior CondyloidFor.- 
Aqueduct. Veetibuli- 
Tostorior Condyloid For.- 
F o r a m e n 
M a<] nu m 
Mastoid Eon- 
-Past. AFeuinqcal Grooves- 
Base of the Skull, inner or cerebral surface. 206 
THE SKELETON. 
The Anterior Fossa is formed by the orbital plate of the frontal, the cribriform 
plate of the ethmoid, the ethmoidal spine, and the lesser wing of the sphenoid. It 
is the most elevated of the three fossae, convex externally where it corresponds to 
the roof of the orbit, concave in the median line in the situation of the cribriform 
plate of the ethmoid. It is traversed by three sutures-the ethmo-frontal, ethmo- 
sphenoidal, and frontosphenoidal-and lodges the anterior lobe of the cerebrum. 
It presents, in the median line, from before backward, the commencement of the 
groove for the superior longitudinal sinus and the crest for the attachment of the 
falx cerebri; the foramen caecum, an aperture formed by the frontal bone and the 
crista galli of the ethmoid, which, if pervious, transmits a small vein from the nose 
to the superior longitudinal sinus; behind the foramen caecum, the crista galli, the 
posterior margin of which affords attachment to the falx cerebri; on either side of 
the crista galli, the olfactory groove, which supports the bulb of the olfactory nerve, 
and presents three rows of foramina for its filaments, and in front a slit-like open- 
ing for the nasal branch of the ophthalmic [division of the fifth] nerve. On the 
outer side of each olfactory groove are the internal openings of the anterior and 
posterior ethmoidal foramina; the former, situated about the middle of the outer 
margin of the olfactory groove, transmits the anterior ethmoidal artery and the 
nasal nerve, which runs in a depression along the surface of the ethmoid to the 
slit-like opening above mentioned; whilst the posterior ethmoidal foramen opens 
at the back part of this margin under cover of the projecting lamina of the sphe- 
noid, and transmits the posterior ethmoidal artery and vein to the posterior eth- 
moidal cells. Farther back in the middle line is the ethmoidal spine, bounded 
behind by an elevated ridge separating two longitudinal grooves which support 
the olfactory nerves. The anterior fossa presents, laterally, eminences and depres- 
sions for the convolutions of the brain and grooves for the lodgment of the anterior 
meningeal arteries. 
The Middle Fossa, somewhat deeper than the preceding, is narrow in the middle 
line, but becomes wider at the side of the skull. It is bounded in front by the pos- 
terior margin of the lesser wing of the sphenoid, the anterior clinoid process, and 
the anterior margin of the optic groove; behind, by the superior border of the 
petrous portion of the temporal and the dorsum ephippii; externally, by the 
squamous portion of the temporal, anterior inferior angle of the parietal bone, 
and greater wing of the sphenoid. It is traversed by four sutures-the squamo- 
parietal, spheno-parietal, spheno-temporal, and petro-sphenoidal. 
In the middle line, from before backward, is the optic groove, which supports the 
optic commissure, and terminates on each side in the optic foramen, for the passage 
of the optic nerve and ophthalmic artery; behind the optic groove is the olivary 
process; and laterally, the anterior clinoid processes, to which are attached pro- 
cesses of the tentorium cerebelli. Farther back is the sella Turcica, a deep 
depression which lodges the pituitary gland, bounded in front by a small emi- 
nence on either side, the middle clinoid process, and behind by a broad square 
plate of bone, the dorsum ephippii, surmounted at each superior angle by a tuber- 
cle, the posterior clinoid process; beneath the latter process is a groove, for the 
sixth nerve. On each side of the sella Turcica is the cavernous groove; it is 
broad, shallow, and curved somewhat like the italic letter f; it commences behind 
the foramen lacerum medium, and terminates on the inner side of the anterior cli- 
noid process, and presents along its outer margin a ridge of bone, the lingula. This 
groove lodges the cavernous sinus, the internal carotid artery, and the nerves of the 
orbit. The sides of the middle fossa are of considerable depth ; they present emi- 
nences and depressions for the middle lobes of the brain, and grooves for the 
branches of the middle meningeal artery: the latter commence on the outer side 
of the foramen spinosum, and consist of two large branches, an anterior and a pos- 
terior, the former passing upward and forward to the anterior inferior angle of the 
parietal bone, the latter passing upward and backward. The following foramina 
may also be seen from before backward: Most anteriorly is the foramen lacerum 
anterius, or sphenoidal fissure, formed above by the lesser wing of the sphenoid; BASE OF THE SKULL. 
207 
below, by the greater wing; internally, by the body of the sphenoid; and com- 
pleted externally by the orbital plate of the frontal bone. It transmits the third, 
fourth, the three branches of the ophthalmic .division of the fifth, the sixth nerve, 
some filaments of the sympathetic, the orbital branch of the middle meningeal 
artery, a recurrent branch from the lachrymal artery, and the ophthalmic vein. 
Behind the inner extremity of the sphenoidal fissure is the foramen rotundum, for 
the passage of the second division of the fifth or superior maxillary nerve; still 
more posteriorly is seen a small orifice, the foramen Vesalii, an opening situated 
between the foramen rotundum and ovale, a little internal to both : it varies in size 
in different individuals, and is often absent; when present, it transmits a small vein. 
It opens below into the pterygoid fossa, just at the outer side of the scaphoid depres- 
sion. Behind and external to the latter opening is the foramen ovale, which trans- 
mits the third division of the fifth or inferior maxillary nerve, the small meningeal 
artery, and the small petrosal nerve.1 On the outer side of the foramen ovale is the 
foramen spinosum, for the passage of the middle meningeal artery ; and on the inner 
side of the foramen ovale, the foramen lacerum medium. The lower part of this aper- 
ture is filled up with cartilage in the recent state. The Vidian nerve pierces this 
cartilage. On the anterior surface of the petrous portion of the temporal bone is 
seen, from without inward, the eminence caused by the projection of the superior 
semicircular canal; outside this, a depression corresponding to the roof of the tym- 
panum, the groove leading to the hiatus Fallopii, for the transmission of the petrosal 
branch of the Vidian nerve and the petrosal branch of the middle meningeal artery ; 
beneath it, the smaller groove, for the passage of the lesser petrosal nerve; and near 
the apex of the bone, the depression for the Gasserian ganglion, and the orifice of 
the carotid canal, for the passage of the internal carotid artery and carotid plexus 
of nerves. 
The Posterior Fossa, deeply concave, is the largest of the three, and situated 
on a lower level than either of the preceding. It is formed by the occipital, the 
petrous and mastoid portions of the temporal, and the posterior inferior angle of 
the parietal bone; is crossed by three sutures, the petro-occipita], masto-occipital, 
the masto-parietal; and lodges the cerebellum, pons Varolii, and medulla oblongata. 
It is separated from the middle fossa in the median line by the dorsum ephippii, 
and on each side by the superior border of the petrous portion of the temporal 
bone. This border serves for the attachment of the tentorium cerebelli, is grooved 
externally for the superior petrosal sinus, and at its inner extremity presents a 
notch upon which rests the fifth nerve. The circumference of the fossa is bounded 
posteriorly by the grooves for the lateral sinuses. In the centre of this fossa is the 
foramen magnum, bounded on either side by a rough tubercle which gives attach- 
ment to the odontoid ligaments ; and a little above these are seen the internal open- 
ings of the anterior condyloid foramina. In front of the foramen magnum is the 
basilar process, grooved for the support of the medulla oblongata and pons Varolii, 
and articulating on each side with the petrous portion of the temporal bone, forming 
the petro-occipital suture, the anterior half of which is grooved for the inferior petro- 
sal sinus, the posterior half being encroached upon by the foramen lacerum posterius, 
or jugular foramen. This foramen presents three compartments: through the ante- 
rior the inferior petrosal sinus passes; through the posterior, the lateral sinus and 
some meningeal arteries; and through the middle, the ninth, tenth, and eleventh 
pairs of nerves.2 Above the jugular foramen is the internal auditory meatus, for 
the facial and auditory nerves and auditory artery; behind and external to this is 
the slit-like opening leading into the aqumductus vestibuli; whilst between the two 
latter, and near the superior border of the petrous portion, is a small triangular 
depression which lodges a process of the dura mater, and occasionally transmits a 
small vein into the substance of the bone. Behind the foramen magnum are the 
inferior occipital fossce, which lodge the hemispheres of the cerebellum, separated 
1 See foot-note, p. 178. 
2 [In Fig. 177, in the jugular foramen, the "8th pr" means the eighth pair of nerves in the enu- 
meration of Willis, and consists of the ninth, tenth, and eleventh of Sommerring.j 208 
THE SKELETON. 
from one another by the internal occipital crest, which serves for the attachment of 
the falx cerebelli and lodges the occipital sinus. The posterior fossae are surmounted 
above by the deep transverse the lodgment of the lateral sinuses. These 
channels, in their passage outward, groove the occipital bone, the posterior inferior 
angle of the parietal, the mastoid portion of the temporal, and the occipital just 
behind the jugular foramen, at the back part of which they terminate. Where this 
sinus grooves the mastoid part of the temporal bone the orifice of the mastoid fora- 
men may be seen, and just previous to its termination it has opening into it the 
posterior condyloid foramen. Neither foramen is constant. 
The external surface of the base of the skull (Fig. 178) is extremely irregular. 
It is bounded in front by the incisor teeth in the upper jaws; behind, by the supe- 
rior curved lines of the occipital bone; and laterally, by the alveolar arch, the 
lower border of the malar bone, the zygoma, and an imaginary line extending 
from the zygoma to the mastoid process and extremity of the superior curved line 
of the occiput. It is formed by the palate processes of the superior maxillary and 
palate bones, the vomer, the pterygoid processes, under surface of the great wing, 
spinous processes, and part of the body of the sphenoid, the under surface of the 
squamous, mastoid, and petrous portions of the temporal, and the under surface of 
the occipital bone. The anterior part of the base of the skull is raised above the 
level of the rest of this surface (when the skull is turned over for the purpose of 
examination), surrounded by the alveolar process, which is thicker behind than in 
front, and excavated by sixteen depressions for lodging the teeth of the upper jaw, 
die cavities varying in depth and size according to the teeth they contain. Imme- 
diately behind the incisor teeth is the anterior palatine fossa. At the bottom of 
this fossa may usually be seen four apertures: two placed laterally-the foramina 
of Stenson, 'which open above, one in the floor of each nostril, and transmit the 
anterior branch of the posterior palatine vessels; and two in the median line in 
the intermaxillary suture-the foramina, of Scarpa, one in front of the other, the 
anterior transmitting the left, and the posterior (the larger) the right, naso-palatine 
nerve. These two latter canals are sometimes wanting, or they may join to form a 
single one, or one of them may open into one of the lateral canals above referred to. 
The palatine vault is concave, uneven, perforated by numerous foramina, marked by 
depressions for the palatine glands, and crossed by a crucial suture formed by the 
junction of the,four bones of which it is composed. One or two small foramina in 
the alveolar margin behind the incisor teeth, occasionally seen in the adult, almost 
constant in young subjects, are called the incisive foramina; they transmit nerves 
and vessels to the incisor teeth. At each posterior angle of the hard palate is the 
posterior palatine foramen, for the transmission of the posterior palatine vessels 
and descending palatine nerves, and running forward and inward from it a groove 
for the posterior palatine vessels and anterior palatine nerve. Behind the posterior 
palatine foramen is the tuberosity of the palate bone, perforated by one or more acces- 
sory posterior palatine canals, and marked by the commencement of a ridge which 
runs transversely inward and serves for the attachment of the tendinous expansion 
of the Tensor palati muscle. Projecting backward from the centre of the posterior 
border of the hard palate is the posterior nasal spine, for the attachment of the 
Azygos uvulae. Behind and above the hard palate is the posterior aperture of the 
nares, divided into two parts by the vomer, bounded above by the body of the 
sphenoid, below by the horizontal plate of the palate bone, and laterally by the 
pterygoid processes of the sphenoid. Each aperture measures about an inch in the 
vertical and half an inch in the transverse direction. At the base of the vomer 
may be seen the expanded alm of this bone, receiving between them the rostrum 
of the sphenoid. Near the lateral margins of the vomer, at the root of the pterygoid 
processes, are the pterygo-palatine canals. The pterygoid process, which bounds 
the posterior nares on each side, presents near its base the pterygoid or Vidian 
canal, for the Vidian nerve and artery. Each process consists of two plates, which 
bifurcate at the extremity to receive the tuberosity of the palate bone, and are sep- 
arated behind by the pterygoid fossa, which lodges the Internal pterygoid muscle.. BASE OF THE SKULL. 
209 
Fig. 178. 
. Ant. palatinefossa 
Tra'ns-mits left Naso-palal. n. 
-Tranfantt'SAnt.palat i/ess. 
-Transmits right Nasopalai. 
_Aeees sory palatine 
Fora/mi/TLa. 
SjOLHE. 
UVUL/E 
- Ha mill atjjtoc 
SpJienoid.proc. of Pccla/te. 
"Tteryg o-poulatine C. 
-TENSOR TYMPANI. 
-PAa/rynycal Spina for sup. CONSTRICe 
if'Fustacluan tube Sc Co. milfo rile ns or 
-.LAXATOR TYMPANI. 
~Go,1ulL for Jacobso-ws n. 
~Aiiued<oct. Cochlea... 
~~Fot. lace rib mposterui s. 
- Gaiialfor Arnold's 
-Auricular fissure- 
Fora/men 
Ala.goiam. 
Ext. Occipital Crest. 
Base of the Skull, external surface. 210 
THE SKELETON. 
The internal plate is long and narrow, presenting on the outer side of its base the 
scaphoid fossa, for the origin of the Tensor palati muscle, and at its extremity the 
hamular process, around which the tendon of this muscle turns. The external 
pterygoid plate is broad, forms the inner boundary of the zygomatic fossa, and 
affords attachment by its outer surface to the External pterygoid muscle. 
Behind the nasal fossae in the middle line is the basilar surface of the occipital 
bone, presenting in its centre the pharyngeal spine, for the attachment of the Supe- 
rior constrictor muscle of the pharynx, with depressions on each side for the inser- 
tion of the Rectus capitis anticus, major and minor. At the base of the external 
pterygoid plate is the foramen ovale ; behind this, the foramen spinosum and the 
prominent spinous process of the sphenoid, which gives attachment to the internal 
lateral ligament of the lower jaw and the Laxator tympani and Tensor palati mus- 
cles. External to the spinous process is the glenoid fossa, divided into two parts 
by the Glaserian fissure (p. 171), the anterior portion concave, smooth, bounded in 
front by the eminentia articalaris, and serving for the articulation of the condyle of 
the lower jaw ; the posterior portion rough, bounded behind by the vaginal process, 
and serving for the reception of part of the parotid gland. Emerging from between 
the laminae of the vaginal process is the styloid process, and at the base of this pro- 
cess is the stylo-mastoid foramen, for the exit of the facial nerve and entrance of the 
stylo-mastoid artery. External to the stylo-mastoid foramen is the auricular fissure, 
for the auricular branch of the pneumogastric, bounded behind by the mastoid pro- 
cess. Upon the inner side of the mastoid process is a deep groove, the digastric 
fossa, and a little more internally the occipital groove, for the occipital artery. At 
the base of the internal pterygoid plate is a large and somewhat triangular aperture, 
the foramen lacerum medium, bounded in front by the great wing of the sphenoid, 
behind by the apex of the petrous portion of the temporal bone, and internally by 
the body of the sphenoid and basilar process of the occipital bone: it presents in 
front the posterior orifice of the Vidian canal; behind, the aperture of the carotid 
canal. The basilar surface of this opening is filled up in the recent state by a fibro- 
cartilaginous substance; across its upper or cerebral aspect pass the internal carotid 
artery and Vidian nerve. External to this aperture the petrosphenoidal suture is 
observed, at the outer termination of which are seen the orifice of the canal for the 
Eustachian tube and that for the Tensor tympani muscle Behind this suture is 
seen the under surface of the petrous portion of the temporal bone, presenting, from 
within outward, the quadrilateral rough surface, part of which affords attachment to 
the Levator palati and Tensor tympani muscles; external to this surface the orifices 
of the carotid canal and the aquaeductus cochleae, the former transmitting the inter- 
nal carotid artery and the ascending branches of the superior cervical ganglion of 
the sympathetic, the latter serving for the passage of a small artery and vein to the 
cochlea. Behind the carotid canal is a large aperture, the jugular fossa, formed in 
front by the petrous portion of the temporal, and behind by the occipital; it is gen- 
erally larger on the right than on the left side, and is divided into three compart- 
ments by processes of dura mater. The anterior is for the passage of the inferior 
petrosal sinus ; the posterior for the lateral sinus and some meningeal branches from 
the occipital and ascending pharyngeal arteries; the central one for the ninth, tenth, 
and eleventh cranial nerves. On the ridge of bone dividing the carotid canal from 
the jugular fossa is the small foramen for the transmission of Jacobson's nerve ; and 
on the outer wall of the jugular foramen, near the root of the styloid process, is the 
small aperture for the transmission of Arnold's nerve. Behind the basilar surface 
of the occipital bone is tde foramen magnum, bounded on each side by the condyles, 
rough internally for the attachment of the check ligaments, and presenting exter- 
nally a rough surface, the jugular process, which serves for the attachment of the 
Rectus lateralis. On either side of each condyle anteriorly is the anterior condyloid 
fossa, perforated by the anterior condyloid foramen, for the passage of the hypo- 
glossal nerve and a meningeal artery. Behind each condyle are the posterior con- 
dyloid fossae, perforated on one or both sides by the posterior condyloid foramina, 
for the transmission of a vein to the lateral sinus. Behind the foramen magnum is LATERAL REGION OF THE SKULL. 
211 
the external occipital crest, terminating above at the external occipital protuberance, 
whilst on each side are seen the superior and inferior curved lines: these, as well as 
the surfaces of bone between them, are rough, for the attachment of the muscles, 
which are enumerated on p. 164. 
Lateral Region of the Skull. 
The Lateral Region of the skull is of a somewhat triangular form, the base of 
the triangle being formed by a line extending from the external angular process of 
the frontal bone, along the temporal ridge, backward to the outer extremity of the 
superior curved line of the occiput; and the sides by two lines, the one drawn 
Fig. 179. 
Ft onia I 
Side View of the Skull. 
downward and backward from the external angular process of the frontal bone to 
the angle of the lower jaw, the other from the angle of the jaw upward and back- 
ward to the extremity of the superior curved line. This region is divisible into 
three portions-temporal, mastoid, and .zygomatic. 
The Temporal Fossa. 
The Temporal fossa is bounded above and behind by the temporal ridge, which 
extends from the external angular process of the frontal upward and backward 
across the frontal and parietal bones, curving downward behind to terminate in the 
posterior root of the zygomatic process. In front it is bounded by the frontal, malar, 212 
THE SKELETON. 
and great wing of the sphenoid; externally, by the zygomatic arch, formed con- 
jointly by the malar and temporal bones; below, it is separated from the zygomatic 
fossa by the pterygoid ridge, seen on the outer surface of the great wing of the 
sphenoid. This fossa is formed by five bones-part of the frontal, great wing of 
the sphenoid, parietal, squamous portion of the temporal, and malar bones; and is 
traversed by six sutures-the transverse facial, spheno-malar, coronal, spheno-pari- 
etal, squamo-parietal, and squamo-sphenoidal. It is deeply concave in front, con- 
vex behind, traversed by grooves which lodge branches of the deep temporal 
arteries, and filled by the Temporal muscles. 
The Mastoid Portion of the side of the skull is bounded in front by the anterior 
root of the zygoma; above, by a line which runs from the posterior root of the 
zygoma to the end of the masto-parietal suture; behind and below, by the masto- 
occipital suture. It is formed by the mastoid and part of the squamous and petrous 
portions of the temporal bone; its surface is convex and rough for the attachment 
of muscles, and presents, from behind forward, the mastoid foramen, the mastoid 
process, the external auditory meatus, surrounded by the auditory process; and, 
most anteriorly, the glenoid fossa, bounded in front by the eminentia articularis, 
behind by the vaginal process. 
The Zygomatic Fossa. 
The Zygomatic fossa is an irregularly-shaped cavity situated below and on the 
inner side of the zygoma, bounded in front by the tuberosity of the superior maxil- 
lary bone and the ridge which descends from its malar process; behind, by the 
posterior border of the pterygoid process and the eminentia articularis; above, by 
the pterygoid ridge on the outer surface of the great wing of the sphenoid and 
squamous portion of the temporal; below, by the alveolar border of the superior 
maxilla; internally, by the external pterygoid plate; and externally, by the zygo- 
matic arch and ramus of the lower jaw. It contains the lower part of the Tem- 
poral, the External, and Internal pterygoid muscles, the internal maxillary artery 
and inferior maxillary nerve, and their branches. At its upper and inner part may 
be observed two fissures, the spheno-maxillary and pterygo-maxillary. 
The Spheno-maxillary fissure, horizontal in direction, opens into the outer and 
back part of the orbit. It is formed above by the lower border of the orbital sur- 
face of the great wing of the sphenoid ; below, by the external border of the orbital 
surface of the superior maxilla and a small part of the palate bone; externally, by 
a small part of the malar bone ;l internally it joins at right angles with the pterygo- 
maxillary fissure. This fissure opens a communication from the orbit into three 
fossae-the temporal, zygomatic, and spheno-maxillary; it transmits the superior 
maxillary nerve and its orbital branch, the infraorbital artery, and ascending 
branches from Meckel's ganglion. 
The Pterygo-maxillary fissure is vertical, and descends at right angles from 
the inner extremity of the preceding; it is an elongated interval formed by the 
divergence of the superior maxillary bone from the pterygoid process of the sphe- 
noid. It serves to connect the spheno-maxillary fossa with the zygomatic, and 
transmits branches of the internal maxillary artery. It forms the entrance from 
the zygomatic fossa to 
The Spheno-maxillary Fossa. 
The Spheno-maxillary fossa is a small triangular space situated at the angle 
of junction of the spheno-maxillary and ptery go-maxillary fissures, and placed 
beneath the apex of the orbit. It is formed above by the under surface of the 
body of the sphenoid and by the orbital plate of the palate bone; in front by the 
superior maxillary bone; behind, by the anterior surface of the base of the ptery- 
1 Occasionally the superior maxillary bone and the sphenoid articulate with each other at the 
anterior extremity of this fissure; the malar is then excluded from entering into its formation. ANTERIOR REGION 01 THE SKULL. 
213 
goid process of the sphenoid; internally, by the vertical plate of the palate. This 
fossa has three fissures terminating in it-the sphenoidal, spheno-maxillary, and 
pterygo-maxillary; it communicates with three fossse-the orbital, nasal, and zygo- 
matic-and with the cavity of the cranium, and has opening into it five foramina. 
Of these there are three on the posterior wall: the foramen rotundum above; 
below, and internal to this, the Vidian; and, still more inferior and internal, the 
pterygo-palatine. On the inner wall is the spheno-palatine foramen, by which the 
spheno-maxillary communicates with the nasal fossa, and below is the superior 
orifice of the posterior palatine canal, besides occasionally the orifices of two or 
three accessory posterior palatine canals. The fossa contains the superior maxillary 
nerve and Meckel's ganglion and the termination of the internal maxillary artery. 
Anterior Region of the Skull. 
The Anterior Region of the skull, which forms the face, is of an oval form, 
presents an irregular surface, and is excavated for the reception of the two principal 
organs of sense, the eye and the nose. It is bounded above by the nasal eminence 
and margins of the orbit; below, by the prominence of the chin; on each side, by 
the malar bone and anterior margin of the ramus of the jaw. In the median line 
is seen, from above downward, the nasal eminence, which indicates the situation of 
the frontal sinuses, and diverging from which are the superciliary ridges, which 
support the eyebrows. Beneath the nasal eminence is the arch of the nose, formed 
by the nasal bones and the nasal processes of the superior maxillary. The nasal 
arch is convex from side to side, concave from above downward, presenting in the 
median line the internasal suture formed between the nasal bones; laterally the 
naso-maxillary suture formed between the nasal bone and the nasal process of the 
superior maxillary bone, both these sutures terminating above in that part of the 
transverse suture which connects the nasal bones and nasal processes of the superior 
maxillary with the frontal. Below the nose is seen the opening of the anterior 
nares, which is heart-shaped, with the narrow end upward, and presents laterally 
the thin sharp margins serving for the attachment of the lateral cartilages of the 
nose; and in the middle line, below a prominent process, the anterior nasal spine, 
bounded by two deep notches. Below this is the intermaxillary suture, and on 
each side of it the incisive fossa. Beneath this fossa is the alveolar process of the 
upper and lower jaw, containing the incisor teeth, and at the lower part of the 
median line the symphysis of the chin, the mental eminence, and the incisive fossa 
of the lower jaw. 
On each side, proceeding from above downward, is the supraorbital ridge, ter- 
minating externally in the external angular process at its junction with the malar, 
and internally in the internal angulai' process; toward the inner third of this ridge 
is the supraorbital notch or foramen, for the passage of the supraorbital vessels and 
nerve, and at its inner side a slight depression, for the attachment of the pulley of 
the Superior oblique muscle. Beneath the supraorbital ridge is the opening of the 
orbit, bounded externally by the orbital ridge of the malar bone; below, by the 
orbital ridge formed by the malar, superior maxillary, and lachrymal bones; inter- 
nally, by the nasal process of the superior maxillary and the internal angular pro- 
cess of the frontal bone. On the outer side of the orbit is the quadrilateral anterior 
surface of the malar bone, perforated by one or two small malar foramina. Below 
the inferior margin of the orbit is the infraorbital foramen, the termination of the 
infraorbital canal; and beneath this the canine fossa, which gives attachment to the 
Levator anguli oris, bounded below by the alveolar processes, containing the teeth 
of the upper and lower jaw. Beneath the alveolar arch of the lower jaw is the 
mental foramen for the passage of the mental nerve and artery, the external oblique 
line; and at the lower border of the bone, at the point of junction of the body 
with the ramus, a shallow groove for the passage of the facial artery. 214 
THE SKELETON. 
The Orbits. 
The Orbits (Fig. 180) are two quadrilateral pyramidal cavities situated at the 
upper and anterior part of the face, their bases being directed forward and outward, 
and their apices backward and inward, so that the axes of the two, if continued 
backward, would meet over the body of the sphenoid bone. Each orbit is formed 
Fig. 180. 
TENBO OCULI 
interior 
Nares 
Ant. Nasal Spine ' 
Incisive Jos see 
(ftcofefor Fa-ccal a¥ 
Anterior Region of the Skull. 
of seven bones-the frontal, sphenoid, ethmoid, superior maxillary, malar, lachrymal, 
and palate; but three of these, the frontal, ethmoid, and sphenoid, enter into the 
formation of both orbits, so that the two cavities are formed of eleven bones only. 
Each cavity presents for examination a roof, a floor, an inner and an outer wall, 
four angles, a circumference or base, and an apex. The roof is concave, directed 
downward and forward, and formed in front by the orbital plate of the frontal, 
behind by the lesser wing of the sphenoid. This surface presents internally the 
depression for the fibro-cartilaginous pulley of the Superior oblique muscle; exter- 
nally, the depression for the lachrymal gland; and posteriorly, the suture connect- 
ing the frontal and lesser wing of the sphenoid. 
The floor is nearly flat, and of less extent than the roof; it is formed chiefly by 
the orbital process of the superior maxillary; in front, to a small extent, by the 
orbital process of the malar, and behind by the orbital surface of the palate. This 
surface presents at its anterior and internal part, just external to the lachrymal THE NASAL FOSSAE. 
215 
canal, a depression for the attachment of the Inferior oblique muscle; externally, 
the suture between the malar and superior maxillary bones; near its middle, the 
infraorbital groove; and posteriorly, the suture between the maxillary and palate 
bones. 
The inner wall is flattened, and formed from before backward by the nasal pro- 
cess of the superior maxillary, the lachrymal, os planum of the ethmoid, and a small 
part of the body of the sphenoid. This surface presents the lachrymal groove and 
crest of the lachrymal bone, and the sutures connecting the ethmoid with the lach- 
rymal bone in front and the sphenoid behind. 
The outer wall is formed in front by the orbital process of the malar bone; 
behind, by the orbital plate of the sphenoid. On it are seen the orifices of one or 
two malar canals and the suture connecting the sphenoid and malar bones. 
Angles.-The superior external angle is formed by the junction of the upper 
and outer walls; it presents, from before backward, the suture connecting the fron- 
tal with the malar in front, and with the orbital plate of the greater wing of the 
sphenoid behind; quite posteriorly is the foramen lacerum anterius, or sphenoidal 
fissure, which transmits the third, fourth, the ophthalmic division of the fifth, and 
the sixth nerves, some filaments from the cavernous plexus of the sympathetic, the 
orbital branch of the middle meningeal artery, a recurrent branch from the lach- 
rymal artery, and the ophthalmic vein. The superior internal angle is formed by 
the junction of the upper and inner wall, and presents the suture connecting the 
frontal bone with the lachrymal in front and with the ethmoid behind. This suture 
is perforated by two foramina, the anterior and posterior ethmoidal, the former trans- 
mitting the anterior ethmoidal vessels and nasal nerve, the latter the posterior eth- 
moidal artery and vein. The inferior external angle, formed by the junction of the 
outer wall and floor, presents the spheno-maxillary fissure, which transmits the infra- 
orbital vessels and superior maxillary nerve, the ascending branches from the spheno- 
palatine ganglion, and the orbital branch of the superior maxillary nerve. The 
inferior internal angle is formed by the union of the lachrymal and os planum of 
the ethmoid with the superior maxillary and palate bones. The circumference or 
base of the orbit, quadrilateral in form, is bounded above by the supraorbital arch; 
below, by the anterior border of the orbital plate of the malar, superior maxillary, 
and lachrymal bones; externally, by the external angular process of the frontal 
and the malar bones; internally, by the internal angular process of the frontal and 
the nasal process of the superior maxillary. The circumference is marked by three 
sutures-the fronto-maxillary internally, the fronto-malar externally, and the malo- 
maxillary below; it contributes to the formation of the lachrymal groove, and pre- 
sents, above, the supraorbital notch (or foramen), for the passage of the supraorbital 
artery, veins, and nerve. The apex, situated at the back of the orbit, corresponds 
to the optic foramen, a short circular canal which transmits the optic nerve and 
ophthalmic artery. It will thus be seen that there are nine openings communicating 
with each orbit-viz. the optic foramen, foramen lacerum anterius, spheno-maxillary 
fissure, supraorbital foramen, infraorbital canal, anterior and posterior ethmoidal 
foramina, malar foramina, and lachrymal canal. 
The Nasal Fossje. 
The Nasal Fossae are two large irregular cavities situated on either side of the 
middle line of the face, extending from the base of the cranium to the roof of the 
mouth, and separated from each other by a thin vertical septum. They communi- 
cate by two large apertures, the anterior nares, with the front of the face, and 
with the pharynx behind by the two posterior nares. These fossae are much nar- 
rower above than below, and in the middle than at the anterior or posterior open- 
ings : their depth, which is considerable, is much greater in the middle than at 
either extremity. Each nasal fossa communicates with four sinuses-the frontal 
above, the sphenoidal behind, and the maxillary and ethmoidal on either side. 
Each fossa also communicates with four cavities: with the orbit by the lachrymal 216 
THE SKELETON. 
canal, with the mouth by the anterior palatine canal, with the cranium by the olfac- 
tory foramina, and with the spheno-maxillary fossa by the spheno-palatine foramen; 
and they occasionally communicate with each other by an aperture in the septum. 
The bones entering into their formation are fourteen in number: three of the cra- 
nium, the frontal, sphenoid, and ethmoid, and all the bones of the face, excepting 
the malar and lower jaw. Each cavity is bounded by a roof, a floor, an inner and 
an outer wall. 
The upper wall, or roof (Fig. 181), is long, narrow, and concave from before 
backward; it is formed in front by the nasal bones and nasal spine of the frontal, 
which are directed downward and forward; in the middle, by the cribriform lamella 
Fig. 181. 
tiooj 
Prole passed through 
Naso-lachrpmal Canal 
Nasal Spine of Frontal Bone 
Natal foils 
Horizontal Flats of Ethmoid 
Bristle passed through 
[nJundid* U'lwn1 ■ 
Brae. rfSujMu. 
Ou,ter Wall 
].a.ch.rifmalr 
-UncPfmmltroc of ditto 
■Inftrior Tu rbt natcii 
PaLate, 
SupCTLOT Meatus 
-Middle Meafu* 
Meatus 
Floor 
Ant. Nasal Spvne 
Palate Proc. of 8 up Max. 
['alate. Proc, of Palate- 
Post. Nasal 8pine 
Ant. Palatine Canal 
Roof, Floor, and Outer Wall of Left Nasal Fossa. 
of the ethmoid, which is horizontal; and behind, by the under surface of the body 
of the sphenoid and sphenoidal turbinated bones, which are directed downward and 
backward. This surface presents, from before backward, the internal aspect of the 
nasal bones; on their outer side, the suture formed between the nasal bone and the 
nasal process of the superior maxillary; on their inner side, the elevated crest which 
receives the nasal spine of the frontal and the perpendicular plate of the ethmoid, 
and articulates with its fellow of the opposite side; whilst the surface of the bones 
is perforated by a few small vascular apertures and presents the longitudinal groove 
for the nasal nerve: farther back is the transverse suture, connecting the frontal 
with the nasal in front and the ethmoid behind, the olfactory foramina and nasal 
slit on the under surface of the cribriform plate, and the suture between it and the 
sphenoid behind: quite posteriorly are seen the sphenoidal turbinated bones, the 
orifices of the sphenoidal sinuses, and the articulation of the alm of the vomer with 
the under surface of the body of the sphenoid. 
The floor is flattened from before backward, concave from side to side, and wider 
in the middle than at either extremity. It is formed in front by the palate process 
of the superior maxillary; behind, by the palate process of the palate bone. The THE NASAL FOSSAE. 
217 
surface presents, from before backward, the anterior nasal spine; behind this, the 
upper orifices of the anterior palatine canal; internally, the elevated crest which 
articulates with the vomer; and behind, the suture between the palate and superior 
maxillary bones and the posterior nasal spine. 
The inner wall, or septum (Fig. 182), is a thin vertical partition which sepa- 
rates the nasal fossae from one another; it is occasionally perforated, so that the 
fossae communicate, and it is frequently deflected considerably to one side.1 It is 
formed in front by the crest of the nasal bones and nasal spine of the frontal; in 
Fig. 182. 
Unstrv'tn- of Splv/nm.d. 
Crext; of Nasal 
husciL Spine, ojFrontal IF 
Penrjienclicala,r Plate 
of Ethmoid. 
Space for Triangular 
Cartilage of Septum 
_ Crest of Palate Bane 
Crest of Bup.MaxiU.Bone 
Inner Wall of Nasal Fossse, or Septum of Nose. 
the middle, by the perpendicular lamella of the ethmoid; behind, by the vomer and 
rostrum of the sphenoid; below, by the crest of the superior maxillary and palate 
bones. It presents in front a large triangular notch which receives the triangular 
cartilage of the nose; above, the lower orifices of the olfactory canals; and behind, 
the guttural edge of the vomer. Its surface is marked by numerous vascular and 
nervous canals and the groove for the naso-palatine nerve, and is traversed by 
sutures connecting the bones of which it is formed. 
The outer wall (Fig. 181) is formed in front by the nasal process of the supe- 
rior maxillary and lachrymal bones; in the middle, by the ethmoid and inner sur- 
face of the superior maxillary and inferior turbinated bones; behind, by the vertical 
plate of the palate bone and the internal pterygoid plate of the sphenoid. This 
surface presents three irregular longitudinal passages, or meatuses [Figs. 181 and 
183], formed between three horizontal plates of bone that spring from it; they are 
termed the superior, middle, and inferior meatuses of the nose. The superior mea- 
tus, the smallest of the three, is situated at the upper and back part of each nasal 
fossa, occupying the posterior third of the outer wall. It is situated between the 
superior and middle turbinated bones, and has opening into it two foramina-the 
spheno-palatine at the back of its outer wall, and the posterior ethmoidal cells at 
1 See foot-note, p. 181. 218 
THE SKELETON. 
the front part of the upper wall. The opening of the sphenoidal sinuses is usually 
at the upper and back part of the nasal fossae immediately behind the superior tur- 
binated bone. The middle meatus is situated between the middle and inferior tur- 
binated bones, and occupies the posterior two-thirds of the outer wall of the nasal 
[Fig. 183. 
CTH.CELLsi 
-ORBIT 
SUPR. 
MEATUS 
L-MID. 
SUPER. 
TURB. 
MID. 
TURB, 
INFER- 
VTURB. 
Ng MEATUS 
Transverse Vertical (z. e. coronal) Section of the Nasal Fossae at the plane of the second molar teeth, 
seen from behind (Hirschfeldt).] 
fossa. It presents two apertures. In front is the orifice of the infundibulum, 
by which the middle meatus communicates with the anterior ethmoidal cells, and 
through these with the frontal sinuses. At the centre of the outer wall is the ori- 
fice of the antrum, which varies somewhat as to its exact position in different skulls. 
The inferior meatus, the largest of the three, is the space between the inferior turbi- 
nated bone and the floor of the nasal fossa. It extends along the entire length of 
the outer wall of the nose, is broader in front than behind, and presents anteriorly 
the lower orifice of the lachrymal canal. 
[Fig. 184. 
Rhinoscopic Image: 1, Vomer, or nasal septum ; 2, floor of nose; 3, superior meatus; 4, middle meatus; 5, supe- 
rior turbinated bone; 6, middle turbinated bone; 7, inferior turbinated bone; 8, pharyngeal orifice of Eus- 
tachian tube; 9, upper portion of Rosenmuller's groove; 11, Glandular tissue at the anterior portion of 
vault of pharynx; 12, uvula and posterior surface of velum (Seiler).] 
[The anterior nares are the two pear-shaped openings of the nose on the face. 
By lifting the tip of the nose and dilating the opening, we can get a good view of 
the septum and the inferior turbinated bone. The anterior extremity of the middle 
turbinated can also be seen. Both of these are covered by the mucous membrane, 
which often becomes hypertrophied in nasal catarrh. THE NASAL FOSSAE. 
219 
The posterior nares are the two oval openings of the nose posteriorly into the 
naso-pharynx. They are much smaller in the body than in the skull, since the 
mucous membrane narrows them. Fig. 184 shows them, together with the adja- 
cent parts, as they are best examined in the living by the rhinoscopic mirror. 
Notice in this view of the posterior nares the opening of the Eustachian tube (8) 
and the parts about it. The picture is somewhat more distinct and extensive than 
we usually see it. 
The posterior nares sometimes require to be plugged in hemorrhage from the nose 
by passing a string by means of a curved instrument, such as Bellocq's canula or a 
male catheter, through the inferior meatus, behind the soft palate and out through the 
mouth. A pledget of cotton is then attached to the end of the string passing through 
the mouth, and can be drawn into the posterior nares by the end through the nose.] 
The Hyoid bone is named from its resemblance to the Greek upsilon ; it is also 
called the lingual bone, because it supports the tongue and gives attachment to its 
numerous muscles. It is a bony arch shaped like a horseshoe, and consisting of 
five segments-a body, two greater cornua, and two lesser cornua. It is suspended 
from the tip of the styloid processes of the temporal bones by ligamentous bands, 
the stylo-hyoid ligaments. 
The body (basihyal') forms the central part of the bone, and is of a quadrilat- 
eral form: its anterior surface (Fig. 185), convex, directed forward and upward, is 
divided into two parts by a ver- 
tical ridge which descends along 
the median line and is crossed 
at right angles by a horizontal 
ridge, so that this surface is 
divided into four muscular de- 
pressions. At the point of meet- 
ing of these two lines is a prom- 
inent elevation, the tubercle. 
The portion above the horizon- 
tal ridge is directed upward, and 
is sometimes described as the 
superior border. The anterior 
surface gives attachment to the 
Genio-hyoid in the greater part 
of its extent; above, to the Ge- 
nio-hyo-glossus; below, to the 
Mylo-hyoid, Stylo-hyoid, and 
aponeurosis of the Digastric (suprahyoid aponeurosis); and between these to part 
of the Hyo-glossus. The posterior surface is smooth, concave, directed backward 
and downward, and separated from the epiglottis by the thyro-hyoid membrane and 
by a quantity of loose areolar tissue. The superior border is rounded, and gives 
attachment to the thyro-hyoid membrane and part of the Genio-hyo-glossi muscles. 
The inferior border gives attachment, in front, to the Sterno-hyoid; behind, to part 
of the Thyro-hyoid; and to the Omo-hyoid at its junction with the great cornu. The 
lateral surfaces are small, oval, convex facets, covered with cartilage for articulation 
with the greater cornua. 
The Greater Cornua (thyro-liyals) project backward from the lateral surfaces of 
the body; they are flattened from above downward, diminish in size from before 
backward, and terminate posteriorly in a tubercle for the attachment of the thyro- 
hyoid ligament. Their outer surface gives attachment to the Hyo-glossus; their 
upper border, to the Middle constrictor of the pharynx ; their lower border, to part 
of the Thyro-hyoid muscle. 
The Lesser Cornua (cerato-hyals) are two small conical-shaped eminences 
Hyoid Bone. 
Fig. 185. 
Greater Cornu. 
Middle Constrictor of Pharynx. 
Hyo-glossus., 
Lesser Cornu. 
Genio-hyo-glossus. 
Body.. 
Thyro-hyoid. 
Stylo-hyoid. 
Omo-hyoid. 
Mylo-hyoid. 
Genio-hyoid. Sterno-hyoid. 
Hyoid Bone, anterior surface (enlarged). 220 
THE SKELETON. 
attached by their bases to the angles of junction between the body and greater 
cornua, and giving attachment by their apices to the stylo-hyoid ligaments.1 In 
youth the great cornua are connected to the body by cartilaginous surfaces and held 
together by ligaments; in middle life they usually become joined. The smaller 
cornua are connected to the body of the bone by a distinct diarthrodial joint, which 
usually persists throughout life, but occasionally becomes ankylosed. 
Development.-By five centres: one for the body and one for each cornu. Ossi- 
fication commences in the body and greater cornua toward the end of foetal life, those 
of the cornua first appearing. Ossification at the lesser cornua commences some 
months after birth. 
Attachment of Muscles.-Sterno-hyoid, Thyro-hyoid, Omo-hyoid, aponeurosis 
of the Digastricus, Stylo-hyoid, Mylo-hyoid, Genio-hyoid, Genio-hyo-glossus, Hyo- 
glossus, Middle constrictor of the pharynx, and occasionally a few fibres of the Lin- 
gualis. It also gives attachment to the thyro-hyoidean membrane and the stylo- 
hyoid, thyro-hyoid, and hyo-epiglottic ligaments. 
THE THORAX. 
The Thorax, or Chest, is an osseo-cartilaginous cage intended to contain and 
protect the principal organs of respiration and circulation. It is conical in shape, 
flattened from before backward, and longer behind than in front. It is constructed 
in all vertebrate animals on the same type, consisting of a sternum in front, a part 
of the vertebral column behind, and the ribs on either side. All these parts are 
not, however, invariably present, and in man the anterior parts of the ribs are 
replaced by the costal cartilages. In the human thorax the transverse diameter 
exceeds the antero-posterior one, the cavity being spread out laterally, but in the 
lower orders of mammals the converse is the case, the antero-posterior exceeding the 
lateral diameter. The posterior surface of the thorax is formed by the twelve dorsal 
vertebrae and the posterior part of the ribs. It is convex from above downward, 
and presents on either side of the middle line a deep groove in consequence of the 
direction forward and inward which the ribs take from their angles to their verte- 
bral extremities. The anterior surface is flattened, slightly convex, and inclined 
forward from above downward. It is formed by the sternum and costal cartilages. 
The lateral surfaces are convex ; they are formed by the ribs, separated from one 
another by spaces, the intercostal spaces. These are eleven in number, and are 
occupied by the intercostal muscles. The upper opening of the thorax is reniform 
in shape, formed by the first dorsal vertebra behind, the upper margin of the ster- 
num in front, and the first rib on either side. It slopes downward and forward, so 
that the anterior part of the ring is on a lower level than the posterior. It also 
differs in the two sexes: the upper margin of the sternum in the male is on a level 
with the lower part of the body of the second dorsal vertebra, whereas in the female 
it is on a level with the lower part of the body of the third. The lower opening is 
formed by the twelfth dorsal vertebra behind, by the twelfth rib at the sides, and in 
front by the cartilages of the tenth, ninth, eighth, and seventh ribs, which ascend 
on either side and form an angle, the subcostal angle, from the centre of which the 
ensiform cartilage projects. 
The Sternum. 
The Sternum the chest) (Figs. 186, 187) is a flat, narrow bone situ- 
ated in the median line of the front of the chest, and consisting, in the adult, of 
three portions. It has been likened to an ancient sword: the upper piece, repre- 
senting the handle, is termed the manubrium ; the middle and largest piece, which 
represents the chief part of the blade, is termed the gladiolus; and the inferior 
1 These ligaments in many animals are distinct bones, and in man are occasionally ossified to a 
certain extent. THE THORAX. 
221 
Fig. 186. Sternum and Costal Cartilages. 
SIERNO-CLEFDO. MASTOID 
SUBCLAVIUS \ 
STERND- 
< HYOID 
[for I ? 
Costal 
Fig. 187. Posterior Surface of Sternum. 222 
THE SKELETON. 
piece, which is likened to the point of the sword, is termed the ensiform or xiphoid, 
appendix. In its natural position its inclination is oblique from above downward 
and forward. It is flattened in front, concave behind, broad above, becoming nar- 
rowed at the point where the first and second pieces are connected; after which it 
again widens a little, and is pointed at its extremity. Its average length in the 
adult is six inches, being rather longer in the male than in the female. [Its three 
pieces form three planes, forming obtuse angles at their junctions. The line of 
junction of the first and second portions is always readily seen and felt, and is a 
guide to the cartilages of the second ribs.] 
The First Piece of the sternum, or Manubrium (presternum), is of a some- 
what triangular form, broad and thick above, narrow below at its junction with the 
middle piece. Its anterior surface, convex from side to side, concave from above 
downward, is smooth, and affords attachment on each side to the Pectoralis major 
and sternal origin of the Sterno-cleido-mastoid muscle. In well-marked bones the 
ridges limiting the attachment of these muscles are very distinct. Its posterior 
surface, concave and smooth, affords attachment on each side to the Sterno-hyoid 
and Sterno-thyroid muscles. The superior border, the thickest, presents at its 
centre the inter clavicular notch, and on each side an oval articular surface, directed 
upward, backward, and outward, for articulation with the sternal end of the clavicle. 
The inferior border presents an oval rough surface, covered in the recent state with 
a thin layer of cartilage, for articulation with the second portion of the bone. The 
lateral borders are marked above by an articular depression for the first costal carti- 
lage, and below by a small facet, which, with a similar facet on the upper angle of 
the middle portion of the bone, forms a notch for the reception of the costal carti- 
lage of the second rib. These articular surfaces are separated by a narrow curved 
edge which slopes from above downward and inward. [The interclavicular notch 
and the sternal ends of the clavicles will well repay study in the living model.] 
The Second Piece of the sternum, or Gladiolus (mesosternum), considerably 
longer, narrower, and thinner than the first piece, is broader below than above. 
Its anterior surface is nearly flat, directed upward and forward, and marked by 
three transverse lines which cross the bone opposite the third, fourth, and fifth 
articular depressions. These lines are produced by the union of the four separate 
pieces, of which this part of the bone consists at an early period of life. At the 
junction of the third and fourth pieces is occasionally seen an orifice, the sternal 
foramen ; it varies in size and form in different individuals, and pierces the bone 
from before backward. This surface affords attachment on each side to the sternal 
origin of the Pectoralis major. The posterior surface, slightly concave, is also 
marked by three transverse lines, but they are less distinct than those in front: 
this surface affords attachment below, on each side, to the Triangularis sterni 
muscle, and occasionally presents the posterior opening of the sternal foramen. 
The superior border presents an oval surface for articulation with the manubrium. 
The inferior border is narrow and articulates with the ensiform appendix. Each 
lateral border presents at each superior angle a small facet, which, with a similar 
facet on the manubrium, forms a cavity for the cartilage of the second rib ; the 
four succeeding angular depressions receive the cartilages of the third, fourth, fifth, 
and sixth ribs, while each inferior angle presents a small facet, which, with a cor- 
responding one on the ensiform appendix, forms a notch for the cartilage of the 
seventh rib. These articular depressions are separated by a series of curved inter- 
articular intervals, which diminish in length from above downward, and correspond 
to the intercostal spaces. Most of the cartilages belonging to the true ribs, as will 
be seen from the foregoing description, articulate with the sternum at the line of 
junction of two of its primitive component segments. This is well seen in many 
of the lower animals, where the separate parts of the bone remain ununited longer 
than in man. In this respect a striking analogy exists between the mode of con- 
nection of the ribs with the vertebral column and the connection of their cartilages 
with the sternal column. 
The Third Piece of the sternum, the Ensiform or Xiphoid Appendix (meta- THE STERNUM. 
223 
sternum), is the smallest of 
the three ; it is thin and elon- 
gated in form, cartilaginous in 
structure in youth, but more 
or less ossified at its upper 
part in the adult. Its ante- 
rior surface affords attach- 
ment to the costo-xiphoid 
ligament; its posterior sur- 
face, to some of the fibres 
of the Diaphragm and Tri- 
angularis sterni muscles; its 
lateral borders, to the apon- 
eurosis of the abdominal mus- 
cles. Above, it is continuous 
with the lower end of the 
gladiolus; below, by its point- 
ed extremity, it gives attach- 
ment to the linea alba, and at 
each superior angle presents a 
facet for the lower half of the 
cartilage of the seventh rib. 
This portion of the sternum is 
very various in appearance, be- 
ing sometimes pointed, broad 
and thin, sometimes bifid or 
perforated by a round hole, 
occasionally curved or deflect- 
ed considerably to one or the 
other side. 
Structure.-The bone is 
composed of delicate cancel- 
lated texture, covered by a thin 
layer of compact tissue, which 
is thickest in the manubrium, 
between the articular facets for 
the clavicles. 
Development.-The ster- 
num, including the ensiform 
appendix, is developed by six 
centres; one for the first piece, 
or manubrium, four for the 
second piece, or gladiolus, and 
one for the ensiform appendix. 
Up to the middle of foetal life 
the sternum is entirely carti- 
laginous, and when ossification 
takes place the ossific granules 
are deposited in the middle of 
the intervals between the ar- 
ticular depressions for the cos- 
tal cartilages, in the following 
order (Fig. 186): In the first 
piece, between the fifth and 
sixth months; in the second 
and third, between the sixth 
and seventh months; in the 
Fig. 188. 
1for Doe [5-6 mo.fatal 
or Ndnulriu/m 
T imt 
App & ar a, no c 
2 1 
I 6~7 mo. 
3 I ' 
gib mo. 
5 . 1-bipafln 
airt/i 
or 
Gladiolus 
ffor Ensiform 
' Cartilage 
y-t- 
Development of the Sternum, by six centres. 
Fig. 189. 
rccreby unite , 
except inoZolaye 
35-1,0. 
20-25?b yea r 
soon afterpuberty 
Tom e 
°f 
Union 
partly cartilaginous in, 
advanced life 
Fig. 190. 
for 1-1 piece Zor more centres 
Z-'Spiece, usually one 
Peculiarities 
In 
num b or of 
Contns 
3 
, 
2placed laterally 
Fig. 191. 
And in 
Mode of 
Union ■ 
Arrest of Renelojjment 
of lateralpieces producino/ 
-Sternal fissure Sc 
-Sternal foramen 224 
THE SKELETON. 
Fig. 192. 
fourth piece, at the ninth month ; in the fifth, within 
the first year, or between the first and second years 
after birth; and in the ensiform appendix, between 
the second and the seventeenth or eighteenth years 
by a single centre which makes its appearance at 
the upper part and proceeds gradually downward. 
To these may be added the occasional existence, as 
described by Breschet, of two small episternal cen- 
tres, which make their appearance one on each side 
of the interclavicular notch. These are regarded by 
him as the anterior rudiments of a rib, of which the 
posterior rudiment is the anterior lamina of the trans- 
verse process of the seventh cervical vertebra. It 
occasionally happens that some of the segments are 
formed from more than one centre, the number and 
position of which vary (Fig. 190). Thus the first 
piece may have two, three, or even six centres. 
When two are present, they are generally situated 
one above the other, the upper one being the larger ;* 
the second piece has seldom more than one; the third, 
fourth, and fifth pieces are often formed from two cen- 
tres placed laterally, the irregular union of which will 
serve to explain the occasional occurrence of the ster- 
nal foramen (Fig. 191), or of the vertical fissure which 
occasionally intersects this part of the bone. Union 
of the various centres commences from below and 
proceeds upward, taking place in the following- 
order (Fig. 189): The fifth piece is joined to the 
fourth soon after puberty; the fourth to the third, 
between the twentieth and twenty-fifth years; the 
third to the second, between the thirty-fifth and 
fortieth years; the second is occasionally joined to 
the first, especially at an advanced age. 
Articulations.-With the clavicles and seven 
costal cartilages on each side. 
Attachment of Muscles.-To nine pairs and 
one single muscle: the Pectoralis major, Sterno- 
cleido-mastoid, Sterno-hyoid, Sterno-thyroid, Trian- 
gularis sterni, aponeuroses of the Obliquus externus, 
Obliquus internus, and Transversalis muscles, Rec- 
tus, and Diaphragm. 
The Ribs. 
The Ribs are elastic arches of bone which form 
the chief part of the thoracic walls. They are twelve 
in number on each side, but this number may be in- 
creased by the development of a cervical or lumbar 
rib, or may be diminished to eleven. The first seven 
are connected behind with the spine, and in front 
with the sternum, through the intervention of the 
costal cartilages; they are called vertebrosternal, or 
true ribs. The remaining five are false ribs: of these 
the first three, being connected behind with the spine, 
and in front with the costal cartilages, are usually 
called the vertebro-costal, but would be better named 
A Central Rib of Right Side, inner 
surface. 
1 Professor Humphry states that this is "probably the more complete condition." THE RIBS. 
225 
the vertebro-chondral ribs; the last two are connected with the vertebrae only, being 
free at their anterior extremities; they are termed vertebral or floating ribs. The 
ribs vary in their direction, the upper ones being placed nearly at right angles 
with the spine, the lower ones obliquely, so that the anterior extremity is lower than 
the posterior. The extent of obliquity reaches its maximum at the ninth rib, and 
gradually decreases from that rib to the twelfth. The ribs are situated one below 
the other in such a manner that spaces are left between them, which are called inter- 
costal spaces. Their length corresponds to the length of the ribs ; their breadth is 
more considerable in front than behind, and between the upper than between the 
lower ribs. The ribs increase in length from the first to the seventh, when they 
again diminish to the twelfth. In breadth they decrease from above downward; in 
the upper ten the greatest breadth is at the sternal extremity. 
Common Characters of the Ribs (Fig. 192).-A rib from the middle of the 
series should be taken in order to study the common characters of the ribs. 
Each rib presents two extremities, a posterior or vertebral, an anterior or ster- 
nal, and an intervening portion-the body or shaft. The posterior or vertebral 
extremity presents for examination a head, neck, and tuberosity. The head (Fig. 
193) is marked by a kidney-shaped articular surface, divided by a horizontal ridge 
into two facets for articulation with the costal cavity formed by the junction of the 
Fig. 193. 
facet for body of upper Dor sal 
far Ant- Cnsto-tTU.vrTjlp 
for pvstX Custo-transverse Liy* 
dtidijc for Inter-articular Lip- 
facet for body of lower Dorsal Vert®. 
for tra-iisv. proc. of lower 
Vertebral Extremity of a Rib, external surface. 
bodies of two contiguous dorsal vertebrae; the upper facet is small, the inferior one 
of large size; the ridge separating them serves for the attachment of the interar- 
ticular ligament. 
The neck is that flattened portion of the rib which extends outward from the 
head; it is about an inch long, and rests upon the transverse process of the lower 
of the two vertebrae with which the head articulates. Its anterior surface is flat 
and smooth, its posterior rough, for the attachment of the middle costo-transverse 
ligament, and perforated by numerous foramina, the direction of which is less con- 
stant than those found on the inner surface of the shaft. Of its two borders, the 
superior presents a rough crest, for the attachment of the anterior costo-transverse 
ligament; its inferior border is rounded. On the posterior surface of the neck, 
just where it joins the shaft, and nearer the lower than the upper border, is an 
eminence-the tuberosity, or tubercle; it consists of an articular and a non- 
articular portion. The articular portion, the more internal and inferior of the 
two, presents a small oval surface, for articulation with the extremity of the trans- 
verse process of the lower of the two vertebrae to which the head is connected. 
The non-articular portion is a rough elevation which affords attachment to the 
posterior costo-transverse ligament. The tubercle is much more prominent in the 
upper than in the lower ribs. 
The shaft is thin and flat, so as to present two surfaces, an external and an 
internal; and two borders, a superior and an inferior. The external surface is 
convex, smooth, and marked at its back part, a little in front of the tuberosity, by 
a prominent line directed obliquely from above downward and outward; this gives 
attachment to a tendon of the Sacro-lumbalis muscle or of one of its accessory por- 
tions, and is called the angle. At this point the rib is bent in two directions. If 
the rib is laid upon its lower border, it will be seen that the anterior portion of the 226 
THE SKELETON. 
shaft, as far as the angle, rests upon this margin, while the vertebral end of the 
bone, beyond the angle, is bent inward and at the same time tilted upward. The 
interval between the angle and the tuberosity increases gradually from the second 
to the tenth rib. The portion of the bone between these two parts is rounded, rough, 
and irregular, and serves for the attachment of the Longissimus dorsi. The por- 
tion of bone between the tubercle and sternal extremity is also slightly twisted 
upon its own axis, the external surface looking downward behind the angle, a little 
upward in front of it. This surface presents, toward its sternal extremity, an 
oblique line, the anterior angle. The internal surface is concave, smooth, directed 
a little upward behind the angle, a little downward in front of it. This surface is 
marked by a ridge which commences at the lower extremity of the head; it is 
strongly marked as far as the inner side of the angle, and gradually becomes lost at 
the junction of the anterior with the middle third of the bone. The interval 
between it and the inferior border is deeply grooved, to lodge the intercostal vessels 
and nerve. At the back part of the bone this groove belongs to the inferior bor- 
der, but just in front of the angle, where it is deepest and broadest, it corresponds 
to the internal surface. The superior edge of the groove is rounded; it serves for 
the attachment of the Internal intercostal muscle. The inferior edge corresponds 
to the lower margin of the rib, and gives attachment to the External intercostal. 
Within the groove are seen the orifices of numerous small foramina which traverse 
the wall of the shaft obliquely from before backward. The superior border, thick 
and rounded, is marked by an external and an internal lip, more distinct behind 
than in front; they serve for the attachment of the External and Internal inter- 
costal muscles. The inferior border, thin and sharp, has attached the External 
intercostal muscle. The anterior or sternal extremity is flattened, and presents 
a porous, oval, concave depression into which the costal cartilage is received. 
[Most of the ribs can readily be studied in the living model by his raising his 
arms and then breathing deeply. In great exertion the ribs are elevated and fixed 
in inspiration, to give a firm point d'appui to the muscles of the arms, as Bell 
has well illustrated in the Anatomy of Expression, Essay viii.] 
Peculiar Ribs. 
The ribs which require especial consideration are five in number-viz. the first;, 
second, tenth, eleventh, and twelfth. 
The first rib (Fig. 194) is one of the shortest and the most curved of all the 
ribs; it is broad, flat, and placed horizontally at the upper part of the thorax, its 
surfaces looking upward and downward, and its borders inward and outward. The 
head is of small size, rounded, and presents only a single articular facet for articu- 
lation with the body of the first dorsal vertebra. The neck is narrow and rounded. 
The tuberosity, thick and prominent, rests on the outer border. There is no angle, 
but in this situation the rib is slightly bent, with the convexity of the bend upward, 
so that the head of the bone is directed downward. The upper surface of the shaft 
is marked by two shallow depressions, separated from one another by a ridge, which 
becomes more prominent toward the internal border, where it terminates in a tuber- 
cle : this tubercle and ridge serve for the attachment of the Scalenus anticus mus- 
cle, the groove in front of it transmitting the subclavian vein; that behind it, the 
subclavian artery. Between the groove for the subclavian artery and the tuberosity 
is a depression, for the attachment of the Scalenus medius muscle. The under sur- 
face is smooth, and destitute of the groove observed on the other ribs. The outer 
border is convex, thick, and rounded, and at its posterior part gives attachment to 
the first serration of the Serratus magnus; the inner, concave, thin, and sharp, and 
marked about its centre by the tubercle before mentioned. The internal extremity 
is larger and thicker than that of any of the other ribs. 
The second rib (Fig. 195) is much longer than the first, but bears a very con- 
siderable resemblance to it in the direction of its curvature. The non-articular 
portion of the tuberosity is occasionally only slightly marked. The anyle is slight, PECULIAR RIBS. 
227 
and situated close to the tuberosity, and the shaft is not twisted, so that both ends 
touch any plane surface upon which it may be laid; but there is a similar though 
slighter bend, with its convexity upward, to that found in the first rib. The shaft 
is not horizontal, like that of the first rib, its outer stirface, which is convex, look- 
ing upward and a little outward. It presents, near the middle, a rough eminence, 
for the attachment of the second and third digitations of the Serratus magnus, 
Figs. 194-198. 
Fig. 194. 
Fig. 195. 
.Angle,- , 
SligJitlg'mtirJtcil 
& close to tule/rosity 
Fig. 196. 
Single u/rticAila/r ftctJt 
Fig. 197. 
frin'jlt artie. facet - 
Fig. 198. 
Single ar tic. fac. 
Peculiar Ribs. 
behind and above which is attached the Scalenus posticus. The inner surface, 
smooth and concave, is directed downward and a little inward: it presents a short 
groove toward its posterior part. 
The tenth rib (Fig. 196) has only a single articular facet on its head. 
The eleventh and twelfth ribs (Figs. 197 and 198) have each a single articular 
facet on the head, which is of rather large size; they have no neck or tuberosity, 228 
THE SKELETON. 
and are pointed at the extremity. The eleventh has a slight angle and a shallow 
groove on the lower border. The twelfth has neither, and is much shorter than the 
eleventh, and the head has a slight inclination downward. 
Structure.-The ribs consist of cancellous tissue enclosed in a thin compact layer. 
Development.-Each rib, with the exception of the last two, is developed by 
three centres: one for the shaft, one for the head, and one for the tubercle. The 
last two have only two centres, that for the tubercle being wanting. Ossification 
commences in the body of the ribs at a very early period, before its appearance in 
the vertebrae. The epiphysis of the head, which is of a slightly angular shape, and 
that for the tubercle, of a lenticular form, make their appearance between the six- 
teenth and twentieth years, and are not united to the rest of the bone until about 
the twenty-fifth year. 
Attachment of Muscles.-To twenty: the Internal and External Intercostals, 
Scalenus anticus, Scalenus medius, Scalenus posticus, Pectoralis minor, Serratus 
magnus, Obliquus externus, Transversalis, Quadratus lumborum, Diaphragm, Latis- 
simus dorsi, Serratus posticus superior, Serratus posticus inferior, Sacro-lumbalis, 
Musculus accessorius ad sacro-lumbalem, Longissimus dorsi, Cervicalis ascendens, 
Levatores costarum, and Infracostales. 
The Costal Cartilages. 
The Costal Cartilages (Fig. 186, p. 221) are white elastic structures, which 
serve to prolong the ribs forward to the front of the chest and contribute very 
materially to the elasticity of its walls. The first seven are connected with the 
sternum; the next three with the lower border of the cartilage of the preceding rib. 
The cartilages of the last two ribs, which have proper extremities, float freely in 
the walls of the abdomen. Like the ribs, the costal cartilages vary in their length, 
breadth, and direction. They increase in length from the first to the seventh, then 
gradually diminish to the last. They diminish in breadth, as well as the intervals 
between them, from the first to the last. They are broad at their attachment to the 
ribs, and taper toward their sternal extremities, excepting the first two, which are 
of the same breadth throughout, and the sixth, seventh, and eighth, which are 
enlarged where their margins are in contact. In direction they also vary: the first 
descends a little, the second is horizontal, the third ascends slightly, whilst all the 
rest follow the course of the ribs for a short extent, and then ascend to the sternum 
or preceding cartilage. Each costal cartilage presents two surfaces, two borders, and 
two extremities. The anterior surface is convex, and looks forward and upward; 
that of the first gives attachment to the costo-clavicular ligament and the Subcla- 
vius muscle; that of the second, third, fourth, fifth, and sixth, at their sternal ends, 
to the Pectoralis major.1 The others are covered by, and give partial attachment 
to, some of the great flat muscles of the abdomen. The posterior surface is concave 
and directed backward and downward, the first giving attachment to the Sterno- 
thyroid, and the six or seven inferior ones affording attachment to the Transversal is 
muscle and the Diaphragm. Of the two borders, the superior is concave, the infe- 
rior convex : they afford attachment to the Intercostal muscles, the upper border of 
the sixth giving attachment to the Pectoralis major muscle. The contiguous bor- 
ders of the sixth, seventh, and eighth costal cartilages, and sometimes the ninth and 
tenth, present smooth, oblong surfaces at the points where they articulate. Of the 
two extremities, the outer one is continuous with the osseous tissue of the rib to 
which it belongs. The inner extremity of the first is continuous with the sternum; 
the six succeeding ones have rounded extremities, which are received into shallow 
concavities on the lateral margins of the sternum. The inner extremities of the 
eighth, ninth, and tenth costal cartilages are pointed, and are connected with the 
cartilage above. Those of the eleventh and twelfth are free and pointed. 
The costal cartilages are most elastic in youth, those of the false ribs being more 
so than the true. In old age they become of a deep yellow color. Under certain 
1 The first and seventh also occasionally give origin to the same muscle. THE EXTREMITIES. 
229 
diseased conditions they are prone to ossify. Dr. Humphry's observations on this 
subject have led him to regard the ossification of the costal cartilages as a sign of 
disease rather than of age : " The ossification takes place in the first cartilage sooner 
than in the others; and in men more frequently, and at an earlier period of life, 
than in women." 
Attachment of Muscles.-To nine: the Subclavius, Sterno-thyroid, Pector- 
alis major, Internal oblique, Transversalis, Rectus, Diaphragm, Triangularis sterni, 
and Internal Intercostals. 
OF THE EXTREMITIES. 
The extremities, or limbs, are those long, jointed appendages of the body which 
are connected to the trunk by one end and free in the rest of their extent. They 
are four in number: an upper or thoracic pair, connected with the thorax through 
the intervention of the shoulder, and subservient mainly to prehension; and a 
lotver pair, connected with the pelvis, intended for support and locomotion. Both 
pairs of limbs are constructed after one common type, so that they present numer- 
ous analogies, while at the same time certain differences are observed in each, 
dependent on the peculiar offices they have to perform. 
Of the Upper Extremity. 
The upper extremity consists of the arm, the forearm, and the hand. Its con- 
tinuity with the trunk is established by means of the shoulder, which is homologous 
with the innominate or haunch-bone in the lower limb. [For a comparison of the 
shoulder girdle with the pelvic girdle, see p. 259.] 
Of the Shoulder. 
The Shoulder is placed upon the upper part and side of the chest, connecting 
the upper extremity to the trunk ; it consists of two bones-the clavicle and the 
scapula. [The inner end of the clavicle is the only point at wThich the upper 
extremity has any bony connection whatever with the trunk, the scapula being- 
attached to the trunk wholly by muscles. It is accordingly the pivot on which the 
upper extremity, as a whole, moves. The range of motion of the clavicle, especially 
in the vertical direction, is very large, and is well shown on the model by comparing 
the two clavicles while he shrugs one shoulder. The frequent fracture of the 
clavicle by indirect violence, as by falls on the hand, etc., is also due to its being 
the only bony means of uniting the upper extremity to the trunk.] 
The Clavicle {ciavis, a key), or collar-bone, forms the anterior portion of the 
shoulder-girdle. It is a long bone, curved somewhat like the italic letter/, and 
placed nearly horizontally at the upper and anterior part of the thorax, immediately 
above the first rib. It articulates by its inner extremity with the upper border of 
the sternum, and by its outer extremity with the acromion process of the scapula, 
serving to sustain the upper extremity in the various positions which it assumes, 
whilst at the same time it allows of great latitude of motion in the arm.1 In women 
the clavicle is almost if not quite horizontal; but in men it inclines [slightly] down- 
ward to the sternum. It presents a double curvature when looked at in front, the 
convexity being forward at the sternal end, and the concavity at the scapular end. 
The Clavicle. 
1 The clavicle acts especially as a fulcrum to enable the muscles to give lateral motion to the arm. 
It is accordingly absent in those animals whose fore limbs are used only for progression, but is pres- 
ent for the most part in those animals whose anterior extremities are clawed and used for prehension, 
though in some of them-as, for instance, in a large number of the Carnivora-it is merely a rudi- 
mentary bone suspended among the muscles, and not articulating either with the scapula or sternum. 230 
THE SKELETON. 
Its outer third is flattened from above downward, and extends, in the natural posi- 
tion of the bone, from a point opposite the coracoid process to the acromion. Its 
inner two-thirds are of a cylindrical form, and extend from the sternum to a point 
opposite the coracoid process of the scapula. 
External or Flattened Portion.-The outer third is flattened from above down- 
ward, so as to present two surfaces, an upper and a lower ; and two borders, an ante- 
rior and a posterior. The upper surface is flattened, rough, marked by impressions 
for the attachment of the Deltoid in front and the Trapezius behind: between these 
two impressions, externally, a small portion of the bone is subcutaneous. The 
under surface is flattened. At its posterior border, where the prismatic joins with 
the flattened portion, is a rough eminence, the conoid tubercle ; this in the natural 
position of the bone surmounts the coracoid process of the scapula and gives attach- 
ment to the conoid ligament. From this tubercle an oblique line, occasionally a 
depression, passes forward and outward to near the outer end of the anterior bor- 
der ; it is called the oblique line, and affords attachment to the trapezoid ligament. 
The anterior border is concave, thin, and rough ; it limits the attachment of the 
Deltoid, and occasionally presents, near the centre, a tubercle, the deltoid tubercle, 
which is sometimes distinct in the living subject. The posterior border is convex, 
rough, broader than the anterior, and gives attachment to the Trapezius. 
Internal or Cylindrical Portion.-The cylindrical portion forms the inner two- 
thirds of the bone. It is curved, so as to be convex in front, concave behind, and 
is marked by three borders separating three surfaces. The anterior border is con- 
tinuous with the anterior margin of the flat portion. At its commencement it is 
smooth, and corresponds to the interval between the attachment of the Pectoralis 
major and Deltoid muscles; at the inner half of the clavicle it forms the lower 
boundary of an elliptical space for the attachment of the clavicular portion of the 
Pectoralis major, and approaches the posterior border of the bone. The superior 
border is continuous with the posterior margin of the flat portion, and separates the 
anterior from the posterior surface. At its commencement it is smooth and rounded, 
becomes rough toward the inner third for the attachment of the Sterno-mastoid 
muscle, and terminates at the upper angle of the sternal extremity. The joosterzor 
or subclavian border separates the posterior from the inferior surface, and extends 
from the conoid tubercle to the rhomboid impression. It forms the posterior bound- 
ary of the groove for the Subclavius muscle, and gives attachment to the fascia 
which encloses that muscle. The anterior surface is included between the superior 
and anterior borders. It is directed forward and a little upward at the sternal end, 
outward and still more upward at the acromial extremity, where it becomes continu- 
ous with the upper surface of the flat portion. Externally, it is smooth, convex, 
nearly subcutaneous, being covered only by the Platysma; but, corresponding to 
the inner half of the bone, it is divided by a more or less prominent line into two 
parts-a lower portion, elliptical in form, rough, and slightly convex, for the 
attachment of the Pectoralis major; and an upper part, which is rough behind, for 
the attachment of the Sterno-cleido-mastoid. Between the two muscular impres- 
sions is a small subcutaneous interval. The posterior or cervical surface is smooth, 
flat, directed vertically, and looks backward toward the root of the neck. It is 
limited above by the superior border; below, by the subclavian border; internally, 
by the margin of the sternal extremity; externally, it is continuous with the poste- 
rior border of the flat portion. It is concave from within outward, and is in rela- 
tion, by its lower part, with the suprascapular vessels. This surface, at about the 
junction of the inner and outer curves, is also in close relation with the brachial 
plexus and subclavian vessels, which may be injured in fracture of the bone at this 
part. It gives attachment, near the sternal extremity, to part of the Sterno-hyoid 
muscle; and presents, at or near the middle, a foramen, directed obliquely outward, 
which transmits the chief nutrient artery of the bone. Sometimes there are two for- 
amina on the posterior surface, or one on the posterior, the other on the inferior sur- 
face. The inferior or subclavian surface is bounded in front by the anterior border; 
behind, by the subclavian border. It is narrow internally, but gradually increases THE CLAVICLE. 
231 
in width externally, and is continuous with the under surface of the flat portion. 
Commencing at the sternal extremity may be seen a small facet for articulation with 
the cartilage of the first rib. This is continuous with the articular surface at the 
sternal end of the bone. External to this is a broad rough impression, the rhomboid, 
rather more than an inch in length, for the attachment of the costo-clavicular (rhom- 
boid) ligament. The remaining part of this surface is occupied by a longitudinal 
groove, the subclavian groove, broad and smooth externally, narrow and more 
uneven internally; it gives 'attachment to the Subclavius muscle, and by its ante- 
rior margin to the strong aponeurosis which encloses it. Not unfrequently this 
groove is subdivided into two parts by a longitudinal line, which gives attachment 
to the intermuscular septum of the Subclavius muscle. 
The internal or sternal end of the clavicle is triangular in form, directed inward 
and a little downward and forward, and presents an articular facet, concave from 
before backward, convex from above downward, which articulates with the sternum 
through the intervention of an interarticular fibro-cartilage; the circumference of 
the articular surface is rough, for the attachment of numerous ligaments. The pos- 
terior border of this surface is prolonged backward, so as to increase the size of the 
articular facet; the upper border gives attachment to the interarticular fibro-carti- 
Fig. 199. 
Sl'erntil 
Acromial JZxty 
Left Clavicle, anterior surface. 
Fig. 200. 
Left Clavicle, inferior surface. 
lage, and the lower border is continuous with the costal facet on the inner end of 
the inferior or subclavian surface, which articulates with the cartilage of the first rib. 
The outer or acromial extremity, directed outward and forward, presents a 
small, flattened, oval facet which looks obliquely downward, for articulation with 
the acromion process of the scapula. The direction of this surface serves to explain 
the greater frequency of dislocation upward rather than downward beneath the 
acromion process. The circumference of the articular facet is rough, especially 
above, for the attachment of the acromio-clavicular ligaments. 
Peculiarities of the Bone in the Sexes and in Individuals.-In the female the 
clavicle is generally less curved, smoother, and more slender than in the male. It 
is also somewhat shorter. In those persons who perform considerable manual labor, 
which brings into constant action the muscles connected with this bone, it acquires 232 
THE SKELETON. 
considerable bulk, becomes thicker, more curved, its ridges for muscular attach- 
ment become prominently marked, and its sternal end of a prismatic form. The 
right clavicle is generally heavier, thicker, and rougher, and often shorter, than 
the left. 
Structure.-The shaft, as well as the extremities, consists of cancellous tissue, 
invested in a compact layer much thicker in the middle than at either end. The 
clavicle is highly elastic, by reason of its curves. From the experiments of Mr. 
Fig. 201. 
Ward it has been shown that it possesses sufficient longitudinal elastic force to pro- 
ject its own weight nearly two feet on a level surface when a smart blow is struck 
on it, and sufficient transverse elastic force, opposite the centre of its anterior con- 
vexity, to throw its own weight about a foot. This extent of elastic power must 
serve to moderate very considerably the effect of concussions received upon the 
point of the shoulder. 
Development.-By two centres: one for the shaft, and one for the sternal 
Left Scapula, anterior surface, or venter. THE SCAPULA. 
233 
extremity. The centre for the shaft appears very early, before any other bone; 
according to as early as the thirtieth day. The centre for the sternal end 
makes its appearance about the eighteenth or twentieth year, and unites with the 
rest of the bone about the twenty-fifth year. 
Articulations.-With the sternum, scapula, and cartilage of the first rib. 
Attachment of Muscles.-To seven: the Sterno-cleido-mastoid, Trapezius, 
Pectoralis major, Deltoid, Subclavius, Sterno-hyoid, and Platysma. 
The Scapula. 
The Scapula (axandvv], a spade) forms the back part of the shoulder. It is a 
large flat bone, triangular in shape, situated at the posterior aspect and side of the 
thorax, between the first and eighth ribs, its posterior border or base being about 
an inch from, and nearly parallel with, the spinous process of the vertebrae. [For 
the study of its movements, see the Shoulder-joint.] It presents for examination 
two surfaces, three borders, and three angles. 
The anterior surface or venter (Fig. 201) presents a broad concavity, the sub- 
scapular fossa. It is marked in the posterior two-thirds by several oblique ridges, 
which pass from behind obliquely outward and upward, the anterior third being 
smooth. The oblique ridges give attachment to the tendinous intersections, and the 
surfaces between them to the fleshy fibres, of the Subscapularis muscle. The ante- 
rior third of the fossa, which is smooth, is covered by, but does not afford attach- 
ment to, the fibres of this muscle. This surface is separated from the posterior 
border by a smooth triangular margin at the superior and inferior angles, and in 
the interval between these by a narrow edge which is often deficient. This marginal 
surface affords attachment throughout its entire extent to the Serratus magnus mus- 
cle. The subscapular fossa presents a transverse depression at its upper part, where 
the bone appears to be bent on itself, forming a considerable angle, called the sub- 
scapular angle, thus giving greater strength to the body of the bone from its arched 
form, while the summit of the arch serves to support the spine and acromion process. 
It is in this situation that the fossa is deepest, so that the thickest part of the Sub- 
scapularis muscle lies in a line perpendicular to the plane of the glenoid cavity, and 
must consequently operate most effectively on the head of the humerus, which is 
contained in that cavity. 
The posterior surface, or dorsum (Fig. 202), is arched from above downward, 
alternately concave and convex from side to side. It is subdivided unequally into 
two parts by the spine: the portion above the spine is called the supraspinous 
fossa, and that below it the infraspinous fossa. 
The supraspinous fossa, the smaller of the two, is concave, smooth, and 
broader at the vertebral than at the humeral extremity. It affords attachment 
by its inner two-thirds to the Supraspinatus muscle. 
The infraspinous fossa is much larger than the preceding; toward its vertebral 
margin a shallow concavity is seen at its upper part; its centre presents a promi- 
nent convexity, whilst toward the axillary border is a deep groove which runs from 
the upper toward the lower part. The inner two-thirds of this surface afford attach- 
ment to the Infraspinatus muscle; the outer third is only covered by it, without 
giving origin to its fibres. This surface is separated from the axillary border by an 
elevated ridge, which runs from the lower part of the glenoid cavity downward and 
backward to the posterior border, about an inch above the inferior angle. The ridge 
serves for the attachment of a strong aponeurosis which separates the Infraspinatus 
from the two Teres muscles. The surface of bone between this line and the axillary 
border is narrow in the upper two-thirds of its extent, and traversed near its centre 
by a groove for the passage of the dorsalis scapulae vessels; it affords attachment to 
the Teres minor. Its lower third presents a broader, somewhat triangular surface, 
which gives origin to the Teres major, and over which the Latissimus dorsi glides; 
sometimes the latter muscle takes origin by a few fibres from this part. The broad 
and narrow portions of bone above alluded to are separated by an oblique line which 234 
THE SKELETON. 
runs from the axillary border downward.and backward: to it is attached the aponeur- 
osis separating the two Teres muscles from each other. 
The Spine is a prominent plate of bone which crosses obliquely the inner four- 
fifths of the dorsum of the scapula at its upper part, and separates the supra- from 
the infra-spinous fossa. [It is always easily felt directly under the skin, and in 
Fig. 202. 
Left Scapula, posterior surface, or dorsum. 
muscular models is a linear depression between the attachments of the Trapezius 
and the Deltoid.] It commences at the vertebral border by a smooth triangular 
surface, over which the Trapezius glides, separated from the bone by a bursa; [in 
the living model, when the muscles are called into action, this triangle is marked 
by a deep fossa], and gradually becoming more elevated as it passes forward, termi- 
nates in the acromion process, which overhangs the shoulder-joint. The spine is 
triangular and flattened from above downward, its apex corresponding to the pos- 
terior border; its base, which is directed outward, to the neck of the scapula. It THE SCAPULA. 
235 
presents two surfaces and three borders. Its superior surface is concave, assists in 
forming the supraspinous fossa, and affords attachment to part of the Supraspinatus 
muscle. Its inferior surface forms part of the infraspinous fossa, gives origin to part 
of the Infraspinatus muscle, and presents near its centre the orifice of a nutrient canal. 
Of the three borders, the anterior is attached to the dorsum of the bone; the poste- 
rior, or crest of the spine, is broad and presents two lips and an intervening rough 
interval. To the superior lip is attached the Trapezius, to the extent shown in the 
figure. A very rough tubercle is generally seen occupying that portion of the spine 
which receives the insertion of the middle and inferior fibres of this muscle. To 
the inferior lip, throughout its whole length, is attached the Deltoid. The interval 
between the lips is also partly covered by the fibres of these muscles. The external 
border, the shortest of the three, is slightly concave, its edges thick and round, con- 
tinuous above with the under surface of the acromion process ; below, with the neck 
of the scapula. The narrow portion of bone external to this border serves to connect 
the supra- and infra-spinous fossae. 
The Acromion Process, so called from forming the summit of the shoulder 
(dxpov, a summit; duo', the shoulder), is a large and somewhat triangular process, 
flattened from behind forward, directed at first a little outward, and then curving 
forward and upward, so as to overhang the glenoid cavity. Its upper surface, 
directed upward, backward, and outward, is convex, rough, and gives attachment 
to some fibres of the Deltoid and the Platysma, and in the rest of its extent it is 
subcutaneous. Its under surface is smooth and concave. Its outer border, which 
is thick and irregular, affords attachment to the Deltoid muscle. Its inner margin, 
shorter than the outer, is concave, gives attachment to a portion of the Trapezius 
muscle, and presents about its centre a small oval surface for articulation with the 
acromial end of the clavicle. Its apex, which corresponds to the point of meeting 
of these two borders in front, is thin, and has attached to it the coraco-acromial 
ligament. 
Of the three borders or costae of the scapula, the superior is the shortest and 
thinnest; it is concave, terminating at its inner extremity at the superior angle, at 
its outer extremity at the coracoid process. At its outer part is a deep semicircu- 
lar notch, the suprascapular, formed partly by the base of the coracoid process. 
This notch is converted into a foramen by the transverse ligament [which is occa- 
sionally ossified], and serves for the passage of the suprascapular nerve. The 
adjacent margin of the superior border affords attachment to the Omo-hyoid mus- 
cle. The external, or axillary, border is the thickest of the three. It commences 
above at the lower margin of the glenoid cavity, and inclines obliquely downward 
and backward to the inferior angle. Immediately below the glenoid cavity is a 
rough impression, about an inch in length, which affords attachment to the long 
head of the Triceps muscle; to this succeeds a longitudinal groove which extends 
as far as its lower third and affords origin to part of the Subscapularis muscle. 
The inferior third of this border, which is thin and sharp, serves for the attach- 
ment of a few fibres of the Teres major behind and of the Subscapularis in front. 
The internal, or vertebral, border, also named the base, is the longest of the three, 
and extends from the superior to the inferior angle of the bone. It is arched, 
intermediate in thickness between the superior and the external borders, and the 
portion of it above the spine is bent considerably outward, so as to form an obtuse 
angle with the lower part. The vertebral border presents an anterior lip, a poste- 
rior lip, and an intermediate space. The anterior lip affords attachment to the 
Serratus magnus; the posterior lip, to' the Supraspinatus above the spine, the 
Infraspinatus below; the interval between the two lips, to the Levator anguli 
scapulae above the triangular surface at the commencement of the spine; the 
Rhomboideus minor, to the edge of that surface, the Rhomboideus major being 
attached by means of a fibrous arch, connected above to the lower part of the tri- 
angular surface at the base of the spine and below to the lower part of the poste- 
rior border. 
Of the three angles, the superior, formed by the junction of the superior and 236 
THE SKELETON. 
internal borders, is thin, smooth, rounded, somewhat inclined outward, and gives 
attachment to a few fibres of the Levator anguli scapulae muscle. The inferior 
angle, thick and rough, is formed by the union of the vertebral and axillary bor- 
ders, its outer surface affording attachment to the Teres major, and occasionally a 
few fibres of the Latissimus dorsi. The anterior angle is the thickest part of the 
bone, and forms what is called the head of the scapula. The head presents a shal- 
low, pyriform, articular surface, the glenoid cavity a socket), whose longest 
diameter is from above downward, and its direction outward and forward. It is 
broader below than above: at its apex is attached the long tendon of the Biceps 
muscle. It is covered with cartilage in the recent state; and its margins, slightly 
raised, give attachment to a fibro-cartilaginous structure, the glenoid ligament, by 
which its cavity is deepened. The neck of the scapula is the slightly depressed 
surface which surrounds the head; it is more distinct on the posterior than on the 
anterior surface, and below than above. In the latter situation it has arising from 
it a thick prominence, the coracoid process. 
The Coracoid Process, so called from its fancied resemblance to a crow's beak 
(xbpatf a crow), is a thick curved process of bone which arises by a broad base 
from the upper part of the neck 
of the scapula; it is directed at 
first upward and inward; then, 
becoming smaller, it changes its 
direction and passes forward and 
outward. The ascending portion, 
flattened from before backward, 
presents in front a smooth con- 
cave surface, over which passes 
the Subscapularis muscle. The 
horizontal portion is flattened 
from above downward ; its upper 
surface is convex and irregular; 
its under surface is smooth; its 
anterior border is rough, and 
gives attachment to the Pector- 
alis minor; its posterior border 
is also rough, for the coraco- 
acromial ligament, while the 
apex is embraced by the con- 
joined tendon of origin of the 
short head of the Biceps and of 
the Coraco-brachialis. At the 
inner side of the root of the 
coracoid process is a rough im- 
pression for the attachment of 
the conoid ligament, and run- 
ning from it obliquely forward 
and outward on the upper sur- 
face of the horizontal portion an 
elevated ridge for the attachment 
of the trapezoid ligament. [The 
coracoid process can generally be felt in the upper part of the groove, between the 
Pectoralis major and the Deltoid.] 
Structure.-In the head, processes, and all the thickened parts of the bone the 
scapula is cellular in structure-of a dense, compact tissue in the rest of its extent. 
The centre and upper part of the dorsum, but especially the former, are usually so 
thin as to be semi-transparent; occasionally the bone is found wanting in this situ- 
ation and the adjacent muscles come into contact. 
Development (Fig- 203).-By seven centres: one for the body, two for the 
Fig. 203. 
Plan of the Development of the Scapula, by seven centres: the 
epiphyses (except one for the coracoid process) appear at from 
fifteen to seventeen years, and unite between the twenty-second 
and twenty-fifth year. THE HUMERUS. 
237 
coracoid process, two for the acromion,1 one for the posterior border, and one for 
the inferior angle. 
Ossification of the body of the scapula commences about the second month of 
foetal life by the formation of an irregular quadrilateral plate of bone immediately 
behind the glenoid cavity. This plate extends itself so as to form the chief part 
of the bone, the spine growing up from its posterior surface about the third month. 
At birth the chief part of the scapula is osseous, only the coracoid and acromion 
processes, the posterior border, and inferior angle being cartilaginous. About the 
first year after birth ossification takes place in the middle of the coracoid process, 
which usually becomes joined with the rest of the bone at the time when the other 
centres make their appearance. Between the fifteenth and seventeenth years ossifi- 
cation of the remaining centres takes place in quick succession, and in the following 
order: first, near the base of the acromion and in the root of the coracoid process, 
the latter appearing in the form of a broad scale; secondly, in the inferior angle 
and contiguous part of the posterior border; thirdly, near the extremity of the 
acromion; fourthly, in the posterior border. The acromion process, besides being 
formed of two separate nuclei, has its base formed by an extension into it of the 
centre of ossification which belongs to the spine, the extent of which varies in dif- 
ferent cases. The two separate nuclei unite, and then join with the extension car- 
ried in from the spine. These various epiphyses become joined to the bone between 
the ages of twenty-two and twenty-five years. Sometimes failure of union between 
the acromion process and spine occurs, the junction being effected by fibrous tissue 
or by an imperfect articulation ; in some cases of supposed fracture of the acromion 
with ligamentous union it is probable that the detached segment was never united 
to the rest of the bone. 
Articulations.-With the humerus and clavicle. , 
Attachment of Muscles.-To eighteen : to the anterior surface, the Subscapu- 
laris; posterior surface, Supraspinatus, Infraspinatus; spine, Trapezius, Deltoid; 
superior border, Omo-hyoid; vertebral border, Serratus magnus, Levator anguli 
scapulae, Rhomboideus minor and major ; axillary border, Triceps, Teres minor, 
Teres major; glenoid cavity, long head of the Biceps; coracoid process, short head 
of the Biceps, Coraco-brachialis, Pectoralis minor; acromion process, the Platys- 
ma ; and to the inferior angle, occasionally a few fibres of the Latissimus dorsi. 
The Humerus. 
The Humerus is the longest and largest bone of the upper extremity; it pre- 
sents for examination a shaft and two extremities. 
The Upper Extremity is the largest part of the bone; it presents a rounded 
head, joined to the shaft by a constricted portion, called the neck, and two other 
eminences, the greater and lesser tuberosities (Fig. 204). 
The head, nearly hemispherical in form,2 is directed upward, inward, and a 
little backward; its surface is smooth, coated with cartilage in the recent state, 
and articulates with the glenoid cavity of the scapula. The circumference of its 
articular surface is slightly constricted, and is termed the anatomical neck, in con- 
tradistinction to the constriction which exists below the tuberosities. The latter 
is called the surgical neck, from its often being the seat of fracture. [The surgical 
head of the bone, as it should be named, consists of the anatomical head and neck 
1 Anatomists are not agreed as to the number'of centres of ossification for the coracoid and acro- 
mion processes. Humphry describes one only for each process; Cruveilhier gives one for the cora- 
coid and two for the acromion; Thane makes two for the coracoid, and two, sometimes three, for the 
acromion; and Beclard states that in some instances the coracoid has three centres, additional ones 
being formed both for the apex and the base of the process. 
2 Though the head is nearly hemispherical in form, its margin, as Professor Humphry has shown, 
is by no means a true circle. Its greatest measurement is from the top of the bicipital groove in a 
direction downward, inward, and backward. Hence it follows that the greatest elevation of the arm 
can be obtained by rolling the articular surface in this direction-that is to say, obliquely upward, 
outward, and forward. 238 
THE SKELETON. 
and the two tuberosities.] It should be remembered, however, that fracture of the 
anatomical neck does sometimes, though rarely, occur. 
The anatomical neck is obliquely directed, forming an obtuse angle with the 
shaft. It is more distinctly marked in the lower half of its circumference than in 
the upper half, where it presents a narrow groove, separating the head from the 
tuberosities. Its circumference affords attachment to the capsular ligament, and is 
perforated by numerous vascular foramina. 
The greater tuberosity is situated on the outer side of the head and lesser 
tuberosity. Its upper surface is rounded and marked by three flat facets, separated 
by two slight ridges: the anterior facet gives attachment to the tendon of the 
Supraspinatus; the middle one, to the Infraspinatus; the posterior facet and the 
shaft of the bone below it, to the Teres minor. The outer surface of the great 
tuberosity is convex, rough, and continuous with the outer side of the shaft. 
The lesser tuberosity is more prominent, although smaller, than the greater: 
it is situated in front of the head and is directed inward and forward. Its summit 
presents a prominent facet for the insertion of the tendon of the Subscapularis 
muscle. The tuberosities are separated from one another by a deep groove, the 
bicipital groove, so called from its lodging the long tendon of the Biceps muscle, 
with which runs a branch of the anterior circumflex artery. It commences above 
between the two tuberosities, passes obliquely downward and a little inward, and 
terminates at the junction of the upper with the middle third of the bone. It is 
deep and narrow at the commencement, and becomes shallow and a little broader as 
it descends. [Its borders are called, respectively, the anterior and the posterior 
bicipital ridges.] In the recent state it is covered with a thin layer of cartilage, 
lined by a prolongation of the synovial membrane of the shoulder-joint, and receives 
part of the tendons of insertion of the Latissimus dorsi and Pectoralis major mus- 
cles. 
[The two tuberosities and the bicipital groove can be well felt in the living 
model, unless he be very fat or muscular.] 
The shaft of the humerus is almost cylindrical in the upper half of its extent, 
prismatic and flattened below, and presents three borders and three surfaces for 
examination. 
The anterior border runs from the front of the great tuberosity above to the 
coronoid depression below, separating the internal from the external surface. Its 
upper part is very prominent and rough, and forms the outer lip of the bicipital 
groove. It is sometimes called the pectoral ridge, and serves for the attachment of 
the tendon of the Pectoralis major. About its centre it forms the anterior boundary 
of the rough deltoid impression; below, it is smooth and rounded, affording attach- 
ment to the Brachialis anticus. 
The external border runs from the back part of the greater tuberosity to the 
external condyle, and separates the external from the posterior surface. It is 
rounded and indistinctly marked in its upper half, serving for the attachment of 
the external head of the Triceps muscle; its centre is traversed by a broad but 
shallow oblique depression, the musculo-spiral groove ; its lower part is marked by 
a prominent rough margin, a little curved from behind forward [the external con- 
dyloid ridge\, which presents an anterior lip for the attachment of the Supinator 
longus above and Extensor carpi radialis longior below, a posterior lip for the Tri- 
ceps, and an interstice for the attachment of the external intermuscular septum. 
The internal border extends from the lesser tuberosity to the internal condyle. 
Its upper third is marked by a prominent ridge, forming the inner lip of the 
bicipital groove, and gives attachment from above downward to the tendons of the 
Latissimus dorsi, Teres major, and part of the origin of the inner head of the Tri- 
ceps. About its centre is a rough ridge for the attachment of the Coraco-brachia- 
lis, and just below this is seen the entrance of the nutrient canal, directed down- 
ward. Sometimes there is a second canal higher up, which takes a similar direc- 
tion. The inferior third of this border is raised into a slight ridge, which becomes 
very prominent below [the internal condyloid ridge~\ ; it presents an anterior lip THE HUMERUS. 
239 
Fig. 204. 
Surgical Neck 
> SUPINATOR RADII LQNCUS 
EXTENSOR CARPI RADIALIS 
LONCIO R 
Common Origin 
of 
FLEXOR CARPI RADIALIS 
PALMARI8 LONCUS 
FLEXOR PICITORUM SUBLIMIS 
CARPI ULNARIS 
Common Origin 
EXTENSOR.CARP. BAD. SREV 
„ DICITORUM COMMUNIS 
MINIMI DICITI 
„ CARPI ULNARIS 
SUPINATOR BREVIS 
Left Humerus, anterior view. 240 
THE SKELETON. 
Fig. 205. 
for the attachment of the Brachialis anticus, a 
posterior lip for the internal head of the Triceps, 
and an intermediate space for the internal inter- 
muscular septum. 
The external surface is directed outward 
above, where it is smooth, rounded, and covered 
by the Deltoid muscle; forward and outward 
below, where it is slightly concave from above 
downward, and gives origin to part of the Bra- 
chialis anticus muscle. About the middle of 
this surface is seen a rough triangular impres- 
sion for the insertion of the Deltoid muscle, 
and below it the musculo-spiral groove, directed 
obliquely from behind, forward, and downward, 
and transmitting the musculo-spiral nerve and 
superior profunda artery. 
The internal surface, less extensive than 
the external, is directed inward above, forward 
and inward below; at its upper part it is nar- 
row and forms the bicipital groove. The mid- 
dle part of this surface is slightly rough for the 
attachment of the Coraco-brachialis; its lower 
part is smooth, concave, and gives attachment 
to the Brachialis anticus muscle.1 
The posterior surface (Fig. 205) appears 
somewhat twisted, so that its upper part is 
directed a little inward, its lower part back- 
ward and a little outward. Nearly the whole 
of this surface is covered by the external and 
internal heads of the Triceps, the former of 
which is attached to its upper and outer part, 
the latter to its inner and back part, the two 
being separated by the musculo-spiral groove. 
The Lower Extremity is flattened from 
before backward, and curved slightly forward; 
it terminates below in a broad articular sur- 
face which is divided into two parts by a slight 
ridge. Proj ecting on either side are the external 
and internal condyles. The articular surface ex- 
1 A small, hook-shaped process of bone, varying from 
one-tenth to three-quarters of an inch in length, is not 
unfrequently found projecting from the inner surface of 
the shaft of the humerus two inches above the internal 
condyle. It is curved downward, forward, and inward, and 
its pointed extremity is connected to the internal border, 
just above the inner condyle, by a ligament or fibrous 
band, completing an arch through which the median 
nerve and brachial artery pass when these structures 
deviate from their usual course. Sometimes the nerve 
alone is transmitted through it, or the nerve may be 
accompanied by the ulnar interosseous artery in cases 
of high division of the brachial. A well-marked groove 
is usually found behind the process in which the nerve 
and artery are lodged. This space is analogous to the 
supracondyloid foramen in many animals, and probably 
serves in them to protect the nerve and artery from com- 
pression during the contraction of the muscles in this 
region. A detailed account of this process is given by 
Dr. Struthers in his Anatomical. and Physiological Observa- 
tions, p. 202. An accessory portion of the Coraco-bra- 
chialis muscle is frequently connected with this process, 
according to Mr. J. Wood (Journal of Anatomy and Physi- 
ology, No. 1, Nov., 1866, p 47). 
Left Humerus, posterior surface. THE HUMERUS. 
241 
tends a little lower than the condyles, and is curved slightly forward, so as to occupy 
the more anterior part of the bone ; its greatest breadth is in the transverse diameter, 
and it is obliquely directed, so that its inner extremity occupies a lower level than the 
outer. The outer portion of the articular surface presents a smooth rounded eminence 
which has received the name of the capitellum, or radial head of the humerus; it 
articulates with the cup-shaped depression on the head of the radius, and is limited 
to the front and lower part of the bone, not extending as far back as the other por- 
tion of the articular surface. On the inner side of this eminence is a shallow groove 
in which is received the inner margin of the head of the radius. The inner portion 
of the articular surface, the trochlear, presents a deep depression between two well- 
marked borders. This surface is convex from before backward, concave from side 
to side, and occupies the anterior, lower, and posterioi' parts of the bone. The 
external border, less prominent than the internal, corresponds to the interval 
between the radius and the ulna. The internal border is thicker, more prominent, 
and consequently of greater length than the external. The grooved portion of the 
articular surface fits accurately within the greater sigmoid cavity of the ulna; it is 
broader and deeper on the posterior than on the anterior aspect of the bone, and 
is inclined obliquely from behind forward and from without inward. Above the 
back part of the trochlear surface is a deep triangular depression, the olecranon 
fossa, in which is received the summit of the olecranon process in extension of the 
forearm. Above the front part of the trochlear surface is seen a smaller depression, 
the coronoid fossa, which receives the coronoid process of the ulna during flexion 
of the forearm. These fossae are separated from one another by a thin transparent 
lamina of bone, which is sometimes perforated, forming the supratrochlear foramen ; 
their upper margins afford attachment to the anterior and posterior ligaments of the 
elbow-joint, and they are lined in the recent state by the synovial membrane of this 
articulation. Above the front part of the radial tuberosity is seen a slight depres- 
sion which receives the anterior border of the head of the radius when the forearm 
is strongly flexed. The external condyle is a small tubercular eminence, less prom- 
inent than the internal, curved a little forward, and giving attachment to the exter- 
nal lateral ligament of the elbow-joint and to a tendon common to the origin of some 
of the extensor and supinator muscles. The internal condyle, larger and more 
prominent than the external, is directed a little backward: it gives attachment to 
the internal lateral ligament, to the Pronator radii teres, and to a tendon common 
to the origin of some of the flexor muscles of the forearm. The ulnar nerve runs 
in a groove at the back of the internal condyle or between it and the olecranon 
process. These eminences are directly continuous above with tile external and 
internal borders [«. e. the external and internal supracondyloid ridges]. The great 
prominence of the inner one renders it more liable to fracture. 
Structure.-The extremities consist of cancellous tissue covered with a thin 
compact layer; the shaft is composed of a cylinder of compact tissue, thicker at 
the centre than at the extremities, and hollowed out by a large medullary canal, 
which extends along its whole length. 
Development.-By seven centres (Fig. 206): one for the shaft, one for the 
head, one for the tuberosities, one for the radial head, one for the trochlear portion 
of the articular surface, and one for each condyle. The nucleus for the shaft appears 
near the centre of the bone in the eighth week, and soon extends toward the extrem- 
ities. At birth the humerus is ossified nearly in its whole length, the extremities 
remaining cartilaginous. At the beginning of the second year ossification com- 
mences in the head of the bone, and during the third year the Centre for the tube- 
rosities makes its appearance, usually by a single ossific point, but sometimes, 
according to Bdclard, by one for each tuberosity, that for the lesser being small 
and not appearing until after the fourth year. By the fifth year the centres for the 
head and tuberosities have enlarged and become joined, so as to form a single large 
epiphysis. 
The lower end of the humerus is developed in the following manner : At the end 
of the second year ossification commences in the radial portion of the articular sur- 242 
THE SKELETON. 
face, and from this point extends inward, so as to form the chief part of the artic- 
ular end of the bone, the centre for the inner part of the articular surface not 
appearing until about the age of twelve. Os- 
sification commences in the internal condyle 
about the fifth year, and in the external one 
not until about the thirteenth or fourteenth 
year. About the sixteenth or seventeenth 
year the outer condyle and both portions of 
the articulating surface (having already join- 
ed) unite with the shaft; at the eighteenth year 
the inner condyle becomes joined, whilst the 
upper epiphysis, although the first formed, is 
not united until about the twentieth year. 
Articulations.-With the glenoid cavity 
of the scapula and with the ulna and radius. 
Attachment of Muscles.-To twenty- 
five : to the greater tuberosity, the Supraspi- 
natus, Infraspinatus, and Teres minor; to 
the lesser tuberosity, the Subscapularis; to 
the anterior bicipital ridge, the Pectoralis 
major; to the posterior bicipital ridge and 
groove, the Latissimus dorsi and Teres ma- 
jor; to the shaft, the Deltoid, Coraco-bra- 
chialis, Brachialis anticus, external and in- 
ternal heads of the Triceps, Subanconeus; to 
the internal condyle, the Pronator radii teres 
and common tendon of the Flexor carpi ra- 
dialis, Palmaris longus, Flexor digitorum sub- 
limis, and Flexor carpi ulnaris ; to the exter- 
nal condyloid ridge, the Supinator longus and 
Extensoi* carpi radialis longior; to the ex- 
ternal condyle, the common tendon of the 
Extensor carpi radialis brevior, Extensor 
communis digitorum, Extensor minimi digiti, and Extensor carpi ulnaris and Supi- 
nator brevis; to the back of the external condyle, the Anconeus. 
Fig. 206. 
Epiphyses of Head Sc 
Tuberosities blend at 
.5. yr and unite 
with Shafi at 20i!Lf 
Ihiites with 
Shaft at 
Why* 
Plan of the Development of the Humerus, by- 
seven centres. 
The Forearm. 
The Forearm is that portion of the upper extremity which is situated between 
the elbow and wrist. It is composed of two bones, the ulna and the radius. [These 
[Fig. 207. 
Angle at Elbows. 
Angle at Knees.] 
bones are articulated with the humerus, not in a straight line, but at an angle of 
about ten degrees, so that when the hands are turned with the palms forward (supi- THE ULNA. 
243 
nation) the two upper arms are vertical and parallel with each other and with the 
axis of the trunk, but the forearms diverge. This angle at the elbow should 
always be borne in mind in examining for fractures and dislocations and in apply- 
ing splints to the arm and forearm in supination. In pronation the angle dis- 
appears, the hand being swung over to the inside. At the knee a similar angle 
of about ten degrees exists, but there the thighs are convergent and the legs (tibiae) 
are vertical (Fig. 207).1 No joint will better repay careful and minute study in the 
living model, as most of the bony points described below are accessible to touch and 
measurement-a matter cf the utmost importance in injuries at or near this joint.] 
The Ulna. 
The Ulna (Figs. 208, 209), so called from its forming the elbow (cjzA/;), is a 
long bone, prismatic in form, placed at the inner side of the forearm, parallel with 
the radius. It is the larger and longer of the two bones. Its upper extremity, of 
great thickness and strength, forms a large part of the articulation of the elbow- 
joint; it diminishes in size from above downward, its lower extremity being very 
small and excluded from the wrist-joint by the interposition of an interarticular fibro- 
cartilage. It is divisible into a shaft and two extremities. 
The Upper Extremity, the strongest part of the bone, presents for examination 
two large curved processes, the olecranon process and the coronoid process; and two 
concave articular cavities, the greater and lesser sigmoid cavities. 
The Olecranon Process elbow; xpaviov, head) is a large, thick, curved 
eminence situated at the upper and back part of the ulna. It rises somewhat higher 
than the coronoid, and is curved forward at the summit so as to present a prominent 
tip, its base being contracted where it joins the shaft. This is the narrowest part 
of the upper end of the ulna, and consequently the most usual seat of fracture. 
The posterior surface of the olecranon, directed backward, is triangular, smooth, 
subcutaneous, and covered by a bursa. Its upper surface, directed upward, is of a 
quadrilateral form, marked behind by a rough impression for the attachment of the 
Triceps muscle, and in front, near the margin, by a slight transverse groove for the 
attachment of part of the posterior ligament of the elbow-joint. Its anterior sur- 
face is smooth, concave, covered with cartilage in the recent state, and forms the 
upper and back part of the great sigmoid cavity. The lateral borders present a 
continuation of tbe same groove that was seen on the margin of the superior sur- 
face ; they serve for the attachment of ligaments-viz. the back part of the inter- 
nal lateral ligament internally, the posterior ligament externally. To the inner 
border is also attached a part of the Flexor carpi ulnaris, while to the outer border 
is attached the Anconeus. 
The Coronoid Process (xopcowr], anything hooked like a crow's beak [and eZdoc, 
like]) is a rough triangular eminence of bone which projects horizontally forward 
from the upper and front part of the ulna, forming the lower part of the great sig- 
moid cavity. Its base is continuous with the shaft and of considerable strength, so 
much so that fracture of it is an accident of rare occurrence. Its apex is pointed, 
slightly curved upward, and received into the coronoid depression of the humerus 
in flexion of the forearm. Its upper surface is smooth, concave, and forms the 
lower part of the great sigmoid cavity. The under surface is concave, and marked 
internally by a rough impression for the insertion of the Brachialis anticus. At the 
junction of this surface with the shaft is a rough eminence, the tubercle of the ulna, 
for the attachment of the oblique ligament. Its outer surface presents a narrow, 
oblong, articular depression, the lesser sigmoid cavity. The inner surface, by its 
prominent free margin, serves for the attachment of part of the internal lateral 
ligament. At the front part of this surface is a small rounded eminence for the 
attachment of one head of the Flexor digitorum sublimis; behind the eminence, a 
depression for part of the origin of the Flexor profundus digitorum; and, descend- 
1 The angles at the elbow and the knee should be ten degrees, but are exaggerated to emphasize 
them. 244 
THE SKELETON. 
Fig. 208. 
RADIUS 
FLEXOR DICITORUM 
SUBLIMIS 
PRO N ATOR 
RADII. TERES 
occasional 
of FLEXOR LONCUS POLLICIS 
Radial Origin, 
/FLEXOR DICITORUM 
' 6 U B LI M 13 
-SUPINATOR LONCUQ 
Groove fir ext. ossia 
METACARPI POLLICI9 
.Groove ftarlEKT. PRIM) 
INTERNODII POLLICI6 
Styloid Process 
Stylo iol Erocess 
Bones of the Left Forearm, anterior surface. THE ULNA. 
245 
ing from the eminence, a ridge which gives attachment to one head of the Pronator 
radii teres. Occasionally, the Flexor longus pollicis arises from the lower part of 
the coronoid process by a rounded bundle of muscular fibres. 
The Greater Sigmoid Cavity, so called from its resemblance to the old shape 
of the Greek letter 2', is a semilunar depression of large size formed by the olecra- 
non and coronoid processes, and serving for articulation with the trochlear surface 
of the humerus. About the middle of either lateral border of this cavity is a notch 
which coiiuracts it somewhat and serves to indicate the junction of the two processes 
of which it is formed. The cavity is concave from above downward, ancl divided 
into two lateral parts by a smooth elevated ridge which runs from the summit of the 
olecranon to the tip of the coronoid process. Of these two portions, the internal is 
the larger; it is slightly concave transversely, the external portion being convex 
above, slightly concave below. 
The Lesser Sigmoid Cavity is a narrow, oblong, articular depression placed 
on the outer side of the coronoid process and serving for articulation with the head 
of the radius. It is concave from before backward, and its extremities, which are 
prominent, serve for the attachment of the orbicular ligament. 
The shaft is prismatic in form at its upper part, and curved from behind for- 
ward and from within outward, so as to be convex behind and externally; its cen- 
tral part is quite straight, its lower part rounded, smooth, and bent a little outward; 
it tapers gradually from above downward, and presents for examination three bor- 
ders and three surfaces. 
The anterior border commences above at the prominent inner angle of the 
coronoid process, and terminates below in front of the styloid process. It is well 
marked above, smooth and rounded in the middle of its extent, and affords attach- 
ment to the Flexor profundus digitorum: its lower fourth, bounded by an oblique 
ridge, serves for the attachment of the Pronator quadratus. It separates the ante- 
rior from the internal surface. 
The posterior border commences above at the apex of the triangular surface at 
the back part of the olecranon, and terminates below at the back part of the styloid 
process; it is well marked in the upper three-fourths, and gives attachment to an 
aponeurosis common to the Flexor carpi ulnaris, the Extensor carpi ulnaris, and 
the Flexor profundus digitorum muscles; its lower fourth is smooth and rounded.. 
This border separates the internal from the posterior surface. [It is subcutaneous, 
and can be readily felt throughout the entire length of the bone-a point of great 
value in injuries.] 
The external or interosseous border commences above by two lines, which 
converge one from each extremity of the lesser sigmoid cavity, enclosing between 
them a triangular space for the attachment of part of the Supinator brevis, and 
terminates below at the middle of the head of the ulna. Its two middle fourths are 
very prominent, and serve for the attachment of the interosseous membrane; its 
lower fourth is smooth and rounded. This border separates the anterior from the 
posterior surface. 
The anterior surface, much broader above than below, is concave in the upper 
three-fourths of its extent, and affords attachment to the Flexor profundus digito- 
rum ; its lower fourth, also concave, to the Pronator quadratus. The lower fourth 
is separated from the remaining portion of the bone by a prominent ridge directed 
obliquely from above downward and inward; this ridge marks the extent of attach- 
ment of the Pronator above. At the junction of the upper with the middle third 
of the bone is the nutrient canal, directed obliquely upward and inward. 
The posterior surface, directed backward and outward, is broad and concave 
above, somewhat narrower and convex in the middle of its course, narrow, smooth, 
and rounded below. It presents above an oblique ridge which runs from the pos- 
terior extremity of the lesser sigmoid cavity downward to the posterior border; the 
triangular surface above this ridge receives the insertion of the Anconeus muscle, 
whilst the ridge itself affords attachment to the Supinator brevis. The surface of 
bone below this is subdivided by a longitudinal ridge, sometimes called the perpen- 246 
THE SKELETON. 
ULN4 
Fig. 209. 
RADIUS 
-FLEXOR DIQ1TOHUM 
SUBL1MIS 
.Posterior S'orHe,r of Ulna! giving attacfimmt to an aponeurosis common to 
I 
I 
' EXT. CARPI U LN ARI 8 
FLEX. M * 
„ DIGITOR-PROFUND- 
far EXT. CARPI ULNAR. 
for EXT. CARPI RAD. LONG. 
EXT. CARPI RAD.BREVIOR 
EXT. SECUND1 INTERNODI1 POUJC1S, 
fed 
EXT. INDICIS 
EXT. DICITORUM COMMUNIS 
EXT .MINIMI DI Cl T1 
Bones of the Left Forearm, posterior surface. THE ULNA. 
247 
dicular line, into two parts : the internal part is smooth, concave, and gives origin 
to (occasionally is merely covered by) the Extensor carpi ulnaris; the external por- 
tion, wider and rougher, gives attachment from above downward to part of the 
Supinator brevis, the Extensor ossis metacarpi pollicis, the Extensor secundi inter- 
nodii pollicis, and the Extensor indicis muscles. 
The internal surface is broad and concave above, narrow and convex below. 
It gives attachment by its upper three-fourths to the Flexor profundus digitorum 
muscle: its lower fourth is subcutaneous. 
The Lower Extremity of the ulna is of small size and excluded from the artic- 
ulation of the wrist-j oint. It presents for examination two eminences, the outer and 
larger of which is a rounded articular eminence, termed the head of the ulna; the 
inner, narrower and more proj ectiug, is a non-articular eminence, the styloid process. 
The head presents an articular facet, part of which, of an oval form, is directed 
downward and plays on the surface of the triangular fibro-cartilage, which sepa- 
rates it from the wrist-joint; the remaining portion, directed outward, is narrow', 
convex, and received into the sigmoid cavity of the radius. The styloid process 
projects from the inner and back part of the bone, and descends a little lower than 
the head, terminating in a rounded summit which affords attachment to the internal 
lateral ligament of the wrist. The head is separated from the styloid process by a 
depression for the attachment of the triangular interarticular fibro-cartilage, and 
behind by a shallow groove for the passage of the tendon of the Extensor carpi 
ulnaris. [When the hand is supine, the elevation seen at the lower end of the 
ulna is the styloid process; but when the hand is prone, a similar but more globu- 
lar elevation in the same place is the head of the ulna, the styloid process being 
then antero-external. This change of relation can be well studied in the living 
model, as well as seen in an articulated skeleton.] 
Structure.-Similar to that of the other long bones. 
Development.-By three centres: one for the shaft, one for the inferior extrem- 
ity, and one for the olecranon (Fig. 210). Ossification commences near the middle 
of the shaft about the eighth week, and 
soon extends through the greater part of 
the bone. At birth the ends are cartilagi- 
nous. About the fourth year a separate 
osseous nucleus appears in the middle of 
the head, which soon extends into the sty- 
loid process. About the tenth year ossific 
matter appears in the olecranon near its 
extremity, the chief part of this process 
being formed from an extension of the 
shaft of the bone into it. At about the 
sixteenth year the upper epiphysis becomes 
joined, and at about the twentieth year the 
lower one. 
Articulations.-With the humerus and 
radius. 
Attachment of Muscles.-To sixteen: 
to the olecranon, the Triceps, Anconeus, 
and one head of the Flexor carpi ulnaris; 
to the coronoid process, the Brachialis anti- 
cus, Pronator radii teres, Flexor sublimis 
digitorum, and Flexor profundus digito- 
rum, occasionally also the Flexor longus 
pollicis; to the shaft, the Flexor profundus 
digitorum, Pronator quadratus, Flexor carpi 
ulnaris, Extensor carpi ulnaris, Anconeus, 
Supinator brevis, Extensor ossis metacarpi 
pollicis, Extensoi' secundi internodii pollicis, and Extensor indicis. 
Fig. 210. 
Appears atWOryZ 
OLeeranan 
-Joins Skqft. at i'J" 
Xppsars at 4 
■Joins Shafi at 2Ofy u.* 
Plan of the Development of the Ulna, by three 
centres. 248 
THE SKELETON. 
The Radius. 
The Radius (radius, a ray, or spoke of a wheel) is situated on the outer side of 
the forearm, lying parallel with the ulna, which exceeds it in length and size. [It 
lies nearly parallel with the ulna in the anatomical position-i. e. the thumb turned 
out. When the hand is pronated-z. e. thumb in-the radius crosses the ulna, forjn- 
mg a very long X.] Its upper end is small, and forms only a small part of the 
elbow-joint, but its lower end is large, and forms the chief part of the wrist. It is 
one of the long bones, prismatic in form, slightly curved longitudinally, and, like 
other long bones, has a shaft and two extremities. 
The Upper Extremity presents a head, neck, and tuberosity. The head is of 
a cylindrical form, depressed on its upper surface into a shallow cup which articu- 
lates with the capitellum or radial head of the humerus. Around the circumference 
of the head is a smooth articular surface coated with cartilage in the recent state, 
broad internally where it rotates within the lesser sigmoid cavity of the ulna, narrow 
in the rest of its circumference to play in the orbicular ligament. The head is sup- 
ported on a round, smooth, and constricted portion of bone called the neck, which 
presents, behind, a slight ridge for the attachment of part of the Supinator brevis. 
Beneath the neck, at the inner and front aspect of the bone, is a rough eminence, 
the bicipital tuberosity. Its surface is divided into two parts by a vertical line-a 
posterior rough portion for the insertion of the tendon of the Biceps muscle; and 
%n anterior smooth portion, on which a bursa is interposed between the tendon and 
the bqne. [The head of the bone is always marked by a dimple, where it can be 
readily felt, and its rotation or non-rotation with the lower end be determined-a 
matter of importance in injuries. This dimple is very marked in extension, but 
disappears by the time semiflexion is reached.] 
The shaft of the bone is prismoid in form, narrower above than below, and 
slightly curved, so as to be convex outward. It presents three surfaces, separated 
by three borders. 
The anterior border extends from the lower part of the tuberosity above to the 
anterior part of the base of the styloid process below. It separates the anterior 
from the external surface. Its upper third is very prominent, and from its oblique 
direction, downward and outward, has received the name of the oblique line of the 
radius. It gives attachment externally to the Supinator brevis; internally to the 
Flexor longus pollicis ; and between these to the Flexor digitorum sublimis. The 
middle third of the anterior border is indistinct and rounded. Its lower fourth is 
sharp, prominent, affords attachment to the Pronator quadratus, and terminates in a 
small tubercle, into which is inserted the tendon of the Supinator longus. 
The posterior border commences above, at the back part of the neck of the 
radius, and terminates below, at the posterior part of the base of the styloid pro- 
cess ; it separates the posterior from the external surface. It is indistinct above and 
below, but well marked in the middle third of the bone. 
The internal or interosseous border commences above, at the back part of the 
tuberosity, where it is rounded and indistinct, becomes sharp and prominent as it 
descends, and at its lower part divides into two ridges, which descend to the anterior 
and posterior margins of the sigmoid cavity. This border separates the anterior 
from the posterior surface, and has the interosseous membrane attached to it 
throughout the greater part of its extent. 
The anterior surface is narrow and concave for its upper two-thirds, and gives 
attachment to the Flexor longus pollicis muscle; below, it is broad and flat and 
gives attachment to the Pronator quadratus. At the junction of the upper and 
middle thirds of this surface is the nutrient foramen, which is directed obliquely 
upward. 
The posterior surface is rounded, convex, and smooth in the upper third of its 
extent, and covered by the Supinator brevis muscle. Its middle third is broad, 
slightly concave, and gives attachment to the Extensor ossis metacarpi pollicis 
above, the Extensor primi internodii pollicis below. Its lower third is broad, THE RADIUS. 
249 
convex, and covered by the tendons of the muscles, which subsequently run in 
the grooves on the lower end of the bone. 
The external surface is rounded and convex throughout its entire extent. Its 
upper third gives attachment to the Supinator brevis muscle. About its centre is 
seen a rough ridge for the insertion of the Pronator radii teres muscle. Its lower 
part is narrow, and covered by the tendons of the Extensor ossis metacarpi pollicis 
and Extensor primi internodii nollicis muscles. 
The Lower Extremity of the radius is large, of quadrilateral form, and pro- 
vided with two articular surfaces-one at the extremity for articulation with the 
carpus, and one at the inner side of the bone for articulation with the ulna. The 
carpal articular surface is of triangular form, concave, smooth, and divided by a 
slight antero-posterior ridge into two parts. Of these, the external is large, of a 
triangular form, and articulates with the scaphoid bone; the inner, smaller and 
quadrilateral, articulates with the semilunar. The articular surface for the ulna is 
called the sigmoid cavity of the radius; it is narrow, concave, smooth, and articu- 
lates with the head of tbe ulna. The circumference of this end of the bone pre- 
sents three surfaces-an anterior, external, and posterior. The anterior surface, 
rough and irregular, affords attachment to the anterior ligament of the wrist-joint. 
The external surface is prolonged obliquely downward into a strong conical pro- 
jection, the styloid process, which gives attachment by its base to the tendon of the 
Supinator longus, and by its apex to the external lateral ligament of the wrist-joint. 
The outer surface of this process is marked by two grooves, which run obliquely 
downward and forward, and are separated from one another by an elevated ridge. 
The anterior one gives passage to the tendon of the Extensor ossis metacarpi pol- 
licis, the posterior one to the tendon of the Extensor primi internodii pollicis. The 
posterior surface is convex, affords attachment to the posterior ligament of the wrist, 
and is marked by three grooves. Proceeding from without inward, the first groove 
is broad, but shallow, and subdivided into 
two by a slightly elevated ridge: the outer 
of these two transmits the tendon of the 
Extensor carpi radialis longior, the inner 
the tendon of the Extensor carpi radialis 
brevior. The second, which is near the 
centre of the bone, is a deep but narrow 
groove directed obliquely from above, 
downward and outward ; it transmits the 
tendon of the Extensor secundi internodii 
pollicis. The third, lying most inter- 
nally, is a broad groove for the passage 
of the tendons of the Extensor indicis, 
Extensor communis digitorum, and Ex- 
tensor minimi digiti, the tendon of the 
last-named muscle passing through the 
groove at the point of articulation of the 
radius with the ulna and lying in a sepa- 
rate sheath of the annular ligament. 
Structure.-Similar to that of the 
other long bones. 
Development (Fig. 211).-By three 
centres: one for the shaft, and one for 
each extremity. That for the shaft 
makes its appearance near the centre 
of the bone, soon after the development 
of the humerus commences. At birth 
the shaft is ossified, but the ends of the bone are cartilaginous. About the end of 
the second year ossification commences in the lower epiphysis, and about the fifth 
year in the upper one. At the age of seventeen or eighteen the upper epiphysis 
Fig. 211. 
Appears at 5 th y- 
■Vwtep with Shaft aba at 
■pubw+p 
Appears at Z'.'f yH- 
'Unites with. Shaft a 
20A y'T 
Plan of the Development of the Radius, by three 
centres. 250 
THE SKELETON. 
becomes joined to the shaft, the lower epiphysis becoming united about the twentieth 
year. 
Articulations.-With four bones: the humerus, ulna, scaphoid, and semilunar 
Attachment of Muscles.-To nine: to the tuberosity, the Biceps; to the 
oblique ridge, the Supinator brevis, Flexor sublimis digitorum, and Flexor longus 
pollicis; to the shaft (its anterior surface), the Flexor longus pollicis and Pronator 
quadratus ; (its posterior surface), the Extensor ossis metacarpi pollicis and Extensor 
primi internodii pollicis; (its outer surface), the Pronator radii teres; and to the 
styloid process, the Supinator longus. 
The skeleton of the Hand is subdivided into three segments-the Carpus or 
wrist-bones, the Metacarpus or bones of the palm, and the Phalanges or bones of 
the fingers. [The anatomical position of the hand is with the thumbs out and 
palms forward.] 
THE HAND. 
The Carpus. 
The bones of the Carpus the wrist), eight in number, are arranged in 
two rows. Those of the upper row, enumerated from the radial to the ulnar side, 
are the scaphoid, semilunar, cuneiform, and pisiform; those of the lower row, 
enumerated in the same order, are the trapezium, trapezoid, os magnum, and 
unciform. 
Common Characters of the Carpal Bones. 
Each bone (excepting the pisiform) presents six surfaces. Of these, the ante- 
rior or palmar and the posterior or dorsal are rough for ligamentous attachment, 
the dorsal surface being generally the broader of the two. The superior [or proxi- 
mal\ and inferior [or distaT] are articular, the superior generally convex, the infe- 
rior concave; and the internal and external are also articular when in contact with 
contiguous bones, otherwise rough and tubercular. Their structure in all is similar, 
consisting of cancellous tissue enclosed in a layer of compact bone. Each bone is 
also developed from a single centre of ossification. 
Bones of the Upper Row (Figs. 212, 213). 
The Scaphoid (axdiprp a boat, and eZdoc, like) is the largest bone of the first 
row. It has received its name from its fancied resemblance to a boat, being broad 
at one end and narrowed like a prow at the opposite. It is situated at the upper 
and outer part of the carpus, its direction being from above downward, outward, 
and forward. The superior surface is convex, smooth, of triangular shape, and 
articulates with the lower end of the radius. The inferior surface, directed down- 
ward, outward, and backward, is smooth, convex, also triangular, and divided by a 
slight ridge into two parts, the external of which articulates with the trapezium, 
the inner with the trapezoid. The posterior or dorsal surface presents a narrow, 
rough groove which runs the entire breadth of the bone and serves for the attach- 
ment of ligaments. The anterior or palmar surface is concave above, and elevated 
at its lower and outer part into a prominent rounded tubercle, which projects for- 
ward from the front of the carpus and gives attachment to the anterior annular 
ligament of the wrist. The external surface is rough and narrow, and gives attach- 
ment to the external lateral ligament of the wrist. The internal surface presents 
two articular facets; of these, the superior or smaller one is flattened, of semilunar 
form, and articulates with the semilunar; the inferior or larger is concave, forming 
with the semilunar bone a concavity for the head of the os magnum. 
To ascertain to which side the bone belongs, hold it with the superior or radial 
convex articular surface upward, and the posterior surface-i. e. the narrow non- BONES OF THE UPPER ROW. 
251 
Fig. 212. 
Carp as 
ir'fr 
t0^C/ofi 
E*T RAD|ALIS 
ALIS l0 < 
Metuca/rpiia 
EXT' "RlM.y 
'nti-'RNooh 
■>T- SECUM01 
Phalanges 
Row 
*r-'^c(s 
rexT. digit. 
COMMON. < 
E*r- Digit, 
cOMMU(\i, 
Bones of the Left Hand, dorsal surface. 
articular grooved surface-toward you. The tubercle on the outer surface points to 
the side to which the bone belongs.1 
1 In these directions each bone is supposed to be placed in its natural position; that is, such a 
position as it would occupy when the arm is hanging by the side, the forearm in a position of supi- 
nation, the thumb being directed outward and the palm of the hand looking forward. 252 
THE SKELETON. 
Articulations.-With five bonesthe radius above, trapezium and trapezoid 
below, os magnum and semilunar internally. 
The Semilunar {semi, half; luna, moon) bone may be distinguished by its deep 
concavity and crescentic outline. It is situated in the centre of the upper row of 
the carpus, between the scaphoid and cuneiform. The superior surface, convex, 
smooth, and bounded by four edges, articulates with the radius. The inferior sur- 
face is deeply concave, and of greatei1 extent from before backward than trans- 
versely ; it articulates with the head of the os magnum, and by a long narrow facet 
(separated by a ridge from the general surface) with the unciform bone. The ante- 
rior or palmar and posterior or dorsal surfaces are rough, for the attachment of 
ligaments, the former being the broader and of somewhat rounded form. The 
external surface presents a narrow, flattened, semilunar facet for articulation with 
the scaphoid. The internal surface is marked by a smooth, quadrilateral facet, for 
articulation with the cuneiform. 
Hold it with the convex articular surface for the radius upward and the narrow- 
est non-articular surface toward you. The semilunar facet for the scaphoid will be 
on the side to which the bone belongs. 
Articulations.-With five bones: the radius above, os magnum and unciform 
below, scaphoid and cuneiform on either side. 
The Cuneiform {cuneus, a wedge, and/orma, likeness) may be distinguished by 
its pyramidal shape (V Os Pyramidal), and by its having an oval, isolated facet for 
articulation with the pisiform bone. It is situated at the upper and inner side of 
the carpus. The superior surface presents an internal, rough, non-articular por- 
tion, and an external or articular portion, which is convex, smooth, and articulates 
with the interarticular fibro-cartilage of the wrist. The inferior surface, directed 
outward, is concave, sinuously curved, and smooth, for articulation with the unci- 
form. The posterior or dorsal surface is rough, for the attachment of ligaments. 
The anterior or palmar surface presents at its inner side an oval facet, for articula-. 
tion with the pisiform, and is rough externally, for ligamentous attachment. The 
external surface, the base of the pyramid, is marked by a flat, quadrilateral, smooth 
facet, for articulation with the semilunar. The internal surface, the summit of the 
pyramid, is pointed and roughened, for the attachment of the internal lateral liga- 
ment of the wrist. 
Hold the bone with the surface supporting the pisiform facet away from you, and 
the concavo-convex surface for the unciform downward. The base of the wedge (z. e. 
the broad end of the bone) will be on the side to which it belongs. 
Articulations.-With three bones: the semilunar externally, the pisiform in 
front, the unciform below; and with the triangular interarticular fibro-cartilage, 
which separates it from the lower end of the ulna. 
The Pisiform {pisum, a pea; forma, likeness) may be known by its small size 
and by its presenting a single articular facet. It is situated at the anterior and 
inner side of the carpus, is nearly spherical inform, and presents on its posterior sur- 
face a smooth oval facet, for articulation with the cuneiform. This facet approaches 
the superior, but not the inferior, border of the bone. The anterior or palmar surface 
is rounded and rough, and gives attachment to the anterior annular ligament. The outer 
and inner surfaces are also rough, the former being convex, the latter usually concave. 
Hold the bone with the posterior surface, that which presents the articular facet, 
toward you, in such a manner that the faceted portion of the surface is uppermost. 
The outer, convex surface will point to the side to which it belongs. 
Articulations.-With one bone, the cuneiform. 
Attachment of Muscles.-To two: the Flexor carpi ulnaris and Abductor 
minimi digiti, and to the anterior annular ligament. 
Bones of the Lower Row (Figs. 212, 213) 
The Trapezium a table) is of very irregular form. It may be distin- 
guished by a deep groove, for the tendon of the Flexor carpi radialis muscle. It is BONES OF THE LOWER ROW. 
253 
situated at the external and inferior part of the carpus, between the scaphoid and 
first metacarpal bone. The superior surface, concave and smooth, is directed upward 
and inward, and articulates with the scaphoid. The inferior surface, directed down- 
Fig. 213, 
Jo7l 
O6&'6, ■ (O'6 
Ca/r]uvs 
FLEXOR., CARPI ULNARIS 
s^eN'°''Po°u='s 
FLEXOR BREVIS MINIMI DICITI 
FLEXOR OSSIS METACARPi- 
MININII DtCITl 
Metacar/uLs 
Sesamoid 
ioMS' 
FLEX. BREVIS' 
& 
abductor 
(MINIMI DICITI 
adductor' 
P0L.LICI5. 
ABDUCTOR 
""POLLICIS 
FLEXOR » to 
SRE.VLS POLLICIS\ 
LONGUs" 
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profunou9 
ward and outward, is oval, concave from side to side, convex from before backward, 
so as to form a saddle-shaped surface, for articulation with the base of the first meta- 
carpal bone. The anterior or palmar surface is narrow and rough. At its upper 
Bones of the Left Hand, palmar surface. 254 
THE SKELETON. 
part is a deep groove running from above obliquely downward and inward ; it trans- 
mits the tendon of the Flexor carpi radialis, and is bounded externally by a promi- 
nent ridge, the oblique ridge of the trapezium. This surface gives attachment to 
the Abductor pollicis, Flexor ossis metacarpi pollicis, and Flexor brevis pollicis 
muscles and the anterior annular ligament. The posterior or dorsal surface is rough, 
and the external surface also broad and rough, for the attachment of ligaments. 
The internal surface presents two articular facets: the upper one, large and con- 
cave, articulates with the trapezoid; the lower one, narrow and flattened, with the 
base of the second metacarpal bone. 
Hold the bone with the saddle-shaped surface downward and the grooved surface 
away from you. The prominent, rough, non-articular surface points to the side to 
which the bone belongs. 
Articulations.-With four bones : the scaphoid above, the trapezoid and second 
metacarpal bones internally, the first metacarpal below. 
Attachment of Muscles.-Abductor pollicis, Flexor ossis metacarpi pollicis, 
and part of the Flexor brevis pollicis. 
The Trapezoid is the smallest bone in the second row. It may be known by its 
wedge-shaped form, the broad end of the wedge forming the dorsal, the narrow end 
the palmar surface, and by its having four articular surfaces touching each other 
and separated by sharp edges. The superior surface, quadrilateral in form, smooth 
and slightly concave, articulates with the scaphoid. The inferior surface articulates 
with the upper end of the second metacarpal bone; it is convex from side to side, 
concave from before backward, and subdivided by an elevated ridge into two unequal 
lateral facets. The posterior or dorsal and anterior or palmar surfaces are rough, for 
the attachment of ligaments, the former being the larger of the two. The external 
surface, convex and smooth, articulates with the trapezium. The internal surface 
is concave and smooth in front, for articulation with the os magnum ; rough behind, 
for the attachment of an interosseous ligament. 
Hold the bone with the larger non-articular surface toward you and the smooth, 
quadrilateral articular surface upward. The convex articular surface will point to 
the side to which the bone belongs.1 
Articulations.-With four bones: the scaphoid above, second metacarpal bone 
below, trapezium externally, os magnum internally. 
Attachment of Muscles.-Part of the Flexor brevis pollicis. 
The Os Magnum is the largest bone of the carpus, and occupies the centre of 
the wrist. It presents above a rounded portion or head, which is received into the 
concavity formed by the scaphoid and semilunar bones; a constricted portion or 
neck ; and below, the body. The superior surface is rounded, smooth, and articu- 
lates with the semilunar. The inferior surface is divided by two ridges into three 
facets, for articulation with the second, third, and fourth metacarpal bones, that for 
the third (the middle facet) being the largest of the three. The posterior or dorsal 
surface is broad and rough; the anterior or palmar, narrow, rounded, and also 
rough, for the attachment of ligaments. The external surface articulates with the 
trapezoid by a small facet at its anterior inferior angle, behind which is a rough 
depression for the attachment of an interosseous ligament. Above this is a deep 
and rough groove which forms part of the neck and serves for the attachment of liga- 
ments, bounded superiorly by a smooth convex surface, for articulation with the 
scaphoid. The internal surface articulates with the unciform by a smooth, con- 
cave, oblong facet which occupies its posterior and superior parts, and is rough in 
front, for the attachment of an interosseous ligament. 
Hold the bone with the broader, non-articular surface toward you and the head 
upward. The small articular facet at the anterior inferior angle of the external 
surface will point to the side to which the bone belongs. 
1 Occasionally in a badly-marked bone there is some difficulty in ascertaining to which side the 
bone belongs; the following method will sometimes be found useful: Hold the bone with its broader, 
non-articular surface upward, so that its sloping border is directed toward you. The border will 
slope to the side to which the bone belongs. THE METACARPUS. 
255 
Articulations.-With seven bones: the scaphoid and semilunar above; the 
second, third, and fourth metacarpal below; the trapezoid on the radial side; and 
the unciform on the ulnar side. 
Attachment of Muscles.-Part of the Flexor brevis pollicis. 
The Unciform (uncus, a hook ; forma, likeness) may be readily distinguished 
by its wedge-shaped form and the hook-like process that projects from its palmar 
surface. It is situated at the inner and lower angle of the carpus, with its base 
downward, resting on the two inner metacarpal bones and its apex directed upward 
and outward. The superior surface, the apex of the wedge, is narrow, convex, 
smooth, and articulates with the semilunar. The inferior surface articulates with 
the fourth and fifth metacarpal bones, the concave surface for each being separated 
by a ridge which runs from before backward. The posterior or dorsal surface is 
triangular and rough, for ligamentous attachment. The anterior or palmar sur- 
face presents, at its lower and inner side, a curved hook-like process of bone, the 
unciform process, directed from the palmar surface forward and outward. It gives 
attachment by its apex to the annular ligament, by its inner surface to the Flexor 
brevis minimi digiti and the Flexor ossis metacarpi minimi digiti; and is grooved 
on its outer side for the passage of the Flexor tendons into the palm of the hand. 
This is one of the four eminences on the front of the carpus to which the anterior 
annular ligament is attached, the others being the pisiform internally, the oblique 
ridge of the trapezium, and the tuberosity of the scaphoid externally. The internal 
surface articulates with the cuneiform by an oblong facet cut obliquely from above, 
downward and inward. The external surface articulates with the os magnum by 
its upper and posterior part, the remaining portion being rough, for the attachment 
of ligaments. 
Hold the bone with the hooked process away from you, and the articular surface, 
divided into two parts for the metacarpal bones, downward. The concavity of the 
process will be on the side to which the bone belongs. 
[In lean persons the scaphoid, trapezium, pisiform, and unciform, and sometimes 
the cuneiform, can be.felt. The pisiform is always easily made out.] 
Articulations.-With five bones: the semilunar above, the fourth and fifth 
metacarpal below, the cuneiform internally, the os magnum externally. 
Attachment of Muscles.-To two: the Flexor brevis minimi digiti and 
Flexor ossis metacarpi minimi digiti, and to the anterior annular ligament. 
The Metacarpus. 
The Metacarpal Bones are five in number: they are long cylindrical bones, 
presenting for examination a shaft and two extremities. 
Common Characters of the Metacarpal Bones. 
The shaft is prismoid in form and curved longitudinally, so as to be convex in 
the longitudinal direction behind, concave in front. It presents three surfaces, two 
lateral and one posterior. The lateral surfaces are concave, for the attachment of 
the Interossei muscles, and separated from one another by a prominent line. The 
posterior or dorsal surface is triangular, smooth, and flattened below, and covered, 
in the recent state, by the tendons of the Extensor muscles. In its upper half it 
is divided by a ridge into two narrow lateral depressions, for the attachment of the 
Dorsal interossei muscles.1 This ridge bifurcates a little above the centre of the 
bone, and its branches run to the small tubercles on each side of the digital 
extremity. 
The carpal extremity, or base, is of a cuboidal form, and broader behind than 
in front: it articulates above with the carpus, and on each side with the adjoining 
1 By these ridges the metacarpal bones of the hand may be at once differentiated from those of 
the foot. 256 
THE SKELETON. 
metacarpal bones; its dorsal and palmar surfaces are rough, for the attachment of 
tendons and ligaments. 
The digital extremity, or head, presents an oblong surface, flattened at each 
side, for articulation with the first phalanx ; it is broader and extends farther for- 
ward in front than behind, and is longer in the antero-posterior than in the trans- 
verse diameter. On either side of the head is a deep depression, behind which is 
the tubercle, for the attachment of the lateral ligament of the metacarpo-phalangeal 
joint. The posterior surface, broad and flat, supports the Extensor tendons; the 
anterior surface presents a median groove bounded on each side by a tubercle, for 
the passage of the Flexor tendons. 
Peculiar Characters of the Metacarpal Bones 
The metacarpal bone of the thumb is shorter and wider than the rest, 
diverges to a greater degree from the carpus, and its palmar surface is directed 
inward toward the palm. The shaft is flattened and broad on its dorsal aspect, 
and does not present the bifurcated ridge which is found on the other metacarpal 
bones; it is concave from before backward on its palmar surface. The carpal 
extremity, or base, presents a concavo-convex surface, for articulation with the tra- 
pezium, and has no lateral facets. The digital extremity is less convex than that 
of the other metacarpal bones, broader from side to side than from before back- 
ward, and terminates anteriorly in a small articular eminence on each side, over 
which play two sesamoid bones. 
The side to which this bone belongs may be known by observing the little 
prominence which is marked on the outer or radial side of its posterior surface just 
above the base, for the tendon of the Extensor ossis metacarpi pollicis. If the 
bone is held with the palmar surface upward and the base toward the student, the 
prominence will point to the side to which the bone belongs. Another means by 
which the side to which the bone belongs may be ascertained is by holding it in the 
position it occupies in the hand, with the carpal extremity upward and the dorsal 
surface backward; the narrower, radial border will point to the side to which it 
belongs. 
The metacarpal bone of the index finger is the longest and its base the largest 
of the other four. Its carpal extremity is prolonged upward and inward. The dorsal 
and palmar surfaces of this extremity are rough, for the attachment of tendons and 
ligaments. It presents four articular facets: the first, at the end of the bone, is 
concave from side to side, convex from before backward, and articulates with the 
trapezoid; the second, on the radial side, is a flat quadrilateral facet, for the trape- 
zium ; the third and fourth are on the ulnar side of the extremity, and are sepa- 
rated by a ridge; the proximal one, long and narrow, articulates with the os mag- 
num ; the distal one, considerably broader and notched, with the third metacarpal 
bone. 
The side to which this bone belongs is marked by the absence of the lateral 
facet on the outer (radial) side of its head, so that if the bone be placed with its 
base toward the student and the palmar surface upward, the side on which there is 
no lateral facet will be that to which it belongs. If the head of the bone be indis- 
tinctly marked, the base can be recognized, its ulnar or inner surface being marked 
by the two long narrow facets for the os magnum and third metacarpal, easily dis- 
tinguishable from the single quadrangular facet on the radial side for the trape- 
zium, which will then mark the side to which the bone belongs. 
The metacarpal bone of the middle finger is a little smaller than the preced- 
ing ; it presents a pyramidal eminence (the styloid process) on the radial side of its 
base (dorsal aspect), which extends upward behind the os magnum. [This can 
always be felt, and is a valuable landmark.] The carpal articular facet is concave 
behind, flat and horizontal in front, and corresponds to the os magnum. On the 
radial side is a smooth concave facet, for articulation with the second metacarpal bone; 
and on the ulnar side two small oval facets, for articulation with the fourth metacarpal. PHALANGES. 
257 
The side to which this bone belongs is easily recognized by the projecting angle 
on the lower radial corner of its base. With the palmar surface uppermost and 
the base toward the student, this projection points toward the side to which the 
bone belongs. 
The metacarpal bone of the ring1 finger is shorter and smaller than the pre- 
ceding, and its base small and quadrilateral, the carpal surface of the base present- 
ing two facets, for articulation with the unciform and os magnum. On the radial 
side are two oval facets, for articulation with the third metacarpal bone; and on 
the ulnar .side a single concave facet, for the fifth metacarpal. 
If this bone is placed with the base toward the student and the palmar surface 
upward, the radial side of the base, which has two facets for articulation with the 
third metacarpal bone, will be on the side to which it belongs. If, as sometimes 
happens in badly-marked bones, one of these facets is indistinguishable, the side 
may be known by the greatly larger size in such cases of the facet for the fifth 
metacarpal bone, which is therefore situated on the side to which the bone does 
not belong. 
The metacarpal bone of the little finger may be distinguished by the concavo- 
convex form of its carpal surface, which articulates with the unciform, and by its 
having only one lateral articular facet, which corresponds with the fourth meta- 
carpal bone. On its ulnar side is a prominent tubercle, for the insertion of the 
tendon of the Extensor carpi ulnaris. The dorsal surface of the shaft is marked 
by an oblique ridge which extends from near the ulnar side of the upper extremity 
to the radial side of the lower. The outer division of this surface serves for the 
attachment of the fourth Dorsal interosseous muscle; the inner division is smooth, 
and covered by the Extensor tendons of the little finger. 
If this bone is placed with its base toward the student and its palmar surface 
upward, the side of the head which has a lateral facet will be that to which the 
bone belongs. 
Articulations.-Besides the phalangeal articulations, the first metacarpal bone 
articulates with the trapezium; the second, with the trapezium, trapezoid, os mag- 
num, and third metacarpal bones; the third, with the os magnum and second 
and fourth metacarpal bones; the fourth, with the os magnum, unciform, and 
third and fifth metacarpal bones; and the fifth, with the unciform and fourth 
metacarpal. 
The first has therefore no lateral facets on its carpal extremity; the second has 
one on its radial and one on its ulnar side, divided by a ridge into two parts; the 
third has one on its radial and two on its ulnar side; the fourth has two on its radial 
and one on its ulnar side; and the fifth has only one on its radial side. 
Attachment of Muscles.-To the metacarpal bone of the thumb, three: the 
Flexor ossis metacarpi pollicis, Extensor ossis metacarpi pollicis, and first Dorsal 
interosseous ; to the second metacarpal bone, five : the Flexor carpi radialis, Exten- 
sor carpi radialis longior, first and second Dorsal interosseous, and first Palmar 
• interosseous;1 to the third, five: the Extensor carpi radialis brevior, Flexor brevis 
pollicis, Adductor pollicis, and second and third Dorsal interosseous; to the fourth, 
three: the third and fourth Dorsal and second Palmar interosseous; to the fifth, 
five: the Extensor carpi ulnaris, Flexor carpi ulnaris, Flexor ossis metacarpi min- 
imi digiti, fourth Dorsal, and third Palmar interosseous. 
Phalanges. 
The Phalanges (internodia) are the bones of the fingers; they are fourteen in 
number, three for each finger and two for the thumb. They are long bones, and 
present for examination a shaft and two extremities. The shaft tapers from above 
downward, is convex posteriorly, concave in front from above downward, flat from 
side to side, and marked laterally by rough ridges which give attachment to the 
fibrous sheaths of the Flexor tendons. The metacarpal [proximal] extremity or 
1 The Flexor brevis pollicis is also frequently attached to this bone. 258 
THE SKELETON. 
base, in the first row, presents an oval concave articular surface, broader from side 
to side than from before backward; and the same extremity in the other two rows, 
a double concavity separated by a longitudinal median ridge extending from before 
backward. The digital [distal] extremities are smaller than the others, and ter- 
minate, in the first and second row, in two small lateral condyles separated by a 
slight groove, the articular surface being prolonged farther forward on the palmar 
than on the dorsal surface, especially in the first row. 
The Ungual Phalanges are convex on their dorsal, flat on their palmar sur- 
faces ; they are recognized by their small size and by a roughened elevated surface 
of a horseshoe form on the palmar aspect of their ungual extremity, which serves to 
support the sensitive pulp of the finger. 
[The first, second, and third phalanges are sometimes called, after the French, 
the phalanx, phalangine, and phalangette, the phalangette being the terminal 
phalanx.] 
Articulations.-The first row with the metacarpal bones and the second row 
of phalanges; the second row with the first and third; the third, with the second 
row. 
Attachment of Muscles.-To the base of the first phalanx of the thumb, four 
muscles: the Extensor primi internodii pollicis, Flexor brevis pollicis, Abductor 
Fig. 214. 
Carpus 
1. centrefor each bone 
All cartilaginous at birth 
Metacarpus 
2 Centres for each lone 
1 for Shaft 
if or Digital Extremity 
except 
Phalanges 
2 Centres for each lone 
I for Shaft 
1far Metacarpal Ext*. 
l unite 
-appears yZ- 
"77* • 
8 
"ajijieoLrs ijr- 
unite 1820'tyZ. 
upy-* 
8 wk- 
I 'unite 18-2r0*by%- 
Plan of the Development of the Hand. 
pollicis, Adductor pollicis; to the second phalanx, two: the Flexor longus pollicis 
and the Extensor secundi internodii; to the base of the first phalanx of the index 
finger, the first Dorsal and the first Palmar interosseous; to that of the middle 
finger, the second and third Dorsal interosseous; to that of the ring-finger, the THE LOWER EXTREMITY. 
259 
fourth Dorsal and the second Palmar interosseous; and to that of the little finger, 
the third Palmar interosseous, the Flexor brevis minimi digiti, and Abductor minimi 
digiti; to the second phalanges, the Flexor sublimis digitorum, Extensor communis 
digitorum, and, in addition, the Extensor indicis to the index finger, the Extensor 
minimi digiti to the little finger; to the third phalanges, the Flexor profundus dig- 
itorum and Extensor communis digitorum. 
Development of the Bones of the Hand. 
The Carpal Bones are each developed by a single centre. At birth they are 
all cartilaginous. Ossification proceeds in the following order (Fig. 214): In the 
os magnum and unciform an ossific point appears during the first year, the former 
preceding the latter; in the cuneiform, at the third year; in the trapezium and 
semilunar, at the fifth year, the former preceding the latter; in the scaphoid, at the 
sixth year; in the trapezoid, during the eighth year; and in the pisiform, about the 
twelfth year. 
The Metacarpal Bones are each developed by two centres: one for the shaft, 
and one for the digital extremity, for the four inner metacarpal bones; one for the 
shaft, and one for the base, for the metacarpal bone of the thumb, which in this 
respect resembles the phalanges.1 Ossification commences in the .centre of the shaft 
about the eighth or ninth week, and gradually proceeds to either end of the bone; 
about the third year the digital extremities of the four inner metacarpal bones and 
the base of the first metacarpal commence to ossify, and they unite about the twen- 
tieth year. 
The Phalanges are each developed by two centres: one for the shaft, and one 
for the base. Ossification commences in the shaft, in all three rows, at about the 
eighth week, and gradually involves the whole of the bone excepting the upper 
extremity. Ossification of the base commences in the first row between the third 
and fourth years, and a year later in those of the second and third rows. The two 
centres become united in each row between the eighteenth and twentieth years. 
OF THE LOWER EXTREMITY. 
The Lower Extremity consists of three segments, the thigh, leg, and foot, 
which correspond to the arm, forearm, and hand in the upper extremity. It is 
connected to the trunk through the os innominatum, or haunch [or hip-bonef 
which forms the pelvic girdle. 
[Figs. 215 and 216 show the bones of the trunk in black, and those of the 
[Fig. 215. 
[Fig. 216. 
extremities shaded. Fig. 215 shows the shoulder girdle, and Fig. 216 the pelvic 
girdle, both from above. 
The shoulder girdle is imperfect in front, but the gap between the two clavicles 
is filled by the sternum; but it is absolutely imperfect behind, the gap between 
the two scapulas being unfilled, and the scapulae connected to the trunk wholly by 
Shoulder Girdle (Henle).] 
Pelvic Girdle (Henle).] 
1 Allan Thompson has demonstrated the fact that the first metacarpal bone is often developed 
from three centres-that is to say, there is a separate nucleus for the distal end, forming a distinct 
epiphysis visible at the age of seven or eight years. He also states that there are traces of a prox- 
imal epiphysis in the second metacarpal bone (Journal of Anatomy, 1869). 260 
THE SKELETON. 
muscles and by the clavicle. It is made up of two light, graceful, and very mov' 
able bones. 
The pelvic girdle is perfect in front, where the two innominate bones meet, and, 
though imperfect behind, the gap is filled up by the sacrum. The solidity and 
immobility of these strong bones are in marked contrast to the lightness and great 
mobility of the shoulder girdle, each being admirably fitted to its own purpose.] 
The Os Innominatum. 
The Os Innominatum (m, nomino, to name), or nameless bone, so called from 
bearing no resemblance to any known object, is a large, irregular-shaped bone 
Fig. 217. 
Anterior 
Superior 
Spin* 
xttrior 
Supcriur- 
Spine 
Anterior 
- luftrior 
Spin* 
Foster urr 
■Inferior- 
Spine 
Lint for 
Gimbtrnat's LICT. 
GEMELLUS superior 
Spine of Pulies 
for Pouparts LIGAMENT 
Spine <xf Lchio.ni.T-* 
Angle, ojPubes 
'RECTUS ABDOMINIS 
" PTHAMID ALLS 
CEDELLUS INFERIOR. 
Right Os Innominatum, external surface. 
which, with its fellow of the opposite side, forms the sides and anterior wall of the 
pelvic cavity. In young subjects it consists of three separate parts, which meet THE OS INNOMINATUM. 
261 
and form the large cup-like cavity situated near the middle of the outer side of the 
bone; and, although in the adult these have become united, it is usual to describe 
the bone as divisible into three portions-the ilium, the ischium, and the pubes. 
The Ilium, so called from its supporting the flank (ilia), is the superior broad 
and expanded portion which runs upward from the upper and back part of the 
acetabulum, and forms the prominence of the hip.Q1] 
The Ischium the hip) is the inferior and strongest portion of the bone; 
it proceeds downward from the acetabulum, expands into a large tuberosity, and 
then, curving upward, forms with the descending ramus of the pubes a large aper- 
ture, the obturator foramen. 
The Pubes is that portion which runs horizontally inward from the inner side 
of the acetabulum for about two inches, then makes a sudden bend and descends to 
the same extent: it forms the front of the pelvis, supports the external organs of 
generation, and has received its name from being covered with hair. 
The Ilium presents for examination two surfaces, an external and an internal, a 
crest, and two borders, an anterior and a posterior. 
External Surface or Dorsum of the Ilium (Fig. 217).-The back part of this 
surface is directed backward, downward, and outward; its front part forward, down- 
ward, and outward. It is smooth, convex in front, deeply concave behind; bounded 
above by the crest, below by the upper border of the acetabulum, in front and 
behind by the anterior and posterior borders. This surface is crossed in an arched 
direction by three semicircular lines-the superior, middle, and inferior curved lines. 
The superior curved line, the shortest of the three, commences at the crest, about 
two inches in front of its posterior extremity; it is at first distinctly marked, but as 
it passes downward and outward to the upper part of the great sacro-sciatic notch, 
where it terminates, it becomes less marked, and is often altogether lost. The rough 
surface included between this line and the crest affords attachment to part of the 
Gluteus maximus above and a few fibres of the Pyriformis below. The middle 
curved line, the longest of the three, commences at the crest, about an inch behind 
its anterior extremity, and, taking a curved direction downward and backward, ter- 
minates at the upper part of the great sacro-sciatic notch. The space between the 
middle and superior curved lines and the crest is concave, and affords attachment to 
the Gluteus medius muscle. Near the central part of this line may often be observed 
the orifice of a nutrient foramen. The inferior curved line, the least distinct of the 
three, commences in front at the upper part of the anterior inferior spinous process, 
and, taking a curved direction backward and downward, terminates at the middle 
of the great sacro-sciatic notch. The surface of bone included between the middle 
and inferior curved lines is concave from above downward, convex from before back- 
ward, and affords attachment to the Gluteus minimus muscle. Beneath the inferior 
curved line, and corresponding to the upper part of the acetabulum, is a smooth 
eminence (sometimes a depression) to which is attached the reflected tendon of the 
Rectus femoris muscle. 
The internal surface (Fig. 218) of the ilium is bounded above by the crest, 
below by a prominent line, the linea ilio-pectinea, and before and behind by the 
anterior and posterior borders. It presents anteriorly a large smooth, concave sur- 
face called the internal iliac fossa, or venter of the ilium, which lodges the Iliacus 
muscle, and presents at its lower part the orifice of a nutrient canal. Behind the 
iliac fossa is a rough surface divided into two portions, a superior and an inferior. 
The inferior or auricular surface, so called from its resemblance in shape to the 
ear, is coated with cartilage in the recent state, and articulates with a surface of 
similar shape on the side of the sacrum. The superior portion is concave and rough, 
for the attachment of the posterior sacro-iliac ligaments. 
The crest of the ilium is convex in its general outline and sinuously curved, 
being bent inward anteriorly, outward posteriorly. It is longer in the female than 
in the male, very thick behind, and thinner at the centre than at the extremities. 
f1 Note the difference in spelling between ilium, the bone, and ileum, the third part of the small 
intestine.] 262 
THE SKELETON. 
It terminates at either end in a prominent eminence, the anterior superior and the 
posterior superior spinous processes. The surface of the crest is broad, and divided 
into an external lip, an internal lip, and an intermediate space. To the external 
lip is attached the Tensor vaginae femoris, Obliquus externus abdominis, and Latis- 
simus dorsi, and by its whole length the fascia lata; to the interspace between the 
lips, the Internal oblique; to the internal lip, the Transversalis, Quadratus lum- 
Fig. 218. 
LEVATOR AN| 
ERECTOR £KNJ1 
COMPREfifiOe QHLEIHRM 
Right Os Imiominatum, internal surface. 
borum, and Erector spinae, the Iliacus, and the fascia iliaca. [In the very muscu- 
lar (e. g. Hercules) the great abdominal muscles overhang this crest.] 
The anterior border of the ilium is concave. It presents two projections, sepa- 
rated by a notch. Of these, the uppermost, situated at the junction of the crest 
and anterior border, is called the anterior superior spinous process of the ilium., the 
outer border of which gives attachment to the fascia lata and the origin of the 
Tensor vaginae femoris; its inner border, to the Iliacus; whilst its extremity affords THE OS INNOMINATUM. 
263 
attachment to Poupart's ligament and the origin of the Sartorius. [This anterior 
superior spine can always be felt, even in the very fat, and is one of the most 
important landmarks of the whole body. In all examinations for hernia, fracture, 
dislocation, etc. its position should be marked on the skin by an aniline pencil.] 
Beneath this eminence is a notch which gives attachment to the Sartorius muscle, 
and across which passes the external cutaneous nerve. Below the notch is the 
anterior inferior spinous process, which terminates in the upper lip of the acetab- 
ulum ; it gives attachment to the straight tendon of the Rectus femoris muscle 
and the ilio-femoral ligament. On the inner side of the anterior inferior spinous 
process is a broad shallow groove over which passes the Iliacus muscle. The pos- 
terior border of the ilium, shorter than the anterior, also presents two projections 
separated by a notch, the posterior superior and the posterior inferior spinous pro- 
cesses. The former corresponds with that portion of the posterior surface of the 
ilium which serves for the attachment of the oblique portion of the sacro-iliac liga- 
ments and the Multifidus spinse [it is always marked by a depression in the 
back, and in the female model this is a noticeable dimple, which adds much to its 
beauty] ; the latter to the auricular portion which articulates with the sacrum. 
Below the posterior inferior spinous process is a deep notch, the great sacro- 
sciatic. 
The Ischium forms the lower and back part of the os innominatum. It is 
divisible into a thick and solid portion, the body ; a large rough eminence on which 
the body rests in sitting, the tuberosity ; and a thin ascending part, the ramus. 
The body, somewhat triangular in form, presents three surfaces, external, inter- 
nal, and posterior. The external surface corresponds to that portion of the acetab- 
ulum formed by the ischium; it is smooth and concave, and forms a little more 
than two-fifths of the acetabular cavity; its outer margin is bounded by a promi- 
nent rim or lip to which the cotyloid fibro-cartilage is attached. Below the acetab- 
ulum, between it and the tuberosity, is a deep groove, along which the tendon of 
the Obturator externus muscle runs as it passes outward to be inserted into the 
digital fossa of the femur. The internal surface is smooth, concave, and forms the 
lateral boundary of the true pelvic cavity; it is broad above, and separated from 
the venter of the ilium by the linea ilio-pectinea; narrow below: its posterior 
border presents, a little below its centre, a sharp process, the spine of the ischium, 
above and below which are the greater and lesser sacro-sciatic notches; in front it 
presents a sharp margin, the internal border, which forms the outer boundary of the 
obturator foramen. This surface is perforated by two or three large vascular foram- 
ina, and affords attachment to part of the Obturator internus muscle. The pos- 
terior surface is quadrilateral in form, broad and smooth above, narrow below, 
where it becomes continuous with the tuberosity, and presents a portion of the 
same groove seen below the acetabulum for the tendon of the Obturator externus 
muscle; it is limited in front by the margin of the acetabulum; behind, by the 
front part of the great sacro-sciatic notch. This surface supports the Pyriformis, 
the two Gemelli, and the Obturator internus muscles in their passage outward to 
the great trochanter. The body of the ischium presents three borders, posterior, 
external, and internal. The posterior border presents a little below the centre a 
thin and pointed triangular eminence, the spine of the ischium, more or less elon- 
gated in different subjects. Its external surface gives attachment to the Gemellus 
superior, its internal surface to the Coccygeus and Levator ani, whilst to the pointed 
extremity is connected the lesser sacro-sciatic ligament. Above the spine is a notch 
of large size, the great sacro-sciatic, converted into a foramen by the lesser sacro- 
sciatic ligament; it transmits the Pyriformis muscle, the gluteal vessels, and supe- 
rior gluteal nerve passing out of the pelvis above the muscle; the sciatic vessels, 
the greater and lesser sciatic nerves, the internal pudic vessels and nerve, and mus- 
cular branches from the sacral plexus below it. Below the spine is a smaller notch, 
the lesser sacro-sciatic ; it is smooth, coated in the recent state with cartilage, the 
surface of which presents numerous markings corresponding to the subdivisions of 
the tendon of the Obturator internus which winds over it. It is converted into a 264 
THE SKELETON. 
foramen by the sacro-sciatic ligaments, and transmits the tendon of the Obturator 
internus, the nerve which supplies that muscle, and the internal pudic vessels and 
nerve. The external border forms the prominent rim of the acetabulum and sepa- 
rates the posterior from the external surface. To it is attached the cotyloid fibro- 
cartilage. The internal border is thin and forms the outer circumference of the 
obturator foramen. 
The tuberosity [upon which the body rests in the sitting posture] presents for 
examination an external lip, an internal lip, and an intermediate space. The exter- 
nal lip gives attachment to the Quadratus femoris and part of the Adductor magnus 
muscles. The inner lip is bounded by a sharp ridge, for the attachment of a falci- 
form prolongation of the great sacro-sciatic ligament; it presents a groove on the 
inner side of this, for the lodgment of the internal pudic vessels and nerve; and, 
more anteriorly, has attached the Transversus perinsei and Erector penis muscles. 
The intermediate surface is divided into two portions-an anterior, rough, somewhat 
triangular part, and a posterior, smooth, quadrilateral portion. The anterior sur- 
face is divided by a prominent vertical ridge, passing from base to apex, into two 
parts; the outer one gives attachment to the Adductor magnus, the inner to the 
great sacro-sciatic ligament. The posterior portion is also divided into two facets 
by an oblique ridge, which runs forward and outward; from the upper and outer 
facet arises the Semimembranosus; from the lower and inner, the Biceps and 
Semitendinosus. The uppermost part of the tuberosity gives attachment to the 
Gemellus inferior. 
The ramus or ascending ramus is the thin flattened part of the ischium which 
ascends from the tuberosity upward and inward, and joins the ramus of the pubes, 
their point of junction being indicated in the adult by a rough eminence. The 
outer surface of the ramus is rough, for the attachment of the Obturator externus 
muscle, also some fibres of the Adductor magnus and of the Gracilis; its inner 
surface forms part of the anterior wall of the pelvis. Its inner border is thick, 
rough, slightly everted, forms part of the outlet of the pelvis and presents two 
ridges and an intervening space. The ridges are continuous with similar ones on 
the descending ramus of the pubes. To the outer one is attached the deep layer 
of the superficial perineal fascia, and to the inner the anterior layer of the trian- 
gular ligament. If these two ridges are traced downward, they will be found to be 
continuous with each other at the anterior extremity of the tuberosity of the isch- 
ium ; here the two layers of fascia are blended behind the Transversus perinaei 
muscle. To the intervening space, just in front of the point of junction of the 
ridges, is attached the Transversus perinaei muscle, and in front of this a portion 
of the crus penis (vel clitoridis) and the Erector penis (vel clitoridis) muscle. Its 
outer border is thin and sharp, and forms part of the inner margin of the obturator 
foramen. 
The Pubes forms the anterior part of the os innominatum, and with the bone of 
the opposite side forms the front boundary of the true pelvic cavity. It is divisible 
into a body, a horizontal ramus, and a descending ramus. 
The body is somewhat quadrilateral in shape, and presents for examination two 
surfaces and three borders. The anterior surface is rough, directed forward and 
outward, and serves for the attachment of various muscles. To the upper and inner 
angle immediately below the crest is attached the Adductor longus; lower down, 
from without inward, are attached the Obturator externus, the Adductor magnus, 
the Adductor brevis, and the upper part of the Gracilis. The posterior surface, 
convex from above downward, concave from side to side, is smooth, and forms part 
of the anterior wall of the pelvis. It gives attachment to the Levator ani and 
Obturator internus. The upper border presents for examination a prominent 
tubercle which projects forward and is called the spine; to it is attached the outer 
pillar of the external abdominal ring and Poupart's ligament. Passing outward 
from this is a prominent ridge, forming part of the ilio-pectineal line, which, run- 
ning outward, marks the brim of the true pelvis. To it is attached a portion of 
the conjoined tendon of the Internal Oblique and Transversalis muscles, Gimbernat's THE OS INNO MINA T UM. 
265 
ligament, and the triangular ligament. Internal to the spine of the pubes is the 
crest, which extends from this process to the inner extremity of the bone. It 
affords attachment anteriorly to the conjoined tendon of the Internal Oblique and 
Transversalis, and posteriorly to the Rectus and Pyramidalis muscles. The point 
of junction of the crest with the inner border of the bone is called the angle; to 
it, as well as to the symphysis, is attached the internal pillar of the external abdom- 
inal ring. The internal border is the symphysis ; it is oval, covered by eight or 
nine transverse ridges, or a series of nipple-like processes arranged in rows sepa- 
rated by grooves; they serve for the attachment of the connecting fibro-cartilage 
placed between it and the opposite bone. The outer border presents a sharp mar- 
gin, which forms part of the circumference of the obturator foramen and affords 
attachment to the obturator membrane. 
The horizontal ramus extends from the body to the point of junction of the 
pubes with the ilium, and forms the upper part of the circumference of the obtu- 
rator foramen. It presents for examination a superior, inferior, and posterior sur- 
face and an outer extremity. The superior surface presents a continuation of the 
ilio-pectineal line, already mentioned as commencing on the body of the bone. In 
front of this ridge the surface of bone is triangular in form, wider externally than 
internally, smooth, and affords attachment to the Pectineus muscle. The surface is 
bounded externally by a rough eminence, the ilio-pectineal, which serves to indicate 
the point of junction of the ilium and pubes, and gives attachment to the Psoas 
parvus when this muscle is present. The inferior surface forms the upper bound- 
ary of the obturator foramen, and presents, externally, a broad and deep oblique 
groove, for the passage of the obturator vessels and nerve; and, internally, a sharp 
margin, which forms part of the circumference of the obturator foramen and to 
which the obturator membrane is attached. The posterior surface forms part of 
the anterior boundary of the true pelvis. It is smooth, convex from above down- 
ward, and affords attachment to the upper fibres of the obturator internus. The 
outer extremity, the thickest part of the ramus, forms one-fifth of the cavity of the 
acetabulum. 
The descending ramus of the pubes is thin and flattened. It passes outward 
and downward, becoming narrower as it descends, and joins with the ramus of the 
ischium. Its anterior surface is rough, for the attachment of muscles-the Gracilis 
along its inner border; a portion of the Obturator externus where it enters into the 
formation of the foramen of that name; and between these two muscles the Adduc- 
tores brevis and magnus. The posterior surface is smooth, for the Obturator inter- 
nus, and close to the inner margin the Compressor urethrae. The inner border is 
thick, rough, and everted, especially in females. It presents two ridges, separated 
by an intervening space. The ridges extend downward through the ascending 
ramus of the ischium to the tuber ischii, where they become continuous: to the 
external one is attached the deep layer of the superficial perineal fascia, and to the 
internal one the anterior layer of the triangular ligament. To the intervening 
space is attached the crus penis (vel clitoridis) and the Erector penis (vel clitoridis) 
muscle. The outer border is thin and sharp, forms part of the circumference of the 
obturator foramen, and gives attachment to the Obturator muscle. 
The Cotyloid Cavity, or Acetabulum, is a deep, cup-shaped, hemispherical 
depression formed, internally, by the pubes, above by the ilium, behind and below 
by the ischium, a little less than two-fifths being formed by the ilium, a little more 
than two-fifths by the ischium, and the remaining fifth by the pubes. It is bounded 
by a prominent uneven rim, which is thick and strong above, and serves for the 
attachment of a fibro-cartilaginous structure which contracts its orifice and deepens 
the surface for articulation. It presents on its inner side a deep notch, the cotyloid 
notch, which transmits the nutrient vessels into the interior of the joint, and is con- 
tinuous with a circular depression at the bottom of the cavity: this depression is 
perforated by numerous apertures, lodges a mass of fat, and its margins, as well as 
those of the notch, serve for the attachment of the ligamentum teres. The notch 
is converted, in the natural state, into a foramen by a dense ligamentous band which 266 
THE SKELETON. 
passes across it. Through this foramen the nutrient vessels and nerves enter the 
joint. [The internal surface of the pelvic bones is accessible to the touch by the 
rectum, and in women by the vagina also. In suspected hip-joint disease this may 
sometimes give valuable information by disclosing the condition of the floor of the 
acetabulum.] 
The Obturator or Thyroid Foramen is a large aperture situated between the 
ischium and pubes. In the male it is large, of an oval form, its longest diameter 
being obliquely from above downward; in the female it is smaller and more trian- 
gular. It is bound by a thin, uneven margin to which a strong membrane is attached, 
and presents at its upper and outer part a deep groove which runs from the pelvis 
obliquely forward, inward, and downward. This groove is converted into a foramen 
by the obturator membrane, and transmits the obturator vessels and nerve. 
Structure.-This bone consists of much cancellous tissue, especially where it is 
thick, enclosed between two layers of dense compact tissue. In the thinner parts 
of the bone, as at the bottom of the acetabulum and centre of the iliac fossa, it is 
usually semi-transparent and composed entirely of compact tissue. 
Development (Fig. 219).-By eight centres : three primary-one for the ilium, 
one for the ischium, and one for the pubes; and five secondary-one for the crest 
of the ilium, one for the anterior inferior spinous process (said to occur more fre- 
Fig. 219. 
Plan of the Development of the Os Innominatum, by eight centres-three primary (ilium, ischium, and pubes), 
live secondary. The three primary centres unite through a Y-shaped piece about puberty. Epiphyses appear 
about puberty, and unite about the twenty-fifth year. 
quently in the male than the female), one for the tuberosity of the ischium, one for 
the symphysis pubis (more frequent in the female than the male), and one for the 
Y-shaped piece at the bottom of the acetabulum. These various centres appear in 
the following order: First, in the ilium, at the lower part of the bone, immediately 
above the sciatic notch, at about the same period that the development of the verte- 
brae commences. Secondly, in the body of the ischium, at about the third month 
of foetal life. Thirdly, in the body of the pubes, between the fourth and .fifth THE PELVIS. 
267 
months. At birth the three primary centres are quite separate, the crest, the bot- 
tom of the acetabulum, and the rami of the ischium and pubes being still cartilagi- 
nous. At about the seventh or eighth year the rami of the pubes and ischium are 
almost completely ossified. About the thirteenth or fourteenth year the three divis- 
ions of the bone have extended their growth into the bottom of the acetabulum, 
being separated from each other by a Y-shaped portion of cartilage which now pre- 
sents traces of ossification. The ilium and ischium then become joined, and lastly 
the pubes, through the intervention of this Y-shaped portion. At about the age of 
puberty ossification takes place in each of the remaining portions, and they become 
joined to the rest of the bone about the twenty-fifth year. 
Articulations.-With its fellow of the opposite side, the sacrum, and femur. 
Attachment of Muscles.-To the ilium, fifteen. To the outer lip of the crest, 
the Tensor vagime femoris, Obliquus externus abdominis, and Latissimus dorsi; to 
the internal lip, the Iliacus, Transversalis, Quadratus lumborum, and Erector spinae; 
to the interspace between the lips, the Obliquus internus. To the outer surface of 
the ilium, the Gluteus maximus, Gluteus medius, Gluteus minimus, reflected tendon 
of Rectus, portion of Pyriformis; to the internal surface, the Iliacus, and the Mul- 
tifidus spinae to the internal surface of the posterior superior spine; to the anterior 
border, the Sartorius and straight tendon of the Rectus. To the ischium, fourteen. 
To its outer surface, the Obturator externus and Gracilis; internal surface, Obtura- 
tor internus and Levator ani. To the spine, the Gemellus superior, Levator ani, 
and Coccygeus. To the tuberosity, the Biceps, Semitendinosus, Semimembrano- 
sus, Quadratus femoris, Adductor magnus, Gemellus inferior, Transversus perinaei, 
Erectoi' penis. To the pubes, sixteen, the Obliquus externus, Obliquus inter- 
nus, Transversalis, Rectus, Pyramidalis, Psoas parvus, Pectineus, Adductor magnus, 
Adductor longus, Adductor brevis, Gracilis, Obturator externus and internus, Leva- 
tor ani, Compressor urethras, and occasionally a few fibres of the Accelerator urinae. 
The Pelvis, so called from its resemblance to a basin (L. pelvis}, is stronger and 
The Pelvis (Figs. 220, 221). 
Fig. 220. 
wore massively constructed than either the cranial or thoracic cavity; it is a bony 
Male Pelvis (adult). 268 
THE SKELETON. 
Fig. 221. 
Female Pelvis (adult). 
ring interposed between the lower end of the spine, which it supports, and the 
lower extremities, upon which it rests. It is composed of four bones: the two ossa 
innominata, which bound it on either side and in front, and the sacrum and coccyx, 
which complete it behind. 
The pelvis is divided by a prominent line, the linea ilio-pectinea, into the false 
and true pelvis. 
The False Pelvis is all that expanded portion of the pelvic cavity which is 
situated above the linea ilio-pectinea. It is bounded on each side by the ossa ilii; 
in front it is incomplete, presenting a wide interval between the spinous processes 
of the ilia on either side, which is filled up in the recent state by the parietes of 
the abdomen; behind, in the middle line, is a deep notch. This broad, shallow 
cavity is fitted to support the intestines and to transmit part of their weight to the 
anterior wall of the abdomen. 
The True Pelvis is all that part of the pelvic cavity which is situated beneath 
the linea ilio-pectinea. It is smaller than the false pelvis, but its walls are more 
perfect. For convenience of description it is divided into a superior circumference 
or inlet, an inferior circumference or outlet, and a cavity. 
The superior circumference forms the margin or brim of the pelvis, the 
included space being called the inlet. It is formed by the linea ilio-pectinea, com- 
pleted in front by the spine and crest of the pubes, and behind by the anterior 
margin of the base of the sacrum and sacro-vertebral angle. 
The inlet of the pelvis is somewhat heart-shaped, obtusely pointed in front, 
diverging on either side, and encroached upon behind by the projection forward of 
the promontory of the sacrum. It has three principal diameters-antero-posterior 
(sacro-pubic), transverse, and oblique. The antero-posterior extends from the sacro- 
vertebral angle to the symphysis pubis; its average measurement is four inches in 
the male, four and three-quarters in the female. The transverse extends across the 
greatest width of the inlet, from the middle of the brim on one side to the same 
point on the opposite; its average measurement is four and a half in the male, five 
and a quarter in the female. The oblique extends from the margin of the pelvis, 
corresponding to the ilio-pectineal eminence on one side, to the sacro-iliac symphy- 
sis on the opposite side; its average measurement is four and a quarter in the male 
and five in the female. 
The cavity of the true pelvis is bounded in front by the symphysis pubis; 
behind, by the concavity of the sacrum and coccyx, which, curving forward above THE PELVIS. 
269 
and below, contracts the inlet and outlet of the canal; and laterally it is bounded 
by a broad, smooth, quadrangular plate of bone corresponding to the inner surface 
of the body of the ischium. The cavity is shallow in front, measuring at the sym- 
physis an inch and a half in depth, three inches and a half in the middle, and four 
inches and a half posteriorly. From this description it will be seen that the cavity 
of the pelvis is a short curved canal, considerably deeper on its posterior than on its 
anterior wall, and broader in the middle than at either extremity, from the projec- 
tion forward of the sacro-coccygeal column above and below. This cavity contains, 
in the recent subject, the rectum, bladder, and part of the organs of generation. 
The rectum is placed at the back of the pelvis, and corresponds to the curve of the 
sacro-coccygeal column ; the bladder in front, behind the symphysis pubis. In the 
female the uterus and vagina occupy the interval between these parts. 
The lower circumference of the pelvis is very irregular, and forms what is 
called the outlet. It is bounded by three prominent eminences: one posterior, 
formed by the point of the coccyx; and one on each side, the tuberosities of the 
ischia. These eminences are separated by three notches: one in front, the pubic 
arch, formed by the convergence of the rami of the ischia and pubes on each side; 
the other notches, one on each side, are formed by the sacrum and coccyx behind, 
the ischium in front, and the ilium above: they are called the sacro-sciatic notches; 
in the natural state they are converted into foramina by the lesser and greater sacro- 
sciatic ligaments. 
The diameters of the outlet of the pelvis are two, antero-posterior and transverse. 
The antero-posterior extends from the tip of the coccyx to the lower part of the 
symphysis pubis; its average measurement is three and a quarter inches in the male 
and five in the female. The transverse extends from the posterior part of one 
ischiatic tuberosity to the same point on the opposite side; the average measurement 
is three and a half inches in the male and four and three-quarters in the female. The 
antero-posterior diameter varies with the length of the coccyx, and is capable of 
increase or diminution on account of the mobility of that bone. 
Position of the Pelvis.-In the erect posture the pelvis is placed obliquely with 
regard to the trunk of the body: the bony ring, which separates the true from the 
false pelvis, and which forms the essential part of the pelvis, is placed so as to form 
an angle of about sixty to sixty-five degrees with 
the ground on which we stand. The pelvic surface 
of the symphysis pubis looks upward and back- 
ward, the concavity of the sacrum and coccyx 
downward and forward, the base of the sacrum in 
well-formed female bodies being nearly four inches 
above the upper border of the symphysis pubis, 
and the apex of the coccyx a little more than half 
an inch above its lower border. The obliquity is 
much greater in the foetus and at an early period 
of life than in the adult. In consequence of this 
obliquity of the pelvis the line of gravity of the 
head, which passes through the middle of the 
odontoid process of the axis and through the 
points of junction of the curves of the vertebral 
column to the sacro-vertebral angle, descends to- 
ward the front of the cavity, so that it bisects a 
line drawn transversely through the middle of the 
heads of the thigh-bones. And thus the centre of 
gravity of the head is placed immediately over the 
heads of the thigh-bones on which the trunk is 
supported. 
Axes of the Pelvis (Fig. 222).-The plane of the inlet of the true pelvis will 
be represented by a line drawn from the base of the sacrum to the upper margin 
of the symphysis pubis. [This forms with the horizon an angle of from fifty -five 
Fig. 222. 
Vertical Section of the Pelvis, with lines 
indicating the axes of the pelvis. 270 
THE SKELETON. 
to sixty-five degrees.] A line carried at right angles with this at its middle would 
correspond at one extremity with the umbilicus, and at the other with the middle of 
the coccyx : the axis of the inlet is therefore directed downward and backward. 
EThe plane of the outlet is represented by a line from the tip of the coccyx to the 
ower border of the symphysis, and forms with the horizon an angle, varying with 
the length of the coccyx, of from seven to twenty-seven degrees.] The axis of the 
outlet produced upward would touch the base of the sacrum, and is therefore directed 
downward and forward. [This axis is directed downward and backward, not forward, 
the tip of the coccyx being above the level of the lower border, and often of the 
upper border, of the symphysis.] The axis of the cavity is curved like the cavity 
itself: this curve corresponds to the concavity of the sacrum and coccyx, the extremi- 
ties being indicated by the central points of the inlet and outlet. A knowledge of 
the direction of these axes serves to explain the course of the foetus in its passage 
through the pelvis during parturition. It is also important to the surgeon, as 
indicating the direction of the force required in the removal of calculi from the 
bladder, and as determining the direction in which instruments should be used in 
operations upon the pelvic viscera. 
Differences between the Male and Female Pelvis.-In the male the bones 
are thicker and stronger, and the muscular eminences and impressions on their sur- 
faces more strongly marked. The male pelvis is altogether more massive ; its cav- 
ity is deeper and narrower and the obturator foramina of larger size. In the female 
the bones are lighter and more expanded, the muscular impressions on their surfaces 
are only slightly marked, and the pelvis generally is less massive in structure. The 
iliac fossae are broad, and the spines of the ilia widely separated; hence the great 
prominence of the hips. The inlet and the outlet are larger, the former being 
more nearly circular in consequence of the sacral promontory projecting less into 
it. The cavity is more capacious, and the spines of the ischia project less into it. 
The promontory is less projecting, the sacrum wider and less curved,1 and the coc- 
cyx more movable. The arch of the pubes is wider and its edges more everted. 
[This subpubic arch is in the male an angle rather than an arch, and usually meas- 
ures about seventy-five degrees, but may be much less; in women it is a true arch, 
and subtends an angle of ninety to one hundred degrees. A narrow subpubic arch 
in men brings the tuberosities of the ischia together, and is a serious impediment in 
lithotomy ; while in women the same narrowness would greatly impede delivery, and 
if too marked make normal birth impossible.] The tuberosities of the ischia and 
the acetabula are wider apart. 
The size of the pelvis varies not only in the two sexes, but also in different 
members of the same sex. This does not appear to be influenced in any way by 
the height of the individual. Women of short stature, as a rule, have broad pelves. 
Occasionally the pelvis is equally contracted in all its dimensions, so much so that 
all its diameters measure an inch less than the average, and this even in women of 
average height and otherwise well formed. The pelvis of the negro is said to be 
smaller than that of the European, and the sacrum is somewhat less curved. 
In the foetus and for several years after birth the pelvis is small in proportion 
to that of the adult. The cavity is deep and the projection of the sacro-vertebral 
angle less marked. The antero-posterior and transverse diameters are nearly equal. 
About puberty the pelvis in both sexes presents the general characters of the adult 
male pelvis, but after puberty it acquires its proper sexual characters. 
The Femur or Thigh-bone. 
The Femur (femur, the thigh) is the longest,2 largest, and strongest bone in the 
skeleton, and almost perfectly cylindrical in the greater part of its extent. In the 
erect posture it is not vertical, being separated from its fellow above by a consider- 
able interval, which corresponds to the entire breadth of the pelvis, but inclining 
1 It is not unusual, however, to find the sacrum in the female presenting a considerable curve 
extending throughout its whole length. 
2 In a man six feet high it measures eighteen inches-one-fourth of the whole body. THE FEMUR OR THIGH-BONE. 
271 
gradually downward and inward, so as to approach its fellow toward its lower part, 
for the purpose of bringing the knee-joint near the line of gravity of the body. 
The degree of this inclination varies in different persons, and is greater in the 
female than in the male, on account of the greater breadth of the pelvis. [Com- 
pare remarks on the difference between the knee- and elbow-joints, p. 242.] The 
femur, like other long bones, is divisible into a shaft and two extremities. 
The Upper Extremity presents for examination a head, a neck, and the greater 
and lesser trochanters. 
The head, which is globular and forms rather more than a hemisphere, is directed 
upward, inward, and a little forward, the greater part of its convexity being above 
and in front. Its surface is smooth, coated with cartilage in the recent state, and 
presents, a little behind and below its centre, an ovoid depression, for the attach- 
ment of the ligamentum teres. The neck is a flattened pyramidal process of bone 
which connects the head with the shaft. It varies in length and obliquity at vari- 
ous periods of life and under different circumstances. In infancy the angle is widest, 
and becomes lessened during growth, so that at puberty it forms a gentle curve from 
the axis of the shaft. In the adult it forms an angle of about one hundred and thirty 
degrees with the shaft, but varies in inverse proportion to the development of the 
pelvis and the stature. In consequence of the prominence of the hips and widen- 
ing of the pelvis in the female the neck of the thigh-bone forms more nearly a 
right angle with the shaft than it does in man. It has been stated that the angle 
diminishes in old age and the direction of the neck becomes horizontal, but this 
statement is founded on insufficient evidence. Professor Humphry states that he 
has not had the opportunity of making sufficient measurements to settle the ques- 
tion, but, so far as his observation goes, " the change is the exception rather than 
the rule." 1 The neck is flattened from before backward, contracted in the middle, 
and broader at its outer extremity, where it is connected with the shaft, than at its 
summit, where it is attached to the head. The vertical diameter of the outer half 
is increased by the thickening of the lower edge, which slopes downward to join the 
shaft at the lesser trochanter, so that the outer half of the neck is flattened from 
before backward, and its vertical diameter measures one-third more than the antero- 
posterior. The inner half is smaller and of a more circular shape. The anterior 
surface of the neck is perforated by numerous vascular foramina. The posterior 
surface is smooth, and is broader and more concave than the anterior; it gives 
attachment externally to the posterior part of the capsular ligament of the hip- 
joint. The superior border is short and thick, bounded externally by the great 
trochanter, and its surface perforated by large foramina. The inferior border, long 
and narrow, curves a little backward, to terminate at the lesser trochanter.2 
The Trochanters (pgoyaa), to run or roll) are prominent processes of bone which 
afford leverage to the muscles which rotate the thigh on its axis. They are two in 
number, the greater and the lesser. 
The Great Trochanter is a large, irregular, quadrilateral eminence situated at 
the outer side of the neck, at its junction with the upper part of the shaft. It is 
directed a little outward and backward, and in the adult is about three-quarters of 
an inch lower than the head. It presents for examination two surfaces and four 
borders. The external surface, quadrilateral in form, is broad, rough, convex, and 
marked by a prominent diagonal line, which extends from the posterior superior to 
the anterior inferior angle; this line serves for the attachment of the tendon of the 
Gluteus medius. Above the line is a triangular surface, sometimes rough for part 
of the tendon of the same muscle, sometimes smooth for the interposition of a bursa 
between that tendon and the bone. Below and behind the diagonal line is a smooth 
triangular surface over which the tendon of the Gluteus maximus muscle plays, a 
bursa being interposed. The internal surface is of much less extent than the 
external, and presents at its base a deep depression, the digital or trochanteric 
fossa, for the attachment of the tendon of the Obturator externus muscle. The 
1 See Old Age, and Changes Incidental to It, p. 25. 
[2For a description ol the "true neck" of the femur see Bigelow On the Hip, p. 123.] 272 
THE SKELETON. 
OBTURATOR INTERNUS QEMELLl 
PVRIFORMIS 
superior border is free; it is thick 
and irregular, and marked by 
impressions, for the attachment 
of the Pyriformis behind, the 
Obturator internus and Gemelli 
in front. The inferior border 
corresponds to the point of junc- 
tion of the base of the trochanter with the 
outer surface of the shaft; it is marked by a 
rough, prominent, slightly curved ridge which 
gives attachment to the upper part of the 
Vastus externus muscle. The anterior border 
is prominent, somewhat irregular, as well as 
the surface of bone immediately below ift; it 
affords attachment by its outer part to the 
Gluteus minimus. The posterior border is 
very prominent, and appears as a free rounded 
edge which forms the back part of the digital 
fossa. [The great trochanter can be readily 
felt at the anterior part of a marked hollow 
at the side of the buttock, and its rotation and 
other movements observed here. The top of 
it just touches a line, called " Ndlaton's line," 
drawn from the anterior-superior spine of the 
ilium to the tuberosity of the ischium. These 
points are extremely useful in relation to frac- 
tures and dislocations of the femur.] 
The Lesser Trochanter is a conical emi- 
nence which varies in size in different subjects; 
it projects from the lower and back part of 
the base of the neck. Its base is triangular, 
and connected with the adjacent parts of the 
bone by three well-marked borders: two of 
these are above-the internal continuous with 
the lower bordei- of the neck ; the external, 
with the posterior intertrochanteric line, while 
the inferior border is continuous with the mid- 
dle division of the linea aspera. Its summit, 
which is directed inward and backward, is 
rough, and gives insertion to the tendon of 
the Psoas magnus. The Iliacus is inserted 
into the shaft below the lesser trochanter, be- 
tween the Vastus internus in front and the 
Pectineus behind. A well-marked prominence 
of variable size, which projects from the upper 
and front part of the neck at its junction with 
the great trochanter, is called the tubercle of 
the femur; it is the point of meeting of five 
muscles-the Gluteus minimus externally, the 
Vastus externus below, and the tendon of the 
Obturator internus and Gemelli above. Run- 
ning obliquely downward and inward from the 
tubercle is the spiral line of the femur, or an- 
terior intertrochanteric line; it winds round 
the inner side of the shaft, below the lesser 
trochanter, and terminates in the linea aspera, 
about two inches below this eminence. Its 
■Fig. 223. 
. De/mnrton. for 
UC4MENTUM TEAU3 
Kight Femur, anterior surface. THE FEMUR OR THIGH-BONE. 
273 
upper half is rough, and affords 
attachment to the capsular liga- 
ment of the hip-joint; its lower 
half is less prominent, and gives 
attachment to the upper part of 
the Vastus internus. Running 
obliquely downward and inward 
from the summit of the great tro- 
chanter on the posterior surface 
of the neck is a very prominent, 
well-marked ridge, the posterior 
intertrochanteric line. Its upper 
half forms the posterior border of 
the great trochanter, and its lower 
half runs downward and inward 
across the neck of the bone to the 
upper and back part of the lesser 
trochanter. A slight ridge some- 
times commences about the middle 
of the posterior intertrochanteric 
line, and passes vertically down- 
ward for about two inches along 
the back part of the shaft; it is 
called the linea quadratic and 
gives attachment to the Quad- 
ratus femoris and a few fibres of 
the Adductor magnus muscles.1 
The shaft, almost perfectly 
cylindrical in form, is a little 
broader above than in the cen- 
tre, and somewhat flattened from 
before backward below. It is 
slightly arched, so as to be convex 
in front-concave behind, where 
it is strengthened by a prominent 
longitudinal ridge, thelineaaspera. 
It presents for examination three 
borders, separating three surfaces. 
Of the three borders, one, the linea 
aspera, is posterior; the other two 
are placed laterally. 
The linea aspera (Fig. 224) 
is a prominent longitudinal ridge 
or crest, presenting on the middle 
third of the bone an external lip, 
an internal lip, and a rough inter- 
mediate space. A little above the 
centre of the shaft this crest di- 
vides into three lines;2 the most 
Fig. 224. 
.OBTURATOR EXTERNUS 
-Adductor Ttibercle 
1 Generally there is merely a slight 
thickening about the centre of the inter- 
trochanteric line, marking the point of 
attachment of the Quadratus femoris. 
This is termed by some anatomists the 
tubercle of the quadratus. 
2 Of these three lines, only the outer 
and inner are described by many anat- 
omists : the linea aspera is then said to 
bifurcate above and below. 
Cr'roove.for tendoiu 
P0PL1TEUS 
Right Femur, posterior surface. 274 
THE SKELETON. 
external one becomes very rough, and is continued almost vertically upward to the 
base of the great trochanter; the middle one, the least distinct, is continued to the 
base of the trochanter minor; and the internal one is lost above in the spiral line 
of the femur. Below, the linea aspera divides into two ridges, which enclose between 
them a triangular space, the popliteal space, upon which rests the popliteal artery. 
Of these two ridges, the outer one is the more prominent and descends to the summit 
of the outer condyle. The inner one is less marked, especially at its upper part, 
where it is crossed by the femoral artery. It terminates below, at the summit of 
the internal condyle, in a small tubercle, the adductor tubercle, which affords attach- 
ment to the tendon of the Adductor magnus. 
To the inner lip of the linea aspera, along its whole length, is attached the 
Vastus internus, and to the whole length of the outer lip, the Vastus externus. The 
Adductor magnus is also attached to the whole length of the linea aspera, being 
connected with the outer lip above and the inner lip below. Between the Vastus ex- 
ternus and the Adductor magnus are attached two muscles-viz. the Gluteus maxi- 
mus above and the short head of the Biceps below. Between the Adductor magnus 
and the Vastus internus four muscles are attached: the Iliacus and Pectineus above 
(the latter to the middle of the upper divisions); below these the Adductor brevis 
and Adductor longus. The linea aspera is perforated a little below its centre by 
the nutrient canal, which is directed obliquely upward. 
The two lateral borders of the femur are only slightly marked, the outer one 
extending from the anterior inferior angle of the great trochanter to the anterior 
extremity of the external condyle; the inner one from the spiral line, at a point 
opposite the trochanter minor, to the anterior extremity of the internal condyle. 
The internal border marks the limit of attachment of the Crureus muscle internally. 
The anterior surface includes that portion of the shaft which is situated 
between the two lateral borders. It is smooth, convex, broader above and 
below than in the centre, slightly twisted, so that its upper part is directed 
forward and a little outward, its lower part forward and a little inward. To 
the upper three-fourths of this surface the Crureus is attached; the lower fourth 
is separated from the muscle by the intervention of the synovial membrane of the 
knee-joint, and affords attachment to the Subcrureus to a small extent. The exter- 
nal surface includes the portion of bone between the external border and the outer 
lip of the linea aspera; it is continuous above with the outer surface of the great 
trochanter; below with the outer surface of the external condyle: to its upper 
three-fourths is attached the outer portion of the Crureus muscle. The internal 
surface includes the portion of bone between the internal border and the inner lip 
of the linea aspera; it is continuous above with the lower border of the neck ; 
below, with the inner side of the internal condyle: it is covered by the Vastus 
internus muscle. 
The Lower Extremity, larger than the upper, is of a cuboid form, flattened 
from before backward, and divided into two large eminences, the condyles (xbvooloq, 
a knuckle), by an interval which presents a smooth depression in front called the 
trochlea, and a notch of considerable size behind-the intercondyloid notch. The 
external condyle is the more prominent anteriorly, and is the broader both in the 
antero-posterior and transverse diameters. The internal condyle is the narrower, 
longer, and more prominent inferiorly. This difference in the length of the two 
condyles is only observed when the bone is perpendicular, and depends upon the 
obliquity of the thigh-bones in consequence of their separation above at the articu- 
lation with the pelvis. If the femur is held obliquely, the surfaces of the two con- 
dyles will be seen to be nearly horizontal. The two condyles are directly contin- 
uous in front, and form a smooth trochlear surface, the external border of which is 
more prominent and ascends higher than the internal one. This surface articulates 
with the patella. It presents a median groove which extends downward and back- 
ward to the intercondyloid notch, and two lateral convexities, of which the external 
is the broader, more prominent, and prolonged farther upward upon the front of 
the outer condyle. The intercondyloid notch lodges the crucial ligaments; it is THE FEMUR OR THIGH-BONE. 
275 
bounded laterally by the opposed surfaces of the two condyles, and in front by the 
lower end of the shaft. 
Outer Condyle.-The outer surface of the external condyle presents, a little 
behind its centre, an eminence, the outer tuberosity; it is less prominent than the 
inner tuberosity, and gives attachment to the external lateral ligaments of the 
knee. Immediately beneath it is a groove which commences at a depression a 
little behind the centre of the lower border of this surface: the depression gives 
origin to the Popliteus muscle, the tendon of which is lodged in the groove, which 
is smooth, covered with cartilage in the recent state, and runs upward and back- 
ward to the posterior extremity of the condyle. The inner surface of the outer 
condyle forms one of the lateral boundaries of the intercondyloid notch, and gives 
attachment by its posterior part to the anterior crucial ligament. The inferior sur- 
face is convex, smooth, and broader than that of the internal condyle. The pos- 
terior extremity is convex and smooth : just above the articular surface is a depres- 
sion for the tendon of the outer head of the Gastrocnemius, above which is the 
origin of the Plantaris. 
Inner Condyle.-The inner surface of the inner condyle presents a convex 
eminence, the inner tuberosity, rough, for the attachment of the internal lateral 
ligament. The outer side of the inner condyle forms one of the lateral boundaries 
of the intercondyloid notch, and gives attachment by its anterior part to the pos- 
terior crucial ligament. Its inferior or articular surface is convex, and presents a 
less extensive surface than the external condyle. Just above the articular surface 
of the condyle, behind, is a depression for the tendon of origin of the inner head 
of the Gastrocnemius. 
[" The inner aspect of the internal condyle in every position of the limb faces 
nearly in the direction of the head of the femur" (Bigelow). 
The careful external study of the knee on the living model is of the greatest 
use. The patellar groove and its borders, a large part of the articular surfaces of 
the femur and tibia, the groove between them, and most of the bony prominences 
on all the bones, and the varying positions of the patella, can be easily noticed. 
It should 6e studied both in extension and various degrees of flexion.] 
Structure.-The shaft of the femur is a cylinder of compact tissue hollowed by 
a large medullary canal. The cylinder is of great thickness and density in the 
middle third of the shaft, where the bone is narrowest and the medullary canal well 
formed; but above and below this the cylindei' gradually becomes thinner, owing 
to a separation of the layers of the bone into cancelli, which project into the medul- 
lary canal, and finally obliterate it, so that the 
upper and lower ends of the shaft, and the 
articular extremities more especially, consist 
of cancellated tissue invested by a thin, com- 
pact layer. 
The arrangement of the cancelli in the 
ends of the femur is remarkable. In the 
upper end (Fig. 225) they run in parallel 
columns, a, a, from the summit of the head to 
the under wall of the neck, while a series of 
transverse fibres, b, b, cross the parallel col- 
umns and connect them to the upper wall of 
the neck. Another series of plates, c, c, springs 
from the whole interior of the cylinder above 
the lesser trochanter; these pass upward, and 
converge to form a series of arches beneath 
the upper wall of the neck near its junction 
with the great trochanter. This structure is 
admirably adapted to sustain, with the great- 
est mechanical advantage, concussion or weight transmitted from above, and serves 
an important office in strengthening a part especially liable to fracture. 
Fig. 225. 
Diagram showing the Structure of the Neck 
of the Femur (after Ward). 276 
THE SKELETON. 
In the lower end the cancelli spring on all sides from the inner surface of the 
cylinder, and descend in a perpendicular direction to the articular surface, the can- 
celli being strongest and having a more accurately perpendicular course above the 
condyles. 
Articulations.-With three bones: the os innominatum, tibia, and patella. 
Development (Fig- 226).-The femur is developed by five centres : one for the 
shaft, one for each extremity, and one for each trochanter. Of all the long bones 
except the clavicle, it is the first to 
show traces of ossification; this com- 
mences in the shaft at about the fifth 
week of foetal life, the centres of ossi- 
fication in the epiphyses appearing in 
the following order : First, in the lower 
end of the bone at the ninth month of 
foetal life; from this the condyles and 
tuberosities are formed; in the head, 
at the end of the first year after birth; 
in the great trochanter, during the 
fourth year; and in the lesser tro- 
chanter, between the thirteenth and 
fourteenth. The order in which the 
epiphyses are joined to the shaft is the 
reverse of that of their appearance: 
their junction does not commence until 
after puberty, the lesser trochanter be- 
ing first joined, then the greater, then 
the head, and lastly the inferior ex- 
tremity (the first in which ossification 
commenced), which is not united until 
the twentieth year. [The growth of the 
femur in length is greatest at the junc- 
tion of the shaft with the inferior 
epiphysis, owing to its late ossification. 
While the entire body grows from birth 
to thirty years of age 3.37 times, the 
growth at the lower end of the femur 
is 7.30 times, the greatest in the entire 
body. This should make the surgeon cautious, in resection of the knee in children, 
not to disturb the epiphysial cartilage if at all possible, in order to interfere as little 
as may be with the growth of the leg. . This is especially important in girls, on 
account of its possible influence on the pelvis.] 
Attachment of Muscles.-To twenty-three: to the great trochanter, the 
Gluteus medius, Gluteus minimus, Pyriformis, Obturator internus, Obturator 
externus, Gemellus superior, Gemellus inferior, and Quadratus femoris. To the 
lesser trochanter, the Psoas magnus and the Iliacus below it. To the shaft, the 
Vastus externus, Gluteus maximus, short head of the Biceps, Vastus internus, 
Adductor magnus, Pectineus, Adductor brevis, Adductor longus, Crureus, and 
Subcrureus. To the condyles, the Gastrocnemius, Plantaris, and Popliteus. 
Fig. 226. 
Appears at l$yT 
J-Shaft about Why? 
i Appears at end ■' 
* Joins Shaft about 18^y1. 
Appears 18 
Joins Shrift about y? 
App ea rs at Q 
L 1 (fcetccl / 
Joins Shaft at 
Plan of the Development of the Femur, by five centres. 
THE LEG-. 
The skeleton of the Leg consists of three bones: the Patella, a large sesamoid 
bone placed in front of the knee, and the Tibia and Fibula. THE PATELLA. 
277 
The Patella (Figs. 227, 228). 
The Patella (patella, a small pan) is a flat, triangular bone situated at the 
anterior part of the knee-joint. It 
is usually regarded as a sesamoid 
bone developed in the tendon of 
the Quadriceps extensor. It re- 
sembles these bones in its struc- 
ture, being composed mainly of 
dense cancellous tissue, and in its 
development, the nucleus present- 
ing a knotty or tuberculated outline 
similar to other sesamoid bones. 
It serves to protect the front of 
the joint, and increases the lev- 
erage of the Quadriceps extensor 
by making it act at a greater angle. It presents an anterior and posterior surface, 
three borders, and an apex. 
The anterior surface is convex, perforated by small apertures for the passage 
of nutrient vessels, and marked by numerous rough longitudinal striae. This sur- 
face is covered, in the recent state, by an expansion from the tendon of the Quadri- 
ceps extensor, which is continuous below with the superficial fibres of the ligamen- 
tum patellae. It is separated from the integument by a bursa. The posterior sur- 
face presents a smooth, oval-shaped, articular surface covered with cartilage in the 
recent state, and divided into two facets by a vertical ridge, wrhich descends from 
the superior toward the inferior angle of the bone. The ridge corresponds to the 
groove on the trochlear surface of the femur, and the two facets to the articular sur- 
faces of the two condyles; the outer facet, for articulation with the outer condyle, 
being the broader and deeper. This character serves to indicate the side to which 
the bone belongs. In a well-marked bone these two articular surfaces may be seen 
to be divided into three distinct facets by two transverse ridges which pass outward 
from the central vertical ridges. Of these, the middle one is the largest; it is con- 
cave from above downward and occupies two-thirds of the surface. This part rests 
against the prominent condyles of the femur when the joint is in the mid-position 
between flexion and extension. Above and below this are narrow, flat facets 
separated by the transverse ridges, which respectively rest against the condyles in 
the extended and flexed positions of the joint. Below the articular surface is a 
rough, convex, non-articular depression, the lower half of which gives attachment 
to the ligamentum patellse, the upper half being separated from the head of the 
tibia by adipose tissue. 
The superior border is thick, directed upward, and cut obliquely at the expense 
of its anterior surface; it gives attachment to that portion of the Quadriceps exten- 
sor which is derived from the Rectus and Crureus muscles. The lateral borders are 
thinner, converging below. They give attachment to that portion of the Quadriceps 
extensor derived from the external and internal Vasti muscles. According to Good- 
sir, the inner border is marked posteriorly by a narrow marginal facet, which is cut 
off from the rest of the articular surface by a slightly marked vertical ridge. This 
facet rests against the outer border of the inner condyle during flexion of the knee. 
The apex is pointed, and gives attachment to the ligamentum patellse. 
[In the model, when the leg is entirely extended, the patella is very movable, 
but so soon as flexion begins it is fixed in its groove. It is always in contact with 
the femur in extension, unless separated from it by an accumulation of fluid inside 
the joint. In periarticular accumulation of pus or other fluid this floating of the 
patella will not take place. Its varying positions and relations in different degrees 
of flexion are important and can readily be studied.] 
Structure.-It consists of a nearly uniform, dense cancellous tissue covered by 
a thin, compact lamina. The cancelli immediately beneath the anterior surface are 
Fig. 227. 
Fig. 228. 
Right Patella, anterior surface. 
Posterior Surface. 278 
THE SKELETON. 
Fig. 229. 
arranged parallel with it. In the rest 
of the bone they radiate from the 
posterior articular surface toward the 
other parts of the bone. 
Development.-By a single cen- 
tre, which makes its appearance, ac- 
cording to about the third 
year. In two instances I have seen 
this bone cartilaginous throughout at 
a much later period (six years). More 
rarely, the bone is developed by two 
centres, placed side by side. Ossifi- 
cation is completed about the age of 
puberty. 
Articulations.-With the two 
condyles of the femur. 
Attachment of Muscles.-To 
four: the Rectus, Crureus, Vastus 
internus, and Vastus externus. 
These muscles, joined at their in- 
sertion, constitute the Quadriceps ex- 
tensor cruris. 
Ct (£ 
SiyWiT' prceo^ 
Latcra L- 
lio. 
FIBULA 
TIBIA 
The Tibia (Figs. 229, 230). 
The Tibia (tibia, a flute or pipe) 
is situated at the front and inner side 
of the leg, and, excepting the femur, 
is the longest and largest bone in the 
skeleton. It is prismoid in form, ex- 
panded above, where it enters into the 
knee-joint, more slightly enlarged be- 
low. In the male its direction is ver- 
tical and parallel with the bone of the 
opposite side; but in the female it has 
a slight oblique direction downward 
and outward, to compensate for the 
oblique direction of the femur in- 
ward. It presents for examination 
a shaft and two extremities. 
The Upper Extremity, or head, 
is large and expanded on each side 
into two lateral eminences, the tube- 
rosities. Superiorly, the tuberos- 
ities present two smooth, concave 
surfaces, which articulate with the 
condyles of the femur; the internal 
articular surface is longer and deeper, 
but narrower, than the external, and 
oval from before backward, to artic- 
ulate with the internal condyle ; the 
external one being broader, flatter, 
and more circular, to articulate with 
the external condyle. Between the 
two articular surfaces, and nearer the 
posterior than the anterior aspect of 
the bone, is an eminence, the spinous process of the tibia, surmounted by a prominent 
Hsr.L&riLiil Malleolus 
lutumaJ, -frlalltaluv 
Bones of the Right Leg, anterior surface. THE TIBIA. 
279 
tubercle on each side, which gives attachment to the extremities of the semilunar 
fibro-cartilages; in front and behind the spinous process is a rough depression, for 
the attachment of the anterior and 
posterior crucial ligaments and the 
semilunar cartilages. The ante- 
rior surfaces of the tuberosities 
are continuous with one another, 
forming a single large surface 
which is somewhat flattened: it is 
triangular, broad above, and per- 
forated by large vascular foramina; 
narrow below, where it terminates 
in a prominent oblong elevation of 
large size, the tubercle of the tibia: 
the lower half of this tubercle is 
rough, for the attachment of the 
ligamentum patellae; the upper 
half is a smooth facet, corre- 
sponding, in the recent state, with 
a bursa which separates the liga- 
ment from the bone. Posteriorly, 
the tuberosities are separated from 
each other by a shallow depres- 
sion, the popliteal notch, which 
gives attachment to part of the 
posterior crucial ligament and part 
of the posterior ligament of the 
knee-joint. The posterior surface 
of the inner tuberosity presents 
a deep transverse groove, for the 
insertion of one of the fasciculi of 
the tendon of the Semimembra- 
nosus. The lateral surfaces are 
convex and rough: the internal 
one, the most prominent, gives 
attachment to the internal lateral 
ligament, and is marked by a 
groove, for the insertion of the 
innermost fasciculus of the tendon 
of the Semimembranosus. The 
external surface is the least prom- 
inent; it presents posteriorly a flat 
articular facet, nearly circular in 
form, directed downward, back- 
ward, and outward, for articula- 
tion with the fibula. In front it 
presents a prominent rough emi- 
nence situated on a level with the 
upper border of the tubercle of 
the tibia, for the attachment of 
the ilio-tibial band. Just below 
this the Extensor longus digito- 
rum and a slip from the Biceps 
are attached. 
The Shaft of the tibia is of a 
triangular prismoid form, broad 
above, gradually decreasing in 
Fig. 230. 
-Styloidprocess 
FIBULA 
TIBIA 
Bones of the Right Leg, posterior surface. 280 
THE SKELETON. 
size to its most slender part, at the commencement of its lower fourth, where frac- 
ture most frequently occurs; it then enlarges again toward its lower extremity. It 
presents for examination three surfaces and three borders. 
The anterior border, the most prominent of the three, is called the crest of the 
tibia, or, in popular language, the shin; it commences above at the tubercle, and 
terminates below at the anterior margin of the inner malleolus. This border is very 
prominent in the upper two-thirds of its extent, smooth and rounded below. It 
presents a very flexuous course, being curved outward above and inward below; it 
gives attachment to the deep fascia of the leg. 
The internal border is smooth and rounded above and below, but more promi- 
nent in the centre ; it commences at the back part of the inner tuberosity, and termi- 
nates at the posterior border of the internal malleolus; its upper part gives attach- 
ment to the internal lateral ligament of the knee to the extent of about two inches, 
and to some fibres of the Popliteus muscle; its middle third, to some fibres of the 
Soleus and Flexor longus digitorum muscles. 
The external border, or interosseous ridge, is thin and prominent, especially 
its central part, and gives attachment to the interosseous membrane; it commences 
above in front of the fibular articular facet, and bifurcates below to form the bound- 
aries of a triangular rough surface, for the attachment of the interosseous ligament 
connecting the tibia and fibula. 
The internal surface is smooth, convex, and broader above than below; its 
upper third, directed forward and inward, is covered by the aponeurosis derived 
from the tendon of the Sartorius and by the tendons of the Gracilis and Semiten- 
dinosus, all of which are inserted nearly as far forward as the anterior border; in 
the rest of its extent it is subcutaneous. [All this surface, together with the crest 
and the internal malleolus, can be well studied on the living model. They are of 
great use in determining the question of fracture, periostitis, oedema, etc.] 
The external surface is narrower than the internal; its upper two-thirds pre- 
sent a shallow groove for the attachment of the Tibialis anticus muscle; its lower 
third is smooth, convex, curves gradually forward to the anterior part of the bone, 
and is covered from within outward by the tendons of the following muscles: Tibi- 
alis anticus, Extensor proprius pollicis, Extensor longus digitorum. 
The posterior surface (Fig. 230) presents at its upper part a prominent ridge, 
the oblique line of the tibia, which extends from the back part of the articular facet 
for the fibula obliquely downward to the internal border, at the junction of its upper 
and middle thirds. It marks the limit for the insertion of the Popliteus muscle, and 
serves for the attachment of the popliteal fascia and part of the Soleus, Flexor longus 
digitorum, and Tibialis posticus muscles; the triangular concave surface, above and 
to the inner side of this line, gives attachment to the Popliteus muscle. The middle 
third of the posterior surface is divided by a vertical ridge into two lateral halves: 
the ridge is well marked at its commencement at the oblique line, but becomes grad- 
ually indistinct below: the inner and broader half gives attachment to the Flexor 
longus digitorum, the outer and narrower to part of the Tibialis posticus. The 
remaining part of the bone presents a smooth surface covered by the Tibialis pos- 
ticus, Flexor longus digitorum, and Flexor longus pollicis muscles. Immediately 
below the oblique line is the medullary foramen, which is directed obliquely 
downward. 
The Lower Extremity, much smaller than the upper, presents five surfaces; it 
is prolonged downward, on its inner side, into a strong process, the internal malleo- 
lus. The inferior surface of the bone is quadrilateral, and smooth for articulation 
with the astragalus. This surface is concave from before backward, and broader in 
front than behind. It is traversed from before backward by a slight elevation sep- 
arating two lateral depressions. It is narrow internally, where the articular surface 
becomes continuous with that on the inner malleolus. The anterior surface of the 
lower extremity is smooth and rounded above, and covered by the tendons of the 
Extensor muscles of the toes; its lower margin presents a rough transverse depres- 
sion, for the attachment of the anterior ligament of the ankle-joint; the posterior THE FIBULA. 
281 
surface presents a superficial groove directed obliquely downward and inward, con- 
tinuous with a similar groove on the posterior extremity of the astragalus, and serv- 
ing for the passage of the tendon of the Flexor longus pollicis; the external surface 
presents a triangular rough depression for the attachment of the inferior interosseous 
ligament connecting it with the fibula; the lower part of this depression is smooth, 
covered with cartilage in the recent state, and articulates with the fibula. This 
surface is bounded by two prominent ridges, continuous above with the interosseous 
ridge; they afford attachment to the anterior and posterior tibio-fibular ligaments. 
The internal surface of the lower extremity is prolonged downward to form a strong 
pyramidal process, flattened from without inward-the inner malleolus. The inner 
surface of this process is convex and subcutaneous; its outer surface, smooth and 
slightly concave, deepens the articular surface for the astragalus; its anterior border 
is rough, for the attachment of the anterior fibres of the Deltoid ligament; its pos- 
terior border presents a broad and deep groove directed obliquely downward and 
inward, which is occasionally double; this groove transmits the tendons of the Tibi- 
alis posticus and Flexor longus digitorum 
muscles. The summit of the internal mal- 
leolus is marked by a rough depression 
behind, for the attachment of the internal 
lateral ligament of the ankle-joint. 
Structure.-Like that of the other 
long bones. At the junction of the mid- 
dle and lower third, where the bone is 
smallest, the wall of the shaft is thicker 
than in other parts, in order to compen- 
sate for the smallness of the calibre of 
the bone. 
Development.-By three centres (Fig. 
231): one for the shaft and one for each 
extremity. Ossification commences in the 
centre of the shaft about the seventh 
week, and gradually extends toward either 
extremity. The centre for the upper 
epiphysis appears at birth; it is flattened 
in form, and has a thin, tongue-shaped 
process in front, which forms the tubercle. 
That for the lower epiphysis appears in 
the second year. The lower epiphysis 
joins the shaft at about the eighteenth, 
and the upper one about the twentieth, 
year. Two additional centres occasionally 
exist-one for the tongue-shaped process 
of the upper epiphysis, the tubercle, and one for the inner malleolus. 
Articulations.-With three bones: the femur, fibula, and astragalus. 
Attachment of Muscles.-To twelve: to the inner tuberosity, the Semimem- 
branosus ; to the outer tuberosity, the Tibialis anticus and Extensor longus digito- 
rum and Biceps; to the shaft, its internal surface, the Sartorius, Gracilis, and 
Semitendinosus; to its external surface, the Tibialis anticus; to its posterior surface, 
the Popliteus, Soleus, Flexor longus digitorum, and Tibialis posticus; to the tuber- 
cle, the ligamentum patellae. 
Fig. 231. 
Appta.rs a t birth 
\J0i71s Shaft about 
1 yr 
Appears at 
Joins Shaft about 
iSftf v:r 
Plan of the Development of the Tibia, by three 
centres. 
The Fibula (Figs. 229, 230). 
The Fibula [fibula, a clasp) is situated at the outer side of the leg. It is the 
smaller of the two bones, and, in proportion to its length, the most slender of all 
the long bones; it is placed nearly parallel with the tibia. Its upper extremity is 
small, placed [toward the back of the head of the tibia, and] below the level of the 282 
THE SKELETON. 
knee-joint, and excluded from its formation; the lower extremity inclines a little 
forward, so as to be on a plane anterior to that of the upper end, projects below 
the tibia, and forms the outer angle. It presents for examination a shaft and 
two extremities. 
The Upper Extremity, or head, is of an irregular rounded form, presenting 
above a flattened articular facet directed upward and inward, for articulation with a 
corresponding facet on the external tuberosity of the tibia. [This extremity can 
always be felt in the model.] On the outer side is a thick and rough prominence, 
continued behind into a pointed eminence, the styloid process, which projects upward 
from the posterior part of the head. The prominence gives attachment to the tendon 
of the Biceps muscle and to the long external lateral ligament of the knee, the liga- 
ment dividing the tendon intoJtwo parts. The summit of the styloid process gives 
attachment to the short external lateral ligament. The remaining part of the cir- 
cumference of the head is rough, for the attachment of the anterior superior tibio- 
fibular ligament and the upper and anterior part of the Peroneus longus in front, 
and of the posterior superior tibio-fibular ligament and the upper fibres of the outer 
head of the Soleus muscle behind. 
The Lower Extremity, or external malleolus, is of a pyramidal form, some- 
what flattened from without inward, and is longer and descends lower than the 
internal malleolus. Its external surface is convex, subcutaneous, and continuous 
with the triangular (also subcutaneous) surface on the outer side of the shaft. The 
internal surface presents in front a smooth triangular facet, broader above than 
below and convex from above downward, which articulates with a corresponding 
surface on the outer side of the astragalus. Behind and beneath the articular sur- 
face is a rough depression, which gives attachment to the posterior fasciculus of the 
external lateral ligament of the ankle. The anterior border is thick and rough, and 
marked below by a depression, for the attachment of the anterior fasciculus of the 
external lateral ligament. The posterior border is broad and marked by a shallow 
groove, for the passage of the tendons of the Peroneus longus and brevis muscles. 
The summit is rounded, and gives attachment to the middle fasciculus of the exter- 
nal lateral ligament. 
The shaft presents four surfaces-anterior, posterior, internal, and external; and 
four borders-the antero-external, the antero-internal, the postero-external, and the 
postero-internal. 
The antero-external border commences above in front of the head, runs verti- 
cally downward to a little below the middle of the bone, and then, curving some- 
what outward, bifurcates so as to embrace the triangular subcutaneous surface 
immediately above the outer surface of the external malleolus. This border gives 
attachment to an intermuscular septum which separates the extensor muscles on 
the anterior surface of the leg from the Peroneus longus and brevis muscles. 
The antero-internal border, or interosseous ridg-e, is situated close to the 
inner side of the preceding, and runs nearly parallel with it in the upper third of 
its extent, but diverges from it so as to include a broader space in the lower two- 
thirds.. It commences above just beneath the head of the bone (sometimes it is 
quite indistinct for about an inch below the head), and terminates below at the 
apex of a rough triangular surface immediately above the articular facet of the 
external malleolus. It serves for the attachment of the interosseous membrane, 
and separates the extensor muscles in front from the flexor muscles behind. The 
portion of bone included between the anterior and interosseous lines forms the 
anterior surface. 
The postero-external border is sharp and prominent; it commences above at 
the base of the styloid process, and terminates below in the posterior border of the 
outer malleolus. It is directed outward above, backward in the middle of its 
course, backward and a little inward below, and gives attachment to an aponeur- 
osis which separates the peronei muscles on the outer surface of the shaft from the 
flexor muscles on its posterior surface. 
The postero-internal border, sometimes called the oblique line, commences THE FIBULA. 
283 
above at the inner side of the head, and terminates by becoming continuous with 
the antero-internal border or interosseous ridge at the lower fourth of the bone. 
It is well marked and prominent at the upper and middle parts of the bone, less 
marked below, where it terminates at the apex of the rough triangular surface 
immediately above the articular facet of the external malleolus. It gives attach- 
ment to an aponeurosis which separates the Tibialis posticus from the Soleus above 
and the Flexor longus pollicis below. 
The anterior surface is the interval between the antero-external and antero- 
internal borders. It is extremely narrow and flat in the upper third of its extent, 
broader and grooved longitudinally in its lower third ; it serves for the attachment 
of three muscles-the Extensor longus digitorum, Peroneus tertius, and Extensor 
proprius pollicis. 
The external surface is the space between the antero-external and postero- 
external borders. It is much broader than the preceding, and often deeply 
grooved, and is directed outward in the upper two-thirds of its course, backward 
in the lower third, where it is continuous with the posterior border of the external 
malleolus. This surface is completely occupied by the Peroneus longus and brevis 
muscles. 
The internal surface is the interval included between the antero-internal and 
the postero-internal borders. It is directed inward, and is grooved for the attach- 
ment of the Tibialis posticus muscle. 
The posterior surface is the space included between the postero-external and 
the postero-internal borders; it is continuous below with the rough triangular sur- 
face above the articular facet of the outer malleolus ; it is directed backward above, 
backward and inward at its middle, directly inward 
below. Its upper .third is rough, for the attach- 
ment of the Soleus muscle; its lower part presents 
a triangular rough surface connected to the tibia 
by a strong interosseous ligament, and between 
these two points the entire surface is covered by 
the fibres of origin of the Flexor longus pollicis 
muscle. At about the middle of this surface is 
the nutrient foramen, which is directed downward. 
In order to distinguish the side to which the 
bone belongs, hold it with the lower extremity 
downward, and the broad groove for the Peronei 
tendons backward-i. e. toward the holder: the 
triangular subcutaneous surface will then be di- 
rected to the side to which the bone belongs. 
Articulations.-With two bones: the tibia 
and astragalus. 
Development.-By three centres (Fig. 232): 
one for the shaft and one for each extremity. Os- 
sification commences in the shaft about the eighth 
week of foetal life, a little later than in the tibia, 
and extends gradually toward the extremities. At 
birth both ends are cartilaginous. Ossification 
commences in the lower end in the second year, 
and in the upper one about the fourth year. The 
lower epiphysis, the first in which ossification com- 
mences, becomes united to the shaft first, contrary 
to the law which appears to prevail with regard to 
the junction of epiphyses with diaphyses: this takes place about the twentieth 
year; the upper epiphysis is joined about the twenty-fifth year.1 
Attachment of Muscles.-To nine : to the head, the Biceps, Soleus, and Pero- 
Fig. 232. 
AppZt about ifUJyS-i 
-Unites about 2S&*iE. 
Approve at 2 
-Unites about 20&tfl 
Plan of the Development of the Fibula, 
by three centres. 
1 It will be observed that in the fibula, as in other long bones, the epiphysis toward which the 
nutrient artery is directed is the one first joined to the shaft. 284 
THE SKELETON. 
neus longus; to the shaft, its anterior surface, the Extensor longus digitorum, Pero- 
neus tertius, and Extensor proprius pollicis; to the internal surface, the Tibialis 
posticus; to the posterior surface, the Soleus and Flexor longus pollicis; to the 
external surface, the Peroneus longus and brevis. 
THE FOOT (Figs. 233, 234). 
The skeleton of the Foot consists of three divisions: the Tarsus, Metatarsus, 
and Phalanges. 
The Tarsus. 
The bones of the Tarsus are seven in number-viz. the calcaneum, or os calcis, 
astragalus, cuboid, scaphoid, internal, middle, and external cuneiform bones. 
The Calcaneum. 
The Calcaneum, or Os Calcis (calx, the heel), is the largest and strongest of 
the tarsal bones. It is irregularly cuboidal in form, and situated at the lower and 
back part of the foot, serving to transmit the weight of the body to the ground, 
and forming a strong lever for the muscles of the calf. It presents for examination 
six surfaces-superior, inferior, external, internal, anterior, and posterior. 
The superior surface is formed, behind, of the upper aspect of that part of the 
os calcis which projects backward to form the heel. It varies in length in different 
individuals; is convex from side to side, concave from before backward, and corre- 
sponds above to a mass of adipose substance placed in front of the tendo Achillis. 
In the middle of the superior surface are two (sometimes three) articular facets, sep- 
arated by a broad shallow groove which is directed obliquely forward and outward, 
and is rough for the attachment of the interosseous ligament connecting the astrag- 
alus and os calcis. Of the two articular surfaces, the external is the larger, and 
situated on the body of the bone: it is of an oblong form, wider behind than in 
front and convex from before backward. The internal articular surface is sup- 
ported on a projecting process of bone called the lesser process of the calcaneum 
(sustentaculum tali') ; it is also oblong, concave longitudinally, and sometimes sub- 
divided into two parts, which differ in size and shape. More anteriorly is seen the 
upper surface of the greater prrocess, marked by a rough depression, for the attach- 
ment of numerous ligaments and the origin of the Extensor brevis digitorum 
muscle. 
The inferior surface is narrow, rough, uneven, wider behind than in front, and 
convex from side to side; it is bounded posteriorly by two tubercles separated by 
a rough depression: the external, small, prominent, and rounded, gives attachment 
to part of the Abductor minimi digiti; the internal, broader and larger, for the 
support of the heel, gives attachment by its prominent inner margin to the Abduc- 
tor pollicis, and in front to the Flexor brevis digitorum muscles; the depression 
between the tubercles attaches the Abductor minimi digiti and plantar fascia. The 
rough surface in front of the tubercles gives attachment to the long plantar ligament 
and to the outer head of the Flexor accessorius muscle; and to a prominent tubercle 
nearer the anterior part of the bone, as well as to a transverse groove in front of it, 
is attached the short plantar ligament. 
The external surface is broad, flat, and almost subcutaneous; it presents near 
its centre a tubercle, for the attachment of the middle fasciculus of the external 
lateral ligament. Above the tubercle is a broad smooth surface giving attachment, 
at its upper and anterior part, to the external calcaneo-astragaloid ligament; and 
in front of the tubercle a narrow surface marked by two oblique grooves, separated 
by an elevated ridge which varies much in size in different bones: it is named the 
peroneal ridge or spine, and gives attachment to a prolongation from the external THE CALCANEUM. 
285 
Fig. 233. 
Q-roove for Tendon of 
FLEXOR LONGOS POLLiCIS 
Groove for peroneus loncus 
Groove for PERONEUS BREVIS 
Tarsus 
PERONEUS TERTIUS. 
PERONEUS BREVIS. \ 
Metatarsus 
Tnnervixist tendon of 
EXT.BREVIS PICITORUM 
TJaiLajiiges 
CXT. 10NCUS PCULIGIS 
Bones of the Right Foot, dorsal surface. 286 
THE SKELETON. 
Fig. 234. 
OUTER HEAD. OF ACCESS 
FLEXOR BMEVIS POLUDO 
TulercU of 
Scaphoid 
TfeiALIS ANTlCUs/ 
FLEXOR BREVI9 
& ABDUCTOR 
MINIMI DICITI 
FLEXOR BREVIS 
/ OIQITORUM 
FLEXOR LONGU3 
S' DICJTOaUM 
Bones of the Right Foot, plantar surface. THE CUBOID. 
287 
annular ligament. The superior groove transmits the tendon of the Peroneus 
brevis; the inferior, the tendon of the Peroneus longus. 
The internal surface presents a deep concavity directed obliquely downward 
and forward, for the transmission of the plantar vessels and nerves and Flexor 
tendons into the sole of the foot; it affords attachment to part of the Flexor acces- 
sorius muscle. This surface presents an eminence of bone, the lesser process or 
sustentaculum tali, which projects horizontally inward from its upper and fore 
part, and to which a slip of the tendon of the Tibialis posticus is attached. This 
process is concave above, and supports the anterior articular surface of the astrag- 
alus ; below it is grooved for the tendon of the Flexor longus pollicis. Its free 
margin is rough for the attachment of part of the internal lateral ligament of the 
ankle-joint. 
The anterior surface, of a somewhat triangular form, is smooth, concavo-con- 
vex, and articulates with the cuboid. It is surmounted on its outer side by a rough 
prominence which forms an important guide to the surgeon in the performance of 
Chopart's amputation. 
The posterior surface is rough, prominent, convex, and wider below than 
above. Its lower part is rough, for the attachment of the tendo Achillis and of 
the Plantaris muscle; its upper part is smooth, and is covered by a bursa which 
separates the tendon from the bone. 
[The calcaneum, in nearly all its extent, is accessible to touch, and can be 
grasped to fix it or move it, in the determination of suspected fractures or other 
injuries.] 
Articulations.-With two bones: the astragalus and cuboid. 
Attachment of Muscles.-To eight: part of the Tibialis posticus, the tendo 
Achillis, Plantaris, Abductor pollicis, Abductor minimi digiti, Flexor brevis digi- 
torum, Flexor accessorius, and Extensor brevis digitorum. 
The Cuboid (xo/9o<, a cube, and eZdoc, like) bone is placed on the outer side of 
the foot, in front of the os calcis, and behind the fourth and fifth metatarsal bones. 
It is of a pyramidal shape, its base being directed upward and inward, its apex 
downward and outward. It may be distinguished from the other tarsal bones by 
the existence of a deep groove on its under surface, for the tendon of the Peroneus 
longus muscle. It presents for examination six surfaces, three articular and three 
non-articular. 
The non-articular surfaces are the superior, inferior, and external. The supe- 
rior or dorsal surface, directed upward and outward, is rough, for the attachment 
of numerous ligaments. The inferior or plantar surface presents in front a deep 
groove, which runs obliquely from without, forward and inward; it lodges the ten- 
don of the Peroneus longus, and is bounded behind by a prominent ridge, to which 
is attached the long calcaneo-cuboid ligament. The ridge terminates externally in 
an eminence, the tuberosity of the cuboid, the surface of which presents a convex 
facet, for articulation with the sesamoid bone of the tendon contained in the groove. 
The surface of bone behind the groove is rough, for the attachment of the short 
plantar ligament and a few fibres of the Flexor brevis pollicis. The external sur- 
face, the smallest and narrowest of the three, presents a deep notch formed by the 
commencement of the peroneal groove. 
The articular surfaces are the posterior, anterior, and internal. The posterior 
surface is smooth, triangular, and concavo-convex, for articulation with the anterior 
surface of the os calcis. The anterior, of smaller size, but also irregularly trian- 
gular, is divided by a vertical ridge into two facets: the inner facet, quadrilateral 
in form, articulates with the fourth metatarsal bone; the outer one, larger and more 
triangular, articulates with the fifth metatarsal. The internal surface is broad, 
rough, irregularly quadrilateral, presenting at its middle and upper part a smooth 
ova] facet, for articulation with the external cuneiform bone; and behind this (occa- 
The Cuboid. 288 
THE SKELETON. 
sionally) a smaller facet, for articulation with the scaphoid; it is rough in the rest 
of its extent, for the attachment of strong interosseous ligaments. 
To ascertain to which foot it belongs, hold the bone so that its under surface, 
marked by the peroneal groove, looks downward, and the large concavo-convex 
articular surface backward toward the holder: the narrow non-articular surface, 
marked by the commencement of the peroneal groove, will point to the side to 
which the bone belongs. 
Articulations.-With four bones: the os calcis, external cuneiform, and the 
fourth and fifth metatarsal bones; occasionally with the scaphoid. 
Attachment of Muscles.-Part of the Flexor brevis pollicis. 
The Astragalus. 
The Astragalus (darpdyaAot;, a die) is the largest of the tarsal bones, next to 
the os calcis. It occupies the middle and upper part of the tarsus, supporting the 
tibia above, articulating with the malleoli on either side, resting below upon the os 
calcis, and joined in front to the scaphoid. This bone may easily be recognized by 
its large rounded head, by the broad articular facet on its upper convex surface, or 
by the two articular facets separated by a deep groove on its under concave surface. 
It presents six surfaces for examination. 
The superior surface presents, behind, a broad smooth trochlear surface, for 
articulation with the tibia. The trochlea is broader in front than behind, convex 
from before backward, slightly concave from side to side; in front of it is the upper 
surface of the neck of the astragalus, rough for the attachment of ligaments. The 
inferior surface presents two articular facets separated by a deep groove. The 
groove runs obliquely forward and outward, becoming gradually broader and deeper 
in front; it corresponds with a similar groove upon the upper surface of the os 
calcis, and forms, when articulated with that bone, a canal filled up in the recent 
state by the interosseous calcaneo-astragaloid ligament. Of the two articular facets, 
the posterior is the larger, of an oblong form and deeply concave from side to side; 
the anterior, although nearly of equal length, is narrower, of an elongated oval 
form, convex longitudinally, and often subdivided into two by an elevated ridge; 
of these, the posterior articulates with the lesser process of the os calcis; the ante- 
rior, with the upper surface of the calcaneo-scaphoid ligament. The internal surface 
presents at its upper part a pear-shaped articular facet for the inner malleolus, con- 
tinuous above with the trochlear surface; below the articular surface is a rough 
depression, for the attachment of the deep portion of the internal lateral ligament. 
The external surface presents a large triangular facet, concave from above down- 
ward, for articulation with the external malleolus; it is continuous above with the 
trochlear surface; and in front of it is a rough depression, for the attachment of 
the anterior fasciculus of the external lateral ligament of the ankle-joint. The 
anterior surface, convex and rounded, forms the head of the astragalus; it is smooth, 
of an oval form, and directed obliquely inward and downward; it articulates with 
the scaphoid. On its under surface is a' small facet, continuous in front with the 
articular surface of the head; behind with the smaller facet, for the os calcis. This 
rests on the inferior calcaneo-scaphoid ligament, being separated from it by a pro- 
longation of the synovial sac of the astragalo-scaphoid joint. The head is sur- 
rounded by a constricted portion, the neck of the astragalus. The posterior sur- 
face is narrow, and traversed by a groove which runs obliquely downward and 
inward, and transmits the tendon of the Flexor longus pollicis, external to which 
is a horizontal notch or depression in which the posterior fasciculus of the external 
lateral ligament is lodged. 
[Much of this bone, especially its trochlear surface and edges and the head, 
can be excellently studied in the living model, especially if the foot be ex- 
tended.] 
To ascertain to which foot it belongs, hold the bone with the broad articular 
surface upward and the rounded head forward; the lateral triangular articular THE SCAPHOID. 
289 
surface for the external malleolus will then point to the side to which the bone 
belongs. 
Articulations.-With four bones: tibia, fibula, os calcis, and scaphoid. 
The Scaphoid. 
The Scaphoid or Navicular Bone, so called from its fancied resemblance to a 
boat (axaiprj, a boat), is situated at the inner side of the tarsus, between the astrag- 
alus behind and the three cuneiform bones in front. This bone may be distin- 
guished by its form, being concave behind, convex and subdivided into three facets 
in front. 
The anterior surface, of an oblong form, is convex from side to side, and sub- 
divided by two ridges into three facets, for articulation with the three cuneiform 
bones. The posterior surface is oval, concave, broader externally than internally, 
and articulates with the rounded head of the astragalus. The superior surface is 
convex from side to side, and rough, for the attachment of ligaments. The inferior 
is somewhat concave, irregular, and also rough, for the attachment of ligaments. 
The internal surface presents a rounded tubercular eminence, the tuberosity of the 
scaphoid, which gives attachment to part of the tendon of the Tibialis posticus. 
[This can always be felt, and is one of the important landmarks of the foot.] 
The external surface is rough, and irregular, for the attachment of ligamentous 
fibres, and occasionally presents a small facet for articulation with the cuboid 
bone. 
To ascertain to which foot it belongs, hold the bone with the concave articular 
surface backward and the convex dorsal surface upward; the external surface will 
point to the side to which the bone belongs. 
Articulations.-With four bones : astragalus and three cuneiform ; occasionally 
also with the cuboid. 
Attachment of Muscles.-Part of the Tibialis posticus. 
The Cuneiform Bones have received their name from their wedge-like shape 
(cuneus, a wedge, and/onna, likeness). They form with the cuboid the most ante- 
rior row of the tarsus, being placed between the scaphoid behind, the three inner- 
most metatarsal bones in front, and the cuboid externally. They are called the 
first, second, and third, counting from the inner to the outer side of the foot, and, 
from their position, internal, middle, and external. 
The Internal Cuneiform. 
The Internal Cuneiform is the largest of the three. It is situated at the inner 
side of the foot, between the scaphoid behind and the base of the first metatarsal 
in front. It may be distinguished from the other two by its large size and its more 
irregular wedge-like form. Without the others it may be known by the large kid- 
ney-shaped anterior articulating surface, and by the prominence on the inferior or 
plantar surface for the attachment of the Tibialis posticus. It presents for exam- 
ination six surfaces. 
The internal surface is subcutaneous, and forms part of the inner border of the 
foot; it is broad, quadrilateral, and presents at its anterior inferior angle a smooth 
oval facet into which the tendon of the Tibialis anticus is partially inserted; in the 
rest of its extent it is rough, for the attachment of ligaments. The external surface 
is concave, presenting along its superior and posterior borders a narrow L-shaped 
surface for articulation with the middle cuneiform behind and second metatarsal 
bone in front: in the rest of its extent it is rough for the attachment of ligaments, 
and prominent below, where it forms part of the tuberosity. The anterior surface, 
kidney-shaped, much larger than the posterior, articulates with the metatarsal bone 
of the great toe. The posterior surface is triangular, concave, and articulates with 
the innermost and largest of the three facets on the anterior surface of the scaphoid. 
The inferior or plantar surface is rough, and presents a prominent tuberosity at its 290 
THE SKELETON. 
back part for the attachment of part,of the tendon of the Tibialis posticus. It 
also gives attachment in front to part of the tendon of the Tibialis anticus. The 
superior surface is the narrow pointed end of the wedge, which is directed upward 
and outward; it is rough, for the attachment of ligaments. 
To ascertain to which side it belongs, hold the bone so that its superior narrow 
edge looks upward and the long, kidney-shaped articular surface forward; the 
external surface, marked by its vertical and horizontal articular facets, will point 
to the side to which it belongs. 
Articulations.-With four bones: scaphoid, middle cuneiform, first and second 
metatarsal bones. 
Attachment of Muscles.-To two: the Tibialis anticus and posticus. 
The Middle Cuneiform. 
The Middle Cuneiform, the smallest of the three, is of very regular wedge-like 
form, the broad extremity being placed upward, the narrow end downward. It is 
situated between the other two bones of the same name, and articulates with the 
scaphoid behind and the second metatarsal in front. It may be distinguished from 
the external cuneiform bone, which it much resembles in general appearance, by 
the articular facet, of angular form, which runs round the upper and back part of 
its inner surface; and, if the two bones from the same foot are together, the middle 
cuneiform is much the smaller. 
The anterior surface, triangular in form and narrower than the posterior, articu- 
lates with the base of the second metatarsal bone. The posterior surface, also tri- 
angular, articulates with the scaphoid. The internal surface presents an L-shaped 
articular facet running along the superior and posterior borders, for articulation with 
the internal cuneiform, and is rough in the rest of its extent, for the attachment of 
ligaments. The external surface presents posteriorly a smooth facet, for articula- 
tion with the external cuneiform bone. The superior surface forms the base of the 
wedge; it is quadrilateral, broader behind than in front, and rough, for the attach- 
ment of ligaments. The inferior surface, pointed and tubercular, is also rough, for 
ligamentous attachment. 
To ascertain to which foot the bone belongs, hold-its superior or dorsal surface 
upward, the broadest edge being toward the holder : the smooth facet (limited to the 
posterior border) will then point to the side to which it belongs. 
Articulations.-With four bones: scaphoid, internal and external cuneiform, 
and second metatarsal bone. 
Attachment of Muscle.-A slip from the tendon of the Tibialis posticus is 
attached to this bone. 
The External Cuneiform. 
The External Cuneiform, intermediate in size between the two preceding, is 
of a very regular wedge-like form, the broad extremity being placed upward, the 
narrow end downward. It occupies the centre of the front row of the tarsus, between 
the middle cuneiform internally, the cuboid externally, the scaphoid behind, and the 
third metatarsal in front. It is distinguished from the internal cuneiform bone by 
its more regular wedge-like shape, and by the absence of the kidney-shaped articu- 
lar surface: from the middle cuneiform, by the absence of the L-shaped facet and by 
the two articular facets which are present on both its inner and outer surfaces. It 
has six surfaces for examination. 
The anterior surface, triangular in form, articulates with the third metatarsal 
bone. The posterior surface articulates with the most external facet of the scaphoid, 
and is rough below, for the attachment of ligamentous fibres. The internal surface 
presents two articular facets, separated by a rough depression: the anterior one, 
situated at the superior angle of the bone, articulates with the outer side of the 
base of the second metatarsal bone; the posterior one skirts the posterior border, THE METATARSAL BONES. 
291 
and articulates with the middle cuneiform; the rough depression between the two 
gives attachment to an interosseous ligament. The external surface also presents 
two articular facets, separated by a rough non-articular surface; the anterior facet, 
situated at the superior angle of the bone, is small, and articulates with the inner 
side of the base of the fourth metatarsal; the posterior and larger one articulates 
with the cuboid; the rough non-articular surface serves for the attachment of an 
interosseous ligament. The three facets for articulation with the three metatarsal 
bones are continuous with one another, and covered by a prolongation of the same 
cartilage; the facets for articulation with the middle cuneiform and scaphoid are 
also continuous, but that for articulation with the' cuboid is usually separate. The 
superior or dorsal surface is of an oblong square form, its posterior external angle 
being prolonged backward. The inferior or plantar surface is an obtuse rounded 
margin, and serves for the attachment of part of the tendon of the Tibialis posticus, 
part of the Flexor brevis pollicis, and ligaments. 
To ascertain to which side it belongs, hold the bone with the broad dorsal sur- 
face upward, the prolonged edge backward; the separate articular facet for the 
cuboid will point to the proper side. 
Articulations.-With six bones: the scaphoid, middle cuneiform, cuboid, and 
second, third, and fourth metatarsal bones. 
Attachment of Muscles.-To two: part of the Tibialis posticus and Flexor 
brevis pollicis. 
The Metatarsal Bones. 
The Metatarsal Bones are five in number ; they are long hones, and subdivided 
into a shaft and two extremities. 
Common Characters.-The shaft is prismoid in form, tapers gradually from 
the tarsal to the phalangeal extremity, and is slightly curved longitudinally, so as 
to be concave below, slightly convex above. The posterior extremity, or base, is 
wedge-shaped, articulating by its terminal surface with the tarsal bones and by its 
lateral surfaces with the contiguous metatarsal bones, its dorsal and plantar surfaces 
being rough, for the attachment of ligaments. The anterior extremity, or head, 
presents a terminal rounded articular surface, oblong from above downward, and 
extending farther backward below than above. Its sides are flattened, and present 
a depression, surmounted by a tubercle, for ligamentous attachment. Its under sur- 
face is grooved in the middle line for the passage of the Flexor tendon, and marked 
on each side by an articular eminence continuous with the terminal articular surface. 
Peculiar Character.-The First is remarkable for its great size, but is the 
shortest of all the metatarsal bones. The shaft is strong, and of well-marked pris- 
moid form. The posterior extremity presents no lateral articular facets ; its terminal 
articular surface is of large size, kidney-shaped, and its circumference grooved, for 
the tarso-metatarsal ligaments ; its inferior angle presents a rough oval prominence, 
for the insertion of the tendon of the Peroneus longus. The head is of large size; 
on its plantar surface are two grooved facets, over which glide sesamoid bones; the 
facets are separated by a smooth elevated ridge. 
This bone is known by the single kidney-shaped articular surface on its base, 
the deeply grooved appearance of the plantar surface of its head, and its great thick- 
ness relatively to its length. When it is placed in its natural position the concave 
border of the kidney-shaped articular surface on its base points to the side to which 
the bone belongs. 
The Second is the longest and largest' of the remaining metatarsal bones, being 
prolonged backward into the recess formed between the three cuneiform bones. Its 
tarsal extremity is broad above, narrow and rough below. It presents four articu- 
lar surfaces : one behind, of a triangular form, for articulation with the middle cunei- 
form ; one at the upper part of its internal lateral surface, for the articulation with 
the internal cuneiform; and two on its external lateral surface, a superior and an 
inferior, separated by a rough depression. Each of the latter articular surfaces is 
divided by a vertical ridge into two parts; the anterior segment of each facet articu- 292 
THE SKELETON. 
lates with the third metatarsal, the two posterior (sometimes continuous) with the 
external cuneiform. * 
The facets on the tarsal extremity of the second metatarsal bone serve at once 
to distinguish it from the rest and to indicate the foot to which it belongs, there 
being one facet at the upper angle of the internal surface, and two facets, each sub- 
divided into two parts, on the external surface, pointing to the side to which the 
bone belongs. The fact that the two posterior subdivisions of these external facets 
sometimes run into one should not be forgotten. 
The Third articulates behind, by means of a triangular smooth surface, with the 
external cuneiform; on its inner side, by two facets, with the second metatarsal; 
and on its outer side, by a single facet, with the fourth metatarsal. The latter facet 
is of circular form and situated at the upper angle of the base. 
The third metatarsal is known by its having at its tarsal end two undivided facets 
on the inner side and a single facet on the outer. This distinguishes it from the 
second metatarsal, in which the two facets found on one side of its tarsal end are 
each subdivided into two. The single facet (when the bone is put in its natural 
position) is on the side to which the bone belongs. 
The Fourth is smaller in size than the preceding; its tarsal extremity presents 
a terminal quadrilateral surface for articulation with the cuboid; a smooth facet on 
the inner side, divided by a ridge into an anterior portion for articulation with the 
third metatarsal, and a posterior portion for articulation with the external cunei- 
form ; on the outer side a single facet, for articulation with the fifth metatarsal. 
The fourth metatarsal is known by its having a single facet on either side of the 
tarsal extremity, that on the inner side being divided into two parts. If this sub- 
division be not recognizable, the fact that its tarsal end is bent somewhat outward 
will indicate the side to which it belongs, as Mr. Holden points out. 
The Fifth is recognized by the tubercular eminence on the outer side of its base. 
[This can always be felt, and is an important landmark in the foot.] It articulates 
behind, by a triangular surface cut obliquely from without inward, with the cuboid; 
and internally with the fourth metatarsal. 
The projection on the outer side of this bone at its tarsal end at once distin- 
guishes it from the others and points to the side to which it belongs. 
Articulations.-Each bone articulates with the tarsal bones by one extremity, 
and by the other with the first row of phalanges. The number of tarsal bones with 
which each metatarsal articulates is one for the first, three for the second, one for the 
third, two for the fourth, and one for the fifth. 
Attachment of Muscles.-To the first metatarsal bone, three: part of the 
Tibialis anticus, the Peroneus longus, and first Dorsal interosseous. To the second, 
four: the Adductor pollicis and first and second Dorsal interosseous, and a slip 
from the tendon of the Tibialis posticus. To the third, five: the Adductor pollicis, 
second and third Dorsal, and first Plantar interosseous, and a slip from the tendon 
of the Tibialis posticus. To the fourth, five: the Adductor pollicis, third and 
fourth Dorsal, and second Plantar interosseous, and a slip from the tendon of the 
Tibialis posticus. To the fifth, six : the Peroneus brevis, Peroneus tertius, Flexor 
brevis minimi digiti, Transversus pedis, fourth Dorsal, and third Plantar interosseous. 
Phalanges. 
The Phalang-es of the foot, both in number and general arrangement, resem- 
ble those in the hand, there being two in the great toe and three in each of the 
other toes. 
The phalanges of the first row resemble closely those of the hand. The shaft 
is compressed from side to side, convex above, concave below. The posterior extrem- 
ity is concave, and the anterior extremity presents a trochlear surface, for articulation 
with the second phalanges. 
The phalanges of the second row are remarkably small and short, but rathei 
broader than those of the first row. PHALANGES. 
293 
The ungual phalanges in form resemble those of the fingers, but they are smaller, 
flattened from above downward, presenting a broad base for articulation with the 
second row, and an expanded extremity for the support of the nail and end of 
the toe. 
Articulation.-The first row, with the metatarsal bones and second phalanges; 
the second of the great toe, with the first phalanx; and of the other toes, with the 
first and third phalanges; the third, with the second row. 
Attachment of Muscles.-To the first phalanges: Great toe, five muscles: 
innermost tendon of Extensor brevis digitorum, Abductor pollicis, Adductor pol- 
licis, Flexor brevis pollicis, Transversus pedis. Second toe, three muscles: first 
and second Dorsal interosseous and first Lumbrical. Third toe, three muscles: 
third Dorsal and first Plantar interosseous, and second Lumbrical. Fourth toe, 
three muscles: fourth Dorsal and second Plantar interosseous, and third Lumbrical. 
Fifth toe, four muscles: Flexor brevis minimi digiti, Abductor minimi digiti, and 
third Plantar interosseous, and fourth Lumbrical.-Second phalanges: Great toe: 
Extensor longus pollicis, Flexor longus pollicis. Other toes : Flexor brevis digito- 
rum, one slip of the common tendon of the Extensor longus and brevis digito- 
rum.1-Third phalanges: two slips from the common tendon of the Extensor longus 
and Extensor brevis digitorum, and the Flexor longus digitorum. 
The foot is constructed on the same principles as the hand, but modified to form 
a firm basis of support for the rest of the body when in the erect position. It is 
more solidly constructed, and its component parts are less movable on each other 
than in the hand. This is especially the case with the great toe, which has to assist 
in supporting the body and is therefore constructed with greater solidity; it lies 
parallel with the other toes, and has a very limited degree of mobility. On the 
contrary, the thumb, which is occupied in numerous and varied movements, is con- 
structed in such a manner as to permit of great mobility: its metacarpal bone is 
directed away from the others, so as to form an acute angle with the second, and it 
enjoys a considerable range of motion at its articulation with the carpus. The foot 
is placed at right angles to the leg-a position which is almost peculiar to man, and 
has relation to the erect position which he maintains. In order to allow of its sup- 
porting the weight of the whole body in this position with the least expenditure of 
material, it is constructed in the form of an arch. This arch is not, however, made 
up of two equal limbs. The hinder one, which is made up of the os calcis and the pos- 
terior part of the astragalus, is about half the length of the anterior limb, and meas- 
ures about three inches. The anterior limb consists of the rest of the tarsal and the 
metatarsal bones, and measures about six inches. It may be said to consist of two 
parts-an inner segment, made up of the head of the astragalus, the scaphoid, the 
three cuneiform, and the three inner metatarsal bones; and an outer segment, com- 
posed of the cuboid and the two outer metatarsal bones. The summit of the arch 
is at the superior articular surface of the astragalus and its two extremities; that is 
to say, the two points on which the arch rests in standing are the tubercles on the 
under surface of the os calcis posteriorly and the heads of the metatarsal bones 
anteriorly. The weakest part of the arch is the joint between the astragalus and 
scaphoid; and here it is more liable to yield in those who are overweighted and in 
those in whom the ligaments which complete and preserve the arch are relaxed. 
This weak point in the arch is braced on its concave surface by the inferior calca- 
neo-scaphoid ligament, which is said to be more elastic than most other ligaments, 
and thus allows the arch to yield from jars or shocks applied to the anterior portion 
of the foot, and quickly restores it to its pristine condition. This ligament is sup- 
ported on its under surface by the tendon of the Tibialis posticus muscle, which is 
spread out into a fan-shaped insertion, and prevents undue tension of the ligament 
or such an amount of stretching as would permanently elongate it. 
In addition to this longitudinal arch, the foot is said to present a transverse arch 
at the anterior part of the tarsus and hinder part of the metatarsus. This, how- 
1 Except the second phalanx of the fifth toe, which receives no slip from the Extensor brevis 
digitornm. 294 
THE SKELETON. 
ever, can scarcely be described as a true arch, but presents more the character of a 
half-dome [or half arch. This is especially supported by the tendon of the Pero- 
neus longus, running from the outer edge of the sole to its inner border at the base 
of the first metatarsal, and by the Transversus pedis]. The inner border of the 
central portion of the longitudinal arch is elevated from the ground, and from this 
point the bones arch over to the outer border, which is in contact with the ground, 
and, assisted by the longitudinal arch, produce a sort of rounded niche on the innei' 
side of the foot, which gives the appearance of a transverse as well as a longitu- 
dinal arch. 
The arch of the foot, from the point of the heel to the toes, is not quite straight, 
but is directed a little outward, so that the inner border is a little convex and the 
outer border concave. This disposition of the bones becomes more marked when 
the longitudinal arch of the foot is lost, as in the disease known under the name of 
" flat-foot." 
[The imprint of the foot-sole is a matter of great interest. If the sole be wetted, 
and placed for a moment on the bare floor, the normally-arched foot shows a broad 
imprint at the heel and at the ball of the toes, the two being connected on the outer 
edge of the sole by a band which is narrower or wider as the arch is more or less 
marked. In very arched feet the two may be entirely disconnected, while in the 
flat foot the imprint is continuous, the narrow band widening to the full width of 
the sole, its inner edge being a straight line instead of a marked curve. (See the 
Medical News, Aug. 12, 1882.)] 
Development of the Foot (Fig. 235). 
The Tarsal bones are each developed by a single centre, excepting the os calcis, 
which has an epiphysis for its posterior extremity. The centres make their appear- 
ance in the following order: os calcis at the sixth month of foetal life; astragalus, 
about the seventh month ; cuboid, at the ninth month ; external cuneiform, during 
the first year; internal cuneiform, in the third year; middle cuneiform and scaphoid, 
in the fourth year. The epiphysis for tire posterior tuberosity of the os calcis appears 
at the tenth year, and unites with the rest of the bone soon after puberty. 
The Metatarsal bones are each developed by two centres-one for the shaft and 
one for the digital extremity in the four outer metatarsal; one for the shaft and 
one for the base in the metatarsal bone of the great toe.1 Ossification commences in 
the centre of the shaft about the seventh week, and extends toward either extremity, 
and in the digital epiphyses about the third year; they become joined between the 
eighteenth and twentieth years. 
The Phalanges are developed by two centres for each bone: one for the shaft 
and one for the metatarsal extremity. 
Sesamoid Bones. 
These are small rounded masses, cartilaginous in early life, osseous in the adult, 
which are developed in those tendons which exert a great amount of pressure upon 
the parts over which they glide. It is said that they are more commonly found in 
the male than in the female, and in persons of an active muscular habit than in 
those who are weak and debilitated. They are invested throughout their whole 
surface by the fibrous tissue of the tendon in which they are found, excepting upon 
that side which lies in contact with the part over which they play, where they pre- 
sent a free articular facet. They may be divided into two kinds-those which glide 
over the articular surfaces of joints, and those which play over the cartilaginous 
facets found on the surfaces of certain bones. 
The sesamoid bones of the joints are-in the lower extremity, the patella, which 
is developed in the tendon of the Quadriceps extensor; two small sesamoid bones, 
1 As was noted in the first metacarpal bone, so in the first metatarsal, there is often to be observed 
a tendency to the formation of a second epiphysis in the distal extremity. (See foot-note, p. 259.) SESAMOID BONES. 
295 
found in the tendons of the Flexor brevis pollicis, opposite the metatarso- 
phalangeal joint of the great toe, and occasionally one in the metatarso-phalangeal 
joint of the second toe, the little toe, and, still more rarely, the third and fourth 
toes. 
In the upper extremity there are two on the palmar surface of the metacarpo- 
phalangeal joint in the thumb, developed in the tendons of the Flexor brevis 
Fig. 235. 
-App.f 10* yt 
unites after puberty 
Tarsus 
1 Centre for each lone 
except Os Calc is 
Metatarsus 
2 Centres for each bone 
/ for Shaft 
1 for Digital Extremity 
except I.*? 
Appears 5^1 y-t 
Unite 18-2.0*!' y.T 
Ayp. 
Vnite 18-20 y.T 
Apy?- 
yx 
Unite //-Afy' 
Phalanges 
ZCentresfor earJi hone 
J for Shaft 
{ for Metatarsal Ext .1 
Ay>p. 2.~If.mOr- 
AW. 
Unite /7-/S y?[ 
Ayy. mite- 
AypAOi yX 
Unite UJ-ISyT.f 
Jit1 i 
Plan of the Development of the Foot. 
pollicis, occasionally one or two opposite the metacarpo-phalangeal articulations of 
the fore and little fingers, and, still more rarely, one opposite the same j oints of the 
third and fourth fingers. 
Those found in the tendons which glide over certain bones occupy the following 
situations: one in the tendon of the Peroneus longus, where it glides through the 
groove in the cuboid bone; one appears late in life in the tendon of the Tibialis 
anticus, opposite the smooth facet on the internal cuneiform bone; one is found in 
the tendon of the Tibialis posticus, opposite the inner side of the astragalus; one 
in the outer head of the Gastrocnemius, behind the outer condyle of the femur; 
and one in the Psoas and Iliacus, where they glide over the body of the pubes. 
Sesamoid bones are found occasionally in the tendon of the Biceps, opposite the 
tuberosity of the radius; in the tendon of the Gluteus maximus, as it passes over 
the great trochanter; and in the tendons which wind round the inner and outer 
malleoli. The Articulations. 
THE various bones of which the Skeleton consists are connected together at 
different parts of their surfaces, and such a connection is designated by the 
name of Joint or Articulation. If the joint is immovable, as between the cranial 
and most of the facial bones, their adjacent margins are applied in almost close 
contact, a thin layer of fibrous membrane, the sutural ligament, and, at the base 
of the skull, in certain situations, a thin layer of cartilage, being interposed. 
Where slight movement is required, combined with great strength, the osseous 
surfaces are united by tough and elastic fibro-cartilages, as in the joints of the 
spine, the sacro-iliac and interpubic articulations; but in the movable joints the 
bones forming the articulation are generally expanded for greater convenience of 
mutual connection, covered by cartilage, held together by strong bands or capsules 
of fibrous tissue called ligaments, and partially lined by a membrane, the synovial 
membrane, which secretes a fluid to lubricate the various parts of which the joint 
is formed ; so that the structures which enter into the formation of a joint are bone, 
cartilage, fibro-cartilage, ligament, and synovial membrane. 
Bone constitutes the fundamental element of all the joints. In the long bones 
the extremities are the parts which form the articulations; they are generally some- 
what enlarged, consisting of spongy cancellous tissue with a thin coating of compact 
substance. In the flat bones the articulations usually take place at the edges, and 
in the short bones at various parts of their surface. The layer of compact bone 
which forms the articular surface, and to which the cartilage is attached, is called 
the articular lamella. It is of a white color, extremely dense, and varies in thick- 
ness. Its structure differs from ordinary bone-tissue in this respect, that it contains 
no Haversian canals and its lacunae are much larger than in ordinary bone and have 
no canaliculi. The vessels of the cancellous tissue as they approach the articular 
lamella turn back in loops, and do not perforate it; this layer is consequently more 
dense and firmer than ordinary bone, and is evidently designed to form a firm and 
unyielding support for the articular cartilage. 
The cartilage, which covers the articular surfaces of bone, and is therefore 
called articular, and also the varieties of fibro-cartilage, will be found described 
in the section on General Anatomy (p. 50). 
Ligaments are found in nearly all the movable articulations; they consist of 
bands of various forms, serving to connect together the articular extremities of 
bones, and composed mainly of bundles of white fibrous tissue placed parallel with, 
or closely interlaced with, one another, and presenting a white, shining silvery 
aspect. A ligament is pliant and flexible, so as to allow of the most perfect free- 
dom of movement, but strong, tough, and inextensile, so as not readily to yield 
under the most severely applied force; it is consequently well adapted to serve as 
the connecting medium between the bones. Some ligaments consist entirely of 
yellow elastic tissue, as the ligamenta subflava, which connect together the adjacent 
arches of the vertebrae, and the ligamentum nuchse in the lower animals. In these 
cases it will be observed that the elasticity of the ligament is intended to act as a 
substitute for muscular power. 
Synovial Membrane is a thin, delicate membrane, arranged in its simplest form 
like a short wide tube, attached by its open ends to the margins of the articular 
cartilages, and covering the inner surface of the various ligaments which connect 
the articulating surfaces, so that, along with the cartilages, it completely encloses 
the joint-cavity. Its secretion is thick, viscid, and glairy, like the white of egg, 
296 CLASSIFICATION OF JOINTS. 
297 
and is hence termed synovia. The synovial membranes found in the body aomit of 
subdivision into three kinds-articular, bursal, and vaginal. 
The articular synovial membranes are found in all the freely movable joints. 
In the foetus this membrane is said by Toynbee to be continued over the surface of 
the cartilages; but in the adult it is wanting, excepting at their circumference, upon 
which it encroaches foi' a short distance and to which it is firmly attached; it then 
invests the inner surface of the capsular or other ligaments enclosing the joint, and 
is reflected over the surface of any tendons passing through its cavity, as the tendon 
of the Popliteus in the knee and the tendon of the Biceps in the shoulder. In 
several of the joints the synovial membrane is thrown into folds which pass across 
the cavity. They are called synovial ligaments, and are especially distinct in the 
knee. Others are flattened folds, subdivided at their margins into fringe-like pro- 
cesses, the vessels of which have a convoluted arrangement. The latter generally 
project from the synovial membrane near the margin of the cartilage, and lie flat 
upon its surface. They consist of connective tissue covered with epithelium, and 
contain fat-cells in variable quantities, and, more rarely, isolated' cartilage-cells. 
The larger folds often contain considerable quantities of fat. They are found in 
most of the bursal and vaginal, as well as in the articular, synovial membranes, and 
were described by Clopton Havers as mucilaginous glands and as the source of the 
synovial secretion. Under certain diseased conditions similar processes are found 
covering the entire surface of the synovial membrane, forming a mass of peduncu- 
lated fibro-fatty growths which project into the joint. 
The bursce are found interposed between surfaces which move upon each other; 
producing friction, as in the gliding of a tendon or of the integument over pro- 
jecting bony surfaces. They admit of subdivision into two kinds-the bursa; 
mucosce and the synovial bursce. The former are large, simple, or irregular cavities 
in the subcutaneous areolar tissue, enclosing a clear viscid fluid. They are found 
in various situations, as between the integument and the front of the patella, over 
the olecranon, the malleoli, and other prominent parts. The synovial bursce are 
found interposed between muscles or tendons as they play over projecting bony sur- 
faces, as between the Glutei muscles and the surface of the great trochanter. They 
consist of a thin wall of connective issue partially covered by epithelium, and con- 
tain a viscid fluid. Where one of these exists in the neighborhood of a joint, it 
usually communicates with its cavity, as is generally the case with the bursa between 
the tendon of the Psoas and Iliacus and the capsular ligament of the hip, or the 
one interposed between the under surface of the Subscapularis and the neck of the 
scapula. 
The vaginal synovial membranes (synovial sheaths') serve to facilitate the glid- 
ing of tendons in the osseo-fibrous canals through which they pass. The membrane 
is here arranged in the form of a sheath, one layer of which adheres to the wall of 
the canal, and the other is reflected upon the outer surface of the contained tendon, 
the space between the two free surfaces of the membrane being partially filled with 
synovia. These sheaths are chiefly found surrounding the tendons of the flexor and 
extensor muscles of the fingers and toes as they pass through the osseo-fibrous canals 
in the hand or foot. 
Synovia is a transparent, yellowish-white or slightly reddish fluid, viscid like the 
white of egg, having an alkaline reaction and slightly saline taste. It consists, 
according to Frerichs, in the ox, of 94.85 water, 0.56 mucus and epithelium, 0.07 
fat, 3.51 albumen and extractive matter, and 0.99 salts. 
The articulations are divided into three classes: Synarthrosis, or immovable; 
Amphiarthrosis, or mixed; and Diarthrosis, or movable joints. 
1. Synarthrosis-Immovable Articulations. 
Synarthrosis includes all those articulations in which the surfaces of the bones 
are in almost direct contact, and in which there is no appreciable motion [as, for 
instance, the immovable "joint" between the blade and handle of a table-knife], 298 
ARTICULATIONS. 
as the joints between the bones of the cranium and face, excepting those of the 
lower jaw. The varieties of synarthrosis are three in number: Sutura, Schindy- 
lesis, and Gomphosis. 
Sutura (a seam).-Where the articulating surfaces are connected by a series of 
processes and indentations interlocked together, it is termed sutura vera, of which 
there are three varieties-sutura dentata, serrata, and limbosa. The surfaces of the 
bones are not in direct contact, being separated by a layer of membrane continuous 
externally with the pericranium, internally with the dura mater. The sutura den- 
tata (dens, a tooth) is so called from the tooth-like form of the projecting articular 
processes, as in the suture between the parietal bones. In the sutura serrata (serra, 
a saw) the edges of the two bones forming the articulation are serrated like the teeth 
of a fine saw, as between the two portions of the frontal bone. In the sutura lim- 
bosa (limbus, a selvage), besides the dentated processes there is a certain degree of 
bevelling of the articular surfaces, so that the bones overlap one another, as in the 
suture between the parietal and frontal bones. When the articulation is formed by 
roughened surfaces placed in apposition with one another, it is termed the false 
suture, sutura notha, of which there are two kinds-the sutura squamosa (squama, 
a scale), formed by the overlapping of two contiguous bones by broad bevelled mar- 
gins, as in the temporo-parietal (squamous) suture; and the sutura harmonia (dpp.o- 
via, a joining together), where there is simple apposition of two contiguous rough 
bony surfaces, as in the articulation between the two superior maxillary bones or of 
the horizontal plates of the palate bones. 
Schindylesis (ayivoblquu;, a fissure) is that form of articulation in which a thin 
plate of bone is received into a cleft or fissure formed by the separation of two 
laminae of another, as in the articulation of the rostrum of the sphenoid and per- 
pendicular plate of the ethmoid with the vomer, or in the reception of the latter in 
the fissure between the superior maxillary and palate bones. 
Gomphosis (ybfjupoc;, a nail) is an articulation formed by the insertion of a conical 
process into a socket, as a nail is driven into a board; this is not illustrated by any 
articulations between bones properly so called, but is seen in the articulation of the 
teeth with the alveoli of the maxillary bones. 
2. Amphiarthrosis-Mixed Articulations. 
In this form of articulation the contiguous osseous surfaces are either connected 
together by broad flattened disks of fibro-cartilage which adhere to the end of each 
bone, as in the articulation between the bodies of the vertebrae, or else the articu- 
lating surfaces are covered with fibro-cartilage, partially lined by synovial mem- 
brane, and connected together by external ligaments, as in the sacro-iliac and pubic 
symphyses, both these forms being capable of limited motion in every direction. 
The former resemble the synarthrodial joints in the continuity of their surfaces and 
absence of synovial sac; the latter, the diarthrodial. These joints occasionally 
become obliterated in old age, as is frequently the case in the pubic articulation 
and occasionally in the intervertebral and sacro-iliac. 
3. Diarthrosis-Movable Articulations. 
This form of articulation includes the greater number of the joints in the body, 
mobility being their distinguishing character. They are formed by the approxima- 
tion of two contiguous bony surfaces covered with cartilage, connected by ligaments, 
and lined by synovial membrane. The varieties of joints in this class have been 
determined by the kind of motion permitted in each ; they are six in number- 
Arthrodia, Enarthrosis, Ginglymus, Diarthrosis rotatoria, Condyloid, and Articula- 
tions by Reciprocal Reception. 
Arthrodia is that form of joint which admits of a gliding movement; it is 
formed by the approximation of plane surfaces, or one slightly concave, the other 
slightly convex, the amount of motion between them being limited by the ligaments CLASSIFICATION OF JOINTS. 
299 
Table of the Different Kinds of Articulations. 
Dentata, having 
tooth-like processes. 
As in interparietal 
suture. 
Serrata, having ser- 
rated edges, like the 
teeth of a saw. 
As in interfrontal 
suture. 
Limbosa, having bev- 
elled margins and den- 
tated processes. 
As in fronto-parietal 
suture. 
Sutura vera 
(true), articulate by 
indented borders. 
Sutura, articu- 
lation by processes 
and indentations 
interlocked togeth- 
er. 
Squamosa, formed 
by thin bevelled mar- 
gins overlapping each 
other. 
As in squamo-pari- 
etal suture. 
Harmonia, formed 
by the apposition of 
contiguous rough sur- 
faces. 
As in intermaxillary 
suture. 
Synarthrosis, or Im- 
movable Joint. Sur- 
faces separated by fi- 
brous membrane, with- 
out any intervening 
synovial cavity, and 
immovably connected 
with each other. 
As in joints of cra- 
nium and face (except 
lower jaw). 
Sutura notha 
(false), articulate by 
rough surfaces. 
Schindylesis.-Articulation formed by the reception of a thin plate 
of one bone into a fissure of another. 
As in articulation of rostrum of sphenoid with vomer. 
Gomphosis.-Articulation formed by the insertion of a conical pro- 
cess into a socket. 
The teeth. 
1. Surfaces connected by fibro-cartilage, not separated by synovial 
membrane, and having limited motion. As in joints between bodies 
of vertebrae. 
2. Surfaces covered by fibro-cartilage, lined by a partial synovial 
membrane. As in sacro-iliac and pubic symphyses. 
A mphiarthrosi s- 
Mixed Articulation. 
Arthrodia.-Gliding joint; articulations by plane surfaces, which 
glide upon each other. As in sterno- and acromio-clavicular articula- 
tions. 
Enarthrosis.-'Ball-and-socket joint, capable of motion in all direc- 
tions. Articulations by a globular head received into a cup-like cavity. 
As in hip- and shoulder-joints. 
Ginglymus --Hinge-joint; motion limited to two directions, for- 
ward and backward. Articular surfaces fitted together so as to per- 
mit of movement in one plane. As in the elbow, ankle, and knee. 
Diarthrosis Rotatoria, or Lateral Ginglymus.-Articulation by a 
pivot process turning within a ring or ring around a pivot. As in 
superior radio-ulnar articulation and atlo-axoid joint. 
Condyloid.-Ovoid head received into elliptical cavity. Movements 
in every direction except axial rotation. As the wrist-joint. 
Reciprocal Reception.-Articular surfaces inversely convex in one 
direction and concave in the other. Movement in every direction ex- 
cept axial rotation. As in the metacarpo-phalangeal joint of the thumb. 
Diarthrosis - Mov- 
able Joint. 
or osseous processes surrounding the articulation, as in the articular processes of the 
vertebrm, temporo-maxillary, sterno- and acromio-clavicular, carpal, superior tibio- 
fibular, and tarsal joints. 
Enarthrosis is that form of joint which is capable of motion in all directions. 
It is formed by the reception of a globular head into a deep cup-like cavity (hence 
the name ball-and-socket}, the parts being kept in apposition by a capsular ligament 
strengthened by accessory ligamentous bands. Examples of this form of articulation 
are found in the hip and shoulder. 
Ginglymus or Hinge-joint (yZyy7o/zoc, a hinge).-In this form of joint the artic- 300 
ARTICULA TIONS. 
ular surfaces are moulded to each other in such a manner as to permit motion only 
in two directions, forward and backward, the extent of motion at the same time 
being considerable. The articular surfaces are connected together by strong lateral 
ligaments, which form their chief bond of union. The most perfect form of gingly- 
mus is the elbow; the knee and ankle are less perfect, as they allow a slight degree 
of rotation or lateral movement in certain positions of the limb. 
Diarthrosis Rotatoria (Lateral Ginglymus).-Where the movement is limited 
to rotation, the joint is formed by a pivot-like process turning within a ring or the 
ring on the pivot, the ring being formed partly of bone, partly of ligament. In the 
articulation of the odontoid process of the axis with the atlas the ring is formed in 
front by the anterior arch of the atlas; behind, by the transverse ligament: here 
the ring rotates round the odontoid process. In the superior radio-ulnar articulation 
the ring is formed partly by the lesser sigmoid cavity of the ulna; in the rest of 
its extent by the orbicular ligament; here the head of the radius rotates within 
the ring. 
Condyloid Articulations.-In this form of joint an ovoid articular head or 
condyle is received into an elliptical cavity in such a manner as to permit of flex- 
ion and extension, adduction and abduction, and circumduction, but no axial rota- 
tion. The articular surfaces are connected together by anterior, posterior, and 
lateral ligaments. An example of this form of joint is found in the wrist. 
Articulations by Reciprocal Reception.-In this variety the articular sur- 
faces are concavo-convex ; that is to say, they are inversely convex in one direction 
and concave in the other. The movements are the same as in the preceding form; 
that is to say, there is flexion, extension, adduction, abduction, and circumduction, 
but no axial rotation. The articular surfaces are connected by a capsular ligament. 
The best example of this form of joint is the metacarpo-phalangeal joint of the 
thumb. 
The Kinds of Movement admitted in Joints. 
The movements admissible in joints may be divided into four kinds-gliding, 
angular movement, circumduction, and rotation. These movements are often, 
however, more or less combined in the various joints, so as to produce an infinite 
variety, and it is seldom that we find only one kind of motion in any particular 
joint. 
Gliding movement is the most simple kind of motion that can take place in a 
joint, one surface gliding or moving over another without any angular or rotatory 
movement. It is common to all movable joints, but in some, as in the articula- 
tions of the carpus and tarsus, it is the only motion permitted. This movement is 
not confined to plane surfaces, but may exist between any two contiguous surfaces 
of whatever form, limited by the ligaments which enclose the articulation. 
Angular movement occurs only between the long bones, and by it the angle 
between the two bones is increased or diminished. It may take place in four direc- 
tions-forward and backward, constituting flexion and extension, or inward and out- 
ward, constituting adduction and abduction. The strictly ginglymoid or binge joints 
admit of flexion and extension only. Abduction and adduction, combined with 
flexion and extension, are met with in the more movable joints, as in the hip, 
shoulder, and metacarpal joint of the thumb, and partially in the wrist. 
Circumduction is that limited degree of motion which takes place between the 
head of a bone and its articular cavity whilst the extremity and sides of the limb 
are made to circumscribe a conical space, the base of which corresponds with the 
inferior extremity of the limb, the apex with the articular cavity; this kind of 
motion is best seen in the shoulder- and hip-joints. 
Rotation is the movement of a bone upon its own axis, the bone retaining the 
same relative situation with respect to the adjacent parts, as in the articulation 
between the atlas and axis, where the odontoid process serves as a pivot around 
which the atlas turns, or in the rotation of the radius upon the humerus, and also 
in the hip and shoulder. OF THE VERTEBRAL COLUMN. 
301 
Action of Muscles.]-The actions of the different joints of a limb 
are combined by means of the long muscles which pass over more than one joint, 
and which [when relaxed and stretched to their greatest length] act to a certain 
extent as elastic ligaments in restraining certain actions of one joint, except when 
combined with corresponding movements of the other, these latter movements being 
usually in the opposite direction. Thus, the shortness of the hamstring muscles 
prevents complete flexion of the hip unless the knee-joint be also flexed, so as to 
bring their attachments nearer together. The uses of this arrangement are three- 
fold: 1. It co-ordinates the kinds of movement which are the most habitual and 
necessary, and enables them to be performed with the least expenditure of power. 
"Thus in the usual gesture of the arms, whether in grasping or rejecting, the shoul- 
der and the elbow are flexed simultaneously and simultaneously extended," in con- 
sequence of the passage of the Biceps and Triceps cubiti over both joints. 2. It 
enables the short muscles which pass over only one joint to act upon more than one. 
" Thus if the Rectus femoris remain tonically of such length that, when stretched 
over the extended hip, it compels extension of the knee, then the Gluteus maximus 
becomes not only an extensor of the hip, but an extensor of the knee as well." 
3. It provides the joints with ligaments, which, while they are of very great power 
in resisting movements to an extent incompatible with the mechanism of the joint, 
at the same time spontaneously yield when necessary. " Taxed beyond its strength 
a ligament will be ruptured, whereas a contracted muscle is easily relaxed; also, if 
neighboring joints be united by ligaments, the amount of flexion or extension of 
each must remain in constant proportion to that of the other; while if the union 
be by muscles, the separation of the points of attachment of those muscles may vary 
considerably in different varieties of movement, the muscles adapting themselves 
tonically to the length required." The quotations are from a very interesting paper 
by Dr. Cleland in the Journal of Anatomy and Physiology, No. 1, 1866, p. 85, 
by whom I believe this important fact in the mechanism of joints was first clearly 
pointed out, though it has been independently observed afterward by other anatomists. 
[It is very important that the surgeon should remember this ligamentous action of 
muscles in making passive motion-for instance, at the wrist after Colles' fracture, 
If the fingers be extended, the wrist can be flexed to a right angle. If, however, 
they be first flexed, as in "making a fist," flexion at the wrist is quickly limited to 
from forty to fifty degrees in different persons, and is very painful beyond that point. 
Hence passive motion here should be made with the fingers extended. In the leg, 
when flexing the hip, the knee should be flexed.1] 
The articulations may be arranged into those of the trunk, those of the upper 
extremity, and those of the lower extremity. 
ARTICULATIONS OF THE TRUNK. 
I, Of the vertebral column. 
II. Of the atlas with the axis. 
III. Of the atlas with the occipital bone. 
IV. Of the axis with the occipital bone. 
V. Of the lower jaw. 
VI. Of the ribs with the vertebrae. 
These may be divided into the following groups, viz.: 
VII. Of the cartilages of the ribs with 
the sternum and with each other. 
VIII. Of the sternum. 
IX. Of the vertebral column with the 
pelvis. 
X. Of the pelvis. 
The different segments of the spine are connected together by ligaments, which 
admit of the same arrangement as the Vertebrae. They may be divided into five 
sets: 1, Those connecting the bodies of the vertebrae; 2, those connecting the 
I. Articulations of the Vertebral Column. 
[x A beautiful illustration of this is seen in the perching of birds, whose toes are forced to clasp 
the perch by just such a passive ligamentous action so soon as they stoop. Hence they can go to 
sleep and not fall off the perch.] 302 
ARTICULATIONS. 
laminoe ; 3, those connecting the articular processes; 4, those connecting the 
spinous processes; 5, that of the transverse processes. 
The articulations of the bodies of the vertebrae with each other form a series 
of amphiarthrodial joints; those between the articular processes form a series of 
arthrodial joints. 
1. The Ligaments of the Bodies. 
Anterior Common Ligament. 
Intervertebral Substance. 
Posterior Common Ligament. 
The Anterior Common Ligament (Figs. 236, 237, 244, 247) is a broad and 
strong band of ligamentous fibres which extends along the front surface of the 
bodies of the vertebrae from the axis to the sacrum. It is broader below than 
above, thicker in the dorsal than in the cervical or lumbar regions, and somewhat 
thicker opposite the front of the body of each vertebra than opposite the inter- 
vertebral substance. It is attached above to the body of the axis by a pointed 
process which is connected with the tendon of insertion of the Longus colli muscle, 
and extends down as far as the upper bone of the sacrum. It consists of dense 
longitudinal fibres, which are intimately adherent to the intervertebral substance 
and the prominent margins of the vertebrae, but less closely to the middle of the 
bodies. In the latter situation the fibres are exceedingly thick, and serve to fill up 
the concavities on their front surface and to make the anterior surface of the spine 
more even. This ligament is composed of several layers of fibres which vary in 
length, but are closely interlaced with each other. The most superficial or longest 
fibres extend between four or five vertebrae. A second subjacent set extend between 
ANTERIOR 
COMMON 
LICT 
POSTERIOR 
COMMON 
Fig. 236. 
Vertical Section of Two Vertebrae and their Ligaments, from the Lumbar Region. 
two or three vertebrae, whilst a third set, the shortest and deepest, extend from one 
vertebra to the next. At the side of the bodies the ligament consists of a few 
short fibres which pass from one vertebra to the next, separated from the median 
portion by large oval apertures for the passage of vessels. OF THE VERTEBRAL COLUMN. 
303 
The Posterior Common Ligament (Figs. 236, 240) is situated within the 
spinal canal, and extends along the posterior surface of the bodies of the vertebrae 
from the body of the axis above, where it is continuous with the occipito-axoid 
ligament, to the sacrum below. It is broader at the upper than at the lower part 
of the spine, and thicker in the dorsal than in the cervical or lumbar regions. In 
the situation of the intervertebral substance and contiguous margins of the vertebrae, 
where the ligament is more intimately adherent, it is broad, and presents a series 
of dentations with intervening concave margins; but it is narrow and thick over 
the centre of the bodies, from which it is separated by the vena? basis vertebrce. 
This ligament is composed of smooth, shining, longitudinal fibres, denser and 
more compact than those of the anterior ligament, and composed of a superficial 
layer occupying the interval between three or four vertebrae, and of a deeper layer 
which extends between one vertebra and the next adjacent to it. It is separated 
from the dura mater of the spinal cord by some loose connective tissue very liable 
to serous infiltration. 
The Intervertebral Substance (Fig. 236) is a lenticular disk of fibro-cartilage 
interposed between the adjacent surfaces of the bodies of the vertebrae from the 
axis to the sacrum, and forming the chief bond of connection between those bones. 
These disks vary in shape, size, and thickness in different parts of the spine. In 
shape they accurately correspond with the surfaces of the bodies between which 
they are placed, being oval in the cervical and lumbar regions and circular in the 
dorsal. Their size is greatest in the lumbar region. In thickness they vary not 
only in the different regions of the spine, but in different parts of the same disk : 
thus, they are much thicker in front than behind in the cervical region, and also in 
the lumbar, but they are uniformly thick in the dorsal region. They thus con- 
tribute in a great measure to the curvatures of the spine in the neck and loins, 
whilst the concavity of the dorsal region is chiefly due to the shape of the bodies 
of the vertebrae. The intervertebral disks form about one-fourth of the spinal 
column, exclusive of the first two vertebrae; they are not equally distributed, 
however, between the various bones, the dorsal portion of the spine having, in 
proportion to its length, a much smaller quantity than in the cervical and lumbar 
regions, which necessarily gives to the latter parts greater pliancy and freedom of 
movement. The intervertebral disks are adherent by their surfaces to a thin layer 
of cartilage which covers the upper and under surfaces of the bodies of the verte- 
brae, and by their circumference are closely connected in front to the anterior and 
behind to the posterior common ligament, whilst in the dorsal region they are con- 
nected laterally, by means of the interarticular ligament, to the heads of those ribs 
which articulate with two vertebrae; they consequently form part of the articular 
cavities in which the heads of these bones are received. 
The intervertebral substance is composed at its circumference of laminae of 
fibrous tissue and fibro-cartilage, and at its centre of a soft, elastic, pulpy matter. 
The laminae are arranged concentrically one within the other, the outermost con- 
sisting of ordinary fibrous tissue, but the others and more numerous consisting of 
white fibro-cartilage. These plates are not quite vertical in their direction, those 
near the circumference being curved outward and closely approximated, whilst those 
nearest the centre curve in the opposite direction and are somewhat more widely 
separated. The fibres of which each plate is composed are directed, for the most 
part, obliquely from above downward; the fibres of an adjacent plate have an 
exactly opposite arrangement, varying in their direction in every layer, so that 
the fibres of one layer are directed across those of another, like the limbs of the 
letter X. In some few instances horizontal fibres may be observed. This laminar 
arrangement belongs to about the outer half of each disk, the central part being 
occupied by a soft, pulpy, highly elastic substance of a yellowish color, which 
rises up considerably above the surrounding level when the disk is divided hori- 
zontally. This substance presents no concentric arrangement, and consists of a 
fine fibrous matrix containing cells united to form a reticular structure. The 
pulpy matter, which is especially well developed in the lumbar region, is the 304 
ARTICULA TIONS. 
remains of the chorda dorsalis, and, according to Luschka, contains a small 
synovial cavity in its centre. 
[The intervertebral disks are compressible. In 287 soldiers measured by M. 
Robert the measurement in the erect posture was on an average 65.28 inches, and 
when in the horizontal, 65.79-a difference of half an inch.] 
2. Ligaments connecting the Laminae. 
Ligamenta Subflava. 
The Ligamenta Subflava (Fig. 236) are interposed between the laminae of the 
vertebrae from the axis to the sacrum. They are most distinct when seen from the 
interior of the spinal canal; when viewed from the outer surface they appear short, 
being overlapped by the laminae. Each ligament consists of two lateral portions, 
which commence on each side at the root of either articular process, and pass back- 
ward to the point where the laminae converge to form the spinous process, where 
their margins are thickest, and separated by a slight interval filled up with areolar 
tissue. These ligaments consist of yellow elastic tissue, the fibres of which, almost 
perpendicular in direction, are attached to the anterior surface of the margin of the 
lamina above, and to the posterior surface, as well as to the margin of the lamina 
below. In the cervical region they are thin in texture, but very broad and long; 
they become thicker in the dorsal region, and in the lumbar acquire very consider- 
able thickness. Their highly elastic property serves to preserve the upright pos- 
ture and to assist in resuming it after the spine has been flexed. These ligaments 
do not exist between the occiput and atlas or between the atlas and axis. 
3. Ligaments connecting the Articular Processes. 
Capsular. 
The Capsular Ligaments (Fig. 238) are thin and loose ligamentous sacs 
attached to the contiguous margins of the articulating processes of each vertebra 
through the greater part of their circumference, and completed internally by the 
ligamenta subflava. They are longer and looser in the cervical than in the dorsal 
or lumbar regions. The capsular ligaments are lined on their inner surface by 
synovial membrane. 
4. Ligaments connecting the Spinous Processes. 
The Interspinous Ligaments (Fig. 236), thin and membranous, are interposed 
between the spinous processes. Each ligament extends from the root to near the 
summit of each spinous process, and connects together their adjacent margins. 
They are narrow and elongated in the dorsal region, broader, quadrilateral in 
form, and thicker in the lumbar region, and only slightly developed in the neck. 
The Supraspinous Ligament is a strong fibrous cord which connects together 
the apices of the spinous processes from the seventh cervical to the spinous pro- 
cesses of the sacrum. It is thicker and broader in the lumbar than in the dorsal 
region, and intimately blended in both situations with the neighboring aponeurosis. 
The most superficial fibres of this ligament connect three or four vertebrae; those 
deeper-seated pass between two or three vertebrae; whilst the deepest connect the 
contiguous extremities of neighboring vertebrae. It is continued upward to the 
external occipital protuberance, as the ligamentum nuchae, which in the human 
subject is thin and forms merely an intermuscular septum. 
Interspinous. 
Supraspinous. 
5. Ligaments connecting the Transverse Processes. 
Intertransverse. 
The Intertransverse Ligaments consist of bundles of fibres interposed 
between the transverse processes. In the cervical region they consist of a few OF THE VERTEBRAL COLUMN. 
305 
irregular, scattered fibres; in the dorsal they are rounded cords intimately con- 
nected with the deep muscles of the back ; in the lumbar region they are thin 
and membranous. 
Actions.-The movements permitted in the spinal column are, Flexion, Exten- 
sion, Lateral Movement, Circumduction, and Rotation. 
In Flexion, or movement of the spine forward, the anterior common ligament is 
relaxed and the intervertebral substances are compressed in front, while the poste- 
rior common ligament, the ligamenta subflava, and the inter- and supra-spinous liga- 
ments are stretched, as well as the posterior fibres of the intervertebral disks. The 
interspaces between the laminae are widened, and the inferior articular processes of 
the vertebrae above glide upward upon the articular processes of the vertebrae below. 
Flexion is the most extensive of all the movements of the spine. 
In Extension, or movement of the spine backward, an exactly opposite disposi- 
tion of the parts takes place. This movement is not extensive, being limited 
by the anterior common ligament and by the approximation of the spinous pro- 
cesses. 
Flexion and extension are most free in the lower part of the lumbar region, 
between the third and fourth and fourth and fifth lumbar vertebrae; above the 
third they are much diminished, and reach their minimum in the middle and upper 
part of the back. They increase again in the neck, the capability of motion back- 
ward from the upright position being in this region greater than that of the motion 
forward, whereas in the lumbar region the reverse is the case. 
In Lateral Movement the sides of the intervertebral disks are compressed, the 
extent of motion being limited by the resistance offered by the surrounding liga- 
ments and by the approximation of the transverse processes. This movement may 
take place in any part of the spine, but is most free in the neck and loins. 
Circumdiiction is very limited, and is produced merely by a succession of the 
preceding movements. 
Rotation is produced by the twisting of the intervertebral substances; this, 
although only slight between any two vertebrae, produces a great extent of move- 
ment when it takes place in the whole length of the spine, the front of the column 
being turned to one or the other side. This movement takes place only to a slight 
extent in the neck, but is freer in the upper part of the dorsal region, and is alto- 
gether absent in the lumbar region. 
It is thus seen that the cervical region enjoys the greatest extent of each variety 
of movement, flexion and extension especially being very free. In the dorsal region 
the three movements of flexion, extension, and circumduction are only permitted to 
each side to a slight extent, while rotation is very free in the upper part and ceases 
below. In the lumbar region there is free flexion, extension, and lateral movement, 
but no rotation. [The rotation of the head and atlas on the axis amounts to about 
25°, and of the remaining cervical and upper dorsal vertebrae to about 45° more, 
making 70° in all in the neck. In the dorsal region about 30° more are added, to 
which the hips add 65° to 80° more, a total rotation of 165° to 180°. The various 
movements of the spine are beautifully seen in the well-known statues of Psyche, 
the Wrestlers, the Dying Gladiator, Angelo's Night and Morning, etc., and the 
living model may be made to assume these and many other positions.] 
As Professor Humphry has pointed out, the movements permitted are mainly 
due to the shape and position of the articulating processes. In the loins the infe- 
rior articulating processes, turned outward and embraced by the superior, render 
rotation in this region of the spine impossible, whilst there is nothing to prevent a 
sliding upward and downward of the surfaces on each other, so as to allow of flex- 
ion and extension. In the dorsal region, on the other hand, the articulating pro- 
cesses, by their direction and mutual adaptation, especially at the upper part of the 
series, permit of rotation, but prevent extension and flexion, while in the cervical 
region the greater obliquity and lateral slant of the articular processes allows not 
only flexion and extension, but also rotation. 
The principal muscles which produce extension are the fourth layer of the mus- 306 
ARTICULATIONS. 
cles of the back, assisted in the neck by the Splenius, Rectus capitis posticus minor, 
and the Superior oblique. 
Flexion is produced by the Sterno-mastoid, Rectus capitis anticus major and 
minor, the Scaleni, the abdominal muscles, and the Psoas magnus. Lateral motion 
is produced by the fourth layer of the muscles of the back, by the Splenius and the 
Scaleni, the muscles of one side only acting; and rotation by the action of the fol- 
lowing muscles of.one side only-viz. the Sterno-mastoid, the Recti antici, the 
Scaleni, the Multifidus spinse, the Complexus, the Rectus capitis posticus major, 
Inferior oblique, and the abdominal muscles. 
II. Articulations of the Atlas with the Axis. 
The articulation of the Atlas with the Axis is of a complicated nature, compris- 
ing no less than four distinct joints. There is a lateral ginglymus joint (diarthrosis 
rotatoria) between the odontoid process of the axis and the ring formed between the 
anterior arch of the atlas and the transverse ligament. (See Fig. 239.) Here there 
are two joints-one in front, between the posterior surface of the anterior arch of 
the atlas and the front of the odontoid process (the atlo-odontoid joint of Cruveil- 
hier) ; the other between the anterior surface of the transverse ligament and the 
back of the process (the syndesmo-odontoid joint). Between the articulating pro- 
cesses of the two bones there is a double arthrodia or gliding joint. The ligaments 
which connect these bones are the 
Two Anterior Atlo-axoid. 
Posterior Atlo-axoid. 
Transverse. 
Two Capsular. 
Of the Two Anterior Atlo-axoid Ligaments (Fig. 237), the more superficial 
is a rounded cord situated in the middle line; it is attached above to the tubercle 
Fig. 237. 
OCCI PiTO- 
-ATLOID 
J CAPSULAR LIG'T &. 
( SYNOVIAL MEMBRANE 
ATLO- 
-AXOIO 
J CAPSULAR LIG'T & 
(SYNOVIAL MEMBRANE 
Occipito-atloid and Atlo-axoid Ligaments, front view. 
on the anterior arch of the atlas, below to the base of the odontoid process and to 
the front of the body of the axis. The deeper ligament is a membranous layer, 
attached above to the lower border of the anterior arch of the atlas, below to the OF THE ATLAS WITH THE AXIS 
307 
base of the odontoid process and front of the body of the axis. These ligaments 
are in relation, in front, with the Recti antici majores. 
Fig. 238. 
Occipmtl Bane 
Arch for passage of VertebralArr j 
£ Cirvtcal nerve- 
Occipito-atloid and Atlo-axoid Ligaments, posterior view. 
The Posterior Atlo-axoid Ligament (Fig. 238) is a broad and thin membran- 
ous layer, attached above to the lower border of the posterior arch of the atlas, below 
Fig. 239. 
for Sfii/nalCord and. 
its Membranes 
Articulation between Odontoid Process and Atlas. 
to the upper edge of the laminae of the axis. This ligament supplies the place of 
the ligamenta subflava, and is in relation, behind, with the. Inferior oblique muscles. 
The Transverse Ligament1 (Figs. 239, 240) is a thick and strong ligamentous 
1 It has been found necessary to describe the transverse ligament with those of the atlas and axis ; 
but the student must remember that it is really a portion of the mechanism by which the movements 
of the head on the spine are regulated, so that the connections between the atlas and axis ought 
always to be studied together with those between the latter bones and the skull. 308 
ARTICULATIONS. 
band which arches across the ring of the atlas, and serves to retain the odontoid 
process in firm connection with its anterior arch. This ligament is flattened from 
before backward, broader and thicker in the middle than at either extremity, and 
firmly attached on each side of the atlas to a small tubercle on the inner surface of 
its lateral mass. As it crosses the odontoid process a small fasciculus is derived from 
its upper and lower borders, the former, passing upw'ard, to be inserted into the basi- 
lar process of the occipital bone ; the latter, downward, to be attached to the root of 
the odontoid process; hence the whole ligament has received the name of cruciform. 
Fig. 240. 
occj pito - axoid licamemt . divided 8c turned barb 
I \ 
the Vertical fiurtton 
Oj ODONTOID LI CT? 
OCC«P'TO( CAPSULAR LICT & 
atlOid \ Synovial /ne-mbranj 
ATLOf CAPSULAR LIGT * 
axoi d [ Synovial membrane 
Occipito-axoid and Atlo-axoid Ligaments, posterior view, obtained by removing the arches of the vertebra? and 
the posterior part of the skull. 
The transverse ligament divides the ring of the atlas into two unequal parts: of 
these the posterior and larger serves for the transmission of the cord and its mem- 
branes and the spinal accessory nerves; the anterior and smaller contains the odon- 
toid process. Since the lower border of the space between the anterior arch of the 
atlas and the transverse ligament is smaller than the upper (because the transverse 
ligament embraces firmly the narrow neck of the odontoid process), this process is 
retained in firm connection with the atlas when all the other ligaments have been 
divided. 
The Capsular Ligaments are two thin and loose capsules, connecting the artic- 
ular surfaces of the atlas and axis, the fibres being strongest on the anterior and 
external part of the articulation. 
There are four synovial membranes in this articulation-one lining the inner 
surface of each of the capsular ligaments; one between the anterior surface of the 
odontoid process and the anterior arch of the atlas, the atlo-odontoid joint; and 
one between the posterior surface of the odontoid process and the transverse 
ligament, the syndesmo-odontoid joint. The latter often communicates with 
those between the condyles of the occipital bone and the articular surfaces of the 
atlas. 
Actions.-This joint is capable of great mobility, and allows the rotation of 
the atlas (and, with it, of the cranium) upon the axis, the extent of rotation being 
limited by the odontoid ligaments. The principal muscles by which this action is OF THE AXIS WITH THE OCCIPITAL BONE. 
309 
produced are the Rectus capitis posticus major and the Obliquus inferior, assisted 
to a certain extent by the Rectus capitis anticus major and by other muscles which 
pass obliquely from the spine to the head, as the Trachelo-mastoid. 
Articulations of the Spine with the Cranium. 
The ligaments connecting the spine with the cranium may be divided into two 
sets, those connecting the occipital bone with the atlas, and those connecting the 
occipital bone with the axis. 
IH. Articulation of the Atlas with the Occipital Bone. 
This articulation is a double arthrodia. Its ligaments are the 
Two Anterior Occipito-atloid. 
Posterior Occipito-atloid. 
Two Lateral Occipito-atloid. 
Two Capsular. 
Of the Two Anterior Ligaments (Fig. 237), the superficial is a strong, narrow, 
rounded cord, attached above to the basilar process of the occiput, below to the 
tubercle on the anterior arch of the atlas: the deeper ligament is a broad and thin 
membranous layer which passes between the anterior margin of the foramen mag- 
num above and the whole length of the upper border of the anterior arch of the 
atlas below. This ligament is in relation in front with the Recti antici minores, 
behind with the odontoid ligaments. 
The Posterior Occipito-atloid Ligament (Fig. 238) is a very broad but thin 
membranous lamina intimately blended with the dura mater. It is connected above 
to the posterior margin of the foramen magnum, below to the upper border of the 
posterior arch of the atlas. This ligament is incomplete at each side, and forms, 
with the superior intervertebral notch, an opening for the passage of the vertebral 
artery and suboccipital nerve. It is in relation behind with the Recti postici minores 
and Obliqui superiores, in front with the dura mater of the spinal canal, to which it 
is intimately adherent. 
The Lateral Ligaments are strong fibrous bands directed obliquely upward and 
inward, attached above to the jugular process of the occipital bone, below to the 
base of the transverse process of the atlas. 
The Capsular Ligaments surround the condyles of the occipital bone, and con- 
nect them with the articular surfaces of the atlas; they consist of thin and loose 
capsules which enclose the synovial membrane of the articulation. The synovial 
membranes between the occipital bone and atlas communicate occasionally with that 
between the posterior surface of the odontoid process and transverse ligament. 
Actions.-The movements permitted in this joint are flexion and extension, 
which give rise to the ordinary forward or backward nodding of the head, besides 
slight lateral motion to one or the other side. When either of these actions is car- 
ried beyond a slight extent, the whole of the cervical portion of the spine assists in 
its production. Flexion is mainly produced by the action of the Rectus capitis 
anticus major and minor and the Sterno-mastoid muscles. Extension by the Rec- 
tus capitis posticus major and minor and the Superior oblique; by the Complexus 
and upper fibres of the Trapezius. The Recti laterales are mainly concerned in the 
slight lateral movement. According to Cruveilhier, there is a slight motion of 
rotation in this joint. 
IV. Articulation of the Axis with the Occipital Bone. 
Occipito-axoid. 
Three Odontoid. 
To expose these ligaments the spinal canal should be laid open by removing the 
posterior arch of the atlas, the laminae and spinous process of the axis, and the por- 
tion of the occipital bone behind the foramen magnum, as seen in Fig. 240. 
The Occipito-axoid Ligament (apparatus ligamentosus colli} is situated at the 310 
ARTICULATIONS. 
upper part of the front surface of the spinal canal. It is a broad and strong liga- 
mentous band which covers the odontoid process and its ligaments, and appears to 
be a prolongation upward of the posterior common ligament of the spine. It is 
attached below to the posterior surface of the body of the axis, and, becoming 
expanded as it ascends, is inserted into the basilar groove of the occipital bone in 
front of the foramen magnum, where it becomes blended with the dura mater of 
the skull. 
Relations.-By its anterior surface it is intimately connected with the trans- 
verse ligament, by its posterior surface with the dura mater. By cutting this lig- 
ament across and turning its ends aside the transverse and odontoid ligaments 
are exposed. 
The Odontoid or Check Ligaments (alar ligaments) are strong, rounded, 
fibrous cords which arise one on either side of the apex of the odontoid process, 
and, passing obliquely upward and outward, are inserted into the rough depressions 
on the inner side of the condyles of the occipital bone. In the triangular interval 
left between these ligaments and the margin of the foramen magnum a third strong 
ligamentous band (ligamentum suspensorium) may be seen, which passes almost per- 
pendicularly from the apex of the odontoid process to the anterior margin of the 
foramen, being intimately blended with the anterior occipito-atloid ligament and 
upper fasciculus of the transverse ligament of the atlas. 
Actions.-The odontoid ligaments serve to limit the extent to which rotation 
of the cranium may be carried; hence they have received the name of check 
ligaments. 
In addition to these ligaments, which connect the atlas and axis to the skull, the 
ligamentum nuchse must be regarded as one of the ligaments by which the spine is 
connected with the cranium. (For a description of this ligament see the description 
of the Trapezius muscle.) 
This is a double or bilateral condyloid joint; the parts entering into its forma- 
tion are, on each side, the anterior part of the glenoid cavity of the temporal bone 
V. Temporo-maxillary Articulation. 
Fig. 241. 
Temporal hone 
Tnfe rior 
Maxi I La 
Temporo-maxillary Articulation, external view. TEMP ORO- MA XIL LA RY ARTICULATION. 
311 
and the eminentia articularis above with the condyle of the lower jaw below. The 
ligaments are the following : 
External Lateral. 
Internal Lateral. 
Stylo-maxillary. 
Capsular. 
The External Lateral Ligament (Fig. 241) is a short, thin, and narrow fascic- 
ulus attached above to the outer surface of the zygoma and to the rough tubercle 
on its lower border; below, to the outer surface and posterior border of the neck of 
the lower jaw. This ligament is broader above than below; its fibres are placed 
parallel with one another and directed obliquely downward and backward. Exter- 
nally, it is covered by the parotid gland and by the integument. Internally, it is 
in relation with the interarticular fibro-cartilage and the synovial membrane. 
The Internal Lateral Ligament (Fig. 242) is a long, thin, and loose band which 
is attached above to the spinous process of the sphenoid bone, and, becoming broader 
as it descends, is inserted into the inner margin of the dental foramen. Its outer sur- 
face is in relation above with the 
External pterygoid muscle; lower 
down it is separated from the neck 
of the condyle by the internal 
maxillary artery; and still more 
inferiorly the inferior dental ves- 
sels and nerve separate it from the 
ramus of the jaw. Internally, it 
is in relation with the internal 
pterygoid. 
The Stylo-maxillary Liga- 
ment is a thin aponeurotic cord 
which extends from near the apex 
of the styloid process of the tem- 
poral bone to the angle and poste- 
rior border of the ramus of the 
lower jaw, between the Masseter 
and Internal pterygoid muscles. 
This ligament separates the paro- 
tid from the submaxillary gland, 
and has attached to its inner side 
part of the fibres of origin of the 
Stylo-glossus muscle. Although 
usually classed among the liga- 
ments of the jaw, it can only be considered as an accessory in the articulation. It 
is derived from the deep cervical fascia. 
Along with the stylo-maxillary ligament may be described the stylo-hyoid liga- 
ment, although it is in no way connected with the functions of the lower jaw. This 
is a fibrous cord which continues the styloid process down to the hyoid bone, being 
attached to the tip of the former and the small cornu of the latter. It is often more 
or less ossified. 
The Capsular Ligament forms a thin and loose ligamentous capsule attached 
above to the circumference of the glenoid cavity and the articular surface imme- 
diately in front; below, to the neck of the condyle of the lower jaw. It consists 
of a few thin scattered fibres, and can hardly be considered as a distinct ligament; 
it is thickest at the back part of the articulation? 
The Interarticular Fibro-cartilage (Fig. 243) is a thin plate of an oval form 
placed horizontally between the condyle of the jaw and the glenoid cavity. Its 
Interarticular Fibro-cartilage. 
Fig. 242. 
Temporo-maxillary Articulation, internal view. 
1 Dr. Humphry describes the internal portion of the capsular ligament separately as the short 
internal lateral ligament; and it certainly seems as deserving of a separate description as the external 
lateral ligament is. 312 
ARTICULATIONS. 
upper surface is concavo-convex from before backward and a little convex trans- 
versely, to accommodate itself to the form of the glenoid cavity. Its under sur- 
face, wThere it is in contact with the 
condyle, is concave. Its circumfer- 
ence is connected externally to the 
external lateral ligament, internally 
to the capsular ligament, and in 
front to the tendon of the External 
pterygoid muscle. It is thicker at 
its circumference, especially behind, 
than at its centre, where it is some- 
times perforated. The fibres of which 
it is composed have a concentric ar- 
rangement, more apparent at the cir- 
cumference than at the centre. Its 
surfaces are smooth, and divide the 
joint into two cavities, each of which 
is furnished with a separate synovial 
membrane. When the fibro-cartilage is perforated the synovial membranes are 
continuous with one another. 
The synovial membranes, two in number, are placed one above and the other 
below the fibro-cartilage. The upper one, the larger and looser of the two, is con- 
tinued from the margin of the cartilage covering the glenoid cavity and eminentia 
articularis on to the upper surface of the fibro-cartilage. The lower one passes 
from the under surface of the fibro-cartilage to the neck of the condyle of the jaw, 
being prolonged downward a little farther behind than in front. 
The Nerves of this joint are derived from the auriculo-temporal and masseteric 
branches of the inferior maxillary. 
Actions.-The movements permitted in this articulation are very extensive. 
Thus, the jaw may be depressed or elevated, or it may be carried forward or back- 
ward or from side to side. It is by the alternation of these movements, performed 
in succession, that a kind of rotatory motion of the lower jaw upon the upper takes 
place, which materially assists in the mastication of the food. 
If the movement of depression is carried only to a slight extent, the condyles 
remain in the glenoid cavities, rotating on a transverse axis against the inter- 
articular fibro-cartilage; but if the depression is considerable, the condyles glide 
from the glenoid fossae on to the articular eminences, carrying with them the inter- 
articular fibro-cartilages, so that in opening the mouth widely the two movements 
are combined; the condyle rotates on a transverse axis and at the same time glides 
forward, carrying the fibro-cartilage with it. When this movement is carried to 
too great an extent-as, for instance, during a convulsive yawn-dislocation of 
the condyle into the zygomatic fossa may occur, the interarticular cartilage being 
displaced forward and the capsular ligament ruptured. When the jaw is elevated 
after forced depression, the condyles and fibro-cartilages return to their original 
position. When the jaw is carried horizontally forward and backward or from side 
to side, a horizontal gliding movement of the fibro-cartilages and condyles upon the 
glenoid cavities takes place in the corresponding direction. 
The lower jaw is depressed by its own weight, assisted by the Platysma, the 
Digastric, the Mylo-hyoid, and the Genio-hyoid. It is elevated by the Temporal, 
Masseter, and Internal pterygoid. It is drawn forward by the External pterygoid, 
Internal pterygoid, and the superficial fibres of the Masseter, and it is drawn backward 
by the deep fibres of the Masseter and the posterior fibres of the Temporal muscle. 
Fig. 243. 
Vertical Section of Temporo-maxillary Articulation. 
VI. Articulations of the Ribs with the Vertebra. 
The articulations of the ribs with the vertebral column may be divided into two 
sets : 1, Those which connect the heads of the ribs with the bodies of the vertebrae ; OF THE RIBS WITH THE VERTEBRAE. 
313 
2, those which connect the necks and tubercles of the ribs with the transverse 
processes. 
1. Articulations between the Heads of the Ribs and the Bodies of 
the Vertebra (Big- 244). 
These constitute a series of arthrodial joints, formed by the articulation of the 
heads of the ribs with the cavities on the contiguous margins of the bodies of the 
dorsal vertebrae, connected together by the following ligaments: 
Anterior Costo-vertebral or Stellate. 
Capsular. 
Interarticular. 
The Anterior Costo-vertebral or Stellate Ligament connects the anterior 
part of the head of each rib with the sides of the bodies of two vertebrae and the 
intervertebral disk between them. It consists of three flat bundles of ligamentous 
Fig. 244. 
Upper Synovial cavity 
INTER-ARTICULAR LICT 
JLmver Synovial cavity 
Costo-vertebral and Costo-transverse Articulations, anterior view. 
fibres which radiate from the anterior part of the head of the rib. The superior 
fasciculus passes upward to be connected with the body of the vertebra above; the 
inferior one descends to the body of the vertebra below; and the middle one, the 
smallest and least distinct, passes horizontally inward, to be attached to the inter- 
vertebral substance. 
Relations.-In front, with the thoracic ganglia of the sympathetic, the pleura, 
and, on the right side, with the vena azygos major; behind, with the interarticular 
ligament and synovial membranes. 
In the first rib, which articulates with a single vertebra only, this ligament does 
not present a distinct division into three fasciculi: its superior fibres, however, pass 
to be attached to the body of the last cervical vertebra, as well as to the body of 
the vertebra with which the rib articulates. In the tenth, eleventh, and twelfth 
ribs also, which likewise articulate with a single vertebra, the division does not 
exist; but the upper fibres of the ligament in each case are connected with the 
vertebra above, as well as that with which the ribs articulate. 314 
ARTICULATIONS. 
The Capsular Ligament is a thin and loose ligamentous bag which surrounds 
the joint between the head of the rib and the articular cavity formed by the junc- 
tion of the vertebrae. It is very thin, firmly connected with the anterior ligament, 
and most distinct at the upper and lower parts of the articulation. 
The Tnterarticular Ligament is situated in the interior of the joint. It con- 
sists of a short band of fibres flattened from above downward, attached by one 
extremity to the sharp crest on the head of the rib, and by the other to the inter- 
vertebral disk. It divides the joint into two cavities which have no communica- 
tion with one another, but are each lined by a separate synovial membrane. In the 
first, tenth, eleventh, and twelfth ribs the interarticular ligament does not exist; 
consequently, there is but one synovial membrane. 
Actions.-The movement of the ribs is limited to elevation and depression, and 
to a slight rotation upward and downward. The former movement is produced by 
the head of the rib moving upon an axis directed transversely through the costo- 
vertebral joint; the latter is a rotation about an axis passing between their verte- 
bral and sternal ends, and produces an inversion or eversion of the ribs. The 
mobility of the different ribs varies very much. The first rib is more fixed than 
the others, on account of the weight of the upper extremity and the strain of the 
ribs beneath ; but on the freshly dissected thorax it moves as freely as the others. 
From the same causes the movement of the second rib is also not very extensive. 
In the other ribs their mobility increases successively down to the last two, which 
are very movable. The ribs are generally more movable in the female than in the 
male. [It should not be overlooked that elevation of the ribs, in consequence of 
their oblique position, pushes the sternum forward, and thus increases the antero- 
posterior capacity of the chest.] 
2. Articulations of the Necks and Tubercles of the Ribs with the 
Transverse Processes (Fig. 245). 
The articular portion of the tubercle of the rib and adjacent transverse process 
form an arthrodial joint provided with a thin capsular ligament attached to the 
Fig. 245. 
ANTERIOR COSTO-TRANSVERSE LI G* DIVIDED 
MIDDLE COSTO-TRANSVERSE Or 
INTEROSSEOUS 
Vert el ral 
\ Foramen / 
POSTERIOR COSTO-TRANSVERSE LICT. 
SYNOVIAL CAVITY 
CAPSULAR MEMBRANE 
Costo-transverse Articulation, seen from above. 
circumference of the articulating surfaces, and enclosing a small synovial membrane 
In the eleventh and twelfth ribs this articulation is wanting. OF THE CARTILAGES OF RIBS WITH STERNUM. 
315 
The ligaments connecting these parts are the 
Anterior Costo-transverse. 
Middle Costo-transverse (Interosseous). 
Posterior Costo-transverse. 
Capsular. 
The Anterior Costo-transverse Ligament (superior or long) is a broad and 
strong band of fibres attached below to the sharp crest on the upper border of the 
neck of each rib, and passing obliquely upward and outward to the lower border 
of the transverse process immediately above. It is broader below than above, 
broader and thinner between the lower ribs than between the upper, and more 
distinct in front than behind. This ligament is in relation, in front, with the 
intercostal vessels and nerves; behind with the Longissimus dorsi. Its internal 
border completes an aperture formed between it and the articular processes, through 
which pass the posterior branches of the intercostal vessels and nerves. Its exter- 
nal border is continuous with a thin aponeurosis which covers the External inter- 
costal muscle. 
The first rib has no anterior costo-transverse ligament. 
The Middle Costo-transverse or Interosseous Ligament consists of short 
but strong fibres which pass between the rough surface on the posterior part of the 
neck of each rib and the anterior surface of the adjacent transverse process. In 
order fully to expose this ligament, a horizontal section should be made across the 
transverse process and corresponding part of the rib, or the rib may be forcibly 
separated from the transverse process and its fibres put on the stretch. 
In the eleventh and twelfth ribs this ligament is quite rudimentary. 
The Posterior Costo-transverse Ligament is a short but thick and strong 
fasciculus which passes obliquely from the summit of the transverse process to the 
rough, non-articular portion of the tubercle of the rib. This ligament is shorter 
and more oblique in the upper than in the lower ribs. Those corresponding to the 
superior ribs ascend, while those of the inferior ribs descend slightly. 
In the eleventh and twelfth ribs this ligament is wanting. 
Actions.-The movement permitted in these joints is limited to a slight gliding 
motion of the articular surfaces one upon the other, the tubercles of the ribs mov- 
ing backward and upward in inspiration, downward and forward in expiration. 
VH. Articulation of the Cartilages of the Ribs with the Sternum, 
etc. (Fig- 246). 
The articulations of the cartilages of the true ribs with the sternum are arthro-< 
dial joints with the exception of the first, in which the cartilage is almost always 
directly united with the sternum, and which must, therefore, be regarded as a syn- 
arthrodial articulation. The ligaments connecting them are the 
Anterior Chondro-sternal. 
Posterior Chondro-sternal. 
Capsular. 
The Anterior Chondro-sternal Ligament is a broad and thin membranous 
band that radiates from the front of the inner extremity of the cartilages of the 
true ribs to the anterior surface of the sternum. It is composed of fasciculi which 
pass in different directions. The superior fasciculi ascend obliquely, the inferior 
pass obliquely downward, and the middle fasciculi horizontally. The superficial 
fibres of this ligament are the longest; they intermingle with the fibres of the liga- 
ments above and below them, with those of the opposite side, and with the tendi- 
nous fibres of origin of the Pectoralis major, forming a thick fibrous membrane 
which covers the surface of the sternum. This is more distinct at the lower than 
at the upper part. 
The Posterior Chondro-sternal Ligament, less thick and distinct than the 316 
ARTICULATIONS. 
Fig. 246. 
continwoubs urith fiternu/Mi 
INTER-ARTICULAR LIG'T 
& 
two Synovial membranes 
Single Synovial 
Membrane 
Intercostal 
Synovial Membrane 
Chondro-sternal, Chondro-xiphoid, and Interchondral Articulations, anterior view. The synovial cavities 
exposed by a vertical section of the sternum and cartilages. 
anterior, is composed of fibres which radiate from the posterior surface of the 
sternal end of the cartilages of the true ribs to the posterior surface of the ster- 
num, becoming blended with the periosteum. 
The Capsular Ligament surrounds the joints formed between the cartilages of 
the true ribs and the sternum. It is very thin, intimately blended with the anterior 
and posterior ligaments, and strengthened at the upper and lower part of the artic- 
ulation by a few fibres which pass from the cartilage to the side of the sternum. 
These ligaments protect the synovial membranes. 
Synovial Membranes.-The cartilage of the first rib is directly continuous 
with the sternum, without any synovial membrane. The cartilage of the second 
rib is connected with the sternum by means of an interarticular ligament attached 
by one extremity to the cartilage of the second rib, and by the other extremity to 
the cartilage which unites the first and second pieces of the sternum. This articula- LIGAMENTS OF THE STERNUM. 
317 
tion is provided with two synovial membranes. That of the third rib has also two 
synovial membranes, and that of the fourth, fifth, sixth, and seventh, each a single 
synovial membrane.1 Thus there are eight synovial cavities on each side in the 
articulations between the costal cartilages of the true ribs and the sternum. They 
may be demonstrated by removing a thin section from the anterior surface of the 
sternum and cartilages, as seen in the figure. After middle life the articular sur- 
faces lose their polish, become roughened, and the synovial membranes appear to be 
wanting. In old age the articulations do not exist, the cartilages of most of the 
ribs becoming continuous with the sternum. The cartilage of the seventh rib, and 
occasionally also that of the sixth, is connected to the anterior surface of the ensi- 
form appendix by a band of ligamentous fibres which varies in length and breadth 
in different subjects. It is called the chondr o-xip>hoid ligament. 
Actions.-The movements which are permitted in the chondro-sternal articula- 
tions are limited to elevation and depression, and these only to a slight extent. 
Articulations of the Cartilages of the Ribs with each other (Interchon- 
dral) (Fig. 246). 
The cartilages of the sixth, seventh, and eighth ribs articulate, by their lower 
borders, with the corresponding margin of the adjoining cartilages by means of a 
small, smooth, oblong-shaped facet. Each articulation is enclosed in a thin capsular 
ligament lined by synovial membrane, and strengthened externally and internally 
by ligamentous fibres (interchondral ligaments) which pass from one cartilage to 
the other. Sometimes the cartilage of the fifth rib, more rarely that of the ninth, 
articulates by its lower border with the adjoining cartilage by a small oval facet; 
more frequently they are connected together by a few ligamentous fibres. Occa- 
sionally the articular surfaces above mentioned are wanting. 
Articulations of the Ribs with their Cartilages (Costo-chondral) (Fig. 
246).. 
The outer extremity of each costal cartilage is received into a depression in the 
sternal end of the ribs and held together by the periosteum. 
VIII. Ligaments of the Sternum. 
The second piece of the sternum is united to the first either by an amphiarthro- 
dial joint-a single piece of true fibro-cartilage uniting the segments-or by a diar- 
throdial joint, in which each bone is clothed with a distinct lamina of cartilage, adhe- 
rent on one side, free and lined with synovial membrane on the other. In the latter 
case the cartilage covering the gladiolus is continued without interruption on to the 
cartilages of the second ribs. Mr. Rivington has found the diarthrodial form of 
joint in about one-third of the specimens examined by him; Mr. Maisonneuve 
more frequently. It appears to be rare in childhood, and is formed, in Mr. Riving- 
ton's opinion, from the amphiarthrodial form by absorption. The diarthrodial joint 
seems to have no tendency to ossify at any age, while the amphiarthrodial is very 
liable to do so, and has been found ossified as early as thirty-four years of age. The 
two segments are further connected by an 
Anterior intersternal ligament, and a 
Posterior intersternal ligament. 
The Anterior Intersternal Ligament consists of a layer of fibres having a 
longitudinal direction; it blends with the fibres of the anterior chondro-sternal 
ligaments on both sides, and with the aponeurosis of origin of the Pectoralis major. 
This ligament is rough, irregular, and much thicker at the lower than at the upper 
part of the bone. 
1 The synovial membrane is sometimes wanting in the sixth and seventh chondro-sternal joints. 318 
ARTICULATIONS. 
The Posterior Intersternal Ligament is disposed in a somewhat similar manner 
on the posterior surface of the articulation. 
IX. Articulation of the Pelvis with the Spine. 
The ligaments connecting the last lumbar vertebra with the sacrum are similar 
to those which connect the segments of the spine with each other-viz.: 1, The 
continuation downward of the anterior and posterior common ligaments; 2, the 
intervertebral substance connecting the flattened oval surfaces of the two bones and 
forming an amphiarthrodial j oint; 3, ligamenta subflava, connecting the arch of the 
last lumbar vertebra with the posterior border of the sacral canal; 4, capsular liga- 
ments connecting the articulating processes and forming a double arthrodia; 5, 
inter- and supra-spinous ligaments. 
The two proper ligaments connecting the pelvis with the spine are the lumbo- 
sacral and ilio-lumbar. 
The Lumbo-sacral Ligament (sacro-vertebral) (Fig. 247) is a short, thick, tri- 
angular fasciculus which is connected above to the lower and front part of the trans- 
Fig. 247. 
ofco7remMnicutu)'n, 
-Bursa of PSOAS ILIACUS 
• Femur 
Articulations of Pelvis and Hip, anterior view. 
verse process of the last lumbar vertebra, passes obliquely outward, and is attached 
below to the lateral surface of the base of the sacrum, becoming blended with the 
anterior sacro-iliac ligament. This ligament is in relation in front with the Psoas 
muscle. 
The Ilio-lumbar Ligament (Fig. 247) passes horizontally outward from the apex 
of the transverse process of the last lumbar vertebra to the crest of the ilium imme- 
diately in front of the sacro-iliac articulation. It is of a triangular form, thick and 
narrow internally, broad and thinner externally. It is in relation, in front, with the 
Psoas muscle; behind, with the muscles occupying the vertebral groove; above, 
with the Quadratus lumborum. OF THE PELVIS. 
319 
X. Articulations of the Pelvis. 
The ligaments connecting the bones of the pelvis with each other may be divided 
into four groups: 1, Those connecting the sacrum and ilium; 2, those passing 
between the sacrum and ischium; 3, those connecting the sacrum and coccyx; 4, 
those between the two pubic bones. 
1. Articulation of the Sacrum and Ilium. 
The sacro-iliac articulation, is an amphiarthrodial joint formed between the lat- 
eral surfaces of the sacrum and ilium. The anterior or auricular portion of each 
articular surface is covered with a thin plate of cartilage, thicker on the sacrum 
than on the ilium. The surfaces of these cartilages in the adult are rough and 
irregular, and separated from one another by a soft yellow pulpy substance. At an 
early period of life, occasionally in the adult, and in the female during pregnancy, 
they are smooth and lined by a delicate synovial membrane. The ligaments con- 
necting these surfaces are the anterior and posterior sacro-iliac. 
The Anterior Sacro-iliac Ligament (Fig. 247) consists of numerous thin liga- 
mentous bands which connect the anterior surfaces of the sacrum and ilium. 
The Posterior Sacro-iliac (Fig. 248) is a strong interosseous ligament situated 
in a deep depression between the sacrum and ilium behind, and forming the chief 
band of connection between those bones. It consists of numerous strong fasciculi 
Fig. 248. 
ANTERIOR or LESSER 
S ACRO-SCIATIC LIG.T. 
Articulations of Pelvis and Hip, posterior view. 
which pass between the bones in various directions. Three of these are of large 
size: the two superior, nearly horizontal in direction, arise from the first and second 
transverse tubercles on the posterior surface of the sacrum, and are inserted into the 
rough, uneven surface at the posterior part of the inner surface of the ilium. The 320 
ARTICULATIONS. 
third fasciculus, oblique in direction, is attached by one extremity to the third 
transverse tubercle on the posterior surface of the sacrum, and by the other to the 
posterior superior spine of the ilium; it is sometimes called the oblique sacro-iliac 
ligament. 
2. Ligaments passing between the Sacrum and Ischium (Fig. 248). 
The Great Sacro-sciatic (Posterior). 
The Lesser Sacro-sciatic (Anterior). 
The Great or Posterior Sacro-sciatic Ligament is situated at the lower and 
back part of the pelvis. It is thin, flat, and triangular in form; narrower in the 
middle than at the extremities; attached by its broad base to the posterior inferior 
spine of the ilium, to the fourth and fifth transverse tubercles on the sacrum, and to 
the lower part of the lateral margin of that bone and the coccyx; passing obliquely 
downward, outward, and forward, it becomes narrow and thick, and at its insertion 
into the inner margin of the tuberosity of the ischium it increases in breadth, and is 
prolonged forward along the inner margin of the ramus, forming what is known as 
the falciform ligament. The free concave edge of this prolongation has attached to 
it the obturator fascia, with which it forms a kind of groove, protecting the internal 
pudic vessels and nerve. One of its surfaces is turned towards the perineum, the 
other toward the Obturator internus muscle. 
The posterior surface of this ligament gives origin, by its whole extent, to fibres 
of the Gluteus maximus. Its anterior surface is united to the lesser sacro-sciatic 
ligament. Its superior border forms the lower boundary of the lesser sacro-sciatic 
foramen. Its lorver border forms part of the boundary of the perineum. It is pierced 
by the coccygeal branch of the sciatic artery and coccygeal nerve. 
The Lesser or Anterior Sacro-sciatic Ligament, much shorter and smaller 
than the preceding, is thin, triangular in form, attached by its apex to the spine 
of the ischium, and internally, by its broad base, to the lateral margin of the sacrum 
and coccyx, anterior to the attachment of the great sacro-sciatic ligament, with 
which its fibres are intermingled. 
It is in relation anteriorly with the Coccygeus muscle; posteriorly, it is covered 
by the posterior ligament and crossed by the internal pudic vessels and nerve. Its 
superior border forms the lower boundary of the great sacro-sciatic foramen; its 
inferior border, part of the lesser sacro-sciatic foramen. 
These two ligaments convert the sacro-sciatic notches into foramina. The 
superior or great sacro-sciatic foramen is bounded in front and above by the poste- 
rior border of the os innominatum, behind by the great sacro-sciatic ligament, and 
below by the lesser ligament. It is partially filled up, in the recent state, by the 
Pyriformis muscle, which passes through it. Above this muscle the gluteal vessels 
and superior gluteal nerve emerge from the pelvis, and below it the ischiatic ves- 
sels and nerves, the internal pudic vessels and nerve, and the muscular branches 
from the sacral plexus. The inferior or lesser sacro-sciatic foramen is bounded in 
front by the tuber ischii, above by the spine and lesser ligament, behind by the 
greater ligament. It transmits the tendon of the Obturator internus muscle, its 
nerve, and the internal pudic vessels and nerve. 
3. Articulation of the Sacrum and Coccyx. 
This articulation is an amphiarthroclial joint formed between the oval surface 
on the apex of the sacrum and the base of the coccyx. It is analogous to the 
joints between the bodies of the vertebrae, and is connected by similar ligaments. 
They are the 
Anterior Sacro-coccygeal. 
Posterior Sacro-coccygeal. 
Lateral Sacro-coccygeal. 
Interposed Fibro-cartilage. OF THE PELVIS. 
321 
The Anterior Sacro-coccygeal Ligament consists of a few irregular fibres 
which descend from the anterior surface of the sacrum to the front of the coccyx, 
becoming blended with the periosteum. 
The Posterior Sacro-coccygeal Ligament is a flat band of ligamentous fibres, 
of a pearly tint, which arises from the margin of the lower orifice of the sacral canal, 
and descends to be inserted into the posterior surface of the coccyx. This ligament 
completes the lower and back part of the sacral canal. Its superficial fibres are 
much longer than the deep-seated. This ligament is in relation, behind, with the 
Gluteus maximus. 
The Lateral Sacro-coccygeal Ligaments are ligamentous bands which pass 
from the cornua of the last sacral vertebra to the cornua of the first piece of the 
coccyx. 
A fibro-cartilage is interposed between the contiguous surface of the sacrum 
and coccyx; it differs from that interposed between the bodies of the vertebrae in 
being thinner and its central part more firm in texture. It is somewhat thicker in 
front and behind than at the sides. Occasionally, a synovial membrane is found 
when the coccyx is freely movable, which is more especially the case during 
pregnancy. 
The different segments of the coccyx are connected together by an extension 
downward of the anterior and posterior sacro-coccygeal ligaments, a thin annular 
disk of fibro-cartilage being interposed between each of the bones. In the adult 
male all the pieces become ossified, but in the female this does not commonly 
occur until a later period of life. The separate segments of the coccyx are first 
united, and at a more advanced age the joint between the sacrum and coccyx is 
obliterated. 
Actions.-The movements which take place between the sacrum and coccyx, 
and between the different pieces of the latter bone, are slightly forward and back- 
ward ; they are very limited. Their extent increases during pregnancy. 
4. Articulation of the Pubes (Fig. 249). 
The articulation between the pubic bones is an amphiarthrodial joint, formed 
by the junction of the two oval articular surfaces of the ossa pubis. The articular 
surface has been described above under the name of symphysis, and the same name 
is given to the joint. The ligaments of this articulation are the 
Anterior Pubic. 
Superior Pubic. 
Posterior Pubic. 
Subpubic. 
Interposed Fibro-cartilage. 
The Anterior Pubic Ligament consists of several superimposed layers which 
pass across the front of the articulation. The superficial fibres pass obliquely from 
one bone to the other, decussating and forming an interlacement with the fibres of 
the aponeurosis of the External oblique muscle. The deep fibres pass transversely 
across the symphysis and are blended with the fibro-cartilage. 
The Posterior Pubic Ligament consists of a few thin, scattered fibres which 
unite the two pubic bones posteriorly. 
The Superior Pubic Ligament is a band of fibres which connect together the 
two pubic bones superiorly. 
The Subpubic Ligament is a thick, triangular arch of ligamentous fibres con- 
necting together the two pubic bones below and forming the upper boundary of the 
pubic arch. Above it is blended with the interarticular fibro-cartilage, laterally 
with the rami of the pubes. Its fibres are of a yellowish color, closely connected, 
and have an arched direction. 
The Interposed Fibro-cartilage consists of two oval-shaped plates, one cover- 
ing the surface of each symphysis pubis. They vary in thickness in different sub- 
jects, and project somewhat beyond the level of the bones, especially behind. The 
outer surface of each plate is firmly connected to the bone by a series of nipple-like 322 
ARTICULATIONS. 
processes which accurately fit within corresponding depressions on the osseous sur- 
face. Their opposed surfaces are connected in the greater part of their extent by 
an intermediate elastic fibrous 
tissue, and by their circumfer- 
ence to the various ligaments 
surrounding the joint. An in- 
terspace is left between the 
plates at the upper and back 
part of the articulation, where 
the fibrous tissue is deficient, 
and the surface of the fibro- 
cartilage is lined by epithelium. 
This space is found at all periods 
of life, both in the male and fe- 
male ; but it is larger in the lat- 
ter, especially during pregnancy 
and after parturition. It is most 
frequently limited to the upper 
and back part of the joint, but 
it occasionally reaches to the 
front, and may extend the en- 
tire length of the cartilage. 
This structure may be easily demonstrated by making a vertical section of the sym- 
physis pubis near its posterior surface. 
The Obturator Ligament is more properly regarded as analogous to the mus- 
cular fasciae, with which it will therefore be described. 
Two Fibro-Cartilaginousplates 
Intermediate elastic tissue 
Synovial cavity at upper & hack part I j 
Fig. 249. 
Vertical Section of the Symphysis Pubis, made near its posterior 
surface. 
ARTICULATIONS OF THE UPPER EXTREMITY. 
The articulations of the Upper Extremity may be arranged in the following 
groups: I. Sterno-clavicular articulation. II. Acromio-clavicular articulation. 
III. Ligaments of the Scapula. IV. Shoulder-joint. V. Elbow-joint. VI. 
Radio-ulnar articulations. VII. Wrist-joint. VIII. Articulations of the Carpal 
bones. IX. Carpo-metacarpal articulations. X. Metacarpo-phalangeal articula- 
tions. XI. Articulations of the Phalanges. 
I. Sterno-clavicular Articulation (Fig. 250). 
The Sterno-clavicular [Articulation] is regarded by most anatomists as an 
arthrodial joint, but Cruveilhier considers it to be an articulation by reciprocal 
reception. Probably the former opinion is the correct one, the varied movements 
which the joint enjoys being due to the imposition of an interarticular fibro-carti- 
lage between the joint surfaces. The parts entering into its formation are the 
sternal end of the clavicle, the upper and lateral part of the first piece of the 
sternum, and the cartilage of the first rib. The articular surface of the clavicle 
is much largei' than that of the sternum, and invested with a layer of cartilage1 
which is considerably thicker than that on the latter bone. The ligaments of this 
joint are the 
Anterior Sterno-clavicular. 
Posterior Sterno-clavicular. 
Interclavicular. 
Costo-clavicular (rhomboid). 
Interarticular Fibro-cartilage. 
The Anterior Sterno-clavicular Ligament is a broad band of fibres which 
covers the anterior surface of the articulation, being attached above to the upper 
and front part of the inner extremity of the clavicle, and, passing obliquely down- 
1 According to Bruch, the sternal end of the clavicle is covered by a tissue which is rather fibrous 
than cartilaginous in structure. STERNO-CLAVICULAR ARTICULATION. 
323 
ward and inward, is attached below to the upper and front part of the first piece 
of the sternum. This ligament is covered in front by the sternal portion of the 
Sterno-cleido-mastoid and the integument; behind, it is in relation with the inter- 
articular fibro-cartilage and the two synovial membranes. 
The Posterior Sterno-clavicular Ligament is a similar band of fibres which 
covers the posterior surface of the articulation, being attached above to the upper 
Fig. 250. 
Sterno-clavicular Articulation, anterior view. 
and back part of the inner extremity of the clavicle, and which, passing obliquely 
downward and inward, is attached below to the upper and back part of the ster- 
num. It is in relation in front with the interarticular fibro-cartilage and synovial 
membranes; behind, with the Sterno-hyoid and Sterno-thyroid muscles. 
The Interclavicular Ligament is a flattened band which varies considerably 
in form and size in different individuals; it passes in a curved direction from the 
upper part of the inner extremity of one clavicle to the other, and is closely 
attached to the upper margin of the sternum. It is in relation in front with the 
integument; behind, with the Sterno-thyroid muscles. 
The Costo-clavicular Ligament (rhomboid) is short, flat, and strong: it is 
of a rhomboid form, attached below to the upper and inner part of the cartilage of 
the first rib : it ascends obliquely backward and outward, and is attached above to 
the rhomboid depression on the under surface of the clavicle. It is in relation in 
front with the tendon of origin of the Subclavius; behind, with the subclavian 
vein. 
The Interarticular Fibro-cartilage is a flat and nearly circular disk interposed 
between the articulating surfaces of the sternum and clavicle. It is attached above 
to the upper and posterior border of the clavicle, below to the cartilage of the first 
rib at its junction with the sternum, and by its circumference to the anterior and 
posterior sterno-clavicular ligaments. It is thicker at the circumference, especially 
its upper and back part, than at its centre or below. It divides the joint into two 
cavities, each of which is furnished with a separate synovial membrane; when the 
fibro-cartilage is perforated, which not unfrequently occurs, the synovial membranes 
communicate. 
Of the two synovial membranes found in this articulation, one is reflected 
from the sternal end of the clavicle over the adjacent surface of the fibro-cartilage 
and cartilage of the first rib ; the other is placed between the articular surface of 
the sternum and adjacent surface of the fibro-cartilage; the latter is the more loose 
of the two. They seldom contain much synovia. 
Actions.-This articulation is the centre of the movements of the shoulder, and 
admits of a limited amount of motion in nearly every direction-upward, downward, 324 
ARTICULATIONS. 
backward, forward, as well as circumduction. " The movements attendant on ele- 
vation and depression of the shoulder take place between the clavicle and the inter- 
articular ligament, the bone rotating upon the ligament on an axis drawn from before 
backward through its own articular facet. When the shoulder is moved forward 
and backward, the clavicle, with the interarticular ligament, rolls to and fro on 
the articular surface of the sternum, revolving, with a slightly sliding movement, 
round an axis drawn nearly vertically through the sternum. In the circumduction 
of the shoulder, which is compounded of these two movements, the clavicle revolves 
upon the interarticular cartilage, and the latter, with the clavicle, rolls upon the 
sternum."1 
II. Acromio-clavicular Articulation (Fig. 251). 
The Acromio-clavicular is an arthrodial joint formed between the outer 
extremity of the clavicle and the upper edge of the acromion process of the 
scapula. Its ligaments are the 
Superior Acromio-clavicular. 
Inferior Acromio-clavicular. 
Trapezoid 
and 
Conoid. 
Coraco-clavicular 
Interarticular Fibro-cartilage. 
The Superior Acromio-clavicular Ligament is a broad band of a quadrilat- 
eral form which covers the superior part of the articulation, extending between the 
upper part of the outer end of the clavicle and the adjoining part of the upper sur- 
face of the acromion. It is composed of parallel fibres which interlace with the 
aponeurosis of the Trapezius and Deltoid muscles; below it is in contact with the 
interarticular fibro-cartilage (when it exists) and the synovial membranes. 
The Inferior Acromio-clavicular Ligament, somewhat thinner than the pre- 
ceding, covers the under part of the articulation, and is attached to the adjoining 
surfaces of the two bones. It is in relation above with the interarticular fibro-car- 
tilage (when it exists) and the synovial membranes; below, with the tendon of the 
Supraspinatus. These two ligaments are continuous with each other in front and 
behind, and form a complete capsule round the joint. 
The Coraco-clavicular Ligament serves to connect the clavicle with the cora- 
coid process of the scapula. It does not properly belong to this articulation, but as 
it forms a most efficient.means in retaining the clavicle in contact with the acromial 
process, it is usually described with it. It consists of two fasciculi, called the trape- 
zoid and conoid ligaments. 
The Trapezoid Ligament, the anterior and external fasciculus, is broad, thin, 
and quadrilateral: it is placed obliquely between the coracoid process and the clav- 
icle. It is attached below to the upper surface of the coracoid process; above, to 
the oblique line on the under surface of the clavicle. Its anterior border is free; 
its posterior border is joined with the conoid ligament, the two forming by their 
junction a projecting angle. 
The Conoid Ligament, the posterior and internal fasciculus, is a dense band of 
fibres conical in form, the base being turned upward, the summit downward. It 
is attached by its apex to a rough impression at the base of the coracoid process, 
internal to the preceding; above, by its expanded base, to the conoid tubercle on 
the under surface of the clavicle, and to a line proceeding internally from it for 
half an inch. These ligaments are in relation in front with the Subclavius; 
behind, with the Trapezius: they serve to limit rotation of the scapula forward 
and backward. 
The Interarticular Fibro-cartilage is most frequently absent in this articula- 
tion. When it exists it generally only partially separates the articular surfaces and 
1 Humphry, On the Human Skeleton, p. 402. ACROMIO-CLAVICULAR ARTICULATION. 
325 
occupies the upper part of the articulation. More rarely it completely separates the 
joint into two cavities. 
There are two synovial membranes when a complete interarticular cartilage 
exists; more frequently there is only one synovial membrane. 
Actions.-The movements of this articulation are of two kinds: 1, A gliding 
motion of the articular end of the clavicle on the acromion; 2, rotation of the 
Fig. 251. 
The Left Shoulder-joint: Scapulo-clavicular Articulations and Proper Ligaments of Scapula. 
scapula forward and backward upon the clavicle, the extent of this rotation being 
limited by the two portions of the coraco-clavicular ligament. 
The scapulo-clavicular joint has important functions in the movements of the 
upper extremity. It has been well pointed out by Prof. Humphry that if there 
had been no joint between the clavicle and scapula the circular movement of the 
scapula on the ribs (as in throwing both shoulders backward or forward) would 
have been attended with a greater alteration in the direction of the shoulder than 
is consistent with the free use of the arm in such positions, and it would have been 
impossible to give a blow straight forward with the full force of the arm-that is to 
say, with the combined force of the scapula, arm, and forearm. "This joint," as 
he happily says, "is so adjusted as to enable either bone to turn in a hinge-like 
manner upon a- vertical axis drawn through the other, and it permits the surfaces 
of the scapula, like the baskets in a roundabout swing, to look the same way in 
every position, or nearly so." Again, when the whole arch formed by the clavicle 
and scapula rises and falls (in elevation or depression of the shoulders) the joint 
between these two bones enables the scapula still to maintain its lower part in con- 
tact with the ribs. 326 
ARTICULATIONS. 
IH. Proper Ligaments of the Scapula (Fig. 251). 
The proper ligaments of the scapula are the 
Coraco-acromial. 
Transverse. 
The Coraco-acromial Ligament is a broad, thin, flat band of a triangular 
shape extended transversely above the upper part of the shoulder-joint, between 
the coracoid and acromial processes. It is attached by its apex to the summit of 
the acromion just in front of the articular surface for the clavicle'; and by its broad 
base to the whole length of the outer border of the coracoid process. Its posterior 
fibres are directed obliquely backward and inward, its anterior fibres transversely 
inward. This ligament completes the vault formed by the coracoid and acromion 
processes for the protection of the head of the humerus. It is in relation above 
with the clavicle and under surface of the Deltoid; below, with the tendon of the 
Supraspinatus muscle, a bursa being interposed. Its anterior border is continuous 
with a dense cellular lamina that passes beneath the Deltoid upon the tendons of 
the Supra- and Infra-spinatus muscles. 
The Transverse or Coracoid (suprascapular) Ligament converts the supra- 
scapular notch into a foramen. It is a thin and flat fasciculus, narrower at the 
middle than at the extremities, attached by one end to the base of the coracoid pro- 
cess, and by the other to the inner extremity of the scapular notch. The supra- 
scapular nerve passes through the foramen ; the suprascapular vessels above it. [It 
is sometimes wholly ossified.] 
IV". Shoulder-joint (Fig. 251). 
The Shoulder is an enarthrodial or ball-and-socket joint. The bones entering 
into its formation are the large globular head of the humerus, received into the 
shallow glenoid cavity of the scapula-an arrangement which permits of very con- 
siderable movement, whilst the joint itself is protected against displacement by the 
tendons which surround it and by atmospheric pressure. The ligaments have nothing 
directly to do with maintaining the joint surfaces in apposition; if they alone remain, 
the humerus can be separated to a considerable extent from the glenoid cavity; their 
use, therefore, is to limit the amount of movement. [This separation of the humerus 
from the glenoid cavity is at its maximum when the humerus is halfway between ab- 
and rtc?-duction, and diminishes as we approach either extreme. In extreme ab- or 
«cZ-duction the lower or upper fibres of the capsular ligament respectively are made 
tense and hold the bones together.] Above, the joint is protected by an arched vault 
formed by the under surface of the coracoid and acromion processes and the coraco- 
aciomial ligament. The articular surfaces are covered by a layer of cartilage: that 
on the head of the humerus is thicker at the centre than at the circumference, the 
reverse being the case in the glenoid cavity. The ligaments of the shoulder are the 
Capsular. 
Glenoid.1 
Coraco-humeral. 
The Capsular Ligament completely encircles the articulation, being attached 
above to the circumference of the glenoid cavity beyond the glenoid ligament, below 
to the anatomical neck of the humerus, approaching nearer to the articular cartilage 
above than in the rest of its extent. It is thicker above than below, remarkably 
loose and lax, and much larger and longer than is necessary to keep the bones in 
contact, allowing them to be separated from each other more than an inch-an evi- 
dent provision for that extreme freedom of movement which is peculiar to this artic- 
ulation. Its external surface is strengthened above by the Supraspinatus, below by 
the long head of the Triceps, externally by the tendons of the Infraspinatus and 
Teres minor, and internally by the tendon of the Subscapularis. The capsular liga- 
1 The long tendon of origin of the Biceps muscle also acts as one of the ligaments of this joint. 
See the observations on p. 301 on the function of the muscles passing over more than one joint. SHO ULDER-JOINT. 
327 
ment usually presents three openings: one at its inner side, below the coracoid pro- 
cess, partially filled up by the tendon of the Subscapularis; it establishes a com- 
munication between the synovial membrane of the joint and a bursa beneath the 
tendon of that muscle. The second, which is not constant, is at the outer part, 
where a communication sometimes exists between the joint and a bursal sac belong- 
ing to the Infraspinatus muscle. The third is seen in the lower border of the liga- 
ment, between the two tuberosities, for the passage of the long tendon of the Biceps 
muscle. 
The capsular ligament is strengthened by supplemental bands in addition to the 
Coraco-humeral or accessory ligament, which is usually described as a distinct struc- 
ture. Some of these are situated on the inner side of the joint, and pass from the 
inner edge of the glenoid cavity to the lower part of the lesser tubercle of the hu- 
merus. Others are situated at the lower part of the joint, and pass from the under 
edge of the glenoid cavity to the under part of the neck of the humerus. 
The Coraco-humeral or Accessory Ligament is a broad band which strength- 
ens the upper part of the capsular ligament. It arises from the outer border of the 
coracoid process, and passes obliquely downward and outward to the front of the 
great tuberosity of the humerus, being blended with the tendon of the Supraspina- 
tus muscle. This ligament is intimately united to the capsular in the greater part 
of its extent. Some of the fibres of this ligament are prolonged into the joint 
through the opening in the capsular ligament for the tendon of the Biceps, and are 
inserted into the inner margin of the upper end of the bicipital groove. They have 
been called the gleno-humeral (Flood's) ligament, and are supposed to correspond 
with the ligamentum teres in the hip-joint. 
The Glenoid Ligament is a fibro-cartilaginous rim attached round the margin 
of the glenoid cavity. It is triangular on section, the thickest portion being fixed 
to the circumference of the cavity, the free edge being thin and sharp. It is con- 
tinuous above with the long tendon of the Biceps muscle, which bifurcates at the 
upper part of the cavity into two fasciculi encircling the margin of the glenoid cavity 
and uniting at its lower part. This ligament deepens the cavity for articulation and 
protects the edges of the bone. It is lined by the synovial membrane. 
The synovial membrane is reflected from the margin of the glenoid cavity over 
[Fig. 252. 
[Fig. 253. 
Vertical Sections through the Shoulder-joint, the arm being vertical (Fig. 252) and horizontal (Fig. 253): ssp, 
tendon of supraspinatus; d, deltoid; b, tendon of long bead of biceps; ssc, subscapularis; t, tendon of long 
head of triceps; *, posterior circumflex artery and circumflex nerve; tm, teres major (Henle).] 
the fibro-cartilaginous rim surrounding it; it is then reflected over the internal sur- 
face of the capsular ligament, covers the lower part and sides of the neck of the 
humerus, and is continued a short distance over the cartilage covering the head of 
the bone. The long tendon of the Biceps muscle which passes through the capsular 
ligament is enclosed in a tubular sheath of synovial membrane, which is reflected 328 
ARTICULA TIONS. 
upon it at the point where it perforates the capsule, and is continued around it as 
far as the summit of the glenoid cavity. The tendon of the Biceps is thus enabled 
to traverse the articulation, but it is not contained in the interior of the synovial 
cavity. The synovial membrane communicates with a large bursal sac beneath the 
tendon of the Subscapularis by an opening at the inner side of the capsular liga- 
ment ; it also occasionally communicates with another bursal sac beneath the tendon 
of the Infraspinatus through an orifice at its outer part. A third bursal sac, which 
does not communicate with the joint, is placed between the under surface of the 
Deltoid and the outer surface of the capsule. 
The 'Muscles in relation with the joint are-above, the Supraspinatus; below, 
the long head of the Triceps; internally, the Subscapularis; externally, the Infra- 
spinatus and Teres minor; within, the long tendon of the Biceps. The Deltoid is 
placed most externally, and covers the articulation on its outer side as well as in 
front and behind. 
The Arteries supplying the joint are articular branches of the anterior and pos- 
terior circumflex and suprascapular. 
The Nerves are derived from the circumflex and suprascapular. 
Actions.-The shoulder-joint is capable of movement in every direction, forward, 
backward, abduction, adduction, circumduction, and rotation. The humerus is drawn 
forward by the Pectoralis major, anterior fibres of the Deltoid, Coraco-brachialis, 
and by the Biceps when the elbow is fixed; backward, by the Latissimus dorsi, 
Teres major, posterior fibres of the Deltoid, and by the Triceps when the elbow is 
fixed; it is abducted (elevated) by the Deltoid and Supraspinatus; it is adducted 
(depressed) by the Subscapularis, Pectoralis major, Latissimus dorsi, and Teres 
major; it is rotated outward by the Infraspinatus and Teres minor; and it is 
rotated inward by the Subscapularis, Latissimus dorsi, and Teres major. 
The most striking peculiarities in this joint are-1, The large size of the head 
of the humerus in comparison with the depth of the glenoid cavity, even when sup- 
plemented by the glenoid ligament; 2, the looseness of the capsule of-the joint; 
3, the intimate connection of the capsule with the muscles attached to the head of 
the humerus; 4, the peculiar relation of the biceps tendon to the joint. 
It is in consequence of the relative size of the two articular surfaces that the 
joint enjoys such free movement in every possible direction. When these move- 
ments of the arm are arrested in the shoulder-joint by the contact of the bony sur- 
faces and by the tension of the corresponding fibres of the capsule, together with 
that of the muscles acting as accessory ligaments, they can be carried considerably 
farther by the movements of the scapula, involving, of course, motion at the acromio- 
and sterno-clavicular joints. These joints are therefore to be regarded as accessory 
structures to the shoulder-joint.1 The extent of these movements of the scapula is 
very considerable, especially in extreme elevation of the arm; which movement is 
best accomplished when the arm is thrown somewhat forward, since the articular 
surface of the humerus is broader in the middle than at either end, especially the 
lower, so that the range of elevation directly forward is less, and that directly back- 
ward still more restricted. The great width of the central portion of the humeral 
head also allows of very free horizontal movement when the arm is raised to a right 
angle; in which movement the arch formed by the acromion, the coracoid process, 
and the coraco-acromial ligament constitutes a sort of supplemental articular cavity 
for the head of the bone. 
The looseness of the capsule is so great that the arm will fall about an inch 
from the scapula when the muscles are dissected from the capsular ligament and 
an opening made in it to remove the atmospheric pressure. The movements of 
the joint, therefore, are not regulated by the capsule so much as by the surround- 
ing muscles and by the pressure of the atmosphere-an arrangement which " ren- 
ders the movements of the joint much more easy than they would otherwise have 
been, and permits a swinging, pendulum-like vibration of the limb when the mus- 
cles are at rest" (Humphry). The fact also that in all ordinary positions of the 
1 See pp. 322, 324. ELBOW-JOINT. 
329 
joint the capsule is not put on the stretch enables the arm to move freely in all 
directions. Extreme movements are checked by the tension of appropriate portions 
of the capsule, as well as by the interlocking of the bones. Thus it is said that 
" abduction is checked by the contact of the great tuberosity with the upper edge 
of the glenoid cavity; adduction, by the tension of the coraco-humeral ligaments" 
(Beaunis et Bouchard). 
[Nothing is more striking in the anatomy of the back, when studied in the 
living model, than this mobility of the scapula and its influence on the form of the 
trunk. Shrugging one shoulder shows, by comparison, the vertical movement; when 
the arm is raised to about thirty degrees the scapula already begins to take part in 
the movement, and by the time the arms are well thrown forward or upward the dis- 
tance between the two inferior angles has been increased by as much as ten or twelve 
inches, the inferior angles being displaced to the sides of the thorax, and the direction 
of the vertebral borders and the spine of the scapula is entirely changed, while the 
back, which formerly showed the rugged outlines of the scapula and its muscles, is flat- 
tened and almost smooth; leaning the weight on one arm or on a crutch shows its 
passive mobility by pressure and the disparity of the two sides to great advantage. In 
Michael Angelo's statues on Julian de Medici's tomb in Florence, Sir Charles Bell 
has noticed the correctness of the anatomy on this point. Mr. Wagstaffe (Human 
Osteology} has called attention to the great advantage that this mobility of the 
scapula gives in increasing the usefulness of the arm by its acting as a " shifting 
fulcrum," and well compares this to the advantage given the modern oarsman by 
the " sliding seat." 
The mobility of the scapula is of the greatest use in ankylosis of the shoulder- 
joint, diminishing to a large extent the loss of usefulness resulting from the immo- 
bility. Whenever there is unequal prominence of the scapulae the spine should be 
examined for curvature.] 
The intimate union of the tendons of the four short muscles with the capsule 
converts these muscles into elastic and spontaneously acting ligaments of the joint, 
and it is regarded as being also intended to prevent the folds into which all portions 
of the capsule would alternately fall in the varying positions of the joint from being 
driven between the bones by the pressure of the atmosphere. 
The peculiar relations of the Biceps tendon to the shoulder-joint appear to sub- 
serve various purposes. In the first place, by its connection with both the shoulder 
and elbow the muscle harmonizes the action of the two joints and acts as an elastic 
ligament in all positions, in the manner previously adverted to.1 Next it strength- 
ens the upper part of the articular cavity, and prevents the head of the humerus 
from being pressed up against the acromion process when the deltoid contracts, 
instead of forming the centre of motion in the glenoid cavity. By its passage 
along the bicipital groove it assists in rendering the head of the humerus steady 
in the various movements of the arm and forearm. To these offices Prof. Humphry 
adds that " it assists the Supra- and Infra-spinatus muscles to cause the head of the 
humerus to revolve in the glenoid cavity when the arm is raised from the side, and 
that it holds the head of the humerus firmly in contact with the glenoid cavity, and 
prevents its slipping over the lower edge of the cavity, or being displaced by the 
action of the Latissimus dorsi and Pectoralis major when the arm is raised from the 
side, as in climbing and many other movements." 
V. Elbow-joint. 
The Elbow is a ginglymus or hinge-joint. The bones entering into its forma- 
tion are the trochlear surface of the humerus, which is received in the greater sig- 
moid cavity of the ulna, and admits of the movements peculiar to this joint, those 
of flexion and extension, whilst the cup-shaped depression on the head of the radius 
articulates with the lesser or radial head of the humerus, and the circumference of 
the head of the radius with the lesser sigmoid cavity of the idna, allowing of the 
1 See p. 301. 330 
ARTICULA TIONS. 
movement of rotation of the radius on the ulna, the chief action of the superior 
radio-ulnar articulation. [For the angle formed at the elbow between the arm and 
forearm, see p. 242.] The articular surfaces are covered with a thin layer of car- 
tilage and connected together by the following ligaments: 
Anterior. 
Posterior. 
Internal Lateral. 
External Lateral. 
The orbicular ligament of the upper radio-ulnar articulation must also be 
reckoned among the ligaments of the 
elbow. 
The Anterior Ligament (Fig. 254) is 
a broad and thin fibrous layer which covers 
the anterior surface of the joint. It is at- 
tached to the front of the internal condyle 
and to the front of the humerus immediately 
above the coronoid fossa; below, to the an- 
terior surface of the coronoid process of the 
ulna and orbicular ligament, being contin- 
uous on each side with the lateral ligaments. 
Its superficial oblique fibres pass from the 
inner condyle of the humerus outward to the 
orbicular ligament. The middle fibres, ver- 
tical in direction, pass from the upper part 
of the coronoid depression, and become partly 
blended with the preceding, but mainly in- 
serted into the anterior surface of the coro- 
noid process. A third or transverse set in- 
tersects these at right angles. This ligament 
is in relation in front with the Brachialis an- 
ticus; behind with the synovial membrane. 
The Posterior Ligament (Fig. 255) is a 
thin and loose membranous fold attached 
above to the lower end of the humerus, 
immediately above the olecranon fossa; be- 
low to the margin of the olecranon. The 
superficial or transverse fibres pass between 
the adjacent margins of the olecranon fossa. 
The deeper portion consists of vertical fibres 
which pass from the upper part of the ole- 
cranon fossa to the margin of the olecranon. 
This ligament is in relation behind with the 
tendon of the Triceps and the Anconeus; in 
front with the synovial membrane. 
The Internal Lateral Ligament (Fig. 254) is a thick triangular band con- 
sisting of two distinct portions, an anterior and a posterior. The anterior portion, 
directed obliquely forward, is attached above, by its apex, to the front part of the 
internal condyle of the humerus, and below, by its broad base, to the inner margin 
of the coronoid process. The posterior portion, also of triangular form, is attached 
above, by its apex, to the lower and back part of the internal condyle; below to 
the inner margin of the olecranon. This ligament is in relation internally with the 
Triceps and Flexor carpi ulnaris muscles and the ulnar nerve. 
The External Lateral Ligament (Fig. 255) is a short and narrow fibrous fas- 
ciculus less distinct than the internal, attached above to a depression below the 
external condyle of the humerus; below to the orbicular ligament, some of its most 
posterior fibres passing over that ligament to be inserted into the outer margin of 
the ulna. This ligament is intimately blended with the tendon of origin of the 
Supinator brevis muscle. 
Fig. 254. 
Left Elbow-joint, showing anterior and internal 
ligaments. ELBOW-JOINT 
331 
The synovial membrane is very extensive. It covers the margin of the 
articular surface of the humerus and lines the 
coronoid and olecranon fossse on that bone; from 
these points it is reflected over the anterior, pos- 
terior, and lateral ligaments, and forms a pouch 
between the lesser sigmoid cavity, the internal 
surface of the orbicular ligament, and the circum- 
ference of the head of the radius. 
The Muscles in relation with the j oint are-in 
front, the Brachialis anticus; behind, the Triceps 
and Anconeus; externally, the Supinator brevis 
and the common tendon of origin of the Extensor 
muscles; internally, the common tendon of origin 
of the Flexor muscles and the Flexor carpi ulna- 
ris with the ulnar nerve. 
The Arteries supplying the joint are derived 
from the communicating branches between the 
superior profunda, inferior profunda, and anasto- 
motic branches of the brachial with the anterior, 
posterior, and interosseous recurrent branches of 
the ulnar and the recurrent branch of the radial. 
These vessels form a complete chain of inoscula- 
tion around the joint. 
The Nerves are derived from the ulnar as it 
passes between the internal condyle and the ole- 
cranon, and a few filaments from the musculo- 
cutaneous. 
Actions.-The elbow-joint comprises three 
different portions-viz. the joint between the 
ulna and humerus, that between the head of 
the radius and the humerus, and the superior 
radio-ulnar articulation, described below. All 
these articular surfaces are invested by a com- 
mon synovial membrane, and the movements of the whole joint should be studied 
Fig. 255. 
Left Elbow-joint, showing posterior and 
external ligaments. 
[Fig. 256. 
[Fig. 257. 
CAPSULAR 
LIGT. '*< 
Sections through the Elbow-joint in extension (Fig. 256) and flexion (Fig. 257): b, tendon of biceps; c synovial 
bursa over olecranon (Henle).] ' ' 
together. The combination of the movements of flexion and extension of the fore- 332 
ARTICULA TIONS. 
arm with those of pronation and supination of the hand, which is ensured by the two 
being performed at the same joint, is essential to the accuracy of the various minute 
movements of the hand. 
The portion of the joint between the ulna and humerus is a simple hinge-joint, 
and allows of movements of flexion and extension only. The shape of the trochlear 
surface of the humerus, with its prominences and depressions accurately adapted to 
the opposing surfaces of the olecranon, prevents any lateral movement. In the ordi- 
nary position assumed by the humerus when resting on the prominent internal con- 
dyle this direct movement of flexion carries the hand inward toward the chest and 
mouth. Flexion is produced by the action of the Biceps and Brachialis anticus, 
assisted by the muscles arising from the internal condyle of the humerus and the 
Supinator longus'; extension, by the Triceps and Anconeus, assisted by the extensors 
of the wrist and by the Extensor communis digitorum and Extensor minimi digiti. 
The joint between the head of the radius and the capitellum or radial head of 
the humerus is an arthrodial joint. The bony surfaces would of themselves consti- 
tute an enarthrosis, and allow of movement in all directions, were it not for the 
orbicular ligament by which the head of the radius is bound down firmly to the 
sigmoid cavity of the ulna, and which prevents any separation of the two bones 
laterally. It is to the same ligament that the head of the radius owes its security 
from dislocation, which would otherwise constantly occur as a consequence of the 
shallowness of the cup-like surface on the head of the radius. In fact, but for this 
ligament the tendon of the biceps would be liable to pull the head of the radius out 
of the joint.1 In complete extension the head of the radius glides so far back on 
the outer condyle that its edge is plainly felt at the back of the joint. 
In combination with any position of flexion or extension the head of the radius 
can be rotated in the upper radio-ulnar joint, carrying the hand with it. The hand 
is articulated to the lower surface of the radius only, and the concave or sigmoid 
surface on the lower end of the radius travels round the lower end of the ulna. 
The latter bone is excluded from the wrist-joint (as will be seen in the sequel) by 
the triangular fibro-cartilage. Thus, rotation of the head of the radius round an 
axis which passes through the external condyle of the humerus imparts circular 
movement to the hand through a very considerable arc. If it is necessary to turn 
the hand upward and downward without changing its place (as in using a cork- 
screw), this circular movement is obviated by rapid instinctive compensating 
changes in the position of the elbow. 
[Mr. Henry Morris {Anatomy of the Joints') has called attention to the fact that 
the humerus and ulna often act as one rigid rod, which he calls the " humero-ulnar 
shaft." By its rotation at the shoulder it materially adds to the range of rotation 
of the hand, which would otherwise be limited strictly to that of the radius on the 
ulna. Besides this, as he notes especially, it has been entirely overlooked that this 
"humero-ulnar shaft" when the hand is fixed also rotates as a whole on the head 
of the radius as a centre, thus adding to the mobility of the shoulder. This action 
is well seen in vaulting, or in walking round a chair while one hand is firmly fixed 
on its back. The muscles which rotate the humerus will also rotate the ulnar por- 
tion of this humero-ulnar shaft; and some of the muscles which rotate the radius 
will, when the hand is fixed, have the reverse action on the ulna, and through it on 
the humerus.] 
VI. Radio-ulnar Articulations 
The articulation of the radius with the ulna is effected by ligaments which con- 
nect together both extremities as well as the shafts of these bones. They may, 
consequently, be subdivided into three sets: 1, The superior radio-ulnar, which 
is a portion of the elbow-joint; 2, the middle radio-ulnar; and, 3, the inferior 
radio-ulnar articulations. 
1 Humphry, op. cit., p. 419. RADIO-ULNAR ARTICULATIONS. 
333 
1. Superior Radio-ulnar Articulation. 
This articulation is a lateral ginglymus (diarthrodia rotatoria). The bones enter- 
ing into its formation are the inner side of the circumference of the head of the radius 
rotating within the lesser sigmoid cavity of the ulna. These surfaces are covered with 
cartilage, and invested with a duplicature of synovial membrane continuous with that 
which lines the elbow-joint. Its only ligament is the annular or orbicular. 
The Orbicular Ligament (Fig. 255) is a strong, flat band of ligamentous fibres 
which surrounds the head of the radius and retains it in firm connection with the 
lesser sigmoid cavity of the ulna. It forms about four-fifths of a fibrous ring 
attached by each end to the extremities of the lesser sigmoid cavity, and is broader 
at the upper part of its circumference than below, by which means the head of the 
radius is more securely held in its position. Its owter surface is strengthened by 
the external lateral ligament of the elbow, and affords origin to part of the Supinator 
brevis muscle. Its inner surface is smooth and lined by synovial membrane. 
Actions.-The movement which takes place in this articulation is limited to 
rotation of the head of the radius within the orbicular ligament and upon the lesser 
sigmoid cavity of the ulna, rotation forward being called pronation; rotation back- 
ward, supination. Supination is performed by the Biceps, Supinator brevis, and 
■Supinator longus, assisted to a slight extent by the Extensor muscles of the thumb. 
Pronation is performed by the Pronator radii teres and the Pronator quadratus. 
2. Middle Radio-ulnar Articulation. 
The interval between the shafts of the radius and ulna is occupied by two liga- 
ments : 
Oblique. 
Interosseous. 
The Oblique or Round Ligament (Fig. 254) is a small, round fibrous cord 
which extends obliquely downward and outward from the tubercle of the ulna at 
the base of the coronoid process to the radius a little below the bicipital tuberosity. 
Its fibres run in the opposite direction to those of the interosseous ligament, and it 
appears to be placed as a substitute for it in the upper part of the interosseous inter- 
val. This ligament is sometimes wanting. 
The Interosseous Membrane [which acts as a ligament] is a broad and thin plane 
•of aponeurotic fibres descending obliquely downward and inward from the interosseous 
ridge on the radius to that on the ulna [and so supports the humero-ulnar shaft when 
the weight comes on the hand]. It is deficient above, commencing about an inch 
beneath the tubercle of the radius, is broader in the middle than at either extremity, 
and presents an oval aperture just above its lower margin for the passage of the ante- 
rior interosseous vessels to the back of the forearm. This ligament serves to connect 
the bones and to increase the extent of surface for the attachment of the deep mus- 
cles. Between its upper border and the oblique ligament an interval exists through 
which the posterior interosseous vessels pass. Two or three fibrous bands are occa- 
sionally found on the posterior surface of this membrane which descend obliquely 
from the ulna toward the radius, and which have, consequently, a direction contrary 
to that of the other fibres. It is in relation in front by its upper three-fourths with 
the Flexor longus pollicis on the outer side, and with the Flexor profundus digitorum 
■on the inner, lying upon the interval between which are the anterior interosseous 
vessels and nerve; by its lower fourth, with the Pronator quadratus; behind, with 
the Supinator brevis, Extensor ossis metacarpi pollicis, Extensor primi internodii 
pollicis, Extensor secundi internodii pollicis, Extensor indicis; and, near the wrist, 
with the anterior interosseous artery and posterior interosseous nerve. 
3. Inferior Radio-ulnar Articulation. 
This is a lateral ginglymus (diarthrodia rotatoria) formed by the head of the 
ulna received into the sigmoid cavity at the inner side of the lower end of the radius. 334 
ARTICULATIONS. 
The articular surfaces are covered by a thin layer of cartilage and connected together 
by the following ligaments : 
Anterior Radio-ulnar. 
Posterior Radio-ulnar. 
Triangular Interarticular Fibro-cartilage. 
The Anterior Radio-ulnar Ligament (Fig. 258) is a narrow band of fibres 
extending from the anterior margin of the sigmoid cavity of the radius to the ante- 
rior surface of the head of the ulna. 
The Posterior Radio-ulnar Ligament (Fig. 259) extends between similar 
points on the posterior surface of the articulation. 
The Triangular Fibro-cartilage (Fig. 260, p. 339) is placed transversely 
beneath the head of the ulna, binding the lower end of this bone and radius firmly 
Fig. 258. 
INFERIOR RADIO-ULNAR ARTIC 1 
WRIST-JOINT 
CARPAL ARTIC?? 
CARPO-METACARPAL ARTIC !? 
Ligaments of Wrist and Hand, anterior view. 
together. Its circumference is thicker than its centre, which is thin and occasion- 
ally perforated. It is attached by its apex to a depression which separates the sty- 
loid process of the ulna from the head of that bone, and by its base, which is thin, 
to the prominent edge of the radius, which separates the sigmoid cavity from the 
carpal articulating surface. Its lateral margins are united to the ligaments of the 
wrist-joint. Its upper surface, smooth and concave, articulates with the head of 
the ulna, forming an arthrodial joint; its under surface, also concave and smooth, 
forms part of the wrist-joint and articulates with the cuneiform bone. Both surfaces 
are lined by a synovial membrane-the upper surface by one peculiar to the radio- 
ulnar articulation, the under surface by the synovial membrane of the wrist. 
The synovial membrane (Fig. 260) of this articulation has been called, from 
its extreme looseness, the membrana sacciformis; it extends horizontally inward 
between the head of the ulna and the interarticular fibro-cartilage, and upward 
between the radius and the ulna, forming here a very loose cul-de-sac. [This laxity 
of the synovial membrane is necessary, in consequence of the large range of move- 
ment in pro- and supi-nation.] The quantity of synovia which it contains is usually 
considerable. When the fibro-cartilage is perforated the synovial membrane is con- 
tinuous with that which lines the wrist. RADIO-CARPAL OR WRIST-JOINT. 
335 
Actions.-The arrangement in the inferior radio-ulnar articulation is just the 
reverse of that between the two bones above: motion is limited to rotation of the 
radius round the head of the ulna, rotation forward being termed pronation, rotation 
backward supination. In pronation the sigmoid cavity glides forward on the artic- 
Fig. 259. 
Inferior 
Radio -ulnar Artic 
"Wrist-Tot ht 
CcLrpdl .Arti/Q 
Carp oAfeta carpal 
Artic rr 
Ligaments of Wrist and Hand, posterior view. 
ular edge of the ulna; in supination it rolls in the opposite direction, the extent of 
these movements being limited by the anterior and posterior ligaments. It will thus 
be seen that in pronation and supination of the forearm and hand the radius describes 
a segment of a cone, the axis of which extends from the centre of. the head of the 
radius to the styloid process of the ulna.1 
VII. Radio-carpal or Wrist-joint. 
The Wrist is a condyloid articulation. The parts entering into its formation are 
the lower end of the radius and under surface of the triangular interarticular fibro- 
cartilage, which form together the receiving cavity, consisting of a transversely ellip- 
tical concave surface, and the scaphoid, semilunar, and cuneiform bones, which form 
the condyle. The surface of the radius is subdivided into two parts by a line extend- 
ing from before backward; and these, together with the interarticular cartilage, 
form three facets, one for each carpal bone. The three carpal bones are connected 
together, and form a convex surface which is received into the concavity above 
mentioned. All the bony surfaces of the articulation are covered with cartilage, 
and connected together by the following ligaments: 
1 [The lower end of this axis is rather the centre of the head of the ulna, and if prolonged would 
pass through the ring-finger. "The head of the radius is so disposed in relation to the sigmoid cav- 
ity of the lower extremity that the axis of the former, if prolonged downward, falls upon the centre 
of the circle of which the latter is a segment" (Ward)-a necessity, in fact, if the head of the radius 
is fixed.] 
Until recently it has been almost universally taught that in rotation it is the radius which 
revolves and the ulna which remains at rest. Professor Heiberg of Christiania has, however, come 
to the conclusion that the " rotation of the forearm is due to the combined and complementary move- 
ments of the two bones, both of which rotate." Though this is probably not the case, there is no 
doubt that the lower end of the ulna is not stationary, but undergoes a certain amount of lateral 
movement during the acts of pronation and supination of the forearm. Dr. Cathcart believes that 
this movement takes place principally at the shoulder-joint. (See Journal of Anatomy and Physiology. 
vol. xix. Parts IL, III., and IV.) 336 
ARTICULATIONS. 
External Lateral. 
Internal Lateral. 
Anterior. 
Posterior. 
The External Lateral Ligament (Fig- 258) extends from the 
summit of the styloid process of the radius to the outer side of the scaphoid, some 
■of its fibres being prolonged to the trapezium and annular ligament. 
The Internal Lateral Ligament (ulno-carpaT) is a rounded cord attached, above, 
to the extremity of the styloid process of the ulna, and dividing below into two fas- 
ciculi, which are attached, one to the inner side of the cuneiform bone, the other to 
the pisiform bone and annular ligament. 
The Anterior Ligament is a broad membranous band consisting of three fas- 
ciculi attached, above, to the anterior margin of the lower end of the radius, its 
styloid process, and the ulna; its fibres pass downward and inward to be inserted 
into the palmar surface of the scaphoid, semilunar, and cuneiform bones, some of 
the fibres being continued to the os magnum. In addition to this broad membrane 
there is a distinct rounded fasciculus, superficial to the rest, which passes from the 
base of the styloid process of the ulna to the semilunar and cuneiform bones. This 
ligament is perforated by numerous apertures for the passage of vessels, and is in 
relation, in front, with the tendons of the Flexor profundus digitorum and Flexor 
longus pollicis ; behind, with the synovial membrane of the wrist-joint. [This liga- 
ment has an important bearing in producing the deformity of Colles' fracture, as 
has been shown by Pilcher.1] 
The Posterior Ligament (Fig. 259), less thick and strong than the anterior, is 
attached above to the posterior border of the lower end of the radius; its fibres 
pass obliquely downward and inward to be attached to the dorsal surface of the 
scaphoid, semilunar, and cuneiform bones, being continuous with those of the dor- 
sal carpal ligaments. This ligament is in relation behind with the extensor tendons 
■of the fingers; in front with the synovial membrane of the wrist. 
The synovial membrane (Fig. 260) lines the under surface of the triangular 
interarticular fibro-cartilage above, and is reflected on the inner surface of the 
ligaments just described. 
Relations.-The wrist-joint is covered in front by the flexor, and behind by 
the extensor tendons; it is also in relation with the radial and ulnar arteries. 
The Arteries supplying the joint are the anterior and posterior carpal branches 
of the radial and ulnar, the anterior and posterior interosseous, and some ascending 
branches from the deep palmar arch. 
The Nerves are derived from the ulnar and posterior interosseous. 
Actions.-The movements permitted in this joint are flexion, extension, abduc- 
tion, adduction, and circumduction. It is totally incapable of rotation. Its actions 
will be further studied with those of the carpus, with which they are combined. 
VIII. Articulations of the Carpus. 
These articulations may be subdivided into three sets: 
1. The Articulations of the First Row of Carpal Bones. 
2. The Articulations of the Second Row of Carpal Bones. 
3. The Articulations of the Two Rows with each other. 
1. Articulations of the First Row of Carpal Bones. 
These are arthrodial joints. The articular surfaces are covered with cartilage, 
and connected together by the following ligaments: 
Two Dorsal. 
Two Interosseous. 
Two Palmar. 
The Dorsal Ligaments are placed transversely behind the bones of the first 
row ; they connect the scaphoid and semilunar and the semilunar and cuneiform. 
1 N. Y. Med. Record, July 27, 1878. ARTICULATIONS OF THE CARPUS. 
337 
The Palmar Ligaments connect the scaphoid and semilunar and the semilunar 
and cuneiform bones; they are less strong than the dorsal, and placed very deep 
under the anterior ligament of the wrist. 
The Interosseous Ligaments (Fig. 260) are two narrow bundles of fibrous 
tissue connecting the semilunar bone on one side with the scaphoid, on the other 
with the cuneiform. They are on a level with the superior surfaces of these bones, 
and close the upper part of the interspaces between them. Their upper surfaces 
are smooth, and form with the bones the convex articular surface of the wrist-joint. 
The articulation of the pisiform with the cuneiform is provided with a separate 
synovial membrane protected by a thin capsular ligament. There are also two 
strong fibrous fasciculi, which connect this bone to the unciform and the base of 
the fifth metacarpal bone (Fig. 258). 
2. Articulations of the Second Row of Carpal Bones. 
These are also arthrodial joints. The articular surfaces are covered with carti- 
lage, and connected by the following ligaments : 
Three Dorsal. 
Three Palmar. 
The three Dorsal Ligaments extend transversely from one bone to another on 
the dorsal surface, connecting the trapezium with the trapezoid, the trapezoid with 
the os magnum, and the os magnum with the unciform. 
The three Palmar Ligaments have a similar arrangement on the palmar 
surface. 
The three Interosseous Ligaments, much thicker than those of the first row, 
are placed one between the os magnum and the unciform, a second between the os 
magnum and the trapezoid, and a third between the trapezium and trapezoid. The 
first of these is much the strongest, and the third is sometimes wanting. 
Three Interosseous. 
3. Articulations of the Two Rows of Carpal Bones with each other. 
The articulations between the two rows of the carpus consist of a kind of enar- 
throdial joint in the middle, formed by the reception of the head of the os magnum 
into a cavity formed by the scaphoid and semilunar bones, and of an arthrodial 
joint on each side, the outer one formed by the articulation of the scaphoid with 
the trapezium and trapezoid, the internal one by the articulation of the cuneiform 
and unciform. The articular surfaces are covered by a thin layer of cartilage, and 
connected by the following ligaments: 
Anterior or Palmar. 
Posterior or Dorsal. 
External Lateral. 
Internal Lateral. 
The Anterior or Palmar Ligaments consist of short fibres which pass, for the 
most part, from the palmar surface of the bones of the first row to the front of the 
os magnum. 
The Posterior or Dorsal Ligaments consist of short, irregular bundles of fibres 
passing between the bones of the first and second row on the dorsal surface of the 
carpus. 
The Lateral Ligaments are very short; they are placed, one on the radial, the 
other on the ulnar, side of the carpus; the former, the stronger and more distinct, 
connecting the scaphoid and trapezium bones; the latter, the cuneiform and unci- 
form ; they are continuous with the lateral ligaments of the wrist-joint. 
The Common Synovial Membrane of the Carpus is very extensive; it 
passes from the under surface of the' scaphoid, semilunar, and cuneiform bones to 
the upper surface of the bones of the second row, sending upward two prolongations 
between the scaphoid and semilunar and the semilunar and cuneiform, sending down- 
ward three prolongations between the four bones of the second row, which are 338 
ARTICULA TIONS. 
further continued downward into the carpo-metacarpal j oints of the four inner 
carpal bones, and also for a short distance between the metacarpal bones. There is 
a separate synovial membrane between the pisiform and cuneiform bones. 
Actions.-The articulation of the hand and wrist, considered as a whole, is 
divided by Meyer1 into three parts: 1. The radius and the triangular cartilage; 2, 
the hand proper-viz. the metacarpal bones with the four carpal bones on which 
they are supported, the trapezium, trapezoid, os magnum, and unciform; and 3, 
the meniscus, formed by the scaphoid, semilunar, and cuneiform, the pisiform bone 
having no essential part in the movements of the hand. 
These three elements form two joints: 1, The anterior, between the hand and 
meniscus (transverse or mid-carpal joint, as it may be called), mainly ginglymoid 
in character; 2, the posterior (wrist-joint proper), between the meniscus and bones 
of the forearm, chiefly arthrodial. 
1. The joint between the scaphoid, semilunar, and cuneiform and the second 
row of the carpus or mid-carpal joint is made up of three distinct portions: in the 
centre the head of the os magnum and the superior surface of the unciform articu- 
late with the deep, cup-shaped cavity formed by the scaphoid and semilunar bones, 
and constitute a sort of ball-and-socket joint. On the outer side the trapezium 
and trapezoid articulate with the scaphoid, and on the inner side the unciform artic- 
ulates with the cuneiform, forming gliding joints. In flexion and extension at the 
mid-carpal joint, which is the movement most freely enjoyed, the trapezium and 
trapezoid on the radial side and the unciform on the ulnar side glide forward and 
backward on the scaphoid and cuneiform respectively, while the head of the os 
magnum and the superior surface of the unciform rotate in the cup-shaped cavity 
of the scaphoid and semilunar. Flexion at this joint would appear to be more free 
than extension. A very trifling amount of rotation is also permitted, the head of 
the os magnum rotating round a vertical axis drawn through its own centre, while 
at the same time a slight gliding movement takes place in the lateral joints. 
2. The articulation between the forearm and carpus is a true condyloid articula- 
tion, and therefore all movements but rotation are permitted. Flexion and exten- 
sion are the most free, and of these a greater amount of extension than flexion is 
permitted on account of the articulating surfaces extending farther on the dorsal 
than on the palmar aspect of the carpal bones. In this movement the carpal bones 
rotate on a transverse axis drawn between the tips of the styloid processes of the 
radius and ulna. A certain amount of adduction (or ulnar flexion) and abduction 
(or radial flexion) is also permitted. Of these, the former is considerably greater 
in extent than the latter. In this movement the carpus revolves upon an antero- 
posterior axis drawn through the centre of the wrist. Finally, circumduction is 
permitted by the consecutive movements of adduction, extension, abduction, and 
flexion, with intermediate movements between them. There is no rotation, but this 
is provided for by the supination and pronation of the radius on the ulna. 
IX. Carpo-metacarpal Articulations. 
1. Articulation of the Metacarpal Bone of the Thumb with the Tra- 
pezium. 
This is a joint of reciprocal reception, and enjoys great freedom of movement, on 
account of the configuration of its articular surfaces, which are saddle-shaped [the 
saddle-shaped surfaces of the two bones being at right angles to each other], so that 
on section each bone appears to be received into a cavity in the other, according to 
the direction in which they are cut. It has a capsular ligament and a synovial 
membrane. 
The Capsular Ligament is a thick but loose capsule which passes from the 
circumference of the upper extremity of the metacarpal bone to the rough edge 
bounding the articular surface of the trapezium; it is thickest externally and 
behind, and lined by a separate synovial membrane. 
1 Reichert u. Du Bois Reymond, Archiv, 1866. CARPO-METACARPAL ARTICULA TIONS. 
339 
2. Articulations of the Metacarpal Bones of the Fingers with the 
Carpus. 
The joints formed between the carpus and four inner metacarpal bones are con- 
nected together by dorsal, palmar, and interosseous ligaments. 
The Dorsal Ligaments, the strongest and most distinct, connect the carpal and 
metacarpal bones on their dorsal surface. The second metacarpal bone receives two 
fasciculi-one from the trapezium, the other from the trapezoid; the third meta- 
carpal receives two-one from the trapezoid, and one from the os magnum; the 
fourth, two-one from the os magnum, and one from the unciform; the fifth receives 
a single fasciculus from the unciform bone. 
The Palmar Ligaments have a somewhat similar arrangement on the palmar 
surface, with the exception of the third metacarpal, which has three ligaments-an 
external one from the trapezium, situated above the sheath of the tendon of the 
Flexor carpi radialis; a middle one, from the os magnum ; and an internal one, 
from the unciform. 
The Interosseous Ligaments consist of short, thick fibres which are limited to 
one part of the carpo-metacarpal articulation; they connect the contiguous inferior 
angles of the os magnum and unciform with the adjacent surfaces of the third and 
fourth metacarpal bones. 
The synovial membrane is a continuation of that between the two rows of 
carpal bones. Occasionally the articulation of the unciform with the fourth and 
fifth metacarpal bones has a separate synovial membrane. 
The synovial membranes of the wrist (Fig. 260) are thus seen to be five in 
number. The first, the membrana sacciformis, passes from the low'er end of the 
ulna to the sigmoid cavity of the 
radius, and lines the upper surface 
of the triangular fibro-cartilage. 
The second passes from the lower 
end of the radius and interarticular 
fibro-cartilage above to the bones of 
the first row below. The third, the 
most extensive, passes between the 
contiguous margins of the two rows 
of carpal bones-between the bones 
of the second row to the carpal ex- 
tremities of the four inner metacar- 
pal bones. The fourth is between 
the trapezium and the metacarpal 
bone of the thumb. The fifth is 
between the cuneiform and pisiform 
bones. 
Actions.-The movement per- 
mitted in the carpo-metacarpal ar- 
ticulations is limited to a slight 
gliding of the articular surfaces 
upon each other, the extent of 
which varies in the different joints. 
Thus the articulation of the meta- 
carpal bone of the thumb with the 
trapezium is the most movable, then 
the fifth metacarpal, and then the 
fourth. The second and third are almost immovable. In the articulation of the 
metacarpal bone of the thumb with the trapezium the movements permitted are 
flexion, extension, adduction, abduction, and circumduction. 
[The movements of the metacarpus, are thus seen to be widest at the margins 
and least in the centre. This, together with the varied lengths and movements of 
Fig. 260. 
Vertical Section through the Articulations at the Wrist, 
showing the five synovial membranes. 340 
ARTICULATIONS. 
the fingers, is very important in adapting the han ' to grasp the many different- 
shaped bodies we have to seize. We can thus fit the hand to the surface of a ball, 
a cylinder, etc., and even, to some extent, to any irregular body. 
Three very marked lines in the palm are produced by these movements: (1) 
that encircling the ball of the thumb; (2) that running from between the 
thumb and forefinger toward the ulnar border of the hand; and (3) me running 
from between the fore and middle fingers to the ulnar border of the hand. These 
[Fig. 261. 
kKHUCkLE WEB 
Palm of Hand, showing the relations of the knuckles and the web of the fingers. The dots show the points cor- 
responding to the knuckle-joints. The interval between the transverse fibres of the palmar fascia and the 
fibres of Gerdy (Fig. 321, p. 451) extends from the level of the knuckles nearly to the web.-W. W. K.] 
last two correspond to the knuckle-joints, and are produced by their constant 
flexion. It is very important to note that the web of the fingers runs far beyond 
the knuckles (Fig. 261).] 
3. Articulations of the Metacarpal Bones with each other. 
The carpal extremities of the four inner metacarpal bones articulate with one 
another at each side by small surfaces covered with cartilage and connected together 
by dorsal, palmar, and interosseous ligaments. 
The Dorsal and Palmar Ligaments pass transversely from one bone to another 
on the dorsal and palmar surfaces. The Interosseous Ligaments pass between their 
contiguous surfaces, just beneath their lateral articular facets. 
The synovial membrane between the lateral facets is a reflection from that 
between the two rows of carpal bones. 
The digital extremities of the metacarpal bones are connected together by a 
narrow fibrous band, the transverse ligament (Fig. 262), which passes transversely 
across their anterior surfaces, and is blended with the ligaments of the metacarpo- 
phalangeal articulations. Its anterior surface presents four grooves for the passage 
of the flexor tendons. Its posterior surface blends with the ligaments of the meta- 
carpo-phalangeal articulations. 
These articulations are of the condyloid kind, formed by the reception of the 
rounded head of the metacarpal bone into a superficial cavity in the extremity of 
the first phalanx. They are connected by the following ligaments: 
X. Metacarpophalangeal Articulations (Fig. 262). 
Anterior. 
Two Lateral. ARTICULATIONS OF THE LOWER EXTREMITY. 
341 
The Anterior Ligaments (Grlenoid Ligaments of Cruveilhier) are thick, dense, 
fibrous structures placed on the 
palmar surface of the joints in 
the intervals between the lat- 
eral ligaments, to which they 
are connected ; they are loosely 
united to the metacarpal bone, 
but very firmly to the base 
of the first phalanges. Their 
palmar surface is intimately 
blended with the transverse 
ligament, forming a groove 
for the passage of the flexor 
tendons, the sheath surround- 
ing which is connected to 
each side of the groove. By 
their deep surface they form 
part of the articular surface 
for the head of the metacar- 
pal bone, and are lined by a 
synovial membrane. 
The Lateral Ligaments are 
strong rounded cords placed one 
on each side of the joint, each 
being attached by one extrem- 
ity to the posterior tubercle on 
the side of the head of the met- 
acarpal bone, and by the other 
to the contiguous extremity of 
the phalanx. 
The Posterior Ligament 
is supplied by the extensor 
tendon placed over the back 
of each joint. 
Actions.-The movements 
which occur in these joints are 
flexion, extension, adduction, 
abduction, and circumduction; 
the lateral movements are very limited. 
Fig. 262. 
Metacarpo - pJtala ngeal 
Artic1! 
LATERAL LICAMENT- 
Grooves for Flexor tendons 
LATERAL LIC.- 
Phalangeal 
Artic ™ 
LATERAL LIC- 
Articulations of the Phalanges. 
XI. Articulations of the Phalanges. 
These are ginglymus joints, connected by the following ligaments: 
The arrangement of these ligaments is similar to that of those in the metacarpo- 
phalangeal articulations; the extensor tendon supplies the place of a posterior lig- 
ament. 
Actions.-The only movements permitted in the phalangeal joints are flexion 
and extension; these movements are more extensive between the first and second 
phalanges than between the second and third. The movement of flexion is very 
considerable, but the extension is limited by the anterior and lateral ligaments. 
Anterior. 
Two Lateral. 
ARTICULATIONS OF THE LOWER EXTREMITY. 
The Articulations of the Lower Extremity comprise the following groups : I. The 
hip-joint. II. The knee-joint. III. The articulations between the tibia and fibula. 342 
ARTICULA TIONS. 
IV. The ankle-joint. V. The articulations of the tarsus. VI. The tarso-metatar- 
sal articulations. VII. The metatarso-phalangeal articulations. VIII. The artic- 
ulations of the phalanges. 
I. Hip-joint (Fig. 263). 
This articulation is an enarthrodial or ball-and-socket joint, formed by the recep- 
tion of the head of the femur into the cup-shaped cavity of the acetabulum. The 
articulating surfaces are covered with cartilage, that on the head of the femur being 
Fig. 263. 
Left Hip-joint laid open. 
thicker at the centre than at the circumference, and covering the entire surface, with 
the exception of a depression just below its centre for the ligamentum teres; that 
covering the acetabulum is much thinner at the centre than at the circumference. 
It forms an incomplete cartilaginous ring of a horseshoe shape, deficient below and 
in front, and having in its centre a circular depression, which is occupied in the 
recent state by a mass of fat surrounded by synovial membrane. The ligaments 
of the joint are the 
Capsular. 
Ilio-femoral. 
Teres. 
Cotyloid. 
Transverse. 
The Capsular Ligament is a strong, dense, ligamentous capsule embracing the 
margin of the acetabulum above and surrounding the neck of the femur below. 
Its upper circumference is attached to the acetabulum two or three lines external 
to the cotyloid ligament; but opposite to the notch where the margin of this cavity 
is deficient it is connected with the transverse ligament, and by a few fibres to the 
edge of the obturator foramen. Its lower circumference surrounds the neck of the 
femur, being attached in front to the spiral or anterior intertrochanteric line; above, HIP-JOINT. 
343 
to the base of the neck ; behind, to the middle of the neck of the bone about half 
an inch above the posterior intertrochanteric line. From this insertion the fibres 
are reflected upward over the neck of the 
femur, forming a sort of tubular sheath which 
blends with the periosteum and can be traced 
as far as the articular cartilage. It is much 
thicker at the upper and fore part of the joint, 
where the greatest amount of resistance is re- 
quired, than below and internally, where it is 
thin, loose, and longer than in any other part. 
It consists of two sets of fibres, circular and 
longitudinal. The circular fibres are most 
abundant at the lower and back part of the 
capsule, while the longitudinal fibres are great- 
est in amount at the front and upper part of 
the joint, where they form distinct bands or 
accessory ligaments, of which the most import- 
ant is the ilio-femoral. The other accessory 
bands are known as the pubo-femoral, passing 
from the ilio-pectineal eminence to the front 
of the capsule; the ilio-trochanteric, from the 
anterior inferior spine of the ilium to the front 
of the great trochanter; and the ischio-cap- 
sular, passing from the ischium, just below 
the acetabulum, to blend with the circular 
fibres at the lower part of the joint. Its 
external surface (Fig. 247, p. 318) is rough, 
covered by numerous muscles, and separated 
in front from the Psoas and Iliacus by a syno- 
vial bursa, which not unfrequently communi- 
cates by a circular aperture with the cavity of 
the joint. It differs from the capsular ligament of the shoulder in being much less 
loose and lax, and in not being perforated for the passage of a tendon. 
The Ilio-femoral Ligament (Fig. 247, p. 318, and Fig. 264) is an accessory band 
[Fig. 264. 
Hip-joint, showinginvertedY-iigament(Bigeiow).] 
Fig. 265. 
The Hip-joint laid open from the Pelvis, to show the Ligamentum Teres put on the stretch by rotation of the 
Femur outward. 
of fibres extending obliquely across the front of the joint; it is intimately connect- 
ed with the capsular ligament, and serves to strengthen it in this situation. It is 
attached above to the lower part of the anterior inferior spine of the ilium, and, 344 
ARTIC UL ATI 0 NS. 
spreading out into a flat triangular band, it is attached below into the whole length 
of the anterior intertrochanteric line. Its lower part, instead of forming a flat band, 
is sometimes bifurcated, and forms two bands, the one of which passes almost verti- 
cally to the lower part of the intertrochanteric line, the other obliquely to the upper 
part of the line. This arrangement Bigelow seems to regard as the usual one, so 
that he describes it under the name of the "inverted Y-ligament."1 [)This 
Fig. 266. 
The Same View of the Hip as in the former figure, to show the Ligamentum Teres put on the stretch by adduc- 
tion in the flexed position. 
"inverted Y-ligament " is of such importance, particularly in relation to disloca- 
tions and their reduction by manipulation, that its careful examination and dis- 
section are' especially recommended to the student. It is well shown in Fig. 
264.] 
The Ligamentum Teres is a triangular band of fibres implanted, by its apex, 
into the depression a little behind and below the centre of the head of the femur, 
and by its broad base, which consists of two bundles of fibres, into the margins of 
the notch at the bottom of the acetabulum, becoming blended with the transverse 
ligament. It is formed of a bundle of fibres, the thickness and strength of which 
are very variable, surrounded by a tubular sheath of synovial membrane. Some- 
times only the synovial fold exists, or the ligament may be altogether absent. The 
use of the round ligament is to check rotation outward, as well as adduction in the 
flexed position (Figs. 265, 266): it thus assists in preventing dislocation of the head 
of the femur forward and outward-an accident likely to occur from the necessary 
mechanism of the joint if not provided against by this ligament and the thick ante- 
rior part of the capsule.2 
The Cotyloid Ligament is a fibro-cartilaginous rim attached to the margin of 
the acetabulum, the cavity of which it deepens; at the same time it protects the 
edges of the bone and fills up the inequalities on its surface. It bridges over the 
notch as the transverse ligament, and thus forms a complete circle which closely 
surrounds the head of the femur and assists in holding it in its place, acting as a 
sort of valve and preventing the admission of air into the joint. It is prismoid in 
form, its base being attached to the margin of the acetabulum and its opposite edge 
being free and sharp, whilst its two surfaces are invested by synovial membrane, the 
external one being in contact with the capsular ligament, the internal one being 
inclined inward, so as to narrow the acetabulum and embrace the cartilaginous sur- 
face of the head of the femur. It is much thicker above and behind than below 
1 Bigelow, On the Hip-joint. 
2 See an interesting paper, "On the Use of the Round Ligament of the Hip-joint," by Dr. J. 
Struthers, Edinburgh Medical Journal, 1858. This ligament is best studied with the assistance of a 
preparation in which the floor of the acetabulum has been removed with a trephine, and the liga- 
ment exposed by cleaning away the fat. Mr. Savory, without denying the other uses attributed to 
this ligament, says that it is always made tense in the upright position, and is still further tightened 
in standing on one leg; and therefore he maintains that its main function is to support the weight 
of the body and distribute its pressure equally over the whole surface of the acetabulum and head 
of the femur (Lancet, May 23, 1874). [The ligamentum teres is sometimes absent.] HIP-JOINT. 
345 
and in front, and consists of close compact fibres which arise from different points 
of the circumference of the acetabulum and interlace with one another at very acute 
angles. 
The Transverse Ligament is in reality a portion of the cotyloid ligament, 
strengthened in this situation by some deep fibres. It consists of strong flattened 
fibres which cross the notch at the lower part of the acetabulum and convert it into 
a foramen. An interval is left beneath the ligament for the passage of nutrient 
vessels to the joint. 
The synovial membrane is very extensive. Commencing at the margin of the 
cartilaginous surface of the head of the femur, it covers all that portion of the neck 
which is contained within the joint; from the neck it is reflected on the internal 
surface of the capsular ligament, covers both surfaces of the cotyloid ligament and 
the mass of fat contained in the fossa at the bottom of the acetabulum, and is pro- 
longed in the form of a tubular sheath around the ligamentum teres as far as the 
head of the femur. 
The muscles in relation with the joint are, in front, the Psoas and Iliacus, sep- 
arated from the capsulai' ligament by a synovial bursa,; above, the straight head of 
the Rectus and Gluteus minimus, the latter being closely adherent to the capsule; 
Fig. 267. 
Relation of Muscles to the Capsule of the Hip-joint (from a drawing by Mr. F. A. Barton). 
internally, the Obturator externus and Pectineus; behind, the Pyriformis, Gemellus 
superior, Obturator internus, Gemellus inferior, Obturator externus, and Quadratus 
femoris (Fig. 267). 
The Arteries supplying the joint are derived from the obturator, sciatic, internal 
circumflex, and gluteal. 
The Nerves are articular branches from the sacral plexus, great sciatic, obturator, 
and accessory obturator nerves. 
Actions.-The movements of the hip, like [those of] all enarthrodial joints, 
are very extensive; they are flexion, extension, adduction, abduction, circumduc- 
tion, and rotation. 
The hip-joint presents a very striking contrast to the other great enarthrodial 346 
ARTICULATIONS. 
joint-the shoulder-in the much more complete mechanical arrangements for its 
security and for the limitation of its motions. In the shoulder, as we have seen, the 
head of the humerus is not adapted at 
all in shape to the glenoid cavity, and is 
hardly restrained in any of its ordinary 
movements by the capsular ligament. In 
the hip-joint, on the contrary, the head 
of the femur is closely fitted to the ace- 
tabulum for a distance extending over, 
nearly half a sphere, and at the margin 
of the bony cup it is still more closely 
embraced by the ligamentous ring of the 
cotyloid ligament, so that the head of the 
femur is held in its place by that liga- 
ment even when the fibres of the capsule 
have been quite divided (Humphry). The 
anterior portion of the capsule, described 
as the ilio-femoral or accessory ligament, 
is the strongest of all the ligaments in 
the body, and is put on the stretch by 
any attempt to extend the femur beyond 
a straight line with the trunk. That is to 
say, this ligament is the chief agent in 
maintaining the erect position without 
muscular fatigue, the action of the extensor muscles of the buttock being bal- 
anced by the tension of the ilio-femoral and capsular ligaments. The security of 
the joint is also provided for by the two bones being directly united through the 
ligamentum teres. Flexion of the hip-joint is arrested by the soft parts of the 
thigh and abdomen being brought into contact;1 extension, by the tension of the 
ilio-femoral ligament and front of the capsule; adduction, by the outer band of the 
ilio-femoral ligament and the ilio-trochanteric ligament, and in the flexed position 
of the limb by the ligamentum teres; abduction, by the lower portion of the ilio- 
femoral ligament and the pubo-femoral band; rotation outward, by the outer part 
of the ilio-femoral ligament and the ligamentum teres; and rotation inward, by the 
ischio-capsular ligament and the hinder part of the capsule. The muscles which 
flex the femur on the pelvis are the Psoas, Iliacus, Rectus, Sartorius, Pectineus, 
and Adductor brevis. Extension is mainly performed by the Gluteus maximus, 
assisted by the hamstring muscles. The thigh is adducted by the Adductores mag- 
nus, longus and brevis, the Pectineus, Sartorius, and Gracilis, and abducted by the 
Gluteus maximus, medius, and minimus. The muscles which rotate the thigh intvard 
are the anterior fibres of the Gluteus medius, the Gluteus minimus, and the Tensor 
vaginae feraoris; while those which rotate it outward are the posterior fibres of the 
Gluteus medius, the Pyriformis, Obturator externus and internus, Gemellus superior 
and inferior, Quadratus femoris, Psoas, Iliacus, Gluteus maximus, the three Adduc- 
tors, and the Pectineus. 
[Fig. 268. 
._LIG. 
TERES 
OBTUR. 
" MEMB. 
Vertical Section through Hip-joint (Henle).] 
II. Knee-joint. 
The knee-joint was formerly described as a ginglymus or hinge-joint, but is really 
of a much more complicated character. It must be regarded as consisting of three 
articulations together: one between each condyle of the femur and the corresponding 
tuberosity of the tibia, which are condyloid joints ; and one between the patella and 
the femur, which is partly arthrodial, but not completely so, since the articular sur- 
faces are mutually adapted to each other, so that the movement is not a simply glid- 
ing one. This view of the construction of the knee-joint receives confirmation from 
1 The hip-joint cannot be completely flexed, in most persons, without at the same time flexing the 
knee, on account of the shortness of the hamstring muscles (Cleland, Journ. of Anat. and Phys., No. 1, 
Old Series, p. 87). [See ligamentous action of muscles, p. 301]. KNEE-JOINT. 
347 
the study of the articulations in some of the lower mammals, where three synovial 
membranes are sometimes found, corresponding to these three subdivisions, either 
entirely distinct or only connected together by small communications. This view 
is further rendered probable by the existence of the two crucial ligaments within 
the joint, which must be regarded as the external and internal lateral ligaments of the 
inner and outer joints respectively. The existence of the ligamentum mucosum would 
further indicate a tendency to separation of the synovial cavity into two minor sacs, 
one corresponding to each joint. [For a comparison of the angle formed between the 
thigh and leg at the knee with the similar angle at the elbow, see p. 242.] 
The bones entering into the formation of the knee-joint are the condyles of the 
femur above; the head of the tibia below, and the patella in front. The articular 
surfaces are covered with cartilage and connected together by ligaments, some of 
which are placed on the exterior of the joint, whilst others occupy its interior. 
External Ligaments. 
Anterior, or Ligamentum patellae. 
Posterior, or Ligamentum posticum 
Winslowii. 
Internal Lateral. 
Two External Lateral. 
Capsular. 
Interior Ligaments. 
Anterior, or External Crucial. 
Posterior, or Internal Crucial. 
Two Semilunar Fibro-cartilages. 
Transverse. 
Coronary. 
Ligamentum mucosum. 
Ligamenta alaria. 
The Anterior Ligament, or Ligamentum patellae (Fig. 269), is that portion 
of the common tendon of the extensor muscles of the thigh which is continued from 
the patella to the tubercle of the tibia, supplying the place of an anterior ligament. 
It is a strong, flat, ligamentous band about three inches in length, attached above 
to the apex of the patella and the rough depression on its posterior surface; below, 
to the lower part of the tuberosity of the tibia, its superficial fibres being continuous 
across the front of the patella with those of the tendon of the Quadriceps extensor. 
[The ligamentum patellae is best shown by trying to lift a heavy bureau or other 
weight by one foot, the leg being in semi-extension.] Two synovial bursae are con- 
nected with this ligament and the patella: one is interposed between the patella and 
the skin covering its anterior surface [see p. 348] ; the other of small size, between 
the ligamentum patellae and the upper part of the tuberosity of the tibia. The pos- 
terior surface of the ligament is separated above from the knee-joint by a large mass 
of adipose tissue [this fatty tissue recedes into the space between the bones when 
the leg is flexed, but is forced out on each side of the ligament when the leg is 
extended, and is not to be mistaken for fluid inside the joint] : its lateral margins 
are continuous with the aponeurosis derived from the Vasti muscles. 
The Posterior Ligament, Ligamentum posticum Winslowii1 (Fig. 270), is 
a broad, flat, fibrous band which covers over the whole of the back part of the joint. 
It consists of a central and two lateral portions, the latter formed chiefly of vertical 
fibres, which arise above from the condyles of the femur and are connected below 
with the back part of the head of the tibia, being closely united with the tendons 
of the Gastrocnemius, Plantaris, and Popliteus muscles ; the central portion is formed 
of fasciculi obliquely directed and separated from one another by apertures for the 
passage of vessels and nerves. The strongest of these fasciculi is derived from the 
tendon of the Semimembranosus, and passes from the back part of the inner tube- 
rosity of the tibia obliquely upward and outward to the back part of the outer con- 
dyle of the femur. The posterior ligament forms part of the floor of the popliteal 
space, and the popliteal artery rests upon it. 
The Internal Lateral Ligament is a broad, flat, membranous band, thicker 
behind than in front, and situated nearer to the back than the front of the joint. 
It is attached above to the inner tuberosity of the femur, below to the inner tube- 
rosity and inner surface of the shaft of the tibia to the extent of about two inches. 
It is crossed at its lower part by the aponeurosis of the Sartorius and the tendons 
PThe "oblique fasciculus" is the only part described by Winslow as the "posterior ligament." 
The rest of it is described with the " capsular ligament." ] 348 
ARTICULATIONS. 
of the Gracilis and Semitendinosus muscles, a synovial bursa being interposed. Its 
deep surface covers the anterior portion of the tendon of the Semimembranosus, the 
Fig. 269. 
Fig. 270. 
synovial membrane of the joint, and the inferior internal articular artery and nerve; 
it is intimately adherent to the internal semilunar fibro-cartilage. 
The Long- External Lateral Ligament is a strong, rounded, fibrous cord 
situated nearer to the back than the front of the joint. It is attached above to 
the back part of the outer tuberosity of the femur, below to the outer part of 
the head of the fibula. Its outer surface is covered by the tendon of the Biceps, 
which divides at its insertion into two parts, separated by the ligament. The liga- 
ment has passing beneath it the tendon of the Popliteus muscle and the inferior 
external articular vessels and nerve. 
The Short External Lateral Ligament is an accessory bundle of fibres placed 
behind and parallel with the preceding, attached above to the lower part of the 
outer tuberosity of the femur, below to the summit of the styloid process of the 
fibula. This ligament is intimately connected with the capsular ligament, and has 
passing beneath it the tendon of the Popliteus muscle. 
The Capsular Ligament consists of an exceedingly thin but strong fibrous 
membrane which fills in the intervals left by the preceding ligaments. It is attached 
to the femur immediately above its articular surface, but is incomplete in front, not 
extending beneath the extensor tendons; below, to the upper border and sides of 
the patella and the margins of the head of the tibia and interarticular cartilages, and 
is continuous behind with the posterior ligament. This membrane is strengthened 
by fibrous expansions derived from the fascia lata, from the Vasti and Crureus mus- 
cles, and from the Biceps, Sartorius, and tendon of the Semimembranosus. The 
expansions from the fascia lata and Vasti muscles form strong fibrous bands on either 
Right Knee-joint, anterior view. 
Right Knee-joint, posterior view. KNEE-JOINT. 
349 
side of the patella, which are sometimes called the lateral patellar ligaments. [The 
tendon of the Quadriceps extensor (the so-called ligamentum patellae) is so strong 
and tense that any liquid accumulating inside the knee-joint distends only the rela- 
tively weaker capsular ligament, and forms 
a marked swelling on each side of the ten- 
don and below the patella. The contrast 
between this and the median swelling in 
front of the patella in "housemaid's knee" 
is to be borne in mind.] 
The Crucial are two interosseous liga- 
ments of considerable strength situated in 
the interior of the joint, nearer its poste- 
rior than its anterior part. They are called 
crucial because they cross each other, some- 
what like the lines of the letter X, and have 
received the names anterior and posterior 
from the position of their attachment to the 
tibia. 
The Anterior or External Crucial Lig- 
ament (Fig. 271), smaller than the posterior, 
is attached to the inner side of the depression 
in front of the spine of the tibia, being blend- 
ed with the anterior extremity of the exter- 
nal semilunar fibro-cartilage, and, passing ob- 
liquely upward, backward, and outward, is 
inserted into the inner and back part of the 
outer condyle of the femur. 
The Posterior or Internal Crucial Lig- 
ament is larger in size, but less oblique in 
its direction than the anterior. It is at- 
tached to the back part of the depression 
behind the spine of the tibia, to the pop- 
liteal notch, and to the posterior extremity 
of the external semilunar fibro-cartilage, 
and passes upward, forward, and inward to be inserted into the outer and fore part 
of the inner condyle of the femur. As it crosses the anterior crucial ligament a 
fasciculus is given off from it 
which blends with the posterior 
part of that ligament. It is in 
relation in front with the ante- 
rior crucial ligament, behind 
with the ligamentum posticum 
Winslowii. 
The Semilunar Fibro-car- 
tilages (Fig. 272) are two cres- 
centic lamellae which are at- 
tached to the margins of the 
head of the tibia, and serve to 
deepen its surface for articula- 
tion with the condyles of the 
femur. The circumference of 
each cartilage is thick and con- 
vex, the inner free border thin 
and concave. Their upper sur- 
faces are concave, and in relation with the condyles of the femur; their lower sur- 
faces are flat, and rest upon the head of the tibia. Each cartilage covers nearly 
the outer two-thirds of the corresponding articular surface of the tibia, leaving the 
Fig. 271. 
Right Knee-joint, showing internal ligaments. 
Fig. 272. 
Head of Tibia, with Semilunar Cartilages, etc., seen from above, 
right side. 350 
ARTICULATIONS. 
inner third uncovered; both surfaces are smooth and invested by synovial mem- 
brane. 
The Internal Semilunar Fibro-cartilage is nearly semicircular in form, a 
little elongated from before backward, and broader behind than in front; its 
convex border is united to the internal lateral ligament and to the head of the 
tibia by means of the coronary ligaments; its anterior extremity, thin and pointed, 
is firmly implanted into a depression on the anterior margin of the head of the 
tibia in front of the anterior crucial ligament; its posterior extremity into the 
depression behind the spine, between the attachment of the external cartilage and 
posterior crucial ligament. 
The External Semilunar Fibro-cartilage forms nearly an entire circle, cover- 
ing a larger portion of the articular surface than the internal one. It is grooved 
on its outer side for the tendon of the Popliteus muscle. Its circumference is held 
in connection with the head of the tibia by means of the coronary ligaments, and 
its two extremities are firmly implanted in the depressions in front of and behind 
the spine of the tibia. These extremities at their insertion are interposed between 
the attachments of the internal cartilage, the anterior extremity being attached, in 
front of the spine of the tibia, to the outer side of the anterior crucial ligament. The 
posterior is attached behind the spine, but in front of the posterior extremity of 
the internal cartilage. Just before its insertion it gives off a strong fasciculus 
which passes obliquely upward and outward, to be inserted into the inner condyle 
of the femur close to the attachment of the posterior crucial ligament. Occasion- 
ally a small fasciculus is given off which passes forward to be inserted into the 
back part of the anterior crucial ligament. The external semilunar fibro-carti- 
lage gives off from its anterior border a fasciculus which forms the transverse 
ligament. 
The Transverse Ligament is a band of fibres which passes transversely from 
the anterior convex margin of the external semilunar cartilage to the anterior 
extremity, of the internal cartilage ; its 
thickness varies considerably in differ- 
ent subjects, and it is sometimes absent 
altogether. 
The Coronary Ligaments consist of 
numerous short fibrous bands which con- 
nect the convex border of the semilunar 
cartilages with the circumference of the 
head of the tibia and with the other liga- 
ments surrounding the joint. 
The synovial membrane of the 
knee-joint is the largest and most ex- 
tensive in the body. Commencing at 
the upper border of the patella, it forms 
a short cul-de-sac beneath the Quadriceps 
extensor tendon on the thigh ; this com- 
municates with a synovial bursa inter- 
posed between the tendon and the front 
of the femur, by an orifice of variable 
size. [These two cavities are practically 
one. If a blowpipe be inserted through 
a hole drilled in the patella or secured 
in a small opening in the capsular liga- 
ment, and the cavity of the joint be dis- 
tended by air, the synovial sac will be found to extend usually two inches above the 
upper margin of the patella-an important fact to be remembered in operations in 
this region. In synovitis of this joint the.distension thus extends above the patella, 
and if marked it will float the patella away from the femur.] On each side of the 
patella the synovial membrane extends beneath the aponeurosis of the Vasti muscles, 
[Fig. 273. 
SYNOV. MEMB. KNEE.JOINT 
PRE- 
f PATELLAR 
BURSA. 
SUB - 
' PATELLAR 
BURSA 
Sagittal Section through Knee-joint (Volz).] KNEE-JOINT. 
351 
and more especially beneath that of the Vastus internus; and below the patella it is 
separated from the anterior ligament by a considerable quantity of adipose tissue. 
In this situation it sends off a triangular prolongation, containing a few ligament- 
ous fibres, which extends from the anterior part of the joint below the patella to 
the front of the intercondyloid notch. This fold has been termed the ligamentum 
muco-sum. The ligamenta alaria consist of two fringe-like folds which extend from 
the sides of the ligamentum mucosum upward and laterally between the patella and 
femur. The synovial membrane invests the semilunar fibro-cartilages, and on the 
back part of the external one forms a cul-de-sac between the groove on its surface 
and the tendon of the Popliteus; it is continued to the articular surface of the tibia, 
surrounds the crucial ligaments and the inner surface of the ligaments which enclose 
the j oint; lastly, it approaches the condyles of the femur, and from them is con- 
tinued on to the lower part of the front of the shaft. The pouch of synovial 
membrane between the extensor tendon and front of the femur is supported during 
the movements of the knee by a small muscle, the Subcrureus, which is inserted 
into it. 
The folds of synovial membrane and the fatty processes contained in them act, as 
it seems, mainly as padding to fill up interspaces and obviate concussions. 
The Bursce in connection with the synovial membrane will be found described 
with the regional anatomy of the popliteal space. 
The Arteries supplying the joint are derived from the anastomotic branch of the 
femoral articular branches of the popliteal, recurrent branch of the anterior tibial, 
and descending branch from the external circumflex of the profunda. 
The Nerves are derived from the obturator, anterior crural, and external and 
internal popliteal. 
Actions.-The knee-joint permits of movements of flexion and extension, and 
in certain positions of slight rotation inward and outward. The movement of flex- 
ion and extension does not, however, take place in a simple, hinge-like manner, as 
in other joints, but is a complicated movement consisting of an irregular motion 
combining a certain amount of gliding and rotation, so that the same part of one 
articular surface is not always applied to the same part of the other articular surface, 
and the axis of motion is not a fixed one. If the recently-dissected knee-joint is 
examined while in a condition of extreme flexion, the posterior rounded extremities 
of the condyles of the femur will be found to be resting against the posterior part 
of the articular facets on the tibia, and if a simple hinge-like movement were to 
take place, the axis, round which the revolving movement of the tibia occurs, would 
be in the back part of the condyle. If the leg is now brought forward into a posi- 
tion of semiflexion, the upper surface of the tibia will be seen to glide over the 
condyles of the femur, so that the middle part of the articular facets are in contact, 
and the axis of rotation must therefore be shifted forward to nearer the centre of 
the condyles. If the leg is now brought into the extended position, a still further 
gliding takes place, and a further shifting forward of the axis of rotation. This is 
not, however, a simple movement, but is accompanied by a certain amount of rota- 
tion outward round a vertical axis drawn through the centre of the head of the 
tibia. This rotation is due to the greater length of the internal condyle, and to 
the fact that the anterior portion of its articular surface is inclined obliquely out- 
ward. In consequence of this it will be seen that toward the close of the movement 
of extension-that is to say, just before complete extension is effected-the tibia is 
directed obliquely upward and outward over this oblique surface on the inner con- 
dyle, and the leg is therefore necessarily rotated outward. In flexion of the joint 
the converse of these movements takes place. The tibia glides backward round 
the end of the femur, and at the commencement of the movement the tibia is 
directed downward and inward along the oblique curve of the inner condyle, thus 
causing an inward rotation to the leg. [This "pronation" and "supination" of 
the leg amounts to about 36°. It begins when the leg is flexed at 150° to 155°, 
and becomes more pronounced as the joint is further flexed.] 
During flexion and extension the patella moves on the lower end of the femur, 352 
ARTICULATIONS. 
but this movement is not a simple gliding one; for if the articular surface of this 
bone is examined, it will be found to present on each side of the central vertical 
ridge two less-marked transverse ridges, which divide each half of the bone into' 
three facets, and does not present a uniform curved surface, as would be the case if 
a simple gliding movement took place. These three facets correspond to and denote 
the parts of the bone respectively in contact with the condyles of the femur during 
flexion, semiflexion, and extension. In flexion only the upper facets on the patella 
are in contact with the condyles of the femur; the lower two-thirds of the bone rest 
upon the mass of fat which occupies the space between the femur and tibia. In the 
semiflexed position of the joint the middle facets on the patella rest upon the most 
prominent portion of the condyles, and thus afford increased leverage to the quad- 
riceps by increasing its distance from the centre of motion. In complete extension 
the patella is drawn up, so that only the lower facets are in contact with the artic- 
ular surfaces of the condyles. 
In addition to the slight rotation during flexion and extension the tibia enjoys 
an independent rotation on the condyles of the femur in certain positions of the 
joint. This takes place in the semiflexed position of the limb when all the liga- 
ments are relaxed. 
During flexion the ligamentum patellae is put upon the stretch, as is also the 
posterior crucial ligament in extreme flexion. The other ligaments are all relaxed 
by flexion of the joint, though the relaxation of the anterior crucial ligament is 
very trifling. Flexion is only checked during life by the contact of the leg with 
the thigh. In extension the ligamentum patellae becomes relaxed, and in extreme 
extension completely so, so as to allow free lateral movement to the patella, which 
then rests on the front of the lower end of the femur. The other ligaments, with 
the exception of the posterior crucial, which is partly relaxed, are all on the stretch. 
When the limb has been brought into a straight line extension is checked mainly 
by the tension of all the ligaments except the posterior crucial and ligamentum 
patellae. [In the position at rest, when the weight is thrown on one leg, the knee- 
joint of this leg is slightly over-extended, so as to form an angle the apex of which 
is directed posteriorly, and the posterior ligament is stretched to its utmost in sup- 
porting the leg, and thus resting the muscles. At the same time, the pelvis is tilted 
backward, and supported by the now tense anterior part of the capsular ligament at 
the hip, especially the inverted Y-ligament. The pelvis is still more markedly 
tilted over to the other side, making the other leg relatively the longer, and thus 
necessitating its flexion. It is supported here by the external part of the capsular 
and the A-ligaments. The changes in the level of the pelvis are best seen by com- 
paring the levels of the two anterior superior spines on the living model; or if a 
light rod be fixed by adhesive plaster to these two spines, and the model alternately 
throw his weight on one leg and then on the other, it will show still better. The 
rocking of the pelvis in walking can be excellently shown by this experiment, 
especially in the female model. To make the rod touch the anterior superior spines, 
it should be of this shape, , to fit the projecting abdomen, or a 
straight rod may be fixed to the posterior superior spines, and will show the pelvic 
rocking equally well.] The movements of rotation of which the knee is susceptible 
are permitted in the semiflexed condition by the partial relaxation of both crucial 
ligaments, as well as the lateral ligaments. Rotation inward appears to be limited 
by the tension of the anterior crucial ligament and by the interlocking of the two 
ligaments, but rotation outward does not appear to be cheeked by either ligament, 
since they uncross during the execution of this movement, but by the lateral liga- 
ments, especially the internal. The main function of the crucial ligaments is to act 
as a direct bond of union between the tibia and femur, preventing the former bone 
from being carried too far backward or forward. Thus the anterior crucial ligament 
prevents the tibia being carried too far forward by the extensor tendons, and the 
posterior crucial checks too great movement backward by the flexors. They also 
assist the lateral ligaments in resisting any lateral bending of the joint. The inter- 
articular cartilages are intended, as it seems, to adapt the surface of the tibia to the BETWEEN THE TIBIA AND FIBULA. 
353 
shape of the femur to a certain extent, so as to fill up the intervals which would 
otherwise be left in the varying positions of the joint, and to interrupt the jars 
which would be so frequently transmitted up the limb in jumping or falls on the 
feet.1 The patella is a great defence to the knee-joint from any injury inflicted in 
front, and it distributes upon a large and tolerably even surface during kneeling 
the pressure which would otherwise fall upon the prominent ridges of the condyles: 
it also affords leverage to the Quadriceps extensor muscle to act upon the tibia; and 
Mr. Ward has pointed out2 how this leverage varies in the various positions of the 
joint, so that the action of the muscle produces velocity at the expense of force in 
the commencement of extension, and, on the contrary, at the close of extension 
tends to diminish the velocity, and therefore the shock to the ligaments, whilst in 
the standing position it draws the tibia powerfully forward, and thus maintains it in 
its place. 
Extension of the leg on the thigh is performed by the Quadriceps extensor; 
flexion, by the hamstring muscles, assisted by the Gracilis and Sartorius; rotation 
outward, by the Biceps; and rotation inward, by the Popliteus, Semitendinosus, 
and, to a slight extent, the Semimembranosus. 
m. Articulations between the Tibia and Fibula. 
The articulations between the tibia and fibula are effected by ligaments which 
connect both extremities, as well as the shafts of the bones. They may, conse- 
quently, be subdivided into three sets : 1, The Superior Tibio-fibular articulation ; 
2, the Middle Tibio-fibular articulation; 3, the Inferior Tibio-fibular articulation. 
1. Superior Tibio-fibular Articulation. 
This articulation is an arthrodial joint. The contiguous surfaces of the bones 
present two flat oval facets covered with cartilage and connected together by the 
following ligaments: 
Anterior Superior Tibio-fibular. 
Posterior Superior Tibio-fibular. 
The Anterior Superior Ligament (Fig. 271) consists of two or three broad 
and flat bands which pass obliquely upward and inward from the front of the head 
of the fibula to the front of the outer tuberosity of the tibia. 
The Posterior Superior Ligament is a single thick and broad band which 
passes from the back part of the head of the fibula to the back part of the outer 
tuberosity of the tibia. It is covered by the tendon of the Popliteus muscle. 
A synovial membrane lines this articulation, which at its upper and back part 
is occasionally continuous with that of the knee-joint. 
2. Middle Tibio-fibular Articulation. 
An interosseous membrane extends between the contiguous margins of the tibia 
and fibula, and separates the muscles on the front from those on the back of the 
leg. It consists of a thin aponeurotic lamina composed of oblique fibres, which 
pass downward and outward between the interosseous ridges on the two bones. It 
is broader above than below, and presents at its upper part a large oval aperture 
for the passage of the anterior tibial artery forward to the anterior aspect of the 
leg, and at its lower part an opening for the passage of the anterior peroneal ves- 
sels. It is continuous below with the inferior interosseous ligament, and is perfor- 
1 Prof. Humphry teaches that the interarticular cartilages do not follow the movements of the 
tibia in pronation and supination; so that these movements take place between the tibia and the car- 
tilages, while the chief movements of the joint take place between the cartilages and the femur. If 
this be so, it would establish an interesting analogy with other joints (such as the lower jaw) in which 
interarticular cartilages are present. 
2 Human Osteology, p. 405. 354 
ARTICULATIONS. 
ated in numerous parts for the passage of small vessels. It is in relation in front 
with the Tibialis anticus, Extensor longus digitorum, Extensor proprius pollicis, 
Peroneus tertius, and the anterior tibial vessels and nerve; behind, with the Tib- 
ialis posticus and Flexor longus pollicis. 
3. Inferior Tibio-fibular Articulation. 
This articulation is formed by the rough convex surface of the inner side of the 
lower end of the fibula, connected with a similar rough surface on the outer side of 
the tibia. Below, to the extent of about two lines, these surfaces are smooth and 
covered with cartilage, which is continuous with that of the ankle-joint. The liga- 
ments of this joint are- 
Inferior Interosseous. 
Anterior Inferior Tibio-fibular. 
Posterior Inferior Tibio-fibular. 
Transverse. 
The Inferior Interosseous Ligament consists of numerous short, strong fibrous 
bands which pass between the contiguous rough surfaces of the tibia and fibula, and 
constitute the chief bond of union between the bones. This ligament is continuous 
above with the interosseous membrane. 
The Anterior Inferior Ligament (Fig. 275) is a flat, triangular band of fibres, 
broader below than above, which extends obliquely downward and outward between 
the adjacent margins of the tibia and fibula on the front aspect of the articulation. 
It is in relation in front with the Peroneus tertius, the aponeurosis of the leg, and 
the integument, behind with the inferior interosseous ligament, and lies in contact 
with the cartilage covering the astragalus. 
The Posterior Inferior Ligament, smaller than the preceding, is disposed in a 
similar manner on the posterior surface of the articulation. 
The Transverse Ligament is a long narrow band continuous with the preced- 
ing, passing transversely across the back of the joint from the external malleolus to 
the tibia, a short distance from its malleolar process. This ligament projects below 
the margin of the bones, and forms part of the articulating surface for the astrag- 
alus. 
The synovial membrane lining the articular surface is derived from that of the 
ankle-joint. 
Actions.-The movement permitted in these articulations is limited to a very 
slight gliding of the articular surfaces one upon another. 
IV. Ankle-joint. 
The Ankle is a ginglymus or hinge-joint. The bones entering into its forma- 
tion are the lower extremity of the tibia and its malleolus and the external malle- 
olus of the fibula. These bones are united above, and form an arch to receive the 
upper convex surface of the astragalus and its two lateral facets. The bony sur- 
faces are covered with cartilage and connected together by the following ligaments: 
Anterior. 
Posterior. 
Internal Lateral. 
External Lateral. 
The Anterior Tibio-tarsal Ligament (Fig. 274) is a broad, thin, membranous 
layer attached above to the margin of the articular surface of the tibia, below to 
the margin of the astragalus in front of its articular surface. It is in relation in 
front with the Extensor tendons of the toes, with the tendons of the Tibialis anti- 
cus and Peroneus tertius, and the anterior tibial vessels and nerve; behind, it lies 
in contact with the synovial membrane. 
The Posterior Tibio-tarsal Ligament is very thin, and consists of a few fibres, 
principally transverse, which are attached to the tibia and astragalus close to their 
articular surfaces. Externally it is thicker than internally, where a somewhat ANKLE-JOINT. 
355 
Fig. 274. 
ankle-joint. 
tarsal artic"? 
tarso - metatarsal 
ARTIC 
Ankle-joint: Tarsal and Tarso-metatarsal Articulations, internal view, right side. 
thickened band of transverse fibres are attached to the hollow on the inner surface 
of the external malleolus. 
The Internal Lateral or Deltoid Ligament consists of two layers, superficial 
Fig. 275. 
INFERIOR, TIBIO-FIBULAR 
ARTIC" 
ANKLE-JOINT 
TARSAL ARTIC"? 
TARSO-METATARSAL. ARTICN? 
Ankle-joint: Tarsal and Tarso-metatarsal Articulations, external view, right side. 
and deep. The superficial layer is a strong, flat, triangular band attached above 
to the apex and anterior and posterior borders of the inner malleolus. The most 
anterior fibres pass forward to be inserted into the scaphoid and inferior calcaneo- 356 
ARTICULATIONS. 
scaphoid ligament; the middle descend almost perpendicularly to be inserted into 
the sustentaculum tali of the os calcis; and the posterior fibres pass backward and 
outward to be attached to the inner side of the astragalus. The deeper layer con- 
sists of a short, thick, and strong fasciculus which passes from the apex of the mal- 
leolus to the inner surface of the astragalus, below the articular surface. This liga- 
ment is covered by the tendons of the Tibialis posticus and Flexor longus digitorum 
muscles. 
The External Lateral Ligament (Fig. 275) consists of three fasciculi, tak- 
ing different directions and separated by distinct intervals; for which reason it is 
described by some anatomists as three distinct ligaments.1 This would seem the 
preferable description, were it not that the old nomenclature has passed into 
general use. 
The anterior fasciculus, the shortest of the three, passes from the anterior mar- 
gin of the summit of the external malleolus downward and forward to the astragalus 
in front of its external articular facet. 
The posterior fasciculus, the most deeply seated, passes from the depression at 
the inner and back part of the external malleolus to a horizontal notch or depres- 
sion on the posterior surface of the astragalus. Its fibres are almost horizontal in 
direction. 
The middle fasciculus, the longest of the three, is a narrow rounded cord pass- 
ing from the apex of the external malleolus downward and slightly backward to 
the middle of the outer side of the os calcis. It is covered by the tendons of the 
Peroneus longus and brevis. 
The synovial membrane invests the inner surface of the ligaments, and sends 
a duplicature upward between the lower extremities of the tibia and fibula for a 
short distance. 
Relations.-The tendons, vessels, and nerves in connection with the joint are 
in front, from within outward, the Tibialis anticus, Extensor proprius pollicis, ante- 
rior tibial vessels, anterior tibial nerve, Ex- 
tensor longus digitorum, and Peroneus ter- 
tius; behind, from within outward, the Tibialis 
posticus, Flexor longus digitorum, posterior 
tibial vessels, posterior tibial nerve, Flexor 
longus pollicis; and in the groove behind the 
external malleolus the tendons of the Peroneus 
longus and brevis. 
The Arteries supplying the joint are de- 
rived from the malleolar branches of the ante- 
rior tibial and peroneal. 
The Nerves are derived from the anterior 
and posterior tibial. 
Actions.-The movements of the joint are 
mainly those of flexion and extension, but a 
certain amount of lateral motion is permitted 
when the foot is in the extended position. This 
is in consequence of the shape of the articular 
surface of the astragalus, which is considerably 
wider in front than behind (Fig. 233, p. 285), 
and of the tibio-fibular mortise, which is also 
broader in front than behind; hence in com- 
plete extension the narrowest part of the astrag- 
alus is lodged in the widest part of the tibio- 
fibular arch, and therefore a certain amount of 
lateral movement is possible. In the flexed position, on the other hand, the astrag- 
alus is tightly embraced by the two malleoli, and no lateral movement is possible. 
In extreme extension there is also a slight amount of adduction, or inward move- 
[Fig. 276. 
PERON| 
LONG. &tl, 
BREV. H 
I TIB. 
U- POST. 
FLEX 
j-DIG.LCNG 
MNT. PLANT 
FLEX. 
/LONG. POLL. 
/"•-ABDUCT 
' POLL. 
' EXT. PLANT. 
FLEX. DIG. 
BREV* 
Coronal Section of Ankle and Foot (Volz).] 
1 Humph ry on The Skeleton, p. 559. OF THE TARSUS. 
357 
ment of the fore part of the foot; this is in consequence of the external border of 
the upper articular surface of the astragalus being longer than the inner one and 
somewhat curved, which has a tendency to turn the foot inward if extension is car- 
ried to its extreme limit. Of the ligaments, the internal or deltoid is of very great 
power, so much so that it usually resists a force which fractures the process of bone to 
which it is attached. Its middle portion, together with the middle fasciculus of the 
external lateral ligament, binds the bones of the leg firmly to the foot and resists dis- 
placement in every direction. Its anterior and posterior fibres limit extension and 
flexion of the foot respectively, and the anterior fibres also limit abduction. The pos- 
terior portion of the external lateral ligament assists the middle portion in resisting 
the displacement of the foot backward, and deepens the cavity for the reception of the 
astragalus. The anterior fasciculus is a security against the displacement of the 
foot forward, and limits extension of the joint. The movements of abduction and 
adduction of . the foot, together with the minute changes in form by which it is 
applied to the ground or takes hold of an object in climbing, etc., are mainly 
[Fig. 277. 
□ ORS 
P£Dg 
PERON. 
LONG. \ 
\ 
ELANJaR v.&a. 
Sagittal Section of Ankle and Foot (Volz).] 
effected in the tarsal joints, the one which enjoys the greatest amount of motion 
being that between the astragalus and os calcis behind and the scaphoid and cuboid 
in front. This is often called the transverse [or medio-] tarsal joint, and it, with the 
subordinate joints of the tarsus, can replace the ankle-joint in a great measure 
when the latter has become ankylosed. 
Extension of the tarsal bones upon the tibia and fibula is produced by the Gas- 
trocnemius, Soleus, Tibialis posticus, Peroneus longus and brevis, Flexor longus 
digitorum, and Flexor longus pollicis; flexion, by the Tibialis anticus, Peroneus 
tertius, Extensor longus digitorum, and Extensor proprius pollicis;1 adduction, 
in the extended position, is produced by the Tibialis anticus and posticus; and 
abduction, by the Peronei. 
V. Articulations of the Tarsus. 
These articulations may be subdivided into three sets: 1, The articulations of 
the first row of tarsal bones; 2, the articulations of the second row of tarsal bones; 
3, the articulations of the two rows with each other. 
1 The student must bear in mind that the Extensor longus digitorum and Extensor proprius pollicis 
are extensors of the toes, but flexors of the ankle, and that the Flexor longus digitorum and Flexor lon- 
gus pollicis are flexors of the toes, but extensors of the ankle. 358 
ARTICULA TIONS. 
1. Articulations of the First Row of Tarsal Bones. 
The articulations between the astragalus and os calcis are two in number-ante- 
rior and posterior. They are arthrodial joints. The bones are connected together 
by three ligaments: 
External Calcaneo-astragaloid. 
Posterior Calcaneo-astragaloid. 
The External Calcaneo-astragaloid Ligament (Fig. 275, p. 355) is a short 
strong fasciculus passing from the outer surface of the astragalus, immediately 
beneath its external malleolar facet, to the outer surface of the os calcis. It is 
placed in front of the middle fasciculus of the external lateral ligament of the 
ankle-joint, with the fibres of which it is parallel. 
The Posterior Calcaneo-astragaloid Ligament (Fig. 274, p. 355) connects 
the posterior extremity of the astragalus with the upper contiguous surface of the 
os calcis; it is a short narrow band, the fibres of which are directed obliquely 
backward and inwTard. 
The Interosseous Ligament forms the chief bond of union between the bones. 
It consists of numerous vertical and oblique fibres attached by one extremity to the 
groove between the articulating surface of the astragalus; by the other to a corre- 
sponding depression on the upper surface of the os calcis. It is very thick and 
strong, being at least an inch in breadth from side to side, and serves to unite the 
os calcis and astragalus solidly together. 
The synovial membranes (Fig. 279) are two in number-one for the posterior 
calcaneo-astragaloid articulation ; a second for the anterior calcaneo-astragaloid joint. 
The latter synovial membrane is continued forward between the contiguous surfaces 
of the astragalus and scaphoid bones. 
Interosseous. 
The articulations between the scaphoid, cuboid, and three cuneiform are effected 
by the follow ing ligaments : 
2. Articulations of the Second Row of Tarsal Bones. 
Dorsal. 
Interosseous. 
Plantar. 
The Dorsal Ligaments are small bands of parallel fibres which pass from each 
bone to the neighboring bones, with which it articulates. 
The Plantar Ligaments have the same arrangement on the plantar surface. 
The Interosseous Ligaments are four in number. They consist of strong 
transverse fibres which pass between the rough non-articular surfaces of adjoining 
bones. There is one between the sides of the scaphoid and cuboid, a second between 
the internal and middle cuneiform bones, a third between the middle and external 
cuneiform, and a fourth between the external cuneiform and cuboid. The scaphoid 
and cuboid when in contact present each a small articulating facet covered w ith car- 
tilage, and lined either by a separate synovial membrane or by an offset from the 
great tarsal synovial membrane. 
3. Articulations of the Two Rows of the Tarsus with each other. 
These may be conveniently divided into three sets: the joint between the os 
calcis and the cuboid, the ligaments connecting the os calcis with the scaphoid, the 
joint between the astragalus and the scaphoid. 
The ligaments connecting the os calcis with the cuboid are foui' in number: 
Dorsal.. 
Superior Calcaneo-cuboid. 
Internal Calcaneo-cuboid (Interosseous). 
Plantar. 
Long Calcaneo-cuboid. 
Short Calcaneo-cuboid. OF THE TARSUS. 
359 
The Superior Calcaneo-cuboid Ligament (Fig. 275) is a thin and narrow fas- 
ciculus which passes between the contiguous surfaces of the os calcis and cuboid on 
the dorsal surface of the joint. 
The Internal Calcaneo-cuboid (Interosseous) Ligament (Fig. 275) is a short 
but thick and strong band of fibres arising from the os calcis in the deep hollow 
which intervenes between it and the astragalus, and closely blended at its origin 
with the superior calcaneo-scaphoid ligament. It is inserted into the inner side of 
the cuboid bone. This ligament forms one of the chief bonds of union between 
the first and second row of the tarsus. 
The Long Calcaneo-cuboid (Fig. 278), the more superficial of the two plantar 
ligaments, is the longest of all the ligaments of the tarsus: it is attached to the 
under surface of the os calcis, from near the tuberosities, as far forward as the ante- 
rior tubercle ; its fibres pass forward to be attached to the ridge on the under surface 
of the cuboid bone, the more superficial fibres being continued onward to the bases 
of the second, third, and fourth metatarsal bones. This ligament crosses the groove 
on the under surface of the cuboid bone, converting it into a canal for the passage 
of the tendon of the Peroneus longus. 
The Short Calcaneo-cuboid Ligament lies nearer to the bones than the preced- 
ing, from which it is separated by a little 
areolar adipose tissue. It is exceedingly 
broad, about an inch in length, and extends 
from the tubercle and the depression in front 
of it on the fore part of the under surface of 
the os calcis to the inferior surface of the 
cuboid bone behind the peroneal groove. A 
separate synovial membrane is found in the 
calcaneo-cuboid articulation. 
The ligaments connecting the os calcis 
with the scaphoid are two in number: 
Fig. 278. 
Superior Calcaneo-scaphoid. 
Inferior Calcaneo-scaphoid. 
The Superior Calcaneo-scaphoid (Fig. 
275) arises, as already mentioned, with the 
internal calcaneo-cuboid in the deep hollow 
between the astragalus and os calcis; it passes 
forward from the inner side of the anterior ex- 
tremity of the os calcis to the outer side of 
the scaphoid bone. These two ligaments re- 
semble the letter Y, being blended together 
behind, but separated in front. 
The Inferior Calcaneo-scaphoid (Fig. 
278) is by far the larger and stronger of the 
two ligaments of this articulation: it is a 
broad and thick band of fibres, which passes 
forward and inward from the interior and in- 
ner extremity of the os calcis to the under 
surface of the scaphoid bone. This liga- 
ment not only serves to connect the os calcis 
and scaphoid, but supports the head of the 
astragalus, forming part of the articular 
cavity in which it is received. The upper 
surface is lined by the synovial membrane 
continued from the anterior calcaneo-astragaloid articulation. Its under surface 
is in contact with the tendon of the Tibialis posticus muscle.1 
Ligaments of Plantar Surface of the Foot. 
1 Mr. Hancock describes an extension of this ligament upward on the inner side of the foot, 
which completes the socket of the joint in that direction {Lancet, 1866, vol. i. p. 618). 360 
ARTICULA TIONS. 
The articulation between the astragalus and scaphoid is an arthrodial joint, the 
rounded head of the astragalus being received into the concavity formed by the 
posterior surface of the scaphoid, the anterior articulating surface of the calcaneum, 
and the upper surface of the calcaneo-scaphoid ligament, which fills up the trian- 
gular interval between those bones. The only ligament of this joint is the superior 
astragalo-scaphoid, a broad band which passes obliquely forward from the neck of 
the astragalus to the superior surface of the scaphoid bone. It is thin and weak 
in texture, and covered by the Extensor tendons. The inferior calcaneo-scaphoid 
supplies the place of an inferior ligament. 
The synovial membrane which lines the joint is continued forward from the 
anterior calcaneo-astragaloid articulation. This articulation permits of consider- 
able mobility, but its feebleness is such as to allow occasionally of dislocation of 
the astragalus. 
Actions.-The movements permitted between the bones of the first row, the 
astragalus, and os calcis are limited to a gliding upon each other from before back- 
ward and from side to side. The gliding movement which takes place between the 
bones of the second row is very slight, the articulation between the scaphoid and 
cuneiform bones being more movable than those of the cuneiform with each other 
and with the cuboid. The movement which takes place between the two rows is 
more extensive, and consists in a sort of rotation by means of which the sole of the 
foot may be slightly flexed and extended and carried inward and outward. 
VI. Tarsometatarsal Articulations. 
These are arthrodial joints. The bones entering into their formation are four 
tarsal bones-viz. the internal, middle, and external cuneiform, and the cuboid- 
which articulate with the metatarsal bones of the five toes. The metatarsal bone 
of the great toe articulates with the internal cuneiform; that of the second is 
deeply wedged in between the internal and external cuneiform, resting against the 
middle cuneiform, and being the most strongly articulated of all the metatarsal 
bones; the third metatarsal articulates with the extremity of the external cunei- 
form ; the fourth with the cuboid and external cuneiform; and the fifth with the 
cuboid. The articular surfaces are covered with cartilage lined by synovial mem- 
brane, and connected together by the following ligaments: 
Dorsal. 
Interosseous. 
Plantar. 
The Dorsal Ligaments consist of strong, flat, fibrous bands which connect the 
tarsal with the metatarsal bones. The first metatarsal is connected to the internal 
cuneiform by a single broad, thin, fibrous band; the second has three dorsal liga- 
ments, one from each cuneiform bone; the third has one from the external cunei- 
form ; and the fourth and fifth have one each from the cuboid. 
The Plantar Ligaments consist of longitudinal and oblique fibrous bands con- 
necting the tarsal and metatarsal bones, but disposed with less regularity than on 
the dorsal surface. Those for the first and second metatarsal are the most strongly 
marked; the second and third metatarsal receive strong fibrous bands, which pass- 
obliquely across from the internal cuneiform; the plantar ligaments of the fourth 
and fifth metatarsal consist of a few scanty fibres derived from the cuboid. 
The Interosseous Ligaments are three in number-internal, middle, and exter- 
nal. The interned one passes from the outer extremity of the internal cuneiform to 
the adjacent angle of the second metatarsal. The middle one, less strong than the 
preceding, connects the external cuneiform with the adjacent angle of the second 
metatarsal. The external interosseous ligament connects the outer angle of the 
external cuneiform with the adjacent side of the third metatarsal. 
The synovial membranes (Fig- 279) found in the articulations of the tarsus 
and metatarsus are six in number-one for the posterior calcaneo-astragaloid artic- 
ulation ; a second for the anterior calcaneo-astragaloid and astragalo-scaphoid artic- METATARSO-PHALANGEAL ARTICULATIONS. 
361 
ulations; a third for the calcaneo-cuboid articulation ; a fourth for the articulations 
of the scaphoid with the three cuneiform, the three cuneiform with each other, the 
external cuneiform with the cuboid, and the middle and external cuneiform with 
the bases of the second and third metatarsal bones; a fifth for the metatarsal bone 
Fig. 279. 
Oblique Section of the Articulations of the Tarsus and Metatarsus, showing the six synovial membranes. 
of the great toe and the internal cuneiform; and a sixth for the fourth and fifth 
metatarsal bones with the cuboid. A small synovial membrane is sometimes found 
between the contiguous surfaces of the scaphoid and cuboid bones. 
Articulations of the Metatarsal Bones with each other. 
The bases of the metatarsal bones, except the first, are connected together by 
dorsal, plantar, and interosseous ligaments. The dorsal and plantar ligaments pass 
from one metatarsal bone to another. The interosseous ligaments lie deeply between 
the rough, non-articular portions of the lateral surfaces. The articular surfaces are 
covered with cartilage, and provided with synovial membrane continued forward 
from the tarso-metatarsal joints. The digital extremities of the metatarsal bones 
are united by the transverse metatarsal ligament. It connects the great toe with 
the rest of the metatarsal bones, and in this respect differs from the transverse 
ligament in the hand, which does not extend to the metacarpal bone of the thumb. 
Actions.-The movement permitted in the tarsal ends of the metatarsal bones 
is limited to a slight gliding of the articular surfaces upon one another; consider- 
able motion, however, takes place in the digital extremities. 
VII. Metatarso-phalangeal Articulations. 
The heads of the metatarsal bones are connected with the concave articular sur- 
faces of the first phalanges by the following ligaments: 
Plantar. 
Two Lateral. 
Their arrangement is precisely similar to the corresponding parts in the hand. 
The expansion of the Extensor tendon supplies the place of a dorsal ligament. 
Actions.-The movements permitted in the metatarso-phalangeal articulations 
are flexion, extension, abduction, and adduction. 
VUI. Articulations of the Phalanges. 
The ligaments of these articulations are similar to those found in the hand, each 
pair of phalanges being connected by a plantar and two lateral ligaments, and their 
articular surfaces lined by synovial membrane. Their actions are also similar. The Muscles and Fasciae.1 
THE Muscles are connected with the bones, cartilages, ligaments, and skin, either 
directly or through the intervention of fibrous structures called tendons or apo- 
neuroses. Where a muscle is attached to bone or cartilage the fibres terminate in 
blunt extremities upon the periosteum or perichondrium, and do not come into direct 
relation with the osseous or cartilaginous tissue. Where muscles are connected with 
the skin, they either lie as a flattened layer beneath it or are connected with its 
areolar tissue by larger or smaller bundles of fibres, as in the muscles of the face. 
The muscles vary extremely in their form. In the limbs they are of consider- 
able length, especially the more superficial ones, the deep ones being generally broad; 
they surround the bones and form an important protection to the various joints. In 
the trunk they are broad, flattened, and expanded, forming the parietes of the cav- 
ities which they enclose; hence the reason of the terms long, broad, short, etc. used 
in the description of a muscle. 
There is a considerable variation in the arrangement of the fibres of certain mus- 
cles with reference to the tendons to which they are attached In some the fibres 
are arranged longitudinally and terminate at either end in a narrow tendon. If the 
fibres converge, like the plumes of a pen, to one side of a tendon which runs the 
entire length of a muscle, the muscle is said to be penniform, as the Peronei; if they 
converge to both sides of the tendon, the muscle is called bipenniform, as the Rectus 
femoris; if they converge from a broad surface to a narrow tendinous point, the 
muscle is said to be radiated, as the Temporal and Glutei muscles. 
[The arrangement of the muscular fibres in respect of their attachment to the 
tendons of origin and insertion is a matter of great importance as to their relative 
strength and range of contraction. Thus in Fig. 280 A, the muscular belly, M, 
is a direct continuation of the tendons, and the length of the muscular belly is the 
same as that of the individual fibres. In b and c the muscular bellies arise from 
aponeuroses on their surfaces, but the arrangement of the fibres is very different. 
In B the fibres are many and short; the fibres arising from the upper end of one 
aponeurosis are inserted into the upper end of the other aponeurosis, and vice versd. 
In this case the muscular belly a to b is apparently long, but the individual fibres 
are short, but very many, thus giving great power and short range, as in the Tri- 
ceps, the hamstrings, etc. In C the muscular belly is of the same shape and length 
as in b, but the muscular fibres, while they are comparatively few, are nearly as long 
as the belly, giving great range, with lessened strength. In D the upper tendon 
penetrates the tissue of the muscle, as in the Rectus femoris, and the short muscular 
fibres are inserted into aponeuroses which terminate in the lower tendon, and again 
give great power and short range.] 
They differ no less in size: the Gastrocnemius forms the chief bulk of the back 
of the leg, and the fibres of the Sartorius are nearly two feet in length, whilst the 
Stapedius, a small muscle of the internal ear, weighs about a grain and its fibres are 
not more than two lines in length. 
[It is worthy of note that in the well-nourished living mode] the projecting 
bony points of the skeleton-e. g. great trochanter, vertebral spines, etc-are rep- 
1 The Muscles and Fasciae are described conjointly, in order that the student may consider the 
arrangement of the latter in his dissection of the former. It is rare for the student of anatomy in 
this country to have the opportunity of dissecting the fasciae separately; and it is for this reason, as 
well as from the close connection that exists between the muscles and their investing sheaths, that 
thev are considered together. Some general observations are first made on the anatomy of the mus- 
cles" and fasciae, the special description being given in connection with the different regions. 
362 MUSCLES AND FASCIAL. 
363 
resented by depressions instead of projections. The reason for this is the bulk of 
the neighboring muscles, which usually arise by small tendons from such bony 
prominences, the tendons quickly giving place to the large muscular bellies. In 
very thin persons this rule is reversed, the skeleton forms showing, while in long 
sickness the wasting of these muscles and the fat reproduces the bony prominences 
of the skeleton and leads to bed-sores.] 
The names applied to the various muscles have been derived-1, from their situ- 
ation, as the Tibialis, Radialis, Ulnaris, Peroneus; 2, from their direction, as the 
Rectus abdominis, Obliqui capitis, Transversalis; 3, from their uses, as Flexors, 
[Fig. 280. 
Arrangement of Muscular Fibres in Muscles in relation to the tendons and muscular aponeuroses: t, t', tendons 
of origin and insertion; M, muscular belly; a, b, length of muscular belly (Beaunis and Bouchard).] 
Extensors, Abductors, etc.; 4, from their shape, as the Deltoid, Trapezius, Bhom- 
boideus ; 5, from the number of their divisions, as the Biceps, the Triceps ; 6, from 
their points of attachment, as the Sterno-cleido-mastoid, Sterno-hyoid, Sterno-thy- 
roid. [In the Latin names of the muscles it must be remembered that the word 
"musculus" always is supposed to precede the remainder of the name, which con- 
sists really of one or more adjectives qualifying this name. Many of these, how- 
ever, are abbreviated, as "Sterno-hyoid" for "musculus sterno-hyoideus."] 
In the description of a muscle the term origin is meant to imply its more [usu- 
ally] fixed or central attachment, and the term insertion the movable point to which 
the force of the muscle is directed; but the origin is absolutely fixed in only a very 
small number of muscles, such as those of the face, which are attached by one extrem- 
ity to the bone and by the other to the movable integument; in the greater number 
the muscle can be made to act from either extremity. 
[To ascertain the action of any single muscle, the best means is to apply elec- 
tricity to it on the living model. (See figures at the end of the section on the Mus- 
cles.) On the cadaver any motion which relaxes the muscle represents its active 
contraction, while any which makes it tense is the reverse of its action.] 
In the dissection of the muscles the student should pay especial attention to the 
exact origin, insertion, and actions of each, and its more important relations with 
surrounding parts. An accurate knowledge of the points of attachment of the 
muscles is of great importance in the determination of their action. By a know- 
ledge of the action of the muscles the surgeon is able to explain the causes of dis- 
placement in various forms of fracture and the causes which produce distortion in 
various deformities, and consequently to adopt appropriate treatment in each case. 
The relations also of some of the muscles, especially those in immediate apposition 
with the larger blood-vessels, and the surface-markings they produce, should be 364 
MUSCLES AND FASCIAE. 
especially remembered, as they form useful guides in the application of a ligature to 
those vessels. [After dissecting superficial muscles, it is often desirable to cut 
them, so as to reach the deeper structures. In doing so it is better not to cut them 
at their origin or insertion, but somewhere near the middle, so that the origin and 
insertion may be the better studied after more thorough dissection. If a number 
of muscles lie together, as in the forearm, cut them at different levels, so that the 
upper and lower portions may be the better recognized. 
It is especially recommended to the student not to dissect the muscles of the/ace 
and perineum until he has dissected those of other parts of the body, as these 
muscles present peculiarities which make their dissection very difficult. (See p. 
365 and the Perineum.)] 
Tendons are white, glistening, fibrous cords varying in length and thickness, 
sometimes round, sometimes flattened, of considerable strength, and devoid of elas- 
ticity. They consist almost entirely of white fibrous tissue, the fibrils of which 
have an undulating course parallel with each other and are firmly united together. 
They are very sparingly supplied with blood-vessels, the smaller tendons presenting 
in their interior not a trace of them. Nerves also are not present in the smaller 
tendons; but the larger ones, as the tendo Achillis, receive nerves which accom- 
pany the nutrient vessels. The tendons consist principally of a substance which 
yields gelatin. 
[Remarkable changes occur in the muscles with age. In childhood the muscu- 
lar bellies are relatively long and the tendons short. With advancing years the 
tendons invade the muscular bellies, so that the contractile element is a constantly 
diminishing factor. This accounts for the greater agility and suppleness of youth, 
which as we get older is lost to such a degree that professional acrobats well know 
that to excel in such athletic feats it is needful to begin in childhood and to prac- 
tise these feats constantly. A baby can readily put its feet in its mouth, or when 
sitting on a bed with the legs at right angles with the body can easily lift the legs 
to an acute angle with the trunk-a feat that is impossible with an adult, since the 
ligamentous action of the muscles (p. 301) has been increased by the preponderance 
of the tendon over the muscular belly. These natural limitations of motion are 
always to be considered by the surgeon when making passive motion.] 
Aponeuroses are flattened or ribbon-shaped tendons of a pearly-white color, 
iridescent, glistening, and similar in structure to the tendons. They are destitute 
of nerves, and the thicker ones are only sparingly supplied with blood-vessels. 
The tendons and aponeuroses are connected, on the one hand, with the muscles, 
and on the other hand with the movable structures, as the bones, cartilages, liga- 
ments, fibrous membranes (for instance, the sclerotic), and the synovial membranes 
(subcrureus, subanconeus). Where the muscular fibres are in a direct line with 
those of the tendon or aponeurosis, the two are directly continuous, the muscular 
fibre being distinguishable from that of the tendon only by its striation. But 
where the muscular fibre joins the tendon or aponeurosis at an oblique angle, the 
former terminates, according to Kdlliker, in rounded extremities, which are received 
into corresponding depressions on the surface of the latter, the connective tissue 
between the fibres being continuous with that of the tendon. The latter mode of 
attachment occurs in all the penniform and bipenniform muscles, and in those mus- 
cles the tendons of which commence in a membranous form, as the Gastrocnemius 
and Soleus. 
Thefascice (fascia, a bandage) are fibro-areolar or aponeurotic laminae of variable 
thickness and strength, found in all regions of the body, investing the softer and more 
delicate organs. The fasciae have been subdivided, from the situation in which they 
are found, into two groups, superficial and deep. 
The superficial fascia is found immediately beneath the integument over almost 
the entire surface of the body. It connects the skin with the deep or aponeurotic 
fascia, and consists of fibro-areolar-tissue, containing in its meshes follicles of fat 
in varying quantity. In the eyelids and scrotum, where adipose tissue is rarely 
deposited, this tissue is very liable to serous infiltration. The superficial fascia OF THE CRANIUM AND FACE. 
365 
varies in thickness in different parts of the body: in the groin it is so thick as to 
be capable of being subdivided into several laminae, but in the palm of the hand it 
is of extreme thinness and intimately adherent to the integument. The superficial 
fascia is capable of separation into two or more layers, between which are found the 
superficial vessels and nerves [the mammary gland] and the superficial lymphatic 
glands, as the superficial epigastric vessels in the abdominal region, the radial and 
ulnar veins in the forearm, the saphenous veins in the leg and thigh : certain cuta- 
neous muscles also are situated in the superficial fascia, as the Platysma myoides in 
the neck and the Orbicularis palpebrarum around the eyelids. This fascia is most 
distinct at the lower part of the abdomen, the scrotum, perineum, and extremities; 
is very thin in those regions where muscular fibres are inserted into the integument, 
as on the side of the neck, the face, and around the margin of the anus; and is 
almost entirely wanting in the palms of the hands and soles of the feet, where the 
integument is adherent to the deep fascia. 
The superficial fascia connects the skin to the subjacent parts, facilitates the 
movement of the skin, serves as a soft nidus for the passage of vessels and nerves 
to the integument, and retains the warmth of the body, since the adipose tissue con- 
tained in its areolae is a bad conductor of caloric. 
The deep fascia is a dense, inelastic, unyielding fibrous membrane, forming 
•sheaths for the muscles and affording them broad surfaces for attachment. It con- 
sists of shining tendinous fibres placed parallel with one another and connected 
together by other fibres disposed in a rectilinear manner. It is usually exposed on 
the removal of the superficial fascia, forming a strong investment, which not only 
binds down collectively the muscles in each region, but gives a separate sheath to 
•each, as well as to the vessels and nerves. The fasciae are thick in unprotected 
.situations, as on the outer side of a limb, and thinner on its inner side. The 
deep fasciae assist the muscles in their action by the degree of tension and pressure 
they make upon the surface; and in certain situations this is increased and regu- 
lated by muscular action, as, for instance, by the Tensor vaginae femoris and Glu- 
teus maximus in the thigh, by the Biceps in the leg, and the Palmaris longus in the 
hand. In the limbs the fasciae not only invest the entire limb, but give off septa 
which separate the various muscles and are attached beneath to the periosteum: 
these prolongations of fasciae are usually spoken of as intermuscular septa. 
The Muscles and Fasciae may be arranged, according to the general division of 
the body, into those of the cranium, face, and neck, those of the trunk, those of 
?the upper extremity, and those of the lower extremity. 
MUSCLES AND FASCLZE OF THE CRANIUM AND PACE. 
[The muscles of the face may be divided into two classes: the muscles of 
Expression, supplied by the seventh nerve, and the muscles of Mastication (Mas- 
seter, Temporal, and Pterygoids), supplied by the fifth nerve. The muscles of 
expression differ from those of the body in general in several particulars. They 
do not go from bone to bone, but from bone to soft parts, and in the sphincters of 
the mouth and eyelids, as is the case in all sphincter muscles, the connection to the 
bone is very slight. They have no proper tendons of origin or insertion, as a rule. 
They have no muscular sheath, and are very loose in texture (compare Fig. 284), 
the fibres being intermingled with fatty and fibrous tissue. Frequently, fibres 
beginning in one muscle, especially those at its periphery, pass into another muscle, 
thus modifying greatly the action of both. They vary in development, not only from 
person to person, and so vary the expression; but also in the same person at differ- 
ent ages, and on the two sides of the face great variations occur which influence 
the expression. Sir Charles Bell's and Darwin's works on Expression should be 
■carefully read by the student who desires to understand them well.] 
The muscles of the cranium and face consist of ten groups, arranged according 
to the region in which they are situated: MUSCLES AND FASCIAE. 
366 
1. Cranial Region. 
2. Auricular Region. 
3. Palpebral Region. 
4. Orbital Region. 
5. Nasal Region. 
6. Superior Maxillary Region. 
7. Inferior Maxillary Region. 
8. Intermaxillary Region. 
9. Temporo-maxillary Region. 
10. Pterygo-maxillary Region. 
The muscles contained in each of these groups are the following: 
1. Cranial Region. 
Occipito-frontalis. 
2. Auricular Region. 
Attollens aurem. 
Attrahens aurem. 
Retrahens aurem. 
3. Palpebral Region. 
Orbicularis palpebrarum. 
Corrugator supercilii. 
Tensor tarsi. 
4. Orbital Region. 
Levator palpebrae. 
Rectus superior. 
Rectus inferior. 
Rectus internus. 
Rectus externus. 
Obliquus superior. 
Obliquus inferior. 
5. Nasal Region. 
Pyramidalis nasi. 
Levator labii superioris alaeque nasi. 
Dilatator naris posterior. 
Dilatator naris anterior. 
Compressor nasi. 
Compressor narium minor. 
Depressor ahe nasi. 
6. Superior Maxillary Region. 
Levator labii superioris. 
Levator anguli oris. 
Zygomaticus major. 
Zygomaticus minor. 
7. Inferior Maxillary Region. 
Levator labii inferioris. 
Depressor labii inferioris. 
Depressor anguli oris. 
8. Intermaxillary Region. 
Buccinator. 
Risorius. 
Orbicularis oris. 
9. Temporo-maxillary Region. 
Masseter. 
Temporal. 
10. Pterygo-maxillary Region. 
Pterygoideus externus. 
Pterygoideus internus. 
1. Cranial Region. 
Occipito-frontalis. 
Dissection (Fig. 281).-The head being shaved and a block placed beneath the back of the 
neck, make a vertical incision through the skin from before backward, commencing at the root, 
of the nose in front and terminating behind at the occipital protuberance ; make a second incis- 
ion in a horizontal direction along the forehead and round the side of the head from the anterior 
to the posterior extremity of the preceding. Raise the skin in front from the subjacent muscle 
from below upward: this must be done with extreme care, removing the integument from the: 
outer surface of the vessels and the nerves which lie between the two. 
The Superficial Fascia in the cranial region is a firm, dense layer, intimately 
adherent to the integument and to the Occipito-frontalis and its tendinous aponeur- 
osis ; it is continuous behind with the superficial fascia at the back part of the neck,, 
and laterally is continued over the temporal fascia. 
The Occipito-frontalis (Figs. 282, 284) is a broad musculo-fibrous layer which 
covers the whole of one side of the vertex of the skull from the occiput to the eyebrow. 
It consists of two muscular slips separated by an intervening tendinous aponeurosis. 
The occipital portion, thin, quadrilateral in form, and about an inch and a half in 
length, arises from the outer two-thirds of the superior curved line of the occipital 
bone and from the mastoid portion of the temporal. Its fibres of origin are tendin- 
ous, but they soon become muscular, and ascend in a parallel direction to termi- CRANIAL REGION. 
367 
nate in the tendinous aponeurosis. The fronted portion is thin, of a quadrilateral 
form, and intimately adherent to the skin. It is broader, its fibres are longer, and 
their structure paler than the occipital portion. Its internal fibres are continuous 
with those of the pyramidalis nasi. Its middle fibres become blended with the Cor- 
rugator supercilii and Orbicularis palpebrarum, and the outer fibres are also blended 
with the latter muscle over the external angular process. According to Theile, the 
innermost fibres are attached to the nasal bones, the outer to the external angular 
process of the frontal bone. From this attachment the fibres are directed upward 
and join the aponeurosis below the coronal suture. The inner margins of the frontal 
portions of the two muscles are joined together for some distance above the root of 
Fig. 281. 
/ DisscctioTioJ'szM.v 
2.3. of AURICULAR RECION 
G.of FACE 
J. 8- of NECW 
Dissection of the Head, Face, and Neck. 
the nose; but between the occipital portions there is a considerable though variable 
interval which is occupied by the aponeurosis. 
The aponeurosis \_galea capitis] covers the upper part of the vertex of the 
skull, being continuous in the middle line with the aponeurosis of the opposite 
muscle. Behind it is attached, in the interval between the occipital origins, to the 
occipital protuberance and superior curved lines above the attachment of the Tra- 
pezius ; in front it forms a short angular prolongation between the frontal portions; 
and on each side it has connected with it the Attollens and Attrahens aurem mus- 
cles : in this situation it loses its aponeurotic character, and is continued over the 
temporal fascia to the zygoma as a layer of laminated areolar tissue. This apo- 
neurosis is closely connected to the integument by a dense fibro-cellular tissue which 
contains much granular fat, and in which ramify the numerous vessels and nerves 
of the integument; it is loosely connected with the pericranium by a quantity of 
loose cellular tissue which allows of a considerable degree of movement of the 
integument. 
Nerves.-The frontal portion of the Occipito-frontalis is supplied by the facial 
nerve, its occipital portion by the posterior auricular branch of the facial, and 
sometimes by the occipitalis minor. 
Actions.-The frontal portion of the muscle raises the eyebrows and the skin 
over the root of the nose, and at the same time draws the scalp forward, throwing 
the integument of the forehead into transverse wrinkles. The posterior portion 
draws the scalp backward. By bringing alternately into action the occipital and 
frontal portions the entire scalp may be moved forward and backward. In the 
ordinary action of the muscles the eyebrows are elevated and at the same time 
the aponeurosis is fixed by the posterior portion, thus giving to the face the expres- 
sion of surprise: if the action is more exaggerated, the eyebrows are still farther 368 
MUSCLES AND FASCIAE. 
Fig. 282. 
CORRUGATOR SUPERCILIl- 
DILATOR NARIS ANTER-? 
DILATOR NARIS POSTER- 
COMPRESSOR WAR IUM MINOR - 
DEPRSGSOR AML NASI- 
LEVATOR MENTI- 
Muscles of the Head, Face, and Neck. 
raised and the skin of the forehead thrown into transverse wrinkles, as in the expres- 
sion of fright or horror. [On lifting the eyebrows, the line where the frontal belly 
joins the aponeurosis is easily seen. This is usually not a horizontal line, but curved 
like the wrinkles of the forehead. These wrinkles, when typical, are curved thus 
(Fig. 283), 1 being the central member of the 
curve above the nose; 2, 2, the lateral mem- 
bers above the eyebrows. From this type 
they vary, and in some persons become straight 
lines. Either the central or the lateral por- 
tions may be poorly marked or even absent. 
If the central portion be lost, the lateral often 
meet, or even cross each other. These variations in type, development, and number 
produce the most diverse results in expression and are very important to the artist. 
Their number depends on the thickness of the skin: the thicker the skin the 
[Fig. 283. 
Typical Wrinkle in Forehead : 1, central: 2, 2, 
lateral portions of the curve.-W. W. K.] AURICULAR REGION. 
369 
fewer the wrinkles. In early childhood the skin of the forehead can always be 
elevated in mass, but it is seldom distinctly wrinkled before six years of age, and 
sometimes not till eleven.] 
2. Auricular Region (Fig. 282). 
Attollens aurem. 
Attrahens aurem. 
Retrahens aurem. 
These three small muscles are placed immediately beneath the skin around the 
external ear. In man, in whom the external ear is almost immovable, they are 
rudimentary. They are the analogues of large and important muscles in some of 
the Mammalia. 
Dissection.-This requires considerable care, and should be performed in the following man- 
ner : To expose the Attollens aurem : draw the pinna or broad part of the ear downward, when 
a tense band will be felt beneath the skin passing from the side of the head to the upper part of 
the concha; by dividing the skin over the tendon in a direction from below upward, and then 
reflecting it on each side, the muscle is exposed. To bring into view the Attrahens aurem, draw 
the helix backward by means of a hook, when the muscle will be made tense, and may be 
exposed in a similar manner to the preceding. To expose the Retrahens aurem, draw the pinna 
forward, when the muscle, being made tense, may be felt beneath the skin at its insertion into 
the back part of the concha, and may be exposed in the same manner as the other muscles. 
The Attollens aurem (Auricularis superior), the largest of the three, is thin 
and fan-shaped: its fibres arise from the aponeurosis of the Occipito-frontalis, and 
converge to be inserted by a thin, flattened tendon into the upper part of the cranial 
surface of the pinna. 
Relations.-Externally, with the integument; internally, with the temporal 
fascia and the areolar layer derived from the aponeurosis. 
The Attrahens aurem (Auricularis anterior), the smallest of the three, is thin-, 
fan-shaped, and its fibres pale and indistinct; they arise from the lateral edge of 
the aponeurosis of the Occipito-frontalis, and converge to be inserted into a projec- 
tion on the front of the helix. 
Relations.-Externally, with the skin; internally, with the temporal fascia 
which separates it from the temporal artery and vein. 
The Retrahens aurem (Auricularis posterior) consists of two or three fleshy 
fasciculi which arise from the mastoid portion of the temporal bone by short apo- 
neurotic fibres. They are inserted into the lower part of the cranial surface of 
the concha. 
Relations.-Externally, with the integument; internally, with the mastoid 
portion of the temporal bone. 
Nerves.-The Attollens aurem is supplied by the occipitalis minor; the Attra- 
hens aurem, by the facial; and the Retrahens aurem, by the posterior auricular 
branch of the facial. 
Actions.-In man these muscles possess very little action ; the Attollens aurem 
slightly raises the ear; the Attrahens aurem draws it forward and upward; and the 
Retrahens aurem draws it backward. [Many persons can move the ear upward and 
backward, and most people do so to a slight but perceptible extent in smiling and 
laughter.] 
3. Palpebral Region (Figs. 282, 284). 
Orbicularis palpebrarum. 
Corrugator supercilii. 
Levator palpebrae. 
Tensor tarsi. 
Dissection (Fig. 281).-In order to expose the muscles of the face, continue the longitudinal 
incision, made in the dissection of the Occipito-frontalis, down the median line of the face to the 
tip of the nose, and from this point onward to the upper lip, and carry another incision along 
the margin of the lip to the angle of the mouth, and transversely across the face to the angle of 
the jaw. Then make an incision in front of the external ear from the angle of the jaw upward, 
to join the transverse incision made in exposing the Occipito-frontalis. These incisions include 
a square-shaped flap, which should be removed with care in the direction marked in the figure, 
as the muscles at some points are intimately adherent to the integument. 370 
MUSCLES AND FASCIAE. 
The Orbicularis palpebrarum is a sphincter muscle which surrounds the cir- 
cumference of the orbit and eyelids. It arises from the internal angular process 
of the frontal bone, from the nasal process of the superior maxillary in front of the 
lachrymal groove, and from the 
anterior surface and borders of 
a short tendon, the tendo palpe- 
brarum, placed at the inner an- 
gle of the orbit. From this ori- 
gin the fibres are directed out- 
ward, forming a broad, thin, 
and flat layer which covers the 
eyelids, surrounds the circum- 
ference of the orbit, and spreads 
out over the temple and down- 
ward on the cheek, becoming 
blended with the Occipito-fron- 
talis and Corrugator supercilii. 
The palpebral portion (ciliaris) 
of the Orbicularis is thin and 
pale; it arises from the bifur- 
cation of the tendo palpebrarum, 
and forms a series of concentric 
curves which are united on the 
outer side of the eyelids at an 
acute angle by a cellular raphe, 
some being inserted into the 
external tarsal ligament and 
malar bone. The orbicular por- 
tion (orbicularis latus) is thicker and of a reddish color: its fibres are well devel- 
oped and form complete ellipses. 
Relations.-By its superficial surface with the integument; by its deep surface 
with the Occipito-frontalis and Corrugator supercilii, with which it is inti- 
mately blended, and with the supraorbital vessels and nerve; below it covers the 
lachrymal sac and the origin of the Levator labii superioris and the Levator labii 
superioris alseque nasi muscles. Internally, it is occasionally blended with the 
Pyramidalis nasi; externally, it lies on the temporal fascia. On the eyelids it is 
separated from the conjunctiva by a fibrous membrane and the so-called tarsal 
cartilage.1 
The tendo palpebrarum (tendo oculi) is a short tendon, about two lines in length 
and one in breadth, attached to the nasal process of the superior maxillary bone in 
front of the lachrymal groove. Crossing the lachrymal sac, it divides into two parts, 
each division being attached to the inner extremity of the corresponding tarsal car- 
tilage. As the tendon crosses the lachrymal sac a strong aponeurotic lamina is 
given off from the posterior surface, which expands over the sac and is attached 
to the ridge on the lachrymal bone. This is the reflected aponeurosis of the tendo 
palpebrarum. 
The Corrugator supercilii' is a small, narrow, pyramidal muscle placed at the 
inner extremity of the eyebrow, beneath the Occipito-frontalis and Orbicularis pal- 
pebrarum muscles. It arises from the inner extremity of the superciliary ridge, 
whence its fibres pass upward and outward to be inserted into the under surface of 
the orbicularis opposite the middle of the orbital arch. 
Relations.-By its anterior surface with the Occipito-frontalis and Orbicularis 
palpebrarum muscles; by its posterior surface with the frontal bone and supra- 
trochlear nerve. 
[Fig. 284. 
CORPUS.. 
SUPERC1L. 
PYRAM. 
NASI. 
TEN DO. 
PALP. 
Frontal and Ocular Muscles, showing their loose texture and inter- 
mingling fibres when minutely dissected (Henle).] 
1 The student should bear in mind that the tarsal cartilages do not really consist of cartilaginous 
tissue and that therefore the name is a bad one; it has, however, been sanctioned by such long usage 
that it seems inexpedient to alter it, since it might lead to confusion. ORBITAL REGION. 
371 
The Levator palpebrse will be described with the muscles of the orbital region. 
The Tensor tarsi [Horner's muscle] is a small thin muscle, about three lines in 
breadth and six in length, situated at the inner side of the orbit, behind the tendo 
oculi. It arises from the crest and adjacent part of the orbital surface of the lach- 
rymal bone, and, passing across the lachrymal sac, divides into two slips, which cover 
the lachrymal canals and are inserted into the tarsal cartilages near the puncta lach- 
rymalia. Its fibres appear to be continuous with those of the palpebral portion of 
the Orbicularis; it is occasionally very indistinct. 
Nerves.-The Orbicularis palpebrarum, Corrugator supercilii, and Tensor tarsi 
are supplied by the facial nerve. 
Actions.-The Orbicularis palpebrarum is the sphincter muscle of the eyelids. 
The palpebral portion acts [for the most part] involuntarily in closing the lids and 
independently of the orbicular portion, which is subject to the will. The palpe- 
bral portion closes the eyelids gently, as in sleep or in blinking; the entire muscle, 
when brought into action, brings the lids into close contact, as in photophobia. The 
skin of the forehead, temple, and cheek is then drawn inward toward the inner angle 
of the eye, and is thrown into folds, especially radiating from the outer angle of the 
eyelids, which give rise in old age to the so-called "crow's feet." The Levator pal- 
pebrge is the direct antagonist of this muscle; it raises the upper eyelid and exposes 
the globe. The Corrugator supercilii draws the eyebrow downward and inward, pro- 
ducing the vertical wrinkles of the forehead. It is the "frowning" muscle, and 
may be regarded as the principal agent in the expression of suffering. [These ver- 
tical wrinkles are above the nose, and vary to a moderate extent in number and 
degree. In marked contrast to the transverse wrinkles, I have never seen a child, 
even a baby, who could not produce these wrinkles and frown.] The Tensor tarsi 
draws the eyelids and the extremities of the lachrymal canals inward and compresses 
them against the surface of the globe of the eye, thus placing them in the most 
favorable situation for receiving the tears. It serves also to compress the lach- 
rymal sac. 
4. Orbital Region (Fig. 285). 
Levator palpebrae superioris. 
Rectus superior. 
Rectus inferior. 
Rectus internus. 
Rectus externus. 
Obliquus superior. 
Dissection.-To open the cavity of the orbit, remove the skull-cap and brain; then saw 
through the frontal bone at the inner extremity of the supraorbital ridge and externally at its 
junction with the malar. Break in pieces the thin roof of the orbit by a few slight blows of 
the hammer, and take it away; drive forward the superciliary portion of the frontal bone by a 
smart stroke, but do not remove it, as that would destroy the pulley of the Obliquus superior. 
When the fragments are cleared away, the periosteum of the orbit will be exposed; this being 
removed, together with the fat which fills the cavity of the orbit, the several muscles of this 
region can be examined. The dissection will be facilitated by distending the globe of the eye. 
In order to effect this, puncture the optic nerve near the eyeball with a curved needle, and push 
the needle onward into the globe; insert the point of a blowpipe through this aperture and force 
a little air into the cavity of the eyeball ■ then apply a ligature round the nerve so as to pre- 
vent the air escaping. The globe being now drawn forward, the muscles will be put upon the 
stretch. [Heusman's method of inflating the ball through a valvular opening in the cornea is 
much preferable. If the air escapes, the ball can be reinflated.] 
The Levator palpebrse superioris is thin, flat, and triangular in shape. It 
arises from the under surface of the lesser wing of the sphenoid, immediately in 
front of the optic foramen, and is inserted by a broad aponeurosis into the anterior 
surface of the superior tarsal cartilage. At its origin it is narrow and tendinous, 
but soon becomes broad and fleshy, and finally terminates in a broad aponeurosis. 
Relations.-By its upper surface with the frontal nerve and artery, the perios- 
teum of the orbit, and in front with the inner surface of the broad tarsal ligament; 
by its under surface with the Superior rectus, and in the lid with the conjunctiva. 
A small branch of the third nerve enters its under surface. 
The Superior rectus, the thinnest and narrowest of the four Recti, arises from 
Obliquus inferior. 372 
MUSCLFS AND FASCIAE. 
the upper margin of the optic foramen beneath the Levator palpebrse and Superior 
oblique, and from the fibrous sheath of the optic nerve, and is inserted, by a tendin- 
Fig. 285. 
Muscles of the Right Orbit. 
ous expansion, into the sclerotic coat about three or four lines from the margin of 
the cornea. 
Relations.-By its upper surface with the Levator palpebrae; by its under 
surface with the optic nerve, the ophthalmic artery, the nasal nerve, and the branch 
of the third nerve which supplies it; and in front with the tendon of the Superior 
oblique and the globe of the eye. 
The Inferior and Internal Recti arise by a common tendon (the ligament of 
Zinn),1 which is attached round the circumference of the optic foramen, except at 
its upper and outer part. The External rectus 
has two heads: the upper one arises from the 
outer margin of the optic foramen immediately 
beneath the Superior rectus; the lower head, 
partly from the ligament of Zinn and partly 
from a small pointed process of bone on the 
lower margin of the sphenoidal fissure. Each 
muscle passes forward in the position implied by 
its name, to be inserted by a tendinous expan- 
sion (the tunica albuginea) into the sclerotic 
coat, about three or four lines from the margin 
of the cornea. Between the two heads of the 
External rectus is a narrow' interval, through 
which pass the third, the nasal branch of the 
fifth and the sixth nerves, and the ophthalmic 
vein. Although nearly all of these muscles present a common origin and are 
inserted in a similar manner into the sclerotic coat, there are certain differences to 
be observed in them as regards their length and breadth. The Internal rectus is 
the broadest; the External, the longest; and the Superior, the thinnest and nar- 
rowest. 
The Superior oblique is a fusiform muscle placed at the upper and inner side 
Fig. 286. 
Superior 
le/vatov 
IJaLpcbTceS'u'V£TLorr 
Olliyuus Superior 
Rectus - 
Intwjias 
Bcctus Inferior 
Its Upper 11 e ted 
Reiver ILcccI 
The Relative Position and Attachment of 
the Muscles of the Left Eyeball. 
1 The ligament of Zinn ought, perhaps more appropriately, to be termed the aponeurosis or tendon 
of Zinn. Mr. C. B. Lockwood has described a somewhat similar structure on the under surface of 
the superior rectus muscle which is attached to the lesser wing of the sphenoid, forming the upper 
and outer margin of the optic foramen. This superior tendon gives origin to the superior rectus, the 
superior head of the external rectus, and the upper part of the internal rectus (JbwmaZ of Anatomy 
and Physiology, vol. xx. Part I. p. 1). ORBITAL REGION. 
373 
of the orbit internal to the Levator palpebrse. It arises about a line above the inner 
margin of the optic foramen, and, passing forward to the inner angle of the orbit, 
terminates in a rounded tendon, which plays in a ring or pulley formed by fibro-car- 
tilaginous tissue attached to a depression beneath the internal angular process of the 
frontal bone, the contiguous surfaces of the tendon and ring being lined by a deli- 
cate synovial membrane and enclosed in a thin fibrous investment. The tendon is 
reflected backward, outward, and downward beneath the Superior rectus to the outer 
part of the globe of the eye, and is inserted into the sclerotic coat midway between 
the cornea and entrance of the optic nerve, the insertion of the muscle lying between 
the Superior and External recti. 
Relations.-By its upper surface with the periosteum covering the roof of the 
orbit and the fourth nerve: the tendon, where it lies on the globe of the eye, is 
covered by the Superior rectus; by its under surface with the nasal nerve and the 
upper border of the Internal rectus. 
The Inferior oblique is a thin, narrow muscle placed near the anterior margin 
of the orbit. It arises from a depression in the orbital plate of the superior maxil- 
lary bone external to the orifice of the nasal duct. Passing outward, backward, 
and upward beneath the Inferior rectus, and between the eyeball and the External 
rectus, it is inserted into the outer part of the sclerotic coat between the Superior 
and External recti, near the tendon of insertion of the Superior oblique. 
Relations.-By its ocular surface with the globe of the eye and with the Infe- 
rior rectus ; by its orbital surface with the periosteum covering the floor of the orbit 
and with the External rectus. Its borders look forward and backward; the poste- 
rior one receives a branch of the third nerve. 
Nerves.-The Levator palpebrae, Inferior oblique, and all the Recti excepting 
the External are supplied by the third nerve; the Superior oblique, by the fourth; 
the External rectus, by the sixth. 
Actions.-The Levator palpebrae raises the upper eyelid, and is the direct antag- 
onist of the Orbicularis palpebrarum. The four Recti muscles are attached in such a 
manner to the globe of the eye that, acting singly, they will turn it either upward, 
downward, inward, or outward, as expressed by their names. The movement pro- 
duced by the Superior and Inferior rectus is not quite a simple one, for, inasmuch 
as they pass obliquely outward and forward to the eyeball, the elevation or depres- 
sion of the cornea must be accompanied by a certain deviation inward, with a slight 
amount of rotation, which, however, is corrected by the Oblique muscles, the Infe- 
rior oblique correcting the deviation inward of the Superior rectus, and the Supe- 
rior oblique that of the Inferior rectus. The contraction of the External and Inter- 
nal recti, on the other hand, produces a precisely horizontal movement. If any two 
Recti [of one eye] act together, they carry the globe of the eye in the diagonal of 
these directions-viz. upward and inward, upward and outward, downward and 
inward, or downward and outward. The movement of circumduction, as in looking 
round a room, is performed by the alternate action of the four Recti. The Oblique 
muscles rotate the eyeball on its antero-posterior axis, this kind of movement being 
required for the correct viewing of an object when the head is moved laterally, as 
from shoulder to shoulder, in order that the picture may fall in all respects on the 
same part of the retina of each eye.1 [It should be noted that sometimes the corre- 
sponding Recti muscles and sometimes the opposite ones of the two eyes act together; 
for instance, the two Superior and Inferior recti carry both eyeballs upward and 
downward respectively. In looking toward the right the right External and left 
Internal recti act together, the reverse being the case in looking toward the left. 
In turning both eyes toward the middle line, as in directing our vision toward an 
object less than twenty feet distant, the two Internal recti act together.] 
Surgical Anatomy.-The position and exact point of insertion of the tendons of the 
■ ''On the Oblique Muscles of the Eye in Man and Vertebrate Animals," by John Struthers, 
M. D., in Anatomical and Physiological Observations. (For a more full account of the various co-ordi- 
nated actions of the muscles of a single eye and of both eyes than our space allows, the reader may 
be referred to Dr. M. Foster's Textbook of Physiology 4th ed., pp. 542-547.)' 374 
MUSCLES AND FASCIAE. 
Internal and External recti muscles into the globe should be carefully examined from the front 
of the eyeball, as the surgeon is often required to divide one or the other muscle for the cure of 
strabismus. In convergent strabismus, which is the more common form of the disease, the eye 
is turned inward, requiring the division of the Internal rectus. In the divergent form, which is 
more rare, the eye is turned outward, the External rectus being especially implicated. The 
deformity produced in either case is to be remedied by division of one or the other muscle. The 
operation is thus effected : The lids are to be well separated ; the eyeball being drawn outward, 
the conjunctiva should be raised by a pair of forceps and divided immediately beneath the lower 
border of the tendon of the Internal rectus, a little behind its insertion into the sclerotic; the 
capsule of Tenon is then divided, and into the small aperture thus made a blunt hook is passed 
upward between the muscle and the globe, and the tendon of the muscle and conjunctiva cover- 
ing it divided by a pair of blunt-pointed scissors. Or the tendon may be divided by a subcon- 
junctival incision, one blade of the scissors being passed upward between the tendon and the 
conjunctiva, and the other between the tendon and the sclerotic. The student when dissecting 
these muscles should remove on one side of the subject the conjunctiva from the front of the eye, 
in order to see more accurately the position of the tendons, while on the opposite side the opera- 
tion may be performed. 
5. Nasal Region (Figs. 282, 284). 
Pyramidalis nasi. 
Levator labii superioris aleeque nasi. 
Dilatator naris posterior. 
Dilatator naris anterior. 
Compressor nasi. 
Compressor narium minor. 
The Pyramidalis nasi is a small pyramidal slip prolonged downward from the 
Occipito-frontalis upon the side of the nose, where it becomes tendinous and blends 
with the Compressor nasi. As the two muscles descend they diverge, leaving an 
angular interval between them. 
Relations.-By its upper surface with the skin; by its under surface with the 
frontal and nasal bones. 
The Levator labii superioris alseque nasi is a thin triangular muscle placed 
by the side of the nose and extending between the inner margin of the orbit and 
upper lip. It arises by a pointed extremity from the upper part of the nasal pro- 
cess of the superior maxillary bone, and, passing obliquely downward and outward, 
divides into two slips, one of which is inserted into the cartilage of the ala of the 
nose; the other is prolonged into the upper lip, becoming blended with the Orbicu- 
laris and Levator labii superioris proprius. 
Relations.-In front with the integument, and with a small part of the Orbic- 
ularis palpebrarum above. 
The Dilatator naris posterior is a small muscle which is placed partly beneath 
the proper elevator of the nose and lip. It arises from the margin of the nasal 
notch of the superior maxilla and from the sesamoid cartilages, and is inserted into 
the skin near the margin of the nostril. 
The Dilatator naris anterior is a thin delicate fasciculus passing from the 
cartilage of the ala of the nose to the integument near its margin. This muscle is 
situated in front of the preceding. 
The Compressor nasi is a small, thin, triangular muscle arising by its apex 
from the superior maxillary bone, above and a little external to the incisive fossa; 
its fibres proceed upward and inward, expanding into a thin aponeurosis which is 
attached to the fibro-cartilage of the nose, and is continuous on the bridge of the 
nose with that of the muscle of the opposite side and with the aponeurosis of the 
Pyramidalis nasi. 
The Compressor narium minor is a small muscle attached by one end to the 
alar cartilage, and by the other to the integument at the end of the nose. 
The Depressor alee nasi is a short, radiated muscle arising from the incisive 
fossa of the superior maxilla; its fibres ascend to be inserted into the septum and 
back part of the ala of the nose. This muscle lies between the mucous membrane 
and muscular structure of the lip. 
Nerves.-All the muscles of this group are supplied by the facial nerve. 
Actions.-The Pyramidalis nasi draws down the inner angle of the eyebrows 
and produces transverse wrinkles over the bridge of the nose; by some anatomists 
Depressor alse nasi. SUPERIOR MAXILLARY REGION. 
375 
it is also considered as an elevator of the ala, and consequently a dilator of the 
nose. [Although this muscle anatomically seems to be a continuation of the Occip- 
ito frontalis downward, it is really the reverse. Its origin is from the nose below, 
and its insertion into the Occipito-frontal and skin. If one pole of a battery be 
placed in front of the lobe of the ear, and the other (a small pointed one) be carried 
up and down over the nose and forehead in the middle line, it is easy to find a 
nodal point of indifference, above which the Occipito-frontal draws the parts upward, 
and below which the Pyramidalis draws them downward.] The Levator labii superi- 
oris alrnque nasi draws upward the upper lip and ala of the nose; its most important 
action is upon the nose, which it dilates to a considerable extent. The action of 
this muscle produces a marked influence over the countenance, and it is the prin- 
cipal agent in the expression of indignation [and disgust]. The two Dilatatores 
nasi enlarge the aperture of the nose. Their action in ordinary breathing is to 
resist the tendency of the nostrils to close from atmospheric pressure, but in diffi- 
cult breathing they may be noticed to be in violent action, as well as in some emo- 
tions, as anger. The Depressor alee nasi is a direct antagonist of the preceding 
muscles, drawing the ala of the nose downward, and thereby constricting the aper- 
ture of the nares. The Compressor nasi depresses the cartilaginous part of the nose 
and compresses the alee together. 
Levator labii superioris. 
Levator anguli oris. 
6. Superior Maxillary Region (Fig. 282). 
Zygomaticus major. 
Zygomaticus minor. 
The Levator labii superioris (proprius) is a thin muscle of a quadrilateral 
form. It arises from the lower margin of the orbit immediately above the infra- 
orbital foramen, some of its fibres being attached to the superior maxilla, others to 
the malar bone: its fibres converge to be inserted into the muscular substance of 
the upper lip. 
Relations.-By its superficial surface with the lower segment of the Orbicu- 
laris palpebrarum; below, it is subcutaneous. By its deep surface it conceals the 
origin of the Compressor nasi and Levator anguli oris muscles, and the infraorbital 
vessels and nerve as they escape from the infraorbital foramen. 
The Levator anguli oris arises from the canine fossa immediately below the 
infraorbital foramen ; its fibres incline downward and a little outward, to be inserted 
into the angle of the mouth, intermingling with those of the Zygomaticus major, the 
Depressor anguli oris, and the Orbicularis. 
Relations.-By its superficial surface with the Levator labii superioris and the 
infraorbital vessels and nerves; by its deep surface with the superior maxilla, the 
Buccinator, and the mucous membrane. 
The Zygomaticus major is a slender fasciculus which arises from the malar 
bone in front of the zygomatic suture, and, descending obliquely downward and 
inward, is inserted into the angle of the mouth, where it blends with the fibres of 
the Levator anguli oris, the Orbicularis, and the Depressor anguli oris. 
Relations.-By its superficial surface with the subcutaneous adipose tissue; 
by its deep surface with the malar bone and the Masseter and Buccinator 
muscles. 
The Zygomaticus minor arises from the malar bone immediately behind the 
maxillary suture, and, passing downward and inward, is continuous with the Orbic- 
ularis oris at the outer margin of the Levator labii superioris: it lies in front of the 
preceding. 
Relations.-By its superficial surface with the integument and the Orbicularis 
palpebrarum above; by its deep surface with the Levator anguli oris. 
Nerves.-This group of muscles is supplied by the facial nerve. 
Actions.-The Levator labii superioris is the proper elevator of the upper lip, 
carrying it at the same time a little forward. It assists in forming the naso-labial 
ridge, which passes from the side of the nose to the upper lip and gives to the face MUSCLES AND FASCIAE. 
376 
an expression of sadness. The Levator anguli oris raises the angle of the mouth 
and assists the preceding muscle in producing the naso-labial ridge. The Zygo- 
maticus major draws the angle of the mouth backward and upward, as in laughing; 
whilst the Zygomaticus minor, being inserted into the outer part of the upper lip, 
and not into the angle of the mouth, draws it backward, upward, and outward, and 
thus gives to the face an expression of sadness. 
7. Inferior Maxillary Region (Fig. 282). 
Levator labii inferioris (Levator menti). 
Depressor labii inferioris (Quadratus menti). 
Depressor anguli oris (Triangularis menti). 
Dissection.-The muscles in this region may be dissected by making a vertical incision 
through the integument from the margin of the lower lip to the chin : a second incision should 
then be carried along the margin of the lower jaw as far as the angle, and the integument care- 
fully removed in the direction shown in Fig. 281. 
The Levator labii inferioris (Levator menti) is to be dissected by everting 
the lower lip and raising the mucous membrane. It is a small conical fasciculus 
placed on the side of the fraenum of the lower lip. It arises from the incisive fossa, 
external to the symphysis of the lower jaw: its fibres descend to be inserted into 
the integument of the chin. 
Relations.-On the inner surface with the mucous membrane; in the median 
line it is blended with the muscle of the opposite side; and on its outer side with 
the Depressor labii inferioris. 
The Depressor labii inferioris (Quadratus menti) is a small quadrilateral mus- 
cle situated at the outer side of the preceding. It arises from the external oblique 
line of the lower jaw, between the symphysis and mental foramen, and passes obliquely 
upward and inward, to be inserted into the integument of the lower lip, its fibres 
blending with the Orbicularis and with those of its fellow of the opposite side. It 
is continuous with the fibres of the Platysma at its origin. This muscle contains 
much yellow fat intermingled with its fibres. 
Relations.-By its superficial surface with part of the Depressor anguli oris 
and with the integument, to which it is closely connected ; by its deep surface with 
the mental vessels and nerves, the mucous membrane of the lower lip, the labial 
glands, and the Levator menti, with which it is intimately united. 
The Depressor anguli oris is triangular in shape, arising by its broad base 
from the external oblique line of the lower jaw, whence its fibres pass upward to 
be inserted by a narrow fasciculus into the angle of the mouth. It is continuous 
with the Platysma at its origin, and with the Orbicularis and Risorius at its inser- 
tion, and some of its fibres are directly continuous with those of the Levator anguli 
oris. 
Relations.-By its superficial surface with the integument; by its deep surface 
with the Depressor labii inferioris and Buccinator. 
Nerves.-The group of muscles is supplied by the facial nerve. 
Actions.-The Levator labii inferioris raises the lower lip and protrudes it for- 
ward, and at the same time wrinkles the integument of the chin, expressing doubt 
or disdain. [A tremulous action of this muscle is excellently shown in children 
just on the verge of tears. In Delaroche's " Marie Antoinette going to Execu- 
tion," one of the female spectators has a very delicate expression of sorrow by the 
slight elevation of the chin by this muscle, while the angles of the mouth are slightly 
drawn down by the Depressor anguli oris.] The Depressor labii inferioris draws 
the lower lip directly downward and a little outward, as in the expression of irony. 
The Depressor anguli oris depresses the angle of the mouth, being the antagonist to 
the Levator anguli oris and Zygomaticus major; acting with these muscles, it will 
draw the angle of the mouth directly backward. [The Depressor anguli oris is per- 
haps the most peculiar and most expressive single muscle in the human face. In 
fact, the angle of the mouth is the most mobile and important centre of expression INTERMAXILLARY REGION. 
377 
in the face. By no one line can the expression be so easily and so widely changed. 
If two circles be drawn to represent two faces, and two dots and a line in each for 
the eyes and nose, thus reducing the features to their simplest expression, one face 
can be made to smile by inserting a line for the mouth, the angles being turned 
upward; while the other can be made to express great sadness by turning the angles 
of the mouth downward.] 
8. Intermaxillary Region. 
Orbicularis oris. 
Buccinator. 
Risorius. 
Dissection.-The dissection of these muscles may be considerably facilitated by filling the 
cavity of the mouth with tow, so as to distend the cheeks and lips: the mouth should then be 
closed by a few stitches and the integument carefully removed from the surface. 
The Orbicularis oris (Fig. 282) is a sphincter muscle, elliptic in form, composed 
of concentric fibres which surround the orifice of the mouth. It consists of two 
thick semicircular planes of muscular fibre which interlace on either side with those 
of the Buccinator and other muscles inserted into the lips. On the free margin of 
the lips the muscular fibres (marginal or labial fibres) are continued uninterruptedly 
from one lip to the other around the corner of the mouth, forming a roundish fascic- 
ulus of fine pale fibres closely approximated. Outside these are other fibres (facial), 
which are thinner than the others and are continuous at the angle of the mouth with 
the Buccinator; some of the fibres, the central ones, decussating in this situation, 
and others, the outer ones, being directly continuous with the fibres of the Buccina- 
tor. The various muscles which converge to the lips blend with the facial portion, 
the fibres of the muscles becoming directly continuous. To the outer part of the 
muscle some accessory fibres are added by which the lips are connected directly with 
the maxillary bones and septum of the nose. The additional fibres for the upper- 
segment consist of four bands, two of which (Accessorii orbicularis superioris) arise 
from the alveolar border of the superior maxilla opposite the incisor teeth, and, 
arching outward on each side, are continuous at the angles of the mouth with the 
other muscles inserted into this part. The two remaining muscular slips, called the 
Naso-labialis, connect the upper lip to the septum of the nose; as they descend 
from the septum an interval is left between them. It is this interval which forms 
the depression seen on the surface of the skin beneath the septum of the nose 
[called the philtrum]. The additional fibres of the lower segment (Meeessom orbic- 
ularis inferioris) arise from the inferior maxilla externally to the Levator labii 
inferioris, and arch outward to the angles of the mouth to join the Buccinator and 
the other muscles attached to this part. 
Relations.-By its superficial surface with the integument, to which it is closely 
connected ; by its deep surface with the buccal mucous membrane, the labial glands, 
and coronary vessels. By its outer circumference it is blended with the numerous 
muscles which converge to the mouth from various parts of the face. Its inner cir- 
cumference is free and covered by the mucous membrane. 
The Buccinator (Fig. 295) is a broad, thin muscle, quadrilateral in form, which 
occupies the interval between the jaws at the side of the face. It arises from the 
outer surface of the alveolar processes of the upper and lower jaws, corresponding 
to the three molar teeth, and behind from the anterior border of the pterygo-maxil- 
lary ligament. The fibres converge toward the angle of the mouth, where the cen- 
tral fibres intersect each other, those from below being continuous with the upper 
segment of the Orbicularis oris, and those from above with the inferior segment : 
the highest and lowest fibres continue forward uninterruptedly into the correspond- 
ing segment of the lip, without decussation. 
Relations.-By its superficial surface behind with a large mass of fat, which 
separates it from the ramus of the lower jaw, the Masseter, and a small portion of 
the Temporal muscle ; anteriorly, with the Zygomatici, Risorius, Levator anguli oris, 
Depressor anguli oris, and Stenson's duct, which pierces it opposite the second molar 378 
MUSCLES AND FASCIAE. 
tooth of the upper jaw; the facial artery and vein cross it from below upward; it 
is also crossed by the branches of the facial and buccal nerves; by its internal sur- 
face with the buccal glands and mucous membrane of the mouth. 
The Pterygo-maxillary ligament separates the Buccinator muscle from the Supe- 
rior constrictor of the pharynx. It is a tendinous band, attached by one extremity 
to the apex of the internal pterygoid plate, and by the other to the posterior extrem- 
ity of the internal oblique line of the lower jaw. Its inner surface corresponds to 
the cavity of the mouth and is lined by mucous membrane. Its outer surface is 
separated from the ramus of the jaw by a quantity of adipose tissue. Its posterior 
border gives attachment to the Superior constrictor of the pharynx ; its anterior 
border, to the fibres of the Buccinator. (See Fig. 295.) 
The Risorius (Santorini) (Fig. 282) consists of a narrow bundle of fibres which 
arises in the fascia over the Masseter muscle, and, passing horizontally forward, is 
inserted into the angle of the mouth, joining with the fibres of the Depressor anguli 
oris. It is placed superficial to the Platysma, and is broadest at its outer extremity. 
This muscle varies much in its size and form. 
Nerves.-The Orbicularis oris and the Risorius are supplied by the facial, the 
Buccinator by the facial and by the buccal branch of the inferior maxillary nerve; 
which latter, however, is by many anatomists regarded as a sensory nerve only. 
Actions.-The Orbicularis oris is the direct antagonist of all those muscles which 
converge to the lips from the various parts of the face, its ordinary action producing 
the direct closure of the lips, and its forcible action throwing the integument into 
wrinkles, on account of the firm connection between the latter and the surface of 
the muscle. [These wrinkles radiate from the mouth, and can be best seen in the 
faces of some old women.] The Buccinators contract and compress the cheeks, so 
that during the process of mastication the food is kept under the immediate pressure 
of the teeth. When the cheeks have been previously distended with air, the Buc- 
cinator muscles expel it from between the lips, as in blowing a trumpet. Hence the 
name (buccina, a trumpet). The Risorius retracts the angles of the mouth, and is 
therefore regarded as the "smiling" muscle. 
9. Temporo-maxillary Region. 
Masseteric Fascia.-Covering the masseter muscle and firmly connected with it 
is a strong layer of fascia derived from the deep cervical fascia of the neck. Above, 
this fascia is attached to the lower border of the zygoma, and behind it covers the 
parotid gland, constituting the parotid fascia. 
The Masseter is exposed by the removal of this fascia (Fig. 282); it is a short, 
thick muscle, somewhat quadrilateral in form, consisting of two portions, superficial 
and deep. The superficial portion, the larger, arises by a thick tendinous aponeur- 
osis from the malar process of the superior maxilla, and from the anterior two-thirds 
of the lower border of the zygomatic arch : its fibres pass downward and backward, 
to be inserted into the angle and lower half of the outer surface of the ramus of the 
jaw. The deep portion is much smaller and more muscular in texture; it arises 
from the posterior third of the lower border and the whole of the inner surface of 
the zygomatic arch ; its fibres pass downward and forward, to be inserted into the 
upper half of the ramus and outer surface of the coronoid process of the jaw. The 
deep portion of the muscle is partly concealed in front by the superficial portion; 
behind, it is covered by the parotid gland. The fibres of the two portions are 
united at their insertion. 
Relations.-By its superficial surface with the integument; above, with the 
Orbicularis palpebrarum and Zygomatici, and with Stenson's duct, the branches of 
the facial nerve, and the transverse facial vessels, which cross it; by its deep surface 
with the ramus of the jaw and the Buccinator, from which it is separated by a mass 
of fat. Its posterior margin is overlapped by the parotid gland. Its anterior mar- 
gin projects over the Buccinator muscle, and the facial vein lies on it below. 
Masseter. 
Temporal. TEMP OR O-MAXILLAR Y REGION. 
379 
The Temporal Fascia is seen at this stage of the dissection covering in the Tem- 
poral muscle. It is a strong fibrous investment, affording attachment by its inner 
surface to the superficial fibres of the muscle. Above, it is a single layer attached 
to the entire extent of the temporal ridge, but below, where it is attached to the 
zygoma, it consists of two layers, one of which is inserted into the outer, and the 
other into the inner border of the zygomatic arch. A small quantity of fat, the 
orbital branch of the temporal artery, and a filament from the orbital branch of the 
superior maxillary nerve are contained between these two layers. It is covered on 
its outer surface by the aponeurosis of the Occipito-frontalis, the Orbicularis palpe- 
brarum, the Attollens and Attrahens aurem muscles; the temporal vessels and nerves 
cross it from below upward. 
Dissection.-In order to expose the temporal muscle remove the temporal fascia, which may 
be effected by separating it at its attachment along the upper border of the zygoma and dissect- 
ing it upward from the surface of the muscle. The zygomatic arch should then be divided, in 
front, at its junction with the malar bone, and behind near the external auditory meatus, and 
drawn downward with the Masseter, which should be detached from its insertion into the ramus 
and angle of the jaw. The whole extent of the temporal muscle is then exposed. 
The Temporal (Fig. 287) is a broad radiating muscle situated at the side of the 
head and occupying the entire extent of the temporal fossa. It arises from the 
whole of the temporal fossa, except that portion formed by the malar bone. Its 
Fig. 287. 
The Temporal Muscle, the Zygoma and the Masseter muscle having been removed. 
attachment extends from the external angular process of the frontal in front to the 
mastoid portion of the temporal behind, and from the curved line on the frontal 
and parietal bones above to the pterygoid ridge on the great wing of the sphenoid 
below. It is also attached to the inner surface of the temporal fascia. Its fibres 
converge as they descend, and terminate in an aponeurosis, the fibres of which, 
radiated at its commencement, converge into a thick and flat tendon which is 
inserted into the inner surface, apex, and anterior border of the coronoid process of 
the jaw, nearly as far forward as the last molar tooth. 
Relations.-By its superficial surface with the integument, the temporal fascia, 
the aponeurosis of the Occipito-frontalis, the Attollens and Attrahens aurem mus- 
cles, the temporal vessels and nerves, the zygoma and Masseter; by its deep surface 
with the temporal fossa, the External pterygoid and part of the Buccinator muscles, 380 
MUSCLES AND FASCIAE. 
the internal maxillary artery, its deep temporal branches, and the temporal nerves. 
Behind the tendon are the masseteric vessels and nerve, and in front of it the buccal 
vessels and nerve. 
Nerves.-Both muscles are supplied by the inferior maxillary nerve. 
10. Pterygo-maxillary Region (Fig. 288). 
External Pterygoid. 
Internal Pterygoid. 
Dissection.-The Temporal muscle having been examined, saw through the base of the coro- 
noid process, and draw it upward, together with the Temporal muscle, which should be detached 
from the surface of the temporal fossa. Divide the ramus of the jaw just below the condyle, and 
also, by a transverse incision extending across the middle, just above the dental foramen; 
remove the fragment, and the Pterygoid muscles will be exposed. 
The External pterygoid is a short thick muscle, somewhat conical in form, 
which extends almost horizontally between the zygomatic fossa and the condyle of 
the jaw. It arises from the pterygoid ridge on the great wing of the sphenoid and 
the portion of bone included between it and the base of the pterygoid process, and 
from the outer surface of the external pterygoid plate. Its fibres pass horizontally 
backward and outward, to be inserted into a depression in front of the neck of the 
condyle of the lower jaw, and into the corresponding part of the interarticular fibro; 
cartilage. This muscle at its origin appears to consist of two portions separated by 
a slight interval, hence the terms upper and lower head sometimes used in the descrip- 
tion of the muscle. 
Relations.-By its external surface with the ramus of the lower jaw, the inter- 
nal maxillary artery, which crosses it,1 the tendon of the Temporal muscle, and the 
Fig. 288. 
The Pterygoid Muscles, the Zygomatic Arch and a portion of the Ramus of the Jaw having been removed. 
Masseter; by its internal surface it rests against the upper part of the Internal 
pterygoid, the internal lateral ligament, the middle meningeal artery, and inferior 
maxillary nerve; by its upper border it is in relation with the temporal and 
masseteric branches of the inferior maxillary nerve; by its lower border it is in 
relation with the inferior dental and gustatory nerves, and it is pierced by the buccal 
nerve. 
1 This is the usual relation, but in many cases the artery will be found below the muscle. OF THE NECK. 
381 
The Internal pterygoid is a thick quadrilateral muscle, and resembles the 
Masseter in form, structure, and the direction of its fibres. It arises from the 
pterygoid fossa, being attached to the inner surface of the external pterygoid plate 
and to the grooved surface of the tuberosity of the palate bone, and by a second 
slip from the outer surface of the tuberosity of the palate bone, and from the 
tuberosity of the superior maxillary bone; its fibres pass downward, outward, and 
backward, to be inserted by strong tendinous lamime into the lower and back part 
of the inner side of the ramus and angle of the lower jaw as high as the dental 
foramen. 
Relations.-By its external surface with the ramus of the lower jaw, from 
which it is separated, at its upper part, by the External pterygoid, the internal 
lateral ligament, the internal maxillary artery, and the dental vessels and nerves; 
by its internal surface with the Tensor palati, being separated from the Superior 
constrictor of the pharynx by a cellular interval. 
Nerves.-These muscles are supplied by the inferior maxillary nerve. 
Actions.-The Temporal and Masseter and Internal pterygoid raise the lower 
jaw against the upper with great force. The superficial portion of the Masseter 
and the Internal pterygoid assist the External pterygoid in drawing the lower jaw 
forward upon the upper, the jaw being drawn back again by the deep fibres of the 
Masseter and posterior fibres of the Temporal. The External Pterygoid muscles 
are the direct agents in the trituration of the food, drawing the lower jawT directly 
forward, so as to make the lower teeth project beyond the upper. If the muscle of 
one side acts, the corresponding side of the jaw is drawn forward, and, the other 
condyle remaining fixed, the symphysis deviates to the opposite side. The alterna- 
tion of these movements on the two sides produces trituration. [The finger placed 
on the Temporal and Masseter while they are alternately contracted and relaxed 
appreciates very distinctly their limits.] 
MUSCLES AND FASCDE OF THE NECK. 
The Muscles of the Neck may be arranged into groups corresponding with the 
region in which they are situated. These groups are nine in number: 
1. Superficial Region. 
2. Depressors of the Os Hyoides and 
Larynx. 
3. Elevators of the Os Hyoides and 
Larynx. 
4. Muscles of the Tongue. 
5. Muscles of the Pharynx. 
6. Muscles of the Soft Palate. 
7. Muscles of the Anterior Vertebral 
Region. 
8. Muscles of the Lateral Vertebral 
Region. 
9. Muscles of the Larynx. 
The muscles contained in each of these groups are the following: 
1. Superficial Region. 
Platysma myoides. 
Sterno-cleido-mastoid. 
2. Infrahyoid Region. 
Depressors of the Os Hyoides and 
Larynx. 
Sterno-hyoid. 
Sterno-thyroid. 
Thyro-hyoid. 
Omo-hyoid. 
3. Suprahyoid Region. 
Elevators of the Os Hyoides and 
Larynx. 
Digastric. 
Stylo-hyoid. 
Mylo-hyoid. 
Genio-hyoid. 
4. Lingual Region. 
Muscles of the Tongue. 
Genio-hyo-glossus. 
Hyo-glossus. MUSCLES AND FAS CI MJ. 
382 
Lingualis. 
Stylo-glossus. 
Palato-glossus. 
5. Muscles of the Pharynx. 
Constrictor inferior. 
Constrictor medius. 
Constrictor superior. 
Stylo-pharyngeus. 
Palato-pharyngeus. 
6. Muscles of the Soft Palate. 
Levator palati. 
Tensor palati. 
Azygos uvulae. 
Palato-glossus. 
Palato-pharyngeus. 
7. Muscles of the Anterior Vertebral 
Region. 
Rectus capitis anticus major. 
Rectus capitis anticus minor. 
Rectus lateralis. 
Longus colli. 
8. Muscles of the Lateral Vertebral 
Region. 
Scalenus anticus. 
Scalenus medius. 
Scalenus posticus. 
9. Muscles of the Larynx. 
Included in the description of the 
Larynx. 
1. Superficial Cervical Region. 
Platysma myoides. 
Sterno-cleido-mastoid. 
Dissection.-A block having been placed at the back of the neck, and the face turned to the 
side opposite that to be dissected, so as to place the parts upon the stretch, make two transverse 
incisions-one from the chin, along the margin of the lower jaw, to the mastoid process; and 
the other along the upper border of the clavicle. Connect these by an oblique incision made in 
the course of the Sterno-mastoid muscle from the mastoid process to the sternum ; the two flaps 
of integument having been removed in the direction shown in Fig. 281, the superficial fascia will 
be exposed. 
The Superficial Cervical Fascia is exposed on the removal of the integument 
from the side of the neck ; it is an extremely thin aponeurotic lamina which is 
hardly demonstrable as a separate membrane. Beneath it are found the Platysma 
myoides muscle, the external jugular vein, and some superficial branches of the 
cervical plexus of nerves. 
The Platysma myoides (Fig. 282, p. 368) is a broad, thin plane of muscular fibres 
placed immediately beneath the skin on each side of the neck. It arises by thin 
fibrous bands from the clavicle and acromion and from the fascia covering the upper 
part of the Pectoral, Deltoid, and Trapezius muscles: its fibres proceed obliquely 
upward and inward along the side of the neck, to be inserted into the lower jaw 
beneath the external oblique line, some passing forward to the angle of the mouth, 
and others becoming lost in the cellular tissue of the face. The most anterior fibres 
interlace in front of the jaw with the fibres of the muscle of the opposite side ; those 
next in order become blended with the Depressor labii inferioris and the Depressor 
anguli oris; others are prolonged upon the side of the cheek, and interlace, near the 
angle of the mouth, with the muscles in this situation, and may occasionally be 
traced to the Zygomatic muscles or to the margin of the Orbicularis palpebrarum. 
Beneath the Platysma the external jugular vein may be seen descending from the 
angle of the jaw to the clavicle. It is essential to remember the direction of the 
fibres of the Platysma in connection with the operation of bleeding from this vessel; 
for if the point of the lancet is introduced in the direction of the muscular fibres, the 
orifice made will be filled up by the contraction of the muscle, and blood will not 
flow; but if the incision is made across the course of the fibres, they will retract 
and expose the orifice in the vein, and so facilitate the flow of blood. 
Relations.-By its external surface with the integument, to which it is united 
closely below, but more loosely above; by its internal surface with the Pectoralis 
major, Deltoid, and Trapezius, and with the clavicle; in the neck with the external 
and anterior jugular veins, the deep cervical fascia, the superficial branches of the SUPERFICIAL CERVICAL REGION. 
383 
cervical plexus, the Sterno-mastoid, Sterno-hyoid, Omo-hyoid, and Digastric mus- 
cles. In front of the Sterno-mastoid it covers the sheath of the carotid vessels, and 
behind it the Scaleni muscles and the nerves of the brachial plexus. On the face 
it is in relation with the parotid gland, the facial artery and vein, and the Masseter 
and Buccinator muscles. 
The Deep Cervical Fascia (Fig. 289) is exposed on the removal of the Pla- 
tysma myoides. It is a strong fibrous layer which invests the muscles of the neck 
nd encloses the vessels and nerves. It commences as an extremely thin layer at 
Fig. 289. 
Oen o-Ti/yoi-d- 
EVoi/roiE iody 
■AnEfuyti-Zctr vein. 
Comwon carotid artery 
. Stemo-TiyoicL 
End prey u7.or vein 
-aS*temo-diyrotd 
Eterno-zn cestoid 
-Tractiea, 
Ei ewnoya 
trie. nerve] 
(Esophayiis 
East. 717 yular 
vein. 
Sccdemis 
ecnticTZS , 
cerutccd 
"l/eriebral' vessels 
tSceclemis) 
Tnedins] 
Splenins] 
eottt' i 
Lev. any. scap. 
Eemi-syinu.lis colli,. 
Trapezius- 
~ Cbmpleocus 
-Snlezvias capitis 
Section of the Neck at about the level of the Sixth Cervical Vertebra, showing the arrangement of the 
Deep Cervical Fascia. 
the back part of the neck, where it is attached to the spinous process of the seventh 
cervical vertebra and to the ligamentuni nuchae, and, passing forward, invests the 
Trapezius muscle; from the anterior border of this muscle it forms a layer which 
covers in the posterior triangle of the neck, and, passing forward to the posterior 
border of the Sterno-mastoid muscle, divides into two layers, one of which passes in 
front and the other behind that muscle. These join again at the anterior border of 
the Sterno-mastoid, and, being continued forward to the front of the neck, blend 
with the fascia of the opposite side covering the anterior triangle. If traced 384 
MUSCLES AND FASCIAE. 
upward, it is found to pass across the parotid gland and Masseter muscle, form- 
ing the parotid and masseteric fascia, and is attached to the lower border of the 
zygoma, and more anteriorly to the lower border of the body of the jaw; if traced 
downward, it is seen to pass to the upper border of the clavicle and sternum, being 
pierced just above the former bone by the external jugular vein. In the middle 
line of the neck the fascia is thin above and connected to the hyoid bone; but it 
becomes thicker below, and divides, just below the thyroid gland, into two layers, 
the more superficial of which is attached to the upper border of the sternum and 
interclavicular ligament; the deeper and stronger layer is connected to the poste- 
rior border of that bone, covering in the Sterno-hyoid and Sterno-thyroid muscles. 
Between these two layers is a little areolar tissue and fat, and occasionally a small 
lymphatic gland. The deep layer of the cervical fascia (that which lies behind the 
posterior surface of the Sterno-mastoid) sends numerous prolongations, which invest 
the muscles and vessels of the neck ; if traced upward, a process of the fascia of 
extreme density is found passing behind and to the inner side of the parotid gland, 
to be attached to the apex of the styloid process and angle of the lower jaw, termed 
the stylo-maxillary ligament; if traced downward and outward, the fascia will be 
found to enclose the posterior belly of the Omo-hyoid muscle, binding it down by a 
distinct process which descends to be inserted into the sternum and cartilage of the 
first rib, and becomes connected with the costo-coracoid membrane. The deep layer 
of the cervical fascia also assists in forming the sheath which encloses the common 
carotid artery, internal jugular vein, and pneumogastric nerve. There are fibrous 
Fig. 290. 
septa intervening between each of these parts, which, however, are included together 
in one common investment. More internally, a thin layer is continued across the 
trachea and thyroid gland, beneath the Sterno-thyroid muscles, and at the root of 
the neck this may be traced, over the large vessels, to be continuous with the fibrous 
Muscles of the Neck and Boundaries of the Triangles. SUPERFICIAL CERVICAL REGION, 
385 
layer of the pericardium. Lastly a layer of fascia, the prevertebral fascia, is derived 
from the under surface of the cervical fascia; this passes beneath the carotid vessels, 
forming the back of the sheath, and is then prolonged inward, behind the pharynx 
and oesophagus, forming a sheath for the Prevertebral muscles, and downward and 
outward over the Scaleni muscles, the brachial plexus, and subclavian vessels, to 
assist in forming the axillary sheath. 
The Sterno-mastoid, or Sterno-cleido-mastoid (Fig. 290), is a large thick 
muscle, which passes obliquely across the side of the neck, being enclosed between 
the two layers of the deep cervical fascia. It is thick and narrow at its central part, 
but is broader and thinner at each extremity. It arises by two heads from the ster- 
num and clavicle. The sternal portion is a rounded fasciculus, tendinous in front, 
fleshy behind, which arises from the upper and anterior part of the first piece of the 
sternum, and is directed upward, outward, and backward. The clavicular portion 
arises from the inner third of the superior border of the clavicle, being composed of 
fleshy and aponeurotic fibres; it is directed almost vertically upward. These two 
portions are separated from one another at their origin by a triangular cellular inter- 
val, but become gradually blended below the middle of the neck into a thick rounded 
muscle, which is inserted by a strong tendon into the outer surface of the mastoid 
process from its apex to its superior border, and by a thin aponeurosis into the outer 
two-thirds of the superior curved line of the occipital bone. The Sterno-mastoid 
varies much in its extent of attachment to the clavicle: in one case the clavicular 
may be as narrow as the sternal portion; in another, as much as three inches in 
breadth. When the clavicular origin is broad, it is occasionally subdivided into 
numerous slips separated by narrow intervals. More rarely, the corresponding 
margins of the Sterno-mastoid and Trapezius have been found in contact. In the 
application of a ligature to the third part of the subclavian artery it will be neces- 
sary, where the muscles come close together, to divide a portion of one or of both. 
This muscle divides the quadrilateral space at the side of the neck into two tri- 
angles, an anterior and a posterior. The boundaries of the anterior triangle are, in 
front, the median line of the neck ; above, the lower border of the body of the jaw 
and an imaginary line drawn from the angle of the jaw to the mastoid process; 
behind, the anterior border of the Sterno-mastoid muscle. The boundaries of the 
posterior triangle are, in front, the posterior border of the Sterno-mastoid; below, 
the upper border of the clavicle; behind, the anterior margin of the Trapezius.1 
The anterior edge of the muscle forms a very prominent ridge beneath the skin 
which it is important to notice, as it forms a guide to the surgeon in making the 
necessary incisions for ligature of the common carotid artery and for oesophagotomy. 
Relations.-By its superficial surface with the integument and Platysma, from 
which it is separated by the external jugular vein, the superficial branches of the 
cervical plexus, and the anterior layer of the deep cervical fascia. By its deep sur- 
face it rests on the sterno-clavicular articulation, the deep layer of the cervical fascia, 
the Sterno-hyoid, Sterno-thyroid, Omo-hyoid, the posterior belly of the Digastric* 
Levator anguli scapulae, the Splenius, and Scaleni muscles. Below it is in relation 
with the lower part of the common carotid artery, internal jugular vein, pneumo- 
gastric, descendens noni, and communicans noni nerves, and with the deep lym- 
phatic glands-with the spinal accessory nerve, which pierces its upper third, the 
cervical plexus, the occipital artery, and part of the parotid gland. 
Nerves.-The Platysma myoides is supplied by the facial and superficial 
branches of the cervical plexus; the Sterno-cleido-mastoid, by the spinal accessory 
and deep branches of the cervical plexus. 
Actions.-The Platysma myoides produces a slight wrinkling of the surface of 
the skin of the neck in an oblique direction .when the entire muscle is brought into 
action. Its anterior portion, the thickest part of the muscle, depresses the lower 
jaw ; it also serves to draw down the lower lip and angle of the mouth on each side, 
being one of the chief agents in the expression of melancholy. The Sterno-mastoid 
1 The anatomy of these triangles will be more exactly described with that of the vessels of the 
neck. 386 
MUSCLES AND FASCIAE. 
muscles, when both are brought into action, serve to depress the head upon the neck 
and the neck upon the chest. Either muscle, acting singly, flexes the head, and 
(combined with the Splenius and the Obliquus inferior capitis of the opposite side) 
draws it toward the shoulder of the same side, and rotates it so as to carry the face 
toward the opposite side. If the head is fixed they assist in elevating the thorax 
in forced inspiration. [The action of the Platysma can be well shown in the living 
model by its voluntary contraction, either unilateral or bilateral. Its striated oblique 
bundles of fibres, and its action in drawing up the skin of the chest even as far down 
as the nipple, are well seen. The Sterno-mastoid is best brought out by endeavor- 
ing to turn the chin to one side and forcibly resisting this motion by one hand. The 
rounded sternal cord shows especially well.] 
Surgical Anatomy.-The relations of the sternal and clavicular parts of the Sterno- 
mastoid should be carefully examined, as the surgeon is sometimes required to divide one or 
both portions of the muscle in wry-neck. One variety of this "distortion is produced by spas- 
modic contraction or rigidity of the Sterno-mastoid, the head being carried down toward the 
shoulder of the same side, and the face turned to the opposite side and fixed in that position. 
When all other remedies for the relief of this disease have failed subcutaneous division of the 
muscle is resorted to. This is performed by introducing a tenotomy-knife beneath it about half 
an inch above its origin, and dividing it from behind forward whilst the muscle is put well upon 
the stretch. There is seldom any difficulty in dividing the sternal portion. In dividing the 
clavicular portion care must be taken to avoid wounding the external jugular vein, which runs 
parallel with the posterior border of the muscle in this situation, or the anterior jugular vein, 
which crosses beneath it. 
2. Infrahyoid Region (Figs. 290, 291). 
Depressors of the Os Hyoides and Larynx. 
Sterno-hyoid. 
Sterno-thyroid. 
Thyro-hyoid. 
Omo-hyoid. 
Dissection.-The muscles in this region may be exposed by removing the deep fascia from 
the front of the neck. In order to see the entire extent of the Omo-hyoid, it is necessary to divide 
the Sterno-mastoid at its centre and turn its ends aside, and to detach the Trapezius from the 
clavicle and scapula. This, however, should not be done until the Trapezius has been dissected. 
The Sterno-hyoid is a thin, narrow, ribbon-like muscle which arises from the 
inner extremity of the clavicle and the upper and posterior part of the first piece of 
the sternum; passing upward and inward, it is inserted by short tendinous fibres 
into the lower border of the body of the os hyoides. This muscle is separated below 
from its fellow by a considerable interval, but they approach one another in the mid- 
dle of their course, and again diverge as they ascend. It sometimes presents, imme- 
diately above its origin, a transverse tendinous intersection, like those in the Rectus 
abdominis. 
Relations.-By its superficial surface below with the sternum, the sternal end 
of the clavicle, and the Sterno-mastoid, and above with the Platysma and deep cer- 
vical fascia; by its deep surface with the Sterno-thyroid, Crico-thyroid, and Thyro- 
hyoid muscles, the thyroid gland, the superior thyroid vessels, the crico-thyroid and 
thyro-hyoid membranes. 
The Sterno-thyroid is situated beneath the preceding muscle, but is shorter and 
wider than it. It arises from the posterior surface of the first bone of the sternum 
below the origin of the Sterno-hyoid, and generally from the edge of the cartilage 
of the first rib, and is inserted into the oblique line on the side of the ala of the 
thyroid cartilage. This muscle is in close contact with its fellow at the lower part 
of the neck, and is occasionally traversed by a transverse or oblique tendinous inter- 
section, like those in the Rectus abdominis. 
Relations.-By its anterior surface with the Sterno-hyoid, Omo-hyoid, and 
Sterno-mastoid; by its posterior surface, from below upward, with the trachea, 
vena innominata, common carotid (and on the right side the arteria innominata), 
the thyroid gland and its vessels, and the lower part of the larynx. The middle INFRAHYOID REGION. 
387 
thyroid vein lies along its inner border-a relation which it is important to remem- 
ber in the operation of tracheotomy. 
The Thyro-hyoid is a small quadrilateral muscle appearing like a continuation 
of the Sterno-thyroid. It arises from the oblique line on the side of the thyroid 
Fig. 291. 
Muscles of the Neck, anterior view. 
cartilage, and passes vertically upward to be inserted into the lower border of the 
body and greater cornu of the hyoid bone. 
Relations.-By its external surface with the Sterno-hyoid and Omo-hyoid mus- 
cles ; by its internal surface with the thyroid cartilage, the thyro-hyoid membrane, 
and the superior laryngeal vessels and nerve. 
The Omo-hyoid passes across the side of the neck from the scapula to the hyoid 
bone. It consists of two fleshy bellies united by a central tendon. It arises from 
the upper border of the scapula, and occasionally from the transverse ligament 
which crosses the suprascapular notch, its extent of attachment to the scapula vary- 
ing from a few lines to an inch. From this origin the posterior belly forms a flat, 
narrow fasciculus which inclines forward across the lower part of the neck, behind 
the Sterno-mastoid muscle, where it becomes tendinous; it then changes its direc- 
tion, forming an obtuse angle, and the anterior belly ascends almost vertically 
upward close to the outer border of the Sterno-hyoid, to be inserted into the lower 
border of the body of the os hyoides just external to the insertion of the Sterno- 
hyoid. The tendon of this muscle, which varies much in its length and form in 
different subjects, is held in its position by a process of the deep cervical fascia, 
which includes it in a sheath, and is prolonged down to be attached to the cartilage 
of the first rib and the sternum. It is by this means that the angular form of the 
muscle is maintained. 
This muscle subdivides each of the two large triangles at the side of the neck 
into two smaller triangles, the two posterior ones being the posterior superior or 
occipital and the posterior inferior or subclavian; the two anterior, the anterior 
superior oi' superior carotid and the anterior inferior or inferior carotid triangle. 388 
MUSCLES AND FASCIAE. 
Relations.-By its superficial surface with the Trapezius, Subclavius, the 
clavicle, the Sterno-mastoid, deep cervical fascia, Platysma, and integument; by 
its deep surface with the Scaleni, phrenic nerve, lower cervical nerves, sheath of 
the common carotid artery and internal jugular vein, the Sterno-thyroid and 
Thyro-hyoid muscles. 
Nerves.-The Thyro-hyoid is supplied by the hypoglossal, the other muscles 
of this group by branches from the loop of communication between the descendens 
and communicans noni. 
Actions.-These muscles depress the larynx and hyoid bone after they have 
been drawn up with the pharynx in the act of deglutition. The Omo-hyoid mus- 
cles not only depress the hyoid bone, but carry it backward and to one or the other 
side. It is concerned especially in the act of sucking. They are also tensors of 
the cervical fascia. The Thyro-hyoid may act as an elevator of the thyroid carti- 
lage when the hyoid bone ascends, drawing upward the thyroid cartilage behind 
the os hyoides.1 
3. Suprahyoid Region (Figs. 290, 291). 
Elevators of the Os Hyoides-Depressors of the Lower Jaw. 
Digastric. 
Stylo-hyoid. 
Mylo-hyoid. 
Genio-hyoid. 
Dissection.-To dissect these muscles a block should be placed beneath the back of the neck, 
and the head drawn backward and retained in that position. On the removal of the deep fascia 
the muscles are at once exposed. 
The Digastric consists of two fleshy bellies united by an intermediate rounded 
tendon. It is a small muscle, situated below the side of the body of the lower jaw, 
and extending in a curved form from the side of the head to the symphysis of the 
jaw. The posterior belly, longer than the anterior, arises from the digastric groove 
on the inner side of the mastoid process of the temporal bone, and passes downward, 
forward, and inward. The anterior belly arises from a depression on the inner side 
of the lower border of the jaw close to the symphysis, and passes downward and 
backward. The two bellies are inserted into a central tendon which perforates the 
Stylo-hyoid, and is held in connection with the side of the body and the greater 
cornu of the hyoid bone by a fibrous loop lined by a synovial membrane. A broad 
aponeurotic layer is given off from the tendon of the Digastric on each side, which 
is attached to the body and great cornu of the hyoid bone : this is termed the supra- 
hyoid aponeurosis. It forms a strong layer of fascia between the anterior portion 
of the two muscles, and a firm investment for the other muscles of the supra-hyoid 
region which lie deeper. 
The Digastric muscle divides the anterior superior triangle of the neck into two 
smaller triangles, the upper or submaxillary being bounded above by the lower jaw 
and mastoid process; below, by the two bellies of the Digastric muscle, the lower 
or superior carotid triangle being bounded above by the posterior belly of the 
Digastric; behind, by the Sterno-mastoid; below, by the Omo-hyoid. 
Relations.-By its superficial surface with the Platysma, Sterno- and Trachelo- 
mastoid, part of the Stylo-hyoid muscle, and the parotid gland; by its deep surface 
the anterior belly lies on the Mylo-hyoid; the posterior belly, on the Stylo-glossus, 
Stylo-pharyngeus, and Hyo-glossus muscles, the external carotid artery and its lin- 
gual and facial branches, the internal carotid artery, internal jugular vein, and 
hypoglossal nerve. 
The Stylo-hyoid is a small, slender muscle lying in front of and above the pos- 
terior belly of the Digastric. It arises from the outer surface of the styloid process 
near the base, and, passing downward and forward, is inserted into the body of the 
1 It is this action of the Thyro-hyoid muscle which, as Dr. Buchanan has pointed out, "causes or 
permits the folding back of the epiglottis over the upper orifice of the larynx" (Journ. of Anat. and 
Phys., 2d Series, No. III. p. 255). LINGUAL REGION. 
389 
hyoid bone just at its junction with the greater cornu and immediately above the 
Omo-hyoid. This muscle is perforated near its insertion by the tendon of the 
Digastric. 
Relations.-The same as the posterior belly of the Digastric. 
The Digastric and Stylo-hyoid should be removed, in order to expose the next muscle. 
The Mylo-hyoid is a flat triangular muscle situated immediately beneath the 
anterior belly of the Digastric, and forming, with its fellow of the opposite side, a 
muscular floor for the cavity of the mouth. It arises from the whole length of the 
mylo-hyoid ridge, from the symphysis in front to the last molar tooth behind. The 
posterior fibres pass obliquely forward, to be inserted into the body of the os hyoides. 
The middle and anterior fibres are inserted into a median fibrous raphe, where they 
join at an angle with the fibres of the opposite muscle. This median raphd is 
sometimes wanting; the muscular fibres of the two sides are then directly contin- 
uous with one another. 
Relations.-By its cutaneous surface with the Platysma, the anterior belly of 
the Digastric, the suprahyoid fascia, the submaxillary gland, submental vessels, and 
mylo-hyoid vessels and nerve ; by its deep or superior surface with the Denio-hyoid, 
part of the Hyo-glossus, and Stylo-glossus muscles, the hypoglossal and gustatory 
nerves, the sublingual gland, and the buccal mucous membrane. Wharton's duct 
curves round its posterior border in its passage to the mouth. 
Dissection.-The Mylo-hyoid should now be removed, in order to expose the muscles which 
lie beneath • this is effected by detaching it from its attachments to the hyoid bone and jaw, and 
separating it by a vertical incision from its fellow of the opposite side. 
The Genio-hyoid is a narrow, slender muscle situated immediately beneath1 the 
inner border of the preceding. It arises from the inferior genial tubercle on the 
inner side of the symphysis of the jaw, and passes downward and backward to be 
inserted into the anterior surface of the body of the os hyoides. This muscle lies 
in close contact with its fellow of the opposite side, and increases slightly in breadth 
as it descends. 
Relations.-It is covered by the Mylo-hyoid and lies on the Genio-hyo-glossus. 
Nerves.-The Digastric is supplied, its anterior belly, by the mylo-hyoid branch 
of the inferior dental; its posterior belly, by the facial; the Stylo-hyoid, by the 
facial; the Mylo-hyoid, by the mylo-hyoid branch of the inferior dental; the Genio- 
hyoid, by the hypoglossal. 
Actions.-This group of muscles performs two very important actions. They 
raise the hyoid bone, and with it the base of the tongue, during the act of degluti- 
tion ; or, when the hyoid bone is fixed by its depressors and those of the larynx, 
they depress the lower jaw. During the first act of deglutition, when the mass is 
being driven from the mouth into the pharynx, the hyoid bone, and with it the 
tongue, is carried upward and forward by the anterior belly of the Digastric, the 
Mylo-hyoid, and Genio-hyoid muscles. In the second act, when the mass is pass- 
ing through the pharynx, the direct elevation of the hyoid bone takes place by the 
combined action of all the muscles; and after the food has passed the hyoid bone 
is carried upward and backward by the posterior belly of the Digastric and Stylo- 
hyoid muscles, which assist in preventing the return of the morsel into the mouth. 
4. Lingual Region. 
Genio-hyo-glossus. 
Hyo-glossus. 
Lingualis. 
Stylo-glossus. 
Palato-glossus. 
Dissection.-After completing the dissection of the preceding muscles saw through the lower 
jaw just external to the symphysis. Then draw the tongue forward, and attach it by a stitch 
to the nose, and its muscles, which are thus put on the stretch, may be examined. 
1 This refers to the depth of the muscles from the skin in dissecting. In the erect position of the 
body each of these muscles lies above the preceding. 390 
MUSCLES AND FASCIAE. 
The Genio-hyo-glossus has received its name from its triple attachment to the 
jaw, hyoid bone, and tongue: it is a thin, flat, triangular muscle placed vertically 
on either side of the middle line, its apex corresponding with its point of attach- 
ment to the lower jaw, its base with its insertion into the tongue and hyoid bone. 
It arises by a short tendon from the superior genial tubercle on the inner side of 
the symphysis of the jaw, immediately above the Genio-hyoid; from this point the 
muscle spreads out in a fan-like form, the inferior fibres passing downward, to be 
inserted into the upper part of the body of the hyoid bone, a few being continued' 
into the side of the pharynx ; the middle fibres passing backward, and the superior 
ones upward and forward, to be attached to the whole length of the under surface 
of the tongue from the base to the apex. 
Relations.-By its internal surface it is in contact with its fellow of the oppo- 
site side, from which it is separated, at the back part of the tongue, by the fibrous 
septum, which extends through the middle of the organ; by its external surface 
with the inferior lingualis, Hyo-glossus, and Stylo-glossus, the lingual artery and 
hypoglossal nerve, the gustatory nerve, and sublingual gland; by its border 
with the mucous membrane of the floor of the mouth (fraenum linguae); by its lower 
border with the Genio-hyoid. 
The Hyo-glossus is a thin, flat, quadrilateral muscle which arises from the side 
of the body, the lesser cornu, and whole length of the greater cornu of the hyoid 
bone, and, passing almost vertically upward, is inserted into the side of the tongue 
Fig. 292. 
Muscles of the Tongue, left side. 
between the Stylo-glossus and Lingualis. Those fibres of this muscle which arise 
from the body (Basio-glossus) are directed upward and backward, overlapping 
those from the greater cornu (Kerato-glossus), which are directed obliquely for- 
ward. Those from the lesser cornu (Chondro-glossus) extend forward and outward 
along the side of the tongue under cover of the portion arising from the body. LINGUAL REGION. 
391 
The difference in the direction of the fibres of this muscle, and their separate 
origin from different parts of the hyoid bone, led Albinus and other anatomists to 
describe it as three muscles, under the names of the Basio-glossus, the Kerato- 
glossus, and the Chondro-glossus. Undoubtedly, the Chondro-glossus is distinct 
from the rest, and at the present day is described by some anatomists as a separate 
Fig. 293. 
hyoid bonu 
UNDINE. 
A Longitudinal Section of the Tongue near the middle line, to show the Superficial lingualis and the intrinsic 
vertical fibres. 
muscle. Sometimes it is separated from the rest of the muscle by a few fibres of 
the Genio-hyo-glossus passing to the side of the pharynx ; at other times it is 
altogether absent. 
Relations.-By its external surface with the Digastric, the Stylo-hyoid, Stylo- 
glossus, and Mylo-hyoid muscles, the gustatory and hypoglossal nerves, Wharton's 
duct, and the submaxillary gland; by its deep surface with the Genio-hyo-glossus, 
Lingualis, and Middle constrictor, the lingual vessels, and the glosso-pharyngeal 
nerve. 
The greater part of the muscular substance of the tongue is formed by its intrin- 
sic muscle, the Lingualis, inferior, superficial, transverse, and vertical. The infe- 
rior lingualis (Figs. 292, 293) is a longitudinal band of muscular fibres situated on 
the under surface of the tongue, lying in the interval between the Hyo-glossus and 
the Genio-hyo-glossus, and extending from the base to the apex of the organ. Pos- 
teriorly, some of its fibres are lost in the base of the tongue, and others are occa- 
sionally attached to the hyoid 
bone. It blends with the fibres 
of the Stylo-glossus in front of 
the Hyo-glossus, and is continued 
forward as far as the apex of the 
tongue. It is in relation, by its 
under surface, with the ranine 
artery. The superficial lingualis 
(Fig. 293) consists of fibres run- 
ning more or less longitudinally 
along the dorsum of the tongue 
beneath the mucous membrane 
from base to apex, and blending 
with the deeper fibres. At the 
sides of the tongue these fibres 
are crossed by those of the Palato- 
and Hyo-glossus. Between these two sets of fibres are found transverse fibres (Fig. 
294) which arise from the median septum and blend with the fibres of the Palato- 
glossus and other muscles, as well as a large number of vertical fibres. The vertical 
fibres are arranged somewhat parallel with those of the Genio-hyo-glossus, with which 
Fig. 294. 
A Transverse Section of the Tongue, showing the various intrin- 
sic and extrinsic muscles in their relative positions: the in- 
trinsic vertical fibres and the ranine artery are removed on 
one side and shown on the other. 392 
MUSCLES AND FASCIxE. 
many of those near the middle line are continuous; they extend from the upper to 
the lower surface of the tongue, decussating with the fibres of the other muscles, 
and especially with the transverse. The interstices of the muscular fibres are filled 
with a large quantity of fat and glandular tissue. 
A very distinct fibrous septum exists between the two halves of the tongue, so 
that the anastomoses between the two lingual arteries are not very free-a fact often 
illustrated by injecting one half of the tongue with colored size, while the other is 
left uninjected or is injected of a different color. 
The Stylo-glossus, the shortest and smallest of the three styloid muscles, arises 
from the anterior and outer side of the styloid process near its apex, and from the 
stylo-maxillary ligament, to which its fibres in most cases are attached by a thin 
aponeurosis. Passing downward and forward, so as to become nearly horizontal in 
its direction, it divides upon the side of the tongue into two portions-one longitu- 
dinal, which is inserted along the side of the tongue, blending with the fibres of the 
Lingualis in front of the Hyo-glossus; the other oblique, which overlaps the Hyo- 
glossus muscle and decussates with its fibres. 
Relations.-By its external surface, from above downward, with the parotid 
gland, the Internal pterygoid muscle, the sublingual gland, the gustatory nerve, and 
the mucous membrane of the mouth; by its internal surface with the tonsil, the 
Superior constrictor, and the Hyo-glossus muscle. 
The Palatoglossus or Constrictor isthmi faucium, although it is one of the 
muscles of the tongue, serving to draw its base upward during the act of deglutition, 
is more nearly associated with the soft palate both in its situation and function; it 
will consequently be described with that group of muscles. 
Nerves.-The Palato-glossus is supplied by the palatine branches of Meckel's 
ganglion; the Lingualis, according to some authors, by the chorda tympani; the 
remaining muscles of this group, by the hypoglossal. 
Actions.-The movements of the tongue, although numerous and complicated, 
may be understood by carefully considering the direction of the fibres of its muscles. 
The G-enio-hyo-glossi by means of their posterior and inferior fibres draw upward 
the hyoid bone, bringing it and the base of the tongue forward, so as to protrude 
the apex from the mouth. The anterior fibres draw the tongue back into the mouth. 
In their whole length these two muscles, acting along the middle line of the tongue, 
draw it downward, so as to make it concave from side to side, forming a channel 
along which fluids may pass toward the pharynx, as in sucking. The Hyo-glossi 
muscles draw down the sides of the tongue, so as to render it convex from side to 
side. The Linguales, superficial and inferior, by drawing downward the centre and 
apex of the tongue render it convex from before backward. The Palato-glossi draw 
the base of the tongue upward, and the Stylo-glossi upward and backward. 
5. Pharyngeal Region. 
Constrictor inferior. 
Constrictor medius. 
Constrictor superior. 
Stylo-pharyngeus. 
Palato-pharyngeus. (See next section.) 
(Fig. 295).-In order to examine the muscles of the pharynx, cut through the tra- 
chea and oesophagus just above the sternum, and draw them upward by dividing the loose 
areolar tissue connecting the pharynx with the front of the vertebral column. The parts being 
drawn well forward, apply the edge of the saw immediately behind the styloid processes and 
saw the base of the skull through from below upward. The pharynx and mouth should then be 
stuffed with tow, in order to distend its cavity and render the muscles tense and easier of dis- 
section. 
The Inferior Constrictor, the most superficial and thickest of the three con- 
strictors, arises from the side of the cricoid and thyroid cartilages. To the cricoid 
cartilage it is attached in the interval between the Crico-thyroid muscle in front and 
the articular facet for the thyroid cartilage behind. To the thyroid cartilage it is 
attached along the oblique line on the side of the great ala, the cartilaginous surface PHARYNGEAL REGION. 
393 
behind it nearly as far as its posterior border, and to the inferior cornu. From 
these attachments the fibres spread backward and inward, to be inserted into the 
fibrous raphe in the posterior median line 
of the pharynx. The inferior fibres are 
horizontal, and continuous with the fibres 
of the oesophagus; the rest ascend, in- 
creasing in obliquity, and overlap the 
Middle constrictor. The superior laryn- 
geal nerve and artery pass near the upper 
border, and the inferior or recurrent lar- 
yngeal beneath the lower border of this 
muscle, previous to their entering the 
larynx. 
Relations.-It is covered by a dense 
cellular membrane which surrounds the 
entire pharynx. Behind it is in relation 
with the vertebral column and the Longus 
colli muscle; laterally, with the thyroid 
gland, the common carotid artery, and the 
Sterno-thyroid muscle; by its internal 
surface, with the Middle constrictor, the 
Stylo-pharyngeus, Palato-pharyngeus, the 
fibrous coat and mucous membrane of the 
pharynx. 
The Middle Constrictor is a flattened, 
fan-shaped muscle smaller than the pre- 
ceding. It arises from the whole length 
of the upper surface of the greater cornu 
of the hyoid bone, from the lesser cornu, 
and from the stylo-hyoid ligament. The 
fibres diverge from their origin, the lower 
ones descending beneath the Inferior con- 
strictor, the middle fibres passing transversely, and the upper fibres ascending and 
overlapping the Superior constrictor. The muscle is inserted into the posterior 
median fibrous raphd, blending in the middle line with that of the opposite side. 
Relations.-This muscle is separated from the Superior constrictor by the 
glosso-pharyngeal nerve and the Stylo-pharyngeus muscle*, and from the Inferior 
constrictor by the superior laryngeal nerve. Behind it lies on the vertebral column, 
the Longus colli, and the Rectus capitis anticus major. On each side it is in relation 
with the carotid vessels, the pharyngeal plexus, and some lymphatic glands. Near 
its origin it is covered by the Hyo-glossus, from which it is separated by the lingual 
vessels, It lies upon the Superior constrictor, the Stylo-pharyngeus, the Palato- 
pharyngeus, the fibrous coat, and the mucous membrane of the pharynx. 
The Superior Constrictor is a quadrilateral muscle thinner and paler than the 
other constrictors, and situated at the upper part of the pharynx. It arises from 
the lower third of the posterior margin of the internal pterygoid plate and its 
hamular process, from the contiguous portion of the palate bone and the reflected 
tendon of the Tensor palati muscle, from the pterygo-maxillary ligament, from the 
alveolar process above the posterior extremity of the mylo-hyoid ridge, and by a 
few fibres from the side of the tongue in connection with the Genio-hyo-glossus. 
From these points the fibres curve backward, to be inserted into the median raphd, 
being also prolonged by means of a fibrous aponeurosis to the pharyngeal spine on 
the basilar process of the occipital bone. The superior fibres arch beneath the 
Levator palati and the Eustachian tube, the interval between the upper border of 
the muscle and the basilar process being deficient in muscular fibres and closed by 
fibrous membrane. This interval is known as the sinus of Morgagni. 
Relations.-By its outer surface with the vertebral column, the internal caro- 
Fig. 295. 
Muscles of the Pharynx, external view. 394 
MUSCLES AND FASCIAL 
tid artery, the internal jugular vein, the pneumogastric, glosso-pharyngeal, and 
spinal accessory nerves, the sympathetic, the hypoglossal nerve, the Aliddle con- 
strictor, which overlaps it, and the Stylo-pharyngeus. It covers the Palato-pharyn- 
geus and the tonsil, and is lined by the fibrous coat and by mucous membrane. 
The Stylo-pharyngeus is a long, slender muscle, round above, broad and thin 
below. It arises from the inner side of the base of the styloid process, passes down- 
ward along the side of the pharynx between the Superior and Middle constrictors, 
and spreads out beneath the mucous membrane, where some of its fibres are lost in 
the Constrictor muscles, and others, joining with the Palato-pharyngeus, are inserted 
into the posterior border of the thyroid cartilage. The glosso-pharyngeal nerve runs 
on the outer side of this muscle and crosses over it in passing forward to the tongue. 
Relations.-Externally with the Stylo-glossus muscle, the external carotid 
artery, the parotid gland, and the Middle constrictor; internally with the internal 
carotid, the internal jugular vein, the Superior constrictor, Palato-pharyngeus, and 
mucous membrane. 
Nerves.-The Constrictors are supplied by branches from the pharyngeal 
plexus; the Stylo-pharyngeus, by the glosso-pharyngeal nerve; and the Inferior 
constrictor, by an additional branch from the external laryngeal nerve and by the 
recurrent laryngeal. 
Actions.-When deglutition is about to be performed the pharynx is drawm 
upward and dilated in different directions to receive the morsel propelled into it 
from the mouth. The Stylo-pharyngei, which are much farther removed from 
one another at their origin than at their insertion, draw the sides of the pharynx 
upward and outward, its breadth in the antero-posterior direction being increased 
by the larynx and tongue being carried forward in their ascent. As soon as the 
morsel is received in the pharynx the Elevator muscles relax, the bag descends, 
and the Constrictors contract upon the morsel and convey it gradually downward 
into the oesophagus. Besides its action in deglutition the pharynx also exerts an 
important influence in the modulation of the voice, especially in the production of 
the higher tones. 
6. Palatal Region. 
Levator palati. 
Tensor palati. 
Azygos uvulie. 
Palato-glossus. 
Palato-pharyngeus. 
Dissection (Fig. 296).-Lay open the pharynx from behind by a vertical incision extending 
from its upper to its lower .part, and partially divide the occipital attachment by a transverse 
incision on each side of the vertical one; the posterior surface of the soft palate is then exposed. 
Having fixed the uvula so as to make it tense, the mucous membrane and glands should be 
carefully removed from the posterior surface of the soft palate, and the muscles of this part are 
at once exposed. 
The Levator palati is a long, thick, rounded muscle placed on the outer side 
of the posterior nares. It arises from the under surface of the apex of the petrous 
portion of the temporal bone and from the adjoining cartilaginous portion of the 
Eustachian tube; after passing into the pharynx, above the upper concave margin 
of the Superior constrictor, it descends obliquely downward and inward, its fibres 
spreading out on the posterior surface of the soft palate as far as the middle line, 
where they blend with those of the opposite side. 
Relations.-Externally with the Tensor palati and Superior constrictor; inter- 
nally with the mucous membrane of the pharynx; posteriorly with the mucous lining 
of the soft palate. This muscle must be removed and the pterygoid attachment of 
the Superior constrictor dissected away in order to expose the next muscle. 
The Circumflexus, or Tensor palati, is a broad, thin, ribbon-like muscle 
placed on the outer side of the preceding, and consisting of a vertical and a hori- 
zontal portion. The vertical portion arises by a broad, thin, and flat lamella from 
the scaphoid fossa at the base of the internal pterygoid plate; from the spine of the 
sphenoid, the vaginal process of the temporal bone, and the anterior aspect of the 
cartilaginous portion of the 'Eustachian tube: descending vertically between the PALATAL REGION. 
395 
internal pterygoid plate and the inner surface of the Internal pterygoid muscle, it 
terminates in a tendon which winds round the hamular process, being retained in 
this situation by some of the fibres of origin of the Internal pterygoid muscle, and 
lubricated by a bursa. The tendon or horizontal portion then passes horizontally 
inward, and expands into a broad aponeurosis on the anterior surface of the soft 
palate, which unites in the median line with the aponeurosis of the opposite muscle, 
the fibres being attached in front to the transverse ridge on the horizontal portion 
of the palate bone. 
Relations.-Externally with the Internal pterygoid; internally with the Leva- 
tor palati, from which it is separated by the Superior constrictor, and with the inter- 
Fig. 296. 
Muscles of the Soft Palate, the pharynx being laid open from behind. 
nal pterygoid plate. In the soft palate its aponeurotic expansion is anterior to that 
of the Levator palati, being covered by mucous membrane. 
The Azygos [or Levator] uvulae is not a single muscle, as would be inferred 
from its name, but a pair of narrow, cylindrical fleshy fasciculi placed side by side 
in the median line of the soft palate. Each muscle arises from the posterior nasal 
spine of the palate bone and from the contiguous tendinous aponeurosis of the soft 
palate, and descends to be inserted into the uvula. 
Relations.-Anteriorly with the tendinous expansion of the Levatores palati; 
behind with the mucous membrane. 
[Actions.-The actions of these muscles, which in general are well indicated 
by their names, have been most ingeniously studied by a new method by Dr. Har- 
rison Allen (Trans. Coll. Phys. Phila., 1884). He uses the "Palate myograph," 
a rod passing through the nose, the inner end resting on the palate and the outer 
against a revolving drum. The student is referred to this paper for the results.] 396 
MUSCLES AND FASCIAL 
The two next muscles are exposed by removing the mucous membrane from the pillars of the 
soft palate throughout nearly theii- whole extent. 
The Palato-glossus (Constrictor isthmi faucium) is a small fleshy fasciculus, 
narrower in the middle than at either extremity, forming, with the mucous mem- 
brane covering its surface, the anterior pillar of the soft palate. It arises from the 
anterior surface of the soft palate on each side of the uvula, and, passing downward, 
forward, and outward in front of the tonsil, is inserted into the side and dorsum of 
the tongue,where it blends with the fibres of the Stylo-glossus muscle. In the soft 
palate the fibres of this muscle are continuous with those of the muscle of the oppo- 
site side. 
The Palato-pharyngeus is a long, fleshy fasciculus, narrower in the middle than 
at either extremity, forming, with the mucous membrane covering its surface, the 
posterior pillar of the soft palate. It is separated from the preceding by an angular 
interval, in which the tonsil is lodged. It arises from the soft palate by an expanded 
fasciculus, which is divided into two parts by the Levator palati and Azygos uvulae. 
The anterior fasciculus, the thicker, lies in the soft palate between the Levator and 
Tensor, and joins in the middle line the corresponding part of the opposite muscle; 
the posterior fasciculus lies in contact with the mucous membrane, and also joins 
with the corresponding muscle in the middle line. Passing outward and downward 
behind the tonsil, the Palato-pharyngeus joins the Stylo-pharyngeus, and is inserted 
with that muscle into the posterior border of the thyroid cartilage, some of its fibres 
being lost on the side of the pharynx, and others passing across the middle line pos- 
teriorly to decussate with the muscle of the opposite side. Connected with the Pal- 
ato-pharyngeus there is sometimes found a slip arising above from the Eustachian 
tube and called the Salpingo-pharyngeus. 
Relations.-In the soft palate its posterior surface is covered by mucous mem- 
brane, from which it is separated by a layer of palatine glands. By its superior 
border it is in relation with the Levator palati. Where it forms the posterior pillar 
of the fauces it is covered by mucous membrane, excepting on its outer surface. In 
the pharynx it lies between the mucous membrane and the Constrictor muscles. 
In a dissection of the soft palate from its posterior or nasal surface to its anterior 
or oral surface the muscles would be exposed in the following order-viz. the poste- 
rior fasciculus of the Palato-pharyngeus, covered over by the mucous membrane 
reflected from the floor of the nasal fossae; the Azygos uvulae; the Levator palati; 
the anterior fasciculus of the Palato-pharyngeus; the aponeurosis of the Tensor 
palati; and the Palato-glossus, covered over by a reflection from the oral mucous 
membrane. 
Nerves.-The Tensor palati is supplied by a branch from the otic ganglion; the 
Levator palati, Azygos uvulae, and other muscles, by the descending palatine branches 
from Meckel's ganglion. These nerves are derived primarily from the facial. 
Actions.-During the first stage of deglutition the morsel of food is driven back 
into the fauces by the pressure of the tongue against the hard palate, the base of 
the tongue being at the same time retracted and the larynx raised with the pharynx 
and carried forward under it. During the second stage the epiglottis is pressed over 
the superior aperture of the larynx, and the morsel glides past it; then the Palato- 
glossi muscles, the constrictors of the fauces, contract behind the food; the soft pal- 
ate is slightly raised by the Levator palati and made tense by the Tensor palati; 
and the Palato-pharyngei contract and come nearly together, the uvula filling up the 
slight interval between them. By these means the food is prevented passing into 
the upper part of the pharynx or the posterior nares; at the same time the latter 
muscles form an inclined plane, directed obliquely downward and backward, along 
the under surface of which the morsel descends into the lower part of the pharynx. 
Surgical Anatomy.-The muscles of the soft palate should be carefully dissected, the 
relations they bear to the surrounding parts especially examined, and their action attentively 
studied upon the dead subject, as the surgeon is required to divide one or more of these muscles 
in the operation of staphylorraphy. Sir W. Fergusson was the first to show that in the congen- 
ital deficiency called cleft palate the edges of the fissure are forcibly separated by the action of ANTERIOR VERTEBRAL REGION. 
397 
the Levatores palati and Palato-pharyngei muscles, producing very considerable impediment to 
the healing process after the performance of the operation for uniting their margins by adhe- 
sion ; he consequently recommended the division of these muscles as one of the most important 
steps in the operation. This he effected by an incision made with a curved knife introduced 
behind the soft palate. The incision is to be halfway between the hamular process and Eusta- 
chian tube, and perpendicular to a line drawn between them. This incision perfectly accom- 
plishes the division of the Levator palati. The Palato-pharyngeus may be divided by cutting 
across the posterior pillar of the soft palate, just below the tonsil, with a pair of blunt-pointed 
curved scissors; and the anterior pillar may be divided also. To divide the Levator palati the 
plan recommended by Mr. Pollock is to be greatly preferred. The soft palate being put upon 
the stretch, a double-edged knife is passed through it just on the inner side of the hamular pro- 
cess and above the line of the Levator palati. The handle being now alternately raised and 
depressed, a sweeping cut is made along the posterior surface of the soft palate, and the knife 
withdrawn, leaving only a small opening in the mucous membrane on the anterior surface. If 
this operation is performed on the dead body and the parts afterward dissected, the Levator 
palati will be found completely divided. 
7. Anterior Vertebral Region. 
Rectus capitis anticus major. 
Rectus capitis anticus minor. 
Rectus lateralis. 
Longus colli. 
The Rectus capitis anticus major (Fig. 297), broad and thick above, narrow 
below, appears like a continuation upward of the Scalenus anticus. It arises by 
four tendinous slips from the 
anterior tubercles of the 
transverse processes of the 
third, fourth, fifth, and sixth 
cervical vertebrae, and as- 
cends, converging toward its 
fellow of the opposite side, to 
be inserted into the basilar 
process of the occipital bone. 
Relations.-By its ante- 
rior surface with the phar- 
ynx, the sympathetic nerve, 
and the sheath enclosing the 
carotid artery, internal jugu- 
lar vein, and pneumogastric 
nerve; by its posterior sur- 
face, with the Longus colli, 
the Rectus anticus minor, 
and the upper cervical ver- 
tebrae. 
The Rectus capitis an- 
ticus minor is a short flat 
muscle situated immediately 
behind the upper part of the 
preceding. It arises from the 
anterior surface of the lateral 
mass of the atlas and from the 
root of its transverse process, 
and, passing obliquely up- 
ward and inward, is inserted 
into the basilar process im- 
mediately behind the preced- 
ing muscle. 
Relations.-By its ante- 
rior surface with the Rectus capitis anticus major; by its posterior surface with 
the front of the occipito-atloid articulation; externally with the superior cervical 
ganglion of the sympathetic. 
Fig. 297. 
The Prevertebral Muscles. MUSCLES AND FASCIAE. 
398 
The Rectus lateralis is a short flat muscle which arises from the upper surface 
of the transverse process of the atlas, and is inserted into the under surface of the 
jugular process of the occipital bone. 
Relations.-By its anterior surface with the internal jugular vein ; by its pos- 
terior surface with the vertebral artery; on its outer side lies the occipital artery, 
on its inner side the suboccipital nerve. 
The Longus colli is a long flat muscle situated on the anterior surface of the 
spine, between the atlas and the third dorsal vertebra. It is broad in the middle, 
narrow and pointed at each extremity, and consists of three portions-a superior 
oblique, an inferior oblique, and a vertical portion. The superior oblique portion 
arises from the anterior tubercles of the transverse processes of the third, fourth, 
and fifth cervical vertebrae, and, ascending obliquely inward, is inserted by a nar- 
row tendon into the tubercle on the anterior arch of the atlas. The inferior oblique 
portion, the smallest part of the muscle, arises from the front of the bodies of the 
first two or three dorsal vertebrae, and, ascending obliquely outward, is inserted 
into the anterior tubercles of the transverse processes of the fifth and sixth cer- 
vical vertebrae. The vertical portion lies directly on the front of the spine, and is 
extended between the front of the bodies of the lower three cervical and the upper 
three dorsal vertebrae below and the front of the bodies of the second, third, and 
fourth cervical vertebrae above. 
Relations.-By its anterior surface with the pharynx, the oesophagus, sympa- 
thetic nerve, the sheath of the great vessels of the neck, the inferior thyroid artery, 
and recurrent laryngeal nerve; by its posterior surface with the cervical and dorsal 
portions of the spine. Its inner border is separated from the opposite muscle by a 
considerable interval below, but they approach each other above. 
8. Lateral Vertebral Region. 
Scalenus anticus. 
Scalenus posticus. 
Scalenus medius. 
The Scalenus anticus is a conical-shaped muscle situated deeply at the side of 
the neck, behind the Sterno-mastoid. It arises by a narrow, flat tendon from the 
tubercle on the inner border and upper surface of the first rib, and, ascending 
almost vertically, is inserted into the anterior tubercles of the transverse processes 
of the third, fourth, fifth, and sixth cervical vertebrae. The lower part of this 
muscle separates the subclavian artery and vein, the latter being in front, and the 
former, with the brachial plexus, behind. 
Relations.-In front with the clavicle, the Subclavius, Sterno-mastoid, and 
Omo-hyoid muscles, the transversalis colli, and ascending cervical arteries, the sub- 
clavian vein, and the phrenic nerve; by its posterior surface with the pleura, the 
subclavian artery, and brachial plexus of nerves. It is separated from the Longus 
colli on the inner side by the vertebral artery. 
The Scalenus medius, the largest and longest of the three Scaleni, arises by a 
broad origin from the upper surface of the first rib, behind the groove for the sub- 
clavian artery, as far back as the tubercle, and, ascending along the side of the 
vertebral column, is inserted by separate tendinous slips into the posterior tubercles 
of the transverse processes of the lower six cervical vertebrae. It is separated from 
the Scalenus anticus by the subclavian artery below and the cervical nerves above. 
The posterior thoracic, or nerve of Bell, is formed in the substance of the Scalenus 
medius and emerges from it. 
Relations.-By its anterior surface with the Sterno-mastoid; it is crossed by 
the clavicle, the Omo-hyoid muscle, subclavian artery, and the cervical nerves. To 
its outer side is the Levator anguli scapulae and the Scalenus posticus muscle. 
The Scalenus posticus, the smallest of the three Scaleni, arises by a thin ten- 
don from the outer surface of the second rib, behind the attachment of the Serratus 
magnus, and, enlarging as it ascends, is inserted by two or three separate tendons 
into the posterior tubercles of the transverse processes of the lower two or three MUSCLES OF THE BACK. 
399 
cervical vertebrae. This is the most deeply placed of the three Scaleni, and is occa- 
sionally blended with the Scalenus medius. 
Nerves.-The Rectus capitis anticus major and minor and the Rectus lateralis 
are supplied by the suboccipital and deep internal branches of the cervical plexus; 
the Longus colli and Scaleni by anterior branches of the lower cervical nerves before 
they form the brachial plexus. 
Actions.-The Rectus anticus major and minor are the direct antagonists of the 
muscles at the back of the neck, serving to restore the head to its natural position 
after it has been drawn backward. These muscles also serve to flex the head, and 
from their obliquity rotate it, so as to turn the face to one or the other side. The 
Longus colli flexes and slightly rotates the cervical portion of the spine. The Sca- 
leni muscles, taking their fixed point from below, bend the spinal column to one or 
the other side. If the muscles of both sides act, lateral movement is prevented, 
but the spine is slightly flexed. When they take their fixed point from above they 
elevate the first and second ribs, and are therefore inspiratory muscles. The Rectus 
lateralis, acting on one side, bends the head laterally. 
MUSCLES AND FASCLE OF THE TRUNK. 
The Muscles of the Trunk may be arranged in four groups: the muscles of the 
Back, of the Abdomen, of the Thorax, and of the Perineum.1 
Muscles of the Back. 
The Muscles of the Back are very numerous, and may be subdivided into five 
layers: 
First Layer. 
Longissimus dorsi. 
Spinalis dorsi. 
Trapezius. 
Latissimus dorsi. 
Cervical Region. 
Second Layer. 
Cervicalis ascendens. 
Transversalis colli. 
Trachelo-mastoid. 
Complexus. 
Biventer cervicis. 
Spinalis colli. 
Levator anguli scapulae. 
Rhomboideus minor. 
Rhomboideus major. 
Serratus posticus superior. 
Serratus posticus inferior. 
Splenius capitis. 
Splenius colli. 
Third Layer. 
Fifth Layer. 
Semispinalis dorsi. 
Semispinalis colli. 
Multifidus spinae. 
Rotatores spinae. 
Supraspinales. 
Interspinales. 
Extensor coccygis. 
In tertrans versales. 
Rectus capitis posticus major. 
Rectus capitis posticus minor. 
Obliquus capitis superior. 
Obliquus capitis inferior. 
Fourth Layer. 
Sacral and Lumbar Regions. 
Erector spinae. 
Dorsal Region. 
Sacro-lumbalis. 
Musculus accessorius ad sacro-lumbalem. 
First Layer. 
Trapezius. 
Latissimus dorsi. 
Dissection (Fig. 298).-Place the body in the prone position, with the arms extended over 
the sides of the table, and the chest and abdomen supported by several blocks, so as to render 
1 The muscles of the perineum are described with the Surgical Anatomy of this region at the end 
of the volume. 400 
MUSCLES AND FASCIAE. 
the muscles tense. Then make an incision along the middle line of the hack from the occipital 
protuberance to the coccyx. Make a transverse incision from the upper end of this to the mas- 
toid process, and a third incision from its lower end, along the crest of the ilium, to about its 
middle. This large intervening space should, for convenience of dissection, be subdivided by a 
fourth incision, extending obliquely from the spinous process of the last dorsal vertebra upward 
and outward to the acromion process. This incision corresponds with the lower border of the 
Trapezius muscle. The flaps of integument are then to be removed in the direction shown in 
the figure. 
The superficial fascia is exposed upon removing the skin from the back. It forms a layer 
of considerable thickness and strength, in which a quantity of granular pinkish fat is contained. 
It is continuous with the superficial fascia in other parts of the body. The deep fascia is a 
dense fibrous layer attached to the occipital bone, the spines of the vertebrae, the crest of the 
ilium, and the spine of the scapula. It covers over the superficial muscles, forming sheaths for 
them, and is continuous in the neck at the anterior border of the Trapezius with the deep cer- 
vical fascia; in the thorax, with the deep fascia of the axilla and chest; and in the abdomen, 
with that covering the abdominal muscles. 
The Trapezius (Fig. 300) is a broad, flat, triangular muscle placed immediately 
beneath the skin and fascia, and covering the upper and back part of the neck and 
shoulders. It arises from the inner third of the 
superior curved line of the occipital bone, from 
the ligamentum nuchae, the spinous process of the 
seventh cervical, and those of all the dorsal ver- 
tebrae, and from the corresponding portion of the 
supraspinous ligament. From this origin the su- 
perior fibres proceed downward and outward, the 
inferior ones upward and outward, and the mid- 
dle fibres horizontally, and are inserted, the su- 
perior ones into the outer third of the posterior 
border of the clavicle, the middle fibres into the 
inner margin of the acromion process and into 
the superior lip of the crest of the spine of the 
scapula. The inferior fibres converge near the 
scapula, and are attached to a triangular apo- 
neurosis which glides over a smooth surface at the 
inner extremity of the spine, and is inserted into 
a tubercle at the outer part of the surface. The 
Trapezius is fleshy in the greater part of its ex- 
tent, but tendinous at its origin and insertion. 
At its occipital origin it is connected to the bone 
by a thin fibrous lamina firmly adherent to the 
skin and wanting the lustrous, shining appear- 
ance of aponeurosis. At its origin from the 
spines of the vertebrae it is connected to the 
bones by means of a broad semielliptical apo- 
neurosis which occupies the space between the 
sixth cervical and the third dorsal vertebrae, and 
forms, with the aponeurosis of the opposite mus- 
cle, a tendinous ellipse. The rest of the muscle 
arises by numerous short tendinous fibres. If the Trapezius is dissected on both 
sides, the two muscles resemble a trapezium or diamond-shaped quadrangle-two 
angles corresponding to the shoulders, a third to the occipital protuberance, and the 
fourth to the spinous process of the last dorsal vertebra. 
The clavicular insertion of this muscle varies as to the extent of its attach- 
ment : it sometimes advances as far as the middle of the clavicle, and may even 
become blended with the posterior edge of the Sterno-mastoid or overlap it. 
This should be borne in mind in the operation for tying the third part of the 
subclavian artery. 
Relations.-By its superficial surface with the integument; by its deep sur- 
face in the neck with the Complexus, Splenius, Levator anguli scapulae, and 
Fig. 298. 
Dissection of the Muscles of the Back. MUSCLES OE THE BACK. 
401 
Rhomboideus minor; in the back with the Rhomboideus major, Supraspinatus, 
Infraspinatus, the lumbar fascia (which separates it from the Erector spinae), and 
the Latissimus dorsi. The spinal accessory nerve and the superficial cervical 
artery pass beneath the anterior border of this muscle near the clavicle. The 
anterior margin of its cervical portion forms the posterior boundary of the poste- 
rior triangle of the neck, the other boundaries being the Sterno-mastoid in front 
and the clavicle below. 
The Ligamentiim nuchee (Figs. 299, 300) is a thin band of condensed cellulo- 
fibrous membrane placed in the line of union between the two Trapezii in the 
neck. It extends from the external occipital protuberance to the spinous process 
of the seventh cervical vertebra, where it is continuous with the supraspinous 
ligament. From its anterior surface a fibrous slip is given off to the spinous process 
of each of the cervical vertebrae, so as to form a septum between the muscles 
on each side of the neck. In man it is merely the rudiment of an important 
elastic ligament which in some of the lower animals serves to sustain the w'eight 
of the head.1 
The Latissimus dorsi is a broad flat muscle which covers the lumbar and the 
lower half of the dorsal regions, and is gradually contracted into a narrow fasciculus 
at its insertion into the humerus. It arises by an aponeurosis from the spinous pro- 
cesses of the six inferior dorsal, from those of 
the lumbar and sacral vertebrae, and from the 
supraspinous ligament. Over the sacrum the 
aponeurosis of this muscle blends with the 
tendon of the Erector spinae. It also arises 
from the external lip of the crest of the ilium 
behind the origin of the External oblique, and 
by fleshy digitations from the three or four 
lower ribs, which are interposed between simi- 
lar processes of the External oblique muscle 
(Fig. 303, p. 413). From this extensive origin 
the fibres pass in different directions, the upper 
ones horizontally, the middle obliquely upward, 
and the lower vertically upward, so as to con- 
verge and form a thick fasciculus which crosses 
the inferior angle of the scapula and occasion- 
ally receives a few fibres from it. The muscle 
then curves around the lower border of the 
Teres major, and is twisted upon itself, so that 
the superior fibres become at first posterior and 
then inferior, and the vertical fibres at first 
anterior and then superior. It then terminates 
in a short quadrilateral tendon about three 
inches in length, which, passing in front of the 
tendon of the Teres major, is inserted into the 
inner lip and into the bottom of the bicipital 
groove of the humerus, its insertion extending higher on the humerus than that of 
the tendon of the Pectoralis major. The lower border of the tendon of this muscle 
is united with that of the Teres major, the surfaces of the two being separated by a 
bursa; another bursa is sometimes interposed between the muscle and the inferior 
angle of the scapula. 
A muscular slip, varying from three to four inches in length and from one-quarter to three- 
quarters of an inch in breadth, occasionally arises from the upper edge of the Latissimus dorsi 
about the middle of the posterior fold of the axilla, and crosses the axilla in front of the axil- 
lary vessels and nerves to join the under surface of the tendon of the Pectoralis major, the 
Coraco-brachialis, or the fascia over the Biceps. The position of this abnormal slip is a point 
[Fig. 299. 
OCCIPITAL BONE 
The Ligamentum Nuchae (Henle).] 
E1 Shepherd of Montreal has recorded one case in which the upper part of this ligament was 
replaced by strong muscular fibres (Brooklyn Annals of Anatomy and Surgery, 1881, iv. 111).] 402 
MUSCLES AND FASCIAE. 
Fig. 300. 
Muscles of the Back. On the left side is exposed the first layer; on the right side, the second layer find 
part of the third. MUSCLES OF THE BACK. 
403 
of interest in its relation to the axillary artery, as it crosses the vessel just above the spot 
usually selected for the application of a ligature, and may mislead the surgeon during the ope- 
ration. It may be easily recognized by the transverse direction of its fibres. Dr. Struthers 
found it in 8 out of 105 subjects, occurring seven times on both sides. 
Relations.-Its superficial surface is subcutaneous, excepting at its upper part, 
where it is covered by the Trapezius, and at its insertion, where its tendon is crossed 
by the axillary vessels and the brachial plexus of nerves. By its deep surface it is 
in relation with the Erector spinm, the Serratus posticus inferior, the lower external 
intercostal muscles and ribs, inferior angle of the scapula, Rhomboideus major, Infra- 
spinatus, and Teres major. Its outer margin is separated below from the External 
oblique by a small triangular interval; and another triangular interval exists 
between its upper border and the margin of the Trapezius, in which the Rhom- 
boideus major muscle is exposed. 
Nerves.-The Trapezius is supplied by the spinal accessory and by branches 
from the anterior divisions of the third and fourth cervical nerves; the Latissimus 
dorsi, by the long subscapular nerve. 
Second Layer 
Levator anguli scapulae. 
Rhomboideus major. 
Rhomboideus minor. 
Dissection.-The Trapezius must be removed, in order to expose the next layer ; to effect this, 
detach the muscle from its attachment to the clavicle and spine of the scapula and turn it back 
toward the spine. 
The Levator angnli scapulae is situated at the back part and side of the neck. 
It arises by three, four, or five tendinous slips from the posterior tubercles of the 
transverse processes of the three, four, or five upper cervical vertebrae; these, 
becoming fleshy, are united so as to form a flat muscle, which, passing downward 
and backward, is inserted into the posterior border of the scapula, between the 
superior angle and the triangular smooth surface at the root of the spine. 
Relations.-By its superficial (anterior') surface with the integument, Trapezius, 
and Sterno-mastoid; by its deep (posterior) surface with the Splenius colli, Trans- 
versalis colli, Cervicalis ascenclens, and Serratus posticus superior, and with the 
transversalis colli and posterior scapular arteries. 
The Rhomboideus minor arises from the ligamentum nuchse and spinous pro- 
cesses of the seventh cervical and first dorsal vertebrae. Passing downward and 
outward, it is inserted into the margin of the triangular smooth surface at the root 
of the spine of the scapula. This small muscle is usually separated from the Rhom- 
boideus major by a slight cellular interval. 
The Rhomboideus major is situated immediately below the preceding, the 
adjacent margins of the two being occasionally united. It arises by tendinous fibres 
from the spinous processes of the four or five upper dorsal vertebrae and the supra- 
spinous ligament, and is inserted into a narrow tendinous arch attached above to the 
triangular surface near the spine; below, to the inferior angle, the arch being con- 
nected to the border of the scapula by a thin membrane. When the arch extends, 
as it occasionally does, but a short distance, the muscular fibres are inserted into the 
scapula itself. 
Relations.-By their superficial (posterior) surface with the integument and 
Trapezius, the Rhomboideus major with the Latissimus dorsi; by their deep (ante- 
rior) surface with the Serratus posticus superior, posterior scapular artery, prolonga- 
tions from the Erector spinse, the intercostal muscles, and ribs. 
Nerves.-The Rhomboid muscles are supplied by branches from the fifth cervi- 
cal nerve; the Levator anguli scapulae, by the interior division of the third and 
fourth cervical nerves. 
Actions.-The movements effected by the preceding muscles are numerous, as 
may be conceived from their extensive attachment. If the head is fixed, the upper 
part of the Trapezius will elevate the point of the shoulder, as in supporting weights; 404 
MUSCLES AND FASCIAE. 
when the middle and lower fibres are brought into action, partial rotation of the 
scapula upon the side of the chest is produced. If the shoulders are fixed, both 
Trapezii, acting together, will draw the head directly backward, or if only one acts, 
the head is drawn to the corresponding side. [This muscle can be well shown on 
the living model by shrugging the shoulders, especially if the hands are weighted 
by dumb-bells, by clasping the hands behind the head, and so resisting extension 
of the head, and by drawing the two shoulders backward and crossing the arms 
behind the back.] 
The Latissimus dorsi, when it acts upon the humerus, draws it backward and 
downward, and at the same time rotates it inward. It is the muscle which is prin- 
cipally employed in giving a downward blow, as in felling a tree or in sabre practice. 
If the arm is fixed, the muscle may act in various ways upon the trunk ; thus, it 
may raise the lower ribs and assist in forcible inspiration, or if both arms are fixed 
the two muscles may assist the abdominal and great Pectoral muscles in suspending 
and drawing the whole trunk forward, as in climbing or walking on crutches. [Let 
the model hang by one arm from a ring or place his arm on your shoulder or other 
similar support and press downward, and the Latissimus will show finely.] 
The Levator anguli scapulce raises the superior angle of the scapula, assisting 
the Trapezius in bearing weights or in shrugging the shoulders, whilst the Rhomboid 
muscles carry the inferior angle backward and upward, thus producing a slight rota- 
tion of the scapula upon the side of the chest, the Rhomboideus major acting espe- 
cially on the lower angle of the scapula through the tendinous arch by which it is 
inserted. If the shoulder be fixed, the Levator anguli scapulae inclines the neck to 
the corresponding side and rotates it backward. The Rhomboid muscles, acting 
together with the middle and inferior fibres of the Trapezius, will draw the scapula 
directly backward toward the spine. [Clasping the hands behind the occiput and 
resisting the postero-lateral movement of the head, and shrugging the weighted 
shoulders as above, show the Levator anguli scapulae well. The Rhomboids are 
best seen when the model crosses the arms behind the back and then shrugs the 
shoulders.] 
Third Layer 
Serratus posticus superior. 
Serratus posticus inferior, 
Splenitis 
Splenius capitis. 
Splenius colli. 
Dissection.-To bring into view the third layer of muscles, remove the whole of the second, 
together with the Latissimus dorsi; by cutting through the Levator anguli scapulae and Rhom- 
boid muscles near their insertion, and reflecting them upward, to expose the Serratus posticus 
inferior, dividing the Latissimus dorsi in the middle by a vertical incision carried from its upper 
to its lower part, and reflecting the two halves of the muscle. 
The Serratus posticus superior is a thin, flat, quadrilateral muscle situated at 
the upper and back part of the thorax. It arises by a thin and broad aponeurosis 
from the ligamentum nuchae, and from the spinous processes of the last cervical and 
two or three upper dorsal vertebrae. Inclining downward and outward, it becomes 
muscular, and is inserted by four fleshy digitations into the upper borders of the 
second, third, fourth, and fifth ribs a little beyond their angles. 
Relations.-By its superficial surface with the Trapezius, Rhomboidei, and 
Levator anguli scapulae; by its deep surface with the Splenius, prolongations from 
the Erector spinae, Intercostal muscles, and ribs. 
The Serratus posticus inferior is situated at the junction of the dorsal and 
lumbar regions: it is of an irregularly quadrilateral form, broader than the preced- 
ing, and separated from it by a considerable interval. It arises by a thin aponeurosis 
from the spinous processes of the last two dorsal and two or three upper lumbar ver- 
tebrae, and from the interspinous ligaments. Passing obliquely upward and outward, 
it becomes fleshy and divides into four flat digitations, which are inserted into the 
lower borders of the four lower ribs a little beyond their angles. 
Relations.-By its superficial surface with the Latissimus dorsi, with the apo- MUSCLES OF THE BACK. 
405 
neurosis of which its own aponeurotic origin is inseparably blended; by its deep sur- 
face with the lumbar fascia, the Erector spinm, ribs, and Intercostal muscles. Its 
upper margin is continuous -with the vertebral aponeurosis. 
The Vertebral Fascia or Aponeurosis is a thin, fibrous lamina extending along 
the whole length of the back part of the thoracic region, serving to bind down the 
long extensor muscles of the back which support the spine and head, and separate 
them from those muscles which connect the spine to the upper extremity. It con- 
sists of longitudinal and transverse fibres blended together, forming a thin lamella, 
which is attached in the median line to the spinous processes of the dorsal vertebrae, 
externally to the angles of the ribs, and below to the upper border of the Inferior ser- 
ratus and tendon of origin of the Latissimus dorsi; above, it passes beneath the Ser- 
ratus posticus superior and the Splenius and blends with the deep fascia of the neck. 
Now detach the Serratus posticus superior from its origin and turn it outward, when the 
Splenius muscle will be brought into view. 
The Splenius is situated at the back of the neck and upper part of the dorsal 
region. At its origin it is a single muscle, narrow' and pointed in form, but it soon 
becomes broader and divides into two portions, which have separate insertions. It 
arises by tendinous fibres from the lower half of the ligamentum nuchae, from the 
spinous processes of the last cervical and of the six upper dorsal vertebrae, and 
from the supraspinous ligament. From this origin the fleshy fibres proceed 
obliquely upward and outward, forming a broad fiat muscle which divides as it 
ascends into two portions, the Splenius capitis and Splenius colli. 
The Splenius capitis is inserted into the mastoid process of the temporal bone, and 
into the rough surface on the occipital bone just beneath the superior curved line. 
The Splenius colli is inserted by tendinous fasciculi into the posterior tubercles 
of the transverse processes of the three or four upper cervical vertebras. 
The Splenius is separated from its fellow of the opposite side by a triangular 
interval, in which is seen the Complexus. 
Relations.-By its superficial surface with the Trapezius, from which it is 
separated below by the Rhomboidei and the Serratus posticus superior: it is cov- 
ered at its insertion by the Sterno-mastoid; by its deep) surface with the Spinalis 
dorsi, Longissimus dorsi, Semispinalis colli, Complexus, Trachelo-mastoid, and 
Transversalis colli. 
Nerves.-The Splenius and Superior serratus are supplied from the external 
branches of the posterior divisions of the cervical nerves; the Inferior serratus, 
from the external branches of the posterior divisions of the lower dorsal nerves. 
Actions.-The Serrati are respiratory muscles. The Serratus posticus superior 
elevates the ribs: it is therefore an inspiratory muscle ; while the Serratus inferior 
draws the lower ribs downward and backward, and thus elongates the thorax. It 
also fixes the low'er ribs, thus aiding the downward action of the diaphragm and 
resisting the tendency which it has to draw the lower ribs upward and forward. It 
must therefore be regarded as a muscle of inspiration, though by some anatomists 
it has been considered an expiratory muscle. This muscle is also probably a tensor 
of the vertebral aponeurosis. The Splenii muscles of the two sides, acting together, 
draw the head directly backward, assisting the Trapezius and Complexus; acting 
separately, they draw the head to one or the other side and slightly rotate it, turn- 
ing the face to the same side. They also assist in supporting the head in the erect 
position. 
Fourth Layer. 
Sacral and Lumbar Regions. 
Erector spinse. 
Dorsal Region. 
Sacro-lumbalis. 
Musculus accessorius acl sacro-lumbalem. 
Longissimus dorsi. 
Spinalis dorsi. 
Cervical Region. 
Cervicalis ascendens. 
Transversalis colli. 
Trachelo-mastoid. 
Complexus. 
Biventer cervicis. 
Spinalis colli. 406 
MUSCLES AND FASCIAE. 
Dissection.-To expose the muscles of the fourth layer remove entirely the Serrati and the 
vertebral and lumbar fasciae. Then detach the Splenius by separating its attachment to the 
spinous processes and reflecting it outward. 
The Erector spinae (Fig. 301) and its prolongations in the dorsal and cervical 
regions fill up the vertebral groove on each side of the spine. It is covered in the 
lumbar region by the lumbar fascia, in the dorsal region by the Serrati muscles and 
the vertebral fascia, and in the cervical region by a layer of cervical fascia con- 
tinued beneath the Trapezius. This large muscular and tendinous mass varies in 
size and structure at different parts of the spine. In the sacral region the Erector 
spinae is narrow and pointed, and its origin chiefly tendinous in structure. In the 
lumbar region the muscle becomes enlarged, and forms a large fleshy mass. In the 
dorsal region it subdivides into two parts, which gradually diminish in size as they 
ascend to be inserted into the vertebrae and ribs, and are gradually lost in the cer- 
vical region, where a number of special muscles are superadded: these are con- 
tinued upward to the head, and support it upon the spine. 
The Erector spinae arises from the sacro-iliac groove, and from the anterior sur- 
face of a very broad and thick tendon, which is attached internally to the spines of 
the sacrum, to the spinous processes of the lumbar and two or three lower dorsal 
vertebrae, and to the supraspinous ligament; externally to the back part of the inner 
lip of the crest of the ilium, and to the series of eminences on the posterior part 
of the sacrum which represent the transverse processes, where it blends with the 
great sacro-sciatic ligament. The muscular fibres form a single large fleshy mass, 
bounded in front by the transverse processes of the lumbar vertebrae, and by the 
middle lamella of the aponeurosis of origin of the Transversalis muscle. Oppo- 
site the last rib it divides into two parts, the Sacro-lumbalis and the Longissimus 
dorsi. 
The Sacro-lumbalis (Ilio-costalis), the external and smaller portion of the 
Erector spinae, is inserted by six or seven flattened tendons into the angles of the 
six or seven lower ribs. If this muscle is reflected outward, it will be seen to be 
reinforced by a series of muscular slips which arise from the angles of the ribs: by 
means of these the Sacro-lumbalis is continued upward to the upper ribs and the 
cervical portion of the spine. The accessory portions form two additional muscles, 
the Musculus accessorius and the Cervicalis ascendens. 
The Musculus accessorius ad sacro-lumbalem arises by separate flattened 
tendons from the angles of the six lower ribs; these become muscular, and are 
finally inserted by separate tendons into the angles of the six upper ribs. 
The Cervicalis ascendens1 is the continuation of the Accessorius upward into 
the neck ; it is situated on the inner side of the tendons of the Accessorius, arising 
from the angles of the four or five upper ribs, and is inserted by a series of slender 
tendons into the posterior tubercles of the transverse processes of the fourth, fifth, 
and sixth cervical vertebrae. 
The Longissimus dorsi, the inner and larger portion of the Erector spinae, 
arises, with the Sacro-lumbalis, from the common origin above described. In the 
lumbar region, where it is as yet blended with the Sacro-lumbalis, some of the 
fibres are attached to the whole length of the posterior surface of the transverse 
processes of the lumbar vertebrae, to the tubercles at the back of the articular pro- 
cesses, and to the middle layer of the aponeurosis of origin of the Transversalis 
abdominis muscle. In the dorsal region the Longissimus dorsi is inserted by long 
thin tendons into the tips of the transverse processes of all the dorsal vertebrae, and 
into from seven to eleven of the lower ribs between their tubercles and angles. 
This muscle is continued upward to the cranium and cervical portion of the 
spine by means of two additional muscles, the Transversalis colli and Trachelo- 
mastoid. 
The Transversalis colli (or cervicis), placed on the inner side of the Longis- 
1 This muscle is sometimes called " Cervicalis descendens." The student should remember that 
these long muscles take their fixed point from above or from below, according to circumstances. MUSCLES OF THE BACK. 
407 
Fig. 301. 
MVLTIFIDUS SPIN/t- 
fst Dorsal Vr 
-jtfRib 
.2& 
V? 
$ SacraWv 
Muscles of the Back, deep layers. 408 
MUSCLES AND FASCIAE. 
simus dorsi, arises by long thin tendons from the summits of the transverse pro- 
cesses of the six upper dorsal vertebrae, and is inserted by similar tendons into 
the posterior tubercles of the transverse processes of the cervical from the second 
to the sixth. 
The Trachelo-mastoid. lies on the inner side of the preceding, between it and 
the Complexus muscle. It arises by four tendons from the transverse processes of 
the third, fourth, fifth, and sixth dorsal vertebrae, and by additional separate ten- 
dons from the articular processes of the three or four lower cervical. The fibres 
form a small muscle which ascends to be inserted into the posterior margin of the 
mastoid process, beneath the Splenius and Sterno-mastoid muscles. This small 
muscle is almost always crossed by a tendinous intersection near its insertion into 
the mastoid process. 
The Spinalis dorsi connects the spinous processes of the upper lumbar and the 
dorsal vertebrae together by a series of muscular and tendinous slips which are inti- 
mately blended with the Longissimus dorsi. It is situated at the inner side of the 
Longissimus dorsi, arising by three or four tendons from the spinous processes of 
the first two lumbar and the last two dorsal vertebrae: these, uniting, form a small 
muscle which is inserted by separate tendons into the spinous processes of the dorsal 
vertebrae, the number varying from four to eight. It is intimately united with the 
Semispinalis dorsi, which lies beneath it. 
The Spinalis colli is a small muscle connecting together the spinous processes 
of the cervical vertebrae, and analogous to the Spinalis dorsi in the dorsal region. 
It varies considerably in its size and in its extent of attachment to the vertebrae, 
not only in different bodies, but on the two sides of the same body. It usually 
arises by fleshy or tendinous slips, varying from two to four in number, from the 
spinous processes of the fifth, sixth, and seventh cervical vertebrae, and occasionally 
from the first and second dorsal, and is inserted into the spinous process of the axis, 
and occasionally into the spinous processes of the two vertebrae below it. This mus- 
cle was found absent in five cases out of twenty-four. 
The Complexus is a broad, thick muscle situated at the upper and back part of 
the neck, beneath the Splenius and internal to the Transversalis colli and Trachelo- 
mastoid. It arises by a series of tendons, about seven in number, from the tips of 
the transverse processes of the uppei* three dorsal and seventh cervical, and from 
the articular processes of the three cervical above this. The tendons uniting form 
a broad muscle which passes obliquely upward and inward, and is inserted into the 
innermost depression between the two curved lines of the occipital bone. This muscle 
about its middle is traversed by a transverse tendinous intersection. 
The Biventer cervicis is a small fasciculus situated on the inner side of the pre- 
ceding, and in the majority of cases blended with it; it has received its name from 
having a tendon intervening between two fleshy bellies. It is sometimes described 
as a separate muscle, arising by from two to four tendinous slips from the transverse 
processes of as many of the upper dorsal vertebrse, and inserted on the inner side of 
the Complexus into the superior curved line of the occipital bone. 
Relations.-The muscles of the fourth layer are bound down to the vertebrae 
and ribs in the dorsal and lumbar regions by the lumbar and vertebral fasciae. The 
inner part covers the muscles of the fifth layer. In the neck they are in relation by 
their superficial surface with the Trapezius and Splenius-by their deep surface 
with the Semispinalis dorsi and colli and the Recti and Obliqui. The Biventer 
cervicis is separated from its fellow of the opposite side by the ligamentum nuchae, 
and the Complexus from the Semispinalis colli by the profunda cervicis artery, the 
princeps cervicis artery, and branches of the posterior cervical plexus of nerves. 
Nerves.-The Erector spinae and its subdivisions in the dorsal region are sup- 
plied by the external branches of the posterior divisions of the lumbar and dorsal 
nerves; the Cervicalis ascendens, Transversalis colli, Trachelo-mastoid, and Spinalis 
colli, by the external branches of the posterior divisions of the cervical nerves; 
the Complexus, by the internal branches of the posterior divisions of the cervical 
nerves, the suboccipital, and great occipital. MUSCLES OF THE BACK. 
409 
Fifth Layer. 
Semispinalis dorsi. 
Semispinalis colli. 
Multifidus spinae. 
Rotatores spinae. 
Supraspinales. 
Interspinales. 
Extensor coccygis. 
Intertransversales. 
Rectus capitis posticus major. 
Rectus capitis posticus minor. 
Obliquus capitis superior. 
Obliquus capitis inferior. 
Dissection.-Remove the muscles of the preceding layer by dividing and turning aside the 
Complexus, then detaching the Spinalis and Longissimus dorsi from their attachments, dividing 
the Erector spinae at its connection below to the sacral and lumbar spines and turning it out- 
ward. The muscles filling up the interval between the spinous and transverse processes are 
then exposed. 
The Semispinales muscles (Fig. 301) connect the transverse and articular pro- 
cesses to the spinous processes of the vertebrae, extending from the lower part of 
the dorsal region to the upper part of the cervical. 
The Semispinalis dorsi consists of thin, narrow, fleshy fasciculi interposed 
between tendons of considerable length. It arises by a series of small tendons 
from the transverse processes of the lower dorsal vertebrae, from the tenth or 
eleventh to the fifth or sixth, and is inserted by five or six tendons into the spinous 
processes of the upper four dorsal and lower two cervical vertebrae. 
The Semispinalis colli, thicker than the preceding, arises by a series of tendin- 
ous and fleshy points from the transverse processes of the upper four dorsal vertebrae 
and from the articular processes of the lower four cervical vertebrae, and is inserted 
into the spinous processes of four cervical vertebrae from the axis to the fifth cer- 
vical. The fasciculus connected with the axis is the largest, and chiefly muscular in 
structure. 
Relations.-By their superficial surface from below upward with the Longis- 
simus dorsi, Spinalis dorsi, Splenius, Complexus, the profunda cervicis artery, the 
princeps cervicis artery, and the internal branches of the posterior divisions of the 
first, second, and third cervical nerves; by their deep surface with the Multifidus 
spinae. 
The Multifidus spinae consists of a number of fleshy and tendinous fasciculi 
which fill up the groove on either side of the spinous processes of the vertebrae 
from the sacrum to the axis. In the sacral region these fasciculi arise from the 
back of the sacrum as low as the fourth sacral foramen, and from the aponeurosis 
of origin of the Erector spinae; in the iliac region, from the inner surface of the 
posterior superior spine of the ilium and posterior sacro-iliac ligaments; in the 
lumbar and cervical regions, from the articular processes; and in the dorsal region, 
from the transverse processes. Each fasciculus, ascending obliquely upward and 
inward, is inserted into the lamina and whole length of the spinous process of one 
of the vertebrae above. These fasciculi vary in length : the most superficial, the 
longest, pass from one vertebra to the third or fourth above; those next in order 
pass from one vertebra to the second or third above ; whilst the deepest connect two 
contiguous vertebrae. 
Relations.-By its superficial surface with the Longissimus dorsi, Spinalis 
dorsi, Semispinalis dorsi, and Semispinalis colli; by its deep surface with the lam- 
inae and spinous processes of the vertebrae and with the Rotatores spinae in the 
dorsal region. 
The Rotatores spinae are found only in the dorsal region of the spine, beneath 
the Multifidus spinae; they are eleven in number on each side. Each muscle 
is small and somewhat quadrilateral in form; it arises from the upper and back 
part of the transverse process, and is inserted into the lower border and outer 
surface of the lamina of the vertebra above, the fibres extending as far inward as 
the root of the spinous process. The first is found between the first and second 
dorsal; the last, between the eleventh and twelfth. Sometimes the number of these 
muscles is diminished by the absence of one or more from the upper or lower end. MUSCLES AND FASCIAE. 
410 
The Supraspinales consist of a series of fleshy bands which lie on the spinous 
processes in the cervical region of the spine. 
The Interspinales are short muscular fasciculi placed in pairs between the spin- 
ous processes of the contiguous vertebras. In the cervical region they are most dis- 
tinct, and consist of six pairs, the first being situated between the axis and third 
Vertebra, and the last between the last cervical and the first dorsal. They are small 
narrow bundles, attached above and below to the apices of the spinous processes. 
In the dorsal region they are found between the first and second vertebrae, and 
occasionally between the second and third, and below between the eleventh and 
twelfth. In the lumbar region there are four pairs of these muscles in the intervals 
between the five lumbar vertebrae. There is also occasionally one in the interspin- 
ous space between the last dorsal and first lumbar and between the fifth lumbar 
and the sacrum. 
The Extensor coccygis is a slender muscular fasciculus occasionally present 
which extends over the lower part of the posterior surface of the sacrum and coccyx. 
It arises by tendinous fibres from the last bone of the sacrum or first piece of the 
coccyx, and passes downward to be inserted into the lower part of the coccyx. It 
is a rudiment of the Extensor muscle of the caudal vertebrae which exists in some 
animals. 
The Intertransversales are small muscles placed between the transverse pro- 
cesses of the vertebrae. In the cervical region they are most developed, consisting 
of two rounded muscular and tendinous fasciculi which pass between the anterior 
and posterior tubercles of the transverse processes of two contiguous vertebrae, 
separated from one another by the anterior branch of a cervical nerve, which 
lies in the groove between them, and by the vertebral artery and vein. In this 
region there are seven pairs of these muscles, the first being between the atlas 
and axis, and the last between the seventh cervical and first dorsal vertebrae. In 
the dorsal region they are least developed, consisting chiefly of rounded tendinous 
cords in the intertransverse spaces of the upper dorsal vertebrae; but between the 
transverse processes of the lower three dorsal vertebrae and the first lumbar they 
are muscular in structure. In the lumbar region they are foui' in number, and 
consist of a single muscular layer which occupies the entire interspace between the 
transverse processes of the lower lumbar vertebras, whilst those between the trans- 
verse processes of the upper lumbar are not attached to more than half the breadth 
of the process. 
The Rectus capitis posticus major arises by a pointed tendinous origin from 
the spinous process of the axis, and, becoming broader as it ascends, is inserted 
into the inferior curved line of the occipital bone and the surface of bone imme- 
diately below it. As the muscles of the two sides ascend upward and outward, they 
leave between them a triangular space in which are seen the Recti capitis postici 
minores muscles. 
Relations.-By its superficial surface with the Complexus, and at its insertion 
with the Superior oblique; by its deep surface with the posterior arch of the atlas, 
the posterior occipito-atloid ligament, and part of the occipital bone. 
The Rectus capitis posticus minor, the smallest of the four muscles in this 
region, is of a triangular shape: it arises by a narrow pointed tendon from the 
tubercle on the posterior arch of the atlas, and, becoming broader as it ascends, is 
inserted into the rough surface beneath the inferior curved line nearly as far as the 
foramen magnum, nearer to the middle line than the preceding. 
Relations.-By its superficial surface with the Complexus and Rectus capitis 
posticus major; by its deep surface with the posterior occipito-atloid ligament. 
The Obliquus capitis inferior, the larger of the two Oblique muscles, arises 
from the apex of the spinous process of the axis, and passes almost horizontally out- 
ward to be inserted into the lower and back part of the transverse process of the atlas. 
Relations.-By its superficial surface with the Complexus, and with the poste- 
rior branch of the second cervical nerve which crosses it; by its deep surface with 
the vertebral artery and posterior atlo-axoid ligament. MUSCLES OF THE ABDOMEN. 
411 
The Obliquus capitis superior, narrow below, wide and expanded above, arises 
by tendinous fibres from the upper surface of the transverse process of the atlas, 
joining with the insertion of the preceding, and, passing obliquely upward and 
inward, is inserted into the occipital bone between the two curved lines external to 
the Complexus. Between the two oblique muscles and the Rectus posticus major a 
triangular interval [the suboccipital triangle], exists in which are seen the vertebral 
artery and the posterior branch of the suboccipital nerve. 
Relations.-By its superficial surface with the Complexus and Trachelo-mas- 
ioid; by its deep surface with the posterior occipito-atloid ligament. 
Nerves.-The Semispinalis dorsi and Rotatores spinae are supplied by the inter- 
nal branches of the posterior divisions of the dorsal nerves; the Semispinalis colli, 
Supraspinales, and Interspinales, by the internal branches of the posterior divisions 
of the cervical nerves; the Intertransversales, by the internal branches of the pos- 
terior divisions of the cervical, dorsal, and lumbar nerves; the Multifidus spinae, by 
the same, with the addition of the internal branches of the posterior divisions of the 
sacral nerves. The Recti and Obliqui muscles are all supplied by the suboccipital 
nerve; the Inferior oblique is also supplied by the great occipital nerve. 
Actions.-The Erector spinae, comprising the Sacro-lumbalis with its accessory 
muscles, the Longissimus dorsi, and Spinalis dorsi, serves, as its name implies, to 
maintain the spine in the erect posture; it also serves to bend the trunk backward 
when it is required to counterbalance the influence of any weight at the front of 
the body; as, for instance, when a heavy weight is suspended from the neck or 
when there is any great abdominal development, as in pregnancy or dropsy: the 
peculiar gait under such circumstances depends upon the spine being drawn back- 
ward by the counterbalancing action of the Erector spinae muscles. [Let the model 
bend forward and slowly lift a heavy weight from the floor. Watch the Erector 
spinae mass spring into marked rounded relief until he is entirely erect and bal- 
anced, when it quickly subsides.] The muscles which form the continuation of the 
Erector spinae upward steady the head and neck and fix them in the upright posi- 
tion. If the Sacro-lumbalis and Longissimus dorsi of one side act, they serve to 
draw down the chest and spine to the corresponding side. The Cervicalis ascen- 
dens, taking its fixed point from the cervical vertebrae, elevates those ribs to which 
it is attached. The Multifidus spinae acts successively upon the different parts of 
the spine; thus, the sacrum furnishes a fixed point from which the fasciculi of this 
muscle act upon the lumbar region; these then become the fixed points for the fas- 
ciculi moving the dorsal region, and so on throughout the entire length of the spine; 
it is by the successive contraction and relaxation of the separate fasciculi of this and 
other muscles that the spine preserves the erect posture without the fatigue that 
would necessarily have been produced had this position been maintained by the 
action of a single muscle. The Multifidus spime, besides preserving the erect posi- 
tion of the spine, serves to rotate it, so that the front of the trunk is turned to the 
side opposite to that from which the muscle acts, this muscle being assisted in its 
action by the Obliquus externus abdominis. The Complexi, the analogues of the 
Multifidus spinae in the neck, draw the head directly backward; if one muscle acts, 
it draws the head to one side and rotates it so that the face is turned to the opposite 
side. The Rectus capitis posticus minor and the Superior oblique draw the head 
backward; and the latter, from the obliquity in the direction of its fibres, may 
turn the face to the opposite side. The Rectus capitis posticus major and the 
Obliquus inferior rotate the atlas, and with it the cranium, round the odontoid 
process, and turn the face to the same side. 
The muscles in this region are the 
Muscles of the Abdomen. 
Obliquus externus. 
Obliquus internus. 
Transversalis. 
Rectus. 
Pyramidalis. 
Quadratus lumborum. 412 
MUSCLES AND FASCIAE. 
Dissection (Fig. 302).-To dissect the abdominal muscles make a vertical incision from the 
ensiform cartilage to the pubes, a second incision from the umbilicus obliquely upward and out- 
ward to the outer surface of the chest, as high as the lower border of the fifth or sixth rib, and 
a third, commencing midway between the umbilicus and pubes, transversely outward to the 
anterior superior iliac spine and along the crest of the ilium as far as its posterior third. Then 
reflect the three flaps included between these incisions from within outward in the lines of direc- 
tion of the muscular fibres. If necessary, the abdominal muscles may be made tense by inflat- 
ing the peritoneal cavity through the umbilicus. 
The Superficial Fascia of the abdomen consists over the greater part of the 
abdominal wall of a single layer of fascia, which contains a variable amount of fat; 
but as this layer approaches the groin it is easily divisible into two layers, of which 
the superficial one is fatty, and is continuous with 
the subcutaneous fat in the upper part of the ab- 
domen and in the thigh: the deeper layer is thin- 
ner and more membranous in character, and is 
separated from the superficial one by the subcuta- 
neous vessels. Above it is continuous with the 
superficial fascia over the rest of the trunk, but 
below it blends with the fascia lata of the thigh 
a little below Poupart's ligament, and below and 
internally it is continued to the penis and scro- 
tum, where it becomes very thin and reaches the 
perineum. This fascia will be described more 
particularly in connection with the subject of the 
surgical anatomy of inguinal hernia, to which the 
student is referred. 
The [Obliquus externus abdominis] Ex- 
ternal or Descending- Oblique Muscle (Fig. 
303) is situated on the side and fore part of the 
abdomen, being the largest and the most super- 
ficial of the three flat muscles in this region. It is 
broad, thin, and irregularly quadrilateral, its mus- 
cular portion occupying the side, its aponeurosis 
the anterior wall of the abdomen. It arises by 
eight fleshy digitations from the external surface 
and lower borders of the eight inferior ribs; these 
digitations are arranged in an oblique line running downward and backward, the 
upper ones being attached close to the cartilages of the corresponding ribs; the 
lowest to the apex of the cartilage of the last rib ; the intermediate ones to the ribs 
at some distance from their cartilages. The five superior serrations increase in size 
from above downward, and are received between corresponding processes of the Ser- 
ratus magnus: the three lower ones diminish in size from above downward, receiv- 
ing between them corresponding processes from the Latissimus dorsi. From these 
attachments the fleshy fibres proceed in various directions. Those from the lowest 
ribs pass nearly vertically downward, to be inserted into the anterior half of the 
outer lip of the crest of the ilium; the middle and upper fibres, directed downward 
and forward, terminate in tendinous fibres, which spread out into a broad aponeur- 
osis. This aponeurosis, joined with that of the opposite muscle along the median 
line, covers the whole of the front of the abdomen; above, it is connected with 
the lower border of the Pectoralis major; below, its fibres are closely aggregated 
together, and extend obliquely across from the anterior superior spine of the ilium 
to the spine of the os pubis and the linea ilio-pectinea. In the median line it 
interlaces with the aponeurosis of the opposite muscle, forming the linea alba, 
and extends from the ensiform cartilage to the symphysis pubis. 
That portion of the aponeurosis which extends between the anterior superior 
spine of the ilium and the spine of the os pubis is a broad, stout band folded inward, 
and continuous below with the fascia lata; it is called Poupart's ligament [and 
is one of the most important landmarks of the abdomen and thigh]. The portion 
Fig. 302. 
3. I 
Di/sseetioik 
INGUINAL 
HERNIA 
Dissection of Abdomen. MUSCLES OF THE ABDOMEN. 
413 
which is reflected from Poupart's ligament on to the pectineal line is called Grimber- 
nat's ligament.1 From the point of attachment of the latter to the pectineal line a 
few fibres pass upward and inward, behind the inner pillar of the ring, to the linea 
alba. They diverge as they ascend, and form a thin, triangular, fibrous band which 
is called the triangular ligament. 
In the aponeurosis of the External oblique, immediately above the crest of the 
os pubis, is a triangular opening, the external abdominal ring, formed by a separa- 
Fig. 303. 
Ext. Abdominal Ring- 
Giinbemai's Lig't.- 
The External Oblique Muscle. 
tion of the fibres of the aponeurosis in this situation : it serves for the transmission 
of the spermatic cord in the male and the round ligament in the female. This open- 
ing is directed obliquely upward and outward, and corresponds with the course of 
the fibres of the aponeurosis. It is bounded below by the crest of the os pubis; 
above by some curved fibres, which pass across the aponeurosis at the upper angle 
1 All these parts will be found more particularly described hereafter, with the Surgical Anatomy 
of Hernia. MUSCLES AND FASCIAE. 
414 
of the ring so as to increase its strength; and on either side by the margins of the 
aponeurosis, which are called the pillars [or columns] of the ring. Of these, the 
external-which is at the same time inferior, from the obliquity of its direction-is 
inserted into the spine of the os pubis. The internal or superior pillar is attached 
to the front of the pubes and symphysis pubis, and interlaces with the correspond- 
ing fibres of the opposite muscle, the fibres of the right muscle being superficial. 
To the margins of the pillars of the external abdominal ring is attached an exceed- 
ingly thin and delicate fascia, which is prolonged down over the outer surface of 
the cord and testis. This has received the name of intercolumnar fascia, from its 
attachment to the pillars of the ring. It is also called the external spermatic fascia, 
from being the most external of the fasciae which cover the spermatic cord. 
Relations.-By its external surface with the superficial fascia, superficial epi- 
gastric and circumflex iliac vessels, and some cutaneous nerves. By its internal 
surface with the Internal oblique, the lower part of the eight inferior ribs and Inter- 
costal muscles, the cremaster, the spermatic cord in the male and the round ligament 
in the female. Its posterior border is occasionally overlapped by the Latissimus 
dorsi; generally an interval exists between the two muscles in which is seen a por- 
tion of the Internal oblique. 
Dissection.-Detach the External oblique by dividing it across, just in front of its attachment 
to the ribs, as far as its posterior border, and separating it below from the crest of the ilium as 
far as the spine; then separate the muscle carefully from the Internal oblique, which lies beneath, 
and turn it toward the opposite side. 
The [Obliquus interims abdominis] Internal or Ascending Oblique Muscle 
(Fig. 304), thinner and smaller than the preceding, beneath which it lies, is of an 
irregularly quadrilateral form and situated at the side and fore part of the abdomen. 
It arises by fleshy fibres from the outer half of Poupart's ligament, being attached 
to the groove on its upper surface, from the anterior two-thirds of the middle lip of 
the crest of the ilium, and from the posterior lamella of the lumbar fascia. From 
this origin the fibres diverge: those from Poupart's ligament, few in number and 
paler in color than the rest, arch downward and inward across the spermatic cord, 
to be inserted, conjointly with those of the Transversalis, into the crest of the os 
pubis and pectineal line to the extent of half an inch, forming what is known as the 
conjoined tendon of the Internal oblique and Transversalis ; those from the anterior 
superior iliac spine are horizontal in their direction ; whilst those which arise from 
the fore part of the crest of the ilium pass obliquely upward and inward, and ter- 
minate in an aponeurosis which is continued forward to the linea alba; the most 
posterior fibres pass almost vertically upward, to be inserted into the lower borders 
of the cartilages of the four lower ribs, being continuous with the Internal inter- 
costal muscles. 
The conjoined tendon of the Internal oblique and Transversalis is inserted into 
the crest of the os pubis and pectineal line, immediately behind the external abdom- 
inal ring, serving to protect what would otherwise be a weak point in the abdominal 
wall. Sometimes this tendon is insufficient to resist the pressure from within, and 
is carried forward in front of the protrusion through the external ring, forming one 
of the coverings of direct inguinal hernia. 
The aponeurosis of the Internal oblique is continued forward to the middle line 
of the abdomen, where it joins with the aponeurosis of the opposite muscle at the 
linea alba and extends from the margin of the thorax to the pubes. At the outer 
margin of the Rectus muscle this aponeurosis, for the upper three-fourths of its 
extent, divides into two lamellae, which pass, one in front and the other behind the 
muscle, enclosing it in a kind of sheath, and reuniting on its inner border at the 
linea alba; the anterior layer is blended with the aponeurosis of the External oblique 
muscle, the posterior layer with that of the Transversalis. Along the lower fourth 
the aponeurosis passes altogether in front of the Rectus without any separation. 
Relations.-By its external surface with the External oblique, Latissimus dorsi, 
spermatic cord, and external ring; by its internal surface with the Transversalis mus- MUSCLES OF THE ABDOMEN. 
415 
Fig. 304. 
Cenjoined Tendon 
CREMA5TER- 
Pu l> Pi' 
The Internal Oblique Muscle, 
cle, fascia transversal is, internal ring, and spermatic cord. Its lower border forms the 
upper boundary of the spermatic canal. 
Dissection.-Detach the Internal oblique in order to expose the Transversalis beneath. This 
may be effected by dividing the muscle above at its attachment to the ribs; below at its connec- 
tion with Poupart's ligament and the crest of the ilium; and behind by a vertical incision 
extending from the last rib to the crest of the ilium. The muscle should previously be made 
tense by drawing upon it with the fingers of the left hand, and if its division is carefully effected 
the cellular interval between it and the Transversalis, as well as the direction of the fibres of 
the latter muscle, will afford a clear guide to their separation: along the crest of the ilium the 
circumflex iliac vessels are interposed between them, and form an important guide in separating 
them. The muscle should then be thrown forward toward the linea alba. 
The Transversalis Muscle (Fig. 305), so called from the direction of its fibres, 
is the most internal flat muscle of the abdomen, being placed immediately beneath 
the Internal oblique. It arises by fleshy fibres from the outer third of Poupart's 
ligament, from the inner lip of the crest of the ilium, its anterior three-fourths, 
from the inner surface of the cartilages of the six lower ribs, interdigitating with 
the Diaphragm, and by a broad aponeurosis from the spinous and transverse pro- 
cesses of the lumbar vertebrae. The muscle terminates in front in a broad apo- 
neurosis, the lower fibres of which curve downward, and are inserted, together with 
those of the internal oblique, into the crest of the os pubis and pectineal line, form- 
ing what was described above as the conjoined tendon of these muscles. Through- 
out the rest of its extent the aponeurosis passes horizontally inward, and is inserted 
into the linea alba; its upper three-fourths, passing behind the Rectus muscle, 416 
MUSCLES AND FASCIAE. 
blending with the posterior lamella of the Internal oblique; its lower fourth pass- 
ing in front of the Rectus. 
Relations.-By its external surface with the Internal oblique, the inner sur- 
face of the lower ribs, and Internal intercostal muscles. Its inner surface is lined 
by the fascia transversalis, which separates it from the peritoneum. Its lower 
border forms the upper boundary of the spermatic canal. 
Fig. 305. 
Li'ttt al I a - 
The Transversalis, Rectus, and Pyramidalis Muscles. 
Lumbar Fascia (Fig. 306).-The vertebral or posterior aponeurosis of the 
Transversalis, sometimes called the lumbar fascia, divides into three layers: an 
anterior, very thin, which is attached to the front part of the transverse processes 
of the lumbar vertebrae, and above to the lower margin of the last rib, where it 
forms the ligamentuni arcuatum externum; a middle layer, much stronger, which 
is attached to the apices of the transverse processes; and a posterior layer, attached MUSCLES OF THE ABDOMEN. 
417 
to the apices of the spinous processes. Between the anterior and middle layer is 
situated the Quadratus lumborum; between the middle and posterior, the Erector 
spinse and Multifidus spinse. The posterior lamella of this aponeurosis gives 
Fig. 306. 
A Transverse Section of the Abdomen in the Lumbai;Region. 
attachment to the Internal oblique; it is also blended with the aponeurosis of the 
Serratus posticus inferior and with that of the Latissimus dorsi, forming the lumbar 
fascia. 
Dissection.-To expose the Rectus muscle, open its sheath by a vertical incision extending 
from the margin of the thorax to the pubes, and then reflect the two portions from the surface 
of the muscle; which is easily done, excepting at the linese transversse, where so close an adhe- 
sion exists that the greatest care is requisite in separating them. Now raise the outer edge of 
the muscle in order to examine the posterior layer of the sheath. By dividing the muscle in 
the centre, and turning its lower part downward, the point where the posterior wall of the 
sheath terminates in a thin curved margin will be seen. 
The Rectus abdominis is a long flat muscle which extends along the whole 
length of the front of the abdomen, being separated from its fellow of the opposite 
side by the linea alba. It is much broader above than below, and arises by two 
tendons, the external or larger being attached to the crest of the os pubis, the 
internal, smaller portion interlacing with its fellow of the opposite side and being 
connected with the ligaments covering the symphysis pubis. The fibres ascend 
vertically, and the muscle, becoming broader and thinner at its upper part, is 
inserted by three portions of unequal size into the cartilages of the fifth, sixth, 
and seventh ribs. Some fibres are occasionally connected with the costo-xiphoid 
ligaments and side of the ensiform cartilage. 
The Rectus muscle is traversed by a series of tendinous intersections which vary 
from two to five in number, and have received the name of Linece transverse?. One 
of these is usually situated opposite the umbilicus, and two above that point; of the 
latter, one corresponds to the extremity of the ensiform cartilage, and the other to 
the interval between the ensiform cartilage and the umbilicus; there is occasionally 
one below the umbilicus. These intersections pass, transversely or obliquely across 
the muscle in a zigzag course; they rarely extend completely through its substance, 
sometimes pass only halfway across it, and are intimately adherent to the sheath in 
which the muscle is enclosed. 
The Rectus is enclosed in a sheath (Fig. 306) formed by the aponeuroses of the 
Obliciue and Transversalis muscles, which are arranged in the following manner: 
When the aponeurosis of the Internal oblique arrives at the outer margin of the 
Rectus, it divides into two lamellae, one of which passes in front of the Rectus, 418 
MUSCLES AND FASCIAE. 
blending with the aponeurosis of the External oblique, the other, behind it, blend- 
ing with the aponeurosis of the Transversalis; and these, joining again at its 
inner border, are inserted into the linea alba. This arrangement of the fasciae 
exists along the upper three-fourths of the muscle: at the commencement of the 
lower fourth the posterior wall of the sheath terminates in a thin curved margin, 
the semilunar fold of Douglas, the concavity of which looks downward toward the 
pubes, the aponeuroses of all three muscles passing in front of the Rectus without 
any separation. The Rectus muscle, in the situation where its sheath is deficient, 
is separated from the peritoneum by the transversalis fascia. 
The Pyramidalis is a small muscle, triangular in shape, placed at the lower 
part of the abdomen in front of the Rectus, and contained in the same sheath with 
that muscle. It arises by tendinous fibres from the front of the os pubis and the 
anterior pubic ligament; the fleshy portion of the muscle passes upward, diminish- 
ing in size as it ascends, and terminates by a pointed extremity, which is inserted 
into the linea alba midway between the umbilicus and the os pubis. This muscle is 
sometimes found wanting on one or both sides ; the lower end of the Rectus then 
becomes proportionately increased in size. Occasionally it has been found double 
on one side, or the muscles of the two sides are of unequal size. Sometimes its 
length exceeds what is stated above. 
The Quadratus lumborum (Fig- 301, p. 407) is situated in the lumbar region; 
it is irregularly quadrilateral in shape, broader below than above, and consists of two 
portions. One portion arises by aponeurotic fibres from the ilio-lumbar ligament and 
the adjacent portion of the crest of the ilium for about two inches, and is inserted 
into the lower border of the last rib about half its length, and by four small ten- 
dons into the apices of the transverse processes of the four upper lumbar vertebrae. 
The other portion of the muscle, situated in front of the preceding, arises from the 
upper border of the transverse processes of the third, fourth, and fifth lumbar ver- 
tebrae, and is inserted into the lower margin of the last rib. This portion is not 
always found. The Quadratus lumborum is contained in a sheath formed by the 
anterior and middle lamellae of the aponeurosis of origin of the Transversalis. 
Relations.-Its anterior surface (or rather the fascia which covers its anterior 
surface) is in relation with the colon, the kidney, the psoas muscle, and the dia- 
phragm. Its posterior surface is in relation with the middle lamella of the lum- 
bar fascia, which separates it from the Erector spinae. The Quadratus lumborum 
extends, however, beyond the outer border of the Erector spinae. [The relations 
of the Quadratus should be carefully studied, in view of the now frequent opera- 
tions in this region on the colon and the kidney.] 
Nerves.-The abdominal muscles are supplied by the lower intercostal, ilio- 
hypogastric, and ilio-inguinal nerves. The Quadratus lumborum receives filaments 
from the anterior branches of the lumbar nerves. 
In the description of the abdominal muscles mention has frequently been made 
of the linea alba, lineae semilunares, and lineae transversae: when the dissection of 
the muscles is completed these structures should be examined. 
The Linea alba is a tendinous raphe or cord seen along the middle line of the 
abdomen, extending from the ensiform cartilage to the pubes. It is placed between 
the inner borders of the Recti muscles, and is formed by the blending of the apo- 
neuroses of the Oblique and Transversalis muscles. It is narrow below, corre- 
sponding to the narrow interval existing between the Recti, but broader above, as 
these muscles diverge from one another in their ascent, becoming of considerable 
breadth after great distension of the abdomen from pregnancy or ascites. It pre- 
sents numerous apertures for the passage of vessels and nerves; the largest of these 
is the Umbilicus, which in the foetus transmits the umbilical vessels, but in the 
adult is obliterated, the cicatrix being stronger than the neighboring parts; hence 
umbilical hernia occurs in the adult near the umbilicus, whilst in the foetus it occurs 
at the umbilicus. [The difference in the umbilicus in the two sexes is marked : in 
men it is small and narrow, in women wide and deep, irrespective of pregnancy. 
The best antique statues make the distinction accurately. At the umbilicus all the MUSCLES AND FASCIAE OF THE THORAX. 
419 
structures of the belly-wall are united. Hence when in laparotomy any doubt exists 
as to whether the peritoneal cavity has been opened, try to sweep the finger under 
the umbilicus. If it passes freely under it (after breaking up any adhesions that 
may exist), the belly-cavity is opened; if not, the finger is between two layers of 
the belly-wall.] The linea alba is in relation in front with the integument, to which 
it is adherent, especially at the umbilicus; behind, it is separated from the perito- 
neum by the transversalis fascia; and below, by the urachus and the bladder when 
that organ is distended. 
The Linese semilunares are two curved tendinous lines placed one on each side 
of the linea alba. Each corresponds with the outer border of the Rectus muscle, 
extends from the cartilage of the eighth rib to the pubes, and is formed by the apo- 
neurosis of the internal oblique at its point of division to enclose the Rectus, where 
it is reinforced in front and behind by the External oblique and Transversalis. 
The Linese transversse are three or four narrow transverse lines which intersect 
the Rectus muscle, as already mentioned; they connect the lineae semilunares with 
the linea alba. 
Actions.-The abdominal muscles perform a threefold action : 
When the pelvis and thorax are fixed they compress the abdominal viscera by 
constricting the cavity of the abdomen, in which action they are materially assisted 
by the descent of the diaphragm. By these means [in part] the foetus is expelled 
from the uterus, the feces from the rectum, the urine from the bladder, and the con- 
tents of the stomach in vomiting. 
If the pelvis and spine are fixed, these muscles compress the lower part of the 
thorax [and push up the diaphragm by compressing the viscera], materially assist- 
ing expiration. If the pelvis alone is fixed, the thorax is bent directly forward 
when the muscles of both sides act, or to either side when those of one side act alone, 
rotation of the trunk at the same time taking place toward the opposite side. 
If the thorax is fixed, these muscles, acting together, draw the pelvis [forward 
and] upward, as in climbing; or, acting singly, they draw the pelvis upward and 
rotate the vertebral column to one side or the other. The Recti muscles, acting 
from below, depress the thorax, and consequently flex the vertebral column; when 
acting from above, they flex the pelvis upon the vertebral column. The Pyramidales 
are tensors of the linea alba. 
The Quadratus lumborum by the portion inserted into the last rib draws down 
and fixes that bone, acting thereby as a muscle of forced expiration, but at the same 
time, by fixing the last rib, it opposes the tendency of the diaphragm to draw it 
upward, and thus it becomes an assistant to inspiration: by the portion inserted 
into the lumbar vertebrae it draws the spine toward the ilium, and thus inclines the 
trunk toward its own side; or, if the thorax and spine be fixed, it may act upon the 
pelvis, raising it toward its own side when only one muscle is put in action; and 
when both muscles act together, either from below or above, they flex the trunk. 
[Several different actions will show these muscles well in the model. Folding the 
arms behind the back or placing them akimbo, and then bending backward, show 
the External oblique. Lying flat on the back and raising the head and shoulders 
a few inches will best show the Rectus and its lineae transversae. It is well that the 
different outline of the belly in the two sexes be noted. In the male the anterior 
line is in general a nearly uniform curve from the sternum to the pubes, slightly 
more marked below the navel. In women above the navel it is almost a straight 
line, but below it the anterior curve is very marked.] 
Muscles and Fascije of the Thorax. 
The muscles exclusively connected with the bones in this region are few in num- 
ber. They are the 
Intercostales externi. 
Intercostales interni. 
Infracostales. 
Triangularis sterni. 
Levatores costarum. 420 
MUSCLES AND FASCIAE. 
Intercostal Fasciae.-A thin but firm layer of fascia covers the outer surface of 
the External intercostal and the inner surface of the Internal intercostal muscles, 
and a third layer, more delicate, is interposed between the two planes of muscular 
fibres. These are the intercostal fasciae; they are best marked in those situations 
where the muscular fibres are deficient, as between the External intercostal muscles 
and sternum in front, and between the Internal intercostals and spine behind. 
The Intercostal Muscles (Fig. 312, p. 431) are two thin planes of muscular and 
tendinous structure placed one over the other, filling up the intercostal spaces, and 
being directed obliquely between the margins of the adjacent ribs. They have 
received the name "external" and "internal," from the position they bear to one 
another. The Intercostal muscles consist of muscular and tendinous fibres, the 
latter being longer and more numerous than the former; hence the walls of the 
intercostal spaces possess very considerable strength, to which the crossing of the 
muscular fibres materially contributes. 
The External intercostals are eleven in number on each side, being attached 
to the adjacent margins of each pair of ribs, and extending from the tubercles of 
the ribs behind to the commencement of the cartilages of the ribs in front, where 
they terminate in a thin membranous aponeurosis which is continued forward to the 
sternum. They arise from the outer lip of the groove on the lower border of each 
rib, and are inserted into the upper border of the rib below. In the two lowest 
spaces they extend to the end of the cartilages. Their fibres are directed obliquely 
downward and forward, in a similar direction with those of the External oblique 
muscle. They are thicker than the Internal intercostals. 
Relations.-By their outer surface with the muscles which immediately invest 
the chest-viz. the Pectoralis major and minor, Serratus magnus, and Rhomboideus 
major, Serratus posticus superior and inferior, Scalenus posticus, Sacro-lumbalis, 
Longissimus dorsi, Cervicalis ascendens, Transversalis colli, Levatores costarum, 
and the Obliquus externus abdominis; by their internal surface with a thin layer 
of fascia which separates them from the intercostal vessels and nerve and the Inter- 
nal intercostal muscles, and behind from the pleura. 
The Internal intercostals, also eleven in number on each side, are placed on 
the inner surface of the preceding, commencing anteriorly at the sternum in the 
interspaces between the cartilages of the true ribs, and from the anterior extremities 
of the cartilages of the false ribs. They extend backward as far as the angles of 
the ribs, whence they are continued to the vertebral column by a thin aponeurosis. 
They arise from the inner lip of the groove on the lower border of each rib, as well 
as from the corresponding costal cartilage, and are inserted into the upper border of 
the rib below. Their fibres are directed obliquely downward and backward, decus- 
sating with the fibres of the preceding. 
Relations.-By their external surface with the External intercostals and the 
intercostal vessels and nerves; by their internal surface with the pleura costalis, 
Triangularis sterni, and Diaphragm. 
The Infracostales (subcostales) consist of muscular and aponeurotic fasciculi 
which vary in number and length; they arise from the inner surface of one rib, and 
are inserted into the inner surface of the first, second, or third rib below. Their 
direction is most usually oblique, like the Internal intercostals. They are most 
frequent between the lower ribs. 
The Triangularis sterni is a thin plane of muscular and tendinous fibres situ- 
ated upon the inner wall of the front of the chest. It arises from the lower part of 
the side of the sternum, from the inner surface of the ensiform cartilage, and from 
the sternal ends of the costal cartilages of the three or four lower true ribs. Its 
fibres diverge upward and outward, to be inserted by fleshy digitations into the lower 
border and inner surfaces of the costal cartilages of the second, third, fourth, and 
fifth ribs. The lowest fibres of this muscle are horizontal in their direction, and are 
continuous with those of the Transversalis; those which succeed are oblique, whilst 
the superior fibres are almost vertical. This muscle varies much in its attachment, 
not only in different bodies, but on opposite sides of the same body. MUSCLES AND FASCIAE OF THE THORAX. 
421 
Relations.-In front with the sternum, ensiform cartilage, costal cartilages, 
Internal intercostal muscles, and internal mammary vessels; behind with the pleura, 
pericardium, and anterior mediastinum. 
The Levatores costarum (Fig. 301, p. 407), twelve in number on each side, 
are small tendinous and fleshy bundles which arise from the extremities of the trans- 
verse processes of the seventh cervical and eleven upper dorsal vertebrae, and, pass- 
ing obliquely downward and outward, are inserted into the upper rough surface of 
the rib below them, between the tubercle and the angle. That for the first rib 
arises from the transverse process of the last cervical vertebra, and that for the last 
from the eleventh dorsal. The Inferior levatores divide into two fasciculi, one of 
which is inserted as above described; the other fasciculus passes down to the second 
rib below its origin; thus each of the lower ribs receives fibres from the transverse 
processes of two vertebrae. 
Nerves.-The muscles of this group are supplied by the intercostal nerves. 
Actions.-The Intercostals are the chief agents in the movement of the ribs in 
ordinary respiration. The External intercostals raise the ribs, especially their fore 
part, and so increase the capacity of the chest from before backward; at the same 
time they evert their lower borders, and so enlarge the thoracic cavity transversely. 
The Internal intercostals at the side of the thorax depress the ribs and invert their 
lower borders, and so diminish the thoracic cavity; but at the fore part of the chest 
these muscles assist the External intercostals in raising the cartilages.1 The Leva- 
tores costaruni assist the External intercostals in raising the ribs. The Triangularis 
sterni draws down the costal cartilages; it is therefore an expiratory muscle. [From 
experiments by the American Editor upon a criminal executed by hanging {Trans. 
Coll. Phys. Phila., Third Series, vol. i., 1875, p. 97), the conclusion was reached 
that the External intercostals were muscles of expiration, as they pulled the ribs* 
down, while the Internal intercostals pulled the ribs up, and were muscles of inspi* 
ration.] 
Muscles of Inspiration and Expiration.-The muscles which assist the action 
of the Diaphragm in ordinary tranquil inspiration are the Intercostals and the Leva- 
tores costarum, as above stated, and the Scaleni. When the need for more forcible 
action exists the shoulders and the base of the scapula are fixed, and then the pow- 
erful muscles of forced inspiration come into play: the chief of these are the Tra- 
pezius, the Pectoralis minor, the Serratus posticus superior and inferior, and the 
Rhomboidei. The lower fibres of the Serratus magnus may possibly assist slightly 
in dilating the chest by raising and everting the ribs. The Sterno-mastoid also, 
when the head is fixed, assists in forced inspiration by drawing up the sternum and 
by fixing the clavicle, and thus affording a fixed point for the action of the muscles 
of the chest. 
The ordinary action of expiration is hardly effected by muscular force, but 
results from a return of the walls of the thorax to a condition of rest, owing to 
their own elasticity and to that of the lungs. Forced expiratory actions are per- 
formed mainly by the flat muscles (Obliqui and Transversalis) of the abdomen, 
assisted also by the Rectus. Other muscles of forced expiration are the Internal 
intercostals and Triangularis sterni (as above mentioned), the Quadratus lumborum, 
and the Sacro-lumbalis. 
1 The view of the action of the Intercostal muscles given in the text is that which is taught by 
Hutchinson (Cycl. of Anat. and Phys., art. "Thorax"), and is usually adopted in our schools. It is, 
however, much disputed. Hamberger believed that the External intercostals act as elevators of the 
ribs or muscles of inspiration, while the Internal act in expiration. Haller taught that both sets of 
muscles act in common-viz. as muscles of inspiration; and this view is adopted by many of the best 
anatomists of the Continent, and appears supported by many observations made on the human subject 
under various conditions of disease, and on living animals in whom the muscles have been exposed 
under chloroform. The reader may consult an interesting paper by Dr. Cleland in the Journal of 
Anat. and Phys., No. II., May, 1867, p. 209, "On the Hutchinsonian Theory of the Action of the 
Intercostal Muscles," who refers also to Henle, Luschka, Budge, and Baumler, " Observations on the 
Actions of the Intercostal Muscles," Erlangen, 1860 (in New Syd. Soc.'s Year-Book for 1861, p. 69). 422 
MUSCLES AND FASCIAE. 
Diaphragmatic Region. 
Diaphragm. 
The Diaphragm (dutypay pa, a partition-wall) (Fig. 307) is a thin musculo-fibrous 
septum placed obliquely at the junction of the upper with the middle third of the 
trunk, and separating the thorax from the abdomen, forming the floor of the former 
cavity and the roof of the latter. It is elliptical, its longest diameter being from 
side to side, somewhat fan-shaped, the broad elliptical portion being horizontal; the 
narrow part, which represents the handle of the fan, vertical and joined at -right 
Fig. 307. 
Last Rih 
The Diaphragm, under surface. 
angles to the former. It is from this circumstance that some anatomists describe it 
as consisting of two portions, the upper or great muscle of the Diaphragm, and the 
lower or lesser muscle. It arises from the whole of the internal circumference of 
the thorax, being attached in front by fleshy fibres to the ensiform cartilage; on 
either side, to the inner surface of the cartilages and bony portions of the six or 
seven inferior ribs, interdigitating with the Transversalis; and behind, to two apo- 
neurotic arches named the lig amentum arcuatum externum and internum and to the 
lumbar vertebrae. The fibres from these sources vary in length : those arising from 
the ensiform appendix are very short and occasionally aponeurotic; those from the 
ligamenta arcuata, and more especially those from the ribs at the side of the chest, 
are longer, describe well-marked curves as they ascend, and finally converge to be 
inserted into the circumference of the central tendon. Between the sides of the 
muscular slip from the ensiform appendix and the cartilages of the adjoining ribs 
the fibres of the Diaphragm are deficient, the interval being filled by areolar tissue, 
covered on the thoracic side by the pleurae; on the abdominal, by the peritoneum. DIAPHRAGMATIC REGION. 
423 
[Fig. 308. 
Coronal Section of the Trunk, at the end of the twelfth rib (all the ribs except the last show in section). 
1, Trachea at-its bifurcation; 
2, Posterior wall of pericardium and the pulmonary 
veins: 
3, Inferior vena cava as it passes through the dia- 
phragm (the diaphragm is seen passing obliquely 
above the stomach and liver); 
4, (Esophagus; 
5, Duodenum; 
6, 7, Transverse colon (Henle).] 
This is consequently a weak point, and a portion 
of the contents of the abdomen may protrude into 
the chest, forming phrenic or diaphragmatic hernia, 
or a collection of pus in the mediastinum may de- 
scend through it, so as to point at the epigastrium. 
The ligamentum arcuatum internum is a ten- 
dinous arch, thrown across the upper part of the 
Psoas magnus muscle on each side of the spine. 
It is connected by one end to the outer side of 
the body of the first, and occasionally the second, 
lumbar vertebrae, being continuous with the outer 
side of the tendon of the corresponding crus; and 
by the other end to the front of the transverse 
process of the second lumbar vertebra. 
The ligamentum arcuatum externum is a thick- 
ened upper margin of the anterior lamella of the 
transversalis aponeurosis: it arches across the up- 
per part of the Quadratus lumborum. being at- 
tached by one extremity to the front of the trans- 
verse process of the second lumbar vertebra, and 
by the other to the apex and lower margin of the 
last rib. 
[Fig. 309. 
Sagittal Section of the Trunk, at the border 
of the right second rib: d. the diaphragm 
(.Henle).] 424 
MUSCLES AND FASCINE. 
To the spine the Diaphragm is connected by two crura, which are situated on 
the bodies of the lumbar vertebrae on each side of the aorta. The crura at their 
origin are tendinous in structure, the right crus, larger and longer than the left, 
arising from the anterior surface of the bodies and intervertebral substances of the 
second, third, and fourth lumbar vertebrae; the left, from the second and third, 
both blending with the anterior common ligament of the spine. A tendinous arch 
is thrown across the front of the vertebral column from the tendon of one crus to 
that of the other, beneath which pass the aorta, vena azygos major, and thoracic 
duct. The tendons terminate in two large fleshy bellies, which, with the tendinous 
portions above alluded to, are called the crura, or pillars of the diaphragm. The 
outer fasciculi of the two crura are directed upward and outward to the central ten- 
don ; but the inner fasciculi decussate in front of the aorta, and then diverge, so as 
to surround the oesophagus before ending in the central tendon. The anterior and 
larger of these fasciculi is formed by the right crus. 
The Central or Cordiform Tendon of the Diaphragm is a thin but strong ten- 
dinous aponeurosis situated at the centre of the vault formed by the muscle, imme- 
diately below' the pericardium, with which its circumference is blended. It is 
shaped somewhat like a trefoil leaf, consisting of three divisions or leaflets, sepa- 
rated from one another by slight indentations. The right leaflet is the largest, the 
middle one, directed toward the ensiform cartilage, the next in size, and the left the 
smallest. In structure the tendon is composed of several planes of fibres, which 
intersect one another at various angles and unite into straight or curved bundles- 
an arrangement which affords it additional strength. 
The Openings connected with the Diaphragm are three large and several smaller aper- 
tures. The former are the aortic, the oesophageal, and the opening for the vena cava. 
The aortic opening is the lowest and the most posterioi* of the three large aper- 
tures connected with this muscle. It is situated in the middle line, immediately in 
front of the bodies of the vertebrae, and is therefore behind the Diaphragm, not in 
it. It is an osseo-aponeurotic aperture formed by a tendinous arch thrown across 
the front of the bodies of the vertebrae, from the crus on one side to that on the 
other, and transmits the aorta, vena azygos major, thoracic duct, and occasionally 
the left sympathetic nerve. 
The oesophageal opening, elliptical in form, muscular in structure, and formed by 
the two crura, is placed above, and at the same time anterior and a little to the left 
of, the preceding. It transmits the oesophagus and pneumogastric nerves. The 
anterior margin of this aperture is occasionally tendinous, being formed by the mar- 
gin of the central tendon. 
The opening for the vena cava {foramen quadratum) is the highest; it is quad- 
rilateral in form, tendinous in structure, and placed at the junction of the right and 
middle leaflets of the central tendon, its margins being bounded by four bundles of 
tendinous fibres which meet at right angles. 
The right crus transmits the sympathetic and the greater and lesser splanchnic 
nerves of the right side; the left crus, the greater and lesser splanchnic nerves of 
the left side and the vena azygos minor. 
The Serous Membranes in relation with the Diaphragm are four in number, 
three lining its upper or thoracic surface, one its abdominal. The three serous 
membranes on its upper surface are the pleura on either side, and the serous layer 
of the pericardium, which covers the middle portion of the tendinous centre. The 
serous membrane covering its under surface is a portion of the general peritoneal 
membrane of the abdominal cavity. 
The Diaphragm is arched, being convex toward the chest and concave to the 
abdomen. The right portion forms a complete arch from before backward, being 
accurately moulded over the convex surface of the liver and having resting upon it 
the concave base of the right lung. The left portion is arched from before back- 
ward in a similar manner, but the arch is narrower in front, being encroached upon 
by the pericardium, and low'er than the right at its summit by about three-quarters of 
an inch. It supports the base of the left lung, and covers the great end of the stomach, OF THE UPPER EXTREMITY. 
425 
the spleen, and left kidney. At its circumference the Diaphragm is higher in the 
mesial line of the body than at either side ; but in the middle of the thorax the cen- 
tral portion, which supports the heart, is on a lower level than the two lateral portions. 
The height of the Diaphragm is constantly varying during respiration, the mus- 
cle being carried upward or downward from the average level: its height also varies 
according to the degree of distension of the stomach and intestines and the size of 
the liver. After a forced expiration the right arch is on a level in front with the 
fourth costal cartilage, at the side with the fifth, sixth, and seventh ribs, and behind 
with the eighth rib, the left arch being usually from one to two ribs' breadth below 
the level of the right one. In a forced inspiration it descends from one to two 
inches; its slope would then be represented by a line drawn from the ensiform car- 
tilage toward the tenth rib. 
Nerves.-The Diaphragm is supplied by the phrenic nerves and phrenic plexus 
of the sympathetic. 
Actions.-The Diaphragm is the principal muscle of inspiration. When in a 
condition of rest the muscle presents a concave, domed surface toward the abdomen ; 
when it contracts, this dome becomes much flatter, and as a consequence the level 
of the floor of the chest is lowered, and therefore the vertical diameter of the tho- 
racic cavity increased, while the abdominal cavity is encroached upon and the abdom- 
inal viscera pushed down, so as to cause a projection of the flaccid abdominal 
wall. [In inspiration also, owing to the partial fixation of the central tendon, 
partly by its attachment to the pericardium, and partly by its finding a point 
d'appui on the abdominal viscera, contraction of the Diaphragm causes elevation 
of the lower ribs and their displacement externally, thus widening the chest later- 
ally. Inspiration causes always a tendency to a vacuum in the chest, and so pro- 
duces an inrush of air by the windpipe, and of blood through the veins-an effect 
which is reversed in expiration.] When at the end of inspiration the Diaphragm 
relaxes, the abdominal walls return to their natural position; they therefore push 
up the viscera again, and these, pressing on the Diaphragm, cause it to resume its 
ordinary position of rest. 
In all expulsive acts the Diaphragm is called into action to give additional power 
to each expulsive effort. Thus, before sneezing, coughing, laughing, and crying, 
before vomiting, previous to the expulsion of the urine and feces or of the foetus 
from the womb, a deep inspiration takes place.1 
MUSCLES AND FASCIA OF THE UPPER EXTREMITY. 
The Muscles of the Upper Extremity are divisible into groups, corresponding 
with the different regions of the limb : 
Of the Shoulder. 
Posterior Scapular Region. 
Supraspinatus. 
Infraspinatus. 
Teres minor. 
Teres major. 
Anterior Thoracic Region. 
Pectoralis major. 
Pectoralis minor. 
Subclavius. 
Lateral Thoracic Region. 
Serratus magnum. 
Acromial Region. 
Deltoid. 
Anterior Scapular Region. 
Subscapularis. 
Anterior Humeral Region. 
Coraco-brachialis. 
Biceps. 
Brachialis anticus. 
Posterior Humeral Region. 
Triceps. 
Subanconeus. 
Of the Arm. 
1 For a detailed description of the general relations of the Diaphragm and its action refer to Dr. 
Sibson's Medical Anatomy. 426 
MUSCLES AND FAS CI MJ. 
Of the Forearm. 
Deep 
Layer. 
Supinator brevis. 
Extensor ossis metacarpi pollicis. 
Extensor primi internodii pollicis. 
E xtensor secundi internodii pollicis. 
Extensor indicis. 
Anterior Brachial Region. 
Pronator radii teres. 
Flexor carpi radialis. 
Palmaris longus. 
Flexor carpi ulnaris. 
Flexor sublimis digitorum. 
Superficial 
Layer. 
Or the Hand. 
Deep 
Layer. 
Flexor profundus digitorum. 
Flexor longus pollicis. 
Pronator quadratus. 
Radial Region. 
Abductor pollicis. 
Flexor ossis metacarpi pollicis (opponens). 
Flexor brevis pollicis. 
Adductor pollicis. 
Radial Region. 
Ulnar Region. 
Palmaris brevis. 
Abductor minimi digiti. 
Flexor brevis minimi digiti. 
Flexor ossis metacarpi minimi digiti (op- 
ponens). 
Supinator longus. 
Extensor carpi radialis longior. 
Extensor carpi radialis brevior. 
Posterior Brachial Region. 
Superficial 
Layer. 
Extensor communis digitorum. 
Extensor minimi digiti. 
Extensor carpi ulnaris. 
Anconeus. 
Palmar Region. 
Lumbricales. 
Interossei palmares. 
Interossei dorsales. 
Dissection of Pectoral Region and Axilla (Fig. 310).-The arm being drawn away from 
the side nearly at right angles with the trunk and rotated outward, make a vertical incision 
through the integument in the median line 
of the chest from the upper to the lowei 
part of the sternum; a second incision 
along the lower border of the Pectoral 
muscle from the ensiform cartilage to the 
inner side of the axilla; a third from the 
sternum along the clavicle as far as its 
centre; and a fourth from the middle of 
the clavicle obliquely downward, along the 
interspace between the Pectoral and Deltoid 
muscles, as low as the fold of the armpit. 
The flap of integument is then to be dis- 
sected off in the direction indicated in the 
figure, but not entirely removed, as it should 
be replaced on completing the dissection. 
If a transverse incision is now made from 
the lower end of the sternum to the side 
of the chest as far as the posterior fold of 
the armpit, and the integument reflected 
outward, the axillary space will be more 
completely exposed. 
Fig. 310. 
3.Dissection of 
SHOULDER & ARM 
</. J) is.sc at ion of 
PECTORAL REGION 
and, axilla 
2. BEND o/'ELBOW 
4 - FORE-ARM 
Fascije of the Thorax. 
The Superficial Fascia of the 
thoracic region is a loose cellulo- 
fibrous layer continuous with the su- 
perficial fascia of the neck and upper 
extremity above and of the abdo- 
men below; opposite the mamma it 
subdivides into two layers, one of 
which passes in front, the other be- 
hind that gland; and from both of 
these layers numerous septa pass into 
its substance, supporting its various 
lobes: from the anterior layer, fibrous processes pass forward to the integument and 
\f). PALM HAND 
Dissection of Upper Extremity. FASCIA! OF THE THORAX. 
427 
nipple, enclosing in their areolae masses of fat. These processes were called by Sir 
A. Cooper the ligamenta suspensoria, from the support they afford to the gland in 
this situation. On removing the superficial fascia with the mamma the Deep Fascia 
of the thoracic region is exposed: it is a thin aponeurotic lamina covering the sur- 
face of the great Pectoral muscle, and sending numerous prolongations between its 
fasciculi: it is attached in the middle line to the front of the sternum, and above to 
the clavicle: it is very thin over the upper part of the muscle, somewhat thicker in 
the interval between the Pectoralis major and Latissimus dorsi, where it closes in 
the axillary space, and divides at the outer margin of the latter muscle into two 
layers, one of which passes in front and the other behind it; these proceed as far as 
the spinous processes of the dorsal vertebrae, to which they are attached. At the 
lower part of the thoracic region this fascia is well developed, and is continuous with 
the fibrous sheath of the Recti muscles. 
Anterior Thoracic Region. 
Pectoralis major. 
Pectoralis minor. 
The Pectoralis major (Fig. 311) is a broad, thick, triangular muscle situated 
at the uppei' and fore part of the chest in front of the axilla. It arises from the 
anterior surface of the sternal half of the clavicle; from half the breadth of the 
anterior surface of the sternum as low down as the attachment of the cartilage of 
the sixth or seventh rib, its origin consisting of aponeurotic fibres which intersect 
with those of the opposite muscle; it also arises from the cartilages of all the true 
ribs, with the exception, frequently, of the first or of the seventh, or both; and 
from the aponeurosis of the External oblique muscle of the abdomen. The fibres 
from this extensive origin converge toward its insertion, giving to the muscle a 
radiated appearance. Those fibres which arise from the clavicle pass obliquely out- 
ward and downward, and are usually separated from the rest by a cellular interval: 
those from the lower part of the sternum and the cartilages of the lower true ribs 
pass upward and outward; whilst the middle fibres pass horizontally. As these 
three sets of fibres converge, they are so disposed that the upper overlap the middle 
and the middle the lower portion, the fibres of the lower portion being folded back- 
ward upon themselves, so that those fibres which are lowest in front become highest 
at their point of insertion. They all terminate in a fiat tendon, about two inches 
broad, which is inserted into the anterior bicipital ridge of the humerus. This 
tendon consists of two laminae, placed one in front of the other, and usually blended 
together below. The anterior, the thicker, receives the clavicular and upper half 
of the sternal portion of the muscle, the posterior lamina receiving the attachment 
of the lower half of the sternal portion. From this arrangement it results that the 
fibres of the upper and middle portions of the muscle are inserted into the lower 
part of the bicipital ridge, those of the lower portion into the upper part. The 
tendon at its insertion is connected with that of the Deltoid; it sends up an expan- 
sion over the bicipital groove toward the-head of the humerus ; another backward, 
which lines the groove; and a third to the fascia of the arm. [Mr. Wagstaffe 
(Journ. Anat. and Phys., 1871) has described the insertion of the Pectoralis major 
more accurately, as follows: " The fibres of the clavicular portion are inserted in 
the same order as they arise: the outermost, and particularly the deeper, fibres of 
origin are inserted at the uppermost part of the tendon; the innermost fibres, or 
those nearest to the sterno-clavicular articulation, pass down to the lowermost part 
of the tendon. The sternal portion is peculiarly arranged. It will be seen, on 
turning aside the clavicular part, that the uppermost fibres of the sternal muscle- 
i. e. those from the first costal cartilage (if, as is perhaps most usual, there is attach- 
ment to that part), or from the neighborhood of the sterno-clavicular articulation- 
pass downward under cover of the clavicular muscle, and are inserted into the 
uppermost part of the second plane of attachment to the outer bicipital ridge. 
Fibres from the sternum opposite the first intercostal space, or sometimes a little 
Subclavius. 428 
MUSCLES AND FASCIAE. 
lower, can be traced down to be inserted into the lowest part of the attachment to 
the humerus. Below these last-mentioned fibres the muscular bundles gradually 
pass under the previous ones, and ultimately the lowest fibres of origin from the apo- 
neurosis of the external oblique pass to the highest part of the third plane of inser- 
Fig. 311. 
Muscles of the Chest and Front of the Arm, superficial view. 
tion; and it is these fibres which are connected with the fibrous band passing upward 
to the head of the humerus. 
"It will thus be seen that the so-called tendon of the Pectoralis major is com- 
posed of three layers: 1, that of the clavicular portion, 2 and 3, those of the 
sternal portion, doubled upon itself below, but easily separable above. Of these 
layers, the first and second have usually about the same extent of attachment above 
and below, but the third passes considerably higher than the others."] 
Relations.-By its anterior surface with the integument, the superficial fascia, 
the Platysma, and the mammary gland; by its posterior surface, its thoracic por- 
tion, with the sternum, the ribs and costal cartilages, the Subclavius, Pectoralis ANTERIOR THORACIC REGION. 
429 
minor, Serratus magnus, and the Intercostals; its axillary portion forms the ante- 
rior wall of the axillary space and covers the axillary vessels and nerves. Its 
upper border lies parallel with the Deltoid, from which it is separated by the 
cephalic vein and descending branch of the thoracico-acromialis artery. Its lower 
border forms the anterior margin of the axilla, being at first separated from the 
Latissimus dorsi by a considerable interval, but both muscles gradually converge 
toward the outer part of the space. 
Dissection.-Detach the Pectoralis major by dividing the muscle along its attachment to the 
clavicle, and by making a vertical incision through its substance a little external to its line of 
attachment to the sternum and costal cartilages. The muscle should then be reflected outward 
and its tendon carefully examined. The Pectoralis minor is now exposed, and immediately 
above it, in the interval between its upper border and the clavicle, a strong fascia, the costo-cora- 
coid membrane. 
The Costo-coracoid Membrane protects the axillary vessels and nerves. It 
is attached -above to the edges of the Subclavian groove on the under surface of 
the clavicle, so as to enclose the Subclavius muscle; from this it passes down to 
the upper border of the Pectoralis minor. Externally it is very thick and dense, 
and forms a strong fibrous band which extends from the coracoid process to the 
first rib near to the origin of the Subclavius muscle. This portion is sometimes 
called the costo-coracoid ligament. Below it is thin, and at the upper border of the 
Pectoralis minor it splits into two layers to invest the muscle; from the lower bor- 
der of the Pectoralis minor it is continued downward to join the axillary fascia, and 
outward to join the fascia over the short head of the Biceps. The costo-coracoid 
membrane is pierced by the cephalic vein, the thoracico-acromialis artery and vein, 
superior thoracic artery, and anterior thoracic nerves. 
The Pectoralis minor (Fig. 312) is a thin, flat, triangular muscle situated at 
the upper part of the thorax, beneath the Pectoralis major. It arises by three 
tendinous cligitations from the upper margin and outer surface of the third, fourth, 
and fifth ribs, near their cartilages, and from the aponeurosis covering the Inter- 
costal muscles; the fibres pass upward and outward, and converge to form a flat 
tendon which is inserted into the anterior border of the coracoid process of the 
scapula. 
Relations.-By its anterior surface with the Pectoralis major and the superior 
thoracic vessels and nerves; by its posterior surface with the ribs, Intercostal mus- 
cles, Serratus magnus, the axillary space, and the axillary vessels and nerves. Its 
upper border is separated from the clavicle by a triangular interval, broad inter- 
nally, narrow externally, bounded in front by the costo-coracoid membrane, and 
internally by the ribs. In this space are seen the axillary vessels and nerves. 
The costo-coracoid membrane should now be removed, when the Subclavius muscle will be 
seen. 
The Subclavius is a long, thin, spindle-shaped muscle placed in the interval 
between the clavicle and the first rib. It arises by a short, thick tendon from the 
cartilage of the first rib, in front of the rhomboid ligament; the fleshy fibres pro- 
ceed obliquely upward and outward, to be inserted into a deep groove on the under 
surface of the middle third of the clavicle. 
Relations.-By its upper surface with the clavicle; by its under surface it is 
separated from the first rib by the subclavian vessels and brachial plexus of nerves. 
Its anterior surface is separated from the Pectoralis maj or by the costo-coracoid apo- 
neurosis, which, with the clavicle, forms an osteo-fibrous sheath in which the muscle 
is enclosed. 
If the costal attachment of the Pectoralis minor is divided across and the muscle reflected 
outward, the axillary vessels and nerves are brought fully into view, and should be examined. 
Nerves.-The Pectoral muscles are supplied by the anterior thoracic nerves; 
the Subclavius, by a filament from the cord formed by the union of the fifth and 
sixth cervical nerves. 
Actions.-If the arm has been raised by the Deltoid, the Pectoralis major will, 430 
MUSCLES AND FASCIAE. 
conjointly with the Latissimus dorsi and Teres major, depress it to the side of the 
chest, and, if acting singly, it will draw the arm across the front of the chest. [To 
show the action of the Pectoralis major on the model, let him place his arm on your 
shoulder or other similar obstacle about the same level, and press down. Notice 
especially how the axilla is then well defined. . In muscular models the clavicular 
portion will sometimes form one distinct bundle, and the sternal be divided into 
several, and the groove between the sternal and clavicular heads will be well 
marked. The furrow between the Pectoralis major and the Deltoid is always well 
marked, though ill-limited when the muscles are at rest. Its upper end is a wide 
triangular depression, while the lower portion is linear. The marked difference in 
the appearance of the chest when the arm is hanging down and when raised should 
be observed. Simple raising of the arm stretches out the Pectoralis, effaces in great 
part its lower border, flattens the chest, and displaces the nipple of that side 
markedly upward. Letting the arm fall, the muscles are gathered again into a 
large mass with a curved lower border. Partial lifting of the arm makes the 
axilla more marked, but complete elevation nearly effaces it.] The Pectoralis 
minor depresses the point of the shoulder, drawing the scapula downward and 
inward to the thorax. The Subclavius depresses the shoulder, drawing the clav- 
icle downward and forward. When the arms are fixed, all three muscles act upon 
the ribs, drawing them upward and expanding the chest, and thus becoming very 
important agents in forced inspiration. Asthmatic patients always assume an atti- 
tude which fixes the shoulders, so that all these muscles may be brought into action 
to assist in dilating the cavity of the chest. 
Lateral Thoracic Region. 
Serratus magnus. 
The Serratus magnus (Fig- 312) is a broad, thin, and irregularly quadrilateral 
muscle situated at the upper part and side of the chest. It arises by nine fleshy 
digitations from the outer surface and upper border of the eight upper ribs (the 
second rib having two), and from the aponeurosis covering the upper intercostal 
spaces, and is inserted into the whole length of the anterior aspect of the posterior 
border of the scapula. This muscle has been divided into three portions-a supe- 
rior, middle, and inferior-on account of the difference in the direction and in the 
extent of attachment of each part. The upper portion, separated from the rest by 
a cellular interval, is a narrow but thick fasciculus which arises by two digitations 
from the first and second ribs, and from the aponeurotic arch between them; its 
fibres proceed upward, outward, and backward, to be inserted into the triangular 
smooth surface on the anterior aspect of the superior angle of the scapula. The 
middle portion of the muscle arises by three digitations from the second, third, and 
fourth ribs; it forms a thin and broad muscular layer, which proceeds horizontally 
backward to be inserted into the posterior border of the scapula between the supe- 
rior and inferior angles. The lower portion arises from the fifth, sixth, seventh, 
and eighth ribs by four digitations, in the intervals between which are received 
corresponding processes of the External oblique; the fibres pass upward, outward, 
and backward, to be inserted into the anterior surface of the inferior angle of the 
scapula by an attachment partly muscular, partly tendinous. 
Relations.-This muscle is covered in front by the Pectoral muscles; behind, 
by the Subscapularis; above, by the axillary vessels and nerves. Its deep surface 
rests upon the ribs and Intercostal muscles. 
Nerves.-The Serratus magnus is supplied by the posterior thoracic nerve. 
Actions.-The Serratus magnus, as a whole, carries the scapula forward and at 
the same time raises the vertebral border of the bone. It is therefore concerned in 
the action of pushing. Its lower and stronger fibres move forward the lower angle 
and assist the Trapezius in rotating the bone round an axis through its centre, and 
thus assists this muscle in raising the acromion and supporting weights upon the 
shoulder. It is possible that when the shoulders are fixed the lower fibres may assist LATERAL THORACIC REGION. 
431 
in raising and everting the ribs, but it is not the important inspiratory muscle which 
it was formerly believed to be. [To show its slips of origin on the living model, 
Fig. 312. 
Muscles of the Chest and Front of the Arm, with the boundaries of the axilla. 
let him simply lift the arm and breathe deeply; or, better, let him cross his arms 
behind the back and bend backward.] 
Dissection.-After completing the dissection of the axilla, if the muscles of the back have 
been dissected the upper extremity should be separated from the trunk. Saw through the 
clavicle at its centre, and then cut through the muscles which connect the scapula and arm with 
the trunk-viz. the Pectoralis minor in front, Serratus magnus at the side, and the Levator 
anguli scapulse, the Rhomboids, Trapezius, and Latissimus dorsi behind. These muscles should 
be cleaned and traced to their respective insertions. Then make an incision through the integu- 
ment, commencing at the outer third of the clavicle and extending along the margin of that 
bone, the acromion process, and spine of the scapula; the integument should be dissected from 
above downward and outward, when the fascia covering the Deltoid is exposed (Fig. 310, No. 3). 
The Superficial Fascia of the upper extremity is a thin cellulo-fibrous lamina 
containing between its layers the superficial veins and lymphatics and the cutaneous 
nerves. It is most distinct in front of the elbow, and contains very large superficial 
veins and nerves; in the hand it is hardly demonstrable, the integument being closely 
adherent to the deep fascia by dense fibrous bands. Small subcutaneous bursae are 
found in this fascia, over the acromion, the olecranon, and the knuckles. The deep 
fascia of the upper extremity comprises the aponeurosis of the shoulder, arm, and 
forearm, the anterior and posterior annular ligaments of the carpus and the palmar 
fascia. These will be considered in the description of the muscles of-the several 
regions. 432 
MUSCLES AND FASCIAE. 
Acromial Region. 
Deltoid. 
The Deep Fascia covering the Deltoid (deltoid aponeurosis) is a thick and 
strong fibrous layer which covers the outer surface of the muscle and sends down 
numerous prolongations between its fasciculi; it is continuous internally with the 
fascia covering the great Pectoral muscle; behind, with that covering the Infra- 
spinatus and back of the arm: above, it is attached to the clavicle, the acromion, 
and spine of the scapula. 
The Deltoid (Fig. 311) is a large, thick, triangular muscle which gives the 
rounded outline to the shoulder, and has received its name from its resemblance to 
the Greek letter A reversed. It surrounds the shoulder-joint in the greater part of 
its extent, covering it on its outer side and in front and behind. It arises from the 
outer third of the anterior border and upper surface of the clavicle, from the outer 
margin and upper surface of the acromion process, and from the whole length of the 
lower lip of the posterior border of the spine of the scapula. From this extensive 
origin the fibres converge toward their insertion, the middle passing vertically, the 
anterior obliquely backward, the posterior obliquely forward; they unite to form a 
thick tendon which is inserted into a rough prominence on the middle of the outer 
side of the shaft of the humerus. This muscle is remarkably coarse in texture, and 
the arrangement of its muscular fibres is somewhat peculiar: the central portion of 
the muscle-that is to say, the part arising from the acromion process-consists of 
oblique fibres which arise in a bipenniform manner from the sides of intramuscular 
aponeuroses or tendons, generally four in number, which are attached above to the 
acromion process and pass downward parallel to one another in the substance of the 
muscle. The oblique muscular fibres thus formed are inserted into similar tendinous 
insertions, generally three in number, which pass upward from the insertion of the 
muscle into the humerus and alternate with the descending septa. The lateral por- 
tions of the muscle-that is to say, the fibres arising from the clavicle and spine of 
the scapula-are not arranged in this manner, but consist of parallel fasciculi pass- 
ing from their origin above to be inserted into the margins of the inferior tendon. 
Relations.-By its superficial surface with the integument, the superficial 
fascia, Platysma, and supra-acromial nerves. Its deep surface is separated from 
the head of the humerus by a large sacculated synovial bursa, and covers the 
coracoid process, coraco-acromial ligament, Pectoralis minor, Coraco-brachialis, 
both heads of the Biceps, tendon of the Pectoralis major, insertions of the 
Supraspinatus, Infraspinatus, and Teres minor, the scapular and external heads 
of the Triceps, the circumflex vessels and nerve, and the humerus. Its anterior 
border is separated from the Pectoralis major by a cellular interspace which lodges 
the cephalic vein and descending branch of the acromial thoracic artery. Its pos- 
terior border rests on the Infraspinatus and Triceps muscles. 
Nerves.-The Deltoid is supplied by the circumflex nerve. 
Actions.-The Deltoid raises the arm directly from the side, so as to bring it at 
right angles with the trunk. Its anterior fibres, assisted by the Pectoralis major, 
draw the arm forward; and its posterior fibres, aided by the Teres major and 
Latissimus dorsi, draw it backward. [Show it on the model by resisting elevation 
of the arm directly outward, or by his lifting a heavy weight in the same direction. 
Its coarse texture in thin but muscular models is often thus well shown, even 
through the skin, and is a good illustration of this form of the structure of muscle. 
(See p. 362.) Its insertion is marked by a depression.] 
Dissection.-Divide the Deltoid across near the upper part by an incision carried along the 
margin of the clavicle, the acromion process, and spine of the scapula; and reflect it downward: 
the bursa will be seen on its under surface, as well as the circumflex vessels and nerve. The 
insertion of the muscle should be carefully examined. POSTERIOR SCAPULAR REGION. 
433 
Anterior Scapular Region. 
Subscapularis. 
The Subscapular Fascia is a thin membrane attached to the entire circum- 
ference of the subscapular fossa, and affording attachment by its inner surface to 
some of the fibres of the Subscapularis muscle: when this is removed the Sub- 
scapularis muscle is exposed. 
The Subscapularis (Fig. 312) is a large triangular muscle which fills up the 
subscapular fossa, arising from its internal two-thirds, with the exception of a nar- 
row margin along the posterior border and the surfaces at the superior and inferior 
angles which afford attachment to the Serratus magnus. Some fibres arise from 
tendinous laminae which intersect the muscle and are attached to ridges on the bone, 
and others from an aponeurosis which separates the muscle from the Teres major 
and the long head of the Triceps. The fibres pass outward, and, gradually con- 
verging, terminate in a tendon which is inserted into the lesser tuberosity of the 
humerus. Those fibres which arise from the axillary border of the scapula are 
inserted into the neck of the humerus to the extent of an inch below the tuberosity. 
The tendon of the muscle is in close contact with the capsular ligament of the 
shoulder-joint, and glides over a large bursa which separates it from the base of the 
coracoid process. This bursa communicates with the cavity of the joint by an 
aperture in the capsular ligament. 
Relations.-By its anterior surface with the Serratus magnus, Coraco-bra- 
chialis, and Biceps, and the axillary vessels and nerves; by its posterior surface 
with the scapula, the subscapular vessels and nerves, and the capsular ligament of 
the shoulder-joint. Its lower border is contiguous with the Teres major and Latis- 
simus dorsi. 
Nerves.-It is supplied by the upper and lower subscapular nerves. 
Actions.-The Subscapularis rotates the head of the humerus inward; when 
the arm is raised it draws the humerus downward. It is a powerful defence to 
the front of the shoulder-joint, preventing displacement of the head of the bone 
forward. 
Posterior Scapular Region (Fig. 313). 
Supraspinatus. 
Infraspinatus. 
Teres minor. 
Teres major. 
Dissection.-To expose these muscles, and to examine their mode of insertion into the 
humerus, detach the Deltoid and Trapezius from their attachment to the spine of the scapula 
and acromion process. Remove the clavicle by dividing the ligaments connecting it with the 
coracoid process, and separate it at its articulation with the scapula : divide the acromion pro- 
cess near its root with a saw. The fragments being removed, the tendons of the posterior Scap- 
ular muscles will be fully exposed, and can be examined. A block should be placed beneath 
the shoulder-joint, so as to make the muscles tense. 
The Supraspinous Fascia is a thick and dense membranous layer, which com- 
pletes the osseo-fibrous case in which the Supraspinatus muscle is contained, afford- 
ing attachment by its inner surface to some of the fibres of the muscle. It is thick 
internally, but thinner externally under the coraco-acromial ligament. When this 
fascia is removed the Supraspinatus muscle is exposed. 
The Supraspinatus muscle occupies the whole of the supraspinous fossa, arising 
from its internal two-thirds and from the strong fascia which covers its surface. 
The muscular fibres converge to a tendon which passes across the capsular ligament 
of the shoulder-joint, to which it is intimately adherent, and is inserted into the 
highest of the three facets on the great tuberosity of the humerus. 
Relations.-By its upper surface with the Trapezius, the clavicle, the acro- 
mion, the coraco-acromial ligament, and the Deltoid; by its under surface with 
the scapula, the suprascapular vessels and nerve, and upper part of the shoulder- 
joint. 
The Infraspinous Fascia is a dense fibrous membrane covering in the Infraspi- 434 
MUSCLES AND FASCIAE. 
natus muscle, and attached to the circumference of the infraspinous fossa: it affords 
attachment by its inner surface to some fibres of that muscle. At the point where 
the infraspinatus ceases to be covered by the Deltoid this fascia gives off a strong 
process which divides into two to enclose the Deltoid muscle: one layer passes over 
the muscle forming the Deltoid fascia already described, the other passes beneath 
the deltoid to the shoulder-joint. 
The Infraspinatus is a thick triangular muscle which occupies the chief part of 
the infraspinous fossa, arising by fleshy fibres from its internal two-thirds, and by 
tendinous fibres from the ridges on its surface: it also arises from a strong fascia 
which covers it externally and separates it from the Teres major and minor. The 
fibres converge to a tendon which glides over the external border of the spine of 
the scapula, and, passing across the capsular ligament of the shoulder-joint, is inserted 
Fig. 313. 
Muscles on the Dorsum of the Scapula and the Triceps. 
into the middle facet on the great tuberosity of the humerus. The tendon of this 
muscle is occasionally separated from the spine of the scapula by a synovial bursa 
which communicates with the synovial membrane of the shoulder-joint. 
Relations.-By its posterior surface with the Deltoid, the Trapezius, Latissi- 
mus dorsi, and the integument; by its anterior surface with the scapula, from which 
it is separated by the suprascapular and dorsalis scapulae vessels, and with the capsu- 
lar ligament of the shoulder-joint. Its lower border is in contact with the Teres 
minor, and occasionally united with it, and with the Teres major. 
The Teres minor is a narrow, elongated muscle which lies along the inferior 
border of the scapula. It arises from the dorsal surface of the axillary border of 
the scapula for the upper two-thirds of its extent, and from two aponeurotic laminae, 
one of which separates this muscle from the Infraspinatus, the other from the Teres 
major; its fibres pass obliquely upward and outward, and terminate in a tendon ANTERIOR HUMERAL REGION. 
435 
which is inserted into the lowest of the three facets on the great tuberosity of the 
humerus, and by fleshy fibres into the humerus immediately below it. The tendon 
of this muscle passes across the capsular ligament of the shoulder-joint. 
Relations.-By its posterior surface with the Deltoid, the Latissimus dorsi, and 
the integument; by its anterior surface with the scapula, the dorsal branch of the 
subscapular artery, the long head of the Triceps, and the shoulder-joint; by its 
upper border with the Infraspinatus; by its lower border with the Teres major, 
from which it is separated anteriorly by the long head of the Triceps. 
The Teres major is a broad and somewhat flattened muscle which arises from the 
dorsal aspect of the inferior angle of the scapula, from the fibrous septa interposed 
between it and the Teres minor and Infraspinatus; the fibres are directed upward 
and outward, and terminate in a flat tendon about two inches in length, which is 
inserted into the posterior bicipital ridge of the humerus. The tendon of this mus- 
cle at its insertion into the humerus lies behind that of the Latissimus dorsi, from 
which it is separated by a synovial bursa, the two tendons being, however, united 
along their lower borders for a short distance. 
Relations.-By its posterior surface with the integument, from which it is 
separated internally by the Latissimus dorsi, and externally by the long head of the 
Triceps; by its anterior surface with the Subscapularis, Latissimus dorsi, Coraco- 
brachialis, short head of the Biceps, the axillary vessels, and brachial plexus of 
nerves. Its upper border is at first in relation with the Teres minor, from which it 
is afterward separated by the long head of the Triceps. Its lower border forms, 
in conjunction with the Latissimus dorsi, part of the posterior boundary of the 
axilla. 
Nerves.-The Supra- and Infra-spinatus muscles are supplied by the suprascap- 
ular nerve; the Teres minor, by the circumflex ; and the Teres major, by the lower 
subscapular. 
Actions.-The Supraspinatus assists the Deltoid in raising the arm from the 
side, and fixes the head of the humerus in its socket. The Infraspinatus and Teres 
minor rotate the head of the humerus outward: when the arm is raised they assist 
in retaining it in that position and carrying it backward. One of the most import- 
ant uses of these three muscles is the great protection they afford to the shoulder- 
joint, the Supraspinatus supporting it above and preventing displacement of the 
head of the humerus upward, whilst the Infraspinatus and Teres minor protect it 
behind and prevent dislocation backward. The Teres major assists the Latissimus 
dorsi in drawing the humerus downward and backward when previously raised, and 
rotating it inward: when the arm is fixed, it may assist the Pectoral and Latissimus 
dorsi muscles in drawing the trunk forward. [The Supra- and Infra-spinatus and 
Teres minor show rather obscurely on the model when elevation and external rota- 
tion of the arm are resisted. To show the Teres major excellently, let him hang by 
one arm from a ring, or with his hand to the belly and elbow to the side let him 
attempt external rotation of his arm while you resist it. Pressing down on an 
obstacle also shows it.] 
Anterior Humeral Region (Fig. 312). 
Coraco-brachialis. 
Biceps. 
Brachialis anticus. 
Dissection.-The arm being placed on the table with, the front surface uppermost, make a 
vertical incision through the integument along the middle line from the outer extremity of the 
anterior fold of the axilla to about two inches below the elbow-joint, where it should be joined 
by a transverse incision extending from the inner to the outer side of the forearm ; the two flaps 
being reflected on either side, the fascia should be examined (Fig. 310). 
The Deep Fascia of the arm, continuous with that covering the shoulder and 
front of the great Pectoral muscle, is attached above to the clavicle, acromion, and 
spine of the scapula; it forms a thin, loose, membranous sheath investing the mus- 
cles of the arm, sending down septa between them, and composed of fibres disposed 
in a circular or spiral direction and connected together by vertical and oblique fibres. 436 
MUSCLES AND FASCIAE. 
It differs in thickness at different parts, being thin over the Biceps, but thicker 
where it covers the Triceps and over the condyles of the humerus: it is strength- 
ened by fibrous aponeuroses, derived from the Pectoralis major and Latissimus dorsi 
on the inner side, and from the Deltoid externally. On either side it gives off a 
strong intermuscular septum which is attached to the condyloid ridge and condyle 
of the humerus. These septa serve to separate the muscles of the anterior from 
those of the posterior brachial region. The external intermuscular septum extends 
from the lower part of the anterior bicipital ridge, along the external condyloid ridge, 
to the outer condyle; it is blended with the tendon of the Deltoid, gives attachment 
to the Triceps behind, to the Brachialis anticus, Supinator longus, and Extensor 
carpi radialis longior in front, and is perforated by the musculo-spiral nerve and 
superior profunda artery. The internal intermuscular septum, thicker than the pre- 
ceding, extends from the lower part of the posterior lip of the bicipital groove below 
the Teres major, along the internal condyloid ridge to the inner condyle: it is 
blended with the tendon of the Coraco-brachialis, and affords attachment to the 
Triceps behind and the Brachialis anticus in front. It is perforated by the ulnar 
nerve and the inferior profunda and anastomotic arteries. At the elbow the deep 
fascia is attached to all the prominent points round the joint, and is continuous with 
the fascia of the forearm. On the removal of this fascia the muscles of the anterior 
humeral region are exposed. 
The Coraco-brachialis, the smallest of the three muscles in this region, is situ- 
ated at the upper and inner part of the arm. It arises by fleshy fibres from the apex 
of the coracoid process, in common with the short head of the Biceps, and from the 
intermuscular septum between the two muscles: the fibres pass downward, back- 
ward, and a little outward, to be inserted by means of a flat tendon into a rough 
ridge at the middle of the inner side of the shaft of the humerus between the origins 
of the Triceps and Brachialis anticus. It is perforated by the musculo-cutaneous 
nerve. The inner border of the muscle forms a guide to the position of the brachial 
artery in tying the vessel in the upper part of its course. 
Relations.-By its anterior surface with the Deltoid and Pectoralis major above, 
and at its insertion with the brachial vessels and median nerve which cross it; by 
its posterior surface with the tendons of the Subscapularis, Latissimus dorsi, and 
Teres maj or, the short head of the Triceps, the humerus, and the anterior circumflex 
vessels; by its inner border with the brachial artery and the median and musculo- 
cutaneous nerves ; by its outer border with the short head of the Biceps and Brachi- 
alis anticus. 
The Biceps [flexor cubiti] is a long, fusiform muscle occupying the whole of 
the anterior surface of the arm, and divided above into two portions or heads, from 
which circumstance it has received its name. The short [or coracoid] head arises 
by a thick flattened tendon from the apex of the coracoid process, in common with 
the Coraco-brachialis. The long [or glenoid] head arises from the upper margin of 
the glenoid cavity by a long rounded tendon, which is continuous with the glenoid 
ligament. This tendon arches over the head of the humerus, being enclosed in a 
special sheath of the synovial membrane of the shoulder-joint; it then pierces the 
capsular ligament at its attachment to the humerus, and descends in the bicipital 
groove, in which it is retained by a fibrous prolongation from the tendon of the 
Pectoralis major. The fibres from this tendon form a rounded belly, and about the 
middle of the arm join with the portion of the muscle derived from the short head. 
The belly of the muscle, narrow and somewhat flattened, terminates above the elbow 
in a flattened tendon which is inserted into the back part of the tuberosity of the 
radius, a synovial bursa being interposed between the tendon and the front of the 
tuberosity. The tendon of the muscle is thin and broad; as it approaches the 
radius it becomes narrow and twisted upon itself, being applied by a flat surface to 
the back part of the tuberosity: opposite the bend of the elbow the tendon gives 
off from its inner side a broad aponeurosis, the bicipital fascia (semilunar fascia}, 
which passes obliquely downward and inward across the brachial artery and is con- 
tinuous with the fascia of the forearm (Fig. 311). The inner border of this muscle ANTERIOR HUMERAL REGION. 
437 
forms a guide to the position of the vessel in tying the brachial artery in the middle 
of the arm.1 
Relations.-Its anterior surface is overlapped above by the Pectoralis major 
and Deltoid; in the rest of its extent it is covered by the superficial and deep 
fasciae and the integument. Its posterior surface rests on the shoulder-joint and 
humerus, from which it is separated by the Subscapularis, Teres major, Latissimus 
dorsi, Brachialis anticus, and the musculo-cutaneous nerve. Its inner border is in 
relation with the Coraco-brachialis, the bra- 
chial vessels, and median nerve; its outer bor- 
der, with the Deltoid and Supinator longus. 
The Brachialis anticus is a broad muscle 
which covers the elbow-joint and the lower 
half of the front of the humerus. It is some- 
what compressed from before backward, and 
is broader in the middle than at either ex- 
tremity. It arises from the lower half of the 
outer and inner surfaces of the shaft of the 
humerus, and commences above at the inser- 
tion of the Deltoid, which it embraces by two 
angular processes. Its origin extends below 
to within an inch of the margin of the artic- 
ular surface, and is limited on each side by 
the external and internal borders of the shaft 
of the humerus. It also arises from the in- 
termuscular septa on each side, but more ex- 
tensively from the inner than the outer. Its 
fibres converge to a thick tendon, which is 
inserted into a rough depression on the an- 
terior surface of the coronoid process of the 
ulna, being received into an interval between 
two fleshy slips of the Flexor digitorum pro- 
fundus. 
Relations.-By its anterior surface with 
the Biceps, the brachial vessels, musculo-cuta- 
neous, and median nerves; by its posterior sur- 
face with the humerus and front of the elbow- 
joint; by its inner border with the Triceps, 
ulnar nerve, and Pronator radii teres, from 
which it is separated by the intermuscular septum; by its outer border with the 
musculo-spiral nerve, radial recurrent artery, the Supinator longus, and Extensor 
carpi radialis longior. 
Nerves.-The muscles of this group are supplied by the musculo-cutaneous 
nerve. The Brachialis anticus usually receives an additional filament from the 
musculo-spiral. 
Actions.-The Coraco-brachialis draws the humerus forward and inward, and 
at the same time assists in elevating it toward the scapula. The Biceps and Bra- 
chialis anticus are flexors of the forearm: the former muscle is also a supinator, 
and serves to render tense the fascia of the forearm by means of the broad apo- 
neurosis given off from its tendon. When the forearm is fixed the Biceps and Bra- 
chialis anticus flex the arm upon the forearm, as is seen in efforts of climbing. The 
Brachialis anticus forms an important defence to the elbow-joint. [The Coraco- 
brachialis is well seen by resisting the model's folding his arms across the chest. 
[Fig. 314. 
Section through the Middle of the Right Upper 
Arm (Heath, from BCraud): 1, biceps; 2, cepha- 
lic vein; 3, brachial vessels; 4, musculo-cutane- 
ous nerve; 5, median nerve ; 6, brachialis anti- 
cus; 7, ulnar nerve; 8, musculo-spiral nerve; 9, 
basilic vein with internal cutaneous nerves; 10, 
superior profunda vessels; 11, inferior profunda 
vessels; 12, triceps with intramuscular aponeur- 
osis.] 
1 A third head to the Biceps is occasionally found (Theile says as often as once in eight or nine 
subjects), arising at the upper and inner part of the Brachialis anticus, with the fibres of which it is 
continuous, and inserted into the bicipital fascia and inner side of the tendon of the Biceps. In most 
cases this additional slip passes behind the brachial artery in its course down the arm. Occasionally 
the third head consists of two slips, which pass down, one in front, the other behind the artery, con- 
cealing the vessel in the lower half of the arm. 438 
MUSCLES AND FASCIAE. 
The Biceps is shown by resisted flexion at the elbow or by lifting the body by 
seizing rings or a bar. Both when at rest and in action the triangular flat corre- 
sponding to its tendon should be observed. If the attempt be made to lift a heavy 
table, the arm being flexed at a right angle, the bicipital fascia will spring into 
relief, especially its crescentic internal border, and the finger can be thrust far 
under it. The Brachialis anticus, especially on the outside of the Biceps, shows 
by resisted flexion of the forearm.] 
Posterior Humeral Region. 
Triceps. 
Subanconeus. 
The Triceps [extensor cubiti] (Fig. 313) is situated on the back of the arm, 
extending the entire length of the posterior surface of the humerus. It is of large 
size and divided above into three parts, hence its name. These three portions have 
been named-(1) the middle, scapular, or long head; (2) the external or long humeral; 
and (3) the internal or short humeral head. 
The middle or scapular head arises by a flattened tendon from a rough trian- 
gular depression immediately below the glenoid cavity, being blended at its upper 
part with the capsular ligament; the muscular fibres pass downward between the 
two other portions of the muscle and join with them in the common tendon of 
insertion. 
The external head arises from the posterior surface of the shaft of the humerus, 
between the insertion of the Teres minor and the upper part of the musculo-spiral 
groove, from the external border of the humerus and the external intermuscu- 
lar septum: the fibres from this origin converge toward the common tendon of 
insertion. 
The internal head arises from the posterior surface of the shaft of the humerus, 
below the groove for the musculo-spiral nerve, commencing above, narrow and 
pointed, below the insertion of the Teres major, and extending to within an inch 
of the trochlear surface: it also arises from the internal border of the humerus and 
internal intermuscular septum. The fibres of this portion of the muscle are directed, 
some downward to the olecranon, whilst others converge to the common tendon of 
insertion. 
The common tendon of the Triceps commences about the middle of the back part 
of the muscle: it consists of two aponeurotic laminae, one of which is subcutaneous 
and covers the posterior surface of the muscle for the lower half of its extent; the 
other is more deeply seated in the substance of the muscle: after receiving the 
attachment of the muscular fibres they join together above the elbow, and are 
inserted into the back part of the upper surface of the olecranon process, a small 
bursa, occasionally multilocular, being situated on the front part of this surface 
beneath the tendon. 
The long head of the Triceps descends between the Teres minor and Teres major, 
dividing the triangular space between these two muscles and the humerus into two 
smaller spaces, one triangular, the other quadrangular (Fig. 313). The triangular 
space contains the dorsalis scapulae vessels; it is bounded by the Teres minor above, 
the Teres major below, and the scapular head of the Triceps externally: the quad- 
rangular space transmits the posterior circumflex vessels and nerve; it is bounded 
by the Teres minor above, the Teres major below, the scapular head of the Triceps 
internally, and the humerus externally. 
Relations.-By its posterior surface with the Deltoid above: in the rest of 
its extent it is subcutaneous; by its anterior surface with the humerus, musculo- 
spiral nerve, superior profunda vessels, and back part of the elbow-joint. Its mid- 
dle or long head is in relation behind with the Deltoid and Teres minor; in front 
with the Subscapularis, Latissimus dorsi, and Teres major. 
The Subanconeus is a small muscle distinct from the Triceps, and analogous to 
the Subcrureus in the lower limb. It may be exposed by removing the Triceps MUSCLES OF THE FOREARM. 
439 
from the lower part of the humerus. It consists of one or two slender fasciculi 
which arise from the humerus immediately above the olecranon fossa, and are 
inserted into the posterior ligament of the elbow-joint. 
Nerves.-The Triceps and Subanconeus are supplied by the musculo-spiral 
nerve. 
Actions.-The Triceps is the great Extensor muscle of the forearm, serving, 
when the forearm is flexed, to draw it into a right line with the arm. It is the 
direct antagonist of the Biceps and Brachialis anticus. When the arm is extended 
the long head of the muscle may assist the Teres major and Latissimus dorsi in 
drawing the humerus backward. The long head of the Triceps protects the under 
part of the shoulder-joint, and prevents displacement of the head of the humerus 
downward and backward. [Attempted over-extension of the forearm by the model 
well shows the Triceps. Notice especially the large roll of the external head. 
When at rest, but especially in action, the large flat corresponding to the tendon is 
well seen.] 
Muscles of the Forearm, 
[The student should observe the difference between the shape of the arm and 
forearm. The arm in section is an oval flattened from side to side; the forearm, 
an oval flattened antero-posteriorly. The forearm on its internal border, in conse- 
quence of the structure of the Flexor carpi ulnaris, is one uniform curve from the 
internal condyle to the wrist; on its external border the curve begins well above 
the elbow over the Supinator longus, and at a considerable distance above the wrist 
terminates rather abruptly as a straight line, thus marking the transition from the 
muscular bellies of the radial group of muscles to their tendons.] 
Dissection.-To dissect the forearm place the limb in the position indicated in Fig. 310 ; 
make a vertical incision along the middle line from the elbow to the wrist, and a transverse 
incision at each extremity of this: the flaps of integument being removed, the fascia of the 
forearm is exposed. 
The Deep Fascia of the forearm, continuous above with that enclosing the arm, 
is a dense, highly glistening aponeurotic investment which forms a general sheath 
enclosing the muscles in this region; it is attached behind to the olecranon and 
posterior border of the ulna, and gives off from its inner surface numerous inter- 
muscular septa which enclose each muscle separately. Below it is continuous in 
front with the anterior annular ligament, and forms a sheath for the tendon of the 
Palmaris longus muscle, which passes over the annular ligament to be inserted into 
the palmar fascia. Behind, near the wrist-joint, it becomes much thickened by the 
addition of many transverse fibres, and forms the posterior annular ligament. It 
consists of circular and oblique fibres connected together by numerous vertical 
fibres. It is much thicker on the dorsal than on the palmar surface, and at the 
lower than at the upper part of the forearm, and is strengthened by tendinous fibres 
derived from the Brachialis anticus and Biceps in front and from the Triceps behind. 
Its inner surface gives origin to muscular fibres, especially at the upper part of the 
inner and outer sides of the forearm, and forms the boundaries of a series of con- 
ical-shaped cavities in which the muscles are contained. Besides the vertical septa 
separating each muscle, transverse septa are given off both on the anterior and pos- 
terior surfaces of the forearm, separating the deep from the superficial layer of mus- 
cles. Numerous apertures exist in the fascia for the passage of vessels and nerves; 
one of these, of large size, situated at the front of the elbow, serves for the passage 
of a communicating branch between the superficial and deep veins. 
The muscles of the forearm may be subdivided into groups corresponding to the 
region they occupy. One [the ulnar] group occupies the inner and anterior aspect 
of the forearm, and comprises the Flexor and Pronator muscles ; another [the radial] 
group occupies its outer side; and a third [the posterior] its posterior aspect. The 
two latter groups include all the Extensor and Supinator muscles. 440 
MUSCLES AND FASCIAE. 
Anterior Brachial Region. 
Pronator radii teres. 
Flexor carpi radialis. 
Superficial Layer. 
Flexor carpi ulnaris. 
Flexor sublimis digitorum. 
These muscles take origin from the internal condyle of the humerus by a common 
tendon. 
The Pronator radii teres arises by two heads. One, the larger and more super- 
ficial, arises from the humerus immediately above the internal condyle, and from the 
tendon common to the origin of the other muscles; 
also from the fascia of the forearm and intermuscu- 
lar septum between it and the Flexor carpi radialis. 
The other head is a thin fasciculus which arises 
from the inner side of the coronoid process of the 
ulna, joining the preceding at an acute angle. Be- 
tween the two heads passes the median nerve. The 
muscle passes obliquely across the forearm from the 
inner to the outer side, and terminates in a flat ten- 
don which turns over the outer margin of the radius 
and is inserted into a rough ridge at the middle of 
the outer surface of the shaft of that bone. 
Relations.-By its anterior surface with the 
deep fascia, the Supinator longus, and the radial 
vessels and nerve ; by its posterior surface with the 
Brachialis anticus, Flexor sublimis digitorum, the 
median nerve, and ulnar artery, the small or deep 
head being interposed between the two latter struc- 
tures. Its outer border forms the inner boundary 
of a triangular space in which is placed the brachial 
artery, median nerve, and tendon of the Biceps mus- 
cle. Its inner border is in contact with the Flexor 
carpi radialis. 
The Flexor carpi radialis lies on the inner side 
of the preceding muscle. It arises from the internal 
condyle by the common tendon, from the fascia of 
the forearm, and from the intermuscular septa be- 
tween it and the Pronator teres on the outside, the 
Palmaris longus internally, and the Flexor sublimis 
digitorum beneath. Slender and aponeurotic in 
structure at its commencement, it increases in size, 
and terminates in a tendon which forms the lower 
two-thirds of its length. This tendon passes through 
a canal on the outer side of the annular ligament, 
runs through a groove in the os trapezium (which is 
converted into a canal by a fibrous sheath and lined 
by a synovial membrane), and is inserted into the 
base of the metacarpal bone of the index finger. 
The radial artery lies between the tendon of this 
muscle and the Supinator longus, and may easily be 
tied in this situation. 
Relations.-By its superficial surface with the 
deep fascia and the integument; by its deep surface 
with the Flexor sublimis digitorum, Flexor longus 
poliicis, and wrist-joint; by its outer border with 
the Pronator radii teres and the radial vessels; by 
its inner border with the Palmaris longus above and the median nerve below. 
Palmaris longus. 
Fig. 315. 
Front of the Left Forearm, superficial 
muscles. ANTERIOR BRACHIAL REGION. 
441 
The Palmaris longus is a slender, fusiform muscle lying on the inner side of 
the preceding. It arises from the inner condyle of the humerus by the common 
tendon, from the deep fascia and the intermuscular septa between it and the adjacent 
muscles. It terminates in a slender flattened tendon which passes over the annular 
ligament to end in the palmar fascia, frequently sending a tendinous slip to the short 
muscles of the thumb. This muscle is often absent. 
Relations.-By its superficial surface with the deep fascia; by its deep surface 
with the Flexor digitorum sublimis; internally with the Flexor carpi ulnaris; ex- 
ternally with the Flexor carpi radialis. The median nerve lies close to the tendon 
just above the wrist, on its inner and posterior side. 
The Flexor carpi ulnaris lies along the ulnar side of the forearm. It arises 
by two heads connected by a tendinous arch, beneath which pass the ulnar nerve 
and posterior ulnar recurrent artery. One head arises from the inner condyle of 
the humerus by the common tendon; the other, from the inner margin of the 
olecranon by an aponeurosis from the upper two-thirds of the posterior border of 
the ulna, in common with the Flexor profundus digitorum; and from the inter- 
muscular septum between it and the Flexor sublimis digitorum. The fibres ter- 
minate in a tendon which occupies the anterior part of the lower half of the muscle, 
and is inserted into the pisiform bone, some fibres being prolonged to the annular 
ligament, to the unciform bone and base of the metacarpal bone of the little finger. 
The ulnar artery lies on the outer side of the tendon of this muscle, in the lower 
two-thirds of the forearm, the tendon forming a guide in tying the vessel in this 
situation. 
Relations.-By its superficial surface with the deep fascia, with which it is 
intimately connected for a considerable extent; by its deep surface with the Flexor 
sublimis, the Flexor profundus, the Pronator quadratus, and the ulnar vessels and 
nerve; by its outer or radial border with the Palmaris longus above and the ulnar 
vessels and nerve below. 
The Flexor digitorum sublimis imperforatus') is placed beneath the preceding 
muscles, which therefore must be removed in order to bring its attachment into 
view. It is the largest of the muscles of the superficial layer, and arises by three 
heads. One head arises from the internal condyle of the humerus by the common 
tendon, from the internal lateral ligament of the elbow-joint, and from the inter- 
muscular septum common to it and the preceding muscles. The second head arises 
from the inner side of the coronoid process of the ulna, above the ulnar origin of 
the Pronator radii teres (Fig. 208, p. 244). The third head arises from the oblique 
line of the radius, extending from the tubercle to the insertion of the Pronator radii 
teres. The fibres pass vertically downward, forming a broad and thick muscle 
which divides into four tendons about the middle of the forearm; as these tendons 
pass beneath the annular ligament into the palm of the hand, they are arranged in 
pairs, the anterior pair corresponding to the middle and ring fingers, the posterior 
pair to the index and little fingers. The tendons diverge from one another as they 
pass onward, and are finally inserted into the lateral margins of the second pha- 
langes about their middle. After leaving the palm [for the relation of the 
knuckle-joints and the palm, see p. 340] the tendons, accompanied by the deep 
flexor tendons, lie in osseo-aponeurotic canals formed by a strong fibrous band 
which arches across them and is attached on each side to the margins of the pha- 
langes. Opposite the base of the first phalanges each tendon divides, so as to leave 
a fissured interval, through which passes one of the tendons of the Flexor profun- 
dus ; the two portions of the tendon then unite and form a grooved channel into 
which the accompanying deep flexor tendon is received. Finally, they subdivide 
a second time, to be inserted into the sides of the second phalanges about their 
middle (Fig. 323). The tendons, whilst contained in the fibro-osseous canals, are 
connected to the phalanges by slender tendinous filaments, called vincula accessoria 
tendinum, and are invested by a synovial sheath. 
Relations.-In the forearm, by its superficial surface, with the deep fascia and 
all the preceding superficial muscles; by its deep surface with the Flexor profun- 442 
MUSCLES AND FASCINE 
dus digitorum, Flexor longus pollicis, the ulnar vessels and nerve, and the median 
nerve. In the hand its tendons are in relation, in front, with the palmar fascia, 
superficial palmar arch, and the branches of the median nerve; behind with the 
tendons of the deep flexor and the Lumbricales. [For the relations of the tendons 
to the palmar fascia and its prolongations, see p. 450.] 
Anterior Brachial Region. 
Deep Layer. 
Flexor profundus digitorum. 
Flexor longus pollicis. 
Pronator quadratus. 
Dissection.-Divide each of the superficial muscles at its centre [rather, at a different level for 
each muscle, so as to be able the better to identify them later], and turn either end aside; the 
deep layer of muscles, together with the median nerve and ulnar vessels, will then be exposed. 
The Flexor profundus digitorum (perforans) (Fig. SIT) is situated on the 
ulnar side of the forearm, immediately beneath the superficial Flexors. It arises 
from the upper two-thirds of the anterior and inner surfaces of the shaft of the ulna, 
embracing the insertion of the Brachialis anticus above, and extending below to within 
a short distance of the Pronator quadratus. It also arises from a depression on the 
inner side of the coronoid process ; by an aponeurosis from the upper two-thirds of 
the posterior border of the ulna, in common with the Flexor carpi ulnaris ; and from 
the ulnar half of the interosseous membrane. The fibres form a fleshy belly of con- 
siderable size which divides into four tendons: these pass under the annular ligament 
beneath the tendons of the Flexor sublimis. Opposite the first phalanges the ten- 
dons pass between the two slips of the tendons of the Flexor sublimis, and are finally 
inserted into the bases of the last phalanges. The tendon of the index finger is dis- 
tinct ; the rest are connected together by cellular tissue and tendinous slips as far as 
the palm of the hand. [If the fingers be placed on the posterior surface of the fore- 
arm to the inner side of the posterior border of the ulna, and the fingers of the arm 
that is grasped then be alternately flexed to make a fist and relaxed, the contraction 
of the muscular belly of this muscle can be well felt and appreciated.] 
Four small muscles, the Lumbricales, are connected with the tendons of the 
Flexor profundus in the palm. They will be described with the muscles in that 
region. 
Relations.-By its superficial surface, in the forearm, with the Flexor sub- 
limis digitorum, the Flexor carpi ulnaris, the ulnar vessels and nerve, and the 
median nerve, and in the hand with the tendons of the superficial Flexor; by its 
deep surface, in the forearm, with the ulna, the interosseous membrane, the Pro- 
nator quadratus, and in the hand with the Interossei, Adductor pollicis, and deep 
palmar arch ; by its ulnar border with the Flexor carpi ulnaris; by its radial bor- 
der with the Flexor longus pollicis, the anterior interosseous vessels and nerve being 
interposed. 
The Flexor longus pollicis is situated on the radial side of the forearm, lying 
on the same plane as the preceding. It arises from the grooved anterior surface 
of the shaft of the radius, commencing above immediately below the tuberosity 
and oblique line, and extending below to within a short distance of the Pronator 
quadratus. It also arises from the adjacent part of the interosseous membrane, 
and occasionally by a fleshy slip from the base of the coronoid process. The 
fibres pass downward and terminate in a flattened tendon which, passing beneath 
the annular ligament, is then lodged in the interspace between the two heads of the 
Flexor brevis pollicis, and, entering an osseo-aponeurotic canal similar to those 
for the other flexor tendons, is inserted into the base of the last phalanx of the 
thumb. 
Relations.-By its superficial surface with the Flexor sublimis digitorum, 
Flexor carpi radialis, Supinator longus, and radial vessels; by its deep surface 
with the radius, interosseous membrane, and Pronator quadratus; by its ulnar ANTERIOR BRACHIAL REGION. 
443 
border with the Flexor profundus digi- 
torum, from which it is separated by 
the anterior interosseous vessels and 
nerve. 
The Pronator quadratus is a 
small, flat, quadrilateral muscle ex- 
tending transversely across the front 
of the radius and idna above their 
carpal extremities. It arises from the 
oblique line on the lower fourth of the 
anterior surface of the shaft of the ulna 
and the surface of bone immediately 
below it; from the anterior border of 
the ulna; and from a strong aponeur- 
osis which covers the inner third of 
the muscle. The fibres pass horizon- 
tally outward, to be inserted into the 
lower fourth of the anterior surface 
and external border of the shaft of 
the radius. 
Relations.-By its superficial 
surface with the Flexor profundus 
digitorum, the Flexor longus pollicis, 
Flexor carpi radialis, and the radial 
vessels; by its deep surface with the 
radius, ulna, and interosseous mem- 
brane. 
Nerves.-All the muscles of the 
[Fig. 316. 
A Section through the Middle of the Right Forearm 
(Heath, altered from Beraud): 1, anterior interos- 
seous vessels and nerve; 2, radial vessels and 
nerve; 3, Pronator teres; 4, Supinator longus; 5, 
Flexor carpi radialis; 6, Supinator brevis; 7, Flex- 
or sublimis digitorum; 8, Extensores carpi radi- 
alis longior and brevier; 9, Flexor carpi ulnaris; 
10, Extensor ossis metacarpi pollicis; 11, ulnar 
vessels and nerve; 12, Extensor communis digi- 
torum ; 13, Flexor profundus digitorum; 14, Ex- 
tensor carpi ulnaris; 15, median nerve; 16, pos- 
terior interosseous vessels and nerve; 17, Exten- 
sor secundi internodii pollicis.] 
Fig. 317. Front of the Left Forearm, deep muscles. 444 
MUSCLES AND FASCIAE. 
superficial layer are supplied by the median nerve, excepting the Flexor carpi ulna- 
ris, which is supplied by the ulnar. Of the deep layer, the Flexor profundus digi- 
torum is supplied conjointly by the ulnar and by the median through its branch, the 
anterior interosseous nerve, which also supplies the Flexor longus pollicis and Pro- 
nator quadratus. 
Actions.-These muscles act upon the forearm, the wrist, and hand. Those 
acting on the forearm are the Pronator radii teres and Pronator quadratus, which 
rotate the radius upon the ulna, rendering the hand prone; when pronation has 
been fully effected the Pronator radii teres assists the other muscles in flexing the 
forearm. The flexors of the wrist are the Flexor carpi ulnaris and radialis, and the 
flexors of the phalanges are the Flexor sublimis and profundus digitorum, the for- 
mer flexing the second phalanges, and the latter the last. The Flexor longus polli- 
cis flexes the last phalanx of the thumb. The three latter muscles, after flexing 
the phalanges, by continuing their action act upon the wrist, assisting the ordinary 
flexors of this joint; and all those which are attached to the humerus assist in flex- 
ing the forearm upon the arm. The Palmaris longus is a tensor of the palmar fas- 
cia ; when this action has been fully effected it flexes the hand upon the forearm. 
[The bellies of these muscles cannot be well shown separately in the model, though 
the student should observe the influence of making a fist and of flexion of each 
finger on the flexor mass. At the wrist resisted flexion will show to the eye and 
touch, in the middle, the narrow prominent tendon of the Palmaris longus; to its 
radial side, that of the Flexor carpi radialis. Far to the ulnar side the tendon of 
the Flexor carpi ulnaris is well felt in tension when the wrist is flexed and carried 
to the ulnar border. Between the tendons of the Flexor ulnaris and Palmaris 
longus lie the tendons of the finger-flexors, which cannot be made to spring into 
relief because of the anterior annular ligament (see Fig. 315), but on flexing and 
extending the fingers they can be easily felt. 
Of course these muscles, when the hand is fixed, act upon the forearm, and even 
upon the arm, but this is much less marked than is the similar reversed action from 
below of the muscles of the foot.] 
Radial Region (Fig. 318). 
Supinator longus. 
Extensor carpi radialis longior. 
Extensor carpi radialis brevior. 
Dissection.-Divide the integument in the same manner as in the dissection of the anterior 
brachial region, and after having examined the cutaneous vessels and nerves and deep fascia, 
remove all those structures. The muscles will then be exposed. The removal of the fascia will 
be considerably facilitated by detaching it from below upward. Great care should be taken to 
avoid cutting across the tendons of the muscles of the thumb, which cross obliquely the larger 
tendons running down the back of the radius. 
The Supinator longue is the most superficial muscle on the radial side of the 
forearm: it is fleshy for the upper two-thirds of its extent, tendinous below. It 
arises from the upper two-thirds of the external condyloid ridge of the humerus 
and from the external intermuscular septum, being limited above by the musculo- 
spiral groove. The fibres terminate above the middle of the forearm in a flat ten- 
don which is inserted into the outer side of the base of the styloid process of the 
radius. [The belly of this muscle at its origin is ribbon-like, its edge being turned 
externally, but soon it rotates to about a right angle with its first position, thus pro- 
ducing the graceful rounding of the arm over the radial border of the elbow.] 
Relations.-By its superficial surface with the integument and fascia for the 
greater part of its extent: near its insertion it is crossed by the Extensor ossis meta- 
carpi pollicis and the Extensor primi internodii pollicis; by its deep surface with the 
humerus, the Extensor carpi radialis longior and brevior, the insertion of the Pro- 
nator radii teres, and the Supinator brevis; by its inner border above the elbow 
with the Brachialis anticus, the musculo-spiral nerve, and radial recurrent artery, 
and in the forearm with the radial vessels and nerve. RADIAL REGION. 
445 
The Extensor carpi radialis lon- 
gior is placed partly beneath the pre- 
ceding muscle. It arises from the lower 
third of the external condyloid ridge 
of the humerus, and from the external 
intermuscular septum. The fibres ter- 
minate at the upper third of the fore- 
arm in a flat tendon which runs along 
the outer border of the radius, beneath 
the extensor tendons of the thumb ; it 
then passes through a groove common 
to it and the Extensor carpi radialis 
brevior immediately behind the styloid 
process, and is inserted into the base 
of the metacarpal bone of the index 
finger on its radial side. 
Relations.-By its superficial sur- 
face with the Supinator longus and fas- 
cia of the forearm; its outer side is crossed 
obliquely by the extensor tendons of 
the thumb; by its deep surface with the 
elbow-joint, the Extensor carpi radialis 
brevior, and back part of the wrist. 
The Extensor carpi radialis bre- 
vior is shorter, as its name implies, and 
thicker than the preceding muscle, be- 
neath which it is placed. It arises from 
the external condyle of the humerus by 
a tendon common to it and the three fol- 
lowing muscles; from the external lat- 
eral ligament of the elbow-joint; from 
a strong aponeurosis which covers its 
surface; and from the intermuscular 
septa between it and the adjacent mus- 
cles. The fibres terminate about the 
middle of the forearm in a flat tendon 
which is closely connected with that of 
the preceding muscle, accompanies it 
to the wrist, lying in the same groove 
on the posterior surface of the radius; 
passes beneath the annular ligament, 
and, diverging somewhat from its fel- 
low, is inserted into the base of the 
metacarpal bone of the middle finger 
on its radial side. 
The tendons of the two preceding 
muscles pass through the same com- 
partment of the annular ligament, and 
are lubricated by a single synovial mem- 
brane, but are separated from each other 
by a small vertical ridge of bone as they 
lie in the groove at the back of the ra- 
dius. [On forcibly extending the hand 
these tendons can be readily felt just to 
the ulnar side of the Extensor secundi 
internodii pollicis (Fig. 318), and, if the 
motion is resisted, be seen.] 
Fig. 318. Posterior Surface of Forearm, superficial muscles, MUSCLES AND FAS CI AS. 
446 
Relations.-By its superficial surface with the Extensor carpi radialis longior 
and with the Extensor muscles of the thumb, which cross it; by its deep surface 
with the Supinator brevis, tendon of the Pronator radii teres, radius, and wrist- 
joint; by its ulnar border with the Extensor communis digitorum. 
Posterior Brachial Region (Fig. 318). 
Superficial Layer. 
Extensor communis digitorum. 
Extensor minimi digiti. 
Extensor carpi ulnaris. 
Anconeus. 
The Extensor communis digitorum is situated at the back part of the fore- 
arm. It arises from the external condyle of the humerus by the common tendon, 
from the deep fascia, and the intermuscular septa between it and the adjacent mus- 
cles. Just below the middle of the forearm it divides into three tendons, which 
pass, together with the Extensor indicis, through a separate compartment of the 
annular ligament, lubricated by a synovial membrane. The tendons then diverge, 
the innermost one dividing into two; and all, after passing across the back of the 
hand, are inserted into the second and third phalanges of the fingers in the follow- 
ing manner: each tendon becomes narrow and thickened opposite the metacarpo- 
phalangeal articulation, and gives off a thin fasciculus upon each side of the joint 
which serves as the posterior ligament; after having passed the joint it spreads out 
into a broad aponeurosis which covers the whole of the dorsal surface of the first 
phalanx, being reinforced in this situation by the tendons of the Interossei and 
Lumbricales. [Fig. 324, p. 456.] Opposite the first phalangeal j oint this aponeur- 
osis divides into three slips, a middle and two lateral: the former is inserted into 
the base of the second phalanx, and the two lateral, which are continued onward 
along the sides of the second phalanx, unite by their contiguous margins and are 
inserted into the dorsal surface of the last phalanx. As the tendons cross the pha- 
langeal joints they furnish them with posterior ligaments. The tendons of the mid- 
dle, ring, and little fingers are connected together, as they cross the hand, by small 
oblique tendinous slips, or vinculce ; those on each side of the ring finger are strong, 
and bind the tendon of this finger closely to those of the middle and little finger, so 
that it cannot, in general, be freely extended without moving the other two. There 
is also sometimes a thin slip between the tendons of the index and middle fingers. 
The tendons of the index and little fingers also receive, before their division, the 
special extensor tendons belonging to them. [The tendons of this muscle are easily 
seen on the back of the hand.] 
Relations.-By its superficial surface with the fascia of the forearm and hand, 
the posterior annular ligament, and integument; by its deep surface with the Supi- 
nator brevis, the Extensor muscles of the thumb and index finger, the posterior 
interosseous vessels and nerve, the wrist-joint, carpus, metacarpus, and phalanges; 
by its radial border with the Extensor carpi radialis brevier; by its ulnar border 
with the Extensor minimi digiti and Extensor carpi ulnaris. 
The Extensor minimi digiti is a slender muscle placed on the inner side of the 
Extensor communis, with which it is generally connected. It arises from the com- 
mon tendon by a thin tendinous slip, and from the intermuscular septa between it 
and the adjacent muscles. Its tendon runs through a separate compartment in the 
annular ligament behind the inferior radio-ulnar joint, then divides into two as it 
crosses the hand, one slip being united to the common extensor by a cross-piece at 
the metacarpo-phalangeal articulation. Both finally spread into a broad aponeurosis 
which blends with the common extensor to the finger and is inserted into the second 
and third phalanges. The tendon is situated on the ulnar side, and somewhat more 
superficial than the common extensor. 
The Extensor carpi ulnaris is the most superficial muscle on the ulnar side of 
the forearm. It arises from the external condyle of the humerus by the common 
tendon, from the middle third of the posterior border of the ulna below the Anco- POSTERIOR BRACHIAL REGION. 
447 
neus, and from the fascia of the forearm. This muscle terminates in a tendon which 
runs through a groove behind the styloid process of the ulna, passes through a sepa- 
rate compartment in the annular ligament, and is inserted into the ulnar side of the 
base of the metacarpal bone of the little finger. [Its tendon can always be felt by- 
making strong ulnar extension of the hand.] 
Relations.-By its superficial surface with the fascia of the forearm; by its 
deep surface with the ulna and the muscles of the deep layer. 
The Anconeus is a small triangular muscle placed behind and below the elbow- 
joint, and appears to be a continuation of the external portion of the Triceps. It 
arises by a separate tendon from the back part of the outer condyle of the humerus, 
and is inserted into the side of the olecranon and upper fourth of the posterior sur- 
face of the shaft of the ulna; its fibres diverge from their origin, the upper ones 
being directed transversely, the lower obliquely inward. 
Relations.-By its superficial surface with a strong fascia derived from the 
Triceps; by its deep surface with the elbow-joint, the orbicular ligament, the ulna, 
and a small portion of the Supinator brevis. 
Posterior Brachial Region (Fig. 319). 
Deep Layer. 
Supinator brevis. 
Extensor ossis metacarpi pollicis. 
Extensor primi internodii pollicis. 
Extensor secundi internodii pollicis. 
Extensor indicis. 
The Supinator brevis is a broad muscle, of a hollow, cylindrical form, curved 
round the upper third of the radius. It arises from the external condyle of the 
humerus, from the external lateral ligament of the elbow-joint and the orbicular liga- 
ment of the radius, from the ridge on the ulna which runs obliquely downward from 
the posterior extremity of the lesser sigmoid cavity, from the triangular depression 
in front of it, and from a tendinous expansion which covers the surface of the mus- 
cle. The muscle surrounds the upper part of the radius, the upper fibres forming a 
sling-like fasciculus which encircles the neck of the radius above the tuberosity and 
is attached to the back part of its inner surface; the middle fibres are attached to 
the outer edge of the bicipital tuberosity; the lower fibres to the oblique line of the 
radius as low down as the insertion of the Pronator radii teres. This muscle is 
pierced by the posterior interosseous nerve. 
Relations.-By its superficial surface with the superficial Extensor and Supi- 
nator muscles and the radial vessels and nerve; by its deep surface with the elbow- 
joint, the interosseous membrane, and the radius. 
The Extensor ossis metacarpi pollicis is the most external and the largest of 
the deep Extensor muscles: it lies immediately below the Supinator brevis, with 
which it is sometimes united. It arises from the posterior surface of the shaft of 
the ulna below the insertion of the Anconeus, from the interosseous ligament, and 
from the middle third of the posterior surface of the shaft of the radius. Passing 
obliquely downward and outward, it terminates in a tendon which runs through a 
groove on the outer side of the styloid process of the radius, accompanied by the 
tendon of the Extensor primi internodii pollicis, and is inserted into the base of 
the metacarpal bone of the thumb. 
Relations.-By its superficial surface with the Extensor communis digitorum, 
Extensor minimi digiti, and fascia of the forearm, and with the branches of the pos- 
terior interosseous artery and nerve which cross it; by its deep surface with the ulna, 
interosseous membrane, radius, the tendons of the Extensor carpi radialis longior and 
brevior, which it crosses obliquely, and at the outer side of the wrist with the radial 
vessels; by its upper border with the Supinator brevis; by its lower border with the 
Extensor primi internodii pollicis. 
The Extensor primi internodii pollicis, the smallest muscle of this group, lies 
on the inner side of the preceding. It arises from the posterior surface of the shaft 448 
MUSCLES AND FASCIAE. 
of the radius, below the Extensor ossis metacarpi, and from the interosseous mem- 
brane. Its direction is similar to that of the Extensor ossis metacarpi, its tendon 
passing through the same groove on 
the outer side of the styloid process, 
to be inserted into the base of the 
first phalanx of the thumb. 
Relations.-The same as those 
of the Extensor ossis metacarpi pol- 
licis. 
The Extensor secundi inter- 
nodii pollicis is much larger than 
the preceding muscle, the origin of 
which it partly covers in. It arises 
from the posterior surface of the 
shaft of the ulna, below the origin 
of the Extensor ossis metacarpi pol- 
licis, and from the interosseous mem- 
brane. It terminates in a tendon 
which passes through a separate 
compartment in the annular liga- 
ment lying in a narrow oblique 
groove at the back part of the lower 
end of the radius. It then crosses 
obliquely the Extensor tendons of 
the carpus, being separated from the 
other Extensor tendons of the thumb 
by a triangular interval in which the 
radial artery is found ; and is finally 
inserted into the base of the last pha- 
lanx of the thumb. 
[The tendons of these three mus- 
cles are readily seen at the wrist on 
forcibly extending the thumb, the 
cord next the ulna being the Ex- 
tensor secundi internodii; that on 
the radial border is the other two ten- 
dons, the styloid process of the ra- 
dius being between the two cords.] 
Relations.-By its superficial 
surface with the same parts as the 
Extensor ossis metacarpi pollicis; by 
its deep surface with the ulna, inter- 
osseous membrane, radius, the wrist, 
the radial vessels, and metacarpal bone 
of the thumb. 
The Extensor indicis is a nar- 
row, elongated muscle placed on the 
inner side of, and parallel with, the 
preceding. It arises from the pos- 
terior surface of the shaft of the 
ulna, below the origin of the Ex- 
tensor secundi internodii pollicis, and 
from the interosseous membrane. Its 
tendon passes with the Extensor com- 
munis digitorum through the same 
canal in the annular ligament, and subsequently joins the tendon of the Extensor 
communis which belongs to the index finger, opposite the lower end of the corre- 
Fig. 319. 
External Condyle 
Lntemad ICondyle 
extensor 
CARPI ULNAKIS 
Posterior Surface of the Forearm, deep muscles. MUSCLES AND FAS CI MJ OF THE HAND. 
449 
sponding metacarpal bone, lying to the ulnar side of the tendon from the common 
Extensor. It is finally inserted into the second and third phalanges of the index 
finger in the manner already described. 
Relations.-They are similar to those of the preceding muscles. 
Nerves.-The Supinator longus, Extensor carpi radialis longior, and Anconeus 
are supplied by branches from the musculo-spiral nerve; the remaining muscles of 
the radial and posterior brachial regions by the posterior interosseous nerve. 
Actions.-The muscles of the radial and posterior brachial regions, which com- 
prise all the Extensor and Supinator muscles, act upon the forearm, wrist, and hand, 
they are the direct antagonists of the Pronator and Flexor muscles. The Anconeus 
assists the Triceps in extending the forearm. The Supinator longus and brevis are 
the supinators of the forearm and hand, the former muscle more especially acting as 
a supinator when the limb is pronated. When supination has been produced, the 
Supinator longus, if still continuing to act, flexes the forearm. [In fact, flexion 
is its most marked and most important action. Its more advantageous leverage 
gives it three times the proportionate flexor power compared with the Biceps 
(Wight).] The Extensor carpi radialis longior and brevior and Extensor carpi 
ulnaris muscles are the extensors of the wrist; continuing their action, they serve 
to extend the forearm upon the arm; they are the direct antagonists of the 
Flexor carpi radialis and ulnaris. The common Extensor of the fingers, the 
Extensors of the thumb, and the Extensors of the index and little fingers serve to 
extend the phalanges into which they are inserted, and are the direct antagonists 
of the Flexors. [For the correct view of the action of the Extensors and Flexors 
see remarks on the action of the Interossei, p. 457.] By continuing their action 
they assist in extending the forearm. The Extensors of the thumb, in consequence 
of the oblique direction of their tendons, assist in supinating the forearm when the 
thumb has been drawn inward toward the palm [when it is most needed, as in using 
a screw-driver. These muscles also act from below upward, assisting in various 
movements, especially of the forearm, when the hand is fixed. 
The Supinator longus is best shown by endeavoring to lift a heavy table, the 
forearm being flexed at a right angle, supination being at the same time attempted. 
The Anconeus shows w'ell on extreme extension of the forearm.] 
Muscles and Fascle of the Hand. 
Dissection (Fig. 310).-Make a transverse incision across the front of the wrist, and. a second 
across the heads of the metacarpal bones: connect the two by a vertical incision in the middle 
line, and continue it through the centre of the middle finger. The anterior and posterior annu- 
lar ligaments and the palmar fascia should then be dissected. 
The Anterior Annular Ligament is a strong fibrous band which arches over 
the carpus, converting the deep groove on the front of the carpal bones into a canal, 
beneath which pass the flexor tendons of the fingers. It is attached internally to 
the pisiform bone and unciform process of the unciform bone, and externally to the 
tuberosity of the scaphoid and to the inner part of the anterior surface and the ridge 
on the trapezium. It is continuous above with the deep fascia of the forearm, and 
below with the palmar fascia. It is crossed by the ulnar vessels and nerve and the 
cutaneous branches of the median and ulnar nerves. At its outer extremity is the 
tendon of the Flexor carpi radialis, which lies in the groove on the trapezium 
between the attachments of the annular ligament to the bone. It has inserted into 
its upper and inner part the tendon of the Palmaris longus and part of the tendon 
of the Flexor carpi ulnaris, and has arising from it below the small muscles of the 
thumb and little finger. Beneath it pass the tendons of the Flexor sublimis and 
profundus digitorum, the Flexor longus pollicis, and the median nerve. One large 
synovial membrane encloses all these tendons as they pass beneath this ligament. 
It surrounds the tendons for some distance in the forearm, and also in the palm of 
the hand. It presents two prolongations: one is continuous with the sheath of the 
tendon of the Flexor longus pollicis, the other with that of the little finger. [This 450 
MUSCLES AND FASCIAE. 
extension of the synovial sheath on to these two fingers makes felons or other phleg- 
monous inflammations very important, since from these fingers the suppuration may 
readily extend into the palm, and even far up the forearm, by passing under the 
anterior annular ligament, whereas it is shut off from the palm on the other fingers.] 
The Posterior Annular Ligament is a strong fibrous band extending trans- 
versely across the back of the wrist, and consisting of the deep fascia of the back 
of the forearm, strengthened by the addition of some transverse fibres. It forms a 
sheath for the extensor tendons in their 
passage to the fingers, being attached 
internally to the ulna, the cuneiform 
and pisiform bones, and palmar fascia; 
externally, to the margin of the radius, 
and, in its passage across the wrist, to 
the elevated ridges on the posterior 
surface of the radius. It presents six 
compartments for the passage of ten- 
dons, each of which is lined by a sep- 
arate synovial membrane. These are, 
from without inward-1, On the outer 
side of the styloid process for the ten- 
dons of the Extensor ossis metacarpi 
and Extensor primi internodii pollicis ; 
2, behind the styloid process for the 
tendons of the Extensor carpi radialis 
longior and brevior; 3, opposite the outer side of the posterior surface of the radius 
for the tendon of the Extensor secundi internodii pollicis ; 4, to the inner side of the 
latter for the tendons of the Extensor communis digitorum and Extensor indicis; 
5, for the Extensor minimi digiti opposite the interval between the radius and ulna; 
6, for the tendon of the Extensor carpi ulnaris grooving the back of the ulna. The 
synovial membranes lining these sheaths are usually very extensive, reaching from 
above the annular ligament down upon the tendons almost to their insertion. 
The Palmar Fascia [Figs. 321, 322] forms a common sheath which invests the 
muscles of the hand. It consists of a central and two lateral portions. 
The central portion occupies the middle of the palm, is triangular in shape, of 
great strength and thickness, and binds down the tendons in this situation. It is 
narrow above, being attached to the lower margin of the annular ligament, and 
receives the expanded tendon of the Palmaris longus muscle. Below it is broad 
and expanded, and opposite the heads of the metacarpal bones divides into four slips 
for the four fingers. Each slip subdivides into two processes which enclose the ten- 
dons of the Flexor muscles, blending with their sheath, and are attached laterally 
to the fibrous structures on either side of the metacarpo-phalangeal joint: by this 
arrangement four arches are formed, under which the Flexor tendons pass. The 
intervals left in the fascia between the four fibrous slips transmit the digital vessels 
and nerves and the tendons of the Lumbricales. At the points of division of the 
palmar fascia into the slips above mentioned numerous strong transverse fibres bind 
the separate processes together. The palmar fascia is intimately adherent to the 
integument by numerous fibrous bands, and gives origin by its inner margin to the 
Palmaris brevis; it covers the superficial palmar arch, the tendons of the flexor 
muscles, and the branches of the median and ulnar nerves; and on each side it 
gives off a vertical septum which is continuous with the interosseous aponeurosis 
and separates the lateral from the middle palmar group of muscles. 
The lateral portions of the palmar fascia are thin fibrous layers which cover on 
the radial side the muscles of the ball of the thumb, and on the ulnar side the mus- 
cles of the little finger; they are continuous with the dorsal fascia, and in the palm 
with the middle portion of the palmar fascia. 
[The palmar fascia lies under a layer of fibro-fatty tissue, which makes it dif- 
ficult to dissect accurately. Some fibres of the fascia are attached to the skin 
Fig. 320. 
Transverse Section through the Wrist, showing the annu- 
lar ligaments and the canals for the passage of the ten- 
dons. MUSCLES AND FASCIAE OF THE HAND. 
451 
both of the palm and the fingers, and can be best appreciated as they are divided 
in dissection. The four digital tongues begin above the level of the web of the 
thumb, and pass down to be inserted chiefly into the base of the first phalanges 
and the anterior ligaments of the knuckle-joints, while some fibres pass around 
even to the Extensor tendon, others to the sides of the first phalanges, and others 
reach to the second, and possibly even to the third phalanges. A fifth rather 
slender tongue passes to the thumb. The lower border of the fascia is distinctly 
marked, and is situated at the level of the transverse lines in the palm which corre- 
spond to the knuckle-joints (Fig. 261, p. 340.) This is just below the middle of the 
palm. Here there exists a strong band of transverse fibres, some of which also pass 
on to the thumb, but most of them pass to the radial side of the forefinger, under 
[Fig. 321. 
Palmar Fascia, seen from above, showing its longitudinal slips and transverse fibres and attachments to the 
thumb. G are the fibres of Gerdy forming the web of the fingers. The shield-like space to the right of G is 
a piece of skin left in situ. (Dissected by Dr. W. W. Keen; drawn by Dr. J. M. Taylor.)] 
the longitudinal fibres. These fibres to the thumb have been denied or overlooked, 
but I have never failed to find them in the numerous hands I have dissected. Fig. 
322 shows the attachments of the palmar fascia to the metacarpal bones, and the vari- 
ous partitions for the Flexor muscles, and separate ones for the Lumbrical muscles 
with the vessels and nerves. It also again shows the slips going to the thumb, one 
of longitudinal, the other of transverse fibres. 
About an inch below the palmar fascia entirely, at the web of the fingers, exists 
another distinct strong band of transverse fibres, the so-called " fibres of Gerdy " 
(Fig. 321, g). They, in fact, give form and strength to the web of the fingers and 
support to the hand crosswise. Sometimes this band exists so low down as to unite 452 
MUSCLES AND FASCIAE. 
the fingers in such a manner that one cannot be flexed without carrying its neigh- 
bors with it. The fibres pass, some entirely across the hand, others part way, and 
others simply arch over from one finger to another. These last pass down partly 
on the sides of the fingers, joining with the lateral digital fibres of the palmar 
fascia, while others pass directly down the middle line of the first phalanx, chiefly 
in the subcutaneous tissue, and on reaching the base of the second phalanx they 
[Fig. 322. 
Palmar Fascia, seen from beneath. Its attachments to the 
metacarpal bones show well. At a is seen one of the 
Lumbrical muscles; above it are the artery and nerves, 
and in the partitions on each side of it the tendons of 
the two Flexors. The attachments of the fascia to the 
thumb are well shown. (Dissected by Dr. W. W. Keen; 
drawn by Dr. J. M. Taylor.)] 
split astride the Flexor sheath, and are inserted into the sides of the base of the 
second phalanx. 
"Dupuytren's finger-contraction" is produced by contraction of the palmar 
fascia, though it is generally mistaken for contraction of the Flexor tendons. It 
affects preferably the three ulnar fingers, though the forefinger, and occasionally the 
thumb, are involved. It is readily amenable to operation.1] 
Muscles of the Hand. 
The Muscles of the Hand are subdivided into three groups: 1, Those of the 
thumb, which occupy the radial side [thenar eminence] ; 2, those of the little 
finger, which occupy the ulnar side [hypothenar eminence] ; 3, those in the middle 
portion of the palm and between the interosseous spaces. 
Radial Region (Fig. 323). 
Muscles of the Thumb. 
Abductor pollicis. 
Opponens pollicis (or Flexor ossis metacarpi pollicis). 
Flexor brevis pollicis. 
Adductor pollicis. 
The Abductor pollicis is a thin flat muscle placed immediately beneath the 
integument. It arises from the ridge of the os trapezium and annular ligament, 
and, passing outward and dowmward, is inserted by a thin flat tendon into the radial 
side of the base of the first phalanx of the thumb. 
P See a paper by the American Editor in the Reference Handbook of the Medical Sciences, vol. iii. 
p. 159.] RADIAL REGION. 
453 
Relations.-By its superficial surface with the palmar fascia; by its deep sur- 
face with the Opponens pollicis, from which it is separated by a thin aponeurosis. 
Its inner border is separated from the Flexor brevis pollicis by a narrow cellular 
interval. 
The Opponens pollicis [or Flexor ossis metacarpi pollicis] is a small tri- 
Fig. 323. 
Muscles of the Left Hand, palmar surface. 
angular muscle placed beneath the preceding. It arises from the palmar surface of 
the trapezium and annular ligament, passes downward and outward, and is inserted 
into the whole length of the metacarpal bone of the thumb on its radial side. 454 
MUSCLES AND FASCIAE. 
Relations.-By its superficial surface with the Abductor pollicis; by its deep 
surface with the trapezio-metacarpal articulation; by its inner border with the 
Flexor brevis pollicis. 
The Flexor brevis pollicis is much larger than either of the two preceding 
muscles beneath which it is placed. It consists of two portions, in the interval 
between which lies the tendon of the Flexor longus pollicis. The anterior and 
more superficial portion arises from the trapezium and outer two-thirds of the annu- 
lar ligament; the deeper portion, from the trapezoid, os magnum, bases of the second 
and third metacarpal bones, and sheath of the tendon of the Flexor carpi radialis. 
The two portions are united by a bundle of fibres which pass behind the long flexor 
and are inserted one on either side of the base of the first phalanx of the thumb, 
the outer portion being joined with the Abductor, and the inner with the Adductor. 
A sesamoid bone is developed in each tendon as it passes across the metacarpo-pha- 
langeal joint. 
Relations.-By its superficial surface with the palmar fascia; by its deep sur- 
face with the Adductor pollicis and tendon of the Flexor carpi radialis; by its 
external .surface with the Opponens pollicis; by its internal surface with the Ad- 
ductor pollicis. 
The Adductor pollicis (Figs. 317 and 323) is the most deeply seated of this group 
of muscles. It is of a triangular form, arising by its broad base from the lower two- 
thirds of the metacarpal bone of the middle finger on its palmar surface; the fibres, 
proceeding outward, converge, to be inserted, with the inner tendon of the Flexor 
brevis pollicis, into the ulnar side of the base of the first phalanx of the thumb and 
into the internal sesamoid bone. 
[Duchenne1 has recalled attention to the fact that the Abductor, Adductor, and 
Short Flexor of the thumb all have aponeurotic expansions at their insertions, con- 
necting them with the tendon of the Extensor longus pollicis. They use this tendon 
as an indirect insertion, as well as their own direct insertion, the object of the 
arrangement being to produce flexion of the first phalanx and extension of the sec- 
ond, both at the same time. This anatomical arrangement and physiological use of 
the thumb find their analogue in the fingers (p. 457), as we might indeed expect, for 
the Ab- and Ad-ductor pollicis are the analogues of the Interosseous muscles.] 
Relations.-By its superficial surface with the Flexor brevis pollicis, the ten- 
dons of the Flexor profundus, and the Lumbricales. Its deep surface covers the 
first two interosseous spaces, from which it is separated by a strong aponeurosis. 
Nerves.-The Abductor, Opponens, and outer head of the Flexor brevis pol- 
licis are supplied by the median nerve: the inner head of the Flexor brevis and 
the Adductor pollicis, by the ulnar nerve. 
Actions.-The actions of the muscles of the thumb are almost sufficiently indi- 
cated by their names. This segment of the hand is provided with three Extensors 
-an Extensor of the metacarpal bone, an Extensor of the first, and an Extensor 
of the second phalanx ; these occupy the dorsal surface of the forearm and hand. 
There are also three Flexors on the palmar surface-a Flexor of the metacarpal 
bone, the Flexor ossis metacarpi (Opponens pollicis), the Flexor brevis pollicis, and 
the Flexor longus pollicis. There is also an Abductor and an Adductor. These 
muscles give to the thumb its extensive range of motion. 
Ulnar Region (Fig. 323). 
Muscles of the Little Finger. 
Palmaris brevis'. 
Abductor minimi digiti. 
Flexor brevis minimi digiti. 
Opponens minimi digiti 
(or Flexor ossis metacarpi minimi digiti). 
The Palmaris brevis is a thin quadrilateral muscle placed beneath the integu- 
ment on the ulnar side of the hand. It arises by tendinous fasciculi from the 
f1 Physiol, des Mouvements, Paris, 1867, p. 299.] MIDDLE PALMAR REGION. 
455 
annular ligament and palmar fascia; the fleshy fibres pass horizontally inward to 
be inserted into the skin on the inner border of the palm of the hand. [It can 
generally be very well shown by electricity, and the same means will differentiate 
admirably most of the muscles of the hand.] 
Relations.-By its superficial surface with the integument, to which it is inti- 
mately adherent, especially by its inner extremity; by its deep surface with the 
inner portion of the palmar fascia, which separates it from the ulnar vessels and 
nerve and from the muscles of the ulnar side of the hand. 
The Abductor minimi digiti is situated on the ulnar border of the palm of the 
hand. It arises from the pisiform bone and from an expansion of the tendon of the 
Flexor carpi ulnaris, and terminates in a flat tendon which is inserted into the ulnar 
side of the base of the first phalanx of the little finger, sending an offset to the 
extensor tendon on the back of the phalanx. 
Relations.-By its superficial surface with the inner portion of the palmar 
fascia and the Palmaris brevis; by its deep surface with the Flexor ossis meta- 
carpi ; by its inner border with the Flexor brevis minimi digiti. 
The Flexor brevis minimi digiti lies on the same plane as the preceding mus- 
cle, on its radial side. It arises from the tip of the unciform process of the unci- 
form bone and anterior surface of the annular ligament, and is inserted into the 
base of the first phalanx of the little finger with the preceding. It is separated 
from the Abductor at its origin by the deep branches of the ulnar artery and 
nerve. This muscle is sometimes wanting; the Abductor is then usually of large 
size. 
Relations.-By its superficial surface with the internal portion of the palmar 
fascia and the Palmaris brevis; by its deep surface with the Opponens. 
The Opponens minimi digiti [or Flexor ossis metacarpi minimi digiti] 
(Fig. 317, p. 443) is of a triangular form and placed immediately beneath the pre- 
ceding muscles. It arises from the unciform process of the unciform bone and con- 
tiguous portion of the annular ligament; its fibres pass downward and inward to 
be inserted into the whole length of the metacarpal bone of the little finger along 
its ulnar margin. 
Relations.-By its superficial surface with the Flexor brevis and Abductor 
minimi digiti; by its deep surface with the Interosseous muscles in the fourth meta- 
carpal space, the metacarpal bone, and the Flexor tendons of the little finger. 
Nerves.-All the muscles of this group are supplied by the ulnar nerve. 
Actions.-The actions of the muscles of the little finger are expressed in their 
names. The Palmaris brevis corrugates the skin on the inner side of the palm of 
the hand. 
Middle Palmar Region. 
Lumbricales. 
Interossei dorsales. 
Interossei palmares. 
The Lumbricales (Fig. 323) are four small fleshy fasciculi, accessories to the 
deep Flexor muscle. They arise by fleshy fibres from the tendons of the deep 
Flexor: the first and second from the radial side and palmar surface of the tendons 
of the index and middle fingers; the third from the contiguous sides of the tendons 
of the middle and ring fingers; and the fourth from the contiguous sides of the ten- 
dons of the ring and little fingers. They pass forward to the radial side of the cor- 
responding fingers, and opposite the metacarpo-phalangeal articulation each tendon 
terminates in a broad aponeurosis which is inserted into the tendinous expansion from 
the Extensor communis digitorum covering the dorsal aspect of each finger. 
The Interosseous muscles are so named from occupying the intervals between 
the metacarpal bones. They are divided into two sets, a dorsal and palmar: the 
former are four in number, one in each metacarpal space; the latter, three in num- 
ber, lie upon the metacarpal bones. 
The Dorsal interossei are four in number, larger than the palmar, and occupy 
the intervals between the metacarpal bones. They are bipenniform muscles, arising 456 
MUSCLES AND FASCIAE. 
by two heads from the adjacent sides of the metacarpal bones, but more extensively 
from that side of the metacarpal bone which corresponds to the side of the finger in 
W'hich the muscle is inserted. They are inserted into the base of the first phalanges 
and into the aponeurosis of the common Extensor tendon. Between the double 
[Fig. 324. 
Ring Finger of the Right Hand, with its Adductor Interosseous Muscle: a, one belly of the Interosseous, attached 
at b to the first phalanx; c, the other belly of the Interosseous, attached by d, d, its tendon, to the posterior 
surface of the second and third phalanges, and joined to e, e, the tendon of the Extensor communis 
(Duchenne).] 
origin of each of these muscles is a narrow triangular interval through which passes 
a perforating branch from the deep palmar arch. 
The First Dorsal interosseous muscle, or Abductor indicis, is larger than 
the others. It is flat, triangular in form, and arises by two heads, separated by a 
Fig. 325. 
Fig. 326. 
The Dorsal Interossei of Left Hand. 
The Palmar Interossei of Left Hand. 
fibrous arch for the passage of the radial artery from the dorsum to the palm of the 
hand. The outer head arises from the upper half of the ulnar border of the first 
metacarpal bone; the inner head, from almost the entire length of the radial border 
of the second metacarpal bone; the tendon is inserted into the radial side of the SURGICAL ANATOMY. 
457 
index finger. The second and third Dorsal interossei are inserted into the middle 
finger, the former into its radial, the latter into its ulnar side. The fourth is inserted 
into the ulnar side of the ring finger. 
The Palmar interossei, three in number, are smaller than the Dorsal, and placed 
upon the palmar surface of the metacarpal bones, rather than between them. They 
arise from the entire length of the metacarpal bone of one finger, and are inserted 
into the side of the base of the first phalanx and the aponeurotic expansion of the 
common Extensor tendon of the same finger. 
The first arises from the ulnar side of the second metacarpal bone, and is inserted 
into the same side of the index finger. The second arises from the radial side of the 
fourth metacarpal bone, and is inserted into the same side of the ring finger. The 
third arises from the radial side of the fifth metacarpal bone, and is inserted into the 
same side of the little finger. From this account it may be seen that each finger is 
provided with two Interossei muscles, with the exception of the little finger, in which 
the Abductor muscle takes the place of one of the pair. 
Nerves.-The two outer Lumbricales are supplied by the median nerve, the rest 
of the muscles of this group by the ulnar. 
Actions.-The Dorsal interossei muscles abduct the fingers from an imaginary 
line drawn longitudinally through the centre of the middle finger, and the Palmar 
interossei adduct the fingers toward that line. They usually assist the Extensor 
muscles, but when the fingers are slightly bent they assist in flexing them. The 
action of the Lumbricales and Internal or Dorsal interossei is said by Hunter to be 
to flex the first phalanges and extend the last two ( Works by Palmer, iv. 237); and 
Cleland supports this {Journ. of Anat. and Phys., Old Series, i. 85). M. Duchenne 
gives a different account of the mechanism of the extension of the fingers, and of 
the action of the Interossei muscles, from that usually accepted. According to him, 
the Extensor communis digitorum acts almost entirely on the first phalanges, exten- 
sion of the second and third phalanges being effected by the Interossei muscles, 
which also act to a certain extent as flexors of the first phalanges. This action of 
the Interossei is additional to their action in abduction and adduction (Physiologic 
des Mouvements, pp. 261-298).1 
[There is no question of the correctness of Hunter's and Duchenne's view. 
Electricity, many cases of paralysis of the ulnar nerve and of lead palsy which I 
have seen, all point the same way. To sum up: The first phalanges are flexed by 
the Interossei and Lumbricales, and extended by the Extensor communis; the last 
two phalanges are flexed by the Flexor sublimis and Flexor profundus respectively, 
and extended by the Extensor communis to a moderate degree, but chiefly by the 
Interossei and Lumbricales.] 
SURGICAL ANATOMY. 
The student, having completed the dissection of the muscles of the upper extremity, should 
consider the effects likely to be produced by the action of the various muscles in fracture of the 
bones. 
In considering the actions of the various muscles upon fractures of the upper extremity I 
have selected the most common forms of injury both for illustration and description. 
Fracture of the clavicle is an exceedingly common accident, and is usually caused by indi- 
rect violence, as a fall upon the shoulder [or hand] ; it occasionally, however, occurs from direct 
force. Its more usual situation is just external to the centre of the bone, but it may occur at 
the sternal or acromial end. 
Fracture of the middle of the clavicle (Fig. 327) is always attended with considerable displace- 
ment, the outer fragment being drawn downward, forward, and inward; the inner fragment 
slightly upward. The outer fragment is drawn down by the weight of the arm and the action 
1 M. Duchenne's view of the action of these muscles certainly derives support from the phenomena 
observed in lead palsy and from the results of galvanizing the common Extensor and the Interossei, 
as Dr. W. Ogle has been kind enough to point out to me. Thus also in a case related by Mr. 
Hutchinson, in which the ulnar nerve had been divided below the part from which the Extensor 
communis was supplied (and therefore the Interossei were paralyzed while the Extensor acted), " the 
first phalanges were bent backward on the metacarpal bones" (extended), "while the fingers were 
curved into the palm" (second and third phalanges flexed) {London Hospital Reports, vol. iii. p. 307). 458 
MUSCLES AND FASCIAE. 
of the Deltoid, and forward and inward by the Pectoralis minor and Subclavius muscles; the 
inner fragment is slightly raised by the Sterno-cleido-mas- 
toid, but only to a very limited extent, as the attachment 
of the costo-clavicular ligament and Pectoralis major be- 
low and in front would prevent any very great displace- 
ment upward. The causes of displacement having been 
ascertained, it is easy to apply the appropriate treatment. 
The outer fragment is to be drawn outward, and, together 
with the scapula, raised upward to a level with the inner 
fragment, and retained in that position. 
In fracture of the acromial end of the clavicle, be- 
tween the conoid and trapezoid ligaments, only slight 
displacement occurs, as these ligaments, from their ob- 
lique insertion, serve to hold both portions of the bone 
in apposition. Fracture also of the sternal end, inter- 
nal to the costo-clavicular ligament, is attended with 
only slight displacement, this ligament serving to retain 
the fragments in close apposition. 
Fracture of the acromion process usually arises from 
violence applied to the upper and outer part of the 
shoulder ; it is generally known by the rotundity of the 
shoulder being lost from the Deltoid drawing the frac- 
tured portion downward and forward ; and the displace- 
ment may easily be discovered by tracing the margin of 
the clavicle outward, when the fragment will be found 
resting on the front and upper part of the head of the 
humerus. In order to relax the anterior and outer 
fibres of the Deltoid (the opposing muscle), the arm should 
be drawn forward across the chest and the elbow well 
raised, so that the head of the bone may press the acro- 
mion process upward and retain it in its position. 
Fracture of the coracoid process is an extremely rare accident, and is usually caused by a 
sharp blow on the point of the shoulder. Displacement is here produced by the combined 
actions of the Pectoralis minor, short head of the Biceps, and Coraco-brachialis, the former mus- 
cle drawing the fragment inward, and the latter directly downward, the amount of displacement 
being limited by the connection of this process to the acromion by means of the coraco-aoromial 
ligament. In order to relax these muscles and replace the fragments in close apposition, the 
forearm should be flexed, so as to relax the Biceps, and the arm drawn forward and inward 
across the chest, so as to relax the Coraco-brachialis ; the humerus should then be pushed up- 
ward against the coraco-acromial ligament, and the arm retained in that position. 
Fracture of the anatomical neck of the humerus within the capsular ligament is a rare acci- 
dent, attended with very slight displacement, an impaired condition of the motions of the joint, 
and crepitus. 
Fracture of the surgical neck (Fig. 328) is very common, is attended with considerable dis- 
placement, and its appearances correspond somewhat with those of dislocation of the head of the 
humerus into the axilla. The upper fragment is slightly elevated 
under the coraco-acromial ligament by the muscles attached 
to the greater and lesser tuberosities; the lower fragment is 
drawn inward by the Pectoralis major, Latissimus dorsi, and 
Teres major, and the humerus is thrown obliquely outward 
from the side by the Deltoid, and occasionally elevated so as 
to project beneath and in front of the coracoid process. The 
deformity is reduced by fixing the shoulder and drawing the 
arm outward and downward. To counteract the opposing 
muscles and to keep the fragments in position, the arm should 
be drawn from the side, and pasteboard splints applied on its 
four sides; a large conical-shaped pad should be placed in 
the axilla, with the base turned upward and the elbow 
approximated to the side, and retained there by a broad roller 
passed round the chest; the forearm should then be flexed, 
and the hand supported in a sling, care being taken not to 
raise the elbow, otherwise the lower fragment may be dis- 
placed upward. 
In fracture of the shaft of the humerus below the inser- 
tion of the Pectoralis major, Latissimus dorsi, and Teres 
major, and above the insertion of the Deltoid, there is also 
considerable deformity, the upper fragment being drawn 
inward by the first-mentioned muscles, and the lower frag- 
ment upward and outward by the Deltoid, producing short- 
ening of the limb and a considerable prominence at the seat 
of fracture from the fractured ends of the bone riding over each other, especially if the frac- 
Fig. 327. 
Fracture of the Middle of the Clavicle. 
Fig. 328. 
Fracture of the Surgical Neck of the 
Humerus. SURGICAL ANATOMY. 
459 
ture takes place in an oblique direction. The fragments may be brought into apposition by 
extension from the elbow, and retained in that position by adopting the same means as in the 
preceding injury. 
In fractures of the shaft of the humerus immediately below the insertion of the Deltoid the 
amount of deformity depends greatly upon the direction of the fracture. If the fracture occurs 
in a transverse direction, only slight displacement occurs, the upper fragment being drawn a 
little forward ■ but in oblique fracture the combined actions of the Biceps and Brachialis anticus 
muscles in front and the Triceps behind draw upward the lower fragment, causing it to glide 
over the upper fragment, either backward or forward according to the direction of the fracture. 
Simple extension reduces the deformity, and the application of splints on the four sides of the 
arm will retain the fragments in apposition. Care should be taken not to raise the elbow, but 
the forearm and hand may be supported in a sling. 
Fracture of the humerus (Fig. 329) immediately above the condyles deserves very attentive 
consideration, as the general appearances correspond somewhat with those produced by separa- 
tion of the epiphysis of the humerus and with those of 
dislocation of the radius and ulna backward. If the direc- 
tion of the fracture is oblique from above, downward, and 
forward, the lower fragment is drawn upward and back- 
ward by the Brachialis anticus and Biceps in front and the 
Triceps behind. This injury may be diagnosticated from 
dislocation by the increased mobility in fracture, the exist- 
ence of crepitus, and the fact of the deformity being reme- 
died by extension, on the discontinuance of which it is 
reproduced. [In fracture there will be shortening from 
the acromion to the external condyle, while the measure- 
ments from the olecranon to the condyles will be un- 
changed. In dislocation the measurements from the ole- 
cranon to the condyles will be changed, while that from 
the acromion to the external condyle will be unchanged.] 
The age of the patient is of importance in distinguishing 
this form of injury from separation of the epiphysis. If 
fracture occurs in the opposite direction to that shown in 
the accompanying figure, the lower* fragment is drawn up- 
ward and forward, causing a considerable prominence in 
front; and the upper fragment projects backward beneath 
the tendon of the Triceps muscle. 
Fracture of the coronoid process of the ulna is an acci- 
dent of rare occurrence, and is usually caused by violent 
action of the Brachialis anticus muscle. The amount of 
displacement varies according to the extent of the fracture. 
If the tip of the process only is broken off, the fragment is 
drawn upward by the Brachialis anticus on a level with the coronoid depression of the humerus, 
and the power of flexion is partially lost. If the process is broken off near its root, the frag- 
ment is still displaced by the same muscle; 
at the same time, on extending the forearm, 
partial dislocation backward of the ulna oc- 
curs from the action of the Triceps muscle. 
The appropriate treatment would be to relax 
the Brachialis anticus by flexing the forearm, 
and to retain the fragments in apposition by 
keeping the arm in this position. Union is 
generally ligamentous. 
Fracture of the olecranon process (Fig. 330) 
is a more frequent accident, and is caused 
either by violent action of the Triceps muscle 
or by a fall or blow upon the point of the 
elbow. The detached fragment is displaced 
upward from half an inch to two inches by 
the action of the Triceps muscle; the promi- 
nence of the elbow is consequently lost, and a 
deep hollow is felt at the back part of the 
joint, which is much increased on flexing the 
limb. The patient at the same time loses, 
more or less, the power of extending the fore- 
arm. The treatment consists in relaxing the 
Triceps by extending the limb, and retaining it in the extended position by means of a long 
straight splint applied to the front of the arm: the fragments are thus brought into close appo- 
sition, and may be further approximated by drawing down the upper fragment. Union is 
generally ligamentous. 
Fracture of the neck of the radius is an exceedingly rare accident, and is generally caused by 
direct violence. Its diagnosis is somewhat obscure on account of the slight deformity visible, the 
Fig. 329- 
Fracture of the Humerus above the 
Condyles. 
Fig. 330. 
Fracture of the Olecranon. 460 
MUSCLES AND FASCIAE. 
injured part being surrounded by a large number of muscles ; but the movements of pronation 
and supination are entirely lost. The upper fragment is drawn outward by the Supinator brevis, 
its extent of displacement being limited by the attachment of the orbicular ligament. The lower 
fragment is drawn forward and slightly upward by the Biceps, and inward by the Pronator radii 
teres, its displacement forward and upward being counteracted in some degree by the Supinator 
brevis. The treatment essentially consists in relaxing the Biceps, Supinator brevis, and Pronator 
radii teres muscles by flexing the forearm and placing it in a position midway between prona- 
tion and supination, extension having been previously made so as to bring the parts in apposition. 
Fracture of the radius is [far] more common than fracture of the ulna, on account of the con- 
nection of the former bone with the wrist. Fracture of the shaft of the radius (Fig. 331) near its 
centre may occur from direct violence, but 
more frequently from a fall forward, the 
weight of the body being received on the wrist 
and hand. The upper fragment is drawn for- 
ward by the Biceps and inward by the Pronator 
radii teres, holding a position midway between 
pronation and supination, and a degree of ful- 
ness in the upper half of the forearm is thus 
produced: the lower fragment is drawn back- 
ward and inward toward the ulna by the Pro- 
nator quadratus, and thrown into a state of 
pronation by the same muscle; at the same 
time, the Supinator longus, by elevating the 
styloid process, into which it is inserted, will 
serve to displace the upper end of the lower fragment still more toward the ulna. In order to 
relax the opposing muscles, the forearm should be bent and the limb placed in a position mid- 
way between pronation and supination; the fracture is then easily reduced by extension from 
the wrist and elbow: well-padded splints should then be applied on both sides of the forearm 
from the elbow to the wrist; the hand, being allowed to fall, will by its own weight counteract 
the action of the Pronator quadratus and Supinator longus, and elevate the lower fragment to 
the level of the upper one. 
Fracture of the shaft of the ulna is not a common accident: it is usually caused by direct vio- 
lence. The more protected position of the ulna on the inner side of the limb, the greater strength 
of its shaft, and its indirect connection with the wrist render it less liable to injury than the 
radius. The fracture usually occurs a little below the middle, which is the weakest part of the 
bone. The upper fragment retains its usual position, but the lower fragment is-drawn outward 
toward the radius by the Pronator quadratus, producing a well-marked depression at the seat of 
fracture and some fulness on the dorsal and palmar surfaces of the forearm. The fracture is 
easily reduced by extension from the wrist and forearm. The forearm should be flexed, and 
placed in a position midway between pronation and supination, and well-padded splints applied 
from the elbow to the ends of the fingers. 
Fracture of the shafts of the ulna and radius together is not a very common accident; it may 
arise from a direct blow or from indirect violence. The lower fragments are drawn upward, 
sometimes forward, sometimes backward, according to the direction of the fracture, by the com- 
bined actions of the Flexor and Extensor muscles, producing a degree of fulness on the dorsal or 
palmar surfaces of the forearm ; at the same time the two [lower] fragments are drawn into con- 
tact by the Pronator quadratus, the radius in a state of pronation: the upper fragment of the 
radius is drawn forward and inward by the Biceps and Pronator radii teres to a plane anterior 
Fig. 331. 
Fracture of the Shaft of the Radius. 
Fig. 332. 
Fracture of the Lower End of the Radius. 
to that of the ulna; the upper portion of the ulna is slightly flexed by the Brachialis anticus. 
The fracture may be reduced by extension from the wrist and elbow, and the forearm should be 
placed in the same position as in fracture of the ulna. 
In the treatment of all cases of fracture of the bones of the forearm the greatest care is requi- 
site to prevent the ends of the bones from being drawn inward toward the interosseous space: if 
this point is not carefully attended to, the radius and ulna may become ankylosed and the move- OF THE LOWER EXTREMITY. 
461 
ments of pronation and supination entirely lost. To obviate this, the splints applied to the limb 
should be well padded, so as to press the muscles down into their normal situation in the inter- 
osseous space, and thus prevent the approximation of the fragments [and, as a rule, the forearm 
should be midway between pro- and supi-nation, in which position the radius and ulna are sepa- 
rated by the widest interval]. 
Fracture of the lower end of the radius (Fig. 332) is usually called Colles' fracture, from the 
name of the eminent Dublin surgeon who first accurately described it. It is generally produced 
by the patient falling upon the hand, which receives the entire weight of the body [and fractures 
the bone by "cross-breaking strain" through the strong anterior radio-carpal ligament]. This 
fracture usually takes place from half an inch to an inch above the articular surface if it occurs in 
the adult, but in the child, before the age of sixteen, it is more frequently a separation of the 
•epiphysis from the diaphysis. The displacement which is produced is very considerable, and bears 
some resemblance to dislocation of the carpus backward [a very rare accident], from which it 
should be carefully distinguished. The lower fragment is drawn upward and backward behind 
the upper fragment by the combined actions of the Supinator longus and the flexors and the 
extensors of the thumb and carpus, producing a well-marked prominence on the back of the 
wrist, with a deep depression above it. The upper fragment projects forward, often lacerating 
the substance of the Pronator quadratus, and is drawn by this muscle into close contact with the 
lower end of the ulna, causing a projection on the anterior surface of the forearm immediately 
above the carpus, from the flexor tendons being thrust forward. This fracture may be distin- 
guished from dislocation by the deformity being removed on making sufficient extension, when 
crepitus may be occasionally detected ; at the same time, on extension being discontinued, the 
parts immediately resume their deformed appearance. The age of the patient will also assist in 
determining whether the injury is fracture or separation of the epiphysis. The treatment con- 
sists in flexing the forearm and making powerful extension from the wrist and elbow, depressing 
at the same time the radial side of the hand, and retaining the parts in that position by well- 
padded pistol-shaped splints. [The better treatment is, first, by complete extension of the lower 
fragmept to disengage it; next, by simultaneous traction and flexion to reduce it; and then to 
apply a splint, not pistol-shaped, but adapted to the forearm and the flexed hand, such as one 
made of plaster or Levis' copper splint.] 
MUSCLES AND FASCLZE OF THE LOWER EXTREMITY. 
The Muscles of the Lower Extremity are subdivided into groups, corresponding 
with the different regions of the limb. 
[The different uses of the upper and lower extremities produce a striking differ- 
ence in the arrangement and action of their muscles and joints. In the arm, in 
which prehension is the chief function, all the flexors are placed anteriorly, and 
flexion of all the joints is in the same direction. In the leg, which is for station and 
locomotion, the arrangement is one of alternation. Thus, the flexors of the hip-joint 
are in front, the flexors of the knee behind; those of the ankle in front, those of the 
toes posteriorly; the joints, of course, being similarly arranged. Were this not so, 
stooping and similar vertical motions would be impossible, and station would be at 
least uncertain.] 
Iliac Region. 
Psoas magnus. 
Psoas parvus. 
Iliacus. 
Pectineus. 
Adductor longus. 
Adductor brevis. 
Adductor magnus. 
Thigh. 
Anterior Femoral Region. 
Tensor vaginae femoris. 
Sartorius. 
Rectus. 
Vastus externus. 
Vastus internus. 
Crureus. 
Subcrureus. 
Internal Femoral Region. 
Gracilis. 
Hip. 
G-luteal Region. 
Gluteus maximus. 
Gluteus meclius. 
Gluteus minimus. 
Pyriformis. 
Gemellus superior. 
Obturator internus. 
Gemellus inferior. 
Obturator externus. 
Quadratus femoris. 462 
MUSCLES AND FAS CI Mi. 
Posterior Femoral Region. 
Biceps. 
Semitendinosus. 
Semimembranosus. 
Foot. 
Dorsal Region. 
Extensor brevis digitorum. 
Plantar Region. 
First Layer. 
Abductor pollicis. 
Flexor brevis digitorum. 
Abductor minimi digiti. 
Second Layer. 
Flexor accessorius. 
Lumbricales. 
Third Layer. 
Flexor brevis pollicis. 
Adductor pollicis. 
Flexor brevis minimi digiti. 
Transversus pedis. , 
Fourth Layer. 
The Interossei. 
Leg. 
Anterior Tibio-fibular Region. 
Tibialis anticus. 
Extensor longus digitorum. 
Extensor proprius pollicis. 
Peroneus tertius. 
Posterior Tibio-fibular Region. 
Superficial Layer. 
Gastrocnemius. 
Plantaris. 
Soleus. 
Deep Layer. 
Popliteus. 
Flexor longus pollicis. 
Flexor longus digitorum. 
Tibialis posticus. 
Fibular Region. 
Peroneus longus. 
Peroneus brevis. 
Iliac Region. 
Psoas magnus. 
Psoas parvus. 
Iliacus. 
Dissection.-No detailed description is required for the dissection of these muscles. On the 
removal of the viscera from the abdomen they are exposed, covered by the peritoneum and a 
thin layer of fascia, the iliac fascia. 
The Iliac Fascia1 is the aponeurotic layer which lines the back part of the 
abdominal cavity and covers the Psoas and Iliacus muscles throughout their whole 
extent. It is thin above, and becomes gradually thicker below as it approaches the 
femoral arch. 
The portion investing the Psoas is attached above to the ligamentum arcuatum 
internum, internally to the sacrum, and by a series of arched processes to the inter- 
vertebral substances and prominent margins of the bodies of the vertebrae, the 
intervals so left, opposite the constricted portions of the bodies, transmitting the 
lumbar arteries and filaments of the sympathetic nerve. Externally, this portion, 
of the iliac fascia is continuous with the anterior lamella of the posterior aponeur- 
osis of the Transversalis muscle or lumbar fascia. (See p. 416.) 
The portion investing the Iliacus is connected externally to the whole length of 
the inner border of the crest of the ilium, and internally to the brim of the true 
pelvis, where it is continuous with the periosteum and receives the tendon of inser- 
tion of the Psoas parvus when that muscle exists. External to the femoral vessels 
this fascia is intimately connected with Poupart's ligament, and is continuous with 
the fascia transversalis; but as the femoral vessels pass down into the thigh it is pro- 
longed down behind them, and, passing under Poupart's ligament, it forms the pos- 
terior wall of the femoral sheath and rests on the pubic portion of the fascia lata, 
with which it is connected. [The femoral sheath is completed by a prolongation 
of the Transversalis fascia downward in front of the vessels.] Internal to the 
femoral vessels the iliac fascia, where it is continuous with the pubic portion of the 
1 The student must not confound this fascia with the iliac portion of the fascia lata. (See p. 466.) ILIAC REGION. 
463 
fascia lata, sends a strong process backward be- 
tween the psoas and pectineus to be attached to 
the ilio-pectineal eminence and the capsule of 
the hip-joint. The external iliac vessels lie in 
front of the iliac fascia, but all the branches of 
the lumbar plexus behind it; it is separated from 
the peritoneum by a quantity of loose areolar tis- 
sue. In abscess accompanying caries of the lower 
part of the spine the matter makes its way to the 
femoral arch, distending the sheath of the Psoas 
[and therefore usually " points " below Poupart's 
Fig. 333. 
1. Dissection 
of 
FEMORAL HERNIA, 
&, 
SCARPAS TRIANGLE 
Z . FRONT of THIGH 
3 . LEG 
ff. . DORSUMjf FOOT 
ligament] ; and when it accumulates in consider- 
able quantity this muscle becomes absorbed and 
the nervous cords contained in it are dissected out, 
and are exposed in the cavity of the abscess ; the 
femoral vessels, however, remain intact, and the 
peritoneum seldom becomes implicated. 
Remove this fascia, and the muscles of the 
iliac region will be exposed. 
The Psoas magnus (Fig- 334) is a long fusi- 
form muscle placed on the side of the lumbar re- 
gion of the spine and margin of the pelvis. It 
Dissection of Lower Extremity, front view. 
FlG'334, MFemorai Regions0 and Anterior 464 
MUSCLES AND FASCIAE. 
arises from the sides of the bodies, from the corresponding intervertebral substances, 
and from the front of the bases of the transverse processes of the last dorsal and all 
the lumbar vertebrae. The muscle is connected to the bodies of the vertebrae by five 
slips: each slip is attached to the upper and lower margins of two vertebrae and to 
the intervertebral substance between them, the slips themselves being connected by 
the tendinous arches which extend across the constricted part of the bodies, and 
beneath which pass the lumbar arteries and sympathetic nerves. These tendinous 
arches also give origin to muscular fibres, and protect the blood-vessels and nerves 
from pressure during the action of the muscle. The first slip is attached to the con- 
tiguous margins of the last dorsal and first lumbar vertebrae, the last to the contiguous 
margins of the fourth and fifth lumbar and to the intervertebral substance. From 
these points the muscle passes down across the brim of the pelvis, and, diminishing 
gradually in size, passes beneath Poupart's ligament and terminates in a tendon, 
which, after receiving the fibres of the Iliacus, is inserted into the lesser trochanter 
of the femur. 
Relations in the Lumbar Region.-By its anterior surface, which is placed 
behind the peritoneum, with the iliac fascia, the ligamentum arcuatum internum, 
the kidney, Psoas parvus, renal vessels, ureter, spermatic vessels, genito-crural nerve, 
the colon, and along its pelvic border with the common and external iliac artery and 
vein; by its posterior surface with the transverse processes of the lumbar vertebrae 
and the Quadratus lumborum, from which it is separated by the anterior lamella of 
the aponeurosis of the Transversalis. The anterior crural nerve is first situated in 
the substance of the muscle, and emerges from its outer border at the lower part. 
The lumbar plexus is situated in the posterior part of the substance of the muscle. 
By its inner side the muscle is in relation with the bodies of the lumbar vertebrae, 
the lumbar arteries, the ganglia of the sympathetic nerve, and their branches of 
communication with the spinal nerves, the lumbar glands, the vena cava inferior on 
the right and the aorta on the left side. In the thigh it is in relation in front with 
the fascia lata, behind with the capsular ligament of the hip, from wdiich it is sep- 
arated by a synovial bursa which sometimes communicates with the cavity of the 
joint through an opening of variable size; by its inner border with the Pectineus 
and the femoral artery, which slightly overlaps it; by its outer border with the 
anterior crural nerve and Iliacus muscle. 
The Psoas parvus is a long slender muscle placed in front of the preceding. It 
arises from the sides of the bodies of the last dorsal and first lumbar vertebrae, and 
from the intervertebral substance between them. It forms a small flat muscular 
bundle which terminates in a long flat tendon inserted into the ilio-pectineal emi- 
nence, and continuous, by its outer border, with the iliac fascia. This muscle is 
often absent, and, according to Cruveilhier, sometimes double. 
Relations.-It is covered by the peritoneum, and at its origin by the ligamen- 
tum arcuatum internum; it rests on the Psoas magnus. 
The Iliacus is a flat radiated muscle which fills up the whole of the internal iliac 
fossa. It arises from the upper half of the iliac fossa and inner margin of the crest 
of the ilium; behind, from the ilio-lumbar ligament and base of the sacrum ; in 
front, from the anterior superior and anterior inferior spinous processes of the ilium, 
from the notch between them, and by a few fibres from the capsule of the hip-joint. 
The fibres converge to be inserted into the outer side of the tendon of the Psoas, 
some of them being prolonged into the oblique line which extends from the lesser 
trochanter to the linea aspera. [These two muscles (Iliacus and Psoas magnus) are 
often spoken of as the " Ilio-psoas, " a bicipital muscle. On bending well backward 
they can be felt just below Poupart's ligament, outside the femoral artery.] 
Relations within the Pelvis.-By its anterior surface with the iliac fascia, 
which separates the muscle from the peritoneum, and with the external cutaneous 
nerve ; on the right side with the caecum ; on the left side with the sigmoid flexure 
of the colon ; by its posterior surface with the iliac fossa; by its inner border with 
the Psoas magnus and anterior crural nerve. In the thigh it is in relation, by its 
anterior surface, with the fascia lata, Rectus, and Sartorius; behind with the cap- FASCIAE OF THE THIGH. 
465 
sule of the hip-joint, a synovial bursa common to it and the Psoas magnus being 
interposed. 
Nerves.-The Psoas magnus, and the Psoas parvus when it exists, are supplied 
by the anterior branches of the lumbar nerves, the Iliacus by the anterior crural. 
Actions.-The Psoas and Iliacus muscles, acting from above, flex the thigh upon 
the pelvis, and at the same time rotate the femur outward, from the obliquity of their 
insertion into the inner and back part of that bone. Acting from below, the femur 
being fixed, the muscles of both sides bend the lumbar portion of the spine and pel- 
vis forward. They also serve to maintain the erect position by supporting the spine 
and pelvis upon the femur, and assist in raising the trunk when the body is in the 
recumbent posture. 
The Psoas parvus is a tensor of the iliac fascia. 
Anterior Femoral Region. 
Tensor vaginae femoris. 
Sartorius. 
Rectus. 
Vastus externus. 
Vastus internus. 
Crureus. 
Subcrureus. 
Dissection.-To expose the muscles and fascise in this region, make an incision along Pou- 
part's ligament from the spine of the ilium to the pubes ; a vertical incision from the centre of 
this along the middle of the thigh to below the knee-joint; and a transverse incision from the 
inner to the outer side of the leg at the lower end of the vertical incision. The flaps of integu- 
ment having been removed, the superficial and deep fascim should be examined. The more 
advanced student should commence the study of this region by an examination of the anatomy 
of femoral hernia and Scarpa's triangle, the incisions for the dissection of which are marked out 
in the accompanying figure. 
Fasciae of the Thigh 
The Superficial Fascia forms a continuous layer over the whole of the lower 
extremity, consisting of areolar tissue, containing in its meshes much adipose mat- 
ter, and capable of being separated into two or more layers, between which are 
found the superficial vessels and nerves. It varies in thickness in different parts 
of the limb : in the sole of the foot it is so thin as to be scarcely demonstrable, the 
integument being closely adherent to the deep fascia beneath, but in the groin it is 
thicker, and the two layers are separated from one another by the superficial inguinal 
glands, the internal saphenous vein, and several smaller vessels. One of these two 
layers, the superficial, is continuous above with the superficial fascia of the abdomen, 
the deep layer becoming blended with the fascia lata a little below Poupart's ligament. 
The deep layer of superficial fascia is intimately adherent to the margins of the saphe- 
nous opening in the fascia lata, and pierced in this situation by numerous small blood- 
and lymphatic vessels: hence the name cribriform [cribrum, a sieve] fascia which has 
been applied to it. Subcutaneous bursae are found in the superficial fascia over the 
patella, point of the heel, and phalangeal articulations of the toes. 
The Deep Fascia of the thigh is exposed on the removal of the superficial fascia, 
and is named, from its great extent, the Fascia lata; it forms a uniform investment 
for the whole of this region of the limb, but varies in thickness in different parts; 
thus it is thicker in the upper and outer part of the thigh, where it receives a 
fibrous expansion from the Gluteus maximus muscle, and the Tensor vaginae femoris 
is inserted between its layers: it is very thin behind and at the upper and inner 
part, where it covers the Adductor muscles; and again becomes stronger around the 
knee, receiving fibrous expansions from the tendon of the Biceps externally, and 
from the Sartorius, Gracilis, Semitendinosus, and Quadriceps extensor cruris in 
front. The fascia lata is attached above and behind to the back of the sacrum and 
coccyx ; externally, to the crest of the ilium; in front, to Poupart's ligament and 
to the body and ramus of the pubes; and internally, to the descending ramus of 
the pubes, to the ascending ramus and tuberosity of the ischium, and .to the lower 466 
MUSCLES AND FASCINE. 
border of the great sacro-sciatic ligament. From its attachment to the crest of the 
ilium it passes down over the Gluteus medius muscle to the upper border of the 
Gluteus maximus, where it splits into two layers, one passing superficial to and the 
other beneath this muscle. At the lower border of the muscle the two layers unite, 
and externally, just behind the great trochanter, receive the greater part of the 
tendon of insertion of the Gluteus maximus, and become proportionally thickened. 
The portion of the fascia lata arising from the front part of the crest of the ilium, 
corresponding to the origin of the Tensor vaginse femoris, passes down the outer 
side of the thigh as two layers, one superficial and the other beneath this muscle; 
these at its lower border become blended together into a thick and strong band, 
having first received the insertion of the muscle. This band is continued down- 
ward, under the name of the ilio-tibial band, to be inserted into the external tube- 
rosity of the tibia and the head of the fibula. Below, the fascia lata is attached to 
all the prominent points around the knee-joint-viz. the condyles of the femur, 
tuberosities of the tibia, and head of the fibula. From the inner surface of the 
fascia lata are given off' two strong intermuscular septa which are attached to the 
whole length of the linea aspera: the external and stronger one, which extends 
from the insertion of the Gluteus maximus to the outer condyle, separates the 
Vastus externus in front from the short head of the Biceps behind, and gives par- 
tial origin to those muscles; the internal one, the thinner of the two, separates the 
Vastus internus from the Adductor muscles. Besides these there are numerous 
smaller septa separating the individual muscles and enclosing each in a distinct 
sheath. At the upper and inner part of the thigh, a little below Poupart's liga- 
ment, a large oval-shaped aperture is observed after the superficial fascia has been 
cleared off: it transmits the internal saphenous vein and other smaller vessels, and 
is termed the saphenous opening. In order more correctly to consider the mode of 
formation of this aperture, the fascia lata is described as consisting, in this part of 
the thigh, of two portions, an iliac portion and a pubic portion. 
The iliac portion is all that part of the fascia lata on the outer side of the saph- 
enous opening. It is attached externally to the crest of the ilium, and its anterior 
superior spine to the whole length of Poupart's ligament as far internally as the 
spine of the pubes, and to the pectineal line in conjunction with Gimbernat's liga- 
ment. From the spine of the pubes it is reflected downward and outward, forming 
an arched margin, the falciform border [falx, a scythe] or outer boundary of the 
saphenous opening: this margin overlies and is adherent to the anterior layer of the 
sheath of the femoral vessels; to its edge is attached the cribriform fascia and below 
it is continuous with the pubic portion of the fascia lata. 
The pubic portion is situated at the inner side of the saphenous opening; at the 
lower margin of this aperture it is continuous with the iliac portion [passing in front 
of the vessels] ; traced upward, it is seen to cover the surface of the Pectineus mus- 
cle, and, passing behind the sheath of the femoral vessels, to which it is closely united, 
is continuous with the sheath of the Psoas and Iliacus muscles, and is attached above 
to the ilio-pectineal line and becomes continuous with the iliac fascia. From this 
description it may be observed that the iliac portion of the fascia lata passes in front 
of the femoral vessels, and the pubic portion behind them, so that an apparent aper- 
ture exists between the two, through which the internal saphenous joins the femoral 
vein.1 
The fascia should now be removed from the surface of the muscles. This may be effected 
by pinching it up between the forceps, dividing it, and separating it from each muscle in the 
course of its fibres. 
The Tensor vaginse femoris arises from the anterior part of the outer lip of 
the crest of the ilium, and from the outer surface of the anterior superior spinous 
process between the Gluteus medius and Sartorius. It is inserted into the fascia 
lata about one-fourth down the outer side of the thigh. From the point of inser- 
tion the fascia is continued downward to the head of the tibia as a thickened band, 
1 These parts will be again more particularly described with the anatomy of Hernia. FASCIAE OF THE THIGH. 
467 
the ilio-tibial band. [If the two hands are placed on these muscles, and the weight 
thrown on each leg alternately by a rocking motion, they can easily be felt. By 
standing on one leg the furrow of the ilio-tibial band can often be seen, especially 
in female models.] 
Relations.-By its superficial surface with the fascia lata and the integument; 
by its deep surface with the Gluteus medius, Rectus femoris, Vastus externus, 
and the ascending branches of the external circumflex artery; by its anterior 
border with the Sartorius, from which it is separated below by a triangular space 
in which is seen the Rectus femoris ; by its posterior border with the Gluteus medius. 
The Sartorius [sartor, a tailor], the longest muscle in the body, is flat, narrow, 
and ribbon-like: it arises by tendinous fibres from the anterior superior spinous 
process of the ilium and the upper half of the notch below it, passes obliquely 
across the upper and anterior part of the thigh from the outer to the inner side of 
the limb, then descends vertically as far as the inner side of the knee, passing 
behind the inner condyle of the femur, and terminates in a tendon which, curving 
obliquely forward, expands into a broad aponeurosis inserted into the upper part of 
the inner surface of the shaft of the tibia nearly as far forward as the crest. This 
expansion is inserted into the bone by an inverted U-shaped aponeurosis; part of it 
is inserted behind the attachment of the Gracilis and Semitendinosus, and another 
part, arching over the upper border of the tendon of the Gracilis, is inserted into 
the tibia in front of these muscles. An offset is derived from the upper margin of 
this aponeurosis which blends with the fibrous capsule of the knee-joint, and 
another, given off from its lower border, blends with the fascia on the inner side of 
the leg. [The muscle can be obscurely seen in outline. Its borders, especially the 
inner, are marked by furrows.] The relations of this muscle to the femoral artery 
should be carefully examined, as its inner border forms the chief guide in tying the 
artery. In the upper third of the thigh it forms the outer side of a triangular 
space, Scarpa's triangle, the inner side of which is formed by the Adductor longus, 
and the base, turned upward, by Poupart's ligament; the femoral artery passes per- 
pendicularly through the middle of this space from its base to its apex. In the 
middle third of the thigh the femoral artery lies first along the inner border, and 
then behind the Sartorius. 
Relations.-By its superficial surface with the fascia lata and integument; by 
its deep surface with the Iliacus, Psoas, Rectus, Vastus internus, anterior crural 
nerve, sheath of the femoral vessels, Adductor longus, Adductor magnus, Gracilis, 
long saphenous nerve, and internal lateral ligament of the knee-joint. 
The Quadriceps extensor [cruris] includes the four remaining muscles on the 
front of the thigh. It is the great Extensor, muscle of the leg, forming a large 
fleshy mass which covers the front and sides of the femur, being united below into 
a single tendon attached to the patella, and above subdividing into separate por- 
tions, which have received distinct names. Of these, one occupying the middle of 
the thigh, connected above with the ilium, is called the Rectus femoris, from its 
straight course. The other divisions lie in immediate connection with the shaft of 
the femur, which they covei' from the condyles to the trochanters. The portion on 
the outer side of the femur is termed the Vastus externus ; that covering the inner 
side, the Fhstus internus ; and that covering the front of the femur, the Crureus. 
The two latter portions are, however, so intimately blended as to form but one muscle. 
The Rectus femoris is situated in the middle of the anterior region of the 
thigh; it is fusiform in shape, and its superficial fibres are arranged in a bipenni- 
form manner, the deep fibres running straight down to the deep aponeurosis. It 
arises by two tendons: one, the straight tendon or short head, from the anterior 
inferior spinous process of the ilium; the other is flattened and curves outward to 
be attached to a groove above the brim of the acetabulum; this is the reflected ten- 
don or long head of the Rectus; it unites with the straight tendon at an acute 
angle, and then spreads into an aponeurosis from which the muscular fibres arise.1 
1 Mr. W. R. Williams, in an interesting paper in the Journ. of Anat. and Phys., vol. xiii. p. 
204, points out that the reflected tendon is the real origin of the muscle, and is alone present in early 468 
MUSCLES AND FASCIAE. 
The muscle terminates in a broad and thick aponeurosis which occupies the lower 
two-thirds of its posterior surface, and, gradually becoming narrowed into a flat- 
tened tendon, is inserted into the patella in common with the Vasti and Crureus. 
[This tendon of the Rectus produces the very marked suprapatellar flat, especially 
well seen in the model when the muscle is called into vigorous action by attempted 
over-extension of the leg.] 
Relations.-By its superficial surface with the anterior fibres of the Gluteus 
minimus, the Tensor vaginae femoris, Sartorius, and the Psoas and Iliacus; by its 
lower three-fourths with the fascia lata; by its posterior surface with the hip-joint, 
the external circumflex vessels, and the Crureus and Vasti muscles. 
The three remaining muscles have been described collectively by some anatomists, 
separate from the Rectus, under the name of the Triceps extensor cruris. In order 
to expose them divide the Sartorius and Rectus across the middle and turn them 
aside, when the muscles in question will be fully brought into view. 
The Vastus externus is the largest part of the Quadriceps extensor. It arises 
by a broad aponeurosis which is attached to the tubercle of the femur, to the ante- 
rior border of the great trochanter, to a horizontal ridge on its outer surface, to a 
rough line leading from the trochanter major to the linea aspera, and to the whole 
length of the outer lip of the linea aspera: this aponeurosis covers the upper three- 
fourths of the muscle, and from its inner surface many fibres arise. A few addi- 
tional fibres arise from the tendon of the Gluteus maximus and from the external 
intermuscular septum between the Vastus externus and short head of the Biceps. 
The fibres form a large fleshy mass which is attached to a strong aponeurosis placed 
on the under surface of the muscle at its lower part: this becomes contracted and 
thickened into a flat tendon, which is inserted into the outer border of the patella, 
blending with the great extensor tendon. 
Relations.-By its superficial surface with the Rectus, the Tensor vaginae fem- 
oris, the fascia lata, and the Gluteus 
maximus, from which it is separated 
by a synovial bursa; by its deep sur- 
face with the Crureus, some large 
branches of the external circumflex 
artery and anterior crural nerve be- 
ing interposed. 
The Vastus internus and the 
Crureus are so inseparably con- 
nected together as to form but one 
muscle, as which it will be accord- 
ingly described. It is the smallest 
portion of the Quadriceps extensor. 
The anterior portion of it, covered 
by the Rectus, is called the Crureus; 
the internal portion, which lies im- 
mediately beneath the fascia lata, 
the Vastus internus. It arises by 
an aponeurosis which is attached to 
the lower part of the line that ex- 
tends from the inner side of the neck 
of the femur to the linea aspera, from 
the whole length of the inner lip of 
the linea aspera, from the ridge lead- 
ing from the linea aspera to the internal condyle and internal intermuscular septum. 
It also arises from nearly the whole of the internal, anterior, and external surfaces 
of the shaft of the femur, limited above by the line between the two trochanters, and 
foetal life. The direct tendon is merely an accessory band of condensed fascia. The paper will well 
repay perusal, though in some particulars I think the description in the text more generally 
accurate.-Ed. 
[Fig. 335. 
Section of the Right Thigh at the Apex of Scarpa's Triangle 
(drawn by G. E. Pearse): 1, profunda vessels; 2, Adductor 
longus; 3, femoral vessels; 4, superficial obturator nerve; 5, 
Sartorius; 6, Gracilis; 7_, external cutaneous nerve; 8, Pec- 
tineus; 9, Rectus femoris; 10, Adductor brevis; 11, anterior 
crural nerve; 12, deep obturator nerve; 13, external circum- 
flex vessels; 14, Adductor magnus; 15, Tensor vaginae fem- 
oris; 16, Semimembranosus; 17, Vastus internus and crureus; 
18, Semitendinosus; 19, Vastus externus; 20, small sciatic 
nerve; 21, Biceps femoris; 22, great sciatic nerve (Heath).] FASCIAE OF THE THIGH. 
469 
extending below to within the lower fourth of the bone. From these different ori- 
gins the fibres converge to a broad aponeurosis which covers the anterior surface of 
the middle portion of the muscle (the Crureus) and the deep surface of the inner 
division of the muscle (the Vastus internus), and which gradually narrows down to 
its insertion into the patella, where it blends with the other portions of the Quadri- 
ceps extensor. The muscular fibres of the Vastus internus extend lower down than 
those of the Vastus externus, so that the capsule of the joint is less covered with mus- 
cular fibres on the outer than on the inner side. [The structure of the Quadriceps mus- 
cles is an excellent illustration of adaptation for great strength and short range of 
action. (See p. 362.) The relation of the fibres to the patella is important. Those 
of the Vastus externus run down obliquely, and its belly terminates well above the 
patella. The belly of the Vastus internus extends almost to the lower border of the 
patella, its lower fibres running horizontally, and so directly opposing external dislo- 
cation, the very one to which the patella is most exposed by the angle at the knee. 
When the model attempts over-extension of the leg, and so calls the Quadriceps into 
violent action, the Vastus internus shows as a triangular roll between the Rectus and 
the Sartorius.] 
Relations.-By its superficial surface with the Psoas and Iliacus, the Rectus, 
Sartorius, Pectineus, Adductors, and fascia lata, femoral vessels, and saphenous 
nerve; by its deep surface with the femur, Subcrureus, and synovial membrane 
of the knee-joint. 
The student will observe the striking analogy that exists between the Quadriceps 
extensor and the Triceps muscle in the upper extremity. So close is this similarity 
that M. Cruveilhier has described it under the name of the Triceps femoralis. Like 
the Triceps extensor cubiti, it consists of three distinct divisions or heads: a middle 
or long head [the Rectus], analogous to the long head of the Triceps, attached to the 
ilium; and two other portions, which may be called the external and internal heads 
of the Triceps femoralis. These, it will be noticed, are strictly analogous to the outer 
and inner heads of the Triceps in the arm. 
The tendons of the different portions of the Quadriceps extensor unite at the lower 
part of the thigh so as to form a single strong tendon, which is inserted into the upper 
part of the patella. More properly, the patella may be regarded as a sesamoid bone 
developed in the tendon of the Quadriceps, and the ligamentum patellse, wThich is con- 
tinued from the lower part of the patella to the tubercle of the tibia, as the proper 
tendon of insertion of the muscle. A synovial bursa [the subpateliar is 
interposed between the tendon and the upper part of the tubercle of the tibia [and 
another and more important one exists in front of the patella itself-the prepatellar 
bursa, which is involved in "housemaid's knee" (Fig. 273, p. 350)]. From the 
tendons corresponding to the Vasti a fibrous prolongation is derived, which is 
attached below to the upper extremities of the tibia and fibula, and which serves 
to protect the knee-joint, being strengthened on its outer side by the fascia lata. 
The Subcrureus is a small muscle, usually distinct from the Crureus, but occa- 
sionally blended with it, which arises from the anterior surface of the lower part of 
the shaft of the femur, and is inserted into the upper part of the synovial pouch 
that extends upward from the knee-joint behind the patella. It sometimes consists 
of two separate muscular bundles. 
Nerves.-The Tensor vaginae femoris is supplied by the superior gluteal nerve, 
the other muscles of this region by branches from the anterior crural. 
Actions.-The Tensor vaginae femoris is a tensor of the fascia lata: continuing 
its action, the oblique direction of its fibres enables it to rotate the thigh inward. 
In the erect posture, acting from below, it will serve to steady the pelvis upon the 
head of the femur, and by means of the ilio-tibial band it steadies the condyles of 
the femur on the articular surfaces of the tibia, and assists the Gluteus maximus in 
supporting the knee in the extended position. The Sartorius flexes the leg upon 
the thigh, and, continuing to act, flexes the thigh upon the pelvis; it next rotates 
the thigh outward. It was formerly supposed to adduct the thigh so as to cross 
one leg over the other, and hence received its name of Sartorius, or tailor's muscle 470 
MUSCLES AND FASCIAE. 
(sartor, a tailor), because it was supposed to assist in crossing the legs in the squat- 
ting position. When the knee is bent the Sartorius assists the Semitendinosus and 
Popliteus in rotating the tibia inward. Taking its fixed point from the leg, it flexes 
the pelvis upon the thigh, and, if one muscle acts, assists in rotating the pelvis. The 
Quadriceps extensor extends the leg upon the thigh. Taking its fixed point from 
the leg, as in standing, tliis muscle will act upon the femur, supporting it perpen- 
dicularly upon the head of the tibia, and thus maintaining the entire weight of the 
body. [In going up stairs it brings the flexed femur into a straight line with the 
tibia (extends the femur), and so lifts the body; and in going down stairs, stooping 
to make a courtesy, etc., it holds the femur, and lets it yield gradually in flexion 
instead of suddenly.] The Rectus muscle assists the Psoas and Iliacus in support- 
ing the pelvis and trunk upon the femur or in bending it forward. 
Internal Femoral Region. 
Gracilis. 
Pectineus. 
Adductor longus. 
Adductor brevis. 
Adductor magnus. 
Dissection.-These muscles are at once exposed by removing the fascia from the fore part 
and inner side of the thigh. The limb should be abducted, so as to render the muscles tense 
and easier of dissection. 
The Gracilis (Figs. 334, 338) is the most superficial muscle on the inner side 
of the thigh. It is thin and flattened, broad above, narrow and tapering below. 
It arises by a thin aponeurosis between two and three inches in breadth from the 
inner margin of the ramus of the pubes and ischium. The fibres pass vertically 
downward, and terminate in a rounded tendon which passes behind the internal 
condyle of the femur, and, curving round the inner tuberosity of the tibia, becomes 
flattened, and is inserted into the upper part of the inner surface of the shaft of che 
tibia below the tuberosity. The tendon of this muscle is situated immediately above 
that of the Semitendinosus, and is surrounded by the tendon of the Sartorius, with 
which it is in part blended. As it passes across the internal lateral ligament of the 
knee-joint it is separated from it by a synovial bursa common to it and the Semi- 
tendinosus muscle. 
Relations.-By its superficial surface with the fascia lata and the Sartorius 
below; the internal saphenous vein crosses it obliquely near its lowei' part, lying 
superficial to the fascia lata. The internal saphenous nerve emerges between its 
tendon and that of the Sartorius. By its deep surface with the three Adductors 
and the internal lateral ligament of the knee-joint. 
The Pectineus (Fig. 334) is a flat, quadrangular muscle situated at the anterior 
part of the upper and inner aspect of the thigh. It arises from the linea ilio-pec- 
tinea, from the surface of bone in front of it between the pectineal eminence and 
spine of the pubes, and from a tendinous prolongation of Gimbernat's ligament, 
which is attached to the crest of the pubes and is continuous with the fascia cover- 
ing the anterior surface of the muscle; the fibres pass downward, backward, and 
outward to be inserted into a rough line leading from the trochanter minor to the 
linea aspera. 
Relations.-By its anterior surface with the pubic portion of the fascia lata, 
which separates it from the femoral vessels and internal saphenous vein; by its pos- 
terior surface with the hip-joint, the Adductor brevis and Obturator externus muscles, 
the obturator vessels and nerve being interposed ; by its outer border with the Psoas, 
a cellular interval separating them, through which passes the internal circumflex 
artery; by its inner border with the margin of the Adductor longus. 
The Adductor longus, the most superficial of the three Adductors, is a flat trian- 
gular muscle lying on the same plane as the Pectineus, with which it is often blended 
above. It arises by a flat narrow tendon from the front of the pubes, at the angle 
of junction of the crest with the symphysis, and soon expands into a broad fleshy INTERNAL FEMORAL REGION. 
471 
belly, which, passing downward, backward, and outward, is inserted by an aponeuro- 
sis into the middle third of the linea aspera, 
between the Vastus internus and the Ad- 
ductor magnus. 
Relations.-By its anterior surface with 
the fascia lata, and near its insertion with the 
femoral artery and vein; by its posterior sur- 
face with the Adductor brevis and magnus, 
the anterior branches of the obturator ves- 
sels and nerve, and with the profunda artery 
and vein near its insertion; by its outer bor- 
der with the Pectineus; by its inner border 
with the Gracilis. 
The Pectineus and Abductor longus should now 
be divided near their origin and turned downward, 
when the Adductor brevis and Obturator externus 
will be exposed. 
The Adductor brevis is situated imme- 
diately behind the two preceding muscles. It 
is somewhat triangular in form, and arises by 
a narrow origin from the outer surface of the 
descending ramus of the pubes, between the 
Gracilis and Obturator externus. Its fibres, 
passing backward, outward, and downward, 
are inserted by an aponeurosis into the lower 
part of the line leading from the lesser tro- 
chanter to the linea aspera and the upper 
part of the linea aspera, immediately behind 
the Pectineus and upper part of the Adduc- 
tor longus. [The tendon of origin of these 
two Adductors can easily be felt and seen by 
putting them into action or by merely sep- 
arating the thighs widely.] 
Relations.-By its anterior surface with 
the Pectineus, Adductor longus, and anterior 
branches of the obturator vessels and nerve; 
by its posterior surface with the Adductor 
magnus and posterior branches of the obtu- 
rator vessels and nerve ; by its outer border 
with the Obturator externus and conjoined 
tendon of the Psoas and Iliacus ; by its inner 
border with the Gracilis and Adductor mag- 
nus. This muscle is pierced near its insertion 
by the middle perforating branch of the pro- 
funda artery. 
The Abductor brevis should now be cut away 
near its origin and turned outward, when the entire 
extent of the Abductor magnus will be exposed. 
The Adductor magnus is a large trian- 
gular muscle forming a septum between the 
muscles on the inner and those on the back of 
the thigh. It arises from a small part of the 
descending ramus of the pubes, from the as- 
cending ramus of the ischium, and from the outer margin and under surface of the 
tuberosity of the ischium. Those fibres which arise from the ramus of the pubes 
Fig. 336 
Deep Muscles of the Internal Femoral Region. 472 
MUSCLES AND FASCIAE. 
are very short, horizontal in direction, and are inserted into the rough line lead- 
ing from the great trochanter to the linea aspera, internal to the Gluteus maxi- 
mus ; those from the ramus of the ischium are directed downward and outward 
with different degrees of obliquity, to be inserted, by means of a broad aponeur- 
osis, into the whole length of the linea aspera and the upper part of its internal 
bifurcation below. The internal portion of the muscle, consisting principally of 
those fibres which arise from the tuberosity of the ischium, forms a thick fleshy 
mass consisting of coarse bundles which descend almost vertically, and terminate 
about the lower third of the tliigh in a rounded tendon, which is inserted into the 
tubercle above the inner condyle of the femur, being connected by a fibrous 
expansion to the line leading upward from the tubercle to the linea aspera. Be- 
tween the two portions of the muscle an angular interval is left, tendinous in 
front, fleshy behind, for the passage of the femoral vessels into the popliteal space. 
The external portion of the muscle at its attachment to the femur presents three 
or four osseo-aponeurotic openings formed by tendinous arches attached to the 
bone, from which muscular fibres arise. The three superior of these apertures are 
for the three perforating arteries, and the fourth, when it exists, for the terminal 
branch of the profunda. This muscle gives off an aponeurosis which passes in front 
of the femoral vessels and joins with the Vastus internus, forming the covering of 
Hunter's canal. 
Relations.-By its anterior surface with the Pectineus, Adductor brevis, Adduc- 
tor longus, and the femoral vessels; by its posterior surface with the great sciatic 
nerve, the Gluteus maximus, Biceps, Semitendinosus, and Semimembranosus; by its 
superior or shortest border it lies parallel with the Quadratus femoris, the internal 
circumflex artery passing between them; by its internal or longest border, with the 
Gracilis, Sartorius, and fascia lata; by its external or attached border it is inserted 
into the femur behind the Adductor brevis and Adductor longus, which separate it 
from the Vastus internus, and in front of the Gluteus maximus and short head of 
the Biceps, which separate it from the Vastus externus. 
Nerves.-All the muscles of this group are supplied by the obturator nerve. 
The Pectineus receives additional branches from the accessory obturator and ante- 
rior crural, and the Adductor magnus an additional branch from tlie great sciatic. 
Actions.-The Pectineus and three Adductors adduct the thigh powerfully; 
they are especially used in horse exercise, the sides of the horse being grasped 
between the knees by the action of these muscles. In consequence of the obliquity 
of their insertion into the linea aspera, they rotate the thigh outward, assisting the 
external Rotators, and when the limb has been abducted they draw it inward, carry- 
ing the thigh across that of the opposite side. The Pectineus and Adductor brevis 
and longus assist the Psoas and Iliacus in flexing the thigh upon the pelvis. In 
progression also all these muscles assist in drawing forward the hinder limb. The 
Gracilis assists the Sartorius in flexing the leg and rotating it inward; it is also an 
Adductor of the thigh. If the lower extremities are fixed, these muscles may take 
their fixed point from below and act upon the pelvis, serving to maintain the body 
in an erect posture, or, if their action is continued, to flex the pelvis forward upon 
the femur. 
Gluteal Region. 
Gluteus maximus. 
Gluteus medius. 
Gluteus minimus. 
Pyriformis. 
Gemellus superior. 
Obturator interims. 
Gemellus inferior. 
Obturator externus. 
Quadratus femoris. 
Dissection (Fig. 337).-The subject should be turned on its face, a block placed beneath the 
pelvis to make the buttocks tense, and the limbs allowed to hang over the end of the table with 
the foot inverted and the thigh abducted. Make an incision through the integument along the 
back part of the crest of the ilium and margin of the sacrum to the tip of the coccyx, and carry GLUTEAL REGION. 
473 
a second incision from that point obliquely downward and outward to the outer side of the thigh, 
four inches below the great trochanter. The portion of integument included between these incis- 
ions, together with the superficial fascia, is to be re- 
moved in the direction shown in the figure, when the 
Gluteus maximus and the dense fascia covering the 
Gluteus medius will be exposed. 
The Gluteus maximus (Fig. 338), the most 
superficial muscle in the gluteal region, is a very 
broad and thick fleshy mass, of a quadrilateral 
shape, which forms the prominence of the nates. 
Cts large size is one of the most characteristic 
points in the muscular system in man, connected 
as it is with the power he has of maintaining the 
trunk in the erect posture. In structure the 
muscle is remarkably coarse, being made up of 
muscular fasciculi lying parallel with each other 
and collected together into large bundles, sepa- 
rated by deep cellular intervals. It arises from 
the superior curved line of the ilium and the 
portion of bone, including the crest, immediately 
behind it-from the posterior surface of the lower 
part of the sacrum, the side of the coccyx, the 
aponeurosis of the Erector spinse muscle, and 
the great sacro-sciatic ligament. The fibres are 
directed obliquely downward and outward : those 
forming the upper and larger portion of the mus- 
cle (after converging somewhat) terminate in a 
thick tendinous lamina, which passes across the 
great trochanter and is inserted into the fascia 
lata covering the outer side of the thigh, the 
lower portion of the muscle being inserted into 
the rough line leading from the great trochanter 
to the linea aspera between the Vastus externus 
and Adductor magnus. 
[There is well seen in the living model, when 
this muscle is contracted, a great dimple or hol- 
low corresponding to the tendon of the Gluteus 
maximus. At its anterior border the great tro- 
chanter is felt. The lower border of this muscle overhangs the thigh and forms the 
" gluteo-femoral crease." This crease or groove undergoes marked modifications 
as the model changes the position of his leg, especially in flexion and extension. 
Hence its value in the diagnosis of coxalgia.] 
Three synovial bursce are usually found separating the under surface of this mus- 
cle from the eminences which it covers. One of these, of large size and generally 
multilocular, separates it from the great trochanter. A second, often wanting, is 
situated on the tuberosity of the ischium. A third is found between the tendon of 
this muscle and the Vastus externus. 
Relations.-By its superficial surface with a thin fascia which separates it from 
the subcutaneous tissue; by its deep surface, from above downward, with the ilium, 
sacrum, coccyx, and great sacro-sciatic ligament, part of the Gluteus medius, Pyri- 
formis, Gemelli, Obturator internus, Quadratus femoris, the tuberosity of the ischium, 
great trochanter, the origin of the Biceps, Semitendinosus, Semimembranosus, and 
Adductor magnus muscles. The gluteal vessels and superior gluteal nerve are seen 
issuing from the pelvis above the Pyriformis muscle, the sciatic and internal pudic 
vessels and nerves, and the nerve to the Obturator internus muscle below it. Its 
upper border is thin, and connected with the Gluteus medius by the fascia lata. Its 
lower border is free and prominent. 
Fig. 337. 
1 . Dissection of 
GLUTEAL REGION 
3 , BACK of THIGH 
Z « POPLITEAL SPACE 
fy . BACK ef LEG 
5 . SOLE of FOOT 
Dissection of Lower Extremity, posterior 
view. 474 
MUSCLES AND FASCIAE 
Dissection.-Now divide the Glu- 
teus maxim us near its origin by a 
vertical incision carried from its up- 
per to its lower border; a cellular 
interval will be exposed separating 
it from the Gluteus medius and Ex- 
ternal rotator muscles beneath. The 
upper portion of the muscle is to be 
altogether detached, and the lower 
portion turned outward: the loose 
areolar tissue filling up the inter- 
space between the trochanter major 
and tuberosity of the ischium being 
removed, the parts already enume- 
rated as exposed by the removal of 
this muscle will be seen. 
The Gluteus medius is a 
broad, thick, radiated muscle 
situated on the outer surface of 
the pelvis. Its posterior third 
is covered by the Gluteus maxi- 
mus, its anterior two-thirds by 
the fascia lata, which separates 
it from the integument. It arises 
from the outer surface of the 
ilium, between the superior and 
middle curved lines, and from 
the outer lip of that portion of 
the crest which is between them; 
it also arises from the dense fas- 
cia (gluteal aponeurosis) covering 
its anterior part. The fibres con- 
verge to a strong flattened ten- 
don which is inserted into the 
oblique line which traverses the 
outer surface of the great tro- 
chanter. A synovial bursa sep- 
arates the tendon of the muscle 
from the surface of the tro- 
chanter in front of its insertion. 
Relations.-By its super- 
ficial surface with the Gluteus 
maximus behind, the Tensor va- 
ginas femoris and deep fascia in 
front; by its deep surface with 
the Gluteus minimus and the 
gluteal vessels and superior glu- 
teal nerve. Its anterior border 
is blended with the Gluteus min- 
imus. Its posterior border lies 
parallel with the Pyriformis, the 
gluteal vessels intervening. 
This muscle should now be divided 
near its insertion and turned upward, 
when the Gluteus minimus will be 
exposed. 
The Gluteus minimus, the 
smallest of the three Glutei, is 
placed immediately beneath the 
.inner Ha mstring 
Tendons 
5ART0RIUS- 
CRACILIS 
SEMI-TENDINOSUS 
iEMI-MEMBRANOS US 
Outer Hamstring 
Tendo a. 
-BICEPS 
Fig. 338. Muscles of the Hip aud Thigh. GLUTEAL REGION. 
475 
preceding. It is fan-shaped, arising from the outer surface of the ilium between 
the middle and inferior curved lines, and behind from the margin of the great 
sacro-sciatic notch: the fibres converge to the deep surface of a radiated apo- 
neurosis, which, terminating in a tendon, is inserted into an impression on the ante- 
rior border of the great trochanter. A synovial bursa is interposed between the 
tendon and the great trochanter. 
Relations.-By its superficial surface with the Gluteus medius and the gluteal 
vessels and superior gluteal nerve; by its deep surface with the ilium, the reflected 
tendon of the Rectus femoris, and capsular ligament of the hip-joint. Its anterior 
margin is blended with the Gluteus medius. Its posterior margin is often joined 
with the tendon of the Pyriformis. 
The Pyriformis is a flat muscle, pyramidal in shape, lying almost parallel with 
the posterior margin of the Gluteus medius. It is situated partly within the pelvis 
at its posterior part, and partly at the back of the hip-joint. It arises from the front 
of the sacrum by three fleshy digitations attached to the portions of bone between 
the first, second, third, and fourth anterior sacral foramina, and also from the grooves 
leading from the foramina: a few fibres also arise from the margin of the great sacro- 
sciatic foramen and from the anterior surface of the great sacro-sciatic ligament. The 
muscle passes out of the pelvis through the great sacro-sciatic foramen, the upper 
part of which it fills, and is inserted by a rounded tendon into the upper border of the 
great trochanter, being generally blended with the tendon of the Obturator internus. 
Relations.-By its anterior surface, within the pelvis, with the Rectum (espe- 
cially on the left side), the sacral plexus of nerves, and the internal iliac vessels; 
external to the pelvis, with the os innominatum and capsular ligament of the hip- 
joint; by its surface, within the pelvis, with the sacrum, and external to it 
with the Gluteus maximus ; by its upper border, with the Gluteus medius, from which 
it is separated by the gluteal vessels and superior gluteal nerve; by its lower border 
with the Gemellus superior and Coccygeus, the sciatic vessels and nerves, the inter- 
nal pudic vessels and nerve, and muscular branches from the sacral plexus passing 
from the pelvis in the interval between the two muscles. 
The Obturator membrane is a dense layer of interlacing fibres which com- 
pletely closes the obturator foramen, except at its upper and outer part, where a small 
oval canal is left for the obturator vessels and nerve. Each Obturator muscle is con- 
nected with this membrane. 
Dissection.-The next muscle, as well as the origin of the Pyriformis, can only be seen 
when the pelvis is divided and the viscera removed. 
The Obturator internus, like the preceding muscle, is situated partly within the 
cavity of the pelvis, partly at the back of the hip-joint. It arises from the inner 
surface of the anterior and external wall of the pelvis, around the inner side of the 
obturator foramen, being attached to the descending ramus of the pubes and the 
ascending ramus of the ischium, and at the side to the inner surface of the body of 
the ischium, between the margin of the obturator foramen in front, the great sacro- 
sciatic notch behind, and the brim of the true pelvis above. It also arises from the 
inner surface of the obturator membrane except at its lower part, and from the ten- 
dinous arch which completes the canal for the passage of the obturator vessels and 
nerve. The fibres are directed backward and downward, and terminate in four or 
five tendinous bands which are found on its deep surface; these bands are reflected 
at a right angle over the inner surface of the tuberosity of the ischium, which is 
grooved for their reception: the groove is covered with cartilage and lined with a 
synovial bursa. The muscle leaves the pelvis by the lesser sacro-sciatic notch, and 
the tendinous bands unite into a single flattened tendon, which passes horizontally 
outward, and, after receiving the attachment of the Gemelli, is inserted into the upper 
border of the great trochanter in front of the Pyriformis. A synovial bursa, nar- 
row and elongated in form, is usually found between the tendon of this muscle and 
the capsular ligament of the hip: it occasionally communicates with the bursa between 
the tendon and the tuberosity of the ischium, the two forming a single sac. 476 
MUSCLES AND FASCIAE. 
In order to display the peculiar appearances presented by the tendon of this muscle, it must 
be divided near its insertion and reflected outward. 
Relations.- Within the pelvis this muscle is in relation, by its anterior surface, 
with the obturator membrane and inner surface of the anterior wall of the pelvis; 
by its posterior surface with the pelvic and obturator fasciae, which separate it from 
the Levator ani; and it is crossed by the internal pudic vessels and nerve. This 
surface forms the outer boundary of the ischio-rectal fossa. External to the pelvis 
it is covered by the great sciatic nerve and Gluteus maximus, and rests on the back 
part of the hip-joint. 
The Gemelli are two small muscular fasciculi accessories to the tendon of the 
Obturator internus, which is received into a groove between them. They are called 
superior and inferior. 
The Gemellus superior, the smaller of the two, arises from the outer surface 
of the spine of the ischium, and, passing horizontally outward, becomes blended 
with the upper part of the tendon of the Obturator internus, and is inserted with it 
into the upper border of the great trochanter. This muscle is sometimes wanting. 
Relations.-By its superficial surface with the Gluteus maximus and the sciatic 
vessels and nerves; by its deep surf'ace with the capsule of the hip-joint; by its 
upper border with the lower margin of the Pyriformis; by its lower border with 
the tendon of the Obturator internus. 
The Gemellus inferior arises from the upper part of the outer border of the 
tuberosity of the ischium, and, passing horizontally outward, is blended with the 
lower part of the tendon of the Obturator internus, and inserted with it into the 
upper border of the great trochanter. 
Relations.-By its superficial surface with the Gluteus maximus and the sciatic 
vessels and nerves; by its deep surface with the capsular ligament of the hip-joint; 
by its upper border with the tendon of the Obturator internus; by its lower border 
with the tendon of the Obturator externus and Quadratus femoris. 
The Quadratus femoris is a short, flat muscle, quadrilateral in shape (hence its 
name), situated between the Gemellus inferior and the upper margin of the Adductor 
magnus. It arises from the outer border of the tuberosity of the ischium, and, pro- 
ceeding horizontally outward, is inserted into the upper part of the linea quadrati on 
the posterior surface of the trochanter major. A synovial bursa is often found between 
the under surface of this muscle and the lesser trochanter, which it covers. 
Relations.-By its posterior surface with the Gluteus maximus and the sciatic 
vessels and nerves; by its anterior surface with the tendon of the Obturator exter- 
nus and trochanter minor and with the capsule of the hip-joint; by its upper border 
with the Gemellus inferior. Its lower border is separated from the Adductor magnus 
by the terminal branches of the internal circumflex vessels. 
Dissection.-In order to expose the next muscle (the Obturator exterm is), it is necessary to 
remove the Psoas, Iliacus, Pectineus, and Abductor brevis and longus muscles from the front 
and inner side of the thigh, and the Gluteus maximus and Quadratus femori s from the back part. 
Its dissection should consequently be postponed until the muscles of the anterior and internal 
femoral regions have been examined. 
The Obturator externus (Fig. 336) is a flat, triangular muscle which covers 
the outer surface of the anterior wall of the pelvis. It arises from the margin of 
bone immediately around the inner side of the obturator foramen-viz. from the 
body and ramus of the pubes and the ramus of the ischium; it also arises from the 
inner two-thirds of the outer surface of the obturator membrane, and from the ten- 
dinous arch which completes the canal for the passage of the obturator vessels and 
nerves. The fibres converging pass backward, outward, and upward, and terminate 
in a tendon which runs across the back part of the hip-joint and is inserted into the 
digital fossa of the femur. 
Relations.-By its anterior surface with the Psoas, Iliacus, Pectineus, Adduc- 
tor magnus, Adductor brevis, and Gracilis, and more externally with the neck of 
the femur and capsule of the hip-joint; by its posterior surface with the obturator 
membrane and Quadratus femoris. POSTERIOR FEMORAL REGION. 
477 
Nerves.-The Gluteus maximus is supplied by the small sciatic nerve and a 
branch from the sacral plexus; the Gluteus medius and minimis, by the superior 
gluteal; the Pyriformis, Gemelli, Obturator internus, and Quadratus femoris, by 
branches from the sacral plexus; and the Obturator externus, by the obturator 
nerve. 
Actions.-The Glutei muscles, when they take their fixed point from the pelvis, 
are all abductors of the thigh. The Gluteus maximus and the posterior fibres of 
the Gluteus medius and minimus rotate the thigh outward; the anterior fibres of 
the Gluteus medius and the Gluteus minimus rotate it inward. The Gluteus max- 
imus serves to extend the femur and bring the bent thigh into a line with the 
body. The anterior fibres of the Gluteus medius and minimus, on the other hand, 
flex the thigh by drawing the great trochanter forward. The Gluteus maximus is 
also a tensor of the fascia lata. Taking their fixed point from the femur, the 
Glutei muscles act upon the pelvis, supporting it and the whole trunk upon the 
head of the femur, which is specially obvious in standing on one leg. In order to 
gain the erect posture after the effort of stooping, these muscles draw the pelvis 
backward, assisted by the Biceps, Semitendinosus, and Semimembranosus muscles. 
By its connection with the ilio-tibial band the Gluteus maximus steadies the femur 
on the articular surface of the tibia during standing, when the Extensor muscles 
are relaxed. The remaining muscles are powerful rotators of the thigh outward. 
In the sitting posture, when the thigh is flexed upon the pelvis, their action as 
rotators ceases and they become abductors, with the exception of the Obturator 
externus, which still rotates the femur outward. When the femur is fixed the 
Pyriformis and Obturator muscles serve to draw the pelvis forward if it has been 
inclined backward, and assist in steadying it upon the head of the femur. 
Posterior Femoral Region. 
Biceps. 
Semitendinosus. 
Semimembranosus. 
Dissection (Fig. 337).-Make a vertical incision along the middle of the thigh from the lower 
fold of the nates to about three inches below the back of the knee-joint, and there connect it 
with a transverse incision carried from the inner to the outer side of the leg. Make a third 
incision transversely at the junction of the middle with the lower third of the thigh. The integ- 
ument having been removed from the back of the knee and the boundaries of the popliteal 
space examined, the removal of the integument from the remaining part of the thigh should be 
continued, when the fascia and muscles of this region will be exposed. 
The Biceps [flexor cruris] (Fig- 338) is a large muscle, of considerable length, 
situated on the posterior and outer aspect of the thigh. It arises by two heads: 
one, the long head, arises from the lower and inner facet on the back part of the 
tuberosity of the ischium by a tendon common to it and the Semitendinosus; the 
femoral, or short head, arises from the whole length of the outer lip of the linea 
aspera, between the Adductor magnus and Vastus externus, and from the external 
supracondyloid line, to within two inches of the outer condyle; it also arises from 
the external intermuscular septum. The fibres of the long head form a fusiform 
belly, which, passing obliquely downward and a little outward, terminates in an apo- 
neurosis which covers the posterior surface of the muscle and receives the fibres of 
the short head: this aponeurosis becomes gradually contracted into a tendon which 
is inserted into the outer side of the head of the fibula, and by a small slip into the 
lateral surface of the external tuberosity of the tibia. At its insertion the tendon 
divides into two portions, which embrace the long external lateral ligament of the 
knee-joint, a strong prolongation being sent forward to the outer tuberosity of the 
tibia, which gives off an expansion to the fascia of the leg. The tendon of this 
muscle forms the outer hamstring. [Resisted flexion of the leg shows this tendon 
very well.] 
Relations.-By its superficial surface with the Gluteus maximus above, the 
fascia lata and integument in the rest of its extent; by its deep surface with the 
Semimembranosus, Adductor magnus, and Vastus externus, the great sciatic nerve, 478 
MUSCLES AND FASCIAE. 
popliteal artery and vein, and near its insertion with the external head of the Gas- 
trocnemius, Plantaris, the superior external articular artery, and the external pop- 
liteal nerve. 
The Semitendinosus, remarkable for the great length of its tendon, is situated 
at the posterior and inner aspect of the thigh. It arises from th e lower and inner 
facet on the tuberosity of the ischium by a tendon common to it md the long head 
of the Biceps; it also arises from an aponeurosis which connects the adjacent sur- 
faces of the two muscles to the extent of about three inches after their origin. It 
forms a fusiform muscle, which, passing downward and inward, terminates a little 
below the middle of the thigh in a long round tendon which lies along the inner 
side of the popliteal space, then curves around the inner tuberosity of the tibia, and 
is inserted into the upper part of the inner surface of the shaft of that bone, nearly 
as far forward as its anterior border. This tendon is surrounded by the tendon of 
the Sartorius, and lies below that of the Gracilis, to which it is united. A tendin- 
ous intersection is usually observed about the middle of the muscle. 
Relations.-By its superficial surface with the Gluteus maximus and fascia 
lata; by its deep surface with the Semimembranosus, Adductor magnus, inner head 
of the Gastrocnemius, and internal lateral ligament of the knee-joint. 
The Semimembranosus, so called from the membranous expansion on its ante- 
rior and posterior surfaces, is situated at the back part and inner side of the thigh. 
It arises by a thick tendon from the upper and outer facet on the back part of the 
tuberosity of the ischium, above and to the outer side of the Biceps and Semiten- 
dinosus, and is inserted into the groove on the inner and back part of the inner 
tuberosity of the tibia, beneath the internal lateral ligament. The tendon of the 
muscle at its origin expands into an aponeurosis which covers the upper part of its 
anterior surface: from this aponeurosis muscular fibres arise and converge to another 
aponeurosis, which covers the lower part of its posterior surface and contracts into 
the tendon of insertion. The tendon of the muscle at its insertion divides into 
three portions: the middle and main portion is the fasciculus of insertion into the 
back part of the inner tuberosity; it sends down an expansion to cover the Pop- 
liteus muscle. The internal portion consists of a few fibres which join the internal 
lateral ligament of the joint. The posterior division passes upward and outward, 
to be inserted into the back part of the outer condyle of the femur, forming the 
chief part of the posterior ligament of the knee-joint. 
The tendons of the two preceding muscles, with those of the Gracilis and Sarto- 
rius, form the inner hamstring. [Resisted flexion of the leg will show the inner 
hamstrings very well. The tendons of the Semitendinosus and Semimembranosus 
can be readily differentiated, but the others only obscurely. The study on the model 
of the different outlines of the knee posteriorly, and the differences in the popliteal 
space in varying degrees of flexion of the leg, will well repay the time spent 
on it.] 
Relations.-By its superficial surface with the Semitendinosus, Biceps; and 
fascia lata; by its deep) surface with the popliteal vessels, Adductor magnus, and 
inner head of the Gastrocnemius, from which it is separated by a synovial bursa; 
by its inner border with the Gracilis; by its outer border with the great sciatic 
nerve and its internal popliteal branch. 
Nerves.-The muscles of this region are supplied by the great sciatic nerve. 
Actions.-The hamstring muscles flex the leg upon the thigh. When the knee 
is semiflexed the Biceps, in consequence of its oblique direction downward and out- 
ward, rotates the leg slightly outward, and the Semitendinosus, and to a slight extent 
the Semimembranosus, rotate the leg inward, assisting the Popliteus. Taking their 
fixed point from below, these muscles serve to support the pelvis upon the head of 
the femur and to draw the trunk directly backward, as in feats of strength when 
the body is thrown backward in the form of an arch. [For the "ligamentous 
action" of these muscles see p. 301. To show it, stand with the back against the 
wall and keep the pelvis fixed. Flex the thigh, keeping the leg straight. When 
flexed to about one-third, further flexion is arrested by tension and pain at the knee. MUSCLES OF THE LEG. 
479 
Now, keeping the thigh fixed, flex the knee, thus relaxing the hamstrings, when the 
pain disappears and the thigh can be entirely flexed.] 
Surgical Anatomy.-The tendons of these muscles occasionally require subcutaneous 
division in forms of spurious ankylosis of the knee-joint dependent upon permanent contraction 
and rigidity of the Flexor muscles, or from stiffening of the ligamentous and other tissues sur- 
rounding the joint, the result of disease. This is effected by putting the tendon upon the stretch, 
and inserting a narrow sharp-pointed knife between it and the skin: the cutting edge being 
then turned toward the tendon, it should be divided, taking care that the wound in the skin is 
not at the same time enlarged. The relation of the external popliteal nerve to the tendon of the 
Biceps must always be borne in mind in dividing this tendon. 
Dissection (Fig. 333).-The knee should be bent, a block placed beneath it, and the foot kept 
in an extended position; then make an incision through the integument in the middle line of 
the leg to the ankle, and continue it along the dorsum of the foot to the toes. Make a second 
incision transversely across the ankle, and a third in the same direction across the bases of the 
toes ; remove the flaps of integument included between these incisions in order to examine the 
deep fascia of the leg. 
The Deep Fascia of the Leg forms a complete investment to the whole of this 
region of the limb, excepting to the inner surface of the tibia. It is continuous 
above with the fascia lata, receiving an expansion from the tendon of the Biceps on 
the outer side and from the tendons of the Sartorius, Gracilis, and Semitendinosus 
on the inner side; in front it blends with the periosteum covering the subcutaneous 
surface of the tibia, and with that covering the head and external malleolus of the 
fibula; below it is continuous with the annular ligaments of the ankle. It is thick 
and dense in the upper and anterior part of the leg, and gives attachment by its 
deep surface to the Tibialis anticus and Extensor longus digitorum muscles, but 
thinner behind, where it covers the Gastrocnemius and Soleus muscles. Over the 
popliteal space it is much strengthened by transverse fibres which stretch across 
from the inner to the outer hamstring muscles, and it is here perforated by the 
external saphena vein. Its deep surface gives off, on the outer side of the leg, 
two strong intermuscular septa, which enclose the Peronei muscles and separate 
them from the muscles on the anterior and posterior tibial regions, and several 
smaller and more slender processes, which enclose the individual muscles in each 
region; at the same time a broad transverse intermuscular septum, called the deep 
transverse fascia of the leg, intervenes between the superficial and deep muscles in 
the posterior tibio-fibular region. 
Now remove the fascia by dividing it in the same direction as the integument, excepting 
opposite the ankle, where it should be left entire. Commence the removal of the fascia from 
below opposite the tendons, and detach it in the line of direction of the muscular fibres. 
Muscles and Fasciae of the Leg. 
Muscles of the Leg. 
These may be subdivided into three groups: those on the anterior, those on the 
posterior, and those on the outer side. 
Anterior Tibio-fibular Region. 
Tibialis anticus. 
Extensor proprius pollicis. 
Extensor longus digitorum. 
Peroneus tertius. 
The Tibialis anticus is situated on the outer side of the tibia; it is thick and 
fleshy at its upper part, tendinous below. It arises from the outer tuberosity and 
upper two-thirds of the external surface of the shaft of the tibia; from the adjoin- 
ing part of the interosseous membrane; from the deep surface of the fascia; and 
from the intermuscular septum between it and the Extensor longus digitorum: the 
fibres pass vertically downward, and terminate in a tendon which is apparent on 480 
MUSCLES AND FASCIAE. 
Fig. 339. 
the anterior surface of the muscle at the lower 
third of the leg. After passing through the inner- 
most compartment of the anterior annular liga- 
ment, it is inserted into the inner and under sur- 
face of the internal cuneiform bone and base of 
the metatarsal bone of the great toe. [The annu- 
lar ligament holds the tendon of this muscle very 
loosely, and so, if the model stands on one leg, 
the tendon constantly springs into strong relief at 
the ankle in the effort to maintain the equilibrium 
of the body. This reversed action from below up- 
ward is very marked in all the muscles extending 
from the leg to the foot, and should be noticed in 
the case of each one.] 
Relations.-By its anterior surface with the 
fascia and with the annular ligament; by its pos- 
terior surface with the interosseous membrane, 
tibia, ankle-joint, and inner side of the tarsus: 
this surface also overlaps the anterior tibial ves- 
sels and nerve in the upper part of the leg; by 
its inner surface with the tibia; by its outer sur- 
face with the Extensor longus digitorum and Ex- 
tensor proprius pollicis, and the anterior tibial 
vessels and nerve. 
The Extensor proprius pollicis is a thin, 
elongated, and flattened muscle situated between 
the Tibialis anticus and Extensor longus digito- 
rum. It arises from the anterior surface of the 
fibula for about the middle two-fourths of its 
extent, its origin being internal to that of the 
Extensor longus digitorum; it also arises from 
the interosseous membrane to a similar extent. 
The fibres pass downward, and terminate in a 
tendon which occupies the anterior border of the 
muscle, passes through a distinct compartment in 
the horizontal portion of the annular ligament, 
crosses the anterior tibial vessels near the bend 
of the ankle, and is inserted into the base of the 
last phalanx of the great toe. Opposite the meta- 
tarso-phalangeal articulation the tendon gives off 
a thin prolongation on each side which covers the 
surface of the joint. [This tendon also can be 
easily perceived at the ankle and on the dorsum 
of the foot by strongly extending the great toe.] 
Relations.-By its anterior border with the 
fascia and the anterior annular ligament; by its 
posterior border with the interosseous membrane, 
fibula, tibia, ankle-joint, and Extensor brevis digi- 
torum; by its outer side with the Extensor longus 
digitorum above, the dorsalis pedis vessels and an- 
terior tibial nerve below; by its inner side with 
the Tibialis anticus and the anterior tibial vessels 
above. 
The Extensor longus digitorum is an elon- 
gated, flattened, semipenniform muscle situated the 
most externally of all the muscles on the fore part 
of the leg. It arises from the outer tuberosity of 
Muscles of the Front of the Leg. POSTERIOR TIBIO-FIBULAR REGION. 
481 
the tibia, from the upper three-fourths of the anterior surface of the shaft of the 
fibula, from the interosseous membrane and deep surface of the fascia, and from 
the intermuscular septa between it and the Tibialis anticus on the inner and the 
Peronei on the outer side. The tendon enters a canal in the annular ligament with 
the Peroneus tertius, divides into four slips which run across the dorsum of the foot 
and are inserted into the second and third phalanges of the four lesser toes. The 
mode in which the tendons are inserted is the following: the three inner tendons 
opposite the metatarso-phalangeal articulation 
are joined on their outer side by a tendon of 
the Extensor brevis digitorum. They all re- 
ceive a fibrous expansion from the Interossei and 
Lumbricales, and then spread out into a broad 
aponeurosis which covers the dorsal surface of 
the first phalanx : this aponeurosis at the articu- 
lation of the first with the second phalanx di- 
vides into three slips-a middle one, which is 
inserted into the base of the second phalanx, 
and two lateral slips, which, after uniting on the 
dorsal surface of the second phalanx, are con- 
tinued onward, to be inserted into the base of 
the third. [Standing on one foot will show this 
tendon well.] 
Relations.-By its anterior surface with 
the fascia and the annular ligament; by its 
posterior surface with the fibula, interosseous 
membrane, ankle-joint, and Extensor brevis 
digitorum; by its inner side with the Tibialis 
anticus, Extensor proprius pollicis, and ante- 
rior tibial vessels and nerve; by its outer side 
with the Peroneus longus and brevis. 
The Peroneus tertius is a part of the Ex- 
tensor longus digitorum, and might be described 
as its fifth tendon. The fibres belonging to this 
tendon arise from the lower fourth of the ante- 
rior surface of the fibula, from the lower part 
of the interosseous membrane, and from an in- 
termuscular septum between it and the Peroneus brevis. The tendon, after passing 
through the same canal in the annular ligament as the Extensor longus digitorum, 
is inserted into the dorsal surface of the base of the metatarsal bone of the little toe 
on its inner side. This muscle is sometimes wanting. 
Nerves.-These muscles are supplied by the anterior tibial nerve. 
Actions.-The Tibialis anticus and Peroneus tertius are the direct flexors of 
the tarsus upon the leg; the former muscle, from the obliquity in the direction of 
its tendon, raises the inner border of the foot [as in talipes varus] ; and the latter, 
acting with the Peroneus brevis and longus, draws the outer border of the foot 
upward and the sole outward. The Extensor longus digitorum and Extensor pro- 
prius pollicis extend the phalanges of the toes, and, continuing their action, flex the 
tarsus upon the leg. Taking their fixed point from below' in the erect posture, all 
these muscles serve to fix the bones of the leg in the perpendicular position and 
give increased strength to the ankle-joint. 
[Fig. 340. 
A Section of the Right Leg in the Upper Third 
(Heath, from Beraud): 1, Tibialis posticus; 2, 
Tibialis anticus; 3, Flexor longus digitorum ; 
4, Extensor longus digitorum; 5, internal 
saphenous vein; 6, anterior tibial vessels 
and nerve; 7, tendon of Plantaris; 8, Pero- 
neus longus; 9, posterior tibial vessels and 
nerve ; 10, Flexor longus pollicis; 11, external 
saphenous vein and nerve; 12, Soleus with 
fibrous intersection ; 13, peroneal vessels; 14, 
Gastrocnemius (outer half); 15, communi- 
cans peronei nerve.] 
Posterior Tibio-fibular Region. 
Dissection (Fig. 337).-Make a vertical incision along the middle line of the back of the leg 
from the lower part of the popliteal space to the heel, connecting it below by a transverse incis- 
ion extending between the two malleoli; the flaps of integument being removed, the fascia and 
muscles should be examined. 482 
MUSCLES AND FASCIAE. 
The muscles in this region of the leg are subdivided into two layers, superficial 
and deep. The superficial layer constitutes a 
powerful muscular mass, forming the calf of 
the leg. Their large size is one of the most 
characteristic features of the muscular appa- 
ratus in man, and bears a direct connection 
with his ordinary attitude and mode of pro- 
gression. 
Fig. 341. 
Superficial Layer. 
Gastrocnemius. 
Soleus. 
Plantaris. 
The Gastrocnemius is the most superficial 
muscle and forms the greater part of the calf. 
It arises by two heads, which are connected to 
the condyles of the femur by two strong flat 
tendons. The inner head, the larger and a lit- 
tle the more posterior, arises from a depression 
at the upper and back part of the inner con- 
dyle. The outer head arises from the upper 
and back part of the external condyle immedi- 
ately above the origin of the Popliteus. Both 
heads also arise by a few tendinous and fleshy 
fibres from the ridges which are continued up- 
ward from the condyles to the linea aspera. 
Each tendon spreads out into an aponeurosis, 
which covers the posterior surface of that por- 
tion of the muscle to which it belongs, that 
covering the inner head being longer and 
thicker than the outer. From the anterior 
surface of these tendinous expansions muscular 
fibres are given off. The fibres in the median 
line, which correspond to the accessory portions 
of the muscle derived from the bifurcations of 
the linea aspera, unite at an angle upon a me- 
dian tendinous raphe below; the remaining 
fibres converge to the posterior surface of. an 
aponeurosis which covers the under surface of 
the muscle, and this, gradually contracting, 
unites with the tendon of the Soleus and forms 
with it the tendo Achillis. 
Relations.-By its superficial surface with 
the fascia of the leg, which separates it from the 
external saphenous vein and nerve; by its deep 
surface with the posterior ligament of the knee- 
joint, the Popliteus, Soleus, Plantaris, popliteal 
vessels, and internal popliteal nerve. The ten- 
don of the inner head corresponds with the back 
part of the inner condyle, from which it is sep- 
arated by a synovial bursa which in some cases 
communicates with the cavity of the knee-joint. 
The tendon of the outer head contains a sesamoid fibro-cartilage (rarely osseous) 
where it plays over the corresponding outer condyle, and one is occasionally found 
in the tendon of the inner head. 
The Gastrocnemius should be divided across just below its origin, and turned downward in 
order to expose the next muscles. 
rpLBXOn LOHCUS POIXICIO 
i FLEKOK LONCUS DICITOXBH 
Ll 1 '.TIBIALIS POSTICUS 
=-1 o-n s of 
PJUONUC LONCUS « OREVIS 
(Tendons of 
Muscles of the Baek of the Leg, superficial 
layer. POSTERIOR TIBIO-FIBULAR REGION. 
483 
The Soleus is a broad flat muscle situated immediately beneath the preceding. 
It has received its name from its resemblance in shape to a sole-fish. It arises by 
tendinous fibres from the back part of the head of the fibula and from the upper 
third of the posterior surface of its shaft, from the oblique line of the tibia, and 
from the middle third of its internal border; some fibres also arise from a ten- 
dinous arch placed between the tibial and fibular origins of the muscle, beneath 
which the posterior tibial vessels and nerve pass. The fibres pass backward to an 
aponeurosis which covers the posterior surface of the muscle, and this, gradually 
becoming thicker and narrower, joins with the tendon of the Gastrocnemius and 
'forms with it the tendo Achillis. 
Relations.-By its superficial surface with the Gastrocnemius and Plantaris; 
by its deep surface with the Flexor longus digitorum, Flexor longus pollicis, Tibia- 
lis posticus, and posterior tibial vessels and nerve, from which it is separated by the 
transverse intermuscular septum or deep transverse fascia of the leg. 
The Tendo Achillis, the common tendon of the Gastrocnemius and Soleus, is 
the thickest and strongest tendon in the body. It is about six inches in length, 
and formed by the junction of the aponeurosis of the two preceding muscles. It 
commences about the middle of the leg, but receives fleshy fibres on its anterior 
surface nearly to its lower end. Gradually becoming contracted below, it is inserted 
into the lower part of the posterior surface of the os calcis, a synovial bursa [Fig. 
277, p. 357] being interposed between the tendon and the upper part of the tube- 
rosity. The tendon spreads out somewhat at its lower end, so that its narrowest 
part is usually about an inch and a half above its insertion. The tendon is covered 
by the fascia and the integument, and is separated from the deep muscles and vessels 
by a considerable interval filled up with areolar and adipose tissue. Along its outer 
side, but superficial to it, is the external saphenous vein. [This tendon can be well 
studied in almost any position of the leg: standing on tip-toe makes it most tense 
and prominent. It is made concave posteriorly by the posterior annular ligament. 
The model, standing on tip-toe, shows both the large muscles of the calf, so that 
they can be differentiated. The two bellies of the Gastrocnemius can be distin- 
guished, and their difference of development and level well seen, the inner one 
being the stouter and longer. The Soleus shows on both sides, its fibres extending 
down far below those of the Gastrocnemius.] 
The Plantaris is an extremely diminutive muscle placed between the Gastro- 
cnemius and Soleus, and remarkable for its long and delicate tendon. It arises 
from the lower part of the outer bifurcation of the linea aspera and from the pos- 
terior ligament of the knee-joint. It forms a small fusiform belly about three or 
four inches in length, terminating in a long slender tendon which crosses obliquely 
between the two muscles of the calf, and, running along the inner border of the 
tendo Achillis, is inserted with it into the posterior part of the os calcis. This 
muscle is occasionally double, and is sometimes wanting. Occasionally, its tendon 
is lost in the internal annular ligament or in the fascia of the leg. 
Nerves.-These muscles are supplied by the internal popliteal nerve. 
Actions.-The muscles of the calf possess great power, and are constantly 
called into use in standing, walking, dancing, and leaping; hence the large size 
they usually present. In walking, these muscles draw powerfully upon the os calcis, 
raising the heel, and with it the entire body, from the ground; the body being thus 
supported on the raised foot, the opposite limb can be carried forward. In stand- 
ing, the Soleus, taking its fixed point from below, steadies the leg upon the foot 
and prevents the body from falling forward, to which there is a constant tendency 
from the superincumbent weight. The Gastrocnemius, acting from below, serves to 
flex the femur upon the tibia, assisted by the Popliteus. The Plantaris is the rudi- 
ment of a large muscle which exists in some of the lower animals and serves as a 
tensor of the plantar fascia. 484 
MUSCLES AND FASCIAE. 
Deep Layer. 
Popliteus. 
Flexor longus pollicis. 
Flexor longus digitorum. 
Tibialis posticus. 
Dissection.-Detach the Soleus from its attachment to the fibula 
and tibia, and turn it downward, when the deep layer of muscles is 
exposed, covered by the deep transverse fascia of the leg. 
The Deep Transverse Fascia of the leg is a broad, 
transverse, intermuscular septum interposed between the 
superficial and deep muscles in the posterior tibio-fibular 
region. On each side it is connected to the margins of the 
tibia and fibula. Above, where it covers the Popliteus, it 
is thick and dense, and receives an expansion from the 
tendon of the Semimembranosus ; it is thinner in the mid- 
dle of the leg; but below, where it covers the tendons pass- 
ing behind the malleoli, it is thickened. It is continued 
onward in the interval between the ankle and the heel, 
where it covers the vessels, and is blended with the inter- 
nal annular ligament. 
This fascia should now be removed, commencing from below 
opposite the tendons, and detaching it from the muscles in the 
direction of their fibres. 
The Popliteus is a thin, flat, triangular muscle 
which forms part of the floor of the popliteal space, 
and is covered by a tendinous expansion derived from 
the Semimembranosus muscle. It arises by a strong 
flat tendon about an inch in length from a deep depres- 
sion on *the outer side of the external condyle of the 
femur and from the posterior ligament of the knee-joint, 
and is inserted into the inner two-thirds of the triangu- 
lar surface above the oblique line on the posterior sur- 
face of the shaft of the tibia, and into the tendinous 
expansion covering the surface of the muscle. The 
tendon of the muscle is covered by that of the Biceps 
and the external lateral ligament of the knee-joint; it 
grooves the outer surface of the external semilunar 
cartilage, and is invested by the synovial membrane 
of the knee-joint. 
Relations.-By its superficial surface with the 
fascia above mentioned, which separates it from the 
Gastrocnemius, Plantaris, popliteal vessels, and inter- 
nal popliteal nerve; by its deep surface with the 
superior tibio-fibular articulation and back of the 
tibia. 
The Flexor longus pollicis is situated on the 
fibular side of the leg, and is the most superficial 
and largest of the three next muscles. It arises 
from the lower two-thirds of the posterior surface of 
the shaft of the fibula, with the exception of an inch 
at its lowest part; from the lower part of the inter- 
osseous membrane; from an intermuscular septum be- 
tween it and the Peronei externally; and from the 
fascia covering the Tibialis posticus. The fibres pass 
obliquely downward and backward, and terminate round 
a tendon which occupies nearly the whole length of the 
posterior surface of the muscle. This tendon passes 
through a groove on the posterior surface of the tibia external to that for the Tibi- 
Fig. 342. 
Muscles of the Back of the Leg, 
deep layers. POSTERIOR TIBIO-FIBULAR REGION. 
485 
alis posticus and Flexor longus digitorum; it then passes through another groove 
on the posterior surface of the astragalus, and along a third groove, beneath the 
lesser process of the os calcis, into the sole of the foot, where it runs forward be- 
tween the two heads of the Flexor brevis pollicis, and is inserted into the base of 
the last phalanx of the great toe. The grooves in the astragalus and os calcis which 
contain the tendon of the muscle are converted by tendinous fibres into distinct 
canals lined by synovial membrane; and as the tendon crosses the sole of the foot 
it is connected to the common flexor by a tendinous slip. 
Relations.-By its superficial surface with the Soleus and tendo Achillis, from 
which it is separated by the deep transverse fascia; by its deep surface with the 
fibula, Tibialis posticus, the peroneal vessels, the lower part of the interosseous 
membrane, and the ankle-joint; by its outer border with the Peronei; by its inner 
border with the Tibialis posticus and posterior tibial vessels and nerves. 
The Flexor longus digitorum fperforans') is situated on the tibial side of the leg. 
At its origin it is thin and pointed, but gradually increases in size as it descends. 
It arises from the posterior surface of the shaft of the tibia, immediately below the 
oblique line, to within three inches of its extremity internal to the tibial origin of 
the Tibialis posticus ; some fibres also arise from the intermuscular septum between 
it and the Tibialis posticus. The fibres terminate in a tendon which runs nearly 
the whole length of the posterior surface of the muscle. This tendon passes, behind 
the malleolus, in a groove common to it and the Tibialis posticus, but separated from 
the latter by a fibrous septum, each tendon being contained in a special sheath lined 
by a separate synovial membrane. It then passes obliquely forward and outward 
beneath the arch of the os calcis into the sole of the foot (Fig. 344, p. 491), where, 
crossing superficial to the tendon of the Flexor longus pollicis,1 to which it is con- 
nected by a strong tendinous slip, it becomes expanded, is joined by the Flexor 
accessorius, and finally divides into four tendons, which are inserted into the bases 
of the last phalanges of the four lesser toes, each tendon passing through a fissure in 
the tendon of the Flexor brevis digitorum opposite the middle of the first phalanges. 
Relations.-In the leg, by its superficial surface, with the Soleus and the pos- 
terior tibial vessels and nerve, from which it is separated by the deep transverse 
fascia; by its deep surface with the tibia and Tibialis posticus. In the foot it is 
covered by the Abductor pollicis and Flexor brevis digitorum, and crosses super- 
ficial to the Flexor longus pollicis. 
The Tibialis posticus lies between the two preceding muscles, and is the most 
deeply seated of all the muscles in the leg. It commences above by two pointed 
processes separated by an angular interval, through which the anterior tibial vessels 
pass forward to the front of the leg. It arises from the whole of the posterior sur- 
face of the interosseous membrane, excepting its lowest part; from the posterior sur- 
face of the shaft of the tibia, external to the Flexor longus digitorum, between the 
commencement of the oblique line above and the middle of the external border of 
the bone below; and from the upper two-thirds of the internal surface of the fibula; 
some fibres also arise from the deep transverse fascia and from the intermuscular 
septa separating it from the adjacent muscles on each side. This muscle, in the 
lower fourth of the leg, passes in front of the Flexor longus digitorum, terminates 
in a tendon which passes through a groove behind the inner malleolus with the ten- 
don of that muscle, but enclosed in a separate sheath ; it then passes through another 
sheath over the internal lateral ligament and beneath the inferior calcaneo-scaphoid 
ligament, and is inserted into the tuberosity of the scaphoid and internal cuneiform 
bones. The tendon of this muscle contains a sesamoid bone near its insertion, and 
gives off fibrous expansions, one of which passes backward to the sustentaculum tali 
of the os calcis, others outward to the middle and external cuneiform and cuboid, 
and some forward to the bases of the second, third, and fourth metatarsal bones 
(Fig. 345, p. 492). [The tendon of this muscle can be felt just above its insertion 
on strongly inverting the foot, especially if it be resisted.] 
Relations.-By its superficial surface with the Soleus and Flexor longus digi- 
1 That is, in order of dissection of the sole of the foot. 486 
MUSCLES AND FASCIAE. 
torum, the posterior tibial vessels and nerve, and the peroneal vessels, from which 
it is separated by the deep transverse fascia; by its deep surface with the inter- 
osseous ligament, the tibia, fibula, and ankle-joint. 
Nerves.-The Popliteus is supplied by the internal popliteal nerve ; the remain- 
ing muscles of this group by the posterior tibial nerve. 
Actions.-The Popliteus assists in flexing the leg upon the thigh ; when the leg 
is flexed it will rotate the tibia inward. The Tibialis posticus is a direct extensor 
of the tarsus upon the leg; acting in conjunction with the Tibialis anticus, it turns 
the sole of the foot inward [as in talipes varus], antagonizing the Peroneus longus, 
which turns it outward. The Flexor longus digitorum and Flexor longus pollicis 
are the direct flexors of the phalanges, and, continuing their action, extend the foot 
upon the leg; they assist the Gastrocnemius and Soleus in extending the foot, as in 
the act of walking or in standing on tiptoe. In consequence of the oblique direction 
of the tendon of the long flexor the toes would be drawn inward were it not for the 
Flexor accessorius muscle, which is inserted into the outer side of its tendon and 
draws it to the middle line of the foot during its action. Taking their fixed point 
from the foot, these muscles serve to maintain the upright posture by steadying the 
tibia and fibula perpendicularly upon the ankle-joint. They also serve to raise these 
bones from the oblique position they assume in the stooping posture. 
Fibular Region [Figs. 339, 342, 345 and 278, p 359] 
Peroneus longus. 
Peroneus brevis. 
Dissection.-These muscles are readily exposed by removing the fascia covering their surface, 
from below upward, in the line of direction of their fibres. 
The Peroneus longus is situated at the upper part of the outer side of the leg, 
and is the more superficial of the two muscles. It arises from the head and upper 
two-thirds of the outer surface of the shaft of the fibula, from the deep surface of the 
fascia, and from the intermuscular septa between it and the muscles on the front and 
those on the back of the leg. It terminates in a long tendon which passes behind 
the outer malleolus in a groove common to it and the Peroneus brevis, the groove 
being converted into a canal by a fibrous band and the tendons invested by a com- 
mon synovial membrane; it is then reflected obliquely forward across the outer 
side of the os calcis, being contained in a separate fibrous sheath lined by a pro- 
longation of the synovial membrane from that which lines the groove behind the 
malleolus. Having reached the outer side of the cuboid bone, it runs in a groove 
on the under surface of that bone, which is converted into a canal by the long cal- 
caneo-cuboid ligament, and is lined by a synovial membrane : the tendon then crosses 
obliquely the sole of the foot, and is inserted into the outer side of the base of the 
metatarsal bone of the great toe and the internal cuneiform bone. Occasionally it 
sends a slip to the base of the second metatarsal bone. The tendon changes its 
direction at two points: first, behind the external malleolus; secondly, on the outer 
side of the cuboid bone; in both of these situations the tendon is thickened, and in 
the latter a sesamoid bone is usually developed in its substance. [Standing on one 
leg, the tendon of this muscle can be seen springing into strong relief at the ankle 
as the model strives to maintain his equilibrium and hold the leg in position over 
the foot. Its action in eversion of the foot-sole can be especially well appreciated.] 
Relations.-By its superficial surface with the fascia and integument; by its 
deep surface with the fibula and Peroneus brevis, os calcis, and cuboid bone; by 
its anterior border with an intermuscular septum which intervenes between it and the 
Extensor longus digitorum; by its posterior border with an intermuscular septum 
which separates it from the Soleus above and the Flexor longus pollicis below. 
The Peroneus brevis lies beneath the Peroneus longus, and is shorter and smaller 
than it. It arises from the lower two-thirds of the external surface of the shaft of 
the fibula, internal to the Peroneus longus, and from the intermuscular septa sepa- 
rating it from the adjacent muscles on the front and back part of the leg. The fibres MUSCLES AND FASCIAE OF THE FOOT. 
487 
pass vertically downward and terminate in a tendon which runs in front of that of 
the preceding muscle through the same groove, behind the external malleolus, being 
contained in the same fibrous sheath and lubricated by the same synovial membrane; 
it then passes through a separate sheath on the outer side of the os calcis, above that 
for the tendon of the Peroneus longus, and is finally inserted into the dorsal surface 
of the base of the metatarsal bone of the little toe on its outer side. 
Relations.-By its superficial surface with the Peroneus longus and the fascia 
of the leg and foot; by its deep surface with the fibula and outer side of the 
os calcis. 
Nerves.-The Peroneus longus and brevis are supplied by the musculo-cuta- 
neous branch of the external popliteal nerve. 
Actions.-The Peroneus longus and brevis extend the foot upon the leg in con- 
junction with the Tibialis posticus, antagonizing the Tibialis anticus and Peroneus 
tertius, which are flexors of the foot. The Peroneus longus also everts the sole of 
the foot; hence the extreme eversion occasionally observed in fracture of the lower 
end of the fibula, where that bone offers no resistance to the action of this muscle. 
Taking their fixed point below, the Peronei serve to steady the leg upon the foot. 
This is especially the case in standing upon one leg, when the tendency of the 
superincumbent weight is to throw the leg inward: the Peroneus longus overcomes 
this tendency by drawing on the outer side of the leg, and thus maintains the per- 
pendicular direction of the limb. 
Surgical Anatomy.-The student should now consider the position of the tendons of the 
various muscles of the leg, their relation with the ankle-joint and surrounding blood-vessels, and 
especially their action upon tjie foot, as their rigidity and contraction give rise to one or other 
of the kinds of deformity known as club-foot. The most simple and common deformity, and 
one that is rarely if ever congenital, is the talipes equinus, the heel being raised by rigidity 
and contraction of the Gastrocnemius muscle, and the patient walking upon the ball of the foot. 
In the talipes varus the foot is forcibly adducted and the inner side of the sole raised, sometimes 
to a right angle with the ground, by the action of the Tibialis anticus and posticus. In the 
talipes valgus the outer edge of the foot is raised by the Peronei muscles, and the patient walks 
on the inner ankle. In the talipes calcaneus the toes are raised by the Extensor muscles, the 
heel is depressed, and the patient walks upon it. Other varieties of deformity are met with, as 
the talipes equino-varus, equino-valgus, and calcaneo-valgus, whose names sufficiently indicate 
their nature. Of these, the talipes equino-varus is the most common congenital form : the heel 
is raised by the tendo Achillis, the inner border of the foot drawn upward by the Tibialis anti- 
cus, the anterior two-thirds twisted inward by the Tibialis posticus, and the arch increased by 
the contraction of the plantar fascia, so that the patient walks on the middle of the outer border 
of the foot. Each of these deformities may be successfully relieved (after other remedies fail) by 
division of the opposing tendons and fascia: by this means the foot regains its proper position 
and the tendons heal by the organization of lymph thrown out between the divided ends. The 
operation is easily performed by putting the contracted tendon upon the stretch, and dividing it 
by means of a narrow sharp-pointed knife inserted between it and the skin. 
Muscles and Fascia of the Foot. 
The fibrous bands which bind down the tendons in front of and behind the ankle in their 
passage to the foot should now be examined; they are termed the annular ligaments, and are 
three in number-anterior, internal, and external. 
The Anterior Annular Ligament consists of a superior or vertical portion, 
which binds down the extensor tendons as they descend on the front of the tibia 
and fibula; and an inferior or horizontal portion, which retains them in connection 
with the tarsus, the two portions being connected by a thin intervening layer of 
fascia. The vertical portion is attached externally to the lower end of the fibula, 
internally to the tibia, and above is continuous with the fascia of the leg; it con- 
tains only one synovial sheath, for the tendon of the Tibialis anticus, the other 
tendons, and the anterior tibial vessel and nerve passing beneath it, but without 
any distinct sheath. The horizontal portion is attached externally to the upper 
surface of the os calcis, in front of the depression for the interosseous ligament; 
it passes inward, forming a strong band, which encloses the Peroneus tertius and 
Extensor longus digitorum, which are contained in a single synovial sheath, and 
then divides into two limbs, of which the upper is inserted into the internal malle- 488 
MUSCLES AND FASCINE. 
olus, passing over the Extensor proprius pollicis and vessels and nerve, but enclos- 
ing the Tibialis anticus by a splitting of its fibres. The lower limb is inserted into 
the plantar fascia on the inner side of the foot, and passes over both the tendon of 
the Extensor proprius pollicis and Tibialis anticus and also the vessels and nerve. 
The tendons contained in the horizontal portion of the ligament are enclosed by 
separate synovial sheaths. 
The Internal Annular Ligament is a strong fibrous band which extends from 
the inner malleolus above to the internal margin of the os calcis below, converting 
a series of bony grooves in this situation into osseo-fibrous canals for the passage 
of the tendons of the Flexor muscles and vessels into the sole of the foot. It is 
continuous above with the deep fascia of the leg, below with the plantar fascia and 
the fibres of origin of the Abductor pollicis muscle. The three canals which it 
forms transmit from within outward, first, the tendon of the Tibialis posticus; sec- 
ond, the tendon of the Flexor longus digitorum; then the posterior tibial vessels 
and nerve, which run through a broad space beneath the ligament; lastly, in a 
canal formed partly by the astragalus, the tendon of the Flexor longus pollicis. 
Each of these canals is lined by a separate synovial membrane. 
The External Annular Ligament extends from the extremity of the outer mal- 
leolus to the outer surface of the os calcis: it binds down the tendons of the Peronei 
muscles in their passage beneath the outer ankle. The two tendons are enclosed in 
one synovial sac. 
Dissection of the Sole of the Foot.-The foot should be placed on a high block with the sole 
uppermost, and firmly secured in that position. Carry an incision round the heel and along the 
inner and outer borders of the foot to the great and little toes. This incision should divide the 
integument and thick layer of granular fat beneath until the fascia is visible; the skin and fat 
should then be removed from the fascia in a direction from behind forward, as seen in Fig. 337. 
The Plantar Fascia, the densest of all the fibrous membranes, is of great 
strength, and consists of dense pearly-white glistening fibres, disposed, for the 
most part, longitudinally: it is divided into a central and two lateral portions. 
The central portion, the thickest, is narrow behind and attached to the inner 
tubercle of the os calcis, behind the origin of the Flexor brevis digitorum, and, 
becoming broader and thinner in front, divides near the heads of the metatarsal 
bones into five processes, one for each of the toes. Each of these processes divides 
opposite the metatarso-phalangeal articulation into two slips, which embrace the 
sides of the flexor tendons of the toes, and blends with the sheaths of the tendons 
and laterally with the transverse metatarsal ligament, thus forming a series of arches 
through which the tendons of the short and long flexors pass to the toes. The inter- 
vals left between the five processes allow the digital vessels and nerves and the ten- 
dons of the Lumbricales muscles to become superficial. At the point of division of 
the fascia into processes and slips numerous transverse fibres are superadded, which 
serve to increase the strength of the fascia at this part by binding the processes 
together and connecting them with the integument. The central portion of the 
plantar fascia is continuous with the lateral portions at each side, and sends upward 
into the foot, at their point of junction, two strong vertical intermuscular septa, 
broader in front than behind, which separate the middle from the external and inter- 
nal plantar group of muscles; from these, again, thinner transverse septa are derived, 
which separate the various layers of muscles in this region. The upper surface of 
this fascia gives attachment behind to the Flexor brevis digitorum muscle. 
The lateral portions of the plantar fascia are thinner than the central piece and 
cover the sides of the foot. 
The outer portion covers the under surface of the Abductor minimi digiti; it is 
thick behind, thin in front, and extends from the os calcis forward to the base of 
the fifth metatarsal bone, into the outer side of which it is attached; it is continu- 
ous internally with the middle portion of the plantar fascia, and externally with the 
dorsal fascia. 
The inner portion is very thin, and covers the Abductor pollicis muscle; it is MUSCLES OF THE FOOT. 
489 
attached behind to the internal annular ligament, and is continuous around the side 
of the foot with the dorsal fascia, and externally with the middle portion of the 
plantar fascia. 
Muscles of the Foot. 
These are found in two regions: 1, On the dorsum; 2, on the plantai' surface. 
Extensor brevis digitorum. 
1. Dorsal Region. 
The Fascia on the dorsum of the foot is a thin membranous layer, continuous 
above with the anterior margin of the annular ligament; it becomes gradually lost 
opposite the heads of the metatarsal bones, and on each side blends with the lateral 
portion of the plantar fascia; it forms a sheath for the tendons placed on the dor- 
sum of the foot. On the removal of this fascia the muscles and tendons of the 
dorsal region of the foot are exposed. 
The Extensor brevis digitorum (Fig. 339) is a broad thin muscle which arises 
from the outer side of the os calcis, in front of the groove for the Peroneus brevis; 
from the external calcaneo-astragaloid ligament; and from the horizontal portion 
of the anterior annular ligament. It passes obliquely across the dorsum of the 
foot, and terminates in four tendons. The innermost, which is the largest, is 
inserted into the first phalanx of the great toe, crossing the dorsalis pedis artery; 
the other three, into the outer sides of the long extensoi' tendons of the second, 
third, and fourth toes. 
Relations.-By its superficial surface with the fascia of the foot, the tendons 
of the Extensor longus digitorum and Extensor proprius pollicis; by its deep sur- 
face with the tarsal and metatarsal bones and the Dorsal interossei muscles. 
Nerves.-It is supplied by the anterior tibial nerve. 
Actions.-The Extensor brevis digitorum is an accessory to the long Extensor, 
extending the phalanges of the four inner toes, but acting only on the first phalanx 
of the great toe. The obliquity of its direction counteracts the oblique movement 
given to the toes by the long Extensor, so that, both muscles acting together, the 
toes are evenly extended. [Its tendons can be seen and felt on extending the toes 
strongly.] 
2. Plantar Region. 
The muscles in the plantar region of the foot may be divided into three groups, 
in a similar manner to those in the hand. Those of the internal plantar region are 
connected with the great toe, and correspond with those of the thumb ; those of the 
external plantar region are connected with the little toe, and correspond with those 
of the little finger; and those of the middle plantar region are connected with the 
tendons intervening between the two former groups. But in order to facilitate the 
dissection of these muscles it will be found more convenient to divide them into 
four layers, as they present themselves, in the order in which they are successively 
exposed. 
First Layer. 
Abductor pollicis. 
Flexor brevis digitorum. 
Abductor minimi digiti. 
Dissection.-Remove the fascia on the inner and outer sides of the foot, commencing in front 
over the tendons and proceeding backward. The central portion should be divided transversely 
in the middle of the foot, and the two flaps dissected forward and backward. 
The Abductor pollicis lies along the inner border of the foot. It arises from 
the inner tubercle on the under surface of the os calcis, from the internal annular 
ligament, from the plantar fascia, and from the intermuscular septum between it 
and the Flexor brevis digitorum. The fibres terminate in a tendon which is inserted, 490 
MUSCLES AND FASCIAE. 
together with the innermost tendon of the Flexor brevis pollicis, into the inner side 
of the base of the first phalanx of the great toe. 
Relations.-By its superficial surface with the plantar fascia; by its deep sur- 
face with the Flexor brevis pollicis, the Flexor 
accessorius, and the tendons of the Flexor lon- 
gus digitorum and Flexor longus pollicis, the 
Tibialis anticus and posticus, the plantar ves- 
sels and nerves, and the articulations of the 
tarsus. 
The Flexor brevis digitorum (perforatus) 
lies in the middle of the sole of the foot, im- 
mediately beneath1 the plantar fascia, with 
which it is firmly united. It arises by a nar- 
row tendinous process from the inner tubercle 
of the os calcis, from the central part of the 
plantar fascia, and from the intermuscular sep- 
ta between it and the adjacent muscles. It 
passes forward and divides into four tendons. 
Opposite the middle of the first phalanges each 
tendon presents a longitudinal slit to allow of 
the passage of the corresponding tendon of the 
Flexor longus digitorum ; the two portions form 
a groove for the reception of that tendon. The 
tendon of the short flexor then reunites, and 
immediately divides a second time into two 
processes, which are inserted into the sides of 
the second phalanges. The mode of division 
of the tendons of the Flexor brevis digitorum 
and their insertion into the phalanges is anal- 
ogous to the Flexor sublimis in the hand. 
Relations.-By its superficial surface with 
the plantar fascia; by its deep surface with the 
Flexor accessorius, the Lumbricales, the tendons 
of the Flexor longus digitorum, and the exter- 
nal plantar vessels and nerve, from which it is 
separated by a thin layer of fascia. The outer 
and inner borders are separated from the adja- 
cent muscles by means of vertical prolongations 
of the plantar fascia. 
The Abductor minimi digiti lies along the 
outer border of the foot. It arises by a very 
broad origin from the outer tubercle of the os 
calcis, from the under surface of the os calcis 
in front of both tubercles, from the fore part 
of the inner tubercle, from the plantar fascia 
and the intermuscular septum between it and the Flexor brevis digitorum. Its 
tendon, after gliding over a smooth facet on the under surface of the base of the 
fifth metatarsal bone, is inserted with the short Flexor of the little toe into the 
outer side of the base of the first phalanx of the little toe. 
Relations.-By its superficial surface with the plantar fascia. By its deep sur- 
face with the Flexor accessorius, the Flexor brevis minimi digiti, the long plantar 
ligament, and the tendon of the Peroneus longus. On its inner side are the exter- 
nal plantar vessels and nerve, and it is separated from the Flexor brevis digitorum 
by a vertical septum of fascia. 
[Actions.-The Abductor pollicis does abduct the great toe from the others, but 
its chief action is that of a flexor of the first phalanx, and at the same time it 
Fig. 343. 
Muscles of the Sole of the Foot, first layer. 
1 That is, in the order of dissection of the sole of the foot. MUSCLES OF THE FOOT. 
491 
extends the second. It is practically the most internal Interosseous muscle. The 
Flexor brevis digitorum flexes the second phalanges on the first, and then the first on 
the metacarpal bone. The Abductor minimi digiti is the most external Interosseous 
muscle. It abducts the little toe, but chiefly flexes the first and extends the last 
two phalanges.] 
Dissection.-The muscles of the superficial layer should be divided at their origin, by insert- 
ing the knife beneath each and cutting obliquely backward, so as to detach them from the bone 
[it is better to divide their bellies and leave the attach- 
ments] ; they should then be drawn forward in order 
to expose the second layer, but not cut away at their 
insertion. The two layers are separated by a thin 
membrane, the deep plantar fascia, on the removal 
of which is seen the tendon of the Flexor longus 
digitorum, the Flexor accessorius, the tendon of 
the Flexor longus pollicis, and the Lumbricales. 
The long flexor tendons cross each other at an 
acute angle, the Flexor longus pollicis running 
along the inner side of the foot on a plane superior' 
to that of the Flexor longus digitorum, the direc- 
tion of which is obliquely outward. 
Fig. 344. 
Second Layer. 
Flexor accessorius. 
Lumbricales. 
The Flexor accessorius arises by two 
heads, the inner or larger, which is muscular, 
being attached to the inner concave surface 
of the os calcis and to the calcaneo-scaphoid 
ligament; the outer head, flat and tendinous, 
to the under surface of the os calcis in front 
of its outer tubercle and to the long plantar 
ligament: the two portions join at an acute 
angle, and are inserted into the outer margin 
and upper and under surfaces of the tendon 
of the Flexor longus digitorum, forming a 
kind of groove in which the tendon is 
lodged.1 
Relations.-By its superficial surface 
with the muscles of the superficial layer, from 
which it is separated by the external plantar 
vessels and nerves; by its deep surface with 
the os calcis and long calcaneo-cuboid liga- 
ment. 
The Lumbricales are four small muscles 
accessory to the tendons of the Flexor longus 
digitorum: they arise from the tendons of 
the long Flexor as far back as their angle of 
division, each arising from two tendons ex- 
cept the internal one. Each muscle termi- 
nates in a tendon which passes forward on the inner side of each of the lesser toes, 
and is inserted into the expansion of the long Extensor and base of the first phalanx 
of the corresponding toe. 
[Actions.-The Flexor accessorius corrects the otherwise oblique action of the 
Flexor longus digitorum: this obliquity is a consequence of the heel's preventing 
the median position of the Flexor longus digitorum, as in the hand. The Lumbri- 
cales have the same action as in the hand (p. 457).] 
Muscles of the Sole of the Foot, second layer. 
1 According to Turner, the fibres of the Flexor accessorius end in aponeurotic bands, which con- 
tribute slips to the second, third, and fourth digits. 492 
MUSCLES AND FASCIAE. 
Dissection.-The flexor tendons should be divided at the back part of the foot, and the Flexor 
accessorius at its origin and drawn forward, in order to expose the third layer. 
Third Layer. 
Flexor brevis pollicis. 
Adductor pollicis. 
Flexor brevis minimi digiti. 
Transversus pedis. 
The Flexor brevis pollicis arises by <% pointed tendinous process from the inner 
border of the cuboid bone, from the contiguous portion of the external cuneiform, 
and from the prolongation of the tendon of 
the Tibialis posticus, which is attached to 
that bone. The muscle divides in front 
into two portions, which are inserted into 
the inner and outer sides of the base of the 
first phalanx of the great toe, a sesamoid 
bone being developed in each tendon at its 
insertion. The inner portion of this mus- 
cle is blended with the Abductor pollicis 
previous to its insertion, the outer with the 
Adductor pollicis, and the tendon of the 
Flexor longus pollicis lies in a groove be- 
tween them. 
Relations.-By its superficial surface 
■with the Abductor pollicis, the tendon of 
the Flexor longus pollicis, and plantar fas- 
cia ; by its deep) surface with the tendon of 
the Peroneus longus and metatarsal bone 
of the great toe; by its inner border wfith 
the Abductor pollicis ; by its outer border 
with the Adductor pollicis. 
The Adductor pollicis is a large, thick, 
fleshy mass passing obliquely across the 
foot, and occupying the hollow space be- 
tween the four inner metatarsal bones. It 
arises from the tarsal extremities of the 
second, third, and fourth metatarsal bones, 
and from the sheath of the tendon of the 
Peroneus longus, and is inserted, together 
with the outer portion of the Flexor brevis 
pollicis, into the outer side of the base of 
the first phalanx of the great toe. 
The Flexor brevis minimi digiti lies 
on the metatarsal bone of the little toe, 
and much resembles one of the Interossei. 
It arises from the base of the metatarsal 
bone of the little toe and from the sheath 
of the Peroneus longus; its tendon is in- 
serted into the base of the first phalanx of 
the little toe on its outer side. 
Relations.-By its superficial surface 
with the plantar fascia and tendon of the Abductor minimi digiti; by its deep sur- 
face with the fifth metatarsal bone. 
The Transversus pedis is a narrow, flat, muscular fasciculus stretched trans- 
versely across the heads of the metatarsal bones, between them and the flexor ten- 
dons. It arises from the under surface of the head of the fifth metatarsal bone and 
from the transverse ligament of the metatarsus, and is inserted into the outer side 
of the first phalanx of the great toe, its fibres being blended with the tendon of 
insertion of the Adductor pollicis. 
Fig. 345. 
Muscles of the Sole of the Foot, third layer. MUSCLES OF THE FOOT. 
493 
Relations.-By its under surface with the tendons of the long and short Flex- 
ors and Lumbricales; by its upper surface with the Interossei. 
[Actions.-The Flexor brevis pollicis flexes the first phalanx and extends the 
second. The Adductor pollicis adducts the toe, but more especially, like the Abduc- 
tor, is a flexor and extensor. The Flexor brevis minimi digiti flexes and extends 
the phalanges like the Flexor brevis pollicis. The Transversus pedis increases the 
lateral arch of the foot and abducts the great toe.] 
Four th Layer. 
The Interossei. 
The Interossei muscles in the foot are similar to those in the hand, with this 
exception, that they are grouped around the middle line of the second toe, instead 
of the middle line of the whole member, as in the hand. They are seven in num- 
ber, and consist of two groups, dorsal and plantar. 
The Dorsal Interossei, four in number, are situated between the metatarsal bones. 
They are bipenniform muscles, arising by two heads from the adjacent sides of the 
metatarsal bones, between which they are placed; their tendons are inserted into the 
bases of the first phalanges and into the aponeurosis of the common extensor tendon. 
In the angular interval left between the heads of each muscle at its posterior extrem- 
Fig. 346. 
Fig. 347. 
The Dorsal Interossei, left foot. 
The Plantar Interossei, left foot. 
ity the perforating arteries pass to the dorsum of the foot, except in the first Inter- 
osseous muscle, where the interval allows the passage of the communicating branch 
of the dorsalis pedis artery. The first Dorsal interosseous muscle is inserted into the 
inner side of the second toe; the other three are inserted into the outer sides of the 
second, third, and fourth toes. They are all abductors from the middle line of the 
second toe. 
The Plantar Interossei, three in number, lie beneath, rather than between, the 
metatarsal bones. They are single muscles, and are each connected with but one 
metatarsal bone. They arise from the base and inner sides of the shaft of the third, 
fourth, and fifth metatarsal bones, and are inserted into the inner sides of the bases 494 
MUSCLES AND FASCIAE. 
of the first phalanges of the same toes, and into the aponeurosis of the common 
extensor tendon. These muscles are all adductors toward the middle line of the 
second toe. 
Nervous Supply.-The Flexor brevis digitorum, the Flexor brevis and Abduc- 
tor pollicis, and the two inner Lumbricales are supplied by the internal plantar nerve; 
all the other muscles in the sole of the foot by the external plantar. 
[Actions.-The action of the Interosseous muscles of the foot is precisely sim- 
ilar to those of the hands (p. 457). Many of these muscles of the foot act together, 
producing very complex results. 
The student who desires to study the action of most of the muscles of the body 
exhaustively is especially referred to Duchenne's work, Physiologie des MouvementsJ] 
SURGICAL ANATOMY. 
The student should now consider the effects produced by the action of the various muscles in 
fractures of the bones of the lower extremity. The more common forms of fracture are selected 
for illustration and description. 
Fracture of the neck of the femur internal to the capsular ligament (Fig. 348) is a very com- 
mon accident, and is most frequently caused by [slight] indirect violence, such as slipping off the 
edge of the curbstone [tripping on the carpet, etc.], the impetus and weight of the body falling 
upon the neck of the bone. It usually occurs in females, and seldom under fifty years of age. 
At this period of life the cancellous tissue of the neck of the bone not unfrequently is atrophied, 
becoming soft and infiltrated with fatty matter • the compact tissue is partially absorbed ; hence 
the bone is more brittle and more liable to fracture. The characteristic marks of this accident 
are slight shortening of the limb and eversion of the foot, neither of which symptoms occurs, how- 
ever, in some cases until some time after the injury. The 
eversion is caused by the combined action of the external rotator 
muscles, as well as by the Psoas and Iliacus, Pectineus, Ad- 
ductors, and Glutei muscles. The shortening is produced by 
the action of the Glutei and by the Rectoris femoris in front, 
and the Biceps, Semitendinosus, and Semimembranosus behind. 
Fig. 349. 
Fig. 348. 
-PYRIF0BM1S 
-GEMELLUS SUPERIOR 
-OBTURATOR. INTERNUB 
-GEMELLUS INFERIOR 
-OBTURATOR EXJTERNUS 
-QUADRATUS FEMORIB ' 
-«MJ-MEM BRAN, 
•SEMI" KUDIN. 
Fracture of the Neck of the Femur within the Capsular Ligament. 
Fracture of the Femur below the 
Trochanters. 
Fracture of A\c femur just below the trochanters (Fig. 349) is an accident of not unfrequent 
Occurrence, and is attended with great displacement, producing considerable deformity. The SURGICAL ANATOMY. 
495 
npper fragment, the portion chiefly displaced, is tilted forward almost at right angles with the 
pelvis by the combined action of the Psoas and Iliacus, and at the same time everted and drawn 
outward by the External rotator and Glutei muscles, causing a marked prominence at the upper 
and outer side of the thigh, and much pain from the bruising and laceration of the muscles. The 
limb is shortened in consequence of the lower fragment being drawn upward by the Rectus in 
front and the Biceps, Semimembranosus, and Semitendinosus behind ; at the same time the 
lower fragment is everted and its upper end thrown outward and its lower inward, by the Pec- 
tineus and Adductor [and inner hamstring] muscles. This fracture may be reduced in two differ- 
ent methods: either by direct relaxation of all the opposing muscles, to effect which the limb 
should be placed on a double inclined plane, or by overcoming the contraction of the muscles by 
continued extension, which may be effected by means of the long splint. 
Oblique fracture of the femur immediately above the condyles (Fig. 350) is a formidable injury 
and attended with considerable displacement. On examination of the limb the lower fragment 
may be felt deep in the popliteal space, being drawn backward by the Gastrocnemius and Plan- 
taris muscles, and upward by the Posterior femoral [i. e. hamstring] and Rectus muscles. The 
pointed end of the upper fragment is drawn inward by the Pectineus and Adductor muscles, 
and tilted forward by the Psoas and Iliacus, piercing the Rectus muscle, and occasionally the 
integument. Relaxation of these muscles and direct approximation of the broken fragments are 
effected by placing the limb on a double inclined plane. The greatest care is requisite in keeping 
the pointed extremity of the upper fragment in proper position • otherwise, after union of the 
fracture the power of extension of the limb is partially destroyed, from the Rectus muscle being 
held down by the fractured end of the bone, and from the patella, when elevated, being drawn 
upward against the projecting fragment. 
Fracture of the patella (Fig. 351) may be produced by muscular action or by direct violence. 
When produced by muscular action, it occurs thus: A person in danger of falling forward attempts 
to recover himself by throwing the body backward, and the vio- 
lent action of the Quadriceps extensor upon the patella fractures 
the bone transversely. The upper fragment is drawn up the 
thigh by the Quadriceps extensor, 
the lower fragment being retained in 
its position by the ligamentum patel- 
lae, the extent of separation of the two 
fragments depending upon the degree 
of laceration of the ligamentous struc- 
tures around the bone. The patient is 
totally unable to straighten the limb, 
the prominence of the patella is lost, 
and a marked but varying interval can 
be. felt between the fragments. The 
treatment consists in relaxing the op- 
posing muscles, which may be effected 
by raising the trunk and slightly ele- 
vating the limb, which should be kept 
in a straight position. Union is usually 
ligamentous. [The present trend of 
surgical experience is toward the view 
that in many cases operative interfer- 
ence by opening the joint and uniting 
the fragments by sutures is best, and 
gives true bony union. Malgaigne's 
hooks are also often used.] In frac- 
ture from direct violence the bone is 
generally comminuted or fractured 
obliquely or perpendicularly. 
Oblique fracture of the shaft of the tibia (Fig. 352) [is a very common accident, and] usually 
occurs at the lower fourth of the bone, this being the narrowest and weakest part, and is usually 
accompanied by fracture of the fibula. If the fracture has taken place obliquely from above, 
downward and forward, the fragments ride over one another, the lower fragments being drawn 
backward and upward by the powerful action of the muscles of the calf: the pointed extremity 
of the upper fragment projects forward immediately beneath the integument, often protruding 
through it and rendering the fracture a compound one. If the direction of the fracture is the 
reverse of that shown in the figure, the pointed extremity of the lower fragment projects forward, 
riding upon the lower end of the upper one. By bending the knee, which relaxes the opposing 
muscles, and making the extension from the knee and ankle, the fragments may be brought into 
apposition. It is often necessary, however, in compound fracture to remove a portion of the pro- 
jecting bone with the saw before complete adaptation can be effected. 
Fracture of the fibula with dislocation of the foot outward (Fig. 353), commonly known as 
" Pott's fracture," is one of the most frequent injuries of the ankle-joint. The end of the tibia 
is displaced from the corresponding surface of the astragalus, the internal lateral ligament is 
ruptured, and the inner malleolus projects inward beneath the integument, which is tightly 
stretched over it and in danger of bursting. The fibula is broken, usually from two to three 
Fig. 350. 
Fig. 351. 
Fracture of the Patella. 
Fracture of the Femur above 
the Condyles. 496 
MUSCLES AND FASCIAE. 
inches above the ankle, and occasionally that portion of the tibia with which it is more directly 
connected below : the foot is everted by the action of the Pero- 
neus longus, its inner border resting upon the ground, and at 
the same time the heel is drawn up by the muscles of the calf. 
This injury may be at once reduced by flexing the leg at right 
angles with the thigh, which relaxes all the opposing mus- 
cles, and by making slight extension from the knee and ankle. 
[In many cases comparatively little lateral displacement takes 
place, and the fracture is only to be diagnosticated by a widen- 
ing of the intermalleolar space, and sometimes by crepitus. 
(See a paper by the American Editor in the Phila. Med. Times, 
Aug. 15, 1872).] 
Fig. 352. 
Fig. 353. 
Oblique Fracture of the Shaft of the 
Tibia. 
Fracture of the Fibula, with Dislocation of the Foot 
outward-" Pott's fracture." 
[The Action of Individual Muscles, as shown by Electricity. 
The following figures from Von Ziemssen show the chief motor points at which an electrode 
should be applied in order to induce contraction of the various muscles. 
[Fig. 354.] 
Diagram of the Motor Points of the Face, 
showing the position of the electrodes dur- 
ing electrization of special muscles and 
nerves. The anode is supposed to be placed 
in the mastoid fossa, and the cathode upon 
the part indicated in the diagram : 1, Occip- 
ito frontalis (ant. belly); 2, Corrugator super- 
cilii; 3, Occipito frontalis (post, belly); 4, Or- 
bicularis palpebrarum; 5, Retrahens and At- 
tolens aurem; 6, Pyramidalis nasi; 7, facial 
nerve ; 8, Lev. lab. 'sup. et also nasi; 9, Stylo- 
hyoid ; 10, Lev. lab. sup. propr.; 11, Digastric; 
12', Dilator naris ant.; 13, Buccal branches of 
facial nerve; 14, Dilator naris post.; 15, subcu- 
taneous branch of inferior maxillary nerve, 
16, Zygomat. minor; 17, Splenius capitus; 
18, Zygomat. major; 19, external branch of 
Spinal accessory nerve; 20. Orbicularis oris; 
21, Sterno-mastbid; 22, branch for Levator 
menti and Dep. ang. oris; 23, Sterno-mastoid; 
24, Levator menti; 25, Levator anguli scapulse; 
26, Dep. lab. infer.; 27, phrenic nerve; 28, Dep. 
ang. oris; 29, posterior thoracic nerve to 
Rhomboid muscles; 30, subcutaneous nerves 
of neck; 31, circumflex nerve; 32, Sterno- 
hyoid ; 33, posterior thoracic nerve to Serratus 
magnus; 34, Omo-hyoid; 36, Sterno-thyroid; 
38, branch for Platysma; 40, Sterno-hyoid; 
42, Omo-hyoid; 44,46, nerves to Pectoral mus- 
cles.] 
■2 
4 
6 
8 
10 
12 
1 t 
16 
18 
20 
22 
24 
26 
28 
30 
32 
34 
36 
38 
40 
42 
44 
46 
.1 
.3 
. 5 
.7 
-9 
-11 
'13 
-15 
-17 
■19 
-21 
-23 
-25 
-27 
-29 
-31 
-33 APPLICATION OF ELECTRICITY TO THE MUSCLES. 
497 
[Fig. 355.] 
Serratus magnus. 
Latissimus dorsi. 
Intercostal nerves. 
Rectus abdominis. 
Intercostal nerves. 
Transversus 
abdominis. 
[Fig. 356.] 
[Fig. 357.] 
1- 
2- 
3- 
4,x 
5 - 
6- 
2 4 6 3 10 12 
[Fig. 356.-1, External head of Triceps; 2, musculo-spiral nerve; 3, Brachialis anticus: 4, Supinator longus; 
5, Extensor carpi radialis longior; 6, Extensor carpi radialis brevier.] 
[Fig. 357.-1, Musculo-cutaneous nerve; 2, musculo-cutaneous nerve; 3, Biceps; 4, internal head of Triceps; 
6, median nerve; 8, Brachialis anticus; 10, ulnar nerve; 12, branch of median nerve to the Pronator teres.] 498 
MUSCLES AND FASCIAE. 
[Fig. 358.] 
[Fig. 359.] 
2 
4 
6 
8 
10 
12 
14 
16 
18 
20 
22 
24 
4- 
6 
8 
10- 
12 
14. 
16 
18- 
1- 
20 2- 
3 ' 
-1 
.3 
.5 
- 7 
-9 
.11 
- 13 
- 15 
■ 17 
- 19 
1 
3 
5 
7 
9 
11 
[Fig. 358.-1, Flexor carpi radialis; 2, branch of the median nerve for the Pronator teres; 3, Flexor profundus 
digitorum; 4, Palmaris longus; 5, Flexor sublimis digitorum ; 6, Flexor carpi ulnaris: 7, Flexor longus polli- 
cis ; 8, Flexor sublimis digitorum (middle and ring fingers); 9, median nerve; 10, ulnar nerve; 11, Abductor 
pollicis; 12, Flexor sublimis digitorum (index and little finger); 13, Opponens pollicis; 14, deep branch of 
ulnar nerve; 15, Flexor brevis pollicis; 16, Palmaris brevis; 17, Adductor pollicis, 18, Abductor minimi 
digiti; 19, Lumbricalis (1st); 20, Flexor brevis minimi digiti; 22, Opponens minimi digiti; 24, Lumbricales 
(2, 3, and 4).] 
[Fig. 359.-1, Extensor carpi ulnaris; 2, Supinator longus ; 3, Extensor minimi digiti; 4, Extensor carpi radialis 
longior; 5, Extensor indicis: 6, Extensor carpi radialis brevior; 7, Extensor secundi internodii pollicis; 8, 
Extensor communis digitorum; 9, Abductor minimi digiti; 10, Extensor indicis; 11, Dorsal interosseus (4); 
12, Extensor indicis and Extensor ossis metacarpi pollicis; 14, Extensor ossis metacarpi pollicis; 16, Exten- 
sor primi internodii pollicis; 18, Flexor longus pollicis; 20, dorsal Interossei.] application of electricity to the muscles. 
499 
[Fig. 360.] 
[Fig. 361.1 
.. 1 
.- 3 
-5 
■ 7 
- 9 
2 . 
4 - 
6 
8 . 
10 • 
12 . 
14 • 
2 
4 . 
6 • 
8 
10 - 
12 - 
14 • 
16 • 
1 
. 3 
• 5 
7 
[Fig. 360.-1, Tensor vaginae femoris (branch of superior gluteal nerve); 2, anterior crural nerve; 3, Tensol- 
vaginae femoris (branch of crural nerve); 4, obturator nerve; 5, Rectus femoris; 6, Sartorius; 7, Vastus 
externus; 8, Adductor longus ; 9, Vastus externus; 10, branch of crural nerve to Quadriceps extensor cruris; 
12, Crureus; 14, branch of crural nerve, to Vastus externus.] 
[Fig. 361.-1, Adductor magnus; 2, inferior gluteal nerve for Gluteus maximus; 3, Semitendinosus; 4, great sciatic 
nerve; 5, Semimembranosus; 6, long head of Biceps; 7, Gastrocnemius (internal head); 8, short head of 
Biceps; 10, posterior tibial nerve; 12, peroneal nerve; 14, Gastrocnemius (external head); 16, Soleus.] 500 
MUSCLES AND FAS CUE. 
[Fig. 362.] 
[Fig. 363.] 
■1 
- 3 
• 5 
- 7 
• 9 
• 11 
13 
15 
17 
2 
4 
6 
8 
10 
1.. 
2 - 
3- 
4... 
5 ..J 
[Fig. 362.-1, Peroneal nerve; 2, Peroneus longus; 3, Gastrocnemius (external head); 4, Tibialis anticus; 5, Soleus; 
6, Extensor longus pollicis; 7, Extensor communis digitorum longus; 8, branch of peroneal nerve for Exten- 
sor brevis digitorum; 9, Peroneus brevis; 10, dorsal Interossei; 11, Soleus; 13, Flexor longus pollicis; 
15, Extensor brevis digitorum; 17, Abductor minimi digit!.] 
[Fig. 363.-1, Gastrocnemius (internal head); 2, Soleus; 3, Flexor communis digitorum longus; 4, posterior tibial 
nerve; 5, Abductor pollicis.] Of the Arteries. 
THE Arteries are cylindrical tubular vessels which serve to convey blood from 
both ventricles of the heart to every part of the body. These vessels were 
named "arteries" air; Typetv, to contain) from the belief entertained by 
the ancients that they contained air. To Galen is due the honor of refuting this 
opinion; he showed that these vessels, though for the most part empty after death, 
contain blood in the living body. 
The pulmonary artery, which arises from the right ventricle of the heart, carries 
venous blood directly into the lungs, wdience it is returned by the pulmonary veins 
into the left auricle. This constitutes the lesser or pulmonic circulation. The great 
artery, which arises from the left ventricle, the aorta, conveys arterial blood to the 
body generally, whence it is brought back to the right side of the heart by means 
of the veins. This constitutes the greater or systemic circulation. 
The distribution of the systemic arteries is like a highly ramified tree, the com- 
mon trunk of which, formed by the aorta, commences at the left ventricle of the 
heart, the smallest ramifications corresponding to the circumference of the body 
and the contained organs. The arteries are found in every part of the body with 
the exception of the hairs, nails, epidermis, cartilages, and cornea, and the larger 
trunks usually occupy the most protected situations, running in the limbs along the 
flexor side, where they are less exposed to injury. 
There is considerable variation in the mode of division of the arteries: occa- 
sionally a short trunk subdivides into several branches at the same point, as we 
observe in the coeliac and thyroid axes; or the vessel may give off several branches 
in succession, and still continue as the main trunk, as is seen in the arteries of the 
limbs; but the usual division is dichotomous-as, for instance, the aorta, divid- 
ing into the two common iliacs; and the common carotid, into the external and 
internal. 
The branches of arteries arise at very variable angles: some, as the superior 
intercostal arteries from the aorta, arise at an obtuse angle; others, as the lumbar 
arteries, at a right angle; or, as the spermatic, at an acute angle. An artery from 
which a branch is given off is smaller in size, but retains a uniform diameter until 
a second branch is derived from it. A branch of an artery is smaller than the 
trunk from which it arises, but if an artery divides into two branches, the com- 
bined area of the two vessels is in nearly every instance somewhat greater than that 
of the trunk, and the combined area of all the arterial branches greatly exceeds the 
area of the aorta; so that the arteries collectively may be regarded as a cone, the 
apex of which corresponds to the aorta, the base to the capillary system. 
The arteries in their distribution communicate freely with one another, forming 
what is is called an anastomosis (d.vd, between ; aTopa. mouth) or inosculation ; and 
this communication is very free between the large as well as between the smaller 
branches. The anastomosis between trunks of equal size is found where great free- 
dom and activity of the circulation are requisite, as in the brain; here the two ver- 
tebral arteries unite to form the basilar, and the two internal carotid arteries are 
connected by a short communicating trunk ; it is also found in the abdomen, the 
intestinal arteries having very free anastomoses between their larger branches. In 
the limbs the anastomoses are most frequent and of largest size around the joints, 
the branches of an artery above freely inosculating with branches from the vessels 
below: these anastomoses are of considerable interest to the surgeon, as it is by 
their enlargement that a collateral circulation is established after the application of 
a ligature to an artery for the cure of aneurism. The smaller branches of arteries 
anastomose more frequently than the larger, and between the smallest twigs these 
501 502 
THE ARTERIES. 
inosculations become so numerous as to constitute a close network that pervades 
nearly every tissue of the body. 
Throughout the body generally the larger arterial branches pursue a perfectly 
straight course, but in certain situations they are tortuous; thus, the facial artery 
in its course over the face, and the arteries of the lips, are extremely tortuous in 
their course to accommodate themselves to the movements of the parts. The ute- 
rine arteries are also tortuous, to accommodate themselves to the increase of size 
which the organ undergoes during pregnancy. Again, the internal carotid and 
vertebral arteries previous to their entering the cavity of the skull describe a series 
of curves which are evidently intended to diminish the velocity of the current of 
blood by increasing the extent of surface over which it moves and adding to the 
amount of impediment which is produced by friction. 
The arteries are dense in structure, of considerable strength, highly elastic, and 
when divided they preserve, although empty, their cylindrical form. 
The minute structure of these vessels is described in the chapter on General 
Anatomy [p. 78], 
In the description of the arteries we shall first consider the efferent trunk of the 
pulmonic circulation, the pulmonary artery, and then the efferent trunk of the sys- 
temic circulation, the aorta and its branches. 
Pulmonary Artery (Fig. 364). 
The Pulmonary Artery conveys the venous blood from the right side of the 
heart to the lungs. It is a short wide vessel, about two inches in length, arising 
from the left side of the base of the right ventricle in front of the aorta. It ascends 
obliquely upward, backward, and to the left side, winding spirally in front of and 
then to the left of the ascending part of the arch of the aorta as far as the under 
surface of the transverse portion of the arch, where it divides into two branches of 
nearly equal size, the right and left pulmonary arteries. 
Relations.-The greater part of this vessel is contained, together with the 
ascending part of the arch of the aorta, in the pericardium, being enclosed with it 
in a tube of serous membrane continued upward from the base of the heart, and has 
attached to it above the fibrous layer of the membrane. Behind it rests at first 
upon the ascending aorta, and higher up lies in front of the left auricle. On either 
side of its origin is the appendix of the corresponding auricle and a coronary artery, 
and higher up it passes to. the left side of the ascending aorta. 
A little to the left of its point of bifurcation it is connected to the under surface 
of the arch of the aorta by a short fibrous cord, the remains of a vessel peculiar to 
foetal life, the ductus arteriosus. 
The Right Pulmonary Artery, longer and larger than the left, runs horizon- 
tally outward, behind the ascending aorta and superior vena cava, to the root of 
the right lung, where it divides into two branches, of which the lower, which is the 
larger, supplies the lower lobe, the upper giving a branch to the middle lobe. 
The Left Pulmonary Artery, shorter and somewhat smaller than the right, 
passes horizontally in front of the descending aorta and left bronchus to the root 
of the left lung, where it divides into two branches for the two lobes. 
The terminal branches of the pulmonary artery will be described with the 
anatomy of the Lung. 
The Aorta. 
The Aorta arteria magna) is the main trunk of a series of vessels which, 
arising from the heart, convey the red oxygenated blood to every part of the body 
for its nutrition. This vessel commences at the upper part of the left ventricle, and, 
after ascending for a short distance, arches backward and to the left side over the 
root of the left lung, descends within the thorax on the left side of the vertebral 
column, passes through the aortic opening in the Diaphragm, and, entering the 
abdominal cavity, terminates, considerably diminished in size, opposite the fourth THE AORTA. 
503 
lumbar vertebra, where it divides into the right and left common iliac arteries. 
Hence its subdivision, from the direction or position of its parts, into the arch of 
ThyreiH Gtai'i' 
Fro. 364. 
Xf Vagus 
Recurrent Largugeal 
- ZeftVagus 
- LeflThrenic 
- ThoracicDuot 
Plan of the Branches. 
Fig. 365. 
Recurrent 
-Laryngeal 
R'.Coronary-{ 
Coronary 
The Arch of the Aorta and its Branches. 
the aorta, [and] the descending [aorta, which last is again divided into the] thoracic 
aorta and the abdominal aorta.1 
Arch of the Aorta. 
Dissection.-In order to examine the arch of the aorta, open the thorax by dividing the car- 
tilages of the ribs on each side of the sternum, raising this bone from below upward, and then 
sawing through the sternum on a level with its articulation with the clavicle. By this means 
the relations of the large vessels to the upper border of the sternum and root of the neck are kept 
in view. 
The Arch of the Aorta extends from the origin of the vessel at the upper part 
of the left ventricle to the lower border of the body of the fifth dorsal vertebra. 
At its commencement it ascends behind the sternum obliquely upward and forward 
toward the right side, and opposite the upper border of the second costal cartilage 
1 These portions of the aorta would be better named transverse aorta, dorsal aorta, and abdominal 
or lumbar aorta; but I hesitate to introduce new names in place of those in universal use. 504 
THE ARTERIES. 
of the right side passes transversely, from right to left and from before backward, to 
the left side of the lower border of the fourth dorsal vertebra; it then descends upon 
the left side of the body of the fifth dorsal vertebra, at the lower border of which it 
takes the name of thoracic aorta. The arch of the aorta describes a curve, the con- 
vexity of which is directed upward and to the right side, and it is subdivided at the 
points where it changes its direction so as to be described in three portions-the 
ascending, transverse, and descending portions of the arch of the aorta. 
Ascending Part of the Arch. 
The ascending1 portion of the arch of the aorta is about two inches in length. It 
commences at the upper part of the left ventricle, in front of the left auriculo-vcntric- 
ular orifice, and on a level with the lower border of the third costal cartilage behind 
the centre of the sternum ; it passes obliquely upward, in the direction of the heart's 
axis, to the right side, as high as the upper border of the second right costal carti- 
lage, describing a slight curve in its course, and being situated, when distended, about 
a quarter of an inch behind the posterior surface of the sternum. A little above its 
commencement it is somewhat enlarged, and presents three small dilatations, called 
the sinuses of the aorta (sinuses of Valsalva), opposite to which are attached the 
three semilunar valves, which serve the purpose of preventing any regurgitation of 
blood into the cavity of the ventricle. A section of the aorta opposite this part has 
a somewhat triangular figure, but below the attachment of the valves it is circular. 
This portion of the aorta is contained in the cavity of the pericardium, and, together 
with the pulmonary artery, is invested in a tube of serous membrane continued on 
to them from the surface of the heart. 
Relations.-The ascending part of the arch is covered at its commencement by 
the trunk of the pulmonary artery and the right appendix auriculae, and higher up 
is separated from the sternum by the pericardium, some loose areolar tissue, and the 
remains of the thymus gland; behind it rests upon the right pulmonary vessels and 
root of the right lung. On the right side it is in relation with the superior vena 
cava and right auricle; on the left side, with the pulmonary artery. 
Plan of the Relations of the Ascending Part of the Arch. 
Zn Front. 
Pulmonary artery. 
Right appendix auriculae. 
Pericardium. 
Remains of thymus gland. 
Right Side. 
Superior cava. 
Right auricle. 
Arch of Aorta.' 
Ascending 
Portion. 
Left Side. 
Pulmonary artery. 
Behind. 
Right pulmonary vessels. 
Root of right lung. 
The second or transverse portion of the arch commences at the upper border 
of the second chondro-sternal articulation of the right side, and passes from right to 
left and from before backward, to the left side of the lower border of the fourth dor- 
sal vertebra behind.1 Its upper border is usually about an inch below the upper 
margin of the sternum. 
Transverse Part of the Arch. 
' Mr. J. Wood gives the following account of the relations and extent of the arch of the aorta, as 
the result of his observations on thirty-two subjects, fourteen male and eighteen female, in whom an 
antero-posterior vertical section of the spinal column from top to bottom had been made, with the 
viscera in situ: 
The cardiac opening of the aorta lies in a horizontal plane drawn through the centre of the third 
bone of the sternum, passing midway between the third and fourth rib-cartilages, and emerging behind THE AORTA. 
505 
Relations.-Its anterior surface is covered by the left pleura and lung and 
remains of the thymus gland, and crossed toward the left side by the left pneumo- 
gastric and phrenic nerves and superficial cardiac branches of the left sympathetic, 
and by the left superior intercostal vein. Its posterior surface lies on the trachea, just 
above its bifurcation, on the great or deep cardiac plexus, the oesophagus, thoracic 
duct, and left recurrent laryngeal nerve. Its upper border is in relation with the 
left innominate vein, and from its upper part are given off the innominate, left com- 
mon carotid, and left subclavian arteries. Its lotver border is in relation with the 
bifurcation of the pulmonary artery and the remains of the ductus arteriosus, which 
is connected with the left division of that vessel; the left recurrent laryngeal nerve 
winds round it from before backward, whilst the left bronchus passes below it. 
Plan of the Relations of the Transverse Part of the Arch 
A&ore. 
Left innominate vein. 
Arteria innominata. 
Left carotid. 
Left subclavian. 
In Front. 
Left pleura and lung. 
Remains of thymus gland. 
Left pneumogastric nerve. 
Left phrenic nerve. 
Superficial cardiac nerves. 
Left superior intercostal vein. 
Behind. 
Trachea. 
Deep cardiac plexus. 
(Esophagus. 
Thoracic duct. 
Left recurrent nerve. 
Arch of Aorta.' 
Transverse 
Portion. y 
Below. 
Bifurcation of pulmonary artery. 
Remains of ductus arteriosus. 
Left recurrent nerve. 
Left bronchus. 
Descending Part of the Arch. 
The descending1 portion of the arch has a straight direction, inclining down- 
ward on the left side of the body of the fifth dorsal vertebra, at the lower border 
of which it takes the name of descending thoracic aorta. 
Relations.-Its anterior surface is covered by the pleura and root of the left 
lung; behind it lies on the left side of the body of the fifth dorsal vertebra. On 
its right side are the oesophagus and thoracic duct; on its left side it is covered by 
the pleura. 
Plan of the Relations of the Descending Part of the Arch. 
In Front. 
Pleura. 
Root of left lung. 
Right Side. 
(Esophagus. 
Thoracic duct. 
/Arch of Aorta. 
Descending 
\ Portion. 
Left Side. 
Pleura. 
Behind. 
Left side of body of fifth dorsal vertebra.. 
about the tip of the sixth dorsal spinous process. The highest point of the aortic arch lies from 
three-quarters of an inch to an inch from the posterior surface of the second bone of the sternum, 
close to its right border and to the inner side of the joint between the second right rib-cartilage and 
the sternum. It approaches the lower border of the left side of the fourth dorsal vertebra, and first 
touches the spine usually about the intervertebral substance between the fourth and fifth vertebrae. It 
then assumes a more vertical direction, and lies against the left side of the body of the fifth dorsal 
vertebra, which is, in fact, the uppermost vertebra which shows on its body the impression.or flatten- 
ing produced by contact with the aorta (Journ. of Anat. and Phys.,vol. iii.). 
This description is the one usually accepted, and is supported by the observations of Pirogoff, but 
some anatomists put the two lower portions of the arch one vertebra higher. 506 
THE ARTERIES. 
The ascending, transverse, and descending portions of the arch vary in position 
according to the movements of respiration, being lowered, together with the trachea, 
bronchi, and pulmonary vessels, during inspiration by the descent of the Diaphragm, 
and elevated during expiration, when the Diaphragm ascends. These movements 
are greater in the ascending than the transverse, and in the latter than the descend- 
ing part. 
Peculiarities.-The height to which the aorta rises in the chest is usually about an 
inch below the upper border of the sternum, but it may ascend nearly to the top of that 
bone. Occasionally it is found an inch and a half, more rarely two or even three inches, below 
this point. 
In Direction.-Sometimes the aorta arches over the root of the right instead of the left lung, 
as in birds, and passes down on the right side of the spine. In such cases all the viscera of the 
thoracic and abdominal cavities are transposed. Less frequently, the aorta, after arching over 
the root of the right lung, is directed to its usual position on the left side of the spine, this pecu- 
liarity not being accompanied by any transposition of the viscera. 
In Conformation.-The aorta occasionally divides, as in some quadrupeds, into an ascend- 
ing and a descending trunk, the former of which is directed vertically upward, and subdivides 
into three branches to supply the head and upper extremities. Sometimes the aorta subdivides 
soon after its origin into two branches, which soon reunite. In one of these cases the oesophagus 
and trachea were found to pass through the interval left by their division; this is the normal 
condition of the vessel in the Reptilia. 
Surgical Anatomy.-Of all the vessels of the arterial system, the aorta, and more espe- 
cially its arch, is most frequently the seat of disease ; hence it is important to consider some of 
the consequences that may ensue from aneurism of this part. 
It will be remembered that the ascending part of the arch is contained in the pericardium, 
just behind the sternum, being crossed at its commencement by the pulmonary artery and right 
auricular appendix, and having the root of the right lung behind, the vena cava on the right 
side, and the pulmonary artery and left auricle on the left side. 
Aneurism of the ascending aorta, in the situation of the aortic sinuses, in the great majority 
of cases affects the right anterior sinus ; this is mainly owing to the fact that the regurgitation 
of blood upon the sinuses takes place chiefly on the right anterior aspect of the vessel. As the 
aneurismal sac enlarges it may compress any or all of the structures in immediate proximity with 
it, but chiefly projects toward the right anterior side, and consequently interferes mainly with 
those structures that have a corresponding relation with the vessel. In the majority of cases it 
bursts into the cavity of the pericardium, the patient suddenly drops down dead, and upon a 
post-mortem examination the pericardial sac is found full of blood ; or it may compress the right 
auricle or the pulmonary artery and adjoining part of the right ventricle, and open into one or 
the other of these parts, or may press upon the superior cava. 
Aneurism of the ascending aorta, originating above the sinuses, most frequently implicates the 
right anterior wall of the vessel; this is probably mainly owing to the blood being impelled 
against this part. The direction of the aneurism is also chiefly toward the right of the median 
line. If it attains a large size and projects forward, it may absorb the sternum and the car- 
tilages of the ribs, usually on the right side, and appear as a pulsating tumor on the front of the 
chest, just below the manubrium ; or it may burst into the pericardium, or may compress or open 
into the right lung, the trachea, bronchi, or oesophagus. 
Regarding the transverse part of the arch, the student is reminded that the vessel lies on the 
trachea, the oesophagus, and thoracic duct; that the recurrent laryngeal nerve winds around it; 
and that from its upper part are given off three large trunks, which supply the head, neck, and 
upper extremities. Now, an aneurismal tumor taking origin from the posterior part or right 
aspect of the vessel, its most usual site, may press upon the trachea, impede the breathing, or 
produce cough, haemoptysis, or stridulous breathing, or it may ultimately burst into that tube, 
producing fatal hemorrhage. Again, its pressure on the laryngeal nerves may give rise to 
symptoms which so accurately resemble those of laryngitis that the operation of tracheotomy 
has in some cases been resorted to, from the supposition that disease existed in the larynx ; or it 
may press upon the thoracic duct and destroy life by inanition ; or it may involve the oesophagus, 
producing dysphagia; or it may burst into the oesophagus, when fatal hemorrhage will occur. 
Again, the innominate artery or the left carotid or subclavian may be so obstructed by clots as to 
produce a weakness, or even a disappearance, of the pulse in one or the other wrist; or the tumor 
may present itself at or above the manubrium, generally either in the median line or to the right 
of the sternum, and may simulate an aneurism of one of the arteries of the neck. 
Aneurism affecting the descending part of the arch is usually directed backward and to the 
left side, causing absorption of the vertebra? and corresponding ribs, or it may press upon the 
trachea, left bronchus, oesophagus, and the right and left lungs, generally the latter. When rup- 
ture of the sac occurs, it usually takes place into the left pleural cavity; less frequently into the 
left bronchus, the right pleura, or into the substance of the lungs or trachea. In this form of 
aneurism pain is an almost constant and characteristic symptom, referred to either the back or 
chest, and usually radiating from the spine around the left side. This symptom depends upon 
the aneurismal sac compressing the intercostal nerves against the bone. THE CORONARY ARTERIES. 
507 
Branches of the Arch of the Aorta (Figs. 364, 365). 
The bi'anches given off from the arch of the aorta are five in number: two of 
small size, from the ascending portion, the right and left coronary; and three of 
large size, from the transverse portion, the innominate artery, the left common caro- 
tid, and the left subclavian. 
Peculiarities.-Position of the Branches.-The branches, instead of arising from the 
highest part of the arch (their usual position), may be moved more to the right, arising from the 
commencement of the transverse or upper part of the ascending portion; or the distance from 
one another at their origin may be increased or diminished, the most frequent change in this 
respect being the approximation of the left carotid toward the innominate artery. 
The number of the primary branches may be reduced to two : the left carotid, arising from 
the innominate artery, or (more rarely) the carotid and subclavian arteries of the left side, aris- 
ing from a left innominate artery. But the number may be increased to four, from the right 
carotid and subclavian arteries arising directly from the aorta, the innominate being absent. In 
most of these latter cases the right subclavian has been found to arise from the left end of the 
arch; in other cases it was the second or third branch given off instead of the first. Lastly, the 
number of trunks from the arch may be increased to five or six ; in these instances the external 
and internal carotids arise separately from the arch, the common carotid being absent on one or 
both sides. 
Number Usual, Arrangement Different.-When the aorta arches over to the right 
side, the three branches have an arrangement the reverse of what is usual, the innominate sup- 
plying the left side, and the carotid and subclavian (which arises separately) the right side. In 
other cases, where the aorta takes its usual course, the two carotids may be joined in a common 
trunk, and the subclavians arise separately from the arch, the right subclavian generally arising 
from the left end of the arch. 
Secondary branches sometimes arise from the arch; most commonly such a secondary 
branch is the left vertebral, which usually takes origin between the left carotid and left subcla- 
vian, or beyond them. Sometimes a thyroid branch is derived from the arch or the right inter- 
nal mammary or right vertebral, or, more rarely, both vertebral.1 
The Coronary Arteries. 
The Coronary Arteries supply the heart: they are two in number, right and 
left, arising near the commencement of the aorta immediately above the free mar- 
gin of the semilunar valves. 
The Rig-ht Coronary Artery, about the size of a crow's quill, arises from the 
aorta immediately above the free margin of the right semilunar valve, between the 
pulmonary artery and the right appendix auriculae. It passes forward to the right 
side in the groove between the right auricle and ventricle, and, curving around the 
right border of the heart, runs along its posterior surface as far as the posterior 
interventricular groove, where it divides into two branches, one of which continues 
onward in the groove between the left auricle and ventricle and anastomoses with 
the left coronary; the other descends along the posterior interventricular furrow, 
supplying branches to both ventricles and to the septum, and anastomosing at the 
apex of the heart with the descending branches of the left coronary. 
This vessel sends a large branch along the thin margin of the right ventricle to 
the apex, and numerous small branches to the right auricle and ventricle and the 
commencement of the pulmonary artery. 
The Left Coronary, larger than the former, arises immediately above the free 
edge of the left semilunar valve, a little higher than the right; it passes forward 
between the pulmonary artery and the left appendix auriculae, and descends obliquely 
toward the anterior interventricular groove, where it divides into two branches. Of 
these, one passes transversely outward in the left auriculo-ventricular groove, and 
winds around the left border of the heart to its posterior surface, where it anasto- 
moses with the transverse branch of the right coronary; the other descends along 
the anterior interventricular groove to the apex of the heart, where it anastomoses 
with the descending branches of the right coronary. The left coronary supplies 
1 The anomalies of the aorta and its branches are minutely described by Krause in Henle's 
Anatomy (Brunswick, 1876), vol. iii. p. 210 et seqq. 508 
THE ARTERIES. 
the left auricle and its appendix, both ventricles, and numerous small branches to 
the pulmonary artery and commencement of the aorta.1 
Peculiarities.-These vessels occasionally arise by a common trunk, or their number may 
be increased to three, the additional branch being of small size. More rarely, there are two 
additional branches. 
Arteria Innominata. 
The Innominate Artery (brachio-cephalic) is the largest branch given off 
from the arch of the aorta. It arises from the commencement of the transverse 
portion in front of the left carotid, and, ascending obliquely to the upper border of 
the right sterno-clavicular articulation, divides into the right common carotid and 
right subclavian arteries. This vessel varies from an inch and a half to two inches 
in length. 
Relations.-In front it is separated from the first bone of the sternum by the 
Sterno-hyoid and Sterno-thyroid muscles, the remains of the thymus gland, the left 
innominate and right inferior thyroid veins, which cross its root, and sometimes the 
inferior cervical cardiac branch of the right pneumogastric. Behind it lies upon 
the trachea, which it crosses obliquely. On the right side is the right vena innom- 
inata, right pneumogastric nerve, and the pleura; and on the left side the remains 
of the thymus gland and origin of the left carotid artery. 
Plan of the Relations of the Innominate Artery. 
Zn Front. 
Sternum. 
Sterno-hyoid and Sterno-thyroid muscles. 
Remains of thymus gland. 
Left innominate and right inferior thyroid veins. 
Inferior cervical cardiac branch from right pneumogastric nerve, 
Right Side. 
Right vena innominata. 
Right pneumogastric nerve. 
Pleura. 
Left Side. 
Remains of thymus. 
Left carotid. 
Innominate 
Artery. 
Behind. 
Trachea. 
Branches.-The innominate usually gives off no branches, but occasionally a 
small branch, the thyroidea ima, is given off' from this vessel. It ascends in front 
of the trachea to the lower part of the thyroid body, which it supplies. It varies 
greatly in size, and appears to compensate for deficiency or absence of one of the 
other thyroid vessels. It occasionally is found to arise from the subclavian or inter- 
nal mammary vessel. The innominate artery also sometimes gives off a thymic or 
bronchial branch. 
Peculiarities in Point of Division.-When the bifurcation of the innominate artery 
varies from the point above mentioned, it sometimes ascends a considerable distance above the 
sternal end of the clavicle; less frequently it divides below it. In the former class of cases its 
length may exceed two inches, and in the latter be reduced to an inch or less. These are points 
of considerable interest for the surgeon to remember in connection with the operation of tying 
this vessel. 
Position.-When the aorta arches over to the right side the innominate is directed to the 
left side of the neck instead of the right. 
Collateral Circulation.-Allan Burns demonstrated on the dead subject the possibility 
of the establishment of the collateral circulation after ligature of the innominate artery, by tying 
and dividing that artery, after which, he says, " even coarse injection impelled into the aorta 
passed freely by the anastomosing branches into the arteries of the right arm, filling them and 
all the vessels of the head completely" {Surgical Anatomy of the Head and Neck, p. 62). The 
1 According to Dr. Samuel West, there is a very free and complete anastomosis between the two 
coronary arteries (Lancet, June 2, 1883, p. 945). COMMON CAROTID ARTERIES. 
509 
branches by which this circulation would be carried on are very numerous; thus, all the com- 
munications across the middle line between the branches of the carotid arteries of opposite sides 
would be available for the supply of blood to the right side of the head and neck, while the anas- 
tomosis between the superior intercostal of the subclavian and the first aortic intercostal (see infra 
on the collateral circulation after obliteration of the thoracic aorta) wmuld bring the blood, by a 
free and direct course, into the right subclavian: the numerous connections also between the 
lower intercostal arteries and the branches of the axillary and internal mammary arteries would 
doubtless assist in the supply of blood to the right arm, while the epigastric, from the external 
iliac, would, by means of its anastomosis with the internal mammary, compensate for any defi- 
ciency in the vascularity of the wall of the chest. 
Surgical Anatomy.-Although the operation of tying the innominate artery has been 
performed by several surgeons for aneurism of the right subclavian extending inward as far as 
the Scalenus, in only one instance has it been attended with success.1 Mott's patient, however, 
on whom the operation was first performed, lived nearly four weeks, and Graefe's more than two 
months. The main obstacles to the operation are, as the student will perceive from his dissec- 
tion of this vessel, the deep situation of the artery behind and beneath the sternum, and the 
number of important structures which surround it in every part. 
In order to apply a ligature to this vessel the patient is to be placed upon his back, with the 
shoulders raised and the head bent a little backward, so as to draw out the artery from behind 
the sternum into the neck. An incision two inches long is then made along the anterior border 
of the Sterno-mastoid muscle, terminating at the sternal end of the clavicle. From this point a 
second incision is carried about the same length along the upper border of the clavicle. The 
skin is then dissected back and the Platysma divided on a director: the sternal end of the 
Sterno-mastoid is now brought into view, and a director being passed beneath it and close to its 
under surface, so as to avoid any small vessels, the muscle is to be divided transversely through- 
out the greater part of its attachment. By pressing aside any loose cellular tissue or vessels that 
may now appear the Sterno-hyoid and Sterno-thyroid muscles will be exposed, and must be 
divided, a director being previously passed beneath them. The inferior thyroid veins may come 
into view, and must be carefully drawn either upward or downward by means of a blunt hook. On 
no account should these vessels be divided, as it would add much to the difficulty of the operation 
and endanger its ultimate success. After tearing through a strong fibro-cellular lamina the right 
carotid is brought into view, and, being traced downward, the arteria innominata is arrived at. 
The left vena innominata should now be depressed; the right vena innominata, the internal 
jugular vein, the pneumogastric nerve drawn to the right side; and a curved aneurism-needle 
may then be passed around the vessel close to its surface and in a direction from below upward 
and inward, care being taken to avoid the right pleural sac, the trachea, and cardiac nerves. 
The ligature should be applied to the artery as high as possible, in order to allow room between 
it and the aorta for the formation of the coagulum. The importance of avoiding the thyroid 
plexus of veins during the primary steps of the operation, and the pleural sac whilst including 
the vessel in the ligature, should be most carefully borne in mind, since secondary hemorrhage 
or pleurisy has been the cause of death in all the fatal cases hitherto recorded. 
Common Carotid Arteries. 
The Common Carotid. Arteries, although occupying a nearly similar position 
in the neck, differ in position, and consequently in their relations at their origin. 
The right carotid arises from the arteria innominata behind the right sterno-clavic- 
ular articulation; the left, from the highest part of the arch of the aorta. The left 
carotid is consequently longer and placed more deeply in the thorax. It will there- 
fore be more convenient to describe first the course and relations of that portion of 
the left carotid which intervenes between the arch of the aorta and the left sterno- 
clavicular articulation. (See Fig. 364.) 
The left carotid within the thorax ascends obliquely outward from the arch of 
the aorta to the root of the neck. In front it is separated from the first piece of 
the sternum by the Sterno-hyoid and Sterno-thyroid muscles, the left innominate 
vein, and the remains of the thymus gland; behind it lies on the trachea, oesopha- 
gus, and thoracic duct. Internally it is in relation with the arteria innominata; 
externally, with the left pneumogastric nerve and left subclavian artery. 
1 The operation was performed by Dr. Smyth of New Orleans. (See the New Sydenham Society's 
Biennial Retrospect for 1865-66, p. 346.) 510 
THE ARTERIES. 
Plan of the Relations of the Left Common Carotid, Thoracic Portion. 
In Front. 
Sternum. 
Sterno-hyoid and Sterno-thyroid muscles. 
Left innominate vein. 
Remains of thymus gland. 
Internally. 
Arteria innominata. 
'Left Common 
Carotid. 
Thoracic 
Portion. 
Externally. 
Left pneumogastric nerve. 
Left subclavian artery. 
Behind. 
Trachea. 
(Esophagus. 
Thoracic duct. 
In the neck the two common carotids resemble each other so closely that one 
description will apply to both. Each vessel passes obliquely upward from behind 
the sterno-clavicular articulation to a level with the upper border of the thyroid 
cartilage, where it divides into the external and internal carotid, these names being 
derived from the distribution of the arteries to the external parts of the head and 
face and to the internal parts of the cranium respectively. The course of the com- 
mon carotid is indicated by a line drawn from the sternal end of the clavicle below 
to a point midway between the angle of the jaw and the mastoid process above. 
[As it lies just under the anterior border of the Sterno-cleido-mastoid, this muscle 
forms an excellent guide to its position.] 
At the lower part of the neck the two common carotid arteries are separated 
from each other by a very small interval, which contains the trachea; but at the 
upper part, the thyroid body, the larynx, and pharynx project forward between the 
two vessels, and give the appearance of their being placed farther back in that sit- 
uation. The common carotid artery is contained in a sheath derived from the deep 
cervical fascia, which also encloses the internal jugular vein and pneumogastric 
nerve, the vein lying on the outer side of the artery and the nerve between the 
artery and vein, on a plane posterior to both. On opening the sheath these three 
structures are seen to be separated from one another, each being enclosed in a sep- 
arate fibrous investment. 
Relations.-At the lower part of the neck the common carotid artery is very 
deeply seated, being covered by the superficial fascia, Platysma, and deep fascia, the 
Sterno-mastoid, Sterno-hyoid, and Sterno-thyroicl muscles, and by the Omo-hyoid 
opposite the cricoid cartilage; but in the upper part of its course, near its termina- 
tion, it is more superficial, being covered merely by the integument, the superficial 
fascia, Platysma, deep fascia, and inner margin of the Sterno-mastoid, and is con- 
tained in a triangular space bounded behind by the Sterno-mastoid, above by the 
posterior belly of the Digastric, and below by the anterior belly of the Omo-hyoid. 
This part of the artery is crossed obliquely from within outward by the sterno- 
mastoid artery; it is crossed also by one, or sometimes two superior thyroid veins, 
which terminate in the internal jugular, and descending on its sheath in front is 
seen the descendens noni nerve, this filament being joined by one or two branches 
from the cervical nerves, which cross the vessel from without inward. Sometimes 
the descendens noni is contained within the sheath. The middle thyroid vein 
crosses the artery about its middle, and the anterior jugular vein below. Behind, 
the artery lies in front of the cervical portion of the spine, resting first on the 
Longus colli muscle, then on the Rectus capitis anticus major, from which it is sep- 
arated by the sympathetic nerve. The recurrent laryngeal nerve and inferior 
thyroid artery cross behind the vessel at its low'er part. Internally, it is in relation 
with the trachea and thyroid gland, the inferior thyroid artery and recurrent lar- 
yngeal nerve being interposed; higher up, with the larynx and pharynx. On its 
outer side are placed the internal jugular vein and pneumogastric nerve. COMMON CAROTID ARTERIES. 
511 
At the lower part of the neck the internal jugular vein on the right side diverges 
from the artery, but on the left side it approaches it, and often crosses its lower part. 
This is an important fact to bear in mind during the performance of any operation 
on the lower part of the left common carotid artery. 
Plan of the Relations of the Common Carotid Artery [Cervical Portion]. 
Integument and fascia. 
Platysma. 
Sterno-mastoid. 
Sterno-hyoid. 
Sterno-thyroid. 
In Front. 
Omo-hyoid. 
Descendens and Communicans noni nerves. 
Sterno-mastoid artery. 
Superior and middle thyroid veins. 
Anterior jugular vein. 
Internally. 
Trachea. 
Thyroid gland. 
Recurrent laryngeal nerve. 
Inferior thyroid artery. 
Larynx. 
Pharynx. 
Externally. 
Internal jugular vein. 
Pneumogastric nerve. 
Common 
Carotid. 
• Behind. 
Longus colli. Sympathetic nerve. 
Rectus capitis anticus major. Inferior thyroid artery. 
Recurrent laryngeal nerve. 
Peculiarities as to Origin.-The right common carotid may arise above or below its usual 
point, the upper border of the sterno-clavicular articulation. This variation occurs in one out of 
about eight cases and a half, and the origin is more frequently above than below the usual point; 
or the artery may arise as a separate branch from the arch of the aorta or in conjunction with 
the left carotid. The left common carotid varies more frequently in its origin than the right. 
In the majority of abnormal cases it arises with the innominate artery, or if the innominate artery 
is absent the two carotids arise usually by a single trunk. The left carotid has a tendency 
toward the right side of the arch of the aorta, being occasionally the first branch given off from 
the transverse portion. It rarely joins with the left subclavian, except in cases of transposition 
of the arch. 
Peculiarities as to Point of Division.-The most important peculiarities of this vessel 
in a surgical point of view relate to its place of division in the neck. In the majority of abnor- 
mal cases this occurs higher than usual, the artery dividing into two branches opposite the hyoid 
bone, or even higher; more rarely, it occurs below its usual place, opposite the middle of the 
larynx or the lower border of the cricoid cartilage ; and one case is related by Morgagni where 
the common carotid, only an inch and a half in length, divided at the root of the neck. Very 
rarely the common carotid ascends in the neck without any subdivision, the internal carotid being 
wanting; and in two cases the common carotid has been found to be absent, the external and 
internal carotids arising directly from the arch of the aorta. This peculiarity existed on both 
sides in one subject, on one side in the other. 
Occasional Branches.-The common carotid usually gives off no branch previous to its 
bifurcation; but it occasionally gives origin to the superior thyroid, or a laryngeal branch, the 
inferior thyroid, or, more rarely, the vertebral artery. 
Surgical Anatomy. [See the Triangles of the Neck, p. 525.]-The operation of tying the 
common carotid artery may be necessary in a case of wound of that vessel or its branches, in 
aneurism, or in a case of pulsating tumor of the orbit or skull. If the wound involves the trunk 
of the common carotid, it will be necessary to tie the artery above and below the wounded part. 
But in cases of aneurism, or where one of the branches of the common carotid is wounded in an 
inaccessible situation, it may be judged necessary to tie the trunk. In such cases the whole of 
the artery is accessible, and any part may be tied, except close to either end. When the case is 
such as to allow of a choice being made, the lower part of the carotid should never be selected as 
the spot upon which to place a ligature, for not only is the artery in this situation placed very 
deeply in the neck, but it is covered by three layers of muscles, and on the left side the jugular 
vein, in the great majority of cases, passes obliquely in front of it. Neither should the upper end 
be selected, for here the superior thyroid vein and its tributaries would give rise to very consid- 
erable difficulty in the application of a ligature. The point most favorable for the operation is 
that part of the vessel which bisects the angle formed by the anterior edge of the Sterno-mastoid 
with the Omo-hyoid muscle, at the level of the cricoid cartilage. It occasionally happens that 
the carotid artery bifurcates below its usual position: if the artery be exposed at its point of 
bifurcation, both divisions of the vessel should be tied near their origin, in preference to tying 
the trunk of' the artery near its termination; and if, in consequence of the entire absence of the 
common carotid or from its early division, two arteries, the external and internal carotids, are 
met with, the ligature should be placed on that vessel which is found on compression to be con- 
nected with the disease. 512 
THE ARTERIES. 
In this operation the direction of the vessel and the inner margin of the Sterno-mastoid are 
the chief guides to its performance. The patient should be placed on his back with the head 
thrown back: an incision is to be made, three inches long, along the anterior border of the 
Sterno-mastoid, so that the centre corresponds to the level of the cricoid cartilage; after dividing 
the integument, superficial fascia, and Platysma, the deep fascia must be cut through on a direc- 
tor, so as to avoid wounding numerous small veins that are usually found beneath. The head 
may now be brought forward so as to relax the parts somewhat, and the margins of the wound 
held asunder by retractors. The descendens noni nerve is now exposed, and must be avoided, 
and the sheath of the vessel, having been raised by forceps, is to be opened to a small extent over 
the artery at its inner side. The internal jugular vein may present itself alternately distended 
and relaxed ; this should be compressed both above and below, and drawn outward, in order to 
facilitate the operation. The aneurism-needle is passed from the outside, care being taken to 
keep the needle in close contact with the artery, and thus avoid the risk of injuring the jugular 
vein or including the vagus nerve. Before the ligature is tied it should be ascertained that noth- 
ing but the artery is included in it. 
Ligature of the Common Carotid, at the Lower Part of the Neck.-This opera- 
tion is sometimes required in cases of aneurism of the upper part of the carotid, especially if the 
sac is of large size. It is best performed by dividing the sternal origin of the Sterno-mastoid 
muscle, but may be done in some cases, if the aneurism is not of very large size, by an incision 
along the anterior border of the Sterno-mastoid, extending down to the sterno-clavicular articula- 
tion, and by then retracting the muscle. The easiest and best plan, however, is to make an 
incision two or three inches long down the lower part of the anterior border of the Sterno-mastoid 
muscle to the sterno-clavicular joint, and a second incision, starting from the termination of the 
first, along the upper border of the clavicle for about two inches. This incision is made through 
the superficial and deep fascia, and the sternal origin of the muscle exposed. This is to be divided 
on a director and turned up with the superficial structures as a triangular flap. Some loose con- 
nective tissue is now to be divided or torn through, and the outer border of the Sterno-hyoid 
muscle exposed. In doing this care must be taken not to wound the anterior jugular vein, which 
crosses the muscle to reach the external jugular or subclavian vein. The Sterno-hyoid, and with 
it the Sterno thyroid, are now to be drawn inward by means of a retractor, and the sheath of the 
vessel is exposed. This must be opened with great care on its inner or tracheal side, so as to 
avoid the internal jugular vein. This is especially necessary on the left side, where the artery is 
commonly overlapped by the vein. On the right side there is usually an interval between the 
artery and the vein, and not the same risk of wounding the latter. 
Collateral Circulation.-After ligature of the common carotid the collateral circulation 
can be perfectly established by the free communication which exists between the carotid arteries 
of opposite sides, both without and within the cranium, and by enlargement of the branches 
of the subclavian artery on the side corresponding to that on which the vessel has been tied, the 
chief communication outside the skull taking place between the superior and inferior thyroid 
arteries and the profunda cervicis and arteria princeps cervicis of the occipital, the vertebral 
taking the place of the internal carotid within the cranium. 
Sir A. Cooper had an opportunity of dissecting, thirteen years after the operation, the case in 
which he first successfully tied the common carotid-the second case in which he performed the 
operation (Guy's Hospital Reports, i. 56). The injection, however, does not seem to have been 
a successful one. It showed merely that the arteries at the base of the brain (circle of Willis) 
were much enlarged on the side of the tied artery, and that the anastomosis between the branches 
of the external carotid on the affected side and those of the same artery on the sound side was 
free, so that the external carotid was pervious throughout. 
External Carotid Artery. 
The External Carotid Artery (Fig. 366) commences opposite the upper border 
of the thyroid cartilage, and, taking a slightly curved course, ascends upward and 
forward, and then inclines backward, to the space between the neck of the condyle 
of the lower jaw and the external meatus, where it divides into the temporal and 
internal maxillary arteries. It rapidly diminishes in size in its course up the neck, 
owing to the number and large size of the branches given off from it. In the child 
it is somewhat smaller than the internal carotid, but in the adult the two vessels are 
of nearly equal size. At its commencement this artery is more superficial and placed 
nearer the middle line than the internal carotid, and is contained in the triangular 
space bounded by the Sterno-mastoid behind, the Omo-hyoid below, and the poste- 
rior belly of the Digastric and Stylo-hyoid above; it is covered by the skin, Pla- 
tysma, deep fascia, and anterior margin of the Sterno-mastoid, crossed by the hypo- 
glossal nerve and by the lingual and facial veins; it is afterward crossed by the 
Digastric and Stylo-hyoid muscles, and higher up passes deeply into the substance 
of the parotid gland, where it lies beneath the facial nerve and the junction of the 
temporal and internal maxillary veins. EXTERNAL CAROTID ARTERY. 
513 
Internally is the hyoid bone, the wall of the pharynx, the superior laryngeal 
nerve, and the ramus of the jaw, from which it is separated by a portion of the 
parotid gland. Behind it, near its origin, is the superior laryngeal nerve, and 
Fig. 366. 
Fig. 367. 
"HYPOGLOSSAL 
NERVE 
- Crico- Thyroid Ay. 
Plan of the Branches of the 
External Carotid. 
Surgical Anatomy of the Arteries of the Neck, right side. [The hypoglossal nerve is not rightly placed in this 
drawing. It forms the upper side of a triangle the two lower sides of which are the two bellies of the Digas- 
tric. The lingual artery would then run under the Hyo-glossus muscle, below the hypoglossal nerve.] 
higher up it is separated from the internal carotid by the Stylo-glossus and Stylo- 
pharyngeus muscles, the glosso-pharyngeal nerve, and part of the parotid gland. 514 
THE ARTERIES. 
Plan of the Relations of the External Carotid. 
In Front. 
Integument, superficial fascia. 
Platysma and deep fascia. 
Hypoglossal nerve. 
Lingual and facial veins. 
Digastric and Stylo-hyoid muscles. 
Parotid gland, with facial nerve and 
temporo-maxillary vein in its sub- 
stance. 
Behind. 
Superior laryngeal nerve. 
Stylo-glossus. 
Stylo-pharyngeus. 
Glosso-pharyngeal nerve. 
Parotid gland. 
External 
Carotid. 
Internally. 
Hyoid bone. 
Pharynx. 
Superior laryngeal nerve. 
Parotid gland. 
Ramus of jaw. 
Surgical Anatomy.-The application of a ligature to the external carotid may be required 
in cases of wounds of this vessel or of its branches (when these cannot be tied) and in some cases 
of pulsating tumor of the scalp or face ; the operation, however, is very rarely performed, ligature 
of the common carotid being preferable on account of the number of branches given off from the 
external. To tie this vessel near its origin, below the point where it is crossed by the Digastric, 
an incision about three inches in length should be made along the margin of the Sterno-mastoid 
from the angle of the jaw to the cricoid cartilage. To tie the vessel above the Digastric, between 
it and the parotid gland, an incision should be made from the lobe of the ear to the great cornu 
of the os hyoides, dividing successively the skin, Platysma, and fascia. By separating the pos- 
terior belly of the Digastric and Stylo-hyoid muscles, which are seen at the lower part of the 
wound, from the parotid gland, the vessel will be exposed and a ligature may be applied to it. 
The circulation is at once re-established by the free communication between most of the large 
branches of the artery (facial, lingual, superior thyroid, occipital) and the corresponding arteries 
of the opposite side, and by the free anastomosis of the facial with branches from the internal 
carotid, of the occipital with branches of the subclavian, etc. 
Branches.-The external carotid artery gives off eight branches, which, for 
convenience of description, may be divided into four sets. (See Fig. 367, Plan of 
the Branches.) 
Anterior. 
Superior Thyroid. 
Lingual. 
Facial. 
Posterior. 
Occipital. 
Posterior Auricular. 
Ascending. 
Ascending Pha- 
ryngeal. 
Terminal. 
Temporal. 
Internal Maxillary. 
The student is here reminded that many variations are met with in the number, 
origin, and course of these branches in different subjects, but the above arrange- 
ment is that which found in the great majority of cases. 
The Superior Thyroid Artery (Fig. 366, and Fig. 372, p. 529) is the first branch 
given oft' from the external carotid, being derived from that vessel just below the great 
cornu of the hyoid bone. At its commencement it is quite superficial, being covered 
by the integument, fascia, and Platysma, and is contained in the triangular space 
bounded by the Sterno-mastoid, Digastric, and Omo-hyoid muscles. After running 
upward and inward for a short distance, it curves downward and forward in an 
arched and tortuous manner to the upper part of the thyroid gland, passing beneath 
the Omo-hyoid, Sterno-hyoid, and Sterno-thyroid muscles, and distributes numerous 
branches to the anterior surface of the gland, anastomosing with its fellow of the 
opposite side and with the inferior thyroid arteries. Besides the arteries distributed 
.o the muscles by which it is covered and the substance of the gland, the branches 
of the superior thyroid are the following: 
Hyoid. 
Superficial Descending Branch (Sterno-mastoid). 
Superior Laryngeal. 
Crico-thyroid. 
The hyoid is a small branch which runs along the lower border of the os 
hyoides beneath the Thyro-hyoid muscle; after supplying the muscles connected 
to that bone it forms an arch by anastomosing with the vessels of the opposite 
side. EXTERNAL CAROTID ARTERY. 
515 
The superficial descending branch runs downward and outward across the 
sheath of the common carotid artery, and supplies the Sterno-mastoid and neigh- 
boring muscles and integument. It is of importance that the situation of this 
vessel be remembered in the operation for tying the common carotid artery. 
There is often a distinct branch from the external carotid distributed to the 
Sterno-mastoid muscle. 
The superior laryngeal, larger than either of the preceding, accompanies the 
superior laryngeal nerve beneath the Thyro-hyoid muscle; it pierces the thyro- 
hyoid membrane, and supplies the muscles, mucous membrane, and glands of the 
larynx and epiglottis, anastomosing with the branch from the opposite side. 
The crico-thyroid is a small branch which runs transversely across the crico- 
thyroid membrane, communicating with the artery of the opposite side. The posi- 
tion of this vessel should be remembered, as it may prove the source of troublesome 
hemorrhage during the operation of laryngotomy. 
Surgical Anatomy.-The superior thyroid or some of its branches are often divided in 
cases of cut throat, giving rise to considerable hemorrhage. In such cases the artery should be 
secured, the wound being enlarged for that purpose if necessary. The operation may be easily 
performed, the position of the artery being very superficial and the only structures of importance 
covering it being a few small veins. The operation of tying the superior thyroid artery in 
bronchocele has been performed in numerous instances with partial or temporary success. 
When, however, the collateral circulation between this vessel and the artery of the opposite 
side and the inferior thyroid is completely re-established, the tumor usually regains its former 
size. 
The Lingual Artery (Fig. 372 p. 529) arises from the external carotid between 
the superior thyroid and facial; it runs obliquely upward and inward to the great 
cornu of the hyoid bone, then passes horizontally forward parallel with the great 
cornu, and, ascending perpendicularly to the under surface of the tongue, turns for- 
ward on its under surface as far as the tip of that organ, under the name of the ranine 
artery. 
Relations.-Its first or oblique portion is superficial, being contained in the 
triangular space already described, resting upon the middle constrictor of the 
pharynx, and covered by the Platysma and fascia of the neck. Its second or 
horizontal portion also lies upon the Middle constrictor, being covered at first by 
the tendon of the Digastric and the Stylo-hyoid muscle, and afterward by the 
Hyo-glossus, the latter muscle separating it from the hypoglossal nerve. [This 
portion lies in a triangle, the two lower sides of which are the two bellies of the 
Digastric, and the upper side is the hypoglossal nerve (Fig. 366 is incorrect in this 
portion). The artery lies below the hypoglossal nerve, above the Digastric, and 
beneath the Hyo-glossus.] Its third or ascending portion lies between the Hyo- 
glossus and Genio-hyo-glossus muscles. The fourth or terminal part under the 
name of the ranine runs along the under surface of the tongue to its tip: it is 
very superficial, being covered only by the mucous membrane, and rests on the 
Lingualis on the outer side of the Genio-hyo-glossus. The hypoglossal nerve 
crosses the lingual artery, and then becomes separated from it, in the second part 
of its course, by the Hyo-glossus muscle. 
The branches of the lingual artery are the 
Hyoid. 
Dorsalis linguae. 
Sublingual. 
Ranine. 
The hyoid branch runs along the upper border of the hyoid bone, supplying the 
muscles attached to it and anastomosing with its fellow of the opposite side. 
The dorsalis linguae (Fig. 372) arises from the lingual artery beneath the Hyo- 
glossus muscle (which in the figure has been partly cut away to show the vessel); 
ascending to the dorsum of the tongue, it supplies the mucous membrane, the tonsil, 
soft palate, the epiglottis, anastomosing with its fellow from the opposite side. 
The sublingual, which may be described as a branch of bifurcation of the lingual 
artery, arises at the anterior margin of the Hyo-glossus muscle, and, running for- 516 
THE ARTERIES. 
ward and outward on the Genio-hyo-glossus to the sublingual gland, supplies its 
substance, giving branches to the Mylo-hyoid and neighboring muscles, the mucous 
membrane of the mouth and gums. One branch continues behind the alveolar 
process of the lower jaw in the substance of the gum to anastomose with a similar 
artery from the other side. 
The ranine may be regarded as the other branch of bifurcation, or, as is more 
usual, as the continuation of the lingual artery; it runs along the under surface of 
the tongue, resting on the Lingualis and covered by the mucous membrane of the 
mouth ; it lies on the outer side of the Genio-hyo-glossus, accompanied by the gus- 
tatory nerve. On arriving at the tip of the tongue it has been said to anastomose 
with the artery of the opposite side, but this is denied by Hyrtl. These vessels in 
the mouth are placed one on each side of the fraenum. 
Surgical Anatomy.-The lingual artery may be divided near its origin in cases of cut 
throat, a complication that not unfrequently happens in this class of wounds, or severe hemor- 
rhage, which cannot be restrained by ordinary means, may ensue from a wound or deep ulcer of 
the tongue. In the former case the primary wound may be enlarged if necessary, and the bleed- 
ing vessel secured. In the latter case it has been suggested that the lingual artery should be tied 
near its origin. Ligature of the lingual artery is also occasionally practised as a palliative meas- 
ure in cases of cancer of the tongue, in order to check the progress of the disease by starving the 
growth. The operation is a difficult one, on account of the depth of the artery, the number of 
important parts by which it is surrounded, the loose and yielding nature of the parts upon which 
it is supported, and its occasional irregularity of origin. An incision is to be made in a curved 
direction from a finger's breadth external to the symphysis of the jaw downward to the cornu of 
the hyoid bone, and then upward to near the angle of the jaw. Care must be taken not to carry 
this incision too far backward, for fear of endangering the facial vein. In the first incision the 
skin, superficial fascia, and Platysma will be divided and the deep fascia exposed. This is then 
to be incised and the submaxillary gland exposed and pulled upward by retractors. A triangu- 
lar space is now exposed, bounded internally by the posterior border of the Mylo-hyoid muscle, 
below and externally by the tendon of the Digastric, and above by the hypoglossal nerve. The 
floor of the space is formed by the Hyo-glossus muscle, beneath which the artery lies. The fibres 
of this muscle are now to be cut through horizontally and the vessel exposed, care being taken 
while near the vessel not to open the pharynx. [There need be no trouble in finding and ligat- 
ing this artery. After the submaxillary gland is raised up, find the hyoid bone and the triangle 
formed by the Digastric tendons and the hypoglossal nerve, and if the Hyo-glossus muscle be 
then divided in this triangle between the bone and the nerve, the artery will readily be found 
under it.] 
Troublesome hemorrhage may occur in the division of the frsenum in children if the ranine 
artery, which lies on each side of it, is wounded. The student should remember that the opera- 
tion is always to be performed with a pair of blunt-pointed scissors, and the mucous membrane 
only is to be divided by a very superficial cut, which cannot endanger any vessel. The scissors 
also should be directed away from the tongue. Any further liberation of the tongue which may 
be necessary can be effected by tearing. 
The Facial Artery (Fig. 368) arises a little above the lingual, and ascends 
obliquely forward and upward, beneath the body of the lower jaw, to the submax- 
illary gland, in which it lies imbedded in a groove on its posterior and upper bor- 
der ; this may be called the cervical part of the artery. It then curves upward 
over the body of the jaw at the anterior inferior angle of the Masseter muscle, 
ascends forward and upward across the cheek to the angle of the mouth, passes up 
along the side of the nose, and terminates at the inner canthus of the eye, under 
the name of the angular artery. This vessel, both in the neck and on the face, is 
remarkably tortuous-in the former situation, to accommodate itself to the move- 
ments of the pharynx in deglutition; and in the latter, to the movements of the 
jaw and the lips and cheeks. 
Relations.- Tn the neck its origin is superficial, being covered by the integu- 
ment, Platysma, and fascia; it then passes beneath the Digastric and Stylo-hyoid 
muscles and the submaxillary gland. On the face, where it passes over the body 
of the lower jaw, it is comparatively superficial, lying immediately beneath the 
Platysma. In this situation its pulsation may be distinctly felt, and compression 
of the vessel effectually made against the bone. In its course over the face it is 
covered by the integument, the fat of the cheek, and, near the angle of the mouth, 
by the Platysma, Risorius, and Zygomatic muscles. It rests on the Buccinator, the 
Levator anguli oris, and the Levator labii superioris (sometimes piercing or else EXTERNAL CAROTID ARTERY. 
517 
passing under this last muscle). It is accompanied by the facial vein throughout 
its entire course; the vein is not tortuous like the artery, and on the face is sepa- 
rated from that vessel by a considerable interval, lying to its outer side. The 
Fig. 368. 
Angular 
Nasi 
Jt* Septi Nati 
r-Superior 
/ Coronary 
J-Liferior Coro nary 
'Inferior Labial 
The Arteries of the Face and Scalp.1 
branches of the facial nerve cross the artery, and the infraorbital nerve lies 
beneath it. 
The branches of this vessel may be divided into two sets-those given off below 
the jaw (cervical), and those on the face (facial): 
Cervical Branches. 
Inferior or Ascending Palatine. 
Tonsillar. 
Submaxillary. 
Submental. 
Muscular. 
Facial Branches. 
Muscular. 
Inferior Labial. 
Inferior Coronary. 
Superior Coronary. 
Lateralis nasi. 
Angular. 
The inferior or ascending1 palatine (Fig. 372, p. 529) passes up between the Stylo- 
glossus and Stylo-pharyngeus to the outer side of the pharynx. After supplying 
these muscles, the tonsil, and Eustachian tube, it divides, near the Levator palati, 
into two branches: one follows the course of the Levator palati, and, winding over 
1 The muscular tissue of the lips must be supposed to have been cut away in order to show the 
course of the coronary arteries. 518 
THE ARTERIES. 
the upper border of the Superior constrictor, supplies the soft palate and the pala- 
tine glands; the other pierces the Superior constrictor and supplies the tonsil, anas- 
tomosing with the tonsillar artery. These vessels inosculate with the posterior 
palatine branch of the internal maxillary artery. 
The tonsillar branch (Fig. 372, p. 529) passes between the Internal pterygoid 
and Stylo-glossus, and ascends along the side of the pharynx, perforating the Supe- 
rior constrictor, to ramify in the substance of the tonsil and root of the tongue. 
The submaxillary consist of three or four large branches, which supply the 
submaxillary gland, some being prolonged to the neighboring muscles, lymphatic 
glands, and integument. 
The submental, the largest of the cervical branches, is given off from the facial 
artery just as that vessel quits the submaxillary gland; it runs forward upon the 
Mylo-hyoid muscle just below the body of the jaw and beneath the Digastric; 
after supplying the muscles attached to the jaw, and anastomosing with the sub- 
lingual artery by branches which perforate the Mylo-hyoid muscle, it arrives at the 
symphysis of the chin, where it turns over the border of the jaw and divides into 
a superficial and deep branch; the former passes between the integument and 
Depressor labii inferioris, supplies both, and anastomoses with the inferior labial. 
The deep branch passes between the latter muscle and the bone, supplies the- lip, 
and anastomoses with the inferior labial and mental arteries. 
The muscular branches are distributed to the Internal pterygoid and Stylo- 
hyoid in the neck, and to the Masseter and Buccinator on the face. 
The inferior labial passes beneath the Depressor anguli oris to supply the mus- 
cles and integument of the lower lip, anastomosing with the inferior coronary and 
submental branches of the facial and with the mental branch of the inferior dental 
artery. 
The inferior coronary is derived from the facial artery near the angle of the 
mouth; it passes upward and inward beneath the Depressor anguli oris, and, pene- 
trating the Orbicularis muscle, runs in a tortuous course along the edge of the 
lower lip between this muscle and the mucous membrane, inosculating with the 
artery of the opposite side. This artery supplies the labial glands, the mucous 
membrane, and muscles of the lower lip, and anastomoses with the inferior labial 
and mental branch of the inferior dental artery. 
The superior coronary is larger and more tortuous in its course than the pre- 
ceding. It follows the same course along the edge of the upper lip, lying between 
the mucous membrane and the Orbicularis, and anastomoses with the artery of the 
opposite side. It supplies the textures of the upper lip, and gives off in its course 
two or three vessels which ascend to the nose. One, named the artery of the septum, 
ramifies on the septum of the nares as far as the point of the nose; another sup- 
plies the ala of the nose. 
The lateralis nasi is derived from the facial as that vessel is ascending along 
the side of the nose; it supplies the ala and dorsum of the nose, anastomosing with 
its fellow, the nasal branch of the ophthalmic, the artery of the septum, and the 
infraorbital. 
The angular artery is the termination of the trunk of the facial; it ascends to 
the inner angle of the orbit, imbedded in the fibres of the Levator labii superioris 
alseque nasi, and accompanied by a large vein, the angular; it distributes some 
branches on the cheek which anastomose with the infraorbital, and, after supplying 
the lachrymal sac and Orbicularis muscle, terminates by anastomosing with the nasal 
branch of the ophthalmic artery. 
The anastomoses of the facial artery are very numerous, not only with the vessel 
of the opposite side, but with other vessels from different sources-viz. with the sub- 
lingual branch of the lingual, with the mental branch of the inferior dental as it 
emerges from the mental foramen, with the ascending pharyngeal and posterior pala- 
tine, and with the ophthalmic, a branch of the internal carotid; it also inosculates 
with the transverse facial and with the infraorbital. EXTERNAL CAROTID ARTERY. 
519 
Peculiarities.-The facial artery not unfrequently arises by a common trunk with the 
lingual. This vessel also is subject to some variations in its size and in the extent to which it 
supplies the face. It occasionally terminates as the submental, and not unfrequently supplies 
the face only as high as the angle of the mouth or nose. The deficiency is then supplied by 
enlargement of one of the neighboring arteries. 
Surgical Anatomy.-The passage of the facial artery over the body of the jaw would 
appear to afford a favorable position for the application of pressure in cases of hemorrhage from 
the lips, the result either of an accidental wound or from an operation; but its application is 
useless, except for a very short time, on account of the free communication of this vessel with its 
fellow and with numerous branches from different sources. In a wound involving the lip it is 
better to seize the part between the fingers and evert it, when the bleeding vessel may be at once 
secured with artery-forceps. In order to prevent hemorrhage in cases of excision or in the 
removal of diseased growths from the part, the lip should be compressed on each side between 
the finger and thumb whilst the surgeon excises the diseased part. In order to stop hemorrhage 
where the lip has been divided in an operation, it is necessary, in uniting the edges of the wound, 
to pass the sutures through the cut edges almost as deep as its mucous surface [since the coro- 
nary arteries run next the mucous membrane, where the moistened finger can feel them] : by 
these means not only are the cut surfaces more neatly and securely adapted to each other, but 
the possibility of hemorrhage is prevented by including in the suture the divided artery. If the 
suture is, on the contrary, passed through merely the cutaneous portion of the wound, hemor- 
rhage occurs into the cavity of the mouth. The student should, lastly, observe the relation of 
the angular artery to the lachrymal sac, and it will be seen that as the vessel passes up along the 
inner margin of the orbit it ascends on its nasal side. In operating for fistula lachrymalis the 
sac should always be opened on its outer side, in order that this vessel may be avoided. 
The Occipital Artery (Fig. 368) arises from the posterior part of the external 
carotid opposite the facial, near the lower margin of the Digastric muscle. At its 
origin it is covered by the posterior belly of the Digastric and Stylo-hyoid muscles 
and part of the parotid gland, the hypoglossal nerve winding around it from behind 
forward; higher up it passes across the internal carotid artery, the internal jugular 
vein, and the pneumogastric and spinal accessory nerves; it then ascends to the 
interval between the transverse process of the atlas and the mastoid process of the 
temporal bone, and passes horizontally backward, grooving the surface of the latter 
bone, being covered by the Sterno-mastoid, Splenius, Trachelo-mastoid, and Digas- 
tric muscles, and resting upon the Superior oblique and Complexus muscles ; it then 
changes its course and passes vertically upward, pierces the cranial attachment of 
the Trapezius, and ascends in a tortuous course over the occiput as high as the ver- 
tex, where it divides into numerous branches. It is accompanied in the latter part 
of its course by the great occipital and a cutaneous filament from the suboccipital 
nerve. 
The branches given off from this vessel are the 
Muscular. 
Sterno-mastoid. 
Auricular. 
Meningeal. 
Arteria princeps cervicis. 
The muscular branches supply the Digastric, Stylo-hyoid, Splenius, and 
Trachelo-mastoid muscles. 
The sterno-mastoid is a large and constant branch, generally arising from the 
artery close to its commencement. It first ascends upward and backward, and then 
turns downward over the hypoglossal nerve, and enters the substance of the muscle, 
frequently in company with the spinal accessory nerve. 
The auricular branch supplies the back part of the concha. It frequently 
gives off a branch which enters the skull through the mastoid foramen and supplies 
the dura mater. 
The meningeal branch ascends with the internal jugular vein, and enters the 
skull through the foramen lacerum posterius, to supply the dura mater in the pos- 
terior fossa. 
The arteria princeps cervicis (Fig. 372, p. 529) is a large branch which descends 
along the back part of the neck and divides into a superficial and deep branch. The 
former runs beneath the Splenius, giving off branches which perforate that muscle to 
supply the Trapezius, anastomosing with the superficial cervical artery: the latter 
passes beneath the Complexus, between it and the Semispinalis colli, and anasto- 520 
THE ARTERIES. 
moses with the vertebral and deep cervical branch of the superior intercostal. The 
anastomosis between these vessels serves mainly to establish the collateral circulation 
after ligature of the carotid or subclavian artery. 
The cranial branches of the occipital artery are distributed upon the occiput; 
they are very tortuous, and lie between the integument and Occipito-frontalis, anas- 
tomosing with the artery of the opposite side, the posterior auricular, and temporal 
arteries. They supply the back part of the Occipito-frontalis muscle, the integu- 
ment, and pericranium. 
The Posterior Auricular Artery (Fig. 368) is a small vessel which arises from 
the external carotid above the Digastric and Stylo-hyoid muscles, opposite the apex 
of the styloid process. It ascends, under cover of the parotid gland, to the groove 
between the cartilage of the ear and the mastoid process, immediately above which 
it divides into two branches-an interior, passing forward to supply the back of the 
auricle and anastomose with the posterior division of the temporal; and a posterior, 
to the scalp above and behind the ear, communicating with the occipital. Just before 
arriving at the mastoid process this artery is crossed by the portio dura, and has 
beneath it the spinal accessory nerve. 
Besides several small branches to the Digastric, Stylo-hyoid, and Sterno-mastoid 
muscles and to the parotid gland, this vessel gives off two branches: 
Stylo-mastoid. 
Auricular. 
The stylo-mastoid branch enters the stylo-mastoid foramen and supplies the 
tympanum, mastoid cells, and semicircular canals. In the young subject a branch 
from this vessel forms, with the tympanic branch from the internal maxillary, a vas- 
cular circle which surrounds the auditory meatus, and from which delicate vessels 
ramify on the membrana tympani. It anastomoses with the petrosal branch of the 
middle meningeal artery by a twig which enters the hiatus Fallopii. 
The auricular branch is distributed to the back part of the cartilage of the 
ear, upon which it ramifies minutely, some branches curving round the margin of 
the fibro-cartilage, others perforating it to supply its anterior surface. It anastomoses 
with the anterior auricular branches of the temporal. 
The Ascending- Pharyngeal Artery (Fig. 372), the smallest branch of the 
external carotid, is a long slender vessel deeply seated in the neck, beneath the 
other branches of the external carotid and the Stylo-pharyngeus muscle. It arises 
from the back part of the external carotid, near the commencement of that vessel, 
and ascends vertically, between the internal carotid and the side of the pharynx, 
to the under surface of the base of the skull, lying on the Rectus capitis anticus 
major. Its branches may be subdivided into three sets: 1, Those directed outward 
to supply muscles and nerves ; 2, those directed inward to the pharynx ; 3, menin- 
geal branches. 
The external branches are numerous small vessels which supply the Recti cap- 
itis antici and Longus colli muscles, the sympathetic, hypoglossal, and pneumogas- 
tric nerves, and the lymphatic glands of the neck, anastomosing with the ascending 
cervical artery. 
The pharyngeal branches are three or four in number. Two of these descend 
to supply the Middle and Inferior constrictors and the Stylo-pharyngeus, ramifying 
in their substance and in the mucous membrane lining them. The largest of the 
pharyngeal branches passes inward, running upon the Superior constrictor, and 
sends ramifications to the soft palate and tonsil, which take the place of the 
ascending palatine branch of the facial artery when that vessel is of small size. 
A twig from this branch passes up the Eustachian tube to supply the tympanum. 
The meningeal branches consist of several small vessels which pass through 
foramina in the base of the skull to supply the dura mater. One, the posterior 
meningeal, enters the cranium through the foramen lacerum posterius with the 
internal jugular vein. A second passes through the foramen lacerum medium, and 
occasionally a third through the anterior condyloid foramen. They are all distrib- 
uted to the dura mater. EXTERNAL CAROTID ARTERY. 
521 
The Temporal Artery (Fig. 368), the smaller of the two terminal branches 
of the external carotid, appears, from its direction, to be the continuation of that 
vessel. It commences in the substance of the parotid gland, in the interspace 
between the neck of the condyle of the lowei' jaw and the external meatus, crosses 
over the root of the zygoma immediately beneath the integument, and divides 
about two inches above the zygomatic arch into two branches, an anterior and a 
posterior. 
The anterior temporal inclines forward over the forehead, supplying the mus- 
cles, integument, and pericranium in this region, and anastomoses with the supra- 
orbital and frontal arteries. [This can easily be felt, and may be used to count 
the pulse in sleeping children and in etherizing.] 
The posterior temporal, larger than the anterior, curves upward and back- 
ward along the side of the head, lying above the temporal fascia, and inosculates 
with its fellow of the opposite side and with the posterior auricular and occipital 
arteries. 
The temporal artery, as it crosses the zygoma, is covered by the Attrahens 
aurem muscle and by a dense fascia given off from the parotid gland; it is also 
usually crossed by one or two veins and accompanied by branches of the facial and 
auriculo-temporal nerves. Besides some twigs to the parotid gland, the articulation 
of the jaw, and the Masseter muscle, its branches are the 
Transverse Facial. 
Anterior Auricular. 
Middle Temporal. 
The transverse facial is given off from the temporal before that vessel quits 
the parotid gland; running forward through its substance, it passes transversely 
across the face, between Stenson's duct and the lower border of the zygoma, and 
divides on the side of the face into numerous branches, which supply the parotid 
gland, the Masseter muscle, and the integument, anastomosing with the facial, mas- 
seteric, and infraorbital arteries. This vessel rests on the Masseter, and is accom- 
panied by one or two branches of the facial nerve. It is sometimes a branch of 
the external carotid. 
The middle temporal artery arises immediately above the zygomatic arch, 
and, perforating the temporal fascia, supplies the Temporal muscle, anastomosing 
with the deep temporal branches of the internal maxillary. It occasionally gives 
off an orbital branch which runs along the upper border of the zygoma, between 
the two layers of the temporal fascia, to the outer angle of the orbit. This branch 
supplies the Orbicularis palpebrarum, and anastomoses with the lachrymal and pal- 
pebral branches of the ophthalmic artery. 
The anterior auricular branches are distributed to the anterior portion of the 
pinna, the lobule, and part of the external meatus, anastomosing with branches of 
the posterior auricular. 
Surgical Anatomy.-It occasionally happens that the surgeon is called upon to perform 
the operation of arteriotomy upon this vessel in cases of inflammation of the eye or brain. Under 
these circumstances the anterior branch is the one usually selected. If the student will consider 
the relations of the trunk of this vessel, as it crosses the zygomatic arch, with the surrounding 
structures, he will observe that it is covered by a thick and dense fascia, crossed by one or two 
veins, and accompanied by branches of the facial and auriculo-temporal nerves. Bleeding should 
not be performed in this situation, as much difficulty may arise from the dense fascia over the 
vessel preventing a free flow of blood, and considerable pressure is requisite afterward to repress 
the hemorrhage. Again, a varicose aneurism may be formed by the accidental opening of one 
of the veins in front of the artery, or severe neuralgic pain may arise from the operation, impli- 
cating one of the nervous filaments in the neighborhood. 
The anterior branch, on the contrary, is subcutaneous, is a large vessel, and is as readily com- 
pressed as any other portion of the artery ; it should consequently always be selected for -the 
operation. 
The Internal Maxillary (Fig. 369), the larger of the two terminal branches of 
the external carotid, passes inward, at right angles from that vessel, to the inner 
side of the neck of the condyle of the lower jaw, to supply the deep structures of 522 
THE ARTERIES. 
the face. At its origin it is imbedded in the substance of the parotid gland, being 
on a level with the lower extremity of the lobe of the ear. 
In the first part of its course (maxillary portion) the artery passes horizontally 
forward and inward between the ramus of the jaw and the internal lateral ligament. 
The artery here lies parallel with the auriculo-temporal nerve; it crosses the inferior 
dental nerve and lies beneath the narrow portion of the External pterygoid muscle. 
Fig. 309. 
Incisor 
Fig. 370. 
Plan of the Branches. 
\Pteryyc -P'alatint 
J Vidian 
iDCWndiny Palatine 
no Palatine 
ttltUle Miniiigeal ~- 
Mcniiujwn Parva- 
TyrnfiaJiic- 
I'jyferlc'r Dental- 
Deep. •Temjwral' 
In the second part of its course (pterygoid portion) it runs obliquely forward 
and upward upon the outer surface of the External pterygoid muscle, being cov- 
ered by the ramus of the lower jaw and lower part of the Temporal muscle. 
In the third part of its course (spheno-maxillary portion) it approaches the supe- 
rior maxillary bone, and enters the spheno-maxillary fossa in the interval between 
the processes of origin of the External pterygoid, where it lies in relation with 
Meckel's ganglion and gives off its terminal branches. 
Peculiarities.-Occasionally this artery passes between the two Pterygoid muscles. The 
vessel in this case passes forward to the interval between the processes of origin of the External 
pterygoid, in order to reach the superior maxillary bone. Sometimes the vessel escapes from 
beneath the External pterygoid by perforating the middle of that muscle. 
The branches of this vessel may be divided into three groups, corresponding 
with its three divisions. 
The Internal Maxillary Artery and its Branches. EXTERNAL CAROTID ARTERY. 
523 
Branches from the Maxillary Portion (Fig. 370). 
Tympanic (anterior). 
Midclle Meningeal. 
Small Meningeal. 
Inferior Dental. 
The tympanic branch passes upward behind the articulation of the lower jaw, 
enters the tympanum through the fissure of Glaser, and ramifies upon the mem- 
brana tympani, forming a vascular circle around the membrane with the stylo- 
mastoid artery and anastomosing with the Vidian and tympanic branch from the 
internal carotid. It gives off an auricular branch to the external meatus, supply- 
ing its cuticular lining and the outer surface of the membrana tympani. 
The middle meningeal [meningea magna] is the largest of the branches 
which supply the dura mater. It arises from the internal maxillary between the 
internal lateral ligament and the neck of the jaw, and passes vertically upward 
between the two roots of the auriculo-temporal nerve to the foramen spinosum of 
the sphenoid bone. On entering the cranium it divides into two branches, anterior 
and posterior. The anterior branch, the larger, crosses the great ala of the sphenoid 
and reaches the groove or canal in the anterior inferior angle of the parietal bone: 
it then divides into branches which spread out between the dura mater and internal 
surface of the cranium, some passing upward over the parietal bone as far as the 
vertex, and others backward to the occipital bone. The posterior branch crosses 
the squamous portion of the temporal, and on the inner surface of the parietal bone 
divides into branches which supply the posterior part of the dura mater and cranium. 
The branches of this vessel are distributed partly to the dura mater, but chiefly to 
the bones; they anastomose with the arteries of the opposite side and with the ante- 
rior and posterior meningeal. 
The middle meningeal, on entering the cranium, gives off the following collateral 
branches: 1, Numerous small vessels to the ganglion of the fifth nerve and to the 
dura mater in this situation; 2, a branch to the facial nerve (petrosal branch), 
which enters the hiatus Fallopii, supplies the facial nerve, and anastomoses with the 
stylo-mastoid branch of the posterior auricular artery; 3, orbital branches, which 
pass through the sphenoidal fissure, or through separate canals in the great wing of 
the sphenoid, to anastomose with the lachrymal or other branches of the ophthal- 
mic artery; 4, temporal branches, which pass through foramina in the great wing 
of the sphenoid and anastomose in the temporal fossa with the deep temporal 
arteries. 
The small meningeal [meningea parva] is sometimes derived from the pre- 
ceding. It enters the skull through the foramen ovale and supplies the Gasserian 
ganglion and dura mater. Before entering the cranium it gives off a branch to the 
nasal fossa, soft palate, and tonsil. 
The inferior dental descends with the dental nerve to the foramen on the inner 
side of the ramus of the jaw. It runs along the dental canal in the substance of 
the bone accompanied by the nerve, and opposite the first bicuspid tooth divides 
into two branches, incisor and mental: the former is continued forward beneath 
the incisor teeth as far as the symphysis, where it anastomoses with the artery of 
the opposite side; the mental branch escapes with the nerve at the mental foramen, 
supplies the structures composing the chin, and anastomoses with the submental, 
inferior labial, and inferior coronary arteries. As the dental artery enters the 
foramen it gives off a mylo-hyoid branch, which runs in the mylo-hyoid groove 
and ramifies on the under surface of the Mylo-hyoid muscle. The dental and 
incisor arteries during their course through the substance of the bone give off a 
few twigs which are lost in the cancellous tissue, and a series of branches which 
correspond in number to the roots of the teeth: these enter the minute apertures at 
the extremities of the fangs and supply the pulp of the teeth. 
Branches of the Second or Pterygoid Portion. 
Deep Temporal. 
Pterygoid. 
Masseteric. 
Buccal. 524 
THE ARTERIES. 
These branches are distributed, as their names imply, to the muscles in the 
maxillary region. 
The deep temporal branches, two in number, anterior and posterior, each 
occupies that part of the temporal'fossa indicated by its name. Ascending between 
the temporal muscle and pericranium, they supply that muscle and anastomose 
with the other temporal arteries, the anterior branch communicating with the 
lachrymal through small branches which perforate the malar bone and great wing 
of the sphenoid. 
The pterygoid branches, irregular in their number and origin, supply the 
Pterygoid muscles. 
The masseteric is a small branch which passes outward above the sigmoid 
notch of the lower jaw to the deep surface of the Masseter. It supplies that mus- 
cle and anastomoses with the masseteric branches of the facial and with the trans- 
verse facial artery. 
The buccal is a small branch which runs obliquely forward between the Inter- 
nal pterygoid and the ramus of the jaw to the outer surface of the Buccinator, to 
which it is distributed, anastomosing with branches of the facial artery. 
Alveolar. 
Infraorbital. 
Posterior or Descending Palatine. 
Branches of the Third or Spheno-maxillary Portion. 
Vidian. 
Ptery go-palatine. 
Nasal or Spheno-palatine. 
The alveolar or posterior dental branch is given off from the internal maxil- 
lary by a common branch with the infraorbital, and just as the trunk of the vessel 
is passing into the spheno-maxillary fossa. Descending upon the tuberosity of the 
•superior maxillary bone, it divides into numerous branches, some of which enter the 
posterior dental canals to supply the molar and bicuspid teeth and the lining of the 
antrum, and others are continued forward on the alveolar process to supply the gums. 
The infraorbital appears, from its direction, to be the continuation of the trunk 
of the internal maxillary. It arises from that vessel by a common trunk with the 
preceding branch, and runs along the infraorbital canal with the superior maxillary 
nerve, emerging upon the face at the infraorbital foramen beneath the Levator labii 
superioris. Whilst contained in the canal it gives off branches which ascend into 
the orbit and supply the Inferior rectus and Inferior oblique muscles and the lach- 
rymal gland. Other branches (anterior dental} descend through canals in the bone 
to supply the mucous membrane of the antrum and the front teeth of the upper 
jaw. On the face it supplies the lachrymal sac and inner angle of the orbit, anas- 
tomosing with the facial artery and nasal branch of the ophthalmic; and other 
branches descend beneath the Levator labii superioris and anastomose with the 
transverse facial and buccal branches. 
The four remaining branches arise from that portion of the internal maxillary 
i which is contained in the spheno-maxillary fossa. 
The descending palatine passes down along the posterior palatine canal with 
the anterior and middle palatine branches of Meckel's ganglion, and, emerging from 
the posterior palatine foramen, runs forward in a groove on the inner side of the 
alveolar border of the hard palate to the anterior palatine canal, where the terminal 
branch of the artery passes upward through the foramen of Stenson to anastomose 
with the naso-palatine artery. Its branches are distributed to the gums, the mucous 
membrane of the hard palate, and the palatine glands. Whilst it is contained in the 
palatine canal, it gives off branches which descend in the accessory palatine canals 
to supply the soft palate and tonsil, anastomosing with the ascending palatine artery. 
The Vidian branch passes backward along the Vidian canal with the Vidian 
nerve. It is distributed to the upper part of the pharynx and Eustachian tube, 
sending a small branch into the tympanum which anastomoses with the anterior 
tympanic. 
The pterygo-palatine is also a very small branch, which passes backward SURGICAL ANATOMY OF TRIANGLES OF THE NECK. 
525 
through the pterygo-palatine canal with the pharyngeal nerve, and is distributed 
to the upper part of the pharynx and Eustachian tube. 
The nasal or spheno-palatine passes through the spheno-palatine foramen into 
the cavity of the nose at the back part of the superior meatus, and divides into two 
branches: one, internal, the artery of the septum, passes obliquely downward and 
forward along the septum nasi, supplies the mucous membrane, and anastomoses in 
front with the terminal branch of the descending palatine. The external branches, 
two or three in number, supply the mucous membrane covering the lateral wall of 
the nose, the antrum, and the ethmoid and sphenoid cells. 
Surgical Anatomy of the Triangles of the Neck. 
The student having considered the relative anatomy of the large arteries of the 
neck and their branches, and the relations they bear to the veins and nerves, should 
now examine these structures collectively 
as they present themselves in certain re- 
gions of the neck, in each of which im- 
portant operations are constantly being per- 
formed. 
For this purpose the Sterno-mastoid or 
any other muscles that have been divided 
in the dissection of the vessels should be re- 
placed in their normal position; the head 
should be supported by placing a block at 
the back of the neck, and the face turned 
to the side opposite to that which is being 
examined. 
The side of the neck presents a some- 
what quadrilateral outline, limited above 
by the lower border of the body of the 
jaw and an imaginary line extending from 
the angle of the jaw to the mastoid process ; 
below, by the prominent uppei' border of 
the clavicle; in front, by the median line 
of the neck ; behind, by the anterior mar- 
gin of the Trapezius muscle. This space is 
subdivided into two large triangles by the Sterno-mastoid muscle, which passes 
obliquely across the neck from the sternum and clavicle below to the mastoid process 
above. The triangular space in front of this muscle is called the anterior triangle, 
and that behind it the posterior triangle. 
[Fig. 371. 
Jaw. 
Trapezius. 
Median line. 
Clavicle. 
Diagram of the Triangles of the Right Side of the 
Neck: i, digastric or submaxillary triangle; n, 
superior carotid triangle, or triangle of election; 
in, inferior carotid triangle, or triangle of neces- 
sity; iv, occipital triangle; v, subclavian trian- 
gle.-W. W. K.] 
Anterior Triangular Space. 
The Anterior Triangle is bounded in front by a line extending from the chin 
to the sternum; behind, by the anterior margin of the Sterno-mastoid; its base, 
directed upward, is formed by the lower border of the body of the jaw and a line 
extending from the angle of the jaw to the mastoid process; its apex is below, at 
the sternum. The space is covered by the integument, superficial fascia, Platysma, 
and deep fascia; it is crossed by branches of the facial and superficial cervical 
nerves, and is subdivided into three smaller triangles by the Digastric muscle above 
and the anterior belly of the Omo-hyoid below. These smaller triangles are named, 
from below upward, the inferior carotid, the superior carotid, and the submaxillary 
triangle. 
The Inferior Carotid Triangle [or "triangle of necessityin which we must tie 
the carotid if it is impossible to do so in the triangle of election] is bounded in front 
by the median line of the neck; behind, by the anterior margin of the Sterno-mastoid; 
above, by the anterior belly of the Omo-hyoid; and is covered by the integument, 526 
THE ARTERIES. 
superficial fascia, Platysma, and deep fascia, ramifying between which is seen the de- 
scending branch of the superficialis colli nerve. Beneath these superficial structures 
are the Sterno-hyoid and Sterno-thyroid muscles, which, together with the anterior 
margin of the Sterno-mastoid, conceal the lower part of the common carotid artery.1 
This vessel is enclosed within its sheath, together with the internal jugular vein 
and pneumogastric nerve; the vein lying on the outer side of the artery on the right 
side of the neck, but overlapping it or passing directly across it on the left side ; the 
nerve lying between the artery and vein, on a plane posterior to both. In front of 
the sheath are a few filaments descending from the loop of communication between 
the descendens and communicans noni; behind the sheath are seen the inferior thy- 
roid artery, the recurrent laryngeal nerve, and the sympathetic nerve; and on its 
inner side, the trachea, the thyroid gland, much more prominent in the female than 
in the male, and the lower part of the larynx. By cutting into the upper part of 
this space and slightly displacing the Sterno-mastoid muscle the common carotid 
artery may be tied below the Omo-hyoid muscle. 
The floor of the inferior carotid triangle is formed by the Longus colli muscle 
below and by the Scalenus anticus above (see Fig. 290, p. 384, and Fig. 297, p. 
397), between which muscles the vertebral artery and vein will be found passing 
into the foramen in the sixth transverse process; a small portion of the origin of 
the Rectus capitis anticus major may also be seen in the floor of the space. 
The Superior Carotid Triangle [or "triangle of electionin which we 
elect to tie the carotid if we have the choice] is bounded behind by the 
Sterno-mastoid; below, by the anterior belly of the Omo-hyoid; and above, by 
the posterior belly of the Digastric muscle. Its floor is formed by parts of the 
Thyro-hyoid, Hyo-glossus, and the inferior and middle Constrictor muscles of 
the pharynx, and it is covered by the integument, superficial fascia, Platysma, and 
deep fascia, ramifying between which are branches of the facial and superficialis 
colli nerves. This space contains the upper part of the common carotid artery, 
which bifurcates opposite the upper border of the thyroid cartilage into the external 
and internal carotid. These vessels are occasionally somewhat concealed from view 
by the anterior margin of the Sterno-mastoid muscle, which overlaps them. The 
external and internal carotids lie side by. side, the external being the more anterior 
of the two. The following branches of the external carotid are also met with in this 
space: the superior thyroid, running forward and downward; the lingual, directly 
forward ; the facial, forward and upward ; the occipital, backward ; and the ascend- 
ing pharyngeal, directly upward on the inner side of the internal carotid. The veins 
met with are-the internal jugular, which lies on the outer side of the common and 
internal carotid arteries, and veins corresponding to the above-mentioned branches 
of the external carotid-viz. the superior thyroid, the lingual, facial, ascending 
pharyngeal, and sometimes the occipital; all of which accompany their correspond- 
ing arteries and terminate in the internal jugular. The nerves in this space are the 
following : In front of the sheath of the common carotid is the descendens noni. The 
hypoglossal nerve crosses both carotids above, curving round the occipital artery at 
its origin. Within the sheath, between the artery and vein and behind both, is the 
pneumogastric nerve; behind the sheath, the sympathetic. On the outer side of 
the vessels the spinal accessory nerve runs for a short distance before it pierces the 
Sterno-mastoid muscle ; and on the inner side of the internal carotid, just below the 
hyoid bone, may be seen the superioi' laryngeal nerve, and, still more inferiorly, 
the external laryngeal nerve. The upper part of the larynx and lower part of the 
pharynx are also found in the front part of this space. 
The Submaxillary Triangle corresponds to the part of the neck immediately 
beneath the body of the jaw. It is bounded above by the lower border of the 
1 Therefore the carotid artery and jugular vein are not, strictly speaking, contained in this tri- 
angle, since they are covered by the Sterno-mastoid muscle; that is to say, lie behind the anterior 
border of that muscle, which forms the posterior border of the triangle. But as they lie very close to 
the structures which are really contained in the triangle, and whose position it is essential to remem- 
ber in operating on this part of the artery, it has seemed expedient to study the relations of all these 
parts together. SURGICAL ANATOMY OF TRIANGLES OF THE NECK. 
527 
body of the jaw and a line drawn from its angle to the mastoid process; below, 
by the posterior belly of the Digastric and Stylo-hyoid muscles; in front, by the 
middle line of the neck. The floor of this space is formed by the anterior belly 
of the Digastric, the Mylo-hyoid, and Hyo-glossus muscles, and it is covered by the 
integument, superficial fascia, Platysma, and deep fascia, ramifying between which 
are branches of the facial and ascending filaments of the superficial cervical nerve. 
This space contains in front the submaxillary gland, imbedded in the substance of 
which are the facial artery and vein and their glandular branches; beneath this 
gland, on the surface of the Mylo-hyoid muscle, are the submental artery and the 
mylo-hyoid artery and nerve. The back part of this space is separated from the 
front part by the stylo-maxillary ligament; it contains the external carotid artery, 
ascending deeply in the substance of the parotid gland; this vessel here lies in 
front of, and superficial to, the internal carotid, being crossed by the facial nerve, 
and gives off in its course the posterior auricular, temporal, and internal maxillary 
branches; more deeply is the internal carotid, the internal j ugular vein, and the 
pneumogastric nerve separated from the external carotid by the Stylo-glossus and 
Stylo-pharyngeus muscles and the glosso-pharyngeal nerve.1 
Posterior Triangular Space. 
The posterior triangular space is bounded in front by the Sterno-mastoid muscle, 
behind by the anterior margin of the Trapezius; its base corresponds to the upper bor- 
der of the clavicle, its apex to the occiput. The space is crossed about an inch above 
the clavicle by the posterior belly of the Omo-hyoid, which divides it unequally into 
two-an upper or occipital, and a lower or subclavian triangle. 
The Occipital, the larger of the two posterior triangles, is bounded in front by 
the Sterno-mastoid, behind by the Trapezius, below by the Omo-hyoid. Its floor 
is formed from above downward by the Splenius, Levator anguli scapulae, and the 
middle and posterior Scaleni muscles. It is covered by the integument, the Pla- 
tysma below, the superficial and deep fasciae, and crossed above by the ascending 
branches of the cervical plexus; the spinal accessory nerve is directed obliquely 
across the space from the Sterno-mastoid, which it pierces, to the under surface of 
the Trapezius; below, the descending branches of the cervical plexus and the trans- 
versalis colli artery and vein cross the space. A chain of lymphatic glands is also 
found running along the posterior border of the Sterno-mastoid from the mastoid 
process to the root of the neck. 
The Subclavian, the smaller of the two posterior triangles, is bounded above 
by the posterior belly of the Omo-hyoid, below by the clavicle, its base, directed 
forward, being formed by the Sterno-mastoid. The size of the subclavian triangle 
varies according to the extent of attachment of the clavicular portion of the Sterno- 
mastoid and Trapezius muscles, and also according to the height at which the Omo- 
hyoid crosses the neck above the clavicle. Its height also varies much according to 
the position of the arm, being much diminished by raising the limb, on account of 
the ascent of the clavicle, and increased by drawing the arm downward, when that 
bone is depressed. This space is covered by the integument, superficial and deep 
fasciae, and crossed by the descending branches of the cervical plexus. Just above 
the level of the clavicle the third portion of the subclavian artery curves outward 
and downward from the outer margin of the Scalenus anticus, across the first rib to 
the axilla. Sometimes this vessel rises as high as an inch and a half above the clav- 
icle or at any point intermediate between this and its usual level. Occasionally it 
passes in front of the Scalenus anticus or pierces the fibres of that muscle. The 
subclavian vein lies behind the clavicle, and is usually not seen in this space; but 
1 The same remark will apply to this triangle as was made about the inferior carotid triangle, 
rhe structures enumerated, as contained in the back part of the space, lie, strictly speaking, beneath 
jhe muscles which form the posterior boundary of the triangle; but as it is very important to bear in 
mind their close relation to the parotid gland and its boundaries (on account of the frequency of sur- 
gical operations on this gland), all these parts are spoken of together. 528 
THE ARTERIES. 
it occasionally rises as high up as the artery, and has even been seen to pass with 
that vessel behind the Scalenus anticus. The brachial plexus of nerves lies above 
the artery and in close contact with it. Passing transversely across the clavicular 
margin of the space are the suprascapular vessels, and, traversing its upper angle in 
the same direction, the transversalis colli artery and vein. The external jugular 
vein runs vertically downward behind the posterior border of the Sterno-mastoid, to 
terminate in the subclavian vein ; it receives the transverse cervical and suprascapu- 
lar veins, which occasionally form a plexus in front of the artery, and a small vein 
which crosses the clavicle from the cephalic. The small nerve to the Subclavius also 
crosses this triangle about its middle. A lymphatic gland is also found in the space. 
Its floor is formed by the first rib with the first digitation of the Serratus magnus. 
Internal Carotid Artery. 
The Internal Carotid Artery commences at the bifurcation of the common 
carotid, opposite the upper border of the thyroid cartilage, and runs perpendic- 
ularly upward, in front of the transverse processes of the three upper cervical 
vertebrae, to the carotid foramen in the petrous portion of the temporal bone. 
After ascending in it for a short distance it passes forward and inward through 
the carotid canal and enters the skull. It then ascends to the posterior clinoid 
process, curves forward through the cavernous sinus, and at the anterior clinoid 
process again turns upward, pierces the dura mater, and divides into its terminal 
branches. 
This vessel supplies the anterior part of the brain, the eye and its appendages, 
and sends branches to the forehead and nose. Its size in the adult is equal to that 
of the external carotid; in the child it is larger than that vessel. It is remarkable 
for the number of curvatures that it presents in different parts of its course. In 
its cervical portion it occasionally presents one or two flexures near the base of 
the skull, whilst through the rest of its extent it describes a double curvature 
which resembles the italic letter s placed horizontally. These curvatures most 
probably diminish the velocity of the current of blood by increasing the extent 
of surface over which it moves and adding to the amount of impediment pro- 
duced from friction. In considering the course and relations of this vessel it 
may be conveniently divided into four portions-a cervical, petrous, cavernous, 
and cerebral. 
Cervical Portion.-This portion of the internal carotid is superficial at its com- 
mencement, being contained in the superior carotid triangle, and lying on the same 
level as the external carotid, but behind that artery, overlapped by the Sterno- 
mastoid and covered by the Platysma, deep fascia, and integument: it then passes 
beneath the parotid gland, being crossed by the hypoglossal nerve, the Digastric 
and Stylo-hyoid muscles, and the external carotid and occipital arteries. Higher 
up it is separated from the external carotid by the Stylo-glossus and Stylo-pha- 
ryngeus muscles, the glosso-pharyngeal nerve, and pharyngeal branch of the 
pneumogastric. It is in relation behind with the Rectus capitis anticus major, 
the superior cervical ganglion of the sympathetic, and superior laryngeal nerve; 
externally, with the internal jugular vein and pneumogastric nerve; internally, 
with the pharynx, tonsil, the superior laryngeal nerve, and ascending pharyngeal 
artery. 
Petrous Portion.-When the internal carotid artery enters the canal in the 
petrous portion of the temporal bone, it first ascends a short distance, then curves 
forward and inward, and again ascends as it leaves the canal to enter the cavity of 
the skull. In this canal the artery lies at first anterior to the tympanum, from 
which it is separated by a thin bony lamella which is cribriform in the young sub- 
ject, and often absorbed in old age. It is separated from the bony wall of the 
carotid canal by a prolongation of dura mater, and is surrounded by filaments of 
the carotid plexus. 
Cavernous Portion.-The internal carotid artery in this part of its course at INTERNAL CAROTID ARTERY. 
529 
first ascends to the posterior clinoid process, then passes forward by the side of the 
body of the sphenoid bone, being situated on the inner wall of the cavernous sinus, 
in relation externally with the sixth nerve, surrounded by filaments of the sympa- 
thetic, and covered by the lining membrane of the sinus. 
Cerebral Portion.-On the inner side of the anterior clinoid process the inter- 
Fig. 372. 
The Internal Carotid and Vertebral Arteries, right side. 
nal carotid curves upward, perforates the dura mater bounding the sinus, and is 
received into a sheath of the arachnoid. This portion of the artery is on the outer 
side of the optic nerve; it lies at the inner extremity of the fissure of Sylvius, 
having the third nerve externally. 530 
THE ARTERIES. 
Plan of the Relations of the Internal Carotid Artery in the Neck. 
In Front. 
Skin, superficial and deep fasciae. 
Parotid gland. 
Stylo-glossus and Stylo-pharyngeus muscles. 
Glosso-pharyngeal nerve. 
Externally. 
Internal jugular vein. 
Pneumogastric nerve. 
Internal 
Carotid 
Artery. 
Internally. 
Pharynx. 
Superior laryngeal nerve. 
Ascending pharyngeal artery. 
Tonsil. 
Behind. 
Rectus capitis anticus major. 
Sympathetic. 
Superior laryngeal nerve. 
Peculiarities.-The length of the internal carotid varies according to the length of the 
neck, and also according to the point of bifurcation of the common carotid. Its origin some- 
times takes place from the arch of the aorta; in such rare instances this vessel has been found 
to be placed nearer the middle line of the neck than the external carotid, as far upward as the 
larynx when the latter vessel crossed the internal carotid. The course of the vessel, instead of 
being straight, may be very tortuous. A few instances are recorded in which this vessel was 
altogether absent: in one of these the common carotid passed up the neck and gave off the usual 
branches of the external carotid, the cranial portion of the internal carotid being replaced by two 
branches of the internal maxillary, which entered the skull through the foramen rotundum and 
ovale and joined to form a single vessel. 
Surgical Anatomy.-The cervical part of the internal carotid is sometimes wounded by a 
stab or gunshot wound in the neck, or even occasionally by a stab from within the mouth, as 
when a person receives a thrust from the end of a parasol or falls down with a tobacco-pipe in 
his mouth. In such cases a ligature should be applied to the common carotid. The relation of 
the internal carotid with the tonsil should be especially remembered, as instances have occurred 
in which the artery has been wounded during the operation of scarifying the tonsil, and fatal 
hemorrhage has supervened. 
The branches given off from the internal carotid are- 
From the Petrous Portion 
Tympanic (internal or deep). 
From the Cavernous Portion' 
Arterise receptaculi. 
Anterior Meningeal. 
Ophthalmic. 
Anterior Cerebral. 
Middle Cerebral. 
Posterior Communicating. 
Anterior Choroid. 
From the Cerebral Portion 
The cervical portion of the internal carotid gives off no branches. 
The tympanic is a small branch which enters the cavity of the tympanum 
through a minute foramen in the carotid canal, and anastomoses with the tympanic 
branch of the internal maxillary and with the stylo-mastoid artery. 
The arterise receptaculi are numerous small vessels derived from the internal 
carotid in the cavernous sinus; they supply the pituitary body, the Gasserian gan- 
glion, and the wTalls of the cavernous and inferior petrosal sinuses. One of these 
branches, distributed to the dura mater, is called the anterior meningeal; it anas- 
tomoses with the middle meningeal. 
The Ophthalmic Artery arises from the internal carotid just as that vessel is 
emerging from the cavernous sinus, on the inner side of the anterior clinoid process, 
and enters the orbit through the optic foramen below and on the outer side of the 
optic nerve. It then passes over the nerve to the inner wall of the orbit, and 
thence horizontally forward, beneath the lower border of the Superior oblique 
muscle, to the inner angle of the eye, where it divides into two terminal branches, 
the frontal and nasal. 
Branches.-The branches of this vessel may be divided into an orbital group, INTERNAL CAROTID ARTERY. 
531 
Fig. 373. 
Natal Palpilral 
Frontal 
Supra Orbital 
Anterior Jfflimoidud- 
Posterior Ethinoidal- 
Muscular ' 
-O-phtlval'niie 
-Internal Carotid, 
The Ophthalmic Artery and its Branches, the Roof of the Orhit having been removed. 
which are distributed to the orbit and surrounding parts; and an ocular group, 
which supply the muscles and globe of the eye. 
Orbital Group. 
Lachrymal. 
Supraorbital. 
Posterior Ethmoidal. 
Anterior Ethmoidal. 
Palpebral. 
Frontal. 
Nasal. 
Ocular Group. 
Muscular. 
Anterior Ciliary. 
Short Ciliary. 
Long Ciliary. 
Arteria centralis retinae. 
The lachrymal is the first, and one of the largest, branches derived from the 
ophthalmic, arising close to the optic foramen: not unfrequently it is given off from 
the artery before it enters the orbit. It accompanies the lachrymal nerve along the 
upper border of the External rectus muscle, and is distributed to the lachrymal 
gland. Its terminal branches, escaping from the gland, are distributed to the 
upper eyelid and conjunctiva, anastomosing with the palpebral arteries. The lach- 
rymal artery gives off one or two malar branches, one of which passes through a 
foramen in the malar bone to reach the temporal fossa, and anastomoses with the 
deep temporal arteries. The other appears on the cheek, and anastomoses with the 
transverse facial. A branch is also sent backward, through the sphenoidal fissure, 
to the dura mater, which anastomoses with a branch of the middle meningeal 
artery. 
Peculiarities.-The lachrymal artery is sometimes derived from one of the anterior branches 
of the middle meningeal artery. 
The supraorbital artery, the largest branch of the ophthalmic, arises from that 
vessel above the optic nerve. Ascending so as to rise above all the muscles of the 532 
THE ARTERIES. 
orbit, it passes forward with the frontal nerve, between the periosteum and Levator 
palpebrge, and, passing through the supraorbital foramen, divides into a superficial 
and a deep branch, which supply the muscles and integument of the forehead and 
pericranium, anastomosing with the temporal, the angular branch of the facial, and 
the artery of the opposite side. This artery in the orbit supplies the Superior 
rectus and the Levator palpebrm, sends a branch inward, across the pulley of the 
Superior oblique muscle, to supply the parts at the inner canthus, and at the supra- 
orbital foramen frequently transmits a branch to the diploe. 
The ethmoidal branches are two in number, posterior and anterior. The for- 
mer, which is the smaller, passes through the posterior ethmoidal foramen, supplies 
the posterior ethmoidal cells, and, entering the cranium, gives off a meningeal 
branch which supplies the adjacent dura mater and nasal branches, which descend 
into the nose through apertures in the cribriform plate, anastomosing with branches 
of the spheno-palatine. The anterior- ethmoidal artery accompanies the nasal nerve 
through the anterior ethmoidal foramen, supplies the anterior ethmoidal cells and 
frontal sinuses, and, entering the cranium, divides into a meningeal branch which 
supplies the adjacent dura mater, and a nasal branch which descends into the nose 
through an aperture in the cribriform plate. 
The palpebral arteries, two in number, superior and inferior, arise from the 
ophthalmic, opposite the pulley of the Superior oblique muscle; they encircle the 
eyelids near their free margin, forming a superior and an inferior arch, which lie 
between the Orbicularis muscle and tarsal cartilages, the superior palpebral inoscu- 
lating at the outer angle of the orbit with the orbital branch of the temporal 
artery, the inferior palpebral with the orbital branch of the infraorbital artery at 
the inner side of the lid. From this anastomosis a branch passes to the nasal duct, 
ramifying in its mucous membrane, as far as the inferior meatus. 
The frontal artery, one of the terminal branches of the ophthalmic, passes from 
the orbit at its inner angle, and, ascending on the forehead, supplies the muscles, 
integument, and pericranium, anastomosing with the supraorbital artery. 
The nasal artery, the other terminal branch of the ophthalmic, emerges from 
the orbit above the tendo oculi, and, after giving a branch to the lachrymal sac, 
divides into two, one of which anastomoses with the angular artery; the other 
branch, the dorsalis nasi, runs along the dorsum of the nose, supplies its entire 
surface, and anastomoses with the artery of the opposite side. 
The ciliary arteries are divisible into three groups-the short, long, and ante- 
rior. The short ciliary arteries, from twelve to fifteen in number, arise from the 
ophthalmic or some of its branches; they surround the optic nerve as they pass 
forward to the posterior part of the eyeball, pierce the sclerotic coat around the 
entrance of the nerve, and supply the choroid coat and ciliary processes. The long 
ciliary arteries, two in number, also pierce the posterior part of the sclerotic, and 
run forward along each side of the eyeball, between the sclerotic and choroid, to 
the ciliary ligament, where they divide into two branches; these form an arterial 
circle around the circumference of the iris, from which numerous radiating branches 
pass forward in its substance to its free margin, where they form a second arterial 
circle around its pupillary margin. The anterior ciliary arteries are derived from 
the muscular branches; they pierce the sclerotic a short distance from the cornea 
and terminate in the great arterial circle of the iris. 
The arteria centralis retinae is one of the smallest branches of the ophthalmic 
artery. It arises near the optic foramen, pierces the optic nerve obliquely, and 
runs forward, in the centre of its substance, to the retina, in which its branches are 
distributed as far forward as the ciliary processes. [See the description of the Eye.] 
In the human foetus a small vessel passes forward, through the vitreous humor, to 
the posterioi' surface of the capsule of the lens. 
The muscular branches, two in number, superior and inferior, supply the mus- 
cles of the eyeball. The superior, the smaller (often wanting), supplies the Levator 
palpebrm, Superior rectus, and Superior oblique. The inferior, more constant in 
its existence, passes forward between the optic nerve and Inferior rectus, and is INTERNAL CAROTID ARTERY. 
533 
distributed to the External, Internal, and Inferior recti, and Inferior oblique. This 
vessel gives off most of the anterior ciliary arteries. 
Fig. 374. 
Longitudinal 
Fissure 
The Arteries of the Base of the Brain. The right half of the Cerebellum and Pons have been removed. 
N. B.-It will be noticed that in the illustration the two anterior cerebral arteries have been drawn at a 
considerable distance from each other; this makes the anterior communicating artery appear very much 
longer than it really is. 
The cerebral branches of the internal carotid are-the anterior cerebral, the 
middle cerebral, the posterior communicating, and the anterior choroid. 
The anterior cerebral arises from the internal carotid at the inner extremity 
of the fissure of Sylvius. It passes forward in the great longitudinal fissure 534 
THE ARTERIES. 
between the two anterior lobes of the brain, being connected soon after its origin 
with the vessel of the opposite side by a short anastomosing trunk about two lines 
in length, the anterior communicating. The two anterior cerebral arteries, lying 
side by side, curve round the anterior border of the corpus callosum and run along 
its upper surface to its posterior part, where they terminate by anastomosing with 
the posterior cerebral arteries. They supply the olfactory and optic nerves, the 
under surface of the anterior lobes, the third ventricle, the anterior perforated space, 
the corpus callosum, and the internal surface of the hemispheres. 
The anterior communicating artery is a short branch, about two lines in 
length, but of moderate size, connecting together the two anterior cerebral arteries 
across the longitudinal fissure. Sometimes this vessel is wanting, the two arteries 
joining together to form a single trunk which afterward subdivides; or the vessel 
may be wholly or partially subdivided into two; frequently it is longer and smaller 
than usual. 
The middle cerebral [or Sylvian] artery, the largest branch of the internal 
carotid, passes obliquely outward along the fissure of Sylvius, within which it 
divides into three branches: an anterior, which supplies the pia mater, investing 
the surface of the anterior lobe; a posterior, which supplies the middle lobe; and 
a median branch, which supplies the small lobe at the outer extremity of the Sylvian 
fissure. Near its origin this vessel gives off numerous small branches which enter 
the locus perforatus anticus to be distributed to the corpus striatum. 
The posterior communicating artery arises from the back part of the inter- 
nal carotid, runs directly backward, and anastomoses with the posterior cerebral, a 
branch of the basilar. This artery varies considerably in size, being sometimes 
small, and occasionally so large that the posterior cerebral may be considered as 
arising from the internal carotid rather than from the basilar. It is frequently 
larger on one side than on the other side. 
The anterior choroid is a small but constant branch which arises from the back 
part of the internal carotid, near the posterior communicating artery. Passing back- 
ward and outward, it enters the descending horn of the lateral ventricle beneath the 
edge of the middle lobe of the brain. It is distributed to the hippocampus major, 
corpus fimbriatum, velum interpositum, and choroid plexus. 
[The Blood-vessels of the Brain. 
| The cerebral circulation is of such importance that a more detailed description 
of it seems desirable, especially in view of modern researches both in anatomy and 
pathology. 
The arteries of the brain are derived from the internal carotid and the vertebral. 
On the left side these vessels arise at such an angle that the blood-current is much 
more direct than on the right (Fig. 364, p. 503). Hence, probably, the larger size 
and development of the left hemisphere and the greater frequency of embolism and 
hemorrhage upon that side. 
At the base of the brain these four vessels form the circle of Willis. This con- 
sists of two sets of vessels : the anterior or carotid set, from which arise the anterior 
and middle cerebral arteries; and the posterior or vertebral set, consisting of the 
basilar and posterior cerebral arteries. Each set has the freest possible anasto- 
mosis from side to side, thus providing an abundant blood-supply in case of sudden 
blocking of one of its vessels. This is the more important since, as will be 
seen later, the peripheral arteries to the cortex and the ganglia have no anasto- 
mosis whatever. 
Antero-posteriorly, it is quite different. The anterior set of vessels are 
connected with the posterior by the two posterior communicating arteries, 
which are small anastomotic branches quite variable in their development. 
When of very small size or absent, the collateral circulation after ligature of 
the carotid is not uncommonly insufficient to supply the brain, and cerebral 
softening follows. THE BLOOD-VESSELS OF THE BRAIN. 
535 
Derived from the circle of Willis and its branches are two independent systems of 
nutrient arteries for the cerebrum, as demonstrated by Duret1 and Heubner2 simul- 
taneously. These are-(1) those arising from the circle of Willis and about an inch 
beyond it (the vessels arising 
within the dotted line in Fig. 
375), which supply the series 
of great ganglia at the base of 
the brain, and are known as the 
central or ganglionic arterial 
system; and (2) the branches 
distributed to the gray cortex 
of the cerebrum and the white 
medulla under it, which are 
called the cortical arterial sys- 
tem. 
These two systems, although 
they have a common origin from 
the same main trunks, are per- 
fectly independent of each other, 
having no peripheral communi- 
cation whatever. Their final 
branches are "terminal arte- 
ries" (Endarterien of Cohn- 
heim), ending independently 
and without anastomosis. 
Hence the dangers of vascular 
obstruction, especially beyond 
the circle of Willis, as there 
can be no compensatory collat- 
eral circulation established, and 
local wedge-shaped infarcts must 
arise. Similar terminal arteries 
exist in the kidney, spleen, lung, and retina, with similar dangers. This is in 
[Fig. 375. 
Diagram of the Distribution of the Vessels at the Base of the Cere- 
brum : CA, anterior cerebral artery : S, S, sylvian arteries; V, V, 
vertebral arteries; B, basilar; CP, CP, posterior cerebral arteries; 
1, 2, 3, 3, 4,4, groups of nutritive arteries. The line () limits 
the ganglionic vascular area (Charcot).] 
[Fig. 376. 
Transverse Section of the Cerebral Hemispheres, about 1 cm. behind the Optic Commissure. 
Ch, Chiasma; B, section of the optic tract; L, lenticular nucleus; 7, internal capsule; C, caudate nucleus; 
E, external capsule; T, claustrum; R, island of Reil; V, V, section of the lateral ventricle; P, P, anterior 
pillars of the fornix; 0, gray substance of the third ventricle. 
Vascular Areas: I, anterior cerebral artery; II, middle cerebral artery; III, posterior cerebral artery.-1, Inter- 
nal carotid artery; 2, Sylvian artery; 3, anterior cerebral artery; 4, 4, external arteries of the corpus striatum 
(lenticulo-striate artery); 5, 5, internal arteries of the corpus striatum (lenticular arteries); 6, arteries of the 
chiasma : 7, arteries of the commissure and anterior pillars of the fornix; 8, arteries of the convolutions of 
the insula and claustrum. The opto-striate artery is not represented in the figure (Duret).] 
1 Archives de Physiol, norm, et pathol., 1874. 
2 Centralb. medic. Wissensch., 1872. 536 
THE ARTERIES. 
marked contrast to the cerebral veins, for the veins of the surface and the sinuses 
at the base have a free anastomosis. 
1. The Ganglionic Arterial System.-The nutrient arteries of this system 
arise in four principal groups (Fig. 375): 1, The antero-median group, from the 
anterior communicating and anterior cerebrals, penetrating the lamina cinerea and 
supplying the head of the caudate nucleus. 2, The postero-median group, from the 
posterior communicating and posterior cerebrals, passing through the posterior per- 
forated space and supplying the walls of the third ventricle. 3, 3, The antero-lat- 
[Fig. 377. 
Vascular Areas of the Upper Surface of the Cerebrum. 
F, frontal lobe; P, parietal lobe; O, occipital lobe; s, end of the horizontal ramus of the fissure of Sylvius; c, 
central sulcus (fissure of Rolando); A, anterior central (ascending frontal) convolution; B, posterior central 
(ascending parietal) convolution; Flt F2, P3, superior, middle, ana inferior frontal convolutions; supe- 
rior and inferior frontal sulci; /3, vertical or transverse frontal fissure (sulcus praecentralis); Plt superior 
temporal lobule; P2, inferior temporal lobule, or gyrus supra-marginalis; P2', gyrus angularis; ip, intra-parie- 
tal fissure; cm, calloso-marginal fissure; po, po, parieto-occipital fissures; tlt superior temporal fissure; 
Oi, first occipital convolution; o, transverse occipital sulcus. 
Arteries: The line () marks the limits of the distribution of the anterior cerebral; the line 
( ) on the left side of the figure limits the distribution of the Sylvian artery; I, external 
and inferior frontal artery; II, anterior parietal artery; III, posterior parietal artery; IV, parieto-sphenoidal 
artery. The line ( ) on the right side of the figure limits the distribution of the posterior 
cerebral (Duret).] 
eral group on each side, from the middle cerebral or Sylvian artery, penetrating the 
anterior perforated space and supplying the corpora striata and anterior part of the 
optic thalamus. This is the most important group. They are the most frequent 
seat of cerebral hemorrhage, especially one branch, the lenticulo-striate, which pene- 
trates the third segment of the lenticular nucleus and extends to the caudate nucleus 
(Fig. 376, 4), and which, from the frequency with which hemorrhage occurs from it, 
Charcot calls "the artery of cerebral hemorrhage." 4, 4, The postero-lateral group, 
from the posterior cerebrals of each side, after they have wound round the crura cere- THE BLOOD-VESSELS OF THE BRATN. 
537 
bri, supplying the outer and posterior parts of the optic thalami and the corpora quad- 
rigemina and part of the crura cerebri. 
2. The Cortical Arterial System.-The three cerebral arteries (anterior, mid- 
dle, and posterior) supply each its own region, the middle or Sylvian artery being 
the most important. They run from the base of the brain to the sides and top, 
ramifying in the pia mater, and finally supply the gray cortex and underlying 
white matter. 
The anterior cerebral arises from the internal carotid. It runs forward and 
then upward around the anterior extremity of the corpus callosum in the great longi- 
tudinal fissure. To see it well the two hemispheres of the cerebrum must be well sep- 
arated. It has three main sets of branches (Figs. 377 and 378)-the first, the anterior 
[Fig. 378. 
Distribution of Vessds. 
The regions bounded by the line () represents the territories over which the branches of the Anterior Cere- 
bral Artery are distributed. 
I. Is the territory of the Interior and Anterior Frontal Artery. 
II. " " Internal and Middle " " 
III. " " Internal and Posterior " " 
The regions bounded by the line ) represent the territories over which the branches of the Pos- 
terior Cerebral Artery are distributed. 
II. Is the territory of the Posterior Temporal Artery. 
III. " " Occipital Artery. 
Fissures and Convolutions. 
CC, corpus callosum, longitudinally divided; Gf, gyrus foruicatus; H, gyrus hippocampi; h, sulcus hippocampi; 
U, uncinate gyrus; cm, sulcus calloso-marginalis; F„, median aspect of the first frontal convolution : c, ter- 
minal portion of the sulcus centralis, or fissure of Rolando; A, ascending frontal; B, ascending parietal con- 
volution ; Pj", precuneus; oz, cuneus ; po, parieto-occipital fissure ; o, sulcus occipitalis transversus; oc, cal- 
carine fissure; oc', superior, oc", inferior ramus of the same ; D, gyrus descendens; T4, gyrus occipito-tempo- 
ralis lateralis (lobulis fusiformis); T5, gyrus occipito-temporalis medialis (lobulus lingualis); Cf, collateral 
or occipito-temporal fissure.] 
Inner Surface of Right Hemisphere (after Ecker and Duret). 
and internal frontal, supplying the second and third frontal convolutions on their under 
and inner surfaces; the second, the middle and internal frontal, supplying the gyrus 
fornicatus, corpus callosum, first frontal convolution, the paracentral lobule, the upper 
surface of the frontal lobe, and the upper part of the ascending frontal convolution; 
and the third, supplying the quadrate lobe or precuneus. 
The middle cerebral or Sylvian artery arises also from the internal carotid, and 
is indeed its direct continuation. It is by far the largest and most important of the 
cerebral arteries. The edges of the fissure of Sylvius in which it runs must be 
separated to expose it well. A large number of smaller branches are first given 
off (Fig. 380, P, and Fig. 375, 3) in the anterior perforated space, which pass at 
once into the corpus striatum and anterior part of the optic thalamus. These 
belong to the ganglionic system of vessels supplying the ganglia at the base of the 538 
THE ARTERIES. 
brain (p. 536). One of them, the lenticulo-striate artery, has already been espe- 
cially referred to as the frequent source of cerebral hemorrhage. Opposite the 
island of Red (or Insula) the Sylvian artery divides into four principal branches, 
which belong to the cortical system. They run outward and upward and supply 
the sides and top of the cerebrum. The first, the inferior frontal (Fig. 380, 1), or 
the artery of Broca's convolution, supplies the third frontal convolution, and if 
obstructed (on the left side especially) produces local softening of this convolution 
and aphasia, or, as it is often called, "Broca's disease." The second (Fig. 380, 2) 
is the artery of the ascending frontal convolution. The third (Fig. 380, 3) is the 
[Fig. 379. 
Outer Surface of the Left Hemisphere (after Ecker and Duret). 
Distribution of Vessels. 
The region hounded by the line ( ) represents the territory over which branches of the Anterior Cerebral 
Artery are distributed. 
The anterior regions bounded by the line ( ) represent the territories over which branches of the 
Middle Cerebral Artery are distributed. 
I. Is the region of the External and Inferior Frontal Artery. 
II. " " Anterior Parietal Artery. 
III. " " Posterior Parietal Artery. 
IV. " " Parieto-sphenoidal Artery. 
The posterior and inferior region bounded by the line ( ) represents the territory over which 
branches of the Posterior Cerebral Artery are distributed. 
Fissures and Convolutions. 
F, Frontal lobe; P, parietal lobe; O, occipital lobe; T, temporo-sphenoidal lobe; S, fissure of Sylvius, S', hori- 
zontal, S", ascending ramus of the same: c, sulcus centralis or fissure of Rolando; A, anterior central or 
ascending frontal convolution; B, posterior central or ascending parietal convolution; F1( superior, F2, mid- 
dle, and Fs, inferior frontal convolutions; flt superior, and/2, inferior frontal sulcus;/3, sulcus praecentralis; 
Pi, superior parietal or postero-parietal lobule; P2, inferior parietal lobule, viz.: P2, gyrus supra-margin- 
alis; P2', gyrus angularis; ip, sulcus intra-parietalis; cm, termination of the calloso-marginal fissure; 
Oj, first, 02', second, 03, third occipital convolutions; po, parieto-occipital fissure; o,, sulcus occipitalis 
transversus; o2, sulcus occipitalis longitudinalis inferior; Tx, first, T2, second, T3, third temporo-sphe- 
noidal convolutions; tlt first, t2, second temporo-sphenoidal fissures.] 
artery of the ascending parietal convolution, and also supplies the precuneus. These 
two arteries run in front of and behind the fissure of Rolando, and supply the chief 
motor regions of the brain. The fourth (Fig. 380, 4, 5) supplies the supramarginal, 
angular, and first temporal convolutions. 
The posterior cerebral is the terminal branch of the basilar artery. It passes 
along the under surface of the occipital lobes of the cerebrum. It first gives oft' a THE BLOOD-VESSELS OF THE BRAIN. 
539 
number of small branches which pass into the posterior perforated space (Fig. 375, 
2), and after winding round the crura cerebri another set of small vessels (Fig. 375, 
4). Both these sets of vessels belong to the ganglionic system already described. 
After this it divides into three main branches (Figs. 378 and 381), which belong to 
the cortical, system of vessels-the first, the uncinate (or anterior temporal), dis- 
tributed to the gyrus uncinatus, the second to the temporo-sphenoidal lobe, and the 
third to the lingual lobule, the cuneus, and the occipital lobe. 
The nutrient branches from the arteries of the cortical system are distributed as 
follows: The large trunks do not divide into smaller, and these again farther on 
into still smaller, and so on, as in the rest of the body. The brain needs immedi- 
ate nourishment by small arteries even where the main large trunks run. Hence 
even the largest trunks give rise directly to very minute arteries, as well as to 
branches, which themselves quickly give rise to other very minute branches (Fig. 
382). 
[Fig. 380. 
Diagram showing the Area of Distribution of the Middle Cerebral Artery (semi-diagrammatic). 
S, Sylvian or middle cerebral artery; P, perforating (ganglionic) branches; 1, inferior frontal branch to Broca's 
convolution; 2, ascending frontal branch; 3, ascending parietal branch; 4 and 5, parieto-sphenoidal and 
sphenoidal branches; A, ascending frontal convolution; B, ascending parietal convolution; Fj, F?, F3, 
first, second, and third frontal convolutions; Pj, P2, P3, first, second, and third parietal convolutions; 
Tp T2, T3, first, second, and third temporo-sphenoidal convolutions; OL, occipital lobe; R, fissure of 
Rolando (Charcot).] 
Some of these minute arteries, the larger and longer ones, pass through the gray- 
layer to the white medullary matter of the brain, penetrating the centrum ovale to 
the depth of about one to two inches, and are therefore known as the medullary 
branches (Fig. 383, 1). The arteries on the summit of a convolution, as they pass 
through the gray matter on their way to the white, are vertical; those on the sides, 
oblique; those at the bottom, again, nearly vertical. The capillaries in the white 
medullary matter are in general vertical, and are excellent illustrations of ''terminal 
arteries." At their termination the descending branches of this, the cortical, system 
approach the ascending branches of the central or ganglionic system from the base 
of the brain, but the two systems do not anastomose. Between the two sets of ves- 
sels there is, as it were, a poorly-nourished neutral zone, in which lacunar softenings 
therefore often occur in old age, when the nutrition of the brain is impaired. 
' The other, shorter branches, go entirely to the thin gray layer on the cortex of 
the cerebrum, and are known as the cortical branches (Fig. 383, 2). They form 
meshes which supply the middle zone of the gray cortex very richly with blood 
(Fig. 383), but the inner and outer layers much less abundantly. 540 
THE ARTERIES. 
The fact that all these cerebral arteries and branches are so independent of each 
other as "terminal arteries" explains many cases of localized lesions1 which are 
especially apt to arise from obstruction to the blood-current by emboli followed by 
necrosis of that part of the cerebrum supplied by the obstructed vessel. This may 
[Fig. 381. 
View of the Brain from below (after Ecker and Duret). 
Distribution of Vessels. 
The region bounded by the line () represents the territory over which the Internal and Inferior Fronta. 
Branches of the Anterior Cerebral Artery are distributed. 
The regions bounded by the line ( ) represent the territories over which the branches of the Pos- 
terior Cerebral Artery are distributed. 
I. Is the region of the Anterior Temporal Artery. 
II. " " Posterior Temporal Artery. 
III. " " Occipital Artery. 
Fissures and Convolutions: F1, gyrus rectus; F2, middle frontal convolution; F3, inferior frontal convolution; 
/4, sulcus olfactorius;/5, sulcus orbitalis; T2, second or middle temporo-sphenoidal convolution; T'3, third 
or inferior temporo-sphenoidal convolution; T4, gyrus occipito-temporalis lateralis (lobulus fusiformis); 
T5, gyrus occipito-temporalis medialis (lobulus lingualis); Z4, sulcus occipito-temporalis inferior; t3, sulcus 
temporo-sphenoidalis inferior; t2, sulcus temporo-sphenoidalis medialis; po, parieto-occipital fissure; oc, 
calcarine fissure; H, gyrus hippocampi; U, gyrus uncinatus; Ch, optic chiasma; cc, corpora albicantia; 
KK, crura cerebri; C, corpus callosum.] 
readily be limited to one convolution or a group of convolutions, in which is located 
a special function, the abolition of which can be readily recognized during life. This 
is especially true of the Sylvian artery and its branches, for it supplies the region 
in which lie the motor centres (see Cerebral Localization and Topography, p. 681) 
and the faculty of speech (left third frontal or Broca's convolution). 
The arteries of the cerebellum are described on p. 549. 
The cerebral veins are described later (p. 618).] 
1 See Charcot, Localization of Cerebral and Spinal Diseases, for some excellent illustrations. THE BLOOD-VESSELS OF THE BRATN. 
541 
[Fig. 382. 
Mode of Division of the Cerebral Arteries: a, principal artery; b, primary branch; c, c, secondary branches 
1,1, medullary arteries; 2, 2, cortical arteries (Duret).] 
[Fig. 383. 
Distribution of Arteries to Gray and White Matter : 1,1, medullary branches passing directly through the gray 
matter to the white matter, and then terminating in branches that do not anastomose with their neigh- 
bors ("terminal arteries"); 1', medullary arteries in the sulcus between two convolutions; 2, 2, cortical 
arteries (Duret).] 
ARTERIES OF THE UPPER EXTREMITY. 
The artery which supplies the upper extremity continues as a single trunk from 
its commencement down to the elbow, but different portions of it have received dif- 
ferent names, according to the region through which it passes. That part of the 
vessel which extends from its origin to the lower border of the first rib is termed the 
subclavian; beyond this point to the lower border of the axilla it is termed the 542 
THE ARTERIES. 
axillary; and from the lower margin of the axillary space to the bend of the elbow 
it is termed brachial: here the single trunk terminates by dividing into two branches, 
the radial and ulnar-an arrangement precisely similar to what occurs in the lower 
limb. 
Subclavian Arteries. 
The Subclavian Artery on the right side arises from the arteria innominata 
opposite the right sterno-clavicular articulation; on the left side it arises from the 
arch of the aorta. It follows, therefore, that these two vessels must, in the first part 
of their course, differ in their length, their direction, and their relation with neigh- 
boring parts. 
In order to facilitate the description of these vessels, more especially in a surgical 
point of view, each subclavian artery has been divided into three parts. The first 
portion, on the right side, ascends obliquely outward from the origin of the vessel to 
the inner border of the Scalenus anticus; on the left side it ascends vertically to 
gain the inner border of that muscle; the second part passes outward behind the 
Scalenus anticus; and the third part passes from the outer margin of that muscle, 
beneath the clavicle, to the lower border of the first rib, where it becomes the axil- 
lary artery. The first portions of these two vessels differ so much in their course 
and in their relation with neighboring parts that they will be described separately. 
The second and third parts are precisely alike on both sides. 
First Part of the Kight Subclavian Artery (Figs. 364, 366, pp. 503, 513). 
The Right Subclavian Artery arises from the arteria innominata, opposite the 
right sterno-clavicular articulation, passes upward and outward across the root of the 
neck, and terminates at the inner margin of the Scalenus anticus muscle. In this 
part of its course it ascends a little above the clavicle, the extent to which it does so 
varying in different cases. It is covered in front by the integument, superficial 
fascia, Platysma, deep fascia, the clavicular origin of the Sterno-mastoid, the Sterno- 
hyoid, and Sterno-thyroid muscles, and another layer of the deep fascia. It is crossed 
by the internal jugular and vertebral veins, and by the pneumogastric, the cardiac 
branches of the sympathetic, and the phrenic nerve. Beneath, the artery is invested 
by the pleura., and behind, it is separated by a cellular interval from the Longus colli, 
the transverse process of the seventh cervical or first dorsal vertebra, and the sym- 
pathetic, the recurrent laryngeal nerve winding around the lower and back part of 
the vessel. The subclavian vein lies below the subclavian artery immediately 
behind the clavicle. 
Plan of Relations of First Portion of Right Subclavian Artery. 
In Front. 
Clavicular origin of Sterno-mastoid. 
Sterno-hyoid and Sterno-thyroid. 
Internal jugular and vertebral veins. 
Pneumogastric, cardiac, and phrenic nerves, 
Right 
Subclavian 
Artery. 
First Portion. 
Beneath. 
Pleura. 
Behind. 
Recurrent laryngeal nerve. 
Sympathetic. 
Longus colli. 
Transverse process of seventh cervical or first dorsal vertebra.1 
1 In five cases recently examined successively the artery was found to lie on the transverse process 
of the first dorsal. SUBCLAVIAN ARTERIES. 
543 
First Part of the Left Subclavian Artery (Fig. 364, p. 503). 
The Left Subclavian Artery arises from the end of the transverse portion of 
the arch of the aorta, opposite the fourth dorsal vertebra, and ascends to the inner 
margin of the first rib, behind the insertion of the Scalenus anticus muscle. This 
vessel is therefore longer than the right, situated more deeply in the cavity of the 
chest, and directed almost vertically upward, instead of arching outward like the 
vessel of the opposite side. 
It is in relation in front with the pleura, the left lung, the pneumogastric, cardiac, 
and phrenic nerves, which lie parallel with it, the left carotid artery, left internal 
jugular and innominate veins, and is covered by the Sterno-thyroid, Sterno-hyoid, 
and Sterno-mastoid muscles; behind, it is in relation with the oesophagus, thoracic 
duct, inferior cervical ganglion of the sympathetic, Longus colli, and vertebral 
column. To its inner side are the oesophagus, trachea, and thoracic duct; to its 
outer side, the pleura. 
Plan of Relations of First Portion of Left Subclavian Artery. 
In Front. 
Pleura and left lung. 
Pneumogastric, cardiac, and phrenic nerves. 
Left carotid artery. 
Left internal jugular and innominate veins. 
Sterno-thyroid, Sterno-hyoid, and Sterno-mastoid muscles. 
Inner Side. 
Trachea. 
(Esophagus. 
Thoracic duct. 
Left 
Subclavian 
Artery. 
Outer Side. 
Pleura. 
Behind. 
(Esophagus and thoracic duct. 
Inferior cervical ganglion of sympathetic. 
Longus colli and vertebral column. 
Second and Third Parts of the Subclavian Artery (Fig. 366, p. 513)., 
The Second Portion of the Subclavian Artery lies behind the Scalenus anti- 
cus muscle; it is very short, and forms the highest part of the arch described by 
that vessel. 
Relations.-It is covered in front by the integument, Platysma, Sterno-mas- 
toid, cervical fascia, and by the phrenic nerve, which is separated from the artery 
by the Scalenus anticus muscle; behind, it is in relation with the middle Scalenus; 
above, with the brachial plexus of nerves; below, with the pleura. The subclavian 
vein lies below and in front of the artery, separated from it by the Scalenus anticus. 
Plan of Relations of Second Portion of Subclavian Artery. 
In Front. 
Scalenus anticus. 
Phrenic nerve. 
Subclavian vein. 
Above. 
Brachial plexus. 
Subclavian 
Artery. 
Second 
portion. 
Below. 
Pleura. 
Behind. 
Pleura and middle Scalenus. 544 
THE ARTERIES. 
The Third Portion of the Subclavian Artery passes downward and outward 
from the outer margin of the Scalenus anticus to the lower border of the first rib, 
where it becomes the axillary artery. This portion of the vessel is the most super- 
ficial, and is contained in a triangular space the base of which is formed in front by 
the Sterno-mastoid, and the two sides by the Omo-hyoid above and the clavicle below. 
Relations.-It is covered in front by the integument, the superficial fascia, the 
Platysma, deep fascia, and by the clavicle, the Subclavius muscle, and the supra- 
scapular artery and vein; the clavicular descending branches of the cervical plexus 
and the nerve to the subclavius pass vertically downward in front of the artery. The 
external jugular vein crosses it at its inner side, and receives the suprascapular and 
transverse cervical veins, which occasionally form a plexus in front of it. The sub- 
clavian vein is belowr the artery, lying close behind the clavicle. Behind, it lies on 
the middle Scalenus muscle; above it and to its outer side is the brachial plexus and 
Omo-hyoid muscle; below, it rests on the outer surface of the first rib. 
Plan of Relations of Third Portion of Subclavian Artery. 
In Front. 
Cervical fascia. 
External jugular, suprascapular, and transverse cervical veins. 
Descending branches of cervical plexus ; nerve to Subclavius muscle. 
Subclavius muscle, suprascapular artery, and clavicle. 
Above. 
Brachial plexus. 
Omo-hyoid. 
Subclavian 
Artery. 
Third 
portion. 
Below. 
First rib. 
Behind. 
Scalenus medius. 
Peculiarities.-The subclavian arteries vary in their origin, their course, and the height 
to which they rise in the neck. 
The origin of the right subclavian from the innominate takes place, in some cases, above the 
sterno-clavicular articulation, and occasionally, but less frequently, in the cavity of the thorax 
below that joint; or the artery may arise as a separate trunk from the arch of the aorta. In 
such cases it may be either the first, second, third, or even the last, branch derived from that ves- 
sel ; in the majority of cases it is the first or last, rarely the second or third. When it is the first 
branch it occupies the ordinary position of the innominate artery ; when the second or third, it 
gains its usual position by passing behind the right carotid ; and when the last branch, it arises 
from the left extremity of the arch at its upper or back part, and passes obliquely toward the 
right side, usually behind the oesophagus and right carotid, sometimes between the oesophagus 
and trachea, to the upper border of the first rib, whence it follows its ordinary course. In very 
rare instances this vessel arises from the thoracic aorta as low down as the fourth dorsal verte- 
bra. Occasionally it perforates the anterior Scalenus; more rarely it passes in front of that 
muscle; sometimes the subclavian vein passes with the artery behind the Scalenus. The artery 
sometimes ascends as high as an inch and a half above the clavicle or any intermediate point 
between this and the upper border of the bone, the right subclavian usually ascending higher 
than the left. 
The left subclavian is occasionally joined at its origin with the left carotid. 
Surgical Anatomy.-The relations of the subclavian arteries of the two sides having been 
examined, the student should direct his attention to a consideration of the best position in which 
compression of the vessel may be effected, or in what situation a ligature may be best applied in 
cases of aneurism or wound. 
Compression of the subclavian artery is required in cases of operations about the 
shoulder, in the axilla, or at the upper part of the arm ■ and the student will observe that there 
is only one situation in which it can be effectually applied-viz. where the artery passes across 
the outer surface of the first rib. In order to compress the vessel in this situation the shoulder 
should be depressed, and the surgeon, grasping the side of the neck, should press with his thumb, 
in the angle formed by the posterior border of the Sterno-mastoid with the upper border of the 
clavicle, downward, backward, and inward against the rib; if from any cause the shoulder can- 
not be sufficiently depressed, pressure may be made from before backward, so as to compress the 
artery against the middle Scalenus and transverse process of the seventh cervical vertebra. In 
appropriate cases a preliminary incision may be made through the cervical fascia, and the finger 
may be pressed down directly upon the artery. 
Ligature of the subclavian artery may be required in cases of wounds or of aneurism SUBCLAVIAN ARTERIES. 
545 
in the axilla or in cases of aneurism on the cardiac side of the point of ligature; and the third 
part of the artery is that which is most favorable for an operation, on account of its being com- 
paratively superficial and most remote from the origin of the large branches. In those cases 
where the clavicle is not displaced this operation may be performed with comparative facility; 
but where the clavicle is pushed up by a large aneurismal tumor in the axilla the artery is placed 
at a great depth from the surface, which materially increases the difficulty of the operation. 
Under these circumstances it becomes a matter of importance to consider the height to which this 
vessel reaches above the bone. In ordinary cases its arch is about half an inch above the clav- 
icle, occasionally as high as an inch and a half, and sometimes so low as to be on a level with its 
upper border. If the clavicle is displaced, these variations will necessarily make the operation 
more or less difficult according as the vessel is more or less accessible. 
The chief points in the operation of tying the third portion of the subclavian artery are as 
follows : The patient being placed on a table in the horizontal position and the shoulder depressed 
as much as possible, the integument should be drawn downward upon the clavicle, and an incis- 
ion made through it upon that bone from the anterior border of the Trapezius to the posterior 
border of the Sterno-mastoid, to which may be added a short vertical incision meeting the pre- 
ceding in its centre. The object in drawing the skin downward is to avoid any risk of wounding 
the external jugular vein, for as it perforates the deep fascia above the clavicle it cannot be 
drawn downward with the skin. The Platysma and the cervical fascia should be divided upon a 
director, and if the interval between the Trapezius and Sterno-mastoid muscles be insufficient for 
the performance of the operation, a portion of one or both may be divided. The external jugular 
vein will now be seen toward the inner side of the wound: this and the suprascapular and trans- 
verse cervical veins which terminate in it should be held aside. If the external jugular vein is at 
all in the way and exposed to injury, it should be tied in two places and divided. The supra- 
scapular artery should be avoided, and the Omo-hyoid muscle must now be looked for and held 
aside if necessary. In the space beneath this muscle careful search must be made for the vessel: 
the deep fascia having been divided with the finger-nail or silver scalpel, the outer margin of the 
Scalenus anticus muscle must be felt for, and, the finger being guided by it to the first rib, the 
pulsation of the subclavian artery will be felt as it passes over the rib. The aneurism-needle 
may then be passed around the vessel from above downward and inward, so as to avoid including 
any of the branches of the brachial plexus. If the clavicle is so raised by the tumor that the 
application of the ligature cannot be effected in this situation, the artery may be tied above the 
first rib, or even behind the Scalenus muscle; the difficulties of the operation in such a case will 
be materially increased on account of the greater depth of the artery and the alteration in posi- 
tion of the surrounding parts. 
The second part of the subclavian artery, from being that portion which rises highest in the 
neck, has been considered favorable for the application of the ligature when it is difficult to tie 
the artery in the third part of its course. There are, however, many objections to the operation 
in this situation. It is necessary to divide the Scalenus anticus muscle, upon which lies the 
phrenic nerve, and at the inner side of which is situated the internal jugular vein, and a wound 
of either of these structures might lead to the most dangerous consequences. Again, the artery 
is in contact below with the pleura, which must also be avoided; and lastly, the proximity of so 
many of its larger branches arising internal to this point must be a still further objection to the 
operation. In cases, however, where the sac of an axillary aneurism encroaches on the neck it 
may be necessary to divide the outer half or two-thirds of the anterior Scalenus muscle, so as to 
place the ligature on the vessel at a greater distance from the sac. The operation is performed 
exactly in the same way as ligature of the third portion until the Scalenus anticus is exposed, 
when it is to be divided on a director (never to a greater extent than its outer two-thirds), and it 
immediately retracts. The operation is therefore merely an extension of ligature of the third 
portion of the vessel. 
In those cases of aneurism of the axillary or subclavian artery which encroach upon the outer 
portion of the Scalenus muscle to such an extent that a ligature cannot be applied in that situa- 
tion, it may be deemed advisable, as a last resource, to tie the first portion of the subclavian 
artery. On the left side this operation is almost impracticable ; the great depth of the artery from 
the surface, its intimate relation with the pleura, and its close proximity to the thoracic duct and 
to so many important veins and nerves, present a series of difficulties which it is next to impossi- 
ble to overcome.1 On the right side the operation is practicable, and has been performed, though 
never with success. The main objection to the operation in this situation is the smallness of the 
interval which usually exists between the commencement of the vessel and the origin of the near- 
est branch. This operation may be performed in the following manner : The patient being placed 
on the table in the horizontal position with the neck extended, an incision should be made par- 
allel with the posterior border of the inner part of the clavicle, and a second along the inner bor- 
der of the Sterno-mastoid, meeting the former at an angle. The sternal attachment of the Sterno- 
mastoid may now be divided on a director and turned outward ; a few small arteries and veins, 
and occasionally the anterior jugular, must be avoided, and the Sterno-hyoid and Sterno-thyroid 
muscles divided in the same manner as the preceding muscle. After tearing through the deep 
fascia with the finger-nail, the internal jugular vein will be seen crossing the subclavian artery; 
this should be pressed aside and the artery secured by passing the needle from below upward, by 
1 The operation was, however, performed in New York by Dr. J. K. Rodgers, and the case is related 
in A System of Surgery, edited by T. Holmes, 2d ed. vol. iii. pp. 620, etc. 546 
THE ARTERIES. 
which the pleura is more effectually avoided. The exact position of the vagus nerve, the recur- 
rent laryngeal, the phrenic and sympathetic nerves should be remembered, and the ligature 
should be applied near the origin of the vertebral, in order to afford as much room as possible for 
the formation of a coagulum between the ligature and the origin of the vessel. It should be 
remembered that the right subclavian artery is occasionally deeply placed in the first part of its 
course, when it arises from the left side of the aortic arch, and passes in such cases behind the 
oesophagus or between it and the trachea. 
Collateral Circulation.-After ligature of the third part of the subclavian artery the col- 
lateral circulation is mainly established by three sets of vessels, thus described in a dissection : 
" 1. A posterior set, consisting of the suprascapular and posterior scapular branches of the 
subclavian, which anastomosed with the median branch from the subscapular from the axillary. 
" 2. An internal set, produced by the connection of the internal mammary on the one hand 
with the short and long thoracic arteries and the median branch from the subscapular on the other. 
" A middle or axillary set, which consisted of a number of small vessels derived from branches 
of the subclavian above, and passing through the axilla, to terminate either in the main trunk 
or some of the branches of the axillary below. This last set presented most conspicuously the 
fteculiar character of newly-formed-or, rather, dilated-arteries, being excessively tortuous and 
brming a complete plexus. 
" The chief agent in the restoration of the axillary artery below the tumor was the subscapu- 
lar artery, which communicated most freely with the internal mammary, suprascapular, and 
posterior scapular branches of the subclavian, from all of which it received so great an influx of 
blood as to dilate it to three times its natural size." 1 
Branches of the Subclavian Artery. 
These are four in number: three arising from the first portion of the vessel, 
the vertebral, the internal mammary, and the thyroid axis, and one from the sec- 
ond portion, the superior intercostal. The vertebral arises from the upper and 
back part of the first portion of the artery; 
the thyroid axis, from the front; and the 
internal mammary, from the under part of 
this vessel. The superior intercostal is given 
off from the upper and back part of the sec- 
ond portion of the artery. On the left side 
the second portion usually gives off no branch, 
the superior intercostal arising from the first 
portion of the vessel. On both sides of the 
body the first three branches arise close to- 
gether at the inner margin of the Scalenus 
anticus, in the majority of cases a free inter- 
val of half an inch to an inch existing be- 
tween the commencement of the artery and 
the origin of the nearest branch; in a smaller 
number of cases an interval of more than 
• an inch exists, never exceeding an inch and 
three-quarters. In a very few instances the interval had been found to be less than 
half an inch. 
The Vertebral Artery (Fig. 372, p. 529) is generally the first and largest branch 
of the subclavian; it arises from the upper and back part of the first portion of the 
vessel, and, passing upward, enters the foramen in the transverse process of the 
sixth cervical vertebra,2 and ascends through the foramina in the transverse pro- 
cesses of all the vertebrae above this. Above the upper border of the axis it inclines 
outward and upward to the foramen in the transverse process of the atlas, through 
which it passes; it then winds backward behind its articular process, runs in a deep 
groove on the upper surface of the posterior arch of this bone, and, piercing the pos- 
terior occipito-atloid ligament and dura mater, enters the skull through the foramen 
magnum. It then passes forward and upward to the front of the medulla oblongata, 
Fig. 384. 
Plan of the Right Subclavian 
1 Guy's Hospital Reports, vol. i., 1836, case of axillary aneurism, in which Mr. Aston Key had tied 
the subclavian artery on the outer edge of the Scalenus muscle twelve years previously. 
2 The vertebral artery sometimes enters the foramen in the transverse process of the fifth ver- 
tebra. Dr. Smyth, who tied this artery in the living subject, found it, in one of his dissections, pass- 
ing into the foramen in the seventh vertebra. [Very rarely it may enter the fourth.] SUBCLAVIAN ARTERIES. 
547 
and unites with the vessel of the opposite side at the lower border of the pons Varolii 
to form the basilar artery. 
At its origin it is situated behind the internal jugular vein and inferior thyroid 
artery, and near the spine lies between the Longus colli and Scalenus anticus mus- 
cles, having the thoracic duct in front of it on the left side. Within the foramina 
formed by the transverse processes of the vertebrae it is accompanied by a plexus 
of nerves from the sympathetic, and lies between the vertebral vein, which is in 
front, and the cervical nerves, which issue from the intervertebral foramina behind 
it. Whilst winding round the articular process of the atlas it is contained in a tri- 
angular space {suboccipital triangle} formed by the Rectus capitis posticus major, 
the Superior and the Inferior oblique muscles, and at this point is covered by the 
Complexus muscles. Within the skull, as it winds round the medulla oblongata, 
it is placed between* the hypoglossal nerve and the anterior root of the suboccipital 
nerve, and finally lies between the dura mater covering the basilar process of the 
occipital bone and the anterior surface of the medulla oblongata. 
Branches.-These may be divided into two sets-those given off in the neck, 
and those within the cranium. 
Cervical Branches. 
Lateral Spinal. 
Muscular. 
Cranial Branches. 
Posterior Meningeal. 
Anterior Spinal. 
Posterior Spinal. 
Posterior Inferior Cerebellar. 
The lateral spinal branches enter the spinal canal through the intervertebral 
foramina, each dividing into two branches. Of these, one passes along the roots of 
[Fig. 385. 
Anterior median artery: 
af, Arteries of the anterior median fissure. 
ac, Artery of the anterior commissure. 
1,1', 1", Anterior, median, and posterior 
branches. 
i, Internal group of cells. 
m, Median area. 
ia, Internal anterior root-artery. 
a, Anterior group of cells. 
ea, External anterior root-artery. 
3, 3', Internal and external branches. 
ar, Antero-lateral artery. 
4,4', 4", Anterior, median, and posterior 
branches. 
al, Antero-lateral group of cells. 
c, Central group of cells. 
pl, Postero-lateral group of cells. 
mr, Median lateral artery. 
5, o', Anterior and posterior branches. 
pr, Posterior lateral arteries. 
pa, Posterior root-arteries. 
6, 6', 6", Arteries of posterior horns. 
mp, External posterior artery. 
ip, Internal posterior artery. 
g, Arteries of the column of Goll. 
vc, Vesicular column of Clarke. 
pc, Artery of the posterior commissure. 
ca, Central artery. 
2,2', 2", Anterior, median, and posterior 
branches. 
cc, Central canal or " ventricle of the cord." 
Diagram of the Distribution of the Blood-vessels and grouping of Ganglion-cells in the Spinal Cord 
(Young).] 
the nerves to supply the spinal cord and its membranes, anastomosing with the other 
spinal arteries; the other is distributed to the posterior surface of the bodies of the 
vertebrae. 
Muscular branches are given off to the deep muscles of the neck, where the 548 
THE ARTERIES. 
vertebral artery curves round the articular process of the atlas. They anastomose 
with the occipital and deep cervical arteries. 
The posterior meningeal are one or two small branches given off from the 
[Fig. 386. 
Section of the Medulla Oblongata, showing the Distribution of the Vessels. 
a, Anterior group of cells of the hypoglossal nu- 
cleus. 
al, Antero-lateral group of the same. 
i, Internal group of the same. 
if, Internal accessory facial nuclei. 
c, Central artery. 
3, 3', 3", Branches to the hypoglossal and external 
accessory facial nuclei. 
pl, Postero-lateral group of cells of the hypoglossal 
nucleus. 
ef, External accessory facial nucleus. 
mp, Median posterior artery. 
4,4', 4", Branches to the external accessory facial 
and pneumogastric nuclei. 
nv, Nucleus of the vagus. 
f, Fasciculus rotundus. 
vin, Inferior portion of the posterior median acoustic 
nucleus. 
ep, External posterior artery. 
G, Column of Goll. 
cn, Clavate nucleus. 
pr, Posterior root-zone. The direct cerebellar tract 
formsa thin band lying external to the column 
of Goll and posterior root-zone. 
pla, The posterior lateral arteries of the medulla ob- 
longata. 
tn, Triangular nucleus. 
x, Pneumogastric nerve. 
lr, Lateral root-artery (vagus). 
5, Branch to the rest)form body and the inner 
division of the inferior cerebellar peduncle. 
5', 5", Branches to the nucleus of the vagus. 
at, Ascending root of the trigeminus. 
sg, The substantia gelatinosa. 
pic, Posterior nucleus of the lateral column. 
ale, Anterior " " " " 
mfa, The middle lateral artery of the medulla oblon- 
gata. 
ala, Anterior lateral artery of the same. 
no, Parolivary body. 
O, Olivary body. 
ar, Anterior root-artery (hypoglossal). 
2, Branch to the olivary body. 
2', Branches to the Jormatio reticularis. 
xii, Hypoglossal nerve. 
p, Pyramidal arteries. 
P, Anterior pyramid. 
pn, Nucleus of the arciform fibres. 
r, Artery of the median raph6. 
1,1,1, Branches to the jormatio reticularis. 
1', Branch to the olivary body (O). 
1", Branches to the hypoglossal nucleus. 
V", Branches to the floor of the fourth ventricle 
and to the internal inferior nuclei of the 
facial («/). 
np, Nucleus of the pyramid (Ross).] 
vertebral opposite the foramen magnum. They ramify between the bone and dura 
mater in the cerebellar fossae and supply the falx cerebelli. SUBCLAVIAN ARTERIES. 
549 
The anterior spinal is a small branch, larger than the posterior spinal, which 
arises near the termination of the vertebral, and, descending in front of the medulla 
oblongata, unites with its fellow of the opposite side at about the level of the for- 
amen magnum. The single trunk thus formed descends a short distance on the front 
of the spinal cord, and joins with a succession of small branches which enter the 
spinal canal through some of the intervertebral foramina ; these branches are derived 
from the vertebral and ascending cervical of the inferior thyroid in the neck ; from 
the intercostal in the dorsal region ; and from the lumbar, ilio-lumbar, and lateral 
sacral arteries in the lower part of the spine. They unite, by means of ascending 
and descending branches, to form a single anterior median artery, which extends as 
far as the lower part of the spinal cord. This vessel is placed beneath the pia mater 
along the anterior median fissure; it supplies that membrane and the substance of 
the cord, and sends off branches at its lower part to be distributed to the cauda 
equina. 
The posterior spinal arises from the vertebral at the side of the medulla oblon- 
gata ; passing backward to the posterior aspect of the spinal cord, it descends on 
either side, lying behind the posterior roots of the spinal nerves, and is reinforced 
by a succession of small branches which enter the spinal canal through the inter- 
vertebral foramina, and by which it is continued to the lower part of the cord and 
to the cauda equina. Branches from these vessels form a free anastomosis round the 
posterior roots of the spinal nerves, and communicate by means of very tortuous 
transverse branches with the vessel of the opposite side. At its commencement it 
gives off an ascending branch which terminates on the side of the fourth ventricle. 
The posterior inferior cerebellar artery (Fig. 374, p. 533), the largest branch 
of the vertebral, winds backward round the upper part of the medulla oblongata, 
passing between the origin of the pneumogastric and spinal accessory nerves over 
the restiform body to the under surface of the cerebellum, where it divides into two 
branches: an internal one, which is continued backward to the notch between the 
two hemispheres of the cerebellum; and an external one, which supplies the under 
surface of the cerebellum as far as its outer border, where it anastomoses with the 
superior cerebellar. Branches from this artery supply the choroid plexus of the 
fourth ventricle. 
The Basilar Artery, so named from its position at the base of the skull, is a sin- 
gle trunk formed by the junction of the two vertebral arteries ; it extends from the 
posterior to the anterior border of the pons Varolii, where it divides into two ter- 
minal branches, the posterior cerebral arteries. Its branches are, on each side, the 
following: 
Transverse. 
Anterior Inferior Cerebellar. 
Superior Cerebellar. 
Posterior Cerebral. 
The transverse branches supply the pons Varolii and adjacent parts of the 
brain; one {internal auditory) accompanies the auditory nerve into the internal 
auditory meatus; and another, of larger size, passes along the crus cerebelli, to be 
distributed to the anterior border of the under surface of the cerebellum. It is 
called the anterior inferior cerebellar artery. 
The superior cerebellar arteries arise near the termination of the basilar. They 
wind round the crus cerebri close to the fourth nerve, and, arriving at the upper sur- 
face of the cerebellum, divide into branches which ramify in the pia mater and anas- 
tomose with the inferior cerebellar. Several branches are given to the pineal gland 
and also to the velum interpositum. 
The posterior cerebral arteries, the two terminal branches of the basilar, are 
larger than the preceding, from which they are separated near their origin by the 
third nerve. Winding round the crus cerebri, they pass to the under surface of 
the posterior lobes of the cerebrum, which they supply, anastomosing with the ante- 
rior and middle cerebral arteries. Near their origin they receive the posterioi' com- 
municating arteries from the internal carotid, and give off numerous branches which 
enter the posterior perforated space: they also give off a branch, the posterior cho- 550 
THE ARTERIES. 
roid, which supplies the velum interpositum and choroid plexus, entering the interior 
of the brain beneath the posterior border of the corpus callosum. 
Circle of Willis.-The remarkable anastomosis which exists between the 
branches of the internal carotid and vertebral arteries at the base of the brain con- 
stitutes the circle of Willis. It is formed in front by the anterior cerebral arteries, 
branches of the internal carotid, which are connected together by the anterior com- 
municating : behind, by the two posterior cerebrals, branches of the basilar, which 
are connected to the internal carotid by the posterior communicating (Fig. 372, p. 
529). It is by this anastomosis that the cerebral circulation is equalized and pro- 
vision made for effectually carrying it on if one or more of the branches are obliter- 
ated. The parts of the brain included within this arterial circle are-the lamina 
cinerea, the commissure of the optic nerves, the infundibulum, the tuber cinereum, 
the corpora albicantia, and the posterior perforated space. 
The Thyroid Axis (Fig. 366, p. 513) is a short thick trunk which arises from 
the fore part of the first portion of the subclavian artery, close to the inner border 
of the Scalenus anticus muscle, and divides, almost immediately after its origin, into 
three branches-the inferior thyroid, suprascapular, and transversalis colli. 
The Inferior Thyroid Artery passes upward, in a serpentine course, behind the 
sheath of the common carotid vessel and sympathetic nerve (the middle cervical gan- 
glion resting upon it), and is distributed to the under surface of the thyroid gland, 
anastomosing with the superior thyroid and with the corresponding artery of the 
opposite side. Its branches are the 
Laryngeal. 
Tracheal. 
(Esophageal. 
Ascending Cervical. 
Muscular. 
The laryngeal branch (inferior laryngeal) ascends upon the trachea to the back 
part of the larynx, in company with the recurrent laryngeal nerve, and supplies the 
muscles and mucous membrane of this part. 
The tracheal branches are distributed upon the trachea, anastomosing below 
with the bronchial arteries. 
The oesophageal branches are distributed to the oesophagus. 
The ascending cervical is a small branch which arises from the inferior thyroid 
just where that vessel is passing behind the common carotid artery, and runs up on 
the anterior tubercles of the transverse processes of the cervical vertebrae in the 
interval between the Scalenus anticus and Rectus capitis anticus major. It gives 
branches to the muscles of the neck, which communicate with those sent out from 
the vertebral, and sends one or two through the intervertebral foramina, along the 
cervical nerves, to supply the bodies of the vertebrae, the spinal cord, and its mem- 
branes. It anastomoses with the ascending pharyngeal artery. 
The muscular branches supply the depressors of the hyoid bone, the Longus 
colli, the Scalenus anticus, and the Inferior constrictor of the pharynx. 
The Suprascapular Artery (transversalis humeri), smaller than the transver- 
salis colli, passes obliquely from within outward across the root of the neck. It at 
first lies on the lower part of the Scalenus anticus, being covered by the Sterno- 
mastoid; it then crosses the subclavian artery, and runs outward behind and par- 
allel with the clavicle and Subclavius muscle, and beneath the posterior belly of the 
Omo-hyoid, to the superior border of the scapula, where it passes over the transverse 
ligament of the scapula to the supraspinous fossa. In this situation it lies close to 
the bone, and ramifies between it and the Supraspinatus muscle, to which it is mainly 
distributed, giving off a communicating branch which crosses the neck of the scapula 
to reach the infraspinous fossa, where it anastomoses with the dorsal branch of the 
subscapular artery. Besides distributing branches to the Sterno-mastoid and neigh- 
boring muscles, it gives off a supra-acromial branch, which, piercing the Trapezius 
muscle, supplies the cutaneous surface of the acromion, anastomosing with the acro- 
mial thoracic and posterior circumflex arteries. As the artery passes over the trans- 
verse ligament of the scapula a branch descends into the subscapular fossa, ramifies SUBCLAVIAN ARTERIES. 
551 
f 
beneath that muscle, and anastomoses with the posterior and subscapular arteries. 
It also supplies the shoulder-joint. 
The Transversalis colli passes transversely outward, across the upper part of 
the subclavian triangle, to the anterior margin of the Trapezius muscle, beneath 
which it divides into two branches, the superficial cervical and the posterior scapu- 
lar. In its passage across the neck it crosses in front of the Scaleni muscles and 
the brachial plexus, between 
the divisions of which it some- 
times passes, and is covered by 
the Platysma, Sterno-mastoid, 
Omo-hyoid, and Trapezius mus- 
cles. 
The superficial cervical 
ascends beneath the anterior 
margin of the Trapezius, dis- 
tributing branches to it and 
to the neighboring muscles and 
glands in the neck, and anasto- 
moses with the superficial branch 
of the arteria princeps cervicis. 
The posterior scapular, the 
continuation of the transversalis 
colli, passes beneath the Levator 
anguli scapulae to the superior 
angle of the scapula, and de- 
scends along the posterior border 
of that bone as far as the inferior 
angle, where it anastomoses with 
the subscapular branch of the 
axillary. In its course it is cov- 
ered by the Rhomboid muscles, supplying these, the Latissimus dorsi, and [the] Tra- 
pezius, and anastomosing with the suprascapular and subscapular arteries and with 
the posterior branches of some of the intercostal arteries. 
Peculiarities.-The superficial cervical frequently arises as a separate branch from the 
thyroid axis, and the posterior scapular from the third, more rarely from the second, part of 
the subclavian. 
The Internal Mammary arises from the under surface of the first portion of 
the subclavian artery, opposite the thyroid axis. It descends behind the clavicle to 
the inner surface of the anterior wall of the chest, resting against the costal cartilages 
a short distance from the margin of the sternum, and at the interval between the sixth 
and seventh cartilages divides into two branches, the musculo-phrenic and superior 
epigastric. 
At its origin it is covered by the internal jugular and subclavian veins and 
crossed by the phrenic nerve. In the upper part of the thorax it lies against the 
costal cartilages and internal Intercostal muscles in front, and is covered by the 
pleura behind. At the lower part of the thorax the Triangularis sterni separates 
the artery from the pleura. It is accompanied by two veins, which join at the 
upper part of the thorax into a single trunk. 
The branches of the internal mammary are the 
Fig. 387. 
Posterior 'Scafiular 
Supra •Ptafiular 
Acromial Branch 
f Thoracico-Acromialis 
I 
Antenor 
Circumflex 
The Scapular and Circumflex Arteries. 
Termination: of 
Subscapular. 
Comes nervi phrenici (superior phrenic). 
Mediastinal. 
Pericardiac. 
• Sternal. 
Anterior Intercostal. 
Perforating. 
Musculo-phrenic. 
Superior Epigastric. 
The comes nervi phrenici (superior phrenic) is a long slender branch which 
accompanies the phrenic nerve, between the pleura and pericardium, to the Dia- 552 
THE ARTERIES. 
phragm, to which it is distributed, anastomosing with the other phrenic arteries 
from the internal mammary and abdominal aorta. 
The mediastinal branches are small vessels which are distributed to the areolar 
tissue in the anterior mediastinum and the remains of the thymus gland. 
The pericardiac branches supply the upper part of the pericardium, the lower 
part receiving branches from the musculo-phrenic artery. 
The sternal branches are distributed to the Triangularis sterni and to the poste- 
rior surface of the sternum. 
The mediastinal, pericardiac, and sternal branches, together with some twigs 
from the comes nervi phrenici, anastomose with branches from the intercostal and 
bronchial arteries, and form a minute plexus beneath the pleura which has been 
named by Turner the subpleural mediastinal plexus. 
The anterior intercostal arteries supply the five or six upper intercostal spaces. 
The branch corresponding to each space passes outward, and soon divides into two, 
which run along the opposite border of the ribs and inosculate with the intercostal 
arteries from the aorta. They are at first situated between the pleura and the inter- 
nal Intercostal muscles, and then between the internal and external Intercostal mus- 
cles. They supply the Intercostal and Pectoral muscles and the mammary gland. 
The perforating arteries correspond to the five or six upper intercostal spaces. 
They arise from the internal mammary, pass forward through the intercostal spaces, 
and, curving outward, supply the Pectoralis major and the integument. Those which 
correspond to the first three spaces are distributed to the mammary gland. In females 
during lactation these branches are of large size. 
The musculo-phrenic artery is directed obliquely downward and outward, 
behind the cartilages of the false ribs, perforating the Diaphragm at the eighth 
or ninth rib, and terminating, considerably reduced in size, opposite the last inter- 
costal space. It gives off anterior intercostal arteries to each of the intercostal 
spaces across which it passes; these diminish in size as the spaces decrease in 
length, and are distributed in a manner precisely similar to the anterior intercos- 
tals from the internal mammary. The musculo-phrenic also gives branches to the 
lower part of the pericardium and others which run backward to the Diaphragm 
and downward to the abdominal muscles. 
The superior epigastric continues in the original direction of the internal mam- 
mary, descends behind the Rectus muscle, and, perforating its sheath, divides into 
branches which supply the Rectus, anastomosing with the epigastric artery from the 
external iliac. Some vessels perforate the sheath of the Rectus and supply the mus- 
cles of the abdomen and the integument, and a small branch which passes inward 
upon the side of the ensiform appendix anastomoses in front of that cartilage with 
the artery of the opposite side. 
The Superior Intercostal (Fig. 372, p. 529) arises from the upper and back part 
of the subclavian artery, behind the anterior Scalenus on the right side and to the 
inner side of the muscle on the left side. Passing backward, it gives off the deep 
cervical branch, and then descends behind the pleura in front of the necks of the 
first two ribs and inosculates with the first aortic intercostal.1 In the first intercostal 
space it gives off a branch which is distributed in a manner similar to the distribu- 
tion of the aortic intercostals. The branch for the second intercostal space usually 
joins with one from the aortic intercostal. Each intercostal gives off a branch to 
the posterior spinal muscles, and a small one which passes through the correspond- 
ing intervertebral foramen to the spinal cord and its membranes. 
The deep cervical branch (profunda cervicis) arises in most cases from the 
superior intercostal, and is analogous to the posterior branch of an aortic inter- 
costal artery. Passing backward, between the transverse process of the seventh 
cervical vertebra and the first rib, it runs up the back part of the neck, between 
the Complexus and Semispinalis colli muscles, as high as the axis, supplying these 
and adjacent muscles, and anastomosing with the deep branch of the arteria prin- 
ceps cervicis of the occipital and with branches which pass outward from the vertebral. 
1 See foot-note, p. 571. SURGICAL ANATOMY OF THE AXILLA. 
553 
Surgical Anatomy of the Axilla. 
The Axilla is a pyramidal space situated between the upper and lateral part of 
the chest and the inner side of the arm. [It should be studied in the living model 
in various postures of the arm. Its boundaries are best shown when the arm is 
abducted, and especially if the arm of the model be placed on the shoulder of the 
observer, and then pressed down.] 
Boundaries.-Its apex, which is directed upward toward the root of the neck* 
corresponds to the interval between the two Scaleni muscles on the first rib. The 
base, directed downward, is formed by the integument and a thick layer of fascia 
extending between the lower border of the Pectoralis major in front and the lower 
border of the Latissimus dorsi behind; it is broad internally at the chest, but nar- 
row and pointed externally at the arm. The anterior boundary is formed by the 
Pectoralis major and minor muscles, the former covering the whole of the anterior 
wall of the axilla, the latter covering only its central part. The posterior bound- 
ary, which extends somewhat lower than the anterior, is formed by the Subscapu- 
laris above, the Teres major and Latissimus dorsi below. On the inner side are 
the first four ribs with their corresponding Intercostal muscles and part of the Ser- 
ratus magnus. On the outer side, where the anterior and posterior boundaries con- 
verge, the space is narrow, and bounded by the humerus, the Coraco-brachialis, and 
Biceps muscles. 
Contents.-This space contains the axillary vessels and brachial plexus of 
nerves, with their branches, some branches of the intercostal nerves, and a large 
number of lymphatic glands, all connected together by a quantity of fat and loose 
areolar tissue. 
Their Position.-The axillary artery and vein, with the brachial plexus of 
nerves, extend obliquely along the outer boundary of the axillary space from its 
apex to its base, and are placed much nearer the anterior than the posterior wall 
[at the junction of the anterior and middle thirds], the vein lying to the inner or 
thoracic side of the artery and partially concealing it. At the fore part of the 
axillary space, in contact with the Pectoral muscles, are the thoracic branches of 
the axillary artery, and along the anterior margin of the axilla the long thoracic 
artery extends to the side of the chest. At the back part, in contact with the 
lower margin of the Subscapularis muscle, are the subscapular vessels and nerves; 
winding around the lower border of this muscle is the dorsalis scapulas artery and 
veins; and toward the outer extremity of the muscle the posterior circumflex ves- 
sels and the circumflex nerve are seen curving backward to the shoulder. 
Along the inner or thoracic side no vessel of any importance exists, the upper 
part of the space being crossed merely by a few small branches from the superior 
thoracic artery. There are some important nerves, however, in this situation-viz. 
the posterior thoracic or external respiratory nerve [of Bell], descending on the 
surface of the Serratus magnus, to which it is distributed; and, perforating the 
upper and anterior part of this wall, the intercosto-humeral nerve or nerves, pass- 
ing across the axilla to the inner side of the arm. 
The cavity of the axilla is filled by a quantity of loose areolar tissue, a large 
number of small arteries and veins, all of which are, however, of inconsiderable 
size, and numerous lymphatic glands; these are from ten to twelve in number, and 
situated chiefly on the thoracic side and lower and back part of this space. 
The student should attentively consider the relation of the vessels and nerves in 
the several parts of the axilla, for it not unfrequently happens that the surgeon is 
called upon to extirpate diseased glands or to remove a tumor from this situation. 
In performing such an operation it will be necessary to proceed with much caution 
in the direction of the outer wall and apex of the space, as here the axillary vessels 
will be in danger of being wounded. Toward the posterior wall it will be neces- 
sary to avoid the subscapular, dorsalis scapulae, and posterior circumflex vessels, and 
along the anterior wall the thoracic branches. It is only along the inner or thoracic 
■wall and in the centre of the axillary cavity that there are no vessels of any import- 554 
THE ARTERIES. 
ance-a fortunate circumstance, for it is in this situation more especially that tumors 
requiring removal are usually situated. 
The Axillary Artery, the continuation of the subclavian, commences at the 
lower border of the first rib and terminates at the lower border of the tendon of 
the Teres major muscle, where it takes the name of brachial. Its direction varies 
with the position of the limb : when the arm lies by the side of the chest, the ves- 
sel forms a gentle curve, the convexity being upward and outward; when it is 
directed at right angles with the trunk, the vessel is nearly straight; and when it 
is elevated still higher, the artery describes a curve, the concavity of which is 
directed upward. At its commencement the artery is very deeply situated, but 
near its termination is superficial, being covered only by the skin and fascia. The 
description of the relations of this vessel is facilitated by its division into three 
portions, the first portion being that above the Pectoralis minor, the second portion 
behind, and the third below, that muscle. 
The first portion of the axillary artery is in relation in front with the clavic- 
ular portion of the Pectoralis major, the costo-coracoid membrane, the Subclavius, 
the external anterior thoracic nerve, and the acromio-thoracic and cephalic veins; 
behind, with the first intercostal space, the corresponding Intercostal muscle, the 
first serration of the Serratus magnus, and the posterior thoracic nerve; on its outer 
side, with the brachial plexus, from which it is separated by a little cellular interval; 
on its inner or thoracic side, with the axillary vein. 
The Axillary Artery. 
Relations of the First Portion of the Axillary Artery. 
In Front. 
Pectoralis major. 
Costo-coracoid membrane. 
Subclavius. 
External anterior thoracic nerve. 
Acromio-thoracic and cephalic veins. 
Axillary 
Artery. 
First portion. 
Outer Side. 
Brachial plexus. 
Inner Side. 
Axillary vein. 
Behind. 
First intercostal space and intercostal muscle. 
First serration of Serratus magnus. 
Posterior thoracic nerve. 
The second portion of the axillary artery lies behind the Pectoralis minor. It 
is covered in front by the Pectoralis major and minor muscles; behind it is sep- 
arated from the Subscapularis by a cellular interval; on the inner side is the axil- 
lary vein. The brachial plexus of nerves surrounds the artery, and separates it 
from direct contact with the vein and adjacent muscles. 
Relations of the Second Portion of the Axillary Artery 
In Front. 
Pectoralis major and minor. 
Outer Side. 
Outer cord of plexus. 
Axillary 
Artery. 
Second 
portion. 
Inner Side. 
Axillary vein. 
Inner cord of plexus. 
Behind. 
Subscapularis. 
Posterior cord of plexus. THE AXILLARY ARTERY 
555 
The third portion of the axillary artery lies below the Pectoralis minor. It is 
in relation in front with the lower part of the Pectoralis major above, being cov- 
ered only by the integument and fascia below, where it is crossed by the inner head 
of the median nerve; behind, with the lower part of the Subscapularis and the ten- 
dons of the Latissimus dorsi and Teres major; on its outer side, with the Coraco- 
brachialis ; on its inner or thoracic side, with the axillary vein. The nerves of the 
brachial plexus bear the following relation to the artery in this part of its course: 
on the outer side are the median nerve and the musculo-cutaneous for a short dis- 
tance ; on the inner side, the ulnar, the internal, and lesser internal cutaneous 
nerves; and behind, the musculo-spiral and circumflex, the latter extending only 
to the lower border of the Subscapularis muscle. 
Relations of the Third Portion of the Axillary Artery. 
In Front. 
Integument and fascia. 
Pectoralis major. 
Inner head of median nerve, 
Outer Side. 
Coraco-brachialis. 
Median nerve. 
Musculo-cutaneous nerve, 
Inner Side. 
Ulnar nerve. 
Internal cutaneous nerves. 
Axillary veins. 
Axillary 
Artery. 
Third portion. 
Behind. 
Subscapularis. 
Tendons of Latissimus dorsi and Teres major. 
Musculo-spiral and circumflex nerves. 
Peculiarities.-The axillary artery, in about one case out of every ten, gives off a large 
branch, which forms either one of the arteries of the forearm or a large muscular trunk. In the 
first set of cases this artery is most frequently the radial (1 in 33), sometimes the ulnar (1 in 72), 
and very rarely the interosseous (1 in 506). In the second set of cases the trunk has been found 
to give origin to the subscapular, circumflex, and profunda arteries of the arm. Sometimes only 
one of the circumflex or one of the profunda arteries arose from the trunk. In these cases the 
brachial plexus surrounded the trunk of the branches, and not the main vessel. 
Surgical Anatomy.-The student, having carefully examined the relations of the axillary 
artery in its various parts, should now consider in what situation compression of this vessel may 
be most easily effected, and the best position for the application of a ligature to it when necessary. 
Compression of the vessel is required in the removal of tumors or in amputation of the 
upper part of the arm; and the only situation in which this can be effectually made is in the 
lower part of its course: by pressing on it in this situation from within outward against the 
humerus the circulation may be effectually arrested. 
The application of a ligature to the axillary artery may be required in cases of 
aneurism of the upper part of the brachial; and there are only two situations in which it can be 
secured-viz. in the first and in the third parts of its course-for the axillary artery at its central 
part is so deeply seated, and at the same time so closely surrounded with large nervous trunks 
that the application of a ligature to it in that situation would be almost impracticable. 
In the third part of its course the operation is most simple, and may be performed in the 
following manner: The patient being placed on a bed, and the arm separated from the side 
with the hand supinated, the head of the humerus is felt for, and an incision made through the 
integument over it about two inches in length, a little nearer to the anterior than the posterior 
fold of the axilla. After carefully dissecting through the areolar tissue and fascia, the median 
nerve and axillary vein are exposed: the former having been displaced to the outer and the lat- 
ter to the inner side of the arm, the elbow being at the same time bent, so as to relax the struc- 
tures and facilitate their separation, the ligature may be passed round the artery from the ulnar 
to the radial side. This portion of the artery is occasionally crossed by a muscular slip derived 
from the Latissimus dorsi, which may mislead the surgeon during an operation. The occasional 
existence of this muscular fasciculus was spoken of in the description of the muscles. It may 
easily be recognized by the transverse direction of its fibres. 
The first portion of the axillary artery may be tied in cases of aneurism encroaching so 
far upward that a ligature cannot be applied in the lower part of its course. Notwithstanding 
that this operation has been performed in some few cases, and with success, its performance is 
attended with much difficulty and danger. The student will remark that in this situation it 
would be necessary to divide a thick muscle, and, after separating the costo-coracoid membrane 
the artery would be exposed at the bottom of a more or less deep space, with the cephalic and 556 
TH Fa ARTERIES. 
axillary veins in such relation with it as must render the application of a ligature to this part of 
the vessel particularly hazardous. Under such circumstances it is an easier and, at the same 
time, more advisable operation to tie the subclavian artery in the third part of its course. 
In a case of wound of the vessel the general practice of cutting down upon and tying it above 
and below the wounded point should be adopted in all cases. 
Collateral Circulation after Ligature of the Axillary Artery.-If the artery be 
tied above the origin of the acromial thoracic, the collateral circulation will be carried on by the 
same branches as after the ligature of the subclavian; if at a lower point, between the acromial 
thoracic and subscapular arteries, the latter vessel, by its free anastomqses with the other scap- 
ular arteries, branches of the subclavian, will become the chief agent in carrying on the circula- 
tion, to which the long thoracic, if it be below the ligature, will materially contribute by its 
anastomoses with the intercostal and internal mammary arteries. If the point included in the 
ligature be below the origin of the subscapular artery, the anastomoses are less free. The chief 
agents in restoring the circulation will be the posterior circumflex by its anastomoses with the 
suprascapular and acromial thoracic and with the superior profunda, and- the communications 
between the subscapular and superior profunda, which will be afterward referred to as perform- 
ing the same office after ligature of the brachial. The cases in which the operation has been 
performed are few in number, and no published account of dissection of the collateral circulation 
appears to exist. 
The branches of the axillary artery are 
From 1st Part 
Superior Thoracic. 
Acromial Thoracic. 
Long Thoracic. 
Alar Thoracic. 
From 2d Part < 
' Subscapular. 
Anterior Circumflex. 
Posterior Circumflex. 
From 3d Part 
The superior thoracic is a small artery which arises from the axillary sep- 
arately, or by a common trunk with the acromial thoracic. Running forward and 
inward along the upper border of the Pectoralis minor, it passes between it and 
the Pectoralis major to the side of the chest. It supplies these muscles and the 
parietes of the thorax, anastomosing with the internal mammary and intercostal 
arteries. 
The acromial thoracic is a short trunk which arises from the fore part of the 
axillary artery. Projecting forward to the upper border of the Pectoralis minor, 
it divides into three sets of branches-thoracic, acromial, and descending. The 
thoracic branches, two or three in number, are distributed to the Serratus magnus 
and Pectoral muscles, anastomosing with the intercostal branches of the internal 
mammary. The acromial branches are directed outward toward the acromion, sup- 
plying the Deltoid muscle, and anastomosing on the surface of the acromion with 
the suprascapular and posterior circumflex arteries. The descending branch passes 
in the interspace between the Pectoralis major and Deltoid, accompanying the cepha- 
lic vein and supplying both muscles. 
The long1 thoracic passes downward and inward along the lower border of the 
Pectoralis minor to the side of the chest, supplying the Serratus magnus, the Pec- 
toral muscles, and the mammary gland, and sending branches across the axilla to 
the axillary glands and subscapularis, which anastomose with the internal mammary 
and intercostal arteries. 
The alar thoracic is a small branch which supplies the glands and areolar tissue 
of the axilla. Its place is frequently supplied by branches from some of the other 
thoracic arteries. 
The subscapular, the largest branch of the axillary artery, arises opposite the 
lower border of the Subscapularis muscle, and passes downward and backward 
along its lower margin to the inferior angle of the scapula, where it anastomoses 
with the posterior scapular, a branch of the transversalis colli from the thyroid axis 
of the subclavian. It distributes branches to the muscles in its neighborhood, and 
gives off, about an inch and a half from its origin, a large branch, the dorsalis 
scapulai [Fig. 387, p. 551], which curves round the inferior border of the scapula, 
leaving the axilla in the interspace between the Teres minor above, the Teres major THE AXILLARY ARTERY. 
557 
below, and the long head of the Triceps in front. Three branches or sets of 
branches arise from the dorsalis scapulae: the first enters the subscapular fossa 
beneath the Subscapularis, which it supplies, anastomosing with the posterior scap- 
ular and suprascapular arteries; the second, the trunk of the artery (dorsalis scap~ 
ulce), turns round the axillary border of the scapula and enters the infraspinous 
fossa, where it anastomoses with the suprascapular and posterior scapular arteries; 
and a third or median branch is continued along the axillary border of the scapula, 
between the Teres major and minor, and at the dorsal surface of the inferior angle 
of the bone anastomoses with the posterior scapular. 
The circumflex arteries wind round the neck of the humerus. The posterior 
circumflex (Fig. 387), the larger of the two, arises from the back part of the axillary 
Fig. 388. 
Art first or 
The Axillary Artery and its Branches. 
opposite the lower border of the Subscapularis muscle, and, passing backward with 
the circumflex veins and nerve through the quadrangular space bounded by the 
Teres major and minor, the scapular head of the Triceps, and the humerus, winds 
round the neck of that bone and is distributed to the Deltoid muscle and shoulder- 
joint, anastomosing with the anterior circumflex and acromial thoracic arteries and 
with the superior profunda branch of the brachial artery. The anterior circumflex 
(Figs. 387, 388), considerably smaller than the preceding, arises just below that 
vessel from the outer side of the axillary artery. It passes horizontally outward 
beneath the Coraco-brachialis and short head of the Biceps, lying upon the fore 
part of the neck of the humerus, and on reaching the bicipital groove gives off an 
ascending branch which passes upward along the groove to supply the head of the 
bone and the shoulder-joint. The trunk of the vessel is then continued outward 
beneath the Deltoid, which it supplies, and anastomoses with the posterior circum- 
flex and acromial thoracic arteries. 558 
THE ARTERIES. 
Brachial Artery (Fig. 389). 
The Brachial Artery commences at the lower margin of the tendon of the 
Teres major, and, passing down the inner and anterior aspect of the arm, termi- 
nates about half an inch below the 
bend of the elbow, where it divides 
into the radial and ulnar arteries. 
The direction of this vessel is mark- 
ed by a line drawn from the outer side 
of the axillary space between the folds 
of the axilla [better, from the junction 
of the anterior and middle thirds of the 
axilla] to a point midway between the 
condyles of the humerus which cor- 
responds to the depression along the 
inner border of the Coraco-brachialis 
and Biceps muscles. In the upper 
part of its course the artery lies inter- 
nal to the humerus, but below it is in 
front of that bone. [It very frequently 
presents a high bifurcation-a very im- 
portant fact. (See next page.)] 
Relations.-This artery is super- 
ficial throughout its entire extent, be- 
ing covered in front by the integument, 
the superficial and deep fascia; the bi- 
cipital fascia separates it opposite the 
elbow from the median basilic vein; 
the median nerve crosses it at its mid- 
dle. Behind, it is separated from the 
inner side of the humerus above by 
the Ions and inner heads of the Tri - 
ceps, the musculo-spiral nerve and su- 
perior profunda artery intervening, and 
from the front of the bone below by 
the insertion of the Coraco-brachialis 
muscle and by the Brachialis anticus. 
By its outer side it is in relation with 
the commencement of the median nerve 
and the Coraco-brachialis and Biceps 
muscles, which slightly overlap the ar- 
tery. By its inner side its upper half 
is in relation with the internal cutane- 
ous and ulnar nerves, its lower half 
with the median nerve. The basilic 
vein lies on the inner side of the ar- 
tery, but is separated from it in the 
lower part of the arm by the deep fascia. It is accompanied by two veme comites, 
which lie in close contact with the artery, being connected together at intervals by 
short transverse communicating branches. 
Fig. 389. 
IjLtiTTMl 
■ Cu.ta/neouaNervtt 
- Museu/lo - Spiral 
Nerve 
/ /Superior 
' Frofu-'ndd, 
I Inferior 
I Profunda 
- Anattomo tic a, 
Magna 
The Surgical Anatomy of the Brachial Artery. BRACHIAL ARTERY. 
559 
Plan of the Relations of the Brachial Artery. 
In Front. 
Integument and fasciae. 
Bicipital fascia, median basilic vein. 
Median nerve. 
Outer Side. 
Median nerve (above). 
Coraco-brachialis. 
Biceps. 
Inner Side. 
Internal cutaneous and ulnar nerve. 
Median nerve (below). 
Basilic vein. 
Brachial 
Artery. 
Behind. 
Triceps. 
Musculo-spiral nerve. 
Superior profunda artery. 
Coraco-brachialis. 
Brachialis anticus. 
Bend of the Elbow. 
At the bend of the elbow the brachial artery sinks deeply into a triangular inter- 
val, the base of which is directed upward toward the humerus, and the sides of which 
are bounded externally by the Supinator longus, internally by the Pronator radii 
teres; its floor is formed by the Brachialis anticus and Supinator brevis. This 
space contains the brachial artery with its accompanying veins, the radial and ulnar 
arteries, the median and musculo-spiral nerves, and the tendon of the Biceps. The 
brachial artery occupies the middle line of this space, and divides opposite the neck 
of the radius into the radial and ulnar arteries; it is covered in front by the integ- 
ument, the superficial fascia, and the median basilic vein, the vein being separated 
from direct contact with the artery by the bicipital fascia; behind, it lies on the Bra- 
chialis anticus, which separates it from the elbow-joint. The median nerve lies on 
the inner side of the artery, but separated from it below by an interval of half an 
inch and by the coronoid head of the Pronator radii teres. The tendon of the 
Biceps lies to the outer side of the space, and the musculo-spiral nerve still 
more externally lying upon the Supinator brevis and partly concealed by the 
Supinator longus. 
Peculiarities of the Artery as regards its Course.-The brachial artery, accom- 
panied by the median nerve, may leave the inner border of the Biceps and descend toward the 
inner condyle of the humerus, where it usually curves round a prominence of bone, to which it is 
connected by a fibrous band ; it then inclines outward, beneath or through the substance of the 
Pronator teres muscle, to the bend of the elbow. The variation bears considerable analogy with 
the normal condition of the artery in some of the Carnivora: it has been referred to above in the 
description of the humerus (p. 240). 
As regards its Division.-Occasionally the artery is divided for a short distance at its 
upper part into two trunks, which are united above and below. A similar peculiarity occurs in 
the main vessel of the lower limb. 
The point of bifurcation may be above or below the usual point, the former condition being 
by far the most frequent. Out of 481 examinations recorded by Mr. Quain, some made on the 
right, and some on the left side of the body, iff 386 the artery bifurcated in its normal position. 
In 1 case only was the place of division lower than usual, being two or three inches below the 
elbow-joint. "In 94 cases out of 481, or about 1 in 5|, there were two arteries instead of one in 
some part or in the whole of the arm." 
There appears, however, to be no correspondence between the arteries of the two arms with 
respect to their irregular division, for in 61 bodies it occurred on one side only in 43 ; on both 
sides in different positions in 13 ; on both sides in the same position in 5. 
The point of bifurcation takes place at different parts of the arm, being most frequent in the 
upper part, less so in the lower part, and least so in the middle, the most usual point for the 
application of a ligature; under any of these circumstances two large arteries would be found in 
the arm instead of one. The most frequent (in three out of four) of these peculiarities is the high 
division of the radial. That artery often arises from the inner side of the brachial and runs 
parallel with the main trunk to the elbow, where it crosses it, lying beneath the fascia; or it 
may perforate the fascia and pass over the artery immediately beneath the integument. 
The ulnar sometimes arises from the brachial high up, and then occasionally leaves that ves- 
sel at the lower part of the arm and descends toward the inner condyle. In the forearm it gen- 560 
THE ARTERIES. 
erally lies beneath the deep fascia, superficial to the Flexor muscles, occasionally between the 
integument and deep fascia, and very rarely beneath the Flexor muscles. 
The interosseous artery sometimes arises from the upper part of the brachial or axillary : as 
it passes down the arm it lies behind the main trunk, and at the bend of the elbow regains its 
usual position. 
In some cases of high division of the radial the remaining trunk (ulnar interosseous) occasion- 
ally passes, together with the median nerve, along the inner margin of the arm to the inner con- 
dyle, and then, passing from within outward, beneath or through the Pronator teres, regains its 
usual position at the bend of the elbow. 
Occasionally the two arteries representing the brachial are connected at the bend of the elbow 
by a short transverse branch, and are even sometimes reunited. 
Sometimes long slender vessels, vasa aberrantia, connect the brachial or axillary arteries with 
one of the arteries of the forearm or a branch from them. These vessels usually join the radial. 
Varieties in Muscular Relations.1-The brachial artery is occasionally concealed, in 
some part of its course, by muscular or tendinous slips derived from the Coraco-brachialis, Biceps, 
Brachialis anticus, and Pronator radii teres muscles. 
Surgical Anatomy.-Compression of the brachial artery is required in cases of amputa- 
tion and some other operations in the arm and forearm; and it will be observed that it may be 
effected in almost any part of the course of the artery. If pressure is made in the upper part of 
the limb, it should be directed from within outward; and if in the lower part, from before back- 
ward, as the artery lies on the inner side of the humerus above and in front of it below. The 
most favorable situation is near the insertion of the Coraco-brachialis. 
The application of a ligature to the brachial artery may be required in cases of wound of the 
vessel and in some cases of wound of the palmar arch. It is also sometimes necessary in cases 
of aneurism of the brachial, the radial, ulnar, or interosseous arteries. The artery may be 
secured in any part of its course. The chief guides in determining its position are the surface- 
markings produced by tne inner margin of the Coraco-brachialis and Biceps, the known course 
of the vessel, and its pulsation, which should be carefully felt for before any operation is per- 
formed, as the vessel occasionally deviates from its usual position in the arm. In whatever sit- 
uation the operation is performed, great care is necessary, on account of the extreme thinness of 
the parts covering the artery and the intimate connection which the vessel has throughout its 
whole course with important nerves and veins. Sometimes a thin layer of muscular fibre is met 
with concealing the artery; if such is the case, it must be cut across in order to expose the vessel. 
In the upper third of the arm the artery may be exposed in the following manner: 
The patient being placed horizontally upon a table, the affected limb should be raised from the 
side and the hand supinated. An incision about two inches in length should be made on the 
ulnar side of the Coraco-brachialis muscle, and the subjacent fascia cautiously divided, so as to 
avoid wounding the internal cutaneous nerve or basilic vein, which sometimes runs on the sur- 
face of the artery as high as the axilla. The fascia having been divided, it should be remembered 
that the ulnar and internal cutaneous nerves lie on the inner side of the artery, the median on 
the outer side, the latter nerve being occasionally superficial to the artery in this situation, and 
that the venae comites are also in relation with the vessel, one on either side. These being care- 
fully separated, the aneurism-needle should be passed round the artery from the ulnar to the 
radial side. 
If two arteries are present in the arm in consequence of a high division, they are usually 
placed side by side; and if they are exposed in an operation, the surgeon should endeavor to 
ascertain, by alternately pressing on each vessel, which of the two communicates with the wound 
or aneurism, when a ligature may be applied accordingly; or if pulsation or hemorrhage ceases 
only when both vessels are compressed, both vessels may be tied, as it may be concluded that 
the two communicate above the seat of disease or are reunited. 
It should also be remembered that two arteries may be present in the arm in a case of 
high division, and that one of these may be found along the inner intermuscular septum, in a 
line toward the inner condyle of the humerus or in the usual position of the brachial, but deeply 
placed beneath the common trunk: a knowledge of these facts will suggest the precautions 
necessary in every case and indicate the measures to be adopted when anomalies are met with. 
In the middle of the arm the brachial artery may be exposed by making an incision along 
the inner margin of the Biceps muscle. The forearm being bent so as to relax the muscle, it 
should be drawn slightly aside, and, the fascia being carefully divided, the median nerve will be 
exposed lying upon the artery (sometimes beneath) ; this being drawn inward and the muscle out- 
ward, the artery should be separated from its accompanying veins and secured. In this situation 
the inferior profunda may be mistaken for the main trunk, especially if enlarged, from the col- 
lateral circulation having become established; this may be avoided by directing the incision 
externally toward the Biceps, rather than inward or backward toward the Triceps. 
The lower part of the brachial artery is of extreme interest in a surgical point of 
view, on account of the relation which it bears to the veins most commonly opened in venesection. 
Of these vessels, the median basilic is the largest and most prominent, and consequently the one 
usually selected for the operation. It should be remembered that this vein runs parallel with 
the brachial artery, from which it is separated by the bicipital fascia, and that care should be 
taken in opening the vein not to carry the incision too deeply, so as to endanger the artery. 
1 See Struthers's Anatomical and Physiological Observations. BRACHIAL ARTERY. 
561 
Collateral Circulation.-After the application of a ligature to the brachial artery in the 
upper third of the arm, the circulation is carried on by branches from the circumflex and sub- 
scapular arteries, anastomosing with ascending branches from the superior profunda. If the 
brachial is tied beloiv the origin of the profunda arteries, the circulation is maintained by the 
branches of the profundse anastomosing with the recurrent radial, ulnar, and interosseous arte- 
ries. In two cases described by Mr. South,1 in which the brachial artery had been tied some time 
previously, in one "a long portion of the artery had been obliterated, and sets of vessels are 
descending on either side from above the obliteration, to be received into others, which ascend 
in a similar manner from below it. In the other the operation is less extensive, and a single 
curved artery about as big as a crow-quill passes from the upper to the lower open part of the 
artery." 
The branches of the brachial artery are the 
Superior Profunda. 
Nutrient Artery. 
Inferior Profunda. 
Anastomotica magna. 
Muscular. 
The superior profunda arises from the inner and back part of the brachial, 
just below the lower border of the Teres major, and passes backward to the inter- 
val between the outer and inner heads of the Triceps muscle, accompanied by the 
musculo-spiral nerve; it winds round the back part of the shaft of the humerus in 
the spiral groove between the Triceps and the bone, pierces the external intermus- 
cular septum, and descends to the space between the Brachialis anticus and Supina- 
tor longus, where it anastomoses with the recurrent branch of the radial artery. It 
supplies the Deltoid, Coraco-brachialis, and Triceps muscles. Near its commence- 
ment it sends off a branch which passes upward between the external and long 
heads of the Triceps muscle to anastomose with the posterior circumflex ; and 
whilst in the groove between the Triceps and the bone it gives off the posterior 
articular artery, which descends perpendicularly between the Triceps and the bone, 
accompanied by the nerve to the Anconeus muscle, to the back part of the elbow- 
joint, where it anastomoses with the interosseous recurrent branch, and on the inner 
side of the arm with the posterior ulnar recurrent and with the anastomotica magna 
and inferior profunda (Fig. 392). 
The nutrient artery of the shaft of the humerus arises from the brachial about 
the middle of the arm. Passing downward, it enters the nutrient canal of that bone 
near the insertion of the Coraco-brachialis muscle. 
The inferior profunda, of small size, arises from the brachial a little below the 
middle of the arm; piercing the internal intermuscular septum, it descends on the 
surface of the inner head of the Triceps muscle to the space between the inner con- 
dyle and olecranon, accompanied by the ulnar nerve, and terminates by anastomos- 
ing with the posterior ulnar recurrent and anastomotica magna. It also supplies a 
branch to the front of the internal condyle, which anastomoses with the anterior 
ulnar recurrent. 
The anastomotica magna arises from the brachial about two inches above the 
elbow-joint. It passes transversely inward upon the Brachialis anticus, and, piercing 
the internal intermuscular septum, winds round the back part of the humerus between 
the Triceps and the bone, forming an arch above the olecranon fossa by its junction 
with the posterior articular branch of the superior profunda. As this vessel lies 
on the Brachialis anticus, branches ascend to join the inferior profunda, and 
some descend in front of the inner condyle to anastomose with the anterior ulnar 
recurrent. Behind the internal condyle an offset is given off which anastomoses 
with the inferior profunda and posterior ulnar recurrent arteries and supplies the 
Triceps. 
The muscular are three or four large branches which are distributed to the 
muscles in the course of the artery. They supply the Coraco-brachialis, Biceps, 
and Brachialis anticus muscles. 
1 Chelius's Surgery, vol. ii. p. 254. See also White's engraving, referred to by Mr. South, of the 
anastomosing branches after ligature of the brachial, in White's Cases in Surgery. Porta also gives a 
case (with drawings) of the circulation after ligature of both brachial and radial (Alterazioni Pata- 
logiehe delle Arterie). 562 
THE ARTERIES. 
The Anastomosis around the Elbow-joint (Fig. 392, p. 568).-The vessels 
engaged in this anastomosis may be conveniently divided into those situated in front 
and behind the internal and external condyles. 'The branches anastomosing in front 
of the internal condyle are the anastomotica magna, the anterior ulnar recurrent, and 
the anterior terminal branch of the inferior profunda. Those behind the internal 
condyle are the anastomotica magna, the posterior ulnar recurrent, and the poste- 
rior terminal branch of the inferior profunda. The branches anastomosing in front 
of the external condyle are the radial recurrent and the termination of the superior 
profunda. Those behind the external condyle (perhaps more properly described as 
being situated between the external condyle and the olecranon) are the anastomotica 
magna, the interosseous recurrent, and the posterior articular branch of the superior 
profunda. There is also a large arch of anastomosis above the olecranon formed by 
the interosseous recurrent joining with the anastomotica magna and posterior ulnar 
recurrent (Fig. 392). 
From this description it will be observed that the anastomotica magna is the 
vessel most engaged, the only part of the anastomosis in which it is not employed 
being that in front of the external condyle. 
Radial Artery. 
The Radial Artery appears, from its direction, to be the continuation of the 
brachial, but in size it is smaller than the ulnar. It commences at the bifurcation 
of the brachia], just below the bend of the elbow, and passes along the radial side 
of the forearm to the wrist; it then winds backward, round the outer side of the 
carpus, beneath the extensor tendons of the thumb, and finally passes forward, 
between the two heads of the first Dorsal interosseous muscle, into the palm of the 
hand, where it crosses the metacarpal bones to the ulnar border of the hand to 
form the deep palmar arch. At its termination it inosculates with the deep 
branch of the ulnar artery. The relations of this vessel may thus be conve- 
niently divided into three parts - viz. in the forearm, at the back of the wrist, 
and in the hand. 
Relations.-In the forearm this vessel extends from opposite the neck of the 
radius to the fore part of the styloid process, being placed to the inner side of the 
shaft of the bone above, and in front of it below. It is superficial throughout its 
entire extent, being covered by the integument, the superficial and deep fasciae, 
and slightly overlapped above by the Supinator longus. In its course downward 
it lies upon the tendon of the Biceps, the Supinator brevis, the radial origin of 
the Flexor sublimis digitorum, the Pronator radii teres, the Flexor longus pollicis, 
the Pronator quadratus, and the lower extremity of the radius. In the upper third 
of its course it lies between the Supinator longus and the Pronator radii teres; in 
in its lower two-thirds, between the tendons of the Supinator longus and the Flexor 
carpi radialis. The radial nerve lies along the outer side of the artery in the mid- 
dle third of its course, and some filaments of the musculo-cutaneous nerve, after 
piercing the deep fascia, run along the lower part of the artery as it winds around 
the wrist. The vessel is accompanied by veme comites throughout its whole course. 
[An easy rule by which to remember the relations of the arteries and nerves of the 
forearm and leg is this : I he radial nerve lies to the radial side of the radial artery; 
the ulnar nerre lies to the ulnar side of the ulnar artery ; the tibial nerves (anterior 
and posterior) lie to -the fibular side of the tibial arteries-i. e. reverse the extrem- 
ity (if this expression be allowable), and the rule is reversed. In the lower part 
of the anterior tibial and the extreme upper part of the posterior tibial the rule is 
not reversed.j RADIAL ARTERY. 
563 
Plan of the Relations of the Radial Artery in the Forearm. 
In Front. 
Integument, superficial and deep fasciae. 
Supinator longus. 
Inner Side. 
Pronator radii teres. 
Flexor carpi radialis. 
Radial 
Artery in 
Forearm. 
Outer Side. 
Supinator longus. 
Radial nerve (middle third). 
Behind. 
Tendon of Biceps. 
Supinator brevis. 
Flexor sublimis digitorum. 
Pronator radii teres. 
Flexor longus pollicis. 
Pronator quadratus. 
Radius. 
At the wrist, as it winds around the outer side of the carpus from the styloid 
process to the first interosseous space, it lies upon the external lateral ligament, 
and then upon the scaphoid bone and trapezium, being covered by the extensor 
tendons of the thumb, subcutaneous veins, some filaments of the radial nerve, and 
the integument. It is accompanied by two veins and a filament of the musculo- 
cutaneous nerve. 
In the hand it passes from the upper end of the first interosseous space, between 
the heads of the Abductor indicis or first Dorsal interosseous muscle, transversely 
across the palm to the base of the metacarpal bone of the little finger, where it 
inosculates with the communicating branch from the ulnar artery, forming the deep 
palmar arch. It lies upon the carpal extremities of the metacarpal bones and the 
Interossei muscles, being covered by the flexor tendons of the fingers, the Lumbri- 
cales, the Opponens and Flexor brevis minimi digiti, and the Flexor brevis pollicis. 
Alongside of it is the deep branch of the ulnar nerve, but running in the opposite 
direction; that is to say, from within outward. 
Peculiarities.-The origin of the radial artery, according to Quinn, is, in nearly one case in 
eight, higher than usual, more frequently arising from the axillary or upper part of the brachial 
than from the lower part of this vessel. The variations in the position of this vessel in the arm 
and at the bend of the elbow have been already mentioned. In the forearm it deviates less fre- 
quently from its position than the ulnar. It has been found lying over the fascia, instead of 
beneath it. It has also been observed on the surface of the Supinator longus, instead of along 
its inner border: and in turning round the wrist it has been seen lying over instead of beneath 
the extensor tendons. 
Surgical Anatomy,-The operation of tying the radial artery is required in cases of 
wounds either of its trunk or in some of its branches or for aneurism ; and it will be observed 
that the vessel may be exposed in any part of its course through the forearm without the division 
of any muscular fibres. The operation in the middle or inferior third of the forearm is easily 
performed ; but in the upper third, near the elbow, it is attended with some difficulty, from the 
greater depth of the vessel and from its being overlapped by the Supinator longus muscle. 
To tie the artery in the upper third, an incision three inches in length should be made through 
the integument in a line drawn from the centre of the bend of the elbow to the front of the 
styloid process of the radius, avoiding the branches of the median vein ; the fascia of the arm 
being divided and the Supinator longus drawn a little outward, the artery will be exposed. The 
vena; comites should be carefully separated from the vessel and the ligature passed from the 
radial to the ulnar side. 
In the middle third of the forearm the artery may be exposed by making an incision of simi- 
lar length on the inner margin of the Supinator longus. In this situation the radial nerve lies 
in close relation with the outer side of the artery, and should, as well as the veins, be carefully 
avoided. 
In the lower third the artery is easily secured by dividing the integument and fascia in the 
interval between the tendons of the Supinator longus and Flexor carpi radialis muscles. 
The branches of the radial artery may be divided into three groups, correspond- 
ing with the three regions in which the vessel is situated: 564 
THE ARTERIES. 
"Radial Recurrent. 
Muscular. 
Superficialis volse. 
Anterior Carpal. 
Posterior Carpal. 
Metacarpal. 
Dorsales pollicis. 
Dorsalis indicis. 
In the 
Forearm. 
Wrist. 
Hand. 
Princeps pollicis. 
Radialis indicis. 
Perforating. 
Interosseous. 
The radial recurrent is given off immediately below the elbow. It ascends 
between the branches of the musculo-spiral nerve lying on the Supinator brevis, 
and then between the Supinator longus and Brachialis anticus, supplying these mus- 
cles and the elbow-joint and anastomosing with the terminal branches of the superior 
profunda. 
The muscular branches are distributed to the muscles on the radial side of the 
forearm. 
The superficialis volse arises from the radial artery just where this vessel is about 
to wind round the wrist. Running forward, it passes between the muscles of the 
thumb, which it supplies, and sometimes anastomoses with the termination of the 
ulnar artery, completing the superficial palmar arch. This vessel varies considerably 
in size; usually it is very small, and terminates in the muscles of the thumb ; some- 
times it is as large as the continuation of the radial. 
The carpal branches supply the joints of the wrist. The anterior carpal is a 
small vessel which arises from the radial artery near the lower border of the Prona- 
tor quadratus, and, running inward in front of the radius, anastomoses with the 
anterior carpal branch of the ulnar artery. From the arch thus formed branches 
descend to supply the articulations of the wrist. 
The posterior carpal is a small vessel which arises from the radial artery beneath 
the extensor tendons of the thumb ; crossing the carpus transversely to the inner 
border of the hand, it anastomoses with the posterior carpal branch of the ulnar, 
forming the posterior carpal arch. From this arch are given off descending branches 
-the dorsal interosseous arteries for the third and fourth interosseous space, which 
anastomose with the posterior perforating branches from the deep palmar arch, and 
ascending branches to anastomose with the termination of the anterior interosseous 
artery. 
The metacarpal (first dorsal interosseous branch) arises beneath the exten- 
sor tendons of the thumb, sometimes with the posterior carpal artery; running 
forward on the second dorsal interosseous muscle, it communicates behind with 
the corresponding perforating branch of the deep palmar arch, and in front inos- 
culates with the digital branch of the superficial palmar arch, and, dividing into 
two dorsal digital branches, supplies the adjoining sides of the index and middle 
fingers. 
The dorsales pollicis are two small vessels which run along the sides of the 
dorsal aspect of the thumb. They arise separately, or occasionally by a common 
trunk near the base of the first metacarpal bone. 
The dorsalis indicis, also a small branch, runs along the radial sides of the 
back of the index finger, sending a few branches to the Abductor indicis. 
The princeps pollicis arises from the radial just as it turns inward to the deep 
part of the hand; it descends between the Abductor indicis and Flexor brevis pol- 
licis, then between the Adductor and Flexor brevis pollicis, along the ulnar side 
of the metacarpal bone of the thumb, to the base of the first phalanx, where it 
divides into two branches, which run along the sides of the palmar aspect of the 
thumb and form an arch on the under surface of the last phalanx, from which 
branches are distributed to the integument and pulp of the thumb. 
The radialis indicis arises close to the preceding, descends between the Abduc- 
tor indicis and Adductor pollicis, and runs along the radial side of the index finger 
to its extremity, where it anastomoses with the collateral digital artery from the RADIAL ARTERY. 
565 
Fig. 390. 
superficial palmar arch. At the lower 
border of the Adductoi' pollicis this vessel 
anastomoses with the princeps pollicis and 
gives a communicating branch to the su- 
perficial palmar arch. 
The perforating arteries, three in num- 
ber, pass backward between the heads of 
Fig. 391. 
Radial Recurrent- 
. Anastomotica 
Magna 
Radial' 
Recurrent j 
Anterior Ulnar 
Recurrent 
tsterior Ulnar 
Recurrent 
Posterior 
Interosseous 
Muscular- 
-Muscular 
Superficialis Voice. 
'Deep branch of Ulnar 
Anterior Carpal ' 
Superficialis Volce- 
Anterior Carpal 
■Deep branch of Ulnar 
Surgical Anatomy of the Radial and Ulnar Arteries. 
Ulnar and Radial Arteries, deep view. 
the last three Dorsal interossei muscles to inosculate with the dorsal interosseous 
arteries. 
The palmar interosseous, three or four in number, are branches of the deep 566 
THE ARTERIES. 
palmar arch; they run forward upon the Interossei muscles and anastomose at the 
clefts of the fingers with the digital branches of the superficial arch. 
Ulnar Artery. 
The Ulnar Artery, the larger of the twTo subdivisions of the brachial, com- 
mences a little below the bend of the elbow, and crosses the inner side of the 
forearm obliquely inward to the commencement of its lower half; it then runs 
along its ulnar border to the wrist, crosses the annular ligament on the radial side 
of the pisiform bone, and passes across the palm of the hand, forming the super- 
ficial palmar arch, which sometimes terminates by inosculating with the super- 
ficialis volae, but more frequently by anastomosing with a branch of the radialis 
indicis. 
Relations in the Forearm.-In its upper half it is deeply seated, being cov- 
ered by all the superficial Flexor muscles, excepting the Flexor carpi ulnaris; it is 
crossed by the median nerve, which lies to its inner side for about an inch, and it 
lies upon the Brachialis anticus and Flexor profundus digitorum muscles. In the 
lotcer half of the forearm it lies upon the Flexor profundus, being covered by the 
integument, the superficial and deep fasciae, and is placed between the Flexor carpi 
ulnaris and Flexor sublimis digitorum muscles. It is accompanied by two venae 
comites: the ulnar nerve lies on its inner side for the lowTer two-thirds of its extent, 
and a small branch from the nerve descends on the lower part of the vessel to the 
palm of the hand. [See Rule, p. 562.] 
Plan of Relations of the Ulnar Artery in the Forearm. 
In Front. 
Superficial layer of flexor muscles. 
Median nerve. 
Superficial and deep fasciae. 
Upper half. 
Lower half. 
Inner Side. 
Flexor carpi ulnaris. 
Ulnar nerve (lower two-thirds). 
Ulnar 
Artery in 
Forearm. 
Outer Side. 
Flexor sublimis digitorum. 
Behind. 
Brachialis anticus. 
Flexor profundis digitorum. 
At the wrist (Fig. 390) the ulnar artery is covered by the integument and 
fascia, and lies upon the anterior annular ligament. On its inner side is the pisi- 
form bone. The ulnar nerve lies at the inner side and somewhat behind the 
artery. 
In the palm of the hand the continuation of the ulnar artery is called the 
superficial palmar arch; it passes outward, describing a curve with its convexity 
to the fingers, to the interspace between the ball of the thumb and the index fin- 
ger, where it occasionally anastomoses with the superficialis volae, more frequently 
with a branch from the radialis indicis, thus completing the arch. If the thumb 
be put at right angles to the hand, the position of the superficial palmar arch will 
be roughly indicated by a line drawn along the lower margin of the thumb across 
the palm of the hand: the deep palmar arch is situated about a finger's breadth 
nearer to the carpus. 
The superficial palmar arch is covered by the Palmaris brevis, the palmar fascia, 
and integument, and lies upon the annular ligament, the muscles of the little finger, 
the tendons of the superficial flexor, and the divisions of the median and ulnar 
nerves, the latter accompanying the artery a short part of its course. ULNAR ARTERY. 
567 
Relations of the Superficial Palmar Arch 
Behind. 
Annular ligament. 
Origin of muscles of little finger. 
Superficial flexor tendons. 
Divisions of median and ulnar 
nerves. 
In Front. 
Integument. 
Palmaris brevis. 
Palmar fascia. 
Ulnar 
Artery in 
Hand. 
Peculiarities.-The ulnar artery has been found to vary in its origin nearly in the proportion 
of one in thirteen cases, in one case arising lower than usual, about two or three inches below 
the elbow, and in all other cases much higher, the brachial being a more frequent source of origin 
than the axillary. 
Variations in the position of this vessel are more frequent than in the radial. When its 
origin is normal the course of the vessel is rarely changed. When it arises high up, it is almost 
invariably superficial to the Flexor muscles in the forearm, lying commonly beneath the fascia, 
more rarely between the fascia and integument. In a few cases its position was subcutaneous in 
the upper part of the forearm, subaponeurotic in the lower part. 
Surgical Anatomy.-The application of a ligature to this vessel is required in cases of 
wound of the artery or of its branches, or in consequence of aneurism. In the upper half of the 
forearm the artery is deeply seated beneath the superficial flexor muscles, and the application 
of a ligature in this situation is attended with some difficulty. • An incision is to be made in the 
course of a line drawn from the front of the internal condyle of the humerus to the outer side of 
the pisiform bone, so that the centre of the incision is three fingers' breadth below the internal 
condyle. The skin and superficial fascia having been divided and the deep fascia exposed, the 
white line which separates the Flexor carpi ulnaris from the other flexor muscles is to be sought 
for, and the fascia incised in this line. The Flexor carpi ulnaris is now to be carefully separated 
from the other muscles, when the ulnar nerve will be exposed and must be drawn aside. Some 
little distance below the nerve the artery will be found accompanied by its venae comites, and 
may be ligatured by passing the needle from within outward. In the middle and lower third of 
the forearm this vessel may be easily secured by making an incision on the radial side of the 
tendon of the Flexor carpi ulnaris: the deep fascia being divided, and the Flexor carpi ulnaris 
and its companion muscle, the Flexor sublimis, being separated from each other, the vessel will 
be exposed, accompanied by its venae comites, the ulnar nerve lying on its inner side. The veins 
being separated from the artery, the ligature should be passed from the ulnar to the radial side, 
taking care to avoid the ulnar nerve. 
The branches of the ulnar artery may be arranged in the following groups: 
'Anterior Ulnar Recurrent. 
Posterior Ulnar Recurrent. 
Interosseous 
Muscular. 
Forearm. 
Anterior Interosseous. 
Posterior Interosseous. 
Wrist. 
f Anterior Carpal. 
[ Posterior Carpal. 
Hand. 
Deep or Communicating Branch. 
Digital. 
The anterior ulnar recurrent (Fig- 391) arises immediately below the elbow- 
joint, passes upward and inward between the Brachialis anticus and Pronator radii 
teres, supplies those muscles, and in front of the inner condyle anastomoses with the 
anastomotica magna and inferior profunda. 
The posterior ulnar recurrent is much larger, and arises somewhat lower than 
the preceding. It passes backward and inward beneath the Flexor sublimis, and 
ascends behind the inner condyle of the humerus. In the interval between this 
process and the olecranon it lies beneath the Flexor carpi ulnaris, ascending 
between the heads of that muscle, beneath the ulnar nerve; it supplies the neigh- 
boring muscles and joint, and anastomoses with the inferior profunda, anastomotica 
magna, and interosseous recurrent arteries (Fig. 392). 
The interosseous artery (Fig. 391) is a short trunk, about an inch in length 
and of considerable size, which arises immediately below the tuberosity of the 
radius, and, passing backward to the upper border of the interosseous membrane, 
divides into two branches, the anterior and posterior interosseous. 568 
THE ARTERIES. 
The anterior interosseous passes down the forearm on the anterior surface of 
the interosseous membrane, to which it is connected by a thin aponeurotic arch. It 
is accompanied by the interosseous branch of the median nerve, and overlapped by 
the contiguous margins of the 
Flexor profundus digitorum and 
Flexor longus pollicis muscles, 
giving off in this situation mus- 
cular branches and the nutrient 
arteries of the radius and ulna. 
At the upper border of the Pro- 
nator quadratus a branch de- 
scends beneath the muscle to 
anastomose in front of the car- 
pus with branches from the an- 
terior carpal and deep palmar 
arch. The continuation of the 
artery passes behind the Prona- 
tor quadratus (Fig. 392), and, 
piercing the interosseous mem- 
brane, anastomoses with the pos- 
terior interosseous artery. It 
then descends to the back of the 
wrist to join the posterior carpal 
arch. The anterior interosseous 
gives off a long, slender branch 
which accompanies the median 
nerve and gives offsets to its 
substance. This, the median 
artery, is sometimes much en- 
larged. 
The posterior interosseous 
artery passes backward through 
the interval between the oblique 
ligament and the upper border 
of the interosseous membrane. 
It appears between the contigu- 
ous borders of the Supinator 
brevis and the Extensor ossis 
metacarpi pollicis, and runs 
down the back part of the fore- 
arm between the superficial and 
deep layer of muscles, to both 
of which it distributes branches. 
Descending to the back of the 
wrist, it anastomoses with the 
termination of the anterior inter- 
osseous and with the posterior 
carpal branches of the radial 
and ulnar arteries. This artery 
gives off near its origin the in- 
terosseous recurrent branch, a 
large vessel which ascends to the 
interval between the external 
condyle and olecranon on or 
through the fibres of the Supinator brevis, but beneath the Anconeus, anastomos- 
ing with a branch from the superior profunda and with the posterior ulnar recurrent 
and anastomotica magna. 
Fig. 392. 
-Descending Branch froio 
Sup erior Prof. end a/ 
Anastomotica 
Magna 
Doxte/rior 
Clnai'Jlecu went 
-Posterior Interosseous 
lTermination of 
nterior Interosseous 
Posterior Carpal, 
( Ulnar') 
-Posterior Carpal 
(Ba dial) 
Betdial. 
Dorsalis Follicle 
-Dorsalis hdids 
Arteries of the Back of the Forearm and Hand. THE DESCENDING AORTA. 
569 
The muscular branches are distributed to the muscles along the ulnar side of 
the forearm. 
The carpal branches are intended for the supply of the wrist-joint. 
The anterior carpal is a small vessel which crosses the front of the carpus 
beneath the tendons of the Flexor profundus, and inosculates with a corresponding 
branch of the radial artery. 
The posterior carpal arises immediately above the pisiform bone, and winds 
backward beneath the tendon of the Flexor carpi ulnaris; it passes across the 
dorsal surface of the carpus beneath the extensor tendons, anastomosing with a 
corresponding branch of the radial artery and forming the posterior carpal arch. 
Immediately after its origin it gives off a small branch which runs along the ulnar 
side of the metacarpal bone of the little finger, forming one of the metacarpal arte- 
ries, and supplies the ulnar side of the dorsal surface of the little finger. 
The deep or communicating1 branch (Fig. 391, p. 565) arises at the com- 
mencement of the palmar arch, and passes deeply inward between the Abductor 
minimi digiti and Flexor brevis minimi digiti near their origins; it anastomoses 
with the termination of the radial artery, completing the deep palmar arch. 
The digital branches (Fig. 390, p. 565), four in number, are given off from 
the convexity of the superficial palmar arch. They supply the ulnar side of the 
little finger and the adjoining sides of the little, ring, middle, and index fingers, 
the radial side of the index finger and thumb being supplied from the radial artery. 
The digital arteries at first lie superficial to the flexor tendons, but as they pass 
forward with the digital nerves to the clefts between the fingers, they lie between 
them, and are there joined by the interosseous branches from the deep palmar arch. 
The digital arteries on the sides of the fingers lie beneath the digital nerves, and 
about the middle of the last phalanx the two branches for each finger form an arch, 
from the convexity of which branches pass to supply the matrix of the nail. 
The Descending Aorta. 
The Descending Aorta is divided into two portions, the thoracic and abdom- 
inal, in correspondence with the two great cavities of the trunk in which it is situ- 
ated. 
The Thoracic Aorta commences at the lower border of the fifth dorsal vertebra, 
on the left side, and terminates at the aortic opening in the Diaphragm, in front of 
the last dorsal vertebra. At its commencement it is situated on the left side of the 
spine; it approaches the median line as it descends, and at its termination lies 
directly in front of the column. The direction of this vessel being influenced by 
the spine, upon which it rests, it describes a curve which is concave forward in the 
dorsal region. As the branches given off from it are small, the diminution in the 
size of the vessel is inconsiderable. It is contained in the back part of the poste- 
rior mediastinum, being in relation in front, from above downward, with the left 
pulmonary artery, the left bronchus, the pericardium, and the oesophagus; behind, 
with the vertebral column and the vena azygos minor; on the right side, with the 
vena azygos major and thoracic duct; on the left side, with the left pleura and 
lung. The oesophagus, with its accompanying nerves, lies on the right side of the 
aorta above, but at the lower part of the thorax it gets in front of the aorta, and 
close to the Diaphragm is situated to its left side. 570 
THE ARTERIES. 
Plan of the Relations of the Thoracic Aorta 
In Front. 
Left pulmonary artery. 
Left bronchus. 
Pericardium. 
(Esophagus. 
Right Side. 
(Esophagus (above). 
Vena azygos major. 
Thoracic duct. 
Left Side. 
Pleura. 
Left lung. 
(Esophagus (below). 
Thoracic 
Aorta. 
Behind. 
Vertebral column. 
Vena azygos minor. 
Surgical Anatomy.-The student should now consider the effects likely to be produced 
by aneurism of the thoracic aorta, a disease of common occurrence. When we consider the great 
depth of the vessel from the surface and the number of important structures which surround it 
on every side, it may easily be conceived what a variety of obscure symptoms may arise from 
disease of this part of the arterial system, and how they may be liable to be mistaken for those 
of other affections. Aneurism of the thoracic aorta most usually extends backward along the left 
side of the spine, producing absorption of the bodies of the vertebrae, with curvature of the spine, 
whilst the irritation or pressure on the cord will give rise to pain either in the chest, back, or 
loins, with radiating pain in the left upper intercostal spaces from pressure on the intercostal 
nerves j» at the same time, the tumor may project backward on each side of the spine, beneath the 
integument, as a pulsating swelling, simulating abscesses connected with diseased bone, or it 
may displace the oesophagus and compress the lung on one or the other side. If the tumor extend 
forward, it may press upon and displace the heart, giving rise to palpitation and other symptoms 
of disease of that organ ; or it may displace, or even compress, the oesophagus, causing pain and 
difficulty of swallowing, as in stricture of that tube, and ultimately even open into it by ulcera- 
tion, producing fatal hemorrhage. If the disease extends to the right side, it may press upon 
the thoracic duct, or it may burst into the pleural cavity or into the trachea or lung, and, lastly, 
it may open into the posterior mediastinum. 
The aorta is comparatively often found to be obliterated at a particular spot-viz. at the 
junction of the arch with the thoracic aorta, just below the ductus arteriosus. Whether this is 
the result of disease or of congenital malformation is immaterial to our present purpose ; it affords 
an interesting opportunity of observing the resources of the collateral circulation. The course 
of the anastomosing vessels by which the blood is brought from the upper to the lower part of 
the artery will be found well described in an account of two cases in the Pathological transac- 
tions, vols. viii. and x. In the former (p. 162), Mr. Sydney Jones thus sums up the detailed 
description of the anastomosing vessels: 11 The principal communications by which the circula- 
tion was carried on, were-Firstly, the internal mammary, anastomosing with the intercostal 
arteries, with the phrenic of the abdominal aorta by means of the musculo-phrenic and comes 
nervi phrenici, and largely with the deep epigastric. Secondly, the superior intercostal, anasto- 
mosing anteriorly by means of a large branch with the first aortic intercostal, and posteriorly 
with the posterior branch of the same artery. Thirdly, the inferior thyroid, by means of a branch 
about the size of an ordinary radial, formed a communication with the first aortic intercostal. 
Fourthly, the transversalis colli, by means of very large communications with the posterior 
branches of the intercostals. Fifthly, the branches (of the subclavian and axillary) going to the 
side of the chest were large, and anastomosed freely with the lateral branches of the intercostals." 
In the second case also (vol. x. p. 97), Mr. Wood describes the anastomoses in a somewhat sim- 
ilar manner, adding the remark, that " the blood which was brought into the aorta through the 
anastomoses of the intercostal arteries appeared to be expended principally in supplying the 
abdomen and pelvis, while the supply to the lower extremities had passed through the internal 
mammary and epigastric." 
Branches of the Thoracic Aorta. 
Pericardiac. 
Bronchial. 
(Esophageal. 
Posterior Mediastinal. 
The pericardiac are a few small vessels, irregular in their origin, distributed to 
the pericardium. 
The bronchial arteries are the nutrient vessels of the lungs, and vary in num- 
ber, size, and origin. That of the right side arises from the first aortic intercostal, 
Intercostal. THE ABDOMINAL AORTA. 
571 
or by a common trunk with the left bronchial, from the front of the thoracic aorta. 
Those of the left side, usually two in number, arise from the thoracic aorta, one a 
little lower than the other. Each vessel is directed to the back part of the corre- 
sponding bronchus, along which they run, dividing and subdividing upon the bron- 
chial tubes, supplying them, the cellular, tissue of the lungs, the bronchial glands, 
and the oesophagus. 
The oesophageal arteries, usually four or five in number, arise from the front of 
the aorta and pass obliquely downward to the oesophagus, forming a chain of anas- 
tomoses along that tube, anastomosing with the oesophageal branches of the inferior 
thyroid arteries above and with ascending branches from the phrenic and gastric 
arteries below. 
The posterior mediastinal arteries are numerous small vessels which supply the 
glands and loose areolar tissue in the mediastinum. 
The intercostal arteries arise from the back part of the aorta. They are 
usually ten in number on each side, the superior intercostal space (and occasionally 
the second one) being supplied by the superior intercostal, a branch of the subcla- 
vian. The right intercostals are longer than the left, on account of the position of 
the aorta on the left side of the spine ; they pass outward, across the bodies of the ver- 
tebrae, to the intercostal spaces, being covered by the pleura, the oesophagus, thoracic 
duct, sympathetic nerve, and the vena azygos major; the left passing beneath the 
superior intercostal vein, the vena azygos minor, and sympathetic. In the inter- 
costal spaces each artery divides into two branches-an anterior or proper inter- 
costal branch, and a posterior or dorsal branch.1 
The anterior branch passes outward, at first lying upon the External intercostal 
muscle, covered in front by the pleura and a thin fascia. It then passes between the 
two layers of Intercostal muscles, and, having ascended obliquely to the lower border 
of the rib above, divides near the angle of that bone into two branches: of these, 
the larger runs in the groove on the lower border of the rib above, the smaller 
branch along the upper border of the rib below; passing forward, they supply the 
Intercostal muscles and anastomose with the anterior intercostal branches of the 
internal mammary and with the thoracic branches of the axillary artery. The first 
aortic intercostal anastomoses with the superior intercostal, and the last three pass 
between the abdominal muscles, inosculating with the epigastric in front and with 
the lumbar arteries. Each intercostal artery is accompanied by a vein and nerve, 
the former being above and the latter below, except in the upper intercostal spaces, 
where the nerve is at first above the artery. The arteries are protected from pres- 
sure during the action of the Intercostal muscles by fibrous arches thrown across 
and attached by each extremity to the bone. 
The posterior or dorsal branch of each intercostal artery passes backward to 
the inner side of the anterior costo-transverse ligament, and divides into a spinal 
branch, which supplies the vertebrae, the spinal cord, and its membranes; and a 
muscular branch, which is distributed to the muscles and integument of the back. 
The Abdominal Aorta (Fig. 393). 
The Abdominal Aorta commences at the aortic opening of the Diaphragm, in 
front of the body of the last dorsal vertebra, and, descending a little to the left side 
of the vertebral column, terminates on the body of the fourth lumbar vertebra, com- 
monly a little to the left of the middle line,2 where it divides into the two common 
iliac arteries. It diminishes rapidly in size in consequence of the many large branches 
1 Mr. W. J. Walsham describes a small twig as being given off from each intercostal close to their 
origin. He states that they can be traced running between the neck of the rib and the transverse 
process of the corresponding vertebra; they anastomose with similar twigs given off from the inter- 
costal artery next below. In the first and second spaces similar anastomosing twigs are given off from 
the superior intercostal {Journal of Anatomy and Physiology, vol. xvi. part iii. p. 443). 
2 Sir Joseph Lister, having accurately examined 30 bodies in order to ascertain the exact point 
of termination of this vessel, found it "either absolutely or almost absolutely mesial in 15, while in 
13 it deviated more or less to the left, and in 2 was slightly to the right" (Syst. of Surg., edited by 
T. Holmes, 2d ed., vol. v. p. 652). 572 
THE ARTERIES. 
which it gives off'. As it lies upon the bodies of the vertebrae the curve which it 
describes is convex forward, the greatest convexity corresponding to the third lum- 
bar vertebra, which is a little above and to the left side of the umbilicus. 
Relations.-It is covered in front by the lesser omentum and stomach, behind 
Fig. 393. 
which are the branches of the coeliac axis and the solar plexus; below these, by the 
splenic vein, the pancreas, the left renal vein, the transverse portion of the duode- 
num, the mesentery, and aortic plexus. Behind it is separated from the lumbar ver- 
tebrae by the left lumbar veins, the receptaculum chyli, and thoracic duct. On the 
right side it is in relation with the inferior vena cava (the right crus of the Dia- 
phragm being interposed above), the vena azygos, thoracic duct, and right semi- 
lunar ganglion ; on the left side, with the sympathetic nerve and left semilunar 
ganglion. 
The Abdominal Aorta and its Branches. THE ABDOMINAL AORTA. 
573 
Plan of the Relations of the Abdominal Aorta. 
In Front. 
Lesser omentum and stomach. 
Branches of the coeliac axis and solar plexus 
Splenic vein. 
Pancreas. 
Left renal vein. 
Transverse duodenum. 
Mesentery. 
Aortic plexus. 
Right Side. 
Right crus of diaphragm. 
Inferior vena cava. 
Vena azygos. 
Thoracic duct. 
Right semilunar ganglion. 
Abdominal 
Aorta. 
Left Side. 
Sympathetic nerve. 
Left semilunar ganglion. 
Behind. 
Left lumbar veins. 
Receptaculum chyli. 
Thoracic duct. 
Vertebral column. 
Surgical Anatomy.-Aneurisms of the abdominal aorta near the coeliac axis communi- 
cate in nearly equal proportion with the anterior and posterior parts of the artery. 
When an aneurismal sac is connected with the back part of the abdominal aorta, it usually 
produces absorption of the bodies of the vertebrae, and forms a pulsating tumor that presents 
itself in the left hypochondriac or epigastric regions, accompanied by symptoms of disturbance 
in the alimentary canal. Pain is invariably present, and is usually of two kinds-a fixed and 
constant pain in the back, caused by the tumor pressing on or displacing the branches of the 
solar plexus and splanchnic nerves, and a sharp lancinating pain radiating along those branches 
of the lumbar nerves which are pressed on by the tumor; hence the pain in the loins, the testes, 
the hypogastrium, and in the lower limb (usually of the left side). This form of aneurism 
usually bursts into the peritoneal cavity or behind the peritoneum in the left hypochondriac 
region ; or it may form a large aneurismal sac extending down as low as Poupart's ligament, 
hemorrhage in these cases being generally very extensive, but slowly produced and not rapidly 
fatal. 
When an aneurismal sac is connected with the front of the aorta near the coeliac axis, it 
forms a pulsating tumor in the left hypochondriac or epigastric regions, usually attended with 
symptoms of disturbance of the alimentary canal, as sickness, dyspepsia, or constipation, and 
accompanied by pain, which is constant, but nearly always fixed in the loins, epigastrium, or 
some part of the abdomen, the radiating pain being rare, as the lumbar nerves are seldom 
implicated. This form of aneurism may burst into the peritoneal cavity or behind the perito- 
neum, between the layers of the mesentery, or more rarely into the duodenum ; it rarely extends 
backward, so as to affect the spine. 
The abdominal aorta has been tied several times, and although none of the patients perma- 
nently recovered, still, as one of them lived as long as ten days, the possibility of the re-estab- 
lishment of the circulation may be considered to be proved. In the lower animals this artery is 
often successfully tied. The vessel may be reached in several ways. In the original operation, 
performed by Sir A. Cooper, an incision was made in the linea alba, the peritoneum opened in 
front, the finger carried down amongst the intestines toward the spine, the peritoneum again 
opened behind by scratching through the mesentery, and the vessel thus reached. Or either of 
the operations described below for securing the common iliac artery may, by extending the dis- 
section a sufficent distance upward, be made use of to expose the aorta. The chief difficulty in 
the dead subject consists in isolating the artery, in consequence of its great depth; but in the 
living subject the embarrassment resulting from the proximity of the aneurismal tumor and the 
great probability of disease in the vessel itself add to the dangers and difficulties of this formid- 
able operation so greatly that it is very doubtful whether it ought ever to be performed. [For 
the most recent investigations and operations for the cure of aortic aneurism by the introduction 
of catgut or wire, and the use of electricity therewith, see Dr. Robert Abbe's paper in the Med- 
ical News, April 9, 1887.] 
The collateral circulation would be carried on by the anastomosis between the internal mam- 
mary and the epigastric, by the free communication between the superior and inferior mes- 
enteries if the ligature were placed above the latter vessel, or by the anastomosis between the 
inferior mesenteric and the internal pudic when (as is more common) the point of ligature is 
below the origin of the inferior mesenteric, and possibly by the anastomoses of the lumbar 
arteries with the branches of the internal iliac. 
The circulation through the abdominal aorta may be commanded in thin persons by firm 
pressure with the fingers. A tourniquet has been invented for this purpose which is of the 
greatest use in amputation at the hip-joint and some other operations. [See p. 584.] 574 
THE ARTERIES. 
Branches of the Abdominal Aorta. 
Phrenic. 
Coeliac Axis. 
Gastric. 
Hepatic. 
Splenic. 
Renal. 
Spermatic. 
Inferior Mesenteric. 
Lumbar. 
Sacra media. 
Superior Mesenteric. 
Suprarenal. 
The branches may be divided into two sets : 1, those supplying the viscera; 2, 
those distributed to the walls of the abdomen. 
Renal. 
Spermatic. 
Visceral Branches. 
Gastric. 
Hepatic. 
Splenic. 
Coeliac Axis. 
Parietal Branches. 
Phrenic. 
Lumbar. 
Sacra media. 
Superior Mesenteric. 
Inferior Mesenteric. 
Suprarenal. 
To expose this artery, raise the liver, draw down the stomach, and then tear through the 
layers of the lesser omentum. 
The Cceliac Axis is a short thick trunk, about half an inch in length, which 
arises from the aorta opposite the margin of the Diaphragm, and, passing nearly 
Cceliac Axis (Fig. 395). 
[Fig. 394. 
Gastric. 
Pyloric. 
Hepatic. 
Gastro-duodenalis. 
Vasa brevia. 
Splenic. 
Pancreatic. 
Gastro-epiploica dextra. 
Gastro-epiploica sinistra. 
Pancreatico-duodenalis superior. 
Pancreatico-duodenalis inferior. 
Diagram of the Branches of the Coeliac Axis: CA, coeliac axis; SM, superior mesenteric-W. W. K.J 
horizontally forward (in the erect posture), divides into three large branches-the 
gastric, hepatic, and splenic-occasionally giving off one of the phrenic arteries. 
Relations.-It is covered by the lesser omentum. On the right side it is in 
relation with the right semilunar ganglion and the lobus Spigelii; on the left side, 
with the left semilunar ganglion and cardiac end of the stomach. Below it rests 
upon the upper border of the pancreas. 
The Gastric Artery (coronaria ventriculi), the smallest of the three branches 
of the coeliac axis, passes upward and to the left side, to the cardiac orifice of the 
stomach, distributing branches to the oesophagus which anastomose with the aortic 
oesophageal arteries; others supply the cardiac end of the stomach, inosculating with 
branches of the splenic artery: it then passes from left to right along the lesser curv- 
ature of the stomach to the pylorus, lying in its course between the layers of the 
lesser omentum, and giving branches to both surfaces of the organ : at its termina- 
tion it anastomoses with the pyloric branch of the hepatic. 
The Hepatic Artery in the adult is intermediate in size between the gastric and 
splenic; in the foetus it is the largest of the three branches of the coeliac axis. It CCELIAC AXIS. 
575 
is first directed forward and to the right, to the upper margin of the pyloric orifice 
of the stomach, forming the lower boundary of the foramen of Winslow. It then 
passes upward between the layers of the lesser omentum and in front of the fora- 
men of Winslow to the transverse fissure of the liver, where it divides into two 
Fig. 395. 
Erole ]ia,*oe<l through. Eojr.a.jike.n Winsloiu 
The Cceliac Axis and its Branches, the liver having been raised and the lesser omentum removed. 
branches, right and left, which supply the corresponding lobes of that organ, accom- 
panying the ramifications of the vena portae and hepatic duct. The hepatic artery, 
in its course along the right border of the lesser omentum, is in relation with the 
ductus communis choledochus and portal veins, the duct lying to the right of the 
artery and the vena portae behind. 
Its branches are the 
Pyloric. 
Gastro-duodenalis. ■ 
Cystic. 
Gastro-epiploica dextra. 
Pancreatico-duodenalis superior. 
The pyloric branch arises from the hepatic above the pylorus, descends to the 
pyloric end of the stomach, and passes from right to left along its lesser curvature, 
supplying it With branches and inosculating with the gastric artery. 
The gastro-duodenalis (Fig- 396) is a short but large branch which descends 
behind the duodenum near the pylorus, and divides at the lower border of the 
stomach into two branches-the gastro-epiploica dextra and the pancreatico-duo- 576 
THE ARTERIES. 
denalis superior. Previous to its division it gives off two or three small inferior 
pyloric branches to the pyloric end of the stomach and pancreas. 
The g-astro-epiploica dextra runs from right to left along the greater curvature 
of the stomach, between the layers of the great omentum, anastomosing about the 
middle of the lower border of the stomach with the gastro-epiploica sinistra from 
the splenic artery. This vessel gives off numerous branches, some of which ascend 
to supply both surfaces of the stomach, whilst others descend to supply the great- 
omentum. 
The pancreatico-duodenalis superior descends between the contiguous margins 
of the duodenum and pancreas. It supplies both these organs, and anastomoses 
Fig. 396. 
The Coeliac Axis and its Branches, the stomach having been raised and the transverse mesocolon removed. 
with the inferior pancreatico-duodenal branch of the superior mesenteric artery, and 
with the pancreatic branches of the splenic. 
In ulceration of the duodenum, which frequently occurs in connection with 
severe burns, this artery may be involved, and death may occur from hemorrhage 
into the intestinal canal. 
The Cystic Artery (Fig. 395), usually a branch of the right hepatic, passes 
upward and forward along the neck of the gall-bladder, and divides into two 
branches, one of which ramifies on its free surface, the other between it and the 
substance of the liver. 
The Splenic Artery, in the adult, is the largest of the three branches of the 
coeliac axis, and is remarkable for the extreme tortuosity of its course. It passes 
horizontally to the left side along the upper border of the pancreas, accompanied SUPERIOR MESENTERIC ARTERY. 
577 
by the splenic vein, which lies below it, and on arriving near the spleen divides 
into branches, some of which enter the hilum of that organ to be distributed to its 
structure, whilst others are distributed to the great end of the stomach. 
Pancreaticae parvae. 
Pancreatica magna. 
Gastric (Vasa brevia). 
Gastro-epiploica sinistra. 
The pancreatic are numerous small branches derived from the splenic as it 
runs behind the upper border of the pancreas, supplying its middle and left parts. 
One of these, larger than the rest, is given off from the splenic near the left extrem- 
ity of the pancreas; it runs from left to right near the posterior surface of the 
gland, following the course of the pancreatic duct, and is called the pancreatica 
magna. These vessels anastomose with the pancreatic branches of the pancreatico- 
duodenal arteries, derived from the hepatic on the one hand and superior mesenteric 
on the other. 
The gastric (vasa brevia) consist of from five to seven small branches, which 
arise either from the termination of the splenic artery or from its terminal branches, 
and, passing from left to right between the layers of the gastro-splenic omentum, are 
distributed to the great curvature of the stomach, anastomosing with branches of the 
gastric and gastro-epiploica sinistra arteries. 
The gastro-epiploica sinistra, the largest branch of the splenic, runs from left 
to right along the great curvature of the stomach, between the layers of the great 
omentum, and anastomoses with the gastro-epiploica dextra. In its course it dis- 
tributes several branches to the stomach, which ascend upon both surfaces ; others 
descend to supply the omentum. 
Superior Mesenteric Artery (Fig. 397). 
In order to expose this vessel raise the great omentum and transverse colon, draw down the 
small intestines, and cut through the peritoneum where the transverse mesocolon and mesentery 
join: the artery will then be exposed just as it issues from beneath the lower border of the 
pancreas. 
The Superior Mesenteric Artery supplies the whole length of the small intes- 
tine, except the first part of the duodenum; it also supplies the caecum, ascending 
and transverse colon; it is a vessel of large size, arising from the fore part of the 
aorta about a quarter of an inch below the coeliac axis, being covered at its origin 
by the splenic vein and pancreas. It passes forward between the pancreas and 
transverse portion of the duodenum, crosses in front of this portion of the intes- 
tine, and descends between the layers of the mesentery to the right iliac fossa, where 
it terminates, considerably diminished in size. In its course it forms an arch, the 
convexity of which is directed forward and downward to the left side, the concavity 
backward and upward to the right. It is accompanied by the superior mesenteric 
vein and is surrounded by the superior mesenteric plexus of nerves. Its branches 
are the 
Inferior Pancreatico-duodenal. 
Vasa intestini tenuis. 
Ileo-colic. 
Colica dextra. 
Colica media. 
The inferior pancreatico-duodenal is given off from the superior mesenteric 
behind the pancreas, and is distributed to the head of the pancreas with the trans- 
verse and descending portions of the duodenum, anastomosing with the superior 
pancreatico-duodenal artery. 
The vasa intestini tenuis [z. e. vessels of the small intestine] arise from the 
convex side of the superior mesenteric artery. They are usually from twelve to 
fifteen in number, and are distributed to the jejunum and ileum. They run par- 
allel with one another between the layers of the mesentery, each vessel dividing 
into two branches, which unite with a similar branch on each side, forming a series 
of arches, the convexities of which are directed toward the intestine. From this 578 
THE ARTERIES. 
Fig. 397. 
The Superior Mesenteric Artery and its Branches. 
first set of arches branches arise, which again unite with similar branches from 
either side, and thus a second series of arches is formed; and from these latter a 
[Fig. 398. 
Colica media. 
Vesa intestini tenuis. 
Colica dextra. 
-Colica sinistra. 
Ileo-colic. Superior hemorrhoidal. Sigmoid. 
Diagram of the Mesenteric Arteries : SM, superior mesenteric artery; IM, inferior mesenteric artery.-W. W. K.] 
third and a fourth, or even a fifth, series of arches are constituted, diminishing in INFERIOR MESENTERIC ARTERY. 
579 
size the nearer they approach the intestine. From the terminal arches numerous 
small straight vessels arise which encircle the intestine, upon which they are dis- 
tributed, ramifying thickly between its coats. 
The ileo-colic artery is the lowest branch given off from the concavity of the 
superior mesenteric artery. It descends between the layers of the mesentery to the 
right iliac fossa, where it divides into two branches. Of these, the inferior one 
inosculates with the lowest branches of the vasa intestini tenuis, from the convex- 
ity of which branches proceed to supply the termination of the ileum, the caecum 
and appendix caeci, and the ileo-caecal valve. The superior division inosculates 
with the colica dextra and supplies the commencement of the colon. 
The colica dextra arises from about the middle of the concavity of the supe- 
rior mesenteric artery, and, passing beneath the peritoneum to the middle of the 
ascending colon, divides into two branches-a descending branch, which inosculates 
with the ileo-colic; and an ascending branch, which anastomoses with the colica 
media. These branches form arches, from the convexity of which vessels are dis- 
tributed to the ascending colon. The branches of this vessel are covered with 
peritoneum only on their anterior aspect. 
The colica media arises from the upper part of the concavity of the superior 
mesenteric, and, passing forward between the layers of the transverse mesocolon, 
divides into two branches, the one on the right side inosculating with the colica 
dextra, that on the left side with the colica sinistra, a branch of the inferior mes- 
enteric. From the arches formed by their inosculation branches are distributed to 
the transverse colon. The branches of this vessel lie between two layers of peri- 
toneum. 
Inferior Mesenteric Artery (Fig. 399). 
In order to expose this vessel draw the small intestines and mesentery over to the right side 
of the abdomen, raise the transverse colon toward the thorax, and divide the peritoneum cover- 
ing the left side of the aorta. 
The inferior mesenteric artery supplies the descending and sigmoid flexure of 
the colon and the greater part of the rectum. It is smaller than the superior mes- 
enteric, and arises from the left side of the aorta, between one and two inches above 
its division into the common iliacs. It passes downward to the left iliac fossa, and 
then descends between the layers of the mesorectum into the pelvis, under the 
name of the superior hemorrhoidal artery. It lies at first in close relation with 
the left side of the aorta, and then passes as the superior hemorrhoidal in front of 
the left common iliac artery. Its branches are the 
Colica sinistra. 
Sigmoid. 
Superior Hemorrhoidal. 
The colica sinistra passes behind the peritoneum, in front of the left kidney, 
to reach the descending colon, and divides into two branches-an ascending branch, 
which inosculates with the colica media, and a descending branch, which anastomoses 
with the sigmoid artery. From the arches formed by these inosculations branches 
are distributed to the descending colon. 
The sig-moid. artery runs obliquely downward across the Psoas muscle to the 
sigmoid flexure of the colon, and divides into branches which supply that part of 
the intestine, anastomosing above with the colica sinistra, and below with the supe- 
rior hemorrhoidal artery. This vessel is sometimes replaced by three or four small 
branches. 
The superior hemorrhoidal artery, the continuation of the inferior mesenteric, 
descends into the pelvis between the layers of the mesorectum, crossing in its course 
the ureter and left common iliac vessels. Opposite the middle of the sacrum it divides 
into two branches, which descend one on each side of the rectum, where they divide 
into several small branches, which are distributed between the mucous and muscular 
coats of that tube nearly as far as its lower end, anastomosing with each other, with 580 
THE ARTERIES. 
the middle hemorrhoidal arteries, branches of the internal iliac, and with the inferior 
hemorrhoidal branches of the internal pudic. 
The student should especially remark that the trunk of the vessel descends along 
the back part of the rectum as far as the middle of the sacrum before it divides ; this 
is about a finger's length, or four inches, from the anus. In disease of this tube the 
rectum should never be divided beyond this point in that direction, for fear of involv- 
ing this artery. 
The Suprarenal Arteries (Fig. 393, p. 572) are two small vessels which arise, 
one on each side of the aorta, opposite the superior mesenteric artery. They pass 
Fig. 399. 
obliquely upward and outward to the under surface of the suprarenal capsules, to 
which they are distributed, anastomosing with capsular branches from the phrenic 
and renal arteries. In the adult these arteries are of small size; in the foetus they 
are as large as the renal arteries. 
The Renal Arteries are two large trunks which arise from the sides of the 
aorta, immediately below the superior mesenteric artery. Each is directed out- 
ward, so as to form nearly a right angle with the aorta. The right is longer than 
the left, on account of the position of the aorta; it passes behind the inferior vena 
cava. The left is somewhat higher than the right. Previously to entering the 
kidney each artery divides into four or five branches, which are distributed to its 
substance. At the hilum these branches lie between the renal vein and ureter, the 
The Inferior Mesenteric and its Branches. INFERIOR MESENTERIC ARTERY. 
581 
vein being usually in front, the ureter behind. Each vessel gives off some small 
branches to the suprarenal capsules, the ureter, and the surrounding cellular mem- 
brane and muscles. 
The Spermatic Arteries are distributed to the testes in the male and to the 
ovaria in the female. They are two slender vessels, of considerable length, which 
arise from the front of the aorta a little below the renal arteries. Each artery 
passes obliquely outward and downward, behind the peritoneum, crossing the ureter 
and resting on the Psoas muscle, the right spermatic lying in front of the inferior 
vena cava, the left behind the sigmoid flexure of the colon. On reaching the mar- 
gin of the pelvis each vessel passes in front of the corresponding external iliac 
artery, and takes a different course in the two sexes. 
In the male it is directed outward to the internal abdominal ring, and accom- 
panies the other constituents of the spermatic cord along the spermatic canal to the 
testis, where it becomes tortuous and divides into several branches, two or three of 
which accompany the vas deferens and supply the epididymis, anastomosing with 
the artery of the vas deferens; others pierce the back part of the tunica albuginea 
and supply the substance of the testis. 
In the female the spermatic arteries (ovarian) are shorter than in the male, and 
do not pass out of the abdominal cavity. On arriving at the margins of the pelvis 
each artery passes inward, between the two laminae of the broad ligament of the 
uterus, to be distributed to the ovary. One or two small branches supply the Fal- 
lopian tube; another passes on to the side of the uterus and anastomoses with the 
uterine arteries. Other offsets are continued along the round ligament, through the 
inguinal canal, to the integument of the labium and groin. 
At an early period of foetal life, when the testes lie by the side of the spine 
below the kidneys, the spermatic arteries are short; but as these organs descend 
from the abdomen into the scrotum the arteries become gradually lengthened. 
The Phrenic Arteries are two small vessels which present much variety in their 
origin. They may arise separately from the front of the aorta, immediately above 
the coeliac axis, or by a common trunk, which may spring either from the aorta or 
from the coeliac axis. Sometimes one is derived from the aorta, and the other from 
one of the renal arteries. In only one out of thirty-six cases examined did these 
arteries arise as two separate vessels from the aorta. They diverge from one another 
across the crura of the Diaphragm, and then pass obliquely upward and outward 
upon its under surface. The left phrenic passes behind the oesophagus and runs 
forward on the left side of the oesophageal opening. The right phrenic passes 
behind the inferior vena cava, and ascends along the right side of the aperture 
for transmitting that vein. Near the back part of the central tendon each vessel 
divides into two branches. The internal branch runs forward to the front of the 
thorax, supplying the Diaphragm and anastomosing with its fellow of the opposite 
side and with the musculo-phrenic and comes nervi phrenici, branches of the inter- 
nal mammary. The external branch passes toward the side of the thorax and inos- 
culates with the intercostal arteries. The internal branch of the right phrenic gives 
off a few vessels to the inferior vena cava; and the left one, some branches to the 
oesophagus. Each vessel also sends capsular branches to the suprarenal capsule of 
its own side. The spleen on the left side and the liver on the right also receive a 
few branches from these vessels. 
The Lumbar Arteries are analogous to the intercostal. They are usually four 
in number on each side, and arise from the back part of the aorta, nearly at right 
angles with that vessel. They pass outward and backward, around the sides of the 
body of the lumbar vertebra, behind the sympathetic nerve and the Psoas magnus 
muscle, those on the right side being covered by the inferior vena cava, and the 
two upper ones on each side by the crura of the Diaphragm. In the interval 
between the transverse processes of the vertebras each artery divides into a dorsal 
and an abdominal branch. 
The dorsal branch gives off, immediately after its origin, a spinal branch, which 
enters the spinal canal; it then continues its course backward, between the trans- 582 
THE ARTERIES. 
verse processes, and is distributed to the muscles and integument of the back, anas- 
tomosing with the similar branches of the adjacent lumbar arteries and with the 
posterior branches of the intercostal arteries. 
The spinal branch, besides supplying offsets which run along the nerves to the 
dura mater and cauda equina, anastomosing with the other spinal arteries, divides 
into two branches, one of which ascends on the posterior surface of the body of the 
vertebra above, and the other descends on the posterior surface of the body of the 
vertebra below, both vessels anastomosing with similar branches from neighboring 
spinal arteries. The inosculations of these vessels on each side, throughout the 
whole length of the spine, form a series of arterial arches behind the bodies of the 
vertebrae which are connected with each other, and with a median longitudinal vessel 
extending along the middle of the posterior surface of the bodies of the vertebrae, 
by transverse branches. From these vessels offsets are distributed to the periosteum 
and bones. 
The abdominal branches pass outward, behind the Quadratus lumborum, the 
lowest branch occasionally in front of that muscle, and, being continued between 
the abdominal muscles, anastomose with branches of the epigastric and internal 
mammary in front, the intercostals above, and those of the ilio-lumbar and circum- 
flex iliac below. 
The Middle Sacral Artery is a small vessel, about the size of a crow-quill, 
which arises from the back part of the aorta, just at its bifurcation. It descends 
upon the last lumbar vertebra and along the middle line of the front of the sacrum 
to the upper part of the coccyx, where it anastomoses with the lateral sacral arteries, 
and terminates in a minute branch which runs down to the situation of the body 
presently to be described as "Luschka's gland." From it branches arise which 
run through the mesorectum to supply the posterior surface of the rectum. Other 
branches are given off on each side which anastomose with the lateral sacral arteries, 
and send off small offsets which enter the anterior sacral foramina. 
Coccygeal Gland, or Luschka's Gland.-Lying near the tip of the coccyx, 
in a small tendinous interval formed by the union of the Levator ani muscles of 
either side, and just above the coccygeal attachment of the Sphincter ani, is a 
small conglobate body about as large as a lentil or a pea, first described by 
Luschka1 and named by him the coccygeal gland, but the real nature and uses 
of which are doubtful, nor does it seem at present certain that it always exists. Its 
most obvious connections are with the arteries of the part. It consists of a conge- 
ries of small arteries derived from the middle sacral and freely communicating with 
each other. These vessels are enclosed in one or more layers of polyhedral granular 
cells, and the whole structure is invested in a capsule of connective tissue which 
sends in trabeculae dividing the interior into a number of spaces in which the ves- 
sels and cells are contained. Nerves pass into this little body from the sympathetic, 
but their mode of termination is unknown. 
Common Iliac Arteries [Fig. 393, p. 572]. 
The abdominal aorta divides into the two Common Iliac Arteries. The bifur- 
cation usually takes place on the left side of the body of the fourth lumbar vertebra. 
This point corresponds to the left side of the umbilicus, and is on a level with a line 
drawn from the highest point of one iliac crest to the other. The common iliac arte- 
ries are about two inches in length; diverging from the termination of the aorta, they 
pass downward and outward to the margin of the pelvis, and divide opposite the 
intervertebral substance, between the last lumbar vertebra and the sacrum, into two 
branches-the external and internal iliac arteries, the former supplying the lower 
extremity, the latter the viscera and parietes of the pelvis. 
The right common iliac is somewhat larger than the left, and passes more 
obliquely across the body of the last lumbar vertebra. In front of it are the peri- 
1 Dec Hirnanhang und die Steissdruse des Berlin, 1860; Anatomie des Menschen, Tubingen, 
1864, vol. ii. pt. 2, p. 187. COMMON ILIAC ARTERIES. 
583 
toneum, the ileum, branches of the sympathetic nerve, and, at its point of division, 
the ureter. Behind it is separated from the last lumbar vertebra by the two com- 
mon iliac veins. On its outer side it is in relation with the inferior vena cava and 
the right common iliac vein above, and the Psoas magnus muscle below. 
The left common iliac is in relation in front with the peritoneum, branches of 
the sympathetic nerve, and the superior hemorrhoidal artery, and is crossed at its 
point of bifurcation by the ureter. The left common iliac vein lies partly on the 
inner side and partly beneath the artery; on its outer side the artery is in relation 
with the Psoas magnus. 
Branches.-The common iliac arteries give off small branches to the perito- 
neum, Psoas magnus, ureters, and the surrounding cellular tissue, and occasionally 
give origin to the ilio-lumbar or renal arteries. 
Plan of the Relations of the Common Iliac Arteries 
In Front. 
Peritoneum. 
Small intestines. 
Sympathetic nerves. 
Ureter. 
In Front. 
Peritoneum. 
Sympathetic nerves. 
Superior hemorrhoidal artery. 
Ureter. 
Outer Side.. 
Vena cava. 
Right common iliac 
vein. 
Psoas muscle. 
Inner Side. 
Left common iliac 
vein. 
Outer Side. 
Psoas muscle. 
Right 
Common 
Iliac. 
Left 
Common 
Iliac. 
Behind. 
Right and left common iliac veins. 
Behind. 
Left common iliac vein 
Peculiarities.-The point of origin varies according to the bifurcation of the aorta. In 
three-fourths of a large number of cases the aorta bifurcated either upon the fourth lumbar 
vertebra or upon the intervertebral disk between it and the fifth, the bifurcation being in one 
case out of nine below, and in one out of eleven above, this point. In ten out of every thirteen 
cases the vessel bifurcated within half an inch above or below the level of the crest of the ilium ; 
more frequently below than above. 
The point of division is subject to great variety. In two-thirds of a large number of cases 
it was between the last lumbar vertebra and the upper border of the sacrum, being above that 
point in one case out of eight, and below it in one case out of six. The left common iliac artery 
divides lower down more frequently than the right. 
The relative length also of the two common iliac arteries varies. The right common 
iliac was the longer in 63 cases; the left, in 52; whilst they were both equal in 53. The 
length of the arteries varied, in five-sevenths of the cases examined, from an inch and a half to 
three inches; in about half of the remaining cases the artery was longer, and in the other half, 
shorter, the minimum length being less than half an inch, the maximum four and a half inches. 
In one instance the right common iliac was found wanting, the external and internal iliacs aris- 
ing directly from the aorta. 
Surgical Anatomy.-The application of a ligature to the common iliac artery may be 
required on account of aneurism or hemorrhage implicating the external or internal iliacs, or on 
account of secondary hemorrhage after amputation of the thigh high up. It has been seen that 
the origin of this vessel corresponds to the left side of the umbilicus on a level with a line drawn 
from the highest point of one iliac crest to the opposite one, and its course to a line extending 
from the left side of the umbilicus downward toward the middle of Poupart's ligament. The 
line of incision required in the first steps of an operation for securing this vessel would materially 
depend upon the nature of the disease. If the surgeon select the iliac region, a curved incision 
about five inches in length may be made, commencing on the left side of the umbilicus, carried 
outward toward the anterior superior iliac spine, and then along the upper border of Poupart's 
ligament as far as its middle. But if the aneurismal tumor should extend high up in the abdo- 
men along the external iliac, it is better to select the side of the abdomen, approaching the artery 
from above by making an incision from four to five inches in length from about two inches above 
and to the left of the umbilicus, carried outward in a curved direction toward the lumbar region, 
and terminating a little below the anterior superior iliac spine. The abdominal muscles (in either 
case) having been cautiously divided in succession, the transversalis fascia must be carefully cut 
through, and the peritoneum, together with the ureter, separated from the artery and pushed 
aside; the sacro-iliac articulation must then be felt for, and upon it the vessel will be felt pul- 
sating, and may be fully exposed in close connection with its accompanying vein. On the right 
side both common iliac veins, as well as the inferior vena cava, are in close connection with the 584 
THE ARTERIES. 
artery, and must be carefully avoided. On the left side the vein usually lies on the inner side 
and behind the artery, but it occasionally happens that the two common iliac veins are joined on 
the left instead of the right side, which would add much to the difficulty of an operation in such 
a case. The common iliac artery may be so short that danger may be apprehended from second- 
ary hemorrhage if a ligature is applied to it. It would be preferable in such a case to tie both 
the external and internal iliacs near their origin. 
[Davy of England has devised a "rectal lever," which is introduced into the rectum and 
placed over the common iliac of the side to be operated on. By its elevation the artery can be 
compressed to prevent hemorrhage in hip-joint amputation. Lloyd of Birmingham has devised 
another excellent method to attain the same end, by compression of the external iliac and the 
branches of the internal iliac going to the thigh, by passing an elastic bandage around half of 
the pelvis above the iliac crest in front and between the anus and tuber ischii behind. A roller 
bandage should be placed over the external iliac.] 
Collateral Circulation.-The principal agents in carrying on the collateral circulation 
after the application of a ligature to the common iliac are the anastomoses of the hemorrhoidal 
branches of the internal iliac with the superior hemorrhoidal from the inferior mesenteric; the 
anastomoses of the uterine and ovarian arteries and of the vesical arteries of opposite sides ; 
of the lateral sacral with the middle sacral artery • of the epigastric with the internal mammary, 
inferior intercostal, and lumbar arteries • of the circumflex iliac with the lumbar arteries ; of the 
ilio-lumbar with the last lumbar artery; of the obturator artery, by means of its pubic branch, 
with the vessel of the opposite side and with the internal epigastric; and of the gluteal with the 
posterior branches of the sacral arteries. 
Internal Iliac Artery (Fig. 400). 
The Internal Iliac Artery supplies the walls and viscera of the pelvis, the gene- 
rative organs, and the inner side of the thigh. It is a short, thick vessel-smaller 
in the adult than the external iliac, and about an inch and a half in length-which 
arises at the point of bifurcation of the common iliac, and, passing downward to 
the upper margin of the great sacro-sciatic foramen, divides into twTo large trunks, 
an anterior and a posterior; a partially obliterated cord, the hypogastric artery, 
extending from the extremity of the vessel forward to the bladder. 
Relations.-In front with the ureter, which separates it from the peritoneum ; 
behind, with the internal iliac vein, the lumbo-sacral nerve, and Pyriformis muscle; 
by its outer side near its origin, with the Psoas magnus muscle. 
Plan of the Relations of the Internal Iliac Artery. 
In Front. 
Peritoneum. 
Ureter. 
Outer Side. 
Psoas magnus. 
Internal 
Iliac. 
Behind. 
Internal iliac vein. 
Lumbo-sacral nerve. 
Pyriformis muscle. 
In the foetus the internal iliac artery (Jiypogastric) is twice as large as the exter- 
nal iliac, and appears to be the continuation of the common iliac. Passing forward 
to the bladder, it ascends along the sides of that viscus to its summit, to 'which it 
gives branches; it then passes upward along the back part of the anterior wall of 
the abdomen to the umbilicus, converging toward its fellow of the opposite side. 
Having passed through the umbilical opening, the two arteries twine round the 
umbilical vein, forming with it the umbilical cord, and ultimately ramify in the 
placenta. The portion of the vessel within the abdomen is called the hypogastric 
artery, and that external to that cavity the umbilical artery. 
At birth, when the placental circulation ceases, the upper portion of the hypo- 
gastric artery, extending from the summit of the bladder upward to the umbilicus, INTERNAL ILIAC ARTERY. 
585 
contracts, and ultimately dwindles to a solid fibrous cord; but the lower portion, 
extending from its origin (in what is now the internal iliac artery) for about an 
Fig. 400. 
Ilio-Lumbar 
-QLuteaJ 
Arteries of the Pelvis. 
inch and a half to the wall of the bladder, and thence to the summit of that organ, 
is not totally impervious, though it becomes considerably reduced in size, and serves 
to convey blood to the bladder under the name of the superior vesical artery. 
Peculiarities as regards Length.-In two-thirds of a large number of cases the length 
of the internal iliac varied between an inch and an inch and a half; in the remaining third it 
was more frequently longer than shorter, the maximum length being three inches, the min- 
imum half an inch. 
The lengths of the common and internal iliac arteries bear an inverse proportion to each 
other, the internal iliac artery being long when the common iliac is short, and vice versa. 
As regards its Place of Division.-The place of division of the internal iliac varies 
between the upper margin of the sacrum and the upper border of the sacro-sciatic foramen. 
The arteries of the two sides in a series of cases often differed in length, but neither seemed 
constantly to exceed the other. 
Surgical Anatomy.-The application of a ligature to the internal iliac artery may be 
required in cases of aneurism or hemorrhage affecting one of its branches. The vessel may be 
secured by making an incision through the abdominal parietes in the iliac region, in a direction 
and to an extent similar to that for securing the common iliac: the transversalis fascia having 
been cautiously divided, and the peritoneum pushed inward from the iliac fossa toward the pel- 
vis, the finger may feel the pulsation of the external iliac at the bottom of the wound, and by 
tracing this vessel upward the internal iliac is arrived at, opposite the sacro-iliac articulation. It 586 
THE ARTERIES. 
should be remembered that the vein lies behind and on the right side, a little external to the 
artery and in close contact with it; the ureter and peritoneum, which lie in front, must also be 
avoided. The degree of facility in applying a ligature to this vessel will mainly depend upon 
its length. It has been seen that in the great majority of the cases examined the artery was 
short, varying from an inch to an inch and a half; in these cases the artery is deeply seated in 
the pelvis: when, on the contrary, the vessel is longer, it is found partly above that cavity. If 
the artery is very short, as occasionally happens, it would be preferable to apply a ligature to 
the common iliac or upon the external and internal iliacs at their origin. 
Collateral Circulation.-In Prof. Owen's dissection of a case in which the internal iliac 
artery had been tied by Stevens ten years before death for aneurism of the sciatic artery, the 
internal iliac was found impervious for about an inch above the point where the ligature had 
been applied; but the obliteration did not extend to the origin of the external iliac, as the ilio- 
lumbar artery arose just above this point. Below the point of obliteration the artery resumed 
its natural diameter, and continued so for half an inch, the obturator, lateral sacral, and gluteal 
arising in succession from the latter portion. The obturator artery was entirely obliterated. 
The lateral sacral artery was as large as a crow's quill, and had a very free anastomosis with 
the artery of the opposite side and with the middle sacral artery. The sciatic artery was entirely 
obliterated as far as its point of connection with the aneurismal tumor, but on the distal side of 
the sac it was continued down along the back of the thigh nearly as large in size as the femoral, 
being pervious about an inch below the sac by receiving an anastomosing vessel from the pro- 
funda.1 The circulation was carried on by the anastomoses of the uterine and ovarian arteries; 
of the opposite vesical arteries; of the hemorrhoidal branches of the internal iliac with those 
from the inferior mesenteric; of the obturator artery, by means of its pubic branch, with the 
vessel of the opposite side and with the epigastric and internal circumflex; of the circumflex 
and perforating branches of the profunda femoral with the sciatic ; of the gluteal with the pos- 
terior branches of the sacral arteries ; of the ilio-lumbar with the last lumbar ; of the lateral sac- 
ral with the middle sacral; and of the circumflex iliac with the ilio-lumbar and gluteal. 
From the Anterior Trunk. 
Superior Vesical. 
Middle Vesical. 
Inferior Vesical. 
Middle Hemorrhoidal. 
Obturator. 
Internal Pudic. 
Sciatic. 
Branches of the Internal Iliac. 
From the Posterior Trunk. 
Ilio-lumbar. 
Lateral Sacral. 
Gluteal. 
In female. 
Uterine. 
Vaginal. 
The superior vesical is that part of the foetal hypogastric artery which remains 
pervious after birth. It extends to the side of the bladder, distributing numerous 
branches to the apex and body of the organ. From one of these a slender vessel 
is derived which accompanies the vas deferens in its course to the testis, where it 
anastomoses with the spermatic artery. This is the artery of the vas deferens. 
Other branches supply the ureter. 
The middle vesical, usually a branch of the superior, is distributed to the base 
of the bladder and the under surface of the vesiculae seminales. 
The inferior vesical arises from the anterior division of the internal iliac, fre- 
quently in common with the middle hemorrhoidal, and is distributed to the base of 
the bladder, the prostate gland, and vesiculae seminales. The branches distributed 
to the prostate communicate with the corresponding vessel of the opposite side. 
The middle hemorrhoidal artery usually arises together with the preceding 
vessel. It supplies the rectum, anastomosing with the other hemorrhoidal arteries. 
The uterine artery passes downward from the anterior trunk of the internal 
iliac to the neck of the uterus. Ascending in a tortuous course on the side of this 
viscus between the layers of the broad ligament, it distributes branches to its sub- 
stance, anastomosing near its termination with a branch from the ovarian artery. 
Branches from this vessel are also distributed to the bladder and ureter. 
The vaginal artery is analogous to the inferior vesical in the male; it descends 
1 Medico-Chirurgical Trans., vol. xvi. INTERNAL ILIAC ARTERY. 
587 
upon the vagina, supplying its mucous membrane and sending branches to the neck 
of the bladder and contiguous part of the rectum. 
The obturator artery [Fig. 400] usually arises from the anterior trunk of the 
internal iliac, frequently from the posterior. It passes forward below the brim 
of the pelvis to the canal in the upper border of the obturator foramen, and, 
escaping from the pelvic cavity through this aperture, divides into an internal and 
an external branch. In the pelvic cavity this vessel lies upon the pelvic fascia, 
beneath the peritoneum and a little below the obturator nerve, and whilst passing 
through the obturator foramen is contained in an oblique canal formed by the hori- 
zontal branch of the pubes above and the arched border of the obturator mem- 
brane below. 
Branches.- Within the pelvis the obturator artery gives off an iliac branch to 
the iliac fossa, which supplies the bone and the Iliacus muscle, and anastomoses 
with the ilio-lumbar artery; a vesical branch, which runs backward to supply the 
bladder; and a pubic branch, which is given off from the vessel just before it 
leaves the pelvic cavity. This branch ascends upon the back of the pubes, com- 
municating with offsets from the epigastric artery and with the corresponding vessel 
of the opposite side. This branch is placed on the inner side of the femoral ring. 
External to the pelvis the obturator artery divides into an external and an internal 
branch, which are deeply situated beneath the Obturator externus muscle; skirting 
the circumference of the obturator foramen, they anastomose at the lower part of 
this aperture with each other and with branches of the internal circumflex artery. 
The internal branch curves downward along the inner margin of the obturator 
foramen, distributing branches to the Obturator externus muscle, Pectineus, Abduc- 
tors, and Gracilis, and anastomoses with the external branch and with the internal 
circumflex artery. 
The external branch curves round the outer margin of the foramen to the space 
between the Gemellus inferior and Quadratus femoris, where it anastomoses with the 
sciatic artery. It supplies the Obturator muscles, anastomoses, as it passes backward, 
with the internal branch and with the internal circumflex, and sends a branch to the 
hip-joint through the cotyloid notch, which ramifies on the round ligament as far as 
the head of the femur. 
Peculiarities.-In two out of every three cases the obturator arises from the internal iliac; 
in one case in three and a half from the epigastric; and in about one in seventy-two cases by 
two roots from both vessels. It arises in about the same proportion from the external iliac 
artery. The origin of the obturator from the epigastric is not commonly found on both sides of 
the same body. 
When the obturator artery arises at the front of the pelvis from the epigastric, it descends 
almost vertically to the upper part of the obturator foramen. The artery in this course usually 
lies in contact with the external iliac vein and on the outer side of the femoral ring (Fig. 401, a) : 
in such cases it would not be endangered in the operation for femoral hernia. Occasionally, 
however, it curves inward along the free margin of Gimbernat's ligament (Fig. 401, b), and 
Fig. 401. 
Variations in Origin and Course of Obturator Artery 
under such circumstances would almost completely encircle the neck of a hernial sac (supposing 
a hernia to exist in such a case), and would be in great danger of being wounded if an ope- 
ration was performed. THE ARTERIES. 
588 
The internal pudic is the smaller of the two terminal branches of the anterior 
trunk of the internal iliac, and supplies the external organs of generation. It 
passes downward and outward to the lower border of the great sacro-sciatic fora- 
men, and emerges from the pelvis between the Pyriformis and Coccygeus muscles; 
it then crosses the spine of the ischium and re-enters the pelvis through the lesser 
sacro-sciatic foramen. The artery now crosses the Obturator internus muscle along 
the outer wall of the ischio-rectal fossa, being situated about an inch and a half 
above the lower margin of the ischial tuberosity. It is here contained in a sheath 
SPINE OF 
ISCHIUM 
OBTUR- 
ATOR 
Fig. 402. 
IN- 
TERNAL 
ILIAC 
EXTERNAL 
ILIAC PSOAS 
DORSAL 
ARTERY 
ARTERY 
OF THE 
CORPUS 
INTER. 
PUDIC 
NERVE 
SUPERFICIAL 
PERINEAL 
INFERIOR 
HEMOR- 
RHOIDAL 
INTERNAL 
PUDIC 
ARTERY 
SCIATIC 
ARTERY 
SMALL SCIATIC NERVE 
The Internal Pudic Artery and its Branches in the Male. 
of the obturator fascia, and gradually approaches the margin of the ramus of the 
ischium, along which it ascends forward and upward, pierces the posterior layer of 
the deep perineal fascia, and runs forward along the inner margin of the ramus of 
the pubes; finally, it perforates the anterior layer of the deep perineal fascia and 
divides into its two terminal branches, the dorsal artery of the penis and the artery 
of the corpus cavernosum. 
Relations.-In the first part of its course, within the pelvis, it lies in front of 
the Pyriformis muscle and sacral plexus of nerves and on the outer side of the rec- 
tum (on the left side). As it crosses the spine of the ischium it is covered by the 
Gluteus maximus. In the pelvis it lies on the outer side of the ischio-rectal fossa, 
upon the surface of the Obturator internus muscle, contained in a fibrous canal 
formed by the obturator fascia and the falciform process of the great sacro-sciatic 
ligament. It is accompanied by the pudic veins and the internal pudic nerve. 
Peculiarities.-The internal pudic is sometimes smaller than usual, or fails to give off one 
or two of its usual branches; in such cases the deficiency is supplied by branches derived from 
an additional vessel, the accessory pudic, which generally arises from the pudic artery before its 
exit from the great sacro-sciatic foramen, and passes forward near the base of the bladder, on 
the upper part of the prostate gland, to the perineum; it then perforates the triangular lig- 
ament and gives off the branches usually derived from the pudic artery. The deficiency most 
frequently met with is that in which the internal pudic ends as the artery of the bulb, the artery 
of the corpus cavernosum and arteria dorsalis penis being derived from the accessory pudic. Or 
the pudic may terminate as the superficial perineal, the artery of the bulb being derived, with 
the other two branches, from the accessory vessel. 
The relation of the accessory pudic to the prostate gland and urethra is of the greatest inter- 
est in a surgical point of view, as this vessel is in danger of being wounded in the lateral ope- INTERNAL ILIAC ARTERY. 
589 
ration of lithotomy. The student should also study the position of the internal pudic artery 
and its branches, when running a normal course, with regard to the same operation. The super- 
ficial arteries of the perineum and the transverse perineal are, of necessity, divided in this ope- 
ration, but the hemorrhage from these vessels is seldom excessive; should a ligature be required, 
it can readily be applied on account of their superficial position. The artery of the bulb may 
be divided if the incision be carried too far forward, and wound of this vessel may be attended 
with serious or even fatal consequences.. The main trunk of the internal pudic artery stands a 
risk of being wounded if the incision be carried too far outward; but being bound down by the 
strong obturator fascia and under cover of the ramus of the ischium, the accident is not very 
likely to occur unless the vessel runs an anomalous course. 
Branches.- Within the pelvis the internal pudic gives off' several small branches 
which supply the muscles, sacral nerves, and pelvic viscera. In the perineum the 
following branches are given off: 
Inferior Hemorrhoidal. 
Superficial Perineal. 
Transverse Perineal. 
Artery of the Bulb. 
Artery of the Corpus Cavernosum. 
Dorsal Artery of the Penis. 
The inferior hemorrhoidal are two or three small arteries which arise from 
the internal pudic as it passes above the tuberosity of the ischium. Crossing the 
ischio-rectal fossa, they are distributed to the muscles and integument of the anal 
region. 
The superficial perineal artery supplies the scrotum and muscles and integu- 
ment of the perineum. It arises from the internal pudic, in front of the preceding 
branches, and turns upward, crossing either over or under the Transversus perinaei 
muscle and runs forward, parallel to the pudic arch, in the interspace between the 
Accelerator urinse and Erector penis muscles, both of which it supplies, and is fin- 
ally distributed to the skin of the dartos and scrotum. In its passage through the 
perineum it lies beneath the superficial perineal fascia. 
The transverse perineal is a small branch which arises either from the internal 
pudic or from the superficial perineal artery as it crosses the Transversus perinaei 
muscle. It runs transversely inward along the cutaneous surface of the Transversus 
perinaei muscle, which it supplies, as well as the structures between the anus and 
bulb of the urethra, and anastomoses with the one of the opposite side. 
The artery of the bulb is a large but very short vessel which arises from the 
internal pudic between the two layers of the deep perineal fascia, and, passing nearly 
transversely inward, pierces the bulb of the urethra, in which it ramifies. It gives 
off a small branch which descends to supply Cowper's gland. This artery is of con- 
siderable importance in a surgical point of view, as it is in danger of being wounded 
in the lateral operation of lithotomy-an accident usually attended in the adult with 
alarming hemorrhage. The vessel is sometimes very small, occasionally wanting, or 
even double. It sometimes arises from the internal pudic earlier than usual, and 
crosses the perineum to reach the back part of the bulb. In such a case the vessel 
could hardly fail to be wounded in the performance of the lateral operation for lith- 
otomy. If, on the contrary, it should arise from an accessory pudic, it lies more for- 
ward than usual and is out of danger in the operation. 
The artery of the corpus cavemosum, one of the terminal branches of the 
internal pudic, arises from that vessel while it is situated between the crus penis 
and the ramus of the pubes : piercing the crus penis obliquely, it runs forward in 
the centre of the corpus cavernosum, to which its branches are distributed. 
The dorsal artery of the penis ascends between the crus and pubic symphysis, 
and, piercing the suspensory ligament, runs forward on the dorsum of the penis to 
the glans, where it divides into two branches, which supply the glans and prepuce. 
On the dorsum of the penis it lies immediately beneath the integument, parallel with 
the dorsal vein and the corresponding artery of the opposite side. It supplies the 
integument and fibrous sheath of the corpus cavernosum, sending branches through 
the sheath to anastomose with the preceding vessel. 
The internal pudic artery in the female is smaller than in the male. Its origin 
and course are similar, and there is considerable analogy in the distribution of its 590 
THE ARTERIES. 
branches. The superficial artery supplies the labia pudendi; the artery of the bulb 
supplies the erectile tissue of the bulb of the vagina, whilst the two terminal branches 
supply the clitoris; the artery of the corpus cavernosum, the cavernous body of the 
clitoris; and the arteria dorsalis clitoridis, the dorsum of that organ. 
The Sciatic Artery (Fig. 403), the larger of the two terminal branches of the an- 
terior trunk of the internal iliac, 
is distributed to the muscles on 
the back of the pelvis. It 
passes down to the lower part 
of the great sacro-sciatic for- 
amen, behind the internal pu- 
dic, resting on the sacral plexus 
of nerves and Pyriformis mus- 
cle, and escapes from the pelvis 
between the Pyriformis and 
Coccygeus. It then descends 
in the interval between the tro- 
chanter major and tuberosity 
of the ischium, accompanied by 
the sciatic nerves and covered 
by the Gluteus maximus, and 
divides into branches which 
supply the deep muscles at the 
back of the hip. 
Within the pelvis it dis- 
tributes branches to the Pyri- 
formis, Coccygeus, and Levator 
ani muscles; some hemorrhoi- 
dal branches, which supply the 
rectum, and occasionally take 
the place of the middle hem- 
orrhoidal artery; and vesical 
branches to the base and neck 
of the bladder, vesiculae semi- 
nales, and prostate gland. Ex- 
ternal to the pelvis it gives off 
the following branches: 
Coccygeal. 
Inferior Gluteal. 
Comes nervi ischiadici. 
Muscular. 
Articular. 
The coccygeal branch 
runs inward, pierces the great 
sacro-sciatic ligament, and sup- 
plies the Gluteus maximus, the 
integument, and other struc- 
tures on the back of the coc- 
cyx. 
The branches of the infe- 
rior gluteal, three or four in number, supply the Gluteus maximus muscle, anas- 
tomosing with the gluteal artery in the substance of the muscle. 
The conies nervi ischiadici is a long slender vessel which accompanies the 
great sciatic nerve for a short distance; it then penetrates it, and runs in its sub- 
stance to the lower part of the thigh. 
The muscular branches supply the muscles on the back part of the hip, anas- 
Fig. 403. 
JL of 
I Internal Circumjiefr. 
Hufe riorPerJora ti ng 
\j\ficlotte .Perforating 
Inferior Pc rfe rating 
-Termination of 
PROFUNDA 
Superior Muscular 
-.Superior External Articular 
Inferior Muscular 
The Arteries of the Gluteal and Posterior Femoral Regions. EXTERNAL ILIAC ARTERY. 
591 
tomosing with the gluteal, external branch of the obturator, internal and external 
circumflex, and superior perforating arteries. 
Some articular branches are distributed to the capsule of the hip-joint. 
[From the posterior trunk of the internal iliac arise the ilio-lumbar, the lateral 
sacral, and the gluteal arteries (Fig. 400, p. 585).] 
The Ilio-lumbar Artery ascends beneath the Psoas muscle and external iliac 
vessels to the upper part of the iliac fossa, where it divides into a lumbar and an 
iliac branch. 
The lumbar branch supplies the Psoas and Quadratus lumborum muscles, anas- 
tomosing with the last lumbar artery, and sends a small spinal branch through the 
intervertebral foramen, between the last lumbar vertebra and the sacrum, into the 
spinal canal, to supply the spinal cord and its membranes. 
The iliac branch descends to supply the Iliacus muscle, some offsets, running 
between the muscle and the bone, anastomosing with the iliac branch of the obtu- 
rator : one of these enters an oblique canal to supply the diploe, whilst others run 
along the crest of the ilium, distributing branches to the Gluteal and Abdominal 
muscles, and anastomosing in their course with the gluteal, circumflex iliac, exter- 
nal circumflex, and epigastric arteries. 
The Lateral Sacral Arteries are usually two in number on each side, superior 
and inferior. 
The superior, which is of large size, passes inward, and, after anastomosing 
with branches from the middle sacral, enters the first or second sacral foramen, is 
distributed to the contents of the sacral canal, and, escaping by the corresponding 
posterior sacral foramen, supplies the skin and muscles on the dorsum of the sac- 
rum, anastomosing with the gluteal. 
The inferior passes obliquely across the front of the Pyriformis muscle and 
sacral nerves to the inner side of the anterior sacral foramina, descends on the 
front of the sacrum, and anastomoses over the coccyx with the sacra media and 
opposite lateral sacral arteries. In its course it gives off branches which enter 
the anterior sacral foramina: these, after supplying the bones and membranes of 
the interior of the spinal canal, escape by the posterior sacral foramina, and are 
distributed to the muscles and skin on the dorsal surface of the sacrum, anastomos- 
ing with the gluteal. 
The Gluteal Artery [Fig. 403, p. 590] is the largest branch of the internal 
iliac, and appears to be the continuation of the posterior division of that vessel. It 
is a short, thick trunk which passes out of the pelvis above the upper border of the 
Pyriformis muscle, and immediately divides into a superficial and deep branch. 
Within the pelvis it gives off a few muscular branches to the Iliacus, Pyriformis, 
and Obturator internus, and just previous to quitting that cavity a nutrient artery 
which enters the ilium. 
The superficial branch passes beneath the Gluteus maximus, and divides into 
numerous branches, some of which supply that muscle, whilst others perforate its 
tendinous origin and supply the integument covering the posterior surface of the 
sacrum, anastomosing with the posterior branches of the sacral arteries. 
The deep branch runs between the Gluteus medius and minimus, and subdivides 
into two. Of these, the superior division, continuing the original course of the 
vessel, passes along the upper border of the Gluteus minimus to the anterior supe- 
rior spine of the ilium, anastomosing with the circumflex iliac and ascending branches 
)f the external circumflex artery. The inferior division crosses the Gluteus min- 
mus obliquely to the trochanter major, distributing branches to the Glutei muscles, 
and inosculates with the external circumflex artery. Some branches pierce the 
Gluteus minimus to supply the hip-joint. 
External Iliac Artery (Fig. 400, p. 585). 
The External Iliac Artery is the chief vessel which supplies the lower limb. 
It is larger in the adult than the internal iliac, and passes obliquely downward and 592 
THE ARTERIES. 
outward along the inner border of the Psoas muscle, from the bifurcation of the 
common iliac to Poupart's ligament, where it enters the thigh and becomes the 
femoral artery. The course of this vessel would be indicated by that portion of a 
line drawn from the left side of the umbilicus to a point midway between the ante- 
rior superior spinous process of the ilium and the symphysis pubis, which lies below 
the level of the anterior superior processes. 
Relations.-In front with the peritoneum, subperitoneal areolar tissue, the 
intestines, and a thin layer of fascia derived from the iliac fascia, which surrounds 
the artery and vein. At its origin it is occasionally crossed by the ureter. The 
spermatic vessels descend for some distance upon it near its termination, and it is 
crossed in this situation by the genital branch of the genito-crural nerve and the 
circumflex iliac vein; the vas deferens curves down along the inner side. Behind 
it is in relation •with the external iliac vein, which at the femoral arch lies at its 
inner side; on the left side the vein is altogether internal to the artery. Externally 
it rests against the Psoas muscle, from which it is separated by the iliac fascia. The 
artery rests upon this muscle, near Poupart's ligament. Numerous lymphatic ves- 
sels and glands are found lying on the front and inner side of the vessel. 
Plan of the Relations of the External Iliac Artery 
In Front. 
Peritoneum, intestines, and fascia. 
Spermatic vessels. 
Genite-crural nerve (genital branch). 
Circumflex iliac vein. 
Lymphatic vessels and glands. 
Near 
Poupart's 
Ligament. 
Outer Side. 
Psoas magnus. 
Iliac fascia. 
External 
Iliac. 
Inner Side. 
External iliac vein and vas deferens at 
femoral arch. 
Behind. 
External iliac vein. 
Psoas magnus. 
Surgical Anatomy.-The application of a ligature to the external iliac may be required 
in cases of aneurism of the femoral artery, or in cases of secondary hemorrhage after the latter 
vessel has been tied for popliteal aneurism. This vessel may be secured in any part of its course, 
excepting near its upper end, which is to be avoided on account of the proximity of the great 
stream of blood in the internal iliac, and near its lower end, which should also be avoided on 
account of the proximity of the epigastric and circumflex iliac vessels. One of the chief points in 
the performance of the operation is to secure the vessel without injury to the peritoneum. The 
patient having been placed in the recumbent position, an incision should be made, commencing 
below at a point about three-quarters of an inch above Poupart's ligament and a little external to 
its middle, and running upward and outward, parallel to Poupart's ligament, to a point above 
the anterior superior spine of the ilium. When the artery is deeply seated more room will be 
required, and may be obtained by curving the incision from the point last named inward toward 
the umbilicus for a short distance ; or if the lower part of the artery is to be reached, the surgeon 
may adopt the plan advocated by Sir Astley Cooper, by making an incision close to Poupart's 
ligament from about half an inch outside the external abdominal ring to an inch internal to the 
anterior superior spine of the ilium. This incision being made in the course of the fibres of the 
aponeurosis of the external oblique, is less likely to be followed by a ventral hernia, but there is 
danger of wounding the epigastric artery. Abernethy, who first tied this artery, made his incis- 
ion in the course of the vessel. The abdominal muscles and transversalis fascia having been 
cautiously divided, the peritoneum should be separated from the iliac fossa and pushed toward 
the pelvis, and on introducing the finger to the bottom of the wound the artery may be felt pul- 
sating along the inner border of the Psoas muscle. The external iliac vein is generally found on 
the inner side of the artery, and must be cautiously separated from it by the finger-nail or handle 
of the knife, and the aneurism-needle should be introduced on the inner side between the artery 
and vein. 
Collateral Circulation.-The principal anastomoses in carrying on the collateral circula- 
tion, after the application of a ligature to the external iliac, are-the ilio-lumbar with the cir- 
cumflex iliac; the gluteal with the external circumflex ■ the obturator with the internal circum- 
flex ; the sciatic with the superior perforating and circumflex branches of the profunda artery; 
the internal pudic with the external pudic and with the internal circumflex. When the obtura- EXTERNAL ILIAC ARTERY. 
593 
tor arises from the epigastric, it is supplied with blood by branches either from the internal iliac, 
the lateral sacral, or the internal pudic. The epigastric receives its supply from the internal 
mammary and inferior intercostal arteries and from the internal iliac by the anastomoses of its 
branches with the obturator. 
In the dissection of a limb eighteen years after the successful ligature of the external iliac 
artery by Sir A. Cooper, which is to be found in Guy's Hospital Reports, vol. i. p. 50, the anas- 
tomosing branches are described in three sets: An anterior set: 1, a very large branch from the 
ilio-lumbar artery to the circumflex iliac; 2, another branch from the ilio-lumbar, joined by one 
[from the obturator, and breaking up into numerous tortuous branches to anastomose with the 
external circumflex; 3, two other branches from the obturator, which passed over the brim of 
the pelvis, communicated with the epigastric, and then broke up into a plexus to anastomose 
with the internal circumflex. An internal set: branches given off from the obturator after quit- 
ting the pelvis, which ramified among the Adductor muscles on the inner side of the hip-joint and 
joined most freely with branches of the internal circumflex. A posterior set: 1, three large 
branches from the gluteal to the external circumflex ; 2. several branches from the sciatic around 
the great sciatic notch to the internal and external circumflex and the perforating branches of 
the profunda. 
Branches.-Besides several small branches to the Psoas muscles and the neighbor- 
ing lymphatic glands, the external iliac gives off' two branches of considerable size, the 
Deep Epigastric and Deep Circumflex Iliac. 
The deep epigastric artery arises from the external iliac a few lines above 
Poupart's ligament. It at first descends to reach this ligament, and then ascends 
obliquely along the inner margin of the internal abdominal ring, lying between 
the transversalis fascia and peritoneum, and, passing upward, enters the sheath of 
the Rectus muscle over the semilunar fold of Douglas, having first perforated the 
transversalis fascia. It then ascends on the posterior surface of the muscle, and 
finally divides into numerous branches which anastomose above the umbilicus with 
the terminal branches of the internal mammary and inferior intercostal arteries. It 
is accompanied by two veins, which usually unite into a single trunk before their 
termination in the external iliac vein. As it winds round the internal abdominal 
ring it is crossed on its outer side by the vas deferens in the male and the round 
ligament in the female. 
Branches.-The branches of this vessel are the following: the cremasteric, 
which accompanies the spermatic cord and supplies the Cremaster muscle, anas- 
tomosing with the spermatic artery; a pubic branch, which runs across Poupart's 
ligament, and then descends behind the pubes to the inner side of the femoral ring, 
and anastomoses with offsets from the obturator artery ; muscular branches, some of 
which are distributed to the abdominal muscles and peritoneum, anastomosing with 
the lumbar and circumflex iliac arteries; others perforate the tendon of the Exter- 
nal oblique and supply the integument, anastomosing with branches of the external 
epigastric. 
Peculiarities.-The origin of the epigastric may take place from any part of the external 
iliac between .Poupart's ligament and two inches and a half above it, or it may arise below this 
ligament from the femoral or from the deep femoral. 
Union with Branches.-It frequently arises from the external iliac by a common trunk 
with the obturator. Sometimes the epigastric arises from the obturator, the latter vessel being 
furnished by the internal iliac, or the epigastric may be formed of two branches, one derived 
'from the external iliac, the others from the internal iliac. 
The deep circumflex iliac artery arises from the outer side of the exter- 
nal iliac nearly opposite the epigastric artery. It ascends obliquely outward behind 
Poupart's ligament contained in a fibrous sheath formed by the junction of the trans- 
versalis and iliac fasciae to the anterior superior spinous process of the ilium. It 
then runs along the inner surface of the crest of the ilium to about its middle, where 
it pierces the Transversalis and runs backward between that muscle and the Internal 
oblique, to anastomose with the ilio-lumbar and gluteal arteries. Opposite the 
anterior superior spine of the ilium it gives off a large branch which ascends between 
the Internal oblique and Transversalis muscles, supplying them and anastomosing 
with the lumbar and epigastric arteries. The circumflex iliac artery is accompanied 
by two veins. These unite into a single trunk, which crosses the external iliac 
artery just above Poupart's ligament and enters the external iliac vein. 594 
THE ARTERIES. 
Femoral Artery (Fig. 404.) 
The Femoral Artery1 is the continuation of the external iliac. It commences 
immediately behind Poupart's ligament, midway between the anterior superior spine 
of the ilium and the symphysis 
pubis [or, rather, the spine of 
the pubes], and, passing down 
the fore part and inner side of 
the thigh, terminates at the 
opening in the Adductor mag- 
nus at the junction of the mid- 
dle with the lower third of the 
thigh, where it becomes the pop- 
liteal artery. The upper two- 
thirds of a line drawn from a 
point midway between the ante- 
rior superior spine of the ilium 
and the symphysis pubis [or, 
rather, the spine of the pubes] 
to the inner side of the inner 
condyle of the femur, with the 
thigh abducted and rotated out- 
ward, will indicate the course 
of the artery. This vessel at 
the upper part of the thigh lies 
a little internal to the head of 
the femur; in the lower part of 
its course, on the inner side of 
the shaft of the bone, and be- 
tween these two parts, the vessel 
is far away from the bone. 
In the upper third of the 
thigh the femoral artery is 
very superficial, being covered 
by the integument, inguinal 
glands, and the superficial and 
deep fasciae, and is contained 
in a triangular space called 
"Scarpa's triangle." 
Scarpa's Triangle.-Scar- 
pa's triangle corresponds to the 
depression seen immediately be- 
low the fold of the groin. It is 
a triangular space, the apex of 
which is directed downward, 
and the sides are formed ex- 
ternally by the Sartorius, in- 
ternally by the Adductor longus, 
and [the base] above by Pou- 
part's ligament. The floor of 
this space is formed from 
without inward by the Iliacus, 
Psoas, Pectineus, Adductor longus, and a small part of the Adductor brevis mus- 
cles, and it is divided into two nearly equal parts by the femoral vessels, which 
Fig. 404. 
-Long Saphenous Nerve 
Anastomctica ALagna 
Super, External Articular- 
-.Anastomotica. Magna. 
-Sufi*1.Tnfoi'na IArticular 
Infir. Ex. te-Trial ArtioT- 
-Lifer.Intr.rn.al Artier" 
Anter, Tibial Eecurrcrrt- 
Surgical Anatomy of the Femoral Artery. 
1 [Very often the name "common femoral" is given to the artery from Poupart's ligament to the 
origin of the profunda; "superficial femoral," to the direct continuation of the artery down the 
thigh; and "deep femoral" to the profunda.] FEMORAL ARTERY. 
595 
extend from the middle of its base to its apex, the artery giving off in this situa- 
tion its cutaneous and profunda branches, the vein receiving the deep femoral and 
internal saphenous veins. In this space the femoral artery rests on the inner mar' 
gin of the Psoas muscle, which separates it from the capsular ligament of the hip- 
joint. The artery in this situation has in front of it filaments from the crural 
branch of the genito-crural nerve and branches from the anterior crural, one of 
which is usually of considerable size; behind the artery is the branch to the Pec- 
tineus from the anterior crural. The femoral vein lies at its inner side, between 
the margins of the Pectineus and Psoas muscles [but quickly passes behind the 
artery as we go downward]. The anterior crural nerve lies about half an inch to 
the outer side of the femoral artery, deeply imbedded between the Iliacus and Psoas 
muscles. The femoral artery and vein are enclosed in a strong fibrous sheath 
formed by fibrous and cellular tissue, and by a process of fascia sent inward from 
the fascia lata: the vessels are separated, however, from one another by a thin 
fibrous partition. 
In the middle third of the thigh the femoral artery is more deeply seated, being 
covered by the integument, the superficial and deep fasciae, and the Sartorius, and is 
contained in an aponeurotic canal (Hunter's canal).. This canal, is a depression 
between the Vastus internus externally and the Adductor longus and magnus inter- 
nally, covered over by a dense fibrous band which extends transversely from the 
Vastus internus to the tendons of the Adductor longus and magnus muscles. The 
femoral vein lies on the outer side of the artery, in close apposition with it, and 
still more externally is the internal (long) saphenous nerve. 
Relations.-From above downward the femoral artery rests upon the Psoas 
muscle, which separates it from the margin of the pelvis and capsular ligament of 
the hip; it is next separated from the Pectineus by the profunda vessels and fem- 
oral vein; it then lies upon the Adductor longus; and, lastly, upon the tendon of 
the Adductor magnus, the femoral vein being interposed. To its inner side it is in 
relation above with the femoral vein, and lower down with the Adductor longus 
and Sartorius. To its outer side the Vastus internus separates it from the femur in 
the lower part of its course. 
The femoral vein at Poupart's ligament lies close to the inner side of the artery, 
separated from it by a thin fibrous partition, but as it descends [very soon] gets 
behind it, and then to its outer side. 
The internal saphenous nerve is situated on the outer side of the artery, in the 
middle third of the thigh, beneath the aponeurotic covering, but not usually within 
the sheath of the vessels. Small cutaneous nerves cross the front of the sheath. 
Plan of the Relations of the Femoral Artery. 
In Front. 
Fascia lata. 
Branch of anterior crural nerve to vastus internus. 
Sartorius. 
Long saphenous nerve. 
Aponeurotic covering of Hunter's canal. 
Inner Side. 
Femoral vein (at upper part). 
Adductor longus. 
Sartorius. 
Femoral 
Artery. 
Outer Side. 
Vastus interims. 
Femoral vein (at lower part). 
Behind. 
Psoas magnus. 
Profunda vein. 
Pectineus. 
Adductor longus. 
Femoral vein. 
Adductor magnus. 596 
THE ARTERIES. 
Peculiarities.-Double Femoral reunited.-Four cases are at present recorded in which the 
femoral artery divided into two trunks below the origin of the profunda, and became reunited 
near the opening in the Adductor magnus so as to form a single popliteal artery. One of them 
occurred in a patient operated upon for popliteal aneurism. 
Change of Position.-A similar number of cases have been recorded in which the femoral 
artery was situated at the back of the thigh, the vessel being continuous above with the internal 
iliac, escaping from the pelvis through the great sacro-sciatic foramen, and accompanying the 
great sciatic nerve to the popliteal space, where its division occurred in the usual manner. The 
external iliac in these cases was small and terminated in the profunda. 
Position of the Vein.-The femoral vein is occasionally placed along the inner side of the 
artery throughout the entire extent of Scarpa's triangle, or it may be slit, so that a large vein is 
placed on each side of the artery for a greater or less extent. 
Origin of the Profunda.-This vessel occasionally arises from the inner side, and more 
rarely from the back, of the common trunk; but the more important peculiarity, in a surgical 
point of view, is that which relates to the height at which the vessel arises from the femoral. In 
three-fourths of a large number of cases it arose between one or two inches below Poupart's liga- 
ment ; in a few cases the distance was less than an inch • more rarely, opposite the ligament; 
and in one case, above Poupart's ligament from the external iliac. Occasionally the distance 
between the origin of the vessel and Poupart's ligament exceeds two inches, and in one case it 
was found to be as much as four inches. 
Surgical Anatomy.- Compression of the femoral artery, which is constantly requisite in 
amputations and other operations on the lower limb, and also for the cure of popliteal aneur- 
isms, is most effectually made immediately below Poupart's ligament. In this situation the 
artery is very superficial, and is merely separated from the margin of the acetabulum and front 
of the head of the femur by the Psoas muscle; so that the surgeon, by means of his thumb or a 
compressor, may effectually control the circulation through it. [At this point, where the artery 
is so easily compressed, partial compression should be tried by the student in order to produce the 
" aneurismal thrill " by narrowing the vessel, and so he may make himself familiar with the feel- 
ing. By partial compression on the living model by a stethoscope the " aneurismal bruit " may be 
heard. The same can be done in the abdominal aorta, and might give rise to the erroneous 
diagnosis of aneurism.] This vessel may also be compressed in the middle third of the thigh by 
placing a compress over the artery beneath the tourniquet, and directing the pressure from within 
outward, so as to compress the vessel against the inner side of the shaft of the femur. 
The application of a ligature to the femoral artery may be required in cases of wound 
or aneurism of the arteries of the leg, of the popliteal or femoral, and the vessel may be exposed 
and tied in any part of its course, The great depth of this vessel at its lower part, its close con- 
nection with important structures, and the density of i+s sheath render the operation in this situ- 
ation one of much greater difficulty than the application of a ligature at its upper part, where it 
is more superficial. 
Ligature of the femoral artery within two inches of its origin [i. e. of the " common femoral "] 
is usually considered unsafe, on account of the connection of large branches with it, the epigastric 
and deep circumflex iliac arising just above its origin ; the profunda, from one to inches below; 
occasionally also one of the circumflex arteries arises from the vessel in the interspace between 
these. The profunda sometimes arises higher than the point above mentioned, and rarely 
between two and three inches (in one case four) below Poupart's ligament. It would appear, 
then, that the most favorable situation for the application of a ligature to the femoral is between 
four and five inches from its point of origin. In order to expose the artery in this situation, an 
incision between two and three inches long should be made in the course of the vessel, the 
patient lying in the recumbent position with the limb slightly flexed and abducted. A large 
vein is frequently met with, passing in the course of the artery to join the saphena; this must 
be avoided, and, the fascia lata having been cautiously divided and the Sartorius exposed, that 
muscle must be drawn outward in order to fully expose the sheath of the vessels. The finger 
being introduced into the wound and the pulsation of the artery felt, the sheath should be divided 
over the artery to a sufficient extent to allow of the introduction of the ligature, but no farther; 
otherwise the nutrition of the coats of the vessel may be interfered with, or muscular branches 
which arise from the vessel at irregular intervals may be divided. In this part of the operation 
a small nerve which crosses the sheath should be avoided. The aneurism-needle must be care- 
fully introduced and kept close to the artery to avoid the femoral vein, which lies behind the 
vessel in this part of its course. 
To expose the artery in Hunter's canal an incision should be made through the integument 
between three and four inches in length, a finger's breadth internal to the line of the artery in 
the middle of the thigh-i. e. midway between the groin and the knee. The fascia lata having been 
divided and the Sartorius muscle exposed, it should be drawn inward, when the strong fascia 
which is stretched across from the Adductors to the Vastus internus will be exposed, and must 
be freely divided ; the sheath of the vessels is now seen, and must be opened, and the artery 
secured by passing the aneurism-needle between the vein and artery in the direction from with- 
out inward. The femoral vein in this situation lies on the outer side of the artery, the long 
saphenous nerve on its anterior and outer side. 
It has been seen that the femoral artery occasionally divides into two trunks below the origin 
/jf the profunda. If in the operation for tying the femoral two vessels are met with, the surgeon 
should alternately compress each, in order to ascertain which vessel is connected with the aneur- FEM 0 Ji AL AliTEliY. 
597 
ismal tumor or with the bleeding from the wound, and that one only should be tied which con- 
trols the pulsation or hemorrhage. If, however, it is necessary to compress both vessels before 
the circulation in the tumor is controlled, both should be tied, as it would be probable that they 
became reunited, as in the four instances referred to above. 
Collateral Circulation.-When the common femoral is tied the main channels for carry- 
ing on the circulation are the anastomoses of the gluteal and circumflex iliac arteries above with 
the external circumflex below; of the obturator and sciatic above with the internal circumflex 
below; of the ilio-lumbar with the external circumflex; and of the comes nervi ischiadici with 
the arteries in the ham. 
The principal agents in carrying on the collateral circulation after ligature of the superficial 
femoral artery are, according to Sir A. Cooper, as follows z1 
" The arteria profunda formed the new channel for the blood." " The first artery sent off 
passed down close to the back of the thigh-bone, and entered the two superior articular branches 
of the popliteal artery." 
" The second new large vessel arising from the profunda at the same part with the former 
passed down by the inner side of the Biceps muscle to a branch of the popliteal which was dis- 
tributed to the Gastrocnemius muscle; whilst a third artery, dividing into several branches, 
passed down with the sciatic nerve behind the knee-joint, and some of its branches united them- 
selves with the inferior articular arteries of the popliteal, with some recurrent branches of those 
arteries, with arteries passing to the Gastrocnemii, and, lastly, with the origin of the anterior 
and posterior tibial arteries." 
" It appears, then, that it is those branches of the profunda which accompany the sciatic 
nerve that are the principal supporters of the new circulatipn." 
In Porta's work2 (Tab. xii., xiii.) is a good representation of the collateral circulation after the 
ligature of the femoral artery. The patient had survived the operation three years. The lower part 
of the artery is at least as large as the upper ; about two inches of the vessel appear to have been 
obliterated.' The external and internal circumflex arteries are seen anastomosing by a great 
number of branches with the lower branches of the femoral (muscular and anastomotica magna) 
and with the articular branches of the popliteal. The branches from the external circumflex are 
extremely large and numerous. One very distinct anastomosis can be traced between this artery 
on the outside and the anastomotica magna on the inside through the intervention of the superior 
external articular artery, with which they both anastomose; and blood reaches even the anterior 
tibial recurrent from the external circumflex by means of anastomosis with the same external 
articular artery. The perforating branches of the profunda are also seen bringing blood round 
the obliterated portion of the artery into long branches (muscular) which have been given off just 
below that portion. The termination of the profunda itself anastomoses most freely with the 
superior external articular. A long branch of anastomosis is also traced down from the internal 
iliac by means of the comes nervi ischiadici of the sciatic, which anastomoses on the popliteal 
nerves with branches from the popliteal and posterior tibial arteries. In this case the anasto- 
mosis had been too free, since the pulsation and growth of the aneurism recurred, and the patient 
died after ligature of the external iliac. 
There is an interesting preparation in the Museum of the Royal College of Surgeons of a 
limb on which John Hunter had tied the femoral artery fifty years before the patient's death. 
The whole of the superficial femoral and popliteal artery seems to have been obliterated. The 
anastomosis by means of the comes nervi ischiadici, which is shown in Porta's plate, is distinctly 
seen: the external circumflex and the termination of the profunda artery seem to have been the 
chief channels of anastomosis; but the injection has not been a very successful one. 
Branches.-The branches of the femoral artery are the 
Superficial Epigastric. 
Superficial Circumflex Iliac. 
Superficial External Pudic. 
Deep External Pudic. 
External Circumflex. 
Internal Circumflex. 
Three Perforating. 
Profunda. 
Muscular. 
Anastomotica magna. 
The superficial epigastric arises from the femoral about half an inch below 
Poupart's ligament, and, passing through the saphenous opening in the fascia lata, 
ascends on to the abdomen, in the superficial fascia covering the External oblique 
muscle, nearly as high as the umbilicus. It distributes branches to the inguinal 
glands, the superficial fascia, and the integument, anastomosing with branches of 
the deep epigastric and internal mammary arteries. 
The superficial circumflex iliac, the smallest of the cutaneous branches, arises 
1 Med.-Chir. Trans., vol. ii. 1811. 
2 Alterazioni patologiche delle Arlerie. 598 
THE ARTERIES. 
close to the preceding, and, piercing the fascia lata, runs outward, parallel with 
Poupart's ligament, as far as the crest of the ilium, dividing into branches which 
supply the integument of the groin, the superficial fascia, and the inguinal glands, 
anastomosing with the circumflex iliac and with the gluteal and external circumflex 
arteries. 
The superficial external pudic (superior) arises from the inner side of the fem- 
oral artery close to the preceding vessels, and, after passing through the saphenous 
opening, courses inward across the spermatic cord, to be distributed to the integu- 
ment on the lower part of the abdomen, the penis and scrotum in the male, and the 
labium in the female, anastomosing with branches of the internal pudic. 
The deep external pudic (inferior), more deeply seated than the preceding, 
passes inward on the Pectineus muscle, covered by the fascia lata, which it pierces 
at the inner border of the thigh, its branches being distributed in the male to the 
integument of the scrotum and perineum, and in the female to the labium, anasto- 
mosing with branches of the superficial perineal artery. 
The Profunda Femoris (deep femoral artery') nearly equals the size of the 
superficial femoral. It arises from the outer and back part of the femoral artery 
from one to two inches below Poupart's ligament. It at first lies on the outer side 
of the superficial femoral, and then passes behind it and the femoral vein to the 
inner side of the femur, and, passing downward beneath the Adductor longus, ter- 
minates at the lower third of the thigh in a small branch which pierces the Adduc- 
tor magnus (and from this circumstance is sometimes called the fourth perforating 
artery), to be distributed to the flexor muscles on the back of the thigh, anastomos- 
ing with branches of the popliteal and inferior perforating arteries. 
Relations.-Behind, it lies first upon the Iliacus, and then on the Pectineus, 
Adductor brevis, and Adductor magnus muscles. In front it is separated from the 
femoral artery, above by the femoral and profunda veins, and below by the Adduc- 
tor longus. On its outer side the origin of the Vastus internus separates it from 
the femur. 
Plan of the Relations of the Profunda Artery. 
In Front. 
Femoral and profunda veins. 
Adductor longus. 
Outer Side. 
Vastus interims. 
Profunda. 
Behind. 
Iliacus. 
Pectineus. 
Adductor brevis. 
Adductor magnus. 
The External Circumflex Artery supplies the muscles on the front of the 
thigh. It arises from the outer side of the profunda, passes horizontally out- 
ward between the divisions of the anterior crural nerve, and behind the Sartorius 
and Rectus muscles, and divides into three sets of branches-ascending, transverse, 
and descending. 
The ascending- branches pass upward, beneath the Tensor vaginae femoris mus- 
cle, to the outer side of the hip, anastomosing with the terminal branches of the 
gluteal and circumflex iliac arteries. 
The descending- branches, three or four in number, pass downward, behind 
the Rectus, upon the Vasti muscles, to which they are distributed, one or two pass- 
ing beneath the Vastus externus as far as the knee, anastomosing with the superior 
articular branches of the popliteal artery. These are accompanied by the branch of 
the anterior crural nerve to the Vastus externus. POPLITEAL ARTERY. 
599 
The transverse branches, the smallest and least numerous, pass outward over 
the Crureus, pierce the Vastus externus, and wind round the femur to its back part 
just below the great trochanter, anastomosing at the back of the thigh with the 
internal circumflex, sciatic, and superior perforating arteries. 
The Internal Circumflex Artery [Fig. 403, p. 590], smaller than the external, 
arises from the inner and back part of the profunda, and winds round the inner side 
of the femur, between the Pectineus and Psoas muscles. On reaching the upper 
border of the Adductor brevis it gives off two branches, one of which passes inward 
to be distributed to the Adductor muscles, the Gracilis, and Obturator externus, 
anastomosing with the obturator artery; the other descends, and passes beneath the 
Adductor brevis to supply it and the great Adductor; while the continuation of the 
vessel passes backward between the Quadratus femoris and upper border of the 
Adductor magnus, anastomosing with the sciatic, external circumflex, and superior 
perforating arteries ("the crucial anastomosis'Opposite the hip-joint this branch 
gives off an articular vessel which enters the joint beneath the transverse ligament, 
and, after supplying the adipose tissue, passes along the round ligament to the head 
of the bone. 
The Perforating1 Arteries (Fig. 403), usually three in number, are so called from 
their perforating the tendons of the Adductor brevis and magnus muscles to reach 
the back of the thigh. The first is given off above the Adductor brevis, the second 
in front of that muscle, and the third immediately below it. 
The first or superior perforating artery passes backward between the Pec- 
tineus and Adductor brevis (sometimes perforates the latter); it then pierces the 
Adductor magnus close to the linea aspera, and divides into branches which supply 
both Adductors, the Biceps, and Gluteus maximus muscles, anastomosing with the 
sciatic, internal and external circumflex, and middle perforating arteries. 
The second or middle perforating artery, larger than the first, pierces the 
tendons, of the Adductor brevis and Adductor magnus muscles, and divides into 
ascending and descending branches, which supply the flexor muscles of the thigh, 
anastomosing with the superior and inferior perforating. The nutrient artery of the 
femur is usually given oft' from this branch. 
The third or inferior perforating artery is given off below the Adductor bre- 
vis ; it pierces the Adductor magnus and divides into branches which supply the 
flexor muscles of the thigh, anastomosing above with the perforating arteries, and 
below with the terminal branches of the profunda and the muscular branches of the 
popliteal. 
[The fourth perforating artery is the termination of the profunda femoris.] 
Muscular branches are given off from the superficial femoral throughout its 
entire course. They vary from two to seven in number, and supply chiefly the 
Sartorius and Vastus internus. 
The anastomotica magna arises from the femoral artery just before it passes 
through the tendinous opening in the Adductor magnus muscle, and divides into a 
superficial and deep branch. 
The superficial branch accompanies the long saphenous nerve beneath the Sar- 
torius, and, piercing the fascia lata, is distributed to the integument. 
The deep branch descends in the substance of the Vastus internus, lying in 
front of the tendon of the Adductor magnus, to the inner side of the knee, where 
it anastomoses with the superior internal articular artery and recurrent branch of 
the anterior tibial. A branch from this vessel crosses outward above the articular 
surface of the femur, forming an anastomotic arch with the superior external artic- 
ular artery, and supplies branches to the knee-joint. 
Popliteal Artery. 
The Popliteal Artery commences at the termination of the femoral at the open- 
ing in the Adductor magnus, and, passing obliquely downward and outward behind 
the knee-joint to the lower border of the Popliteus muscle, divides into the anterior 600 
THE ARTERIES. 
and posterior tibial arteries. Through the whole of this extent the artery lies in 
the popliteal space. 
The Popliteal Space (Fig. 405, p. 604). 
Dissection.-A vertical incision about eight inches in length should be made along the 
back part of the knee-joint, connected above and below by a transverse incision from the inner 
to the outer side of the limb. The flaps of integument included between these incisions should 
be reflected in the direction shown in Fig. 337, p. 473. 
On removing the integument the superficial fascia is exposed, and ramifying in 
it along the middle line are found some filaments of the small sciatic nerve, and 
toward the inner part some offsets from the internal cutaneous nerve. 
The superficial fascia having been removed, the fascia lata is brought into view. 
In this region it is strong and dense, being strengthened by transverse fibres and 
firmly attached to the tendons on the inner and outer sides of the space. It is 
sometimes perforated below by the external saphenous vein. This fascia having 
been reflected back in the same direction as the integument, the small sciatic nerve 
and external saphenous vein are seen immediately beneath it in the middle line. If 
the loose adipose tissue is now removed, the boundaries and contents of the space 
may be examined. 
Boundaries.-The popliteal space, or the ham, occupies the lower third of the 
thigh and the upper fifth of the leg, extending from the aperture in the Adductor 
magnus to the lower border of the Popliteus muscle. It is a lozenge-shaped space, 
being widest at the back part of the knee-joint and deepest above the articular end 
of the femur. It is bounded externally, above the joint, by the Biceps, and below 
the joint by the Plantaris and external head of the Gastrocnemius; internally, above 
the joint, by the Semitendinosus, Semimembranosus, Gracilis, and Sartorius; below 
the joint, by the inner head of the Gastrocnemius. 
Above, it is limited by the apposition of the inner and outer hamstring muscles; 
below, by the junction of the two heads of the Gastrocnemius. The floor is formed 
by the lower part of the posterior surface of the shaft of the femur, the posterior 
ligament of the knee-joint, the upper end of the tibia, and the fascia covering the 
Popliteus muscle, and the space is covered in by the fascia lata. [It will well repay 
the student to notice closely the boundaries of the popliteal space on the living model, 
both at rest and in action (and especially resisted action) and in varying degrees of 
flexion. The thin tendon of the Semitendinosus can always be differentiated from 
its thicker neighbor, the Semimembranosus, the tendon of which lies farther from 
the middle line of the ham, though higher up its belly is the inner border of the 
space. The tendons of the Gracilis and Sartorius are usually obscure, unless strongly 
contracted. The Biceps tendon is easily felt. The different degrees of tension of 
the deep fascia are very important. In extension it is tense, and nothing can be 
felt beneath it; in complete flexion the parts are inaccessible, the thigh and the leg 
being apposed; in partial flexion the artery can be felt and compressed. The nerve 
is obscurely felt.] 
Contents.-It contains the popliteal vessels and their branches, together with 
the termination of the external saphenous vein, the internal and external popliteal 
nerves and their branches, the small sciatic nerve, the articular branch from the 
obturator nerve, a few small lymphatic glands, and a considerable quantity of loose 
adipose tissue. 
Position of Contained Parts.-The internal popliteal nerve descends in the 
middle line of the space, lying superficial and crossing the artery from without 
inward. The external popliteal nerve descends on the outer side of the space, lying 
close to the tendon of the Biceps muscle. More deeply at the bottom of the space 
are the popliteal vessels, the vein lying superficial and a little external to the artery, 
to which it is closely united by dense areolar tissue; sometimes the vein is placed 
on the inner instead of the outer side of the artery; or the vein may be double, the 
artery lying between the two venae comites, which are usually connected by short POPLITEAL ARTERY. 
601 
transverse branches. More deeply and close to the surface of the bone is the pop- 
liteal artery, and passing off from it at right angles are its articular branches. The 
articular branch from the obturator nerve descends upon the popliteal artery to sup- 
ply the knee, and occasionally there is found deep in the space an articular filament 
from the great sciatic nerve. The popliteal lymphatic glands, four or five in num- 
ber, are found surrounding the artery; one usually lies superficial to the vessel, 
another is situated between it and the bone, and the rest are placed on either side of 
it. The bursae usually found in this place are : 1. On the outer side one beneath the 
outer head of the Gastrocnemius (which sometimes communicates with the joint), and 
one beneath the tendon of the Popliteus, which is almost always an extension of the 
synovial membrane. Sometimes also there is a bursa above the tendon of the Pop- 
liteus, between it and the external lateral ligament. 2. On the inner side of the 
joint there is a large bursa between the inner head of the Gastrocnemius and the 
femur, which sends a prolongation between the tendons of the Gastrocnemius and 
Semimembranosus, and lies in contact with the ligament of Winslow. This bursa 
often communicates with the joint. There is a second bursa between the tendon of 
the Semimembranosus and the head of the tibia, and sometimes a bursa between 
the tendons of the Semitendinosus and Semimembranosus. 
The Popliteal Artery, in its course downward from the aperture in the Adduc- 
tor magnus to the lower border of the Popliteus muscle, rests first on the inner and 
then on the posterior surface of the femur; in the middle of its course, on the pos- 
terior ligament of the knee-joint; and below, on the fascia covering the Popliteus 
muscle. Superficially, it is covered above by the Semimembranosus ; in the middle 
of its course, by a quantity of fat which separates it from the deep fascia and integ- 
ument ; and below, it is overlapped by the Gastrocnemius, Plantaris, and Soleus 
muscles, the popliteal vein, and the internal popliteal nerve. The popliteal vein, 
which is intimately attached to the artery, lies superficial and external to it, until 
near its termination, when it crosses it and lies to its inner side. The popliteal 
nerve is still more superficial and external, crossing, however, the artery below the 
joint and lying on its inner side. Laterally, the artery is bounded by the muscles 
which are situated on either side of the popliteal space. 
Peculiarities in Point of Division.-Occasionally the popliteal artery divides prema- 
turely into its terminal branches; this division occurs most frequently opposite the knee-joint. 
Unusual Branches.-The artery sometimes divides into the anterior tibial and peroneal, 
the posterior tibial being wanting or very small. In a single case the popliteal was found to 
divide into three branches, the anterior and posterior tibial and peroneal. 
Surgical Anatomy.-Ligature of the popliteal artery is required in cases of wound of 
that vessel, but for aneurism of the posterior tibial it is preferable to tie the superficial femoral. 
The popliteal may be tied in the upper or lower part of its course; but in the middle of the ham 
the operation is attended with considerable difficulty, from the great depth of the artery and from 
the extreme degree of tension of the lateral boundaries of the space. 
In order to expose the vessel in the upper part of its course, the patient should be placed in 
the prone position with the limb extended. An incision about three inches in length should 
then be made through the integument along the posterior margin of the Semimembranosus, and, 
the fascia lata having been divided, this muscle must be drawn inward. The internal popliteal 
nerve will be first exposed, lying very superficial and external to the artery ; beneath this will 
be seen the popliteal vein, and still deeper and to its inner side the artery. The vein and nerve 
must be cautiously separated from the artery and the aneurism-needle passed around the vessel 
from without inward. 
To expose the vessel in the lower part of its course, where the artery lies between the two 
heads of the Gastrocnemius, the patient should be placed in the same position as in the pre- 
ceding operation. An incision should then be made through the integument in the middle line, 
commencing opposite the bend of the knee-joint, care being taken to avoid the external saph- 
enous vein and nerve. After dividing the deep fascia and separating some dense cellular mem- 
brane, the artery, vein, and nerve will be exposed, descending between the two heads of the 
Gastrocnemius. Some muscular branches of the popliteal should be avoided if possible, or, if 
divided tied immediately. The leg being now flexed, in order the more effectually to separate 
the two heads of the Gastrocnemius the nerve should be drawn inward and the vein outward, 
and the aneurism-needle passed between the artery and vein from without inward. 602 
THE ARTERIES. 
Plan of Relations of Popliteal Artery. 
In Front. 
Femur. 
Ligamentum posticum. 
Popliteus. 
Inner Side. 
Semimembranosus. 
Internal condyle. 
Gastrocnemius (inner head). 
Outer Side. 
Biceps. 
Outer condyle. 
Gastrocnemius (outer head). 
Plantaris. 
Popliteal 
Artery. 
Behind. 
Semimembranosus. 
Fascia. 
Popliteal vein. 
Internal popliteal nerve. 
Gastrocnemius. 
Plantaris. 
Soleus. 
The branches of the popliteal artery are the 
Superior. 
Inferior or Sural. 
Muscular 
Cutaneous. 
Superior External Articular. 
Superior Internal Articular. 
Azygos Articular. 
Inferior External Articular. 
Inferior Internal Articular. 
The superior muscular branches, two or three in number, arise from the upper 
part of the popliteal artery, and are distributed to the Vastus externus and flexor 
muscles of the thigh, anastomosing with the inferior perforating and terminal 
branches of the profunda. 
The inferior muscular (sural) are two large branches which are distributed to 
the two heads of the Gastrocnemius and to the Plantaris muscle. They arise from 
the popliteal artery opposite the knee-joint. 
Cutaneous branches descend on each side and in the middle of the limb 
between the Gastrocnemius and integument; they arise separately from the 
popliteal artery or from some of its branches, and supply the integument of 
the calf. 
The superior articular arteries, two in number, arise one on either side of the 
popliteal, and wind round the femur immediately above its condyles to the front of 
the knee-joint. The internal branch passes beneath the tendon of the Adductor 
magnus, and divides into two, one of which supplies the Vastus internus, inoscu- 
lating with the anastomotica magna and inferior internal articular; the other ram- 
ifies close to the surface of the femur, supplying it and the knee-joint, and anasto- 
mosing with the superior external articular artery. The external branch passes 
above the outer condyle, beneath the tendon of the Biceps, and divides into a super- 
ficial and deep branch : the superficial branch supplies the Vastus externus, and 
anastomoses with the descending branch of the external circumflex artery ; the deep 
branch supplies the lower part of the femur and knee-joint, and forms an anasto- 
motic arch across the bone with the anastomotica magna artery. 
The azygos articular is a small branch arising from the popliteal artery oppo- 
site the bend of the knee-joint. It pierces the posterior ligament, and supplies the 
ligaments and synovial membrane in the interior of the articulation. 
The inferior articular arteries, two in number, arise from the popliteal beneath 
the Gastrocnemius, and wind round the head of the tibia below the joint. The 
internal one passes below the inner tuberosity, beneath the internal lateral ligament, 
at the anterior border of which it ascends to the front and inner side of the joint ANTERIOR TIBIAL ARTERY. 
603 
to supply the head of the tibia and the articulation of the knee. The external one 
passes outward above the head of the fibula to the front of the knee-joint, lying in 
its course beneath the outer head of the Gastrocnemius, the external lateral liga- 
ment, and the tendon of the Biceps muscle, and divides into branches which anas- 
tomose with the inferior internal articular artery, the superior articular arteries, and 
the recurrent branch of the anterior tibial. 
Anterior Tibial Artery (Fig. 406). 
The Anterior Tibial Artery commences at the bifurcation of the popliteal at 
the lower border of the Popliteus muscle, passes forward between the two heads of 
the Tibialis posticus, and through the aperture left between the bones at the upper 
part of the interosseous membrane, to the deep part of the front of the leg; it then 
descends on the anterior surface of the interosseous membrane and of the tibia to 
the bend of the ankle-joint, where it lies more superficially and becomes the dorsalis 
pedis. A line drawn from the inner side of the head of the fibula to midway 
between the two malleoli will mark the course of the artery, the point where the 
artery comes in front of the interosseous membrane being in this line one and a 
quarter inches below the level of the head of the fibula. 
Relations.-In the upper two-thirds of its extent it rests upon the interosseous 
membrane, to which it is connected by delicate fibrous arches thrown across it; 
in the lower third, upon the front of the tibia and the anterior ligament of the 
ankle-joint. In the upper third of its course it lies between the Tibialis anticus 
and Extensor longus-digitorum; in the middle third, between the Tibialis anticus 
and Extensor proprius pollicis. At the bend of the ankle it is crossed by the ten- 
don of the Extensor proprius pollicis, and lies between it and the innermost tendon 
of the Extensor longus digitorum. It is covered in the upper two-thirds of its 
course by the muscles which lie on either side of it and by the deep fascia; in the 
lower third, by the integument, annular ligament, and fascia. 
The anterior tibial artery is accompanied by two veins (venae comites) which lie 
one on either side of the artery; the anterior tibial nerve lies at first to its outer 
side, and about the middle of the leg is placed superficial to it; at the lower part 
of the artery the nerve is generally again on the outer side. [See Rule, p. 562.] 
Plan of the Relations of the Anterior Tibial Artery. 
In Front. 
Integument, superficial and deep fasciae. 
Anterior tibial nerve. 
Tibialis anticus (overlaps it in upper part of leg). 
Extensor longus digitorum 
Extensor proprius pollicis 
(overlap it slightly). 
Inner Side. 
Tibialis anticus. 
Extensor proprius pollicis 
(crosses it at its lower part). 
Outer Side. 
Anterior tibial nerve. 
Extensor longus digitorum. 
Extensor proprius pollicis. 
Anterior 
Tibial. 
Behind. 
Interosseous membrane. 
Tibia. 
Anterior ligament of ankle-joint. 
Peculiarities in Size.-This vessel may be diminished in size, may be deficient to a 
greater or less extent, or may be entirely wanting, its place being supplied by perforating 
branches from the posterior tibial or by the anterior division of the peroneal artery. 
Course.-The artery occasionally deviates in its course toward the fibular side of the leg, 
regaining its usual position beneath the annular ligament at the front of the ankle. In two 
instances the vessel has been found to approach the surface in the middle of the leg, being 
covered merely by the integument and fascia below that point. 
Surgical Anatomy -The anterior tibial artery may be tied in the upper or lower part of 604 
THE ARTERIES. 
Fig. 405. 
Fig. 406. 
Inferior ' 
External 
L Inferior 
Internal 
Artiddar 
Sural 
~Arteries 
Anterior 
Ttbtttll 
Recurrent 
Vi 
An te ria/r leronea Zl J 
- XnternaT 
-Anterior Peroneal 
Esc,terna I _ 
Alalleular 
' CuuLniunlcart'i 
Internals Calcanean 
The Popliteal, Posterior Tibial, and Peroneal 
Arteries. 
Surgical Anatomy of the Anterior Tibial and 
Dorsalis Pedis Arteries. 
the leg. In the upper part the operation is attended with great difficulty, on account of the 
depth of the vessel from the surface. An incision about four inches in length should be made DORSALIS PEDIS ARTERY. 
605 
through the integument, midway between the spine of the tibia and the outer margin of the 
fibula, the fascia and intermuscular septum between the Tibialis anticus and Extensor longus 
digitorum being divided to the same extent. The foot must be flexed to relax these muscles, and 
they must be separated from each other by the finger. The artery is then exposed deeply 
seated, lying upon the interosseous membrane, the nerve lying externally and one of the venae 
comites on either side ; these must be separated from the artery before the aneurism-needle is 
passed around it. [Once that the interspace between the Tibialis anticus and the Extensor longus 
digitorum is reached, it is of the utmost importance to remember that the Extensor proprius pol- 
licis is interposed between these muscles, and does not reach the surface of the leg in the upper 
two-thirds. Hence in going downward the interspace between the Tibialis anticus and Extensor 
longus digitorum bifurcates like an inverted X, the two legs of the X having between them the 
Extensor proprius pollicis ; and one may easily get to the wrong side of this muscle. The artery 
lies in the space between the Tibialis anticus and the Extensor proprius pollicis. To find the 
anterior tibial artery stick to the anterior tibial musclei] 
To tie the vessel in the lower third of the leg above the ankle-joint, an incision about three 
inches in length should be made through the integument between the tendons of the Tibialis 
anticus and Extensor proprius pollicis muscles, the deep fascia being divided to the same extent; 
the tendon on either side should be held aside, when the vessel will be seen lying upon the tibia, 
with the nerve superficial to it, and one of the venae comites on either side. 
In order to secure the artery over the instep an incision should be made on the fibular side 
of the tendon of the Extensor proprius pollicis, between it and the innermost tendon of the long 
Extensor ; the deep fascia having been divided, the artery will be exposed, the nerve lying either 
superficial to it or to its outer side. 
The branches of the anterior tibial artery aie the 
Recurrent Tibial. 
Muscular. 
Internal Malleolar. 
External Malleolar. 
The recurrent branch arises from the anterior tibial as soon as that vessel has 
passed through the interosseous space; it ascends in the Tibialis anticus muscle, 
and ramifies on the front and sides of the knee-joint, anastomosing with the articu- 
lar branches of the popliteal and with the anastomotica magna. 
The muscular branches are numerous; they are distributed to the muscles 
which lie on either side of the vessel, some piercing the deep fascia to supply the 
integument, others passing through the interosseous membrane and anastomosing 
with the branches of the posterior tibial and peroneal arteries. 
The malleolar arteries supply the ankle-joint. The mternaZ arises about two 
inches above the articulation, and passes beneath the tendons of the Extensor pro- 
prius pollicis and Tibialis anticus to the inner ankle, upon which it ramifies, anas- 
tomosing with branches of the posterior tibial and internal plantar arteries and with 
the internal calcanean from the posterior tibial. The external passes beneath the 
tendons of the Extensor longus digitorum and Peroneus tertius, and supplies the 
outer ankle, anastomosing with the anterior peroneal artery and with ascending 
branches from the tarsal branch of the dorsalis pedis. 
Dorsalis Pedis Artery (Fig. 406, p. 604). 
The Dorsalis Pedis, the continuation of the anterior tibial, passes forward from 
the bend of the ankle along the tibial side of the foot to the back part of the first 
interosseous space, where it divides into two branches, the dorsalis hallucis and 
communicating. 
Relations.-This vessel in its course forward rests upon the astragalus, sca- 
phoid, and internal cuneiform bones and the ligaments connecting them, being 
covered by the integument and fascia, and crossed near its termination by the inner- 
most tendon of the Extensor brevis digitorum. On its tibial side is the tendon of 
the Extensor proprius pollicis; on its fibular side are the innermost tendon of the 
Extensor longus digitorum and the termination of the anterior tibial nerve. It is 
accompanied by two veins. 606 
THE ARTERIES. 
Plan of the Relations of the Dorsalis Pedis Artery. 
In Front. 
Integument and fascia. 
Innermost tendon of Extensor brevis digitorum 
Fibular Side. 
Extensor longus digitorum. 
Anterior tibial nerve. 
Tibial Side. 
Extensor proprius pollicis. 
Dorsalis 
Pedis. 
Behind. 
Astragalus. 
Scaphoid. 
Internal cuneiform and their ligaments. 
Peculiarities in Size.-The dorsal artery of the foot may be larger than usual to compen- 
sate for a deficient plantar artery ; or it may be deficient in its terminal branches to the toes, 
which are then derived from the internal plantar ; or its place may be supplied altogether by a 
large anterior peroneal artery. 
Position.-The artery frequently curves outward, lying external to the line between the 
middle of the ankle and the back part of the first interosseous space. 
Surgical Anatomy.-This artery may be tied by making an incision through the integ- 
ument, between two and three inches in length, on the fibular side of the tendon of the Exten- 
sor proprius pollicis, in the interval between it and the inner border of the short Extensor 
muscle. The incision should not extend farther forward than the back part of the first interos- 
seous space, as the artery divides in that situation. The deep fascia being divided to the same 
extent, the artery will be exposed, the nerve lying upon its outer side. 
Branches.-The branches of the dorsalis pedis are the 
Tarsal. 
Metatarsal. 
Dorsalis pollicis or hallucis. 
Communicating. 
Interosseous. 
The tarsal artery arises from the dorsalis pedis as that vessel crosses the sca- 
phoid bone; it passes in an arched direction outward, lying upon the tarsal bones 
and covered by the Extensor brevis digitorum; it supplies that muscle and the 
articulations of the tarsus, and anastomoses with branches from the metatarsal, 
external malleolar, peroneal, and external plantar arteries. 
The metatarsal arises a little anterior to the preceding; it passes outward to 
the outer part of the foot, over the bases of the metatarsal bones, beneath the ten- 
dons of the short Extensor, its direction being influenced by its point of origin, 
and it anastomoses with the tarsal and external plantar arteries. This vessel gives 
off three branches: the interosseous, which pass forward upon the three outer 
Dorsal interossei muscles, and in the clefts between the toes divide into two dorsal 
collateral branches for the adjoining toes. At the back part of each interosseous 
space these vessels receive the posterior perforating branches from the plantar arch, 
and at the fore part of each interosseous space they are joined by the anterior per- 
forating branches from the digital artery. The outermost interosseous artery gives 
off a branch which supplies the outer side of the little toe. 
The dorsalis hallucis runs forward along the outer border of the first meta- 
tarsal bone, and at the cleft between the first and second toes divides into two 
branches, one of which passes inward beneath the tendon of the Extensor proprius 
pollicis, and is distributed to the inner border of the great toe; the other branch 
bifurcates to supply the adjoining sides of the great and second toes. 
The communicating artery dips down into the sole of the foot between the 
two heads of the first Dorsal interosseous muscle, and -inosculates with the termina- 
tion of the external plantar artery to complete the plantar arch. It here gives off 
two digital branches: one runs along the inner side of the great toe on its plantar 
surface; the other passes forward along the first metatarsal space, and bifurcates 
for the supply of the adjacent sides of the great and second toes. POSTERIOR TIBIAL ARTERY. 
607 
Posterior Tibial Artery [Fig. 405, p. 604], 
The Posterior Tibial Artery is of large size, and extends obliquely downward 
from the lower border of the Popliteus muscle, along the tibial side of the leg, to 
the fossa between the inner ankle and the heel, where it divides beneath the origin 
of the Abductor pollicis into the internal and external plantar arteries. [As Wyeth 
has shown, it is important to note that this bifurcation takes place at a point cor- 
responding to a line drawn from the point of the malleolus to the middle of the 
heel.] At its origin it lies opposite the interval between the tibia and fibula; as it 
descends it approaches the inner side of the leg, lying behind the tibia, and in the 
lower part of its course is situated midway between the inner malleolus and the tube- 
rosity of the os calcis. 
Relations.-It lies successively upon the Tibialis posticus, the Flexor longus 
digitorum, the tibia, and the back part of the ankle-joint. It is covered by the 
deep transverse fascia, which separates it above from the Gastrocnemius and Soleus 
muscles. In the lower third, where it is more superficial, it is covered only by the 
integument and fascia, and runs parallel with the inner border of the tendo Achil- 
lis. It is accompanied by two veins and by the posterior tibial nerve, which lies at 
first to the inner side of the artery, but soon crosses it, and is, in the greater part 
of its course, on its outer side. [See Rule, p. 562.] 
Plan of the Relations of the Posterior Tibial Artery. 
In Front. 
Tibialis posticus. 
Flexor longus digitorum. 
Tibia. 
Ankle-joint. 
Inner Side. 
Posterior tibial nerve, 
upper fourth. 
Posterior 
Tibial. 
Outer Side. 
Posterior tibial nerve, 
lower three-fourths. 
Behind. 
Integument and fascia. 
Gastrocnemius. 
Soleus. 
Deep transverse fascia. 
Posterior tibial nerve. 
Behind the inner ankle the tendons and blood-vessels are arranged m the fol- 
lowing order, from within outward [z. e. from the inner malleolus toward the heel] : 
First, the tendons of the Tibialis posticus and Flexor longus digitorum, lying in 
the same groove, behind the inner malleolus, the former being the most internal; 
external to these is the posterior tibial artery, having a vein on either side; and 
still more externally the posterior tibial nerve. About half an inch nearer the 
heel is the tendon of the Flexor longus pollicis. [The artery is therefore the mid- 
dle one of these five structures.] 
Peculiarities in Size.-The posterior tibial is not unfrequently smaller than usual, or 
absent, its place being supplied by a large peroneal artery, which passes inward at the lower 
end of the tibia, and either joins the small tibial artery or continues alone to the sole of the foot. 
Surgical Anatomy.-The application of a ligature to the posterior tibial may be required 
in cases of wound of the sole of the foot attended with great hemorrhage, when the vessel should 
be tied at the inner ankle. In cases of wound of the posterior tibial, it will be necessary to 
enlarge the opening so as to expose the vessel at the wounded point, excepting where the vessel 
is injured by a punctured wound from the front of the leg. In cases of aneurism from wound 
of the artery low down, the vessel should be tied in the middle of the leg. But in aneurism of 
the posterior tibial high up, it would be better to tie the femoral artery. 
To tie the posterior tibial artery at the ankle a semilunar incision should be made through 
the integument, about two inches and a half in length, midway between the heel and inner ankle, 
or a little nearer the latter. The subcutaneous cellular tissue having been divided, a strong and 608 
THE ARTERIES. 
dense fascia, the internal annular ligament, is exposed. This ligament is continuous above with 
the deep fascia of the leg, covers the vessels and nerves, and is intimately adherent to the sheaths 
of the tendons. This having been cautiously divided upon a director, the sheath of the vessels is 
exposed, and, being opened, the artery is seen with one of the venae comites on each side. The 
aneurism-needle should be passed round the vessel from the heel toward the ankle, in order to 
avoid the posterior tibial nerve, care being at the same time taken not to include the venae comites. 
The vessel may also be tied in the lower third of the leg by making an incision about three 
inches in length, parallel with the inner margin of the tendo Achillis. The internal saphenous 
vein being carefully avoided, the two layers of fascia must be divided upon a director, when the 
artery is exposed along the outer margin of the Flexor longus digitorum, with one of its venae 
comites on either side, and the nerve lying external to it. 
To tie the posterior tibial in- the middle of the leg is a very difficult operation, on account of 
the great depth of the vessel from the surface and its being covered by the Gastrocnemius and 
Soleus muscles. The patient being placed in the recumbent position, the injured limb should 
rest on its outer side, the knee being partially bent, and the foot extended, so as to relax the 
muscles of the calf. An incision about four inches in length should then be made through 
the integument, a finger's breadth behind the inner margin of the tibia, taking care to avoid 
the internal saphenous vein. The deep fascia having been divided, the margin of the Gastro- 
cnemius is exposed, and must be drawn aside, and the tibial attachment of the Soleus divided, a 
director being previously passed beneath it. The artery may now be feH pulsating beneath the 
deep fascia [i. e. the intermuscular fascia which separates the calf muscles from the deeper mus- 
cles of the leg] about an inch from the margin of the tibia. The fascia having been divided, and 
the limb placed in such a position as to relax the muscles of the calf as much as possible, the 
veins should be separated from the artery, and the aneurism-needle passed round the vessel from 
without inward, so as to avoid wounding the posterior tibial nerve. 
The branches of the posterior tibial artery are the 
Peroneal. 
Anterior Peroneal. 
Muscular. 
Nutrient. 
Communicating. 
Internal Calcanean. 
The Peroneal Artery lies deeply seated along the back part of the fibular side 
of the leg. It arises from the posterior tibial about 
an inch below the lower border of the Popliteus mus- 
cle, passes obliquely outward to the fibula, and then 
descends along the inner border of that bone, under 
cover or through the fibres of the Flexor longus pol- 
licis, to the lower third of the leg, where it gives off 
the anterior peroneal. It then passes across the ar- 
ticulation between the tibia and fibula to the outer 
side of the os calcis, supplying the neighboring mus- 
cles and back of the ankle, and anastomosing with 
the external malleolar, tarsal, and external plantar 
arteries. 
Relations.-This vessel rests at first upon the 
Tibialis posticus, and then for the greater part of its 
course on the interosseous membrane close to the bone, 
covered or surrounded by the fibres of the Flexor 
longus pollicis. It is covered in the upper part of 
its course by the Soleus and deep transverse fascia; below, by the Flexor longus 
pollicis. 
[Fig. 407. 
Relations of Parts behind the Inner 
Malleolus (from Hirschfeldt and Le- 
veill6): 1,1, Tibialis posticus; 2, Ten- 
do Achillis; 3, Tibialis anticus, 4, 4, 
Flexor longus digitorum; 6, poste- 
rior tibial artery; 8, posterior tibial 
nerve.-The tendon of the Flexor 
longus pollicis is too deeply placed 
to be shown in this view.] 
Plan of the Relations of the Peroneal Artery. 
In Front. 
Tibialis posticus. 
Interosseous membrane. 
Outer Side. 
Fibula. 
Flexor longus pollicis. 
Peroneal 
Artery. 
Inner Side. 
Flexor longus pollicis. 
Behind. 
Soleus. 
Deep transverse fascia. 
Flexor longus pollicis. POSTERIOR TIBIAL ARTERY. 
609 
Peculiarities in Origin.-The peroneal artery may arise three inches below the Popliteus, 
or from the posterior tibial high up, or even from the popliteal. 
Its size is more frequently increased than diminished; and then it either reinforces the pos- 
terior tibial by its junction with it, or altogether takes the place of the posterior tibial in the 
lower part of the leg and foot, the latter vessel only existing as a short muscular branch. In 
those rare cases where the peroneal artery is smaller than usual a branch from the posterior 
tibial supplies its place; and a branch from the anterior tibial compensates for the diminished 
anterior peroneal artery. In one case the peroneal artery has been found entirely wanting. 
The anterior peroneal is sometimes enlarged, and takes the place of the dorsal artery of the 
foot. 
The peroneal artery in its course gives off branches to the Soleus, Tibialis posti- 
cus, Flexor longus pollicis, and Peronei muscles, and a nutrient branch to the fibula. 
The anterior peroneal, the only named branch of the peroneal artery, pierces 
the interosseous membrane about two inches above the outer malleolus to reach the 
fore part of the leg, and, passing down beneath the Peroneus tertius to the outer 
ankle, ramifies on the front and outer side of the tarsus, anastomosing with the 
external malleolar and tarsal arteries. 
The nutrient artery of the tibia arises from the posterior tibial near its origin, 
and, after supplying a few muscular branches, enters the nutrient canal of that bone, 
which it traverses obliquely from above downward. This is the largest nutrient artery 
of bone in the body. 
The muscular branches of the posterior tibial are distributed to the Soleus and 
deep muscles along the back of the leg. 
The communicating branch to the peroneal runs transversely across the back 
Fig. 408. 
Fig. 409. 
Communicating 
Branch of -i 
DORSALIS PEDIS/ 
Its Digital 
Branches 
The Plantar Arteries, superficial view. 
The Plantar Arteries, deep view. 
of the tibia about two inches above its lower end, passing beneath the Flexor 
longus pollicis. 
The internal calcanean are several large arteries which arise from the posterior 
tibial just before its division; they are distributed to the fat and integument behind 
the tendo Achillis and about the heel, and to the muscles on the inner side of the 
sole, anastomosing with the peroneal and internal malleolar arteries. 610 
THE ARTERIES. 
The Internal Plantar Artery (Figs. 408, 409, p. 609), much smaller than the 
external, passes forward along the inner side of the foot. It is at first situated above1 
the Abductor pollicis, and then between it and the Flexor brevis digitorum, both of 
which it supplies. At the base of the first metatarsal bone, where it has become 
much diminished in size, it passes along the inner border of the great toe, inoscu- 
lating with its digital branch. 
The External Plantar Artery, much larger than the internal, passes obliquely 
outward and forward to the base of the fifth metatarsal bone. It then turns 
obliquely inward to the interval between the bases of the first and second meta- 
tarsal bones, where it anastomoses with the communicating branch from the dorsalis 
pedis artery, thus completing the plantar arch. As this artery passes outward, it 
is first placed betw'een the os calcis and Abductor pollicis, and then between the 
Flexor brevis digitorum and Flexor accessorius; and as it passes forward to the 
base of the little toe, it lies more superficially between the Flexor brevis digitorum 
and Abductor minimi digiti, covered by the deep fascia and integument. The 
remaining portion of the vessel is deeply situated; it extends from the base of the 
metatarsal bone of the little toe to the back part of the first interosseous space, and 
forms the plantar arch ; it is convex forward, lies upon the Interossei muscles oppo- 
site the tarsal ends of the metatarsal bones, and is covered by the Adductor pollicis, 
the Flexor tendons of the toes, and the Lumbricales. 
Branches.-The plantar arch, besides distributing numerous branches to the 
muscles, integument, and fascise in the sole, gives off the following branches: 
Posterior Perforating. 
Digital-Anterior Perforating. 
The posterior perforating are three small branches which ascend throng]i the 
back part of the three outer interosseous spaces, between the heads of the Dorsal 
interossei muscles, and anastomose with the interosseous branches from the meta- 
tarsal artery. 
The digital branches are four in number, and supply the three outer toes and 
half the second toe. The first passes outward from the outer side of the plantar 
arch, and is distributed to the outer side of the little toe, passing in its course 
beneath the Abductor and short Flexor muscles. The second, third, and fourth 
run forward along the interosseous spaces, and on arriving at the clefts between the 
toes divide into collateral branches which supply the adjacent sides of the three 
outer toes and the outer side of the second. At the bifurcation of the toes each 
digital artery sends upward, through the fore part of the corresponding metatarsal 
space, a small branch which inosculates with the interosseous branches of the meta- 
tarsal artery. These are the anterior perforating branches. 
From the arrangement already described of the distribution of the vessels to the 
toes, it will be seen that both sides of the three outer toes and the outer side of the 
second toe are supplied by branches from the plantar arch, both sides of the great 
toe and the inner side of the second being supplied by the communicating branch 
of the dorsalis pedis. 
1 This refers to the erect position of the body. In the ordinary [position for] dissection the artery 
is deeper than the muscle. Of the Veins. 
THE Veins are the vessels which serve to return the hlood from the capillaries 
of the different parts of the body to the heart. They consist of two distinct 
sets of vessels, the pulmonary and systemic. 
Pulmonary Veins, unlike other vessels of this kind, contain arterial blood, 
which they return from the lungs to the left auricle of the heart. 
The Systemic Veins return the venous blood from the body generally to the 
right auricle of the heart. 
The Portal Vein, an appendage to the systemic venous system, is confined to 
the abdominal cavity, returning the venous blood from the viscera of digestion, 
and carrying it to the liver by a single trunk of large size, the vena portce. This 
vessel ramifies in the substance of the liver and breaks up into a minute network 
of capillaries. These capillaries then reunite to form the hepatic veins, by which 
the blood is conveyed to the inferior vena cava. 
The veins, like the arteries, are found in nearly every tissue of the body. They 
commence by minute plexuses which receive the blood from the capillaries. The 
branches which have their commencement in these plexuses unite together into 
trunks, and these in their passage toward the heart constantly increase in size as 
they receive tributaries and join other veins similar in size to themselves. The 
veins are larger and altogether more numerous than the arteries; hence the entire 
capacity of the venous system is much greater than that of the arterial, the pul- 
monary veins excepted, which do not exceed in capacity the pulmonary arteries. 
From the combined area of the smaller venous branches being greater than the 
main trunks, it results that the venous system represents a cone, the summit of 
which corresponds to the heart, its base to the circumference of the body. In 
form, the veins are not perfectly cylindrical like the arteries, their walls being 
collapsed when empty, and the uniformity of their surface being interrupted at 
intervals by slight contractions, which indicate the existence of valves in their 
interior. They usually retain, however, the same calibre as long as they receive 
no branches. 
The veins communicate very freely with one another, especially in certain regions 
of the body; and this communication exists between the larger trunks as well as 
between the smaller branches. Thus in the cavity of the cranium and between the 
veins of the neck, where obstruction would be attended with imminent danger to 
the cerebral venous system, we find that the sinuses and larger veins have large 
and very frequent anastomoses. The same free communication exists between the 
veins throughout the whole extent of the spinal canal, and between the veins com- 
posing the various venous plexuses in the abdomen and pelvis, as the spermatic, 
uterine, vesical, prostatic, etc. 
The [systemic] veins are subdivided into three sets-superficial veins, deep veins, 
and sinuses. 
The Superficial or Subcutaneous Veins are found between the layers of the 
superficial fascia, immediately beneath the integument; they return the blood from 
these structures and communicate with the deep veins by perforating the deep 
fascia. 
The Deep Veins accompany the arteries, and are usually enclosed in the same 
sheath with those vessels. In the smaller arteries, as the radial, ulnar, brachial, 
tibial, peroneal, they exist generally in pairs, one lying on each side of the vessel, 
and are called vence comites [z. e. companion veins]. The larger arteries, as the 
axillary, subclavian, popliteal, and femoral, have usually only one accompanying 
611 612 
THE VEINS. 
vein. In certain organs of the body, however, the deep veins do not accompany 
the arteries; for instance, the veins in the skull and spinal canal, the hepatic veins 
in the liver, and the larger veins returning blood from the osseous tissue. 
Sinuses are venous channels which in their structure and mode of distribution 
differ altogether from the veins. They are found only in the interior of the skull, 
and are formed by a separation of the layers of the dura mater, their outer coat 
consisting of fibrous tissue, their inner of an endothelial layer continuous with the 
lining membrane of the veins. 
Veins have thinner walls than arteries, the difference in thickness being due to 
the small amount of elastic and muscular tissues which the veins contain. The 
superficial veins usually have thicker coats than the deep veins, and the veins of 
the lower limb are thicker than those of the upper. 
The minute structure of these vessels is described in the section on General 
Anatomy. 
The veins, like the arteries, consist of two separate and distinct systems: the 
pulmonary, which are concerned in the circulation of the lungs and convey arterial 
blood; and the systemic, which are concerned in the general circulation and convey 
venous blood.1 
THE PULMONARY VEINS. 
The Pulmonary Veins return the arterial blood from the lungs to the left auricle 
of the heart. They are four in number, two for each lung. The pulmonary differ 
from other veins in several respects: 1, they carry arterial instead of venous blood; 
2, they are destitute of valves ; 3, they are only slightly larger than the arteries they 
accompany; 4, they accompany those vessels singly. They commence in a capil- 
lary network upon the walls of the air-cells, where they are continuous with the 
ramifications of the pulmonary artery, and, uniting together, form a single trunk 
for each lobule. These branches, uniting successively, form a single trunk for each 
lobe, three for the right and two for the left lung. The vein from the middle lobe 
of the right lung unites with that from the upper lobe, in most cases forming two 
trunks on each side, which open separately into the left auricle. Occasionally they 
remain separate; there are then three veins on the right side. Not unfrequently 
the two left pulmonary veins terminate by a common opening. 
Within the lung the branches of the pulmonary artery are in front, the veins 
behind, and the bronchi between the two. 
At the root of the lung the veins are in front, the artery in the middle, and the 
bronchus behind. 
Within the pericardium their anterior surface is invested by the serous layer 
of this membrane. The right pulmonary veins pass behind the right auricle and 
ascending aorta; the left pass in front of the thoracic aorta with the left pulmonary 
artery. 
THE SYSTEMIC VEINS. 
The Systemic Veins may be arranged into three groups: 1, those of the head 
and neck, upper extremity, and thorax, which terminate in the superior vena cava; 
2, those of the lower limb, pelvis, and abdomen, which terminate in the inferior 
vena cava; 3, the cardiac veins, which open directly into the right auricle of the 
heart. 
Veins of the Head and Neck. 
The veins of the head and neck may be subdivided into three groups; 1, the 
veins of the exterior of the head; 2, the veins of the neck ; 3, the veins of the 
diploe and interior of the cranium. 
1 [For the anomalies of the veins see Krause in Henle's Anatomie, Braunschweig, 1876, vol. iii. 
p. 395.] VEINS OF THE HEAD AND NECK. 
613 
The veins of the exterior of the head are the 
Facial. 
Temporal. 
Internal Maxillary. 
Temporo-maxillary. 
Posterior Auricular. 
Occipital. 
The Facial Vein passes obliquely across the side of the face, extending from the 
inner angle of the orbit downward and outward to the anterior margin of the Masse- 
ter muscle. It lies to the outer side of the facial artery, and is not so tortuous as 
Fro. 410. 
Frontal 
Cornmu/rucatinu 
~ Branch wifK 
Ophthalmic Vein 
-Angular 
Laryngeal 
Superior Thyroid 
Veins of the Head and Neck. 
that vessel. It commences at the side of the root of the nose, and is the direct con- 
tinuation of the angular vein, formed by the junction of the frontal and supraorbital 
veins. 
The frontal vein commences on the anterior part of the skull by a venous plexus 
which communicates with the anterior tributaries of the temporal vein ; the veins 
converge to form a single trunk, which runs downward near the middle line of the 
forehead parallel with the vein of the opposite side, and unites with it at the root 
of the nose by a transverse trunk, called the nasal arch. Occasionally the frontal 614 
THE VEINS. 
veins join to form a single trunk, which bifurcates at the root of the nose into the 
two angular veins. At the nasal arch the branches diverge and run along the sides 
of the root of the nose. The frontal vein as it descends upon the forehead receives 
the supraorbital and becomes the angular vein. 
The supraorbital vein commences on the forehead, communicating with the 
anterior temporal and superior palpebral veins, and runs downward and inward 
beneath the Occipito-frontalis muscle, receiving tributaries from the neighboring 
structures, and joins the frontal vein at the inner angle of the orbit to form the 
angular vein. 
The angular vein, formed by the junction of the two preceding vessels, runs 
obliquely downward and outward on the side of the root of the nose, and receives 
the veins of the ala nasi on its inner side and the superior palpebral veins on its 
outer side; it moreover communicates with the ophthalmic vein, which establishes 
an important anastomosis between this vessel and the cavernous sinus. Some 
small veins from the dorsum of the nose terminate in the nasal arch. 
The facial vein commences at the inner angle of the orbit, being a continua- 
tion of the angular vein. It passes obliquely downward and outward beneath the 
Zygomaticus major and minor muscles, descends along the anterior border of the 
Masseter, crosses over the body of the lower jaw with the facial artery, and, pass- 
ing obliquely outward and backward beneath the Platysma and cervical fascia, 
unites with a branch of communication from the temporo-maxillary vein to form a 
trunk of large size which enters the internal jugular. From near its termination a 
communicating branch often runs down the anterior border of the Sterno-mastoid to 
join the lower part of the anterior jugular. 
Tributaries.-The facial vein receives, near the angle of the mouth, commu- 
nicating tributaries of considerable size (the deep facial or anterior internal maxil- 
lary vein) from the pterygoid plexus. It is also joined by the inferior palpebral, 
the superior and inferior labial veins, the buccal veins from the cheek, and the 
masseteric veins. Below the jaw it receives the submental, the inferior palatine, 
which returns the blood from the plexus around the tonsil and soft palate, the sub- 
maxillary vein, which commences in the submaxillary gland, and generally the 
ranine vein. 
The Temporal Vein commences by a minute plexus on the side and vertex of 
the skull, which communicates with the frontal vein in front, the corresponding 
vein of the opposite side, and the posterior auricular and occipital veins behind. 
From this network anterior and posterior branches are formed which unite above 
the zygoma, forming the trunk of the vein. This trunk is joined in this situation 
by a large vein, the middle temporal, which receives the blood from the substance 
of the Temporal muscle and pierces the fascia at the upper border of the zygoma. 
The temporal vein then descends between the external auditory meatus and the 
condyle of the jaw, enters the substance of the parotid gland, and unites with the 
internal maxillary vein to form the temporo-maxillary trunk. 
Tributaries.-The temporal vein receives in its course some parotid veins, an 
articular branch from the articulation of the jaw, anterior auricular veins from the 
external ear, and a vein of large size, the transverse facial, from the side of the face. 
The Internal Maxillary Vein is a vessel of considerable size, receiving branches 
which correspond with those of the internal maxillary artery. Thus it receives 
the middle meningeal veins, the deep temporal, the pterygoid, masseteric, buccal, 
alveolar, some palatine veins, and the inferior dental. These branches form a large 
plexus, the pterygoid, which is placed between the Temporal and External ptery- 
goid, and partly between the Pterygoid muscles. This plexus communicates very 
freely with the facial vein and with the cavernous sinus by branches through the 
foramen Vesalii at the base of the skull. The trunk of the vein then passes back- 
ward behind the neck of the lower jaw, and unites with the temporal vein, forming 
the temporo-maxillary-trunk. 
The Temporo-maxillary Vein, formed by the union of the temporal and inter- 
nal maxillary veins, descends in the substance of the parotid gland on the outer VEINS OF THE NECK. 
615 
surface of the external carotid artery, between the ramus of the jaw and the Ster- 
no-mastoid muscle, and divides into two branches, one of which passes inward to 
join the facial vein; the other is joined by the posterior auricular vein and becomes 
the external jugular. 
The Posterior Auricular Vein commences upon the side of the head by a plexus 
which communicates with the tributaries of the temporal and occipital veins. The 
vein descends behind the external ear and joins the temporo-maxillary vein, form- 
ing the external jugular. This vessel receives the stylo-mastoid vein and some tribu- 
taries from the back part of the external ear. 
The Occipital Veins, generally two or three in number, commence at the back 
part of the vertex of the skull by a plexus, in a similar manner to the other veins. 
It follows the course of the occipital artery, passing deeply beneath the muscles of 
the back part of the neck, and terminates in the internal jugular, occasionally in 
the external jugular. As this vein passes across the mastoid portion of the tem- 
poral bone it receives the mastoid vein, which establishes a communication with the 
lateral sinus. 
Veins of the Neck. 
The veins of the neck, which return the blood from the head and face, are the 
External Jugular. 
Posterior External Jugular. 
Anterior Jugular. 
Internal Jugular. 
Vertebral. 
The External Jugular Vein receives the greater part of the blood from the 
exterior of the cranium and deep parts of the face, being formed by the junction of 
the posterior division of the temporo-maxillary and posterior auricular veins. It 
commences in the substance of the parotid gland on a level with the angle of the 
lower jaw, and runs perpendicularly down the neck in the direction of a line drawn 
from the angle of the jaw to the middle of the clavicle. In its course it crosses the 
Sterno-mastoid muscle, and runs parallel with its posterior border as far as its attach- 
ment to the clavicle, where it perforates the deep fascia, and terminates in the subcla- 
vian vein, on the outer side of or in front of the Scalenus anticus muscle. [Pressure 
at this point will generally make this vein quite manifest by interrupting the return- 
ing blood-current, and so dilating the vein. Its position should always be deter- 
mined before beginning operations in the neck.] In the neck it is separated from 
tho Sterno-mastoid by the anterior layer of the deep cervical fascia, and is covered 
by the Platysma, the superficial fascia, and the integument. This vein is crossed 
about its middle by the superficial cervical nerve, and its upper half is accompanied 
by the auricularis magnus nerve. The external jugular vein varies in size, bear- 
ing an inverse proportion to that of the other veins of the neck ; it is occasionally 
double. It is provided with two pairs of valves, the lower pair being placed at its 
entrance into the subclavian vein, the upper pair in most cases about an inch and a 
half above the clavicle. The portion of vein between the two sets of valves is 
often dilated, and is termed the sinus. These valves do not prevent the regurgi- 
tation of the blood or the passage of injection from below upward.1 
Tributaries.-This vein receives tbe occipital occasionally, the posterior exter- 
nal jugular, and near its termination the suprascapular and transverse cervical veins. 
It communicates with the anterior jugular, and in the substance of the parotid 
receives a large branch of communication from the internal jugular. 
The,Posterior External Jugular Vein returns the blood from the integument 
and superficial muscles in the upper and back part of the neck lying between the 
Splenius and Trapezius muscles. It runs down the back part of the neck, and 
opens into the external jugular just below the middle of its course. 
The Anterior Jugular Vein commences near the hyoid bone from the con- 
1 The student may refer to an interesting paper by Dr. Struthers, "On Jugular Venesection in 
Asphyxia, Anatomically and Experimentally Considered, including the Demonstration of Valves in 
the Veins'of the Neck," in the Edinburgh Medical Journal for November, 1856. 616 
THE VEINS. 
vergence of several superficial veins from the submaxillary region. It passes down 
between the median line and the anterior border of the Sterno-mastoid, and at the 
lower part of the neck passes beneath that muscle to open into the termination of 
the external jugular or into the subclavian vein (Fig. 417). This vein varies con- 
siderably in size, bearing almost always an inverse proportion to the external jugu- 
lar. Most frequently there are two anterior jugulars, a right and left, but occa- 
sionally only one. This vein receives some laryngeal veins, and occasionally an 
inferior thyroid vein. Just above the sternum the two anterior jugular veins com- 
municate by a transverse trunk which receives tributaries from the inferior thyroid 
veins. It also communicates with the internal jugular. There are no valves in 
this vein. [The position of this vein also is important in operations in the neck, 
and should be ascertained by inspection and pressure.] 
The Internal Jugular Vein collects the blood from the interior of the cranium, 
from the superficial parts of the face, and from the neck. It commences just exter- 
nal to the jugular foramen in the base of the skull, being formed by the coalescence 
of the lateral and inferior petrosal sinuses (Fig. 415). At its origin it is somewhat 
dilated, and this dilatation is called the sinus (or gulf) of the internal jugular vein. 
It runs down the side of the neck in a vertical direction, lying at first on the outer 
side of the internal carotid, and then on the outer side of the common carotid, and 
at the root of the neck unites with the subclavian vein to form the vena innominata. 
The internal jugular vein at its commencement lies upon the Rectus lateralis behind, 
and at the outer side of the internal carotid and the nerves passing through the jug- 
ular foramen; lower down the vein and artery lie upon the same plane, the glosso- 
pharyngeal and hypoglossal nerves passing forward between them; the pneumogas- 
tric descends between and behind them in the same sheath, and the spinal accessory 
passes obliquely outward behind the vein. At the root of the neck the vein of the 
right side is placed at a little distance from the artery; on the left side it usually 
lies over the artery at its lower part. The right internal jugular vein crosses the 
first part of the subclavian artery. The vein is of considerable size, but varies in 
different individuals, the left one being usually the smaller. It is provided with a 
pair of valves which are placed at its point of termination, or from one-half to three- 
quarters of an inch above it. 
Tributaries.-This vein receives in its course the facial, lingual, pharyngeal, 
superior and middle thyroid veins, and sometimes the occipital. At its point of 
junction with the branch common to the temporal and facial veins it becomes 
greatly increased in size. 
The lingual veins commence on the dorsum, sides, and under surface of the 
tongue, and, passing backward, following the course of the lingual artery and its 
branches, terminate in the internal jugular. Sometimes the ranine vein, which is 
a branch of considerable size commencing below the tip of the tongue, joins the 
lingual. Generally, however, it passes backward, crosses the Hyo-glossus muscle in 
company with the hypoglossal nerve, and joins the facial. 
The pharyngeal vein commences in a minute plexus, the pharyngeal, at the 
back part and sides of the pharynx, and after receiving meningeal tributaries and 
the Vidian and spheno-palatine veins terminates in the internal jugular. It occa- 
sionally opens into the facial, lingual, or superior thyroid vein. 
The superior thyroid vein commences in the substance and on the surface of 
the thyroid gland by tributaries corresponding with the branches of the superior 
thyroid artery, and terminates in the upper part of the internal jugular vein. 
The middle thyroid vein collects the blood from the lower part of the lateral 
lobe of the thyroid gland, and, being joined by some veins from the larynx and 
trachea, terminates in the lower part of the internal jugular vein. 
The facial and occipital veins have been described above. 
The Vertebral Vein commences in the occipital region by numerous small trib- 
utaries from the deep muscles at the upper and back part of the neck, passes out- 
ward and enters the foramen in the transverse process of the atlas, and descends by 
the side of the vertebral artery in the canal formed by the transverse processes of VEINS OF THE DIPLOE. 
617 
the cervical vertebrae. Emerging from the foramen in the transverse process of the 
sixth cervical, it terminates at the root of the neck in the back part of the innom- 
inate vein near its origin, its mouth being guarded by a pair of valves. On the 
right side it crosses the first part of the subclavian artery. This vein in the lower 
part of its course occasionally divides into two branches, one of which emerges with 
the artery at the sixth cervical vertebra: the other escapes through the foramen in 
the seventh cervical. 
Tributaries.-The vertebral vein receives in its course a vein from the inside 
of the skull through the posterior condyloid foramen; muscular veins from the 
muscles in the prevertebral region; dorsi-spinal veins from the back part of the 
cervical portion of the spine; meningo-rachidian veins from the interior of the 
spinal canal; the ascending and deep cervical veins; and close to its termination 
it is joined by a small vein from the first intercostal space, which accompanies the 
superior intercostal artery. [It will be noticed that the vertebral vein drains a 
very different region from that which is supplied by its corresponding artery.] 
The ascending1 cervical vein (anterior vertebral) commences in a plexus 
around the transverse processes of the upper cervical vertebrae, descends in com- 
pany with the ascending cervical artery between the Scalenus anticus and Rectus 
capitis anticus major muscles, and opens into the vertebral vein just before its 
termination. 
The deep cervical vein (posterior vertebral) accompanies the profunda cer- 
vicis artery, lying between the Complexus and Semispinalis colli. It commences 
in the suboccipital region by communicating branches from the occipital vein and 
tributaries from the deep muscles at the back of the neck. It receives tributaries 
from the plexuses around the spinous processes of the cervical vertebrae, and termi- 
nates in the lower end of the vertebral vein. 
Veins of the Diploe. 
The diploe of the cranial bones is channelled in the adult by a number of tortu- 
ous canals which are lined by a more or less complete layer of compact tissue. 
Fig. 411. 
The veins they contain are large and capacious, their walls being thin and formed 
only of epithelium, resting upon a layer of elastic tissue, and they present at irreg- 
Veins of the Diploe, as displayed by the removal of the outer table of the skull. 618 
THE VEINS. 
ular intervals pouch-like dilatations, or culs-de-sac, which serve as reservoirs for the 
blood. These are the veins of the diploe : they can only be displayed by removing 
the outer table of the skull. 
In adult life, as long as the cranial bones are distinct and separable, these veins are 
confined to the particular bones; but in old age, when the sutures are united, they 
communicate with each other and increase in size. These vessels communicate in 
the interior of the cranium with the meningeal veins and with the sinuses of the 
dura mater, and on the exterior of the skull with the veins of the pericranium. They 
are divided into the frontal, which opens into the supraorbital vein by an aperture 
at the supraorbital notch ; the anterior temporal, which is confined chiefly to the 
frontal bone and opens into one of the deep temporal veins after escaping by an 
aperture in the great wing of the sphenoid; the posterior temporal, which is con- 
fined to the parietal bone and terminates in the lateral sinus by an aperture at the 
posterior inferior angle of the parietal bone; and the occipital, the largest of the 
four, which is confined to the occipital bone and opens either into the occipital vein 
or internally into the lateral sinus or the torcular Herophili. 
Cerebral Veins. 
The Cerebral Veins are remarkable for the extreme thinness of their coats, in 
consequence of the muscular tissue in them being wanting, and for the absence of 
valves. They may be divided into two sets-the superficial, which are placed on the 
surface; and the deep veins, which occupy the interior of the organ. 
The Superficial Cerebral Veins ramify upon the surface of the brain, being 
lodged in the sulci between the convolutions, a few running across the convolutions. 
They receive branches from the substance of the brain and terminate in the sinuses. 
They are named, from the position they occupy, superior and inferior. 
The Superior Cerebral Veins, eight to twelve in number on each side, pass for- 
ward and inward toward the great longitudinal fissure, where they receive the inter- 
nal cerebral veins, which return the blood from the convolutions of the mesial sur- 
face of the corresponding hemisphere; near their termination they become invested 
with a tubular sheath of the arachnoid membrane, and open into the superior longi- 
tudinal sinus in the opposite direction to the course of the blood. The external 
cerebral veins, which return the blood from the convolutions on the outer surface of 
the hemisphere, also open, for the most part, into these veins. 
The Inferior Cerebral Veins ramify on the outer and under surface of the cere- 
bral hemisphere, and pass inward to the cavernous, superior petrosal, and lateral 
sinuses. Some, collecting tributaries from the under surface of the anterior lobes 
of the brain, terminate in the cavernous sinus. One vein of large size, the middle 
cerebral vein, commences on the under surface of the temporo-sphenoidal lobe, and, 
running along the fissure of Sylvius, opens into the cavernous sinus. Another large 
vein, the great anastomotic vein of Trolard, commences on the parietal lobe, runs 
along the horizontal limb of the fissure of Sylvius, and opens into the superior 
petrosal sinus. Others commence on the under surface of the base of the brain, and 
unite to form from three to five veins which open into the lateral sinus from before 
backward. 
The Deep Cerebral or Ventricular Veins (venae G-aleni) [Fig. 412] are two 
in number. They are formed by the union of two veins, the vena corporis striati 
and the choroid vein on either side. They run backward, parallel with one another, 
between the layers of the velum interpositum, and pass out of the brain at the great 
transverse fissure between the posterior extremity, or splenium, of the corpus cal- 
losum and the tubercula quadrigemina, to enter the straight sinus. The two veins 
usually unite to form one before opening into the straight sinus. 
The Vena Corporis Striati commences in the groove between the corpus stria- 
tum and thalamus opticus, receives numerous veins from both of these parts, and 
unites behind the anterior pillar of the fornix with the choroid vein to form one of 
the venae Galeni. SINUSES OF THE DURA MATER. 
619 
The Choroid Vein runs along the whole length of the outer border of the cho- 
roid plexus, receiving veins from the hippocampus major, the fornix, and corpus 
callosum, and unites at the anterior extremity of the choroid plexus with the vein 
of the corpus striatum. 
The Cerebellar Veins occupy the surface of the cerebellum, and are disposed in 
three sets-superior, inferior, and lateral. The superior pass forward and inward 
across the superior vermiform process, and terminate in the straight sinus; some 
open into the venae Galeni. The inferior cerebellar veins, of large size, run trans- 
versely outward, and terminate by two or three trunks in the lateral sinuses. The 
lateral anterior cerebellar veins terminate in the superior petrosal sinuses. 
Sinuses of the Dura Mater [Figs. 412, 414]. 
The sinuses of the dura mater are venous channels analogous to the veins, theii 
outer coat being formed by the dura mater; their inner, by a continuation of the 
Fig. 412. 
-Foramen Ccceun 
1\>T0Ular_ 
Hcrophili 
Vertical Section of the Skull, showing the Sinuses of the Dura Mater. 
lining membrane of the veins. They are fifteen in number, and are divided into 
two sets: 1, those situated at the upper and back part of the skull; 2, those at the 
base of the skull. The former are the 
Superior Longitudinal. 
Inferior Longitudinal. 
Straight Sinus. 
Lateral Sinuses. 
Occipital Sinus. 
The Superior Longitudinal Sinus occupies the attached margin of the falx 
cerehri. Commencing at the foramen caecum, through which it constantly com- 
municates by a small branch with the veins of the nasal fossae, it runs from before 
backward, grooving the inner surface of the frontal, the adjacent margins of the 
two parietal, and the superior division of the crucial ridge of the occipital bone, and 
terminates by opening into the torcular Herophili. The sinus is triangular in form, 
narrow in front, and gradually increasing in size as it passes backward. On exam- 
ining its inner surface it presents the internal openings of the cerebral veins, which 
run, for the most part, from behind forward, and open chiefly at the back part of 
the sinus, their orifices being concealed by fibrous folds; numerous fibrous bands 
(chordce Willisii) are also seen, which extend transversely across the inferior angle 
of the sinus; and lastly, some small, white, projecting bodies, the glandules Pac- 
chioni. This sinus receives the superior cerebral veins, numerous veins from the 
diploe and dura mater, and at the posterior extremity of the sagittal suture veins 
from the pericranium, which pass through the parietal foramen. 620 
THE VEINS. 
The torcular Herophili is the dilated extremity of the superior longitudinal sinus. 
It is of irregular form, and is lodged on one side (generally the right) of the internal 
occipital protuberance. From it the lateral sinus of the side to which it is deflected 
is derived. It receives also the blood from the occipital sinus. 
The Inferior Longitudinal Sinus, more correctly described as the inferior longi- 
tudinal vein, is contained in the posterior part of the free margin of the falx cerebri. 
It is of a cylindrical form, increases in size as it passes backward, and terminates in 
the straight sinus. It receives several veins from the falx cerebri, and occasionally 
a few from the mesial surface of the hemispheres. 
The Straight Sinus [Sinus rectus] is situated at the line of junction of the 
falx cerebri with the tentorium. It is triangular in form, increases in size as it pro- 
ceeds backward, and runs obliquely downward and backward from the termination 
of the inferior longitudinal sinus to the lateral sinus of the opposite side to that into 
which the superior longitudinal sinus is prolonged. It communicates by a consider- 
able opening with the torcular Herophili. Besides the inferior longitudinal sinus it 
receives the venae Galeni and the superior cerebellar. A few transverse bands cross 
its interior. 
The Lateral Sinuses are of large size, and are situated in the attached margin 
of the tentorium cerebelli. They commence at the internal occipital protuberance, 
the one, generally the right, being the direct continuation of the superior longitu- 
dinal sinus, the other of the straight sinus. They pass horizontally outward to the 
base of the petrous portion of the temporal bone; then curve downward and inward 
on each side to reach the jugular foramen, where they terminate in the internal jug- 
ular vein. Each sinus rests in its course upon the inner surface of the occipital, the 
posterior inferior angle of the parietal, the mastoid portion of the temporal, and on 
the occipital again just before its termination. These sinuses are frequently of 
unequal size, that formed by the superior longitudinal sinus being the larger, and 
they increase in size as they proceed from behind forward. The horizontal portion 
is of a triangular form, the curved portion semi-cylindrical; their inner surface is 
smooth, and not crossed by the fibrous bands found in the other sinuses. These 
sinuses receive the blood from the superior petrosal sinuses at the base of the 
petrous portion of the temporal bone, and they unite with the inferior petrosal 
sinus, just external to the jugular foramen, to form the internal jugular vein (Fig. 
415). They communicate with the veins of the pericranium by means of the mas- 
toid and posterior condyloid veins, and they receive some of the inferior cerebral 
and inferior cerebellar veins, and some veins from the diploe. 
The Occipital is the smallest of the cranial sinuses. It is generally single, but 
occasionally there are two. It is situated in the attached margin of the falx ccre- 
belli. It commences by several small veins around the margin of the foramen mag- 
num, one of which joins the termination of the lateral sinus; it communicates with 
the posterior spinal veins, and terminates in the torcular Herophili.1 
The sinuses at the base of the skull are the 
Cavernous. 
Circular. 
Inferior Petrosal. 
Superior Petrosal. 
Transverse. 
1 I am indebted to Mr. Ross, demonstrator of anatomy at St. George's Hospital, for the following 
note on the torcular Herophili and the sinuses converging to it. He examined them in ten subjects, 
and reports as follows: 
1. In all there was a free communication between the opposite lateral sinuses. 
2. The superior longitudinal sinus terminated in seven cases in the right lateral sinus; in two in 
the left lateral sinus; and in one case it divided, the right portion being much the larger. 
3. The straight sinus terminated in four cases in the middle line-i. e. over the internal occipital 
protuberance: in three cases it divided, part going to the right and part to the left lateral sinus; in 
two cases it terminated in the left lateral sinus, and in one case in the right lateral sinus. 
4. The occipital sinus terminated in nine cases in the middle line ; in these cases it was most fre- 
quently single. 
5. That lateral sinus in which the superior longitudinal sinus terminated was usually the larger 
of the two-in one or two cases twice the size of the other. SINUSES OF THE DURA MATER. 
621 
The Cavernous Sinuses are named from their presenting a reticulated structure. 
They are two in number, of large size, and placed one on each side of the sella Tur- 
cica, extending from the sphenoidal fissure to the apex of the petrous portion of the 
Fig. 413. 
.LINING MEMBRANE OF SINUS 
dura mater 
lining pituitary 
FOSSA 
,3& NERVE 
NERVE 
6 NERVE- 
ls-T DIVISION OF 5t-h NERVE 
INTERNAL CAROTID 
Plan showing the Relative Position of the Structures in the Right Cavernous Sinus, viewed from behind. 
temporal bone; they receive anteriorly the ophthalmic vein through the sphenoidal 
fissure, and communicate behind with the petrosal sinuses and with each other by 
the circular and transverse sinuses. On the inner wall of each sinus is found the 
internal carotid artery, accompanied by filaments of the carotid plexus and by the 
sixth nerve; and on its outer 
wall, the third, fourth, and oph- 
thalmic nerves. These parts are 
separated from the blood flowing 
along the sinus by the lining 
membrane, which is continuous 
with the inner coat of the veins. 
The cavity of the sinus, which 
is larger behind than in front, 
is intersected by filaments of 
fibrous tissue and small vessels. 
The cavernous sinuses receive 
some of the cerebral veins; they 
communicate with the lateral 
sinuses by means of the supe- 
rior and inferior petrosal, and 
with the facial vein through the 
ophthalmic. They also commu- 
nicate with each other by means 
of the circular sinus. 
The Ophthalmic is a large 
vein which connects the angular 
vein at the inner angle of the 
orbit with the cavernous sinus ; 
it pursues the same course as 
the ophthalmic artery, and re- 
ceives tributaries corresponding 
to the branches derived from that vessel. Forming a short single trunk, it passes 
through the inner extremity of the sphenoidal fissure and terminates in the cavern- 
ous sinus. Sometimes the veins from the floor of the orbit collect into a separate 
trunk, the inferior ophthalmic vein, which either passes out of the orbit through the 
spheno-maxillary fissure to join the pterygoid plexus, or else, passing backward 
through the sphenoidal fissure, it enters the cavernous sinus, either by a separate 
opening or in common with the ophthalmic vein. 
The Circular Sinus is formed by two transverse vessels which connect together 
the two cavernous sinuses, the one passing in front and the other behind the pitu- 
itary body, and thus forming with the cavernous sinuses a venous circle around the 
Fig. 414. 
Opening of 
JMa staid Vein 
The Sinuses at the Base of the Skull. 622 
THE VEINS. 
body. The anterior one is usually the larger of the two, and one or other is occa- 
sionally found to be absent. 
The Inferior Petrosal Sinus is situated in the groove formed by the junction 
of the posterior border of the petrous portion of the temporal with the basilar pro- 
cess of the occipital. It commences in front at the termination of the cavernous 
sinus, and behind joins the lateral sinus external to the jugular foramen, forming 
the internal jugular vein. 
The junction of the two sinuses takes place at the lower border of, or just exter- 
nal to, the jugular foramen. The exact relation of the parts to one another in the 
Fig. 415. 
Relation of Structures in Jugular Foramen. 
foramen is as follows: The inferior petrosal sinus is in front, and is directed obliquely 
downward and backward; the lateral sinus is situated at the back part of the fora- 
men, and between the two are the glosso-pharyngeal, pneumogastric, and spinal 
accessory nerves. The junction of the sinuses takes place superficial to the nerves, 
so that these latter lie a little internal to the venous channels in the foramen. (See 
Fig. 415.) These sinuses are semi-cylindrical in form. 
The Transverse Sinus or Basilar Sinus consists of several interlacing veins 
between the layers of the dura mater over the basilar process of the occipital bone, 
which serve to connect the two inferior petrosal and cavernous sinuses. With them 
the anterior spinal veins communicate. 
The Superior Petrosal Sinus is situated along the superior border of the petrous 
portion of the temporal bone in the front part of the attached margin of the ten- 
torium. It is small and narrow, and connects together the cavernous and lateral 
sinuses at each side. It receives a cerebellar vein (anterior lateral cerebellar) from 
the anterior border of the cerebellum, a vein from the internal ear, and sometimes 
a cerebral vein (great anastomotic vein of Trolard) from the under part of the 
middle lobe. VEINS OF THE UPPER EXTREMITY. 
623 
VEINS OF THE UPPER EXTREMITY. 
The veins of the upper extremity are divided into two sets, superficial and deep. 
The Superficial Veins are placed immediately beneath the integument between 
the two layers of superficial fascia; they 
commence in the hand chiefly on its dorsal 
aspect, where they form a more or less com- 
plete arch. 
The Deep Veins accompany the arte- 
ries, and constitute the venae comites of 
those vessels. 
Both sets of vessels are provided with 
valves, which are more numerous in the 
deep than in the superficial. 
The superficial veins of the upper extrem- 
ity are the 
Fig. 416. 
Anterior Ulnar. 
Posterior Ulnar. 
Common Ulnar. 
Radial. 
Median. 
Median Basilic. 
Median Cephalic. 
Basilic. 
Cephalic. 
The Anterior Ulnar Vein commences 
on the anterior surface of the ulnar side of 
the hand and wrist, and ascends along the 
inner side of the forearm to the bend of the 
elbow, where it joins with the posterior ulnar 
vein to form the common ulnar. Occasion- 
ally it opens separately into the median basi- 
lic vein. It communicates with branches of 
the median vein in front and with the pos- 
terior ulnar behind. 
The Posterior Ulnar Vein commences 
on the posterior surface of the ulnar side of 
the hand and from the vein of the little fin- 
ger (vena salvateUa} situated over the fourth 
metacarpal space. It runs on the posterior 
surface of the ulnar side of the forearm, and 
just below the elbow unites with the ante- 
rior ulnar vein to form the common ulnar, 
or else joins the median basilic to form the 
basilic. It communicates with the deep veins 
of the palm by a branch which emerges from 
beneath the Abductor minimi digiti muscle. 
The Common Ulnar is a short trunk 
which is not constant. When it exists it is 
formed by the junction of the two preceding 
veins, and, passing upward and outward, 
joins the median basilic to form the basilic 
vein. When it does not exist the anterior 
and posterior ulnar veins open separately 
into the median basilic vein. 
The Radial Vein commences from the 
dorsal surface of the thumb, index finger, 
and radial side of the hand by tributaries 
communicating with the vena salvatella, and 
with the deep veins of the palm by a branch 
Median CephaZfct 
Internal 
Cut a neout 
Nerve 
External- 
CutancoaslVe/'ve I 
-Medirt/n, 
Easily 
The Superficial Veins of the Upper Extremity. 624 
THE VEINS. 
which passes through the first interosseous space. It forms by the union of these 
tributaries a large vessel which ascends along the radial side of the forearm and 
receives numerous veins from both its surfaces. At the bend of the elbow it unites 
with the median cephalic to form the cephalic vein. 
The Median Vein collects the blood from the superficial structures on the pal- 
mar surface of the hand and middle line of the forearm, communicating with the 
anterior ulnar and radial veins. At the bend of the elbow it receives a branch of 
communication from the deep veins accompanying the brachial artery, and divides 
into two branches, the median cephalic and median basilic, which diverge from each 
other as they ascend. 
The Median Cephalic, usually the smaller of the twTo, passes outward in the 
groove between the Supinator longus and Biceps muscles, and joins with the radial 
to form the cephalic vein. The branches of the external cutaneous nerve pass 
beneath this vessel. 
The Median Basilic Vein passes obliquely inward, in the groove between the 
Biceps and Pronator radii teres, and joins the common ulnar to form the basilic. 
This vein passes in front of the brachial artery, from which it is separated by a 
fibrous expansion (the bicipital fascia} which is given off' from the tendon of the 
Biceps to the fascia covering the Flexor muscles of the forearm. Filaments of the 
internal cutaneous nerve pass in front as well as behind this vessel.1 
The Basilic is a vein of considerable size formed by the coalescence of the 
common ulnar vein with the median basilic. It passes upward along the inner side 
of the Biceps muscle, pierces the deep fascia a little below the middle of the arm, 
and ascends in the course of the brachial artery, terminating by joining the venae 
comites of that vessel to form the axillary vein. 
The Cephalic Vein courses along the outer border of the Biceps muscle to the 
upper third of the arm; it then passes in the interval between the Pectoralis major 
and Deltoid muscles, accompanied by the descending branch of the acromial tho- 
racic artery and the upper external cutaneous branch of the musculo-spiral nerve, 
pierces the costo-coracoid membrane, and terminates in the axillary vein just below 
the clavicle. This vein is occasionally connected with the external jugular or sub- 
clavian by a branch which passes from it upward in front of the clavicle. [In the 
living model the subcutaneous thoracic veins emptying into the cephalic in the inter- 
space between the Deltoid and the Pectoralis major make it look as if the cepha- 
lic terminated over the Pectoral muscle. Its main trunk, however, is lost on the 
surface when it becomes deeper, and hence the deceptive appearance.] 
The Deep Veins of the Upper Extremity follow the course of the arteries, 
forming their veme comites. They are generally two in number, one lying on each 
side of the corresponding artery, and they are connected at intervals by short 
transverse branches. 
There are two digital veins accompanying each artery along the sides of the 
fingers: these, uniting at their base, pass along the interosseous spaces in the palm, 
and terminate in the two venae comites, which accompany the superficial palmai' 
arch. Branches from these vessels on the radial side of the hand accompany the 
superficialis volae, and on the ulnar side terminate in the deep ulnar veins. The 
deep ulnar veins, as they pass in front of the wrist, communicate with the inter- 
osseous and superficial veins, and at the elbow unite with the deep radial veins to 
form the venae comites of the brachial artery. 
The Interosseous Veins accompany the anterior and posterior interosseous arte- 
ries. The anterior interosseous veins commence in front of the wrist, where they 
communicate with the deep radial and ulnar veins; at the upper part of the fore- 
arm they receive the posterior interosseous veins, and terminate in the venae com- 
ites of the ulnar artery. 
1 Cruveilhier says: "Numerous varieties are observed in the disposition of the veins of the elbow: 
sometimes the common median vein is wanting, but in those cases its two branches of bifurcation are 
furnished by the radial vein, and the cephalic is almost always in a rudimentary condition. In other 
cases only two veins are found at the bend of the elbow, the radial and ulnar, which are continuous, 
without any demarcation, with the cephalic and basilic." VEINS OF THE UPPER EXTREMITY. 
625 
The Deep Palmar Veins accompany the deep palmar arch, being formed .by 
tributaries which accompany the ramifications of that vessel. They communicate 
with the deep ulnar veins at the inner side of the hand, and on the outer side ter- 
minate in the venae comites of the radial artery. At the wrist they receive a dor- 
sal and a palmar tributary from the thumb, and unite with the deep radial veins. 
Accompanying the radial artery these vessels terminate in the venae comites of the 
brachial artery. 
The Brachial Veins are placed one on each side of the brachial artery, receiv- 
ing tributaries corresponding with the branches given off" from that vessel; at 
the lower margin of the axilla they unite with the basilic to form the axillary 
vein. 
The deep veins have numerous anastomoses, not only with each other, but also 
with the superficial veins. 
The Axillary Vein is of large size, and formed by the junction of the venae 
comites of the brachial artery with the basilic vein. It commences at the lower 
part of the axillary space, increases in size as it ascends by receiving tributaries 
corresponding with the branches of the axillary artery, and terminates immedi- 
ately beneath the clavicle at the outer margin of the first rib, where it becomes 
the subclavian vein. This vessel is covered in front by the Pectoral muscles 
and costo-coracoid membrane, and lies on the thoracic side of the axillary 
artery. Near its termination it receives the cephalic vein. This vein is pro- 
vided with a pair of valves opposite the lower border of the Subscapularis 
muscle; valves are also found at the termination of the cephalic and subscapular 
veins. 
The Subclavian Vein, the continuation of the axillary, extends from the outer 
margin of the first rib to the inner end of the sterno-clavicular articulation, where 
it unites with the internal jugular to form the innominate vein. It is in relation 
in front with the clavicle and Subclavius muscle; behind, with the subclavian artery, 
from which it is separated internally by the Scalenus anticus and phrenic nerve; 
below, it rests in a depression on the first rib and upon the pleura; above, it is 
covered by the cervical fascia and integument. 
The subclavian vein occasionally rises in the neck to a level with the third part 
of the subclavian artery, and in two instances has been seen passing with this ves- 
sel behind the Scalenus anticus. This vessel is usually provided with valves about 
an inch from its termination in the innominate, just external to the entrance of the 
external jugular vein. 
Tributaries.-It receives the external and anterior jugular veins and a small 
branch from the cephalic outside the Scalenus, and on the inner side of that muscle 
the internal jugular vein. 
The Innominate or Brachio-cephalic Veins (Fig. 417) are two large trunks 
placed one on each side of the root of the neck, and formed by the union of the inter- 
nal jugular and subclavian veins of the corresponding side. [It will be noticed that 
there are two innominate veins, but only one innominate artery. ] 
The Right Innominate Vein is a short vessel, an inch and a half in length, which 
commences at the inner end of the clavicle, and, passing almost vertically downward, 
joins with the left vena innominata just below the cartilage of the first rib, close to 
the right border of the sternum, to form the superior vena cava. It lies superficial 
and external to the arteria innominata; on its right side the pleura is interposed 
between it and the apex of the lung. This vein at the angle of junction of the 
internal jugular with the subclavian receives the right vertebral vein and right 
lymphatic duct, and lower down the right internal mammary, right inferior thyroid, 
and sometimes the right superior intercostal veins. 
The Left Innominate Vein, about three inches in length and larger than the 
right, passes from left to right across the upper and front part of the chest, at the 
same time inclining downward to unite with its fellow of the opposite side, forming 
the superior vena cava. It is in relation in front with the first piece of the sternum, 
from which it is separated by the Sterno-thyroid muscles, the thymus gland or its 626 
THE VEINS. 
remains, and some loose areolar tissue. Behind, it lies across the roots of the three 
large arteries arising from the 
arch of the aorta. This vessel 
is joined by the left vertebral, 
left inferior thyroid, left inter- 
nal mammary, and the left 
superior intercostal veins, and 
occasionally some thymic and 
pericardiac veins. [The tho- 
racic duct empties into the left 
innominate vein at the angle of 
junction of the internal jugu- 
lar and subclavian veins.] There 
are no valves in the venae inno- 
minatae. 
Peculiarities.-Sometimes the 
innominate veins open separately 
into the right auricle : in such cases 
the right vein takes the ordinary 
course of the superior vena cava, 
but the left vein, after communica- 
ting by a small branch with the 
right one, passes in front of the root 
of the left lung, and, turning to the 
back of the heart, receives the car- 
diac veins, and terminates in the 
back of the right auricle. This oc- 
casional condition of the veins in 
the adult is a regular one in the 
foetus at an early period, and the 
two vessels are persistent in birds 
and some Mammalia. The subse- 
quent changes which take place in 
these vessels are the following : The 
communicating branch between the 
two trunks enlarges and forms the 
future left innominate vein ; the re- 
maining part of the left trunk is 
obliterated as far as the heart, where 
it remains pervious and forms the 
coronary sinus: a remnant of the 
obliterated vessel is seen in adult 
life as a fibrous band passing along 
the back of the left auricle and in 
front of the root of the left lung, 
called by Mr. Marshall the vestigial 
fold of the pericardium. 
The Internal Mammary 
Veins, two in number to each 
artery, follow the course of that 
vessel, and receive branches 
corresponding with those de- 
rived from it. The two veins 
on each side unite into a single 
trunk, which terminates in the 
innominate vein. 
The Inferior Thyroid 
Veins, two (frequently three 
or four) in number, arise in 
the venous plexus on the thy- 
roid body, communicating with 
the middle and superior' thyroid veins. The left one descends in front of the trachea, 
Fig. 417. 
-Anttrio r J'ugultw 
Superior Thyroidr 
'Midd.le ThuroiA 
-JSxtfirtial Jugular 
AJediarttnal f 
Phrenic > 
-Supra-Renal 
Siipm-jRinal- 
The Venae Cavae and Azygos Veins, with their formative branches. VEINS OF THE UPPER EXTREMITY. 
627 
behind the Sterno-thyroid muscle, communicating with its fellow by tranverse branches, 
and terminates in the left vena innominata. The right one, which is placed a little to 
the right of the median line, opens into the right vena innominata just at its junc- 
tion with the superior cava. These veins receive oesophageal, tracheal, and inferior 
laryngeal branches, and are provided with valves at their termination in the innomi- 
nate veins. 
The Superior Intercostal Veins return the blood from the upper intercostal spaces. 
The right superior intercostal, much smaller than the left, closely corresponds 
with the superior intercostal artery, receiving the blood from the first or first and 
second intercostal spaces, and, passing downward, terminates in the vena azygos 
major. Occasionally it opens into the right innominate vein. 
The left superior intercostal is always larger than the right, but varies in size 
in different subjects, being small when the left upper azygos vein is large, and vice 
versd. It is usually formed by branches from the two or three upper intercostal 
spaces, and, passing across the arch of the aorta, terminates in the left vena innomi- 
nata. The left bronchial vein and the left superior phrenic open into it. 
The Superior Vena Cava receives the blood which is conveyed to the heart 
from the whole of the upper half of the body [and also the contents of the right 
lymphatic and the thoracic ducts]. It is a short trunk, varying from two inches and 
a half to three inches in length, formed by the junction of the two vense innominatee. 
It commences immediately below the cartilage of the first rib close to the sternum 
on the right side, and, descending vertically, enters the pericardium about an 
inch and a half above the heart, and terminates in the upper part of the right auri- 
cle opposite the upper border of the third costal cartilage. At the angle of junc- 
tion of the two innominate veins the right superior phrenic opens into the superior 
vena cava. In its course it describes a slight curve, the convexity of which is 
turned to the right side. 
Relations.-In front with the pericardium and process of cervical fascia, which 
is continuous with it; this separates it from the thymus gland and from the sternum ; 
behind with the root of the right lung; on its right side with the phrenic nerve 
and right pleura; on its left side with the commencement of the innominate artery 
and the ascending part of the aorta. The portion contained within the pericardium 
is covered by the serous layer of that membrane in its anterior three-fourths. It 
receives the vena azygos major just before it enters the pericardium, and several 
small veins from the pericardium and parts in the mediastinum. The superior 
vena cava has no valves. 
The Azygos Veins connect together the superior and inferior venm cavae, sup- 
plying the place of those vessels in the part of the chest which is occupied by the 
heart. 
The larger, or right azygos vein \_azygos major], commences opposite the first or 
second lumbar vertebra by a branch from the right lumbar veins (the ascending 
lumbar), sometimes by a branch from the right renal vein or from the inferioi' vena 
cava. It enters the thorax through the aortic opening into the Diaphragm, and 
passes along the right side of the vertebral column to the fourth dorsal vertebra, 
where it arches forward over the root of the right lung, and terminates in the 
superior vena cava just before that vessel enters the pericardium. Whilst passing 
through the aortic opening of the Diaphragm it lies with the thoracic duct on the 
right side of the aorta; and in the thorax it lies upon the intercostal arteries, on 
the right side of the aorta and thoracic duct, in the posterior mediastinum. 
Tributaries.-It receives nine or ten lower intercostal veins of the right side, 
the vena azygos minor, several oesophageal, mediastinal, and pericardial veins; near 
its termination the right bronchial vein ; and is occasionally connected with the right 
superior intercostal vein. A few imperfect valves are found in this vein, but its 
tributaries are provided with complete valves. 
The intercostal veins on the left side, below the two or three upper intercostal 
spaces, usually form two trunks, named the left lower and the left upper azygos 
veins. 628 
THE VEINS. 
The left lower, or smaller azygos vein [azygos minor], commences in the lumbar 
region by a branch from one of the lumbar veins (ascending lumbar) or from the 
left renal. It passes into the thorax through the left crus of the Diaphragm, and, 
ascending on the left side of the spine as high as the seventh or eighth dorsal verte- 
bra, passes across the column, behind the aorta and thoracic duct, to terminate in 
the right azygos vein. It receives the four or five lower intercostal veins of the left 
side, and some oesophageal and mediastinal veins. 
The left upper azygos vein varies according to the size of the left superior inter- 
costal. It receives veins from the intercostal spaces between the left superior inter- 
costal vein and highest tributary of the left lower azygos. They are usually two or 
three in number, and join to form a trunk which ends in the right azygos vein or 
in the left lower azygos. It sometimes receives the left bronchial vein. When this 
vein is small or altogether wanting, the left superior intercostal vein will extend as 
low as the fifth or sixth intercostal space.1 
The bronchial veins return the blood from the substance of the lungs: that of 
the right side opens into the vena azygos major near its termination; that of the 
left side, into the left superior intercostal vein or left upper azygos vein. 
The numerous venous plexuses placed upon and within the spine may be arranged 
into four sets: 
1. Those placed on the exterior of the spinal column (the dorsi-spinal veins). 
2. Those situated in the interior of the spinal canal, between the vertebras and 
the theca vertebralis (gneningo-rachidian veins). 
3. The veins of the bodies of the vertebrae (pence basis vertebrarum). 
4. The veins of the spinal cord (medulli-spinaV). 
1. The Dorsi-spinal Veins commence by small branches which receive their 
blood from the integument of the back of the spine and from the muscles in the 
vertebral grooves. They form a 
complicated network, which sur- 
rounds the spinous processes, the 
laminae, and the transverse and ar- 
ticular processes of all the vertebrae. 
At the bases of the transverse pro- 
cesses they communicate, by means 
of ascending and descending branches, 
with the veins surrounding the con- 
tiguous vertebrae, and they join with 
the veins in the spinal canal by 
branches which perforate the liga- 
menta subflava. Other branches 
pass obliquely forward between the 
transverse processes, and communi- 
cate with the intraspinal veins through 
the intervertebral foramina. They 
terminate by joining the vertebral 
veins in the neck, the intercostal 
veins in the thorax, and the lumbar 
and sacral veins in the loins and 
pelvis. 
2. The Meningo-rachidian Veins.-The principal veins contained in the spinal 
The Spinal Veins. 
Fig. 418. 
Transverse Section of a Dorsal Vertebra, showing the 
Spinal Veins. 
1 For an account of the arrangement of the azygos and superior intercostal veins in a number of 
consecutive cases from the same dissecting-room, see a paper by Mr. B. G. Morison, Journ. of Anat. and 
Phys., vol. xiii. p. 346. The most important difference between his description and that in the text is 
that he always found two superior intercostal veins on both sides, the vein from the first space being 
separate and joining the corresponding innominate vein. The lower (and larger) superior intercostal 
vein he describes as opening into the azygos on the right and innominate on the left side. THE SPINAL VEINS. 
629 
canal are situated between the theca vertebralis and the vertebrae. They consist of 
two longitudinal plexuses, one of which 
runs along the posterior surface of the 
bodies of the vertebrae throughout the 
entire length of the spinal canal (anterior 
longitudinal spinal veins'), receiving the 
veins belonging to the bodies of the ver- 
tebrae (vence basis vertebrarum). The 
other plexus (posterior longitudinal spi- 
nal veins) is placed on the inner or ante- 
rior surface of the laminae of the verte- 
brae, and extends also along the entire 
length of the spinal canal. 
The Anterior Longitudinal Spinal 
Veins consist of two large, tortuous, 
venous canals which extend along the 
whole length of the vertebral column 
from the foramen magnum, where they 
communicate by a venous ring around that opening, to the base of the coccyx, being 
placed one on each side of the posterior surface of the bodies of the vertebrae, along 
the margin of the posterior common ligament. These veins communicate together 
opposite each vertebra by transverse trunks which pass beneath the ligament and 
receive the large venae basis vertebrarum from the interior of the body of each ver- 
tebra. The anterior longitudinal spinal veins are least developed in the cervical and 
sacral regions. They are not of uniform size throughout, being alternately enlarged 
and constricted. At the intervertebral foramina they communicate with the dorsi- 
spinal veins and with the vertebral veins in the neck, with the intercostal veins in the 
dorsal region, and with the lumbar and sacral veins in the corresponding regions. 
The Posterior Longitudinal Spinal Veins, smaller than the anterior, are situated 
one on either side, between the inner surface of the laminse and the theca vertebralis. 
They communicate (like the anterior) opposite each vertebra by transverse trunks, 
and with the anterior longitudinal veins by lateral transverse branches which pass 
from behind forward. These veins, by branches which perforate the ligamenta 
subflava, join with the dorsi-spinal veins. From them branches are given off 
which pass through the intervertebral foramina and join the vertebral, intercostal, 
lumbar, and sacral veins. 
3. The Veins of the Bodies of the Vertebrae (venae basis vertebrarum) emerge 
from the foramina on their posterior surface, and join the transverse trunk connect- 
ing the anterior longitudinal spinal veins. They are contained in large tortuous 
channels in the substance of the bones, similar in every respect to those found in 
the diploe of the cranial bones. These canals lie parallel to the upper and lower 
surface of the bones. They commence by small openings on the front and sides of 
the bodies of the vertebrae, through which communicating branches from the veins 
external to the bone pass into its substance, and converge to the principal canal, 
which is sometimes double toward its posterior part, and open into the correspond- 
ing transverse branch uniting the anterior longitudinal veins. They become greatly 
developed in advanced age. 
4. The Veins of the Spinal Cord (medulli-spinal) consist of a minute tortuous, 
venous plexus which covers the entire surface of the cord, being situated between the 
pia mater and arachnoid. These vessels emerge chiefly from the median furrows, and 
are largest in the lumbar region. Near the base of the skull they unite and form two 
or three small trunks which communicate with the vertebral veins, and then terminate 
in the inferior cerebellar veins or in the inferior petrosal sinuses. Each of the spinal 
nerves is accompanied by a branch as far as the intervertebral foramina, where they 
join the other veins from the spinal canal. 
There are no valves in the spinal veins. 
Fig. 419. 
Vertical Section of Two Dorsal Vertebrae, showing the 
Spinal Veins. 630 
THE VEINS. 
VEINS OF THE LOWER EXTREMITY. 
The veins of the lower extremity are subdivided, like those of the upper, into two 
sets, superficial and deep, the superficial veins being 
placed beneath the integument between the two layers 
of superficial fascia, the deep veins accompanying the 
arteries and forming the venae comites of those vessels. 
Both sets of veins are provided with valves, which are 
more numerous in the deep than in the superficial set. 
These valves are also more numerous in the lower than 
in the upper limb. 
The Superficial Veins of the lower extremity are 
the internal or long saphenous and the external or short 
saphenous. 
On the dorsum of the foot is a venous arch situated 
in the superficial structures over the anterior extremities 
of the metatarsal bones. It has its convexity directed 
forward, and receives digital tributaries from the upper 
surface of the toes; at its concavity 
it is joined by numerous small veins 
which form a plexus on the dorsum 
of the foot. The arch terminates in- 
ternally in the long saphenous, exter- 
nally in the short saphenous vein. 
The Internal or Long- Saphe- 
nous Vein manifest, easily 
seen] (Fig. 420) commences at the 
inner side of the arch on the dorsum 
of the foot; it ascends in front of the 
inner malleolus and along the inner 
side of the leg, behind the inner mar- 
gin of the tibia, accompanied by the 
internal saphenous nerve. At the 
knee it passes backward behind the 
inner condyle of the femur, then as- 
cends along the inside of the thigh, 
and, passing through the saphenous 
opening in the fascia lata, terminates 
in the femoral vein about an inch and 
a half below Poupart's ligament. 
This vein receives in its course cuta- 
neous tributaries from the leg and 
thigh, and at the saphenous opening 
the superficial epigastric, superficial 
circumflex iliac, and external pudic 
veins. The veins from the inner 
and back part of the thigh fre- 
quently unite to form a large vessel 
which enters the main trunk near 
the saphenous opening; and some- 
times those on the outer side of the 
thigh join to form another large 
vessel; so that occasionally three 
large veins are seen converging 
from different parts of the thigh 
toward the saphenous opening. The 
internal saphenous vein communicates in the foot with the internal plantar vein; 
Fig. 420. 
Fig. 421. 
The Internal or Long Saphenous 
Vein and its Branches. 
External or Short Saph- 
enous Vein [right leg]. VEINS OF THE LOWER EXTREMITY. 
631 
in the leg, with the posterior tibial veins by branches which perforate the tibial 
origin of the Soleus muscle and also with the anterior tibial veins; at the knee, 
with the articular veins ; in the thigh, with the femoral vein by one or more branches. 
The valves in this vein vary from two to six in number; they are more numerous in 
the thigh than in the leg. 
The External or Short Saphenous Vein (Fig. 421) commences at the outer 
side of the arch on the dorsum of the foot; it ascends behind the outer malleolus 
and along the outer border of the tendo Achillis, across which it passes at an acute 
angle to reach the middle line of the posterior aspect of the leg. Passing directly 
upward, it perforates the deep fascia in the lower part of the popliteal space, and 
terminates in the popliteal vein, between the heads of the Gastrocnemius muscle.1 
It is accompanied by the external saphenous nerve. It receives numerous large 
tributaries from the back part of the leg, and communicates with the deep veins on 
the dorsum of the foot and behind the outer malleolus. Before it perforates the deep 
fascia it gives off' a communicating branch which passes upward and inward to join 
the internal saphenous vein. This vein has a variable number of valves, from three 
to nine (Gay), one of which is always found near its termination in the popliteal 
vein. 
The Deep Veins of the lower extremity accompany the arteries and their 
branches, and are called the venoe comites of those vessels. 
The External and Internal Plantar veins unite to form the posterior tibial. 
They accompany the posterior tibial artery and are joined by the peroneal veins. 
The Anterior Tibial Veins are formed by a continuation upward of the venae 
comites of the dorsalis pedis artery. They pass between the tibia and fibula, above 
the upper border of the interosseous membrane, and form, by their junction with 
the posterior tibial, the popliteal vein. 
The valves in the deep veins are very numerous. 
The Popliteal Vein is formed by the junction of the venae comites of the 
anterior and posterior tibial vessels; it ascends through the popliteal space to the 
tendinous aperture in the Adductor magnus, where it becomes the femoral vein. In 
the lower part of its course it is placed internal to the artery ; between the heads 
of the Gastrocnemius it is superficial to that vessel, but above the knee-joint it is 
close to its outer side. It receives the sural veins from the Gastrocnemius muscle, 
the articular veins, and the external saphenous. The valves in this vein are usually 
four in number. 
The Femoral Vein accompanies the femoral artery through the upper two-thirds 
of the thigh. In the lower part of its course it lies external to the artery ; higher 
up it is behind it, and beneath Poupart's ligament it lies to its inner side and on the 
same plane. It receives numerous muscular tributaries: the profunda femoris 
joins it near its termination, and about an inch and a half below Poupart's lig- 
ament the internal saphenous vein. The valves in this vein are four or five in 
number. 
The External Iliac Vein commences at the termination of the femoral 
beneath the crural arch, and, passing upward along the brim of the pelvis, ter- 
minates opposite the sacro-iliac symphysis by uniting with the internal iliac to form 
the common iliac vein. On the right side it lies at first along the inner side of the 
external iliac artery, but as it passes upward gradually inclines behind it. On the 
left side it lies altogether on the inner side of the artery. It receives immediately 
above Poupart's ligament the epigastric and circumflex iliac veins and a small pubic 
vein corresponding to the pubic branch of the obturator artery. According to 
Friedreich, it frequently contains one and sometimes two valves. 
The Internal Iliac Vein is formed by the venae comites of the branches of the 
1 Mr. Gay calls attention to the fact that the external saphenous vein often (he says invariably) 
penetrates the fascia at or about the point where the tendon of the Gastrocnemius commences, and 
runs below the fascia in the rest of its course, or sometimes among the muscular fibres, to join the 
popliteal vein. (See Gay on Varicose Disease of the Lower Extremities, p. 24, where there is also a. 
careful and elaborate description of the branches of the saphenous veins.) 632 
THE VEINS. 
internal iliac artery, the umbilical arteries excepted. It receives the blood from 
the exterior of the pelvis by the gluteal, sciatic, internal pudic, and obturator 
veins, and from the organs in the cavity of the pelvis by the hemorrhoidal and 
vesico-prostatic plexuses in the male and the uterine and vaginal plexuses in the 
female. The vessels forming these plexuses are remarkable for their large size, 
their frequent anastomoses, and the number of valves which they contain. The 
internal iliac vein lies at first on the inner side, and then behind the internal iliac 
artery, and terminates opposite the sacro-iliac articulation by uniting with the 
external iliac to form the common iliac vein. This vessel has no valves. 
The Hemorrhoidal Plexus surrounds the lower end of the rectum, being 
formed by the superior hemorrhoidal veins (tributaries of the inferior mesenteric) 
and the middle and inferior hemorrhoidal, which terminate in the internal iliac. 
The portal and general venous systems have a free communication by means of the 
branches composing this plexus. 
The Vesico-prostatic Plexus surrounds the neck and base of the bladder and 
prostate gland. It communicates with the hemorrhoidal plexus behind, and receives 
the dorsal vein of the penis, which enters the pelvis beneath the subpubic ligament. 
This plexus is supported upon the sides of the bladder by a reflection of the pelvic 
fascia. The veins composing it are very liable to become varicose, and often contain 
hard earthy concretions called phleboliths [?. e. " vein-stones." These are not uncom- 
mon in varicose veins of the leg also, especially in the pouches behind the valves]. 
The Dorsal Vein of the Penis is a vessel of large size which returns the blood 
from the body of that organ. At first it consists of two branches, which are con- 
tained in the groove on the dorsum of the penis, and it receives veins from the 
glans, the corpus spongiosum, and numerous superficial veins; these unite near the 
root of the penis into a single trunk, which passes through the suspensory ligament 
of the penis, pierces the triangular ligament beneath the pubic arch, and divides 
into two branches which enter the prostatic plexus. 
The Vaginal Plexus surrounds the mucous membrane, being especially devel- 
oped at the orifice of the vagina; it communicates with the vesical plexus in front 
and with the hemorrhoidal plexus behind. 
The Uterine Plexus is situated along the sides and superior angles of the uterus 
between the layers of the broad ligament, receiving large venous canals (the uterine 
sinuses) from the substance of the uterus. The veins composing this plexus anas- 
tomose frequently with each other and with the ovarian veins. They are not tor- 
tuous like the arteries. 
The Common Iliac Veins are formed by the union of the external and internal 
iliac veins in front of the sacro-iliac articulation; passing obliquely upward toward 
the right side, they terminate upon the intervertebral substance between the fourth 
and fifth lumbar vertebrae, where the veins of the two sides unite at an acute angle 
to form the inferior vena cava. The right common iliac is shorter than the left, 
nearly vertical in its direction, and ascends behind, and then to the outer side of 
its corresponding artery. The left common iliac, longer and more oblique in its 
course, is at first situated on the inner side of the corresponding artery, and then 
behind the right common iliac. Each common iliac receives the ilio-lumbar and 
sometimes the lateral sacral veins. The left receives in addition the middle sacral 
vein. No valves are found in these veins. 
The Middle Sacral Veins accompany the corresponding artery along the front 
of the sacrum, and terminate in the left common iliac vein; occasionally in the 
angle of junction of the two iliac veins. 
Peculiarities.-The left common iliac vein, instead of joining with the right in its usual 
position, occasionally ascends on the left side of the aorta as high as the kidney, where, after 
receiving the left renal vein, it crosses over the aorta, and then joins with the right vein to form 
the vena cava. In these cases the two common iliacs are connected by a small communicating 
branch at the spot where they are usually united.1 
1 See two cases which have been described by Mr. Walsham in the St. Bartholomew's Hospital 
.Reports, vols. xvi. and xvii. REZAS OF THE LOWER EXTREMITY. 
633 
The Inferior Vena Cava returns to the heart the blood from all the parts below 
the Diaphragm. It is formed by the junction of the two common iliac veins on the 
right side of the intervertebral substance between the fourth and fifth lumbar verte- 
brae. It passes upward along the front of the spine on the right side of the aorta, and, 
having reached the under surface of the liver, is contained in a groove in its pos- 
terior border. It then perforates the central tendon of the Diaphragm, enters the 
pericardium, where it is covered by its serous layer, and terminates in the lower 
and back part of the right auricle. At its termination in the auricle it is provided 
with a valve, the Eustachian, which is of large size during foetal life. 
Relations.-In front, from below upward, with the mesentery, right spermatic 
artery, transverse portion of the duodenum, the pancreas, portal vein, and the pos- 
terior border of the liver, which partly and occasionally completely surrounds it; 
behind, with the vertebral column, the right crus of the Diaphragm, the right renal 
and lumbar arteries, right semilunar ganglion; on the left side, with the aorta. It 
receives in its course the following branches: 
Lumbar. 
Right Spermatic. 
Renal. 
Suprarenal. 
Phrenic. 
Hepatic. 
Peculiarities in Position.-This vessel is sometimes placed on the left side of the aorta 
as high as the left renal vein, after receiving which it crosses over to its usual position on the 
right side ; or it may be placed altogether on the left side of the aorta, as far upward as its 
termination in the heart: in such cases the abdominal and thoracic viscera, together with the 
great vessels, are all transposed. 
Point of Termination.-Occasionally the inferior vena cava joins the right azygos vein, 
which is then of large size. In such cases the superior cava receives the whole of the blood from 
the body before transmitting it to the right auricle, except the blood from the hepatic veins, 
which passes directly into the right auricle. 
The Lumbar Veins, three or four in number on each side, collect the blood by 
dorsal tributaries from the muscles and integument of the loins, and by abdominal 
tributaries from the walls of the abdomen, where they communicate with the epigas- 
tric veins. At the spine they receive veins from the spinal plexuses, and then pass 
forward, round the sides of the bodies of the vertebrae beneath the Psoas magnus, 
and terminate at the back part of the inferior cava. The left lumbar veins are 
longer than the right, and the aorta. The lumbar veins communicate 
with each other by branches which pass in front of the transverse processes. These 
veins are connected together by a longitudinal vessel which passes in front of the 
transverse processes of the lumbar vertebrae, and, communicating with each lumbar 
vein, is called the ascending lumbar. It forms the most frequent origin of the cor- 
responding vena azygos, and serves to connect the common iliac, ilio-lumbar, lum- 
bar, and azygos veins of the corresponding side of the body. 
The Spermatic Veins emerge from the back of the testis and receive tributaries 
from the epididymis; they form a branched and convoluted plexus called the sper- 
matic plexus (plexus pampiniformis} below the abdominal ring: the vessels com- 
posing this plexus are very numerous, and ascend along the cord in front of the vas 
deferens; having entered the abdomen through the inguinal canal, they coalesce to 
form two branches, which ascend on the Psoas muscle behind the peritoneum, lying 
one on each side of the spermatic artery, and unite to form a single vessel which 
opens on the right side into the inferior vena cava at an acute angle-on the left 
side into the left renal vein at a right angle. The spermatic veins are provided 
with valves.1 The left spermatic vein passes behind the sigmoid flexure of the 
colon, a part of the intestine in which fecal accumulation is common: this circum- 
stance, as well as the indirect communication of the vessel with the inferior vena 
cava, may serve to explain the more frequent occurrence of varicocele on the left 
side. 
1 Rivington has pointed out that a valve is usually found at the orifices of both the right and left 
spermatic veins. When no valves exist at the opening of the left spermatic vein into the left renal 
vein, valves are generally present in the renal vein within a quarter of an inch from the orifice of 
the spermatic vein {Journal of Anatomy and Physiology, vol. vii. p. 163). 634 
THE VEINS. 
The Ovarian Veins are analogous to the spermatic in the male; they form a 
plexus near the ovary and in the broad ligament and Fallopian tube, communicating 
with the uterine plexus. They terminate as in the male. Valves are occasionally 
found in these veins. These vessels, like the uterine veins, become much enlarged 
during pregnancy. 
The Renal Veins are of large size and placed in front of the renal arteries.1 
The left is longer than the right, and passes in front of the aorta just below the 
origin of the superior mesenteric artery. It receives the left spermatic, the left 
inferior phrenic, and generally the left suprarenal veins. It opens into the vena 
cava a little higher than the right. 
The Suprarenal Veins terminate on the right side in the cava; on the left 
side, in the left renal or phrenic vein. 
The Phrenic Veins follow the course of the phrenic arteries. The two superior, 
of small size, accompany the phrenic nerve and comes nervi phrenici artery, the 
right terminating opposite the junction of the two venae innominatae, the left in the 
left superior intercostal or left internal mammary. The two inferior phrenic veins 
follow the course of the phrenic arteries, and terminate, the right in the inferior 
vena cava, the left in the left renal vein. 
The Hepatic Veins commence in the substance of the liver, in the capillary 
terminations of the portal vein and hepatic artery: these tributaries, gradually 
uniting, usually form three large veins, which converge toward the posterior border 
of the liver and open into the inferior vena cava, whilst that vessel is situated in the 
groove at the back part of this organ. Of these three veins, one from the right and 
another from the left lobe open obliquely into the vena cava, that from the middle of 
the organ and lobulus Spigelii having a straight course. The hepatic veins run singly 
and are in direct contact with the hepatic tissue. They are destitute of valves. 
The portal venous system is composed of four large veins which collect the 
venous blood from the viscera of digestion. The trunk formed by their union 
(vena porta?) enters the liver and ramifies throughout its substance, and its branches, 
again emerging from that organ as the hepatic veins, terminate in the inferior vena 
cava. The branches of this vein are in all cases single and destitute of valves. 
The veins forming the portal system are the 
Portal System of Veins. 
Inferior Mesenteric. 
Superior Mesenteric. 
Splenic. 
Gastric. 
The Inferior Mesenteric Vein returns the blood from the rectum, sigmoid 
flexure, and descending colon, corresponding with the ramifications of the branches 
of the inferior mesenteric artery. Ascending beneath the peritoneum in the lumbar 
region, it passes behind the transverse portion of the duodenum and pancreas and 
terminates in the splenic vein. Its hemorrhoidal branches inosculate with those of 
the internal iliac, and thus establish a communication between the portal and the 
general venous system.2 
The Superior Mesenteric Vein returns the blood from the small intestines and 
from the caecum and ascending and transverse portions of the colon, corresponding 
with the distribution of the branches of the superior mesenteric artery. The large 
trunk formed by the union of these branches ascends along the right side and in 
1 The student may observe that all veins above the Diaphragm which do not lie on the same plane 
as the arteries which they accompany lie in front of them; and that all veins below the Diaphragm 
which do not lie on the same plane as the arteries which they accompany lie behind them, except 
the renal and profunda femoris vein. 
2 Besides this anastomosis between the portal vein and the branches of the vena cava, other anas- 
tomoses between the portal and systemic veins are formed by the communication between the gastric 
veins and the oesophageal veins, which empty themselves into the vena azygos minor, between the left 
renal vein and the veins of the intestines, especially of the colon and duodenum, and between super- 
ficial branches of the portal veins of the liver and the phrenic veins, as pointed out by Mr. Kiernan. 
(See Physiological Anatomy, by Todd and Bowman, 1859, vol. ii. p. 348.) FOETAL SYSTEM OF VEINS. 
635 
front of the corresponding artery, passes in front of the transverse portion of the 
duodenum, and unites behind the upper border of the pancreas with the splenic 
vein to form the vena portge. It receives the right gastro-epiploic vein. 
The Splenic Vein commences by five or six large branches, which return the 
blood from the substance of the spleen. These uniting form a single vessel, which 
passes from left to right behind the upper border of the pancreas below the artery, 
Fig. 422. 
Portal Vein and its Branches.1 
and terminates at its greater end by uniting at a right angle with the superior 
mesenteric to form the vena portae. The splenic vein is of large size, and not tor- 
tuous like the artery. It receives the vasa brevia from the left extremity of the 
stomach, the left gastro-epiploic vein, pancreatic branches from the pancreas, the 
pancreatico-duodenal vein, and the inferior mesenteric vein. 
The Gastric Veins are two in number: one, a small vein, corresponds to the 
pyloric branch of the hepatic artery; the other, considerably larger, corresponds to 
1 In this diagram the right gastro-epiploic vein opens into the splenic vein ; generally it empties 
into the superior mesenteric, close to its termination. 636 
THE VEINS. 
the gastric artery. The former (pyloric, Walsham) runs along the lesser curvature 
of the stomach toward the pyloric end, receives branches from the pylorus and duo- 
denum, and ends in the vena portae. The latter (coronary, Walsham) begins near 
the pylorus, runs along the lesser curvature of the stomach toward the oesophageal 
opening, and then curves downward and backward between the folds of the lesser 
omentum to end in the vena portae.1 
The Portal Vein is formed by the junction of the-superior mesenteric and 
splenic veins, their union taking place in front of the vena cava and behind the 
upper border of the great end of the pancreas. Passing upward through the right 
border of the lesser omentum to the under surface of the liver, it enters the trans- 
verse fissure, where it is somewhat enlarged, forming the sinus of the portal vein, 
and divides into two branches, which accompany the ramifications of the hepatic 
artery and hepatic duct throughout the substance of the liver. Of these two 
branches, the right is the larger but the shorter of the two. The portal vein is 
about three or four inches in length, and, whilst contained in the lesser omentum, 
lies behind and between the hepatic duct and artery, the former being to the right, 
the latter to the left. These structures are accompanied by filaments of the hepatic 
plexus of nerves and numerous lymphatics, surrounded by a quantity of loose areo- 
lar tissue (capsule of Grlissori), and placed between the layers of the lesser omentum. 
The vena yortae receives the gastric and cystic veins; the latter vein sometimes ter- 
minates in the right branch of the vena portae. Within the liver the portal vein 
receives the blood from the branches of the hepatic artery. 
The veins which return the blood from the substance of the heart are the 
Cardiac Veins. 
Great Cardiac Vein. 
Middle Cardiac Vein. 
Posterior Cardiac Veins. 
Anterior Cardiac Veins. 
Right or Small Cardiac Vein. 
Venae Thebesii. 
The Great Cardiac Vein (coronary) is a vessel of considerable size which com- 
mences at the apex of the heart and ascends along the anterior interventricular 
groove to the base of the ventricles. It then curves to the left side, around the 
auriculo-ventricular groove, between the left auricle and ventricle, to the back part 
of the heart, and opens into the coronary sinus, its aperture being guarded by two 
valves. It receives in its course tributaries from both ventricles, but especially the 
left, and also from the left auricle; one of these, ascending along the thick margin 
of the left ventricle, is of considerable size. The vessels joining it are provided 
with valves. 
The Middle Cardiac Vein commences by small tributaries at the apex of the 
heart, communicating with those of the preceding. It ascends along the posterior 
interventricular groove to the base of the heart, and terminates in the coronary 
sinus, its orifice being guarded by a valve. It receives the veins from the posterior 
surface of both ventricles. 
The Posterior Cardiac Veins are three or four small vessels which collect the 
blood from the posterior surface of the left ventricle and open into the lower border 
of the coronary sinus. 
The Anterior Cardiac Veins are three or four small vessels which collect the 
blood from the anterior surface of the right ventricle. One of these (the vein of 
Gralen), larger than the rest, runs along the right border of the heart. They open 
separately into the lower part of the right auricle. 
The Right or Small Coronary Vein runs along the groove between the right 
auricle and ventricle, to open into the right extremity of the coronary sinus. It 
receives blood from the back part of the right auricle and ventricle. 
1 The above description of the gastric vein is the one given by Mr. Walsham, and differs from that 
usually found in the text-books. Since the publication of Mr. Walsham's paper I have verified the 
truth of his description. (See Journal of Anatomy and Physiology, vol. xiv. p. 399.) CARDIAC VEINS. 
637 
The Venae Thebesii are numerous minute veins which return the blood directly 
from the muscular substance, without entering the venous current. They open by 
minute orifices [foramina Thebesii} on the inner surface of the right auricle. 
The Coronary Sinus is that portion of the great cardiac vein which is situated 
in the posterior part of the left auriculo-ventricular groove. It is about an inch in 
length, presents a considerable dilatation, and is covered by the muscular fibres of 
the left auricle. It receives the veins enumerated above, and an oblique vein from 
the back part of the left auricle, the remnant of the obliterated left innominate 
trunk of the foetus, described by Mr. Marshall. The coronary sinus terminates in 
the right auricle, between the inferior vena cava and the auriculo-ventricular aper- 
ture, its orifice being guarded by a semilunar fold of the lining membrane of the 
heart, the coronary valve. All the branches joining this vessel, excepting the 
oblique vein above mentioned, are provided with valves. Of the Lymphatics. 
THE Lymphatics have derived their name from the appearance of the fluid con- 
tained in their interior (lympha, water). They are also called absorbents, from 
the property they possess of absorbing certain materials from the tissues and convey- 
ing them into the circulation. 
The lymphatic system includes not only the lymphatic vessels and the glands 
through which they pass, but also the lacteal or chyliferous vessels. The lacteals 
are the lymphatic vessels of the small intestine, and differ in no respect from the 
lymphatics generally, excepting that they contain a milk-white fluid, the chyle, dur- 
ing the process of digestion, and convey it into the blood through the thoracic duct. 
The lymphatics are exceedingly delicate vessels, the coats of which are so trans- 
parent that the fluid they contain is readily seen through them. They retain a 
nearly uniform size, being interrupted at intervals by constrictions which give them 
a knotted or beaded appearance. These constrictions are due to the presence of 
valves in their interior. Lymphatics have been found in nearly every texture and 
organ of the body which contains blood-vessels. Such non-vascular structures as 
cartilage, the nails, cuticle, and hair have none, but with these exceptions it is prob- 
able that eventually all parts will be found to be permeated by these vessels. 
The lymphatics are arranged into a superficial and deep set. The superficial 
lymphatics, on the surface of the body, are placed immediately beneath the integu- 
ment accompanying the superficial veins; they join the deep lymphatics in certain 
situations by perforating the deep fascia. In the interior of the body they lie in the 
submucous areolar tissue throughout the whole length of the gastro-pulmonary and 
genito-urinary tracts, and in the subserous areolar tissue in the cranial, thoracic, and 
abdominal cavities. The method of their origin has been described along with the 
other details of their minute anatomy (p. 85). Here it will be sufficient to say that 
a plexiform network of minute lymphatics may be found interspersed among the 
proper elements and blood-vessels of the several tissues, the vessels composing which, 
as well as the meshes between them, are much larger than those of the capillary 
plexus. From these networks small vessels emerge, which pass either to a neigh- 
boring gland or to join some larger lymphatic trunk. The deep lymphatics, fewer 
in number and larger than the superficial, accompany the deep blood-vessels. Their 
mode of origin is probably similar to that of the superficial vessels. The lymphatics 
of any part or organ exceed the veins in number, but in size they are much smaller. 
Their anastomoses also, especially those of the large trunks, are more frequent, and 
are effected by vessels equal in diameter to those which they connect, the continuous 
trunks retaining the same diameter. 
The lymphatic or absorbent glands, named also conglobate glands, are small 
solid glandular bodies situated in the course of the lymphatic and lacteal vessels. 
They are found in the neck and on the external parts of the head; in the upper 
extremity, in the axilla and in front of the elbow; in the lower extremity, in the 
groin and popliteal space, and in some other situations. In the abdomen they are 
found in large numbers in the mesentery and along the side of the aorta, vena cava, 
and iliac vessels; and in the thorax, in the anterior and posterior mediastina. They 
are somewhat flattened and of a round or oval form. In size they vary from a hemp- 
seed to an almond, and their color, on section, is of a pinkish-gray tint, excepting 
the bronchial glands, which in the adult are mottled with black. [It is important 
that the student, by examination of these glands in his own groin, should familiarize 
himself with their normal size. In the axilla they are not usually perceptible at all, 
unless enlarged by disease.] Each gland has a layer or capsule of cellular tissue 
investing it, from which prolongations dip into its substance, forming partitions. 
The lymphatic and lacteal vessels pass through these bodies in their passage to the 
638 THORACIC DUCT. 
639 
thoracic and lymphatic ducts. A lymphatic or lacteal vessel previous to entering 
a gland divides into several small branches, which are named afferent vessels. As 
they enter, their external coat becomes continuous with the capsule of the gland, and 
the vessels, much thinned and consisting only of their internal or endothelial coat, 
pass into the gland and branch out upon and in the tissue of the capsule, these 
branches opening into the lymph-sinuses of the gland. From these sinuses fine 
branches proceed to form a plexus, the vessels of which unite to form a single effer- 
ent vessel, which on emerging from the gland is again invested with an external coat. 
(Further details on the minute anatomy of the lymphatic vessels and glands will be 
found in the chapter on General Anatomy.) 
Thoracic Duct. 
The Thoracic Duct (Fig. 423) conveys the great mass of the lymph and chyle 
into the blood. It is the common trunk of all the lymphatic vessels of the body, 
excepting those of the right side of the head, neck, and thorax, and right upper 
extremity, the right lung, right side of the heart, and the convex surface of the 
liver. It varies in length from fifteen to eighteen inches in the adult, and extends 
from the second lumbar vertebra to the root of the neck. It commences in the 
abdomen by a triangular dilatation, the receptaculum chyli (reservoir or cistern of 
Pecquetf which is situated upon the front of the body of the second lumbar vertebra, 
to the right side and behind the aorta, by the side of the right crus of the dia- 
phragm. It ascends into the thorax through the aortic opening in the diaphragm, 
lying to the right of the aorta and is placed in the posterior mediastinum in front 
of the vertebral column, lying between the aorta and vena azygos major. Oppo- 
site the fourth dorsal vertebra it inclines toward the left side and ascends behind the 
arch of the aorta, on the left side of the oesophagus and behind the first portion of 
the left subclavian artery, to the upper orifice of the thorax. Opposite the upper 
border of the seventh cervical vertebra it curves downward above the subclavian 
artery and in front of the Scalenus anticus muscle so as to form an arch, and termi- 
nates near the angle of junction of the left internal jugular and subclavian veins. 
The thoracic duct at its commencement is about equal in size to the diameter of a 
goose-quill, diminishes considerably in its calibre in the middle of the thorax, and 
is again dilated just before its termination. It is generally flexuous in its course, 
and constricted at intervals so as to present a varicose appearance. The thoracic 
duct not unfrequently divides in the middle of its course into two branches of 
unequal size which soon reunite, or into several branches which form a plexiform 
interlacement. It occasionally bifurcates at its upper part into two branches, of 
which the one on the left side terminates in the usual manner, while that on 
the right opens into the right subclavian vein in connection with the right lymph- 
atic duct. The thoracic duct has numerous valves throughout its whole course, but 
they are more numerous in the upper than in the lower part: at its termination it 
is provided with a pair of valves, the free borders of which are turned toward the 
vein, so as to prevent the passage of venous blood into the duct. 
Tributaries.-The thoracic duct at its commencement receives four or five large 
trunks from the abdominal lymphatic glands, and also the trunk of the lacteal ves- 
sels. Within the thorax it is joined by the lymphatic vessels from the left half of 
the wall of the thoracic cavity, the lymphatics from the sternal and intercostal 
glands, those of the left lung, left side of the heart, trachea, and oesophagus; and 
just before its termination its receives the lymphatics of the left side of the head 
and neck and left upper extremity. 
Structure (Fig. 65, p. 85).-The thoracic duct is composed of three coats, which 
differ in some respects from those of the lymphatic vessels. The internal coat consists 
of a layer of endothelium, consisting of a single layer of flattened lanceolate cells 
with serrated borders ; of a subendothelial layer similar to that found in the arte- 
ries ; and an elastic fibrous coat, the fibres of which run in a longitudinal direction. 
The middle coat consists of a longitudinal layer of white connective tissue with 640 
THE LYMPHATICS. 
elastic fibres, external to which are several laminae of muscular tissue, the fibres of 
which are for the most part disposed transversely, but some are oblique or longitu- 
dinal and intermixed with elastic 
fibres. The external coat is com- 
posed of areolar tissue, with elastic 
fibres and isolated fasciculi of mus- 
cular fibres. 
The Right Lymphatic Duct 
is a short trunk, about an inch in 
length and a line or a line and a 
half in diameter, which receives 
the lymph from the right side of 
the head and neck, the right up- 
per extremity, the right side of 
the thorax, the right lung, and 
right side of the heart, and from 
part of the convex surface of the 
liver, and terminates at the angle 
of union of the right subclavian 
and right internal jugular veins. 
Its orifice is guarded by two semi- 
lunar valves which prevent the 
entrance of blood from the veins. 
Fig. 423. 
Rig/if 
Li zz mpfiaMo 
Uuct s 
Intercostal 
Glands 
Lymphatics of the Head, 
Face, and Neck. 
The Superficial Lymphatic 
. Glands of the Head (Fig. 424) 
are of small size, few in number, 
and confined to its posterior region. 
They are the occipital, placed at the 
back of the head along the attach- 
ment of the Occipito-frontalis ; and 
the posterior auricular, near the 
upper end of the Sterno-mastoid. 
These glands are affected in cuta- 
neous eruptions and other diseases 
of the scalp. In the face the super- 
ficial lymphatic glands are more nu- 
merous : they are the parotid, some 
of which are superficial and others 
deeply placed in the substance of 
the parotid gland; the zygomatic, 
situated under the zygoma; the 
buccal, on the surface of the Bucci- 
nator muscle; and the submaxillary, 
the largest, beneath the body of the 
lower jaw. 
The Superficial Lymphatics 
of the Head are divided into an 
anterior and a posterior set, which 
follow the course of the temporal and occipital vessels. The temporal set accom- 
pany the temporal artery in front of the ear to the parotid lymphatic glands, from 
which they proceed to the lymphatic glands of the neck. The occipital set follow 
the course of the occipital artery, descend to the occipital and posterior auricular 
lymphatic glands, and from thence join the cervical glands. 
Lazalar Glands 
The Thoracic and Right Lymphatic Duct. LYMPHATICS OF THE HEAD, FACE, AND NECK. 
641 
The Superficial Lymphatics of the Face are more numerous than those of 
the head, and commence over its entire surface. Those from the frontal region 
accompany the frontal vessels: they then pass obliquely across the face, running 
with the facial vein, pass through the buccal glands on the surface of the Bucci- 
nator muscle, and join the submaxillary lymphatic glands. The latter receive the 
lymphatic vessels from the lips, and are often found enlarged in cases of malignant 
disease of those parts. 
The Deep Lymphatics of the Face are derived from the pituitary membrane 
of the nose, the mucous membrane of the mouth and pharynx, and the contents of 
Fig. 424. 
The Superficial Lymphatics and Glands of the Head, Face, and Neck. 
the temporal and orbital fossae: they accompany the branches of the internal max- 
illary artery, and terminate in the deep parotid and cervical lymphatic glands. 
The Deep Lymphatics of the Cranium consist of two sets, the meningeal and 
cerebral. The meningeal lymphatics accompany the meningeal vessels, escape 
through foramina at the base of the skull, and join the deep cervical lymphatic 
glands. The cerebral lymphatics are described by Eshmann as being situated 
between the arachnoid and pia mater, as well as in the choroid plexuses of the lat- 
eral ventricles: they accompany the trunks of the carotid and vertebral arteries, 
and probably pass through foramina at the base of the skull, to terminate in the 
deep cervical glands. They have not at present been demonstrated in the dura 
mater or in the substance of the brain. 642 
THE LYMPHATICS. 
The Lymphatic Glands of the Neck are divided into two sets, superficial and 
deep. 
The superficial cervical glands (Fig. 424) are placed in the course of the 
external jugular vein between the Platysma and deep fascia. They are most 
numerous at the root of the neck, in the triangular interval between the clavicle, 
the Sterno-mastoid, and the Trapezius, where they are continuous with the axillary 
glands. A few small glands are also found on the front and sides of the larynx. 
The deep cervical glands (Fig. 425) are numerous and of large size ; they form 
an uninterrupted chain along the sheath of the carotid artery and internal jugular 
vein, lying by the side of the pharynx, oesophagus, and trachea, and extending 
Fig. 425. 
The Deep Lymphatics and Glands of the Neck and Thorax. 
from the base of the skull to the thorax, where they communicate with the lym- 
phatic glands in that cavity. 
The superficial and deep cervical lymphatics are a continuation of those 
already described on the cranium and face. After traversing the glands in those 
regions they pass through the chain of glands which lie along the sheath of the 
carotid vessels, being joined by the lymphatics from the pharynx, oesophagus, 
larynx, trachea, and thyroid gland. At the lower part of the neck, after receiving 
some lymphatics from the thorax, they unite into a single trunk, which terminates 
on the left side in the thoracic duct; on the right side, in the right lymphatic duct. LYMPHATICS OF THE UPPER EXTREMITY. 
643 
Lymphatics of the Upper Extremity. 
The Lymphatic Glands of the Upper Extremity (Fig. 426) may be sub- 
divided into two sets, superficial and deep. 
The superficial lymphatic glands are few and of small size. There are 
occasionally two or three in front of the elbow, and one or two above the internal 
Fig. 426. 
AjcillaTif 
condyle of the humerus, near the basilic vein. [These are sometimes enlarged in 
syphilis.] 
The deep lymphatic glands are also few in number. In the forearm a few 
small ones are occasionally found in the course of the radial and ulnar vessels; and 
in the arm there is a chain of small glands along the inner side of the brachial 
artery. 
The axillary glands are of large size and usually ten or twelve in number. A 
chain of these glands surrounds the axillary vessels imbedded in a quantity of loose 
areolar tissue: they receive the lymphatic vessels from the arm; others are dis- 
The Superficial Lymphatics and Glands of the Upper Extremity. 644 
THE LYMPHATICS. 
persed in the areolar tissue of the axilla; the remainder are arranged in two series, 
a small chain running along the lower border of the Pectoralis major as far as the 
mammary gland, receiving the lymphatics from the front of the chest and mamma; 
and others are placed along the lower margin of the posterior wall of the axilla, 
which receive the lymphatics from the integument of the back. Two or three sub- 
clavian lymphatic glands are placed immediately beneath the clavicle ; it is through 
these that the axillary and deep cervical glands communicate with each other. In 
malignant diseases, tumors, or other affections implicating the upper part of the 
back and shoulder, the front of the chest and mamma, the upper part of the front 
and side of the abdomen, or the hand, forearm, and arm, the axillary glands are 
liable to be found enlarged. [These glands have assumed greater importance with 
the recent practice of cleaning out the entire axilla in cancer of the breast, etc., and 
should therefore be carefully examined.] 
The superficial lymphatics of the upper extremity commence on the fingers, 
two vessels running along each side of each finger, one on the palmar and the other 
on the dorsal surface. Those on the palmar surface form an arch in the palm of 
the hand from which are derived two sets of vessels, which pass up the forearm, 
taking the course of the subcutaneous veins. The lymphatics from the dorsal sur- 
face of the fingers form a plexus on the back of the hand, and, winding around the 
inner and outer borders of the forearm, unite with those in front. Those from the 
inner border of the hand accompany the ulnar veins along the inner side of the 
forearm to the bend of the elbow, where they join with some lymphatics from the 
outer side of the forearm; they then follow the course of the basilic vein, com- 
municate with the glands immediately above the elbow, and terminate in the axil- 
lary glands, joining with the deep lymphatics. The superficial lymphatics from the 
outer and back part of the hand accompany the radial veins to the bend of the 
elbow. They are less numerous than the preceding. At the bend of the elbow the 
greater number join the basilic group; the rest ascend with the cephalic vein on 
the outer side of the arm, some crossing the upper part of the Biceps obliquely, to 
terminate in the axillary glands, while one or two accompany the cephalic vein in 
the cellular interval between the Pectoralis major and Deltoid and enter the sub- 
clavian lymphatic glands. 
The deep lymphatics of the upper extremity accompany the deep blood-vessels. 
In the forearm they consist of four sets, corresponding with the radial, ulnar, and 
interosseous arteries; they pass through the glands occasionally found in the course 
of those vessels, and communicate at intervals with the superficial lymphatics. In 
their course upward some of them pass through the glands which lie upon the bra- 
chial artery; they then enter the axillary and subclavian glands, and at the root 
of the neck terminate on the left side in the thoracic duct, and on the right side in 
the right lymphatic duct. 
Lymphatics of the Lower Extremity. 
The Lymphatic Glands of the Lower Extremity may be subdivided into two 
sets, superficial and deep; the former are confined to the inguinal region. 
The superficial inguinal glands, placed immediately beneath the integument, 
are of large size and vary from eight to ten in number. They are divisible into 
two groups: a superior, disposed irregularly along Poupart's ligament, which receive 
the lymphatic vessels from the integument of the scrotum, penis [labia majora and 
minora and clitoris], parietes of the abdomen, perineal and gluteal regions, and the 
mucous membrane of the urethra; and an inferior group, which surround the saphe- 
nous opening in the fascia lata, a few being sometimes continued along the saphenous 
vein to a variable extent. The latter receive the superficial lymphatic vessels from 
the lower extremity. These glands frequently become enlarged in diseases impli- 
cating the parts from which their lymphatics originate. [It is very important to 
distinguish the two sets accurately, as enlargement of one set or of the other points 
to wholly different sources and regions of disease.] Thus in malignant or syphilitic LYMPHATICS OF THE LOWER EXTREMITY. 
645 
affections of the prepuce and penis or of 
the labia majora in the female, in cancer 
scroti, in abscess in the perineum, or in 
any other disease affecting the integument 
and superficial structures in those parts 
or the subumbilical part of the abdominal 
wall or gluteal region, the upper chain of 
glands is almost invariably enlarged, the 
lower chain being implicated in diseases 
affecting the lower limb. 
The deep lymphatic glands are the 
anterior tibial, deep popliteal, deep in- 
guinal, gluteal, and ischiatic. 
The anterior tibial gland is not con- 
stant in its existence. It is generally found 
by the side of the anterior tibial artery 
upon the interosseous membrane at the 
upper part of the leg. Occasionally, two 
glands are found in this situation. 
The deep popliteal glands, four or 
five in number, are of small size; they 
surround the popliteal vessels, imbedded 
in the cellular tissue and fat of the pop- 
liteal space. 
The deep inguinal glands are placed 
beneath the deep fascia around the femoral 
artery and vein. They are of small size, 
and communicate with the superficial in- 
guinal glands through the saphenous 
opening. 
The gluteal and ischiatic glands are 
placed, the former above, the latter below, 
the Pyriformis muscle, resting on their cor- 
responding vessels as they pass through the 
great sacro-sciatic foramen. 
The Lymphatics of the Lower Ex- 
tremity, like the veins, may be divided 
into two sets, superficial and deep. 
The superficial lymphatics are placed 
beneath the integument in the superficial 
fascia, and are divisible into two groups: 
an internal group, which follow the course 
of the internal saphenous vein ; and an ex- 
ternal group, which accompany the external 
saphenous. The internal group, the larger, 
commence on the inner side and dorsum 
of the foot; they pass, some in front and 
some behind the inner ankle, run up the 
leg with the internal saphenous vein, pass 
with it behind the inner condyle of the 
femur, and accompany it to the groin, 
where they terminate in the group of in- 
guinal glands which surround the saphe- 
nous opening. Some of the efferent ves- 
sels from these glands pierce the cribri- 
form fascia and sheath of the femoral ves- 
sels, and terminate in a lymphatic gland 
S u,pe'FftoictT' 
InguMn-O/l | 
Cl<i,nds | 
Fig. 427. The Superficial Lymphatics and Glands 
of the Lower Extremity. 646 
THE LYMPHATICS. 
contained in the femoral canal, thus establishing a communication between the lymph- 
atics of the lower extremity and those of the trunk; others pierce the fascia lata and 
join the deep inguinal glands. The external group arise from the outer side of the 
foot, ascend in front of the leg, and, just below the knee, cross the tibia from with- 
out inward, to join the lymphatics on the inner side of the thigh. Others commence 
on the outer side of the foot, pass behind the outer malleolus, and accompany the 
external saphenous vein along the back of the leg, where they enter the popliteal 
glands. 
The deep lymphatics of the lower extremity are few in number and accompany 
the deep blood-vessels. In the leg they consist of three sets, the anterior tibial, 
peroneal, and posterior tibial, which accompany the corresponding blood-vessels, two 
or three to each artery; they ascend with the blood-vessels and entei' the lymphatic 
glands in the popliteal space; the efferent vessels from these glands accompany the 
femoral vein and join the deep inguinal glands; from these the vessels pass beneath 
Poupart's ligament and communicate with the chain of glands surrounding the exter- 
nal iliac vessels. 
The deep lymphatics of the gluteal and ischiatic regions follow the course of 
the blood-vessels, and join the gluteal and ischiatic glands at the great sacro- 
sciatic foramen. 
Lymphatics of the Pelvis and Abdomen. 
The Deep Lymphatic Glands in the Pelvis are the external iliac, the internal 
iliac, and the sacral. Those of the abdomen are the lumbar glands. 
The external iliac glands form an uninterrupted chain round the external iliac 
vessels, three being placed round the commencement of the vessels just behind the 
crural arch. They communicate below with the femoral lymphatics and above with 
the lumbar glands. 
The internal iliac glands surround the internal iliac vessels; they receive the 
lymphatics corresponding to the branches of the internal iliac artery and communi- 
cate with the lumbar glands. 
The sacral glands occupy the sides of the anterior surface of the sacrum, some 
being situated in the meso-rectal fold. These and the internal iliac glands are affected 
in malignant disease of the bladder, rectum, or uterus. 
The lumbar glands are very numerous; they are situated on the front of the 
lumbar vertebras, surrounding the common iliac vessels, the aorta, and vena cava; 
they receive the lymphatic vessels from the lower extremities and pelvis, as well as 
from the testes and some of the abdominal viscera; the efferent vessels from these 
glands unite into a few large trunks, which, with the lacteals, form the commence- 
ment of the thoracic duct. In addition to these there are a few small lateral lumbar 
glands which lie between the transverse processes of the vertebrae, behind the Psoas 
muscle, and receive lymphatics from the back. In some cases of malignant disease 
these glands become enormously enlarged, completely surrounding the aorta and 
vena cava, and occasionally greatly contracting the calibre of those vessels. In all 
cases of malignant disease of the testis and in malignant disease of the lower limb, 
before any operation is attempted, careful examination of the abdomen should be 
made in order to ascertain if any enlargement exists; and if any should be detected 
all operative measures should be avoided as fruitless. 
The Lymphatics of the Pelvis and Abdomen may be divided into two sets, 
superficial and deep. 
The superficial lymphatics of the walls of the abdomen and pelvis follow 
the course of the superficial blood-vessels. Those derived from the integument of 
the lower part of the abdomen below the umbilicus follow the course of the super- 
ficial epigastric vessels, and converge to the superior group of the superficial 
inguinal glands; the deep set accompany the deep epigastric vessels and commu- 
nicate with the external iliac glands. The superficial lymphatics from the sides of 
the lumbar part of the abdominal wall wind round the crest of the ilium, accom- LYMPHATICS OF THE PELVIS AND ABDOMEN. 
647 
panying the superficial circumflex iliac vessels, to join the superior group of the 
superficial inguinal glands ; the greater number, however, run backward along with 
the ilio-lumbar and lumbar vessels, to join the lateral lumbar glands. 
The superficial lymphatics of the gluteal region turn horizontally round 
the outer side of the nates and join the superficial inguinal glands. 
Fig. 428. 
Glands 
_ Sacral Glands 
„ Interna/ 
Iliac Glands 
External 
Iliac Glands 
7 
J.rvjuinaL 
Glands 
Deep Lymphatics 
of Penis 
The Deep Lymphatic Vessels and Glands of the Abdomen and Pelvis, 
The superficial lymphatics of the scrotum and perineum follow the course 
of the external pudic vessels and terminate in the superficial inguinal glands. 
The superficial lymphatics of the penis occupy the sides and dorsum of the 
organ, the latter receiving the lymphatics from the skin covering the glans penis; 
they all converge to the upper chain of the superficial inguinal glands. The deep 
lymphatic vessels of the penis follow the course of the internal pudic vessels and 
join the internal iliac glands. 648 
THE LYMPHATICS. 
In the female the lymphatic vessels of the mucous membrane of the labia, 
nymphae, and clitoris terminate in the upper chain of the inguinal glands. 
The deep lymphatics of the pelvis and abdomen take the course of the 
principal blood-vessels. Those of the parietes of the pelvis, which accompany the 
gluteal, ischiatic, and obturator vessels, follow the course of the internal iliac artery, 
and ultimately join the lumbar lymphatics. 
The efferent vessels from the inguinal glands enter the pelvis beneath Poupart's 
ligament, where they lie in close relation with the femoral vein ; they then pass 
through the chain of glands surrounding the external iliac vessels, and finally ter- 
minate in the lumbar glands. They receive the deep epigastric and circumflex iliac 
lymphatics. 
The lymphatics of the bladder arise from the entire surface of the organ / 
the greater number run beneath the peritoneum on its posterior surface, and, after 
passing through the lymphatic glands in that situation, join with the lymphatics 
from the prostate and vesiculae seminales and enter the internal iliac glands. 
The lymphatics of the rectum are of large size; after passing through some 
small glands that lie upon its outer wall and in the mesorectum they pass to the 
sacral glands. 
The lymphatics of the uterus consist of two sets, superficial and deep, the 
former being placed beneath the peritoneum, the latter in the substance of the 
organ. The lymphatics of the cervix uteri, together with those from the vagina, 
enter the internal iliac and sacral glands ; those from the body and fundus of the 
uterus pass outward in the broad ligaments, and, being joined by the lymphatics 
from the ovaries, broad ligaments, and Fallopian tubes, ascend with the ovarian 
vessels to open into the lumbar glands. In the unimpregnated uterus they are 
small, but during gestation they become very greatly enlarged. 
The lymphatics of the testicle consist of two sets, superficial and deep: the 
former commence on the surface of the tunica vaginalis, the latter in the epididy- 
mis and body of the testis. They form several large trunks, which ascend with 
the spermatic cord, and, accompanying the spermatic vessels into the abdomen, 
open into the lumbar glands, hence the enlargement of these glands in malignant 
disease of the testis. 
The lymphatics of the kidney arise on the surface and also in the interior of 
the organ; they join at the hilum, and, after receiving the lymphatic vessels from 
the ureter and suprarenal capsules, open into the lumbar glands. 
The lymphatics of the liver are divisible into two sets, superficial and deep. 
The former arise in the subperitoneal areolar tissue over the entire surface of the 
organ. Those on the convex surface may be divided into four groups: 1, those 
which pass from behind forward, consisting of three or four branches, which ascend 
in the longitudinal ligament and unite to form a single trunk, which passes up 
between the fibres of the diaphragm, behind the ensiform cartilage, to enter the 
anterior mediastinal glands, and finally ascends to the root of the neck, to termi- 
nate in the right lymphatic duct; 2, another group, which also incline from behind 
forward, are reflected over the anterior margin of the liver to its under surface, and 
from thence pass along the longitudinal fissure to the glands in the gastro-hepatic 
omentum ; 3, a third group incline outward to the right lateral ligament, and, unit- 
ing into one or two large trunks, pierce the diaphragm, and run along its upper 
surface to enter the anterior mediastinal glands; or, instead of entering the thorax, 
turn inward across the crus of the diaphragm and open into the commencement of 
the thoracic duct; 4, the fourth group incline outward from the surface of the left 
lobe of the liver to the left lateral ligament, pierce the diaphragm, and, passing 
forward, terminate in the glands in the anterior mediastinum. 
The superficial lymphatics on the under surface of the liver are divided into 
three sets: 1, those on the right side of the gall-bladder enter the lumbar glands; 
2, those surrounding the gall-bladder form a remarkable plexus: they accompany 
the hepatic vessels and open into the glands in the gastro-hepatic omentum ; 3, those 
1 Curnow states that they are confined to the base of the organ. THE LYMPHATIC SYSTEM OF THE INTESTINES. 
649 
on the left of the gall-bladder pass to the oesophageal glands and to the glands which 
are situated along the lesser curvature of the stomach. 
The deep lymphatics accompany the branches of the portal vein and the hepatic 
artery and duct through the substance of the liver; passing out at the transverse 
fissure, they enter the lymphatic glands along the lesser curvature of the stomach 
and behind the pancreas, or join with one of the lacteal vessels previous to its ter- 
mination in the thoracic duct. 
The lymphatic glands of the stomach are of small size; they are placed along 
the lesser and greater curvatures, some within the gastro-splenic omentum, whilst 
others surround the cardiac and pyloric orifices. 
The lymphatics of the stomach consist of two sets, superficial and deep, the 
former originating in the subserous, and the latter in the submucous-coat. They 
follow the course of the blood-vessels, and may consequently be arranged into three 
groups. The first group accompany the gastric vessels along the lesser curvature, 
receiving branches from both surfaces of the organ, and pass to the glands around 
the pylorus. The second group pass from the great end of the stomach, accompany- 
ing the vasa brevia, and enter the splenic lymphatic glands. The third group run 
along the greater curvature with the right gastro-epiploic vessels, and terminate at 
the root of the mesentery in one of the principal lacteal vessels. 
The lymphatic glands of the spleen occupy the hilum. Its lymphatic vessels 
consist of two sets, superficial and deep; the former are placed beneath its peritoneal 
covering, the latter in the substance of the organ: they accompany the blood-vessels, 
passing through a series of small glands, and after receiving the lymphatics from 
the pancreas ultimately pass into the thoracic duct. 
The Lymphatic System of the Intestines. 
The lymphatic glands of the small intestine are placed between the layers 
of the mesentery, occupying the meshes formed by the superior mesenteric vessels, 
and hence called mesenteric glands. They vary in number from a hundred to a 
hundred and fifty, and in size from that of a pea to that of a small almond. These 
glands are most numerous and largest above near the duodenum, and below opposite 
the termination of the ileum in the colon. This latter group becomes enlarged and 
infiltrated with deposit in cases of fever accompanied with ulceration of the intestines. 
The lymphatic glands of the large intestine are much less numerous than the 
mesenteric glands; they are situated along the vascular arches formed by the arteries 
previous to their distribution, and even sometimes upon the intestine itself. They 
are fewest in number along the transverse colon, where they form an uninterrupted 
chain with the mesenteric glands. 
The lymphatics of the small intestine are called lacteals, from the milk-white 
fluid they usually contain. They consist of two sets, superficial and deep: the former 
lie between the layers of the muscular coat and between the muscular and peritoneal 
coats, taking a longitudinal course along the outer side of the intestine; the latter 
occupy the submucous tissue, and course transversely around the intestine, accom- 
panied by the branches of the mesenteric vessels: they pass between the layers of 
the mesentery, enter the mesenteric glands, and finally unite to form two or three 
large trunks which terminate in the thoracic duct. 
The lymphatics of the large intestine consist of two sets: those of the caecum, 
ascending and transverse colon, which, after passing through their proper glands, 
enter the mesenteric glands; and those of the descending colon and rectum, which 
pass to the lumbar glands. 
The Lymphatics of the Thorax. 
The deep lymphatic glands of the thorax are the intercostal, internal mam- 
mary, anterior mediastinal, and posterior mediastinal. 
The intercostal glands are small, irregular in number, and situated on each 650 
THE LYMPHATICS. 
side of the spine near the costo-vertebral articulations, some being placed between 
the two planes of Intercostal muscles. 
The internal mammary glands are placed at the anterior extremity of each 
intercostal space by the side of the internal mammary vessels. 
The anterior mediastinal glands are placed in the loose areolar tissue of the 
anterior mediastinum, some lying upon the Diaphragm in front of the pericardium, 
and others around the great vessels at the base of the heart. 
The posterior mediastinal glands are situated in the areolar tissue in the poste- 
rior mediastinum, forming a continuous chain by the side of the aorta and oesopha- 
gus ; they communicate on each side with the intercostal, below with the lumbar, 
and above with the deep cervical glands. 
The superficial lymphatics of the front of the thorax run across the great 
Pectoral muscle, and those on the back part of this cavity lie upon the Trapezius 
and Latissimus dorsi; they all converge to the axillary glands. The lymphatics 
from the greater part of the mammary gland pass outward to the lower border of the 
Pectoralis major muscle, where they enter a chain of small glands situated in the 
axillary space along the lower border of its anterior boundary. Some few lym- 
phatics from the inner side of the mammary gland pass through the intercostal 
spaces to reach the anterior mediastinal glands. 
The deep lymphatics of the thorax are the intercostal, internal mammary, and 
diaphragmatic. 
The intercostal lymphatics follow the course of the intercostal vessels, receiv- 
ing lymphatics from the intercostal muscles and pleura; they pass backward to the 
spine, and unite with lymphatics from the back part of the thorax and spinal canal. 
After traversing the intercostal glands they incline down the spine and terminate in 
the thoracic duct. 
The internal mammary lymphatics follow the course of the internal mammary 
vessels; they commence in the muscles of the abdomen above the umbilicus, com- 
municating with the epigastric lymphatics, ascend between the fibres of the Dia- 
phragm at its attachment to the ensiform appendix, and in their course behind the 
costal cartilages are joined by the intercostal lymphatics; they terminate on the 
right side in the right lymphatic duct, on the left side in the thoracic duct. 
The lymphatics of the Diaphragm follow the course of their corresponding 
vessels, and terminate, some in front in the anterior mediastinal and internal mam- 
mary glands, some behind in the intercostal and posterior mediastinal lymphatics. 
The bronchial glands are situated around the bifurcation of the trachea and roots 
of the lungs. They are ten or twelve in number, the largest being placed opposite 
the bifurcation of the trachea, the smallest round the bronchi, and their primary 
divisions for some little distance within the substance of the lungs. In infancy 
they present the same appearance as lymphatic glands in other situations; in the 
adult they assume a brownish tinge, and in old age a deep-black color. Occasionally 
they become sufficiently enlarged to compress and narrow the canal of the bronchi, 
and they are often the seat of tubercle or cretaceous deposits. 
The lymphatics of the lung consist of two sets, superficial and deep: the former 
are placed beneath the pleura, forming a minute plexus which covers the outer sur- 
face of the lung; the latter accompany the blood-vessels and run along the bronchi: 
they both terminate at the root of the lungs in the bronchial glands. The efferent 
vessels from these glands, two or three in number, ascend upon the trachea to the 
root of the neck, traverse the tracheal and oesophageal glands, and terminate on the 
left side in the thoracic duct and on the right side in the right lymphatic duct. 
The cardiac lymphatics consist of two sets, superficial and deep: the former 
arise in the subserous areolar tissue of the surface, and the latter in the deeper tis- 
sues of-the heart. They follow the course of the coronary vessels : those of the right 
side unite into a trunk at the root of the aorta, which, ascending across the arch of 
that vessel, passes backward to the trachea, upon which it ascends, to terminate at 
the root of the neck in the right lymphatic duct. Those of the left side unite into 
a single vessel at the base of the heart, which, passing along the pulmonary artery THE LYMPHATICS OF THE THORAX. 
651 
and traversing some glands at the root of the aorta, ascends on the trachea to termi- 
nate in the thoracic duct. 
The thymic lymphatics arise from the spinal surface of the thymus gland and 
terminate on each side in the internal jugular veins. 
The thyroid lymphatics arise from either lateral lobe of this organ; they con- 
verge to form a short trunk, which terminates on the right side in the right lym- 
phatic duct, on the left side in the thoracic duct. 
The lymphatics of the oesophag-us form a plexus around that tube, traverse the 
glands in the posterior mediastinum, and, after communicating with the pulmonary 
lymphatic vessels near the roots of the lungs, terminate in the thoracic duct. The Nervous System. 
THE Nervous System is composed-1, of a series of large centres of nerve-mat- 
ter, called, collectively, the cerebrospinal centre or axis ; 2, of smaller centres, 
termed ganglia; 3, of nerves, connected either with the cerebro-spinal axis or the 
ganglia; and 4, of certain modifications of the peripheral terminations of the nerves 
forming the organs of the external senses. 
The Cerebro-spinal Centre consists of two parts, the spinal cord and the enceph- 
alon : the latter may be subdivided into the cerebrum, the cerebellum, the pons 
Varolii, and the medulla oblongata. 
Dissection.-To dissect the cord and its membranes it will be necessary to lay open the whole 
length of the spinal canal. For this purpose the muscles must be separated from the vertebral 
grooves, so as to expose the spinous processes and laminae of the vertebrae, and the latter must 
be sawn through on each side, close to the roots of the transverse processes, from the third or 
fourth cervical vertebra above to the sacrum below. The vertebral arches having been displaced 
by means of a chisel and the separate fragments removed, the dura mater will be exposed, cov- 
ered by a plexus of veins and a quantity of loose areolar tissue, often infiltrated with serous fluid. 
The arches of the upper vertebrae are best divided by means of a strong pair of cutting bone- 
forceps. 
THE SPINAL CORD AND ITS MEMBRANES. 
Membranes of the Cord. 
The membranes which envelop the spinal cord are three in number. The most 
external is the dura mater, a strong fibrous membrane which forms a loose sheath 
around the cord. The most internal is the pia mater, a cellulo-vascular membrane 
which closely invests the entire surface of the cord. Between the two is the 
arachnoid membrane, an intermediate structure which envelops the cord and 
is connected to the pia mater by slender filaments of connective tissue. 
The Dura Mater of the cord, continuous with that which invests the brain, is a 
loose sheath which surrounds the cord, and is separated from the bony walls of the 
spinal canal by a quantity of loose areolar adipose tissue and a plexus of veins. It 
is attached to the circumference of the foramen magnum and to the posterior com- 
mon ligament throughout the whole length of the spinal canal by fibrous slips, and 
extends below as far as the top of the sacrum; but beyond this point it is imper- 
vious, being continued in the form of a slender cord to the back of the coccyx, 
where it blends with the periosteum. This sheath is much larger than is necessary 
for its contents, and its size is greater in the cervical and lumbar regions than in the 
dorsal. Its inner surface is smooth, covered by a layer of polygonal cells; and on 
each side may be seen the double openings which transmit the two roots of the cor- 
responding spinal nerve, the fibrous layer of the dura mater being continued in the 
form of a tubular prolongation on them as they issue from these apertures. These 
prolongations of the dura mater are short in the upper part of the spine, but become 
gradually longer below, forming a number of tubes of fibrous membrane which enclose 
the sacral nerves and are contained in the spinal canal. 
The chief peculiarities of the dura mater of the cord, as compared with that 
investing the brain, are the following: 
The dura mater of the cord is not adherent to the bones of the spinal canal, 
which have an independent periosteum. 
It does not send partitions into the fissures of the cord, as in the brain. 
Its fibrous laminae do not separate to form venous sinuses, as in the brain. 
Structure.-The dura mater consists of white fibrous and elastic tissue arranged 
652 MEMBRANES OF THE CORD. 
653 
in bands or lamellae which, for the most part, are parallel with one another. It is 
sparingly supplied with vessels, and some few nerves have been traced into it. 
The Arachnoid is exposed by slitting up the dura 
mater and reflecting that membrane to either side 
(Fig. 429). It is a thin, delicate, tubular membrane 
which invests the surface of the cord and is connected 
to the pia mater by slender filaments of connective tis- 
sue. Above it is continuous with the cerebral arach- 
noid ; on either side it is continued on the various 
nerves so as to form a sheath for them as they pass out- 
ward to the intervertebral foramina. The outer surface 
of the arachnoid is in contact with the inner surface of 
the dura mater, and the two are here and there con- 
nected together by isolated connective-tissue trabec- 
ulae, especially on the posterior surface of the cord. 
For the most part, however, the membranes are not 
connected together, and the interval between them is 
named the subdural space. The inner surface of the 
arachnoid is separated from the pia mater by a con- 
siderable interval, which is called the subarachnoidean 
space This space is largest at the lower part of the 
spinal canal, and encloses the mass of nerves which form 
the cauda equina. It contains an abundant serous secre- 
tion, the cerebro-spinal [or cephalo-rachidian\ fluid, and 
usually communicates with the general ventricular cavity 
of the brain by means of an opening in the pia mater at 
the inferior boundary of the fourth ventricle {foramen 
of Majendicf This secretion is sufficient in amount to 
expand the arachnoid membranes so as to completely fill up the whole of the space 
included in the dura mater. The subarachnoidean space is crossed at the back part 
of the cord by numerous fibrous bands which 
stretch from the arachnoid to the pia mater, es- 
pecially in the cervical region, and is partially 
subdivided by a longitudinal membranous parti- 
tion which serves to connect the arachnoid with 
the pia mater opposite the posterior median fis- 
sure. This partition is incomplete and cribriform 
in structure, consisting of bundles of white fibrous 
tissue interlacing with each other.2 [These spaces 
around the cord are really lymph-spaces.] 
Structure.-The arachnoid is a delicate mem- 
brane made up of closely-arranged parallel bun- 
dles of connective tissue, covered on the cuter or dural surface by one or two layers 
of endothelial cells. The inner surface is also covered with an endothelium, and 
gives off a spongy network of trabeculae of fibrous tissue, the surfaces of which are 
Fig. 429. 
The Spinal Cord and its Mem- 
branes. 
Fig. 430. 
zDura Mater 
/ARACHNOID 
Lig. Dentiou- 
LATUM 
Transverse Section of the Spinal Cord and 
its Membranes. 
Pia Mater 
1 [This mixture of Latin and Greek is an unfortunate barbarism of language, like "subdermal" 
for "hypodermic," but is probably too firmly intrenched to be dislodged. The proper term is 
" hypo-arachnoidean."] 
2 It will be noticed that this description of the arachnoid varies from that in former editions, 
which described this membrane as a closed sac, one layer of which, the visceral layer, ensheathed the 
cord, and the other, the parietal layer, was reflected over the inner surface of the dura mater. The 
space between the two layers was termed the " cavity of the arachnoid," and corresponded to the 
"subdural " space in the above description. Kolliker was the first to deny that the inner surface of 
the dura mater was covered by an outer layer of the arachnoid; he states that nothing is found here 
except epithelium, no trace of a special membrane existing. This view is now very generally 
adopted by anatomists, and appears to have derived additional confirmation from the investigations 
of Retzius and Axel Key, who state that the connection which was formerly described as taking 
place between the two layers of the arachnoid as they were prolonged in the form of a tubular sheath 
over the nerves does not exist. The same remark applies to the arachnoid membrane of the brain, 
which is no longer regarded as a closed sac. (See p. 663.) 654 
THE NERVOUS SYSTEM. 
covered with endothelium and which stretch across between the arachnoid and pia 
mater. This spongy tissue is named subarachnoid tissue (Retzius and Key). 
The Pia Mater of the cord is exposed on the removal of the arachnoid 
(Fig. 429). It covers the entire surface of the cord, to which it is very intimately 
adherent, forming its neurilemma, and sends a process downward into its anterior 
fissure, and another, extremely delicate, into the posterior fissure. It also forms a 
sheath for each of the filaments of the spinal nerves, and invests the nerves them- 
selves. A longitudinal fibrous band extends along the middle line on its anterior 
surface, called by Haller the linea splendens; and a somewhat similar band, the 
ligamentum denticulatum, is situated on each side. At the point where the cord 
terminates the pia mater becomes contracted, and is continued down as a long, slen- 
der filament {filum terminale), which descends through the centre of the mass of 
nerves forming the cauda equina, and is blended with the impervious sheath of 
dura mater on a level with the top of the sacral canal. It assists in maintaining 
the cord in its position during the movements of the trunk, and is from this cir- 
cumstance called the central ligament of the spinal cord. It contains a little gray 
nervous substance which may be traced for some distance into its upper part, and is 
accompanied by a small artery and vein. 
Structure.-The pia mater of the cord is less vascular in structure, but 
thicker and denser than the pia mater of the brain, with which it is continuous. 
It is composed of bundles of connective-tissue fibres arranged for the most part 
longitudinally. It is usually described as consisting of two layers, between which 
are a number of lymphatic spaces, which communicate with the subarachnoid space 
and in which the vessels ramify. It is also supplied with nerves, which are derived 
from the sympathetic and from the posterior roots of the spinal nerves. At the 
upper part of the cord the pia mater presents a grayish, mottled tint, which is 
owing to yellow or brown pigment-cells scattered among the elastic fibres. 
The Ligamentum Denticulatum (Fig. 429) is a narrow fibrous band situated on 
each side of the spinal cord throughout its entire length, and separating the ante- 
rior from the posterior roots of the spinal nerves, having received its name from 
the serrated appearance which it presents. Its inner border is continuous with the 
pia mater at the side of the cord. Its outer border presents a series of triangular, 
dentated serrations, the points of which are fixed at intervals to the dura mater. 
These serrations are about twenty in number on each side, the first being attached 
to the dura mater, opposite the margin of the foramen magnum, between the ver- 
tebral artery and the hypoglossal nerve, and the last near the lower end of the cord. 
Its use is to support the cord in the fluid by which it is surrounded. 
The Spinal Cord. 
The Spinal Cord {medulla spinalis) is the cylindrical elongated part of the 
cerebro-spinal axis which is contained in the vertebral canal. Its length is usually 
about seventeen or eighteen inches, and its weight, when divested of its membranes 
and nerves, about one ounce and a half, its proportion to the encephalon being 
about 1 to 33. It does not nearly fill the canal in which it is contained, its 
investing membranes being separated from the surrounding walls by areolar tissue 
and a plexus of veins. It occupies, in the adult, the upper two-thirds of the ver- 
tebral canal, extending from the upper border of the atlas to the lower border of 
the body of the first lumbar vertebra, where it terminates in a slender filament of 
gray substance, which is continued for some distance into the filum terminale. In 
the foetus, before the third month, it extends to the bottom of the sacral canal, but 
after this period it gradually recedes from below, as the growth of the bones com- 
posing the canal is more rapid in proportion than that of the cord, so that in the 
child at birth the cord extends as far as the third lumbar vertebra. Its position 
varies also according to the degree of curvature of the spinal column, being raised 
somewhat in flexion of the spine. On examining its surface it presents a differ- 
ence in its diameter in different parts, being marked by two enlargements, an THE SPINAL CORD. 
655 
upper or cervical and a lower or lumbar. The cervical enlargement, which is the 
larger, extends from about the third cervical to the first or second dorsal vertebra: 
its greatest diameter is in the transverse direction, and it corresponds with the 
origin of the nerves which supply the upper extremities. The lower or lumbar 
enlargement is situated opposite the last two or three dorsal vertebrae, its greatest 
diameter being from before backward. It corresponds with the origin of the 
nerves which supply the lower extremities. In form the spinal cord is a flattened 
cylinder. It presents on its anterior surface, along the middle line, a longitudinal 
fissure, the anterior median fissure; and on its posterior surface another fissure, 
which also extends along the entire length of the cord, the posterior median fissure. 
These fissures serve to divide the cord into two symmetrical halves, which are 
united in the middle line, throughout their entire length, by a transverse band 
of nervous substance, the commissure. 
The Anterior Median Fissure is wider but of less depth than the posterior, 
extending into the cord for about one-third of its thickness, and is deepest at the 
lower part of the cord. It contains a prolongation from the pia mater, and its 
floor is formed by the anterior white commissure, which 
is perforated by numerous blood-vessels passing to the 
centre of the cord. 
The Posterior Median Fissure is not an actual 
fissure, as the space between the lateral halves of the 
posterior part of the cord is filled up by connective tis- 
sue and numerous blood-vessels, so that no actual hia- 
tus exists, and there is consequently no prolongation of 
the pia mater into it. It extends into the cord to about 
one half its depth, and its floor is formed by the pos- 
terior gray commissure. 
Lateral Fissures.-On either side of the anterior 
median fissure a linear series of foramina may be ob- 
served, indicating the points where the anterior roots 
of the spinal nerves emerge from the cord. This is 
called by some anatomists the antero-lateral fissure of the cord, although no actual 
fissure exists in this situation. And on either side of the posterior median fissure, 
along the line of attachment of the posterior roots of the nerves, a delicate fissure 
may be seen leading down to the gray matter, which approaches the surface in this 
situation ; this is called the postero-lateral fissure of the spinal cord. On the pos- 
terior surface of the spinal cord, on either side of the posterior median fissure, is a 
slight longitudinal furrow marking off two slender tracts, the posterior median col- 
umns. These are most distinct in the cervical region, but are stated by Foville to 
exist throughout the whole length of the cord. 
Columns of the Cord.-The fissures divide each half of the spinal cord into 
four columns: an anterior column, a lateral column, a posterior column, and a pos- 
terior median column. 
The anterior column includes all the portion of the cord between the anterior 
median fissure and the antero-lateral fissure from which the anterior roots of 
the nerves arise. It is continuous with the anterior pyramid of the medulla 
oblongata. 
The lateral column, the largest segment of the cord, includes all the portion 
between the antero- and postero-lateral fissures. It is continuous with the lateral 
column of the medulla. By some anatomists the anterior and lateral columns are 
included together under the name of the antero-lateral column, which forms rather 
more than two-thirds of the entire circumference of the cord. 
The posterior column is situated between the posterior median and postero-lateral 
fissures. It is continuous with the restiform body of the medulla. 
The posterior median column is that narrow segment of the cord which is seen 
on each side of the posterior median fissure, usually included with the preceding as 
the posterior column. 
Anter lor M.e<L tan Pies arc 
Anterior Lateral Pisa arc 
Fig. 431. 
Posterior 
Median 
Posterior 
Late-reel Pis sure 
Spinal Cord, side view-plan of the 
Fissures and Columns. 656 
THE NERVOUS SYSTEM. 
Structure of the Cord.-If a transverse section of the spinal cord be made, it 
will be seen to consist of white and gray nervous substance. The white matter is 
situated externally, and constitutes the greater part. The gray substance occupies 
the centre, and is sb arranged as to present on the surface of 
the section two crescentic masses placed one in each lateral half 
of the cord, united together by a transverse band of gray mat- 
ter, the gray commissure. Each crescentic mass has an ante- 
rior and posterior horn. The posterior horn is long and nar- 
row, and approaches the surface of the postero-lateral fissure, 
near which it presents a slight enlargement, the caput cornu .- 
from this it tapers to form the apex cornu, which at the surface 
of the cord becomes continuous with the fibres of the posterior 
roots of the spinal nerves. The anterior horn is short and 
thick, and does not quite reach the surface, but extends 
toward the point of attachment of the anterior roots of the 
nerves. Its margin presents a dentate or stellate appearance. 
Owing to the projections toward the surface of the anterior and 
posterior horns of the gray matter, each half of the cord is 
divided, more or less completely, into three columns, anterior, 
middle, and posterior, the anterior and middle being joined to 
form the antero-lateral column, as the anterior horn does not 
quite reach the surface. 
The gray commissure, which connects the two crescentic masses of gray matter, 
is separated from the bottom of the anterior median fissure by the anterior white 
commissure. It consists of transverse fibres, with a considerable quantity of neu- 
roglia between them. The fibres when they reach the lateral crescents diverge: 
some pass backward to the posterior roots, others spread out, at various angles, into 
the cervix cornu. The anterior [white] commissure is formed of fibres which pass 
horizontally between the gray matter of the anterior horn of one side and the ante- 
rior white column of the opposite side. 
Running through the gray commissure of the whole length of the cord is a min- 
ute canal which is barely visible to the naked eye in the human cord, but is pro- 
portionately larger in some of the lower Vertebrata. It is called the central canal 
(Fig. 433) and opens above into the fourth ventricle, and terminates below in a 
somewhat dilated extremity. [This "central canal " is the spinal analogue of the 
cerebral ventricles, and might well be called the "sixth ventricle " or the " ventri- 
cle of the cord."] 
The mode of arrangement of the gray matter, and its amount in proportion to 
the white, vary in different parts of the cord. Thus, the posterior horns are long 
and narrow in the cervical region, short and narrower in the dorsal, short but wider 
in the lumbar region. In the cervical region the crescentic portions are small, and 
the white matter more abundant than in any other region of the cord. In the dor- 
sal region the gray matter is least developed, the white matter being also small in 
quantity. In the lumbar region the gray matter is more abundant than in any 
other region of the cord. Toward the lower end of the cord the white matter grad- 
ually ceases. The crescentic portions of the gray matter soon blend into a single 
mass which forms the only constituent of the extreme point of the cord. 
Minute Anatomy of the Cord.-The cord consists of an outer part, composed 
of medullated nerve-fibres, which is the white substance, and of a central part, the 
gray matter, both supported in a peculiar kind of connective tissue called neuroglia. 
The neuroglia consists of a homogeneous transparent matrix of a network of very 
delicate fibrillae, and of small stellate or branched cells, the neuroglia-cells. 
In addition to forming a ground substance, in which the nerve-fibres, nerve-cells, 
and blood-vessels are imbedded, a considerable accumulation takes place in three 
situations: 1, on the surface of the cord, beneath the pia mater ; 2, around the 
central canal; and 3, in the posterior part of the posterior horn, forming the sub- 
stantia cinerea gelatinosa. 
Fig. 432. 
Opposite Middle of Cervical 
Region. 
Opposite Middle of Dorsal 
Region. 
Opposite Lumbar Region. 
Transverse Sections of 
the Cord. THE SPINAL CORD. 
657 
The white substance of the cord consists of medullated nerve-fibres, with blood- 
vessels and neuroglia. On transverse section of the white substance of the cord a 
very striking object is presented. It is seen to be studded all over with minute dots, 
surrounded by a white area, and this again by a dark circle (Fig. 438). This is due 
to the longitudinal medullated fibres seen on section. The dot is the axis-cylinder, 
the white area the substance of Schwann, and the dark circle the tubular membrane 
of the fibres, which seems to consist of several laminae. Externally, the neuroglia 
Fig. 433. 
Central canal 
[or " ventri- 
cle of the 
cord"J. 
Transverse Section through the Cervical Portion of the Spinal Cord of a Calf (magnified 40 diameters-Klein 
and Noble Smith) • w the white matter of the cord, subdivided by septa of connective tissue, s, extending 
from the pia mater to the gray matter, which is seen in the interior with its ganglion-coils. The dots around 
this show divided nerve-fibres, which exist, but are not shown, in the other parts of the white substance. 
The central canal is seen in the gray matter. 
is seen to form a delicate connective sheath around the outer surface of the cord imme- 
diately beneath the pia mater, from which numerous septa pass in to separate the 
respective bundles of fibres and extend between the individual nerve-fibres, acting 
as a supporting medium in which they are imbedded. Thus it will be seen that the 
greater bulk of the white matter of the cord is made up of longitudinal medullated 
fibres, which are arranged in groups forming the anterior, lateral, and posterior 
columns. 
There are, however, also oblique and transverse fibres in the white substance. 
These are principally found (1) at the bottom of the anterior median fissure, form- 658 
THE NERVOUS SYSTEM. 
ing the anterior commissure, the fibres passing from the gray matter of the anterior 
horn on one side to the white matter of the anterior column of the opposite side; 
(2) horizontal or oblique fibres passing from the roots of the nerves into the gray 
matter; and (3) fibres leaving the gray matter and pursuing a longer or shorter 
horizontal course between the bundles of longitudinal fibres with which many of 
them are continuous. 
The primary septa sent into the substance of the cord from the neuroglia on the 
surface are accompanied by prolongations of the pia mater, and pass in a radiating 
manner into the white substance and divide it up into a number of smaller portions 
or columns, which can be traced upward and are continuous with different columns 
Fig. 434. 
Fig. 435. 
Anterior Nerve Root 
PoslFMei* Fissu-re 
Cervix Coriiur 
Traci* 
Int'e:rm,e-cLio 
lot? 
Transverse Section of the Gray Substance of the Spinal 
Cord, near the middle of the clorsal region (magnified 13 
diameters-J. L. Clarke del.). 
Columns of the Cord. 
Posterior Nerve Root 
of the medulla oblongata. Thus, on either side of the anterior median fissure a 
portion of the anterior column is divided off as the direct pyramidal fasciculus 
(fasciculus of Tiirck), which can be traced upward in continuity with the non- 
decussating fibres of the pyramidal column of the medulla. The remainder of 
the anterior column of the cord forms the fundamental fasciculus, which is con- 
tinued into the deeper part of the medulla. The lateral column of the cord is 
divided into four tracts, the anterior division of which is called the anterior radic- 
ular zone, the peripheral portion of the posterior part the cerebellar column, and 
the internal part, next the gray substance, is termed the mixed lateral column, 
whilst an intermediate portion, between these last two, is the crossed portion of the 
pyramidal fasciculus, its fibres when traced upward forming the decussating portion 
of the anterior pyramidal tract of the medulla oblongata. The other three portions 
of the lateral column can be traced into the lateral tract of the medulla, the periph- 
eral fibres, or those forming the cerebellar column, passing through it to the cere- 
bellum. 
The posterior column of the cord is divided into two: the portion which lies 
next the posterior median fissure is called the column of Goll, and if traced upward 
is found to be continuous with the fasciculus gracilis of the medulla. The remain- 
der of the posterior column is called the cuneate fasciculus or Burdaclt s column, 
and is prolonged into the medulla under the same name. 
The gray substance of the cord occupies its central part in the shape of two 
crescentic horns joined together by a commissure. Each of these crescents has 
an anterior and a posterior cornu. 
The posterior horn consists of two parts-the caput cornu, or expanded extrem- 
ity of the horn (Fig. 436), round which is a lighter space or lamina of gelatinous THE SPINAL CORD. 
659 
substance; and the cervix cornu, or narrower portion, which connects it with the 
rest of the gray substance. 
The gelatinous substance is a peculiar accumulation of neuroglia (Klein), and 
has been named by Rolando the substantia cinerea gelatinosa. 
The anterior horn of the gray substance in the cervical and lumbar swellings, 
where it gives origin to the nerves of the extremities, is much larger than in 
any other region, and contains several distinct groups of large and variously 
shaped cells. 
The gray commissure is situated behind the white commissure, which separates 
it from the bottom of the anterior median fissure. In it is a central canal lined 
by epithelium, around which is a layer of neuroglia of considerable thickness, the 
central gray nucleus of Kblliker. The gray substance of the cord consists of-1, 
Fig. 436. 
Ant 
im* 
Fissure 
Transverse Section of the Gray Substance of the Spinal Cord, through the middle of the lumbar enlargement. 
On the left side of the figure groups of large cells are seen; on the right side the course of the fibres is 
shown without the cells (magnified 13 diameters-J. L. Clarke del.). 
nerve-fibres of variable but smaller average diameter than those of the columns; 
2, nerve-cells of various shapes and sizes, with from two to eight processes; 3, 
blood-vessels and connective tissue. 
The nerve-fibres of the gray matter are for the most part composed of a minute 
and dense network of minute fibrils, which is termed " Gerlach's nerve-network," 
intermingled with nerves of a larger size. This network is continuous with the 
medullated fibres of the posterior nerve-roots on the one hand (Deiters), and with 
the branched processes of the ganglion-cells on the other (Gerlach), so that the 
cells are connected with the fibres only indirectly through the nerve-network. The 
arrangement of the fibres in the anterior horn of the gray matter appears to be 
somewhat different: here the nerve-fibres of the anterior root are directly con- 
tinuous with some of the processes of the ganglion-cells, others of the processes 
communicating with Gerlach's nerve-network. 
The nerve-cells of the gray matter are of two kinds-large branched nerve-vesi- 
cles which are collected into groups, and small round cells which resemble free nuclei 
and are found scattered throughout the whole of the gray matter. 
In the anterior horn there are two or three groups of nerve-vesicles-one at the 660 
THE NERVOUS SYSTEM. 
outer part of the cornu, and one, sometimes two, in the anterior portion (Fig. 436). 
Fig. 437. 
PosP Poots 
PestT ' 
Column 
Fig. 438. 
Gelat ' 
Substance. 
Grey 
Substmce 
Transverse Section through the White Matter of the Spinal Cord 
of a Calf (magnified about 300 diameters-Klein and Noble 
Smith). In the upper part are shown two isolated flattened 
nucleated cells of the neuroglia under a somewhat higher 
power than the rest. In the bulk of the figure the nerve- 
fibres are seen in transverse section. They are of different 
sizes, and possess a laminated medullary sheath surrounding 
the axis-cylinder; which [last] was deeply stained in the prep- 
aration, and is here represented by ablack dot. The nerve-fibres 
are imbedded in the neuroglia. This contains, in a matrix 
which appears sometimes granular, sometimes homogeneous, 
numerous elastic fibrils, seen here in transverse section as mi- 
nute dots, on account of their having a course parallel to the 
long axis of the cord. Amongst the neuroglia are also seen 
two branched connective-tissue cells-neuroglia-cells. 
AnA ' 
Column- 
Longitudinal Section of the White and Gray- 
Substance of the Spinal Cord, through the 
middle of the lumbar enlargement (mag. 
14 diam.-J. L. Clarke del.). 
AjP Hoots 
In the posterior horn, occupying the whole inner half of the cervix, is a group of 
nerve-cells, called the posterior vesicular column of Clarke [Fig- 385, p. 547]. 
At the junction of the anterior and 
posterior cornu, in the outer portion of 
the gray matter, is a third group of cells, 
the tractus intermedio-lateralis. In the 
cervical region of the cord these cells ex- 
tend in amongst the fibres of the white 
matter of the lateral column. [See Fig. 
385, p. 547, for the location of the groups 
of cells in the cord, as well as the arterial 
supply of the cord.] 
Origin of the Spinal Nerves in the 
Cord.-The posterior roots are larger 
than the anterior, but their component 
filaments are finer and more delicate. 
They are attached to the cord at the 
junction of the lateral and posterior col- 
umns, and at once enter the posterior horn 
of gray matter, either directly through the 
substantia gelatinosa, or indirectly by pass- 
ing through the posterior column and en- 
tering the gray substance in front of the 
caput cornu. The former pass upward and 
downward and become continuous with Gerlach's nerve-network, some of the fibres 
extending across the commissure to the opposite side of the cord, others reaching 
Fig. 439. 
From a Transverse Section through the Spinal Cord 
of a Calf (magnified about 180 diameters, showing 
part of the central canal and the tissue immedi- 
ately around it- viz. the central gray nucleus - 
Klein and Noble Smith): The canal is lined with 
epithelium, composed of ciliated more or less con- 
ical cells; in most instances a filamentous process 
passes from the cell into the tissue underneath. 
This tissue contains, in a hyaline matrix, a network 
of fibrils; most of these run horizontally, others 
have a longitudinal course, and appear therefore 
here cut transversely-i. e. as small dots. The nu- 
clei correspond to the cells of the neuroglia, the 
cell-substance not being shown. Both the nuclei 
of the neuroglia-cells and those of the epithelium 
contain three or more large disk-shaped particles. DURA MATER. 
661 
the anterior column on the same side. The latter fibres enter the posterior vesicu- 
lar column, and some, passing through it, run longitudinally in the posterior column 
(Figs. 436, 437). 
The anterior roots are attached exclusively to the anterior column, or rather 
to the anterior part of the antero-lateral columns, for there is no antero-lateral 
fissure dividing the anterior from the lateral column. Within the gray substance 
the fibrils cross each other, and diverge in all directions like the expanded hairs of 
a brush (Figs. 436, 437), some of them running more or less longitudinally upward 
and downward, and others decussating with those of the opposite side through the 
anterior commissure in front of the central canal. 
All the fibres of both roots of the nerves proceed through the white columns into 
the gray substance, with perhaps the exception of some which appear to run longi- 
tudinally in the posterior columns; but whether these latter fibres of the posterior 
roots ultimately enter the gray substance of the cord after a very oblique course, 
or whether they proceed upward to the brain, is uncertain. 
The central canal of the spinal cord (Fig. 439) is lined by a layer of columnar 
ciliated epithelium: external to this is a considerable accumulation of neuroglia, 
forming a cylindrical mass which is called the central gray nucleus of Kblliker. 
THE [ENCEPHALON OR] BRAIN AND ITS MEMBRANES. 
Dissection.-To examine the brain with its membranes the skull-cap must be removed. In 
order to effect this, saw through the external table, the section commencing in front about an 
inch above the margin of the orbit, and extending behind to a level with the occipital protuber- 
ance. Then break the internal table with the chisel and hammer, to avoid injuring the invest- 
ing membranes or brain ; loosen and forcibly detach the skull-cap, when the dura mater will be 
exposed. The adhesion between the bone and the dura mater is very intimate, and much more 
so in the young subject than in the adult. 
The membranes of the brain are-the dura mater, arachnoid membrane, and pia 
mater. 
Dura Mater. 
The Dura Mater is a thick and dense inelastic fibrous membrane which lines the 
interior of the skull. Its outer surface is rough and fibrillated, and adheres closely 
to the inner surface of the bones, forming their internal periosteum, this adhesion 
being more intimate opposite the sutures and at the base of the skull; at the mar- 
gin of the foramen magnum it becomes continuous with the dura mater lining the 
spinal canal. Its inner surface is smooth and lined by a layer of endothelial cells. 
It sends numerous processes inward, into the cavity of the skull, for the support 
and protection of the different parts of the brain, and is prolonged to the outer sur- 
face of the skull through the various foramina which exist at the base, and thus 
becomes continuous with the pericranium; its fibrous layer forms sheaths for the 
nerves which pass through these apertures. At the base of the skull it sends a 
fibrous prolongation into the foramen caecum; it lines the olfactory groove, and 
sends a series of tubular prolongations round the filaments of the olfactory nerves 
as they pass through the cribriform plate and also through the nasal slit; a pro- 
longation is also continued through the sphenoidal fissure into the orbit, and another 
is continued into the same cavity through the optic foramen, forming a sheath for the 
optic nerve, which is continued as far as the eyeball. In the posterior fossa it sends 
a process down the internal auditory meatus, ensheathing the facial and auditory 
nerve; another through the jugular foramen, forming a sheath for the structures 
which pass through this opening; and a third through the anterior condyloid fora- 
men. Around the foramen magnum it is closely adherent to the bone, and is con- 
tinuous with the dura mater lining the spinal canal. In certain situations in the 
skull already mentioned (p. 619) the fibrous layers of this membrane separate to 
form sinuses for the passage of venous blood. Upon the upper surface of the dura 
mater, in the situation of the longitudinal sinus, may be seen numerous small 
whitish bodies, the glandules Pacchioni. 662 
THE NERVOUS SYSTEM. 
Structure.-The dura mater consists of white fibrous and elastic tissues 
arranged in flattened laminae which are divisible into two layers, the fibres of the 
two layers intersecting each other obliquely. A layer of nucleated endothelial 
plates similar to those found on serous membranes lines its inner surface; these 
were formerly regarded as belonging to the arachnoid membrane. 
Its arteries are very numerous, but are chiefly distributed to the bones. Those 
found in the anterior fossa are the anterior meningeal branches of the anterior and 
posterior ethmoidal and internal carotid. In the middle fossa are the middle and 
small meningeal branches of the internal maxillary, and a branch from the ascend- 
ing pharyngeal which enters the skull through the foramen lacerum medium basis 
cranii. In the posterior fossa are the meningeal branch of the occipital, which 
enters the skull through the jugular foramen; the posterior meningeal, from the 
vertebral; and occasionally meningeal branches from the ascending pharyngeal, 
which enter the skull, one at the jugular foramen, the other at the anterior con- 
dyloid foramen. 
The veins which return the blood from the dura mater and partly from the 
bones anastomose with the diploic veins. These vessels terminate in the various 
sinuses, with the exception of two which accompany the middle meningeal artery 
and pass out of the skull at the foramen spinosum to join the internal maxillary 
vein. 
The nerves of the dura mater are-the recurrent branch of the fourth and fila- 
ments from the Gasserian ganglion, from the ophthalmic and hypoglossal nerves, 
and from the sympathetic. 
The so-called glandulae Pacchioni are numerous small whitish granulations, 
usually collected into clusters of variable size, which are found in the following 
situations: 1, upon the outer surface of the dura mater, in the vicinity of the 
superior longitudinal sinus, being received into little depressions on the inner sur- 
face of the calvarium; 2, on the inner surface of the dura mater; 3, in the supe- 
rior longitudinal sinus; 4, on the pia mater near the margin of the hemispheres. 
These bodies are not glandular in structure, but simply enlarged normal villi of 
the arachnoid. In their growth they perforate the dura mater, and are thus found 
on its outer surface, and when of large size they cause absorption of the bone and 
come to be lodged in pits or depressions on the inner table of the skull. The man- 
ner in which they perforate the dura mater is as follows: At an early period of 
their growth they project through minute holes in the inner layer of the dura 
mater, which open into large venous spaces, situated in the tissues of the mem- 
brane, on either side of the longitudinal sinus and communicating with it. In 
their onward growth the villi push the outer layer of the dura mater before them, 
and this forms over them a delicate membranous sheath. In structure they consist 
of trabeculae of connective tissue covered over by a layer of epithelium. The 
spongy tissue of which they are composed is continuous with the trabecular tissue 
of the subarachnoid space. 
These bodies are not found in infancy, and very rarely until the third year. They 
are usually found after the seventh year, and from this period they increase in num- 
ber as age advances. Occasionally they are wanting. 
Processes of the Dura Mater.-The processes of the dura mater sent inward 
into the cavity of the skull are three in number-the falx cerebri, the tentorium 
cerebelli, and the falx cerebelli. 
The falx cerebri, so named from its sickle-like form, is a strong arched process 
of the dura mater which descends vertically in the longitudinal fissure between the 
two hemispheres of the brain. It is narrow in front, where it is attached to the 
crista galli of the ethmoid bone, and broad behind, where it is connected with the 
upper surface of the tentorium. Its upper margin is convex, and attached to the 
inner surface of the skull as far back as the internal occipital protuberance. In this 
situation it is broad, and contains the superior longitudinal sinus. Its lower margin 
is free, concave, and presents a sharp curved edge, which contains the inferior longi- 
tudinal sinus. ARACHNOID MEMBRANE. 
663 
The tentorium cerebelli is an arched lamina of dura mater elevated in the middle 
and inclining downward toward the circumference. It covers the upper surface of 
the cerebellum, and supports the posterior lobes of the brain and prevents them 
pressing upon the cerebellum. It is attached behind, by its convex border, to the 
transverse ridges upon the inner surface of the occipital bone, and there encloses 
the lateral sinuses; in front to the superior margin of the petrous portion of the 
temporal bone, enclosing the superior petrosal sinuses; and at the apex of this bone 
the free or internal border and the attached or external border meet, and, forming 
two processes, cross one another and are continued forward to be attached to the 
anterior and posterior clinoid processes respectively. Along the middle line of its 
upper surface the posterior border of the falx cerebri is attached, the straight sinus 
being placed at their point of junction. Its anterior border is free and concave, 
and presents a large oval opening for the transmission of the crura cerebri. 
The falx cerebelli is a small triangular process of dura mater received into the 
indentation between the two lateral lobes of the cerebellum behind. Its base is 
attached above to the under and back part of the tentorium; its posterior margin, 
to the lower division of the vertical crest on the inner surface of, the occipital bone. 
As it descends it sometimes divides into two smaller folds, which are lost on the sides 
of the foramen magnum. 
The Arachnoid like a spider's web), so named from its extreme 
thinness, is a delicate membrane which envelops the brain, lying between the pia 
mater internally and the dura mater externally; from this latter membrane it is 
separated by a space, the subdural space.1 
It invests the brain loosely, being separated from direct contact with the cerebral 
substance by the pia mater and a quantity of loose areolar tissue, the subarachnoid- 
can. On the upper surface of the cerebrum the arachnoid is thin and transparent, 
and may be easily demonstrated by injecting a stream of air beneath it by means 
of a blowpipe ; it passes over the convolutions without dipping down into the sulci 
between them. At the base of the brain the arachnoid is thicker, and slightly 
opaque toward the central part; it covers the anterior lobes, and is extended across 
between the two middle lobes so as to leave a considerable interval between it and 
the brain, the anterior subarachnoidean space: it is in contact with the pons and 
under surface of the cerebellum; but between the hemispheres of the cerebellum 
and the medulla oblongata another considerable interval is left between it and the 
brain, called the posterior subarachnoidean space. These two spaces communicate 
together across the crura cerebelli. The arachnoid membrane surrounds the nerves 
which arise from the brain, and encloses them in loose sheaths as far as their point 
of exit from the skull. 
The subarachnoid space is the interval between the arachnoid and pia mater: 
this space is narrow on the surface of the hemispheres, but at the base of the brain 
a wide interval is left between the two middle lobes, and behind between the hemi- 
spheres of the cerebellum and the medulla oblongata. This space is the seat of an 
abundant serous secretion, the cerebro-spinal fluid, which fills up the interval between 
the arachnoid and pia mater. The subarachnoid space usually communicates with 
the general ventricular cavity of the brain by means of an opening in the inferior 
boundary of the fourth ventricle. 
The subdural space also contains fluid; this is, however, small in quantity com- 
pared with the cerebro-spinal fluid. 
Structure.-The arachnoid consists of bundles of white fibrous and elastic tissue 
intimately blended together. Its outer surface is covered with a layer of endothe- 
lium. From its inner surface are given off a number of bundles of fine connective 
tissue, which form a sponge-like trabecular network in the subarachnoid space, in 
the interstices of which the cerebro-spinal fluid is contained. Vessels of considerable 
Arachnoid Membrane. 
1 See foot-note, p. 653. 664 
THE NERVOUS SYSTEM. 
size, but few in number, and, according to Bochdalek, a rich plexus of nerves derived 
from the motor division of the inferior maxillary, the facial, and the spinal accessory 
nerves, are found in the arachnoid. 
The cerebro-spinal [or cephalo-rachidian\ fluid fills up the subarachnoid space. 
It is a clear, limpid fluid, having a saltish taste and a slightly alkaline reaction. 
According to Lassaigne, it consists of 98.5 parts of water, the remaining 1.5 per 
cent, being solid matters, animal and saline. It varies in quantity, being most 
abundant in old persons, and is quickly reproduced. Its chief use is probably to 
afford mechanical protection to the nervous centres and to prevent the effects of 
concussions communicated from without. 
The Pia Mater is a vascular membrane, and derives its blood from the internal 
carotid and vertebral arteries. It consists of a minute plexus of blood-vessels held 
together by an extremely fine areolar tissue. It invests the entire surface of the 
brain, dipping down between the convolutions and laminae, and is prolonged into 
the interior, forming the velum interpositum and choroid plexuses of the fourth 
ventricle. Upon the surfaces of the hemispheres, where it covers the gray matter 
of the convolutions, it is very vascular, and gives oft' from its inner surface a mul- 
titude of minute vessels which extend perpendicularly for some distance into the 
cerebral substance. At the base of the brain, in the situation of the anterior and 
posterior perforated spaces, a number of long straight vessels are given off, which 
pass through the white matter to reach the gray substance in the interior. On the 
cerebellum the membrane is more delicate and the vessels from its inner surface are 
shorter. Upon the crura cerebri and pons Varolii its characters are altogether 
changed; it here presents a dense fibrous structure marked only by slight traces 
of vascularity. 
According to Fohmann and Arnold, this membrane contains numerous lymphatic 
vessels. Its nerves are derived from the sympathetic, and also from the third, fifth, 
sixth, facial, glosso-pharyngeal, pneumogastric, and spinal accessory. They accom- 
pany the branches of the arteries. 
Pia Mater. 
The Brain, 
The Brain (encephalon) is that portion of the cerebro-spinal axis which is con- 
tained in the cranial cavity. It is divided into four principal parts-viz. the cere- 
brum, the cerebellum, the pons Varolii, and the medulla oblongata. 
The Cerebrum forms the largest portion of the encephalon, and occupies a con- 
siderable part of the cavity of the cranium, resting in the anterior and middle fossae 
of the base of the skull, and separated posteriorly from the cerebellum by the ten- 
torium cerebelli. About the middle of its under surface is a narrow constricted 
portion, part of which, the crura cerebri, is continued onward into the pons Varolii 
below, and through it to the medulla oblongata and spinal cord, whilst another por- 
tion, the crura cerebelli, passes down into the cerebellum. 
The Cerebellum (little brain or after-brain) is situated in the inferior occipital 
fossae, being separated from the under surface of the posterior lobes of the cerebrum 
by the tentorium cerebelli. It is connected to the rest of the encephalon by means 
of connecting bands called crura: of these, two ascend to the cerebrum, two 
descend to the medulla oblongata, and two blend together in front, forming the 
pons Varolii. 
The Pons Varolii is that portion of the encephalon which rests upon the upper 
part of the basilar process and body of the sphenoid bone. It constitutes the bond 
of union of the various segments above named, receiving above the crura from the 
cerebrum; at the sides, the crura from the cerebellum; and below, the medulla 
oblongata. 
The Medulla Oblongata extends from the lower border of the pons Varolii to MEDULLA OBLONGATA. 
665 
the upper part of the spinal cord. It lies beneath the cerebellum, resting on the 
lower part of the basilar groove of the occipital bone. 
Weight of the Encephalon.-The average weight of the brain in the adult 
male is 49| oz., or a little more than 3 lb. avoirdupois; that of the female, 44 oz.; 
the average difference between the two being from 5 to 6 oz. The prevailing 
weight of the brain in the male ranges between 46 oz. and 53 oz.; and in the 
female, between 41 oz. and 47 oz. In the male the maximum weight out of 278 
cases was 65 oz., and the minimum weight 34 oz. The maximum weight of the 
adult female brain, out of 191 cases, was 56 oz., and the minimum weight 31 oz. 
According to Luschka, the average weight of a man's brain is 1424 grammes 
(about 45 ounces), of a woman's, 1273 grammes (about 41 ounces); and according 
to Krause, 1570 grammes (about 48J oz.) for the male and 1350 (about 43 oz.) for 
the female. It appears that the weight of the brain increases rapidly up to the 
seventh year, more slowly to between sixteen and twenty, and still more slowly to 
between thirty and forty, when it reaches its maximum. Beyond this period, as 
age advances and the mental faculties decline, the brain diminishes slowly in weight, 
about an ounce for each subsequent decennial period. These results apply alike to 
both sexes. 
The size of the brain was formerly said to bear a general relation to the intel- 
lectual capacity of the individual. Cuvier's brain weighed rather more than 64 oz., 
that of the late Dr. Abercrombie 63 oz., and that of Dupuytren 62| oz. On the 
other hand, the brain of an idiot seldom weighs more than 23 oz. But these facts 
are by no means conclusive, and it is well known that these weights have been 
equalled by the brains of persons who never displayed any remarkable intellect. 
Dr. Haldennan of Cincinnati has recorded the case of a mulatto, aged forty-five, 
whose brain weighed oz.; he had been a slave, and was never regarded as par- 
ticularly intelligent; he was illiterate, but is said to have been reserved, medita- 
tive, and economical. Dr. Ensor, district medical officer at Port Elizabeth, reports 
that the brain of Cary, the Irish informer, weighed 61 oz. M. Nikiforoff has pub- 
lished an article on the subject of the weight of brains in the Novosti. According 
to him, the weight of the brain has no influence whatever on the mental faculties. 
It ought to be remembered that the significance of the weight of the brain should 
depend upon the proportion it bears to the dimensions of the whole body and to the 
age of the individual. It is equally important to know what was the cause of death, 
for long disease or old age exhausts the brain. To define the real degree of devel- 
opment of the brain it is therefore necessary to have a knowledge of the condition 
of the whole body, and, as this is usually lacking, the mere record of weight pos- 
sesses little significance. 
The human brain is heavier than that of all the lower animals, excepting 
the elephant and whale. The brain of the former weighs from 8 lb. to 10 lb., 
and that of a whale, in a specimen seventy-five feet long, weighed rather more 
than 5 lb. 
Medulla Oblongata 
The Medulla Oblongata is the upper enlarged part of the spinal cord, and 
extends from the upper border of the atlas to the lower border of the pons Varolii. 
It is directed [from above] obliquely downward and backward; its anterior surface 
rests on the basilar groove of the occipital bone; its posterior surface is received 
into the fossa between the hemispheres of the cerebellum, forming the floor of the 
fourth ventricle. It is pyramidal in form, its broad extremity directed upward, its 
lower end being narrow at its point of connection with the cord. It measures an 
inch and a quarter in length, three-quarters of an inch in breadth at its widest part, 
and half an inch in thickness. Its surface is marked, in the median line in front 
and behind, by an anterior and posterior median fissure, which are continuous with 
those of the spinal cord. The anterior fissure contains a fold of pia mater, and ter- 
minates just below the pons in a cul-de-sac, the foramen ccecum. The posterior is 666 
THE NERVOUS SYSTEM. 
a deep but narrow fissure continued upward to about the middle of the medulla, 
where it expands into the fourth ventricle. These two fissures divide the medulla 
into two symmetrical halves, each lateral half being subdivided by minor grooves 
into foui' columns, which, from before backward, are named the anterior pyramid, 
lateral tract and olivary body, the restiform body, 
the posterior pyramid. 
The anterior pyramids, or corpora pyrami- 
dalia, are two pyramidal bundles of white matter 
placed one on either side of the anterior median 
fissure, and separated from the olivary body, which 
is external to them, by a slight depression. At the 
lower border of the pons they are somewhat con- 
stricted ; they then become enlarged and taper 
slightly as they descend, being continuous below 
with the anterior columns of the cord. On sepa- 
rating the pyramids below it will be observed that 
their innermost fibres form from four to five bundles 
on each side, which decussate with one another 
across the anterior median fissure; this decussa- 
tion, however, is not formed of fibres from the an- 
terior column of the cord, but from the deep por- 
tion of the lateral columns, which pass forward 
to the surface between the diverging anterior col- 
umns. The outermost fibres do not decussate; they 
are derived from the anterior columns of the cord, 
and are continued directly upward through the pons Varolii. 
Lateral Tract and Olivary Body.-The lateral tract is continuous with part 
of the lateral column of the cord. Below it is broad, and includes that part of 
the medulla between the anterior pyramids and restiform body; but above it is 
pushed a little backward and narrowed by the projection 
forward of the olivary body. 
The olivary bodies are two prominent oval masses 
situated behind the anterior pyramids, from which they 
are separated by slight grooves. They equal in breadth 
the anterior pyramids, are a little broader above than be- 
low, and are about half an inch in length, being separated 
above from the pons Varolii by a slight depression. Nu- 
merous white fibres (fibrai arciformes') are seen winding 
round the lower end of each body, sometimes crossing their 
surface, and it is separated above from the lower border 
of the pons by a band of arched fibres. 
The restiform bodies (Fig. 441) are the largest columns 
of the medulla, and continuous below with the posterior col- 
umns of the cord. They are two rounded, cord-like emi- 
nences placed between the lateral tracts in front and the 
posterior pyramids behind, from both of which they are 
separated by slight grooves. As they ascend they diverge 
from each other, assist in forming the lateral boundaries 
of the fourth ventricle, and then enter the corresponding 
hemisphere of the cerebellum, forming its inferior peduncle, 
while other fibres are continued from the restiform bodies 
into the cerebrum. 
The posterior pyramids (funiculi graciles') are two 
narrow white cords placed one on each side of the posterior median fissure, and sepa- 
rated from the restiform bodies by a narrow groove. They consist entirely of white 
fibres, and are continuous with the posterior median columns of the spinal cord. 
These bodies lie at first in close contact. Opposite the apex of the fourth ventricle 
Fig. 440. 
v/Rdtincle 
■ICertltlluTTV 
Medulla Oblongata and Pons Varolii, 
anterior surface. 
Fig. 441. 
Posterior Surface of the Medulla 
Oblongata. MEDULLA OBLONGATA. 
667 
they form an enlargement (processus clavatus), and then diverging form the lateral 
boundaries of the lower part of the fourth ventricle, and, gradually tapering off', 
become lost in the corresponding restiform body. 
The posterior surface of the medulla oblongata forms part of the floor of the 
fourth ventricle. It is of a triangular form, bounded on each side by the diverging 
posterior pyramids, and is that part of the ventricle which from the resemblance to 
the point of a pen is called the calamus scriptorius. The divergence of the posterior 
pyramids and restiform bodies opens to view the gray matter of the medulla, which 
is continuous below with the gray commissure of the cord. In the middle line is 
seen a longitudinal furrow continuous with the posterior median fissure of the cord, 
terminating below, at the point of the ventricle, in a cul-de-sac, the ventricle of 
Arantius, which descends into the medulla to a slight extent. It is the remains of 
a canal which in the foetus extends throughout the entire length of the cord. [This 
statement is erroneous. The canal persists throughout life, and is the " central 
canal" of the cord (Fig. 433, p. 657). The ventricle of Arantius is therefore 
only apparently a cul-de-sac. The central canal, or "ventricle of the cord," is 
continuous with the fourth ventricle, and is the lowest one of the continuous series 
of cavities in the interior of the central nervous system, due to its mode of devel- 
opment.] 
Structure.-The medulla oblongata, like the spinal cord, consists of both gray 
and white matter. But the outer surface of the medulla does not consist so exclus- 
ively of white matter as in the cord, for the gray matter is exposed on its posterior 
surface, forming the floor of the fourth ventricle by the divergence of the restiform 
bodies and posterior pyramids. The white matter is arranged, as has been described, 
into four columns, and through these the fibres of the cord can be traced upward 
into the rest of the encephalon. 
The anterior pyramid is composed of fibres derived from the direct pyramidal 
fasciculus of the anterior column of the cord of its own side, and from the crossed 
pyramidal fasciculus (fasciculus of Tiirck) of the lateral column of the opposite half 
of the cord, and is continued upward into the cerebrum and cerebellum. The fibres 
may be divided into three sets, internal, middle, and external. The internal, the 
chief mass of fibres from the pyramid, enter the pons, and, coursing through the 
superficial layer of the crus, pass upward to the cerebrum. The middle fasciculus 
encloses the olivary body, and, receiving fibres from it, enters the pons as the 
olivary fasciculus or fillet. The external fibres pass beneath the olivary body to 
the restiform body, and spread out into the structure of the cerebellum. The ante- 
rior pyramids contain no gray matter. 
The lateral tract is continuous below with the lateral column of the cord. 
Its fibres pass in three different directions. The most external join the resti- 
form body and pass to the cerebellum. The internal, more numerous, pass for- 
ward, pushing aside the fibres of the anterior column, and form part of the oppo- 
site anterior pyramid under the name of ."crossed pyramidal fasciculus." The 
middle fibres ascend beneath the olivary body to the cerebrum, passing along the 
back of the pons, and formf together with fibres from the restiform body and 
posterior pyramids, the fasciculi teretes in the floor of the fourth ventricle. 4 
Olivary Body.-If a transverse section is made 
through either olivary body, it will be found to 
consist of a small ganglionic mass deeply imbedded 
in the medulla, partly appearing on the surface as 
a smooth, olive-shaped eminence (Fig. 442). It 
consists externally of a white substance, and in- 
ternally of a gray nucleus, the corpus dentatum. 
The gray matter is arranged in the form of a hol- 
low capsule, open at its upper and inner part, and 
presenting a zigzag or dentated outline. A bite 
fibres pass into or from the interior of this body by the aperture in the upper .part 
of the capsule. They join with those fibres of the anterior column which ascend on 
Fig. 442. 
posterior FtssarS'. 
Ftscicuh Teretes 
Restifirm Body 
\Qlivaru Body 
Anterior Fissure/ 
Anterior FpramCd 
Transverse Section of Medulla Oblongata. 668 
THE NERVOUS SYSTEM. 
the outer side and beneath the olivary body to form the olivary fasciculus, which 
ascends to the cerebrum. 
The restiform body is formed chiefly of fibres from the fasciculus cuneatus of the 
posterior column of the cord, which is continued up into the lower part of the 
medulla under the same name. In the medulla between the fasciculus cuneatus and 
the posterior pyramid there exists another tract, called the funiculus of Rolando, 
which is produced by the enlargement and approach to the surface of the caput cornu 
of the gray matter. These two fasciculi, the fasciculus cuneatus and the funiculus 
of Rolando, are joined by some transverse bundles of fibres, the arciform fibres of 
Rolando, which pass from the anterior median fissure across the olivary body, and 
the three form the restiform body. On entering the pons it divides into two fas- 
ciculi above the point of the fourth ventricle. The external fasciculus enters the 
cerebellum; the inner fasciculus joins the posterior pyramid, is continued up along 
the fourth ventricle, and can be traced up to the cerebrum with the fasciculi teretes. 
Fig. 443. 
Po ns Varalli 
Medulla Oblong ata, 
The Columns of the Medulla Oblongata, and their connection with the cerebrum and cerebellum. 
The posterior pyramid is formed by the fasciculus of Goll of the posterior 
column of the cord; it joins the fasciculus teres and is continued with it to the 
cerebrum. 
The course of the fibres of the medulla will be better understood by reference to 
the accompanying plan (Fig. 445, p. 671), copied, by permission of Mr. H. E. Clark, 
from Wilson's Anatomist's Vade-Mecum; [and Fig. 444, from Flechsig]. 
Septum of the Medulla Oblongata.-Above the decussation of the anterior pyra- 
mids numerous white fibres extend from behind forward in the median line, forming 
a septum which subdivides the medulla into two lateral halves. Some of these fibres 
emerge at the anterior median fissure, and form a band which curves round the lower 
border'of the olivary body or passes transversely across it, and round the side of 
the medulla, forming the arciform fibres of Rolando. Others appear in the floor of 
the fourth ventricle issuing from the posterior median fissure, and form the white 
strife in that situation. 
Gray Matter of the Medulla Oblongata.-[For the vascular supply of the me- 
dulla, as well as the location of some of its nuclei, see Fig. 386, p. 548.] The gray 
matter of the medulla oblongata, which contains many multipolar ganglion-cells, is PONS VAROLII. 
669 
partly continuous with the gray matter of the cord and partly arranged in independ- 
ent masses. In the lower part of the medulla the gray matter, which is continuous 
with the cord, is arranged in the shape of two crescentic horns, with their convexi- 
ties toward each other and connected by a central commissure; but in the upper part 
it loses its crescentic arrangement, becomes more abundant, and is disposed with less 
regularity. The posterior horns become enlarged and gradually shifted outward, so 
that they form rounded masses close under the surface of the lateral columns, and 
have received the names of the tubercles of Rolando. The rest of the posterior 
horn surrounds the posterior part of the central canal, but as this expands into the 
fourth ventricle the gray matter is pushed outward into the posterior pyramid and 
the fasciculus cuneatus, which is passing upward to form the restiform body; in 
•each of these funiculi it forms a distinct accumulation of gray matter, constituting 
the nucleus gracilis and the nucleus cuneatus. The anterior horn of gray matter 
is broken up by the passage through it of the crossed pyramidal fibres from the 
lateral column of the cord. By this means the anterior portion of the horn is com- 
pletely isolated from the remainder and constitutes the lateral nucleus of gray mat- 
ter , which is situated near the surface of the lateral column. The rest of the anterior 
horn, being permeated by the decussating fibres, presents a sort of coarse network 
arrangement called the formatio reticularis. The part corresponding to the trans- 
verse gray commissure of the cord is exposed to view by the divergence of the 
posterior white fibres on the surface of the medulla, and forms a continuous mass, 
constituting the floor of the fourth ventricle. The ganglion-cells are here collected 
into groups, forming the so-called nuclei from which many of the cranial nerves 
arise. The lowest of these groups, situated just at the point where the medulla 
commences, and on either side of the central canal, is the nucleus of origin of the 
spinal accessory and hypoglossal nerves; somewhat in front and external to this 
several collections of ganglion-cells are situated, which together constitute the 
nucleus of origin of the pneumogastric nerve, the separate filaments of which the 
nerve consists at its origin arising from the different groups. Higher than this, and 
nearer the anterior part of the medulla, is a third group of cells, which constitutes 
the nucleus of the glosso-pharyngeal. And highest of all, and at some distance from 
the middle line, is the nucleus of the auditory nerve. 
Another independent mass of gray matter is found in the corpus dentatum within 
the olivary body, which is continuous with the posterior part of the formatio reticu- 
laris of the anterior horn. And nearer the septum of the medulla, but continuous 
with the corpus dentatum, is a thin layer or stratum of gray matter called the acces- 
sory corpus dentatum. 
Pons Varolii. 
The Pons Varolii (mesocephale, Chaussier) is the bond of union of the various 
■segments of the encephalon, connecting the cerebrum above, the medulla oblongata 
below, and the cerebellum behind. It is situated above the medulla oblongata, below 
the crura cerebri, and between the hemispheres of the cerebellum. 
Its under surface presents a broad transverse band of white fibres which arches 
like a bridge across the upper part of the medulla, extending between the two hem- 
ispheres of the cerebellum. This surface projects considerably beyond the level of 
these parts, is of quadrangular form, rests upon the sphenoid and basilar groove of 
the occipital bone, and is limited before and behind by very prominent margins. 
It presents along the middle line a longitudinal groove, wider in front than behind, 
which lodges the basilar artery : numerous transverse striae are also observed on 
each side, which indicate the course of its superficial fibres. 
Its upper surface forms part of the floor of the fourth ventricle, and in part is 
in contact with the corpora quadrigemina. 
At each side its fibres become contracted into a thick rounded cord, the crus 
cerebelli, which enters the substance of the cerebellum, constituting its middle 
peduncle. 670 
THE NERVOUS SYSTEM. 
Structure.-The pons Varolii consists of alternate layers of transverse and 
longitudinal fibres intermixed with gray matter (Fig. 443). 
The transverse fibres connect together the two lateral hemispheres of the cer- 
ebellum, and constitute its great transverse commissure. They consist of a super- 
ficial and a deep layer. The superficial layer passes uninterruptedly across the 
[Fig. 444. 
Diagram of the Gray Masses of the Spinal Cord and Brain, showing the course of the conducting paths. 
R, Fissure of Rolando. 
P", P, T, and Pt, Course of the fibres of the pyramidal tract from their origin in the central convolutions to their 
termination in the anterior gray horns (a, a'). 
I, II, III, First, second, and third portions of the lenticular nucleus (NL); NC, Caudate nucleus; Th, Optic 
thalamus. 
D, C, B, A, Points from which fibres issue connecting the cortex of the brain and basal ganglion, and also the 
gray substance of the pons (PO); Bd, Fibres connecting the cerebellum and optic thalamus; and Cap, those 
connecting the cerebellum and the gray substance of the pons. 
aq and pq, Anterior and posterior pair of corpora quadrigemina respectively. 
x, Upper, and x', lower fibres connecting the olivary body and the corpora quadrigemina. 
FR, Formatio reticularis of the medulfa oblongata, formed by fibres from the optic thalamus (Th}, the internal 
division of the inferior peduncle of the cerebellum (icp), from the spinal cord (fr, ar, and ar'), and probably 
also from theclavate nucleus (Nc). 
O, Olivary body; ecp, fibres of the restiform bodies connecting the olivary bodies and cerebellum; other fibres 
connect it with the triangular (Npr) and clavate (Nc) nuclei. 
dp, Decussation of the pyramids. 
pr', Fibres of the posterior roots which pass upward and downward into the gray substance, and pursue only a 
short course. 
a, a', a", a"', anterior roots. 
p, PD pr", G, Fibres of the posterior roots (Flechsig).] 
surface of the pons, forming a uniform layer, which consists of fibres derived from 
the crus cerebelli on each side, meeting in the median line. The deep layer of 
transverse fibres decussates [at a right angle] with the longitudinal fibres continued 
up from the medulla, and contains much gray matter between its fibres. PONS VAROLII. 
671 
OPTIC .THALAMUS 
brain. 
C.STRIATUM 
CRUSTA 
tegmentum 
DIAGRAM OF THE COURSE OF THE FIBRES THROUGH THE MEDULLA TO THE BRAIN. 
CRUS. 
TO CEREBELLUM. 
DECUSSATION OF PYRAMIDS 
ANTERIOR 
Fig. 443. 
MEDULLA, 
I N T. 
CORD. 
LATERAL" 
ANTERIOR. 
i 
ANTERIOR 
LATERAL 
POSTERIOR ■ 
POST. MED. i 672 
THE NERVOUS SYSTEM. 
The longitudinal fibres are continued up through the pons : 1, from the anterior 
pyramid; 2, from the olivary body; 3, from the lateral and posterior columns of 
the cord, receiving special fibres from the gray matter of the pons itself. 
1. The fibres from the anterior pyramid ascend through the pons, imbedded 
between two layers of transverse fibres, being subdivided in their course into 
smaller bundles; at the upper border of the pons they enter the crus cerebri, form- 
ing its fasciculated portion or crusta. 
2. The olivary fasciculus divides in the pons into two bundles, one of which 
ascends to the corpora quadrigemina ; the other is continued to the cerebrum with 
the fibres of-the lateral column. 
3. The fibres from the lateral and posterior columns of the cord, with a bundle 
from the olivary fasciculus and restiform body, are intermixed with much gray 
matter, and appear in the floor of the fourth ventricle as the fasciculi teretes: they 
ascend to the deep or cerebral part of the crus cerebri. 
The gray matter of the pons is irregularly scattered through its substance. No 
gray matter, however, is found on its anterior or superficial surface, which is occu- 
pied exclusively by the superficial transverse white fibres; but the posterior or dor- 
sal surface is chiefly constituted of gray matter, traversed by longitudinal white 
fibres, forming a well-defined formatio reticularis. It is directly continuous with 
the gray matter of the medulla. In this formation are three collections or groups 
of ganglion-cells, forming the nuclei of origin of the facial and trifacial nerves and 
the superior olivary nucleus. 
The superior olivary nucleus is situated in the lower part of the pons, close to 
the medulla, behind the longitudinal* fibres from the anterior pyramid, and is 
enclosed by some transverse fibres called the trapezium. 
Septum.-The pons is suit divided into two lateral halves by a median septum, 
which extends through its posterior half and is continuous with that of the medulla, 
and like it formed by antero-posterior fibres which decussate in the middle line. 
Cerebrum, Upper Surface (Figs. 446, 447). 
The Cerebrum1 in man constitutes the largest portion of the encephalon. Its 
upper surface is of an ovoidal form, broader behind than in front, convex in its 
general outline, and divided into two lateral halves or hemispheres, right and left, 
by the great longitudinal fissure, which extends throughout the entire length of the 
cerebrum in the middle line, reaching down to the base of the brain in front and 
behind, but interrupted in the middle by a broad transverse commissure of white 
matter, the corpus callosum, which connects the two hemispheres together. This 
fissure lodges the falx cerebri, and indicates the original development of the brain 
by two lateral halves. 
Each hemisphere presents an outer surface, which is convex to correspond with 
the vault of the cranium; an inner surface, flattened and in contact with the oppo- 
site hemisphere (the two inner surfaces forming the sides of the longitudinal fissure); 
and an under surface or base, of more irregular form, which rests in front on the 
anterior and middle fossae of the base of the skull and behind upon the tentorium. 
Convolutions.-If the arachnoid is removed with the forceps, the entire sur- 
face of each hemisphere will be seen to present a number of convoluted eminences, 
the convolutions or gyri, separated from each other by depressions (fissures and 
sulci') of various depths. The outer surface of each convolution, as well as the sides 
and bottom of the sulci between them, are composed of gray matter, which is called 
the cortical substance. The interior of each convolution is composed of white mat- 
ter, and white fibres also blend with the gray matter at the sides and bottom of the 
sulci. By this arrangement the convolutions are adapted to increase the amount 
of gray matter without occupying much additional space, while they also afford a 
1 [In studying the brain no one should overlook the splendid Topographical Anatomy of the Brain, 
by Prof. J. C. Dalton, Philadelphia, 1885. In the Brooklyn Annals of Anatomy and Surgery for 1880 
also is an excellent and clear account of much of the anatomy of the cerebrum, bv the same author.] CEREBRUM, UPPER SURFACE. 
673 
greater extent of surface for the termination of the white fibres in the gray matter. 
On closer examination, however, the cortical substance is found subdivided into 
four layers, two of which are composed of gray and two of white matter. The 
most external is an outer white stratum, not equally thick over all parts of the 
brain, being most marked on the convolutions in the longitudinal fissure and on 
the under part of the brain, especially on the middle lobe, near the descending 
horn of the lateral ventricle. Beneath this is a thick reddish-gray lamina, and 
then another thin white stratum; lastly, a thin stratum of gray matter, which lies 
Fig. 446. 
ANTERIOR 
posterior 
1,1, Anterior limit of paracentral lobule. 
2, 2, Upper end of calloso-marginal fissure. 
A, Fissure of Rolando. 
p, Parietal fissure. 
PO, Parieto-oceipital fissure. . 
S, Situation of upper and posterior end of Sylvian fissure. 
X, X, X, Communications between first and second frontal convolutions (Dalton) 
Upper Surface of the Cerebrum. 
in close contact with the white fibres of the hemispheres: consequently, white and 
gray laminae alternate with one another in the convolutions.1 In certain convolu- 
tions, however, the cortical substance consists of no less than six layers, three gray 
and three white, an additional white stratum dividing the most superficial gray one 
into two: this is especially marked in those convolutions which aie situated neai 
the corpus callosum. 
The sulci are generally an inch in depth; they vary in different brains and 
in different parts of the same brain; they are usually deepest on the outer convex 
surface of the hemispheres; the deepest is situated on the inner surface of the hem- 
1 The student should bear in mind that it is extremely doubtful whether these laminae, visible to 
the naked eye, correspond to the layers of which the cortical gray matter is said to be histologically 
composed, and which will presently be described. 674 
THE NERVOUS SYSTEM. 
isphere, on a level with the corpus callosum, and corresponds to the projection in 
the posterior horn of the lateral ventricle, hippocampus minor. 
The number and extent of the convolutions, as well as their depth, appear to 
bear close relation to the intellectual power of the individual, as is shown in their 
increasing complexity of arrangement as we ascend from the lowest Mammalia up 
to man. Thus they are absent in some of the lower orders of Mammalia, and they 
increase in number and extent through the higher orders. In man they present the 
most complex arrangement. Again, in the child at birth, before the intellectual 
faculties are exercised, the convolutions have a very simple arrangement, present- 
ing few undulations, and the sulci between them are less deep than in the adult. 
[Fig. 447. 
F, frontal lobe; P, parietal lobe; 0, occipital lobe ; >51, end of the horizontal branch of the fissura Sylvii; c, cen- 
tral fissure or fissure of Rolando; A, anterior central or ascending frontal convolution; B, posterior central 
or ascending parietal convolution; Flt upper, F2, middle, F3, lower frontal convolution; superior frontal 
sulcus;/2, inferior frontal sulcus;/3, vertical fissure (sulcus prsecentralis); upper or 
lobule; P2, lower parietal lobule, constituted by P2, gyrus supramarginalis, P2, gyrus anguians; ip, inter- 
parietal sulcus; cm, calloso-marginal sulcus; po, parieto-occipital fissure; upper temporal fissure; Oj, first 
occipital convolution; 02, second occipital convolution; o, sulcus occipitalis transversus (Ecker).] 
View of the Brain from Above. 
In old age, when the mental faculties have diminished in activity, the convolutions 
become much less prominently marked. 
The convolutions on the outer convex surface of the hemisphere, the general 
direction of which is more or less oblique, are the largest and most complicated 
convolutions of the brain, frequently becoming branched like the letter Y in their 
course upward and backward toward the longitudinal fissure: these convolutions 
attain their greatest development in man, and are especially characteristic of the 
human brain. They are seldom [exactly] symmetrical on the two sides. 
Fissures.-There are five principal fissures in the brain. Many of the larger 
sulci are, however, called fissures also, but these five are the chief landmarks: 1, 
The great longitudinal fissure, separating the two hemispheres; 2, the great trans- CEREBRUM, UPPER SURFACE. 
675 
verse fissure of Bichat, between the cerebrum and cerebellum, which admits the 
pia mater into the interior of the brain under the hinder end of the corpus callosum 
as the velum interpositum (see p. 696 and Fig. 475, 20, p. 701); 3, the fissure of 
Sylvius ; 4, the fissure of Rolando (c, Figs. 447 and 448); 5, the parieto-occipital 
fissure {po). Of these fissures, the first two separate the great divisions of the 
brain, and the last three separate the lobes of the brain from each other. All 
other fissures are intralobular.1 (For the topographical relations of the cerebral 
surface see p. 681.) 
The fissure of Sylvius [$, S', S"~\ begins at the base of the brain at the anterior 
perforated space, and, passing outward to the external surface of the hemisphere, 
[Fig. 448. 
Outer Surface of the Left Hemisphere. 
F, Frontal lobe; P, parietal lobe; O, occipital lobe; T, temporo-sphenoidal lobe; S, fissure of Sylvius, S', hori- 
zontal, S", ascending ramus of the same: c, sulcus centralis or fissure of Rolando; A, anterior central or 
ascending frontal convolution; B, posterior central or ascending parietal convolution; Fv superior, F„, mid- 
dle, and F3, inferior frontal convolutions; superior, and/2, inferior frontal sulcus; f3, sulcus prsecentralis; 
Pj, superior parietal or postero-parietal lobule; P2, inferior parietal lobule, viz.: P„, gyrus supra-margin- 
alis; P2', gyrus angularis; ip, sulcus intra-parietalis; cm, termination of the calloso-marginal fissure; 
On first, O2, second, 03, third occipital convolutions; po, parieto-occipital fissure; o„ sulcus occipitalis 
trahsversus' o2, sulcus occipitalis longitudinalis inferior; T,, first, T2, second, T3, third temporo-sphe- 
noidal convolutions; G, first, t2, second temporo-sphenoidal fissures (Ecker).] 
divides into two branches: one, passing upward toward the longitudinal fissure, may 
be termed the ascending limb ; the other, the longer one, running nearly horizon- 
tally backward, may be called the horizontal limb.[2] 
The Fissure of Rolando [c] is situated about the middle of the outer surface of 
[' The nomenclature of the fissures and convolutions is by no means yet fixed in detail. The 
student must remember, therefore, that other names may be found in other text-books, and he must 
be careful not to become confused by them.] 
[2 Turner makes the anterior limb of this important fissure continuous with the precentral sulcus, 
and the English editor of Gray has followed this. As nearly all anatomists believe them to be sep- 
arate I have changed the text accordingly. In the figures in the English edition not only is the 
above represented, but the posterior limb of the Sylvian fissure and the intraparietal and the parieto- 
occipital fissures are, all there represented as one continuous fissure, and both the frontal sulci join 
the precentral sulcus. I have substituted the more accurate plates of Ecker. In the text on the 
brain while adhering as nearly as possible to the English edition, I have been compelled to make 
many changes that could not well be indicated by brackets. I have therefore omitted them entirely, 
except in references and to the section on Cerebral Localization and Topography, of which I have 
added the whole.] 676 
THE NERVOUS SYSTEM. 
the hemisphere. It commences at or near the great longitudinal fissure, half an inch 
behind the mid-point between the glabella and the external occipital protuberance, 
and runs downward and forward to terminate a little above the horizontal limb 
of the fissure of Sylvius. The upper two-thirds of its course lies at an angle of 
67° with the great longitudinal fissure. It then becomes more vertical, forming a 
knee-like angle. In front and behind it are two very important convolutions, the 
ascending frontal and ascending parietal convolutions, united above in the paracen- 
tral lobule, and below in the operculum, which overhangs the island of Red. 
The Parieto-occipital Fissure [po~\ is only seen to a slight extent on the outer 
surface of the hemisphere, and is not so distinctly marked as the others. The portion 
on the outer surface of the hemisphere is sometimes called the external parieto-occip- 
ital fissure, to distinguish it from the continuation of the sulcus on the internal surface 
of the hemisphere, which would then be termed the internal parieto-occipital fissure. 
It commences about midway between the posterior extremity of the brain and the 
fissure of Rolando, and runs downward and forward for a variable distance, becom- 
ing indistinct below. 
Lobes.-These three fissures divide the external surface of the hemisphere into 
five lobes-the frontal, the parietal, the occipital, the temporo-sphenoidal, and the 
central or island of Reil [Figs. 447 to 450]. 
The Frontal Lobe is that portion of the brain which is situated in front of the 
fissure of Rolando and above the fissure of Sylvius. Its under surface rests on the 
orbital plate of the frontal bone, and is termed the orbital lobe. 
The precentral or vertical fissure [/3] runs upward through this lobe, dividing 
off a convolution which lies between it and the fissure of Rolando, and Which is 
called the ascending frontal convolution [a]. The front portion of this lobe, on 
the outer surface, is divided into three principal convolutions by two antero-poste- 
rior sulci called the superior and inferior frontal sulci The inferior sulcus 
(/2) generally is united at a right angle with the precentral sulcus (/3). The three 
convolutions are named respectively the superior, middle, and inferior, or first, 
second, and third frontal convolutions [fp F2, f3]. The third is often called Broca's 
convolution. 
The under surface of the frontal lobe, which rests on the orbital plate of the 
frontal bone, is named the orbital lobe (Fig. 449.) It presents a well-marked 
groove or sulcus for the olfactory nerve which often covers most of the sulcus. 
The convolution internal to this sulcus [fJ is the inferior part of the first frontal 
convolution. External to the sulcus this surface of the frontal lobe shows the 
lower ends of the second and third frontal convolutions [f2, f3], sometimes called 
here respectively the internal and external orbital convolutions. The second, owing 
to the short olfactory sulcus, is usually partly blended with the first. 
The Parietal Lobe is bounded in front by the fissure of Rolando, behind by the 
parieto-occipital fissure, and below by the horizontal limb of the fissure of Sylvius, 
which separates it from the temporo-sphenoidal lobe. It presents four well-marked 
convolutions, more or less separated from each other by secondary fissures. Of these 
fissures, one, the intraparietal [ip~\ commences above the horizontal limb of the 
fissure of Sylvius, opposite the knee-like bend in the fissure of Rolando, and runs 
at first upward, parallel to and behind the fissure of Rolando, separating a convo- 
lution, the ascending parietal [b], which thus lies between the fissure of Rolando 
and the intraparietal fissure, and is parallel with the ascending frontal convolution. 
The intraparietal fissure then turns backward, runs parallel with the great longitu- 
dinal fissure, and separates a convolution, the superior parietal [pJ (posterior parie- 
tal lobule), which lies along the margin of the longitudinal fissure. This is contin- 
uous in front with the ascending parietal convolution, and behind is limited by the 
parieto-occipital fissure. The remaining part of the parietal lobe-namely, that 
part between the intraparietal fissure above and in front and the horizontal limb 
of the fissure of Sylvius and the hinder part of the first temporal fissure below-is 
divided into two convolutions by a short vertical fissure: the anterior of these is the 
supramarginal [p2] convolution, and the posterior the angular convolution [p/] ; CEREBRUM, UPPER S UREA CE. 
677 
this latter convolution is joined with the temporo-sphenoidal and occipital lobes by 
small connecting convolutions. The upper ends of the ascending frontal and ascend- 
ing parietal convolutions are known as the paracentral lobule (Fig. 450, Pc). 
The Occipital Lobe is situated at the posterior extremity of the brain, and is 
separated above from the parietal lobe by the parieto-occipital fissure ; below 
and in front it is united with the temporo-sphenoidal and parietal lobes by small 
connecting convolutions. It is imperfectly divided by two small transverse fissures 
into three convolutions, named respectively the first, second, and third occip>- 
ital convolutions [Ox, O2, O3J. 
The Temporo-sphenoidal Lobe [t] is that portion of the hemisphere which is 
lodged in the middle fossa of the base of the skull. In front and above it is lim- 
[Fig. 449. 
View of the Brain from below. 
F„ First frontal convolution or gyrus rectus; F2, middle or second frontal; P3, inferior or third frontal con- 
sulcus olfactorius; /5, sulcus orbitalis; T2, second or middle temporo-sphenoidal convolution; 
T3, third or inferior temporo-sphenoidal convolution; Tit gyrus oecipito-temporalis lateralis (lobulus fusi- 
formis); 7'5, gyrus oecipito-temporalis medialis (lobulus lingualis); t4, sulcus oecipito-temporalis inferior; 
t3, sulcus temporo-sphenoidaiis inferior, or third temporal fissure; t2, sulcus temporo-sphenoidalis medialis, 
or second temporal fissure; po, parieto-occipital fissure; oc, calcarine fissure; II, gyrus hippocampi; U, gyrus 
uncinarus; Ch, optic chiasma; cc, corpora albicantia; KK, crura cerebri; C, corpus callosum (Ecker).] 
ited by the fissure of Sylvius ; behind it is connected with the parietal and occipital 
lobes. It is divided into three convolutions by two antero-posterior fissures, the 
first and second temporo-sphenoidal fissures (tv t2): of these, the upper one runs 
parallel to the horizontal limb of the fissure of Sylvius, and is hence sometimes 
named the parallel fissure. The three convolutions formed by these two fissures 
are named respectively the first, second, and third temporo-sphenoidal convolutions 
in their numerical order from above downward [t15 t2, t3J. 
The Central Lobe or Island of Reil [or Insula] is best seen in section in 
Fig. 469, p. 693, and Fig. 470, p. 694. It is situated in the fissure of Sylvius at 
the base of the brain, and is hidden under the overhanging and fused lower ends of 678 
THE NERVOUS SYSTEM. 
the ascending frontal and ascending parietal convolutions known as the operculum, 
being connected in front with the posterior extremity of the orbital lobe, and sep- 
arated externally by a deep sulcus from the inferior frontal convolution and from 
the lower ends of the ascending frontal and parietal convolutions. It is a triangu- 
lar-shaped prominent cluster of about six convolutions, the gyri operti, so called 
from being covered in by the sides of the fissure. By the removal of these convo- 
lutions the extraventricular part of the corpus striatum would be reached. 
On the inner or median surface of the hemispheres the arrangement of the con- 
volutions is less complex ; they are generally well defined, and, some of them being 
of great length, there is not the same subdivision into smaller lobes as on the exter- 
nal surface (Fig- 450). The fissures on the internal surface are five in number, and 
are named the calloso-marginal, the parieto-occipital, the calcarine, the collateral, 
and the dentate. 
[Fig. 450. 
Inner Surface of Right Hemisphere. 
(70, corpus callosum, longitudinally divided; Gf, gyrus fornicatus; H, gyrus hippocampi; h, sulcus hippocampi, 
or dentate fissure; U, uncinate gyrus; cm, sulcus calloso-marginalis; F1( median aspect of the first frontal 
convolution; c, terminal portion of the sulcus centralis, or fissure of Rolando; A, ascending frontal; 
B, ascending parietal convolution; Pi", precuneus; oz, cuneus; Po, parieto-occipital fissure; o, suicus occip- 
italis transversus; oc, calcarine fissure; oc', superior, oc", inferior ramus of the same; D, gyrus descendens; 
T4, gyrus occipito-temporalis lateralis (lobulis fusiformis); T5, gyrus occipito-temporalis medialis (lobulus 
lingualis); cf, collateral or occipito-temporal fissure (Ecker).] 
The calloso-marginal fissure [cm] is seen in front, commencing below the 
anterior extremity of the corpus callosum; it at first runs forward and upward par- 
allel with the rostrum of the corpus callosum, and, winding round the genu of that 
body, it continues from before backward between the upper margin of the hemi- 
sphere and the corpus callosum to about midway between the anterior and posterior 
extremities of the brain, where it turns upward to reach the upper margin of the 
inner surface of the hemisphere and joins the superior extremity of the fissure of 
Rolando or terminates in its immediate vicinity, generally behind it. It separates 
the marginal or first frontal convolution [f] from the gyrus fornicatus [g/]. 
The parieto-occipital fissure [joo] (internal parieto-occipital) is the continuation 
of the short fissure of the same name seen on the outer surface of the hemisphere. 
It extends in a curved direction downward and forward to join the calcarine fissure. 
It separates the precuneus or quadrate lobe from the cuneate lobe [cuneus, oz]. 
The calcarine fissure [oc] commences usually by two branches [oc', oc"] at the 
back of the hemisphere, runs nearly horizontally forward, and is joined by the 
parieto-occipital fissure, and continues as far as the posterior inferior extremity 
of the gyrus fornicatus. It separates the cuneate lobe [oz] from the lobulus lin- 
gualis [t5]. CEREBRUM, UPPER SURFACE. 
679 
The collateral or occipito-temporal fissure [c/] is situated below the preced- 
ing, being separated from it by the lingual lobule. It runs forward from the pos- 
terior extremity of the brain nearly as far as the commencement of the fissure of 
Sylvius. It lies below the posterior and middle horn of the lateral ventricle, and 
causes the prominence in the interior of the lateral ventricle known as the eminen- 
tia collateralis. 
The dentate fissure or sulcus hippocampi (7i) commences immediately below 
the posterior extremity of the corpus callosum, and runs forward to terminate at the 
recurved part or hook of the uncinate gyrus [u]. It corresponds with the promi- 
nence of the hippocampus major in the descending horn of the lateral ventricle. 
The lobes or convolutions seen on the internal surface of the hemisphere are 
six in number, and are named gyrus fornicatus, marginal, quadrate, cuneate, unci- 
nate, and temporo-sphenoidal. 
The gyrus fornicatus [g/, g/J, or convolution of the corpus callosum, begins just 
in front of the anterior perforated space at the base of the brain; it ascends in front 
of the genu of the corpus callosum and runs backward along the upper surface of 
this body to its posterior extremity, where it passes downward and forward under 
the name of the gyrus hippocampi (h) to terminate as the uncinate gyrus (u) nearly 
opposite where it began. It is bounded above by the calloso-marginal fissure [cm], 
which separates it from the marginal or first frontal convolution [fJ. 
The marginal or first frontal convolution [fJ is situated above the preceding, 
and has received its name from its position along the edge of the longitudinal fissure. 
[Fig. 451. 
Head of a Cadaver from which the scalp has been removed opposite the so-called motor-region of the brain: 
S edge of cut scalp; P, pericranium ; C, coronal suture; S. T. R., ridge of temporal fascia, or superior tem- 
poral ridge (superior stephanion); I. T. R., ridge of temporal muscle, or inferior temporal ridge (inferior 
stephanion) • S Q squamo-parietal suture; T. M., temporal muscle; T. F., temporal fascia (Horsley).] 
It is the inner aspect of the first frontal convolution. It commences in front at the 
anterior perforated space, runs along the margin of the longitudinal fissure on the 
under surface of the orbital lobe, being bounded externally by the sulcus for the 
olfactory nerve: it then turns upward to the upper surface of the hemisphere, and 680 
THE NERVOUS SYSTEM. 
runs backward, forming the marginal convolution on the inner surface to the point 
where the calloso-marginal fissure turns upward to reach the superior border of the 
hemisphere. Its posterior portion, in front of the precuneus or quadrate lobe, par- 
tially cut off by a fairly constant furrow at right angles to the corpus callosum, is 
known as the paracentral lobule (pc). It is the fused upper ends of the ascend- 
ing frontal (a) and ascending parietal (b) convolutions. 
The quadrate lobule or precuneus (pf,) lies between the calloso-marginal 
fissure [m] in front and the parieto-occipital [po] behind. Below it joins the 
gyrus fornicatus. 
The cuneus or occipital lobule [cuneus, a wedge (02)] is triangular in shape, 
being situated between the parieto-occipital [joo] and calcarine fissure [oc], which, 
as above mentioned, meet behind the posterior extremity of the gyrus fornicatus. 
[Fig. 452. 
View of the same Head as Fig. 451, the base being removed by a vertical saw-cut through the inferior stepha- 
nion, by another along the squamo-parietal suture, by one parallel to the fissure of Rolando and just in front 
of the parietal eminence, and by one along the outer border of the sagittal suture: M, margin of the hemi- 
sphere ; S. F. S., superior frontal sulcus: S. F. G., superior frontal gyrus; M. F. G., middle frontal gyrus; P. C. S., 
precentral or vertical sulcus; A. F., ascending frontal gyrus; A. P., ascending parietal gyrus; I. P., intrapari- 
etal sulcus; R, fissure of Rolando; S, fissure of Sylvius; T. M., temporal muscle; T. F., temporal fascia; S. 
T. R., superior temporal ridge (superior stephanion); I. T. R., inferior temporal ridge (inferior stephanion); 
U, subordinate sulcus in ascending frontal gyrus which unites the phonatory centre (Horsley).] 
The uncinate gyrus [u] is the anterior inferior termination of the gyrus for- 
nicatus (g/) through the gyrus hippocampi (h), and extends to the fissure of Syl- 
vius, being bounded above by the dentate fissure [A], and separated below from the 
temporo-sphenoidal lobe by the collateral fissure [c/]. From the anterior extrem- 
ity a narrow portion is recurved or bent backward in the form of a hook, which is 
sometimes called the crochet or uncus. 
The Temporo-sphenoidal Lobe.-The temporo-sphenoidal lobe has on its 
outer surface the three convolutions already described. On its under and inner 
surface are two more, divided from each other by the collateral or occipito-temporal 
sulcus (c/). They are the lateral occipito-temporal convolution or fusiform lobule 
(t4) and the median occipito-temporal convolution or lingual lobule (t5). CEREBRUM, UPPER SURFACE. 
681 
Besides the great primary convolutions above named and described, and which 
can be recognized in almost any well-developed brain, there are a great number of 
secondary convolutions which pass from one to another of the primary, and often 
render the arrangement of the latter somewhat obscure; of these, the connections 
of the occipital lobe above mentioned, and which are named annectant convolutions, 
may be taken as examples. 
[Cerebral Localization and Topography.-Within the last few years, as 
a result chiefly of experiment on the lower animals, the localization of various 
functions, especially those of motion, in different parts of the brain, has made great 
progress and become fairly definite. While the localities in which they are situated 
are not separated by hard and fast lines, they do occupy absolutely constant focal 
positions. In Figs. 453 and 454, from Ferrier, these localities, so far as ascertained 
at present, are indicated. Compare them with Figs. 455 to 463, from Horsley. 
Approximately, as based on experiments on monkeys, and to some extent on 
observations on man, until further clinical and pathological demonstrations in man 
remove the probably slight errors, they must serve as working diagrams. 
(1) on the postero-parietal lobule (precuneus)-the centres for movements of the 
opposite leg and foot in locomotion. 
(2) (3), (4), at the upper end of the fissure of Rolando and hinder part of the 
first frontal convolution-the centres for various complex movements of the arms 
and legs, as in climbing, swimming, etc. In this area Horsley states that the arm 
and leg of the same side are involved together. 
(5) at the posterior part of the superior frontal convolution-extension forward 
of the arm and hand, as in putting forth the hand to touch something in front. 
(6) on the ascending frontal convolution just behind the upper and hinder end 
of the middle frontal convolution-movements of the hand and forearm, in which 
the Biceps is particularly engaged-viz. supination of the hand and flexion of the 
forearm. 
(7) and (8), respectively for the elevators and depressors of the angle of the 
mouth. 
(9) and (10), as one, mark the centre for movements of the lips and tongue, as in 
speech. This especially occupies the posterior portion of the inferior frontal (gen- 
erally known as Broca's) convolution. Disease of this region on the left side pro- 
duces aphasia. 
(11) the centre for the Platysma, retraction of the angle of the mouth. 
(12) a centre for lateral movements of the head and eyes, with elevation of the 
eyelids and dilatation of the pupils. 
(13) and (13'), on the supramarginal lobule and angular gyrus, including also 
the occipital lobe, indicate the centre for vision. 
(14) on the superior temporo-sphenoidal convolution, indicate the c'entre for 
hearing. 
(«), (6), (<?), (<Z), on the ascending parietal convolution, indicate the centres for 
movements of the fingers and wrist. 
The centre for smell is situated in the hook of the hippocampal region (Fig. 
450, u). 
In close proximity, but not exactly defined as to limits, is the centre for taste. 
The centre for touch is situated in the hippocampal region (Fig. 450, h) and 
gyrus fornicatus (g/). 
Figs. 455 to 463, from Horsley, indicate similarly the localization of functions 
in the brain, and the student is referred to his paper1 for a fuller description of 
the areas. 
The relation that these localities of definite function in the brain bear to the 
exterior of the skull itself is of the greatest importance, for if accurately ascer- 
tained we can by means of it determine from the outside just where the fissures, 
sulci, and convolutions lie, and therefore where the above areas for certain func- 
tions are situated. Cerebral topography and localization have been utilized 
1 Amer. Joum. Med. Sei., April, 1887. 682 
THE NERVOUS SYSTEM. 
[Fig. 453. 
Side View of the Brain of Man (Ferrier).] 
[Fig. 454. 
Top View of the Brain of Man (Ferrier).J CER EB R UM, UPPER 8 UR FA CE. 
683 
[Fig. 455. 
[Fig. 456. 
Representation of the Upper Face and Angle of the 
Mouth (Horsley).] 
Representation of the Vocal Chords (adduction) 
(Horsley).] 
[Fig. 457. 
[Fig. 458. 
Representation of the Lower Face and Floor of the 
Mouth (Horsley).] 
Representation of the Shoulder (Horsley).] 
[Fig. 459. 
[Fig. 460. 
Representation of the Elbow and Wrist (Horsley).] 
Representation of the Thumb (Horsley).] 
[Fig. 461. 
[Fig. 462. 
Reproduction of the Combined synchronous Action 
of both Limbs (Horsley).] 
Representation of the Lower Limb: h, focus of Rep- 
resentation of the Hallux (Beevor and Horsley).] 684 
THE NERVOUS SYSTEM. 
[Fig. 463. 
Representation of the Head and Neck, together with Conjugate Deviation of the Eyes (Horsley).] 
recently in the most brilliant operations for the removal of tumors from the cere- 
brum by Godlee,1 Horsley,2 and Weir,3 and others, and from the cerebellum by 
Horsley and May,4 and for the relief of abscess of the brain, etc. The new field 
thus opened gives promise in the near future of the most extraordinary results. 
The following brief account of the topographical relations of the brain (espe- 
cially of the motor region) to the exterior of the skull is appended as the most 
serviceable statement that can at present be made.5 
In determining the functional areas it is more important to be accurate ver- 
tically than horizontally, as the variation of function from above downward is 
greater than from before backward. In these areas "minimal stimulation"-that 
is, just sufficient electrical stimulation to produce any movement-is followed by 
movement of a certain segment of the body rather than of single muscles; and 
if the degree of stimulation be increased, neighboring centres, and therefore other 
segments of the body, are involved (z. e. primary and secondary movements). 
Landmarks on the Skull.-The points to be determined on the skull are 
as follows (Fig. 464): The frontal and parietal eminences can be easily defined by 
the eye and touch. The nasion, N (Broca), is the root of the nose. The ophryon 
(g) is the point where the middle line is crossed by a horizontal line at the level of 
the upper border of the eyebrows. It corresponds in general to the glabella or the 
elevation between the eyebrows. The inion (i) is the base of the external occipital 
protuberance. The stephanion (s) is the point where the upper temporal ridge- 
that is, the one for the temporal fascia-crosses the coronal sutures. This may be 
better called the upper stephanion, the lower stephanion (s') being the intersection 
of the coronal suture and the ridge for the temporal muscle. The pterion (p) is the 
(usually) H-shaped junction of the parietal, great wing of the sphenoid, frontal, and 
temporal bones. The horizontal bar of the H, the spheno-parietal suture, slopes and 
lies halfway between the stephanion and the upper border of the zygoma, an inch and 
a half behind the external angular process. 
The temporal ridges are two in number-the upper for the temporal fascia and 
the lower for the temporal muscle. The upper is the better marked, and can be 
easily followed by the fingei' from the external angular process backward. The 
lower one is best made out by closing and relaxing the jaw, when the upper edge 
of the bellying temporal muscle can be felt by the finger.6 It also begins at the 
external angular process, but runs at a lower level than the fascial ridge, and at the 
middle is about two-fifths of an inch below it. 
The sutures next must be fixed. The lambda (l) or the point of union of the 
1 Lancet, Dec. 20, 1884. ' 2 Brit. Med. Journ.. Oct. 10, 1881, and April 23, 1887. 
3 Medical Neivs, April 16, 1887. 4 Horsley, I. c.; May, Lancet, April 16, 1887. 
[5 In this description I owe much to Mr. Horsley's article in the Amer. Journ. Med. Sci. for April, 
1887. The student desirous of fuller information is referred to this paper; to Ferrier's Functions of 
the Brain; Reid, Lancet, 1884; Turner, Journ. Anat. and Phys., 1873 and 1874, and other works.] 
[6 Horsley, as I think, incorrectly states that the lower (muscular) ridge only has been heretofore 
described. A reference to the text of earlier editions of Gray alone will show that the upper (fascial) 
ridge has been the one described. Broca and others also distinctly note both ridges.] CEREBRUM, UPPER SURFACE. 
685 
sagittal and lambdoidal sutures, the posterior fontanelle, can be easily felt. Brom 
this the lambdoidal suture runs outward and downward on both sides, and can be 
determined with fair accuracy by pushing the scalp backward and forward, when 
its irregularities can be felt. From the lambda the sagittal suture runs in the 
median line forward till it meets the coronal suture at the bregma (b). This point 
can best be fixed by drawing a vertical line from ear to ear over the top of the 
head. Measurement of 185 skulls has given me, as a mean result, that the bregma 
lies 0.375 of an inch in front of the bi-auricular line. The greatest distance was 1.2 
[Fig. 464. 
AT, Nasion (junction of the nasal and frontal). 
G, Ophryon (on a level with the superior border of 
the eyebrows, and corresponding nearly to the 
glabella, the smooth swelling between the eye- 
brows). 
B, Bregma (junction of the sagittal and coronal 
sutures). 
Ob, Obelion (the sagittal suture between the parietal 
foramina). 
L, Lambda (junction of sagittal and lambdoidal su- 
tures). 
I, Inion (external occipital protuberance). 
Basion, middle of anterior wall of foramen magnum. 
Skull showing the Points named by Broca. 
As, Asterion (junction of the occipital, parietal, and 
temporal bones). 
g, Gonion (angle of the lower jaw). 
S', Stephanion (or, better, the superior stephanion, 
intersection of ridge for temporal fascia and 
coronal suture). 
S', Inferior stephanion (intersection of ridge for tem- 
poral muscle and coronal suture). 
P, Pterion (point of junction of great wing of sphe- 
noid and the frontal, parietal, and squamous 
bones. This maybe H-shaped or K-shaped, or 
in which the frontal or temporal 
just touch.] 
inches. In 16 of these skulls the bregma corresponded to the line exactly; in 
only 7 did it lie behind it, the maximum being 0.9 inch. 
Starting from the bregma, by shoving the scalp backward and forward the fin- 
gers can perceive (with some difficulty, however, in certain cases, especially in 
the aged) the irregularities of the coronal suture, but toward the stephanion they 
become more marked, and can be pretty well appreciated. In case of difficulty it 
will assist in finding the suture if the generally well-marked groove on the parietal 
bone behind it, and slighter groove in the frontal bone in front of it, be recognized. 
The suture lies in the ridge between the two grooves. This suture and the two tem- 
poral ridges being determined, the upper and lower stephanions are fixed. 
The arching squamo-parietal suture begins at the pterion. Its highest point is 
at the junction of the upper and middle thirds of a vertical line drawn from the 
upper border of the zygoma to the ridge of the temporal muscle, in front of the 
temporo-maxillary articulation. 
Relation of the Fissures and Convolutions to the Landmarks on the 
Skull.-Fissures and Sulci.-The most important of the fissures to be fixed is the 
fissure of Rolando. Its upper end is (1) about 1| to 2 inches behind the bregma 
(Broca, Turner, and others); or (2), measuring from the glabella backward, 55.7 per 
cent, of the distance between the anterior and posterior limits of the cerebrum- 686 
THE NERVOUS SYSTEM. 
i. e. from glabella to the inion (Hare); or (3) half an inch behind the mid-point of 
the line drawn from the glabella to the inion (Thane). This point being fixed, if a 
line be drawn downward and forward at an angle of 67°, it will give quite accurate- 
ly the upper two-thirds of the fissure of Rolando. The lower third becomes somewhat 
more vertical, forming a knee-like bend. To fix this important fissure, Horsley 
fastens to the middle of a 10-inch strip of metal or of stout paper a second at an 
angle of 67°. Mark a scale of, say, quarter inches both forward and backward on 
each arm of the long median strip, the zero-point of which between the anterior and 
posterior scales, as suggested by Dr. Morris J. Lewis of Philada., shall be half an 
inch in front of the second arm. Placing this long strip in the middle line of the 
head, so that the reading of the scale at the glabella and inion shall be identical, the 
lateral strip will mark the upper two-thirds of the fissure of Rolando. The head 
should be shaved. 
The fissure of Sylvius begins at the pterion (1| inches behind the external angu- 
lar process-Hare). The short anterior branch runs upward and forward, continu- 
ing the line of the squamo-sphenoidal 
suture, but one or two millimeters in 
front of it. The long posterior limb 
passes upward and backward half a mil- 
limeter above the squamo-parietal suture, 
as far as its highest point, and from there 
curves slightly upward toward the centre 
of the parietal eminence, which it nearly 
reaches. The anterior limb of this fis- 
sure runs just in front of the lower end 
of the coronal suture, and limits the 
motor area of the brain anteriorly, while 
its posterior limb limits the same area 
postero-inferiorly. 
The precentral sulcus is of great im- 
portance also, as it divides two convolu- 
tions of very different functions, and on 
each side of it has convolutions of great 
motor importance. It runs parallel to 
and just behind the coronal suture, and is almost vertical to a tangent at the 
bregma; hence its other name, the vertical sulcus. Its upper end reaches to the 
level of the middle of the fissure of Rolando. From it, about on the level of the 
superior temporal ridge (superior stephanion), the inferior frontal sulcus runs for- 
ward. Above the origin of this sulcus the precentral sulcus continues halfway 
across the root of the middle frontal convolution. Its lower end is separated from 
the fissure of Sylvius by a horseshoe-shaped convolution of great importance (the 
operculum), and nearly always one centimeter wide. 
The superior frontal sulcus starts from the ascending frontal convolution midway 
between the fissure of Rolando and the line of the precentral sulcus. Its posterior 
end, therefore, lies behind the precentral sulcus. The superior and inferior frontal 
sulci run forward and slightly downward, practically parallel with the great longi- 
tudinal fissure. 
The intraparietal sulcus lies behind the fissure of Rolando and bounds the motor 
area posteriorly. Its begins opposite the knee-like bend at the junction of the mid- 
dle and lower thirds of the fissure of Rolando. As it goes upward it lies about mid- 
way between the Rolandic fissure and the parietal eminence. It then separates 
farther from the fissure of Rolando, and so widens the ascending parietal convolu- 
tion that its upper end is known as a lobule-the superior parietal lobule. In the 
middle of its course it runs about parallel to the great longitudinal fissure and mid- 
way between it and the parietal eminence. Farther on it passes by the external 
end of the parieto-occipital fissure, and goes downward and backward into the 
occipital lobe. 
[Fig. 465. 
P.O., parieto-occipital fissure (external); I. P., intra- 
parietal sulcus; R., fissure of Rolando ; S. F. S., su- 
perior frontal sulcus ; P. C., precentral sulcus (verti- 
cal) and inferior frontal sulcus (horizontal); Sy. A., 
anterior limb of the Sylvian fissure; Sy. P., posterior 
limb of the Sylvian fissure ; S. S., subordinate sulcus 
separating area of absolute adduction of vocal chords. 
(Horsley.)] CEREBRUM, UNDER SURFACE. 
687 
The parieto-occipital fissure on the upper surface of the cerebrum is a short fissure 
about an inch long, at a right angle to the great longitudinal fissure, and two to 
three millimeters in front of the lambda. 
The convolutions are mapped out so soon as we have fixed the sulci as above 
described, and it is not needful to enter into further details. The localization of 
function has been already stated (p. 681). 
In estimating the motor value of the convolutions it must be remembered that the 
so-called motor cells are not found in the gray matter of the sulci deeper than the 
thickness of the cortical layer proper, and that faradism of the walls and floor of a 
sulcus evokes no movement. This function seems limited to the surface layer 
entirely.] 
Cerebrum, Under Surface or Base (Fig. 466). 
The under surface of each hemisphere presents a subdivision, as already men- 
tioned, into three lobes, named, from their position, anterior, middle, and posterior. 
The anterior or frontal lobe, of a triangular form, with its apex backward, is 
somewhat concave, and rests upon the convex surface of the roof of the orbit, being 
separated from the middle lobe by the fissure of Sylvius. The middle lobe, which 
is more prominent, is received into the middle fossa of the base of the skull, and 
comprises the parietal and temporo-sphenoidal lobes. The posterior or occipital lobe 
rests upon the tentorium, its extent forward being limited by the anterior margin 
of the cerebellum. 
The various objects exposed to view on the under surface of the cerebrum in and 
near the middle line are here arranged in the order in which they are met with from 
before backward: 
Longitudinal fissure. 
Corpus callosum and its peduncles. 
Lamina cinerea. 
Olfactory nerve. 
Fissure of Sylvius. 
Anterior perforated space. 
Optic commissure. 
Tuber cinereum. 
Infundibulum. 
Pituitary body. 
Corpora albicantia. 
Posterior perforated space. 
Crura cerebri. 
The longitudinal fissure partially separates the two hemispheres from one 
another: it divides the two anterior lobes in front, and on raising the cerebellum 
and pons it will be seen completely separating the two posterior lobes, the inter- 
mediate portion of the fissure being filled up by the great transverse band of white 
matter, the corpus callosum. Of these two portions of the longitudinal fissure, that 
which separates the posterior lobes is the longer. In the fissure between the two 
anterior lobes the anterior cerebral arteries may be seen ascending on the corpus 
callosum, and at the back part of this portion of the fissure the anterior curved por- 
tion of the corpus callosum descends to the base of the brain. 
The corpus callosum terminates at the base of the brain by a concave margin, 
which is connected with the tuber cinereum through the intervention of a thin layer 
of gray substance, the lamina cinerea. This may be exposed by gently raising and 
drawing back the optic commissure. A broad white band may be observed on each 
side passing from the under surface of the corpus callosum backward and outward 
to the commencement of the fissure of Sylvius; these bands are called the pedun- 
cles of the corpus callosum. They may be traced upward around the genu to 
become continuous with the strice longitudinales or nerves of Lancisi on the upper 
surface of the corpus callosum (Fig. 467, p. 691). Laterally, the corpus callosum 
extends into the anterior lobe. [It is the great transverse commissure connecting 
the two hemispheres.] 
The lamina cinerea is a thin layer of gray substance extending backward 
above the optic commissure from the termination of the corpus callosum to the tuber 
cinereum; it is continuous on either side with the gray matter of the anterior per- 
forated space, and forms the anterior part of the inferior boundary of the third 688 
THE NERVOUS SYSTEM. 
ventricle. It connects the genu or reflected portion of the corpus callosum with the 
optic commissure, and is on this account described by Sappey as the gray root of 
the optic nerves. 
The olfactory nerve, with its bulb, is seen on either side of the longitudinal 
fissure upon the under surface of each anterior lobe. 
The fissure of Sylvius separates the anterior and middle lobes and lodges the 
middle cerebral artery. At its commencement is seen a point of medullary sub- 
Fig. 466. 
-FRONTAL LOBE 
TEMPORO-SPHE' 
NOIDAL LOBE 
HIPPOCAMPAL 
FISSURE 
_LINGUAL 
LOBULE 
[occipital lobe 
Base of the Brain. 
stance, corresponding to a subjacent band of white fibres, connecting the frontal 
and temporo-sphenoidal lobes, and called the fasciculus unciformis; on following 
this fissure outward it divides into two branches, which enclose the triangular- 
shaped prominent cluster of isolated convolutions called the island of Reil {gyri 
opertif 
The anterior perforated space (substantia perforata) is situated at the inner 
side of the fissure of Sylvius. It is of a triangular shape, bounded in front by the 
convolutions of the anterior lobe and the roots of the olfactory nerve; behind by 
the optic tract; externally by the middle lobe and commencement of the fissure of 
Sylvius; internally, it is continuous with the lamina cinerea and crossed by the 
peduncle of the corpus callosum. It is of a grayish color, and corresponds to the 
under surface of the corpus striatum, a large mass of gray matter situated in the 
interior of the brain; it has received its name from being perforated by numerous CEREBRUM, UNDER SURFACE. 
689 
minute apertures for the transmission of small straight vessels into the substance of 
the corpus striatum. 
The optic commissure is situated in the middle line immediately in front of the 
tuber cinereum and below the lamina cinerea.1 It is the point of junction between 
the two optic nerves. 
Immediately behind the diverging optic tracts, and between them and the pedun- 
cles of the cerebrum (crura cerebri}, is a lozenge-shaped interval, the interpedun- 
cular space, in which are found the following parts: the tuber cinereum, infundib- 
ulum, pituitary body, corpora albicantia, and the posterior perforated space. 
The tuber cinereum is an eminence of gray matter situated between the optic 
tracts and the corpora albicantia; it is connected with the surrounding parts of 
the cerebrum, forms part of the floor of the third ventricle, and is continuous with 
the gray substance in that cavity. From the middle of its under surface a conical 
tubular process of gray matter, about two lines in length, is continued downward 
and forward, to be attached to the posterior lobe of the pituitary body ; this is 
the infundibulum. Its canal, which is funnel-shaped, communicates with the third 
ventricle. 
The pituitary body (hypophysis cerebri} is a small reddish-gray vascular mass, 
weighing from five to ten grains and of an oval form, situated in the sella Turcica, 
in connection with which it is retained by a process of dura mater derived from 
the inner wall of the cavernous sinus. This process covers in the pituitary fossa, 
enclosing the pituitary body and having a small hole in its centre through which 
the infundibulum passes. It is very vascular and consists of two lobes, separated 
from one another by a fibrous lamina. Of these, the anterior is the larger, of an 
oblong form and somewhat concave behind, where it receives the posterior lobe, 
which is round. The two lobes differ both in development and structure. The 
anterior lobe, of a dark, yellowish-gray color, is developed from the ectoderm of 
the buccal cavity, and resembles to a considerable extent, in microscopic structure, 
the thyroid body. It consists of a number of isolated vesicles and slightly convo- 
luted alveoli lined by epithelium and united together by connective tissue. The 
epithelium is columnar and occasionally ciliated. The alveoli sometimes contain 
a colloid material similar to that found in the thyroid body, and their walls are 
surrounded by a close network of lymphatics and capillary blood-vessels. The pos- 
terior lobe is developed by an outgrowth from the embryonic brain, and during 
foetal life contains a cavity which communicates through the infundibulum with the 
cavity of the third ventricle. In the adult it becomes firmer and more solid, and 
consists of a sponge-like connective tissue arranged in the form of reticulating 
bundles, between which are branched cells, some of them containing pigment. In 
the lower animals the two lobes are quite distinct, and it is only in the Mammalia 
that they become connected together. 
The corpora albicantia oi' mamillaria are two small round white masses, each 
about the size of a pea, placed side by side immediately behind the tuber cinereum. 
They are formed by the anterior crura of the fornix, hence called the hdbs of the 
fornix, which, after descending to the base of the brain, are folded upon themselves 
before passing upward to the thalami optici [Fig. 466, and Fig. 475, p. 701]. 
They are composed externally of white substance and internally of gray matter, 
the gray matter of the two being connected by a transverse commissure of the 
same material. At an early period of foetal life they are blended together into one 
large mass, but become separated about the seventh month. 
The posterior perforated space (pons Tarini} corresponds to a whitish-gray 
substance placed between the corpora albicantia in front, the pons Varolii behind, 
and the crura cerebri on either side. It forms the back part of the floor of the 
third ventricle, and is perforated by numerous small orifices for the passage of 
blood-vessels to the optic thalami. 
The crura cerebri (peduncles of the cerebrum) are two thick cylindrical bun- 
1 That is to say, the commissure is superficial to the lamina in the order of dissection when the. 
base is uppermost. 690 
THE NERVOUS SYSTEM. 
dies of white matter which emerge from the anterioi- border of the pons and diverge 
as they pass forward and outward to enter the under part of either hemisphere. 
Each crus is about three-quarters of an inch in length and somewhat broader in 
front than behind. They are marked upon their surface with longitudinal striae, 
and each is crossed, just before entering the hemisphere, by a flattened white band, 
the optic tract, which is adherent by its upper border to the peduncle. In the 
interior of the crura is contained a mass of dark gray matter called locus niger. 
The third nerve may be seen emerging from the inner side of either crus, and the 
fourth nerve winding round its outer side from above. 
Each crus consists of a superficial and a deep layer of longitudinal white fibres 
continued upward from the pons: these layers are separated from each other by the 
locus niger. 
The superficial longitudinal fibres are named the crusta. They consist of coarse 
fasciculi of nerve-fibres, which are collected on the under or free surface of the crus, 
and pass from the margin of the pons Varolii to the internal capsule and the cere- 
bral hemisphere. 
The deep longitudinal fibres or tegmentum form the posterior or deeper part of 
the crus cerebri. They consist of small masses of gray substance separated by 
longitudinal fibres, forming a well-marked formatio reticularis similar to that found 
in the pons and medulla, and with which it is connected. The longitudinal fibres 
are continuous with those of the pons derived from the olivary body and from the 
lateral and posterior columns of the medulla, and include fibres derived from the 
superior peduncle of the cerebellum. They enter the optic thalamus, in which some 
terminate, and others are continued through it into the cortex of the hemispheres. 
The locus niger is a mass of gray matter situated between the superficial and 
deep layers of fibres above described. It is placed nearer the inner than the outer 
side of the crus. It contains small multipolar ganglion-cells, in which are lodged 
numerous dark pigment-granules. 
The posterior lobes of the cerebrum are concealed from view by the upper sur- 
face of the cerebellum and pons Varolii. When these parts are removed the two 
hemispheres are seen to be separated by the great longitudinal fissure, this fissure 
being interrupted by the posterior rc unded border of the corpus callosum. 
General Arrangement of the Parts composing the Cerebrum. 
As the peduncles or crura of the cerebrum enter the hemispheres they diverge 
from one another so as to leave an interval between them, the interpeduncular space. 
As they ascend, the component fibres of each pass through two large masses of gray 
matter, the ganglia of the brain, called the thalamus opticus and corpus striatum, 
which project as rounded eminences from the upper and inner side of each peduncle. 
The hemispheres are connected together, above these masses, by the great transverse 
commissure, the corpus callosum, and the interval left between its under surface, 
the upper surface of the ganglia, and the parts closing the interpeduncular space 
forms the general ventricular cavity. The upper part of this cavity is subdivided 
into two by a vertical septum, the septum lucidum, and thus the two lateral ven- 
tricles are formed. The lower part of the cavity forms the third ventricle, which 
communicates with the lateral ventricles above and with the fourth ventricle behind. 
The fifth ventricle is the interval left between the two layers composing the septum 
lucidum. 
Interior of the Cerebrum. 
If the upper part of either hemisphere is removed with a scalpel, about half an 
inch above the level of the corpus callosum its internal white matter will be exposed. 
It is an oval-shaped centre of white substance surrounded on all sides by a narrow 
convoluted margin of gray matter which presents an equal thickness in nearly every 
part. This white central mass has been called the centrum ovale minus. Its sur- 
face is studded with numerous minute red dots (ppuncta vasculosa), produced by the 
escape of blood from divided blood-vessels. In inflammation or great congestion of INTERIOR OF THE CEREBRUM. 
691 
the brain these are very numerous and of a dark color. If the remaining portion 
of one hemisphere is slightly separated from the other, a broad band of white sub- 
stance will be observed connecting them at the bottom of the longitudinal fissure; 
this is the corpus callosum. The margins of the hemispheres, which overlap this 
portion of the brain, are called the labia cerebri. Each labium is part of the con- 
volution of the corpus callosum {gyrus fornicatus\ already described, and the space 
between it and the upper surface of the corpus callosum has been termed the ven- 
tricle of the corpus callosum (Fig. 472, 2). 
The hemispheres should now be sliced off to a level with the corpus callosum, 
when the white substance of that structure will be seen connecting the two hemi- 
Fig. 467. 
Section of the Brain, made on a level with the Corpus Callosum. 
spheres. The large expanse of medullary matter now exposed, surrounded by the 
convoluted margin of gray substance, is called the centrum ovale majus of Vieussens. 
The Corpus Callosum is a thick stratum of transverse fibres exposed at the 
bottom of the longitudinal fissure. It connects the two hemispheres of the brain, 
forming their great transverse commissure, and forms the roof of a space in the 
interior of each hemisphere, the lateral ventricle. It is about four inches in length, 
extendino- to within an inch and a half of the anterior and to within two inches 
and a half of the posterior part of the brain. It is somewhat broader behind than 
in front, and is thicker at either end than in its central part, being thickest behind. 
It presents a somewhat arched form (Fig. 475, 5, p. 701) from before backward, ter- 
minating anteriorly in a rounded border which curves downward and backward be- 
tween the anterior lobes to the base of the brain. In its course it forms a distinct 
bend, named the genu, and is then continued downward and backward to the base of 
the brain, where it is connected, through the lamina cinerea, with the tuber cinereum. 692 
THE NERVOUS SYSTEM. 
The reflected portion of the corpus callosum is called the beak or rostrum; it be- 
comes gradually narrower as it descends, and is attached by its lateral margins to 
the frontal lobes. At its termination the corpus callosum gives off two bundles of 
white substance, which, diverging from one another, pass backward, across the ante- 
rior perforated space, to the entrance of the fissure of Sylvius. They are called the 
peduncles of the corpus callosum. Posteriorly, the corpus callosum forms a thick 
rounded fold called the splenium or pad, which is free for a little distance as it 
curves forward, and is then continuous with the fornix. On its upper surface the 
fibrous structure of the corpus callosum is very apparent, being collected into coarse 
transverse bundles. Along the middle line is a linear depression, the raphe, bounded 
laterally by two or more slightly elevated longitudinal bands, called the strice longi- 
tudinales or nerves of Lancisi; and still more externally other longitudinal strife 
are seen beneath the convolutions which rest on the corpus callosum. These are 
the strice longitudinales laterales. The under surface of the corpus callosum is 
continuous behind with the fornix, being separated from it in front by the septum 
lucidum, which forms a vertical partition between the two ventricles. On either 
side the fibres of the corpus callosum penetrate into the substance of the hemi- 
spheres, and connect together the anterior, middle, and part of the posterior lobes. 
It is the large number of fibres derived from the anterior and posterior lobes which 
explains the great thickness of the two extremities of this commissure. 
An incision should now be made through the corpus callosum, on either side of the raphe, 
when two large irregular-shaped cavities will be exposed which extend through a great part of 
the length of each hemisphere. These are the lateral ventricles. 
The lateral ventricles are serous cavities formed by the upper part of the gen- 
eral ventricular space in the interior of the brain. They are lined by a thin, 
diaphanous lining membrane covered by nu- 
cleated epithelium (the ependyma}, with cilia 
scattered here and there in patches. It is 
moistened by a serous fluid, which is some- 
times, even in health, secreted in considerable 
quantity. These cavities are two in number, 
one in each hemisphere, and they are separated 
from each other by a vertical septum, the sep- 
tum lucidum. 
Each lateral ventricle consists of a central 
cavity or body, and three smaller cavities or 
cornua which extend from it in different di- 
rections. The anterior cornu curves forward 
and outward into the substance of the anterior 
lobe. The posterior cornu, called the digital 
cavity, curves backward into the posterior lobe. 
The middle cornu descends into the middle 
lobe. 
The central cavity, or body of the lateral 
ventricle, is triangular in form. It is bounded 
above by the under surface of the corpus cal- 
losum, which forms the roof of the cavity. 
Internally is a vertical partition, the septum 
lucidum, which separates it from the opposite 
ventricle and connects the under surface of the 
corpus callosum with the fornix. Its floor is 
formed by the following parts enumerated in 
their order of position from before backward : 
the corpus striatum, tcenia semicircularis, optic 
thalamus, choroid plexus, corpus fimbriatum, 
and fornix. 
[Fig. 468. 
Cast showing Form of the Cavities (ventricles) in 
n^ewt^rior/c^^ornau^osteriorr?cci%om'iiCin- 
ferior. hi. Third ventricle; fm, foramen of 
Monro; AQ, aqueduct of Sylvius, or iter e ter- 
tio ad quartumventricuium.lv, Fourth ventri- 
cle; C. VI. This line indicates the prolongation 
of the fourth ventricle into the ventricle of 
the cord (or sixth ventricle), or central canal 
(altered from F6r6).] INTERIOR OF THE CEREBRUM. 
693 
The anterior cornu is triangular in form, passing outward into the anterior lobe 
and curving round the anterior extremity of the corpus striatum. It is bounded 
above by the corpus callosum ; below and externally by the corpus striatum ; and 
in front by the reflected portion of the corpus callosum. 
The posterior cornu, or digital cavity, curves backward into the substance of the 
posterior lobe, its direction being backward and outward, and then inward. On its 
floor is seen a longitudinal eminence which is produced by the extension inward of 
the calcarine sulcus; this is called the hippocampus minor. Between the middle 
and posterior horns a smooth eminence is observed which varies considerably in size 
in different subjects. It is called the eminentia collateralis. 
The corpus striatum [Figs. 469, 470, 471, and 475] has received its name from 
the striped appearance which its section presents, in consequence of diverging white 
fibres being mixed with the gray matter which forms the greater part of its sub- 
[Fig. 469. 
Diagram of Human Brain in Transverse Vertical Section. 
1 pons Varolii; 2, 2, crura cerebri; 3, 3, internal capsule; 4, 4, corona radiata; 5, optic thalamus; 6, claustrum; 
' 7, corpus callosum ; 8, external capsule; c, corpus striatum (caudate nucleus); s, surcingle; l n, lenticular 
nucleus- Syl, fissure of Sylvius; Gf, gyrus fornicatus; f1, first frontal convolution; f2, second frontal con- 
volution; F3, third frontal convolution; t1, first temporal convolution; t2, second temporal convolution; 
t3, third temporal convolution; h, gyrus hippocampi; b, island of Reil (Dalton).] 
stance. The greater portion of this body is imbedded in the white substance 
of the hemisphere, and is therefore external to the ventricle. It is termed the 
extraventricular portion, or the nucleus lenticularis, and consists of three seg- 
ments ; a part, however, is visible in the ventricle and its anterior cornu; 
this is the intraventricular portion or the nucleus caudatus. The intraventric- 
ular portion [caudate nucleus] is a pear-shaped mass, of a gray color externally; 
its broad extremity is directed forward into the fore part of the body and ante- 
rior cornu of the* lateral ventricle: its narrow end [the tail or surcingle] is 
directed outward and backward [and continues in a curvilinear course into the 
roof of the descending horn of the ventricle, running forward to reach the amyg- 
dala. This last is an almost isolated mass of gray matter beneath the lenticular 
nucleus, and continuous with the deep-seated convolution of the temporal lobe]. 
It is covered by the serous lining of the cavity, and crossed by some veins of con- 
siderable size.' It is separated from the extraventricular portion by a lamina of 
white matter [the continuation of the white fibres of the cord and crura cerebri on 
their way to the surface of the cerebrum], which is called the internal capsule, 
which also separates the intraventricular portion of the corpus striatum from the 
optic thalamus. It is called internal capsule, in contradistinction to a lamina of 
W'hite matter which covers the outer surface of the extraventricular portion of the 694 
THE NERVOUS SYSTEM. 
corpus striatum, and which is known as the external capsule. This in its turn is 
covered by a thin layer of gray matter termed the claustrum, which presents ridges 
or furrows on its outer surface corresponding to the convolutions and sulci of the 
island of Reil, with which it is in relation. 
The taenia semicircularis is a narrow, whitish, semi-transparent band of medul- 
lary substance situated in the depression between the nucleus caudatus and optic 
thalamus. Anteriorly, it descends in connection with the anterior pillar of the for- 
nix ; behind, it is continued into the descending horn of the ventricle, where it 
enters a mass of gray matter, the nucleus amygdalce, at the bottom of the cornu. 
[Fig. 470. 
Horizontal Section of the Brain of a Child Nine Months of Age, the right side being at a somewhat 
lower level than the left half. 
J1, frontal, TS, temporo-sphenoidal, and 0, occipital lobes; Op, operculum; Tn, island of Reil; Cis, claustrum; 
third frontal convolution; Th, optic thalamus; TVC, caudate nucleus; NC', tail of caudate nucleus (surcin- 
gle) ; LN, lenticular nucleus; I, II, III, first, second, and third divisions of the lenticular nucleus; EK, external 
capsule; IK, posterior division, IK', anterior division, and K, knee of the internal capsule; ah, ph, anterior 
and posterior horns respectively of the lateral ventricles; gee, knee of the corpus callosum; sp, splenium; 
me, middle commissure; f, fornix; si, septum lucidum ; a, cornu ammonis (Flechsig).] 
Its surface, especially at its fore part, is transparent and dense in structure, and 
this was called by Tarinus the horny band. It consists of longitudinal white 
fibres, the deepest of which run between the corpus striatum and optic thalamus. 
Beneath it is a large vein (vena corporis striati) which receives numerous small 
veins from the surface of the corpus striatum and optic thalamus and joins the 
venae Galeni. 
The choroid plexus is a highly vascular, fringe-like membrane occupying the 
margin of the fold of pia mater (velum interpositum) in the interior of the brain. 
It extends in a curved direction across the floor of the lateral ventricle. In front, 
where it is small and tapering, it communicates with the choroid plexus of the oppo- 
site side through a large oval aperture, the foramen of Monro. Posteriorly, • it INTERIOR OF THE CEREBRUM. 
695 
descends into the middle horn of the lateral ventricle, where it joins with the pia 
mater through the transverse fissure. In structure it consists of minute and highly 
vascular villous processes composed of large round corpuscles, containing, besides a 
central nucleus, several yellowish granules and fat-molecules and covered by a single 
layer of flattened epithelium. The arteries of the choroid plexus enter the ven- 
tricle at the descending cornu, and, after ramifying through its substance, send 
branches into the substance of the brain. The veins of the choroid plexus termi- 
nate in the venae Galeni. 
The corpus fimbriatum (tcenia hippocampi') is a narrow, white, tape-like band 
situated immediately behind the choroid plexus. It is the lateral edge of the pos- 
Fig. 471. 
The Lateral Ventricles of the Brain. 
terior pillar of the fornix, and is attached along the inner border of the hippocam- 
pus major as it descends into the middle horn of the lateral ventricle. It may be 
traced as far as the crochet or hook of the uncinate convolution. 
The optic thalamus and fornix will be described when more completely exposed 
in a later stage of the dissection of the brain. 
o 
The middle cornu should now be exposed, throughout its entire extent, by introducing the 
little finger gently into it and cutting outward along the finger through the substance of the 
hemisphere, which should be removed to an extent sufficient to expose the entire cavity. 
The middle or descending cornu, the largest of the three, traverses the middle 
lobe of the brain, forming in its course a remarkable curve round the back of the 
optic thalamus. It passes at first backward, outward, and downward, and then 
curves round the crus cerebri forward and inward, nearly to the point of the middle 696 
THE NERVOUS SYSTEM. 
lobe, close to the fissure of Sylvius. Its upper boundary is formed by the medul- 
lary substance of the middle lobe and the under surface of the optic thalamus. Its 
lower boundary, or floor, presents for examination the following parts : the hippo- 
campus major, pes hippocampi, pes accessorius, corpus fimbriatum, choroid plexus, 
fascia dentata, transverse fissure. 
The hippocampus major, or cornu Ammonis (Fig. 473), so called from its 
resemblance to a ram's horn, is a white eminence, of a curved elongate form, 
extending throughout the entire length of the floor of the middle horn of the lateral 
Fig. 472. 
Transverse Vertical Section of the Brain, through the fore part of the foramen magnum, looked at 
from the front (after Hirschfeld and Leveille). 
1. Corpus callosum in relation with the falx and the 
cerebral hemispheres. 
2. Ventricle of the corpus callosum. 
3. Lateral ventricles. 
4. Hippocampus major, white externally and gray 
internally. 
5. Cerebellum,' separated from the cerebrum by the 
tentorium. 
6. Section through the corpora quadrigemina, aque- 
duct of Sylvius, and pons Varolii. 
1. Medulla oblongata, with the vertebral arteries and 
the anterior spinal branch in relation with it. 
8. Auditory nerve, passing into the meatus auditorius 
internus. 
9. Pneumogastric nerve, passing through the poste- 
rior lacerated foramen. 
10. Hypoglossal nerve, passing through the anterior 
condyloid foramen. 
11,12. Gray and white substance of the convolutions. 
The fibres of the corpus callosum are sh own radi- 
ating through the white to the gray substance. 
ventricle. At its lower extremity it becomes enlarged, and presents a number of 
rounded elevations with intervening depressions, which, from presenting some resem- 
blance to the paw of an animal, is called the pes hippocampi. If a transverse sec- 
tion is made through the hippocampus major (Fig. 472, 4), it will be seen that this 
eminence is produced by the extension inward of the dentate sulcus on the exterior 
of the brain. This sulcus is filled with gray substance, which projects along the 
free margin of the hippocampus major, forming a notched ridge, the fascia dentata. 
The hippocampus is covered on its ventricular surface by a thin lamina of gray 
matter which is continuous with the corpus fimbriatum of the fornix. 
The pes accessorius, or eminentia collateralis, has already been mentioned as 
a white eminence, varying in size, placed between the hippocampus major and hip- 
pocampus minor, at the junction of the posterior with the descending cornu. It is 
formed by the protrusion inward of the collateral fissure. INTERIOR OF THE CEREBRUM. 
697 
1 he corpus fimbriatum is the thin lateral margin of the posterior pillar of the 
fornix, prolonged, as already mentioned, from the central cavity of the lateral ven- 
tricle. 
Fascia Dentata [Fig. 473].-On separating the inner border of the corpus fim- 
briatum from the choroid plexus, and raising the edge of the former, a serrated band 
of gray substance, the edge of the gray substance of the dentate convolution, will 
be seen beneath it: this is the fascia dentata. Correctly speaking, it is placed 
external to the cavity of the descending cornu. 
The [continuation forward of the] transverse fissure [or fissure of Bichat, 
between the cerebrum and cerebellum] is seen on separating the corpus fimbriatum 
from the optic thalamus. It is situated beneath the fornix, extending from the 
middle line behind, downward on either side to the end of the descending cornu. It 
is of a horseshoe shape. Its horizontal portion is bounded above by the splenium 
Fig. 473. 
COLLATERALS J 
f. FASCIA 
[DENTATA 
MAJOjg 
fe-N-C-iNATg 
Gjjncin ate 
Process 
GREY MATTEgp 
OF 
HIPPO CAM P U Sj 
Transverse Section of the Middle Horn of the Lateral Ventricle (from a drawing by Mr. F. A. Barton). 
or rounded posterior extremity of the corpus callosum, and below by the corpora 
quadrigemina. Its lateral portions curve downward and forward, and are bounded 
below and in front by the crura cerebri and optic thalami; above and behind by 
the hippocampus major and the corpus fimbriatum of the fornix. Through this 
fissure the pia mater passes from the exterior of the brain into the ventricles to 
form the [velum interpositum and] the choroid plexuses. Where the pia mater pro- 
jects into the lateral ventricle beneath the edge of the fornix it is connected with 
the lining membrane of these cavities, so as to exclude all communication with the 
exterior of the brain. 
The septum lucidum (Fig. 476, 6) forms the internal boundary of the lateral 
ventricles. It is a thin, semi-transparent septum, attached above to the under sur- 
face of the corpus callosum; below to the anterior part of the fornix; and in front 
of this to the prolonged portion of the corpus callosum. It is triangular in form, 
broad in front and narrow behind, its surfaces looking toward the cavities of the 
ventricles. The septum consists of two laminae separated by a narrow interval, the 
fifth ventricle. 
Fifth Ventricle.-The fifth ventricle was originally a part of the great longi- 
tudinal fissure which has become shut off by the union of the hemispheres in the 
formation of the corpus callosum above and the fornix below. Its walls are there- 698 
THE NERVOUS SYSTEM. 
fore formed by the median wall of the hemispheres, and consist of an internal layer 
of gray matter derived from the gray matter of the cortex, and an external layer 
of white substance continuous with the white matter of the cerebral hemispheres. 
This is lined on its external surface by the ependyma of the lateral ventricle. The 
fifth ventricle is not lined by epithelium. In the foetus and in some animals this 
space communicates below with the third ventricle, but in the adult it forms a sepa- 
rate cavity.1 In cases of serous effusion in the ventricles the septum is often found 
softened and partially broken down. 
The fifth ventricle may be exposed by cutting through the septum and attached portion of 
the corpus callosum with scissors; after examining which, the corpus callosum should be cut 
across toward its anterior part, and the two portions carefully dissected, the one forward, the 
other backward, when the fornix will be exposed. 
Fig. 474. 
The Fornix, Velum Interpositum, and Middle or Descending Cornu of the Lateral Ventricle. 
The fornix (Figs. 471, 476) is a longitudinal lamella of white fibrous matter 
situated beneath the corpus callosum, with which it is continuous behind, but sepa- 
rated from it in front by the septum lucidum. It may be described as consisting 
of two symmetrical halves, one for either hemisphere. These two portions are joined 
together in the middle line, where they form the body, but are separated from one 
another in front and behind, forming the anterior and posterior crura. 
The body of the fornix is triangular, narrow in front, broad behind. Its upper 
surface is connected in the median line to the septum lucidum in front and the cor- 
pus callosum behind. Its under surface rests upon the velum interpositum, which 
separates it from the third ventricle and the inner portion of the optic thalami. Its 
[1 Wilder (N. Y. Med. Journ., 1884, xxxix. 458) states that at no time is there any communication 
between the third and the fifth ventricle.] INTERIOR OF THE CEREBRUM. 
699 
lateral edges form, on each side, part of the floor of the lateral ventricles, and are 
in contact with the choroid plexuses. 
The anterior crura arch downward toward the base of the brain, separated 
from each other by a narrow interval. They are composed of white which 
descend through a quantity of gray matter in the lateral walls of the third ventricle 
and are placed immediately behind the anterior commissure. At the base of the 
brain the white fibres of each crus form a sudden curve upon themselves, spread 
out and form the outer part of the corresponding corpus albicans, from which point 
they may be traced upward into the substance of the corresponding optic thalamus 
(Fig. 476). The anterior crura of the fornix are connected in their course with the 
peduncle of the pineal gland and the superficial fibres of the tsenia semicircularis, 
and receive fibres from the septum lucidum. 
The posterior crura at their commencement are intimately connected by their 
upper surfaces with the corpus callosum; diverging from one another, they pass 
downward into the descending horn of the lateral ventricle, being continuous with 
the concave border of the hippocampus major. The lateral thin edges of the pos- 
terior crura have received the name of corpus fimbriatum, already described. Upon 
examining the under surface of the fornix between its diverging posterior crura, 
a triangular portion of the under surface of the corpus callosum may be seen. On 
it are a number of lines, some transverse, others longitudinal or oblique. This 
appearance has been termed the lyra, from the fancied resemblance it bears to the 
strings of a harp. 
Between the anterior pillars of the fornix and the anterior extremities of the 
optic thalami an oval aperture is seen on each side, the foramen of Monro (Fig. 
475). The two openings descend toward the middle line, and, joining together, 
lead into the upper part of the third ventricle. These openings communicate with 
the lateral ventricles on each side and below with the third ventricle. 
Divide the fornix across anteriorly, and reflect the two portions, the one forward, the other 
backward, when the velum interpositum will be exposed. 
The velum interpositum (Fig. 474, and Fig. 476,10, p. 701) is a vascular mem- 
brane, a prolongation from the pia mater into the interior of the brain through the 
transverse fissure, passing beneath the posterior rounded border of the corpus callosum 
and fornix, and above the corpora quadrigemina, pineal gland, and optic thalami. It 
is of a triangular form, and separates the under surface of the body of the fornix from 
the cavity of the third ventricle. Its posterior border forms an almost complete in- 
vestment for the pineal gland. Its anterior extremity or apex is bifid, each bifurcation 
being continued into the corresponding lateral ventricle through the foramen of Monro, 
forming the anterior extremity of the choroid plexus. On its under surface are two 
vascular fringes, which diverge from each other behind and project into the cavity 
of the third ventricle. These are the choroid plexuses of the third ventricle. To 
its lateral margins are connected the choroid plexuses of the lateral ventricles. Of 
the arteries of the velum interpositum, some branches from the superior cerebellar 
and posterior cerebral enter from behind, beneath the corpus callosum ; another con- 
stant branch, the anterior choroid, enters the velum interpositum at the extremity 
of the middle horn of the lateral ventricle, and supplies this structure and the choroid 
plexus. Its veins, the vence Graleni, two in number, run between its layers; they 
are formed by the venae corporis striati and the veins of the choroid plexuses; the 
venae Galeni unite posteriorly into a single trunk, which terminates in the straight 
sinus (Fig. 412, p. 619). 
The velum interpositum should now be removed. This must be effected carefully, especially 
at its posterior part, where it invests the pineal gland; the optic thalami will then be exposed, 
with the cavity of the third ventricle between them (Fig. 475). 
The optic thalami are two large oblong masses placed between the diverging 
portions of the corpora striata; they are of a white color superficially; internally 
they are composed chiefly of gray matter. Each thalamus rests upon its correspond- 
ing crus cerebri, which it embraces. Externally, it is separated from the corpus 700 
THE NERVOUS SYSTEM. 
striatum by the internal capsule, through which it is continuous with the hemi- 
sphere. Internally, it forms the lateral boundary of the third ventricle, and run- 
ning along its upper border is seen the peduncle of the pineal gland. Its upper 
surface is free, being partly seen in the lateral ventricle; it is partially covered by 
the fornix, and marked in front by an eminence, the anterior tubercle. Its under 
surface forms the roof of the descending cornu of the lateral ventricle ; into it the 
crus cerebri passes. Its,posterior and inferior part, which projects into the descend- 
ing horn of the lateral ventricle, presents two small rounded eminences, the internal 
and external geniculate bodies. Its anterior extremity, which is narrow, forms the 
posterior boundary of the foramen of Monro. 
The third ventricle is the narrow oblong fissure placed between the optic thalami 
and extending to the base of the brain. It is bounded above by the under surface 
Fig. 475. 
The Third and Fourth Ventricles. An arrow [anteriorly] has been placed in the position of the foramen of 
Monro, [and another posteriorly passes through the iter a tertio ad quartum ventriculum]. 
of the velum interpositum, from which are suspended the choroid plexuses of the 
third ventricle, and laterally by two white tracts, one on either side, the peduncles 
of the pineal gland. Its floor, somewhat oblique in its direction, is formed, from 
before backward, by the parts which close the interpeduncular space-viz. the 
lamina cinerea, the tuber cinereum and infundibulum, the corpora albicantia, and 
the locus perforatus posticus; its sides, by the optic thalami; it is bounded in front 
by the anterior crura of the fornix and part of the anterior commissure; behind, by 
the posterior commissure and the iter a tertio ad quartum ventriculum. 
The cavity of the third ventricle is crossed by three commissures, named, from 
their position, anterior, middle, and posterior. INTERIOR OF THE CEREBRUM. 
701 
The anterior commissure is a rounded cord of white fibres placed in fror of the 
anterior crura of the fornix. It perforates the corpus striatum on either side, and 
spreads out into the substance of the hemispheres over the roof of the descending 
horn of each lateral ventricle. 
The middle or so/Z commissure consists almost entirely of gray matter. It con- 
nects together the optic thalami, and is continuous with the gray matter lining the 
Fig. 476. 
Vertical Median Section of the Encephalon, showing the parts in the middle line. 
1. Convolution of corpus callosum. Above it is the 
calloso-marginal fissure, running out to join at 
2. The fissure of Rolando. 
3. The parieto-occipital fissure. 
4. 4, point to the calcarine fissure, which is just above 
the numbers. Between 2 and 3 are the convolu- 
tions of the quadrate lobe. Between 3 and 4 is the 
cuneate lobe. 
5. The corpus callosum. 
6. The septum lucidum. 
7. The fornix. 
8. Anterior pillar of the fornix, descending to the base 
of the brain, and turning on itself to form the cor- 
pus albicans. Its course to the optic thalamus is 
indicated by a dotted line. 
9. The optic thalamus. Behind the anterior crus of the 
fornix (8) a shaded part indicates the foramen of 
Monro; in front of the number 9 an oval mark 
shows the position of the gray matter continuous 
with the middle commissure. 
10. The velum interpositum. 
11. The pineal gland, 
12. The corpora quadrigemina. 
13. The crus cerebri. 
14. [The iter e tertio ad quartum ventriculum. Be- 
tween 14 and the cerebellum is the valve of 
Vieussens, seen in profile, stretching between 
the two processus e cerebello ad testes. The pro- 
cessus e cerebello ad medullam is seen between 
21 and the cerebellum.] 
15. The pons Varolii. 
16. The third nerve. 
17. The pituitary body. 
18. The optic nerve. 
19 points to the anterior commissure, indicated by an 
oval mark behind the number. 
[20. The transverse fissure of Bichat. 
21. The fourth ventricle.] 
anterior part of the third ventricle. It is frequently broken in examining the brain, 
and might then be supposed to have been wanting. 
The posterior commissure, smaller than the anterior, is a flattened white band of 
fibres connecting together the two optic thalami posteriorly. It bounds the third 
ventricle posteriorly, and is placed in front of and beneath the pineal gland, above 
the opening leading to the fourth ventricle. 
The third ventricle has four openings connected with it (Figs. 468,471, and 476). In 
front are the two oval apertures of the foramina of Monro, one on either side, through 
which the third communicates with the lateral ventricles. Behind is a third opening 
leading into the fourth ventricle by a canal, the aqueduct of Sylvius, or iter a tertio 702 
THE NERVOUS SYSTEM. 
ad quantum ventriculum. The fourth, situated in the anterior part of the floor of 
the ventricle, is a deep pit which leads downward to the funnel-shaped cavity of 
the infundibulum (iter ad infundibulum). 
The lining membrane of the lateral ventricles is continued through the foramen 
of Monro into the third ventricle, and extends along the iter a tertio into the fourth 
ventricle; at the bottom of the iter ad infundibulum it ends in a cul-de-sac. 
The foramen of Monro is the means by which the two lateral ventricles com- 
municate with the third ventricle. It may be regarded as a Y-shaped passage, the 
two upper diverging limbs communicating with the lateral ventricles respectively, 
and joining below to open into the third ventricle. Its roof is formed by the ante- 
rior extremity of the body of the fornix, which, dividing into its two crura, arches 
downward in front of the anterior extremity of the optic thalami. The crus is not, 
however, in contact with the thalamus, but an interval is left between the two, which 
is the foramen of Monro. Its boundaries are, therefore, in front, the anterior pillars 
of the fornix ; behind, the anterior extremity of the optic thalamus ; above, the body 
of the fornix ; and below, the groove where the corpus striatum and optic thalamus 
meet. 
Behind the third ventricle and in front of the cerebellum are the corpora quad- 
rigemina, and, resting upon these, the pineal gland. 
The pineal gland (epiphysis cerebri), so named from its peculiar shape (pinus, 
a fir-cone), is a small reddish-gray body, conical in form (hence its synonym, cona- 
rium), placed immediately behind the posterior commissure and between the nates, 
upon which it rests. It is retained in its position by a duplicature of pia mater 
derived from the under surface of the velum interpositum, which almost completely 
invests it. The pineal gland is about four lines in length and from two to three in 
width at its base, and is said to be larger in the child than in the adult, and in the 
female than in the male. Its base is connected to the cerebrum by two peduncles 
(the peduncles of the pineal gland), which pass forward upon the upper and inner 
margin of the optic thalami to the anterior crura of the fornix, with which they 
become blended: these two peduncles join together at their posterior extremity in 
front of the pineal gland, forming a sort of festoon, and the base of the gland is 
connected to their posterior margin at the point of junction. In front the band of 
union is j oined to the back of the posterior commissure. The pineal gland consists 
of a number of follicles lined by epithelium and connected together by ingrowths 
of connective tissue. The follicles contain a transparent viscid fluid and a quan- 
tity of sabulous matter, named acervulus cerebri, composed of phosphate and car- 
bonate of lime, phosphate of magnesia, and ammonia, with a little animal matter. 
These concretions are almost constant in their existence and are found at all periods 
of life. When this body is solid the sabulous matter is found upon its surface and 
occasionally upon its peduncles. 
On the removal of the pineal gland and adjacent portion of pia mater the corpora quadri- 
gemina are exposed. 
The corpora or tubercula quadrigemina (optic lobes) are four rounded emi- 
nences placed in pairs, two in front and two behind, and separated from one another 
by a crucial depression. They are situated immediately behind the third ventricle 
and posterior commissure, beneath the posterior border of the corpus callosum, and 
above the iter a tertio ad quartum ventriculum. The anterior pair, the nates, are 
the larger, oblong from before backward, and of a gray color. The posterior pair, 
the testes, are hemispherical in form and lighter in color than the preceding. They 
are connected on each side with the optic thalamus and commencement of the optic 
tracts by means of two white prominent bands termed brachia. Those connecting 
the nates with the thalamus (brachia anteriora) are the larger and pass obliquely 
outward. Those connecting the testes with the thalamus are called the brachia 
posteriora. Both pairs, in the adult, are quite solid, being composed of white 
matter externally and gray matter within. These bodies are larger in the lower 
animals than in man. In fishes, reptiles, and birds they are only two in number, INTERIOR OF THE CEREBRUM. 
703 
are called the optic lobes from their connection with the optic nerves, and are hol- 
low in their interior; but in Mammalia they are four in number, as in man, and 
quite solid. In the human foetus they are developed at a very early period, and 
form a large proportion of the cerebral mass; at first they are only two in number, 
as in the lower Vertebrata, and hollow in their interior. 
These bodies receive, from below, white fibres from the olivary fasciculus or 
fillet; they are also connected with the cerebellum by means of a large white cord 
on each side, the processus e cerebello ad testes, or superior peduncles of the cere- 
bellum, which is continued onward to the thalami through the tubercula quadri- 
gemina. 
The valve of Vieussens, or anterior medullary velum, is a thin translucent 
lamina of white matter, marked superficially by a few transverse streaks of gray 
substance, stretched between the two processus e cerebello ad testes; it covers in 
the canal leading from the third to the fourth ventricle, forming part of the roof of 
the latter cavity. It is narrow in front, where it is connected with the testes, and 
broader behind, at its connection with the vermiform process of the cerebellum. A 
slight elevated ridge, the frcenulum, descends upon the upper part of the valve from 
the corpora quadrigemina, and on either side of it may be seen the fourth nerve, 
which is connected with its fellow of the opposite side by a transverse band of 
fibres forming a partial decussation. Its lower half is covered by a thin trans- 
versely-grooved lobule of gray matter prolonged from the anterior border of the 
cerebellum: this is called by the Italian anatomists the linguetta laminosa. 
The corpora geniculata are two small, flattened, oblong masses placed on the 
outer side of the corpora quadrigemina and on the under and back part of each 
optic thalamus, and named, from their position, corpus geniculatum externum and 
internum. The two bodies are separated from one another by one of the roots of 
the optic tract. 
Internal Structure of the Cerebrum.-The cerebrum, like the other parts of 
the great nerve-centre, is composed of gray and white matter. In order to give some 
general idea of its construction, at all events in part, it may be compared, for the 
sake of illustration, to a tree, the trunk of which divides into two main branches, 
and these break up into smaller branches, which finally end in twigs, to which are 
attached the leaves, forming an investment to the branches and covering the whole 
tree. The trunk is represented by the medulla oblongata as it passes through the 
foramen magnum; the two main branches, by the crura cerebri, which break up 
into smaller branches, which diverge from each other, dividing and subdividing, 
until they reach the surface of the hemispheres, where they terminate in single 
nerve-fibres, to which are attached the basal axial cylinder processes of the nerve- 
cells, represented by the leaves. These cells are arranged on the surface, resem- 
bling a cap covering the hemispheres, and constitute the cerebral cortex. But here 
the analogy ends, for in the cerebrum we have, in addition to this cortex, other 
masses of gray matter situated in the middle of the brain, and other white fibres 
besides these diverging ones which have been mentioned, and which serve either to 
connect together the two hemispheres of which the cerebrum consists, or else serve 
to connect different structures in the same hemisphere. 
The gray matter of the cerebrum is disposed in three great groups: 1, the gray 
matter of the cerebral cortex; 2, the gray matter of the basal ganglia-that is, the 
great ganglia of the base of the cerebrum; 3, the gray matter which lines the inter- 
nal surface of the upper part of the cerebro-spinal tube-that is, the remains of the 
cavity in the original vesicles from which the brain was formed, and which consti- 
tutes the central cavities of the organ. 
1. The gray matter of the cortex (Fig. 477) invests the surface of the hemi- 
spheres and gives them external form. M hen vertical sections are made through 
it and examined microscopically, it is found to consist of five separate layers, but 
to this there are some exceptions. According to Meynert, these are to be found 
in the posterior portion of the occipital lobe, in the gray cortex of the hippocampus 
major, in the wall of the fissure of Sylvius, and in the olfactory bulb. The five 704 
THE NERVOUS SYSTEM. 
layers in the common type are as follows: (1) The first layer is principally com- 
posed of a matrix or neuroglia, through which a few small ganglion-cells are irreg- 
ularly distributed, and a nerve-fibre network. (2) The second layer consists of 
numerous small pyramidal cells, which have their long axes vertical to the surface 
of the convolutions, and are closely aggregated together, so as to completely fill 
the layer with a number of closely-compressed cells. 
(3) The third layer is named by Meynert the for- 
mation of the cornu ammonis, as it is made up of 
cells, which are the only morphological element 
found in this part. It consists of the same sort 
of pyramidal cells, arranged vertically to the sur- 
face, as was found in the preceding layer, but they 
are of very much larger size, and increase pro- 
gressively toward the deeper parts of the layer, 
and they are much more widely separated from 
each other. This layer is the principal and 
broadest one of the series, and is at least twice 
as deep as the preceding layer. (4) The fourth 
layer is termed the granular formation by Mey- 
nert, and consists of numerous ■small, irregular, 
rarely triangular or elongated cells, which resem- 
ble the nerve-corpuscles found in the internal 
granule-layer of the retina, and which are closely 
aggregated together. (5) The fifth layer is termed 
the claustral formation, and consists of a very 
large proportion of spindle-shaped cells, which are 
the peculiar elements of this layer. They are es- 
pecially numerous in the inner half, and are ar- 
ranged horizontally, extending parallel to the sur- 
face. They have received their name from the 
fact that the claustrum is made up almost entirely 
of an accumulation of these cells. It will be seen, 
therefore, that the differences in these layers de- 
pends upon the varying form and size of these cells 
and the closeness of their arrangement, and that 
the typical form of cell, and the only one which is 
admitted by some observers, is the pyramidal cell 
or nerve-corpuscle. These nerve-corpuscles are 
destitute of a cell-wall; they present a nucleus, 
sometimes round or oval, sometimes angular, and 
give off many processes. One of these, which, in 
the cells arranged vertically to the surface, pro- 
jects outward and is named the process of the 
apex, is strong and branched, and according to 
Cleland is continuous with the nerve-fibre network 
in the first or superficial layer of the cortex. An- 
other process projects inward toward the white 
matter of the hemisphere and from the opposite extremity of the cell. It is termed 
the process of the centre of the base. It is more slender than the preceding and 
remains unbranched. It is an axis-cylinder process, and, becoming invested with a 
medullary sheath, constitutes a nerve-fibre extending into the central white matter. 
In addition to these, lateral processes are given off, forming the processes of the 
basal angle, which can be traced for a longer or shorter distance and break up into 
a network of extremely minute nerve-fibres. 
Special Types of the Cray Matter of the Cortex.-According to Meynert, the 
gray matter on the summit of the occipital lobe consists of eight layers. This is 
produced by the intercalation of intermediate granule-layers similar to those form- 
Fig. 477. 
Gray Matter of the Cerebral Cortex 
(Meynert). INTERIOR OF THE CEREBRUM. 
705 
ing the fourth layer of the typical cortex. In the gray matter of the cortex of the 
hippocampus major or cornu ammonia pyramidal cells are alone formed, such as 
have been described in the third layer of the typical cortex. This constitutes the 
greater part of the structure in this situation, the fourth and fifth layers being 
absent and the second layer containing no cells. In the wall of the Sylvian fissure 
the gray matter is termed the claustrum, and part of it separates the island of Reil 
from the external capsule of the corpus striatum. This presents peculiarities of 
structure, consisting mainly of fusiform cells, such as constitute the fourth layer. 
The olfactory bulb, which may be regarded as a portion of the cerebral hemispheres, 
forming "a cap superimposed upon a conical process of the cerebrum," presents 
another variety of structure, differing from the type of the cortex of the hemi- 
spheres. The bulb consists of both gray and white matter, and sometimes retains 
a central cavity lined by epithelium. The lower part is gray matter, and consists 
of the following layers from below upward: (1) The olfactory nerve-layer, consist- 
ing of a layer of non-medullated nerve-fibres derived from the nerves which supply 
the olfactory region. (2) The stratum glomerulosum, consisting of nodulated masses, 
containing small nuclear cells and a convoluted olfactory nerve-fibre amongst the 
cells. (3) The stratum gelatinosum, consisting of fusiform or pyramidal nerve-cells 
and a fine network of nerve-fibre. (4) The granular layer, consisting of small 
irregular nerve-cells resembling the fourth layer of the cerebellum or the granular 
layer of the retina. 
2. The Gray Matter of the Basal Ganglia.-The great ganglia of the base of 
the brain are the optic thalamus, the corpus striatum, the corpora quadrigemina, the 
corpora geniculata, and the locus niger. Only a part, however, of the gray matter 
of the corpora quadrigemina, that found on the periphery of the body, belongs to 
this group; the remainder, that contained in its centre around the Sylvian aqueduct, 
belongs properly to the third group, which will be discussed immediately. 
The optic thalamus is chiefly formed of gray matter, covered over by a super- 
ficial layer of white, which on the outer side separates it from the internal capsule. 
The gray matter is arranged in two masses, the outer and inner nuclei, partially 
divided by a vertical white septum. It is traversed by numerous nerve-fibres, 
which for the most part have no definite direction; some, however, converge and 
form a bundle which passes downward to form the anterior root of the fornix. It 
contains comparatively large nerve-cells, both multipolar and fusiform. The inner 
nucleus is connected across the middle line with the inner nucleus of the opposite 
side by the middle commissure of the third ventricle, which, however, belongs to 
the third group of gray matter. 
The corpus striatum presents two distinct and separate masses-the nucleus cau- 
datus, which is the intraventricular portion of the corpus striatum; and the nucleus 
lenticularis, which is the extraventricular portion. The two are separated from each 
other by a distinct lamina of white matter, the internal capsule, which also separates 
the nucleus lenticularis from the outer part of the optic thalamus. The gray matter 
of the corpus striatum is permeated by tracts of medullated nerve-fibres, some of 
which probably originate in it, though the actual connection of the nerve-fibres with 
the cells has not been demonstrated. The nerve-cells are multipolar, both large and 
small, the larger being principally found in the lenticular nucleus. 
The corpora quadrigemina consists of two distinct and separate collections of 
gray matter, one at or near the surface, which belongs to the basal ganglia, and one 
in the centre lining the aqueduct of Sylvius. The former only will be considered 
at present. The peripheral gray matter of the corpora quadrigemina differs some- 
what in the anterior and posterior lobes. The posterior lobes or testes are composed 
almost entirely of gray matter, covered over by a thin stratum of white matter, and 
separated from the central gray matter by tracts of transverse white fibres derived 
from and forming part of the fillet. The anterior lobes or nates are covered super- 
ficially by a thin stratum of white matter; beneath this is a layer of gray matter 
termed the stratum cinerum, and consisting, as well as the gray matter of the pos- 
terior lobes, of small multipolar cells imbedded in a fine network of nerves. Beneath 706 
THE NERVOUS SYSTEM 
this again is a characteristic mass of gray matter, termed the stratum opticum, which 
is made up of fine nerve-fibres coursing in a longitudinal direction, and containing 
between them small masses of gray substance consisting of small multipolar nerve- 
cells imbedded in gray matter. Lastly, between this body and the central gray 
matter around the Sylvian aqueduct is a thin lamina of white matter, derived from 
the fillet. 
The geniculate bodies are continuous with the gray substance of the optic thala- 
mus, and the external one (corp, geniculatum externum) is peculiar on account of 
its dark color, due to its cells containing pigment. It presents a laminated arrange- 
ment, and consists of alternate thick layers of gray matter and thin layers of white 
matter. Its cells are multipolar. The internal body (corp, geniculatum internum) 
is of lighter color, does not present a laminated arrangement, and its cells are smaller 
in size and fusiform in shape. 
The locus niger, or gray matter of the crus cerebri, like the external geniculate 
body, is peculiar from the large amount of dark pigment-granules which are con- 
tained in its ganglion-cells, and which give to it its dark color, from which it has 
derived its name. Its cells are small and multipolar. 
3. The central gray matter of the cerebrum lines the upper part of the cere- 
bro-spinal tube, which is the remains of the cavity in the original vesicles from which 
the brain was formed, and is continuous with the gray matter of the floor of the fourth 
ventricle, and through it with the gray matter of the cord [which surrounds the " ven- 
tricle of the cord" or central canal]. This central gray matter is found lining the 
aqueduct of Sylvius, by which the third communicates with the fourth ventricle; it 
covers the inner wall of each optic thalamus, forming the middle or gray commissure 
of the third ventricle; it also lines the floor of the third ventricle; it covers behind 
the upper surface of the tegmentum of the crus, and in front it approaches the sur- 
face of the brain, forming the posterior perforated space and the lamina cinerea. It 
forms also the tuber cinereum and the infundibulum, and in the lower Vertebrata, 
especially fishes, the posterior lobe of the pituitary body. In the higher vertebrates 
this lobe does not present any nervous structure, being encroached upon and oblit- 
erated by an ingrowth of connective tissue and vessels. The gray matter surround- 
ing the Sylvian aqueduct, which has been before mentioned as the central gray 
matter of the corpora quadrigemina, presents some features requiring especial men- 
tion. It forms a tolerably thick layer surrounding the canal, but is thicker on the 
lower wall-that is, below the canal-than above. The cells, which are multipolar, 
are here collected into groups, and form nuclei for the origin of the third, fourth, 
and fifth cranial nerves. The nucleus for the third and fourth consists of a column 
of cells of large size on either side of, and close to, the median line. The upper 
nucleus of the fifth is situated external to this at the extreme lateral margin of the 
lower part of the gray matter. In addition to these cells there are found at the 
periphery of the zone of gray matter surrounding the aqueduct some other and 
larger cells, sometimes single, sometimes grouped in twos or threes, or even more. 
They are globular and lie in the midst of well-marked nerve-fibres, with which 
their processes appear to be continuous. 
The white matter of the cerebrum consists of medullated fibres varying in 
size and arranged in bundles, separated by neuroglia. They may be divided into 
three distinct systems, according to the course which they take : (1) diverging or 
peduncular fibres, which connect the hemispheres with the medulla oblongata and 
cord ; (2) transverse commissural fibres, which connect together the two hemispheres ; 
(3) commissural fibres, which connect different structures in the same hemisphere. 
1. The diverging- oi' peduncular fibres consist of a main body which origi- 
nates in the cord and medulla oblongata, form the longitudinal fibres of the pons, 
and, dividing into two main branches diverging from each other, constitute the 
crura cerebri or cerebral peduncles, and ascend into the optic thalami and corpora 
striata, and, emerging from these bodies, form the corona radiata and radiate into 
the convolutions of the hemispheres. As they pass through the optic thalami and 
corpora striata many of the fibres terminate in the gray matter of these ganglia. INTERIOR OF THE CEREBRUM. 
707 
and other fibres arise from them in greater number than those which terminate in 
them, so that more fibres pass out of the ganglia than pass into them. But, in 
addition to these, others of the peduncular fibres pass uninterruptedly through the 
ganglia from the cerebral peduncles to the corona radiata. In the crura cerebri, as 
has been before described, the diverging fibres derived from the longitudinal fibres 
of the pons Varolii are arranged in two strata, which are separated by the locus 
niger, the anterior or superficial stratum forming the crusta of these bodies, and 
the posterior or deeper stratum the tegmentum. The fibres derived from these two 
sources take a different course, and will have to be separately considered. 
The fibres of the crusta are derived from the anterior pyramid of the medulla 
(see Figs. 444 and 445, pp. 670 and 671), which fibres are continued upward through 
the pons to form the crusta; they are reinforced in their passage through the crus 
by accessory fibres derived from the central gray matter around the Sylvian aqueduct 
and from the locus niger. When they emerge from the crus some of the fibres pass 
to the internal capsule, between the caudate and lenticular nuclei, where they give off 
branches to these ganglia and receive others from them, and then, issuing from the 
capsule, they diverge to form a part of the corona radiata, passing to the cerebral 
cortex. Others of the fibres pass directly upward as radiating fibres to the gray 
matter of the cerebral hemispheres. 
The fibres of the tegmentum are continuous with those longitudinal fibres of the 
pons which are derived from the formatio reticularis of the medulla, which is formed 
by fibres from the olivary body, lateral and posterior columns of the cord, and the 
superior peduncle of the cerebellum. They are reinforced by fibres from the cor- 
pora quadrigemina and corpora geniculata, and enter the optic thalamus, in which 
many terminate and from which others arise; others pass through the body, and, 
with those fibres arising in it, spread out to form the corona radiata, especially join- 
ing the ganglion-cells of the cortex of the temporo-sphenoidal and occipital lobes. 
2. The transverse commissural fibres connect together the two hemispheres. 
They include (a) the transverse fibres of the corpus callosum; (6) the anterior com- 
missure ; (<?) the posterior commissure. 
The corpus callosum, which has already been described, connects together the 
two hemispheres of the brain, penetrating into the substance of the convolutions, 
and intersecting the fibres of the corona radiata in the anterior, middle, and part 
of the posterior lobes. 
The anterior commissure is a round bundle of white fibres which appears to con- 
nect the two corpora striata in the third ventricle. The fibres can, however, be 
traced through this body, and are then seen to curve backward and outward and 
spread out in the medullary substance of the temporo-sphenoidal lobe. 
The posterior commissure passes into the optic thalamus on either side. It con- 
sists of decussating fibres which come from the tegmentum of the crus on one side, 
and pass through the optic thalamus, across the third ventricle, to the white sub- 
stance of the temporo-sphenoidal lobe of the other. Some of the fibres may also 
serve as commissural fibres between the two optic thalami. 
3. Commissural Fibres connecting- Different Structures in the Same 
Hemisphere.-These fibres are of two kinds: (1) those which connect adjacent 
convolutions, and which are termed arcuate or association fibres ; (2) those which 
connect more distant parts in the same hemisphere-the longitudinal or collateral 
fibres. 
The arcuate or association fibres are situated immediately beneath the gray 
substance of the cortex of the hemispheres, and connect together adjacent con- 
volutions. 
The longitudinal or collateral fibres include the following: (a) the fornix ; (6) 
the longitudinal fibres of the corpus callosum ; (c) the taenia semicircularis; (d) the 
uncinate fasciculus; (c) the fillet of the gyrus fornicatus; (/) the inferior longi- 
tudinal fasciculus. 
(u) The fornix connects the optic thalamus with the hippocampus major and 
uncinate convolution. It has already been described as arising from the gray mat- 708 
THE NERVOUS SYSTEM. 
ter of the optic thalamus: it then emerges from the under surface of this body, 
forms the corpus albicans, where the fibres are arranged in loops, between which 
nerve-cells are to be found; it then passes upward into the third ventricle, and 
joins with the fibres of the other side, forming the body of the fornix ; from this 
the posterior pillars diverge, and, entering the middle cornu of the lateral ventricle, 
part of its fibres are distributed to the hippocampus major, and the remainder end 
as the taenia hippocampi or fimbria, which is continued as a distinct piece to the 
crochet or uncus of the uncinate convolution. 
(6) The longitudinal fibres of the corpus callosum, or nerves of Lancisi, connect 
the anterior and posterior extremities of the gyrus fornicatus or convolution of the 
corpus callosum. 
(c) The tcenia semicircular is, situated between the corpus striatum and optic 
thalamus in the lateral ventricle, is connected in front with the anterior pillar of 
the fornix, and behind with a nucleus of gray matter (nucleus amygdala?) situated 
at the apex of the temporo-sphenoidal lobe and projecting into the termination of 
the middle horn of the lateral ventricle. 
(dfi The uncinate fasciculus connects the convolutions of the frontal and tem- 
poro-sphenoidal lobes. It passes across the bottom of the Sylvian fissure and 
traverses the claustrum. 
(e) The fillet of the gyrus fornicatus is a band of white matter which encircles 
the hemisphere in an antero-posterior direction, lying in the substance of the con- 
volution of the corpus callosum. Commencing in front at the anterior perforated 
space, it passes forward and upward parallel with the rostrum, winds round the 
genu, runs in the convolution from before backward immediately above the corpus 
callosum, turns round its posterior extremity, and is continued downward and for- 
ward in the temporo-sphenoidal lobe to again reach the perforated space. In its 
course it is connected with the secondary convolutions of the gyrus fornicatus by 
short arcuate fibres. 
(/) The inferior longitudinal fasciculus is a collection of fibres which connects 
the temporo-sphenoidal and occipital lobes, running along the outer wall of the 
middle and posterior cornu. 
[For the Blood-vessels of the Brain, see p. 534.] 
The Cerebellum. 
The Cerebellum, or little brain, is that portion of the encephalon which is con- 
tained in the inferior occipital fossae. It is situated beneath the posterior lobes of 
the cerebrum, from which it is separated by the tentorium. Its average weight in 
the male is 5 oz. 4 dr. It attains its maximum weight between the twenty-fifth 
and fortieth years, its increase in weight after the fourteenth year being relatively 
greater in the female than in the male. The proportion between the cerebellum 
and cerebrum is, in the male, as 1 to and in the female as 1 to In the 
infant the cerebellum is proportionately much smaller than in the adult, the rela- 
tion between it and the cerebrum being, according to Chaussier, between 1 to 13 
and 1 to 26 ; by Cruveilhier the proportion was found to be 1 to 20. In form the 
cerebellum is oblong and flattened from above downward, its great diameter being 
from side to side. It measures from three and a half to four inches transversely 
and from two to two and a half inches from before backward, being about two 
inches thick in the centre and about six lines at the circumference, which is the 
thinnest part. It consists of gray and white matter : the former, darker than that 
of the cerebrum, occupies the surface; the latter, the interior. The surface of the 
cerebellum is not convoluted like the cerebrum, but traversed by numerous curved 
furrows or sulci, which vary in depth at different parts and separate the laminae of 
which its exterior is composed. 
Its upper surface (Fig. 478) is somewhat elevated in the median line and 
depressed toward its circumference; it consists of two lateral hemispheres con- 
nected together by an elevated median portion or lobe, the superior vermiform pro- THE CEREBELLUM. 
709 
cess. The median lobe is the fundamental part, and in some animals, as fishes and 
reptiles, the only part which exists, the hemispheres being additions and attaining 
their maximum size in man. The hemispheres are separated in front by a deep 
notch, the incisura cerebelli anterior, which encircles the corpora quadrigemina 
behind; they are also separated by a similar notch behind, the incisura cerebelli 
Fig. 478. 
Lolnlns 
centralis 
Jncisura 
. anterior 
ifontirtrliis 
cerebelli 
Commit* 
sura sim* 
jilevc 
Jncisara. 
cereie/tijaoslerior' 
Upper Surface of the Cerebellum. 
posterior, in which is received the upper part of the falx cerebelli. The superior 
vermiform process (upper part of the median lobe of the cerebellum) extends from 
the notch on the anterior to that on the posterior border. It is divided into three 
lobes: the lobulus centralis, a small lobe, situated in the incisura anterior; the 
monticulus cerebelli, the central projecting part of the process; and the commis- 
sura simplex, a small lobe near the incisura posterior. 
Fig. 479. 
Under Surface of the Cerebellum. 
The under surface of the cerebellum (Fig- 479) is subdivided into two lateral 
hemispheres by a depression, the valley, which extends from before backward in 
the middle line. The lateral hemispheres are lodged in the inferior occipital fossae; 
the median depression or valley receives the back part of the medulla oblongata, is 
broader in the centre than at either extremity, and has projecting from its floor 710 
THE NERVOUS SYSTEM. 
part of the median lobe of the cerebellum, called the inferior vermiform process. 
The parts entering into the composition of this body are, from behind forward, the 
commissura brevis, situated in the incisura posterior; in front of this, a laminated 
conical projection, the pyramid; more anteriorly, a larger eminence, the uvula, 
which is placed between the two rounded lobes, the amygdalce or tonsils, which 
occupy the sides of the valley. The uvula is connected with the amygdalae by a 
commissure of gray matter indented on the surface, called the furrowed band. In 
front of the uvula is the nodule ; it is the anterior pointed termination of the infe- 
rior vermiform process, and projects into the cavity of the fourth ventricle; it has 
been named by Malacarne the laminated tubercle. On each side of the nodule is a 
thin layer of white substance attached externally to the flocculus and internally to 
the nodule; these form together the posterior medullary velum or commissure of the 
flocculus. It is usually covered in and concealed by the amygdalae, and cannot be 
seen until they are drawn aside. This band is of a semilunar form on each side, its 
anterior margin being free and concave, its posterior attached just in front of the 
furrowed band. Between it and the nodule and the uvula behind is a deep fossa 
called the swallow's nest (nidus hirundinis). 
Lobes of the Cerebellum.-Each hemisphere is divided into an upper and a 
lower portion by the great horizontal fissure, which commences in front at the pons 
and passes horizontally round the free margin of either hemisphere backward to the 
middle line. From this primary fissure numerous secondary fissures proceed which 
separate the cerebellum into lobes. 
Upon the upper surface of either hemisphere there are two lobes, separated from 
each other by a fissure. These are the anterior or square lobe, which extends as 
far back as the posterior edge of the vermiform process, and the posterior or semi- 
lunar lobe, which passes from the termination of the preceding to the great hori- 
zontal fissure. 
Upon the under surface of either hemisphere there are five lobes, separated by 
sulci; these are, from before backward-1, the flocculus or subpeduncular lobe, a 
prominent tuft situated behind and below the middle peduncle of the cerebellum; 
its surface is composed of gray matter subdivided into a fewT small laminae: it is 
sometimes called the pneumogastric lobule, from being situated behind the pneumo- 
gastric nerve; 2, the amygdala or tonsil, situated on either side of the great median 
fissure or valley and projecting into the fourth ventricle; 3, the digastric lobe, 
situated on the outside of the 
tonsil and connected in part 
with the pyramid; 4, the slen- 
der lobe, behind the digastric, 
and connected with the back 
part of the pyramid and the 
commissura brevis; and, more 
posteriorly, 5, the inferior pos- 
terior lobe, which also joins 
the commissura brevis in the 
valley. 
Internal Structure of the 
Cerebellum. - The cerebel- 
lum consists of both white and 
gray matter. 
If a vertical section (Fig. 
480) is made through either 
hemisphere of the cerebellum 
midway between its centre and 
the superior vermiform process, 
the interior will be found to consist of a central stem of white matter which contains 
in its interior a gray mass, the corpus dentatum. From the surface of this central 
stem a series of plates of medullary matter are detached, which, covered with gray 
Fig. 480. 
Vertical Section of the Cerebellum. THE CEREBELLUM. 
711 
matter, form the laminae, and from the anterior part of each hemisphere arise three 
large processes or peduncles-superior, middle, and inferior-by which the cerebel- 
lum is connected with the rest of the encephalon. 
The white matter includes two varieties of nerve-matter: (1) the peduncular 
fibres which are directly continuous with the fibres of the peduncles of the cere- 
bellum ; (2) the fibres (fibrce proprice) proper to the cerebellum itself. 
The peduncles of the cerebellum-superior, middle, and posterior-serve to con- 
nect it with the rest of the encephalon. 
The superior peduncles (processus e cerebello ad testes) arise from the middle of 
the white matter of the cerebral hemispheres; they run beneath the testes of the 
corpora quadrigemina, and, emerging at its posterior border, pass outward and back- 
ward to the cerebellum. Each peduncle forms the upper part of the lateral bound- 
ary of the fourth ventricle, and is connected with its fellow of the opposite side by 
the valve of Vieussens. Beneath the corpora quadrigemina the innermost fibres of 
each peduncle decussate with each other, so that some fibres from the one half of the 
cerebrum are continued into the other half of the cerebellum. Upon entering the 
cerebellum the fibres of this peduncle pass to a great extent into the interior of the 
corpus dentatum, though some wind round it and reach the gray cortical matter, 
especially on its inferior surface. 
The middle peduncles (processus ad pontem), the largest of the three, connect 
together the two hemispheres of the cerebellum, forming their great transverse 
commissure. They consist of a mass of curved fibres which arise in the gray mat- 
ter of the foliated cortex of the hemispheres of the cerebellum and pass across the 
pons Varolii, forming its tranverse fibres, to the same point on the opposite side. 
The inferior peduncles (processus ad medullamj connect the cerebellum with 
the medulla oblongata. As the restiform bodies they pass upward and outward, 
forming part of the lateral wall of the fourth ventricle; entering the cerebellum, 
they end in the gray cortex of the upper surface of this organ. 
The fibres proprioe of the cerebellum are of two kinds: (1) commissural fibres, 
which cross the middle line to connect the opposite halves of the hemispheres, some 
at the anterior part and others at the posterior part of the vermiform process; (2) 
arcuate or association fibres, which connect one lamina with another, arching across 
the fissures between the laminae. 
The gray matter of the cerebellum is found in two situations: (1) on the sur- 
face, forming the cortex ; (2) as independent masses in the interior. 
The gray matter of the cortex presents a characteristic foliated appearance, 
from its arrangement in a series of laminae, due to the division of the central white 
substance into a series of plates which divide and subdivide and are capped with 
gray matter. This arrangement gives to the cut surface of the organ a foli- 
ated appearance, to which the name arbor vitae has been applied (Fig. 480). This 
cortex presents a remarkable structure consisting of two distinct layers-viz. an 
external gray or cellular layer, and an internal rust-colored granular layer. Between 
the two, or rather situated in the deepest part of the gray or cellular layer, is an 
incomplete stratum of the characteristic cells of the cerebellum, the corpuscles of 
Purkinje. Externally, the cortex is covered by pia mater, and internally is the 
medullary centre, consisting mainly of nerve-fibres. 
The external gray or cellular layer (Fig. 481, a) consists of a transparent tissue, 
like neuroglia, containing fibres and cells. The fibres are delicate fibrillae running 
at right angles to the surface, and many of them connected with the processes of 
the large nerve-cells immediately below; others are delicate supporting connective- 
tissue-like fibres, which spread out into a broad base against the inner surface of the 
pia mater. 
The cells are granule-like bodies, some very small and probably belonging to 
the neuroglia; others, according to Lockhart Clarke, connected with the processes 
of the corpuscles of Purkinje, which lie immediately beneath. 
The corpuscles of Purkinje (Fig. 481, 6) are flask-shaped cells resting in the 
external layer against the rust-colored internal layer. From their under surface a 712 
THE NERVOUS SYSTEM. 
single slender process arises, which passes through the inner layer and becomes 
continuous with the axial cylinder of a medullated nerve-fibre in the medullary 
substance beneath. From the other extremity two peripheral processes are given 
off', which branch in an antler-like manner in the external layer, some of the finer 
processes becoming connected with the cells in this layer. 
The inner or rust-colored layer (Fig. 
481, c) is characterized by containing 
multitudes of granular-looking bodies 
imbedded in a gelatinous matrix. They 
are minute stellate cells consisting of a 
well-defined nucleus with a thin proto- 
plasmic envelope. Between the cells is 
a fine nerve-network, with which the 
processes of the cells are supposed to be 
continuous. 
2. The independent centres of gray 
matter in the cerebellum are-(1) the 
corpus dentatum, (2) the roof-nuclei of 
Stilling. 
The corpus dentatum or ganglion 
of the cerebellum is situated a little to 
the inner side of the centre of the stem 
of white matter. It consists of an open 
bag or capsule of gray matter, the section 
of which presents a gray dentated outline, 
Fig. 481. 
Vertical Section through the Gray Matter of the Human Cerebellum (magnified about 100 diameters-Klein 
and Noble Smith): a, the external gray or cellular layer; b, corpuscles of Purkinje; c. internal rust-colored 
granular layer; d, white substance. Two branched capillaries are seen at the upper part passing into the gray 
matter from the j>ia mater. The nerve-network has been omitted in the larger figure for the sake of clear- 
ness. It is seen in B, which shows one of the ganglion-cells of Purkinje with its dichotomously branched 
processes, and a portion of the adjoining granular and cellular layers. Nearer the surface the meshes of the 
nerve-network become more elongated, as if they were stretched out in a direction vertical to the surface. 
At the surface, however, they are like those here represented, but smaller. 
open at its anterior part. It is surrounded by white fibres; white fibres are also 
contained in its interior, which issue from it to join the superior peduncles. The 
roof-nuclei of Stilling are two small gray masses situated at the anterior end of 
the superior vermiform process and projecting into the valve of Vieussens, so as to 
assist in the formation of the roof of the fourth ventricle. 
Fourth Ventricle (Fig. 441, p. 666, and Figs. 475 and 476, pp. 700 and 701). 
The fourth ventricle, or ventricle of the cerebellum, is the space between 
the posterior surface of the medulla oblongata and pons in front and the cerebellum FOURTH VENTRICLE. 
713 
behind. It is lozenge- or diamond-shaped; that is to say, it is composed of two 
triangles, with their bases opposed to each other. The lower triangle appears to 
be formed by the divergence of the posterior pyramids or funiculi graciles and 
the restiform bodies of the medulla oblongata on either side. These columns pass 
upward and outward at an acute angle to the lateral hemispheres of the cerebellum, 
leaving by their divergence a triangular space which forms the lower half of the 
fourth ventricle. In like manner, the upper triangle appears to be formed by the 
divergence of the superior peduncles (processus e cerebello ad testes) of the cerebel- 
lum. These crura as they emerge from the corpora quadrigemina are in contact by 
their lateral margins, but they gradually diverge, passing downward, backward, and 
outward, to reach the cerebellum, thus enclosing a triangular space wdiich forms the 
upper half of the fourth ventricle. This cavity is therefore bounded laterally by 
the processus e cerebello ad testes above, and by the diverging restiform bodies and 
posterior pyramids below. 
It presents four angles. The upper angle reaches as high as the upper border 
of the pons; it presents the lower opening of the aqueduct of Sylvius, by which 
this ventricle communicates with the third ventricle. The lower angle is on a level 
with the lower border of the olivary body, and presents a minute opening, the aper- 
ture of the central canal of the spinal cord. At its lateral angles the fourth ven- 
tricle is extended for a short distance between the side of the medulla and the cere- 
bellum, where these two structures come in contact. 
The roof is arched and is formed in the upper triangle by the valve of Vieussens 
-a lamina of white matter streaked with gray which bridges across from one supe- 
rior peduncle to the other. The roof of the lower half is formed by a reflection of 
pia mater passing from the under surface of the inferior vermiform process of the 
cerebellum to the spinal cord. Above this is the inferior vermiform process itself. 
This pia-matral covering is lined on its under or ventricular surface by a layer of 
epithelium which is continuous with that lining the sides and base of the cavity, 
and is perforated by a hole, the foramen of Majendie, by which the cavity of the 
ventricle communicates with the subarachnoidean space. 
The floor is formed by the posterior surface of the medulla oblongata and pons. 
In the median line is seen a fissure which gradually becomes obliterated above and 
terminates below at the lower angle of the ventricle. From the resemblance that 
there is in the diverging lower boundaries of the space and the central fissure to 
the nib of a writing-pen, the lower triangle has been named the calamus scriptorius. 
On each side of the median fissure are two spindle-shaped longitudinal eminences, 
the fasciculi teretes ; they extend the entire length of the floor, being indistinct 
below and of a grayish color, but well marked and whiter above. Each eminence 
consists of fibres derived from the lateral tract, restiform body, and posterior pyr- 
amid, which ascend to the cerebrum. External to this eminence there is a slight 
groove which terminates below in a little fossa, called the fovea posterior, and in 
the same groove, opposite the widest part of the ventricle, there is a second depres- 
sion or fossa, called the fovea anterior. Above the anterior fossa and external to 
the fasciculi teretes is a small eminence of dark gray substance which presents a 
bluish tint through the thin stratum covering it; this is called the locus cceruleus ; 
and a thin streak of the same color, continued up from this on either side of the 
fasciculi teretes as far as the top of the ventricle, is called the tcenia violacea. The 
lower part of the floor of the ventricle is crossed by several white transverse lines, 
linece transversce; they emerge from the posterior median fissure; some enter the 
crus cerebelli, others enter the roots of origin of the auditory nerve, whilst some 
pass upward and outward on the floor of the ventricle. 
In addition to the objects above mentioned there are to be seen on the floor of 
the fourth ventricle several little elevations or eminences which correspond to the 
nuclei of origin of some of the cranial nerves, which, as before mentioned, arise 
from special collections of ganglion-cells in the gray matter of the floor of this cav- 
ity. One of these eminences is to be seen on either side of the middle line, close 
to the inferior angle of the space; this marks the nucleus of origin of the hypo- 714 
THE NERVOUS SYSTEM. 
glossal and spinal accessory nerve. In front and external to this, and just behind 
the fovea posterior, is a second eminence, which marks the nuclei of the pneumo- 
gastric and glosso-pharyngeal nerves, the lower part of the elevation corresponding 
to the roots of origin of the pneumogastric; the upper part to that of the glosso- 
pharyngeal. In front of the fovea posterior and in a line with the preceding 
elevation is a third, which marks the position of the nucleus of the auditory 
nerve. Finally, in the upper part of the space close behind the fovea anterior is 
a rounded elevation which denotes the common nucleus of the abducent and facial 
nerves. 
The lining membrane of the fourth ventricle is continuous with that of the 
third through the aqueduct of Sylvius, and its cavity communicates below with 
the subarachnoid space Of the brain and cord through an aperture in the layer of 
pia mater extending between the cerebellum and medulla oblongata. Laterally, 
this membrane is reflected outward a short distance between the cerebellum and 
medulla. 
The choroid plexuses of the fourth ventricle are two in number: they are 
delicate vascular fringes which project into the ventricle on each side, passing 
from the point of the inferior vermiform process to the outer margin of the resti- 
form bodies. 
The gray matter in the floor of the ventricle consists of a tolerably thick 
stratum continuous below with the gray commissure of the cord, and extending 
up as high as the aqueduct of Sylvius, and, in addition, of some special deposits 
connected with the roots of origin of certain nerves which have already been 
referred to. Cranial Nerves. 
THE Cranial Nerves arise from some part of the cerebro-spinal centre, and are 
transmitted through foramina in the base of the cranium. They have been 
named by Willis numerically, according to the order in which they pass out of the 
base of the brain. Other names are also given to them, derived from the parts to 
which they are distributed or from their functions. Taken in their order, from 
before backward, they are as follows: 
1st, Olfactory. 
2d, Optic. 
3d, Motor oculi. 
4th, Pathetic. 
5th, Trifacial (Trigeminus). 
6th, Abducens. 
7th, 
Facial (Portio dura). 
Auditory (Portio mollis). 
8th, 
Glosso-phary ngeal. 
Pneumogastric (Par vagum). 
Spinal Accessory. 
9th, 
Hypoglossal. 
It will be seen, however, that this arrangement is somewhat defective; that, in fact, 
two entirely separate and distinct nerves, the facial and auditory, are classed together 
as the seventh pair; and that three nerves, the glosso-pharyngeal, pneumogastric, 
and spinal accessory, are included in the eighth pair. This has induced Sbm- 
merring to alter the numerical arrangement somewhat. He considers the seventh 
pair as consisting of two nerves, which he enumerates as seventh and eighth respect- 
ively, and the eighth pair as consisting of three distinct nerves, which he names the 
ninth, tenth, and eleventh, while the last, or ninth nerve of Willis, he calls the 
twelfth cranial nerve. 
The following table will show the respective arrangements: 
Olfactory, 
Sommerring. 
First pair. 
Willis. 
First 
pair. 
Optic, 
Motor oculi, 
Second 
u 
Second 
(,C 
Third 
U 
Third 
cc 
Pathetic, 
Fourth 
64 
F ourth 
cc 
Trifacial, 
Fifth 
U 
Fifth 
cc 
Abducens, 
Sixth 
U 
Sixth 
a 
Facial (Portio dura), 
Seventh 
U 
Seventh 
cc 
Auditory (Portio mollis), 
Eighth 
U 
Glosso-pharyngeal, 
Ninth 
CC 
Pneumogastric, 
Spinal Accessory, 
Tenth 
Eleventh 
u 
cc 
Eighth 
a 
Hypoglossal, 
Twelfth 
u 
Ninth 
u 
There can be no doubt that the arrangement of Sbmmerring is the better of the 
two, and it is gradually being adopted by anatomical writers of the present day. It 
has been thought better, therefore, to alter the plan that has hitherto been adopted 
in this work, and to adopt the nomenclature of Sbmmerring. [The little branch 
of the hypoglossal nerve descending on the sheath of the carotid artery, however, 
still retains its old name, the ramus descendens noni (descending branch of the 
ninth), though really a branch of the twelfth nerve.] 
The cranial nerves may be subdivided into four groups, according to the pecu- 
liar function possessed by each-viz. nerves of special sense, nerves of common 
715 716 
CRANIAL NERVES. 
sensation, nerves of motion, and mixed nerves. These groups may be thus 
arranged: 
Nerves of Special Sense. 
Olfactory. 
Optic. 
Auditory. 
Part of glosso-pharyngeal. 
Lingual or gustatory branch of fifth. 
Nerves of Motion. 
Motor oculi. 
Pathetic. 
Part of third division of fifth. 
Abducens. 
Facial. 
Hypoglossal. 
Nerves of Common Sensation. 
Fifth (greater portion). 
Part of glosso-pharyngeal. 
Mixed Nerves. 
Pneumogastric. 
Spinal accessory. 
All the cranial nerves are connected to some part of the surface of the brain. 
This is termed their superficial or apparent origin. But their fibres may, in all 
cases, be traced deeply into the substance of the organ. This part is called their 
deep or real origin.1 
First Nerve (Fig. 466, p. 688) 
The first or Olfactory Nerve, the special nerve of the sense of smell, is in 
reality a slender process of brain-substance extending forward on the under surface 
of the frontal lobe and terminating in a bulbous extremity, from which the olfac- 
tory nerves are given off. The process arises by three roots. 
The external, or long, root is a narrow, white, medullary band which passes out- 
ward across the fissure of Sylvius into the substance of the island of Reil. Its 
deep origin has been traced to the nucleus of gray matter in the temporo-sphenoidal 
lobe in front of the pes hippocampi. 
The middle, or gray, root arises from a papilla of gray matter {caruncula mam- 
millaris) imbedded in the anterior lobe. It contains white fibres in its interior 
which are connected with the corpus striatum. 
The internal, or short, root is composed of white fibres which arise from the 
inner and back part of the anterior lobe, being connected, according to Foville, 
with the longitudinal fibres of the gyrus fornicatus. 
These three roots unite and form a flat band, narrower in the middle than at 
either extremity, and of a somewhat prismoid form on section. It is soft in texture, 
and contains a considerable amount of gray matter in its substance. As it passes 
forward it is contained in a deep sulcus between two convolutions lying on the 
under surface of the anterior lobe, on either side of the longitudinal fissure, and is 
retained in position by the arachnoid membrane which covers it. On reaching the 
cribriform plate of the ethmoid bone it expands into an oblong mass of gray brain- 
substance, the olfactory bulb. From the under part of this bulb are given off 
numerous filaments, about twenty in number, which pass through the cribriform 
foramina and are distributed to the mucous membrane of the nose. Each filament 
is surrounded by a tubular prolongation from the dura mater and pia mater, the 
former being lost on the periosteum lining the nose ; the latter, in the neurilemma 
of the nerve. The filaments, as they enter the nares, are divisible into three 
groups: an inner group, larger than those on the outer wall, spread out over the 
upper third of the septum ; a middle set, confined to the roof of the nose; and an 
1 The deep origin, or point of connection, of the cranial nerves with the brain is still, in some 
instances, a matter of uncertainty. It seems probable that each of them arises from some special 
centre of gray matter, termed a nucleus: at all events, many of them can be traced to such special 
nuclei, through which, no doubt, they are connected with other portions of the cerebral mass. It 
has been thought advisable in the text to give only the most modern views as to the deep origin of 
these nerves, without burdening the student's mind with all the different opinions of anatomists 
which have at various times been set forth in regard to the place from which these nerves take their 
origin. For these recent views the Editor, as stated in a former edition, is indebted to the late Dr. 
Lockhart Clarke. SECOND NERVE. 
717 
outer set, which are distributed over the superior and middle turbinated bones and 
the surface of the ethmoid in front of them. As the filaments descend they unite 
in a plexiform network, and are believed by most observers to terminate in the cells 
of Schultze. 
The olfactory differs in structure from other nerves in containing gray matter in 
its interior and being soft and pulpy in consistence. Its filaments are deficient in 
the white substance of Schwann, and consist of axis-cylinders with a distinct nucleated 
sheath, in which there are, however, fewer nuclei than in ordinary non-medullated 
fibres. 
Second Nerve. 
The second or Optic Nerve, the special nerve of the sense of sight, is distrib- 
uted exclusively to the eyeball. The nerves of opposite sides are connected together 
at the commissure, and from the back of the 
commissure they may be traced to the brain 
under the name of the optic tracts. 
The optic tract at its connection with the 
brain is divided into two bands. One of these 
arises from the stratum opticum of the corpora 
quadrigemina, emerges from this body as the 
anterior brachium, and passes between the inner 
and outer geniculate bodies; the other arises 
from the optic thalamus and passes through the 
inner geniculate body, from which it derives 
fibres, and joins with the other band to form 
the tract. From this origin the tract winds 
obliquelv across the under surface of the crus 
cerebri in the form of a flattened band destitute 
of neurilemma, and is attached to the crus by 
its anterior margin. It then assumes a cylin- 
drical form, and as it passes forward is connected 
with the tuber cinereum and lamina cinerea, 
from both of which it receives fibres. It finally 
joins with the tract of the opposite side to form the optic commissure. 
The commissure or chiasma, somewhat quadrilateral in form, rests upon the optic 
groove of the sphenoid bone, being bounded above by the lamina cinerea, behind by 
the tuber cinereum, on either side by the anterior perfo- 
rated space. Within the commissure the optic nerves of 
the two sides undergo a partial decussation. The fibres 
which form the inner margin of each tract are continued 
across from one to the other side of the brain, and have 
no connection with the optic nerves. These may be 
regarded as commissural fibres (intercerebraT) between 
the thalami of opposite sides. Some fibres are continued 
across the anterior border of the chiasma, and connect 
the optic nerves of the two sides, having no relation with the optic tracts.1 They 
may be regarded as commissural fibres between the two retinae (interretinal fibres). 
The outer fibres of each tract are continued into the optic nerve of the same side. 
The central fibres of each tract are continued into the optic nerve of the opposite 
side, decussating in the commissure with similar fibres of the opposite tract.2 
The optic nerves arise from the fore part of the commissure, and, diverging from 
one another, become rounded in form and firm in texture, and are enclosed in a 
sheath derived from the arachnoid. As each nerve passes through the correspond- 
Fig. 482. 
Globe of 
The Optic Nerves and Optic Tracts. 
Fig. 483. 
To OPTIC N. 
-ofscime side 
-of opposite side 
Course of the Fibres in the Optic 
Commissure. 
1 The presence of these fibres has been doubted by some observers, but they have been recently 
asserted to exist by Stilling. . # . 
2 A specimen of congenital absence of the optic commissure is to be found in the museum of the 
Westminster Hospital. 718 
CRANIAL NERVES. 
ing optic foramen it receives a sheath from the dura mater, and as it enters the orbit 
this sheath subdivides into two layers, one of which becomes continuous with the 
periosteum of the orbit; the other forms a sheath for the nerve and surrounds it as 
far as the sclerotic. The nerve passes through the cavity of the orbit, pierces the 
sclerotic and choroid coats at the back part of the eyeball a little to the nasal side 
of its centre, and expands into the retina. Arnold describes a communication 
between the optic nerve in the orbit and the ascending branches of Meckel's 
ganglion. A small artery, the arteria centralis retince, perforates the optic nerve 
a little behind the globe, and runs along its interior in a tubular canal of fibrous 
tissue. It supplies the inner surface of the retina and is accompanied by corre- 
sponding veins. [For the exact connection between the optic nerve and the retina 
see the description of the Eye.] 
Third Nerve (Figs. 484, 485). 
The third or Motor oculi Nerve supplies all the muscles of the orbit except 
the Superior oblique and External rectus; it also sends motor filaments to the iris 
and the ciliary muscle. It is a 
rather large nerve, of rounded 
form and firm texture, having its 
apparent origin from the inner 
surface of the crus cerebri imme- 
diately in front of the pons Varolii. 
The deep origin may be traced 
through the locus niger and teg- 
mentum of the crus to a nucleus 
situated on either side of the me- 
dian line in the floor of the aque- 
duct of Sylvius, beneath the cor- 
pora quadrigemina. On emerging 
from the brain the nerve is invested 
with a sheath of pia mater and en- 
closed in a prolongation from the 
arachnoid. It then pierces the dura 
mater below and external to the 
posterior clinoid process, passing 
between the two processes from the 
free and attached borders of the 
tentorium, which are prolonged 
forward to be connected with the 
anterior and posterior clinoid pro- 
cesses of the sphenoid bone. It 
passes along the outer wall of the 
cavernous sinus, above the other 
orbital nerves, receiving in its 
course one or two filaments from 
the cavernous plexus of the sym- 
pathetic. It then divides into two 
branches, which enter the orbit 
through the sphenoidal fissure be- 
tween the two heads of the External rectus muscle. On passing through the fissure 
the nerve is placed below the fourth and the frontal and lachrymal branches of the 
ophthalmic nerve, and has, passing between its two divisions, the nasal nerve. 
The superior division, the smaller, passes inward over the optic nerve, and sup- 
plies the Superior rectus and Levator palpebrae. It occasionally communicates with 
the ganglionic branch of the nasal nerve. 
The inferior division, the larger, divides into three branches. One passes beneath 
Fig. 484. 
foy ra.Trochle 
Motor Jtool' I 
Sanscrit Hoot! 
Recurre.nt Fita,me.ni 
to Dura-Mafor 
Nerves of the Orbit, seen from above. FIFTH NERVE. 
719 
the optic nerve to the Internal rectus, another to the Inferior rectus, and the third, 
the largest of the three, passes forward between the Inferior and External recti to 
the Inferior oblique. From the latter a short thick branch is given off to the lower 
part of the lenticular ganglion, which forms its inferior root and gives one or two 
filaments to the Inferior rectus. All these branches enter the muscles on their ocu- 
lar surface. 
The fourth or Pathetic Nerve (trochlear), the smallest of the cranial nerves, 
supplies the Superior oblique muscle. Its apparent origin, at the base of the brain, 
is on the outer side of the crus cerebri, just in front of the pons Varolii, but the 
fibres can be traced backward behind the corpora quadrigemina to the valve of 
Vieussens, on the upper surface of which the two nerves are connected by a trans- 
verse band of fibres, forming a partial decussation. Its deep origin may be traced 
to a nucleus in the floor of the aqueduct of Sylvius immediately below that of the 
third nerve. The nerve winds round the outer side of the crus cerebri immediately 
above the pons Varolii, pierces the dura mater in the free border of the tentorium 
cerebelli near the posterior clinoid process, above the oval opening for the fifth 
nerve, and passes forward through the outer wall of the cavernous sinus between 
the third and the ophthalmic division of the fifth. It crosses the third nerve 
and enters the orbit through the sphenoidal fissure. It now becomes the highest 
of all the nerves, lying at the inner extremity of the fissure internal to the frontal 
nerve. In the orbit it passes inward above the origin of the Levator palpebrse, 
and finally enters the orbital surface of the Superior oblique muscle. 
In the outer wall of the cavernous sinus this nerve receives some filaments 
from the cavernous plexus of the sympathetic. It is not unfrequently blended 
with the ophthalmic division of the fifth, and occasionally gives off a branch to 
assist in the formation of the lachrymal nerve. It also gives off a recurrent 
branch, which passes backward between the layers of the tentorium, dividing 
into two or three filaments which may be traced as far back as the wall of the 
lateral sinus. 
Fourth Nerve (Fig. 484). 
Fifth Nerve. 
The fifth or Trifacial Nerve (trigeminus) is the largest cranial nerve, and 
resembles a spinal nerve in several particulars: it arises by two roots; of these the 
anterior is the smaller and is the motor root, the posterior the larger and sensory. 
Moreover, like the spinal nerves, the posterior or sensory root has a ganglion devel- 
oped upon it. The functions of this nerve are various. It is a nerve of common 
sensation and of motion, and perhaps to a certain extent of special sense. It is 
the great sensitive nerve of the head and face, the motor nerve of the muscles of 
mastication, and its lingual branch is possibly one of the nerves of the special sense 
of taste. It arises by two roots-a posterior larger or sensory, and an anterior 
smaller or motor root. Its superficial origin is from the side of the pons Varolii, 
a little nearer to the upper than the lower border. The smaller root consists of 
three or four bundles; in the larger the bundles are more numerous, varying in 
number from seventv to a hundred; the two roots are separated from one another 
bv a few of the transverse fibres of the pons. The large root of the fifth or tri- 
geminal arises chiefly from the gray tubercle of Rolando or the upper expanded 
extremity of the posterior gray horn of the medulla; the small or motor root arises 
from two masses of larger multipolar cells situated on the inner side and close to 
the gray tubercle, and intimately connected with it. The two roots of the nerve 
pass forward through an oval opening in the dura mater on the superior border of 
the petrous portion of the temporal bone, above the internal auditory meatus: they 
then run between the bone and the dura mater to the apex of the petrous portion 
of the temporal bone, where the fibres of the sensory root form a large semilunar 
ganglion (G asserian), while the motor root passes beneath the ganglion without 720 
CRANIAL NERVES. 
having any connection with it, and outside the cranium joins with one of the trunks 
derived from it. 
The Gasserian or semilunar ganglion1 is lodged in a depression near the apex 
of the petrous portion of the temporal bone. It is of somewhat crescentic form, 
with its convexity turned forward. Its upper surface is intimately adherent to the 
dura mater. Besides the small or motor root the large superficial petrosal nerve 
lies underneath the ganglion. 
Branches.-This ganglion receives on its inner side filaments from the carotid 
plexus of the sympathetic, and from it some minute branches are given off' to the 
Fig. 485. 
Internal Carotid, An 
A Carotid Pleocns. 
Lenticular or 
Ciliary Ganglion 
Upper Division tfirdjL. 
3~ N. 
4&-N. < 
Gc/nsory 
Root 
Moto 7*" 
Root 
omt. 
Lower Division 
(MltalN. 
Nerves of the Orbit and Ophthalmic Ganglion (side view). 
tentorium cerebelli and the dura mater in the middle fossa of the cranium. From 
its anterior border, which is directed forward and outward, three large branches 
proceed-the ophthalmic, superior maxillary, and inferior maxillary. The oph- 
thalmic and superior maxillary consist exclusively of fibres derived from the larger 
root and ganglion, and are solely nerves of common sensation. The third division, 
or inferior maxillary, is composed of fibres from both roots. This, therefore, 
strictly speaking, is the only portion of the fifth nerve which can be said to 
resemble a spinal nerve. 
Ophthalmic Nerve (Figs. 484, 485). 
The Ophthalmic, or first division of the fifth, is a sensory nerve. It supplies 
the eyeball, the lachrymal gland, the mucous lining of the eye and nasal fossae, and 
the integument and muscles of the eyebrow, forehead, and nose. It is the smallest 
of the three divisions of the fifth, arising from the upper part of the Gasserian 
ganglion. It is a short, flattened band about an inch in length, which passes for- 
ward along the outer wall of the cavernous sinus below the other nerves, and just 
before entering the orbit through the sphenoidal fissure divides into three branches, 
lachrymal, frontal, and nasal. The ophthalmic nerve is joined by filaments from 
the cavernous plexus of the sympathetic, communicates with the third and sixth 
1 I am indebted to my friend Mr. J. McCarthy for the following note: "A Viennese anatomist, 
Raimund Balthasar Hirsch (1765), was the first who recognized the ganglionic nature of the swell- 
ing on the sensory root of the fifth nerve, and called it, in honor of his otherwise unknown teacher, 
Jon. Laur. Gasser, the 'ganglion Gasseri.' Julius Casserius, whose name is given to the musculo- 
cutaneous nerve of the arm, was professor at Padua, 1545-1605." (See Hyrth, Lehrbuch der Anatomic, 
n. 895 and p. 55.) OPHTHALMIC NERVE. 
721 
nerve, and is not unfrequently joined with the fourth, and gives off recurrent fila- 
ments which pass between the layers of the tentorium along with a branch from 
the fourth nerve. 
Its branches are the 
The Lachrymal is the smallest of the three branches of the ophthalmic. Not 
unfrequently it arises by two filaments, one from the ophthalmic, the other from the 
fourth ; and this Swan considers to be its usual condition. It passes forward in a 
separate tube of dura mater, and enters the orbit through the narrowest part of the 
sphenoidal fissure. In the orbit it runs along the upper border of the External 
rectus muscle with the lachrymal artery, and sends off a recurrent branch which 
joins the orbital branch of the superior maxillary nerve and occasionally takes the 
place of the temporal branch of this nerve, which is then absent. Within the lach- 
rymal gland it gives off several filaments, which supply the gland and the conjunc- 
tiva. Finally, it pierces the palpebral ligaments, and terminates in the integument 
of the upper eyelid, joining with filaments of the facial nerve. 
The Frontal is the largest division of the ophthalmic, and may be regarded, 
both from its size and direction, as the continuation of the nerve. It enters the 
orbit above the muscles, through the highest and broadest part of the sphenoidal 
fissure, and runs forward along the middle line between the Levator palpebraa and 
the periosteum. Midway between the apex and the base of the orbit it divides into 
two branches, supratrochlear and supraorbital. 
The supratrochlear branch, the smaller of the twm, passes inward above the pul- 
ley of the Superior oblique muscle, and gives off a descending filament which joins 
with the infratrochlear branch of the nasal nerve. It then escapes from the orbit 
between the pulley of the Superior oblique and the supraorbital foramen, curves up 
on to the forehead close to the bone, and ascends beneath the Corrugator supercilii 
and Occipito-frontalis muscles, to both of which it is distributed;1 finally, it is lost 
in the integument of the forehead. 
The supraorbital branch passes forward through the supraorbital foramen, and 
gives off in this situation palpebral filaments to the upper eyelid. It then ascends 
upon the forehead, and terminates in muscular, cutaneous, and pericranial branches. 
The muscular branches supply the Corrugator supercilii, Occipito-frontalis, and Orbic- 
ularis palpebrarum, furnishing these muscles with common sensation and joining in 
the substance of the latter muscle with the facial nerve. The cutaneous branches, 
two in number, an inner and an outer, supply the integument of the cranium as far 
back as the occiput. They are at first situated beneath the Occipito-frontalis, the 
inner branch perforating the frontal portion of the muscle, the outer branch its ten- 
dinous aponeurosis. The pericranial branches are distributed to the pericranium 
over the frontal and parietal bones. They are derived from the cutaneous branches 
whilst beneath the muscle. 
The Nasal Nerve is intermediate in size between the frontal and lachrymal, and 
more deeply placed than the other branches of the ophthalmic. It enters the orbit 
between the two heads of the External rectus, and passes obliquely inward across 
the optic nerve, beneath the Levator palpebrse and Superior rectus muscles, to the 
inner wall of the orbit, where it enters the anterior ethmoidal foramen, immediately 
below the Superior oblique. It then enters the cavity of the cranium, traverses a 
shallow groove on the front of the cribriform plate of the ethmoid bone, and passes 
down, through the slit by the side of the crista galli, into the nose, where it divides 
into two branches, an internal and an external. The internal branch supplies the 
mucous membrane near the fore part of the septum of the nose. The external 
branch descends in a groove on the inner surface of the nasal bone, and supplies a 
few filaments to the mucous membrane covering the fore part of the outer wall of 
Lachrymal. 
Frontal. 
Nasal. 
1 The student should remember that the first two divisions of the fifth nerve are purely sensory, 
and that in the text, when branches are described from these two divisions as supplying muscles, it is 
only with sensation,'and that these nerves are not their true motor supply. 722 
CRANIAL NERVES. 
the nares as far as the inferior spongy bone; it then leaves the cavity of the nose 
between the lower border of the nasal bone and the upper lateral cartilage of the 
nose, and, passing down beneath the Compressor nasi, supplies the integument of 
the ala and the tip of the nose, joining with the facial nerve. 
The branches of the nasal nerve are the ganglionic, ciliary, and infratrochlear. 
[Fig. 486. 
Hid nerve. 
Ciliary nerves. 
Lachrymal nerve. 
Frontal nerve. 
Nasal nerve. 
Orbital nerve. 
Infraorbital nerve. 
Vth nerve f Sensory root, 
vtn nerve. Motor root 
Dental branches. 
Facial nerve 
Glosso-pharyngeal nerve. 
Inferior dental nerve. 
Lingual nerve. 
Dental branches. 
Mental nerve. 
Mylo-hyoid nerve. 
G, Ganglion of Gasser. 
C. Ciliary ganglion. 
M, Meckel's ganglion. 
O, Otic ganglion. 
S M, Submaxillary ganglion. 
I, First or ophthalmic division of fifth passing through 
the sphenoidal fissure. 
II, Second or superior maxillary division of fifth pass- 
ing through the foramen rotundum. 
III, Third or inferior maxillary division of fifth (con- 
taining all the motor root) passing through the 
foramen ovale. 
Motor roots of the ganglia. 
Sensory roots of the ganglia. 
Sympathetic roots of the ganglia. 
a, Spheno-palatine nerves. 
b, Posterior dental nerve. 
c, Anterior dental nerve. 
Diagram of the Fifth Nerve and its Ganglia. 
d, Auriculo-temporal nerve. 
e, Greater (or large) superficial petrosal nerve, which, 
after it is joined by the sympathetic branch 
from the carotid plexus, becomes the Vidian 
(v) and goes to the ganglion of Meckel (M). 
f, Lesser (or small) superficial petrosal going to the 
otic ganglion (O). 
g, g, Chorda tympani nerve going to join the inferior 
dental, and thence to the submaxillary gang- 
lion (S M). 
h, Branch of Jacobson's nerve (glosso-pharyngeal), 
which joins the lesser superficial petrosal nerve. 
m, Muscular branches to muscles of mastication. 
n, Naso-palatine nerve. 
p, Palatine nerves, the anterior anastomosing with 
the naso-palatine. 
v, Vidian nerve. 
The three foramina of exit of the fifth nerve on the face are indicated by small circles on the frontal, infra- 
orbital, and mental nerves.-W. W. K.] 
The ganglionic is a slender branch, about half an inch in length, which usually 
arises from the nasal between the two heads of the External rectus. It passes for- 
ward on the outer side of the optic nerve, and enters the superior and posterior angle 
of the ciliary ganglion, forming its superior or long root. It is sometimes joined by 
a filament from the cavernous plexus of the sympathetic or from the superior division 
of the third nerve. 
The long ciliary nerves, two or three in number, are given off from the nasal as 
it crosses the optic nerve. They join the short ciliary nerves from the ciliary gang- 
lion, pierce the posterior part of the sclerotic, and, running forward between it and 
the choroid, are distributed to the ciliary muscle and iris. 
The infratrochlear branch is given off just as the nasal nerve passes through the 
anterior ethmoidal foramen. It runs forward along the upper border of the Internal 
rectus, and is joined beneath the pulley of the Superior oblique by a filament from 
the supratrochlear nerve. It then passes to the inner angle of the eye, and supplies 
the integument of the eyelids and side of the nose, the conjunctiva, lachrymal sac, 
and caruncula lachrymalis. 
Connected with the three divisions of the fifth nerve are four small ganglia. 
With the first division is connected the ophthalmic ganglion; with the second divis- 
Ophthalmic, Lenticular, or Ciliary Ganglion (Fig. 485) SUPERIOR MAXILLARY NERVE. 
723 
ion, the spheno-palatine or Meckel's ganglion; and with the third, the otic and sub- 
maxillary ganglia. All the four receive sensitive filaments from the fifth, and motor 
and sympathetic filaments from various sources; these filaments are called the roots 
of the ganglia. The ganglia are also connected with the cervical portion of the 
sympathetic. 
The Ophthalmic, Lenticular, or Ciliary Ganglion is a small, quadrangular, 
flattened ganglion, of a reddish-gray color and about the size of a pin's head, situ- 
ated at the back part of the orbit between the optic nerve and the External rectus 
muscle, lying generally on the outer side of the ophthalmic artery. It is enclosed in 
a quantity of loose fat, which makes its dissection somewhat difficult. 
Its branches of communication or roots are three, all of which enter its posterior 
border. One, the long root [sensory], is derived from the nasal branch of the oph- 
thalmic, and joins its superior angle. The second, the short root [motor], is a short 
thick nerve, occasionally divided into two parts, which is derived from the branch 
of the third nerve for the Inferior oblique muscle, and is connected with the inferior 
angle of the ganglion. The third, the sympathetic root, is a slender filament from 
the cavernous plexus of the sympathetic. This is frequently blended with the long 
root, but sometimes passes to the ganglion separately. According to Tiedemann, this 
ganglion receives a filament of communication from the spheno-palatine ganglion. 
Its branches of distribution are the short ciliary nerves. These are delicate fila- 
ments, from six to ten in number, which arise from the fore part of the ganglion in 
two bundles, connected with its superior and inferior angles; the lower bundle is 
the larger. They run forward with the ciliary arteries in a wavy course, one set 
above and the other below the optic nerve, and are joined by the long ciliary from 
the nasal. They pierce the sclerotic at the back part of the globe, pass forward in 
delicate grooves on its inner surface, and are distributed to the ciliary muscle and 
iris. A small filament is described by Tiedemann, penetrating the optic nerve with 
the arteria centralis retinae. 
Superior Maxillary Nerve (Fig. 487). 
The Superior Maxillary, or second division of the fifth, is a sensory nerve. It 
is intermediate, both in position and size, between the ophthalmic and inferior max- 
illary. It commences at the middle of the Gasserian ganglion as a flattened plexi- 
form band, and passes forward through the foramen rotundum, where it becomes 
more cylindrical in form and firmer in texture. It then crosses the spheno-maxil- 
lary fossa, enters the orbit through the spheno-maxillary fissure, traverses the infra- 
orbital canal in the floor of the orbit, and appears upon the face at the infraorbital 
foramen.1 At its termination the nerve lies beneath the Levator labii superioris 
muscle, and divides into a leash of branches, which spread out upon the side of the 
nose, the lower eyelid, the upper lip, joining with filaments of the facial nerve. 
The branches of this nerve may be divided into three groups: 1, those given 
off in the spheno-maxillary fossa; 2, those in the infraorbital canal; 3, those on 
the face. 
Orbital or Temporo-malar. 
Spheno-palatine. 
Posterior Dental. 
Spheno-maxillary fossa - 
Infraorbital canal . Anterior Dental. 
Palpebral. 
Nasal. 
Labial. 
On the face . 
In addition to these named branches the superior maxillary nerve frequently 
gives off a minute recurrent branch directly after its origin from the Gasserian 
ganglion, which supplies the dura mater. 
The orbital or temporo-malar branch arises in the spheno-maxillary fossa, 
1 After it enters the infraorbital canal the nerve is frequently called the infraorbital. 724 
CRANIAL NERVES. 
enters the orbit by the spheno-maxillary fissure, and divides at the back of that 
cavity into two branches, temporal and malar. 
The temporal branch runs in a groove along the outer wall of the orbit (in the 
malar bone), receives a branch of communication from the lachrymal, and, passing 
through a foramen in the malar bone, enters the temporal fossa. It ascends 
Fig. 487. 
Sensory Hoot 
HTcrtor 
Spheno-palatine or 
Meckel's Ganglion 
Auricula -Urnpfral N. > 
Distribution of the Second and Third Divisions of the Fifth Nerve and Submaxillary Ganglion. 
between the bone and substance of the Temporal muscle, pierces this muscle and 
the temporal fascia about an inch above the zygoma, and is distributed to the 
integument covering the temple and side of the forehead, communicating with the 
facial and auriculo-temporal branch of the inferior maxillary nerve. As it pierces 
the temporal fascia it gives off a slender twig which runs between the two layers of 
the fascia to the outer angle of the orbit. 
The malar branch passes along the external inferior angle of the orbit, emerges 
upon the face through a foramen in the malar bone, and, perforating the Orbicu- 
laris palpebrarum muscle, supplies the skin on the prominence of the cheek, and is 
named subcutaneous malce. It joins with the facial and the palpebral branches of 
the superior maxillary. 
The spheno-palatine branches, two in number, descend to the spheno-palatine 
ganglion. 
The posterior dental branches arise from the trunk of the nerve just as it is 
about to enter the infraorbital- canal; they are generally two in number, but. some- 
times arise by a single trunk, and immediately divide and pass downward on the 
tuberosity of the superior maxillary bone. One of them enters a canal in the sub- 
stance of the superior maxillary bone, passes from behind forward, and joins oppo- 
site the canine fossa with the anterior dental. Numerous filaments are given off 
from the lower border of this nerve, which form a minute plexus in the outer wall SPHENO-PALATINE GANGLION. 
725 
of the superior maxillary bone immediately above the alveoli. From this plexus 
filaments are distributed to the pulp of the molar teeth, the lining membrane of the 
antrum, and corresponding portion of the gums. The other branch is distributed 
to the gums and mucous membrane of the cheek. 
The anterior dental, of large size, is given off from the superior maxillary 
nerve just before its exit from the infraorbital foramen; it enters a special canal in 
the anterior wall of the antrum and communicates with the posterior dental. In its 
course through its special canal it gives off a branch which is sometimes called the 
middle dental, which supplies the bicuspid teeth. Occasionally this branch is given 
off directly from the superior maxillary nerve in the back part of the infraorbital 
canal, and runs in a special canal to the bicuspid teeth. Other filaments of the 
anterior dental nerve are distributed to the canine and incisor teeth, and others are 
lost upon the lining membrane covering the fore part of the inferior meatus. In 
this situation it forms a communication with a nasal branch from Meckel's ganglion 
[marked by a swelling], called the ganglion of Bochdalek. 
The palpebral branches pass upward beneath the Orbicularis palpebrarum. 
They supply this muscle, the integument, and conjunctiva of the lower eyelid with 
sensation, joining at the outer angle of the orbit with the facial nerve and malar 
branch of the orbital. 
The nasal branches pass inward; they supply the integument of the side of 
the nose, and join with the nasal branch of the ophthalmic. 
The labial branches, the largest and most numerous, descend beneath the Leva- 
tor labii superioris, and are distributed to the integument and muscles of the upper 
lip, the mucous membrane of the mouth, and labial glands. 
All these branches are joined, immediately beneath the orbit, by filaments from 
the facial nerve, forming an intricate plexus, the infraorbital. 
Spheno-palatine or Meckel's Ganglion (Figs. 487, 488). 
The Spheno-palatine Ganglion (Meckel's), the largest of the cranial ganglia, 
is deeply placed in the spheno-maxillary fossa, close to the spheno-palatine foramen. 
It is triangular or heart-shaped, of a reddish-gray color, and is situated just below 
the superior maxillary nerve as it crosses the fossa. The two spheno-palatine 
branches of this nerve descend to the ganglion; the fibres derived from them for 
the most part pass in front of the ganglion as they proceed to their destination in 
the palate and nasal fossa, and are not incorporated in the ganglionic mass; some 
few of the fibres, however, enter the ganglion, constituting its sensory root. Like 
the other ganglia of the fifth nerve, it possesses a motor, a sensory, and a sympa- 
thetic root. Its motor root is derived from the facial through the Vidian, its sensory 
root from the fifth, and its sympathetic root from the carotid plexus through the 
Vidian. Its branches are divisible into four groups: ascending, which pass to the 
orbit; descending, to the palate; internal, to the nose; and posterior branches, to 
the pharynx. 
The ascending branches are two or three delicate filaments which enter the orbit 
by the spheno-maxillary fissure and supply the periosteum. Arnold describes and 
delineates these branches as ascending to the optic nerve. Bock describes a branch 
as going to the cavernous sinus to communicate with the sixth nerve, and Tiede- 
mann a communicating branch to the ophthalmic ganglion. 
The descending or palatine branches are distributed to the roof of the mouth, 
the soft palate, tonsil, and lining membrane of the nose. They are almost a direct 
continuation of the spheno-palatine branches of the superior maxillary nerve, and 
are three in number-anterior, middle, and posterior. 
The anterior or large palatine nerve descends through the posterior palatine 
canal, emerges upon the hard palate at the posterior palatine foramen, and passes 
forward through a groove in the hard palate nearly as far as the incisor teeth. It 
supplies the gums, the mucous membrane and glands of the hard palate, and com- 
municates in front with the termination of the naso-palatine nerve. While in the 726 
CRANIAL NERVES. 
posterior palatine canal it gives off inferior nasal branches, which enter the nose 
through openings in the palate bone, and ramify over the middle meatus and the 
middle and inferior spongy bones; and at its exit from the canal a palatine branch 
is distributed to both surfaces of the soft palate. 
The middle or external palatine nerve descends, in the same canal as the pre- 
ceding, to the posterior palatine foramen, distributing branches to the uvula, tonsil, 
and soft palate. It is occasionally wanting. 
The posterior or small palatine nerve descends with a small artery through the 
small posterior palatine canal, emerging by a separate opening behind the posterior 
Fig. 488. 
Sphmo-palatine, or 
Meckel's Ganglion 
Term? of 
Haso-PalHono&rVl- 
The Spheno-palatine Ganglion and its Branches. 
palatine foramen. It supplies the Levator palati and Azygos uvulae muscles, the 
soft palate, tonsil, and uvula. The middle and posterior palatine join with the ton- 
sillar branches of the glosso-pharyngeal to form the plexus around the tonsil (circulus 
tonsillaris). One of these palatine nerves usually supplies the Palato-glossus and 
Palato-pharyngeus muscles. 
The internal branches are distributed to the septum and outer wall of the nasal 
fossae. They are the superior nasal (anterior) and the naso-palatine. 
The superior nasal branches (anterior), four or five in number, enter the back 
part of the nasal fossa by the spheno-palatine foramen. They supply the mucous 
membrane covering the superior and middle spongy bones and that lining the pos- 
terior ethmoidal c.ells, a few being prolonged to the upper and back part of the sep- 
tum. One of these branches (the posterior) is continued on to the wall of the antrum, 
and there forms a communication with the anterior dental nerve. At the point of 
communication a swelling exists, denominated "the ganglion of Bochdalek," the 
nature of which seems, however, uncertain. 
The naso-palatine nerve (Cotunnius) enters the nasal fossa with the other nasal 
nerves, and passes inward across the roof of the nose, below the orifice of the sphe- 
noidal sinus, to reach the septum; it then runs obliquely downward and forward 
along the lower part of the septum to the anterior palatine foramen, lying between 
the periosteum and mucous membrane. It descends to the roof of the mouth through 
the anterior palatine canal. The two nerves are here contained in separate and dis- INFERIOR MAXILLARY NERVE. 
727 
tinct canals situated in the intermaxillary suture and termed the foramina of Scarpa, 
the left nerve being usually anterior to the right one. In the mouth they become 
united, supply the mucous membrane behind the incisor teeth, and join with the 
anterior palatine nerve. The naso-palatine nerve occasionally furnishes a few small 
filaments to the mucous membrane of the septum. 
The posterior branches are the Vidian and the pharyngeal (pterygo-palatine). 
The Vidian nerve, if traced from Meckel's ganglion, may be said to arise from 
the back part of the ganglion, and then to pass through the Vidian canal, entering 
the cartilage filling in the foramen lacerum [medium] basis cranii and dividing into 
two branches, the large superficial petrosal and the deep petrosal. In its course 
along the Vidian canal it distributes a few filaments to the lining membrane at the 
back part of the roof of the nose and septum and that covering the end of the 
Eustachian tube. These are upper posterioi' nasal branches. 
The large superficial petrosal branch (nervus petrosus superficialis major) enters 
the cranium through the foramen lacerum [medium] basis cranii, having pierced the 
cartilaginous substance which fills in this aperture. It runs beneath the Gasserian 
ganglion and dura mater, contained in a groove on the anterior surface of the petrous 
portion of the temporal bone, enters the hiatus Fallopii, where it receives a com- 
municating branch from Jacobson's nerve, and, being continued through it into the 
aquaeductus Fallopii, joins the gangliform enlargement on the facial nerve. Prop- 
erly speaking, this nerve passes from the facial to the spheno-palatine ganglion, 
forming its motor root. 
The deep petrosal branch (nervus petrosus profundus') is shorter but larger than 
the other, of a reddish-gray color, and soft in texture. It crosses the foramen 
lacerum surrounded by the cartilaginous substance which fills in that aperture, and 
enters the carotid canal on the outei- side of the carotid artery to join the carotid 
plexus. 
This description of the Vidian nerve as a branch from the ganglion is the more 
convenient anatomically inasmuch as the nerve is generally dissected from the 
ganglion as a single trunk dividing into two branches. But it is more correct, 
physiologically, to describe the Vidian as being formed by the union of the two 
branches (great petrosal and deep petrosal) from the facial and the sympathetic, 
and as running into the ganglion. The filaments which are described above as given 
off from the Vidian nerve would then be regarded as branches from the ganglion 
which are merely enclosed in the same sheath as the Vidian. 
The pharyngeal nerve (pterygo-palatine) is a small branch arising from the 
back part of the ganglion, occasionally together with the Vidian nerve. It passes 
through the pterygo-palatine canal with the pterygo-palatine artery, and is dis- 
tributed to the mucous membrane of the upper part of the pharynx behind the 
Eustachian tube. 
Inferior Maxillary Nerve (Fig. 487, p. 724). 
The Inferior Maxillary Nerve distributes branches to the teeth and gums of 
the lower jaw, the integument of the temple and external ear, the lower part of the 
face and lower lip, and the muscles of mastication: it also supplies the tongue with 
a large branch which may possibly serve as a nerve of the special sense of taste. 
It is the largest of the three divisions of the fifth, and consists of two portions- 
the large or sensory root proceeding from the inferior angle of the Gasserian 
ganglion, and the small or motor root, which passes beneath the ganglion and 
unites with the sensory division just after its exit through the foramen ovale. 
Immediately beneath the base of the skull this nerve divides into two trunks, 
anterior and posterior. 
The anterior and smaller division, which receives nearly the whole of the motor 
root, divides into branches which supply the muscles of mastication. They are the 
masseteric, deep temporal, buccal, and two pterygoid. 
The masseteric branch passes outward, above the External pterygoid muscle, 728 
CRANIAL NERVES. 
in front of the temporo-maxillary articulation, and crosses the sigmoid notch with 
the masseteric artery to the Masseter muscle, in which it ramifies nearly as far as 
its anterior border. It occasionally gives a branch to the Temporal muscle and a 
filament to the articulation of the jaw. 
The deep temporal branches, two in number, anterior and posterior, supply 
the deep surface of the Temporal muscle. The branch, of small size, is 
placed at the back of the temporal fossa. It is sometimes joined with the mas- 
seteric branch. The anterior branch is reflected upward, at the pterygoid ridge of 
the sphenoid, to the front of the temporal fossa. It is generally given off from the 
buccal nerve. Sometimes there are three deep temporal branches. 
The buccal branch pierces the External pterygoid, and passes downward 
beneath the inner surface of the coronoid process of the lower jaw or through 
the fibres of the Temporal muscle to reach the surface of the Buccinator, upon 
which it divides into a superior and an inferior branch. It gives a branch to the 
External pterygoid during its passage through the muscle, and a few ascending 
filaments to the Temporal muscle, one of which occasionally joins with the anterior 
branch of the deep temporal nerve. The upper branch supplies the integument and 
upper part of the Buccinator muscle, joining with the facial nerve round the facial 
vein. The lower branch passes forward to the angle of the mouth; it supplies the 
integument and Buccinator muscle, as well as the mucous membrane lining the 
inner surface of that muscle, and joins the facial nerve.1 
The pterygoid branches are two in number, one for each pterygoid muscle. 
The branch to the Internal pterygoid is long and slender, and passes inward to 
enter the deep surface of the muscle. This nerve is intimately connected at its 
origin with the otic ganglion. The branch to the External pterygoid is most 
frequently derived from the buccal, but it may be given off separately from the 
anterior trunk of the nerve. 
The posterior and larger division of the inferior maxillary nerve is for the most 
part sensory, but receives a few filaments from the motor root. It divides into 
three branches-auriculo-temporal, gustatory, and inferior dental. 
The Auriculo-temporal Nerve generally arises by two roots, between which 
the middle meningeal artery passes. It runs backward beneath the External ptery- 
goid muscle to the inner side of the neck of the lower jaw. It then turns upward 
with the temporal artery, between the external ear and condyle of the jaw, under 
cover of the parotid gland, and, escaping from beneath this structure, ascends over 
the zygoma and divides into two temporal branches. The posterior temporal, the 
smaller of the two, is distributed to the upper part of the pinna and the neighbor- 
ing tissues. The anterior temporal accompanies the temporal artery to the vertex 
of the skull, and supplies the integument of the temporal region, communicating 
with the facial nerve and orbital branch of the superior maxillary. 
The auriculo-temporal nerve has branches of communication with the facial and 
otic ganglion. Those joining the facial nerve, usually two in number, pass forward 
from behind the neck of the condyle of the jaw to join this nerve at the posterior 
border of the Masseter muscle. They form one of the principal branches of com- 
munication between the facial and the fifth nerve. The filaments of communica- 
tion with the otic ganglion are derived from the commencement of the auriculo- 
temporal nerve. 
It gives off auricular branches, two in number, inferior and superior. The 
inferior auricular arises behind the articulation of the jaw, and is distributed 
to the ear below the external meatus; other filaments twine round the internal 
maxillary artery and communicate with the sympathetic. The superior auricular 
arises in front of the external ear and supplies the integument covering the tragus 
and pinna. 
Branches to the meatus auditorius, two in number, arise from the point of com- 
1 There seems to be no reason to donbt that the branch supplying the Buccinator muscle is 
entirely a nerve of ordinary sensation, and that the true motor supply of this muscle is from the 
facial. OTIC GANGLION. 
729 
munication between the auriculo-temporal and facial nerves, and are distributed to 
the meatus. 
A branch to the temporo-maxillary articulation is usually derived from the 
auriculo-temporal nerve. 
Parotid branches, which supply the parotid gland, are also given off from this nerve. 
The Lingual or Gustatory1 Nerve supplies the papillae and mucous membrane 
of the tongue. It is deeply placed throughout the whole of its course. It lies at 
first beneath the External pterygoid muscle, together with the inferior dental nerve, 
being placed to the innei' side of the latter nerve, and is occasionally joined to it 
by a branch which crosses the internal maxillary artery. The chorda tympani also 
joins it at an acute angle in this situation. The nerve then passes between the 
Internal pterygoid muscle and the inner side of the ramus of the jaw, and crosses 
obliquely to the side of the tongue over the Superior constrictor muscle of the 
pharynx, and between the Stylo-glossus muscle and deep part of the submaxillary 
gland; the nerve lastly runs across Wharton's duct and along the side of the 
tongue to its apex, lying immediately beneath the mucous membrane. [As it 
passes to the side of the base of the tongue it is accessible for operation.] 
Its branches of communication are with the facial through the chorda tympani, 
the inferior dental and hypoglossal nerves, and the submaxillary ganglion. The 
branches to the submaxillary ganglion are two or three in number; those connected 
with the hypoglossal nerve form a plexus at the anterior margin of the Hyo-glossus 
muscle. 
Its branches of distribution are few in number. They supply the mucous mem- 
brane of the mouth, the gums, the sublingual gland, the filiform and fungiform 
papillae, and mucous membrane of the tongue, the terminal filaments anastomosing 
at the tip of the tongue with the hypoglossal nerve. 
The inferior dental is the largest of the three branches of the inferior maxil- 
lary nerve. It passes downward with the inferior dental artery, at first beneath 
the External pterygoid muscle, and then between the internal lateral ligament and 
the ramus of the jaw to the dental foramen. It then passes forward in the dental 
canal of the inferior maxillary bone, lying beneath the teeth, as far as the mental 
foramen, where it divides into two terminal branches, incisor and mental. [In this 
canal the nerve can be reached for operation by removal of the external layer of 
the lower jaw-bone.] The incisor branch is continued onward within the bone to 
the middle line, and supplies the canine and incisor teeth. The mental branch 
emerges from the bone at the mental foramen, and divides beneath the Depressor 
anguli oris into two or three branches: one descends to supply the skin of the chin, 
and another (sometimes two) ascends to supply the skin and mucous membrane of 
the lower lip. These branches communicate freely with the facial nerve. 
The branches of the inferior dental are the mylo-hyoid and dental. 
The mylo-hyoid is derived from the inferior dental just as that nerve is about to 
enter the dental foramen. It descends in a groove on the inner surface of the ramus 
of the jaw, in which it is retained by a process of fibrous membrane. It supplies the 
cutaneous surface of the Mylo-hyoid muscle and the anterior belly of the Digastric, 
occasionally sending one or two filaments to the submaxillary gland. 
The dental branches supply the molar and bicuspid teeth. They correspond in 
number to the fangs of those teeth, each nerve entering the orifice at the point of 
the fang and supplying the pulp of the tooth. 
Two small ganglia are connected with the inferior maxillary nerve-the otic with 
the trunk of the nerve, and the submaxillary with its lingual branch, the gustatory. 
The Otic Ganglion (Arnold's) is a small, oval-shaped, flattened ganglion of a 
reddish-gray color situated immediately below the foramen ovale, on the inner sur- 
Otic Ganglion (Fig. 489). 
f1 It is much better to call this the Lingual Nerve. It is certainly distributed to the tongue, but 
its function as to taste is dubious.] 730 
CRANIAL NERVES. 
face of the inferior maxillary nerve and round the origin of the internal pterygoid 
nerve. It is in relation externally with the trunk of the inferior maxillary nerve 
at the point where the motor root joins the sensory portion; internally with the 
Fig. 489. 
The Otic Ganglion and its Branches. 
cartilaginous part of the Eustachian tube and the origin of the Tensor palati mus- 
cle ; behind it is the middle meningeal artery. 
Branches of Communication.-This ganglion is connected with the inferior max- 
illary nerve and its internal pterygoid branch by two or three short, delicate fila- 
ments, and also with the auriculo-temporal nerve. From the former it obtains its 
motor, from the latter its sensory root,1 its communication with the sympathetic 
being effected by a filament from the plexus surrounding the middle meningeal 
artery. This ganglion also communicates with the glosso-pharyngeal and facial 
nerves through the small petrosal nerve continued from the tympanic plexus 
(p. 738). 
Its branches of distribution are a filament to the Tensor tympani, and one to the 
Tensor palati. The former passes backward, on the outer side of the Eustachian 
tube; the latter arises from the ganglion, near the origin of the internal pterygoid 
nerve, and passes forward. It also gives off a small communicating branch to the 
chorda tympani. 
Submaxillary Ganglion (Fig. 487, p. 724). 
The Submaxillary Ganglion is of small size, fusiform in shape, and situated 
above the deep portion of the submaxillary gland near the posterior border of the 
Mylo-hyoid muscle, being connected by filaments with the lower border of the gus- 
tatory nerve. 
Branches of Communication.-This ganglion is connected with the gustatory 
nerve by a few filaments which join it separately at its fore and back part. It also 
receives a branch from the chorda tympani, by which it. communicates with the 
facial, and communicates with the sympathetic by filaments from the sympathetic 
plexus around the facial artery. 
1 Experiments on animals seem to prove that this is not the sensory root of the ganglion, but 
rather a branch of distribution passing from the otic ganglion to the auriculo-temporal nerve, and 
through it to the parotid gland. It probably receives its sensory root from the glosso-pharyngeal 
nerve. (See p. 738.) SIXTH NERVE. 
731 
Branches of Distribution.-These are five or six in number; they arise from 
the lower part of the ganglion and supply the mucous membrane of the mouth and 
Wharton's duct, some being lost in the submaxillary gland. According to Meckel, 
a branch from this ganglion occasionally descends in front of the Hyo-glossus mus- 
cle, and, after joining with one from the Hypoglossal, passes to the Genio-hyo-glossus 
muscle. 
[Fig. 490 shows the distribution of the sensory branches of the fifth nerve to 
the skin of the head and neck. 
[Fig. 490. 
First division of the fifth: 
SO, Supraorbital. 
ST, Supratrochlear. 
IT, Infratrochlear. 
L, Lachrymal. 
N, Nasal. 
Second division of the fifth : 
IO, Infraorbital. 
TM, Temporo-malar. 
Sensory Nerves of the Head and Face. 
Third division of the fifth : 
B, Buccal. 
M, Mental. 
AT, Auriculo-temporal. 
Branches of the cervical plexus: 
GO, Great occipital. 
S'O', Small occipital. 
GA, Great auricular. 
SC, Superficial cervical. 
IIIC, Third cervical (Flower).] 
The sixth or Abducens Nerve supplies the External rectus muscle. Its appa- 
rent origin is by several filaments from the constricted part of the corpus pyramidale 
close to the pons, or from the lower border of the pons itself in the groove between 
this body and the medulla. The deep origin of this nerve is from the gray substance 
of the fasciculus teres, on the floor of the fourth ventricle, from a nucleus common to 
it and a part of the facial nerve. 
The nerve pierces the dura mater on the basilar surface of the sphenoid bone, 
runs through a notch immediately below the posterior clinoid process, and enters 
the cavernous sinus. It passes forward through the sinus, lying on the outer side 
of the internal carotid artery, where it is joined by several filaments from the 
carotid and cavernous plexus, by one from Meckel's ganglion (Bock), and another 
ffom the ophthalmic nerve. It enters the orbit through the sphenoidal fissure, and 
lies above the ophthalmic vein, from which it is separated by a lamina of dura 
mater. It then passes between the two heads of the External rectus, and is dis- 
tributed to that muscle on its ocular surface. 
The above-mentioned nerve, as well as the third, fourth, and the ophthalmic 
division of the fifth, as they pass to the orbit bear a certain relation to each other 
in the cavernous sinus, at the sphenoidal fissure, and in the cavity of the orbit, 
which will be now described. 
Sixth Nerve (Fig. 485, p. 720). 732 
CRANIAL NERVES. 
In the cavernous sinus (Fig. 413, p. 621) the third, fourth, and ophthalmic 
division of the fifth are placed in the dura mater of the outer wall of the sinus in 
their numerical order, both from above downward and from within outward. The 
sixth nerve lies at the outer side of the internal carotid artery. As these nerves 
pass forward to the sphenoidal fissure the third and fifth nerves become divided into 
branches, and the sixth approaches the rest, so that their relative position becomes 
considerably changed. 
In the sphenoidal fissure (Fig. 491) the fourth and the frontal and lachrymal 
divisions of the ophthalmic lie upon the same plane, the former being most inter- 
nal, the latter external, and they enter the cavity of the orbit above the muscles. 
The remaining nerves enter the or- 
bit between the two heads of the 
External rectus. The superior di- 
vision of the third is the highest of 
these; beneath this lies the nasal 
branch of the fifth; then the infe- 
rior division of the third; and the 
sixth lowest of all. 
In the orbit the fourth and the 
frontal and lachrymal divisions of 
the ophthalmic lie on the same 
plane immediately beneath the pe- 
riosteum, the fourth nerve being 
internal and resting on the Supe- 
rior oblique, the frontal resting on 
the Levator palpebrse, and the lach- 
rymal on the External rectus. Next 
in order comes the superior division of the third nerve, lying immediately beneath 
the Superior rectus, and then the nasal division of the fifth, crossing the optic nerve 
from the outer to the inner side of the orbit. Beneath these is found the optic nerve, 
surrounded in front by the ciliary nerves and having the lenticular ganglion on its 
outer side between it and the External rectus. Below the optic is the inferior divis- 
ion of the third and the sixth, which lies on the outer side of the orbit. 
Fig. 491. 
LACRYMAU 
FRONTAu 
TH 
SUPERIOR DIVISION OF 350 
INASAL 
DIVISION OF 3ffp 
-6th 
'OPIil HALMIC VEIN 
Relations of Structures through the Sphenoidal 
Seventh Nerve (Figs. 492, 493). 
The seventh or Facial Nerve (portio dura of the seventh pair of Willis) [so 
called from its greater hardness as compared with the auditory nerve, which is the 
portio mollis, or "soft portion"] is the motor nerve of all the muscles of expression 
in the face and of the Platysma and Buccinator. It also supplies two of the mus- 
cles of the external ear, the poste- 
rior belly of the Digastric and 
the Stylo-hyoid. Through the 
chorda tympani it supplies the 
Lingualis; by its tympanic branch, 
the Stapedius; through the otic 
ganglion, the Tensor tympani; 
and through the connection of its 
trunk with the Vidian nerve b'y 
the petrosal nerve it probably 
supplies the Levator palati and 
Azygos uvulae. It arises from 
the lateral tract of the medulla oblongata in the groove between the olivary and 
restiform bodies. Its deep origin is twofold: 1, from the gray substance of the 
fasciculus teres on the floor of the fourth ventricle, in common with the sixth nerve; 
2, from the nucleus of the motor root of the trigeminus. Between these two origins 
it forms a loop along the floor of the ventricle. This nerve is situated a little nearer 
Fig. 492. 
External Petrosal 
Small Petrosal- 
.Large Petrosal'-■ 
Inlumescentici Ganghjbrmii 
•ptppr ( J'accaZ.UI, 
* " " [Auditory 
The Course and Connections of the Facial Nerve in the Tem- 
poral Bone. SEVENTH NERVE. 
733 
to the middle line than the portio mollis, close to the lower border of the pons Varo- 
lii, from which some of its fibres are derived. 
Connected with this nerve, and lying between it and the portio mollis, is a small 
fasciculus (portio inter dur am et mollem of Wrisberg, or pars intermedia'). This 
accessory portion arises from the lateral column of the cord. 
The nerve passes forward and outward upon the crus cerebelli, and enters the 
internal auditory meatus with the auditory nerve. Within the meatus the facial 
nerve lies first to the inner side of the auditory, and then in a groove upon that 
nerve, and is connected to it by one or two filaments. 
At the bottom of the meatus it enters the aquseductus Fallopii, and follows the 
serpentine course of that canal through the petrous portion of the temporal bone, 
from its commencement at the internal meatus to its termination at the stylo-mastoid 
foramen. [Its passage through this rigid, unyielding bony canal may explain its 
frequent paralysis from neuritis.] It is at first directed outward toward the hiatus 
Fallopii, where it forms a reddish gangliform swelling (intumescentia gangliformis 
or geniculate ganglion), and is joined by several nerves; then, bending suddenly 
backward, it runs in the internal wall of the tympanum above the fenestra ovalis, 
and at the back of that cavity passes vertically downward to the stylo-mastoid 
foramen. 
On emerging from this aperture it runs forward in the substance of the parotid 
gland, crosses the external carotid artery, and divides behind the ramus of the 
lower jaw into two primary branches, temporo-facial and cervico-facial, from which 
numerous offsets are distributed over the side of the head, face, and upper part of 
the neck, supplying the' superficial muscles in these regions. As the primary 
branches and their offsets diverge from each other, they present somewhat the 
appearance of a bird's claw; hence the name of pes anserinus is given to the 
division of the facial nerve in and near the parotid gland. [Just after its emer- 
gence from the stylo-mastoid foramen it is accessible for operation.1] 
The communications of the facial nerve may be thus arranged: 
In the internal auditory meatus . With the auditory nerve. 
With Meckel's ganglion by the large 
petrosal nerve. 
With the otic ganglion by the small 
petrosal nerve. 
With the sympathetic on the middle me- 
ningeal by the external petrosal nerve. 
In the aquaeductus Fallopii. 
With the glosso-pharyngeal. 
" pneumogastric. 
" carotid plexus. 
" auricularis magnus. 
" auriculo-temporal. 
At its exit from the stylo-mastoid 
foramen . . . . 
On the face .... With the three divisions of the fifth. 
In the internal auditory meatus some minute filaments pass between the facial 
and auditory nerves. 
Opposite the hiatus Fallopii the gangliform enlargement on the facial nerve com- 
municates, by means of the large petrosal nerve, with Meckel's ganglion, forming 
its motor root; by a filament from the small petrosal with the otic ganglion; and 
by the external petrosal with the sympathetic filaments accompanying the middle 
meningeal artery (Bidder). From the gangliform enlargement, according to Arnold, 
a twig is sent back to the auditory nerve. 
At its exit from the stylo-mastoid foramen it sends a twig to the glosso-pharyn- 
geal, another to the pneumogastric nerve, and communicates with the carotid plexus 
of the sympathetic, with the great auricular branch of the cervical plexus, with the 
auriculo-temporal branch of the inferior maxillary nerve in the parotid gland, and 
on the face with the terminal branches of the three divisions of the fifth. 
[i See a paper by the American Editor in the Trans. Amer. Surg. Assoc., 1886.] 734 
CRANIAL NERVES. 
Fig. 493. 
Terminations 
•of Supra-trochlear 
__of Infra -trochlear 
of Nasal 
The Nerves of the Scalp, Face, and Side of the Neck. 
Branches of Distribution. 
Tympanic. 
Chorda tympani. 
Within the aquaeductus Fallopii . 
At its exit from the stylo-mastoid 
foramen .... 
Posterior auricular. 
Digastric. 
Stylo-hyoid. 
' Temporal. 
Malar. 
Infraorbital. 
Temporo-facial. 
On the face 
Buccal. 
Supramaxillary. 
Inframaxillary. 
Cervico-facial. 
The Tympanic branch arises from the nerve opposite the pyramid; it is a 
small filament which supplies the Stapedius muscle. 
The Chorda tympani is given off from the facial as it passes vertically down- 
ward at the back of the tympanum, about a quarter of an inch before its exit from SEVENTH NERVE. 
735 
the stylo-mastoid foramen. It passes from below upward in a distinct canal parallel 
with the aqueeductus Fallopii, and enters the cavity of the tympanum through an 
aperture (iter chordce postering} on its posterior wall between the opening of the 
mastoid cells and the attachment of the membrana tympani, and becomes invested 
with mucous membrane. It passes forward through the cavity of the tympanum, 
between the handle of the malleus and vertical ramus of the incus, to its anterior 
inferior angle, and emerges from that cavity through a foramen at the inner end of 
the Glaserian fissure which is called the iter chordce anterius, or canal of Huguier. 
It then descends between the two Pterygoid muscles, meets the gustatory nerve at 
an acute angle, and accompanies it to the submaxillary gland; part of it then joins 
the submaxillary ganglion ; the rest is continued onward into the proper muscular 
fibres of the tongue-the Lingualis muscle. Before joining the gustatory nerve it 
receives a small communicating branch from the otic ganglion.1 
The Posterior Auricular Nerve arises close to the stylo-mastoid foramen and 
passes upward in front of the mastoid process, where it is joined by a filament from 
the auricular branch of the pneumogastric, and communicates with the deep branch 
of the auricularis magnus and with the small occipital; as it ascends between the 
meatus and mastoid process it divides into two branches. The auricular branch 
supplies the Retrahens aurem. The occipital branch,, the larger, passes backward 
along the superior curved line of the occipital bone and supplies the occipital por- 
tion of the Occipito-frontalis. 
The Stylo-hyoid is a long slender branch which passes inward, entering the 
Stylo-hyoid muscle about its middle; it communicates with the sympathetic fila- 
ments on the external carotid artery. 
The Dig-astric branch usually arises by a common trunk with the preceding; 
it divides into several filaments, which supply the posterior belly of the Digastric; 
one of these perforates that muscle to join the glosso-pharyngeal nerve. 
The Temporo-facial, the larger of the two terminal branches, passes upward 
and forward through the parotid gland, crosses the neck of the condyle of the jaw, 
being connected in this situation with the auriculo-temporal branch of the inferior 
maxillary nerve, and divides into branches which are distributed over the temple 
and upper part of the face; these are divided into three sets, temporal, malar, and 
infraorbital. 
The temporal branches cross the zygoma to the temporal region, supplying the 
Attrahens aurem muscle, and join with the temporal branch of the superior maxil- 
lary and with the auriculo-temporal branch of the inferior maxillary. The more 
anterior branches supply the frontal portion of the Occipito-frontalis and the 
Orbicularis palpebrarum muscle, joining with the supraorbital branch of the 
ophthalmic. 
The malar branches pass across the malar bone to the outer angle of the orbit, 
where they supply the Orbicularis and Corrugator supercilii muscles, joining with 
filaments from the lachrymal and supraorbital nerves; others supply the lower eye- 
lid, joining with filaments of the malar branches (subcutaneous malce) of the supe- 
rior maxillary nerve. 
The infraorbital, of larger size than the rest, pass horizontally forward to be 
distributed between the lower margin of the orbit and the mouth. The superficial 
branches run beneath the skin and above the superficial muscles of the face which 
they supply : some supply the lower eyelid and Pyramidalis nasi, joining at the inner 
angle of the orbit with the infratrochlear and nasal branches of the ophthalmic. 
The deep branches pass beneath the Levator labii superiors, supplying it and the 
Levator anguli oris, and form a plexus (infraorbital)) by joining with the infraorbital 
branch of the superior maxillary nerve and the buccal branches of the cervico-facial. 
[J Sapolini believes that the chorda tympani is an independent thirteenth cranial nerve, originat- 
ing from the intermediate nerve of Wrisberg. He has traced it from the fourth ventricle to the 
geniculate ganglion of the seventh nerve, and from the chorda tympani backward, to the same 
ganglion, and believes these two portions to be one and the same nerve, running with the seventh, 
but anatomically distinct from it. He believes it to be the special nerve of speech.] 736 
CRANIAL NERVES. 
The Cervico-facial division of the facial nerve passes obliquely downward and 
forward through the parotid gland, where it is joined by branches from the great 
auricular nerve; opposite the angle of the lower jaw it divides into branches which 
are distributed on the lower half of the face and upper part of the neck. These 
may be divided into three sets-buccal, supramaxillary, and inframaxillary. 
'The buccal branches cross the Masseter muscle. They supply the Buccinator 
and Orbicularis oris, and join with the infraorbital branches of the temporo-facial 
division of the nerve, and with filaments of the buccal branch of the inferior maxil- 
lar nerve. 
The supramaxillary branches pass forward beneath the Platysma and Depressor 
ano-uli oris, supplying the muscles of the lip and chin and communicating with the 
mental branch of the inferior dental nerve. 
The inframaxillary branches run forward beneath the Platysma, and form a 
series of arches across the side of the neck over the suprahyoid region. One of 
these branches descends vertically to join with the superficial cervical nerve from 
the cervical plexus; others supply the Platysma. 
Eighth Nerve. 
The eighth or Auditory Nerve (pportio mollis of the seventh pair of Willis') is 
the special nerve of the sense of hearing, being distributed exclusively to the inter- 
nal ear. 
The auditory nerve appears at the base of the brain in the groove between the 
olivarv and restiform bodies at the lower border of the pons. It lies external to 
the facial nerve. It has three origins: 1, from the 
superior vermiform process of the cerebellum ; 2 and 3, 
from the inner and outer auditory nuclei formed chiefly 
by the gray substance of the posterior pyramid and 
restiform body. The nerve winds round the restiform 
body, from which it receives fibres, and passes forward 
across the posterior border of the crus cerebelli in com- 
pany with the facial nerve, from which it is partially 
separated by a small artery. It then enters the meatus 
auditorius internus in company with the facial nerve, 
and at the bottom of the meatus divides into two 
branches, cochlear and vestibular, which are distrib- 
uted, the former to the cochlea, the latter to the vesti- 
bule and semicircular canals. The auditory nerve is 
very soft in texture (hence the name portio mollis)., des- 
titute of neurilemma, and within the meatus receives one or two filaments from the 
facial. The distribution of the auditory nerve in the internal ear will be found 
described along with the anatomy of that organ in a subsequent page. 
Fig. 494. 
Jiiyular Gangl. 
Strout Gctngl. 
Ty mpanic hr. 
Glos so ~ 
Pharyngeal 
Spinal Accessory 
Pneumo -gas trio 
Nerves of the Eighth Pair, their 
origin, ganglia, and communica- 
tions. 
Ninth Pair. 
The ninth or G-losso-pharyngeal Nerve (Figs. 494, 495), is distributed, as its 
name implies, to the tongue and pharynx, being the nerve of sensation to the 
mucous membrane of the pharynx, fauces, and tonsil, and a special nerve of taste 
in all the parts of the tongue to which it is distributed. It is the smallest of the 
three divisions of the eighth pair of Willis, and arises by three or four filaments 
closely connected together from the upper part of the medulla oblongata in the groove 
between the restiform and the olivary body. 
Its deep origin may be traced through the fasciculi of the lateral tract to a nucleus 
of gray matter at the lower part of the floor of the fourth ventricle, above the nucleus 
of the vagus and below that of the auditory nerve. From its superficial origin it 
passes outward across the flocculus, and leaves the skull at the central part of the 
jugular foramen, in a separate sheath of the dura mater and arachnoid, in front of NINTH PAIR. 
737 
the pneumogastric and spinal accessory nerves (Fig. 415, p. 622). In its passage 
through the jugular foramen it grooves the lower border of the petrous portion of 
the temporal bone, and at its exit from the skull passes forward between the jug- 
ular vein and internal carotid 
artery, and descends in front 
of the latter vessel and beneath 
the styloid process and the mus- 
cles connected with it to the 
lower border of the Stylo-pha- 
ryngeus. The nerve now curves 
inward, forming an arch on the 
side of the neck, and lying upon 
the Stylo-pharyngeus and Mid- 
dle constrictor of the pharynx, 
above the superior laryngeal 
nerve. It then passes beneath 
the Hyo-glossus, and is finally 
distributed to the mucous mem- 
brane of the fauces and base of 
the tongue, the mucous glands 
of the mouth and tonsil. 
In passing through the jug- 
ular foramen the nerve presents, 
in succession, two gangliform en- 
largements. The superior, the 
smaller, is called the jugular 
ganglion; the inferior and 
larger, the petrous ganglion or 
the ganglion of Andersch. 
The superior or jugular 
ganglion is situated in the 
upper part of the groove in 
which the nerve is lodged dur- 
ing its passage through the 
jugular foramen. It is of 
very small size, and involves 
only the outer side of the trunk 
of the nerve, a small fasciculus 
passing beyond it which is not 
connected directly with it. 
The inferior or petrous 
ganglion is situated in a de- 
pression in the lower border of 
the petrous portion of the tem- 
poral bone ; it is larger than the 
former, and involves the whole 
of the fibres of the nerve. 
From this ganglion arise those 
filaments which connect the glos- 
so-pharyngeal with other nerves 
at the base of the skull. 
Its branches of communica- 
tion are with the pneumogastric 
and sympathetic. 
The branches to the pneumogastric are two filaments-one to its auricular 
branch, and one to the upper ganglion of the pneumogastric. 
The branch to the sympathetic is connected with the superior cervical ganglion. 
Fig. 495. 
GIossq -Pharyngeal 
Pneumo -Gastric- 
Sfpinal Accessory., 
Super.Laryngeal 
ExternalLarynjfOtil 
inferior Ji ary ng calf 
=- Cardmo 
vFPttlmonttry 
J 6r«. 
Course and Distribution of the Eighth Pair of Nerves. 738 
CRANIAL NERVES. 
There is also a branch of communication with the facial which perforates the 
posterior belly of the Digastric. It arises from the trunk of the nerve below the 
petrous ganglion, and joins the facial just after its exit from the stylo-mastoid 
foramen. 
The branches of the glosso-pharyngeal nerve are the tympanic, carotid, pharyn- 
geal, muscular, tonsillar, and lingual. 
The tympanic branch. (Jacobson s nerve) arises from the petrous ganglion, and 
enters a small bony canal in the lower surface of the petrous portion of the temporal 
bone, the lower opening of which is situated on the bony ridge which separates the 
carotid canal from the jugular fossa. Jacobson's nerve ascends to the tympanum, 
enters that cavity by an aperture in its floor close to the inner wall, and divides into 
branches which are contained in grooves upon the surface of the promontory, form- 
ing the tympanic plexus. 
Its branches of distribution are-one to the fenestra rotunda, one to the fenestra 
ovalis, and one to the lining membrane of the Eustachian tube and tympanum. 
Its branches of communication are three, and occupy separate grooves on the 
surface of the promontory. One of these arches forward and downward to the 
carotid canal to join the carotid plexus. A second runs forward and upward to 
join the greater superficial petrosal nerve as it lies in the hiatus Fallopii. The 
third branch runs upward through the substance of the petrous portion of the tem- 
poral bone. In its course it passes by the ganglionic enlargement of the facial 
nerve, and, receiving a connecting filament from it, becomes the lesser superficial 
petrosal nerve. This nerve enters the skull through a small aperture situated exter- 
nal to the hiatus Fallopii on the anterior surface of the petrous bone, courses for- 
ward across the base of the skull, and emerges through a foramen in the middle 
fossa (sometimes the foramen ovale) and joins the otic ganglion. 
The carotid branches descend along the trunk of the internal carotid artery 
as far as its point of bifurcation, communicating with the pharyngeal branch of the 
pneumogastric and with the branches of the sympathetic. 
The pharyngeal branches are three or four filaments which unite opposite the 
Middle constrictor of the pharynx with the pharyngeal branches of the pneumogas- 
tric, the external laryngeal, and sympathetic nerves to form the pharyngeal plexus, 
branches from which perforate the muscular coat of the pharynx to supply the mus- 
cles and mucous membrane. 
The muscular branches are distributed to the Stylo-pharyngeus. 
The tonsillar branches supply the tonsil, forming a plexus (circularis tonsil- 
laris) around this body, from which branches are distributed to the soft palate and 
fauces, where they communicate with the palatine nerves. 
The lingual branches are two in number: one supplies the circumvallate papillae 
and the mucous membrane covering the surface of the base of the tongue; the other 
perforates its substance and supplies the mucous membrane and papillae of the side 
of the organ. 
Tenth Pair (Fig. 495, and Fig. 520, p. 787). 
The tenth or Pneumogastric Nerve (nervus vagus or par vagum) has a more 
extensive distribution than any of the other cranial nerves, passing through the neck 
and thorax to the upper part of the abdomen. It is composed of both motor and 
sensory filaments. It supplies the organs of voice and respiration with motor and 
sensory fibres, and the pharynx, oesophagus, stomach, and heart with motor influ- 
ence. Its superficial origin is by eight or ten filaments from the groove between 
the restiform and the olivary body below the glosso-pharyngeal; its deep origin 
may be traced deeply through the fasciculi of the medulla to terminate in a gray 
nucleus near the lower part of the floor of the fourth ventricle. The filaments 
become united and form a flat cord, which passes outward across the flocculus to the 
jugular foramen, through which it emerges from the cranium. In passing through 
this opening the pneumogastric accompanies the spinal accessory, being contained in 
the same sheath of dura mater with it, a membranous septum separating it from the TENTH PAIR. 
739 
glossopharyngeal, which lies in front (Fig. 415, p. 622). The nerve in this situa- 
tion presents a well-marked ganglionic enlargement, which is called ganglion jugu- 
lare, or the ganglion of the root of the pneumogastric: to it the accessory part of 
the spinal accessory nerve is connected. After the exit of the nerve from the 
jugular foramen a second gangliform swelling is formed upon it, called the ganglion 
inferius or the ganglion of the trunk of the nerve; below which it is again joined 
by filaments from the accessory nerve. The nerve passes vertically down the neck 
within the sheath of the carotid vessels lying between the internal carotid artery and 
internal jugular vein as far as the thyroid cartilage, and then between the same vein 
and the common carotid to the root of the neck. Here the course of the nerve 
becomes different on the two sides of the body. 
On the right side the nerve passes across the subclavian artery, between it and 
the subclavian vein, and descends by the side of the trachea to the back part of the 
root of the lung, where it spreads out in a plexiform network (posterior pulmonary), 
from the lower part of which two cords descend upon the oesophagus, on which they 
divide, forming, with branches from the opposite nerve, the oesophageal plexus (plexus 
gulce); below, these branches are collected into a single cord, which runs along the 
back part of the oesophagus, enters the abdomen, and is distributed to the posterior 
surface of the stomach, joining the left side of the solar plexus, and sending filaments 
to the splenic plexus and a considerable branch to the coeliac plexus. 
On the left side the pneumogastric nerve enters the chest between the left carotid 
and subclavian arteries, behind the left innominate vein. It crosses the arch of the 
aorta, and descends behind the root of the left lung and along the anterior surface 
of the oesophagus to the stomach, distributing branches over its anterior surface, 
some extending over the great cul-de-sac, and others along the lesser curvature. 
Filaments from these branches enter the gastro-hepatic omentum and join the left 
hepatic plexus. 
The Ganglion of the Root is of a grayish color, circular in form, about two lines 
in diameter, and resembles the ganglion on the large root of the fifth nerve. 
Connecting branches.-To this ganglion the accessory portion of the spinal 
accessory nerve is connected by several delicate filaments; it also has a communi- 
cating twig with the petrous ganglion of the glosso-pharyngeal, with the facial nerve 
by means of its auricular branch, and with the sympathetic by means of an ascend- 
ing filament from the superior cervical ganglion. 
The G-anglion of the Trunk (inferior) is a plexiform cord, cylindrical in form, of a 
reddish color, and about an inch in length; it involves the whole of the fibres of 
the nerve, and passing over it is the accessory portion of the spinal accessory nerve, 
which blends with the pneumogastric below the ganglion, and is then principally 
continued into its pharyngeal and superior laryngeal branches. 
Connecting branches.-This ganglion is connected with the hypoglossal, the 
superior cervical ganglion of the sympathetic, and the loop between the first and 
second cervical nerves. 
The branches of the pneumogastric are- 
In the jugular fossa Auricular. 
Pharyngeal. 
Superior laryngeal. 
Recurrent laryngeal. 
Cervical cardiac. 
In the neck 
Thoracic cardiac. 
Anterior pulmonary. 
Posterior pulmonary. 
(Esophageal. 
In the thorax 
In the abdomen Gastric. 
The auricular branch (Arnold's) arises from the ganglion of the root, and is 
joined soon after its origin by a filament from the petrous ganglion of the glosso- 
pharyngeal; it passes outward behind the jugulai* vein and enters a small canal on 740 
CRANIAL NERVES. 
the outer wall of the jugular fossa. Traversing the substance of the temporal 
bone, it crosses the aquaeductus Fallopii about two lines above its termination at 
the stylo-mastoid foramen; here it gives off an ascending branch which joins the 
facial, and a descending branch which communicates with the posterior auricular 
branch of the same nerve: the continuation of the nerve reaches the surface by 
passing through the auricular fissure between the mastoid process and the external 
auditory meatus, supplies the integument at the back part of the pinna, and com- 
municates with the branches of the auricularis magnus. 
The pharyngeal branch, the principal motor nerve of the pharynx, arises from 
the upper part of the inferior ganglion of the pneumogastric, receiving a filament 
from the accessory portion of the spinal accessory; it passes across the internal 
carotid artery (in front or behind) to the upper border of the Middle constrictor, 
where it divides into numerous filaments, which communicate with those from the 
glosso-pharyngeal, superior laryngeal (its external branch), and sympathetic to form 
the pharyngeal plexus, from which branches are distributed to the muscles and 
mucous membrane of the pharynx. As this nerve crosses the internal carotid 
some filaments are distributed, together with those from the glosso-pharyngeal, upon 
the wall of this vessel. 
The superior laryngeal is the nerve of sensation to the larynx. It is larger 
than the preceding, and arises from the middle of the inferior ganglion of the pneu- 
mogastric. In its course it receives a branch from the accessory portion of the 
spinal accessory nerve. It descends by the side of the pharynx behind the inter- 
nal carotid, where it divides into two branches, the external and internal laryngeal. 
The external laryngeal branch, the smaller, descends by the side of the larynx, 
beneath the Sterno-thyroid, to supply the Crico-thyroid muscle. It gives branches 
co the pharyngeal plexus and the Inferior constrictor, and communicates with the 
superior cardiac nerve behind the common carotid. 
The internal laryngeal branch descends to the opening in the thyro-hyoid mem- 
brane, through which it passes with the superior laryngeal artery, and is distributed 
to the mucous membrane of the larynx. A small branch enters the Arytenoid mus- 
cle, and another communicates with the recurrent laryngeal nerve. 
The branches to the mucous membrane are distributed, some in front to the 
epiglottis, the base of the tongue, and the epiglottidean glands; while others pass 
backward, in the aryteno-epiglottidean fold, to supply the mucous membrane sur- 
rounding the superior orifice of the larynx, as well as the membrane which lines 
the cavity of the larynx as low down as the vocal chord. 
The filament to the Arytenoid muscle is distributed partly to it and partly to the 
mucous lining of the larynx. 
The filament which joins with the recurrent laryngeal descends beneath the 
mucous membrane on the inner surface of the lateral part of the thyroid cartilage, 
where the two nerves become united. 
The inferior or recurrent laryngeal [Fig. 364, p. 503], so called from its re- 
flected course, is the motor nerve of the larynx. It arises on the right side in front 
of the subclavian artery, winds from before backward round that vessel, and ascends 
obliquely to the side of the trachea behind the common carotid and inferior thyroid 
arteries. On the left side it arises in front of the arch of the aorta, and winds from 
before backward round the aorta at the point where the obliterated remains of the 
ductus arteriosus are connected with it, and then ascends to the side of the trachea. 
The nerves on both sides ascend in the groove between the trachea and oesophagus, 
and, passing under the lower border of the Inferior constrictor muscle, enter the 
larynx behind the articulation of the inferior cornu of the thyroid cartilage with the 
cricoid, being distributed to all the muscles of the larynx excepting the Crico-thy- 
roid, and joining with the superior laryngeal. 
The recurrent laryngeal as it winds round the subclavian artery and aorta gives 
off several cardiac filaments, which unite with the cardiac branches from the pneu- 
mogastric and sympathetic. As it ascends in the neck it gives off oesophageal 
branches, more numerous on the left than on the right side, which supply the ELEVENTH PAIR. 
741 
mucous membrane and muscular coat of the oesophagus; tracheal branches to the 
mucous membrane and muscular fibres of the trachea; and some pharyngeal fila- 
ments to the Inferior constrictor of the pharynx. 
The cervical cardiac branches, two or three in number, arise from the pneu- 
mogastric at the upper and lower part of the neck. 
The superior branches are small, and communicate with the cardiac branches of 
the sympathetic and with the great cardiac plexus. 
The inferior branches, one on each side, arise at the lower part of the neck just 
above the first rib. On the right side this branch passes in front or by the side of 
the arteria innominata, and communicates with one of the cardiac nerves proceeding 
to the deep cardiac plexus. On the left side it passes in front of the arch of the 
aorta and joins the superficial cardiac plexus. 
The thoracic cardiac branches, on the right side, arise from the trunk of the 
pneumogastric as it lies by the side of the trachea, and from its recurrent laryngeal 
branch, but on the left side from the recurrent nerve only; passing inward, they 
terminate in the deep cardiac plexus. 
The anterior pulmonary branches, two or three in number and of small size, 
are distributed on the anterior aspect of the root of the lungs. They join with 
filaments from the sympathetic and form the anterior pulmonary plexus. 
The posterior pulmonary branches, more numerous and larger than the ante- 
rior, are distributed on the posterior aspect of the root of the lung: they are joined 
by filaments from the third and fourth thoracic ganglia of the sympathetic, and form 
the posterior pulmonary plexus. Branches from both plexuses accompany the rami- 
fications of the air-tubes through the substance of the lungs. 
The oesophageal branches are given off from the pneumogastric both above 
and below the pulmonary branches. The lower are more numerous and larger than 
the upper. They form, together with branches from the opposite nerve, the oesoph- 
ageal plexus ov plexus gulce. 
The gastric branches are the terminal filaments of the pneumogastric nerve. 
The nerve on the right side is distributed to the posterior surface of the stomach, 
and joins the left side of the coeliac plexus and the splenic plexus. The nerve on 
the left side is distributed over the anterior surface of the stomach, some filaments 
passing across the great cul-de-sac, and others along the lesser curvature. They 
unite with branches of the right nerve and with the sympathetic, some filaments 
passing through the lesser omentum to the left hepatic plexus. 
Eleventh Pair (Fig. 495). 
The eleventh or Spinal Accessory Nerve [«. e. nervus spinalis ad pneu- 
mogastricum accessorius], consists of two parts-one the accessory part to the 
vagus, and the other the spinal portion. 
The accessory part, the smaller of the two, arises by four or five delicate fila- 
ments from the lateral tract of the cord below the roots of the vagus; these fila- 
ments may be traced to a nucleus of gray matter at the back of the medulla, below 
the origin of the vagus. It joins, in the jugular foramen, with the upper ganglion 
of the vagus by one or two filaments, and is continued into the vagus below the 
second ganglion. It is principally distributed to the pharyngeal and superior 
laryngeal branches of the vagus, but some branches from it are continued into 
the recurrent laryngeal nerve and probably into the cardiac nerves also. 
The spinal portion, firm in texture, arises by several filaments from the lateral 
tract of the cord as low down as the sixth cervical nerve; the fibres pierce the tract, 
and are connected with the anterior horn of the gray matter of the cord. This 
portion of the nerve ascends between the ligamentum denticulatum and the poste- 
rior roots of the spinal nerves, enters the skull through the foramen magnum, and 
is then directed outward to the jugular foramen, through which it passes, lying in 
the same sheath as the pneumogastric, but separated from it by a fold of the arach- 
noid, and is here connected with the accessory portion. At its exit from the jug- 742 
CRANIAL NERVES. 
ular foramen it passes backward, either in front of or behind the internal jugular 
vein, and descends obliquely behind the Digastric and Stylo-hyoid muscles to the 
upper part of the Sterno-mastoid. It pierces that muscle and passes obliquely 
across the occipital triangle, to terminate in the deep surface of the Trapezius. 
This nerve gives several branches to the Sterno-mastoid during its passage through 
it, and joins in its substance with branches from the second cervical which supply 
the muscle. Beneath the Trapezius it joins with the third and fourth cervical 
nerves to form a sort of plexus from which fibres are distributed to the muscle, and 
in the occipital triangle between the two muscles it joins with the second and third 
cervical nerves and assists in the formation of the cervical plexus. [It is accessible 
for operation by incision at either the anterior or posterior border of the Sterno- 
cleido-mastoid muscle at its upper portion.] 
Twelfth Pair (Fig. 496). 
The twelfth or Hypoglossal Nerve is the motor nerve of the tongue. It 
arises by several filaments, from ten to fifteen in number, from the groove between 
Fig. 496. 
N. 
y j\T. 
Glosso-Pharyngonl fa 
Hypoglossal Nerve, Cervical Plexus, and their Branches. 
the pyramidal and olivary bodies, in a continuous line with the anterior roots of the 
spinal nerves. The deep origin of the nerve can be traced through the olivary 
body to a special nucleus at the lowest point of the fourth ventricle, close to the 
decussation of the pyramids. The filaments of this nerve are collected into two TWELFTH PAIR. 
743 
bundles, which perforate the dura mater separately, opposite the anterior condyloid 
foramen, and unite together after their passage through it. In those cases in which 
the anterior condyloid foramen in the occipital bone is double, these two portions of 
the nerve are separated by the small piece of bone which divides the foramen. The 
nerve descends almost vertically to a point corresponding with the angle of the jaw. 
It is at first deeply seated beneath the internal carotid artery and internal jugular 
vein, and intimately connected with the pneumogastric nerve; it then passes for- 
ward between the vein and artery, and lower down in the neck becomes superficial 
below the Digastric muscle. The nerve then loops round the occipital artery, and 
crosses the externa] carotid below the tendon of the Digastric muscle. It passes 
beneath the Stylo-hyoid muscle, lying between it and the Hyo-glossus, and commu- 
nicates at the anterior border of the latter muscle with the gustatory nerve; it is 
then continued forward in the fibres of the Genio-hyo-glossus muscle as far as the 
tip of the tongue, distributing branches to its substance. 
Branches of this nerve communicate with the 
Pneumogastric. 
Sympathetic. 
First and second cervical nerves. 
Gustatory. 
The communication with the pneumogastric takes place close to the exit of the 
nerve from the skull, numerous filaments passing between the hypoglossal and 
lower ganglion of the pneumogastric; sometimes the two nerves are united so as 
to form one mass. 
The communication with the sympathetic takes place opposite the atlas by 
branches derived from the superior cervical ganglion, and in the same situation 
the nerve is joined by a filament derived from the loop connecting the first two 
cervical nerves. 
The communication with the gustatory takes place near the anterior border of 
the Hyo-glossus muscle by numerous filaments which ascend upon it. 
The branches of distribution are the 
Descendens noni. 
Muscular. 
Thyro-hyoid. 
Meningeal. 
The descendens noni [/. e. descending branch of the ninth nerve-a relic of 
the older enumeration of Willis] is a long slender branch which quits the hypo- 
glossal where it turns round the occipital artery. It descends obliquely across the 
sheath of the carotid vessels, and joins the communicating branches from the second 
and third cervical nerves just below the middle of the neck to form a loop. From 
the convexity of this loop branches pass forward to supply the Sterno-hyoid, Sterno- 
thyroid, and both bellies of the Omo-hyoid. According to Arnold, another filament 
descends in front of the vessels into the chest and joins the cardiac and phrenic 
nerves. The descendens noni is occasionally contained in the sheath of the carotid 
vessels, being sometimes placed over and sometimes beneath the internal jugular 
vein. 
The thyro-hyoid is a small branch arising from the hypoglossal near the pos- 
terior border of the Hyo-glossus; it passes obliquely across the great cornu of the 
hyoid bone and supplies the Thyro-hyoid muscle. 
The muscular branches are distributed to the Stylo-glossus, Hyo-glossus, 
Genio-hyoid, and Genio-hyo-glossus muscles. At the under surface of the tongue 
numerous slender branches pass upward into the substance of the organ. 
Meningeal Branches.-As the hypoglossal nerve passes through the anterior 
condyloid foramen it gives off, according to Luschka, several filaments to the dura 
mater in the posterior fossa of the base of the skull. The Spinal Nerves. 
THE Spinal Nerves [*] are so called because they take their origin from the 
spinal cord and are transmitted through the intervertebral foramina on 
either side of the spinal column. There are thirty-one pairs of spinal nerves, 
which are arranged into the following groups, corresponding to the region of the 
spine through which they pass: 
Cervical 8 pairs. 
Dorsal . . • • . 12 " 
Lumbar . . . • • 5 " 
Sacral . . . . . 5 " 
Coccygeal ..... 1 pair. 
It will be observed that each group of nerves corresponds in number with the 
vertebrae in that region, except the cervical and coccygeal. 
Each spinal nerve arises by two roots, an anterior or motor root, and a posterior 
or sensory root. 
Roots of the Spinal Nerves. 
The anterior roots arise somewhat irregularly from a linear series of depres- 
sions on the antero-lateral column of the spinal cord, gradually approaching toward 
the anterior median fissure as they descend. 
The fibres of the anterior roots, according to the researches of Dr. Lockhart 
Clarke, are attached to the anterior part of the antero-lateral column, and, after 
penetrating horizontally through the longitudinal fibres of this tract, enter the gray 
substance, where their fibrils cross each other and diverge in all directions like the 
expanded hairs of a brush, some of them running more or less longitudinally 
upward and downward, and others decussating with those of the opposite side 
through the anterior commissure in front of the central canal. Kblliker states 
© 
that many fibres of the anterior root enter the lateral column of the same side, 
where, turning upward, they pursue their course as longitudinal fibres. In other 
respects the description of the origin of the anterior roots by these observers is 
very similar. 
The posterior roots are all attached to the cord at the postero-lateral fissure. 
They enter the gray substance of the posterior cornu, either directly through the 
substantia gelatinosa, or indirectly by first passing through the white matter of the 
posterior column and winding round in front of the caput cornu. Those which 
enter the gray matter at once for the most part turn upward and downward, and 
become continuous with the fine nerve-plexus in the central portion of the gray 
matter; some few fibres pass transversely through the posterior commissure to the 
opposite side, and others into the anterior cornu of the same side. Those fibres 
which enter the gray matter in front of the caput cornu reach the posterior vesic- 
ular column and blend with it, a few fibres passing through it to become longi- 
tudinal in the posterior column of the cord. 
The posterior roots of the nerves are larger, but the individual filaments are 
finer and more delicate, than those of the anterior. As their component fibrils pass 
outward toward the aperture in the dura mater they coalesce into two bundles, 
[' Since the section on the Histology of the Nerves was printed I have received the second edi- 
tion of the JBradshawe Lecture for 1883, by Mr. John Marshall. In the original lecture he predicted 
that besides the vaso-motor (sympathetic) nerves distributed to the blood-vessels of the nerves, there 
would be found sensory nervi. nervorum. In the second edition this prediction is verified, and he gives 
several excellent drawings by Prof. Victor Horsley demonstrating their existence.] 
744 DIVISIONS OF THE SPINAL NERVES. 
745 
receive a tubular sheath from that membrane, and enter the ganglion which is 
developed upon each root. 
The posterior root of the first cervical nerve forms an exception to these charac- 
teristic. It is smaller than the anterior, has frequently no ganglion developed upon 
it, and when the ganglion exists it is often situated within the dura mater. 
The anterior roots are the smaller of the two, devoid of any ganglionic enlarge- 
ment, and their component fibrils are collected into two bundles near the interver- 
tebral foramina. 
Ganglia of the Spinal Nerves. 
A gang-lion is developed upon the posterior root of each of the spinal nerves. 
These ganglia are of an oval form and of a reddish color; they bear a proportion 
in size to the nerves upon which they are formed, and are placed in the interver- 
tebral foramina external to the point where the nerves perforate the dura mater. 
Each ganglion is bifid internally where it is joined by the two bundles of the pos- 
terior root, the two portions being united into a single mass externally. The gan- 
glion upon the first and second cervical nerves forms an exception to these charac- 
teristic, being placed on the arches of the vertebra over which the nerves pass. 
The ganglia also of the sacral nerves are placed within the spinal canal, and that on 
the coccygeal nerve also in the canal about the middle of its posterior root. 
[Divisions of the Spinal Nerves.] 
Immediately beyond the ganglion the two roots coalesce, their fibres intermingle, 
and the trunk thus formed passes out of the intervertebral foramen, and divides 
into an anterior division1 for the supply of the anterior part of the body, and a 
posterior division for the posterior part, each containing fibres from both roots. 
Anterior Divisions of the Spinal Nerves. 
The anterior divisions of the spinal nerves supply the parts of the body in 
front of the spine, including the limbs. They are for the most part larger than tlm 
posterior divisions, this increase of size being proportioned to the larger extent of 
structures they are required to supply. Each division is connected by slender fila- 
ments with the sympathetic. In the dorsal region the anterior divisions of the 
spinal nerves are completely separate from each other and are uniform in their 
distribution, but in the cervical, lumbar, and sacral regions they form intricate 
plexuses previous to their distribution. 
Posterior Divisions of the Spinal Nerves 
The posterior divisions of the spinal nerves are generally smaller than the 
anterior; they arise from the trunk resulting from the union of the roots in the 
intervertebral foramina, and, passing backward, divide into external and internal 
branches, which are distributed to the muscles and integument behind the spine. The 
first cervical and lower sacral nerves are exceptions to these characteristics. 
[Points of Origin and Emergence of the Spinal Nerves. 
The roots of the spinal nerves, as soon as they leave the spinal cord, run 
obliquely downward to the intervertebral foramina, through which they pass. 
The obliquity of their course increases from above downward, especially in the 
lower nerves. Hence their points of emergence from the spinal cord and their 
points of emergence from the spinal column are not at the same level. It is often 
important to know the relation of these points of origin from the spinal cord, and 
1 For the sake of clearness I have thought it better to call the primary branches into which the 
compound nerve divides, " divisions," instead of " branches," as in the former editions. 746 
THE SPINAL NERVES. 
[Fig. 497. 
1 c 
MOTOR. 
SENSORY. 
REFLEX. 
2 
St. Mastoid. 
3 
4 
5 
■ 
Trapezius. 
| Diaphragm. 
Neck and Scalp. 
Neck and Shoulder. 
Serratus. 
6 
7 
Shoulder. ~| 
Shoulder. 
- Scapular. 
Arm. 1 mus. 
Arm. 
8 
- 
Hand. 
Hand. 
ID 
(ulnar lowest.) 
2 
4 
Front of Thorax. 
5 
Intercostal 
■ Epigastric. 
6 
Muscles. 
• Ensiform area. 
7 
■ 
8 
9 
Abdominal 
J 
Abdomen 
(Umbilicus 10th). 
10 
Muscles. 
- Abdominal. 
11 
1 Buttock, upper 
12 
- 
j part. 
1 L 
■ 
Groin and Scrotum 
2 
- 
J 
'lexors, hip. 
(front). 
f outer side. 
• Cremasteric. 
3 
Extensors, knee. 
1 
Thigh -j front. 
j- Knee-jerk. 
> Adductors. 
1 
4 
J 
L inner side. 
5 
Abductors. 
hip. 
■ 
I 
jeg inner side. 
Buttock, lower 
- Gluteal. 
1 S 
2 
4 
I 
Extensors (?) - 
Flexors, knee ( 
- Muscles of leg 
moving foot. 
'erineal and J 
Muscles. 
?) 
Inal 
I 
part. 
Back of Thigh. 
Leg ) except 
and > inner 
Foot) part. 
'erineum and 
Anus. 
Foot-clonus. 
Plantar. 
5 
Skin from Coccvx 
Co 
to Anus. 
C 1- 
2 ■ 
3- 
4" 
5' 
6- 
7- 
D 1- 
2- 
3- 
4- 
5- 
6- 
7- 
8- 
9- 
10- 
11- 
12- 
L 1- 
2- 
3 
4 
5 
S • 
Co- 
Diagram and Table showing the Approximate Relation of the Spinal Nerves of the Various Motor, Sensory, and 
Reflex Functions of the Spinal Cord. (From anatomical and pathological data. From Gowers.)] 
of emergence through the intervertebral foramina to the spinous processes of the 
vertebrae. Fig. 497 illustrates this, as well as the motor, sensory, and reflex func- 
tions of the various spinal nerves.] 
CERVICAL NERVES. 
The roots of the cervical nerves increase in size from the first to the fifth; 
and then remain the same size to the eighth. The posterior roots bear a propor- 
tion to the anterior as 3 to 1, which is much greater than in any other region, the 
individual filaments being also much larger than those of the anterior roots. In POSTERIOR DIVISIONS OF THE CERVICAL NERVES. 
747 
direction the roots of the cervical are less oblique than those of the other spinal 
nerves. The first cervical nerve is directed a little upward and outward; the 
second is horizontal; the others are directed obliquely downward and outward, the 
lowest being the most oblique, and consequently longer than the upper, the distance 
between their place of origin and their point of exit from the spinal canal never 
exceeding the depth of one vertebrae. 
The trunk of the first cervical nerve (suboccipital ) leaves the spinal canal between 
the occipital bone and the posterior arch of the atlas, the second, between the poste- 
rior arch of the atlas and the lamina of the axis; and the eighth (the last), between 
the last cervical and first dorsal vertebrae. 
Each nerve at its exit from the intervertebral foramen divides into an anterior 
and a posterior division. The anterior divisions of the four upper cervical nerves 
form the cervical plexus. The anterior divisions of the four lower cervical nerves, 
together with the first dorsal, form the brachial plexus. 
Posterior Divisions of the Cervical Nerves (Fig. 498). 
The posterior division of the first cervical (suboccipital) nerve differs from 
the posterior divisions of the other cervical nerves in not dividing into an external 
and internal branch. It is larger than the anterior, and escapes from the spinal 
canal between the occipital bone and the posterior arch of the atlas lying behind 
the vertebral artery. It enters the suboccipital triangle formed by the Rectus 
capitis posticus major, the Obliquus superior, and Obliquus inferior, and supplies 
the Recti and Obliqui muscles and the Complexus. From the branch which sup- 
plies the Inferior oblique a filament is given off which joins the second cervical 
nerve. This nerve also occasionally gives off a cutaneous filament, which accom- 
panies the occipital artery and communicates with the occipitalis major and minor 
nerves. 
The posterior division of the second cervical nerve is three or four times 
greater than the anterior branch, and the largest of all the posterior cervical divis- 
ions. It emerges from the spinal canal between the posterior arch of the atlas and 
lamina of the axis, below the Inferior oblique. It supplies this muscle and receives 
a communicating filament from the first cervical. It then divides into an external 
and an internal branch. 
The internal branch, called, from its size and distribution, the occipitalis major 
[Fig. 493, p. 734], ascends obliquely inward between the Obliquus inferior and Com- 
plexus, and pierces the latter muscle and the Trapezius near their attachments to the 
cranium. It is now joined by a filament from the third cervical nerve, and, ascend- 
ing on the back part of the head with the occipital artery, divides into two branches, 
which supply the integument of the scalp as far forward as the vertex, communicat- 
ing with the occipitalis minor. It gives off an auricular branch to the back part of 
the ear, and muscular branches to the Complexus. The external branch is often 
joined by the external branch of the posterior division of the third, and supplies 
the Complexus, Splenius, and Trachelo-mastoid. 
The posterior division of the third cervical is smaller than the preceding, but 
larger than the fourth ; it differs from the posterior divisions of the other cervical 
nerves in its supplying an additional filament to the integument of the occiput. 
'This occipital branch arises from the internal or cutaneous branch beneath the 
Trapezius; it pierces that muscle, and supplies the skin on the lower and back 
part of the head. It lies to the inner side of the occipitalis major, with which it 
is connected. The posterior division of the third nerve, like the others, divides 
into an external and internal branch. The internal branch passes between the 
Semispinalis and Complexus, and, piercing the Splenius and Trapezius, supplies 
the skin over the latter muscle; the external branch joins with that of the poste- 
rior division of the second to supply the Splenius, Complexus, and Trachelo- 
mastoid. 748 
THE SPINAL NERVES. 
The posterior division of the suboccipital nerve and the internal branches of the 
posterior divisions of the second and third cervical nerves are occasionally joined 
beneath the Complexus by communicating branches. This communication is described 
by Cruveilhier as the posterior cervical plexus. 
The posterior divisions of the fourth, fifth, sixth, seventh, and eighth cer- 
vical nerves (Fig. 507, p. 765) pass backward and divide behind the posterior 
Intertransverse muscles into external and internal branches. The external branches 
Fig. 498. 
Posterior Divisions of the Upper Cervical Nerves. 
supply the muscles at the side of the neck-viz. the Cervicalis ascendens, Transver- 
sals colli, and Trachelo-mastoid. The internal branches, the larger, are distributed 
differently in the upper and lower part of the neck. Those derived from the fourth 
and fifth nerves pass between the Semispinalis and Complexus muscles, and, having 
reached the spinous processes, perforate the aponeurosis of the Splenius and Trape- 
zius, and are continued outward to the integument over the Trapezius, whilst those 
derived from the three lowest cervical nerves are the smallest, and are placed beneath 
the Semispinalis, which they supply, and then pass inw the Interspinalis, Multifidus ANTERIOR DIVISIONS OF THE CERVICAL NERVES. 
749 
spinae, and Complexus, and send twigs through this latter muscle to supply the integ- 
ument near the spinous processes (Hirschfeld).1 
Anterior Divisions oe the Cervical Nerves. 
The anterior division of the first or suboccipital nerve is of small size. It 
escapes from the spinal canal through a groove upon the posterior arch of the atlas. 
In this groove it lies beneath the vertebral artery, to the inner side of the Rectus 
capitis lateralis. As it crosses the foramen in the transverse process of the atlas it 
receives a filament from the sympathetic. It then descends, in front of this process, 
to communicate with an ascending branch from the second cervical nerve. 
Communicating filaments from this nerve join the pneumogastric, the hypo- 
glossal, and the sympathetic, and some branches are distributed to the Rectus lat- 
eralis and the two Anterior recti. According to Valentin, the anterior division of 
the suboccipital also distributes filaments to the occipito-atloid articulation and mas- 
toid process of the temporal bone. 
The anterior division of the second cervical nerve escapes from the spinal 
canal between the posterior arch of the atlas and the lamina of the axis, and, pass- 
ing forward on the outer side of the vertebral artery, divides in front of the Inter- 
transverse muscle into an ascending branch, which joins the first cervical,-and one 
or two descending branches, which join the third. It gives off the small occipital; 
a branch to assist in forming the great auricular; another to assist in forming the 
superficial cervical; one of the communicantes noni; and a filament to the Sterno- 
mastoid which communicates in the substance of the muscle with the spinal accessory. 
The anterior division of the third cervical nerve is double the size of the 
preceding. At its exit from the intervertebral foramen it passes downward and 
outward beneath the Sterno-mastoid, and divides into two branches. The ascend- 
ing branch joins the anterior division of the second cervical; the descending 
branch passes down in front of the Scalenus anticus and communicates with the 
fourth. It gives off the greater part of the great auricular and superficial cervical 
nerves; one of the communicantes noni; a branch to the supraclavicular nerves; a 
filament to assist in forming the phrenic and muscular branches to the Levator 
anguli scapulae and Trapezius: this latter nerve communicates beneath the muscle 
with the spinal accessory. Sometimes the nerve to the Scalenus medius is derived 
from this source. 
The anterior division of the fourth cervical is of the same size as the pre- 
ceding. It receives a branch from the third, sends a communicating branch to the 
fifth cervical, and, passing downward and outward, divides into numerous filaments 
which cross the posterior triangle of the neck, forming the supraclavicular nerves. 
It gives a branch to the phrenic nerve, whilst it is contained in the intertransverse 
space, and sometimes a branch to the Scalenus medius muscle. It also gives a 
branch to the Levator anguli scapulae and to the Trapezius which unites with the 
branch given off from the third nerve and communicates beneath the muscle with 
the spinal accessory. 
The anterior divisions of the fifth, sixth, seventh, and eighth cervical 
nerves are remarkable for their large size. They are much larger than the pre- 
ceding nerves, and are all of equal size. They assist in the formation of the 
brachial plexus. 
Cervical Plexus. 
The Cervical Plexus (Fig. 499, p. 751) is formed by the anterior divisions of the 
four upper cervical nerves. It is situated opposite the four upper vertebrae, resting 
1 It will be seen that this statement, made on the authority of Hirschfeld, differs from that con- 
tained in the last edition of this work and in many of the textbooks on anatomy, where it is stated 
that the posterior divisions of the three lowest cervical nerves do not furnish any cutaneous fila- 
ments. The subject has been carefully investigated by my friend Mr. Ross, demonstrator of anatomy 
at St. George's Hospital, who informs me that he has been able to demonstrate the existence of cuta- 
neous filaments from each of the three lowest cervical nerves. 750 
THE SPINAL NERVES. 
upon the Levator anguli scapulae and Scalenus medius muscles and covered in by 
the Sterno-mastoid. 
Its branches may be divided into two groups, superficial and deep, which may 
be thus arranged: 
Ascending 
Superficialis colli. 
Auricularis magnus. 
Occipitalis minor. 
Superficial 
Sternal. 
Clavicular. 
Acromial. 
Descending Supraclavicular 
Communicating. 
Muscular. 
Communicans noni. 
Phrenic. 
Internal 
Deep. . . 
Communicatin o-. 
o 
Muscular. 
External 
Superficial Branches of the Cervical Plexus (Fig. 499, p. 751; Fig. 490, 
p. 731; Fig. 493, p. 734; and Fig. 507, p. 765). 
The Superficialis colli arises from the second and third cervical nerves, turns 
round the posterior border of the Sterno-mastoid about its middle, and, passing 
obliquely forward beneath the external jugular vein to the anterior border of that 
muscle, perforates the deep cervical fascia, and divides beneath the Platysma into 
two branches, which are distributed to the antero-lateral parts of the neck. 
The ascending branch gives a filament which accompanies the external jugular 
vein; it then passes upward to the submaxillary region and divides into branches, 
some of which form a plexus with the cervical branches of the facial nerve beneath 
the Platysma; others pierce that muscle, supply it, and are distributed to the integ- 
ument of the upper half of the neck, at its fore part, as high as the chin. 
The descending branch (occasionally represented by two or more filaments) 
pierces the Platysma, and is distributed to the integument of the side and front 
of the neck as low as the sternum. 
The Auricularis magnus is the largest of the ascending branches. It arises 
from the second and third cervical nerves, winds round the posterior border of the 
Sterno-mastoid, and after perforating the deep fascia ascends upon that muscle 
beneath the Platysma to the parotid gland, where it divides into numerous 
branches. 
The facial branches pass across the parotid, and are distributed to the integu- 
ment of the face; others penetrate the substance of the gland and communicate 
with the facial nerve. 
The posterior or auricular branches ascend to supply the integument of the 
back part of the pinna, communicating with the auricular branches of the facial 
and pneumogastric nerves. 
The mastoid branch j oins the posterior auricular branch of the facial, and, cross- 
ing the mastoid process, is distributed to the integument behind the ear. 
The Occipitalis minor arises from the second cervical nerve; it curves round 
the posterior border of the Sterno-mastoid above the preceding, and is directed 
almost vertically along the posterior border of that muscle to the back part of the 
side of the head. Near the cranium it perforates the deep fascia, and is continued 
upward along the side of the head behind the ear, supplying the integument and 
Occipito-frontalis muscle, and communicating with the occipitalis major, auricularis 
magnus, and posterior auricular branch of the facial. 
This nerve gives off an auricular branch which supplies the Attolens aurem 
and the integument of the upper and back part of the auricle, communicating with 
the mastoid branch of the auricularis magnus. This branch is occasionally derived DEEP BRANCHES OF THE CERVICAL PLEXUS. 
751 
from the great occipital nerve. The occipitalis minor varies in size ; it is occasion- 
ally double. 
The Descending or Supraclavicular branches arise from the third and fourth 
cervical nerves: emerging beneath the posterior border of the Sterno-mastoid, they 
descend in the interval between that muscle and the Trapezius, and divide into 
branches which are arranged, according to their position, into three groups. 
RECT. CAP . LAT. 
Fig. 499. 
I 
II 
nr 
w 
RECT. ANT . MAJOR 
j RECT. ANT. MINOR 
TO SYMPATHETIC 
1T0 HYPOGLOSSAL 
TO VAGUJ 
TO SCALPS OCCIPITO FRONTALIS 
3 TO AURICLE 8< ATTOLENS AUREM 
5TERNO-MASTOID 
C. WITH SPIN. 
IMASTOID 
AURICULAR 
> FACIAL 
>CUMMUN1CANS NONI 
?LEV. ANG. SCAP. 
.TRAPEZIUS 
G. WITH SPIN. ACCESSORY 
7STERNAL 
ACROMIAL 
PHRENIC 
SCALEN. MEDIUS 
Plan of the Cervical Plexus. 
The inner or sternal branch crosses obliquely over the clavicular and sternal 
attachments of the Sterno-mastoid, and supplies the integument as far as the 
median line. 
The middle or clavicular branch crosses the clavicle, and supplies the integument 
over the Pectoral and Deltoid muscles, communicating with the cutaneous branches 
of the upper intercostal nerves. The clavicular branch has been known to pass 
through a foramen in the clavicle at the junction of the outer with the middle 
third of the bone. 
The external or acromial branch passes obliquely across the outer surface of the 
Trapezius and the acromion, and supplies the integument of the upper and back 
part of the shoulder. 
Deep Branches of the Cervical Plexus, Internal Series. 
The communicating branches consist of several filaments which pass from the 
loop between the first and second cervical nerves in front of the atlas to the pneu- 752 
THE SPINAL NERVES. 
mogastric, hypoglossal, and sympathetic, and a communicating branch between the 
fourth and fifth cervical. 
Muscular branches supply the Anterior recti and Rectus lateralis muscles; 
they proceed from the first cervical nerve and from the loop formed between it and 
the second. 
The Communicans noni (Fig. 496, p. 742) consists usually of two filaments, 
one being derived from the second, and the other from the third cervical. These 
filaments pass downward on the outer side of the internal jugular vein, cross in 
front of the vein a little below the middle of the neck, and form a loop with the 
descendens noni in front of the sheath of the carotid vessels. Occasionally the 
junction of these nerves takes place within the sheath. 
The Phrenic Nerve (internal respiratory of Bell) [the motor nerve of the Dia- 
phragm] arises from the third and fourth cervical nerves, and receives a communi- 
cating branch from the fifth, or sometimes from the fifth and sixth. It descends to 
the root of the neck, lying obliquely across the front of the Scalenus anticus, passes 
over the first part of the subclavian artery, between it and the subclavian vein, and, 
as it enters the chest, crosses the internal mammary artery near its origin. Within 
the chest it descends nearly vertically in front of the root of the lung and by the 
side of the pericardium, between it and the mediastinal portion of the pleura, to the 
Diaphragm, where it divides into branches which separately pierce that muscle and 
are distributed to its under surface. 
The two phrenic nerves differ in their length, and also in their relations at the 
upper part of the thorax. 
The right nerve is situated more deeply, and is shorter and more vertical in 
direction, than the left; it lies on the outer side of the right vena innominata and 
superior vena cava. 
The left nerve is rather longer than the right, from the inclination of the heart 
to the left side and from the Diaphragm being lower on this than on the opposite 
side. At the upper part of the thorax it crosses in front of the arch of the aorta 
to the root of the lung. 
Each nerve supplies filaments to the pericardium and pleura, and near the chest 
is joined by a filament from the sympathetic, and occasionally by one from the 
union of the descendens noni with the spinal nerves: this filament is found, accord- 
ing to Swan, only on the left side. It is also usually connected by a filament with 
the nerve to the Subclavius muscle. Branches have been described as passing to 
the peritoneum. 
From the right nerve one or two filaments pass to join in a small ganglion with 
phrenic branches of the solar plexus, and branches from this ganglion are distrib- 
uted to the hepatic plexus, the suprarenal capsule, and inferior vena cava. From 
the left nerve filaments pass to join the phrenic plexus of the sympathetic, but 
without any ganglionic enlargement. 
Deep Branches of the Cervical Plexus, External Series. 
Communicating- Branches.-The cervical plexus communicates with the spinal 
accessory nerve in the substance of the Sterno-mastoid muscle, in the occipital trian- 
gle, and beneath the Trapezius. 
Muscular branches are distributed to the Sterno-mastoid, Levator anguli scap- 
ulae, Scalenus medius, and Trapezius. 
The branch for the Sterno-mastoid is derived from the second cervical, the Leva- 
tor anguli scapulae receiving branches from the third and the Trapezius branches 
from the third and fourth. The Scalenus medius is supplied sometimes from the 
third, sometimes the fourth, and occasionally from both nerves. 
The Brachial Plexus (Fig. 500). 
The Brachial Plexus is formed by the union of the anterior branches of the 
four lower cervical and the greater part of the first dorsal nerves. It extends from THE BRACHIAL PLEXUS. 
753 
the lower part of the side of the neck to the axilla. It is very broad and presents 
little of a plexiform arrangement at its commencement, is narrow opposite the clav- 
icle, becomes broad, and forms a more dense interlacement in the axilla, and divides 
opposite the coracoid process into numerous branches for the supply of the upper 
FROM 4 - 
Fig. 500. 
3 RHOMBOID 
SUB-CLAV I AN 
SUPRA-SCAPULAR 
c. WITH PHr/i/c S 
BRS TO LONG/ 
US COLL) A. V 
SCALENI 
JEXT: ANT: THORACIC 
UPPER SUB-SCAPULAR. 
SUB-SCAPULAR 
|S1 dorsal 
CIRCUMFLEX 
POSTERIOR THORACIC 
internal, cutaneous 
ilesser internal, cutaneous 
INT. ANT. THORACIC 
MUSCULO-CUTANEOUS 
MUSCULO-SPIRAL 
I ULNAR 
l MEDIAN 
Plan of the Brachial Plexus. 
limb. The nerves which form the plexus are all similar in size, and their mode 
of communication is subject to considerable variation, so that no one plan can be 
given as applying to every case. The following appears, however, to be the most 
constant arrangement: The fifth and sixth cervical unite together soon after their 
exit from the intervertebral foramina to form a common trunk. The eighth cervical 
and first dorsal also unite to form one trunk. So that the nerves forming the plexus, 
as thev lie on the Scalenus medius external to the outer border of the Scalenus anti- 
cus are blended into three trunks-an outer one, formed by the junction of the fifth 
and sixth cervical nerves; a middle one, consisting of the seventh cervical nerve; 
and an inner one, formed by the junction of the eighth cervical and first dorsal 
nerves. As they pass beneath the clavicle each of these three trunks divides into 
two branches, an anterior and a posterior. The anterior divisions of the outer and 
middle trunks then unite to form a common cord, which is situated on the outer side 
of the middle part of the axillary artery, and is called the outer cord of the brachial 
plexus. The anterior division of the inner trunk, formed by the union of the eighth 
cervical and first dorsal, courses down on the inner side of the axillary artery in the 
middle of the axilla, and forms the inner cord of the brachial plexus. The posterior 
cords of the outer trunk (formed by the junction of the fifth and sixth nerves) and 
of the middle trunk (the seventh nerve) unite together to form the posterior cord 754 
THE SPINAL NERVES. 
of the brachial plexus, which is situated behind the second portion of the axillary 
artery. From this posterior trunk are given off the two lower subscapular nerves, 
the upper subscapular nerve being given off from the posterior division of the outer 
trunk prior to its junction with the posterior division of the middle trunk. The pos- 
terior trunk divides into the circumflex and musculo-spiral nerves ; and the latter of 
these two nerves is subsequently joined by the posterior division of the inner trunk, 
formed by the union of the eighth cervical and first dorsal.1 
The brachial plexus communicates with the cervical plexus by a branch from 
the fourth to the fifth nerve, and with the phrenic nerve by a branch from the fifth 
cervical, which j oins that nerve on the Anterior scalenus muscle: the cervical and 
first dorsal nerves are also joined by filaments from the middle and inferior cervical 
ganglia of the sympathetic close to their exit from the intervertebral foramina. 
Relations.-In the neck the brachial plexus lies at first between the Anterior 
and Middle scaleni muscles, and then above and to the outer side of the subclavian 
artery. [At this point it is accessible for operations, such as stretching or resec- 
tion.] It then passes behind the clavicle and Subclavius muscle, lying upon the 
first serration of the Serratus magnus and the Subscapularis muscles. In the axilla 
it is placed on the outer side of the first portion of the axillary artery; it surrounds 
the artery in the second part of its course, one cord lying upon the outer side of that 
vessel, one on the inner side, and one behind it; and at the lower part of the axil- 
lary space gives off its terminal branches to the upper extremity. 
Branches.-The branches of the brachial plexus are arranged into two groups- 
viz. those given off above the clavicle, and those below that bone. 
Branches above the Clavicle. 
Communicating. 
Muscular. 
Posterior thoracic. 
Suprascapular. 
The communicating' branch with the phrenic is derived from the fifth cervical 
nerve or from the loop between the fifth and sixth; it joins the phrenic on the Ante- 
rior scalenus muscle. 
The muscular branches supply the Longus colli, Scaleni, Rhomboidei, and 
Subclavius muscles. Those for the Scaleni and Longus colli arise from the lower 
cervical nerves at their exit from the intervertebral foramina. The rhomboid 
branch arises from the fifth cervical, pierces the Scalenus medius, and passes 
beneath the Levator anguli scapulae, which it occasionally supplies, to the Rhom- 
boid muscles. The nerve to the Subclavius is a small filament which arises from 
the fifth cervical at its point of junction with the sixth nerve; it descends in front 
of the subclavian artery to the Subclavius muscle, and is usually connected by a 
filament with the phrenic nerve. 
The posterior thoracic nerve (long thoracic, external respiratory of Bell} (Fig. 
505, p. 760) supplies the Serratus magnus, and is remarkable for the length of its 
course. It sometimes arises by two roots from the fifth and sixth cervical nerves 
immediately after their exit from the intervertebral foramina, but generally by three 
roots from the fifth, sixth, and seventh nerves. These unite in the substance of 
the Middle scalenus muscle, and after emerging from it the nerve passes down 
1 It will be noticed that this description varies from that in- previous editions, which was the 
formerly-accepted description of the plexus. The investigations of anatomists, and especially of 
Mr. Clement Lucas, have proved, however, that this description was not strictly correct, and the 
account given above substantially agrees with that of Mr. Lucas, as well as with that of Henle, the 
main point of difference being that the posterior division of the inner trunk-which, by the way, is 
an inconsiderable fasciculus in point of size-does not assist in forming the posterior corn of the 
plexus, but is entirely concerned in forming the musculo-spiral nerve. This I have found in my 
investigation to be the more constant arrangement of the two. The student must not expect, how- 
ever, to find in every instance an exact counterpart of the above description, since the plexus is sub- 
ject in its formation to the greatest diversities, and there is no doubt that an ingenious dissector, by 
splitting the nerves, may make almost any complicated arrangement which may suit his fancy. (See 
Mr. Lucas's paper in the Guy's Hospital Reports, 1875.) [See also a paper founded on an elaborate 
series of dissections by Dr. J. F. Walsh, zlwier. Journal Med. Sd., 1877.] BRANCHES BELOW THE CLAVICLE. 
755 
behind the brachial plexus and the axillary vessels, resting on the outer surface 
of the Serratus magnus. It extends along the side of the chest to the lower 
border of that muscle, and supplies it with numerous filaments. 
The suprascapular nerve (Fig. 506, p. 762) arises from the cord formed by the 
fifth and sixth cervical nerves; passing obliquely outward beneath the Trapezius, it 
enters the supraspinous fossa through the notch in the upper border of the scapula, 
and, passing beneath the Supraspinatus muscle, curves in front of the spine of the 
scapula to the infraspinous fossa. In the supraspinous fossa it gives off two branches 
to the Supraspinatus muscle and an articular filament to the shoulder-joint; and in 
the infraspinous fossa it gives off two branches to the Infraspinatus muscle, besides 
some filaments to the shoulder-joint and scapula. 
Branches below the Clavicle. 
To the chest Anterior thoracic. 
To the shoulder 
Subscapular. 
Circumflex. 
' Musculo-cutaneous. 
Internal cutaneous. 
Lesser internal cutaneous. 
Median. 
Ulnar. 
Musculo-spiral. 
To the arm, forearm, and hand 
The branches given off below the clavicle are derived from the three cords of 
the brachial plexus in the following manner: 
From the outer cord arise the external of the two anterior thoracic nerves, the 
musculo-cutaneous nerve, and the outer head of the median. 
From the inner cord arise the internal of the two anterior thoracic nerves, the 
internal cutaneous, the lesser internal cutaneous (nerve of Wrisberg), the ulnar, and 
inner head of the median. 
From the posterior cord arise two of the three subscapular nerves, the third 
arising from the posterior division of the trunk formed by the fifth and sixth cervi- 
cal nerves: the cord then divides into the musculo-spiral and circumflex nerves. 
The Anterior Thoracic Nerves (Fig. 505, p. 760), two in number, supply the 
Pectoral muscles. 
The external or superficial branch, the larger of the two, arises from the outer 
cord of the brachial plexus, through which its fibres may be traced to the fifth, 
sixth, and seventh cervical nerves. It passes inward across the axillary artery and 
vein, pierces the costo-coracoid membrane, and is distributed to the under surface of 
the Pectoralis major. It sends down a communicating filament to join the internal 
branch, which forms a loop round the inner side of the axillary artery. 
The internal or deep branch arises from the inner cord, and through it from the 
eighth cervical and first dorsal. It passes upward between the axillary artery and 
vein (sometimes perforates the vein), and joins with the filament from the super- 
ficial branch. It then passes to the under surface of the Pectoralis minor muscle, 
where it divides into a number of branches which supply the muscle on its under 
surface. Some of the branches pass through the muscle; others wind round its 
upper border and pierce the costo-coracoid membrane to supply the Pectoralis major. 
The Subscapular Nerves, three in number, supply the Subscapularis, Teres 
major, and Latissimus dorsi muscles. The fasciculi' of which they are composed 
may be traced to the fifth, sixth, and seventh cervical nerve. 
The upper subscapular nerve, the smallest, enters the upper part of the Subscap- 
ularis muscle. 
The lower subscapular nerve enters the axillary border of the Subscapularis and 
terminates in the Teres major. The latter muscle is sometimes supplied by a sepa- 
rate branch. 756 
THE SPINAL NERVES. 
The middle or long subscapular, the largest of the three, follows the course of 
the subscapulai' artery along the posterior wall of the axilla to the Latissimus dorsi, 
through which it may be traced as far as its lower border. 
The Circumflex Nerve (Fig. 506, p. 762) supplies some of the muscles and the 
integument of the shoulder and the shoulder-joint. It arises from the posterior cord 
of the brachial plexus in common with the musculo-spiral nerve, and its fibres may 
be traced through the posterior cord to the fifth, sixth, and seventh cervical nerves. 
It is at first placed behind the axillary artery, between it and the Subscapularis 
muscle, and passes downward and outward to the lower border of that muscle. It 
then winds backward, in company with the posterior circumflex artery, through a 
quadrilateral space bounded above by the Teres minor, below by the Teres major, 
internally by the long head of the Triceps, and externally by the neck of the 
humerus, and divides into two branches. 
The upper branch winds round the neck of the humerus, beneath the Deltoid, 
with the posterior circumflex vessels as far as the anterior border of that muscle, 
supplying it and giving off cutaneous branches which pierce the muscle and ramify 
in the integument covering its lower part. 
The lower branch at its origin distributes filaments to the Teres minor and back 
part of the Deltoid muscles. Upon the filament to the former muscle a gangliform 
enlargement usually exists. The nerve then pierces the deep fascia, and supplies 
the integument over the lower two-thirds of the posterior surface of the Deltoid, as 
well as that covering the long head of the Triceps. 
The circumflex nerve, before its division, gives off an articular filament which 
enters the shoulder-joint below the Subscapularis. 
The Musculo-cutaneous Nerve (Fig. 505, p. 760) {external cutaneous or perfo- 
rans Casserii) supplies some of the muscles of the arm and the integument of the fore- 
arm. It arises from the outer cord of the brachial plexus, receiving filaments from 
the fifth, sixth, and seventh cervical nerves opposite the lower border of the Pec- 
toralis minor. It then perforates the Coraco-brachialis muscle, passes obliquely 
between the Biceps and Brachialis anticus to the outer side of the arm, and a little 
above the elbow winds round the outer border of the tendon of the Biceps, and, 
perforating the deep fascia, becomes cutaneous. This nerve in its course through 
the arm supplies the Coraco-brachialis, Biceps, and part of the Brachialis anticus 
muscles. It sends a small branch to the bone, which enters the nutrient foramen, 
with the accompanying artery and a filament, from the branch supplying the Bra- 
chialis anticus, to the elbow-joint. 
The cutaneous portion of the nerve passes behind the median cephalic vein, and 
divides opposite the elbow-joint into an anterior and a posterior branch. 
The anterior branch descends along the radial border of the forearm to the wrist, 
and supplies the integument over the outer half of the anterior surface. At the wrist- 
joint it is placed in front of the radial artery, and some filaments piercing the deep 
fascia accompany that vessel to the back of the wrist, supplying the carpus. The 
nerve then passes downward to the ball of the thumb, where it terminates in cuta- 
neous filaments. It communicates with a branch from the radial nerve and the 
palmar cutaneous branch of the median. 
The posterior branch passes downward along the back part of the radial side 
of the forearm to the wrist. It supplies the integument of the lower third of the 
forearm, communicating with the radial nerve and the external cutaneous branch of 
the musculo-spiral. 
The Internal Cutaneous Nerve (Fig. 505) is one of the smallest branches of 
the brachial plexus. It arises from the inner cord in common with the ulnar and 
internal head of the median, and at its commencement is placed on the inner side 
of the brachial artery. It derives its fibres from the eighth cervical and first dorsal 
nerves. It passes down the inner side of the arm, pierces the deep fascia with the 
basilic vein about the middle of the limb, and, becoming cutaneous, divides into 
branches. 
This nerve gives off near the axilla a cutaneous filament which pierces the fascia BRANCHES BELOW THE CLAVICLE. 
757 
and supplies the integument covering the Biceps muscle, nearly as far as the elbow. 
This filament lies a little external to the common trunk, from which it arises. 
The anterior branch, the larger of the two, passes usually in front of, but occa- 
sionally behind, the median basilic vein. It then descends on the anterior surface 
[Fig. 501. 
[Fig. 502. 
Posterior. 
Anterior. 
Sa, Supraclavicular nerve. 
IID, Second dorsal. 
PS, Posterior branches of the spinal nerves. 
LI, Lateral branches of the intercostal nerves. 
Al, Anterior branches of the intercostal nerves. 
II, Iliac branch of ilio-inguinal nerve. 
I'H'. Ilio-hypogastric nerve. 
C, Circumflex nerve. 
IH, Intercostal humeral. 
W, Nerve of Wrisberg. 
Cutaneous Nerves of the Trunk, right upper extremity. 
I'CB, Internal cutaneous branch of musculo- 
spiral nerve. 
ECB, external cutaneous branch of musculo- 
spiral nerve. 
ICB, Internal cutaneous nerve. 
MC, Musculo-cutaneous nerve. 
R, Radial nerve. 
U, Ulnar nerve. 
M, Median nerve (after Flower).] 
of the ulnar side of the forearm, distributing filaments to the integument as far as 
the wrist, and communicating with a cutaneous branch of the ulnar nerve. 
The posterior branch passes obliquely downward on the inner side of the basilic 
vein, passes behind the internal condyle of the humerus to the back of the forearm, 
and descends on the posterior surface of its ulnar side as far as the wrist, distrib- 
uting filaments to the integument. It communicates above the elbow with the lesser 
internal cutaneous, and above the wrist with the dorsal cutaneous branch of the ulnar 
nerve (Swan). 
The Lesser Internal Cutaneous Nerve (nerve of Wrisberg) (Fig. 505) is dis- 
tributed to the integument on the inner side of the arm. It is the smallest of the 
branches of the brachial plexus, and, arising from the inner cord with the internal 
cutaneous and ulnar nerves, receives its fibres from the eighth cervical and first dor- 
sal nerves. It passes through the axillary space, at first lying behind, and then on 
the inner side of the axillary vein, and communicates with the intercosto-humeral 
nerve. It descends along the inner side of the brachial artery to the middle of the 
arm, where it pierces the deep fascia, and is distributed to the integument of the 
back part of the lower third of the arm, extending as far as the elbow, where some 758 
THE SPINAL NERVES. 
filaments are lost in the integument in front of the inner condyle, and others over 
the olecranon. It communicates with the posterior branch of the internal cutane- 
ous nerve. 
In some cases the nerve of Wrisberg and intercosto-humeral are connected by 
two or three filaments which form a plexus at the back part of the axilla. In 
Fig. 503. 
Fig. 504. 
Cutaneous Nerves of Right Upper Extremity, 
anterior view. 
Cutaneous Nerves of Right Upper Extremity, 
posterior view. 
other cases the intercosto-humeral is of large size, and takes the place of the nerve 
of Wrisberg, receiving merely a filament of communication from the brachial plexus 
which represents the latter nerve. In other cases this filament is wanting, the place 
of the nerve of Wrisberg being supplied entirely from the intercosto-humeral. BRANCHES BELOW THE CLAVICLE. 
759 
The Median Nerve (Fig. 505) has received its name from the course it takes 
along the middle of the arm and forearm to the hand, lying between the ulnar and 
the musculo-spiral and radial nerves. It arises by two roots-one from the outer 
and one from the inner cord of the brachial plexus; these embrace the lower part 
of the axillary artery, uniting either in front or on the outer side of that vessel. 
It receives filaments from all five cords of the brachial plexus. As it descends 
through the arm it lies at first on the outer side of the brachial artery, crosses that 
vessel in the middle of its course, usually in front, but occasionally behind it, and 
lies on its inner side to the bend of the elbow, where it is placed beneath the bicip- 
ital fascia, and is separated from the elbow-joint by the Brachialis anticus. In the 
forearm it passes between the two heads of the Pronator radii teres, and descends 
beneath the Flexor sublimis, lying on the Flexor profundus, to within two inches 
above the annular ligament, where it becomes more superficial, lying between the 
tendons of the Flexor sublimis and Flexor carpi radialis, beneath, or rather to the 
ulnar side of, the tendon of the Palmaris longus, covered by the integument and 
fascia. It then passes beneath the annular ligament into the hand. In its course 
through the forearm it is accompanied by a small artery. [The median nerve is 
accessible for operation at almost any part of its course.] 
Branches.-No branches are given off from the median nerve in the arm. In 
the forearm its branches are muscular, anterior interosseous, and palmar cutaneous. 
The muscular branches supply all the superficial muscles on the front of the 
forearm, except the Flexor carpi ulnaris. These branches are derived from the 
nerve near the elbow. The branch furnished to the Pronator radii teres often 
arises above the joint. 
The anterior interosseous supplies the deep muscles on the front of the forearm, 
except the inner half of the Flexor profundus digitorum. It accompanies the ante-' 
rior interosseous artery along the interosseous membrane, in the interval between 
the Flexor longus pollicis and Flexor profundus digitorum muscles, both of which 
it supplies, and terminates below in the Pronator quadratus. 
The palmar cutaneous branch arises from the median nerve at the lower part of 
the forearm. It pierces the fascia above the annular ligament, and, descending over 
that ligament, divides into two branches, of which the outer supplies the skin over 
the ball of the thumb, and communicates with the anterior branch of the external 
cutaneous nerve, and the inner supplies the integument of the palm of the hand, 
communicating with the cutaneous branch of the ulnar. 
In the palm of the hand the median nerve is covered by the integument and 
palmar fascia, and rests upon the tendons of the Flexor muscles. In this situ- 
ation it becomes enlarged, somewhat flattened, of a reddish color, and divides into 
two branches. Of these, the external supplies a muscular branch to some of the 
muscles of the thumb and digital branches to the thumb and index finger, the 
internal supplying digital branches to the contiguous sides of the index and middle 
and of the middle and ring fingers. 
The branch to the muscles of the thumb is a short nerve which subdivides to 
supply the Abductor, Opponens, and outer head of the Flexor brevis pollicis mus- 
cles, the remaining muscles of this group being supplied by the ulnar nerve. 
The digital branches are five in number. The first and second pass along the 
borders of the thumb, the external branch communicating with branches of the 
radial nerve. The third passes along the radial side of the index finger, and sup- 
plies the first Lumbricalis muscle. The fourth subdivides to supply the adjacent 
sides of the index and middle fingers, and sends a branch to the second Lumbri- 
calis muscle. The fifth supplies the adjacent sides of the middle and ring fingers, 
and communicates with a branch from the ulnar nerve. 
Each digital nerve opposite the base of the first phalanx gives off a dorsal 
branch, which joins the dorsal digital nerve from the radial and runs along the side 
of the dorsum of the finger, to end in the integument over the last phalanx. At 
the end of the finger the digital nerve divides into a palmar and a dorsal branch, 
the former of which supplies the extremity of the finger, and the lattei' ramifies 760 
THE SPINAL NEEVES. 
Fig. 505. 
External 
"Anterior T7io reteio 
Infernal 
"Anterior Thoracic 
Ala sc alo- 
Cutaneous 
- Median 
N / i 
Ulnctr / 
Internal 
Cutaneous 
Musculo Spiral 
Posterior 
Interosseous 
■ Ba (Icat 
Vlnur 
.Anterior 
In te rosseou 3 
jDorsal ' 
Brand 
JDeep~ 
.Branch 
Nerves of the Left Upper Extremity. BRANCHES BELOW THE CLAVICLE. 
761 
round and beneath the nail. The digital nerves, as they run along the fingers, are 
placed superficial to the digital arteries. [The careful observations of Weir Mitch- 
ell,1 and others, after section of the nerves supplying the skin of the 
hand, have shown that the region supplied by the same nerve in different persons 
varies very much, and also that there must be peripheral anastomoses which can 
scarcely be dissected, but are well determined by such physiological experiments.] 
The Ulnar Nerve (Fig. 505) is placed along the inner or ulnar side of the upper 
limb, and is distributed to the muscles and integument of the forearm and hand. 
It is smaller than the median, behind which it is placed, diverging from it in its 
course down the arm. It arises from the inner cord of the brachial plexus, in 
common with the inner head of the median and the internal cutaneous nerve, and 
derives its fibres from the eighth cervical and first dorsal nerves. At its com- 
mencement it lies at the inner side of the axillary artery, and holds the same rela- 
tion with the brachial artery to the middle of the arm. From this point it runs 
obliquely across the internal head of the Triceps, pierces the internal intermuscular 
septum, and descends to the groove between the internal condyle and the olecranon, 
accompanied by the inferior profunda artery. [In resection of the elbow great care 
must be taken not to wound the nerve in this situation.] At the elbow it rests upon 
the back of the inner condyle, and passes into the forearm between the two heads 
of the Flexor carpi ulnaris. In the forearm it descends in a perfectly straight 
course along its ulnar side, lying upon the Flexor profundus digitorum, its upper 
half being covered by the Flexor carpi ulnaris, its lower half lying on the outer 
side of the muscle, covered by the integument and fascia. The ulnar artery, in the 
upper third of its course, is separated from the ulnar nerve by a considerable inter- 
val, but in the rest of its extent the nerve lies to its inner side. At the wrist the 
ulnar nerve crosses the annular ligament on the outer side of the pisiform bone a 
little behind the ulnar artery, and immediately beyond this bone divides into two 
branches, superficial and deep palmar. [The ulnar nerve is accessible for operation 
in nearly its whole length, except just above and below the elbow.] 
The branches of the ulnar nerve are- 
' Articular (elbow). 
Muscular. 
Cutaneous. 
Dorsal cutaneous. 
Articular (wrist). 
In the forearm 
In the hand 
Superficial palmar. 
Deep palmar. 
The articular branches distributed to the elbow-joint consist of several small 
filaments. They arise from the nerve as it lies in the groove between the inner 
condyle and olecranon. 
The muscular branches are two in number-one supplying the Flexor carpi 
ulnaris, the other the inner half of the Flexor profundus digitorum. They arise 
from the trunk of the nerve near the elbow. 
The cutaneous branch arises from the ulnar nerve about the middle of the fore- 
arm, and divides into two branches. 
The one branch (frequently absent) pierces the deep fascia near the wrist, and 
is distributed to the integument, communicating with a branch of the internal cuta- 
neous nerve. 
The second branch (palmar cutaneous) lies on the ulnar artery, which it 
accompanies to the hand, some filaments entwining round the vessel; it ends 
in the integument of the palm, communicating with branches of the median 
nerve. 
The dorsal cutaneous branch arises about two inches above the wrist; it passes 
backward beneath the Flexor carpi ulnaris, perforates the deep fascia, and, running 
along the ulnar side of the back of the wrist and hand, supplies the inner side of 
the little finger and the adjoining sides of the little and ring fingers; it communi- 
O1 See especially the Trans. Coll. Phys. Phila., 1876, and Brain, Oct., 1878.] 762 
THE SPINAL NERVES. 
cates with the posterior branch of the internal cutaneous nerve, and sends a com- 
municating filament to that branch of the radial nerve which supplies the adjoining 
sides of the middle and ring fingers. 
The articular filaments to the wrist are also supplied by the ulnar nerve. 
The superficial palmar branch supplies the Palmaris brevis and the integument 
on the inner side of the hand, and terminates in two digital branches, which are 
distributed, one to the ulnar 
side of the little finger, the 
other to the adjoining sides 
of the little and ring fingers, 
the latter communicating with 
a branch from the median. 
The digital branches are dis- 
tributed to the fingers in the 
same manner as the digital 
branches of the median al- 
ready described. 
The deep palmar branch 
passes between the Abductor 
and Flexor brevis minimi 
digiti muscles, and follows 
the course of the deep palmar 
arch beneath the flexor ten- 
dons. At its origin it sup- 
plies the muscles of the little 
finger. As it crosses the deep 
part of the hand it sends two 
branches to each interosseous 
space, one for the Dorsal and 
one for the Palmar interosse- 
ous muscle, the branches to the 
second and third Palmar in- 
terossei supplying filaments 
to the two inner Lumbricales 
muscles. At its termination 
between the thumb and index 
finger it supplies the Adductor' 
pollicis and the inner head of 
the Flexor brevis pollicis. 
The Musculo-spiral 
Nerve (Fig. 506), the largest 
branch of the brachial plexus, 
supplies the muscles of the 
back part of the arm and 
forearm and the integument 
of the same parts, as well as 
that of the back of the hand. 
It arises from the posterior cord 
of the brachial plexus by a com- 
mon trunk with the circum- 
flex nerve, and is afterward 
joined by the posterior divis- 
ion of the trunk, formed by 
the junction of the eighth cer- 
vical and first dorsal nerves. It receives filaments from all the five spinal nerves 
forming the brachial plexus. At its commencement it is placed behind the axillary 
and upper part of the brachial arteries, passing down in front of the tendons of the 
Fig. 506. 
Supra Scapula. 
■ Circumflex 
-Mustu lo-Sjiiya 1 
-Posterior-Intorosieoui 
The Suprascapular, Circumflex, and Musculo-spiral Nerves. BRANCHES BELOW THE CLAVICLE. 
763 
Latissimus dorsi and Teres major. It winds round the humerus in the musculo- 
spiral groove with the superior profunda artery, passing from the inner side of the 
bone, between the internal and external heads of the Triceps muscle. It pierces 
the external intermuscular septum, and descends between the Brachialis anticus and 
Supinator longus to the front of the external condyle, where it divides into the 
radial and posterior interosseous nerves. [In its course between the Brachialis 
anticus and the Supinator longus it is accessible for operation.] 
The branches of the musculo-spiral nerve are- 
Muscular. 
Radial. 
Cutaneous. 
Posterior interosseous. 
The muscular branches are divided into internal, posterior, and external: they 
supply the Triceps, Anconeus, Supinator longus, Extensor carpi radialis longior, and 
Brachialis anticus. These branches are derived from the nerve at the inner side, 
back part, and outer side of the arm. 
The internal muscular branches supply the inner and middle heads of the Tri- 
ceps muscle. That to the inner head of the Triceps is a long, slender filament 
which lies close to the ulnar nerve, as far as the lower third of the arm, and is often 
intimately connected with it. 
The posterior muscular branch, of large size, arises from the nerve in the groove 
between the Triceps and the humerus. It divides into branches which supply the 
outer head of the Triceps and Anconeus muscles. The branch for the latter mus- 
cle is a long, slender filament which descends in the substance of the Triceps to the 
Anconeus. 
The external muscular branches supply the Supinator longus, Extensor carpi 
radialis longior, and usually the outer part of the Brachialis anticus. 
The cutaneous branches are three in number, one internal and two external. 
The internal cutaneous branch arises in the axillary space with the inner mus- 
cular branch. It is of small size, and passes through the axilla to the inner side 
of the arm, supplying the integument on its posterior aspect nearly as far as the 
olecranon. In its course it crosses beneath the intercosto-humeral, with which it 
communicates. 
The two external cutaneous branches perforate the outer head of the Triceps at 
its attachment to the humerus. The upper and smaller one follows the course of 
the cephalic vein to the front of the elbow, supplying the integument of the lower 
half of the upper arm on its anterior aspect. The lower branch pierces the deep 
fascia below the insertion of the Deltoid, and passes down along the outer side of 
the arm and elbow, and along the back part of the radial side of the forearm to 
the wrist, supplying the integument in its course, and joining, near its termination, 
with the posterior branch of the external cutaneous nerve. 
The Radial Nerve passes along the front of the radial side of the forearm to 
the commencement of its lower third. It lies at first a little to the outer side of 
the radial artery, concealed beneath the Supinator longus. In the middle third of 
the forearm it lies beneath the same muscle, in close relation with the outer side of 
the artery. It quits the artery about three inches above the wrist, passes beneath 
the tendon of the Supinator longus, and, piercing the deep fascia at the outer bor- 
der of the forearm, divides into two branches. 
The external branch, the smaller of the two, supplies the integument of the 
radial side and ball of the thumb, joining with the anterior branch of the external 
cutaneous nerve. 
The internal branch communicates above the wrist with the posterior branch 
from the external cutaneous, and on the back of the hand forms an arch with the 
dorsal cutaneous branch of the ulnar nerve. It then divides into three digital 
nerves, which are distributed as follows: the first supplies the ulnar side of the 
thumb and the radial side of the index finger; the second, the adjoining sides of 
the index and middle fingers; and the third, the adjacent borders of the middle 764 
THE SPINAL NERVES. 
and ring fingers.1 The latter nerve communicates with a filament from the dorsal 
branch of the ulnar nerve. 
The Posterior Interosseous Nerve winds to the back of the forearm through 
the fibres of the Supinator brevis, and passes down between the superficial and deep 
layers of muscles to the middle of the forearm. Considerably diminished in size, it 
descends on the interosseous membrane, beneath the Extensor secundi internodii 
pollicis, to the back of the carpus, where it presents a gangliform enlargement from 
which filaments are distributed to the ligaments and articulations of the carpus. 
It supplies all the muscles of the radial and posterior brachial regions, excepting 
the Anconeus, Supinator longus, and Extensor carpi radialis longior. 
DORSAL NERVES (Fig. 507). 
The Dorsal Nerves are twelve in number on each side. The first appears 
between the first and second dorsal vertebrae, and the last between the last dorsal 
and first lumbar. 
The roots of origin of the dorsal nerves are of small size and vary but slightly 
from the second to the last. Both roots are very slender, the posterior roots only 
slightly exceeding the anterior in thickness. They gradually increase in length 
from above downward, and pass down in contact with the spinal cord, for a distance 
equal to a height of at least two vertebrae in the lower part of the dorsal region, 
before they emerge from the spinal canal. They then join in the intervertebral 
foramen, and at their exit divide into two primary divisions-a posterior (dorsal) 
and an anterior (intercostal). 
The first and last dorsal nerves are peculiar in some respects. (See pp. 766, 767.) 
Posterior Divisions of the Dorsal Nerves. 
The posterior divisions of the dorsal nerves, which are smaller than the 
anterior, pass backward between the transverse processes, and divide into external 
and internal branches. 
The external branches increase in size from above downward. They pass 
through the Longissimus dorsi to the cellular interval between it and the Sacro- 
lumbalis, and supply those muscles, as well as their continuations upward to the 
head and the Levatores costarum; the five or six lower nerves also give off cutane- 
ous filaments. 
The internal branches of the six upper nerves pass inward to the interval 
between the Multifidus spinee and Semispinalis dorsi muscles, which they supply, 
and then, piercing the origin of the Rhomboidei and Trapezius, become cutaneous 
by the side of the spinous processes. The internal branches of the six lower 
nerves are distributed to the Multifidus spinae without giving off any cutaneous 
filaments. 
The cutaneous branches of the dorsal nerves are twelve in number, the six 
upper being derived from the internal branches, and the six lower from the 
external branches. The former pierce the Rhomboid and Trapezius muscles close 
to the spinous processes and ramify in the integument. They are frequently fur- 
nished with gangliform enlargements. The six lower cutaneous branches pierce the 
Serratus posticus inferior and Latissimus dorsi in a line with the angles of the ribs. 
Anterior Divisions of the Dorsal Nerves. 
The anterior divisions of the dorsal nerves (intercostal nerves) are twelve in 
number on each side. They are, for the most part, distributed to the parietes of the 
1 According to Hutchinson, the digital nerve to the thumb reaches only as high as the root of the 
nail; on the forefinger, as high as the middle of the second phalanx ; on the middle and ring fingers, 
not higher than the first phalangeal joint (London Hosp. Gaz., vol. iii. p. 319). ANTERIOR DIVISIONS OF THE DORSAL NERVES. 
765 
Fig. 507. 
Superficial and Deep Distribution of the Posterior Branches of the Spinal Nerves (after Hirschfeld and LeveillS). 
On the left side the cutaneous branches are represented lying on the superficial layer of muscles. On the 
right side the superficial muscles have been removed, the Splenius capitis and Complexus divided in the 
neck, and the Erector spinee divided and partly removed in the back, so as to expose the posterior divisions 
of the spinal nerves near their origin: a, a, lesser occipital nerve from the cervical plexus; 1, external mus- 
cular branches of the first cervical nerve, and union by a loop with the second; 2, placed on the Rectus cap- 
itis posticus major muscle, marks the great occipital nerve, passing round the short muscles and piercing 
the Complexus: the external branch is seen to the outside; 3, external branch from the posterior division 
of the third nerve; 3', its internal branch, sometimes called the third occipital: 4'to 8', the internal branches 
of the several corresponding nerves on the left side : the external branches of these nerves, proceeding to 
muscles are displayed on the right side; dl to <26, and thence to d!2, external muscular branches of the 
posterior divisions of the twelve dorsal nerves on the right side; dl'to d 6', the internal cutaneous branches of 
the six upper dorsal nerves on the left side; ' d 7' to d 12', cutaneous twigs from the external branches of the 
six lower dorsal nerves; I, I, external branches from the posterior divisions of several lumbar nerves on the 
right side piercing the muscles, the lower descending over the gluteal region ; I', I'; the same, more super- 
ficially on the left side; s, s, the issue and union by loops of the posterior divisions of four sacral nerves on 
the right side ' s' s', scjne of those distributed to the skin on the left side. 766 
THE SPINAL NERVES. 
thorax and abdomen, separately from each other, without being joined in a plexus; 
in which respect they differ from the other spinal nerves. Each nerve is connected 
with the adjoining ganglia of the sympathetic by one or two filaments. The inter- 
costal nerves may be divided into two sets, from the difference they present in their 
distribution. The six upper, with the exception of the first and the intercosto- 
humeral branch of the second, are limited in their distribution to the parietes of the 
chest. The six lower supply the parietes of the chest and abdomen, the last one 
sending a cutaneous filament to the hip. 
The First Dorsal Nerve.-The anterior division of the first dorsal nerve 
divides into two branches: one, the larger, leaves the thorax in front of the neck 
of the first rib and enters into the formation of the brachial plexus; the other and 
smaller branch runs along the first intercostal space, forming the first intercostal 
nerve, and terminates on the front of the chest by forming the first anterior cutane- 
ous nerve of the thorax. The first intercostal nerve gives off no lateral cutaneous 
branch. 
The Upper Six Dorsal Nerves.-The anterior divisions of the second, third, 
fourth, fifth, and sixth dorsal nerves and the small branch from the first dorsal are 
confined to the parietes of the thorax, and are named upper or pectoral intercostal 
nerves. They pass forward in the intercostal spaces with the intercostal vessels, 
being situated below them. At the back of the chest they lie between the pleura 
and the External intercostal muscle, but are soon placed between the two planes of 
intercostal muscles as far as the middle of the rib. They then enter the substance 
of the Internal intercostal muscles, and running amidst their fibres as far as the cos- 
tal cartilages, they gain the inner surface of the muscles and lie between them and 
the pleura. Near the sternum they cross the internal mammary artery and Trian- 
gularis sterni, pierce the Internal intercostal and Pectoralis major muscles, and supply 
the integument of the mamma and front of the chest, forming the anterior cutane- 
ous nerves of the thorax, the branch from the second nerve becoming joined with 
the supraclavicular nerves of the cervical plexus. 
Branches.-Numerous slender muscular filaments supply the Intercostal and 
Triangularis sterni muscles. Some of these branches at the front of the chest cross 
the costal cartilages from one to another intercostal space. 
Lateral Cutaneous Nerves.-These are derived from the intercostal nerves, mid- 
way between the vertebrae and sternum; they pierce the External intercostal and 
Serratus magnus muscles and divide into tw'o branches, anterior and posterior. 
The anterior branches are reflected forward to the side and the fore part of the 
chest, supplying the integument of the chest and mamma and the upper digitations 
of the External oblique. 
The posterior branches are reflected backward to supply the integument over the 
scapula and over the Latissimus dorsi. 
The first intercostal nerve has no lateral cutaneous branch. The lateral cutane- 
ous branch of the second intercostal nerve is of large size, and does not divide like 
the other nerves into an anterior and posterior branch. It is named, from its origin 
and distribution, the intercosto-humeral nerve (Fig. 505, p. 760). It pierces the Ex- 
ternal intercostal muscle, crosses the axilla to the inner side of the arm, and joins 
with a filament from the nerve of Wrisberg. It then pierces the fascia, and supplies 
the skin of the upper half of the inner and back part of the arm, communicating with 
the internal cutaneous branch of the musculo-spiral nerve. The size of this nerve 
is in inverse proportion to the size of the other cutaneous nerves, especially the 
nerve of Wrisberg. A second intercosto-humeral nerve is frequently given off from 
the third intercostal. It supplies filaments to the armpit and inner side of the arm. 
The Lower Six Dorsal Nerves.-The anterior divisions of the seventh, eighth, 
ninth, tenth, and eleventh dorsal nerves are continued anteriorly from the intercostal 
spaces into the abdominal wall, and the twelfth dorsal is continued throughout its 
whole course in the abdominal wall, since it is placed below the last rib ; hence 
these nerves are named lower or abdominal intercostal nerves. They have (with 
the exception of the last) the same arrangement as the upper ones as far as the LUMBAR NERVES. 
767 
anterior extremities of the intercostal spaces, where they pass behind the costal car- 
tilages and between the Internal oblique and Transversalis muscles to the sheath of 
the Rectus, which they perforate. They supply the Rectus muscle, and terminate 
in branches which become subcutaneous near the linea alba. These branches, which 
are named the anterior cutaneous nerves of the abdomen, supply the integument of 
the front of the belly; they are directed outward as far as the lateral cutaneous 
nerves. The lower intercostal nerves supply the intercostal and abdominal mus- 
cles, and about the middle of their course give off lateral cutaneous branches, which 
pierce the External intercostal and External oblique muscles and are distributed to 
the integument of the abdomen, the anterior branches passing nearly as far forward 
as the margin of the Rectus, the posterior branches passing to supply the skin over 
the Latissimus dorsi, where they join the dorsal cutaneous nerves. 
The last dorsal is larger than the other dorsal nerves. Its anterior division 
runs along the lower border of the last rib in front of the Quadratus lumborum, 
perforates the aponeurosis of the Transversalis, and passes forward between it and 
the Internal oblique, to be distributed in the same manner as the preceding nerves. 
It communicates with the ilio-hypogastric branch of the lumbar plexus, and is fre- 
quently connected with the first lumbar nerve by a slender branch, the dorsi-lum- 
bar nerve, which descends in the substance of the Quadratus lumborum. 
The lateral cutaneous branch of the last dorsal is remarkable for its large size; 
it perforates the Internal and External oblique muscles, passes downward over the 
crest of the ilium in front of the iliac branch of the ilio-hypogastric (Fig. 515, p. 
779), and is distributed to the integument of the front of the hip, some of its fila- 
ments extending as low down as the trochanter major. It does not divide into an 
anterior and posterior branch like the others. 
The lumbar nerves are five in number on each side: the first appears between 
the first and second lumbar vertebrae, and the last between the last lumbar and the 
base of the sacrum. 
The roots of the lumbar nerves are the largest and their filaments the most 
numerous of all the spinal nerves, and they are closely aggregated together upon 
the lower end of the cord. The anterior roots are the smaller, but there is not the 
same disproportion between them and the posterior roots as in the cervical nerves. 
The roots of these nerves have a vertical direction and are of considerable length, 
more especially the lower ones, since the spinal cord does not extend beyond the 
first lumbar vertebra. The roots become joined in the intervertebral foramina, and 
the nerves, so formed, divide at their exit into two divisions, anterior and posterior. 
LUMBAR NERVES. 
The posterior divisions of the lumbar nerves (Fig. 507, p. 765) diminish in 
size from above downward; they pass backward between the transverse processes 
and divide into external and internal branches. 
The external branches supply the Erector spinae and Intertransverse muscles. 
From the three upper branches cutaneous nerves are derived which pierce the apo- 
neurosis of the Latissimus dorsi muscle and descend over the back part of the crest 
of the ilium, to be distributed to the integument of the gluteal region, some of the 
filaments passing as far as the trochanter major. 
The internal branches, the smaller, pass inward close to the articular processes of 
the vertebrae, and supply the Multifidus spinae and Interspinales muscles. 
Posterior Divisions of the Lumbar Nerves. 
Anterior Divisions of the Lumbar Nerves. 
The anterior divisions of the lumbar nerves increase in size from above down- 
ward. At their origin they communicate with the lumbar ganglia of the sympa- 768 
THE SPINAL NERVES. 
thetic by long slender filaments, which accompany the lumbar arteries round the 
sides of the bodies of the vertebrae beneath the Psoas muscle. The nerves pass 
obliquely outward behind the Psoas magnus or between its fasciculi, distributing 
filaments to it and the Quadratus lumborum. The anterior divisions of the four 
upper nerves are connected together in this situation by anastomotic loops, and 
form the lumbar plexus. The anterior division of the fifth lumbar, joined with a 
branch from the fourth, descends across the base of the sacrum to join the ante- 
rior division of the first sacral nerve and assist in the formation of the sacral 
plexus. The cord resulting from the union of the fifth lumbar and the branch 
from the fourth is called the lumbo-sacral nerve. 
Lumbar Plexus. 
The lumbar plexus is formed by the loops of communication between the ante- 
rior divisions of the four upper lumbar nerves. The plexus is narrow above, and 
often connected with the last dorsal by a slender branch, the dorsi-luvibar nerve; it 
is broad below, where it is joined 
to the sacral plexus by the lumbo- 
sacral cord. It is situated in the 
substance of the Psoas muscle near 
its posterior part, in front of the 
transverse processes of the lumbar 
vertebrae. 
The mode in which the plexus 
is formed is the following: The first 
lumbar nerve receives a branch from 
the last dorsal, and gives off the ilio- 
hypogastric and ilio-inguinal, and a 
communicating branch which passes 
down to the second lumbar and 
forms a part of the genito-crural 
nerve. The second gives off the 
remainder of the genito-crural and 
a descending branch to communi- 
cate with the third; from it the 
greater part of the external cuta- 
neous is given off. The fibres 
of this communicating branch are 
prolonged partly into the ante- 
rior crural and partly into the obturator nerve. 
The third lumbar nerve gives off a small filament to the external cutaneous and 
divides into two large branches, which assist in forming the anterior crural and obtu- 
rator nerves. When the accessory obturator exists some of its fibres are derived from 
this third nerve. It also gives off a communicating branch to the fourth. The fourth 
nerve gives a communicating filament to the fifth, and divides into two branches, 
which complete the anterior crural and obturator. Sometimes it also furnishes part 
of the accessory obturator. 
From this arrangement it follows that the ilio-hypogastric and ilio-inguinal are 
derived entirely from the first lumbar nerve; the genito-crural partly from the first, 
but principally from the second nerve; the external cutaneous for the most part from 
the second, but receiving a small filament from the third; the anterior crural and 
obturator by fibres derived from the second, third, and fourth; and the accessory 
obturator, when it exists, from the third and fourth, probably receiving also some 
fibres from the second through its communicating branch. 
The branches of the lumbar plexus are the 
C. WITH 121!? DORSAk 
Fig. 508. 
I 
n 
in 
ILIO-HYPOGASTRIC 
ILIO -INGUINAL 
GENITO -CRURAL 
EXT. CUTANEOUS 
ANT. CRURAL 
} OBTURATOR 
G< WITH SIS* 
'ACCESSORY 
,OBTURATOR 
Plan of the Lumbar Plexus. LUMBAR PLEXUS. 
769 
Ilio-hypogastric. 
Ilio-inguinal. 
Genito-crural. 
External cutaneous. 
Obturator. 
Accessory obturator. 
Anterior crural. 
The Ilio-hypogastric Nerve (superior musculo-cutaneous) arises from the first 
lumbar nerve. It emerges from the outer border of the Psoas muscle at its upper 
part, and crosses obliquely in front of the Quadratus lumborum to the crest of the 
Fig. 509. 
The Lumbar Plexus and its Branches.1 
ilium. It then perforates the Transversalis muscle at its back part, and divides 
between it and the Internal oblique into two branches, iliac and hypogastric. 
The z'Zzac branch pierces the Internal and External oblique muscles immediately 
above the crest of the ilium, and is distributed to the integument of the gluteal 
region, behind the lateral cutaneous branch of the last dorsal nerve (Fig. 515, p. 
779). The size of this nerve bears an inverse proportion to that of the cutaneous 
branch of the last dorsal nerve. 
The hypogastric branch (Fig. 510) continues onward between the Internal 
oblique and Transversalis muscles. It then pierces the Internal oblique, and 
near the middle line perforates the aponeurosis of the External oblique above 
the external abdominal ring, and is distributed to the integument. covering the 
hypogastric region. 
1 The arrangement of the lumbar plexus on the right side in this woodcut is not strictly correct. 
(See the plan on preceding page.) 
49 770 
THE SPINAL NERVES. 
The ilio-hypogastric nerve communicates with the last dorsal and ilio-inguina] 
nerves. 
The Ilio-inguinal Nerve {inferior musculo-cutaneous), smaller than the pre- 
ceding, arises with it from the first lumbar nerve. It emerges from the outer bor- 
der of the Psoas just below the ilio-hypogastric, and, passing obliquely across the 
Quadratus lumborum and Iliacus muscles, perforates the Transversalis near the fore 
part of the crest of the ilium, and communicates with the ilio-hypogastric nerve 
between that muscle and the Internal oblique. The nerve then pierces the Internal 
oblique, distributing filaments to it, and, accompanying the spermatic cord through 
the inguinal canal, it escapes at the external abdominal ring, and is distributed to 
the integument of the upper and inner part of the thigh, and to the scrotum in the 
male and to the labium in the female. The size of this nerve is in inverse propor- 
tion to that of the ilio-hypogastric. Occasionally it is very small, and ends by 
joining the ilio-hypogastric; in such cases a branch from the ilio-hypogastric takes 
the place of the ilio-inguinal, or the latter nerve may be altogether absent. 
The G-enito-crural Nerve arises from the second lumbar, and by a few fibres 
from the cord of communication between it and the first. It passes obliquely 
through the substance of the Psoas, descends on its surface to near Poupart's liga- 
ment, and divides into a genital and crural branch. 
The genital branch descends on the external iliac artery, sending a few filaments 
round that vessel; it then pierces the fascia transversalis or passes through the 
internal abdominal ring, descends along the back part of the spermatic cord to the 
scrotum, and supplies, in the male, the Cremaster muscle; in the female it accom- 
panies the round ligament, and is lost upon it. 
The crural branch passes along the inner margin of the Psoas muscle, beneath 
Poupart's ligament, into the thigh, entering the sheath of the femoral vessels and 
lying superficial and a little external to the femoral artery. It pierces the anterior 
layer of the sheath of the vessels, and, becoming superficial by passing through the 
fascia lata, it supplies the skin of the anterior aspect of the thigh as far as midway 
between the pelvis and knee. On the front of the thigh it communicates with the 
outer branch of the middle cutaneous nerve, derived from the anterior crural. 
A few filaments from this nerve may be traced on to the femoral artery; they 
are derived from the nerve as it passes beneath Poupart's ligament. 
The External Cutaneous Nerve arises from the second and third lumbar 
nerves. It emerges from the outer border of the Psoas muscle about its middle, 
and crosses the Iliacus muscle obliquely to the notch immediately beneath the ante- 
rior superior spine of the ilium, where it passes under Poupart's ligament into the 
thigh and divides into two branches of nearly equal size. 
The anterior branch descends in an aponeurotic canal formed in the fascia lata, 
becomes superficial about four inches below Poupart's ligament, and divides into 
branches which are distributed to the integument along the anterior and outer part 
of the thigh as far down as the knee. This nerve occasionally communicates with 
the long saphenous nerve in front of the knee-joint. 
The posterior branch pierces the fascia lata, and subdivides into branches which 
pass backward across the outer and posterior surface of the thigh, supplying the 
integument from the crest of the ilium as far as the middle of the thigh. 
The Obturator Nerve supplies the Obturator externus and Adductor muscles 
of the thigh, the articulations of the hip and knee, and occasionally the integument 
of the thigh and leg. It arises by two branches: one from the third, the other 
from the fourth lumbar nerve, receiving also some fibres from the second. It 
descends through the inner fibres of the Psoas muscle, and emerges from its inner 
border near the brim of the pelvis; it then runs along the lateral wall of the pelvis, 
above the obturator vessels, to the upper part of the obturator foramen, where it 
enters the thigh, and divides into an anterior and a posterior branch separated by 
the Adductor brevis muscle. 
The anterior branch (Fig. -511) passes down in front of the Adductor brevis, 
being covered by the Pectineus and Adductor longus, and at the lower border of LUMBAR PLEXUS. 
771 
Fig. 510. 
Fig. 511. 
External 
Cutaneous 
Anterior 
Crural 
NUJlr 
Clit a neo us 
Ante rear Divition 
- of OhtiLvatoT 
~ Internal 
Cutaneous 
Internal 
Sajjhe.nou& 
AIllSOUlo- _ 
Cuta/ncous 
Anterior 
Tilinl 
Hxt. tfafiihanoas. 
.Ant. Tibia> 
Cutaneous Nerves of Lower Extremity, front 
view. 
Nerves of the Lower Extremity, front view. 772 
THE SPINAL NERVES. 
the latter muscle communicates with the internal cutaneous and internal saphenous 
nerves, forming a kind of plexus. It then descends upon the femoral artery, upon 
which it is finally distributed. 
This nerve near the obturator foramen gives off an articular branch to the hip- 
joint. Behind the Pectineus it distributes muscular branches to the Adductor 
longus and Gracilis, and occasionally to the Adductor brevis and Pectineus, and 
receives a communicating branch from the accessory obturator nerve. 
[Fig. 512. 
Lumbar Plexus: 
IH, Ilio-hypogastric nerve. 
II, Ilio-inguinal. 
IIL, Second lumbar nerve. 
GC, Genlto-crural. 
EC, External cutaneous. 
MC, Middle cutaneous. 
IC, internal cutaneous. 
IS, Internal saphenous. 
PP, Plexus patellse. 
I'H', Inferior hemorrhoidal of pudic. 
Cutaneous Nerves of the Lower Extremity. 
Sacral Plexus: 
DP, Dorsalis penis of pudic. 
IP, Inferior hemorrhoidal of pudic. 
P, Superficial perineal of pudic and inferior 
pudendal of small sciatic. 
IG, Inferior gluteal of small sciatic. 
SS. Small sciatic. 
EP, Branches from external popliteal. 
ES, External saphenous. 
MCS, Musculo-cutaneous. 
AT, Branches of anterior tibial. 
PT, Branch of posterior tibial (after Flower).] 
Occasionally this communicating branch is continued down, as a cutaneous 
branch, to the thigh and leg. This occasional cutaneous branch emerges from 
beneath the lower border of the Adductor longus, descends along the posterior 
margin of the Sartorius to the inner side of the knee, where it pierces the deep 
fascia, communicates with the long saphenous nerve, and is distributed to the integ- 
ument of the inner side of the leg as low down as its middle. When the branch is 
small its place is supplied by the internal cutaneous nerve. 
The posterior branch of the obturator nerve pierces the Obturator externus, 
sending branches to supply it, and passes behind the Adductor brevis on the front 
of the Adductor magnus, where it divides into numerous muscular branches, which LUMBAR PLEXUS. 
773 
supply the Adductor magnus and occasionally the Adductor brevis. One of the 
branches gives off' a filament to the knee-joint. 
The articular branch for the knee-joint perforates the lower part of the Adduc- 
tor magnus and enters the popliteal space; it then descends upon the popliteal 
artery as far as the back part of the knee-joint, where it perforates the posterior 
ligament and is distributed to the synovial membrane. It gives filaments to the 
artery in its course. 
The Accessory Obturator Nerve (Fig. 509, p. 769) is of a small size, and 
arises either from the obturator nerve near its origin or by separate filaments from 
the third and fourth lumbar nerves, probably receiving also some fibres from the 
second through its communicating branch. It descends along the inner border of 
the Psoas muscle, crosses the body of the pubes, and passes beneath the Pectineus 
muscle, where it divides into numerous branches. One of these supplies the Pec- 
tineus, penetrating its under surface, another is distributed to the hip-joint, while a 
third communicates with the anterior branch of the obturator nerve. This branch, 
when of large size, is prolonged (as already mentioned) as a cutaneous branch to 
the leg. The accessory obturator nerve is not constantly found; when absent, the 
hip-joint receives two branches from the obturator nerve. Occasionally it is very 
small and becomes lost in the capsule of the hip-joint. 
The Anterior Crural Nerve (Figs. 509, 511) is the largest branch of the lum- 
bar plexus. It supplies muscular branches to the Iliacus, Pectineus, and all the 
muscles on the front of the thigh, excepting the Tensor vaginae femoris, cutaneous 
filaments to the front and inner side of the thigh and to the leg and foot, and artic- 
ular branches to the knee. It arises from the third and fourth lumbar nerves, 
receiving also a fasciculus from the second. It descends through the fibres of the 
Psoas muscle, emerging from it at the lower part of its outer border, and passes 
down between it and the Iliacus, and beneath Poupart's ligament, into the thigh, 
where it becomes somewhat flattened and divides into an anterior or cutaneous and 
a posterior or muscular part. Beneath Poupart's ligament it is separated from the 
femoral artery by the Psoas muscle, and lies beneath the iliac fascia. 
Within the pelvis the anterior crural nerve gives off from its outer side some 
small branches to the Iliacus, and a branch to the femoral artery, which is distrib- 
uted upon the upper part of that vessel. The origin of this branch varies; it occa- 
sionally arises higher than usual, or it may arise lower down in the thigh. 
External to the pelvis the following branches are given off: 
From the Anterior Division.1 
Middle cutaneous. 
Internal cutaneous. 
Long saphenous. 
From the Posterior Division. 
Muscular. 
Articular. 
The middle cutaneous nerve (Fig. 510) pierces the fascia lata (occasionally the 
Sartorius also) about three inches below Poupart's ligament, and divides into two 
branches, which descend in immediate proximity along the fore part of the thigh, 
distributing numerous branches to the integument as low as the front of the knee, 
where it communicates with a branch of the internal saphenous nerve. Its outer 
branch communicates above with the crural branch of the genito-crural nerve, and 
the inner branch with the internal cutaneous nerve below. The Sartorius muscle 
is supplied by this or the following nerve. 
The internal cutaneous nerve passes obliquely across the upper ppvt of the sheath 
of the femoral artery, and divides in front or at the inner side of that vessel into 
two branches, anterior and internal. 
The anterior branch perforates the fascia lata at the lower third of the thigh, 
and divides into two branches, one of which supplies the integument as low down 
as the inner side of the knee; the other crosses the patella to the outer side of the 
joint, communicating in its course with the long saphenous nerve. A cutaneous 
1 One of the muscles of the thigh, the Sartorius, receives its nervous supply from this group. 774 
THE SPINAL NERVES. 
filament is occasionally given off from this nerve which accompanies the long saphe- 
nous vein, and it sometimes communicates with the internal branch of the nerve. 
The internal branch descends along the inner border of the Sartorius muscle to 
the knee, where it pierces the fascia lata, communicates with the long saphenous 
nerve, and gives off' several cutaneous branches. The nerve then passes down the 
inner side of the leg, to the integument of which it is distributed. This nerve, 
beneath the fascia lata, joins in a plexiform network by uniting with branches of 
the long saphenous and obturator nerves (Fig. 511). When the communicating 
branch from the latter nerve is large and continued to the integument of the leg, 
the inner branch of the internal cutaneous is small and terminates at the plexus, 
occasionally giving off' a few cutaneous filaments. 
This nerve before subdividing gives off' a few filaments which pierce the fascia 
lata, to supply the integument of the inner side of the thigh, accompanying the 
long saphenous vein. One of these filaments passes through the saphenous opening, 
a second becomes subcutaneous about the middle of the thigh, and a third pierces 
the fascia at its lower third. 
The long or internal saphenous nerve is the largest of the cutaneous branches 
of the anterior crural. It approaches the femoral artery where this vessel passes 
beneath the Sartorius, and lies on its outer side, beneath the aponeurotic covering 
of Hunter's canal, as far as the opening in the lower part of the Adductor magnus. 
It then quits the artery and descends vertically along the inner side of the knee 
beneath the Sartorius, pierces the deep fascia between the tendons of the Sartorius 
and Gracilis, and becomes subcutaneous. The nerve then passes along the inner 
side of the leg, accompanied by the internal saphenous vein, descends behind the 
internal border of the tibia, and at the lower third of the leg divides into two 
branches: one continues its course along the margin of the tibia, terminating at 
the inner ankle; the other passes in front of the ankle, and is distributed to the 
integument along the inner side of the foot as far as the great toe, communicating 
with the internal branch of the musculo-cutaneous nerve. 
Branches.-The long saphenous nerve about the middle of the thigh gives off a 
communicating branch which joins the plexus formed by the obdurator and inter- 
nal cutaneous nerves. 
At the inner side of the knee it gives off a large branch (n. cutaneus patella!) 
which pierces the Sartorius and fascia lata, and is distributed to the integument in 
front of the patella. This nerve communicates above the knee with the anterior 
branch of the internal cutaneous; belozv the knee with other branches of the long 
saphenous; and on the outer side of the joint with branches of the middle and 
external cutaneous nerves, forming a plexiform network, the plexus patelice. The 
cutaneous nerve of the patella is occasionally small, and terminates by joining the 
internal cutaneous, which supplies its place in front of the knee. 
Below the knee the branches of the long saphenous nerve are distributed to the 
integument of the front and inner side of the leg, communicating with the cutane- 
ous branches from the internal cutaneous or obturator nerve. 
The deep group of branches of the anterior crural nerve are muscular and 
articular. 
The muscular branches supply the Pectineus and all the muscles on the front 
of the thigh except the Tensor vaginae femoris, which is supplied from the superior 
gluteal nerve, and the Sartorius, which is supplied by filaments from the middle or 
internal cutaneous nerves. 
The branches to the Pectineus. usually two in number, pass inward behind the 
femoral vessels and enter the muscle on its anterior surface. 
The branch of the Rectus muscle enters its under surface high up. 
The branch of the Vastus externus, of large size, follows the course of the 
descending branch of the external circumflex artery to the lower part of the muscle. 
It gives off an articular filament to the knee-joint. 
The branches to the Vastus internus and Crureus enter the middle of those 
muscles, the one to the Vastus internus supplying a filament to the knee-joint. THE SACRAL AND COCCYGEAL NERVES. 
775 
The articular branches, two in number, supply the knee-joint. One, a long 
slender filament, is derived from the nerve to the Vastus externus. It penetrates 
the capsular ligament of the joint on its anterior aspect. The other is derived from 
the nerve to the Vastus internus. It descends along the internal intermuscular 
septum, accompanying the deep branch of the anastomotica magna artery, pierces 
the capsular ligament of the joint on its inner side, and supplies the synovial 
membrane. 
THE SACRAL AND COCCYGEAL NERVES. 
The sacral nerves are five in number on each side. The four upper ones pass 
from the sacral canal through the sacral foramina; the fifth, through the foramen 
between the sacrum and coccyx. 
The roots of origin of the upper sacral (and lumbar) nerves are the largest of 
all the spinal nerves, whilst those of the lowest sacral and coccygeal nerve are the 
smallest. 
The roots of these nerves are of very considerable length, being longer than those 
of any of the other spinal nerves, on account of the spinal cord not extending beyond 
the first lumbar vertebra. From their great length and the appearance they pre- 
sent in connection with the spinal cord the roots of origin of these nerves are called 
collectively the cauda equina. Each sacral and coccygeal nerve divides into two 
divisions, anterior and posterior. 
The posterior sacral nerves (Fig. 513) are small, diminish in size from above 
downward, and emerge, except the last, from the sacral canal by the posterior sacral 
foramina. 
The three upper ones are covered at their exit from the sacral canal by the Mul- 
tifidus spinae, and divide into external and internal branches. 
The internal branches are small and supply the Multifidus spinae. 
The external branches join with each other and with the last lumbar and fourth 
sacral nerves by means of communicating loops. These branches pass outward to 
the outer surface of the great sacro-sciatic ligament, where they form a second series 
of loops beneath the Gluteus maximus. Cutaneous branches from this second series 
of loops, usually three in number, pierce the Gluteus maximus-one near the pos- 
terior inferior spine of the ilium, another opposite the end of the sacrum, and the 
third midway between the other two. They supply the integument over the poste- 
rior part of the gluteal region. 
The two lower posterior sacral nerves are situated below the Multifidus spinae. 
They are of small size, and do not divide into internal and external branches, but 
join with each other and with the coccygeal nerve, so as to form loops on the back 
of the sacrum, filaments from which supply the integument over the coccyx. 
The coccygeal nerve divides into its anterior and posterior divisions in the 
spinal canal. The posterior division is the smaller. It does not divide, but 
receives, as already mentioned, a communicating branch from the last sacral, 
and is lost in the fibrous structure on the back of the coccyx. 
The anterior sacral nerves diminish in size from above downward. The four 
upper ones emerge from the anterior sacral foramina: the anterior division of the 
fifth, after emerging from the spinal canal through its terminal opening, curves for- 
ward between the sacrum and the coccyx. All the anterior sacral nerves communi- 
cate with the sacral ganglia of the sympathetic at their exit from the sacral foram- 
ina. The first nerve, of large size, unites with the lumbo-sacral cord formed by 
the fifth lumbar and a branch from the fourth. The second, equal in size to the 
preceding, and the third, about one-fourth the size of the second, unite with this 
trunk, and form, with a small fasciculus from the fourth, the sacral plexus, a vesical 
branch being given off' from the third nerve to the bladder. 
The fourth anterior sacral nerve sends a branch to join the sacral plexus. 
The remaining portion of the nerve divides into visceral and muscular branches, 
and a communicating filament descends to join the fifth sacral nerve. The visceral 776 
THE SPINAL NERVES. 
branches are .distributed to the viscera of the pelvis, communicating with the sym- 
pathetic nerve. These branches ascend upon the rectum and bladder-in the 
female upon the vagina and bladder-communicating with branches of the sympa- 
thetic to form the hypogastric plexus. The muscular branches are distributed to 
the Levator ani, Coccygeus, and Sphincter ani. Cutaneous filaments hrise from 
the latter branch, which supply the integument between the anus and coccyx. 
Another cutaneous branch is frequently given off from this nerve, though some- 
times from the pudic (Schwalbe). It perforates the great sacro-sciatic ligament, 
and, winding round the lower border of the Gluteus maximus, supplies the skin 
over the lower and inner part of this .muscle. 
The fifth anterior sacral nerve, after passing from the lower end of the sacral 
canal, curves forward through the fifth sacral foramen, formed between the lower 
Fig. 513. 
The Posterior Sacral Nerves. 
part of the sacrum and the transverse process of the first piece of the coccyx. It 
pierces the Coccygeus muscle, and descends upon its anterior surface to the tip of 
the coccyx, where it again perforates the muscle, to be distributed to the integu- 
ment over the back part and side of the coccyx. This nerve communicates above 
with the fourth sacral and below with the coccygeal nerve, and supplies the Coc- 
cygeus muscle. 
The anterior division of the coccygeal nerve is a delicate filament which 
escapes at the termination of the sacral canal; it passes downward behind the 
rudimentary transverse process of the first piece of the coccyx, and curves forward, 
through the notch between the first and second pieces, piercing the Coccygeus mus- 
cle and descending on its anterior surface to near the tip of the coccyx, where it 
again pierces the muscle, to be distributed to the integument over the back part 
and side of the coccyx. It is joined by a branch from the fifth anterior sacral as 
it descends on the surface of the Coccygeus muscle. SACRAL PLEXUS. 
777 
Sacral Plexus (Fig. 514). 
The sacral plexus is formed by the lumbo-sacral cord, the anterior divisions of 
the three upper sacral nerves, and part of that of the fourth. These nerves pro- 
ceed in different directions, the upper ones obliquely downward and outward, the 
Fig. 514. 
EXTERNAL 
ILIAC ARTERY'' 
BR. TO 
COCCYGEU3 
COCCYGEAL 
TO ir.BR-TO 
vat'Jranj sphincter ANI 
lower one nearly horizontally, and they all unite into a single broad, flat cord. 
The sacral plexus is triangular in form, its base corresponding with the exit of the 
nerves from the sacrum, its apex with the lower part of the great sacro-sciatic fora- 
men. It rests upon the anterior surface of the Pyriformis, and is covered in front 
by the pelvic fascia, which separates it from the sciatic and pudic branches of the 
internal iliac artery and from the viscera of the pelvis. 
The branches of the sacral plexus are- 
Side View of Pelvis, showing sacral plexus. 
Muscular. 
Superior gluteal. 
Pudic. 
Small sciatic. 
Great sciatic. 
The muscular branches supply the Pyriformis, Obturator internus, the two 
Gemelli, and the Quadratus femoris. The branch to the Pyriformis arises either 
from the plexus or from the upper sacral nerves before they enter the plexus: the 
branch to the Obturator internus arises at the junction of the lumbo-sacral and 
first sacral nerves; it passes out of the pelvis through the great sacro-sciatic fora- 
men, crosses behind the spine of the ischium, and enters the pelvis again through 
the lesser sacro-sciatic foramen to the inner surface of the Obturator internus. The 
branch of the Gemellus superior arises from the lower part of the plexus, near the 
pudic nerve; the small branch to the Gemellus inferior and Quadratus femoris also 
arises from the lower part of the plexus: it passes through the great sacro-sciatic 778 
THE SPINAL NERVES. 
foramen, and courses down beneath the Gemelli and tendon of the Obturator inter- 
nus, and supplies the muscles on their deep or anterior surface. . It gives off an 
articular branch to the hip-joint. This branch is occasionally derived from the 
upper part of the great sciatic nerve. 
The Superior Gluteal Nerve (Fig. 516) arises from the back part of the lumbo- 
sacral cord; it passes from the pelvis through the great sacro-sciatic foramen above 
the Pyriformis muscle, accompanied by the gluteal vessels, and divides into a supe- 
rior and an inferior branch. 
The superior branch follows the line of origin of the Gluteus minimus, and sup- 
plies it and the Gluteus medius. 
The inferior branch crosses obliquely between the Gluteus minimus and medius, 
distributing filaments to both these muscles, and terminates in the Tensor vaginae 
femoris, extending nearly to its lower end. 
The Pudic Nerve arises from the lower part of the sacral plexus, and leaves 
the pelvis, through the great sacro-sciatic foramen, below the Pyriformis. It then 
crosses the spine of the ischium and re-enters the pelvis through the lesser sacro- 
sciatic foramen. It accompanies the pudic vessels upward and forward along the 
outer wall of the ischio-rectal fossa, being contained in a sheath of the obturator 
fascia, and divides into two terminal branches, the perineal nerve and the dorsal 
nerve of the penis. Near its origin it gives off the inferior hemorrhoidal nerve. 
The inferior hemorrhoidal nerve is occasionally derived from the sacral plexus. 
It passes across the ischio-rectal fossa, with its accompanying vessels, toward the 
lower end of the rectum, and is distributed to the integument round the anus. 
Branches of this nerve communicate with the inferior pudendal and superficial 
perineal nerves at the fore part of the perineum. 
The perineal nerve, the inferior and larger of the two terminal branches of the 
pudic, is situated below the pudic artery. It accompanies the superficial perineal 
artery in the perineum, dividing into cutaneous and muscular branches. 
The cutaneous branches (superficial perineal) are two in number, posterior and 
anterior. The posterior branch passes to the fore part of the ischio-rectal fossa, dis- 
tributing filaments to the Sphincter ani and integument in front of the anus, which 
communicate with the inferior hemorrhoidal nerve; it then passes forward, with the 
anterior branch, to the back of the scrotum, communicating with the anterior branch 
and with the inferior pudendal. The anterior branch passes to the fore part of the 
ischio-rectal fossa in front of the preceding, and accompanies it to the scrotum and 
under part of the penis. This branch gives one or two filaments to the Levator ani. 
The muscular branches are distributed to the Transversus perinaei, Accelerator 
urinae, Erector penis, and Compressor urethrae. The nerve of the bulb supplies the 
corpus spongiosum; some of its filaments run for some distance on the surface before 
penetrating to the interior. 
The dorsal nerve of the penis is the superior division of the pudic nerve; it 
accompanies the pudic artery along the ramus of the ischium; piercing the poste- 
rior layer of the deep perineal fascia, it runs forward along the inner margin of the 
ramus of the pubes between the two layers of the deep fascia. It then pierces the 
anterior layer, and in company with the dorsal artery of the penis passes through 
the suspensory ligament, and, running forward, is distributed to the glans. On the 
penis this nerve gives off' a cutaneous branch which runs along the side of the 
organ; it is joined with branches of the sympathetic, and supplies the integument 
of the upper surface and sides of the penis and prepuce, giving a large branch to 
the corpus cavernosum. 
In the female the pudic nerve is distributed to the parts analogous to those in 
the male, its superior division terminating in the clitoris, its inferior in the external 
labia and perineum. 
The Small Sciatic Nerve (Fig. 516) supplies the integument of the perineum 
and back part of the thigh and leg, and one muscle, the Gluteus maximus. It is 
usually formed by the union of two branches which arise from the lower part of 
the sacral plexus. It issues from the pelvis through the great sacro-sciatic foramen SACRAL PLEXUS. 
779 
Fig. 515. 
Fig.516. 
Superior 
(lluleal 
hi.die. 
N.tz, OBTURATOR INT. 
Sciatic 
Inferior 
hidenddl 
Descending 
C id ancons 
Jntf rnal 
Popliteal 
Externa- t 
"Popliteal , o«i 
Eero nr a L 
-External 
jScip7zc]iou,& 
Posterior 
lilial 
Com munica/n& 
Eeronei 
Ucental* - 
Cutaneous Nerves of Lower Extremity, posterior 
view. 
1 In this diagram the External saphenous and Communicans peronei are not in their normal posi- 
tion. They have been displaced by the removal of the superficial muscles. 
Nerves of the Lower Extremity,1 posterior view. 780 
THE SPINAL NERVES. 
below the Pyriformis muscle, descends beneath the Gluteus maximus with the sciatic 
artery, and at the lower border of that muscle passes along the back part of the 
thigh, beneath the fascia lata, to the lower part of the popliteal region, where it 
pierces the fascia and becomes cutaneous. It then accompanies the external saphe- 
nous vein below the middle of the leg, its terminal filaments communicating with 
the external saphenous nerve. 
The branches of the small sciatic nerve are muscular (inferior gluteal) and cutaneous. 
The inferior gluteal1 consist of several large branches given off to the under 
surface of the Gluteus maximus near its lower part. 
The cutaneous branches consist of two' groups, internal and ascending. 
The internal cutaneous branches are distributed to the skin at the upper and inner 
side of the thigh on its posterior aspect. One branch, longer than the rest, the infe- 
rior pudendal, curves forward below the tuber ischii, pierces the fascia lata, and 
passes forward beneath the superficial fascia of the perineum to be distributed to 
the integument of the scrotum in the male and the labium in the female, communi- 
cating with the superficial perineal and inferior hemorrhoidal nerves. 
The ascending cutaneous branches consist of two or three filaments which turn 
upward round the lower border of the Gluteus maximus, to supply the integument 
covering its surface. One or two filaments occasionally descend along the outer side 
of the thigh, supplying the integument as far as the middle of that region. 
Two or three branches are given off from the lesser sciatic nerve as it descends 
beneath the fascia of the thigh; they supply the integument of the back part of 
the thigh, popliteal region, and upper part of the leg. 
The Great Sciatic Nerve (Fig. 516) supplies nearly the whole of the integu- 
ment of the leg, the muscles of the back of the thigh, and those of the leg and 
foot. It is the largest nervous cord in the body, measuring three-quarters of an 
inch in breadth, and is the continuation of the lower part of the sacral plexus. It 
passes out of the pelvis through the great sacro-sciatic foramen below the Pyriformis 
muscle. It descends between the trochanter major and tuberosity of the ischium, 
along the back part of the thigh to about its lower third, where it divides into two 
large branches, the internal and external popliteal nerves. 
This division may take place at any point between the sacral plexus and the 
lower third of the thigh. When the division occurs at the plexus, the two nerves 
descend together side by side, or they may be separated at their commencement by 
the interposition of part or the whole of the Pyriformis muscle. As the nerve 
descends along the back of the thigh, it rests at first upon the External rotator 
muscles in company with the small sciatic nerve and artery, being covered by the 
Gluteus maximus; lower down, it lies upon the Adductor magnus and is covered 
by the long head of the Biceps. [The great sciatic nerve is accessible for operation 
in the middle line of the thigh, just below the gluteo-femoral crease.] 
The branches of the nerve before its division are articular and muscular. 
The articular branches arise from the upper part of the nerve; they supply the 
hip-joint, perforating its fibrous capsule posteriorly. These branches are sometimes 
derived from the sacral plexus. 
The muscular branches are distributed to the flexors of the leg-viz. the Biceps, 
Semitendinosus, and Semimembranosus, and a branch to the Adductor magnus. 
These branches are given off beneath the Biceps muscle. 
The Internal Popliteal Nerve, the larger of the two terminal branches of the 
great sciatic, descends along the back part of the thigh, through the middle of the 
popliteal space, to the lower part of the Popliteus muscle, where it passes with the 
artery beneath the arch of the Soleus and becomes the posterior tibial. It lies at 
first very superficial, and at the outer side of, and some distance from, the popliteal 
vessels; opposite the knee-joint it is in close relation with the vessels and crosses 
to the inner side of the artery. 
1 Some authors describe this nerve as a separate branch of the sacral plexus, derived from the 
lumbo-sacral cord and the first and second sacral nerves. If this is so, it is, as a rule, very intimately 
connected with the small sciatic at its origin. SACRAL PLEXUS. 
781 
The branches of this nerve are the articular, muscular, and a cutaneous branch, 
the external or short saphenous nerve. 
The articular branches, usually three in number, supply the knee-joint; two of 
these branches accompany the superior and inferior internal articular arteries, and 
a third the azygos artery. 
The muscular branches, four or five in number, arise from the nerve as it lies 
between the two heads of the Gastrocnemius muscle; they supply that muscle, the 
Plantaris, Soleus, and Popliteus. The nerves which supply the Popliteus turn 
round its lower border and are distributed to its deep surface. 
The external or short saphenous nerve (communicans poplitei) descends between 
the two heads of the Gastrocnemius muscle, and about the middle of the back of 
the leg pierces the deep fascia, and receives a communicating branch (communicans 
peronei) from the external popliteal nerve (Pig. 515). The nerve then continues 
its course down the leg near the outer margin of the tendo Achillis, in company 
with the external saphenous vein, winds round the outer malleolus, and is distributed 
to the integument along the outer side of the foot and little toe, communicating on 
the dorsum of the foot with the musculo-cutaneous nerve. In the leg its branches 
communicate with those of the small sciatic. 
The Posterior Tibial Nerve (Fig. 516) commences at the lower border of the 
Popliteus muscle, and passes along the back part of the leg with the posterior tibial 
vessels to the interval between the inner malleolus and the heel, where it divides 
into the external and internal plantar nerves. It lies upon the deep muscles of the 
leg, and is covered in the upper part by the muscles of the calf, lower down by the 
skin and fascia. In the upper part of its course it lies to the inner side of the pos- 
terior tibial artery, but it soon crosses that ves- 
sel and lies to its outer side as far as the ankle. 
In the lower third of the leg it is placed parallel 
with the inner margin of the tendo Achillis. 
The branches of the posterior tibal nerve are 
muscular, plantar-cutaneous, and articular. 
The muscular branches arise either separately 
or by a common trunk from the upper part of the 
nerve. They supply the Tibialis posticus, Plexor 
longus digitorum, and Flexor longus pollicis mus- 
cles, the branch to the latter muscle accompany- 
ing the peroneal artery. 
The plantar-cutaneous branch perforates the 
internal annular ligament and supplies the in- 
tegument of the heel and inner side of the sole 
of the foot. 
The articular branch is given off just above 
the bifurcation of the nerve and supplies the 
ankle-joint. 
The Internal Plantar Nerve (Fig. 517), the 
larger of the two terminal branches of the pos- 
terior tibial, accompanies the internal plantar 
artery along the inner side of the foot. From 
its origin at the inner ankle it passes beneath 
the Abductor pollicis, and then forward between 
this muscle and the Flexor brevis digitorum, di- 
vides opposite the bases of the metatarsal bones 
into four digital branches, and communicates 
with the external plantar nerve. 
Branches.-In its course the internal plan- 
tar nerve gives off cutaneous branches which 
pierce the plantar fascia and supply the integument of the sole of the foot; muscular 
branches, which supply the Abductor pollicis and Flexor brevis digitorum; articu- 
Fig. 517. 
.Eacte'rnal 
[nternal 
Plantar 
Dee ft 
"Branch 
The. Plantar Nerves. 782 
THE SPINAL NEEVES. 
lar branches to the articulations of the tarsus and metatarsus; and four digital 
branches. These pass between the divisions of the plantar fascia in the clefts be- 
tween the toes, and are distributed in the following manner: supplies the inner 
border of the great toe, and sends a filament to the Flexor pollicis brevis muscle; 
the second bifurcates to supply the adjacent sides of the great and second toes, 
sending a filament to the first Lumbrical muscle; the third digital branch supplies 
the adjacent sides of the second and third toes and the second Lumbrical muscle; 
the fourth supplies the corresponding sides of the third and fourth toes and receives 
a communicating branch from the external plantar nerve. It will be observed that 
the distribution of these branches is precisely similar to that of the median nerve 
in the hand. Each digital nerve gives off cutaneous and articular filaments, and 
opposite the last phalanx sends a dorsal branch which supplies the structure round 
the nail, the continuation of the nerve being distributed to the ball of the toe. 
The External Plantar Nerve, the smaller of the two, completes the nervous sup- 
ply to the structures of the foot, being distributed to the little toe and one-half of 
the fourth, as well as to most of the deep muscles, its distribution being similar to 
that of the ulnar in the hand. It passes obliquely forward with the external plan- 
tar artery to the outer side of the foot, lying between the Flexor brevis digitorum 
and Flexor accessorius, and in the interval between the former muscle and Abductor 
minimi digiti divides into a superficial and a deep branch. Before its division it 
supplies the Flexor accessorius and Abductor minimi digiti. 
The superficial branch separates into two digital nerves: one, the smaller of the 
two, supplies the outer side of the little toe, the Flexor brevis minimi digiti, and the 
two Interosseous muscles of the fourth metatarsal space; the other and larger digital 
branch supplies the adjoining sides of the fourth and fifth toes and communicates 
with the internal plantar nerve. 
The deep or muscular branch accompanies the external plantar artery into the 
deep part of the sole of the foot, beneath the tendons of the Flexor muscles and 
Adductor pollicis, and supplies all the Interossei (except those in the fourth meta- 
tarsal space), the two outer Lumbricales, the Adductor pollicis, and the Trans- 
versus pedis. 
The External Popliteal or Peroneal Nerve (Fig. 516), about one-half the size 
of the internal popliteal, descends obliquely along the outer sides of the popliteal 
space to the fibula, close to the inner margin of the Biceps muscle. It is easily felt 
beneath the skin behind the head of the fibula at the inner side of the tendon of 
the Biceps. [In tenotomy of the Biceps great care must be taken not to divide this 
nerve. The knife-blade is introduced flatwise between the tendon and the nerve and 
parallel to both of them. Its edge is then turned toward the tendon and its back 
toward the nerve.] About an inch below the head of the fibula it pierces the origin 
of the Peroneus longus, and divides beneath that muscle into the anterior tibial and 
musculo-cutaneous nerves. 
The branches of the peroneal nerve previous to its division are articular and 
cutaneous. 
The articular branches, two in number, accompany the superior and inferior 
external articular arteries to the outer side of the knee. The upper one occasion- 
ally arises from the great sciatic nerve before its bifurcation. A third {recurrent) 
articular nerve is given off at the point of division of the peroneal nerve; it ascends 
with the tibial recurrent artery through the Tibialis anticus muscle to the front of 
the knee, which it supplies. 
The cutaneous branches, two or three in number, supply the integument along 
the back part and outer side of the leg as far as its middle or lower part; one of 
these, larger than the rest, the communicans peronei, arises near the head of the 
fibula, crosses the external head of the Gastrocnemius to the middle of the leg, and 
joins with the external saphenous. This nerve occasionally exists as a separate 
branch which is continued down as far as the heel. 
The Anterior Tibial Nerve (Fig. 511, p. 771) commences at the bifurcation of 
the peroneal nerve, between the fibula and upper part of the Peroneus longus, passes SACRAL PLEXUS. 
783 
obliquely forward beneath the Extensor longus digitorum to the fore part of the 
interosseous membrane, and reaches the outer side of the anterior tibial artery 
above the middle of the leg; it then descends with the artery to the front of the 
ankle-joint, where it divides into an external and an internal branch. This nerve 
lies at first on the outer side of the anterior tibial artery, then in front of it, and 
again at its outer side at the ankle-joint. 
The branches of the anterior tibial nerve in its course through the leg are the 
muscular nerves to the Tibialis anticus, Extensor longus digitorum, Peroneus tertius, 
and Extensor proprius pollicis muscles, and an articular branch to the ankle-joint. 
The external or tarsal branch of the anterior tibial passes outward across the 
tarsus, beneath the Extensor brevis digitorum, and, having become ganglionic like 
the posterior interosseous nerve at the wrist, supplies the Extensor brevis digitorum 
and the articulations of the tarsus and metatarsus. 
The internal branch, the continuation of the nerve, accompanies the dorsalis 
pedis artery along the inner side of the dorsum of the foot, and at the first inter- 
osseous space divides into two branches, which supply the adjacent sides of the 
great ancl second toes, communicating with the internal division of the musculo- 
cutaneous nerve. 
The Musculo-cutaneous Nerve (Fig. 513, p. 776) supplies the muscles on the 
fibular side of the leg and the integument of the dorsum of the foot. It passes for- 
ward between the Peronei muscles and the Extensor longus digitorum, pierces the 
deep fascia at the lower third of the leg on its front and outer side, and divides into 
two branches. This nerve in its course between the muscles gives off muscular 
branches to the Peroneus longus and brevis and cutaneous filaments to the integu- 
ment of the lower part of the leg. 
The internal branch of the musculo-cutaneous nerve passes in front of the ankle- 
joint and along the dorsum of the foot, supplying the inner side of the great toe 
and the adjoining sides of the second and third toes. It also supplies the integu- 
ment of the inner ankle and inner side of the foot, communicating with the internal 
saphenous nerve, and joins with the anterior tibial nerve, between the great and 
second toes. 
The external branch, the larger, passes along the outer side of the dorsum of the 
foot, to be distributed to the adjoining sides of the third, fourth, and fifth toes. It 
also supplies the integument of the outer ankle and outer side of the foot, commu- 
nicating with the short saphenous nerve. 
The distribution of these branches of the musculo-cutaneous nerve will be found 
to vary; together they supply all the toes excepting the outer side of the little toe 
and the adjoining sides of the great and second toes, the former being supplied by 
the external saphenous, and the latter by the internal branch of the anterior tibial. 
[The popliteal nerves are easily accessible for operation in their respective posi- 
tions in the ham. The anterior and posterior tibial nerves can be reached by the 
same operations as the corresponding arteries.] The Sympathetic Nerve. 
THE Sympathetic Nervous System consists of (1) a series of ganglia connected 
I together by intervening cords, extending on each side of the vertebral column 
from the base of the skull to the coccyx; (2) of three great gangliated plexuses or 
aggregations of nerves and ganglia situated in front of the spine in the thoracic, 
abdominal, and pelvic cavities respectively; (3) of smaller ganglia situated in rela- 
tion with the abdominal [and other] viscera; and (4) of numerous nerve-fibres. 
These latter are of two kinds: communicating, by which the ganglia communicate 
with each other and with the cerebro-spinal nerves; and distributary, supplying in 
general all the internal viscera and the coats of the blood-vessels. [By the blood- 
vessels the sympathetic reaches all parts of the body.] 
Each gangliated cord may be traced upward from the base of the skull into 
its cavity by an ascending branch which passes through the carotid canal, forms a 
plexus on the internal carotid artery, and communicates with the ganglia on the 
first and second divisions of the fifth nerve. According to some anatomists, the 
two cords are joined at their cephalic extremities by these ascending branches, com- 
municating in a small ganglion (the ganglion of Kibes') situated upon the anterior 
communicating artery. The ganglia of these cords are distinguished as cervical, 
dorsal, lumbar, and sacral, and except in the neck they correspond pretty nearly in 
number to the vertebrae against which they lie. They may be thus arranged: 
Cervical portion ... 3 pairs of ganglia. 
Dorsal " . 12 " " 
Lumbar " . . . 4 " " 
Sacral " . . . 5 " " 
In the neck they are situated in front of the transverse processes of the verte- 
brae ; in the dorsal region, in front of the heads of the ribs; in the lumbar region, 
on the sides of the bodies of the vertebrae; and in the sacral region, in front of the 
sacrum. As the two cords pass into the pelvis they converge and unite together in 
a single ganglion {ganglion imp ar) placed in front of the coccyx. Each ganglion 
may be regarded as a distinct centre, and in addition to its branches of distribution 
possesses also branches of communication which communicate with other ganglia 
and with the cerebro-spinal nerves. 
The branches of communication between the ganglia are composed of gray and 
white nerve-fibres, the latter being continuous with those fibres of the spinal nerves 
which pass to the ganglia. 
The branches of communication between the ganglia and the cerebro-spinal 
nerves also consist of a white and gray portion; the former proceeding from the 
spinal nerve to the ganglion, the latter passing from the ganglion to the spinal 
nerve, so that a double interchange takes place between the two systems. 
The three great gangliated plexuses are situated in front of the spine in the 
thoracic, abdominal, and pelvic regions, and are named, respectively, the cardiac, 
the solar or epigastric, and the hypogastric plexuses. They consist of collections of 
nerves and ganglia, the nerves being derived from the gangliated cords and from 
the cerebro-spinal nerves. They distribute branches to the viscera. 
Smaller ganglia are also found lying amidst the nerves, some of them of micro- 
scopic size, in certain viscera; as, for instance, in the heart, the stomach, and the 
uterus. They serve as additional centres for the origin of nerve-fibres. 
The branches of distribution derived from the gangliated cords, from the prae- 
vertebral plexuses, and also from the smaller ganglia are principally destined for 
the blood-vessels and thoracic and abdominal viscera, supplying the involuntary 
784 THE SYMPATHETIC NERVE. 
785 
muscular fibre of the coats of the vessels and the hollow viscera and the secreting 
cells, as well as the muscular coats of the vessels in the glandular viscera. 
The Superior Cervical Ganglion. 
TC to I VC, Branches of communication to four upper 
cervical nerves. 
PS, Branches of communication to petrosal 
ganglion. 
V r, Branches of communication to ganglion 
of root of pneumogastric. 
V', Branches of communication to ganglion 
of trunk of pneumogastric. 
H, Branches of communication to hypoglossal 
nerve. 
CP, Carotid plexus. 
C'P', Cavernous plexus. 
CA, Branches accompanying internal carotid 
artery. 
OG, Branches to ophthalmic ganglion. 
tp, To tympanic branch of glosso-pharyngeal. 
3, to third nerve. 
4, to fourth nerve. 
5, to fifth nerve. 
6, to sixth nerve. 
V, Vidian nerve to spheno-palatine ganglion. 
Sp, Large superficial petrosal from facial 
nerve. 
ECA, Accompanying branches of external 
carotid artery. 
PP, Pharyngeal plexus, formed by union with 
branches of vagus and glosso-pharyn- 
geal nerves. 
SC, Superior cardiac nerve. 
The Middle Cervical, or Thyroid Ganglion. 
IVC to VIC, Branches of communication with 
fourth, fifth, and sixth cervical nerves. 
IT, Inferior thyroid branches. 
MC, Middle cardiac nerve. 
rl, To recurrent laryngeal. 
The Inferior Cervical Ganglion. 
VIIC to VIIIC, Branches of communication with 
seventh and eighth cervical nerves. 
IC, Inferior cardiac nerve. 
CP, Cardiac plexus. 
GW, Ganglion of Wrisberg. 
LCP, Posterior, or left coronary plexus. 
RCP, Anterior, or right coronary plexus. 
CRL, Cardiac branches from pneumogas- 
tric or recurrent laryngeal nerves. 
RPP, To right anterior pulmonary 
plexus. 
LPP, To left anterior pulmonary plexus. 
ID to XIID, Branches of communication from the 
first to the twelfth dorsal nerves. 
a, a, To aorta, vertebrae, oesophagus, and poste- 
rior pulmonary plexus. 
GSN, Great splanchnic nerve. 
SSN, Small splanchnic nerve. 
ssn, Smallest splanchnic nerve. 
D, Diaphragm. 
PN, Phrenic nerve. 
SP, Epigastric, or solar plexus. 
CLP, Cceliac plexus. 
Cs, Cystic plexus. 
GSD, Gastro-duodenal plexus. 
CsP, Gastric or coronary plexus. 
My, Pyloric plexus. 
SpP, Splenic plexus. 
LGsE, Left gastro-epiploic plexus. 
Per, Pancreatic plexus. 
HpP, Hepatic plexus. 
V", Branches from pneumogastric. 
DmP, Diaphragmatic plexus. 
SG, Semilunar ganglion. 
SRnP, Suprarenal plexus. 
R))P, Renal plexus. 
SpP, Spermatic plexus. 
SMP, Superior mesenteric plexus. 
Mee, Middle colic. 
Rce, Right colic. 
Ice, Ileo-colic. 
[Fig. 518.-Diagram of the Sympathetic Nerve. 
AP, Aortic plexus. 
IMP, Inferior mesenteric plexus. 
LCI, Left colic plexus. 
Sz, Sigmoid plexus. 
SHm, Superior hemorrhoidal plexus. 
IL to VL, Branches of communication with the five 
lumbar nerves. 
IS to VS, Branches of communication with the five 
sacral nerves. 
C, Branches of communication with the coccygeal 
nerve. 
HP, Hypogastric plexus. 
1HP, Pelvic, or inferior hypogastric plexus, 
giving branches to all the pelvic viscera 
(Flower).] 
In addition to these various divisions of the sympathetic, the ganglia connected 
with the three branches of the fifth cranial nerve are believed by some to con- 
stitute a part of the sympathetic system. These ganglia have already been 
described (p. 722 et seqq.). 786 
THE SYMPATHETIC NERVE. 
Fig. 519. 
Carotid riexltS\ 
Superior Cervical Ganglion- 
PTiari/rtqoal TJrancJies 
Middle Cervical Ganglion- 
Inferior Cervical Ganglion 
Cardiac JirS 
Peep Cardiac Plexus 
Superficial Cardiac Plexus 
Dorsal drr.nglia 
-Solar Plexus 
Aortic Plexus 
Lumbar Ganglia 
Hypogastric Pleooua 
Sacral 
Geuiglion Lugar- 
The Sympathetic Nerve. CERVICAL PORTION OF THE GANGLIATED CORD. 
787 
Cervical Portion of the Gangliated Cord. 
The cervical portion of the gangliated cord consists of three ganglia on each 
side, which are distinguished, according to their position, as the superior, middle, 
and inferior cervical. 
[Fig. 520. 
Cervical and Thoracic Portion of the Sympa- 
thetic. 
1. Two filaments from the facial, one to the 
spheno-palatine and the other to the otic 
ganglion. 
2. Nerve of Jacobson. 
3. Motor oculi externus. 
4. Right pneumogastric. 
5. Ophthalmic ganglion, receiving a motor fila- 
ment from the motor oculi communis and 
a sensory filament from the nasal branch 
of the fifth. 
5'. Spheno-palatine ganglion. 
5". Otic ganglion. 
5'". Branches from superior cervical ganglion 
to the carotid. 
6. Divided trunk of the sublingual. 
7. Lingual branch of the fifth nerve. 
8. Anterior branches of the upper four cervical 
nerves, sending filaments to the superior 
cervical sympathetic ganglion. 
9. Submaxillary ganglion. 
10. Spinal accessory. 
11. Superior laryngeal nerve. 
12. Glosso-pharyngeal. 
13. Superior laryngeal nerve. 
14. Superior cervical ganglion. 
15. Superior cardiac nerve. 
16. Chain of ganglia of the sympathetic. 
17. External laryngeal nerve. 
18. Anterior branches of the upper four cervical 
nerves, sending filaments to the superior 
cervical sympathetic ganglion. 
19. Recurrent laryngeal nerve. 
20. Cord connecting the superior and middle 
sympathetic ganglia. 
21. Middle cardiac nerve. 
22. Mntenor branches of the upper four cervical 
nerves, sending filaments to the superior 
cervical sympathetic ganglion. 
23. Right pneumogastric. 
24. Middle cervical ganglion. 
25. Filaments connecting inferior cervical gan- 
glion with the middle ganglion. 
26. Anterior branches of the fifth and sixth cer- 
vical nerve sending filaments to the middle 
cervical ganglion. 
27. Recurrent laryngeal nerve. 
28. Anterior branches of the seventh and eighth 
cervical and the first dorsal nerves, sending 
filaments to the inferior cervical ganglion. 
29. Inferior cardiac nerve. 
30. Anterior branches of the seventh and eighth 
cervical and the first dorsal nerves, sending 
filaments to the inferior cervical ganglion. 
31. Cardiac plexus. 
32. Filaments connecting inferior cervical gan- 
glion with the middle ganglion. 
33. Arch of the aorta. 
34. Inferior cervical ganglion. 
35. Ganglion of the cardiac plexus. 
36. Chain of ganglia of the sympathetic. 
37. Pulmonary artery. 
38. Intercostal nerves with their two filaments of 
communication with the thoracic ganglia. 
39. Cardiac plexus. 
40. Section of the. right bronchus. 
41. Nerve following the right coronary artery. 
42. Pulmonary artery. 
43. Right auricle. 
44. Right pneumogastric. 
45. Right ventricle. 
46. Intercostal nerves with their two filaments of 
communication with the thoracic ganglia. 
47. Right pneumogastric. 
48. Greai splanchnic nerve. 
49. Section of the Diaphragm. 
50. Great splanchnic nerve. 
51. Right pneumogastric. 
52. Section of the Diaphragm. 
53. Right half of the stomach. 
54. Chain of ganglia of the sympathetic. 
55. Left pneumogastric. 
56. Great splanchnic nerve. 
bl. Lower end of the phrenic nerve. 
58. Lesser splanchnic nerve. 
59. Solar plexus. 
60. Solar plexus (Sappey).] 
The Superior Cervical Gang-lion, the largest of the three, is placed opposite 
the second and third cervical vertebrse, and sometimes as low as the fourth or fifth. 788 
THE SYMPATHETIC NERVE. 
It is of a reddish-gray color and usually fusiform in shape; sometimes broad, and 
occasionally constricted at intervals, so as to give rise to the opinion that it consists 
of the coalescence of several smaller ganglia. It is in relation in front with the 
sheath of the internal carotid artery and internal jugular vein; behind it lies on 
the Rectus capitis anticus major muscle. 
Its branches may be divided into superior, inferior, external, internal, and 
anterior. 
The superior branch appears to be a direct continuation of the ganglion. It 
is soft in texture and of a reddish color. It ascends by the side of the internal 
[Fig. 521. 
Lumbar and Sacral Portions of the Sympa- 
thetic. 
1. Lower end of the right pneumogastric. 
2. Eleventh thoracic ganglion. 
3. Lower end of the left pneumogastric. 
4. Tenth dorsal nerve. 
5. Section of the Diaphragm. 
6. Twelfth thoracic ganglion. 
7. Lower end of the cesophagus. 
8. Lower end of the great splanchnic nerve. 
9. Left half of the stomach. 
10. Eleventh dorsal nerve. 
11. Solar plexus. 
12. Lower end of the lesser splanchnic nerve. 
13. Superior mesenteric plexus. 
14. First lumbar ganglion. 
15. lumbar plexus. 
16. Twelfth dorsal nerve. 
17. Small intestine. 
18. Branch from lumbar ganglion. 
19. Inferior mesenteric plexus. 
20. Branch from lumbar ganglion. 
21. Sigmoid flexure of the colon. 
22. Lumbar nerve. 
23. Rectum. 
24. Lumbar nerve. 
25. Bladder. 
26. Lumbar nerve. 
27. Prostate. 
28. 30. Lumbar nerves. 
32. Fourth lumbar ganglion. 
34, 36. Branches from the lumbar ganglia. 
38. Sacral nerve. 
40. Aortic lumbar plexus. 
42. Sacral portion of the sympathetic. 
44, 46. Aortic lumbar plexus. 
48. Hypogastric plexus. 
50.. Sacral nerves. 
52, 54, 56. Hypogastric plexus. 
58. Sacral portion of the sympathetic. 
60. Hypogastric plexus. 
62, 64. Sacral nerves. 
66. Hypogastric plexus (Sappey).] 
carotid artery, and, entering the carotid canal in the temporal bone, divides into 
two branches, which lie one on the outer and the other on the inner side of that 
vessel. 
The outer branch, the larger of the two, distributes filaments to the internal 
carotid artery and forms the carotid plexus. 
The inner branch also distributes filaments to the internal carotid, and, continu- 
ing onward, forms the cavernous plexus. CAVERNOUS PLEXUS. 
789 
Carotid Plexus. 
The carotid plexus is situated on the outer side of the internal carotid. Fila- 
ments from this plexus occasionally form a small gangliform swelling on the under 
surface of the artery, which is called the carotid ganglion. The carotid plexus 
communicates with the Gasserian ganglion, with the sixth nerve and the spheno- 
palatine ganglion, and distributes filaments to the wall of the carotid artery and 
to the dura mater (Valentin); while in the carotid canal it communicates with 
Jacobson's nerve, the tympanic branch of the glosso-pharyngeal. 
The communicating branches with the sixth nerve consist of one or two fila- 
ments which join that nerve as it lies upon the outer side of the internal carotid. 
Other filaments are also connected with the Gasserian ganglion. The communi- 
cation with the spheno-palatine ganglion is effected by a branch, the deep petrosal, 
which is given off from the plexus on the outer side of the artery, and which passes 
through the cartilage, filling up the foramen lacerum medium, and joins the great 
superficial petrosal to form the Vidian nerve. This nerve then proceeds along the 
pterygoid or Vidian canal to the spheno-palatine ganglion. The communication 
with Jacobson's nerve is effected by a branch which passes backward to join the 
tympanic plexus. 
Cavernous Plexus. 
The cavernous plexus is situated below and internal to that part of the internal 
carotid which is placed by the side of the sella Turcica in the cavernous sinus, and 
is formed chiefly by the internal division of the ascending branch from the superior 
cervical ganglion. It communicates with the third, fourth, fifth, and sixth nerves 
and with the ophthalmic ganglion, and distributes filaments to the wall of the inter- 
nal carotid. The branch of communication with the third nerve joins it at its 
point of division; the branch to the fourth nerve joins it as it lies on the outer 
wall of the cavernous sinus; other filaments are connected with the under surface 
of the trunk of the ophthalmic nerve; and a second filament of communication 
joins the sixth nerve. 
The filament of connection with the ophthalmic ganglion arises from the anterior 
part of the cavernous plexus; it accompanies the nasal nerve or continues forward 
as a separate branch. 
The terminal filaments from the carotid and cavernous plexuses are prolonged 
along the internal carotid, forming plexuses which entwine round the cerebral and 
ophthalmic arteries; along the former vessels they may be traced on to the pia 
mater, along the latter into the orbit, where they accompany each of the sub- 
divisions of the vessel, a separate plexus passing with the arteria centralis retinae 
into the interior of the eyeball. The filaments prolonged on to the anterior com- 
municating artery form a small ganglion, the ganglion of Ribes,1 which serves, as 
mentioned above, to connect the sympathetic nerves of the right and left sides. 
The inferior or descending- branch of the superior cervical ganglion communi- 
cates with the middle cervical ganglion. 
The external branches are numerous, and communicate with the cranial nerves 
and with the four upper spinal nerves. Sometimes the branch to the fourth 
spinal nerve may come from the cord connecting the upper and middle cervical 
ganglia. The branches of communication with the cranial nerves consist of 
delicate filaments which pass from the superior cervical ganglion to the ganglion 
of the trunk of the pneumogastric and to the twelfth nerve. A separate filament 
from the cervical ganglion subdivides and joins the petrosal ganglion of the glosso- 
pharyngeal and the ganglion of the root of the pneumogastric in the jugular 
foramen. 
The internal branches are three in number-the pharyngeal, laryngeal, and 
superior cardiac nerve. The pharyngeal branches pass inward to the side of the 
pharynx, where they join with branches from the pneumogastric, glosso-pharyngeal, 
1 The existence of this ganglion is doubted by some observers. 790 
THE SYMPATHETIC NERVE. 
and external laryngeal nerves to form the pharyngeal plexus. The laryngeal 
branches unite with the superior laryngeal nerve and its branches. 
The superior cardiac nerve (nervus superficialis cordis) arises by two or more 
branches from the superior cervical ganglion, and occasionally receives a filament 
from the cord of communication between the first and second cervical ganglia. It 
runs down the neck behind the common carotid artery, lying upon the Longus colli 
muscle, and crosses in front of the inferior thyroid artery and recurrent laryngeal 
nerve. 
The right superior cardiac nerve, at the root of the neck, passes either in front 
of or behind the subclavian artery, and along the arteria innominata to the back 
part of the arch of the aorta, where it joins the deep cardiac plexus. This nerve 
in its course is connected with other branches of the sympathetic; about the middle 
of the neck it receives filaments from the external laryngeal nerve; lower down 
one or two twigs from the pneumogastric; and as it enters the thorax it joins with 
the recurrent laryngeal. Filaments from this nerve communicate with the thyroid 
branches from the middle cervical ganglion and accompany these nerves to the thy- 
roid body. 
The left superior cardiac nerve, in the chest, runs by the side of the left 
carotid artery and in front of the arch of the aorta to the superficial cardiac 
plexus, but occasionally it passes behind the aorta and terminates in the deep 
cardiac plexus. 
The anterior branches ramify upon the external carotid artery and its 
branches, forming round each a delicate plexus, on the nerves composing which 
small ganglia are occasionally found. These ganglia have been named, according 
to their position, intercarotid1 (placed at the angle of bifurcation of the common 
carotid), lingual, temporal, and pharyngeal. The plexuses accompanying some of 
these arteries have important communications with other nerves. That surround- 
ing the external carotid is connected with the branch of the facial nerve to the 
Stylo-hyoid muscle; that surrounding the facial communicates with the submaxil- 
lary ganglion by one or two filaments; and that accompanying the middle m< n- 
geal artery sends offsets which pass to the otic ganglion and to the intumescentia 
gangliformis of the facial nerve (external petrosal). 
The Middle Cervical Ganglion (thyroid ganglion) is the smallest of the three 
cervical ganglia, and is occasionally altogether wanting. It is placed opposite the 
fifth cervical vertebra, usually upon or close to the inferior thyroid artery; hence 
the name "thyroid ganglion" assigned to it by Haller. 
Its superior branches ascend to communicate with the superior cervical 
ganglion. 
Its inferior branches descend to communicate with the inferior cervical 
ganglion. 
Its external branches pass outward to join the fifth and sixth spinal nerves. 
Those branches are not constantly found. 
Its internal branches are the thyroid and the middle cardiac nerve. 
The thyroid branches are small filaments which accompany the inferior thyroid 
artery to the thyroid gland; they communicate on the artery with the superior car- 
diac nerve, and in the gland with branches from the recurrent and external laryn- 
geal nerves. 
The middle cardiac nerve (nervus cardiacus magnus'), the largest of the three 
cardiac nerves, arises from the middle cervical ganglion or from the cord between 
the middle and inferior ganglia. On the right side it descends behind the common 
carotid artery, and at the root of the neck passes either in front of or behind the 
subclavian artery; it then descends on the trachea, receives a few filaments from 
the recurrent laryngeal nerve, and joins the deep cardiac plexus. In the neck it 
communicates with the superior cardiac and recurrent laryngeal nerves. On the left 
side the middle cardiac nerve enters the chest between the left carotid and subclavian 
arteries, and joins the left side of the deep cardiac plexus. 
1 This ganglion is of the same structure as the coccygeal gland (Luschka). THORACIC PORTION OF THE GANGLIATED CORD. 
791 
The Inferior Cervical Ganglion is situated between the base of the transverse 
process of the last cervical vertebra and the neck of the first rib, on the inner side 
of the superior intercostal artery. Its form is irregular; it is larger in size than the 
preceding and frequently joined with the first thoracic ganglion. 
Its superior branches communicate with the middle cervical ganglion. 
Its inferior branches descend, some in front of, others behind, the subclavian 
artery to join the first thoracic ganglion. The most important of these branches 
constitutes the inferior cardiac nerve. 
The inferior cardiac nerve (nervus cardiacus minor) arises from the inferior cer- 
vical or first thoracic ganglion. It passes down behind the subclavian artery and 
along the front of the trachea to join the deep cardiac plexus. It communicates 
freely behind the subclavian artery with the recurrent laryngeal and middle cardiac 
nerves. 
The external branches consist of several filaments, some of which communicate 
with the seventh and eighth spinal nerves; others accompany the vertebral artery 
along the vertebral canal, forming a plexus round the vessel, supplying it with fila- 
ments and communicating with the cervical spinal nerves as high as the fourth. 
Thoracic Portion of the Gangliated Cord. 
The thoracic portion of the gangliated cord consists of a series of ganglia which 
usually correspond in number to that of the vertebrae, but from the occasional coa- 
lescence of two their number is uncertain. These ganglia are placed on each side of 
the spine, resting against the heads of the ribs and covered by the pleura costalis: 
the last two are, however, anterior to the rest, being placed on the side of the bodies 
of the vertebrae. The ganglia are small in size and of a grayish color. The first, 
larger than the rest, is of an elongated form and usually blended with the last cervi- 
cal. They are connected together by cord-like prolongations from their substance. 
The external branches from each ganglion, usually two in number, communi- 
cate with each of the dorsal spinal nerves. 
The internal branches from the six upper ganglia are very small; they supply 
filaments to the thoracic aorta and its branches, besides small branches to the bodies 
of the vertebrae and their ligaments. Branches from the third and fourth ganglia 
form part of the posterior pulmonary plexus. 
The internal branches from the six lower ganglia are large and white in color; 
they distribute filaments to the aorta and unite to form the three splanchnic nerves. 
These are named the great, the lesser, and the smallest or renal splanchnic. 
The great splanchnic nerve is of a white color, firm in texture, and bears a 
marked contrast to the ganglionic nerves. It is formed by branches from the 
thoracic ganglia between the sixth and tenth, receiving filaments (according to Dr. 
Beck) from all the thoracic ganglia above the sixth. These roots unite to form a 
large round cord of considerable size. It descends obliquely inward in front of the 
bodies of the vertebrae along the posterior mediastinum, perforates the crus of the 
Diaphragm, and terminates in the semilunar ganglion, distributing filaments to the 
renal and suprarenal plexus. 
The lesser splanchnic nerve is formed by filaments from the tenth and eleventh 
ganglia and from the cord between them. It pierces the Diaphragm with the pre- 
ceding nerve, and joins the coeliac plexus. It communicates in the chest with the 
great splanchnic nerve, and occasionally sends filaments to the renal plexus. 
The smallest or renal splanchnic nerve arises from the last ganglion, and, piercing 
the Diaphragm, terminates in the renal plexus and lower part of the coeliac plexus. 
It occasionally communicates with the preceding nerve. 
A striking analogy appears to exist between the splanchnic and the cardiac nerves. 
The cardiac nerves are three in number: they arise from the three cervical ganglia, 
and are distributed to a large and important organ in the thoracic cavity. The 
splanchnic nerves, also three in number, are connected probably with all the dorsal 
ganglia, and are distributed to important organs in the abdominal cavity. 792 
THE SYMPATHETIC NERVE. 
The Lumbar Portion of the Gangliated Cord. 
The lumbar portion of the gangliated cord is situated in front of the vertebral 
column, along the inner margin of the Psoas muscle. It consists usually of four 
ganglia connected together by interganglionic cords. The ganglia are of small size, 
of a grayish color, shaped like a barleycorn, and placed much nearer the median line 
than the thoracic ganglia. 
The superior and inferior branches of the lumbar ganglia serve as communi- 
cating branches between the chain of ganglia in this region. They are usually single 
and of a white color. 
The external branches communicate with the lumbar spinal nerves. From the 
situation of the lumbar ganglia these branches are longer than in the other regions. 
They are usually two in number from each ganglion, and accompany the lumbar 
arteries around the sides of the bodies of the vertebrae, passing beneath the fibrous 
arches from which some of the fibres of the Psoas muscle arise. 
The internal branches pass inward in front of the aorta and form the aortic 
plexus. Other branches descend in front of the common iliac arteries, and join, 
over the promontory of the sacrum, to form the hypogastric plexus. Numerous 
delicate filaments are also distributed to the bodies of the vertebrae and the liga- 
ments connecting them. 
Pelvic Portion of the Gangliated Cord. 
The pelvic portion of the gangliated cord is situated in front of the sacrum, 
along the inner side of the anterior sacral foramina. It consists of four or five 
small ganglia on each side connected together by interganglionic cords. Below, 
these cords converge and unite on the front of the coccyx by means of a small gan- 
glion (the coccygeal ganglion or ganglion impar). 
The superior and inferior branches are the cords of communication between 
the ganglia above and below. 
The external branches, exceedingly short, communicate with the sacral nerves. 
They are two in number from each ganglion. The coccygeal nerve communicates 
either with the last sacral or coccygeal ganglion. 
The internal branches communicate, on the front of the sacrum, with the cor- 
responding branches from the opposite side; some, from the first two ganglia, pass 
to join the pelvic plexus, and others form a plexus which accompanies the middle 
sacral artery. 
THE GREAT PLEXUSES OF THE SYMPATHETIC. 
The Great Plexuses of the Sympathetic are the large aggregations of nerves and 
ganglia above alluded to, and situated in the thoracic, abdominal, and pelvic cavities 
respectively. From them are derived the branches which supply the viscera. 
The Cardiac Plexus. 
The cardiac plexus is situated at the base of the heart, and is divided into a 
superficial part, which lies in the concavity of the arch of the aorta, and a deep part, 
which lies between the trachea and aorta. 
The Great or Deep Cardiac Plexus (plexus magnus profundus, Scarpa) is 
situated in front of the trachea at its bifurcation, above the point of division of the 
pulmonary artery and behind the arch of the aorta. It is formed by the cardiac 
nerves derived from the cervical ganglia of the sympathetic and the cardiac branches 
of the recurrent laryngeal and pneumogastric. The only cardiac nerves which do 
not enter into the formation of this plexus are the left superior cardiac nerve and 
the left inferior cervical cardiac branch from the pneumogastric. The branches THE EPIGASTRIC OR SOLAR PLEXUS. 
793 
derived from the great cardiac plexus form the posterior coronary plexus and part 
of the anterior coronary plexus, whilst a few filaments proceed to the pulmonary 
plexuses and to the auricles of the heart. 
The branches from the rigid side of this plexus pass, some in front of, and others 
behind, the right pulmonary artery; the former, the more numerous, transmit a few 
filaments to the anterior pulmonary plexus, and are continued along the trunk of 
the pulmonary artery to form part of the anterior coronary plexus; those behind 
the pulmonary artery distribute a few filaments to the right auricle and form part 
of the posterior coronary plexus. 
The branches from the left side of the deep cardiac plexus distribute a few fila- 
ments to the left auricle of the heart and the anterior pulmonary plexus, and then 
pass on to form the greater part of the posterior coronary plexus, a few branches 
passing to the superficial cardiac plexus. 
The Superficial (Anterior) Cardiac Plexus lies beneath the arch of the aorta 
in front of the right pulmonary artery. It is formed by the left superior cardiac 
nerve, the left (and occasionally the right) inferior cervical cardiac branches of the 
pneumogastric, and filaments from the deep cardiac plexus. A small ganglion (car- 
diac ganglion of Wrisberg') is occasionally found connected with these nerves at their 
point of junction. This ganglion, when present, is situated immediately beneath the 
arch of the aorta on the right side of the ductus arteriosus. The superficial cardiac 
plexus forms the chief part of the anterior coronary plexus, and several filaments 
pass along the pulmonary artery to the left anterior pulmonary plexus. 
The posterior coronary plexus is chiefly formed by filaments prolonged from 
the left side of the deep cardiac plexus, and by a few from the right side. It sur- 
rounds the branches of the coronary artery at the back of the heart, and its fila- 
ments are distributed with those vessels to the muscular substance of the ventricles. 
The anterior coronary plexus is formed chiefly from the superficial cardiac 
plexus, but receives filaments from the deep cardiac plexus. Passing forward 
between the aorta and pulmonary artery, it accompanies the left coronary artery on 
the anterior surface of the heart. 
Valentin has described nervous filaments ramifying under the endocardium; and 
Remak has found in several Mammalia numerous small ganglia on the cardiac nerves, 
both on the surface of the heart and in its muscular substance. The elaborate dis- 
sections of the late Dr. Robert Lee have demonstrated without any doubt the exist- 
ence of a dense mesh of nerves, distributed both to the surface and in the substance 
of the heart, having numerous ganglia developed upon them Isimilar to those of the 
uterus (Fig. 522)]. 
The Epigastric or Solar Plexus. 
The Epigastric or Solar Plexus supplies all the viscera in the abdominal 
cavity. It consists of a great network of nerves and ganglia situated behind the 
stomach and in front of the aorta and crura of the Diaphragm. It surrounds the 
coeliac axis and root of the superior mesenteric artery, extending downward as low 
as the pancreas and outward to the suprarenal capsules. This plexus and the gan- 
glia connected with it receive the great splanchnic nerve of both sides and some 
filaments from the right pneumogastric. It distributes filaments which accom- 
pany, under the name of plexuses, all the branches from the front of the abdominal 
aorta. 
The semilunar ganglia of the solar plexus, two in number, one on each side, 
are the largest ganglia in the body. They are large, irregular gangliform masses 
formed by the aggregation of smallei' ganglia, having interspaces between them. 
They are situated in front of the crura of the Diaphragm, close to the suprarenal 
capsules: the one on the right side lies beneath the inferior vena cava; the upper 
part of each ganglion is joined by the greater splanchnic nerve, and to the inner 
side of each the branches of the solar plexus are connected. 
From the solar plexus are derived the following: 794 
THE SYMPATHETIC NERVE. 
Phrenic or diaphragmatic plexus. 
Suprarenal plexus. 
Renal plexus. 
Spermatic plexus. 
Coeliac plexus. 
Superior mesenteric plexus. 
Aortic plexus. 
The phrenic plexus accompanies the phrenic artery to the Diaphragm, which 
it supplies, some filaments passing to the suprarenal capsule. It arises from the 
upper part of the semilunar ganglion, and is larger on the right than on the left 
side. It receives one or two branches from the phrenic nerve. In connection with 
this plexus, on the right side, at its point of junction with the phrenic nerve, is a 
small ganglion (ganglion diaphragmaticum). This ganglion is placed on the under 
surface of the Diaphragm near the suprarenal capsule. Its branches are distributed 
to the inferior vena cava, suprarenal capsule, and the hepatic plexus. There is no 
ganglion on the left side. 
The suprarenal plexus is formed by branches from the solar plexus, from the 
semilunar ganglion, and from the phrenic and great splanchnic nerves, a ganglion 
being formed at the point of junction of the latter nerve. It supplies the supra- 
renal capsule. The branches of this plexus are remarkable for their large size in 
comparison with the size of the organ they supply. 
The renal plexus is formed by filaments from the solar plexus, the outer part 
of the semilunar ganglion, and the aortic plexus. It is also joined by filaments 
from the lesser and smallest splanchnic nerves. The nerves from these sources, 
fifteen or twenty in number, have numerous ganglia developed upon them. They 
accompany the branches of the renal artery into the kidney, some filaments on the 
right side being distributed to the inferior vena cava, and others to the spermatic 
plexus on both sides. 
The spermatic plexus is derived from the renal plexus, receiving branches from 
the aortic plexus. It accompanies the spermatic vessels to the testes. 
In the female the ovarian plexus is distributed to the ovaries and fundus of the 
uterus. 
The cceliac plexus, of large size, is a direct continuation from the solar 
plexus: it surrounds the cceliac axis and subdivides into the gastric, hepatic, and 
splenic plexuses. It receives branches from the lesser splanchnic nerves, and on 
the left side a filament from the right pneumogastric. 
The gastric or coronary plexus accompanies the gastric artery along the lesser 
curvature of the stomach and joins with branches from the left pneumogastric 
nerve. It is distributed to the stomach. 
The hepatic plexus, the largest offset from the cceliac plexus, receives filaments 
from the left pneumogastric and right phrenic nerves. It accompanies the hepatic 
artery, ramifying in the substance of the liver, upon its branches, and upon those 
of the vena portae. 
Branches from this plexus accompany all the divisions of the hepatic artery. 
Thus there is a 'pyloric plexus accompanying the pyloric branch of the hepatic 
which joins with the gastric plexus and pneumogastric nerves. There is also a 
gastro-duodenal plexus, which subdivides into the pancreatico-duodenal plexus, 
which accompanies the pancreatico-duodenal artery to supply the pancreas and 
duodenum, joining with branches from the mesenteric plexus ; and a gastro-epiploic 
plexus, which accompanies the right gastro-epiploic artery along the greater curva- 
ture of the stomach and anastomoses with branches from the splenic plexus. A 
cystic plexus, which supplies the gall-bladder, also arises from the hepatic plexus 
near the liver. 
The splenic plexus is formed by branches from the cceliac plexus, the left semi- 
lunar ganglia, and from the right pneumogastric nerve. It accompanies the splenic 
artery and its branches to the substance of the spleen, giving off in its course fila- 
ments to the pancreas (pancreatic plexus') and the left gastro-epiploic plexus, which 
accompanies the gastro-epiploica sinistra artery along the convex border of the 
stomach. THE EPIGASTRIC OR SOLAR PLEXUS. 
795 
Fig. 522. 
Ganglia and Nerves of the Gravid Uterus at the end of the Ninth Month (after Dr. R. Lee): a, the fundus and 
body of the uterus, having the peritoneum dissected off from the left side; b, the vagina, covered with 
nerves proceeding from the inferior border of the left hypogastric ganglion; c, the rectum; d, the left ova- 
rium and Fallopian tube; e, the trunk of the left spermatic vein and artery surrounded by the left spermatic 
ganglion; f, the aorta divided a little above the origin of the right spermatic artery, and about three inches 
above its division into the two common iliac arteries; g, the vena cava; h, trunk of the right spermatic 
vein entering the vena cava; i, right ureter; k, the two cords of the great sympathetic nerve, passing down 
along the front of the aorta; l, trunk of the inferior mesenteric artery, passing off from the aorta and cov- 
ered with a great plexus of nerves sent off from the left and right cords of the great sympathetic; m, m, the 
two cords of the great sympathetic, passing down below the bifurcation of the aorta to the point where they 
separate into the right and left hypogastric nerves; n, the right hypogastric nerve with its artery injected 
proceeding to the neck of the uterus, to terminate in the right hypogastric ganglion; o, the left hypogastric 
nerve where it is entering the left hypogastric ganglion and giving off branches to the left subperitoneal 
ganglion; p, hemorrhoidal nerves, accompanying the hemorrhoidal artery and proceeding from the great 
plexus which surrounds the inferior mesenteric artery; q, the sacral nerves, entering the whole outer sur- 
face of the hypogastric ganglion; r, the left hypogastric ganglion, with its arteries injected; s, the nerves 
of the vagina; t, nerves, with an injected artery proceeding from the upper part of the left hypogastric 
ganglion along the body of the uterus and terminating in the left spermatic ganglion: u, continuation of 
these nerves and the branches which they give off to the subperitoneal plexuses; v, the same nerves pass- 
ing upward beneath the subperitoneal plexuses, and anastomosing freely with them; w, the left spermatic 
ganglion, in which the nerves and artery from the hypogastric ganglion and the branches of the left sub- 
peritoneal plexuses terminate, and from which the nerves of the fundus uteri are supplied; x, the left sub- 
peritoneal plexuses covering the body of the uterus; y, the left subperitoneal ganglion, with numerous 
branches of nerves extending between it and the left hypogastric nerve and ganglion; z, the left common 
iliac artery cut across and turned aside, that the left hypogastric nerve and ganglion might be traced and 
exposed. 796 
THE SYMPATHETIC NERVE. 
The superior mesenteric plexus is a continuation of the lower part of the 
great solar plexus, receiving a branch from the junction of the right pneumogastric 
nerve with the coeliac plexus. It surrounds the superior mesenteric artery, which 
it accompanies into the mesentery, and divides into a number of secondary plex- 
uses which are distributed to all the parts supplied by the artery-viz. pancreatic 
branches to the pancreas; intestinal branches which supply the whole of the small 
intestine; and ileo-colic, right colic, and middle colic branches which supply the 
corresponding parts of the great intestine. The nerves composing this plexus are 
white in color and firm in texture, and have numerous ganglia developed upon them 
near their origin. 
The aortic plexus is formed by branches derived on each side from the semi- 
lunar ganglia and renal plexuses, receiving filaments from the solar plexus and 
some of the lumbar ganglia. It is situated upon the sides and front of the aorta, 
between the origins of the superior and inferior mesenteric arteries. From this 
plexus arise the inferior mesenteric, part of the spermatic, and the hypogastric 
plexuses, and it distributes filaments to the inferior vena cava. 
The inferior mesenteric plexus is derived chiefly from the left side of the aortic 
plexus. It surrounds the inferior mesenteric artery, and divides into a number of 
secondary plexuses, which are distributed to all the parts supplied by the artery- 
viz. the left colic and sigmoid plexuses, which supply the descending and sigmoid 
flexure of the colon, and the superior hemorrhoidal plexus, which supplies the upper 
part of the rectum and joins in the pelvis with branches from the left hypogastric 
plexus. 
Hypogastric Plexus. 
The Hypogastric Plexus supplies the viscera of the pelvic cavity. It is situ- 
ated in front of the promontory of the sacrum between the two common iliac arte- 
ries, and is formed by the union of numerous filaments which descend on each side 
from the aortic plexus and from the lumbar ganglia. This plexus contains no gan- 
glia, and bifurcates below into two lateral portions, which form the pelvic plexuses. 
Pelvic Plexus. 
The Pelvic Plexus (sometimes called inferior hypogastric) is situated at the side 
of the rectum and bladder in the male, and at the side of the rectum, vagina, and 
bladder in the female. It is formed by a continuation of the hypogastric plexus, 
by branches from the second, third, and fourth sacral nerves, and by a few fila- 
ments from the first two sacral ganglia. At the point of junction of these nerves 
small ganglia are found. From this plexus numerous branches are distributed to 
all the viscera of the pelvis. They accompany the branches of the internal iliac 
artery. 
The Inferior Hemorrhoidal Plexus arises from the back part of the pelvic 
plexus. It supplies the rectum, joining with branches of the superior hemor- 
rhoidal plexus. 
The Vesical Plexus arises from the fore part of the pelvic plexus. The nerves 
composing it are numerous and contain a large proportion of spinal nerve-fibres. 
They accompany the vesical arteries and are distributed at the side and base of the 
bladder. Numerous filaments also pass to the vesiculm seminales and vas deferens; 
those accompanying the vas deferens join, on the spermatic cord, with branches 
from the spermatic plexus. 
The Prostatic Plexus is continued from the lower part of the pelvic plexus. 
The nerves composing it are of large size. They are distributed to the prostate 
gland, vesiculae seminales, and erectile structure of the penis. The nerves supply- 
ing the erectile structure of the penis consist of two sets, the small and large cav- 
ernous nerves. They are slender filaments, which arise from the fore part of the 
prostatic plexus, and after joining with branches from the internal pudic nerve pass 
forward beneath the pubic arch. PELVIC PLEXUS. 
797 
The small cavernous nerves perforate the fibrous covering of the penis near its 
roots. 
The large cavernous nerve passes forward along the dorsum of the penis, joins 
with the dorsal branch of the pudic nerve, and is distributed to the corpus caver- 
nosum and spongiosum. 
The Vaginal Plexus arises from the lower part of the pelvic plexus. It is lost 
on the walls of the vagina, being distributed to the erectile tissue at its anterior 
part and to the mucous membrane. The nerves composing this plexus contain, like 
the vesical, a large proportion of spinal nerve-fibres. 
The Uterine Plexus arises from the upper part of the pelvic plexus, above the 
point where the branches from the sacral nerves join the plexus. Its branches 
accompany the uterine arteries to the side of the organ between the layers of the 
broad ligament, and are distributed to the cervix and lower part of the body of the 
uterus, penetrating its substance. 
Other filaments pass separately to the body of the uterus and Fallopian tube. 
Branches from the hypogastric plexus accompany the uterine arteries into the 
substance of the uterus. Upon these filaments ganglionic enlargements are found. 
(For a detailed account of the supply of nerves to the uterus, and for a description of the 
changes which these nerves and their ganglia undergo during pregnancy, the reader is referred 
to the papers on The Anatomy of the Nerves of the Uterus, published by Dr. Robert Lee. [A 
similar work has been published by the same author on the Nerves of the Heart f) Organs of Sense. 
THE organs of the senses are five in number-viz. those of touch, of taste, of 
smell, of hearing, and of sight. The skin, which is the principal seat of the 
sense of touch, has been described in the chapter on General Anatomy. 
THE TONGUE. 
The Tongue is the organ of the special sense of taste. It is situated in the 
floor of the mouth, in the interval between the two lateral portions of the body of 
the lower jaw. Its base or root is directed backward, and connected with the os 
Fig. 523. 
Til if or m 
Upper Surface of the Tongue. 
Fig. 524. 
Tuny ifo-rrn 
Sieonrfary 
fnth.il Ice 
CtrcumvalTate 
Art?' 
The Three Kinds of Papillae (magnified). 
hyoides by numerous muscles, with the epiglottis by three folds of mucous mem- 
brane which form the glosso-epiglottic ligaments, and with the soft palate by means 
798 THE TONGUE. 
799 
of the anterior pillars of the fauces. Its apex or tip, thin and narrow, is directed 
forward against the inner surface of the lower incisor teeth. The under surface of 
the tongue is connected with the lower j aw by the Genio-hyo-glossi muscles; from 
its sides the mucous membrane is reflected to the inner surface of the gums; and 
in front a distinct fold of that membrane, the fraenum linguce, is formed beneath 
its under surface. 
The tip of the tongue, part of the under surface, its sides, and dorsum are free. 
The dorsum of the tongue is convex, marked along the middle line by a raphe, 
which divides it into two symmetrical halves; this raphe terminates behind about 
half an inch from the base of the organ, a little in front of a depression, the fora- 
men ccecum. The anterior two-thirds of this surface are rough and covered with 
papillae; the posterior third is smoother and covered by the projecting orifices of 
numerous muciparous glands. 
The mucous membrane invests the entire extent of the free surface of the 
tongue. On the under surface of the organ it is thin and smooth, and may be 
traced on either side of the fraenum through the ducts of the submaxillary glands, 
and between the sides of the tongue and the lower jaw through the ducts of the 
sublingual glands. As it passes over the borders of the organ it gradually assumes 
its papillary character. 
Structure.-The mucous membrane of the tongue differs in structure in several 
respects from that of other parts. That covering the under surface of the organ is 
identical in structure with that lining the rest of the oral cavity. The mucous 
membrane on the anterior part of the dorsum of the tongue is thin and intimately 
adherent to the muscular tissue, whilst that at the root is much thicker and looser. 
It consists of a layer of connective tissue, the corium or mucosa, supporting numer- 
ous papillae, and covered, as well as the papillae, with epithelium. 
The corium consists of a dense network of fibrous connective tissue, with numer- 
ous elastic fibres, firmly connected with the fibrous tissue forming the septa between 
the muscular bundles of the tongue. It contains the ramifications of the numerous 
vessels and nerves from which the papillae are supplied, and large plexuses of lym- 
phatic vessels. 
The papillce consist of papillary projections of the corium, and like it are made 
up of fibrous connective tissue, which forms a matrix supporting a complex loop of 
capillary blood-vessels and covered with epithelium. 
The papillce of the tongue are thickly distributed over the anterior two-thirds of 
its upper surface, giving to it its characteristic roughness. The principal varieties 
are the papillae maximae (pircumvallatce'), papillae mediae and papillae 
minimae (conicce or filif'ormes). 
The papillce maximce (circumvallatae) are of large size and vary from eight to ten 
in number. They are situated at the back part of the dorsum of the tongue, near 
its base, forming a row on each side, which, running backward and inward, meet in 
the middle line like the two lines of the letter V inverted. Each papilla consists of 
a central flattened projection of mucous membrane, from to of an inch wide, 
attached to the bottom of a cup-shaped depression of the mucous membrane; the 
papilla is in shape like a truncated cone, the smaller end being directed downward 
and attached to the tongue, the broader part or base projecting on the surface and 
being studded with numerous small secondary papillae, which, however, are covered 
by a smooth layer of the epithelium. The cup-shaped depression forms a kind of 
fossa round the papilla, having a circular margin of about the same elevation cov- 
ered with smaller papillae. At the point of junction of the two rows of papillae is 
the deep depression, the foramen ccecum, mentioned above. 
The papillce medice (fungiformes), more numerous than the preceding, are scat- 
tered irregularly and sparingly over the dorsum of the tongue, but are found chiefly 
at its sides and apex. They are easily recognized among the other papillae by their 
large size, rounded eminences, and deep-red color. They are narrow at their attach- 
ment to the tongue, but broad and rounded at their free extremities, and covered with 
secondary papillae. Their epithelial investment is very thin. 800 
ORGANS OF SENSE. 
The papillce minimce (conicae or filiformes) cover the anterior two-thirds of the 
dorsum of the tongue. They are very minute, more or less conical or filiform in 
shape, and arranged in lines corresponding in direction with the two rows of the 
papillae circumvallatae, excepting at the apex of the organ, where their direction is 
transverse. They have projecting from their apices numerous filiform processes or 
secondary papillae, which are of a whitish tint, owing to the thickness and density 
of the epithelium of which they are composed, and which has here undergone a 
peculiar modification, the cells having become cornified and elongated into dense, 
imbricated, brush-like processes. They contain also a number of elastic fibres, 
which render them firmer and more elastic than the papillae of mucous membrane 
generally. 
Simple papillce, similar to those of the skin, are disposed very unequally among 
the compound forms, and exist sparingly on the surface of the tongue behind the 
circumvallate variety, buried under a layer of epithelium. 
Structure of the Papillae.-The papillae apparently resemble in structure those 
of the cutis, consisting of a cone-shaped projection of connective tissue covered with 
a thick layer of squamous epithelium, and contain one or more capillary loops, 
amongst which nerves are distributed in great abundance. If the epithelium is 
removed, it will be found that they are not simple elevations like the papillae of the 
skin, for the surface of each is studded with minute conical processes of the mucous 
membrane, which form secondary papillae (Todd and 
Bowman). In the papillae circumvallatae the nerves 
are numerous and of large size; in the papillae fun- 
giformes they are also numerous, and terminate in a 
plexiform network, from which brush-like branches 
proceed; in the papillae filiformes their mode of ter- 
mination is uncertain. Buried in the epidermis of 
the papillae circumvallatae and in some of the fungi- 
formes certain peculiar bodies called taste-goblets 
have been described.1 They are flask-like in shape, 
their broad base resting on the corium, and theii* 
neck opening by an orifice between the cells of the 
epithelium. They are formed by two kinds of cells: 
the exterior (cortical), which are arranged in several 
layers, being spindle-shaped and flattened, and in 
contact by their edges, the tapering extremities extending from the base to the apex 
of the organ. They thus enclose the central cells (gustatory cells), which are also 
spindle-shaped, but not flattened, and have a large spherical nucleus about the mid- 
dle of the cell. Both extremities are filamentous: the inner process is described 
as continuous with the terminal fibril of a nerve, while the outer one projects as an 
extremely fine hair through the orifice of the taste-goblet.2 
Besides the papillae, the mucous membrane of the tongue is provided with glands, 
and at the posterior part contains large quantities of lymphoid tissue. 
There are two varieties of glands present in the tongue, the mucous and serous. 
The mucous are similar in structure to the labial and buccal glands. They are 
found all over the surface of the mucous membrane of the tongue, except in the 
immediate vicinity of the taste-goblets; chiefly at the back, but also at the apex 
and marginal parts. In connection with these glands a special one has been 
described by Blandin and Nuhn. It is situated near the apex of the tongue on 
either side of the fraenum, and is covered over by a fasciculus of muscular fibre 
derived from the Stylo-glossus and Inferior lingualis. It is from half an inch to 
nearly an inch long, and about the third of an inch broad. It has from four to six 
orifices, which open on the under surface of the apex. 
The serous glands occur only at the back of the tongue in the neighborhood of 
Fig. 525. 
Taste-goblets: a, central cell; &, cortical 
cell. 
1 These bodies are also found in considerable numbers at the side of the base of the tongue, just 
in front of the anterior pillars of the fauces. 
2 See Engelmann, in Stricker's Handbook (New Syd. Soc. Trans.), vol. iii. p. 2. THE NOSE. 
801 
the taste-goblets, their ducts opening for the most part into the fossae of the circum- 
vallate papillae. These glands are racemose, the duct branching into several minute 
ducts, which terminate in alveoli lined by a single layer of more or less columnar 
epithelium. Their secretion is of a watery nature, and probably assists in the dis- 
tribution of the substance to be tasted over the taste-area (Ebner). 
The lymphoid tissue is situated, for the most part, at the back of the tongue, 
between the epiglottis and the circumvallate papillae, and is collected at numerous 
points into distinct masses known as follicles. Here and there in this situation are 
depressions in the mucous membrane surrounded by nodules of lymphoid tissue, 
similar to the structure found in the tonsil: into them open some of the ducts of 
the mucous glands. 
The epithelium is of the scaly variety, like that of the epidermis. It covers the 
free surface of the tongue, as may be easily demonstrated by maceration or boiling, 
when it can be detached entire; it is much thinner than in the skin: the intervals 
between the large papillae are not filled up by it, but each papilla has a separate 
investment from root to summit. The deepest cells may sometimes be detached as 
a separate layer, corresponding to the rete mucosum, but they never contain coloring 
matter. 
The tongue consists of two symmetrical halves, separated from each other in the 
middle line by a fibrous septum. Each half is composed of muscular fibres arranged 
in various directions, containing much interposed fat and supplied by vessels and 
nerves, and partly invested by mucous membrane and a submucous fibrous stratum. 
Into the latter the muscular fibres are inserted that pass to the surface. It is 
thicker behind than in front, and is continuous with the sheaths of the muscles 
attached to it. 
The fibrous septum consists of a vertical layer of fibrous tissue extending 
throughout the entire length of the middle line of the tongue from the base to 
the apex. It is thicker behind than in front, and occasionally contains a small 
fibro-cartilage about a quarter of an inch in length. It is well displayed by mak- 
ing a vertical section across the organ [Fig. 294, p. 391]. Another strong, fibrous 
lamina, termed the hypoglossal membrane, connects the under surface of the base 
of the tongue to the body of the hyoid bone. This membrane receives in front 
some of the fibres of the Genio-hyo-glossi. 
Each half of the tongue consists of extrinsic and intrinsic muscles. The former 
have been already described; they are the Hyo-glossus, Genio-hyo-glossus, Stylo- 
glossus, Palato-glossus, and part of the Superior constrictor. The intrinsic muscu- 
lar fibres are described along with the Lingualis on p. 391. 
The arteries of the tongue are derived from the lingual, the facial, and ascending 
pharyngeal. 
The nerves of the tongue are four in number in each half: the gustatory branch 
of the fifth, which is distributed to the papillae at the fore part and sides of the 
tongue; the lingual branch of the glosso-pharyngeal, which is distributed to the 
mucous membrane at the base and side of the tongue and to the papillae circum- 
vallatae; the hypoglossal nerve, which is distributed to the muscular substance of 
the tongue; and the chorda tympani, to the Lingualis muscle. The glosso-pharyn- 
geal branch is the special nerve of the sense of taste; the gustatory is the nerve of 
common sensation, and may possibly be concerned in the sense of taste; and the 
hypoglossal is the motor nerve of the tongue. 
THE NOSE. 
The nose is the special organ of the sense of smell: by means of the peculiar 
properties of its nerves it protects the lungs from the inhalation of deleterious gases 
and assists the organ of taste in discriminating the properties of food. 
The organ of smell consists of two parts-one external, the nose; the other 
internal, the nasal fossa;. 802 
ORGANS OF SENSE. 
The nose is the more anterior and prominent part of the organ of smell. It is 
of a triangular form, directed vertically downward, and projects from the centre of 
the face immediately above the upper lip. Its summit or root is connected directly 
with the forehead. Its inferior part, the base of the nose, presents two elliptical 
orifices, the nostrils, separated from each other by an antero-posterior septum, the 
columna. The margins of these orifices are provided with a number of stiff hairs, 
or vibrissce, which arrest the passage of foreign substances carried with the current 
of air intended for respiration. The lateral surfaces of the nose form by their union 
the dorsum, the direction of which varies considerably in different individuals. The 
dorsum terminates below in a rounded eminence, the lobe of the nose. 
The nose is composed of a framework of bones and cartilages, the latter being 
Fig. 526. 
Fro. 527. 
Seen from below 
Side Vteur 
-LowerL ate/ral 
C. 
Cartilages of the Nose. 
slightly acted upon by certain muscles. It is covered externally by the integument, 
internally by mucous membrane, and supplied with vessels and nerves. 
The bony framework occupies the upper part of the organ : it consists of the 
nasal bones and the nasal processes of the superior maxillary. 
The cartilaginous framezvork consists of five pieces-the two upper and the two> 
lower lateral cartilages, and the cartilage of the septum. 
The upper lateral cartilages are situated below the free margin of the nasal 
bones; each cartilage is flattened and triangular in shape. Its anterior margin is 
thicker than the posterior and connected with the fibro-cartilage of the septum. 
Its posterior margin is attached to the nasal process of the superior maxillary and 
nasal bones. Its inferior margin is connected by fibrous tissue with the lower 
lateral cartilage: one surface is turned outward, the other inward toward the nasal 
cavity. 
The lower lateral cartilages are two thin, flexible plates, situated immediately 
below the preceding, and bent upon themselves1 in such a manner as to form the 
inner and outer walls of each orifice of the nostril. The portion which forms the 
inner wall, thicker than the rest, is loosely connected with the same part of the 
opposite cartilage, and forms a small part of the columna. Its outer extremity, free, 
rounded, and projecting, forms, with the thickened integument and subjacent tissue, 
the lobe of the nose. The part which forms the outer wall is curved to correspond 
with the ala of the nose: it is oval and flattened, narrow behind, where it is con- 
[' Hence the bilobed tip of the nose in some persons, in whom the furrow between the two car- 
tilages is marked.] THE NOSE. 
803 
nected with the nasal process of the superior maxilla by a tough fibrous membrane 
in which are found three or four small cartilaginous plates (sesamoid cartilages)- 
cartilagines minores. Above it is connected to the upper lateral cartilage and front 
part of the cartilage of the septum; below it is separated from the margin of the 
nostril by dense cellular tissue; and in front it forms, with its fellow, the promi- 
nence of the tip of the nose. 
The cartilage of the septum is somewhat quadrilateral in form, thicker at its 
margins than at its centre, and completes the separation between the nasal fossae in 
front. Its anterior margin, thickest 
above, is connected from above down- 
ward with the nasal bones, the front 
part of the two upper lateral cartilages, 
and the inner portion of the two lower 
lateral cartilages. Its posterior margin 
is connected with the perpendicular la- 
mella of the ethmoid; its inferior mar- 
gin, with the vomer and the palate pro- 
cesses of the superior maxillary bones. 
These various cartilages are con- 
nected to each other and to the bones 
by a tough, fibrous membrane, the peri- 
chondrium, which allows the utmost fa- 
cility of movement between them. 
The muscles of the nose are situated 
immediately beneath the integument: 
they are (on each side) the Pyramidalis 
nasi, the Levator labii superioris alaeque 
nasi, the Dilatator naris, anterior and posterior, the Compressor nasi, the Compres- 
sor narium minor, and the Depressor alae nasi. They have been described above 
(p. 374)., 
The integument covering the dorsum and sides of the nose is thin and loosely 
connected with the subjacent parts; but where it forms the tip or lobe and the alae 
of the nose it is thicker and more firmly adherent. It is furnished with a large 
number of sebaceous follicles, the orifices of which are usually very distinct. 
The mucous membrane lining the interior of the nose is continuous with the skin 
externally and with that which lines the nasal fossae within. 
The arteries of the nose are the lateralis nasi from the facial, and the nasal artery 
of the septum from the superior coronary, which supplies the alae and septum, the 
sides and dorsum being supplied from the nasal branch of the ophthalmic and the 
infraorbital. 
The veins of the nose terminate in the facial and ophthalmic. 
The nerves of the nose are branches from the facial, infraorbital, and infratroch- 
lear, and a filament from the nasal branch of the ophthalmic. 
Fig. 528. 
Bones and Cartilages of Septum of Nose, right side. 
Nasal Fossje. 
The nasal fossae are two irregular cavities situated in the middle of the face and 
extending from before backward. They open in front by the two anterior nares, 
and terminate in the pharynx behind by the posterior nares. The boundaries of 
these cavities and the openings which are connected with them as they exist in the 
skeleton have been already described (pp. 215-219, Figs. 181-184). 
The mucous membrane lining the nasal fossae is called the pituitary, from the 
nature of its secretion, or Schneiderian, from Schneider, the first anatomist who 
showed that the secretion proceeded from the mucous membrane, and not, as was 
previously imagined, from the brain. It is intimately adherent to the periosteum 
or perichondrium, over which it lies. It is continuous externally with the skin 
through the anterior nares, and with the mucous membrane of the pharynx through 804 
ORGANS OF SENSE. 
the posterior nares. From the nasal fossae its continuity may be traced with the 
conjunctiva through the nasal duct and lachrymal canals; with the lining membrane 
of the tympanum and mastoid cells, through the Eustachian tube; and with the fron- 
tal, ethmoidal, and sphenoidal sinuses and the antrum of Highmore, through the 
several openings in the meatuses. The mucous membrane is thickest and most vas- 
cular over the turbinated bones. It is also thick over the septum, but in the inter- 
vals between the spongy bones and on the floor of the, nasal fossae it is very thin. 
Where it lines the various sinuses and the antrum of Highmore it is thin and pale. 
The epithelium differs in its character according to the functions of the part of 
the nose in which it is found. Near the orifice of the nostril, where common sensa- 
tion is chiefly or alone required, the epithelium is of the ordinary pavement or scaly 
variety. In the rest of the cavity, below the distribution of the olfactory nerves- 
i. e. in the respiratory portion of the nasal cavity-the epithelium is columnar and 
ciliated. This is the case also in the sinuses of the nose. In the olfactory region 
-i. e. the region in which the terminal filaments from the olfactory bulb are dis- 
tributed (see p. 716)-the epithelial cells are columnar and non-ciliated: their free 
surface presents a sharp outline, and their deep extremity is prolonged into a process 
which runs inward, branching to communicate with similar processes from neighbor- 
ing cells, so as to form a network in the deep part of the mucous membrane. Eying 
between them are cells (termed by Max Schultze olfactory cells) which consist of a 
nucleated body and two processes, of which one runs outward between the columnar 
epithelial cells and terminates at the level of the surface of the mucous membrane; 
the other (the deep) process runs inward, is frequently beaded like a nerve-fibre, 
and is believed by most observers to be in connection with one of the terminal fila- 
ments of the olfactory nerve. 
The mucous membrane is pigmented in the olfactory, but not in the other regions, 
being of a light-yellow color, at least in the white races.1 
This membrane is also provided with a nearly continuous layer of branched 
mucous glands, the ducts of which open upon its surface. They are most numerous 
at the middle and back parts of the nasal fossae and largest at the lower and back 
part of the septum. 
Owing to the great thickness of this membrane the nasal fossae are much nar- 
rower, and the turbinated bones, especially the lower ones, appear larger and more 
prominent, than in the skeleton. From the same circumstance also the various 
apertures communicating with the meatuses are either narrowed or completely 
closed. 
In the superior meatus the aperture of communication with the posterior ethmoi- 
dal cells is considerably diminished in size and the spheno-palatine foramen com- 
pletely covered in. 
In the middle meatus the opening of the infundibulum is partially hidden by a 
projecting fold of mucous membrane, and the orifice of the antrum is contracted to 
a small circular aperture much narrower than in the skeleton. 
In the inferior meatus the orifice of the nasal duct is partially hidden by either 
a single or double valvular mucous fold, and the anterior palatine canal either com- 
pletely closed in or a tubular cul-de-sac of mucous membrane is continued a short 
distance into it. 
In the roof the opening leading to the sphenoidal sinus is narrowed and the aper- 
tures in the cribriform plate of the ethmoid completely closed in. 
The arteries of the nasal fossce are the anterior and posterior ethmoidal, from the 
ophthalmic, which supply the ethmoidal cells, frontal sinuses, and roof of the nose; 
a minute twig from the small meningeal; the spheno-palatine, from the internal 
maxillary, which supplies the mucous membrane covering the spongy bones, the 
meatuses, and septum ; and the alveolar branch of the internal maxillary, which 
supplies the lining membrane of the antrum. The ramifications of these vessels 
1 An interesting speculation has been suggested by Dr. W. Ogle (Med.-Chir. Trans.,vol. liii. 277) 
as to the possible connection between the presence and abundance of this pigment and the perfection 
of the sense of smell. THE EYE. 
805 
form a close, plexiform network beneath and in the substance of the mucous mem- 
brane. 
The veins of the nasal fossce form a close network beneath the mucous membrane. 
They pass, some with the veins accompa- 
nying the spheno-palatine artery, through 
the spheno-palatine foramen, and others 
through the alveolar branch to join the 
facial vein; some accompany the eth- 
moidal arteries and terminate in the oph- 
thalmic vein; and, lastly, a few commu- 
nicate with the veins in the interior of 
the skull through the foramina in the 
cribriform plate of the ethmoid bone and 
the foramen caecum. 
The nerves are-the olfactory, the nasal 
branch of the ophthalmic, filaments from 
the anterior dental branch of the superior 
maxillary, the Vidian, naso-palatine, de- 
scending anterior palatine, and nasal 
branches of Meckel's ganglion. 
The olfactory, the special nerve of the 
sense of smell, is distributed over the 
upper third of the septum and over the surface of the superior and middle spongy 
bones. 
The nasal branch of the ophthalmic distributes filaments to the upper and ante- 
rior part of the septum and outer wall of the nasal fossae. 
Filaments from the anterior dental branch of the superior maxillary supply the 
inferior meatus and inferior turbinated bone. 
The Vidian nerve supplies the upper and back part of the septum and superior 
spongy bone, and the upper anterior nasal branches from the spheno-palatine gan- 
glion have a similar distribution. 
The naso-palatine nerve supplies the middle of the septum. 
The larger or anterior palatine nerve supplies the middle and lower. spongy 
bones. 
Fig. 529. 
Nerves of Septum of Nose, right side. 
THE EYE. 
[Dissection.-The student should procure a few fresh bullocks' or sheep's eyes, with the mus- 
cles, lids, etc. The muscles and adnexa should be dissected first, and then the ball. Sections 
also should be made both antero-posteriorly and transversely through the entire ball.] 
The eyeball is contained in the cavity of the orbit. In this situation it is securely 
protected from injury, whilst its position is such as to ensure the most extensive range 
of sight. It is acted upon by numerous muscles, by which it is capable of being 
directed to any part; supplied by vessels and nerves; and is additionally protected 
in front by several appendages, such as the eyebrow, eyelids, etc. [The muscles 
and the optic nerve have already been described at pp. 371 and 717.] 
The eyeball is imbedded in the fat of the orbit, but is surrounded by a thin 
membranous sac which isolates it, so as to allow of free movement. This mem- 
branous sac is named the capsule of Tenon or tunica vaginalis oculi. It may be 
regarded as a distinct serous membrane consisting of a parietal and visceral layer. 
The latter invests the posterior part of the globe from the ciliary margin of the 
cornea backward to the entrance of the optic nerve, and is connected to it by very 
delicate connective tissue ; the former (parietal) lines the hollow in the fat in which 
the eyeball is imbedded. Both layers are lined on their free surfaces by flattened 
endothelial cells. The cavity between them is continuous with the spaces between 
the different layers of the sheath of the optic nerve-that is to say, with the sub- 
arachnoidean between the pia matral and the arachnoid sheath, and the subdural 806 
ORGANS OF SENSE. 
between the arachnoid and dural sheath-and into it empty the lymphatic vessels 
of the sclerotic. The capsule is pierced by the muscles of the eyeball near their 
insertion, and sends tubular prolongations on them which become continuous with 
the sheath of the muscles. From the outer surface of these sheaths expansions, 
consisting of elastic fibres and muscle-cells, are given off' to the margin of the 
orbit, which serve to limit the degree of contraction of the muscles.1 
The eyeball is composed of segments of two spheres of different sizes. The 
anterior segment is one of a small sphere and forms about one-sixth of the eyeball. 
It is more prominent than the posterior segment, which is one of a much larger 
sphere and forms about five-sixths of the globe. The segment of the larger sphere 
is opaque, and formed by the sclerotic, the tunic of protection to the eyeball; the 
smaller sphere is transparent, and formed by the cornea. The axes of the eyeballs 
are nearly parallel, and do not correspond to the axes of the orbits, which are 
directed outward. The optic nerves follow' the direction of the axes of the orbits 
and entei' the eyeball a little to their inner or nasal side. The eyeball measures 
rather more in its transverse and vertical diameters than in its antero-posterior, the 
former diameters amounting to about an inch, the latter to about nine-tenths of an 
inch. 
The eyeball is composed of several investing tunics, and of fluid and solid refract- 
ing media called humors. 
The tunics are three in number : 
1. Sclerotic and Cornea. 
2. Choroid, Iris, and Ciliary Processes. 
3. Retina. 
The refracting media or humors are also three: 
Aqueous. 
Crystalline (lens) and Capsule. 
Vitreous. 
The sclerotic and cornea form the external tunic of the eyeball; they are essen- 
tially fibrous in structure, the sclerotic being opaque and forming the posterior five- 
sixths of the globe; the cornea, which forms the remaining sixth, being trans- 
parent. 
The Sclerotic hard) (Fig. 530) has received its name from its extreme 
density and hardness; it is a firm, unyielding, fibrous membrane, serving to main- 
tain the form of the globe. It is much thicker behind than in front. Its external 
surface is of a white color, quite smooth, except at the points where the Recti and 
Obliqui muscles are inserted into it, and covered for part of its extent by the 
conjunctival membrane, hence the whiteness and brilliancy of the front of the eye- 
ball. Its inner surface is stained of a brown color, marked by grooves, in which are 
lodged the ciliary nerves, and connected by an exceedingly fine cellular tissue (lam- 
ina fusca) with the outer surface of the choroid. Behind, it is pierced by the optic 
nerve a little to its inner or nasal side, and is continuous with the fibrous sheath of 
the nerve, which is derived from the dura mater. At the point where the optic 
nerve passes through tlie sclerotic this membrane forms a thin cribriform lamina 
(the lamina cribrosaf) ; the minute orifices in this layer serve for the transmission 
of the nervous filaments, and the fibrous septa dividing them from one another are 
continuous with the membranous processes which separate the bundles of nerve- 
fibres. One of these openings, larger than the rest, occupies the centre of the 
lamella; it is called the porus opticus, and transmits the arteria centralis retinae to 
the interior of the eyeball. Around the cribriform lamella are numerous small 
apertures for the transmission of the ciliary vessels and nerves. In front the scle- 
rotic is continuous with the cornea by direct continuity of tissue, but the opaque 
sclerotic overlaps the cornea rather more on its outer than on its inner surface. 
Structure.-The sclerotic is formed of white fibrous tissue intermixed with fine 
elastic fibres, and of flattened connective-tissue corpuscles, some of which are pig- 
mented, contained in cell-spaces between the fibres. These fibres are aggregated 
1 See a paper by Mr. C. B. Lockwood (Journal of Anatomy and Physiology, vol xx. Part I. p. 1). THE EYE. 
807 
into bundles which are arranged chiefly in a longitudinal direction. It yields gela- 
tin on boiling. Its vessels are not numerous, the capillaries being of small size, 
uniting at long and wide intervals. The existence of nerves in it is doubtful. 
The Cornea is the projecting transparent part of the external tunic of the eye- 
ball and forms the anterior sixth of the globe. It is not quite circular, being a 
little broader in the transverse than in the vertical direction, in consequence of the 
sclerotic overlapping the margin above and below. It is convex anteriorly, and 
projects forward from the sclerotic in the same manner that a watch-glass does from 
its case. Its degree of curvature varies in different individuals and in the same 
individual at different periods of life, it being more prominent in youth than in 
[Fig. 530. 
Cornea. 
Anterior Chamber 
Iris 
Canal of 
\Schleni m 
Posterior Chamber 
Ciliary Body 
Ciliary Processes. 
Crystalline Lens 
Canal oP 
Petit. 
CAVITY 0 CCUPICO 
BY VITREOUS HUMOR 
INTERNAL 
RECTUS 
MUSCLE 
Jletirwc 
Choroid coat. 
Sclerotic coat. 
Nerve sheath. 
' Optic Nerve 
Canal for central 
Artery 
Horizontal Section through the Left Eyeball (Allen).] 
advanced life, when it becomes flattened. The cornea is dense and of uniform 
thickness throughout; its posterior surface is perfectly circular in outline, and 
exceeds the anterior surface slightly in extent, from the latter being overlapped by 
the sclerotic. 
Structure.-The cornea consists of four layers-namely, (1) several strata of 
epithelial cells continuous with those of the conjunctiva; (2) a thick central fibrous 
structure, the cornea proper; (3) a homogeneous elastic lamina; and (4) a single 
layer of epithelial cells, forming part of the lining membrane of the anterior cham- 
ber of the eyeball. The name of membrane of Descemet or Demours is given to 
this posterior elastic lamina and its epithelial coating. 
The conjunctival epithelium, which covers the front of the cornea proper, consists 
of several strata of epithelial cells. The lowermost cells are columnar : then follow 
two or three layers of polyhedral cells, some of which present ridges and furrows 808 
ORGANS OF SENSE. 
similar to those found in the cuticle. Lastly, there are three or four layers of scaly 
epithelium with flattened nuclei. [This layer is very evident on scraping the cornea 
of a bullock's eye.] 
The proper substance of the cornea is fibrous, tough, unyielding, perfectly trans- 
parent, and continuous with the sclerotic, with which it is in structure identical. It 
is composed of about sixty flattened lamellae superimposed one on another. These 
lamellae are made up of bundles of fibrous connective tissue, the fibres of which are 
directly continuous with the fibres of the sclerotic. The fibres of each lamella are 
for the most part parallel with each other, those of alternating lamellae at right angles 
to each other. Fibres, however, frequently pass from one lamella to the next. 
The lamellae are connected with each other by an interstitial cement-substance, 
in which are spaces, the corneal sg>aces. The spaces are stellate in shape and have 
numerous offsets, by which they communicate with other spaces. Each space con- 
tains a cell, the corneal corpuscle, which resembles in form the space in which it is 
contained, but does not entirely fill it. 
Immediately beneath the conjunctival epithelium the cornea proper presents cer- 
tain characteristic differences which have led some anatomists to regard it as a dis- 
tinct membrane, and it has been named by Bowman the anterior elastic lamina. It 
differs, however- from the true elastic lamina or membrane of Descemet in many 
essential particulars, presenting evidence of fibrillar structure, and not having the 
same tendency to curl inward or to undergo fracture when detached from the other 
layers of the cornea. It consists of extremely closely interwoven fibrils similar to 
those found in the rest of the cornea proper, but contains no corneal corpuscles. It 
seems therefore more proper to regard it as a part of the proper tissue of the cornea.1 
The posterior elastic lamina, which covers the proper structure of the cornea 
behind, presents no structure recognizable under the microscope. It consists of a 
hard, elastic, and perfectly transparent homogeneous membrane of extreme thin- 
ness, which is not rendered opaque by either water, alcohol, or acids. It is very 
brittle, but its most remarkable properties are its extreme elasticity and the tendency 
which it presents to curl up or roll upon itself, with the attached surface innermost, 
when separate from the proper substance of the cornea. Its use appears to be (as 
suggested by Dr. Jacob) " to preserve the requisite permanent correct curvature of 
the flaccid cornea proper." 
The epithelial lining of the aqueous chamber covers the posterior surface of the 
posterior elastic lamina. It consists of a single layer of polygonal transparent 
nucleated cells similar to those found lining other serous cavities. 
Arteries and Nerves.-The cornea is a non-vascular structure, the capillary 
vessels terminating in loops at its circumference. Lymphatic vessels have not as yet 
been demonstrated in it, but are represented by the channels in which the bundles 
of nerves meet; these are lined by an endothelium and are continuous with the cell- 
spaces. The nerves are numerous, twenty-four to thirty-six in number (Kolliker), 
forty to forty-five (Waldeyer and Samisch); they are derived from the ciliary nerves 
and enter the laminated tissue of the cornea. They ramify throughout its substance 
in a delicate network, and their terminal filaments form a firm and closer plexus on 
the surface of the cornea proper beneath the epithelium. This is termed the sub epi- 
thelial plexus, and from it fibrils are given off' which ramify between the epithelial 
cells, forming a network which is termed the intra-epithelial plexus. 
Dissection.-In order to separate the sclerotic and cornea, so as to expose the second tunic, 
the eyeball should be immersed in a small vessel of water. A fold of the sclerotic near its ante- 
rior part having been pinched up-an operation not easily performed, from the extreme tension 
of the membrane-it should be divided with a pair of blunt-pointed scissors. As soon as the 
choroid is exposed, the end of a blowpipe should be introduced into the orifice and a stream of 
air forced into it, so as to separate the slight cellular connection between the sclerotic and cho- 
roid. [All this is needless trouble. A bullock's eye, which should be fresh, is tightly held in 
the left hand; the sclerotic then is carefully incised in the equator of the globe by repeated 
light cuts, till the black choroid is seen. One blade of a probe-pointed pair of scissors is now 
1 This layer has been called by Reichert the "anterior limiting layer"-a name which appears 
wore applicable to it than that of " anterior elastic lamina." THE EYE. 
809 
introduced flatwise between the sclerotic and choroid, hugging the sclerotic, and turned in the 
proper position, when the sclerotic is easily divided, a little at a time. It is not needful to put it in 
water or use the blowpipe.] The sclerotic should now be divided around its entire circumference 
[at the equator], and may be removed in separate portions. The front segment being then drawn 
forward, the handle of the scalpel should be pressed gently against it at its connection with the 
iris, and, the two being separated, a quantity of perfectly transparent fluid will escape ; this is the 
aqueous humor. In the course of the dissection the ciliary nerves may be seen lying in the loose 
cellular tissue between the choroid and sclerotic, or contained in delicate grooves on the inner 
surface of the latter membrane. 
Second Tunic.-This is formed by the choroid behind, the iris and ciliary pro- 
cesses in front, and by the ciliary ligament and Ciliary muscle at the point of junc- 
tion of the sclerotic and cornea. 
The choroid is the vascular and pigmentary tunic of the eyeball investing the 
posterior five-sixths of the globe, and extending as far forward as the cornea, the 
ciliary processes being appendages of 
the choroid developed from its inner 
surface in front. The iris is the cir- 
cular musculai' septum, which hangs 
vertically behind the cornea, present- 
ing in its centre a large circular aper- 
ture, the pupil. The ciliary ligament 
and Ciliary muscle form the white 
ring observed at the point where the 
choroid and iris join with each other 
and with the sclerotic and cornea. 
The Choroid is a thin, highly 
vascular membrane, of a dark-brown 
or chocolate color, which invests the 
posterior five-sixths of the central 
part of the globe. It is pierced be- 
hind by the optic nerve, and extends 
in front as far forward as the ciliary 
ligament, where it is connected with 
the iris and bends inward, forming 
on its inner surface a series of folds 
or plaitings, the ciliary processes. It 
is thicker behind than in front. Ex- 
ternally it is connected by a fine cel- 
lular web (membrana fusca) with the 
inner surface of the sclerotic. Its 
inner surface is smooth and lies in contact with the retina. 
Structure.-The choroid consists mainly of a dense capillary plexus, and of 
small arteries and veins carrying the blood to and returning it from this plexus. 
On its external surface-i. e. the surface next the sclerotic-is a thin membrane 
of fine elastic fibres arranged in lamellae, which are covered with endothelium and 
form spaces which communicate by perforations in the sclerotic, through which the 
vessels and nerves enter, with the capsule of Tenon. This layer is named the 
lamina suprachoroidea, and is continuous with the lamina fusca of the sclerotic. 
Internal to this is the choroid proper, and, in consequence of the small arteries 
and veins being arranged on the outer surface of the capillary network, it is cus- 
tomary to describe this as consisting of two layers, the outermost composed of small 
arteries and veins, with pigment-cells interspersed between them, and the inner con- 
sisting of a capillary plexus. The external layer consists, in part, of the larger 
branches of the short ciliary arteries which run forward between the veins before 
they bend downward to terminate in the capillaries, but is formed principally of 
veins, which are named, from their distribution, vence vorticosce. They converge to 
four or five equidistant trunks which pierce the sclerotic midway between the mar- 
gin of the cornea and the entrance of the optic nerve. Interspersed between the 
Fig. 531. 
The Choroid and Iris (enlarged). 810 
ORGANS OF SENSE. 
vessels are lodged dark star-shaped pigment-cells, the fibrous offsets from which, 
communicating with similar branchings from neighboring cells, form a delicate net- 
work or stroma which toward the 
inner surface of the choroid loses 
its pigmentary character. The in- 
ternal layer consists of an exceed- 
ingly fine capillary plexus formed 
by the short ciliary vessels, and is 
known as the tunica Ruyschiana. 
The network is close, and finer at 
the hinder part of the choroid than 
in front. About half an inch be- 
hind the cornea its meshes become 
larger, and are continuous with those 
of the ciliary processes. On the in- 
ner surface of this tunic is a very 
thin, structureless-or, according 
to Kolliker, faintly fibrous-mem- 
brane, called the lamina vitrea ; it 
is closely connected with the stroma 
of the choroid and separates it 
from the pigmentary layer of the 
retina. 
The ciliary processes should now be examined. They may be exposed either by detaching 
the iris from its connection with the ciliary ligament, or by making a transverse section of the 
globe and examining them from behind. 
The Ciliary processes are formed by the plaiting and folding inward of the vari- 
ous layers of the choroid (z. e. the choroid proper and the lamina vitrea) at its ante- 
rior margin, and are received between corresponding foldings of the suspensory liga- 
ment of the lens, thus establishing a communication between the choroid and inner 
tunic of the eye. They are arranged in a circle, and form a sort of plaited frill 
behind the iris round the margin of the lens. They vary between sixty and eighty 
in number, lie side by side, and may be divided into large and small; the latter, 
consisting of about one-third of the entire number, are situated in the spaces between 
the former, but without regular alternation. The larger processes are each about 
one-tenth of an inch in length and hemispherical in shape, their periphery being 
attached to the ciliary ligament and continuous with the layers of the choroid: the 
opposite margin is free and rests upon the circumference of the lens. Their ante- 
rior surface is turned toward the back of the iris, with the circumference of which 
they are continuous. The posterior surface is closely connected with the suspensory 
ligament of the lens. 
Structure.-The ciliary processes are similar in structure to the choroid : the 
vessels are larger, having chiefly a longitudinal direction. They are covered on 
their inner surface with a layer of black pigment-cells continuous with the cells of 
the pigmentary layer of the retina, and in their stroma are also other, stellate, 
pigment-cells, which, however, are not so numerous as in the choroid itself, and 
toward the free extremities of the folds are devoid of pigment. 
The Iris (iris, a rainbow) has received its name from its various colors in differ- 
ent individuals. It is a thin, circular-shaped, contractile curtain suspended in the 
aqueous humor behind the cornea and in front of the lens, being perforated a little 
to the nasal side of its centre by a circular aperture, the pupil, for the transmission 
of light. By its circumference it is intimately connected with the choroid; exter- 
nal to this is the ciliary ligament, by which it is connected to the sclerotic and 
cornea; its inner edge forms the margin of the pupil; its surfaces are flattened and 
look forward and backward, the anterior surface toward the cornea, the posterior 
toward the ciliary processes and lens. [The iris at the pupillary border is in con- 
Fig. 532. 
The Veins of the Choroid (enlarged). THE EYE. 
811 
tact with the lens (Fig. 530). Hence the readiness with which, in iritis, adhesions 
form between the iris and lens.] The circumference of the iris is connected to the 
cornea by a reticular structure 
denominated the lig amentum pec- 
tinatum iridis. This reticular 
structure is derived from the 
membrane of Descemet, which 
at the margin of the cornea 
breaks up into fibres; some of 
these are continued into the front 
of the iris, others are connected 
with the fore part of the choroid 
and sclerotic. These fibres form 
a reticulated structure at the outer 
angle of the anterior chamber, 
the intervals between the fibres 
forming small cavernous spaces 
(the spaces of Fontana). These 
little recesses communicate with 
a somewhat larger space in the 
substance of the sclerotic close 
to its junction with the cornea. 
This is the canal of Schlemm, or 
sinus circularis and according to Schwalbe and Waldeyer is a lymph-canal, 
but according to the more recent investigations of Leber is a venous sinus. The 
anterior surface of the iris is variously colored in different individuals, and marked 
by lines which converge toward the pupil. The posterior surface is of a deep purple 
tint, from being covered by dark pigment; it is hence named uvea, from its resem- 
blance in color to a ripe grape. 
Structure.-The iris is composed of the following structures: 
1. In front is a layer of polyhedral cells on a delicate hyaline basement- 
membrane. This layer is continuous with the epithelial layer of the membrane 
of Descemet, and in men with dark-colored irides the cells contain pigment- 
granules. 
2. Stroma.-The stroma consists of fibres and cells. The former are made up 
of fine delicate bundles of fibrous tissue, of which some few fibres have a circular 
direction at the circumference of the iris, but the chief mass consists of fibres radi- 
ating toward the pupil. They form, by their interlacement, a delicate mesh in 
which the vessels and nerves are contained. Interspersed between the bundles of 
connective tissue are numerous branched cells with fine processes. Many of them 
in dark eyes contain pigment-granules, but in blue eyes and the pink eyes of 
albinos they are unpigmented. 
3. The muscular fibre is involuntary, and consists of circular and radiating 
fibres. The circular fibres (sphincter of the pupil) surround the margin of the 
pupil on the posterior surface of the iris like a sphincter, forming a narrow band 
about one-thirtieth of an inch in width, those near the free margin being closely 
aggregated, those more external somewhat separated and forming less complete 
circles. The radiating fibres (dilator of the pupil) converge from the circum- 
ference toward the centre, and blend with the circular fibres near the margin of 
the pupil. 
4. Pigment.-The situation of the pigment-cells differs in different irides. In 
the various shades of blue eyes the only pigment-cells are several layers of small 
round or polyhedral cells filled with dark pigment, situated on the posterior surface 
of the iris and continuous with the pigmentary covering of the ciliary processes. 
The color of the eye in these individuals is due to this coloring-matter showing more 
or less through the texture of the iris. In the albino even this pigment is absent. 
In the gray, brown, and black eye there are, as mentioned above, pigment-granules 
Fig. 533. 
A n ter cor 
Cilia ry A? 
Short 
Ciliary Aji 
.Anterior 
C 
The Arteries of the Choroid and Iris: the sclerotic has been mostly 
removed (enlarged). 812 
ORGANS OF SENSE. 
to be found in the cells of the stroma and in the epithelial layer on the front of the 
iris, to which the color of the eye is due. 
The arteries of the iris are derived from the long and anterior ciliary and from 
the vessels of the ciliary processes. (See p. 532.) 
The nerves of the iris are derived from the ciliary branches of the lenticular 
ganglion and the long ciliary from the nasal branch of the ophthalmic division of 
the fifth. After reaching the iris in the manner described above (p. 723) they form 
a plexus around the attached margin of the iris; from this are derived non-medul- 
lated fibres which terminate in the circular and radiating muscular fibres. Their 
exact mode of termination has not been ascertained. Other fibres from the plexus 
terminate in a network on the anterior surface of the iris. The fibres derived from 
the motor root of the lenticular ganglion (third nerve) supply the circular fibres, 
while those derived from the sympathetic supply the radiating fibres. 
Membrana Papillaris.-In the foetus the pupil is closed by a delicate, trans- 
parent vascular membrane, the membrana papillaris, which divides the space into 
which the iris is suspended into two distinct chambers. This membrane contains 
numerous minute vessels continued from the margin of the iris to those on the front 
part of the capsule of the lens. These vessels have a looped arrangement, con- 
verging toward each other without anastomosing. Between the seventh and eighth 
month the membrane begins to disappear by its gradual absorption from the centre 
toward the circumference, and at birth only a few fragments remain. It is said some- 
times to remain permanent and produce blindness. 
The Ciliary muscle (Bowman) consists of unstriped fibres: it forms a grayish, 
semi-transparent, circular band, about one-eighth of an inch broad, on the outer sur- 
face of the fore part of the choroid. It is thickest in front and gradually becomes 
thinner behind. It consists of two sets of fibres, radiating and circular. The 
former, much the more numerous, arise at the point of junction of the cornea and 
sclerotic, and, passing backward, are attached to the choroid opposite to the ciliary 
processes. The circular fibres are internal to the radiating ones, and to some 
extent unconnected with them, and have a circular course around the insertion of 
the iris. They are sometimes called the "ring muscle" of Muller, and were for- 
merly described as the ciliary ligament. The Ciliary muscle is admitted to be the 
chief agent in accommodation-i. e. in adjusting the eye to the vision of near 
objects. Mr. Bowman believed that 
this was effected by its compressing 
the vitreous body, and so causing the 
lens to advance ; but the view which 
now prevails is that the contraction of 
the muscle by drawing on the ciliary 
processes relaxes the suspensory liga- 
ment of the lens, thus allowing the 
anterior surface of the lens to become 
more convex. The pupil is at the 
same time slightly contracted.1 
The Retina may be exposed by 
carefully removing the choroid from 
its external surface. It is a deli- 
cate nervous membrane, upon the 
surface of which the images of ex- 
ternal objects are received. Its 
outer surface is in contact with the 
choroid, its inner surface with the 
vitreous body. Behind it is con- 
tinuous with the optic nerve; it 
gradually diminishes in thickness from behind forward, and in front extends nearly 
Fig. 534. 
Sclerotic 
-Choroid 
Retina, 
The Arteria Centralis Retinae, Yellow Spot, etc., the anterior 
half of the eyeball being removed (enlarged). 
1 See explanation and diagram in Power's Illustrations of Some of the Principal Diseases of the Eye, 
p. 590. THE EYE. 
813 
as far forward as the ciliary ligament, where it terminates by a jagged margin, the 
ora serrata. It is soft and semi-transparent in the fresh state, but soon becomes 
clouded, opaque, and of a pinkish tint. Exactly in the centre of the posterior part 
of the retina, and at a point corresponding to the axis of the eye, in which the sense 
of vision is most perfect, is a round, elevated, yellowish spot, called, after its discov- 
erer, the yellow spot or limbus luteus (macula lutea) of Sbmmerring, having a cen- 
tral depression at its summit, the/uvea centralis. The retina in the situation of the 
fovea centralis is exceedingly thin; so much so that the dark color of the choroid is 
distinctly seen through it, so that it presents more the appearance of a foramen, and 
hence the name "foramen of Sommerring " at first given to it. It exists only in 
man, the Quadrumana, and some saurian reptiles. About one-tenth of an inch to 
the inner side of the yellow spot is the point of entrance of the optic nerve, the 
arteria centralis retinae piercing its centre. This is the only part of the surface of 
the retina from which the power of vision is absent. 
Structure.-The retina is an exceedingly complex structure, and when examined 
microscopically by means of sections made perpendicularly to its surface is found to 
consist of ten layers, which are named from within outward, as follows: 
1. Membrana limitans interna. 
2. Fibrous layer, consisting of nerve-fibres. 
3. Vesicular layer, consisting of nerve-cells. 
4. Inner molecular or granular layer. 
5. Inner nuclear layer. 
6. Outer molecular or granular layer. 
7. Outer nuclear layer. 
8. Membrana limitans externa. 
9. Layer of rods and cones (Jacob's membrane). 
10. Pigmentary layer. 
1. The membrana limitans interna is the most internal layer of the retina, and 
Fig. 535. 
Fig. 536. 
Vertical Sections of the Human Retina (Fig. 535, half an inch from the entrance of the optic nerve; Fig. 536, 
close to the latter): 1, layer of rods and cones (columnar layer), bounded underneath by the membrana limi- 
tans externa; 2, external nuclear layer; 3, outer molecular layer; 4, internal nuclear layer; 5, inner molecu- 
lar layer; 6, layer of the ganglion-cells; 7, expansion of optic fibres; 8, sustentacular fibres of Muller; 9, 
their attachment to the membrana limitans interna. 
is in contact with the hyaloid membrane of the vitreous humor. It is derived from 
the supporting framework of the retina, with which tissue it will be described. 814 
ORGANS OF SENSE. 
2. The fibrous layer is made up of nerve-fibres, the direct continuation of the 
fibres of the optic nerve. This nerve therefore passes through all the other layers 
of the retina, except the one previously mentioned, to reach its destination in the 
fibrous layer. As the nerve passes through the lamina cribrosa of the sclerotic coat, 
the fibres of which it is composed lay aside their medullary sheaths, and are con- 
tinued onward through the choroid and retina as simple axis-cylinders. When these 
non-medullated fibres reach the internal surface of the retina, they radiate from their 
point of entrance over the surface of the retina, grouped in bundles, and in many 
places, according to Michel, arranged in plexuses. The layer is thickest at the optic 
nerve entrance, and gradually diminishes in thickness toward the ora serrata. 
3. The vesicular layer consists of a single layer of large ganglion-cells, except 
in the macula lutea, where there are several layers. The cells are somewhat flask- 
shaped, their rounded internal margin resting on the preceding layei' and sending 
off a single process, which is prolonged into the fibrous layer and is believed to be 
continuous with a nerve-fibre. From the opposite extremity of the cell one or more 
thicker processes extend into the inner molecular layer, where they divide dichotom- 
ously and become lost in its reticulum, or, according to some, pass through this layer 
to reach the inner nuclear layer. 
4. The inner molecular layer consists of a stratum of glandular-looking sub- 
stance, from which circumstance it is sometimes called the "inner granular" layer. 
It is made up of a dense reticulum of minute fibrils, intermingled with the fine pro- 
cesses of the ganglion-cells and also processes derived from certain cells contained in 
the next layer, immediately to be described. No direct connection between these 
sets of processes has yet been demonstrated, but it is considered probable that they 
do communicate, and that there is therefore a direct connection between the gan- 
glion-cells of the vesicular layer and the nuclear cells of the inner nuclear layer. 
Within the recticulum formed by these fibrils minute clear granules of unknown 
nature are imbedded. 
5. The inner nuclear layer is made up of nuclear bodies, of which there are three 
different kinds: (1) A large number of oval nuclei, which are commonly regarded 
as bipolar nerve-cells, and are much more numerous than either of the other kind. 
They consist of a large oval nuclear body placed vertically to the surface, contain- 
ing a distinct nucleolus: they are surrounded by a small amount of protoplasm, 
which is prolonged into two processes; one of these passes inward into the inner 
molecular layer, is varicose in appearance, and, as stated above, is believed to be 
continuous with the processes of the ganglion-cells; the other process passes out- 
ward into the outer molecular layer, and there bifurcates. According to some 
observers, the divisions thus formed communicate with the rod- and cone-fibres 
(Merkel). (2) At the innermost part of this inner nuclear layer is a stratum of 
cells which are not branched. (3) Some few cells are also found in this layer con- 
nected with the fibres of Muller, and will be described with those structures. 
6. The outer molecular layer is much thinner than the inner molecular layer, 
but, like it, consists of a dense network of minute fibrils and presents the same 
granular appearance. It differs, however, from the inner molecular layer in con- 
taining branched stellate cells, the processes of which are extremely fine and 
exhibit varicosities like nerve-fibrils. They are therefore considered by Schultze 
to be ganglion-cells. 
7. The Outer Nuclear Layer.-Like the inner nuclear layer, this layer contains 
several strata of clear oval nuclear bodies; they are of two kinds, and on account 
of their being respectively connected with the rods and cones of Jacob's membrane 
are named rod-granules and cone-granules. The rod-granules are much the more 
numerous and are placed at different levels throughout the layer. They present a 
peculiar cross-striped appearance, and have prolonged from either extremity a fine 
process: the outermost is continuous with a single rod of Jacob's membrane; the 
innermost passes inward toward the outer molecular layer and terminates in an 
enlarged extremity, from which are given off a number of minute fibrils, which 
enter the outer molecular layer. In its course it presents numerous varicosities. THE EYE. 
815 
The ccne-gramdes, fewer in number than the rod-granules, are placed close to the 
membrana limitans externa and are closely connected with the cones of Jacob's 
membrane. They do not present any cross-striping, but contain a pyriform nucleus 
which almost completely fills the cell. From their inner extremity a thick process 
passes inward to the outer molecular layer, where, like the processes of the rod-cells, 
it terminates in an enlargement from which are given off numerous fine fibrils, which 
enter the outer molecular layer. 
8. The Membrana Limitans Externa.-This layer, like the membrana limitans 
interna, is derived from the fibres of Muller, with which structures it will be 
described. 
9. Jacob's Membrane {Bacillary Layer).-The elements which compose this 
layer are of two kinds, rods and cones, the former being much more numerous than 
the latter. The rods are solid, of nearly uniform size, and arranged perpendicularly 
to the surface. Each rod consists of two an outer and inner, which are 
joined together by a cement-substance and are of about equal length. They differ 
from each other as regards refraction and in their behavior with coloring reagents, 
the inner portion becoming stained by carmine, iodine, etc., the outer portion 
remaining unstained. The outer portion of each rod is marked by transverse striae, 
and is made up of a number of thin disks su- 
perimposed on one another. It also exhibits 
faint longitudinal markings. The inner por- 
tion of each rod at its inner extremity, where 
it is joined to the processes of the rod-gran- 
ules, is indistinctly granular; at its outer ex- 
tremity it presents a fine longitudinal stria- 
tion, being composed of fine, bright, highly 
refracting fibrils. 
The cones are conical or flask-shaped, their 
broad ends resting upon the membrana limi- 
tans externa, the narrow pointed extremity 
being turned to the choroid. Like the rods, 
they are made up of two portions, outer and 
inner, the outer portion being a short conical 
process which, like the outer segment of the 
rods, presents transverse striae. The inner 
portion resembles the inner portion of the rods 
in structure, presenting an outer striated and 
an inner granular appearance, but differs from 
it in size, being bulged out laterally and pre- 
senting a flask shape. 
10. The Pigmentary Layer or Tapetum 
Nigrum.-The most external layer of the 
retina, formerly regarded as a part of the 
choroid, consists of a single layer of hexag- 
onal epithelium cells loaded with pigment- 
granules (Fig. 21, p. 50). In the eyes of 
albinos the cells of the pigmentary layer are 
present, but they contain no coloring mat- 
ter. In many of the mammals also, as in the 
horse and many of the Carnivora, there is no 
pigment in the cells of this layer, and the 
choroid possesses a beautiful iridescent lustre, 
which is termed the tapetum lucidum. 
Connective-tissue Framework of the Retina. 
-Almost all these layers of the retina are 
connected together by a sort of supporting connective tissue, which has been named 
the fibres of Muller or radiating fibres, from which the membrana limitans interna 
Fig. 537. 
The Layers of the Retina (diagrammatic, after 
Schultze): a, membrana limitans interna; &, 
fibrous layer; c, vesicular layer; d, inner mo- 
lecular layer; e, inner nuclear layer; /.outer 
molecular layer; g, outer nuclear layer; h, 
membrana limitans externa; i, Jacob's mem- 
brane ; k, pigmentary layer; I, fibre of Muller. 816 
ORGANS OF SENSE. 
et externa are derived. These fibres are found stretched between the two limiting 
layers " as columns between a floor and a ceiling " and passing through all the ner- 
vous layers, except Jacob's membrane. They commence on the inner surface of the 
retina by a conical base, the edges of the bases of adjoining fibres being united, 
and thus forming a boundary-line, which is the membrana limitans interna. As 
they pass through the various layers they present a roughness of their surface, as 
if from a number of membranous processes abruptly broken off. By these they are 
continuous with the reticulum of the inner and outer molecular layer and with a 
sponge-like stroma in which the nuclei of the inner nuclear layers are imbedded. 
In the inner nuclear layer each fibre of Muller presents a clear oval nucleus, referred 
to above, which is sometimes situated at the side of, sometimes altogether within, the 
fibre. In the outer nuclear layer the fibre breaks up into fine lamellae, which form 
a fenestrated or sponge-like tissue, in -which the rod- and cone-granules are enclosed, 
and at the outer border of this layer these lamellae unite along a definite line, form- 
ing the membrana limitans externa. 
Macula Lutea and Fovea Centralis.-The structure of the retina at the yellow 
spot presents some modifications. In the macula lutea (1) the nerve-fibres are 
wanting as a continuous layer; (2) the vesicular layer consists of several strata of 
cells, instead of a single layer; (3) in Jacob's membrane there are no rods, but 
only cones, and these are longer and narrower than in other parts; and (4) in the 
outer nuclear layer there are only cone-fibres, wThich are very long and arranged in 
curved lines. At the fovea centralis the only parts which exist are the cones of 
Jacob's membrane; the outer nuclear layer, the cone-fibres of which are almost 
horizontal in direction; and an exceedingly thin inner granular layer. The color 
of the spot seems to imbue all the layers except Jacob's membrane; it is of a rich 
yellow, deepest toward the centre, and does not appear to consist of pigment-cells, 
but simply a staining of the constituent parts. 
At the ora serrata the layers of the retina for the most part terminate abruptly, 
and the radiating fibres of Muller, covered by the pigmentary layer, can be traced 
forward, as the pars ciliaris, to the iris. The fibres of Muller here present the 
appearance of columnar epithelial cells arranged in a single stratum. 
The arteria centralis retince with its accompanying vein pierces the optic nerve 
and enters the globe of the eye through the porus opticus. It immediately divides 
into four or five branches, which at first run between the hyaloid membrane and 
the nervous layer; but they soon enter the latter membrane and pass forward, divid- 
ing dichotomously. From these branches a minute capillary plexus is given off 
which does not extend beyond the inner nuclear layer. 
Humors of the Eye 
The Aqueous Humor completely fills the anterior and.posterior chambers of 
the eyeball. It is small in quantity (scarcely exceeding, according to Petit, four 
or five grains in weight), has an alkaline reaction, in composition is little more than 
water, less than one-fiftieth of its weight being solid matter, chiefly chloride of 
sodium. 
The anterior chamber is the space bounded in front by the cornea, behind by 
the front of the iris. The posterior chamber was the name formerly given to a space 
which was believed to exist between the iris in front and the capsule of the lens, its 
suspensory ligament, and the ciliary processes behind. It is now known that the 
posterior surface of the iris is in immediate contact with the lens throughout the 
greater part of its extent. The only space which remains to represent the posterior 
chamber is a narrow chink between the peripheral part of the iris, the suspensory 
ligament, and the ciliary processes. 
In the adult these two chambers communicate through the pupil; but in the 
foetus in the seventh month, when the pupil is closed by the membrana pupillaris, 
the two chambers are quite separate. THE EYE. 
817 
Vitreous Body. 
The Vitreous Body forms about four-fifths of the entire globe. It fills the con- 
cavity of the retina, and is hollowed in front for the reception of the lens and its 
capsule. It is perfectly transparent, of the consistence of thin jelly, and consists 
of an albuminous fluid enclosed in a delicate transparent membrane, the hyaloid. 
This membrane invests the outer surface of the vitreous body; it is intimately con- 
nected in front with the suspensory ligament of the lens, and is continued into the 
back part of the capsule of the lens. It has been supposed by Hannover that from 
its inner surface numerous thin lamellae are prolonged inward in a radiating manner, 
forming spaces in which the fluid is contained. In the adult these lamellae cannot 
be detected even after careful microscopic examination, but in the foetus a peculiar 
fibrous texture pervades the mass, the fibres joining at numerous points and pre- 
senting minute nuclear granules at their point of junction. In the centre of the 
vitreous humor, running from the position of the entrance of the optic nerve on the 
retina to the posterior surface of the lens, is a canal filled with fluid and lined by a 
prolongation of the hyaloid membrane. This is the canal of Stilling. It must not 
be confounded with the canal in the embryonic vitreous humor which conveys the 
minute artery from the central artery of the retina to the back of the lens. The 
fluid from the vitreous body resembles nearly pure water; it contains, however, some 
salts and a little albumen. 
The hyaloid membrane encloses the whole of the vitreous humor except its ante- 
rior surface, which is hollowed out for the reception of the lens; it passes from the 
margin of this surface to the margin of the lens, forming the suspensory ligament. 
It is a delicate structureless membrane, except where it forms the suspensory liga- 
ment, where it contains longitudinal elastic fibres. Immediately beneath the hyaloid 
membrane are found small, granular nucleated cells which are said to be possessed 
of amoeboid movements. 
In the foetus the centre of the vitreous humor presents a tubular canal, through 
which a minute artery passes along the vitreous body to the capsule of the lens. In 
the adult no vessels penetrate its substance, so that its nutrition must be carried on 
by the vessels of the retina and ciliary processes situated upon its exterior. 
Crystalline Lens and its Capsule. 
[Dissection.-After dissecting away the anterior half of the sclerotic and the cornea of the 
bullock's eye, as directed on p. 808, the canal of Petit can be opened by a hook and a slender 
bent probe inserted into it. If the capsule on the anterior surface of the lens be torn across 
by a hook or divided by a knife, and the lens be gently pressed out, the edge of the capsule can 
be seized by a pair of forceps.] 
The crystalline lens, enclosed in its capsule, is situated immediately behind the 
pupil, in front of the vitreous body, and surrounded by the ciliary processes, which 
slightly overlap its margin. 
The capsule of the lens is a transparent, highly elastic, and brittle membrane 
which closely surrounds the lens. It rests behind in a depression in the fore part 
of the vitreous body ; in front it is in contact with the free border of the iris [hence 
the ease with which adhesions form in iritis], this latter receding from it at the cir- 
cumference, thus forming the posterior chamber of the eye; and it is retained in its 
position chiefly by the suspensory ligament of the lens. The capsule is much thicker 
in front than behind, structureless in texture, and when ruptured the edges roll up 
with the outer surface innermost, like the elastic lamina of the cornea. The ante- 
rior surface of the lens is connected to the inner surface of the capsule by a single 
layer of transparent, polygonal, nucleated cells. At the circumference of the lens 
these cells undergo a change in form : they become elongated, and Babucin states 
that he can trace the gradual transition of the cells into proper lens-fibres, with 
which they are directly continuous. There is no epithelium on the posterior surface. 
In the foetus a small branch from the arteria centralis retinae runs forward, as 818 
ORGANS OF SENSE. 
already mentioned, through the vitreous humor to the posterior part of the capsule 
of the lens, where its branches radiate and form a plexiform network which covers 
its surface, and they are continuous round the margin of the capsule with the vessels 
of the pupillary membrane and with those of the iris. In the adult no vessels enter 
its substance. 
The lens is a transparent double-convex body, the convexity being greater on 
the posterior than on the anterior surface. It measures about a third of an inch 
in the transverse diameter and about one-fourth in the an- 
tero-posterior. It consists of concentric layers, of which the 
external in the fresh state are soft and easily detached; those 
beneath are firmer, the central ones forming a hardened nu- 
cleus. These laminae are best demonstrated by boiling or 
immersion in alcohol. The same reagents demonstrate that 
the lens consists of three triangular segments, the sharp 
edges of which are directed toward the centre, the bases 
toward the circumference. The laminae consist of minute 
parallel fibres which are hexagonal prisms, the edges be- 
ing dentated, and the dentations fitting accurately into 
each other; their breadth is about 5 0 of an inch. They 
run from the sutures or lines of junction of the triangular 
segments on the one surface to the periphery of the lens, and, curving round its 
margin, they terminate at the line of junction of the segments on the other. No 
fibres pass from pole to pole, but they are arranged in such a way that fibres which 
commence near the pole on the one aspect of the lens-that is to say, near the apex 
of the triangular segment-terminate near the peripheral extremity of the plane on 
the other; that is to say, near the base of the triangular segment, and vice versd. 
The fibres of the outer layers of the lens each contain a nucleus which together form 
a layer (nuclear layer) on the surface of the lens, most distinct toward its circum- 
ference. The meridians, or lines of junction of the three segments, are composed 
of an amorphous granular substance which sometimes becomes opaque, when the 
lines are seen forming a distinct star on the lens. The lines on one surface do not 
lie immediately opposite those on the other, but are intermediate. 
The changes produced in the lens by age are the following: 
In the foetus its form is nearly spherical, its color of a slightly reddish tint; it is 
not perfectly transparent, and is so soft as to break down readily on the slightest 
pressure. 
In the adult the posterior surface is more convex than the anterior; it is color- 
less, transparent, and firm in texture. 
In old age it becomes flattened on both surfaces, slightly opaque, of an amber 
tint, and increases in density. 
The suspensory ligament of the lens is a thin, transparent, membranous structure 
placed between the vitreous body and the ciliary processes of the choroid; it con- 
nects the anterior margin of the vitreous humor with the anterior surface of the lens 
near its circumference. It assists in retaining the lens in its position. Its outer sur- 
face presents a number of folds or plaitings in which the corresponding folds of the 
ciliary processes are received. These plaitings are arranged round the lens in a radi- 
ating form, and are stained by the pigment of the ciliary processes. It is a part of 
the hyaloid membrane, which, as described above, is continued forward to the ante- 
rior part of the margin of the lens. It is covered on its outer surface by the pars 
ciliaris, or connective-tissue framework of the retina, prolonged forward from the 
ora serrata. That portion of this membrane which intervenes between the ciliary 
processes and the capsule of the lens forms part of the boundary of the posterior 
chamber of the eye. The posterior surface of this layer is turned toward the vitre- 
ous humor, being separated from it at the circumference of the lens by a space called 
the canal of Petit. 
The canal of Petit is about one-tenth of an inch wide. It is bounded in front 
by the suspensory ligament; behind by the vitreous humor, its base being formed 
Fig. 538. 
The Crystalline Lens, hard- 
ened and divided (en- 
larged). THE EYE. 
819 
by the capsule of the lens. When inflated with air it is sacculated at intervals, 
owing to the foldings on its anterior surface. 
The vessels of the globe of the eye are the short, long, and anterior ciliary arteries 
and the arteria centralis retinse. 
The short ciliary arteries pierce the back part of the sclerotic, around the 
entrance of the optic nerve, and divide into branches which run parallel with the 
axis of the eyeball: they are distributed to the inner layer of the choroid and to 
the ciliary processes. 
The long ciliary arteries, two in number, pierce the back part of the sclerotic 
and run forward, between that membrane and the choroid, to the Ciliary muscle, 
where they each divide into an upper and lower branch; these anastomose and 
form a vascular circle round the outer circumference of the iris; from this circle 
branches are given off, which unite near the margin of the pupil in a smallei' vas- 
cular circle. These branches in their course supply the muscular structure. 
The anterior ciliary arteries, five or six in number, are branches of the muscu- 
lar and lachrymal branches of the ophthalmic. They pierce the eyeball at the 
anterior part of the sclerotic, immediately behind the margin of the cornea, and 
are distributed to the ciliary processes, some branches joining the great vascular 
circle of the iris. 
The arteria centralis retince has been already described. 
The veins, usually four in number, are formed mainly by branches from the sur- 
face of the choroid. They perforate the sclerotic midway between the cornea and 
the optic nerve and end in the ophthalmic vein. 
The nerves of the eyeball are the optic, the long ciliary nerves from the nasal 
branch of the ophthalmic, and the short ciliary nerves from the ciliary ganglion. 
Appendages of the Eye. 
The appendages of the eye (tutamina oculi) include the eyebrows, the eyelids, 
the conjunctiva, and the lachrymal apparatus-viz. the lachrymal gland, the lach- 
rymal sac, and the nasal duct. 
The Eyebrows [supercilid) are two arched eminences of integument which sur- 
mount the upper circumference of the orbit on each side and support numerous short, 
thick hairs directed obliquely on the surface. In structure the eyebrows consist of 
thickened integument connected beneath with the Orbicularis palpebrarum, Corruga- 
tor supercilii, and Occipito-frontalis muscles. These muscles serve by their action on 
this part to control to a certain extent the amount of light admitted into the eye. 
The Eyelids [palpebrce) are two thin, movable folds placed in front of the eye, 
protecting it from injury by their closure. The upper lid is the larger and the more 
movable of the two, and is furnished with a separate elevator muscle, the Levator 
palpebrce superioris. When the eyelids are opened an elliptical space [fissura pal- 
pebrarum) is left between their margins, the angles of which correspond to the 
junction of the upper and lower lids, and are called canthi. 
The outer canthus is more acute than the inner, and the lids here lie in close 
contact with the globe; but the inner canthus is prolonged for a short distance 
inward toward the nose, and the two lids are separated by a triangular space, the 
lacus lachrymalis. At the commencement of the lacus lachrymalis, on the margin 
of either eyelid, is a small conical elevation, the lachrymal papilla, or tubercle, the 
apex of which is pierced by a small orifice, the punctum lachryniale, the commence- 
ment of the lachrymal canal. 
Structure of the Eyelids.-The eyelids are composed of the following struc- 
tures, taken in their order from without inward: 
Integument, areolar tissue, fibres of the Orbicularis muscle, tarsal cartilage and 
its ligament, Meibomian glands, and conjunctiva. The upper lid has,, in addition, 
the aponeurosis of the Levator palpebrse. 
The integument is extremely thin, and continuous at the margin of the lids with 
the conjunctiva. 820 
ORGANS OF SENSE. 
The subcutaneous areolar tissue is very lax and delicate, seldom contains any fat, 
and is extremely liable to serous infiltration. 
The fibres of the Orbicularis muscle, where they cover the palpebrae, are thin, 
pale in color, and possess an involuntary action. 
The tarsal cartilages are two thin elongated plates of dense connective tissue,1 
about an inch in length. They are placed one in each lid, contributing to their 
form and support. 
The superior, the larger, is of a semilunar form, about one-third of an inch in 
breadth at the centre, and becoming gradually narrowed at each extremity. Into 
the anterior surface of this cartilage the aponeurosis of the Levator palpebrse is 
attached. 
The inferior tarsal cartilage, the smaller, is thinner and of an elliptical form. 
The free or ciliary margin of the cartilages is thick and presents a perfectly 
straight edge. The attached or orbital margin is connected to the circumference of 
the orbit by the fibrous membrane of the lids. The outer angle of each cartilage is 
attached to the malar bone by the external palpebral or tarsal ligament. The inner 
angles of the two cartilages terminate at the commencement of the lacus lachrymalis, 
being fixed to the margins of tlue orbit by the tendo oculi. 
The tarsal ligament or fibrous membrane of the lids is a layer of fibrous mem- 
brane beneath the Orbicularis, attached externally to the margin of the orbit, and 
internally it passes over the anterior surface of the tarsal cartilage and is attached 
to its free margin. It is thickest and densest at the outer part of the orbit. This 
membrane serves to support the eyelids and retain the tarsal cartilages in their 
position. 
The Meibomian glands (Fig. 539) are situated upon the inner surface of the 
eyelids, between the tarsal cartilages and conjunctiva, and may be distinctly seen 
through the mucous membrane on everting the eyelids, presenting the appearance 
of parallel strings of pearls. They are about thirty in number in the upper carti- 
lage, and somewhat fewer in the lower. They are imbedded in grooves in the inner 
surface of the cartilages, and 
correspond in length with 
the breadth of each carti- 
lage ; they are consequently 
longer in the upper than in 
the lower eyelid. Their 
ducts open on the free mar- 
gin of the lids by minute 
foramina which correspond 
in number to the follicles. 
These glands are a variety 
of the cutaneous sebaceous 
glands, each consisting of a 
single straight tube or folli- 
cle having a caecal termina- 
tion, into which open a num- 
ber of small secondary folli- 
cles. The tubes consist of 
basement membrane covered 
by a layer of scaly epithe- 
lium ; the secondary follicles are lined by a layer of polyhedral cells continuous 
with the cells of the tube. The remainder of the follicle is filled with large poly- 
hedral cells charged with fat. They are thus identical in structure with the seba- 
ceous glands. The peculiar parallel arrangement of these glands side by side forms 
a smooth layer adapted to the surface of the globe, over which they constantly glide. 
The use of their secretion is to prevent adhesion of the lids. 
Fig. 539. 
•Punefa. 
Ltw/irymal in 
The Meibomian Glands, etc., seen from the inner surface of the eyelids. 
1 Recent observations have proved that the so-called "tarsal cartilages" do not contain any carti- 
lage-cells and that the name is a misnomer. THE EYE. 
821 
The eyelashes (cilia) are attached to the free edges of the eyelids; they are 
short, thick, curved hairs arranged in a double or triple row at the margin of the 
lids: those of the upper lid, more numerous and longer than the lower, curve 
upward; those of the lower lid curve downward, so that they do not interlace in 
closing the lids. 
The Conjunctiva is the mucous membrane of the eye. It lines the inner sur- 
face of the eyelids and is reflected over the fore part of the sclerotic and cornea. 
In each of these situations its structure presents some peculiarities. 
The palpebral portion of the conjunctiva is thick, opaque, highly vascular, and 
covered with numerous papillae, which in the disease called granular lids become 
greatly hypertrophied. At the margin of the lids it becomes continuous with the 
lining membrane of the ducts of the Meibomian glands, and through the lachrymal 
canals with the lining membrane of the lachrymal sac and nasal duct. At the outer 
angle of the upper lid it may be traced along the lachrymal ducts into the lachrymal 
gland, and at the inner angle of the eye it forms a semilunar fold, the plica semilu- 
naris. The folds formed by the reflection of the conjunctiva from the lids on to 
the eye are called the superior and inferior palpebral folds, the former being the 
deeper of the two. Upon the sclerotic the conjunctiva is loosely connected to the 
globe: it becomes thinner, loses its papillary structure, is transparent, and only 
slightly vascular in health. Upon the cornea the conjunctiva consists only of epi- 
thelium, constituting the anterior layer of the cornea (conjunctival. epithelium) 
already described. (See p. 807.) The deeper parts of the palpebral conjunctiva pre- 
sent, according to Henle, a considerable proportion of lymphoid tissue. Lymphatics 
arise in the conjunctiva in a delicate zone around the cornea, from which the vessels 
run to the ocular conjunctiva. 
At the point of reflection of the conjunctiva from the lid on to the globe of the 
eye, termed the fornix conjunctivae, are a number of mucous glands which are much 
convoluted. They are chiefly found in the upper lid. Other glands, analogous to 
lymphoid follicles and called by Henle " trachoma glands f are found in the con- 
junctiva, and, according to Stromeyer, are chiefly situated near the inner canthus 
of the eye. They were first described by Brush, in his description of Peyer's 
patches of the small intestines, as " identical structures existing in the under eyelid 
of the ox." 
The nerves in the conjunctiva are numerous and form rich plexuses. Accord- 
ing to Krause, they terminate in a peculiar form of tactile corpuscle which he terms 
" terminal bulb." 
The caruncula lachrymalis is a small, reddish, conical-shaped body situated at 
the inner canthus of the eye and filling up the small triangular space in this situa- 
tion, the lacus lachrymalis. It consists of a cluster of follicles similar in structure 
to the Meibomian, covered with mucous membrane, and is the source of the whitish 
secretion which constantly collects at the inner angle of the eye. A few slender 
hairs are attached to its surface. On the outer side of the caruncula is a slight 
semilunar fold of mucous membrane, the concavity of which is directed toward the 
cornea; it is called the plica semilunaris. Muller found smooth muscular fibres in 
this fold, and in some of the domestic animals a thin plate of cartilage has been 
discovered. This structure is considered to be the rudiment of the third eyelid in 
birds, the membrana nictitans. 
Lachrymal Apparatus (Fig. 540). 
The lachrymal apparatus consists of the lachrymal gland, which secretes the 
tears, and its excretory ducts, which convey the fluid to the surface of the eye. 
This fluid is carried away by the lachrymal canals into the lachrymal sac and along 
the nasal duct into the cavity of the nose. 
The Lachrymal G-land is lodged in a depression at the outer angle of the orbit, 
on the inner side of the external angular process of the frontal bone. It is of an 
oval form, about the size and shape of an almond. Its upper convex surface is in 822 
ORGANS OF SENSE. 
contact with the periosteum of the orbit, to which it is connected by a few fibrous 
bands. Its under concave surface rests 
upon the convexity of the eyeball and 
upon the Superior and External recti 
muscles. Its vessels and nerves enter its 
posterior border, whilst its anterior mar- 
gin is closely adherent to the back part 
of the upper eyelid, and is covered on its 
inner surface by a reflection of the con- 
junctiva. The fore part of the gland is 
separated from the rest by a fibrous sep- 
tum ; hence it is sometimes described as 
a separate lobe, called the palpebral por- 
tion of the gland (accessory gland of 
Ro senmuller'). In structure and general 
appearance the lachrymal resembles the 
salivary glands (p. 852). The histolog- 
ical characters are those of an albumin- 
ous gland. In the recent state the cells 
are so crowded with granules that their 
limits can hardly be defined. They con- 
tain an oval nucleus and the cell-proto- 
plasm is finely fibrillated. Its ducts, about seven in number, run obliquely beneath 
the mucous membrane for a short distance, and, separating from each other, open by 
a series of minute orifices on the upper and outer half of the conjunctiva, near its 
reflection on to the globe. These orifices are arranged in a row, so as to disperse 
the secretion over the surface of the membrane. 
The Lachrymal Canals commence at the minute orifices, puncta lachrymalia, 
seen on the margin of the lids at the outer extremity of the lacus lachrymalis. 
They commence on the summit of a slightly elevated papilla, the papilla lachry- 
malis, and lead into minute canals, the canaliculi, which proceed inward to termi- 
nate in the lachrymal sac. The superior canal, the smaller and shorter of the two, 
at first ascends, and then bends at an acute angle, and passes inward and downward 
to the lachrymal sac. The inferior canal at first descends, and then, abruptly 
changing its course, passes almost horizontally inward. They are dense and elastic 
in structure and somewhat dilated at their angle. [A fine probe should bp passed 
into them to appreciate their length and direction.] 
The Lachrymal Sac is the upper dilated extremity of the nasal duct, and is 
lodged in a deep groove formed by the lachrymal bone and nasal process of the 
superior maxillary. It is oval in form, its upper extremity being closed in and 
rounded, whilst below it is continued into the nasal duct. It is covered by a 
fibrous expansion derived from the tendo oculi, and on the inner side it is crossed 
by the Tensor tarsi muscle [or muscle of Horner, p. 371], which is attached to the 
ridge on the lachrymal bone. In structure it consists of a fibrous elastic coat lined 
internally by mucous membrane, the latter being continuous through the canaliculi 
with the mucous lining of the conjunctiva, and through the nasal duct with the 
pituitary membrane of the nose. 
The Nasal Duct is a membranous canal about three-quarters of an inch in 
length which extends from the lower part of the lachrymal sac to the inferior 
meatus of the nose, where it terminates by a somewhat expanded orifice, provided 
with an imperfect valve, the valve of Hasner, formed by the mucous membrane. It 
is contained in an osseous canal formed by the superior maxillary, the lachrymal, 
and the inferior turbinated bones, is narrower in the middle than at each extrem- 
ity, and takes a direction downward, backward, and a little outward. It is lined 
by mucous membrane, which is continuous below with the pituitary lining of the 
nose. In the canaliculi this membrane is provided with scaly epithelium, but in 
the lachrymal sac and nasal duct the epithelium is ciliated, as in the nose. 
Fig. 540. 
JPunctcc Laclnymalta < 
The Lachrymal Apparatus, right side. THE EAR. 
823 
THE EAR. 
The organ of hearing is divisible into three parts: the external ear, the middle 
ear or tympanum, and the internal ear or labyrinth. 
The External Ear consists of an expanded portion named pinna or auricle, and 
the auditory canal, or meatus. The former serves to collect the vibrations of the air by 
which sound is produced, and the latter conducts those vibrations to the tympanum. 
The Pinna or Auricle (Fig. 541) is formed by a layer of yellow fibro-cartilage 
covered with integument, and connected to the commencement of the auditory 
canal: it is of an ovoid form, its surface uneven, with 
its larger end directed upward. Its outer surface is 
irregularly concave, directed slightly forward, and pre- 
sents numerous eminences and depressions which result 
from the foldings of its fibro-cartilaginous element. To 
each of these names have been assigned. Thus the 
external prominent rim of the auricle is called the 
helix. Another curved prominence parallel with, and 
in front of, the helix is called the antihelix ; this bifur- 
cates above, so as to enclose a triangular depression, the 
fossa of the antihelix. The narrow curved depression 
between the helix and antihelix is called the fossa of 
the helix (fossa innominata or scaphoidea}; the anti- 
helix describes a curve round a deep, capacious cavity, 
the concha, which is partially divided into tw7o parts 
by the commencement of the helix. In front of the 
concha and projecting backward over the meatus is a 
small pointed eminence, the tragus, so called from its 
being generally covered on its under surface with a tuft 
of hair resembling a goat's beard. Opposite the tragus, 
and separated from it by a deep notch (incisura inter- 
tragicaf is a small tubercle, the antitragus. Below this 
is the lobule, composed of tough areolar and adipose tissue, wanting the firmness and 
elasticity of the rest of the pinna. 
Structure of the Pinna.-The pinna is composed of a thin plate of yellow 
fibro-cartilage covered with integument and connected to the surrounding parts by 
ligaments and a few muscular fibres. 
The integument is thin, closely adherent to the cartilage, and furnished with 
sebaceous glands, which are most numerous in the concha and scaphoid fossa. 
The cartilage of the pinna consists of one single piece; it gives form to this 
part of the ear, and upon its surface are found all the eminences and depressions 
above described. It does not enter into the construction of all parts of the auricle; 
thus it does not form a constituent part of the lobule; it is deficient also between 
the tragus and beginning of the helix, the notch between them being filled up by 
dense fibrous tissue. At the front part of the pinna, where the helix bends upward, 
is a small projection of cartilage called the process of the helix. The cartilage of 
the pinna presents several intervals or fissures in its substance which partially sepa- 
rate the different parts. The fissure of the helix is a short vertical slit situated at 
the fore part of the pinna, immediately behind a small conical projection of carti- 
lage, opposite the first curve of the helix (process of the helix). Another fissure, 
the fissure of the tragus, is seen upon the anterior surface of the tragus. The anti- 
helix is divided below by a deep fissure into two parts: one part terminates by a 
pointed, tail-like extremity (processus caudatus}; the other is continuous with the 
antitragus. The cartilage of the pinna is very pliable, elastic, of a yellowish color, 
and belongs to that form of cartilage which is known under the name of yellow 
fibro-cartilage. 
The ligaments of the pinna consist of two sets : 1, those connecting it to the side 
of the head; 2, those connecting the various parts of its cartilage together. 
Fig. 541. 
The Pinna, or Auricle, outer sur- 
face. 824 
ORGANS OF SENSE. 
The former, the most important, are two in number, anterior and posterior. The 
anterior ligament extends from the process of the helix to the root of the zygoma. 
The posterior ligament passes from the posterior surface of the concha to the outer 
surface of the mastoid process of the temporal bone. A few fibres connect the 
tragus to the root of the zygoma. 
The ligaments connecting the various parts of the cartilage together are also two 
in number. Of these, one is a strong fibrous band stretching across from the tragus 
to the commencement of the helix, completing the meatus in front and partly encir- 
cling the boundary of the concha; the other extends between the concha and the 
processus caudatus. 
The muscles of the pinna (Fig. 542), like the ligaments, consist of two sets: 1, 
those which connect it with the side of the head, moving the pinna as a whole-viz. 
the Attollens, Attrahens, and Retrahens aurem (p. 369); and 2, the proper muscles 
of the pinna, which extend from one part of the auricle to another. These are the 
Helicis major. 
Helicis minor. 
Tragicus. 
Antitragicus. 
Transversus auriculae. 
Obliquus auris. 
The M. Helicis major is a narrow vertical band of muscular fibres situated upon 
the anterior margin of the helix. It arises below from the process of the helix, and 
is inserted into the anterior border 
of the helix just where it is about to 
curve backward. It is pretty con- 
stant in its existence. 
The fl/. Helicis minor is an ob- 
lique fasciculus attached to that part 
of the helix which commences from 
the bottom of the concha. 
The Tragicus is a short, flattened 
band of muscular fibres situated upon 
the outer surface of the tragus, the 
direction of its fibres being vertical. 
The Antitragicus arises from the 
outer part of the antitragus: its fibres 
are inserted into the processus cauda- 
tus of the helix. This muscle is usu- 
ally very distinct. 
The Transversus auriculce is placed 
on the cranial surface of the pinna. 
It consists of radiating fibres, partly 
tendinous and partly muscular, ex- 
tending from the convexity of the 
concha to the prominence correspond- 
ing with the groove of the helix. 
The Obliquus auris (Todd) con- 
sists of a few fibres extending from 
the upper and back part of the concha 
to the convexity immediately above it. 
The arteries of the pinna are the posterior auricular, from the external carotid; 
the anterior auricular, from the temporal; and an auricular branch, from the occipi- 
tal artery. 
The veins accompany the corresponding arteries. 
The nerves are the auricularis magnus, from the cervical plexus; the posterior 
auricular, from the facial; the auricular branch of the pneumogastric; the auriculo- 
temporal branch of the inferior maxillary nerve; the occipitalis minor, from the cer- 
vical plexus; and the occipitalis major or internal branch of the posterior division 
of the second cervical nerve. 
Fig. 542. 
The Muscles of the Pinna. THE EAR. 
825 
[The student who will take a little trouble in noticing the ears of the persons 
whom he meets from day to day will be greatly interested and surprised to see how 
much the auricle varies. It may be a thick and clumsy ear or a beautifully delicate 
one; long and narrow or short and broad; may have a neatly-formed and distinct 
lobule, or one that is heavy, ungainly, and united to the cheek so as hardly to form 
a separate part of the auricle; may hug the head closely or flare outward so as to 
form almost two wings to the head. In art, and especially in medallion portraits, in 
which the ear is a marked (because central) feature, the auricle is of great import- 
ance. The little muscles of the auricle, though so rudimentary, can be readily 
called into action by the battery.] 
The Auditory Canal (meatus auditorius externus} (Fig. 543) extends from the 
bottom of the concha to the membrana tympani. It is about an inch and a quarter 
in length, its direction is obliquely forward and inward, and it is slightly curved 
upon itself, so as to be 
higher in the middle than 
at either extremity. It 
forms an oval cylindrical 
canal, the greatest diameter 
being in the vertical direc- 
tion at the external orifice, 
but in the transverse direc- 
tion at the tympanic end. 
The calibre of the canal is 
narrowest about the middle. 
The membrana tympani, 
which occupies the termi- 
nation of the meatus, is 
obliquely directed, in con- 
sequence of which the floor 
of the canal is longer than 
the roof, and the anterior 
wall longer than the poste- 
rior. The auditory canal is 
formed partly by cartilage and membrane and partly by bone. 
The cartilaginous portion is about half an inch in length, being rather less than 
half the canal; it is formed by the cartilage of the concha and tragus, prolonged 
inward and firmly attached to the circumference of the auditory process. The 
cartilage is deficient at its upper and back part, its place being supplied by fibrous 
membrane. This part of the canal is rendered extremely movable by two or three 
deep fissures (incisures Santorini} which extend through the cartilage in a vertical 
direction. 
The osseous portion is about three-quarters of an inch in length, and narrower 
than the cartilaginous portion. It is directed inward and a little forward, forming 
a slight curve in its course, the convexity of which is upward and backward. Its 
inner end, which communicates in the dry bone with the cavity of the tympanum, 
is smaller than the outer, and sloped, the anterior wall projecting beyond the poste- 
rior about two lines; it is marked, except at its upper part, by a narrow groove for 
the insertion of the membrana tympani. Its outer end is dilated and rough, in the 
greater part of its circumference, for the attachment of the cartilage of the pinna. 
Its vertical transverse section is oval, the greatest diameter being from above down- 
ward. The front and lower parts of this canal are formed by a curved plate of 
bone, which in the foetus exists as a separate ring (tympanic bone) incomplete at its 
upper part. 
The skin lining the meatus is very thin, adheres closely to the cartilaginous and 
osseous portion of the tube, and covers the surface of the membrana tympani, form- 
ing its outer layer. After maceration the thin pouch of epidermis, when withdrawn, 
preserves the form of the meatus. The skin near its orifice is furnished with hairs 
Fig. 543. 
Incu.. 
ptapes 
1 (.mi.-GiroLb I ar Ca/nals 
sCochlui 
'yii'inbra/na. \ 
t«*vr.«y of 
Ty mjKiinu.in' 
A Front View of the Organ of Hearing, right side. 826 
ORGANS OF SENSE. 
and sebaceous glands. In the thick subcutaneous tissue of the cartilaginous part of 
the meatus are numerous ceruminous glands which secrete the ear-wax : their ducts 
open on the surface of the skin. 
The arteries supplying the meatus are branches from the posterior auricular, 
internal maxillary, and temporal. 
The nerves are chiefly derived from the auriculo-temporal branch of the inferior 
maxillary nerve. 
Middle Ear, or Tympanum. 
The Middle Ear, or Tympanum [ru/zTravou, a drum], is an irregular cavity 
compressed from without inward, and situated within the petrous bone. It is placed 
above the jugular fossa, the carotid canal lying in front, the mastoid cells behind, 
the meatus auditorius externally, and the labyrinth internally. It is filled with air, 
and communicates with the pharynx by the Eustachian tube. The tympanum is 
traversed by a chain of movable bones, which connect the membrana tympani with 
the labyrinth, and serve to convey the vibrations communicated to the membrana 
tympani across the cavity of the tympanum to the internal ear. 
The cavity of the tympanum measures about five lines from before backward, 
three lines in the vertical direction, and between two and three in the transverse, 
being a little broader behind and above than it is below and in front. It is bounded 
externally by the membrana tympani and meatus; internally by the outer surface 
of the internal ear; and communicates behind with the mastoid cells, and in front 
with the Eustachian tube and canal for the Tensor tympani. Its roof and floor are 
formed by thin osseous laminae, the one forming the roof being a thin plate situated 
on the anterior surface of the petrous bone close to its angle of junction with the 
squamous portion of the temporal bone. 
The roof is broad, flattened, and formed of a thin plate of bone, which separates 
the cranial and tympanic cavities. 
The floor is narrow and corresponds to the jugular fossa, which lies beneath. 
It presents near the inner wall a small aperture for the passage of Jacobson's nerve. 
The outer wall is formed mainly by the membrana tympani, partly by the ring 
of bone into which this membrane is inserted. It presents three small apertures- 
the iter chordae posterius, the Glaserian fissure, and the iter chordae anterius. 
The aperture of the iter chordce posterius is in the angle of junction between 
the posterior and external walls of the tympanum, immediately behind the mem- 
brana tympani and on a level with its centre; it leads into a minute canal which 
descends in front of the aquaeductus Fallopii and terminates in that canal near 
the stylo-mastoid foramen. Through it the chorda tympani nerve enters the 
tympanum. 
The Glaserian fissure opens just above and. in front of the ring of bone into 
which the membrana tympani is inserted; in this situation it is a mere slit about 
a line in length. It lodges the long process of the malleus and gives passage to 
some tympanic vessels. 
The aperture of the iter chordce anterius is seen just above the preceding fissure; 
it leads into a canal (canal of Huguier) which runs parallel with the Glaserian fis- 
sure. Through it the chorda tympani nerve leaves the tympanum. 
The internal wall of the tympanum (Fig. 544) is vertical in direction and looks 
directly outward. It presents for examination the following parts: 
Fenestra ovalis. 
Fenestra rotunda. 
Promontory. 
Ridge of the aquseductus Fallopii. 
Pyramid. 
Opening for the Stapedius. 
The fenestra ovalis is a reniform opening leading from the tympanum into the 
vestibule; its long diameter is directed horizontally, and its convex border is upward. 
The opening in the recent state is occupied by the base of the stapes, which is con- 
nected to the margin of the foramen by an annular ligament. THE EAR. 
827 
The fenestra rotunda is an aperture placed at the bottom of a funnel-shaped 
depression leading into the cochlea. It is situated below and rather behind the 
fenestra ovalis, from which it is separated by a rounded elevation, the promontory; 
it is closed in the recent state by a membrane (membrana tympani secundaria, 
Scarpa). This membrane is concave toward the tympanum, convex toward the 
Fig. 544. 
Chorda Tympani 
View of Inner Wall of Tympanum (enlarged). 
cochlea. It consists of three layers: the external, or mucous, derived from the 
mucous lining of the tympanum; the internal, or serous, from the lining membrane 
of the cochlea; and an intermediate or fibrous layer. 
The promontory is a rounded hollow prominence formed by the projection out- 
ward of the first turn of the cochlea; it is placed between the fenestras, and is 
furrowed on its surface by three small grooves which lodge branches of the tym- 
panic plexus. 
The rounded eminence of the aquceductus Fallopii, the prominence of the bony 
canal in which the portio dura [facial nerve] is contained, traverses the inner wall 
of the tympanum above the fenestra ovalis, and behind that opening curves nearly 
vertically downward along the posterior wall. 
The pyramid is a conical eminence situated immediately behind the fenestra 
ovalis and in front of the vertical portion of the eminence above described; it is 
hollow in the interior, and contains the Stapedius muscle; its summit projects for- 
ward toward the fenestra ovalis, and presents a small aperture which transmits the 
tendon of the muscle. The cavity in the pyramid is prolonged into a minute canal 
which communicates with the aquseductus Fallopii and transmits the nerve which 
supplies the Stapedius. 
The posterior wall of the tympanum is wider above than below, and presents 
for examination the 
Openings of the mastoid cells [Fig. 143, p. 172]. 
These consist of one large irregular aperture and several smaller openings situ- 
ated at the upper part of the posterior wall; they lead into canals which communi- 
cate with large irregular cavities contained in the interior of the mastoid process. 
These cavities vary considerably in number, size, and form; they are lined by 
mucous membrane continuous with that covering the cavity of the tympanum. [The 
ease with which an inflammation of the middle ear may extend into the mastoid 
cells and produce "mastoid disease," and even lead to thrombosis of the lateral 
sinus and to abscesses of the brain, is now readily appreciated.] 
The anterior wall of the tympanum is wider above than below; it corre- 
sponds with the carotid canal, from which it is separated by a thin plate of bone 828 
ORGANS OF SENSE. 
perforated by the tympanic branch of the internal carotid. It presents for exam- 
ination the 
Canal for the Tensor tympani. 
The processus cochleariformis. 
Orifices of the Eustachian tube. 
The orifice of the canal for the Tensor tympani and the orifice of the Eustachian 
tube are situated at the upper part of the anterior wall, being separated from each 
other by a thin, delicate, horizontal plate of bone, the processus cochleariformis. 
These canals run from the tympanum forward, inward, and a little downward to the 
retiring angle between the squamous and petrous portions of the temporal bone. 
The canal for the Tensor tympani is the superior and the smaller of the two; it 
is rounded, and lies beneath the upper surface of the petrous bone close to the 
hiatus Fallopii. The tympanic end of this canal forms a conical eminence which is 
prolonged backward into the cavity of the tympanum, and is perforated at its sum- 
mit by an aperture which transmits the tendon of the muscle contained in it. This 
eminence is sometimes called the anterior pyramid. The canal contains the Tensor 
tympani muscle. 
The Eustachian tube is the channel through which the tympanum communicates 
with the pharynx. Its length is from an inch and a half to two inches, and its 
[Fig. 545. 
Vertical Section of the Right Eustachian Tube, Tympanic Cavity, and Mastoid Cells, with inner surface of the 
squama above, viewed from within: a, membrana tympani; b, head of malleus; c, end of the manubrium 
mallei; d, incus; e, short process of incus; /, Tensor tympani muscle; g, faucial opening of the Eustachian 
tube; h, isthmus tubse; i, tympanic mouth of Eustachian tube.] 
direction downward, forward, and inward. It is formed partly of bone, partly of 
cartilage and fibrous tissue. 
The osseous portion is about half an inch in length. It commences in the lower 
part of the anterior wall of the tympanum, below the processus cochleariformis, and, 
gradually narrowing, terminates in an oval dilated opening at the angle of junction THE EAR. 
829 
of the petrous and squamous portions, its extremity presenting a jagged margin 
■which serves for the attachment of the cartilaginous portion. 
The cartilaginous portion, about an inch in length, is formed of a triangular 
plate of elastic fibro-cartilage curled upon itself, an interval being left below 
between the margins of the cartilage, which is completed by fibrous tissue. Its 
canal is narrow behind, wide, expanded, and somewhat trumpet-shaped in front, 
terminating by an oval orifice at the upper part and side of the pharynx, behind 
the back part of the inferior meatus [Fig. 184, p. 218]. Through this canal the 
mucous membrane of the pharynx is continuous with that which lines the tympa- 
num. The mucous membrane is covered with ciliated epithelium. 
The Membrana tympani separates the cavity of the tympanum from the bottom 
of the external meatus. It is a thin, semi-transparent membrane, nearly oval in 
form, somewhat broader above than below, and directed very obliquely downward 
and inward. Its circumference is contained in a groove at the inner end of the 
meatus, which skirts the circumference of this part, excepting above. The handle 
of the malleus descends vertically between the inner and middle layers of this mem- 
brane as far down as its centre, where it is firmly attached, drawing the membrane 
inward, so that its outer surface is concave, its inner convex. 
Structure.-This membrane is composed of three layers-an external (cuticu- 
lar), a middle (fibrous), and an internal (mucous). The cuticular lining is derived 
from the integument lining the meatus. The fibrous layer consists of fibrous and 
elastic tissues; some of the fibres radiate from near the centre to the circumference; 
others are arranged in the form of a dense circular ring around the attached margin 
of the membrane. The mucous lining is derived from the mucous lining of the 
tympanum. The vessels pass to the membrana tympani along the handle of the 
malleus and are distributed between its layers. 
Ossicles of the Tympanum (Fig. 546). 
The tympanum is traversed by a chain of movable bones three in number-the 
malleus, incus, and stapes. The former is attached to the membrana tympani, the 
latter to the fenestra ovalis, the incus being placed 
between the two, to both of which it is connected by 
delicate articulations. 
The Malleus, so named from its fancied resem- 
blance to a hammer, consists of a head, neck, and 
three processes-the handle or manubrium, the pro- 
cessus gracilis, and the processus brevis. 
The head is the large upper extremity of the 
bone; it is oval in shape, and articulates posteriorly 
with the incus, being free in the rest of its extent. 
The neck is the narrow, contracted part just be- 
neath the head, and below this is a prominence to 
which the various processes are attached. 
The manubrium is a vertical process of bone 
which is connected by its outer margin with the membrana tympani. It decreases 
in size toward its extremity, where it is curved slightly forward and flattened from 
within outward. On the inner side, near its upper end, is a slight projection into 
which the tendon of the Tensor tympani is inserted. 
The processus gracilis is a long and very delicate process which passes from the 
eminence below the neck forward and outward to the Glaserian fissure, to which it 
is connected by bone and ligamentous fibres. 
The processus brevis is a slight conical projection which springs from the root of 
the manubrium and lies in contact with the membrana tympani. 
The Incus has received its name from its supposed resemblance to an anvil, but 
it is more like a bicuspid tooth with two roots, which differ in length and are widely 
separated from each other. It consists of a body and two processes. 
Fig. 546. 
Free. brevis 
SZetf>es\ 
-I.cnRcu.Earfracess 
Cmrcc 
jEZea-oi 
The Small Bones of the Ear, seen from 
the outside (enlarged). 830 
ORGANS OF SENSE. 
The body is somewhat quadrilateral, but compressed laterally. On the anterior sur- 
face of its summit is a deeply concavo-convex facet, which articulates with the malleus; 
in the fresh state it is covered with cartilage and lined with synovial membrane. 
The two processes diverge from each other nearly at right angles. 
The short process, somewhat conical in shape, projects nearly horizontally back- 
ward, and is attached to the margin of the opening leading into the mastoid cells by 
ligamentous fibres. 
o 
The long process, longer and more slender than the preceding, descends nearly 
vertically behind and parallel to the handle of the malleus, and, bending inward, 
terminates in a rounded globular projection, the os orbiculare, or lenticular process, 
which is tipped with cartilage and articulates with the head of the stapes. In the 
foetus the os orbiculare exists as a separate bone, but becomes united to the long 
process of the incus in the adult. 
The Stapes, so called from its close resemblance to a stirrup, consists of a head, 
neck, two branches, and a base. 
The head presents a depression tipped with cartilage which articulates with the 
os orbiculare. 
The neck, the constricted part of the bone below the head, receives the insertion 
of the Stapedius muscle. 
The two branches (crura) diverge from the neck, and are connected at their 
extremities by a flattened, oval-shaped plate (the base), which forms the foot of the 
stirrup and is fixed to the margin of the fenestra ovalis by ligamentous fibres. 
Ligaments of the Ossicula.-These small bones are connected with each other 
and with the walls of the tympanum by ligaments, and moved by small muscles. 
The articular surfaces of the malleus and incus and the orbicular process of the 
incus and head of the stapes are covered with cartilage, connected together by deli- 
cate capsular ligaments, and lined by synovial membrane. The ligaments connect- 
ing the ossicula with the walls of the tympanum are four in number-two for the 
malleus, one for the incus, and one for the stapes. 
The anterior ligament of the malleus was formerly described by Sbmmerring as 
a muscle (Laxator tympani). It is now, however, believed by most observers to 
consist of ligamentous fibres only. It is attached by one extremity to the neck of 
the malleus, just above the processus gracilis, and by the other to the anterior wall 
of the tympanum close to the Glaserian fissure, some of its fibres being prolonged 
through the fissure. 
The suspensory ligament of the malleus is a delicate, round bundle of fibres 
which descends perpendicularly from the roof of the tympanum to the head of the 
malleus. 
The posterior ligament of the incus is a short, thick, ligamentous band which 
connects the extremity of the short process of the incus to the posterior wall of the 
tympanum, near the margin of the opening of the mastoid cells. 
The annular ligament of the stapes connects the circumference of the base of this 
bone to the margin of the fenestra ovalis. 
A suspensory ligament of the incus has been described by Arnold as descend- 
ing from the roof of the tympanum to the upper part of the incus near its articula- 
tion with the malleus. 
The muscles of the tympanum are two: 
Tensor tympani. 
Stapedius. 
The Tensor tympani, the largest, is contained in the bony canal above the osse- 
ous portion of the Eustachian tube, from which it is separated by the processus 
cochleariformis. It arises from the under surface of the petrous bone, from the 
cartilaginous portion of the Eustachian tube, and from the osseous canal in which 
it is contained. Passing backward through the canal, it terminates in a slender 
tendon which enters the tympanum and makes a sharp bend outward round the 
extremity of the processus cochleariformis, and is inserted into the handle of the 
malleus near its root. It is supplied by a branch from the otic ganglion. THE EAR. 
831 
The Stapedius-arises from the sides of a conical cavity hollowed out of the inte- 
rior of the pyramid: its tendon emerges from the orifice at the apex of the pyramid, 
and, passing forward, is inserted into the neck of the stapes. Its surface is aponeur- 
otic, its interior fleshy, and its tendon occasionally contains a slender bony spine, 
which is constant in some Mammalia. It is supplied by the tympanic branch of 
the facial nerve. 
Actions.-The Tensor tympani draws the membrana tympani inward, and thus 
heightens its tension. The Stapedius draws the head of the stapes backward, and 
thus causes the base of the bone to rotate on a vertical axis drawn through its own 
centre: in doing this the back part of the base would be pressed inward toward the 
vestibule, while the fore part would be drawn from it. It probably compresses the 
contents of the vestibule. 
The mucous membrane of the tympanum is thin, slightly vascular, and con- 
tinuous with the mucous membrane of the pharynx through the Eustachian tube. It 
invests the ossicula and the muscles and nerves contained in the tympanic cavity, 
forms the internal layer of the membrana tympani, covers the foramen rotundum, 
and is reflected into the mastoid cells, which it lines throughout. In the tympanum 
and mastoid cells this membrane is pale, thin, slightly vascular, and covered with 
ciliated epithelium. In the osseous portion of the Eustachian tube the membrane is 
thin, but in the cartilaginous portion it is very thick, highly vascular, covered with 
laminar ciliated epithelium, and provided with numerous mucous glands. 
The arteries supplying the tympanum are five in number. Two of them 
are larger than the rest-viz. the tympanic branch of the internal maxillary, which 
supplies the membrana tympani, and the stylo-mastoid branch of the posterior auric- 
ular, which supplies the back part of the tympanum and mastoid cells. The smaller 
branches are-the petrosal branch of the middle meningeal, which enters through 
the hiatus Fallopii, a branch from the ascending pharyngeal, which passes up the 
Eustachian tube, and the tympanic branch from the internal carotid, given off in 
the carotid canal and perforating the thin anterior wall of the tympanum. 
The veins of the tympanum terminate in the middle meningeal and pharyn- 
geal veins, and through these in the internal jugular. 
The nerves of the tympanum may be divided into-1, those supplying the 
muscles; 2, those distributed to the lining membrane; 3, branches communicating 
with other nerves. 
Nerves to Muscles.-The Tensor tympani is supplied by a branch from the otic 
ganglion; the Stapedius by the tympanic branch of the facial (Sommerring). 
The nerves distributed to the lining membrane are derived from the tympanic plexus. 
The communications which take place in the tympanum are between the tympa- 
nic branch of the glosso-pharyngeal with the sympathetic and with filaments derived 
from the intumescentia gangliformis of the facial. 
The tympanic branch of the glosso-pharyngeal (Jacobson's nerve) enters the 
tympanum by an aperture in its floor close to the inner wall, and ascends on to 
the promontory. It distributes branches to the fenestra rotunda, fenestra ovalis, 
and to the lining membrane of the tympanum and Eustachian tube, and divides 
into three branches of communication, which are contained in grooves on the prom- 
ontory. One of these arches forward and downward to the carotid canal to join the 
carotid plexus. A second runs forward and upward to join the greater superficial 
petrosal nerve as it lies in the hiatus Fallopii. The third branch runs upward 
through the substance of the petrous portion of the temporal bone. In its course 
it passes by the ganglionic enlargement of the facial nerve, and, receiving a con- 
necting filament from it, becomes the lesser superficial petrosal nerve, which joins 
the otic ganglion. 
The chorda tympani quits the facial near the stylo-mastoid foramen, enters the 
tympanum at the base of the pyramid, and arches forward across its cavity, between 
the handle of the malleus and long process of the incus, to the iter chordae anterius, 
through which it enters the canal of Huguier. It is invested by a reflection of the 
lining membrane of the tympanum. 832 
ORGANS OF SENSE. 
Internal Ear or Labyrinth. 
The Internal Ear is the essential part of the organ, receiving the ultimate dis- 
tribution of the auditory nerve. It is called the labyrinth., from the complexity of 
its shape, and consists of three parts-the vestibule, semicircular canals, and cochlea. 
It is formed by a series of cavities channelled out of the substance of the petrous 
bone, communicating externally with the cavity of the tympanum through the fenes- 
tra ovalis and rotunda, and internally with the' meatus auditorius internus, which 
contains the auditory nerve. Within the osseous labyrinth is contained the 
membranous labyrinth, upon which the ramifications of the auditory nerve are 
distributed. 
The Vestibule (Fig. 547) is the common central cavity of communication 
between the parts of the internal ear. It is situated on the inner side of the 
Fig. 547. 
Opencng 
-Bristle passed, through 
Foram. rotu/nd. 
Ov&rung of 
AqutzcLuctO'S Cochlea 
The Osseous Labyrinth laid open (enlarged). 
tympanum, behind the cochlea, and in front of the semicircular canals. It is some- 
what ovoidal in shape from before backward, flattened from within outward, and 
measures about one-fifth of an inch from before backward as well as from above 
downward, being narrower from without inward. On its outer or tympanic wall is 
the fenestra ovalis, closed in the recent state by the base of the stapes, and its 
annular ligament. On its inner rvall, at the fore part, is a small circular depression, 
fovea hemispherica, which is perforated at its anterior and inferior part by several 
minute holes (macula cribrosa) for the passage of the filaments of the auditory 
nerve; and behind this depression is a vertical ridge, the pyramidal eminence (crista 
vestibuli). At the hinder part of the inner wall is the orifice of the aquceductus 
vestibuli, which extends to the posterior surface of the petrous portion of the tem- 
poral bone. It transmits a small vein, and, according to some, contains a tubular 
prolongation of the lining membrane of the vestibule, which ends in a cul-de-sac 
between the layers of the dura mater within the cranial cavity. On the upper wall 
or roof is a transversely-oval depression, fovea semi-elliptica, separated from the 
fovea hemispherica by the pyramidal eminence already mentioned. Behind, the 
semicircular canals open into the vestibule by five orifices. In front is a large oval 
opening which communicates with the scala vestibuli of the cochlea by a single ori- 
fice, apertura scalce vestibuli cochlea;. 
The Semicircular Canals are three bony canals situated above and behind the THE EAR. 
833 
vestibule. They are of unequal length, compressed from side to side, and describe 
the greater part of a circle. They measure about one-twentieth of an inch in diam- 
eter, and each presents a dilatation at one end, called the ampulla, which measures 
more than twice the diameter of the tube. These canals open into the vestibule by 
five orifices, one of the apertures being common to two of the canals. 
The superior semicircular canal is vertical in direction, and stretches across 
the petrous portion of the temporal bone at right angles to its posterior surface; 
its arch forms a round projection on the anterior surface of the petrous bone. It 
describes about two-thirds of a circle. Its outer extremity, which is ampullated, 
commences by a distinct orifice in the upper part of the vestibule; the opposite 
end of the canal, which is not dilated, joins with the corresponding part of the 
posterior canal and opens by a common orifice with it in the back part of the 
vestibule. 
The posterior semicircular canal, also vertical in direction, is directed backward 
nearly parallel to the posterior surface of the petrous bone: it is the longest of the 
three, its ampullated end commencing at the lower and back part of the vestibule, 
its opposite end joining to form the common canal already mentioned. 
The external or horizontal canal is the shortest of the three, its arch being 
directed outward and backward; thus each semicircular canal stands at right angles 
to the other two. Its ampullated end corresponds to the upper and outer angle of 
the vestibule, just above the fenestra ovalis; its opposite end opens by a distinct 
orifice at the upper and back part of the vestibule. 
The Cochlea bears some resemblance to a common snail-shell: it forms the 
anterior part of the labyrinth, is conical in form, and placed almost horizontally in 
front of the vestibule; its apex is directed forward and outward toward the upper 
and front part of the inner wall of the tympanum; its base corresponds with the 
anterior depression at the bottom of the internal auditory meatus, and is perforated 
by numerous apertures for the passage of the cochlear branch of the auditory 
nerve. It measures about a quarter of an inch in length, and its breadth toward 
the base is about the same. It consists of a conical-shaped central axis, the modi- 
olus or columella; of a canal wound spirally round the axis for two turns and a 
half from the base to the apex ; and of a delicate lamina (the lamina spiralis) 
contained within the canal, which follows its windings and partially subdivides it 
into two. 
The central axis, or modiolus, is conical in form, and extends from the base to 
the apex of the cochlea. Its base is broad, corresponds with the first turn of the 
cochlea, and is perforated by numerous orifices, which transmit filaments of the 
cochlear branch of the auditory nerve; the axis diminishes rapidly in size in the 
second coil, and terminates within the last half-coil, or cupola, in an expanded, 
delicate, bony lamella which resembles the half of a funnel divided longitudinally, 
and is called the infundibulum; the broad part of this funnel is directed toward 
the summit of the cochlea, and blends with the cupola or last half-turn of the 
spiral canal of the cochlea. At this point the two larger scalse of the cochlea, the 
scala tympani and scala vestibuli, communicate by an opening called the helico- 
trema. The outer surface of the modiolus forms part of the wall of the spiral 
canal, and is dense in structure; but its centre is channelled, as far as the last 
half-coil, by numerous branching canals, which transmit nervous filaments in 
regular succession into the canal of the cochlea or on to the surface of the lamina 
spiralis. One of these, larger than the rest, occupies the centre of the modiolus, 
and is named the canalis centralis modioli; it extends from the base to the extrem- 
ity of the modiolus, and transmits a small nerve and artery (arteria centralis 
modioli). 
The spiral canal (Fig. 548) takes two turns and a half round the modiolus. It 
is about an inch and a half in length, measured along its outer wall, and diminishes 
gradually in size from the base to the summit, where it terminates in a cul-de-sac, 
the cupola, which forms the apex of the cochlea. The commencement of this canal 
is about the tenth of an inch in diameter; it diverges from the modiolus toward the 834 
ORGANS OF SENSE. 
tympanum and vestibule, and presents three openings: one, the fenestra rotunda, 
communicates with the tympanum; in the recent state this aperture is closed by a 
membrane, the membrana tympani secundaria. Another aperture, of an oval form, 
enters the vestibule. The third is the aperture of the aquceductus cochlece, leading 
Fig. 548. 
The Cochlea laid open (enlarged). 
to a minute funnel-shaped canal which opens on the basilar surface of the petrous 
bone and transmits a small vein. 
The interior of the spiral canal (Fig. 549) is partially divided into two, in the 
dry state, by a thin bony plate, the lamina spiralis [l. s.], which consists of two 
thin lamellae of bone, between which are numerous canals for the passage of nerve- 
fibres. This lamina projects from the modiolus into the canal, but does not reach 
more than halfway toward the outer wall of the tube. From its extremity a thin 
membrane extends to the outer wall, and completes the division of the canal into 
an upper compartment, the scala vestibuli [s. V.], and a lower one, the scala tym- 
yani [s. T.]. By a second membrane a portion of the upper of these two canals is 
cut off from the rest, constituting the scala media [s. M.J. The lamina spiralis ends 
Fig. 549. 
Longitudinal Section of the Cochlea, showing the relations of the scalee, the ganglion spirale, etc.: s. v., scala 
vestibuli; s. t., scala tympani: s. m.. scala media; l. s., ligamentum spirale; g. s., ganglion spirale. [The 
membrane of Reissner is intentionally omitted in the second turn to the right. See note (■) on p. 835.] 
above in a hook-shaped process, which partly bounds the helicotrema. At the point 
where the osseous lamina is attached to the modiolus is a small canal which winds 
round the modiolus, and was denominated by Rosenthal the canalis spiralis modioli: 
it is occupied by a swelling of the cochlear nerve, in which ganglion-cells are found, THE EAR. 
835 
the ganglion spirale [g. S.], from which the nerves pass to the osseous lamina and 
organ of Corti. 
The osseous lamina, as above stated, extends only part of the distance between 
the modiolus and the outer bony wall of the cochlea. Near its outer end the peri- 
osteum on the upper or vestibular surface of the lamina swells up into an elevation 
which is called the limbus laminae spiralis ("denticulate lamina" of Todd and Bow- 
man). The lamina spiralis terminates in a grooved extremity, the sulcus spiralis, 
which presents the form of the letter C5 : the upper part of the letter, being formed 
by the overhanging extremity of the limbus, is named the labium vestibulare; the 
lower part, prolonged and tapering, is called the labium tympanicum (Fig. 550). 
Fig. 550. 
SCALA MEDIA 
MEM BRANE OF C ORTJ 
SULCUS SPIRALIS 
ORGAN OF CORT[ 
MEMBRANABASIl'ARIS?' 
Floor of Scala Media, showing the Organ of Corti, etc. [Only part of the Membrane of Reissner is represented.] 
From the labium tympanicum a thin membrane extends over to the bony wall of 
the cochlea, completing the scala tympani. This membrane is called the membrana 
basilaris. At its outer attachment it swells out so as to form a thick triangular 
structure which was regarded as a muscle by Todd and Bowman (cochlearis), but is 
now recognized as ligamentous-the lig amentum spirale. Between the labium ves- 
tibulare and the attachment of the membrane of Reissner, presently to be described, 
a very delicate membrane extends over to the outer wall of the cochlea, running 
nearly parallel to the membrana basilaris. It was described by Corti, and covers 
over the organ, which is called after his name, and is therefore called membrana tec- 
toria, or membrane of Corti. Farther inward, near the commencement of the limbus 
laminae spiralis, another delicate membrane, the membrane of Reissner, is attached 
to the vestibular surface of the periosteum of the osseous lamina and stretches across 
to the outer wall of the cochlea. The canal which lies below the osseous lamina and 
membrana basilaris is the scala tympani; that which is bounded by the osseous lam- 
ina and membrane of Reissner, the scala vestibuli ; wdiile the space between the mem- 
brane of Reissner and membrana basilaris is generally described as the scala media, 
canalis membranacea, or canalis cochlece; and this is the nomenclature which will be 
used here. Others, however, apply the name canalis cochlece only to the canal lying 
between the membrane of Reissner and the "membrane of Corti," which contains 
no object for description, while the space lying between the "membrane of Corti " 
and the membrana basilaris is described by itself as a fourth canal-the ductus coch- 
learis or ductus auditorius.1 The latter is the space in which the organ of Corti2 is 
contained. This organ (Fig. 550) is situated upon the membrana basilaris, and 
appears at first sight as a papilla winding spirally with the turns of this membrane 
1 In reading the older descriptions of the organ of hearing the student must bear in mind that 
the membranes bounding the ductus auditorius, together with the organ contained between them, 
were described together as the "lamina spiralis membranacea," while the membrane of Reissner 
was not recognized, the parts being, in fact, as shown in the second turn of the cochlea on the right 
hand of Fig. 549. 
2 Corti's original paper is in the Zeitschrift f. Wissen. Zool., iii. 109. 836 
ORGANS OF SENSE. 
throughout the whole length of the cochlea, from which circumstance it has been 
designated the papilla spiralis. More accurately viewed, it is seen to be composed 
of a remarkable arrangement of cells which may be likened to the keyboard of a 
pianoforte. Of these cells, the two central ones are rod-like bodies, and are called 
the inner and outer rods of Corti. They are placed erect on the basilar membrane 
at some little distance from each other, the space between them being denominated 
the zona arcuata ; they are inclined toward each other, so as to meet at their oppo- 
site extremities and form a series of arches roofing over the zona arcuata, thus form- 
ing a minute tunnel between them and the basilar membrane, which ascends spirally 
through the whole length of the cochlea.. They are estimated at over three thousand 
in number. 
The inner rods, which are more numerous than the outer ones, rest on the basilar 
membrane close to the labium tympanicum ; they project obliquely forward and out- 
ward, and terminate above in expanded extremities which resemble in shape the head 
of the human ulna with its sigmoid cavity, coronoid and olecranon processes. On the 
outer side of the rod, in the angle formed between it and the basilar membrane, is a 
protoplasmic cell, whilst on the inner side is a row of epithelial cells surmounted by 
a brush of fine, stiff, hair-like processes, these cells being continuous with the cubical 
cells lining the sulcus spiralis. 
The outer rods also rest by a broad foot on the basilar membrane; they incline 
forward and inward, and their upper extremity resembles the head and bill of a 
swan, the head fitting into the concavity-the analogue of the sigmoid cavity-of 
one or more of the internal rods, and the bill resting against the phalanges of the 
lamina reticularis, presently to be described. 
In the head of these outer rods is an oval portion where the fibres of which the 
rod appears to be composed are deficient, and which stains more deeply with car- 
mine than the rest of the rod. This is supposed to represent the nucleus of the 
cell from which the rod was originally developed. At the base of the rod, on its 
internal side-that is to say, in the angle formed by the rod with the basilar mem- 
brane-is a similar protoplasmic cell to that found on the outer side of the base of 
the inner rod; whilst external to the outer rod are three or four successive rows of 
epithelial cells, more elongated than those found on the internal side of the inner 
rod, but like them furnished with minute hairs or cilia. These are termed the 
outer hair-cells, in contradistinction to the inner set, which are termed the inner 
hair-cells. They are attached by their bases to the basilar membrane, whilst from 
the opposite extremity'a brush of hairs or cilia projects through the reticular mem- 
brane. They are continuous externally with the cubical cells on the lateral part of 
the basilar membrane. 
The reticular lamina or membrane of Kolliker is a delicate framework perforated 
by rounded holes. It extends from the inner rods of Corti to the external row of 
the outer hair-cells, and is formed by several rows of " minute fiddle-shaped cuticu- 
lar structures" called phalanges, between which are holes for the projection of the 
ciliae of the outer hair-cells. 
Covering over these structures, but not touching them, is the membrana tectoria, 
or membrane of Corti, which is attached to the vestibular surface of the lamina 
spiralis close to the attachment of the membrane of Reissner; it courses over the 
denticulate lamina, and, passing outward parallel to the basilar membrane, is blended 
with the ligamentum spirale on the outer wall of the spiral canal.1 
The inner surface of the osseous labyrinth is lined by an exceedingly thin fibro- 
serous- membrane, analogous to the periosteum, from its close adhesion to the inner 
surfaces of these cavities, and performing the office of a serous membrane by its free 
surface. It lines the vestibule, and from this cavity is continued into the semicir- 
cular canals and the scala vestibuli of the cochlea, and through the helicotrema into 
the scala tympani. A delicate tubular process is prolonged along the aqueduct of 
the vestibule to the inner surface of the dura mater. This membrane is continued 
across the fenestra ovalis and rotunda, and consequently has no communication with 
1 In Fig. 550 only t*he inner half of the membrane is represented. THE EAR. 
837 
the lining membrane of the tympanum. Its attached surface is rough and fibrous 
and closely adherent to the bone; its free surface is smooth and pale, covered with 
a layer of epithelium, and secretes a thin, limpid fluid, the aqua labyrinthi, liquor 
Cotunnii, or perilymph (Blainville). 
The scala media is closed above and below. The upper blind extremity is 
attached to the cupola at the upper part of the helicotrema; the lower end fits into 
the angle at the commencement of the osseous lamina on the floor of the vestibule. 
Near this blind extremity the scala media receives the canalis reunions (Fig. 551), 
a very delicate canal by which the ductus cochlearis is brought into continuity with 
the saccule. 
The Membranous Labyrinth. 
The membranous labyrinth (Fig. 551) is a closed membranous sac [belonging to 
the lymphatic system], containing fluid, on the walls of which the ramifications of 
the auditory nerve are distrib- 
uted. It has the same general 
form as the vestibule and semi- 
circular canals, in which it is 
enclosed, but is considerably 
smaller, and separated from 
their lining membrane by the 
perilymph. 
The vestibular portion con- 
sists of two sacs, the utricle and 
the saccule. 
The utricle [diminutive of 
uter, a bag or bottle] is the 
larger of the two, of an oblong 
form, compressed laterally, and 
occupies the upper and back 
part of the vestibule, lying in 
contact with the fovea semi- 
elliptica. Numerous filaments 
of the auditory nerve are distributed on the wall of this sac, and its cavity commu- 
nicates behind with the membranous semicircular canals by five orifices. 
The saccule is the smaller of the two vestibular sacs; it is globular in form, lies 
in the fovea hemispherica near the opening of the vestibular scala of the cochlea, 
and receives numerous nervous filaments which enter from the bottom of the depres- 
sion in which it is contained. Its cavity is apparently distinct from that of the 
utricle. 
The membranous semicircular canals are about one-third the diameter of the 
osseous canals, but in number, shape, and general form they are precisely similar; 
they are hollow, and open by five orifices into the utricle, one opening being com- 
mon to two canals. Their ampullae are thicker than the rest of the tubes, and 
nearly fill the cavities in which they are contained. 
The membranous labyrinth is held in its position by numerous fibrous bands 
which stretch across the space between the membranous and bony labyrinths. 
These fibrous bands convey the blood-vessels and nervous filaments distributed to 
the utricle, to the saccule, and to the ampulla of each canal. The nerves enter 
the vestibule through the minute apertures on its inner wall. 
Structure.-The wall of the membranous labyrinth is semi-transparent and con- 
sists of three layers. The outer layer is a loose and flocculent structure, apparently 
composed of ordinary fibrous tissue, containing blood-vessels and numerous pig- 
ment-cells analogous to those in the pigment-coat of the retina. The middle layer, 
thicker and more transparent, bears some resemblance to the hyaloid membrane, 
but it presents on its internal surface numerous papilliform projections, and in parts 
marks of longitudinal fibrillation and elongated nuclei on the addition of acetic acid. 
Fig. 551. 
CANAL1S REUNIENS 
The Membranous Labyrinth (enlarged 4 diameters). 838 
ORGANS OF SENSE. 
The inner layer is formed of polygonal nucleated epithelial cells, which secrete the 
endolymph. 
The endolymph {liquor Scarpoe) is a limpid serous fluid which fills the mem- 
branous labyrinth; in composition it closely resembles the perilymph. 
The otoliths are two small rounded bodies, consisting of a mass of minute crys- 
talline grains of carbonate of lime, held together in a mesh of delicate fibrous tissue, 
and contained in the wall of the utricle and saccule opposite the distribution of the 
nerves. A calcareous material is also, according to Bowman, sparingly scattered in 
the cells lining the ampulla of each semicircular canal. 
The arteries of the labyrinth are the internal auditory, from the basilar; the 
stylo-mastoid, from the posterior auricular; and occasionally branches from the 
occipital. The internal auditory divides at the bottom of the internal meatus into 
two branches-cochlear and vestibular. 
The cochlear branch subdivides into from twelve to fourteen twigs, which traverse 
the canals in the modiolus, and are distributed, in the form of a capillary network, 
in the substance of the lamina spiralis. 
The vestibular branches accompany the nerves, and are distributed, in the form 
of a minute capillary network, in the substance of the membranous labyrinth. 
The veins (auditory) of the vestibule and semicircular canals accompany the 
arteries, and, receiving those of the cochlea at the base of the modiolus, terminate 
in the superior petrosal sinus. 
The auditory nerve, the special nerve of the sense of hearing, divides at the 
bottom of the internal auditory meatus into two branches-the cochlear and vestib- 
ular. The trunk of the nerve, as well as the branches, contains numerous gan- 
glion-cells with caudate prolongations. 
The vestibular nerve, the posterior of the two, divides into three branches-supe- 
rior, middle, and inferior. 
The superior vestibular branch, the largest, divides into numerous filaments, 
which pass through minute openings at the upper and back part of the cul-de-sac 
at the bottom of the meatus, and, entering the vestibule, are distributed to the 
utricle and to the ampulla of the external and superior semicircular canals. 
The middle vestibular branch consists of numerous filaments, which enter the 
vestibule by a smaller cluster of foramina placed below those above mentioned, and 
which correspond to the bottom of the fovea hemispherica; they are distributed to 
the saccule. 
The inferior and smallest branch passes backward in a canal behind the foramina 
for the nerves of the saccule, and is distributed to the ampulla of the posterior semi- 
circular canal. 
The nervous filaments enter the ampullary enlargements at a deep depression 
seen on their external surface, with a corresponding elevation when seen from 
within, the nerve-fibres ending in loops and in free extremities. In the utricle 
and saccule the nerve-fibres spread out, some blending with the calcareous matter, 
others radiating on the inner surface of the wall of each cavity, becoming blended 
with a layer of nucleated cells and terminating in a thin fibrous film. 
The cochlear nerve divides into numerous filaments at the base of the modiolus, 
which ascend along its canals, and then, bending outward at right angles, pass 
between the plates of the bony lamina spiralis close to its tympanic surface. 
Between the plates of the spiral lamina the nerves form a plexus which con- 
tains ganglion-cells forming the ganglion spirale. From this ganglion delicate 
filaments pass between the layers of the osseous lamina to the sulcus spirale, and 
pass outward to the organ of Corti. Their exact termination is uncertain. Wal- 
deyer describes them as collected into two groups, one group ending in the outer 
and the other in the inner hair-cells. Organs of Digestion. 
o o 
THE apparatus for the digestion of the food consists of the alimentary canal and 
of certain accessory organs. 
The Alimentary Canal is a musculo-membranous tube about thirty feet in 
length, extending from the mouth to the anus and lined throughout its entire 
extent by mucous membrane. It has received different names in the various parts 
of its course. At its commencement, the mouth, we find provision made for the 
mechanical division of the food (mastication), and for its admixture with a fluid 
secreted by the salivary glands (insalivation); beyond this are the organs of deglu- 
tition, the pharynx and the oesophagus, which convey the food into that part of the 
alimentary canal (the stomach) in which the principal chemical changes occur and in 
which the reduction and solution of the food take place; in the small intestines the 
nutritive principles of the food (the chyle) are separated, by its admixture with the 
bile and pancreatic fluid, from that portion which passes into the large intestine, 
most of which is expelled from the system. 
Alimentary Canal. 
Duodenum. 
Jejunum. 
Ileum. 
Mouth. 
Pharynx. 
(Esophagus. 
Stomach. 
Small intestine . 
Caecum. 
Colon. 
Rectum. 
Large intestine . 
Accessory Organs. 
Teeth. 
Salivary glands 
Parotid. 
Submaxillary. 
Sublingual. 
Liver. 
Pancreas. 
Spleen. 
The Mouth (oral or buccal cavity) (Fig. 552) is placed at the commencement of 
the alimentary canal; it is a nearly oval-shaped cavity in which the mastication 
of the food takes place. It is bounded in front by the lips ; laterally by the cheeks 
and the alveolar processes of the upper and lower jaws ; above by the hard palate 
and teeth of the upper jaw; below by the tongue and by the mucous membrane 
stretched between the under surface of that organ and the inner surface of the 
jaws, and by the teeth of the lower jaw; behind by the soft palate and fauces. 
The mucous membrane lining the mouth is continuous with the integument at 
the free margin of the lips, and with the mucous lining of the fauces behind; it is 
of a rose-pink tinge during life, and very thick where it covers the hard parts bound- 
ing the cavity. It is covered by scaly stratified epithelium. 
The Lips are two fleshy folds which surround the orifice of the mouth, formed 
externally of integument and internally of mucous membrane, between which are 
found the Orbicularis oris muscle, the coronary vessels, some nerves, areolar tissue 
and fat, and numerous small labial glands. The inner surface of each lip is con- 
nected in the middle line to the gum of the corresponding jaw by a fold of mucous 
membrane, the frcenum labii superioris and inferior is, the former being the larger 
of the two [and can be well appreciated by pressing the tip of the tongue between 
the upper lip and the teeth]. 
The labial glands are situated between the mucous membrane and the Orbicula- 
839 840 
ORGANS OF DIGESTION. 
ris oris, around the orifice of the mouth. They are rounded in form, about the size 
of small peas, their ducts opening by small orifices upon the mucous membrane. In 
structure they resemble the other salivary glands. 
The Cheeks form the sides of the face and are continuous in front with the lips. 
They are composed externally of integument, internally of mucous membrane, and 
between the two of a muscular 
stratum, besides a large quan- 
tity of fat, areolar tissue, ves- 
sels, nerves, and buccal glands. 
The mucous membrane lin- 
ing the cheek is reflected above 
and below upon the gums, and 
is continuous behind with the 
lining membrane of the soft 
palate. Opposite the second 
molar tooth of the upper jaw 
is a papilla, the summit of 
which presents the aperture of 
the duct of the parotid gland. 
The principal muscle of the 
cheek is the Buccinator; but 
numerous other muscles enter 
into its formation-viz. the 
Zygomatici, Masseter, and Pla- 
tysma myoides. 
The buccal glands are placed 
between the mucous membrane 
and Buccinator muscle: they 
are similar in structure to the 
labial glands, but smaller. Two 
or three of larger size than the 
rest are placed between the 
Masseter and Buccinator mus- 
cles ; their ducts open into the 
mouth opposite the last molar 
tooth. They are called molar 
glands. 
The Gums are composed of 
a dense tissue closely 
connected to the periosteum of the alveolar processes, and surrounding the necks of 
the teeth. They are covered by smooth and vascular mucous membrane, which is 
remarkable for its limited sensibility. Around the necks of the teeth this mem- 
brane presents numerous fine papillae, and from this point it is reflected into the 
alveolus, where it is continuous with the periosteal membrane lining that cavity. 
Fig. 552. 
O/icntny 
Nerval duct 
Bristle 
passed through 
St&no's d'UciJ 
Sectional View of me Nose, Mouth, Pharynx, etc. 
THE TEETH. 
The human subject is provided with two sets of teeth, which make their appear- 
ance at different periods of life. The first set appear in childhood, and are called 
the temporary, deciduous, or milk teeth. The second set, which also appear at an 
early period, continue until old age, and are named permanent. 
The temporary teeth are twenty in number-four incisors, two canine, and four 
molars in each jaw. 
The teeth are thirty-two in number-four incisors (two central and 
two lateral), two canine, four bicuspids, and six molars in each jaw. 
General Characters.-Each tooth consists of three portions: the crown, or THE TEETH. 
841 
body, projecting above the gum; the root, or fang, entirely concealed within the 
alveolus; and the neck, the constricted portion, between the other two. 
The roots of the teeth are firmly implanted within the alveoli; these depressions 
are lined with periosteum, which is reflected on to the tooth at the point of the fang, 
and covers it as far as the neck. At the margin of the alveolus the periosteum 
becomes continuous with the fibrous structure of the gums. 
Permanent Teeth. 
The Incisors, or cutting teeth, are so named from their presenting a sharp cut- 
ting edge adapted for cutting the food. They are eight in number, and form the 
four front teeth in each jaw. 
The crown is directed vertically, and is wedge-like in form, being bevelled at 
the expense of its posterior surface, so as to terminate in a sharp horizontal cutting 
edge, which before being subject to attrition presents three small prominent points. 
It is convex, smooth, and highly polished in front; slightly concave behind, where 
it is frequently marked by slight longitudinal furrows. 
The neck is constricted. 
The fang is long, single, conical, transversely flattened, thicker before than 
behind, and slightly grooved on each side in the longitudinal direction. 
The incisors of the upper jaw are altogether larger and stronger than those 
of the lower jaw. They are directed obliquely downward and forward. The two 
central ones are larger than the two lateral,, and their free edges are sharp and 
chisel-like, being bevelled at the expense of their posterior edge: the root is more 
rounded. 
The incisors of the lower jaw are smaller than the upper: the two central ones 
are smaller than the two lateral, and are the smallest of all the incisor teeth. 
The Canine Teeth (cuspidati) are four in number, two in the upper and two in 
the lower jaw, one being placed behind each lateral incisor. They are larger and 
stronger than the incisors, especially the root, which sinks deeply into the jaw and 
causes a well-marked prominence upon its surface. 
The crown is large and conical, very convex in front, a little hollowed and 
uneven posteriorly, and tapering to a blunted point or cusp which rises above the 
level of the other teeth. 
The root is single, but longer and thicker than that of the incisors, conical in 
form, compressed laterally, and marked by a slight groove on each side. 
The upper canine teeth (vulgarly called eye-teeth) are larger and longer than the 
two lower, and situated a little behind them. 
The lower canine teeth are placed in front of the upper, so that their summits 
correspond to the interval between the upper canine tooth and the neighboring 
incisors on each side. 
The Bicuspid. Teeth (premolars, small or false molars) are eight in number- 
four in each jaw, two being placed immediately behind each of the canine teeth. 
They are smaller and shorter than the canine. 
The crown is compressed from without inward and surmounted by two pyramidal 
eminences or cusps separated by a groove ; hence their name, bicuspidati. The outer 
of these cusps is larger and more prominent than the inner. 
The neck is oval. 
The root is generally single, compressed, and presents a deep groove on each 
side, which indicates a tendency in the root to become double. The apex is gene- 
rally bifid. 
The upper bicuspids are larger, and present a greater tendency to the division of 
their roots, than the lower; this is especially marked in the second upper bicuspid. 
The Molar Teeth (gnulticiispidati, true or enlarged molars) are the largest of the 
permanent set, and are adapted, from the great breadth of their crowns, for grind- 
ing and pounding the food. They are twelve in number-six in each jaw, three 
being placed behind each of the posterior bicuspids. 842 
ORGANS OF DIGESTION. 
The crown is nearly cubical in form, rounded on each of its lateral surfaces, 
flattened in front and behind, the upper surface being surmounted by four or five 
Fig. 553. 
Upper Ja.w 
Molars 
Bicuspids 
Canine 
Incisors 
Wisdom taath 
-Fang 
-Neck 
-Crown 
Lower Ja-w 
Crown 
Nc-ek 
Fang 
Wisdom tootle 
Molars 
Bicuspids 
Canine 
Incisors 
The Permanent Teeth, external view. 
tubercles or cusps (four in the upper, five in the lower molars) separated from each 
other by a crucial depression; hence their name, multicuspidati. 
The neck is distinct, large, and rounded. 
The root is subdivided into from two to five fangs, each of which presents an 
aperture at its summit. 
The first molar tooth is the largest and broadest of all; its crown has usually 
five cusps, three outer and two in- 
ner. In the upper jaw the root 
consists of three fangs, widely sep- 
arated from each other, two being 
external, the other internal. 
The latter is the largest and 
longest, slightly grooved, and some- 
times bifid. In the lower jaw the 
root consists of two fangs, one be- 
ing placed in front, the other be- 
hind : they are both compressed 
from before backward, and grooved 
on their contiguous faces, indicating 
a tendency to division. 
The second molar is a little 
smaller than the first. 
The crown has four cusps in 
the upper and five in the lower 
jaw. 
The root has three fangs in the 
upper jaw and two in the lower, 
the characters of which are similar to the preceding tooth.. 
[Fig. 554. 
Showing the "occlusion" or apposition of the permanent 
teeth (Litch).] 843 
THE TEETH. 
The third molar tooth is called the wisdom tooth (dens sapiential from its late 
appearance through the gum. It is smaller than the others, and its axis is directed 
inward. 
The crown is small and rounded and furnished with three tubercles. 
The root is generally single, short, conical, slightly curved, and grooved so as to 
present traces of a subdivision into three fangs in the upper and two in the lower jaw. 
[Fig. 554 well shows the "occlusion" or apposition of the teeth. It will be 
noticed that the upper teeth overlap the lower ones in front, while the surfaces of 
the molar teeth are in contact. No tooth is exactly apposed to its fellow in the 
other jaw, but each one has a bearing on two opposite teeth, except in the case of 
the wisdom teeth (third molars). This contributes to efficient mastication, and when 
one tooth is lost its fellow of the opposite jaw still partially retains its usefulness.] 
Temporary Teeth. 
The Temporary, or Milk Teeth, are smaller, but resemble in form those of the 
permanent set. The hinder of the two temporary molars is the largest of all the 
milk teeth, and is succeeded by the 
second permanent bicuspid. The 
first upper molar has only three 
cusps-two external, one internal; 
the second upper molar has four 
cusps. The first lower molar has 
four cusps; the second lower molar 
has five. The fangs of the tempo- 
rary molar teeth are smaller and 
more diverging than those of the 
permanent set, but in other respects 
bear a strong resemblance to them. 
Fig. 555. 
Molars 
Upper <Jcfw 
Canine 
Jncisorft 
-Fang 
-Neck 
-Crown, 
Lower Ja.w 
Fig. 556. 
Crown, 
Neck 
-Fany 
-Crown 
•Nech: 
-lang 
Molars 
Canine 
Incisors 
The Temporary, or Milk Teeth, external view. 
Vertical Section of a Molar Tooth, 
Structure.-On making a vertical section of a tooth (Fig. 556) a hollow cavity 
will be found in the interior. This cavity is situated at the base of the crown, and 
is continuous with a canal which traverses the centre of each fang and opens by a 
minute orifice at its extremity. The shape of the cavity corresponds somewhat 
with that of the tooth ; it forms what is called the pulp-cavity, and contains a soft, 
highly vascular, and sensitive substance, the dental pulp. The pulp consists of a 
loose connective tissue and cells; it is richly supplied with vessels and nerves, 
which enter the cavity through the small aperture at the point of each fang. The 
cells of the pulp are partly found permeating the connective tissue, and partly 
arranged as a layer on the wall of the pulp-cavity. These latter cells are of two 
kinds: some, columnar in shape, are named the odontoblasts of Waldeyer, and will 
be referred to hereafter; others, fusiform in shape, are wedged in between the colum- 
nar cells, and have two fine processes, the outer or distal one passing into a den- 
tine tubule, the inner being continuous with the processes of the connective-tissue 
cells of the pulp-matrix. According to some anatomists the processes of the odon- 
toblasts are also continued into the dentine tubuli. 
The solid portion of the tooth consists of three distinct structures-viz. the 844 
ORGANS OF DIGESTION. 
proper dental substance, which forms the larger portion of the tooth, the ivory, or 
dentine; a layer which covers the exposed part of the crown, the enamel; and a 
thin layer, which is disposed on the surface of the fang, the cement, or crusta 
petrosa. 
The Ivory, or Dentine (Fig. 557), forms the principal mass of a tooth; in its 
central part is the cavity enclosing the pidp. It is a modification of osseous tissue, 
from which it differs, however, in structure and chemical composition. On exam- 
ination with the microscope it is seen to consist of a number of minute wavy and 
branching tubes having distinct parietes. They are called the dental tubuli, and 
are imbedded in a dense homogeneous substance, the inter tubular tissue. 
The dental tubuli are placed parallel with one another, and open at their inner 
ends into the pulp-cavity. In their course to the periphery they present two or 
Fig. 558. 
Fig. 557. 
-Crown 
-Neck 
-Fang 
Vertical Section of a Bicuspid Tooth (magnified). 
Canine Tooth of Man, presenting a transverse section of a 
portion of the root: 1, cement with large lacunse and par- 
allel striae; 2, interglobular spaces: 3, dental tubules 
(magnified 300 diams.). 
three curves, and are twisted on themselves in a spiral direction. The direction of 
these tubes varies; they are vertical in the upper portion of the crown, oblique in 
the neck and upper part of the root, and toward the lower part of the root they are 
inclined downward. The tubuli, at their commencement, are about of an inch 
in diameter; in their course they divide and subdivide dichotomously, so as to give 
to the cut surface of the dentine a striated appearance. From the sides of the tubes, 
especially in the fang, ramifications of extreme minuteness are given off, which join 
together in loops in the intertubular substance or terminate in small dilatations from 
which branches are given off. Near the periphery of the dentine the finer ramifica- 
tions of the tubuli terminate in a layer of irregular branched spaces which commu- 
nicate with each other. These are called the interglobular spaces of Czermak or the 
granular layer of Purkinje (Fig. 558). The dental tubuli have comparatively thick 
walls, and contain slender cylindrical prolongations from the cells of the pulp-tissue, 
first described by Mr. Tomes, and named Tomes's fibres or dentinal fibres. These THE TEETH. 
845 
dentinal fibres are analogous to the soft contents of the canaliculi of bone. Between 
Tomes's fibres and the ivory of the canals there is an elastic homogeneous membrane 
which resists the action of acids-the dentinal sheath of Neumann. 
The intertubular substance is translucent, finely granular, and contains the chief 
part of the earthy matter of the dentine. After the earthy matter has been 
removed by steeping a tooth in weak acid, the animal basis remaining may be 
torn into laminse which run parallel with the pulp-cavity across the direction of the 
tubes. A section of dentine often displays a series of somewhat parallel lines- 
the incremental lines of Salter. These lines are composed of a number of masses 
of imperfectly calcified dentine arranged in layers. ' In consequence of the imper- 
fection in the calcifying process little irregular cavities are left, termed interglob- 
ular spaces, similar to those in the granular layer, but larger, and have received 
their name from the fact that they are surrounded by minute' nodules or globules 
of dentine. 
Other curved lines may be seen parallel to the surface. These are the lines of 
Schreger, and are due to the optical effect of simultaneous curvature of the dentinal 
fibres. 
Chemical Composition.-According to Berzelius and Bibra, dentine consists 
of 28 parts of animal and 72 of earthy matter. The animal matter is resolvable 
by boiling into gelatin. The earthy matter consists of phosphate of lime, car- 
bonate of lime, a trace of fluoride of calcium, phosphate of magnesia, and other 
salts. 
The Enamel is the hardest and most compact part of a tooth, and forms a thin 
crust over the exposed part of the crown as far as the commencement of the fang. 
It is thickest on the grinding surface of the crown until worn away by attrition, 
and becomes thinner toward the neck. It consists of a congeries of minute hex- 
agonal rods. They lie parallel with one another, resting by one extremity upon the 
dentine, which presents a number of minute depressions for their reception, and 
forming the free surface of the crown by the other extremity. These fibres are 
directed vertically on the summit of the crown, horizontally at the sides; they are 
about the of an inch in diameter, and pursue a more or less wavy course. 
The enamel is marked by a series of undulating lines, which cross each other or 
"decussate;" these lines are doubtless formed by the variation in the course of the 
enamel-rods. Another series of lines, colored brown, probably from the presence 
of pigment, and denominated the parallel strice of Retzius, are seen on a section of 
the enamel. Their exact significance is uncertain. 
Numerous minute interstices intervene between the enamel-fibres near their den- 
tinal surface-a provision calculated to allow of the permeation of fluids from the 
dentinal tubule into the substance of the enamel. The enamel-rods consist of solid 
hexagonal or four-sided prisms connected by their surfaces and ends and filled with 
calcareous matter. If the latter be removed by weak acid from newly-formed or 
growing enamel, it will be found to present a network of delicate prismatic cells of 
animal matter. It is a disputed point whether the dentinal fibres penetrate a cer- 
tain distance between the rods of the enamel or no. No nutritive canals exist in 
the enamel. 
Chemical Composition.-According to Bibra, enamel consists of 96.5 per cent, 
of earthy matter and 3.5 per cent, of animal matter. The earthy matter consists of 
phosphate of lime, with traces of fluoride of calcium, carbonate of lime, phosphate 
of magnesia, and other salts. 
The cortical substance, or cement (crusta petrosa), is disposed as a thin layer 
on the roots of the teeth from the termination of the enamel as far as the apex of 
the fang, where it is usually very thick. In structure and chemical composition it 
resembles bone. It contains, sparingly, the lacunae and canaliculi which characterize 
true bone; the lacunae placed near the surface have the canaliculi radiating from the 
side of the lacunae toward the periodontal membrane, and those more deeply placed 
join with the adjacent dental tubuli. In the thicker portions of the crusta petrosa 
the lamellae and Haversian canals peculiar to bone are also found. As age advances 846 
ORGANS OF DIGESTION. 
♦ 
the cement increases in thickness, and gives rise to those bony growths, or exostoses, 
so common in the teeth of the aged; the pulp-cavity becomes also partially filled up 
by a hard substance intermediate in structure between dentine and bone (psteo-den- 
tine, Owen ; secondary dentine, Tomes). It appears to be formed by a slow conver- 
sion of the dental pulp, which shrinks, or even disappears. 
Development of the Teeth. 
In describing the development of the teeth we have first to consider the mode 
of formation of the temporary or milk teeth, and then that of the permanent series. 
Development of the Temporary Teeth.-The development of these teeth in 
the foetus begins at a very early period. About the seventh week the margin of 
the jaw presents a slight longitudinal depression or groove with rounded borders. 
This is termed the primitive dental groove of Goodsir, and is caused by an involu- 
tion of the epithelium of the oral cavity into the subjacent connective tissue. The 
projecting borders of the groove are called the dental ridges. The groove consists, 
therefore, superficially, of a collection of epithelial cells, beneath which is a gelat- 
inous connective tissue, which is taken to represent the corium and connective tissue 
of the mucous membrane, and deeper than this is the ossifying substance of the jaw. 
The essential structures of the teeth are derived from these two elements-the 
enamel from the epithelium which covers the surface of the dental groove, the 
dentine and crusta petrosa from the deeper structures. 
First, as to the enamel. The primitive dental groove increases in size and 
becomes filled up and covered in by the epithelium, which becomes greatly increased 
in quantity, so that the groove is only indicated by a shallow superficial furrow. As 
the dental ridges-that is to say, the sides of the groove-rise up, the epithelial 
mass, which is named the enamel-germ, seems to pass deeper and deeper into the 
substance of the jaw, and at lasts meets with the papilla, presently to be described. 
The lower part of this mass of epithelial cells-that is, the part farthest from the 
margin of the jaw-spreads out in all directions, and the epithelial cells here 
increase in number. The mass thus assumes a flask shape, which is connected by 
a narrow neck, formed by the dental ridges, with the epithelial lining of the mouth. 
It may now be compared to a tubular gland, consisting of a dilated extremity filled 
with epithelium and opening by a narrow duct, also filled with epithelium, on the 
margin of the jaw. This narrow, constricted portion is called the neck of the enamel- 
organ, and is of importance as being the part from which the enamel-organ of the 
future permanent tooth is derived. The lower expanded portion of the mass of 
epithelial cells, the body of the flask, now inclines outward, so as to form an angle 
with the neck or more superficial part. 
In the soft connective tissue beneath this mass of epithelial cells a small papilla 
arises by an increased development and growth of the corpuscles of the part. The 
first appearance of this is the formation, just below the enamel-germ, of a dark semi- 
lunar area, which appears to embrace the bottom of the dental groove. From the 
centre of the concavity of this a ridge-subsequently differentiated into papillae- 
corresponding to the different teeth springs up. It grows upward, becomes vascular, 
and comes in contact with the epithelial cells of the enamel-germ, and is received 
into a dimple on its under surface. By its continued growth it pushes its way up 
into the enamel-germ, which becomes folded over it like a hood or cap. We have, 
then, at this stage, a vascular papilla which has already begun to assume somewhat 
the shape of the crown of the future tooth, surmounted by a sort of dome or cap of 
epithelial cells, which were originally the cells contained in the lower or expanded 
part of the flask-shaped primitive dental groove (Fig. 559). These cells now undergo 
a differentiation into three classes or varieties. Those which are in contact with 
the papilla, and which are continuous through the neck of the enamel-germ with 
the deepest layer of cells of the oral epithelium, become elongated, and form a layer 
of well-marked and regular columnar epithelium coating the papilla. These are 
named the internal enamel epithelium. The outer layer of cells of the enamel- THE TEETH. 
847 
germ, which are in contact with the inner surface of the dentinal sac, presently to 
be described, are much shorter, cubical in form, and are named the external enamel 
epithelium. All the intermediate round cells of the enamel-germ between these two 
layers undergo a peculiar change. They become stellate in shape, and their pro- 
cesses unite to form a network which resembles gelatinous connective tissue. 
While these changes have been going on the two horns of the semilunar mass, 
before spoken of as embracing the enamel-germ, and from which the papilla was 
derived, extend upward, surrounding the rudimentary tooth and becoming converted 
into a vascular membrane, constituting a sac-the dentinal sac-which encloses the 
Fig. 560. 
Fig. 559. 
Dental Sac of a Human Embryo at an Advanced 
Stage of Development, partly diagrammatic : 
a, wall of the sac, formed of connective tissue, 
with its outer stratum, a1, and its inner, a2 ; b, 
enamel-organ, with its papillary and parietal 
layer of cells; c, d, the enamel-membrane and 
enamel-prisms; e, dentine cells; f, dental 
germ and capillaries; g, i, transition of the 
wall of the follicle into the tissue of the den- 
tal germ. 
Vertical Section of the Inferior Maxilla of an Early 
Human Foetus (magnified 25 diams.): 1, dental 
groove; 2, remains of the enamel-germ; 3, enamel- 
organ presenting externally epithelium, as also 
where it forms the enamel-germ of the papillae of 
the dental sacculus; 4, secondary enamel-germ- 
rudiment of the permanent tooth; 5, dental germ; 
6, lower jaw; 7, Meckel's cartilage. 
tooth. As they grow upward the two horns approach each other, and, penetrating 
the dental ridges or lips of the primitive groove, they cause the neck of the enamel- 
organ to atrophy and disappear, so that all communication between the enamel-germ 
and the superficial epithelium is cut off. 
We have now a vascular papilla surmounted by an inverted cap or capsule of 
epithelial cells, the whole being surrounded by a membranous sac. The cap or cap- 
sule consists of an internal layer of cells-the internal enamel epithelium-in con- 
tact with the papilla; of an external layer of cells-the external enamel epithelium- 
lining the interior of the dentinal capsule; and of an intermediate mass of stellate 
cells with anastomosing processes (Fig. 560). The enamel is formed exclusively from 
the internal enamel epithelium, the columnar cells of which undergo direct calcifica- 
tion and become elongated into the hexagonal rods of the enamel. The intermediate 
cells atrophy and disappear, so that the calcified internal enamel epithelium and 
the external enamel epithelium come into close apposition, and the cells of this lat- 
ter layer form a distinct membrane, named the cuticula dentis or Nasmyth's mem- 
brane, which long remains perceptible, and after the tooth has emerged from the 
gums forms a horny layer which may be separated from the calcified mass below by 
the action of strong acids. It is marked by the hexagonal impressions of the 
enamel-prisms, and when stained by nitrate of silver shows the characteristic- 
appearance of epithelium. It soon, however, wears away from the surface of the 
tooth. 
Formation of the Dentine.-While these changes are taking place in the epithe- 848 
ORGANS OF DIGESTION. 
lium to form the enamel, contemporaneous changes are occurring in the blastema or 
corium which result in the formation of the dentine and cement. As before stated, 
the first germ of the dentine consists in the formation of a dark semilunar area 
around the bottom of the dental groove. From the middle of this a projection 
springs up, at first in the form of a ridge, which extends along the whole length 
of the jaw. The ridge becomes subsequently divided into papillae, corresponding 
in number to the teeth, by the atrophy of the intervening parts. The papillae grow 
upward into the enamel-organ, and become coated by it and enclosed in a vascular 
connective tissue, the dentinal sac, in the manner above described. They then con- 
stitute the formative pulp from which the dentine and permanent pulp are derived. 
Each papilla consists of rounded cells and is very vascular, and soon begins to 
assume the shape of the tooth which is to be developed from it. The next step is 
the formation of the odontoblasts, which have a relation to the development of the 
teeth similar to that of the osteoblasts in the formation of bone. They are formed 
first from the cells of the periphery of the papilla, which become enlarged and of 
an elongated form and provided with numerous processes. These processes as they 
grow become calcified externally, the calcified portion forming the walls of the den- 
tinal tubules, and the uncalcified axial portion the dentinal fibres (Tomes's fibres) 
which are contained within the tubules. In addition to this the lateral processes 
from the odontoblasts form the branches of anastomosis whereby the dentinal canals 
communicate. In this way the peripheral layer of the papilla becomes coated with 
a solid shell of dentine, on the inner surface of which a second layer of odontoblast 
is arranged, and in its turn calcifies; and thus the process goes on through the entire 
thickness of the dentine, the processes of one odontoblast being directly continuous 
with those in succeeding layers, so that each dental fibre must be regarded as formed 
by several continuous odontoblasts. The central part of the papilla does not undergo 
calcification; its cells proliferate, nerve-fibres are developed in it, and it remains 
persistent as the pulp of the tooth. The cement is formed from the wall of the 
dentinal sac, which is developed from the two horns of the semilunar mass at the 
bottom of the dental groove from which the papilla originally sprung. So that the 
dentine and cement may be said to originate from analogous structures. In this 
membranous sac ossification goes on in a manner identical with the intramembra- 
nous ossification of bone, and the cement formed is merely ordinary bone, contain- 
ing canaliculi and lacunae. 
The germs of the milk teeth make their appearance in the following order: At 
the seventh week the germ of the first molar of the upper jaw appears; at the 
■eighth week, that for the canine tooth is developed; the two incisor papillae appear 
about the ninth week (the central preceding the lateral); lastly, the second molar 
papilla is seen at the tenth week behind the anterior molar. The teeth of the 
lower jaw appear rather later, the first molar papilla being only just visible at the 
seventh week, and the second molar papilla not being developed before the elev- 
enth week. 
Development of the Permanent Teeth.-The permanent teeth, as regards 
their development, may be divided into two sets: (1) those which replace the tempo- 
rary teeth, and, like them, are ten in number: these are the successional permanent 
teeth ; and (2) those which have no temporary predecessors, but are superadded at 
the back of the dental series. These are three in number on either side in either 
jaw, and are termed the super added permanent teeth. They are the three molars 
of the permanent set, the molars of the temporary set being replaced by the pre- 
molars or bicuspids of the permanent set. The development of the successional 
permanent teeth-the ten anterior ones in either jaw-will be first considered. In 
the neck of the enamel-organ of the temporary tooth, prior to the meeting of the 
two dental ridges and the obliteration of this portion of the primitive dental groove, 
an indentation of the epithelium takes place in the layer of cells forming the poste- 
rior wall of the neck of the sac. This forms a groove or indentation similar to the 
groove in the oral epithelium of the margin of the jaw which formed the primitive 
dental groove, and from its resemblance is termed by Goodsir the secondary dental THE TEETH. 
849 
groove. These grooves or depressions are ten in number in each jaw, and are formed 
successively from before backward. They become filled with epithelial cells, and 
recede into the substance of the gum behind the germs of the temporary teeth. 
They constitute the enamel-germs of the permanent teeth. As they recede they 
become flask-shaped from an expansion of their distal extremity, and finally meet a 
papilla which has been formed in the corium, just in the same manner as was the 
case in the temporary teeth. The apex of the papilla indentates the enamel-germ, 
which encloses it, and, forming a cap for it, undergoes analogous changes to those 
described in the development of the milk teeth, and becomes converted into the 
enamel, whilst the papilla forms the dentine of the permanent tooth. In its devel- 
opment it becomes enclosed in a dental sac which adheres to the back of the sac of 
the temporary tooth. The sac of each permanent tooth remains connected with the 
fibrous tissue of the gum by a slender band or gub'ernaculum, which passes to the 
margin of the jaw behind the corresponding milk tooth. 
The superadded permanent teeth-three on each side in each jaw-arise from 
successive extensions backward of the back part of the enamel-germ of the imme- 
diately preceding tooth. During the fourth month that portion of the enamel-germ 
of the last temporary molar tooth which lies behind the tooth, and which has 
remained unobliterated, is prolonged backward and forms the enamel-germ of the 
first permanent molar into which a papilla projects. From this tooth in a similar 
manner, about the seventh month after birth, the second molar is formed; and 
about the third year the third molar is formed by an extension backward of the 
enamel-germ of the second molar. 
Eruption.-When the calcification of the different tissues of the tooth is suf- 
ficiently advanced to enable it to bear the pressure to which it will be afterward 
subjected, its eruption takes place, the tooth making its way through the gum. 
The gum is absorbed by the pressure of the crown of the tooth against it, which is 
itself pressed up by the increasing size of the fang. At the same time the septa 
between the dental sacs, at first fibrous in structure, ossify and constitute the alve- 
[Fig. 561. 
The above figure shows the Denture of a Child about Seven Years Old. The " sixth-year molars" have already 
appeared. The other permanent teeth are seen partially developed and concealed in the two jaw-bones 
(Litch).] 
oli; these firmly embrace the necks of the teeth and afford them a solid basis of 
support. 
The eruption of the temporary teeth commences at the seventh month, and is 
complete about the end of the second year, those of the lower jaw preceding the 
upper. 850 
ORGANS OF DIGESTION. 
The periods for the eruption of the temporary set are- 
7th month, central incisors. 
7th to 10th month, lateral incisors. 
12th to 14th month, anterior molars. 
14th to 20th month, canine. 
18th to 36th month, posterior molars. 
Calcification of the permanent teeth commences a little before birth, and proceeds 
in the following order in the upper jaw, in the lowei* jaw a little earlier: First molar, 
fifth or sixth month; the central incisor a little later; lateral incisors and canine about 
the eighth or ninth month ; the bicuspids at the second year; second molar fifth or 
sixth year; wisdom tooth about the twelfth year. 
Previous to the permanent teeth penetrating the gum the bony partitions which 
separate their sacs from the deciduous teeth are absorbed, the fangs of the tempo- 
rary teeth disappear by absorption through the agency of particular multinucleated 
cells called odontoclasts which are developed at the time in the neighborhood of the 
fang, and the permanent teeth become placed under the loose crowns of the decid- 
uous teeth; the latter finally become detached, and the permanent teeth take their 
place in the mouth. 
The eruption of the permanent teeth takes place at the following periods, the 
teeth of the lower j aw preceding those of the upper by a short interval: 
6| years, first molars. 
7th year, two middle incisors. 
8th year, two lateral incisors. 
9th year, first bicuspid. 
10th year, second bicuspid. 
11th to 12th year, canine. 
12th to 13th year, second molars. 
17th to 21st year, wisdom teeth. 
[As they are very liable to decay unless they receive proper attention and care, 
it is important that the student should notice that the first permanent molars (gen- 
erally called the " sixth-year molars ") make their eruption before the incisors.] 
THE PALATE. 
The Palate [Fig. 552, p. 840] forms the roof of the mouth: it consists of two 
portions, the hard palate in front, the soft palate behind. [The line of junction of 
the two can be easily felt, and also is marked to the eye by a different color. The 
soft palate makes nearly half of the roof of the mouth.] 
The hard palate is bounded in front and at the sides by the alveolar arches 
and gums; behind, it is continuous with the soft palate. It is covered by a dense 
structure formed by the periosteum and mucous membrane of the mouth, which are 
intimately adherent together. Along the middle line is a linear ridge or raph6, 
which terminates anteriorly in a small papilla corresponding with the inferior open- 
ing of the anterior palatine fossa. This papilla receives filaments from the naso- 
palatine and anterior palatine nerves. On either side and in front of the raphd 
the mucous membrane is thick, pale in color, and corrugated; behind, it is thin, 
smooth, and of a deeper color: it is covered with squamous epithelium, and fur- 
nished with numerous glands (palatal glands) which lie between the mucous mem- 
brane and the surface of the bone. 
The soft palate (velum pendulum palati) is a movable fold suspended from the 
posterior border of the hard palate and forming an incomplete septum between the 
mouth and pharynx. It consists of a fold of mucous membrane enclosing muscular 
fibres, an aponeurosis, vessels, nerves, adenoid tissue, and mucous glands. When 
occupying its usual position (i. e. relaxed and pendent), its anterior surface is con- 
cave, continuous with the roof of the mouth, and marked by a median ridge or 
raphd, which indicates its original separation into two lateral halves. Its posterior 
surface is convex, and continuous with the mucous membrane covering the floor of 
the posterior nares. Its upper border is attached to the posterior margin of the 
hard palate, and its sides are blended with the pharynx. Its lower border is free. 
Hangimz from the middle of its lower border is a small conical-shaped pendulous THE PALATE. 
851 
process, the uvula, and arching outward and downward from the base of the uvula 
on each side are two curved folds of mucous membrane containing muscular fibres, 
called the arches or pillars of the soft palate. 
The anterior pillars run downward, outward, and forward to the sides of the base 
of the tongue, and are formed by the projection of the Palato-glossi muscles, covered 
by mucous membrane. 
The posterior pillars are nearer to each other and larger than the anterior; they 
run downward, outward, and backward to the sides of the pharynx, and are formed 
by the projection of the Palato-pharyngei muscles, covered by mucous 'membrane. 
The anterior and posterior pillars are separated below by a triangular- interval in 
which the tonsil is lodged. 
The space left between the arches of the palate on the two sides is called the 
isthmus of the fauces. It is bounded above by the free margin of the palate, 
below by the tongue, and on each side by the pillars of the soft palate and the 
tonsil. 
The mucous membrane of the soft palate is thin, and covered with squamous epi- 
thelium on both surfaces, excepting near the orifice of the Eustachian tube, where it 
is columnar and ciliated.1 Beneath the mucous membrane, on the oral surface of the 
soft palate, is a considerable amount of adenoid tissue. The palatine glands form a 
continuous layer on its posterior surface and around the uvula. 
The aponeurosis of the soft palate is a thin but firm fibrous layer attached above 
to the hard palate and becoming thinner toward the free margin of the velum. It is 
blended with the aponeurotic tendon of the Tensor palati muscle. 
The muscles of the soft palate are five on each side-the Levator palati, Tensor 
palati, Palato-glossus, Palato-pharyngeus, and Azygos uvulae [or Levator uvulae] (see 
p. 394). The following is the relative position of these structures in a dissection of the 
soft palate from the posterior or nasal to the anterior or oral surface : Immediately 
beneath the nasal mucous membrane is a thin stratum of muscular fibres, the poste- 
rior fasciculus of the Palato-pharyngeus muscle joining with its fellow of the oppo- 
site side in the middle line. Beneath this is the Azygos uvulae, consisting of two 
rounded fleshy fasciculi placed side by side in the median line of the soft palate. 
Next comes the aponeurosis of the Levator palati joining with the muscle of the 
opposite side in the middle line. Fourthly, the anterior fasciculus of the Palato- 
pharyngeus, thicker than the posterior and separating the Levator palati from the 
next muscle, the Tensor palati. This muscle terminates in a tendon which, after 
winding round the hamular process, expands into a broad aponeurosis in the soft 
palate anterior to the other muscles which have been enumerated. Finally, we 
have a thin muscular stratum, the Palato-glossus muscle, placed in front of the apo- 
neurosis of the Tensor palati, and separated from the oral mucous membrane by 
adenoid tissue. 
The Tonsils (amygdalaf are two glandular organs situated one on each side of 
the fauces, between the anterior and posterior pillars of the soft palate. They are 
of a rounded form, and vary considerably in size in different individuals. Exter- 
nally the tonsil is in relation with the inner surface of the Superior constrictor, 
which separates it from the internal carotid and ascending pharyngeal arteries. It 
corresponds to the angle of the lower jaw. Its inner surface presents from twelve 
to fifteen orifices leading into small recesses, from which numerous follicles branch 
out into the substance of the gland. These follicles are lined by a continuation of 
the mucous membrane of the pharynx, covered with epithelium; around each folli- 
cle is a layer of closed capsules imbedded in the submucous tissue. These capsules 
are analogous to those of Peyer's glands, consisting of adenoid tissue. No openings 
from the capsules into the follicles can be recognized. They contain a thick grayish 
secretion. 
The arteries supplying the tonsil are the dorsalis linguae from the lingual, the 
ascending palatine and tonsillar from the facial, the ascending pharyngeal from the 
1 According to Klein, the mucous membrane on the nasal surface of the soft palate is in the foetus 
covered throughout by columnar ciliated epithelium. 852 
ORGANS OF DIGESTION. 
external carotid, the descending palatine branch of the internal maxillary, and a 
twig from the small meningeal. 
The veins terminate in the tonsillar plexus, on the outer side of the tonsil. 
The nerves are derived from Meckel's ganglion and from the glosso-pharyngeal. 
THE SALIVARY GLANDS (Fig. 562). 
The principal salivary glands communicating with the mouth and pouring their 
secretion into its cavity are the parotid, submaxillary, and sublingual. 
The Parotid Gland, so called from being placed near the ear (napd, near; out;, 
Fig. 562. 
The Salivary Glands. 
(broi;, the ear), the largest of the three salivary glands, varying in weight from half 
an ounce to an ounce. It lies upon the side of the face immediately below and in 
front of the external ear. It is limited above by the zygoma; below by the angle 
of the jaw and by a line drawn between it and the mastoid process; anteriorly it 
extends to a variable extent over the Masseter muscle; posteriorly it is bounded by 
the external meatus, the mastoid process, and the Sterno-mastoid and Digastric mus- 
cles, slightly overlapping the former. 
Its anterior surface is grooved to embrace the posterior margin of the ramus of 
the lower jaw, and advances forward beneath the ramus between the two Pterygoid 
muscles. Its outer surface, slightly lobulated, is covered by the integument and 
fascia, and has one or two lymphatic glands resting on it. Its inner surface extends 
deeply into the neck by means of two large processes, one of which dips behind the 
styloid process and projects beneath the mastoid process and the Sterno-mastoid mus- 
cle; the other is situated in front of the styloid process, and passes into the back 
part of the glenoid fossa behind the articulation of the lower jaw. Imbedded in its 
substance is the external carotid artery, which ascends behind the ramus of the jaw; 
the posterior auricular artery emerges from the gland behind, the temporal artery THE SALIVARY GLANDS. 
853 
above, the transverse facial in front, and the internal maxillary winds through it 
inward, behind the neck of the jaw. Superficial to the external carotid is the trunk 
formed by the union of the temporal and internal maxillary veins; a branch con- 
necting this trunk with the internal jugular also passes through the gland. It is 
also traversed, from before backward, by the facial nerve and its branches, which 
emerge at its anterior border; branches of the great auricular nerve pierce the gland 
to join the facial, and the auriculo-temporal branch of the inferior maxillary nerve 
lies above the upper part of the gland. The internal carotid artery and internal 
jugular vein lie close to its deep surface. 
The Duct of the Parotid Gland (Stenson's [more commonly, but less correctly, 
called " Steno's "]) is about two inches and a half in length. Its canal is about the 
size of a crow-quill. It opens upon the inner surface of the cheek by a small orifice 
opposite the second molar tooth of the upper jaw; and from this orifice it may be 
traced obliquely for a short distance beneath the mucous membrane, and thence 
through the substance of the Buccinator muscle and across the Masseter to the 
anterior border of the gland, in the substance of which it commences by numerous 
branches. The direction of the duct corresponds to a line drawn across the face 
about a finger's breadth below the zygoma, from the lower part of the concha to 
midway between the free margin of the upper lip and the ala of the nose. While 
crossing the Masseter it receives the duct of a small detached portion of the gland, 
socia parotidis,\v}\ic\\ occasionally exists as a separate lobe just beneath the zygo- 
matic arch. The parotid duct is dense, of considerable thickness; it consists of an 
external or fibrous coat of considerable density containing contractile fibres, and 
of an internal or mucous coat lined with short columnar epithelium. 
Vessels and Nerves.-The arteries supplying the parotid gland are derived 
from the external carotid and from the branches given off by that vessel in or near 
its substance. The veins empty themselves into the External jugular through some 
of its tributaries. The lymphatics terminate in the superficial and deep cervical 
glands, passing in their course through two or three lymphatic glands placed on the 
surface and in the substance of the parotid. The nerves are derived from the caro- 
tid plexus of the sympathetic, the facial, and the superficial temporal branches of 
the auriculo-temporal and great auricular nerves. 
The Submaxillary Gland, is situated below' the jaw. in the anterior part of the 
submaxillary triangle of the neck. It is irregular in form and weighs about two 
drachms. It is covered by the 
integument, Platysma, deep cer- 
vical fascia, and the body of the 
lower jaw, corresponding to a de- 
pression on the inner surface of 
that bone, and lies upon the Mylo- 
hyoid, Hyo-glossus, and Stylo- 
glossus muscles, a portion of the 
gland passing beneath the poste- 
rior border of the Mylo-hyoid. 
In front of it is the anterior belly 
of the Digastric; behind, it is 
separated from the parotid gland 
by the stylo-maxillary ligament, 
and from the sublingual gland in 
front by the Mylo-hyoid muscle. 
The facial artery lies imbedded 
in a groove in its posterior and 
upper border. 
The Duct of the Submaxillary Gland (Wharton s'} is about two inches in 
length, and its walls are much thinner than those of the parotid duct. It opens by 
a narrow' orifice on the summit of a small papilla at the side of the fraenum linguae. 
Traced from thence, it is found to pass between the sublingual gland and the Genio- 
Fig. 563. 
A Highly-magnified Section of the Submaxillary Gland of the 
Dog, stained with carmine (Kdlliker): a, cross-section of small 
salivary duet; b, an alveolus containing salivary cells; c, cres- 
cent of Gianuzzi. 854 
ORGANS OF DIGESTION. 
hyo-glossus muscle, then backward and outward between the Mylo-hyoid and rhe 
Hyo-glossus and Genio-hyo-glossus muscles, to the deep portion of the gland, where 
it commences by numerous branches. On the Hyo-glossus muscle it lies between 
the gustatory and hypoglossal nerves, but at the anterior border of the muscle it 
crosses beneath the gustatory nerve, and is then placed above it. 
Vessels and Nerves.-The arteries supplying the submaxillary gland are 
branches of the facial and lingual. Its veins follow the course of the arteries. 
The nerves are derived from the submaxillary ganglion, through which it receives 
filaments from the chorda tympani of the facial and gustatory branch of the infe- 
rior maxillary, from the mylo-hyoid branch of the inferior dental, and from the 
sympathetic. 
The Subling-ual Gland is the smallest of the salivary glands. It is situated 
beneath the mucous membrane of the floor of the mouth, at the side of the frse- 
num linguae, in contact with the inner surface of the lower jaw, close to the sym- 
physis. It is narrow, flattened, in shape somewhat like an almond, and weighs 
about a drachm. It is in relation above with the mucous membrane; below with 
the Mylo-hyoid muscle; in front with the depression on the side of the symphysis 
of the lower jaw and with its fellow of the opposite side; behind with the deep part 
of the submaxillary gland; and internally with the Genio-hyo-glossus, from which 
it is separated by the lingual nerve and Wharton's duct. Its excretory ducts (cZucts 
of Rivini\ from eight to twenty in number, open separately into the mouth, on the 
elevated crest of the mucous membrane caused by the projection of the gland on 
either side of the fraenum linguae. One or more join to form a tube which opens 
into the Whartonian duct; this is called the duct of Bartholin. 
Vessels and Nerves.-The sublingual gland is supplied with blood from the 
sublingual and submental arteries. Its nerves are derived from the gustatory. 
Structure.-The salivary are compound racemose glands, consisting of numer- 
ous lobes which are made up of smaller lobules connected together by dense areolar 
tissue, vessels, and ducts. Each lobule consists of the ramifications of a single duct, 
"branching frequently in a tree-like manner," the branches terminating in dilated 
ends or alveoli on which the capillaries are distributed. These alveoli, however, as 
Pfliiger points out, are not necessarily spherical, though sometimes they assume that 
form; sometimes they are perfectly cylindrical, and very often they are mutually 
compressed. The alveoli are enclosed by a basement membrane which is continuous 
with the membrana propria of the duct. It presents a peculiar reticulated structure, 
having the appearance of a basket with open meshes, and consisting of a network of 
branched and flattened nucleated cells. 
The alveoli of the salivary glands are of two kinds, which differ both in the 
appearance of their secreting cells, in their size, and in the nature of their secre- 
tion. The one variety secretes a ropy fluid which contains mucin, and have there- 
fore been named the mucous, whilst the other secretes a thinner and more watery 
fluid which contains serum-albumen, and have been named serous or albuminous. 
The sublingual gland may be regarded as an example of the former variety, the 
parotid of the latter. The submaxillary is of the mixed variety, containing both 
mucous and serous alveoli, the latter, however, preponderating. 
Both alveoli are lined by cells, and it is by the character of these cells that the 
nature of the gland is chiefly to be determined. In addition, however, the alveoli 
of the serous glands are smaller than those of the mucous ones. 
The cells in the mucous alveoli are spheroidal in shape, glassy, transparent, 
and dimly striated in appearance. The nucleus is usually situated in the part of 
the cell which is next the basement membrane, against which it is sometimes flat- 
tened. The most remarkable peculiarity presented by these cells is, that they give 
off an extremely fine process, which is curved in a direction parallel to the surface 
of the alveolus, lies in contact with the membrana propria, and overlaps the processes 
of neighboring cells. The cells contain a quantity of mucin, to which their clear, 
transparent appearance is due. 
Here and there in the alveoli are seen peculiar half-moon-shaped bodies lying THE SALIVARY GLANDS. 
855 
between the cells and the membrana propria of-the alveolus. They are termed the 
crescents of Gianuzzi or the demilunes of Heidenhain (Fig. 563), and are regarded 
by Pfliiger as due to post-mortem change; but by most other later observers they 
Fig. 564. 
Illustrating Pfliiger's Views of the Termination of the Nerves in the Alveolar Cells (from Stricker's Handbook'). 
A, direct passage of nerve into a salivary cell. 
B, by the medium of a multipolar ganglion-cell, g. 
are believed to be composed of polyhedral granular cells, which Heidenhain regards 
as young epithelial cells destined to supply the place of those salivary cells which 
have undergone disintegration. This view, however, is not accepted by Klein. 
Serous Alveoli.-In the serous alveoli the cells almost completely fill the cav- 
ity, so that there is hardly any lumen perceptible. Instead of presenting the clear 
transparent appearance of the cells of the mucous alveoli, they present a granular 
appearance, due to distinct granules of an albu- 
minous nature imbedded in a closely-reticulated 
protoplasm. The ducts which originate out of 
the alveoli are lined at their commencement by 
epithelium which differs little from the pavement 
type. As the ducts enlarge the epithelial cells 
change to the columnar type, and they are de- 
scribed by Pfluger as attached to the basement 
membrane by a brush of fine hair-like processes, 
which he believes to be continuous with the 
nerve-fibres. Other anatomists regard these 
cells as merely striated on their deep surface. 
The ducts do not spring only from the alveoli, 
for between the cells of the alveolus itself a fine 
branching network is found, which is either a 
lymphoid tissue continuous with the sheath of 
the duct or a system of branching tubes by 
which the ducts commence between the sali- 
vary cells (Fig. 565), as the biliary ducts are 
said to commence between the hepatic cells. The ducts have also diverticular pas- 
sages lined with columnar epithelium; and it seems that the secretion goes on in 
these diverticula and in the wider portions of the ducts where the columnar epithe- 
lium exists, as well as in the alveoli. The lobules of the salivary glands are richly 
supplied with blood-vessels, which form a dense network in the interalveolar spaces. 
Fine plexuses of nerves are also formed in the interlobular tissue. Pfluger describes 
the nerves as being directly continuous with the salivary cells of the alveolus, the 
nerve sometimes passing through a ganglion-cell just before joining the alveolus 
(Fig. 564, a and b). 
In the submaxillary and sublingual glands the lobes are larger and more looselj 
united than in the parotid. 
Fig. 565. 
An Alveolus of a Compound Racemose Gland, 
injected from the Excretory Duct (highly 
magnified). Hardly anything but the dark 
injecting fluid is shown; the alveolar cells 
and nuclei are only faintly indicated; those 
of the duct are not represented at all. The 
injection is seen filling the central cavity 
of the alveolus, and passing from this in 
fine channels (represented by black reticu- 
lating lines) between and around the cells 
(after Saviotti). 856 
ORGANS OF DIGESTION. 
Mucous Glands.-Besides the salivary glands proper, numerous other glands 
are found in the mouth. They appear to secrete mucus only, which serves to keep 
the mouth moist during the intervals of the salivary secretion, and which is mixed 
with that secretion in swallowing. Many of these glands are found at the posterior 
part of the dorsum of the tongue, behind the circumvallate papillae, and also along 
its margins as far forward as the apex.1 Others lie around and in the tonsil between 
its crypts, and a large number in the soft palate. These glands are of the ordinary 
compound racemose type. 
THE PHARYNX. 
The Pharynx is that part of the alimentary canal which is placed behind the 
nose, mouth, and larynx. It is a musculo-membranous sac, somewhat conical in 
form, with the base upward and the apex downward, extending from the under sur- 
face of the skull to the cricoid cartilage in front and the intervertebral disk between 
the fifth and sixth cervical vertebrae behind. [Its upper and lower portions are 
often and conveniently named the naso-pharynx and the oro-pharynx.] 
The pharynx is about four inches and a half in length, and broader in the trans- 
verse than in the antero-posterior diameter. Its greatest breadth is opposite the 
cornua of the hyoid bone, its narrowest point at its termination in the oesophagus. 
It is limited above by the body of the sphenoid and basilar process of the occipital 
bone; below it is continuous with the oesophagus; posteriorly it is connected by 
loose areolar tissue with the cervical portion of the vertebral column and the Longi 
colli and Recti capitis antici muscles; anteriorly it is incomplete, and is attached 
in succession to the internal pterygoid plate, the pterygo-maxillary ligament, the 
lower jaw, the tongue, hyoid bone, and larynx; laterally it is connected to the 
styloid processes and their muscles, and is in contact with the common and internal 
carotid arteries, the internal jugular veins, and the glosso-pharyngeal, pneumogas- 
tric, hypoglossal, and sympathetic nerves, and above with a small part of the Inter- 
nal pterygoid muscles. 
It has seven openings communicating with it: the two posterior nares, the two 
Eustachian tubes, the mouth, larynx, and oesophagus. 
The posterior nares are the two large apertures situated at the upper part of the 
anterior wall of the pharynx. 
The two Eustachian tubes open one at each side of the upper part of the pharynx, 
at the back part of the inferior meatus. 
Below the nasal fossae are the posterior surface of the soft palate and uvula, the 
large aperture of the mouth, the base of the tongue, the epiglottis, and the cordiform 
opening of the larynx. 
The oesophageal opening is the lower contracted portion of the pharynx. 
Structure.-The pharynx is composed of three coats-mucous, fibrous, and 
muscular. 
The fibrous coat is situated between the mucous and muscular layers, and is 
called the pharyngeal aponeurosis. It is thick above, where the muscular fibres 
are wanting, and is firmly connected to the basilar process of the occipital and 
petrous portion of the temporal bones. As it descends it diminishes in thickness 
and is gradually lost. It is strengthened posteriorly by a strong fibrous band, 
which is attached above to the pharyngeal spine on the under surface of the basilar 
portion of the occipital bone, and passes downward, forming a median raphd which 
gives attachment to the Constrictor muscles of the pharynx. 
The mucous coat is continuous with that lining the Eustachian tubes, the nares, 
the mouth, and the larynx. It is covered by columnar ciliated epithelium as low 
1 It has been recently shown by Ebner that many of these glands open into the trenches around 
the circumvallate papillae, and that their secretion is more watery than that of ordinary mucous 
glands. He supposes that they assist in the more rapid distribution of the substance to be tasted over 
the region where the special apparatus of the sense of taste is situated. THE (ESOPHAGUS. 
857 
down as on a level with the floor of the nares; below that point the epithelium is 
of the squamous variety. Beneath the mucous membrane are found racemose 
mucous glands; they are especially numerous at the upper part of the pharynx 
around the orifices of the Eustachian tubes. Throughout the pharynx are also 
numerous crypts or recesses, the walls of which are surrounded by lymphoid tissue 
similar to what is found in the tonsils. Across the back part of the pharyngeal 
cavity, between the two Eustachian tubes, a considerable mass of this tissue exists, 
and has been named the pharyngeal tonsil. 
The muscular coat has been already described (p. 392). 
THE CESOPHAGUS. 
The CEsophagus or Gullet is a muscular canal, about nine inches in length, 
extending from the pharynx to the stomach. It commences at the upper border 
of the cricoid cartilage, opposite the intervertebral disk between the fifth and sixth 
cervical vertebrae, descends along the front of the spine through the posterior medi- 
astinum, passes through the Diaphragm, and, entering the abdomen, terminates at 
the cardiac orifice of the stomach opposite the ninth dorsal vertebra. The general 
direction of the oesophagus is vertical, but it presents two or three slight curvatures 
in its course. At its commencement it is placed in the median line, but it inclines 
to the left side as far as the root of the neck, gradually passes to the middle line 
again, and finally again deviates to the left as it passes forward to the oesophageal 
opening of the Diaphragm. The oesophagus also presents an antero-posterior 
flexure corresponding to the curvature of the cervical and thoracic portions 
of the spine. It is the narrowest part of the alimentary canal, being most con- 
tracted at its commencement and at the point where it passes through the 
Diaphragm. 
Relations.-In the neck the oesophagus is in relation, in front, with the trachea, 
and at the lower part of the neck, where it projects to the left side, with the thyroid 
gland and thoracic duct; behind it rests upon the vertebral column and Longus colli 
muscle; on each side it is in relation with the common carotid artery (especially the 
left, as it inclines to that side) and part of the lateral lobes of the thyroid gland; 
the recurrent laryngeal nerves ascend between it and the trachea. 
In the thorax it is at first situated a little to the left of the median line; it then 
passes behind the left side of the transverse part of the aortic arch, and descends in 
the posterior mediastinum, along the right side of the aorta, nearly to the Dia- 
phragm, where it passes in front and a little to the left of the artery previous to 
entering the abdomen. It is in relation in front with the trachea, the arch of the 
aorta, left carotid, and left subclavian arteries, the left bronchus, and the posterior 
surface of the pericardium; behind it rests upon the vertebral column, the Longus 
colli, and the intercostal vessels, and below, near the Diaphragm, upon the front of 
the aorta; laterally it is covered by the pleurae: the vena azygos major lies on the 
right and the descending aorta on the left side. The pneumogastric nerves descend 
in close contact with it, the right nerve passing down behind and the left nerve in 
front of it. 
Surgical Anatomy.--The relations of the oesophagus are of considerable practical interest 
to the surgeon, as he is frequently required, in cases of stricture of this tube, to dilate the canal 
by a bougie, when it is of importance that the direction of the oesophagus and its relations to 
surrounding parts should be remembered. In cases of malignant disease of the oesophagus, 
where its tissues have become softened from infiltration of the morbid deposit, the greatest care 
is requisite in directing the bougie through the strictured part, as a false passage may easily be 
made, and the instrument may pass into the mediastinum or into one or the other pleural cavity, 
or even into the pericardium. 
The student should also remember that contraction of the oesophagus and consequent symp- 
toms of stricture are occasionally produced by an aneurism of some part of the aorta pressing 
upon this tube. In such a case the passage of a bougie could only hasten the fatal issue. 
It occasionally happens that a foreign body becomes impacted in the oesophagus which can 
neither be brought upward nor moved downward. When all ordinary means for its removal 858 
O/rGLlAA OF DIGESTION. 
have failed, excision is the only resource. This, of course, can only be performed when it is 
not very low down. If the foreign body is allowed to remain, extensive inflammation and ulcer- 
ation of the oesophagus may ensue. In one case the foreign body ultimately penetrated the 
intervertebral substance, and destroyed life by inflammation of the membranes and substance 
of the cord. 
The operation of oesophagotomy is thus performed: The patient being placed upon his back, 
with the head and shoulders slightly elevated, an incision about four inches in length should be 
made on the left side of the trachea, from the thyroid cartilage downward, dividing the skin 
and Platysma. The edges of the wound being separated, the Omo-hyoid muscle should, if 
necessary, be divided, and the fibres of the Sterno-hyoid and Sterno-thyroid muscles drawn 
inward; the sheath of the carotid vessels, being exposed, should be drawn outward and retained 
in that position by retractors : the oesophagus will then be exposed, and should be divided over 
the foreign body, which should then be removed. Great care is necessary to avoid wounding 
the thyroid vessels, the thyroid gland, and the laryngeal nerves. 
Structure.-The oesophagus has three coats-an external or muscular, a middle 
or areolar, and an internal or mucous coat. 
The muscular coat is composed of two planes of fibres of considerable thickness 
-an external longitudinal and an internal circular. 
The longitudinal fibres are arranged at the commencement of the tube in three 
fasciculi: one in front, which is attached to the vertical ridge on the posterior sur- 
face of the cricoid cartilage: and one at each side, which are continuous with the 
fibres of the Inferior constrictor: as they descend they blend together and form a 
uniform layer, which covers the outer surface of the tube. 
The circular fibres are continuous above with the Inferior constrictor; their 
direction is transverse at the upper and lower parts of the tube, but oblique in the 
central part.1 
The muscular fibres in the upper part of the oesophagus are of a red color, and 
consist chiefly of the striped variety; but belowT they consist entirely of the invol- 
untary muscular fibre. 
The areolar coat connects loosely the mucous and muscular coats. 
The mucous coat is thick, of a reddish color above and pale below. It is dis- 
posed in longitudinal folds, which disappear on distension of the tube. Its surface 
is studded with minute papillae, and it is covered throughout with a thick layer of 
stratified pavement epithelium. Beneath the mucous membrane, between it and 
the areolar coat, is a layer of longitudinally arranged non-striped muscular fibres. 
This is the muscularis mucosce. [See Fig. 576, m, p. 876.] At the commence- 
ment it is absent or only represented by a few scattered bundles; lower down it 
forms a considerable stratum. 
The oesophageal glands are numerous small compound racemose glands scattered 
throughout the tube; they are lodged in the submucous tissue, and open upon the 
surface by a long excretory duct. They are most numerous at the lower part of 
the tube, where they form a ring round the cardiac orifice. 
THE ABDOMEN. 
The Abdomen is the largest cavity in the body. It is of an oval form, the 
extremities of the oval being directed upward and downward; the upper one being 
formed by the under surface of the Diaphragm, the lower by the upper concave 
surface of the Levator ani. In order to facilitate description it is artificially 
divided into two parts-an upper and larger part, the abdomen proper, and a lowei 
and smaller part, the pelvis. These two cavities are not separated from each other, 
but the limit between them is marked by the brim of the true pelvis. The space 
is wider above than below, and measures more in the vertical than in the transverse 
diameter. 
Boundaries.-The abdomen proper is bounded in front and at the sides by 
1 Accessory slips of muscular fibres are described by Dr. Cunningham as passing between the 
oesophagus and the pleura where it covers the thoracic aorta (almost always), or the root of the left 
bronchus (usually), or the back of the pericardium, or corner of the mediastinum (more rarely), as 
well as other still more rare accessory fibres (Journal of Anat. and Phys., vol. x. p. 320). THE ABDOMEN. 
859 
the lower ribs, the abdominal muscles, and the venter ilii; behind by the vertebral 
column and the Psoas and Quadratus lumborum muscles ; above by the Diaphragm; 
below by the brim of the pelvis. The muscles forming the boundaries of the cavity 
are lined upon their inner surface by a layer of fascia, differently arranged accord- 
ing to the part to which it is attached. 
The abdomen contains the greater part of the alimentary canal, some of the 
accessory organs to digestion-viz. the liver, pancreas, and spleen-and the kid- 
neys and suprarenal capsules. Most of these structures, as well as the wall of the 
cavity in which they are contained, are covered by an extensive and complicated 
serous membrane, the peritoneum. 
The apertures found in the walls of the abdomen for the transmission of struc- 
tures to or from it are the umbilicus, for the transmission (in the foetus) of the 
umbilical vessels; the caval opening in the Diaphragm, for the transmission of the 
inferior vena cava; the aortic opening, for the passage of the aorta, vena azygos, 
and thoracic duct; and the oesophageal opening, for the oesophagus and pneumo- 
Fig. 566. 
The Regions of the Abdomen and their Contents (edge of costal cartilages in dotted outline) 
gastric nerves. Beloiv, there are two apertures on each side-one for the passage 
of the femoral vessels, and the other for the transmission of the spermatic cord in 
the male and the round ligament in the female. 
Regions.-For convenience of description of the viscera, as well as of reference 
to the morbid condition of the contained parts, the abdomen is artifically divided 
into nine regions. Thus, if two circular lines are drawn round the body, the one 
parallel with the cartilages of the ninth ribs and the other with the highest point of 
the crests of the ilia, the abdominal cavity is divided into three zones-an upper, a 
middle, and a lower. If two parallel lines are drawn from the cartilage of the eighth 860 
ORGANS OF DIGESTION. 
rib on each side down to the centre of Poupart's ligament, each of these zones is 
subdivided into three parts, a middle and two lateral. 
The middle region of the upper zone is called the epigastric (s>-rr, over; 
the stomach), and the two lateral regions, the right and left hypochondriac (unb, 
under; ybvdpot, the cartilages). The central region of the middle zone is the umbili- 
cal, and the two lateral regions the right and left lumbar. The middle region of the 
lower zone is the hypogastric or pubic region, and the lateral regions are the right 
and left inguinal or iliac. The viscera contained in these different regions are the 
following (Fig. 566): 
Right Hypochondriac. 
The right lobe of the liver 
and the gall-bladder, hepatic 
flexure of the colon, and part 
of the right kidney. 
Epigastric Region. 
The middle and pyloric end 
of the stomach, left lobe of the 
liver, and lobulus Spigelii, the 
pancreas, the duodenum, parts 
of the kidneys and the supra- 
renal capsules [aorta and 
branches, vena cava, semi- 
lunar ganglia, thoracic duct]. 
Left Hypochondriac. 
The splenic end of the stom 
ach, the spleen and extremity 
of the pancreas, the splenic 
flexure of the colon, and part 
of the left kidney. 
Right Lumbar. 
Ascending colon, part of 
the right kidney, and some 
convolutions of the small in- 
testines. 
Umbilical Region. 
The transverse colon, part 
of the great omentum and mes- 
entery, transverse part of the 
duodenum, and some convolu- 
tions of the jejunum and ileum, 
part of both kidneys [and the 
receptaculum chyli]. 
Left Lumbar. 
Descending colon, part of 
the omentum, part of the left 
kidney, and some convolutions 
of the small intestines. 
Right Inguinal (Iliac). 
The caecum, appendix caeci 
[ureter, spermatic vessels]. 
Hypogastric Region. 
Convolutions of the small 
intestines, the bladder in chil- 
dren, and in adults if dis- 
tended, and the uterus during 
pregnancy [often the caecum, 
appendix vermiformis, and 
sigmoid flexure of colon]. 
Left Inguinal (Iliac). 
Sigmoid flexure of the colon 
[ureter, spermatic vessels]. 
THE PERITONEUM. 
The peritoneum (neptretvsiv, to extend around) is a serous membrane [belonging 
really, as has been already explained (p. 86), to the lymphatic system], and par- 
tially invests all the viscera contained in the abdominal and pelvic cavities. In 
consequence of the number and different shapes of these viscera the reflections of 
the peritoneum, as it invests them, are exceedingly complex and difficult to under- 
stand. 
The peritoneum partially invests all the viscera contained in the abdominal and 
pelvic cavities, forming the visceral layer of the membrane ; it is then reflected upon 
the internal surface of the parietes of those cavities, forming the parietal layer. The 
free surface of the peritoneum is smooth, moist, and covered by a layer of flattened 
endothelial cells; its attached surface is rough, being connected to the viscera and 
inner surface of the parietes by means of areolar tissue called the subperitoneal 
areolar tissue. The parietal portion is loosely connected with the fascia lining the 
abdomen and pelvis, but more closely to the under surface of the Diaphragm and in 
the middle line of the abdomen. 
In order to get first a general idea of the peritoneum and its reflections, the 
student should bear in mind that all the abdominal and pelvic viscera are placed 
external to it, and that it is a shut sac superimposed upon the viscera.1 
1 We may disregard, for the present, the fact that the peritoneum in the female is not an abso- 
lutely closed sac, since the Fallopian tubes open into it at their free extremities. THE PERITONEUM. 
861 
Let the student imagine that all the viscera are in their proper positions in the 
abdominal cavity, but uninvested by peritoneum. Upon the top of them is placed 
a large closed sac or bladder, the 
walls of which are of extreme thin- 
ness, and wherever there is a cleft 
between two viscera a process of 
peritoneum derived from the part of 
the sac in contact with the viscera is 
tucked in between them, so as to 
cover the adjacent surfaces of the 
two viscera and separate them from 
each other, and at the same time, by 
becoming adherent to the viscera, 
form an investment for them. Thus 
in Fig. 567 such a diverticulum or 
process may be seen tucked in be- 
tween the under surface of the liver 
and the upper surface of the stomach, 
and, extending between the two as 
far backward as the portal vein, he- 
patic artery, and hepatic duct, which 
it covers on their anterior surfaces, 
forming the anterior layer of what is 
termed the lesser omentum. 
The first of these diverticula or 
processes which must be alluded to, 
because it is the largest, is one which 
is tucked in round the hepatic artery 
as it passes forward and upward to 
the liver and afterward expands into 
a large sac or bag, which covers the 
posterior surface of the liver and 
stomach and the front of the upper 
part of the posterior wall of the ab- 
domen, separating these structures . 
from each other. This large cul-de-sac of peritoneum is called the lesser cavity of 
the peritoneum, but is only a part of the general cavity, differentiated from it by the 
constriction produced at the situation of the hepatic artery. In this respect the 
peritoneum may be compared to an hour-glass with two unequal globes, the smaller 
one constituting the lesser cavity of the peritoneum, the larger one the greater cav- 
ity, and the constriction where the two globes communicate corresponding to the 
constriction in the peritoneum where it hooks round the hepatic artery. This con- 
striction is called the foramen of Winslow. 
A process of this lesser bag of the peritoneum is pushed backward and upward 
behind the liver, extending as far as the under surface of the Diaphragm, the pos- 
terior part of which it covers. At its extremity this process is in contact with a 
process of the greater bag of the peritoneum, which is pushed in from the front, in 
the cleft between the upper surface of the liver and the under surface of the Dia- 
phragm. Where these two layers are in contact (passing down from the Diaphragm 
to the liver) they form some of the ligaments of the liver, thus supporting and hold- 
ing it in position. A second process of the lesser bag of the peritoneum is pushed 
forward on the under surface of the liver, which it invests as far as the transverse 
fissure; here it takes a sudden turn downward to the lesser curvature of the stom- 
ach and forms the posterior layer of the gastro-hepatic or lesser omentum. Between 
the transverse fissure of the liver and the lesser curvature of the stomach it is in 
contact -with the greater bag of the peritoneum, a process of which is sent inward 
between the liver and stomach from the front. Between the two layers are situated 
Fig. 567. 
JPliUirai 
JL W CT 
J?a*ses through 
Forci'mcn 
' oj'li'jcnztujv 
~ Jjfjstr 
v.Qni.entj&mj 
Stomctclt, 
The Reflections of the Peritoneum, as seen in a vertical 
section of the abdomen. 862 
ORGANS OF DIGESTION. 
the hepatic artery, the portal vein, and the hepatic duct. A third process of the 
lesser bag passes from the great curvature of the stomach in front of the small 
intestines for a variable distance, and, being reflected upon itself, ascends to the 
upper surface of the transverse colon. In doing this it forms a loose fold lying 
between the small intestine and the abdominal wall, but contained between two 
layers of the greater bag, which are reflected in a similar way to the under surface 
of the transverse colon from the greater curvature of the stomach. 
This process of the lesser bag, after investing the upper surface of the transverse 
colon, passes back to the spine, forming the upper layer of the transverse mesocolon, 
and, ascending in front of the pancreas and crura of the Diaphragm, reaches the 
under surface of the Diaphragm, where it is continuous with the process of the 
lesser bag, which we have seen lining the under surface of the posterior part of this 
muscle. Thus the lesser cavity of the peritoneum is seen to be a complete sac or 
bag, separating the back and part of the under surface of the liver, the posterior 
wall of the stomach, and the upper surface of the transverse colon from the back 
part of the under surface of the Diaphragm and the upper part of the posterior 
wall of the abdomen. 
The greater cavity of the peritoneum separates the anterior surfaces of the vis- 
cera from the front wall of the abdomen, so that in our comparison of the two 
cavities to an hour-glass it must be borne in mind that they are not in the same 
straight line as the two globes of the hour-glass, but that at the point of constric- 
tion the smaller cavity is bent round the hepatic artery, so as to lie behind the 
greater cavity. 
The greater sac of the peritoneum is placed in front of the viscera, one layer 
being in contact with them, the other lining the inner surface of the anterior wall 
of the abdomen. The layer which is in relation with the viscera sends backward 
diverticula which pass between the various organs, and in certain places comes in 
contact with the peritoneum, forming the lesser bag in the manner described above. 
Thus we have one of these diverticula sent backward between the liver and Dia- 
phragm, covering the anterior part of the under surface of the Diaphragm until it 
meets the peritoneum of the lesser cavity, and covering the upper surface of the 
liver as far backward as the ligaments. The extremity of this diverticulum is in 
contact with a similar diverticulum of the lesser bag, already described, and the 
two layers, when in apposition, form the coronary and lateral ligaments of the 
liver. Another process is sent backward between the under surface of the liver 
and the stomach to meet a similar process of the lesser cavity prolonged from 
behind forward. Where the two are in apposition the lesser or gastro-hepatic 
omentum is formed. A third diverticulum is carried backward to the posterior 
wall of the abdomen between the transverse colon and the small intestine. This 
prolongation covers the under surface of the transverse colon, and forms the under 
layer of the transverse mesocolon and the upper layer of the mesentery; by its 
extremity it is in contact with the posterior wall of the abdomen and covers a part 
of the abdominal aorta. Between the greater curvature of the stomach and the 
transverse colon there is a fold or reduplication of the peritoneum which contains 
between its layers a similar fold from the lesser cavity and forms the apron or great 
omentum. Another fold of the greater bag of the peritoneum is pushed backward 
to the spine between the small intestines and the pelvic viscera. This fold forms 
the lower layer of the mesentery, and by its extremity covers a considerable por- 
tion of the lower part of the abdominal wall and passes over the sacro-vertebral 
angle into the pelvis. From the lower layer of this process, which covers the 
upper part of the pelvic viscera, diverticula are sent doivnward between the pelvic 
viscera, separating them from one another; thus one is sent downward between the 
back of the rectum and the sacrum, another between the rectum and the bladder. 
In the female one is sent down between the rectum and uterus, another between the 
uterus and bladder. These, then, are the various diverticula sent oft' from the pos- 
terior layer of the greater bag of the peritoneum ; the anterior layer simply lines THE PERITONEUM. 
863 
the anterior wall of the abdomen, and is continuous at its extremities with the 
posterior layer. 
The student will perhaps be better able to follow these various folds or reflec- 
tions of the peritoneum by a reference to the accompanying plan (Fig. 568), which 
Fig. 568. 
PROCESS BETWEEN 
DIAPHRAGM AND LIVER 
BETWEEN LIVER AND DIAPHRAGM 
BETWEEN LIVER 
MNP STOMACH 
BETWEEN LIVERt 
ANO STOMACH 
great omentum 
GREAT OMENTUM 
BETWEEN TRANSVERSE 
COLON AND SMALL/ 
intestine! 
BETWEEN SMALL/ 
INTESTINE ANdJI 
PELVIC VISCERA 
BETWEEN SACRUM/ 
AND RECTUM6 
BETWEEN RECTUM | 
AND UTERUS' 
Plan of the Peritoneum. 
should be studied in conjunction with Fig. 567. He must not forget, however, that 
though the lesser and greater cavities of the peritoneum are here represented, for 
the sake of clearness, as quite distinct from each other, they are not really so, but 
that they both form part of one great cavity. 
The reflections of the peritoneum may be traced in two different ways-either 
by considering the folds which form each cavity separately, or by describing them 
together. 
According to the first plan (Fig. 567), the abdomen having been opened, the 
liver should be raised and supported in that position, and the stomach should be 
depressed, when a thin membranous layer is seen passing from the transverse fissure 
of the liver to the upper border of the stomach : this is the lesser or gastro-hepatic 
omentum. It consists of two delicate layers of peritoneum, an anterior and a pos- 
terior, between which are contained the hepatic vessels and nerves. Of these two 
layers, the anterior should first be traced, and then the posterior. 
The anterior layer descends to the lesser curvature of the stomach, and covers 
its anterior surface as far as the great curvature: it descends for some distance in 
front of the small intestines, and, returning upon itself to the transverse colon, 
forms the external layer of the great omentum ; it then covers the under surface of 
the transverse colon, and, passing to the back part of the abdominal cavity, forms 
the inferior layer of the transverse mesocolon. [In the foetus (not to mention the 
still earlier and much simpler arrangement of the peritoneum) the layers of the 
great omentum follow the course shown in Fig. 569. According to Hansen,1 there 
are here five layers, and not three, in front of the transverse colon, as in Fig. 567. 
In the adult, adhesion of the three posterior layers at the point 4 and above oblit- 
t1 Cruveilhier and See, Anat. descrip., ii. 534. j 864 
ORGANS OF DIGESTION. 
erates the cul-de-sac 2 and produces the condition shown in the adult in Fig. 567. 
This is a process similar to the obliteration in 
the adult of the foetal cul-de-sac of the tunica 
vaginalis testis.] It then descends in front of 
the duodenum, the aorta, and vena cava as far 
as the superior mesenteric artery, along which it 
passes to invest the small intestines, and, return- 
ing to the vertebral column, forms the mesentery, 
whilst on either side it covers the ascending and 
descending colon, and is thus continuous with 
the peritoneum lining the walls of the abdomen. 
From the root of the mesentery it descends along 
the front of the spine into the pelvis, and sur- 
rounds the upper part of the rectum, which it 
holds in its position by means of a distinct fold, 
the mesorecticm. Its course in the male and fe- 
male now differs. 
In the male it forms a fold between the rec- 
tum and bladder, the recto-vesical fold [see Fig. 
682,. p. 1022], and ascends over the posterior 
surface of the latter organ as far as its summit. 
In the female it descends into the pelvis in 
front of the rectum, forms a fold between the 
rectum and vagina, the recto-vaginal fold (pouch 
[or cul-de-sac] of Douglas), covers a small part 
of the posterior wall of the vagina, and passes 
on to the uterus, the fundus and body of which 
it covers. From the sides of the uterus it is 
reflected on each side to the wall of the pelvis, forming the broad ligaments; and 
from the anterior surface of the uterus it ascends upon the posterior wall of the 
bladder as far as its summit. From this point it may be traced as in the male, 
ascending upon the anterior parietes of the abdomen, to the under surface of the 
Diaphragm, from which it is reflected upon the liver, forming the upper layer of 
the coronary and the lateral and longitudinal ligaments. It then covers the upper 
and under surfaces of the liver, and at the transverse fissure becomes continuous 
with the anterior layer of the lesser omentum, the point whence its reflection was 
originally traced. 
The posterior layer of the lesser omentum descends to the lesser curvature of 
the stomach, and covers its posterior surface as far as the great curvature; it then 
descends for some distance in front of the small intestines, and, returning upon 
itself to the transverse colon, forms the internal layer of the great omentum; it 
covers the upper surface of the transverse colon, and, passing backward to the 
spine, forms the upper layer of the transverse mesocolon. Ascending in front of 
the pancreas and crura of the Diaphragm, it lines the back part of the under sur- 
face of that muscle, from which it is reflected on to the posterior border of the liver, 
forming the inferior layer of the coronary ligament. From the under surface of the 
liver it may be traced to the transverse fissure, where it is continuous with the pos- 
terior layer of the lesser omentum, the point whence its reflection was originally 
traced. 
The space included in the reflections of this layer of the peritoneum is called the 
lesser cavity of the peritoneum or cavity of the great omentum. It is bounded in front 
by the lesser omentum, the stomach, and the descending part of the great omentum; 
behind by the ascending part of the great omentum, the transverse colon, transverse 
mesocolon, and its ascending layer; above by the liver; and below by the folding 
of the great omentum. This space communicates with the general peritoneal cavity 
through the foramen of Winslow, which is situated behind the right (or free) border 
of the lesser omentum. 
[Fig. 569. 
1, stomach; 2, cul-de-sac existing in foetal 
life, but obliterated by agglutination in 
the adult; 3, transverse colon; 4, the two 
layers of peritoneum forming the cul-de- 
sac (2) become united thus far; 5, small 
intestine (Cruveilhier).] THE PERITONEUM. 
865 
In order to trace the two layers together, we commence at the top of the abdom- 
inal cavity; that is to say, the undei' surface of the Diaphragm. This muscle is 
covered throughout the greater part of its extent by peritoneum, one layer extend- 
ing from its anterior border backward, the other from its posterior border forward. 
Where the two layers meet they are reflected downward to the upper surface of the 
liver, forming the coronary and lateral ligaments of this organ. When these two 
layers reach the liver they again separate to enclose this viscus, the one passing in 
front and the other behind, and they meet again on its under surface at the trans- 
verse fissure. From this fissure they run downward to the lesser curvature of the 
stomach, forming the gastro-hepatic or lesser omentum, and enclosing the hepatic 
artery, the portal vein, and the hepatic duct, which are contained between the two 
folds in this situation. From the lesser curvature of the stomach, the two layers 
pass over the anterior and posterior surfaces of the viscus, enclosing it and meeting 
again at the greater curvature. From this point they pass down in front of the 
small intestines, between this tube and the abdominal wall, and are reflected on 
themselves, passing upward to the transverse colon and forming the apron or great 
omentum. This reflection, therefore, consists of four layers of peritoneum. When 
the two posterior layers of the great omentum in their reflection upward reach the 
transverse colon, they separate to enclose this portion of the intestinal tube, the one 
layer passing above it and the other below.. They meet on its posterior surface and 
pass backward to the vertebral column, forming what is called the transverse meso- 
colon. [Cf. p. 866.] At this point the two layers separate. The one which formed 
the upper surface of the transverse mesocolon, and which belongs to the lesser cav- 
ity, passes upward in front of the pancreas and crura of the Diaphragm to the back 
part of the under surface of the Diaphragm, the point from which the description of 
this layer was commenced. The other, which formed the inferior layer of the trans- 
verse mesocolon, turns downward in front of the duodenum, aorta, and inferior vena 
cava, and can be traced as a single layer in the manner above described, investing 
the small intestines and forming the mesentery; then passing over the sacro-verte- 
bral angle into the pelvis, the viscera of which it partially invests, and finally over 
the posterior surface of the front wall of the abdomen to the under surface of the 
Diaphragm, the point from which the description of this layer was commenced. 
In addition to tracing the peritoneum vertically, as has now been done, it is 
necessary to trace it horizontally. If this is done below the transverse colon, a ref- 
erence to Fig. 567 will show that the circle is extremely simple, as it includes only 
the greater bag of the peritoneum. Above the level of the transverse colon the 
arrangement is more complicated, on account of the existence of two sacs. 
Starting from the linea alba, below the level of the transverse colon, and tracing 
the continuity in a horizontal direction to the right, we find the peritoneum covering 
the internal surface of the abdominal wall almost as far as the anterior border of the 
Quadratus lumborum muscle; it is there reflected over the sides and anterior surface 
of the caecum and ascending colon, fixing them to the abdominal wall, thus forming 
the mesocaecum and the ascending mesocolon, from which it can be traced over the 
kidney to the front of the bodies of the vertebrae. It then passes along the mesen- 
teric vessels to invest the small intestines, and back again to the spine, forming the 
mesentery, between the layers of which are contained the blood-vessels, nerves, lac- 
teals, and glands. Lastly, it passes over the left kidney to the sides and anterior 
surface of the descending colon, forming the descending and sigmoid mesocolon, 
and, reaching the abdominal wall, it passes along it to the middle line of the 
abdomen. 
Above the transverse colon (Fig. 570) the peritoneum can be traced, forming the 
greater and lesser cavities, and their communication through the foramen of Winslow 
can be demonstrated. Commencing in the middle line of the abdomen, the mem- 
brane may be traced lining its anterior wall, and on the right side sending a process 
backward to encircle the obliterated umbilical vein (the round ligament of the liver), 
forming the falciform or longitudinal ligament of the liver. Continuing its course 
to the right, it is reflected over the front of the upper part of the right kidney, 866 
ORGANS OF DIGESTION. 
across the vena cava inferior and aorta, and over the left kidney to the hilum of 
the spleen. From this point it is reflected on to the posterior surface of the stom- 
ach, which it covers, and from 
its right extremity it passes 
around the vessels passing to 
the transverse fissure of the 
liver, and back again to the 
stomach as the lesser omen- 
tum ; and thus it forms the 
anterior boundary of the fora- 
men of Winslow. It now cov- 
ers the front of the stomach, 
and upon reaching the car- 
diac extremity it passes to the 
spleen, which it encloses, form- 
ing the gastro-splenic omen- 
tum. From the hilum of the 
spleen it turns backward to 
reach the abdominal wall, 
along which it courses to 
reach the median line of the 
abdomen. 
The foramen of Winslow 
is bounded in front by the 
lesser omentum, enclosing the vena portae and the hepatic artery and duct; behind 
by the inferior vena cava; above by the lobulus Spigelii; below by the hepatic artery 
curving forward from the coeliac axis. 
The reflections of the peritoneum over the transverse colon are somewhat differ- 
ently described by some authors (Luschka, Holden); and there is no doubt, as was 
long ago pointed out by Haller, that the arrangement in the foetus is different from 
that which has been described above. In the foetus, and even in the young child, 
the two ascending layers of the great omentum can be traced passing together over 
the transverse colon, instead of embracing it, as described above, and passing back 
to the spine as a double fold, which can be separated from the transverse colon and 
transverse mesocolon. Upon reaching the spine the two layers separate: the upper 
one (the inner of the two ascending layers of the great omentum) passes upward in 
front of the pancreas and crura of the Diaphragm, forming the posterior boundary 
of the lesser bag of the peritoneum, in a similar manner to the upper layer of the 
transverse mesocolon in the former description. The other fold (the outer of the 
ascending layer of the great omentum), after reaching the spine, is turned forward 
again on itself as far as the transverse colon, which it covers, and is again reflected 
back to the spine, to pass down in front of the aorta to form the mesentery, in a 
similar manner to the lower layer of the transverse mesocolon in the former descrip- 
tion. Thus the transverse colon is invested by a distinct fold of peritoneum pro- 
longed forward from the spine to surround it, in a very similar manner to the way 
in which the small intestines are surrounded. 
In the adult, however, as a rule, this arrangement disappears. Probably adhe- 
sion of the layers of which the foetal duplication is composed takes place, and then 
absorption, and thus the arrangement is brought about which has been described 
above as most frequently seen in the adult subject. It may be that the foetal dupli- 
cature is " drawn or pushed forward from its place in the progress of visceral 
development, and thus effaced."1 
The viscera thus shown to be almost entirely invested by peritoneum are the 
liver, stomach, spleen, first portion of the duodenum, the jejunum and ileum, the 
transverse colon, sigmoid flexure, upper half of the rectum, the uterus, and ovaries. 
The viscera only partially invested by peritoneum are the descending and trans- 
LESSER 
OMENTUM 
Fig. 570. 
HEPATIC ARTERY/ 
PORTAL VEIN 
AND HEPATIC DUCT 
ROUND LIGAMENT 
OF LIVER 
ABDOM- 
INAL A- 
ORTA 
-VENA 
CAVA 
Transverse Section of Peritoneum (an arrow has been introduced 
into the foramen of Winslow). 
CRURA OF 
DIAPHRAGM 
1 Quain's Anatomy, vol. ii. p. 485. THE PERITONEUM. 
867 
verse portions of the duodenum, the caecum, the ascending and descending colon, the 
middle portion of the rectum, and the upper part of the vagina and posterior wall 
of the bladder. The kidneys, suprarenal capsules, and pancreas are covered by the 
membrane without receiving any special investment from it. 
The lower end of the rectum, the neck, base, and anterior surface of the blad- 
der, the whole of the front, and the lower part of the posterior wall of the vagina 
have no peritoneal covering. 
Numerous folds are formed by the peritoneum, extending between the various 
organs. These serve to hold them in position, and at the same time enclose the 
vessels and nerves proceeding to each part. Some of the folds are called ligaments, 
from their serving to support the organs in position; others, which connect certain 
parts of the intestine with the abdominal wall, constitute the mesenteries; and 
lastly, those which proceed from the stomach to certain viscera in its neighborhood 
are called omenta. 
The Ligaments, formed by folds of the peritoneum, include those of the liver, 
spleen, bladder, and uterus. They will be found described with their respective 
organs. 
The Omenta are the lesser omentum, the great omentum, and the gastro-splenic 
omentum. 
The lesser omentum (g astro-hepatic} is the duplicature which extends between 
the transverse fissure of the liver and the lesser curvature of the stomach. It is 
extremely thin, and consists, as before said, of two layers of peritoneum. At the 
left border its two layers pass on to the end of the oesophagus; but at the right 
border, where it is free, they are continuous, and form a free rounded margin, which 
contains between its layers the hepatic artery, the common bile-duct, the portal vein, 
lymphatics, and the hepatic plexus of nerves,-all these structures being enclosed in 
loose areolar tissue called G-lisson s capsule. Between the layers where they are 
attached to the stomach lie the gastric artery and the pyloric branch of the hepatic, 
anastomosing with it. 
The great omentum (c/astro-colic} is the largest peritoneal fold. It consists of 
four layers of peritoneum, two of which descend from the stomach-one from its ante- 
rior, the other from its posterior, surface-and, uniting at its lower border, descend 
in front of the small intestines as low down as the pelvis; they then turn upon them- 
selves and ascend again as far as the transverse colon, where they separate and 
enclose that part of the intestine. These separate layers may be easily demonstrated 
in the young subject, but in the adult they are more or less inseparably blended. 
The left border of the great omentum is continuous with the gastro-splenic omen- 
tum ; its right border extends as far only as the duodenum. The great omentum is 
usually thin, presents a cribriform appearance, and always contains some adipose 
tissue, which, in fat subjects, accumulates in considerable quantity. Its use appears 
to be to protect the intestines from the cold and to facilitate their movement upon 
each other during their vermicular action. Between its two anterior layers is the 
anastomosis between the right and left gastro-epiploica arteries. 
The gastro-splenic omentum is the fold which connects the concave surface of the 
spleen to the cul-de-sac of the stomach, being continuous by its lower border with 
the great omentum. It contains the splenic vessels and vasa brevia. 
The Mesenteries are-the mesentery proper, the mesocaecum, the ascending, 
transverse, and descending mesocolon, the sigmoid mesocolon, and the mesorectum. 
The mesentery (ptsaov, evrepov}, so called from being connected to the middle of 
the cylinder of the small intestine, is the broad fold of peritoneum which connects 
the convolutions of the jejunum and ileum with the posterior wall of the abdomen. 
Its root, the part connected with the vertebral column, is narrow, about six inches 
in length, and directed obliquely from the left side of the second lumbar vertebra 
to the right sacro-iliac symphysis (Fig. 571). Its intestinal border is much longer; 
and here its two layers separate so as to enclose the intestine and form its peritoneal 
coat. Its breadth, between its vertebral and intestinal border, is about four inches. 
Its upper border is continuous with the under surface of the transverse mesocolon; 868 
ORGANS OF DIGESTION. 
its lower border, with the peritoneum covering the caecum and ascending colon. It 
serves to retain the small intestines in their position, and contains between its layers 
the mesenteric vessels and nerves, the lacteal vessels, and mesenteric glands. 
The mesoccecum, when it exists, serves to connect the back part of the caecum 
Fig. 571. 
Diagram devised by Dr. Delepine to show the lines along which the Peritoneum leaves the Wall of the Abdo- 
men to'invest the Viscera: 1, falciform ligament of liver; 2, right lateral ligament of liver; 3, left lateral 
ligament of liver; 4, vena cava inferior: 5, peritoneum; 6, oesophagus; 7, extra-peritoneal tissue; 8, right 
phrenic artery; 9, diaphragmatic end of gastro-hepatic omentum; 10, coronary artery; 11, gastro-phrenic 
ligament; 12, hepatic artery; 13, gastro-splenic omentum; 14, splenic artery; 15, foramen of Winslow; 16, 
pancreas; 17, duodenum (first part); 18, inferior pancreas duodenum artery; 19, costo-colic ligament; 20, 
colica media; 21, dot between two anterior layers of great omentum; 22, superior mesenteric; 23, trans- 
verse mesocolon; 24, duodenum (third part); 25, bare surface for descending colon; 26, aorta; 27, the two 
layers of the mesentery proper; 28, duodenum (second part); 29, bare surface for ascending colon; 30, right 
and left kidneys; 31, sigmoid mesocolon; 32, superior mesenteric; 33, bare surface for caecum; 34, aorta: 35, 
mesorectum; 36, colica sinistra; 37, bare surface for second part of rectum; 38, colica dextra; 39, left lateral 
false ligament of bladder; 40, vasa intestina; 42, sigmoid artery; 44, superior hemorrhoidal artery; 46, com- 
mon iliac artery [right and left]; 48, internal iliac artery [right and left]; 50, external iliac artery [right and 
left]; 52, epigastric artery; 54, bladder. 
with the right iliac fossa; more frequently the peritoneum passes merely in front 
of this portion of the large intestine. 
The ascending mesocolon is the fold which connects the back part of the ascend- 
ing colon with the posterior wall of the abdomen, and the descending mesocolon 
retains the descending colon in connection with the posterior abdominal wall; more THE STOMACH. 
869 
frequently the peritoneum merely covers the anterior surface and sides of these two 
portions of the intestine. At the place where the transverse colon turns downward 
to form the descending colon a fold of peritoneum is continued upward to the under 
surface of the Diaphragm opposite the tenth and eleventh ribs. This is the costo- 
colic ligament; it passes below the spleen, and serves to support this organ and 
restrain its movements. 
The transverse mesocolon is a broad fold which connects the transverse colon with 
the posterior wall of the abdomen. It is formed by the two ascending layers of the 
great omentum, which, after separating to surround the transverse colon, join behind 
it and are continued backward to the spine, where they diverge in front of the duo- 
denum, as already mentioned. This fold contains between its layers the vessels 
which supply the transverse colon. 
The sigmoid mesocolon is the fold of peritoneum which retains the sigmoid 
flexure in connection with the left iliac fossa. 
The mesorectum is the narrow fold which connects the upper part of the rectum 
with the front of the sacrum. It contains the hemorrhoidal vessels. 
The appendices epiploicce are small pouches of the peritoneum filled with fat and 
situated along the colon and upper part of the rectum. They are chiefly appended 
to the transverse colon. 
[It is especially important that the student notice the fact that the ascending and 
the descending colon, as a rule, are not covered by peritoneum posteriorly, and that 
the kidney lies behind the peritoneum and is not invested by it. The colon in these 
regions and the kidney are therefore accessible for operations without involving the 
peritoneum.] 
The Stomach is the principal organ of digestion. It is the most dilated part 
of the alimentary canal, serving for the solution and reduction of the food, which 
constitutes the process of chymification. It is situated in the left hypochondriac 
and epigastric regions. Its form is irregularly conical, curved upon itself, and pre- 
senting a rounded base turned to the left side. It is placed immediately behind the 
anterior wall of the abdomen, above the transverse colon, below the liver and the 
Diaphragm. Its size varies considerably in different subjects, and also according 
to its state of distension. When moderately full its transverse diameter is about 
twelve inches, its vertical diameter about four. Its weight, according to Clenden- 
ning, is about four ounces and a half. It presents for examination two extremities, 
two orifices, two borders, and two surfaces. 
Its left extremity is called the greater or splenic end. This is the largest part 
of the stomach, and extends two or three inches to the left of the point of entrance 
of the oesophagus. This expanded part is called the great cul-de-sac, or fundus. 
It lies behind the lower ribs, in contact with the spleen, to which it is connected by 
the gastro-splenic omentum. 
The less&r or pyloric end is much smaller than the fundus, and situated on a 
plane anterior and inferior to it. It lies in contact with the wall of the abdomen 
and the under surface of the liver. Its position on the surface of the body varies 
with the degree of distension of the organ. When the stomach is contracted and 
empty the pylorus lies immediately to the right of the linea alba, about two and 
a half or three inches below the end of the gladiolus; when it is fully distended 
it is moved considerably to the right and is situated near the end of the cartilage 
of the eighth rib. 
The oesophageal or cardiac orifice communicates with the oesophagus; it is the 
highest part of the stomach and somewhat funnel-shaped. It is situated about an 
inch to the left of the sternum, behind the seventh costal cartilage of the left side. 
The pyloric orifice communicates with the duodenum, the aperture being guarded 
by a kind of valve-the pylorus. 
The lesser curvature extends between the oesophageal and pyloric orifices, along 
THE STOMACH. 870 
ORGANS OF DIGESTION. 
the upper border of the organ, and is connected to the under surface of the liver by 
the lesser omentum. 
The greater curvature extends between the same two points, along the lower bor- 
der, and gives attachment to the great omentum. The surfaces of the organ are 
limited by these two curvatures. 
The anterior surface is directed upward and forward, and is in relation with the 
Diaphragm, the under surface of the left lobe of the liver, and with the abdominal 
parietes in the epigastric region. 
The posterior surface is directed downward and backward, and is in relation with 
the pancreas and great vessels of the abdomen, the crura of the Diaphragm, and the 
solar plexus. 
The stomach is held in position by the lesser omentum, which extends from the 
transverse fissure of the liver to its lesser curvature, and by a fold of peritoneum 
which passes from the Diaphragm on to the oesophageal end of the stomach-the 
g astro-phrenic ligament: this constitutes the most fixed point of the stomach, whilst 
the pyloric end and greater curvature are the most movable parts; hence when the 
stomach becomes greatly distended the greater curvature is directed forward, whilst 
the anterior and posterior surfaces are directed, the former upward and the latter 
downward.1 
Alterations in Position.-There is no organ in the body the position and connections of which 
present such frequent alterations as the stomach. During inspiration it is displaced downward 
by the descent of the Diaphragm, and elevated by the pressure of the abdominal muscles during 
expiration. Its position in relation to the surrounding viscera is also changed according to the 
empty or distended state of the organ. When empty it occupies only a small part of the left 
hypochondriac region, the spleen lying behind it; the left lobe of the liver covers it in front, 
and the under surface of the heart rests upon it above and in front, being separated from it by 
the left lobe of the liver, besides the Diaphragm and pericardium. This close relation between 
the stomach and the heart explains the fact that in gastralgia the pain is generally referred to 
the heart, and is often accompanied by palpitation and intermission of the pulse. When the 
stomach is distended the Diaphragm is forced upward, contracting the cavity of the chest; hence 
the dyspnoea complained of, from inspiration being impeded. The heart is also displaced 
upward ■ hence the oppression in this region and the palpitation experienced in extreme disten- 
sion of the stomach. Pressure from without, as from tight-lacing, pushes the stomach down 
toward the pelvis. In disease also the position and connections of the organ may be greatly 
changed, from the accumulation of fluid in the chest or abdomen or from alteration in size of 
any of the surrounding viscera. 
On looking into the pyloric end of the stomach the mucous membrane is found 
projecting inward in the front of a circular fold, the pylorus, leaving a narrow cir- 
cular aperture, about half an inch in diameter, by which the stomach communicates 
with the duodenum. 
1 According to Dr. Lesshaft, the professor of anatomy at St. Petersburg, the statements current in 
anatomical textbooks regarding the normal position of the stomach are erroneous. He has made 
careful observations on the point in more than twelve hundred bodies, and has arrived at the follow- 
ing conclusions: The stomach does not, as is usually asserted, lie horizontally in the abdominal cav- 
ity, but vertically, so that the fundus touches the Diaphragm ; the smaller curvature and pylorus are 
to the right, and the larger curvature is to the left. Its position is in the left hypochondrium, and 
the situation of the pylorus is in the vertical line formed by a continuation of the right margin of 
the sternum. If the stomach is enlarged, no one part can be alone displaced, but all parts are equally 
moved by the distension. The arrangement of the muscular fibres of the stomach is such that food 
entering it is moved toward the pylorus, where it can be most thoroughly mixed with the gastric 
juices; and it then passes back along the centre of the cavity to the fundus, where the resistance is 
least. This movement of the food along the wall to the pylorus and back again along the centre is 
rendered possible by the form of the organ, and it is probable that it is to this movement that the 
peculiar shape of the fundus is due. As is well known, the fundus is absent in newly-born children. 
Thus the shape of the stomach determines the long retention of food in the organ for the purposes 
of digestion, and its slow passage through the pylorus. If the transverse colon is distended with 
gas, it may rise to the left of the stomach as high as the fourth intercostal space, and even as high s*s 
the fourth rib. If the coils of the small intestine are similarly distended, the lower part of cne 
stomach may be pressed forward and the stomach may assume a more oblique position. Even a 
large stomach, accustomed to dietetic repletion, maintains a vertical position, but the pylorus is 
moved a little upward and to the right (LcmceZ, March 11, 1882, p. 406). 
On the subject of the position of the stomach the student may refer to a discussion at the Inter- 
national Congress [London, 1881], in which Dr. Lesshaft enunciated this same view. The general 
opinion of the anatomists present appeared to be that the main axis of the stomach was placed 
obliquely, and was therefore opposed to Dr. Lesshaft's views. THE STOMACH. 
871 
The pylorus is formed by a reduplication of the mucous membrane of the stom- 
ach, containing numerous muscular fibres, which are aggregated into a thick circu- 
lar ring, the longitudinal fibres and serous membrane being continued over the fold 
without assisting in its formation. The aperture is occasionally oval. Sometimes 
the circular fold is replaced by two crescentic folds placed one above and the other 
below the pyloric orifice; and more rarely there is only one crescentic fold. 
Structure.-The stomach consists of four coats-a serous, a muscular, an areolar, 
and a mucous coat-together with vessels and nerves. 
The serous coat is derived from the peritoneum, and covers the entire surface of 
the organ, excepting along the greater and lesser curvatures at the points of attach- 
Fig. 572. 
Hehdtic ducts 
Cystic duot- 
Pylorus 
The Mucous Membrane of the Stomach and Duodenum, with the Bile-ducts. 
ment of the greater and lesser omenta; here the two layers of peritoneum leave a 
small triangular space, along which the nutrient vessels and nerves pass. 
The muscular coat (Fig- 573) is situated immediately beneath the serous cover- 
ing. It consists of three sets of fibres-longitudinal, circular, and oblique. 
The longitudinal fibres are most superficial; they are continuous with the lon- 
gitudinal fibres of the oesophagus, radiating in a stellate manner from the cardiac 
orifice. They are most distinct along the curvatures, especially the lesser, but are 
very thinly distributed over the surfaces. At the pyloric end they are more 
thickly distributed, and continuous with the longitudinal fibres of the small 
intestine. 
The circular fibres form a uniform layer over the whole extent of the stomach 
beneath the longitudinal fibres. At the pylorus they are most abundant, and are 
aggregated into a circular ring, which projects into the cavity, and forms, with the 
fold of mucous membrane covering its surface, the pyloric valve. 
The oblique fibres are limited chiefly to the cardiac end of the stomach, where 
they are disposed as a thick uniform layer covering both surfaces, some passing 872 
ORGANS OF DIGESTION. 
obliquely from left to right, others from right to left, round the cardiac orifice. They 
are continuous with the circular fibres of the oesophagus. 
The areolar coat consists of a loose, filamentous, areolar tissue connecting the 
mucous and muscular layers. It is sometimes called the submucous coat. It sup- 
Fig. 573. 
The Muscular Coat of the Stomach. 
ports the blood-vessels previous to their distribution to the mucous membrane; hence 
it is sometimes called the vascular coat. 
The mucous membrane is thick, its surface smooth, soft, and velvety. In the 
fresh state it is of a pinkish tinge at the pyloric end, and of a red or red-brown 
color over the rest of its surface. In infancy it is of a brighter hue, the vascular 
redness being more marked. It is thin at the cardiac extremity, but thicker toward 
the pylorus. During the contracted state of the organ it is thrown into numerous 
plaits or rugse, which for the most part have a longitudinal direction, and are 
most marked toward the lesser end of the stomach and along the greater curva- 
ture (Fig. 572). These folds are entirely obliterated when the organ becomes 
distended. 
Structure of the Mucous Membrane (Fig. 574).-When examined with a 
lens the inner surface of the mucous membrane presents a peculiar honeycomb 
appearance, from being covered with small shallow depressions or alveoli of a 
polygonal or hexagonal form, which vary from y-l-jj- to of an inch in diameter 
and are separated by slightly elevated ridges. In tke bottom of the alveoli are seen 
the orifices of minute tubes, the gastric follicles, which are situated perpendicularly 
side by side in the entire substance of the mucous membrane. 
The gastric follicles are of two kinds, which differ from each other in structure, 
and it is believed also in the nature of their secretion. They are named respectively 
pyloric and peptic glands. They are both tubular in character and are formed of 
a delicate basement membrane, supporting' epithelium. The basement membrane 
consists of flattened transparent epithelial cells, with processes which extend and 
support the epithelium. The pyloric glands are most numerous at the pyloric end 
of the stomach, and from this fact have received their name. They were formerly 
termed mucus-glands, and were supposed to secrete mucus; but, as Klein points 
out, "the cells are serous, not mucous, and the secretion of the glands cannot there- 
fore be mucus." They consist of two or three short closed tubes opening into a THE STOMACH. 
873 
common duct, the external orifice of which is situated at the bottom of an alveolus. 
The caecal tubes are wavy, and are of about equal length with the duct. The tubes' 
and duct are lined throughout with epithelium, the duct being lined by columnar 
cells continuous with the epithelium lining the surface of the mucous membrane of 
the stomach, the tubes with shorter and more cubical cells, which are finely gran- 
ular. The peptic glands are found all over the surface of the stomach. Like the 
pyloric glands, they consist of a duct, into which open two or more caecal tubes. 
The duct, however, in these glands is shorter than in the other variety, sometimes 
not amounting to more than one-sixth of the whole length of the gland; it is lined 
throughout by columnar epithelium. At the point where the terminal tubes open 
into the duct, and which is termed the neck, the epithelium alters, the cells becom- 
Fig. 574. 
Peptic Gastric Gland. 
Pyloric Glands of Stomach. 
Minute Anatomy of Mucous Membrane of Stomach. 
ing much shorter and opaque: the lumen also becomes suddenly constricted, and is 
continued down to the bottom of the tubes as a very fine channel. Here also are 
found, between the epithelium and the basement membrane, large spheroidal, 
coarsely granular cells which have been termed peptic cells, and which produce 
an outward bulging of the basement membrane. They are seen throughout the 
remainder of the tube at intervals, and give it a beaded or varicose appearance. 
Below the neck the terminal tubes, in addition to these isolated spheroidal cells, are 
occupied with finely granular, angular cells (columnar, Klein), leaving only a small 
channel in the centre. They are continuous with the short columnar cells of the 
neck, and are termed the central or chief cells, because they are believed to be prin- 
cipally concerned in the secretion of the gastric juice. The peptic cells, which were 
formerly supposed to possess this office, are now termed parietal cells. Between 
the glands the mucous membrane consists of a connective-tissue framework with 
lymphoid tissue. In places this latter tissue, especially in early life, is collected 
into little masses, which to a certain extent resemble the solitary glands of the 
intestine, and are by some termed the lenticular glands of the stomach. They are 874 
ORGANS OF DIGESTION. 
not, however, so distinctly circumscribed as the solitary glands. The epithelium 
lining the mucous- membrane of the stomach and its alveoli is of the columnar vari- 
ety. Beneath the mucous membrane, and between it and the submucous coat, is a 
thin stratum of involuntary muscular fibre (muscularis mucosae), which in some parts 
consists only of a single longitudinal layer; in others of two layers-an inner cir- 
cular and an outer longitudinal. 
Vessels and Nerves.-The arteries supplying the stomach are the gastric, the 
pyloric and right gastro-epiploic branches of the hepatic, the left gastro-epiploic and 
vasa brevia from the splenic. They supply the muscular coat, ramify in the submu- 
cous coat, and are finally distributed to the mucous membrane. The arrangement 
of the vessels in the mucous membrane is somewhat peculiar. The arteries break 
up at the base of the gastric tubules into a plexus of fine capillaries, which run 
upward between the tubules, anastomosing with each other and ending in a plexus 
of larger capillaries, which surround the mouths of the tubes and also form hexag- 
onal meshes around the alveoli. From these latter the veins arise, and pursue a 
straight course back to the submucous tissue between the tubules, to terminate in 
the splenic and superior mesenteric veins and directly in the portal vein. The 
lymphatics are numerous: they consist of a superficial and deep set, which pass 
through the lymphatic glands found along the two curvatures of the organ. The 
nerves are the terminal branches of the right and left pneumogastric, the former 
being distributed upon the back, and the latter upon the front part of the organ. 
A great number of branches from the sympathetic also supply the organ. 
THE SMALL INTESTINE. 
The small intestine is that part of the alimentary canal in which the chyme is 
mixed with the bile, the pancreatic juice, and the secretions of the various glands 
imbedded in the mucous membrane of the intestine, and where the separation of 
the nutritive principle of the food, the chyle, is effected; this constitutes chyli- 
fication. 
The small intestine is a convoluted tube about twenty feet in length,1 which grad- 
ually diminishes in size from its commencement to its termination. It is contained 
in the central and lower parts of the abdominal and pelvic cavities, surrounded 
above and at the sides by the large intestine; in relation in front with the great 
omentum and abdominal parietes; and connected to the spine by a fold of perito- 
neum, the mesentery. The small intestine is divisible into three portions-the 
duodenum, the jejunum, and the ileum. 
The Duodenum has received its name from being about equal in length to the 
breadth of twelve fingers (eight or ten inches). It is the shortest, the widest, and 
the most fixed part of the small intestine; it has no mesentery, and is only partially 
covered by the peritoneum. Its course presents a remarkable curve, somewhat like 
a horseshoe in form, the convexity being directed toward the right and the concav- 
ity to the left, embracing the head of the pancreas. Commencing at the pylorus, it 
ascends obliquely upward, backward, and to the right, to the under surface of the 
liver; it then descends in front of the right kidney, and passes nearly transversely 
across the front of the spine, terminating in the jejunum on the left side of the sec- 
ond lumbar vertebra. Hence the duodenum has been divided into three portions- 
ascending, descending, and transverse. 
The first or ascending portion (Fig. 575), about two inches in length, is free, 
movable, and nearly completely invested by the peritoneum, which forms the lesser 
1 Treves states that in one hundred cases the average length of the small intestine in the adult 
male was 22 feet 6 inches, and in the adult female 23 feet 4 inches, but that it varies very much, the 
extremes in the male being 31 feet 10 inches in one case and 15 feet 6 inches in another-a difference 
of over 15 feet. He states that he has convinced himself that the length of the bowel is independent 
in the adult of age, height, and weight. [At birth he says the intestine is 9 feet 5 inches in length, 
and that during the first two months it grows about four feet in length. This should teach the special 
need of suitable diet and the danger of intestinal diseases during this early period of life.] THE SMALL INTESTTNE. 
875 
omentum. It is in relation above and in front with the liver and neck of the gall- 
bladder ; behind with the vessels which run between the layers of the lesser omen- 
tum-viz. the hepatic artery and duct and vena portae. This portion of the intestine 
is usually found after death stained with bile, especially on its anterior surface. 
The second or descending portion, about three inches in length, is firmly fixed by 
the peritoneum and pancreas. It passes from the neck of the gall-bladder vertically 
downward, in front of the right kidney, as far as the third lumbar vertebra. It is 
covered by peritoneum only on its anterior surface. It is in relation in front with 
Fig. 575. 
PORTAL 
VEIN 
HEPATIC 
DUCT 
ROUND 
LIGAMENT 
HEPATIC 
ARTERY 
CYSTIC 
ARTERY 
Relations of the Duodenum (a portion of the stomach has been cut away). 
the right arch of the colon and the mesocolon; behind with the front of the right 
kidney; at its inner side is the head of the pancreas and the ductus communis cho- 
ledochus. The common bile-duct and the pancreatic duct perforate the inner side 
of this portion of the intestine obliquely a little below its middle. 
The third or transverse portion, the longest and narrowest part of the duodenum, 
passes across the front of the spine, ascending from the third to the second lumbar 
vertebra, and terminating in the jejunum on the left side of that bone. In front, 
though at some distance from it, is the descending layer of the transverse mesocolon, 876 
ORGANS OF DIGESTION. 
or the divergence of the two layers of that structure, and it is crossed by the supe- 
rior mesenteric vessels; behind it rests upon the aorta, the vena cava, and the crura 
of the Diaphragm ; above it is the lower border of the pancreas, the superior mesen- 
teric vessels passing forward between the two.1 
Vessels and Nerves.-The arteries supplying the duodenum are the pyloric and 
pancreatico-duodenal branches of the hepatic and the inferior pancreatico-duodenal 
branch of the superior mesenteric. The veins terminate in the splenic and superior 
mesenteric. The nerves are derived from the solar plexus. 
The Jejunum (jejunus, empty), so called from being usually found empty after 
death, includes the upper two-fifths of the rest of the small intestine. It commences 
at the duodenum on the left side of the second lumbar vertebra, and terminates in 
the ileum, its convolutions being chiefly confined to the umbilical and left iliac 
regions. The jejunum is wider, its coats thicker, more vascular, and of a deeper 
color than those of the ileum; but there is no characteristic mark to distinguish the 
termination of the one and the commencement of the other. 
The Ileum (eVsZb, to twist), so called from its numerous coils or convolutions, 
includes the remaining three-fifths of the small intestine. It occupies chiefly the 
umbilical, hypogastric, right iliac, and occasionally the pelvic regions, and termi- 
nates in the right iliac fossa by opening into the inner side of the commencement 
of the large intestine. The ileum is narrower, its coats thinner and less vascular, 
than those of the jejunum, a given length 
of it weighing less than the same length of 
the jejunum. 
Structure.-The wall of the small in- 
testine is composed of four coats-serous, 
muscular, areolar, and mucous. 
The serous coat is derived from the 
peritoneum. The first or ascending por- 
tion of the duodenum is almost completely 
surrounded by that membrane ; the second 
or descending portion is covered by it only 
in front; and the third or transverse portion 
lies behind the descending layer of the trans- 
verse mesocolon, by which it is covered in 
front. The remaining portion of the small 
intestine is surrounded by the peritoneum, 
excepting along its attached or mesenteric 
border ; here a space is left for the vessels 
and nerves to pass to the gut. 
The muscular coat consists of two layers 
of fibres-an external or longitudinal, and 
an internal or circular layer. The longitu- 
dinal fibres are thinly scattered over the 
surface of the intestine, and are more distinct along its free border. The cir- 
cular fibres form a thick, uniform layer; they surround the cylinder of the intes- 
tine in the greater part of its circumference, but do not form complete rings. The 
muscular coat is thicker at the upper than at the lower part of the small intestine. 
The areolar or submucous coat connects together the mucous and muscular 
layers. It consists of loose, filamentous, areolar tissue which forms a nidus for 
[Fig. 576. 
From a Vertical Section through a Fold of the Mu- 
cous Membrane of the Jejunum of a Dog: c, the 
mucosa, containing the crypts of Lieberkuhn, and 
projecting as the villi; in, muscularis mucosae; s, 
submucosa (Allen).] 
1 Dr. Bruce Young states that this description of the duodenum, which is the one usually adopted 
in our anatomical textbooks, is incorrect, as it makes no mention of a fourth or terminal vertical por- 
tion. If the point of junction of the jejunum and duodenum be considered to correspond to the spot 
where the gut receives a complete investment of peritoneum, then there is a fairly constant portion, 
about an inch in length, which ascends from the point where the duodenum is usually said to termi- 
nate, on the left side of the vertebral column, and which must be regarded as a fourth part of the 
duodenum. This portion is fixed in this position by a band which extends upward from it, obliquely 
across the aorta to the connective tissue around the cceliac axis and the left crus of the Diaphragm, 
and is termed the musculus suspensorius duodeni, from possessing, according to Trietz, plain muscular 
fibres mixed up with the fibrous tissue of which it is principally made up. THE SMALL INTESTINE. 
877 
the subdivision of the nutrient vessels previous to their distribution to the mucous 
surface. 
The mucous membrane is thick and highly vascular at the upper part of the 
small intestine, but somewhat paler and thinner below. It consists of the following 
structures: next the cellular or submucous coat is a layer of unstriped muscular 
fibre, the muscularis mucosae (Fig. 576, m); internal to this is a quantity of reti- 
form tissue, enclosing in its meshes lymph-corpuscles, and in which the blood-vessels 
and nerves ramify; lastly, a basement membrane, supporting a single layer of epi- 
thelial cells, which throughout the intestines are columnar in character. They are 
granular in appearance and possess a clear oval nucleus. At their superficial or unat- 
tached end they present a distinct layer of highly refracting material marked by ver- 
tical striae, which were formerly believed to be minute channels, by which the chyle 
was taken up into the interior of the cell and by them transferred to the lacteal ves- 
sels of the mucous membrane. 
The mucous membrane presents for examination the following structures con- 
tained within it or belonging to it: 
Simple follicles. 
Duodenal glands. 
Solitary glands. 
Agminate or Peyer's glands. 
Valvulae conniventes. 
Villi. 
Glands. 
The Valvulse Conniventes (valves of Kerkring) are reduplications or foldings 
of the mucous membrane and submucous tissue. Unlike the folds in the stomach, 
they are permanent, and are not obliterated when the intestine is distended. They 
extend transversely across the cylinder of the intestine for about one-half or two- 
thirds of its circumference. The larger folds are about two inches in length and 
one-third of an inch in depth at their broadest part, but the greater number are of 
smaller size. The larger and smaller folds alternate with each other. They are 
not found at the commencement of the duodenum, but begin to appear about one 
or two inches beyond the pylorus. In the lower part of the descending portion, 
below the point where the common choledic and pancreatic ducts enter the intes- 
tine, they are very large and closely approximated. In the transverse portion of 
the duodenum and upper half of the jejunum they are large and numerous; and 
from this point, down to the middle of the ileum, they diminish considerably in 
size. In the lower part of the ileum they almost entirely disappear; hence the 
comparative thinness of this portion of the intestine as compared with the duode- 
num and jejunum. The valvulae conniventes retard the passage of the food along 
the intestines and afford a more extensive surface for absorption. 
The Villi are minute, highly vascular processes projecting from the mucous mem- 
brane of the small intestine throughout its whole extent, and giving to its surface a 
velvety appearance. In shape some are triangular and laminated, others conical or 
cylindrical with clubbed or filiform extremities. They are largest and most nume- 
rous in the duodenum and jejunum, and become fewer and smaller in the ileum. 
Krause estimates their number in the upper part of the small intestine at from fifty 
to ninety in a square line, and in the lower part from forty to seventy, the total 
number for the whole length of the intestine being about four millions. 
The structure of the villi has been studied recently by many eminent anatomists. 
We shall here follow the description of Dr. Watney,1 whose researches have a most 
important bearing on the physiology of that which is the peculiar function of this 
part of the intestine, the absorption of fat. 
The essential parts of a villus are the lacteal vessel, the blood-vessels, the epithe- 
lium, the basement membrane, and muscular tissue of the mucosa, these structures 
being supported and held together by retiform lymphoid tissue. 
These structures are arranged in the following manner: Situated in the centre 
of the villus is the lacteal, terminating near the summit in a blind extremity; run- 
ning along this vessel are unstriped muscular fibres; surrounding it is a plexus of 
1 Phil. Trans., vol. clxvi. Pt. 2. 878 
ORGANS OF DIGESTION. 
capillary vessels, the whole being enclosed by a basement membrane supporting 
columnar epithelium. Those structures which are contained within the basement 
membrane-namely, the lacteal, the muscular tissue, and the blood-vessels-are 
surrounded and enclosed by a delicate reticulum which forms the matrix of the vil- 
lus, and in the meshes of which are found large flattened cells with an oval nucleus, 
and in smaller numbers lymph-corpuscles. These latter are to be distinguished 
from the larger cells of the villus by their behavior with reagents, by their size, 
and by the shape of their nucleus, which is spherical. Transitional forms, how- 
ever, of all kinds are met with between the lymph-corpuscle and the proper cells 
of the villus. 
The lacteals are in some cases double, and in some animals multiple. Situated 
in the axis of the villi, they commence by dilated caecal extremities near to, but 
not quite at, the summit of the villus. The walls are composed of a single layer of 
endothelial cells, the interstitial substance between the cells being continuous with 
the reticulum of the matrix. 
The muscular fibres are derived from the muscularis mucosae, and are arranged 
in bundles around the lacteal vessel, extending from the base to the summit of the 
Fig. 577. 
Diagrammatic Section of a Villus: ep, epithelium only partially shaded in; I, central chyle-vessel: the cells form- 
ing the vessel have been less shaded to distinguish them from the cells of the parenchyma of the villus; m, 
muscle-fibres running up by the side of the chyle-vessel: it will be noticed that each muscle-fibre is sur- 
rounded by the reticulum, and by this reticulum the muscles are attached to the cells forming the mem- 
brana propria, as at e', or to the reticulum of the villus; le, lymph-corpuscles, marked by a spherical nucleus 
and a clear zone of protoplasm; I', upper limit of the chyle-vessel; e, e, e', cells forming the membrana pro- 
pria: it will be seen that there is hardly any difference between the cells of the parenchyma, the endothe- 
lium of the upper part of the chyle-vessel, and the cells of the membrana propria; V, blood-vessels; z, dark 
line at the base of the epithelium formed by the reticulum. It will be seen that the reticulum penetrates 
between all .the other elements of the villus : the reticulum contains thickenings or " nodal points." The 
diagram shows that the cells of the upper part of the villus are larger and contain a larger zone of protoplasm 
than those of the lower part. The cells of the upper part of the chyle-vessel differ somewhat from those of 
the lower part, in that they more nearly resemble the cells of the parenchyma. 
villus, and giving off laterally individual muscle-cells, which are enclosed by the 
reticulum, and by it are attached to the basement membrane. 
The blood-vessels form a plexus between the lacteal and the basement mem- THE SMALL INTESTINE. 
879 
branes, and are enclosed in the reticular tissue; in the interstices of the capillary 
plexus which they form are contained the cells of the villus. 
These structures are surrounded by the basement membrane, which is made up 
of a stratum of endothelial cells and upon which is placed a layer of columnar epi- 
thelium. The reticulum of the matrix is continuous through the basement membrane 
(that is, through the interstitial substance between the individual endothelial cells) 
with the interstitial cement substance of the columnar cells of the surface of the vil- 
lus. Thus we are enabled to trace a direct continuity between the interior of the 
lacteal and the surface of the villus by means of the reticular tissue; and it is along 
this path that, according to Dr. Watney, the chyle passes in the process of absorp- 
tion by the villi. That is to say, it passes through the interstitial substance between 
the epithelium cells, through the interstitial substance of the basement membrane, the 
reticulum of the matrix and the interstitial substance between the endothelial plates 
of the lacteal,-all which structures have been shown to be continuous with one 
another, and, being probably semifluid, do not offer any obstacle to the passage of 
the molecular basis of the chyle. 
All these points are illustrated by the accompanying diagram by Dr. Watney 
(Fig. 577), for which I have to express my best thanks to him; and a compari- 
Fig. 578. 
Epithelial 
Cells 
Fig. 579. 
Nucleus I 
Two Villi (magnified). 
Transverse Section of Crypts of Lieberkuhn (Klein 
and Noble Smith). 
son with Fig. 578 will show the chief points in which the new differs from the old 
description. 
The Simple Follicles, or crypts of Lieberkuhn (Fig. 580), are found in consid- 
erable numbers over every part of the mucous membrane of the small intestine. 
They consist of minute tubular depressions of the mucous membrane arranged per- 
Fig. 580. 
Longitudinal Section of Crypts of Lieberkuhn-goblet-cells seen among the columnar epithelial cells (Klein 
and Noble Smith). 
pendicularly to the surface, upon which they open by small circular apertures. They 
may be seen with the aid of a lens, their orifices appearing as minute dots scattered 
between the villi. Their walls are thin, consisting of a layer of basement membrane 
(which is, in fact, an endothelial membrane), lined by columnar epithelium, and cov- 
ered on their exterior by capillary vessels. 
The Duodenal, or Brunner's Glands, are limited to the duodenum and com- 
mencement of the jejunum. They are small, flattened, granular bodies imbedded 880 
OB GANS OF DIGESTION. 
in the submucous areolar tissue, and open upon the surface of the mucous membrane 
by minute excretory ducts. They are 
most numerous and largest near the py- 
lorus. They may be compared to the ele- 
mentary lobules of a salivary gland spread 
out over a broad surface instead of being 
collected in a mass. They consist of a 
number of tubular alveoli, lined by epi- 
thelium and opening by a single duct on 
the inner surface of the intestine. 
The Solitary Glands soli- 
tarice) are found scattered throughout the 
mucous membrane of the small intestine, 
but are most numerous in the lower part 
of the ileum. They are small, round, 
whitish bodies, from half a line to a line 
in diameter. Their free surface is covered 
with villi, and each gland is surrounded 
by the openings of the follicles of Lieber- 
kuhn. They are now recognized as lymph- 
follicles, and consist of a dense interlacing 
retiform tissue, closely packed with lymph- 
corpuscles and permeated with an abun- 
dant capillary network (Fig. 581). The 
interspaces of the retiform tissue are con- 
tinuous with larger lymph-spaces at the 
base of the gland through which they communicate with the lacteal system. They 
are situated partly in the submucous tissue, partly in the mucous membrane, where 
they form slight projections of its epithelial layer after having penetrated the mus- 
cularis mucosae. The villi which are situated on them are generally absent from the 
very summit (or "cupola," as Frey calls it) of the gland. 
Peyer's Glands [or Patches] (Figs. 581-584) may be regarded as aggregations of 
solitary glands, forming circular or oval patches from twenty to thirty in number, and 
Fig. 581. 
Transverse Section through the equatorial plane of 
three of Peyer's Follicles, from the Rabbit: a, 
capillary network; b, large circular vessels. 
Fig. 582. 
Fig.583. 
Patch of Peyer's Glands, from the 
lower part of the ileum. 
A Portion of Fig. 582 (magnified). 
varying in length from half an inch to four inches. They are largest and most numer- 
ous in the ileum. [Hence the tenderness in the right iliac fossa in typhoid fever, in 
which these patches are inflamed and ulcerated.] In the lower part of the jejunum THE LARGE INTESTINE. 
881 
they are small, of a circular form, and few in number. They are occasionally seen 
in the duodenum. They are placed lengthwise in the intestine, covering the portion 
of the tube most distant from the attachment of the mesentery. Each patch is 
formed of a group of the above-described solitary glands covered with mucous mem- 
Fig. 584. 
Vertical Section of one of Peyer's Patches, from Man, injected through the lymphatic canals: a, villi, with their 
chyle-passages; b, follicles of Lieberkuhn; c, musciilaris mucosse; d, cupola or apex of solitary glands; e, 
mesial zone of glands; f, base of glands: g, points of exit of the chyle-passages from the villi, and entrance 
into the true mucous membrane; h, retiform arrangement of the lymphatics in the mesial zone; i, course 
of the latter at the base of the glands; k, confluence of the lymphatics opening into the vessels of the sub- 
mucous tissue; I, follicular tissue of the fatter. 
brane, and in almost every respect are similar in structure to them. They do not, 
however, as a rule, possess villi on their free surface. Each patch is surrounded 
by a circle of the crypts of Lieberkuhn. They are best marked in the young sub- 
ject, becoming indistinct in middle age, and sometimes altogether disappearing in 
advanced life. They are largely supplied with blood-vessels, which form an abun- 
dant plexus around each follicle, from which fine branches are given off which per- 
meate the lymphoid tissue in the interior of the follicle. 
THE LARGE INTESTINE. 
The large intestine extends from the termination of the ileum to the anus. It is 
about five feet in length, being one-fifth of the whole extent of the intestinal canal. 
It is largest at its commencement at the caecum, and gradually diminishes as far as 
the rectum, where there is a dilatation of considerable size just above the anus. It 
differs from the small intestine in its greater size, its more fixed position, and its 
sacculated form. The large intestine in its course describes an arch which sur- 
rounds the convolutions of the small intestine. It commences in the right iliac 
fossa in a dilated part, the ccecum. It ascends through the right lumbar and hypo- 
chondriac regions to the under surface of the liver; passes transversely across the 
abdomen on the confines of the epigastric and umbilical regions to the left hypo- 
chondriac region ; descends through the left lumbar region to the left iliac fossa, 
where it becomes convoluted and forms the sigmoid flexure; finally, it enters the 
pelvis and descends along its posterior wall to the anus. The large intestine is 
divided into the caecum, colon, and rectum. 
[i At birth, Treves states, the large intestine is 1 foot and 10 inches in length, of which 10 inches 
go to the sigmoid flexure. In the first four months after birth the large intestine grows none in length, 
but a readjustment of its parts takes place without any disturbance of the peritoneum, such that then 
the sigmoid flexure measures only 6 inches, and the rest of the large bowel 1 foot 4 inches.] 882 
ORGANS OF DIGESTION. 
I he Csecum (ccecus, blind) (Fig. 585) is the large blind pouch or cul-de-sac in 
which the large intestine commences. [Its full name is the caput csecum coli; 
that is, the "blind" or closed "head of the colon." Its length is 2| inches and 
its breadth 3 inches.] it is the most dilated 
part of the tube, measuring about two and a 
half inches both in its vertical and transverse 
diameters. Its position varies somewhat; usu- 
ally it is found lying upon the Psoas muscle, 
and so placed that its apex or lowest point is 
just projecting beyond the inner border of 
that muscle, corresponding to a point a little 
to the inner side of the middle of Poupart's 
ligament. Sometimes, however, it is situated 
external to this, in the right iliac fossa, in re- 
lation with the Iliacus muscle; and at other 
times it lies internal to both Psoas and Iliacus, 
either resting on the pelvic brim or altogether 
contained within the pelvis. It is entirely 
enveloped on all sides by peritoneum, which 
after enclosing it is reflected on to the poste- 
rior wall of the abdomen, being continuous 
with the ascending mesocolon when this fold 
exists. The caecum, therefore, lies quite free 
in the abdominal cavity and enjoys a consid- 
erable amount of movement.1 
Attached to its lower and back part is 
the Appendix Vermiformis, a long, narrow, 
worm-shaped tube, the rudiment of the length- 
ened caecum found in all the Mammalia, except 
some of the higher apes and the wombat, in whom an appendix exists. The appen- 
dix varies from three to six inches in length, its average diameter being about equal 
to that of a goose-quill. It is usually directed upward and inward behind the caecum, 
coiled upon itself, and terminates in a blunt point, being retained in its position by 
a fold of peritoneum which sometimes forms a mesentery for it. Its canal is small, 
and communicates with the caecum by an orifice which is sometimes guarded with 
an incomplete valve. Its coats are thick and its mucous lining furnished with a 
large number of solitary glands. 
[Surgical Anatomy.-Inflammation, ulceration, and perforation of the appendix (appen- 
dicitis) from fecal concretions and foreign bodies are very common, and often demand operation 
to give vent to the pus that forms. This, fortunately, is usually a limited abscess, though some- 
times diffuse peritonitis is produced. The pus may usually be reached most readily by an incision 
an inch above Poupart's ligament, followed by a careful dissection into the iliac fossa and toward 
the pelvis, though sometimes it demands abdominal section. 
The caecum and appendix, being free and mobile, are sometimes found in a hernia.] 
Ileo-ccecal Valve.-The lower end of the ileum terminates at the inner and back 
part of the large intestine, opposite the junction of the caecum with the colon. At 
this point the mucous membrane forms two valvular folds which project into the 
large intestine and are separated from each other by a narrow elongated aperture. 
These folds form the ileo-caecal valve {valvula BauhinV). Each fold is semilunar 
in form. The upper one, nearly horizontal in direction, is attached by its convex 
border to the point of junction of the ileum with the colon ; the lower segment to 
the point of junction of the ileum with the caecum. Their free concave margins 
Fig. 585. 
The Csecum and Colon, laid open to show the 
Ileo-csecal Valve. 
1 The above description of the position of the caecum is the one recently given by Mr. Treves in 
his Hunterian lectures. It differs from that usually found in the text-books of anatomy. There is 
no doubt that the description given by Mr. Treves is the correct one. [The variations in position of 
the caecum are due to its mode of development. Dr. R. Matas (N. 0. Med. and Surg. Journ., Dec., 1887) 
has shown that as early as 1861 Luschka pointed out the complete peritoneal investment of the caecum, 
thus antedating Mr. Treves by twenty-four years. None the less credit, however, is due Mr. Treves 
for his valuable lectures.] THE LARGE INTESTINE. 
883 
project into the intestine, separated from one another by a narrow slit-like aperture 
directed transversely. At each end of this aperture the two segments of the valve 
coalesce, and are continued as a narrow membranous ridge around the canal of the 
intestine for a short distance, forming the frcena or retinacula of the valve. The 
left end of this aperture is rounded; the right end is narrow and pointed. 
Each segment of the valve is formed by a reduplication of the mucous membrane 
and of the circular muscular fibres of the intestine, the longitudinal fibres and peri- 
toneum being continued uninterruptedly across from one intestine to the other. 
When these are divided or removed the ileum may be drawn outward, and all 
traces of the valve will be lost, the ileum appearing to open into the large intestine 
by a funnel-shaped orifice of large size. 
The surface of each segment of the valve directed toward the ileum is covered 
with villi, and presents the characteristic structure of the mucous membrane of the 
small intestine; whilst that turned toward the large intestine is destitute of villi, 
and marked with the orifices of the numerous tubular glands peculiar to the mem- 
brane in the large intestine. These differences in structure continue as far as the 
free margin of the valve. 
When the caecum is distended the margins of the- opening are approximated, so 
as to prevent any reflux into the ileum. 
The Colon is divided into four parts-the ascending, transverse, descending, and 
the sigmoid flexure. 
The ascending colon is smaller than the caecum. It passes upward, from its 
commencement at the caecum opposite the ileo-caecal valve, to the under surface of 
the liver on the right of the gall-bladder, where it bends abruptly inward to the 
left, forming the hepatic flexure. It is retained in contact with the posterior wall 
of the abdomen by the peritoneum, which covers its anterior surface and sides, its 
posterior surface being connected by loose areolar tissue with the Quadratus lum- 
borum, right kidney, and descending portion of the duodenum (Figs. 586, 587): 
sometimes the peritoneum almost completely invests it and forms a distinct but 
narrow mesocolon.1 It is in relation in front with the convolutions of the ileum 
and the abdominal parietes; behind, it lies on the Quadratus lumborum muscle and 
right kidney. 
The transverse colon, the longest part of the large intestine, passes trans- 
versely from right to left across the abdomen, opposite the confines of the epigas- 
tric and umbilical zones, into the left hypochondriac region, where it curves down- 
ward beneath the lower end of the spleen, forming the splenic flexure. In its 
course it describes an arch, the concavity of which is directed backward toward 
the vertebral column ; hence the name, transverse arch of the colon. This is the 
most movable part of the colon, being almost completely invested by peritoneum, 
and connected to the spine behind by a large and wide duplicature of that mem- 
brane, the transverse mesocolon. It is in relation by its upper surface with the 
liver and gall-bladder, the great curvature of the stomach, and the lower end of 
the spleen; by its under surface with the small intestines; by its anterior surface 
with the anterior layers of the great omentum and the abdominal parietes; by 
its posterior surface" with the transverse mesocolon and third portion of the 
duodenum. 
The descending colon passes almost vertically downward through the left hypo- 
chondriac and lumbar regions to the upper part of the left iliac fossa, where it ter- 
minates in the sigmoid flexure. It is retained in position by the peritoneum, which 
covers its anterior surface and sides, its posterior surface being connected by areolar 
1 Mr. Treves states that, after a careful examination of 100 subjects, he found that in 52 there was 
neither an ascending nor a descending mesocolon. In 22 there was a descending mesocolon, but no 
trace of a corresponding fold on the other side. In 14 subjects there was a mesocolon to both the 
ascending and the descending segments of the bowel; while in the remaining 12 there was an 
ascending mesocolon, but no corresponding fold on the left side. It follows, therefore, that in per- 
forming lumbar colotomv a mesocolon may be expected upon the left side in 36 per cent, of all cases, 
and on the right in 26 per cent. (7'Ae Anatomy of the Intestinal Canal and Peritoneum in Man, 1885, 
p. 55). 884 
ORGANS OF DIGESTION. 
tissue with the left crus of the Diaphragm, the left kidney, and the Quadratus lum- 
borum (Figs. 586, 587). It is smaller in calibre and more deeply placed than the 
ascending colon, and is more frequently covered with peritoneum on its posterior 
Fig. 586. 
POSTERIOR 
LAMELLA OF 
LUMBAR fascia 
ANTERIOR 
LAMELLA OF 
LUMBAR FASCIA 
MIDDLE 
LAMELLA OF 
lumbar FASCIA 
QUADRATU5 
LUMBCRUM 
LATISSIMU- 
DORSI 
URETER 
surface than the ascending colon (Treves). [It is very important to locate the 
colon accurately from the exterior in operations upon it. It lies half an inch 
behind the mid-point between the anterior and superior spines of the ilium.] 
Diagram of the Relations of the Large Intestine and Kidney, from behind. THE LARGE INTESTINE. 
885 
The sigmoid, flexure is the narrowest part of the colon; it is situated in the 
left iliac fossa, commencing from the termination of the descending colon at the 
Fig. 587. 
RECEPTACULUM 
CHYL1 
GREAT SPLANCHNIC 
NERVE PIERCING 
CRUS 
GREAT SPLANCHNIC 
NERVE PIERCING 
CRUS 
SEMIL UNAR 
GANGLION 
SEMILUNAR 
GANGLION 
The Relations of the Viscera and Large Vessels of the Abdomen (seen from behind, the last dorsal vertebra 
being well raised). 
margin of the crest of the ilium, and ending in the rectum opposite the left sacro- 
iliac3 symphysis. It curves in the first place inward across the Psoas muscle; it 
then descends vertically along the left wall of the pelvis, and finally again passes 886 
ORGANS OF DIGESTION. 
inward to the left sacro-iliac joint, where it becomes the rectum. It is retained in 
its place by a loose fold of peritoneum, the sigmoid mesocolon. It is in relation'in 
front with the small intestines and abdominal parietes. 
[Treves defines the sigmoid flexure as that portion of the large bowel from the 
Psoas muscle to the third sacral vertebra. He includes, therefore, and properly, 
in the sigmoid flexure the first part of the rectum as usually described. It lies not 
in the left iliac fossa, but in the pelvis. It is not usually S- or but a 
large loop, inches long, more like the Greek £1 (omega), the top of the loop 
sometimes even touching the right side of the pelvis.] 
The Rectum is the terminal part of the large intestine, and extends from the 
sigmoid flexure to the anus; it varies in length from six to eight inches, and has 
received its name from being less flexuous than any other part of the intestinal 
canal. It commences opposite the left sacro-iliac symphysis, passes obliquely down- 
ward from left to right to the middle of the sacrum, forming a gentle curve to the 
right side; it then descends in front of the lower part of the sacrum and coccyx, 
presenting a curve with its concavity forward, and near the extremity of the latter 
bone inclines backward to terminate at the anus. The rectum is, therefore, not 
straight, the upper part being directed obliquely from the left side to the median 
line, the middle portion being curved in the direction of the hollow of the sacrum 
and coccyx, and the lower portion presenting a short curve in the opposite direc- 
tion. [This change of direction it is very important to remember in the introduc- 
tion of the finger and of instruments into the rectum. For the first inch they 
should be introduced in the • direction of the umbilicus, and then be directed into 
the hollow of the sacrum.] The rectum is cylindrical, not sacculated like the rest 
of the large intestine; it is narrower at its upper part than the sigmoid flexure, 
gradually increases in size as it descends, and immediately above the anus presents 
a considerable dilatation capable of acquiring an enormous size. The rectum is 
divided into three portions-upper, middle, and lower. [See the preceding 
paragraph.] 
The upper portion, which includes about half the length of the tube, extends 
obliquely from the left sacro-iliac symphysis to the middle of the third piece of the 
sacrum. It is almost completely surrounded by peritoneum, and connected to the 
sacrum behind by a duplicature of that membrane, the mesorectum. It is in rela- 
tion behind with the Pyriformis muscle, the sacral plexus of nerves, and the branches 
of the internal iliac artery of the left side, which separate it from the sacrum and 
sacro-iliac symphysis; in front it is separated, in the male, from the posterior sur- 
face of the bladder; in the female, from the posterior surface of the uterus and its 
appendages by some convolutions of the small intestine. 
The middle portion of the rectum is about three inches in length, and extends 
as far as the tip of the coccyx. It is closely connected to the concavity of the 
sacrum, and covered by peritoneum only on the upper part of its anterior surface. 
It is in relation in front, in the male, with the triangular portion of the base of the 
bladder, the vesiculae seminales, and vasa deferentia, more anteriorly with the under 
surface of the prostate. In the female it is adherent to the posterior wall of the 
vagina. 
The loiver portion is about an inch or an inch and a half in length ; it curves 
backward at the fore part of the prostate gland and terminates at the anus. This 
portion of the intestine receives no peritoneal covering. [According to Dr. J. B. 
Roberts, the peritoneum extends, when the parts are in situ, to within l.f to 2 
inches of the anus, but when the parts are removed the distance is 3-? to 4| inches.] 
It is invested by the Internal sphincter, supported by the Levatores ani muscles, 
and surrounded at its termination by the External sphincter. In the male it is 
separated from the membranous .portion and bulb of the urethra by a triangular 
space, and in the female a similar space intervenes between it and the vagina. This 
space forms by its base the perineum. 
Structure.-The large intestine has four coats-serous, muscular, cellular, and 
mucous. THE LARGE INTESTINE. 
887 
The serous coat is derived from the peritoneum, and invests the different portions 
of the large intestine to a variable extent. The caecum is completely covered by 
the serous membrane. The ascending and descending colon are usually covered 
only in front.1 The transverse colon is almost completely invested, the parts corre- 
sponding to the attachment of the great omentum and transverse mesocolon being 
alone excepted. The sigmoid flexure is nearly completely surrounded, the point 
corresponding to the attachment of the sigmoid mesocolon being excepted. The 
upper part of the rectum is almost completely invested by the peritoneum, the 
middle portion is covered only on its anterior surface, and the lower portion is 
entirely devoid of any serous covering. In the course of the colon and upper part 
of the rectum the peritoneal coat is thrown into a number of small pouches filled 
with fat, called appendices epipdoicce. They are chiefly appended to the transverse 
colon. 
The muscular coat consists of an external longitudinal and an internal circular 
layer of muscular fibres. 
The longitudinal fibres are not found as a uniform layer over the whole surface 
of the large intestine. In the caecum and colon they are especially collected into 
three flat longitudinal bands, each being about half an inch in width. These bands 
commence at the attachment of the appendix vermiformis to the caecum : one, the 
posterior, is placed along the attached border of the intestine; the anterior band, 
the largest, corresponds along the arch of the colon to the attachment of the great 
omentum, but is in front in the ascending and descending colon and sigmoid flexure; 
the third or lateral band is found on the inner side of the ascending and descending 
colon and on the under border of the transverse colon. These bands are nearly 
one-half shorter than the other parts of the intestine, and serve to produce the sac- 
culi which are characteristic of the caecum and colon; accordingly, when they are 
dissected off the tube can be lengthened and its sacculated character becomes lost. 
In the sigmoid flexure the longitudinal fibres become more scattered, but upon its 
lower part and around the rectum they spread out and form a thick uniform layer. 
[In lumbar colotomy the colon may be recognized by these longitudinal bands.] 
The circular fibres form a thin layer over the caecum and colon, being especially 
accumulated in the intervals between the sacculi; in the rectum they form a thick 
layer, especially at its lower end, where they become numerous and form the Inter- 
nal sphincter. 
The areolar coat connects the muscular and mucous layers closely together. 
The mucous membrane in the caecum and colon is pale and of a grayish or pale- 
yellow color. It is quite smooth, destitute of villi, and raised into numerous cres- 
centic folds which correspond to the intervals between the sacculi. In the rectum 
it is thicker, of a darker color, more vascular, and connected loosely to the muscu- 
lar coat, as in the oesophagus. When the lower part of the rectum is contracted its 
mucous membrane is thrown into a number of folds, some of which, near the anus, 
are longitudinal in direction and are effaced by the distension of the gut. Besides 
these there are certain permanent folds of a semilunar shape described by Mr. 
Houston.2 They are usually three in number; sometimes a fourth is found, and 
occasionally only two are present. One is situated near the commencement of the 
rectum on the right side; another extends inward from the left side of the tube, 
opposite the middle of the sacrum; the largest and most constant one projects back- 
ward from the fore part of the rectum opposite the base of the bladder. When a 
fourth is present, it is situated about an inch above the anus on the back of the 
rectum. These folds are about half an inch in width and contain some of the circu- 
lar fibres of the gut. In the empty state of the intestine they overlap each other, 
as Mr. Houston remarks, so effectually as to require considerable manoeuvring to 
conduct a bougie or the finger along the canal of the intestine. Their use seems to 
be " to support the weight of fecal matter and prevent its urging toward the anus, 
where its presence always excites a sensation demanding its discharge." 
As in the small intestine, the mucous membrane consists of a muscular layer, the 
1 See footnote p. 883. 
2 Dub. Hosp. Deports, vol. v. p. 163. 888 
ORGANS OF DIGESTION. 
Fig. 588. 
Surface of mucous membrane, with 
opening of Lieberkuhn's follicles. 
Lieberkuhn's follicles. 
Muscularis mucosae (two layers). 
Submucous connective tissue. 
Solitary Gland. 
Minute Structure of Large Intestine. 
muscularis mucosae; of a quantity of retiform tissue in which the vessels ramify; 
of a basement membrane and epithelium which is of the columnar variety, and 
exactly resembles the epithelium found in the small intestine. The mucous mem- 
brane of this portion of the bowel 
presents for examination simple fol- 
licles and solitary glands. 
The simple follicles are minute 
tubular prolongations of the mucous 
membrane, arranged perpendicularly, 
side by side, over its entire surface; 
they are longer, more numerous, and 
placed in much closer apposition than 
those of the small intestine, and they 
open by minute rounded orifices upon 
the surface, giving it a cribriform ap- 
pearance. 
The solitary glands (Fig. 588) in 
the large intestine are most abundant 
in the ccecum and appendix vermifor- 
mis, but are irregularly scattered also 
over the rest of the intestine. They 
are similar to those of the small in- 
testine. 
The nerves of the intestine are 
derived from the plexuses of sympa- 
thetic nerves around the mesenteric 
arteries. From this source they run 
to a plexus of nerves and ganglia situ- 
ated between the circular and longi- 
tudinal fibres (Auerbach's plexus), 
from which the nervous branches are 
distributed to the muscular coats of 
the intestine. From this plexus a 
secondary plexus is derived (Meiss- 
ner's plexus), which is formed by 
branches which have perforated the circular muscular fibres (Fig. 589). This plexus 
lies between the muscular and mucous coats of the intestine. It is also gangliated, 
Fig. 589. 
Meissner's Plexus (Klein and Noble Smith): a, groups of mul- 
tipolar ganglion-cells, each with a clear nucleus, in the en- 
larged parts of the plexus; b, large single ganglion-cells, 
apparently unipolar, each with a clear nucleus connected 
With the branches of the plexus. THE LIVER. 
889 
and from it the ultimate fibres pass to the muscularis mucosse and to the mucous 
membrane. 
THE LIVER. 
The Liver is a glandular organ of large size intended mainly for the secretion 
of the bile, but effecting also important changes in certain constituents of the blood 
in their passage through the gland. It is situated in the right hypochondriac and 
epigastric regions [Figs. 308 and 309, p. 423], but in the child extends across the 
epigastrium into the left hypochondrium. It is the largest gland in the body, weigh- 
ing from three to four pounds (from fifty to sixty ounces avoirdupois). It measures 
in its transverse diameter from ten to twelve inches, from six to seven in its antero- 
posterior, and is about three inches thick at the back part of the right lobe, which 
is the thickest part. 
Its upper or diaphragmatic surface is convex, directed upward and forward, 
smooth, covered by peritoneum. It is in relation with the under surface of the 
Diaphragm, and below, to a small extent, with the abdominal parietes. The surface 
is divided into two unequal lobes, the right and left, by a fold of peritoneum, the 
suspensory or broad ligament. 
Its under or visceral surface is concave, directed downward and backward, and 
in relation with the stomach and duodenum, the hepatic flexure of the colon, and 
the right kidney and suprarenal capsule. The surface is divided by a longitudinal 
fissure into a right and left lobe. 
The posterior border is rounded and broad, and connected to the Diaphragm by 
the coronary ligament; it is in relation with the aorta, the inferior vena cava, and 
the crura of the Diaphragm. 
The anterior border is thin and sharp, and marked, opposite the attachment of 
the broad ligament, by a deep notch. In adult males this border usually corre- 
sponds with the margin of the ribs, but in women and children it usually projects 
below the ribs. 
The right extremity of the liver is thick and rounded, whilst the left is thin and 
flattened. 
Changes of Position.-The student should make himself acquainted with the different circum- 
stances under which the liver changes its position, as they are of importance in determining the 
existence of enlargement or other disease of the organ. 
Its position varies according to the posture of the body; in the upright and sitting posture it 
usually recedes behind the ribs. Its position varies also with the ascent or descent of the Dia- 
phragm. In a deep inspiration the liver descends below the ribs; in expiration it is raised to 
its ordinary level. Again, in emphysema, where the lungs are distended and the Diaphragm 
descends very low, the liver is pushed down; in some other diseases, as phthisis, where the Dia- 
phragm is much arched, the liver rises very high up. Pressure from without, as in tight-lacing, 
by compressing the lower part of the chest displaces the liver considerably, its anterior edge often 
extending as low as the crest of the ilium, and its convex surface is often at the same time deeply 
indented from pressure of the ribs. Again, its position varies greatly according to the greater or 
less distension of the stomach and intestines. When the intestines are empty the liver descends 
in the abdomen, but when they are distended it is pushed upward. Its relations to surrounding 
organs may also be changed by the growth of tumors or by collections of fluid in the thoracic or 
abdominal cavities. [" Floating" or "wandering" liver, from great relaxation of its ligaments, 
is occasionally though rarely seen.] 
Ligaments.-The ligaments of the liver (Fig. 590) are five in number, four 
being formed of folds of peritoneum: the fifth, the ligamentum teres, is a round 
fibrous cord resulting from the obliteration of the umbilical vein. The ligaments 
are the longitudinal, two lateral, coronary, and round. 
The longitudinal ligament (broad, falciform, or suspensory ligament) is a broad 
and thin antero-posterior peritoneal fold, falciform in shape, its base being directed 
forward, its apex backward. It is attached by one margin to the under surface of 
the Diaphragm and the posterior surface of the sheath of the right Rectus muscle 
as low down as the umbilicus; by its hepatic margin it extends from the notch on 
the anterior margin of the liver as far back as its posterior border. It consists of 890 
ORGANS OF DIGESTION. 
two layers of peritoneum closely united together. Its anterior free edge contains the 
round ligament between its layers. 
The lateral ligaments, two in number, right and left, are triangular in shape. 
They are formed of two layers of peritoneum united, and extend from the sides of 
Fig. 590. 
Right Lob c 
L eft Lobe 
the Diaphragm to the adjacent margins of the posterior border of the organ. The 
left is the longer of the two, and lies in front of the oesophageal opening in the 
Diaphragm. 
The coronary ligament connects the posterior border of the liver to the Dia- 
The Liver, upper surface. 
Fig. 591. 
Left Lobe 
The Liver, under surface. 
phragm. It is formed by the reflection of the peritoneum from the Diaphragm on 
to the upper and lower margins of the posterior border of the organ. The coronary 
ligament consists of two layers, which are continuous on each side with the lateral 
ligaments and in front with the longitudinal ligament. Between the layers a large THE LIVER. 
891 
oval interspace is left uncovered by peritoneum and connected to the Diaphragm by 
firm areolar tissue. This space is subdivided near its left extremity into two parts 
by a deep notch (sometimes a canal), which lodges the inferior vena cava and into 
which open the hepatic veins. 
The round ligament (Fig. 591) is a fibrous cord resulting from the obliteration 
of the umbilical vein. It ascends from the umbilicus, in the anterior free margin 
of the longitudinal ligament, to the notch in the anterior border of the liver, from 
which it may be traced along the longitudinal fissure on the under surface of the 
liver as far back as the inferior vena cava. 
Fissures (Fig. 591).-Five fissures are seen upon the under surface of the liver, 
which serve to divide it into five lobes. They are the longitudinal fissure, the fis- 
sure of the ductus venosus, the transverse fissure, the fissure for the gall-bladder, 
and the fissure for the inferior vena cava. They are arranged in the form of the 
letter A, the apex of the letter corresponding to the posterior margin of the liver, 
its base to the anterior free border. The connecting bar would represent the trans- 
verse fissure; the two converging limbs posterior to this would represent-the left 
one, the fissure for the ductus venosus; the right one, the fissure for the inferior 
vena cava; the two diverging limbs anterior to the cross-bar would represent the 
umbilical fissure (left) and the fissure for the gall-bladder (right). 
The longitudinal fissure is a deep groove which extends from the notch on the 
anterior margin of the liver to the posterior border of the organ. It separates the 
right and left lobes; the transverse fissure joins it at right angles about one-third 
from its posterior extremity and divides it into two parts. The anterior half is 
called the umbilical fissure; it is deeper than the posterior part, and lodges the 
umbilical vein in the foetus or its remains (the round ligament) in the adult. This 
fissure is often partially bridged over by a prolongation of the hepatic substance, 
the pons hepatis. 
The fissure of the ductus venosus is the back part of the longitudinal fissure; 
it is shorter and shallower than the anterior portion. It lodges in the foetus the 
ductus venosus, and in the adult a slender fibrous cord, the obliterated remains of 
that vessel. 
The transverse or portal fissure is a short but deep fissure about two inches in 
length, extending transversely across the under surface of the right lobe nearer to 
its posterior than its anterior border. It joins nearly at right angles with the lon- 
gitudinal fissure. By the older anatomists this fissure was considered the gateway 
(porta) of the liver; hence the large vein which enters at this point was called the 
portal vein. Besides this vein the fissure transmits the hepatic artery and nerves 
and the hepatic duct and lymphatics. At their entrance into the fissure the hepatic 
duct lies in front and to the right, the hepatic artery to the left, and the portal vein 
behind and between the duct and artery. 
The fissure for the gall-bladder (fossa cystis fellece) is a shallow, oblong fossa 
placed on the under surface of the right lobe parallel with the longitudinal fissure. 
It extends from the anterior free margin of the liver, which is occasionally notched 
for its reception, to near the right extremity of the transverse fissure. 
The fissure for the inferior vena cava is a short, deep fissure, occasionally a com- 
plete canal, which extends obliquely upward from a little behind the right extrem- 
ity of the transverse fissure to the posterior border of the liver, where it joins the 
fissure for the ductus venosus. On slitting open the inferior vena cava which is 
contained in it a deep fossa is seen, at the bottom of which the hepatic veins com- 
municate with this vessel. This fissure is separated from the transverse fissure by 
the lobus caudatus and from the longitudinal fissure by the lobulus Spigelii. 
Lobes.-The lobes of the liver, like the ligaments and fissures, are five in num- 
ber-the right lobe, the left lobe, the lobus quadratus, the lobulus Spigelii, and the 
lobus caudatus. 
The right lobe is much larger than the left, the proportion between them being 
as six to one. It occupies the right hypochondrium, and is separated from the left 
lobe, on its upper surface, by the longitudinal ligament; on its under surface, by 892 
ORGANS OF DIGESTION. 
the longitudinal fissure; and in front, by a deep notch. It is of a quadrilateral 
form, its under surface being marked by three fissures-the transverse fissure, the 
fissure for the gall-bladder, and the fissure for the inferior vena cava; and by two 
shallow impressions, one in front (impressio eolica) for the hepatic flexure of the 
colon, and one behind (impressio renalis) for the right kidney and suprarenal 
capsule. 
The left lobe is smaller and more flattened than the right. It is situated in the 
epigastric region. Its upper surface is convex; its under concave surface rests upon 
the front of the stomach, and its posterior border is in relation with the cardiac 
orifice of the stomach. 
The lobus quadratus, or square lobe, is situated on the under surface of the 
right lobe, bounded in front by the free surface of the liver, behind by the trans- 
verse fissure, on the right by the fissure for the gall-bladder, and on the left by the 
umbilical fissure. 
The lobulus Spigelii projects from the back part of the under surface of the 
right lobe. It is bounded in front by the transverse fissure, on the right by the 
fissure for the vena cava, and on the left by the fissure for the ductus venosus. 
The lobus caudatus, or tailed lobe, is a small elevation of the hepatic substance 
extending obliquely outward from the base of the lobus Spigelii to the under sur- 
face of the right lobe. It separates the right extremity of the transverse fissure 
from the commencement of the fissure for the inferior vena cava. 
Vessels.-The vessels connected with the liver are also five in number: they 
are the hepatic artery, the portal vein, the hepatic vein, the hepatic duct, and the 
lymphatics. 
The hepatic artery and portal vein, accompanied by numerous lymphatics and 
nerves, ascend to the transverse fissure between the layers of the gastro-hepatic 
omentum. The hepatic duct, lying in company with them, descends from the trans- 
verse fissure between the layers of the same omentum, and the relative position of 
the three structures is as follows: the hepatic duct lies to the right, the hepatic 
artery to the left, and the portal vein behind and between the other two. They 
are enveloped in a loose areolar tissue, the capsule of Glisson, which accom- 
panies the vessels in their course through the portal canals in the interior of the 
organ. 
The hepatic veins convey the blood from the liver. They commence in the sub- 
stance of the organ, and proceed through it to the deep fossa in its posterior border, 
where they terminate, by three large and several smaller branches, in the inferior 
vena cava. 
The hepatic veins have no cellular investment; consequently, their parietes are 
adherent to the walls of the canals through which they run, so that on a section of 
the organ these veins remain widely open and solitary, and may be easily distin- 
guished from the branches of the portal vein, which are more or less collapsed and 
always accompanied by an artery and duct. 
The lymphatics are large and numerous, consisting of a deep and superficial set. 
They have been already described. 
Nerves.-The nerves of the liver are derived from the hepatic plexus of the 
sympathetic, from the pneumogastric nerves, especially the left, and from the right 
phrenic. 
Structure.-The substance of the liver is composed of lobules held together by 
an extremely fine areolar tissue, and of the ramifications of the portal vein, hepatic 
duct, hepatic artery, hepatic veins, lymphatics, and nerves, the whole being invested 
by a serous and a fibrous coat. 
The serous coat is derived from the peritoneum, and invests the entire surface 
of the organ, excepting at the attachment of its various ligaments and at the bottom 
of the different fissures, where it is deficient. It is intimately adherent to the fibrous 
coat. 
The fibroiis coat lies beneath the serous investment and covers the entire surface 
of the organ. It is difficult of demonstration excepting where the serous coat is THE LIVER. 
893 
deficient. At the. transverse fissure it is continuous with the capsule of Glisson, 
and on the surface of the organ with the areolar tissue separating the lobules. 
The lobules form the chief mass of the hepatic substance; they may be seen 
either on the surface of the organ or by making a section through the gland. They 
are small granular bodies about the size of a millet-seed, measuring from one-twen- 
tieth to one-tenth of an inch in diameter. In the human subject their outline is 
very irregular, but in some of the lower animals (for example, the pig) they are 
well defined, and when divided transversely have a polygonal outline. If divided 
longitudinally they are more or less foliated or oblong. The bases of the lobules 
are clustered round the smallest radicles (sublobular) of the hepatic veins, to which 
each is connected by means of a small branch which issues from the centre of the. 
lobule (intralobular). The remaining part of the surface of each lobule is imper- 
fectly isolated from the surrounding lobules by a thin stratum of areolar tissue, in 
which is contained a plexus of vessels (the interlobular plexus') and ducts. In some 
animals, as the pig, the lobules are completely isolated one from another by this 
interlobular connective tissue. 
If one of the sublobular veins be laid open the bases of the lobules may be seen 
through the thin Avail of the vein, on which they rest arranged in the form of a tes- 
sellated pavement, the centre of each polygonal space presenting a minute aperture, 
the mouth of an intralobular vein (Fig. 592). 
Each lobule is composed of a mass of cells (hepatic cells), surrounded by a dense 
capillary plexus composed of vessels which penetrate from the circumference to the 
centre of the lobule, and terminate in a single straight vein which runs through its 
centre to open at its base into one of the radicles of the hepatic vein. Between the 
Fig. 592. 
Fig. 593. 
Longitudinal Section of a Small Portal Vein and Canal 
(after Kiernan): a, portions of the canal from which the 
vein has been removed; b, side of the portal vein in con- 
tact with the canal; c, the side of the vein which is sepa- 
rated from the canal by the hepatic artery and duct, with 
areolar tissue (Glisson's capsule).; d, internal surface of 
the portal vein, through which are seen the outlines of 
the lobules and the openings, e, of the interlobular veins; 
f, vaginal veins of Kiernan; g, hepatic artery; h, hepatic 
duct. 
h, Longitudinal Section of an Hepatic Vein: a, 
portion of the canal from which the vein 
has been removed; b, orifices of ultimate 
twigs of the vein (intralobular), situated in 
the centre of the lobules (after Kiernan). 
cells are also the minute commencements of the bile-ducts. Therefore in the lobule 
we have all the essentials of a secreting gland; that is to say, (1) cells, by which the 
secretion is formed; (2) blood-vessels, in close relation with the cells, containing the 
blood from which the secretion is derived; and (3) ducts, by which the secretion 
when formed is carried away. Each of these structures will have to be further 
considered. 
1. The hepatic cells are of more or less spheroidal form, but may be rounded, 894 
ORGANS OF DIGESTION. 
flattened, or many-sided from mutual compression. They vary in size from the 
j- to the yoVo an inch diameter. They consist of a honeycomb network 
(Klein) without any cell-wall, and contain one or sometimes two distinct nuclei. In 
the nucleus is a highly refracting nucleolus with granules. Imbedded in the honey- 
comb network are numerous yellow particles, the coloring matter of the bile, and 
oil-globules. The cells adhere together by their surfaces so as to form rows which 
radiate from the centre to the circumference of the lobules. As stated above, they 
are the chief agents in the secretion of the bile. 
2. The Blood-vessels.-The blood in the capillary plexus around the liver-cells 
is brought to the liver principally by the portal vein, but also to a certain extent by 
the hepatic artery. For the sake of clearness the distribution of the blood derived 
from the hepatic artery may be considered first. 
The hepatic artery, entering the liver at the transverse fissure with the portal 
vein and hepatic duct, ramifies with these vessels through the portal canals. It 
gives off vaginal branches which ramify in the capsule of Glisson, and appear to 
be destined chiefly for the nutrition of the coats of the large vessels, the ducts, and 
the investing membranes of the liver. It also gives off capsular branches which 
reach the surface of the organ, terminating in its fibrous coat in stellate plexuses. 
Finally, it gives off interlobular branches which form a plexus on the outer side of 
each lobule to supply its wall and the accompanying bile-ducts. From this offsets 
enter the lobule and end in the capillary network between the cells. Some anato- 
mists, however, doubt whether it transmits any blood directly to the capillary net- 
work. 
T\\q portal vein (Fig. 593) also enters at the transverse fissure and runs through 
the portal canals enclosed in Glisson's capsule, dividing into brandies in its course, 
which finally break up into a plexus (the interlobular plexus) in the interlobular 
spaces between the lobules. In their course they receive the vaginal and capsular 
veins, corresponding to the vaginal and capsular branches of the hepatic artery 
(Fig. 593). Thus it will be seen that all the blood carried to the liver by the 
portal vein and hepatic artery, except perhaps that derived from the interlobular 
branches of the hepatic artery, 
directly or indirectly finds its 
way into the interlobular plexus. 
From this plexus the blood is 
carried into the lobule by fine 
branches which pierce its wall, 
and then converge from the cir- 
cumference to the centre of the 
lobule, forming a number of lon- 
gitudinal vessels which are con- 
nected by transverse or horizon- 
tal branches (Fig. 594). In the 
interstices of the network of ves- 
sels thus formed are situated, as 
before said, the liver-cells; and 
here it is that, the blood being 
brought into intimate connection 
with the liver-cells, the bile is 
secreted. Arrived at the centre 
of the lobule, all these minute 
vessels empty themselves into 
one vein of considerable size 
which runs down the centre of the lobules from apex to base, and is called the 
intralobular vein. At the base of the lobule this vein opens directly into the sub- 
lobular vein, with which the lobule is connected, and which, as before mentioned, 
is a radicle of the hepatic vein. The sublobular veins, uniting into larger and 
larger trunks, end at last in the hepatic veins, which do not receive any intralob- 
Fig. 594. 
Horizontal Section of Liver (dog): the vena portae has been in- 
jected : a, trunk of interlobular vein ; b, trunk of intralobular 
vein. A dense system of capillary vessels lies between them. GALL-BLADDER. 
895 
ular veins. Finally, the hepatic veins, as mentioned at p. 634, converge to form 
three large trunks which open into the vena cava inferior, while that vessel is situ- 
ated m the fissure appropriated to it at the back of the liver. 
3. The Ducts.-Having shown how the blood is brought into intimate relation 
with the hepatic cells in order that the bile may be secreted, it remains now only to 
consider the way in which the secretion, having been formed, is carried away. Sev- 
eral views have prevailed as to the mode of origin of the hepatic ducts: it seems, 
however, to be clear that they commence by little passages which are formed between 
the cells, and which have been termed 
intercellular biliary passages or bile-capil- 
laries (Fig. 595). These passages are 
merely little channels or interspaces left 
between the contiguous surfaces of two 
cells or in the angle where three or more 
liver-cells meet (Fig. 595, c and d\ and 
it seems doubtful whether there is anv 
delicate membrane forming the wall of the 
space. The channels thus formed radiate 
to the circumference of the lobule, and, 
Fig. 595. 
Fig. 59G. 
Microscopical Section from the Liver of a Child Three 
Months Old, hardened in chromic acid. The hepa- 
tic cells (&), with their single nuclei, are separated 
from the capillary wall by a small intervening 
space. The capillaries (a) contain closely com- 
pressed colored, and a few colorless, blood-corpus- 
cles. A few elongated nuclei belonging to the capil- 
lary wall are seen. Within the line of junction 
(septum), between two hepatic cells, the transverse 
section of a biliary duct is seen as a small transpa- 
rent space (c). There is also one at the angle, where 
several of these cells come into contact (d). 
A Transverse Section of a Small Portal Canal and its 
Vessels (after Kiernan): 1, portal vein; 2, interlobu- 
lar branches; 3, vaginal branches; 4, hepatic duct; 
5, hepatic artery. 
piercing its wall, form a plexus (interlobular) between the lobules. From this 
plexus ducts are derived which pass into the portal canals, become enclosed in 
Glisson's capsule, and, accompanying the portal vein and hepatic artery (Fig. 596), 
join with other ducts to form two main trunks which leave the liver at the trans- 
verse fissure and by their union form the hepatic duct. 
GALL-BLADDER. 
The Gall-bladder is the reservoir for the bile; it is a conical or pear-shaped 
membranous sac lodged in a fossa on the under surface of the- right lobe of the 
liver, and extending from near the right extremity of the transverse fissure to the 
anterior free margin of the organ. It is about four inches in length, one inch in 
breadth at its widest part, and holds from eight to ten drachms. It is divided into 
a fundus, body, and neck. The fundus, or broad extremity, is directed downward, 
forward, and to the right, and occasionally projects beyond the anterior border of 
the liver; the body and neck are directed upward and backward to the left. The 
gall-bladder is held in its position by the peritoneum, which in the majority of 
cases passes over its under surface, but the serous membrane occasionally invests 
the gall-bladder, which then is connected to the liver by a kind of mesentery. 
Relations.-The body of the gall-bladder is in relation, by its upper surface, 896 
ORGANS OF DIGESTION. 
with the liver, to which it is connected by areolar tissue and vessels; by its under 
surface with the first portion of the duodenum, occasionally the pyloric end of the 
stomach, and the hepatic flexure of the colon. The fundus is completely invested 
by peritoneum; it is in relation in front with the abdominal parietes, immediately 
below the ninth costal cartilage; behind with the transverse arch of the colon. 
The neck is narrow, and curves upon itself like the italic letter/; at its point of 
connection with the body and with the cystic duct it presents a well-marked con- 
striction. 
When the gall-bladder is distended with bile or calculi the fundus may be felt through the 
abdominal parietes, especially in an emaciated subject: the relations of this sac will also serve 
to explain the occasional occurrence of abdominal biliary fistulse, through which biliary calculi 
may pass out, and of the passage of calculi from the gall-bladder into the stomach, duodenum, 
or colon, which occasionally happens. [The gall-bladder may be reached by laparotomy, and be 
opened (cholecystotomy) for removal of gall-stones, or may itself be entirely excised (cholecyst- 
ectomy.1 When the gall-bladder is distended, the fluid is usually not bile, but mucus secreted 
from its own mucous membrane.] 
Structure.-The gall-bladder consists of three coats-serous, fibrous and mus- 
cular, and mucous. 
The external or serous coat is derived from the peritoneum; it completely invests 
the fundus, but covers the body and neck only on their under surface. 
The middle or fibrous coat is a thin but strong fibrous layer which forms the 
framework of the sac, consisting of dense fibres which interlace in all directions. 
Plain muscular fibres are also found in this coat, disposed chiefly in a longitudinal 
direction, a few running transversely. 
The internal or mucous coat is loosely connected with the fibrous layer. It is 
generally tinged with a yellowish-brown color, and is everywhere elevated into 
minute rugae by the union of which numerous meshes are formed, the depressed 
intervening spaces having a polygonal outline. The meshes are smaller at the 
fundus and neck, being most developed about the centre of the sac. Opposite the 
neck of the gall-bladder the mucous membrane projects inward so as to form a large 
valvular fold. 
The mucous membrane is covered with columnar epithelium and secretes an 
abundance of thick, viscid mucus; it is continuous through the hepatic duct with 
the mucous membrane lining the ducts of the liver, and through the ductus commu- 
nis choledochus with the mucous membrane of the alimentary canal. 
The Biliary Ducts are the hepatic, the cystic, and the ductus communis chole- 
dochus. 
The hepatic duct is formed of two trunks of nearly equal size which issue from 
the liver at the transverse fissure, one from the right, the other from the left lobe; 
these unite and pass downward and to the right for about an inch and a half, to 
join at an acute angle with the cystic duct, and so form the ductus communis chole- 
dochus. 
The cystic duct, the smallest of the three biliary ducts, is about an inch in 
length. It passes obliquely downward and to the left from the neck of the gall- 
bladder, and joins the hepatic duct to form the common duct. It lies in the gastro- 
hepatic omentum in front of the vena portse, the hepatic artery lying to its left side. 
The mucous membrane lining its interior is thrown into a series of crescentic folds; 
from five to twelve in number, which project into the duct in regular succession, 
and are directed obliquely round the tube, presenting much the appearance of a 
continuous spiral valve. They exist only in the human subject. When the duct 
has been distended the interspaces between the folds are dilated, so as to give to its 
exterior a sacculated appearance. 
The ductus communis choledochus, the largest of the three, is the common 
excretory duct of the liver and gall-bladder. It is about three inches in length, 
of the diameter of a goose-quill, and formed by the junction of the cystic and 
hepatic ducts. 
It descends along the right border of the lesser omentum behind the first por- 
f1 See two papers by the American Editor, Amer. Journ. Med. Sei., Jan., 1879, and Oct., 1884.] THE PANCREAS. 
897 
tion of the duodenum, in front of the vena portae and to the right of the hepatic 
artery; it then passes between the pancreas and descending portion of the duo- 
denum, and, running for a short distance along the right side of the pancreatic 
duct near its termination, passes with it obliquely between the mucous and mus- 
cular coats, the two opening by a common orifice upon the summit of a papilla sit- 
uated at the inner side of the descending portion of the duodenum, a little below 
its middle. 
Structure.-The coats of the biliary ducts are an external or fibrous and an 
internal or mucous. The fibrous coat is composed of a strong fibro-areolar tissue, 
with a certain amount of muscular tissue, arranged, for the most part, in a circular 
manner around the duct. The mucous coat is continuous with the lining membrane 
of the hepatic ducts and gall-bladder, and also with that of the duodenum, and, 
like the mucous membrane of these structures, its epithelium is of the columnar 
variety. It is provided with numerous mucous glands, which are tabulated and 
open by minute orifices which are scattered irregularly in the larger ducts. In the 
smaller ducts, which lie in the portal canals in the substance of the liver, are also 
a number of orifices disposed in two longitudinal rows, which were formerly regarded 
as the openings of mucus-glands, but are merely the orifices of tubular recesses, 
which occasionally anastomose and from the sides of which saccular dilatations are 
given off. 
THE PANCREAS. 
Dissection.-The pancreas may be exposed for dissection in three different ways : 1, by rais- 
ing the liver, drawing down the stomach, and tearing through the gastro-hepatic omentum and 
the ascending layer of the transverse mesocolon ; 2, by raising the stomach, the arch of the 
colon, and great omentum, and then dividing the inferior layer of the transverse mesocolon ; 3, 
by dividing the two layers of peritoneum which descend from the great curvature of the stomach 
to form the great omentum, turning the stomach upward, and then cutting through the ascending 
layer of the transverse mesocolon. (See Fig. 567, p. 861.) 
The Pancreas (7rat'-x(oea<, all flesh) is a compound racemose gland analogous in 
its structure to the salivary glands. In shape it is transversely oblong, flattened 
from before backward, and bears some resemblance to a dog s tongue, its right 
extremity being broad and presenting a sort of angular bend from above down- 
ward, called the head, whilst its left extremity gradually tapers to form the tail, 
the intermediate portion being called the body. It is situated transversely across 
the posterior wall of the abdomen at the back of the epigastric and left hypochon- 
driac regions. Its length varies from six to eight inches, its breadth is an inch and 
a half, and its thickness from half an inch to an inch, being greater at its right 
extremity and along its upper border. Its weight varies from two to three and a 
half ounces, but it may reach six ounces. 
The right extremity or head of the pancreas (Fig. 591) is curved upon itself 
from above downward, and is embraced by the concavity of the duodenum. I he 
common bile-duct descends behind between the duodenum and pancreas, and the 
pancreatico-duodenal artery descends in front between the same parts. On the 
posterior aspect of the pancreas is a lobular fold of the gland which passes trans- 
versely to the left behind the superior mesenteric vessels, and thus these vessels are 
embraced by the substance of the gland. It is sometimes detached from the rest of 
the gland, and is called the lesser pancreas. 
The lesser end or tail of the pancreas is narrow; it extends to the left as far as 
the spleen, and is placed over the left kidney and suprarenal capsule. 
The body of the pancreas is convex in front, and covered by the ascending layer 
of the transverse mesocolon and the posterior surface of the stomach. 
The posterior surface is concave, and has the following structures interposed 
between it and the first lumbar vertebra: the superior mesenteric artery and vein, 
the inferior mesenteric vein, the commencement of the vena portae, the vena cava, 
the aorta, the left renal vein, and the crura of the diaphragm. 
The upper border is thick, and has resting upon it, near its centie, the coeliac 898 
ORGANS OF DIGESTION. 
axis; the splenic artery and vein are lodged in a deep groove or canal in this bor 
der; and to the right the first part of the duodenum and the hepatic artery are in 
relation with it. 
The lower border, thinner than the upper, is separated from the transverse portion 
of the duodenum by the superior mesenteric artery and vein ; to the left of these the 
inferior mesenteric vein ascends behind the pancreas to join the splenic vein. 
The pancreatic duct, called the canal of Wirsung, from its discoverer, extends 
transversely from left to right through the substance of the pancreas, nearer to its 
lower than its upper border, and lying nearer its anterior than its posterior surface. 
Fig. 597. 
The Pancreas and its Relations. 
In order to expose it the superficial portion of the gland must be removed. It com- 
mences by the junction of the small ducts of the lobules situated in the tail of the 
pancreas, and running from left to right; it constantly receives the ducts of the 
various lobules composing the gland, and, considerably augmented in size, then 
leaves the head of the pancreas. Descending slightly, it gets into relation with the 
common bile-duct, lying to its left side; and, passing very obliquely through the 
mucous and muscular coats of the duodenum, it terminates by an orifice common to 
it and the ductus communis choledochus upon the summit of an elevated papilla sit- 
uated at the inner side of the descending portion of the duodenum, a little below its 
middle. 
Sometimes the pancreatic duct and ductus communis choledochus open sepa- 
rately into the duodenum. The excretory duct of the lesser pancreas is called the 
ductus pancreaticus minor; it opens into the main duct near the duodenum, and 
sometimes separately into that intestine, at a distance of an inch or more from the 
termination of the principal duct. 
The pancreatic duct, near the duodenum, is about the size of an ordinary quill: 
its walls are thin, consisting of two coats, an external fibrous and an internal 
mucous; the latter is thin, smooth, and furnished near its termination with a few 
scattered follicles. 
Sometimes the pancreatic duct is double up to its point of entrance into the 
duodenum. 
In structure the pancreas resembles the salivary glands. It differs from them, 
however, in certain particulars, and is looser and softer in its texture. It is not THE SPLEEN. 
899 
enclosed in a distinct capsule, but is surrounded by areolar tissue, which dips down 
into its interior and connects together the various lobules of which it is composed. 
Each lobule, like the lobules of the salivary glands, consists of one of the ultimate 
ramifications of the pancreatic duct, terminating in a number of caecal pouches or 
acini. The minute ducts are lined by short columnar epithelium, shorter than that 
found in the salivary ducts, and the acini are wavy and convoluted. They also are 
lined by columnar cells, which present certain characteristics, each cell showing an 
outer homogeneous or faintly striated portion, which becomes deeply stained with 
dyes, and contains the nucleus and an inner granular portion which does not 
easily stain. The lumen of the alveolus is hardly visible, being filled with an 
interstitial substan'ce containing spindle-shaped cells, the centro-acinar cells of 
Langerhans. 
Vessels and Nerves.-The arteries of the pancreas are derived from the 
splenic and the pancreatico-duodenal branches of the hepatic and the superior 
mesenteric. Its veins open into the splenic and superior mesenteric veins. Its 
lymphatics terminate in the lumbar glands. Its nerves are filaments from the sple- 
nic plexus. 
[For the surgery of the Pancreas the student is referred to Dr. N. Senn's elab- 
orate paper, Amer. Journ. Med. Sei., July, 1886.] 
THE SPLEEN. 
The Spleen was formerly classified, together with the thyroid, thymus, and 
suprarenal capsules, as one of the ductless or blood-glands. It possesses no excre- 
tory duct. It is of an oblong flattened form, soft, of very brittle consistence, highly 
vascular, of a dark bluish-red color, and situated in the left hypochondriac region, 
embracing the cardiac end of the stomach. It is invested by peritoneum, and con- 
nected with the stomach by the gastro-splenic omentum. 
Relations.-The external surface is convex, smooth, and in relation with the 
under surface of the Diaphragm, which separates it from the ninth, tenth, and elev- 
enth ribs of the left side. The internal surface is slightly concave, and divided by 
a vertical fissure, the hilum, into an anterior or larger and a posterior or smaller por- 
tion. The hilum is pierced by several irregular apertures for the entrance and exit 
of vessels and nerves. At the margins of the hilum the two layers of peritoneum 
are reflected from the surface of the spleen on to the cardiac end of the stomach, 
forming the gastro-splenic omentum, which contains between its layers the splenic 
vessels and nerves and the vasa brevia. The internal surface is in relation in front 
with the great end of the stomach; below with the tail of the pancreas; and behind 
with the left crus of the Diaphragm and corresponding suprarenal capsule. The 
upper end, thick and rounded, is in relation with the Diaphragm, to which it is 
connected by a fold of peritoneum, the suspensory ligament. The lower end is 
pointed; it is in relation with the left extremity of the transverse arch of the colon. 
The anterior margin is free, rounded, and often notched, especially below. The pos- 
terior margin is rounded, and lies in relation with the left kidney, to which it is 
connected by loose areolar tissue. 
The spleen is held in its position by two folds of peritoneum': one, the gastro- 
splenic omentum, connects it with the stomach ; and the other, the suspensory 
ligament, with the under surface of the Diaphragm. It is also supported by the 
costo-colic ligament, upon which its lower end rests (see p. 869). 
The size and weight of the spleen are liable to very extreme variations at differ- 
ent periods of life in different individuals and in the same individual under different 
conditions. In the adult, in whom it attains its greatest size, it is usually about five 
inches in length, three or four inches in breadth, and an inch or an inch and a half 
in thickness, and weighs about seven ounces. At birth its weight, in proportion to 
the entire body, is almost equal to what is observed in the adult, being as 1 to 350, 
whilst in the adult it varies from 1 to 320 and 400. In old age the organ not only 900 
ORGANS OF DIGESTION. 
decreases in weight, but decreases considerably in proportion to the entire body, being 
as 1 to 700. The size of the spleen is increased during and after digestion, and varies 
considerably according to the state of nutrition of the body, being large in highly- 
fed and small in starved animals. In intermittent and other fevers it becomes much 
enlarged, weighing occasionally from 18 to 20 pounds. 
Structure.-The spleen is invested by two coats-an external serous and an 
internal fibro-elastic coat. 
The external or serous coat is derived from the peritoneum ; it is thin, smooth, 
and in the human subject intimately adherent to the fibro-elastic coat. It invests 
almost the entire organ, being reflected from it at the hilum on to the great end of 
the stomach, and at the upper end of the organ on to the Diaphragm. 
The fibro-elastic coat forms the framework of the spleen. It invests the exte- 
rior of the organ, and at the hilum is reflected inward upon the vessels in the form 
of vaginae or sheaths. From these sheaths, as well as from the inner surface of the 
fibro-elastic coat, numerous small fibrous bands, trabeculce (Fig. 598), are given off 
Fig. 598. 
Transverse Section of the Spleen, showing the Trabecular Tissue and the Splenic Vein and its Branches. 
in all directions; these, uniting, constitute the areolar framework of the spleen. 
The framework of the spleen resembles, therefore, a sponge-like material, consist- 
ing of a number of small spaces or areolce, formed by the trabeculae which are 
given off from the inner surface of the capsule or from the sheaths prolonged 
inward on the blood-vessels; and in these spaces or areolae is contained the splenic 
pulp. 
The proper coat, the sheaths of the vessels, and the trabeculae consist of a dense 
mesh of white and yellow elastic fibrous tissues, the latter considerably predominating. 
It is owing to the presence of this yellow tissue that the spleen possesses a consider- 
able amount of elasticity to allow of the very great variations in size that it presents 
under certain circumstances. In some of the Mammalia, in addition to the usual 
constituents of this tunic, there are found numerous pale, flattened, spindle-shaped, 
nucleated fibres, like unstriped muscular fibres. It is probably owing to this struc- 
ture that the spleen exhibits, when acted upon by the galvanic current, faint traces 
of contractility. 
The proper substance of the spleen or spleen-pulp is a soft mass of a dark red- 
dish-brown color, resembling grumous blood. When examined by means of a thin 
section under the microscope, it is found to consist of a number of branching cells 
and of an intercellular substance. The cells are connective-tissue corpuscles, and THE SPLEEN. 
901 
have been named the sustentacular or supporting cells of the pulp. The processes 
of these branching cells communicate with each other, thus forming a delicate retic- 
ulated tissue in the interior of the areolae formed by the trabeculae of the capsule, 
so that each primary space may be considered to be divided into a number of 
smaller spaces by the junction of these processes of the branching corpuscles. 
These secondary spaces contain blood, in which, however, the white corpuscles are 
found to be in larger proportions than they are in ordinary blood. The sustentacu- 
lar cells are either small, uninucleated, or larger, multinucleated cells; they do not 
become deeply stained with carmine, like the cells of the Malpighian bodies, pres- 
ently to be described (W. Muller), but like them they possess amoeboid movements 
(Cohnheim). In many of them may be seen deep-red or reddish-yellow granules 
of various sizes, which present the characters of the hmmatin of the blood. Some- 
times also unchanged blood-disks are seen included in these cells, but more fre- 
quently blood-disks are found which are altered both in form and color. In fact, 
blood-corpuscles in all stages of disintegration may be noticed to occur within them. 
Klein has recently pointed out that sometimes these cells, in the young spleen, con- 
tain a proliferating nucleus; that is to say, the nucleus is of large size and presents 
a number of knob-like projections, as if small nuclei were budding from it by a 
process of gemmation. This observation is of importance, as it may explain one 
possible source of the colorless blood-corpuscles. 
The interspaces or areolae formed by the framework of the spleen are thus filled 
by a delicate reticulum of branched connective-tissue corpuscles, the interstices of 
which are occupied by blood, and in which the blood-vessels terminate in the man- 
ner now to be described. 
Blood-vessels of the Spleen.-The splenic artery is remarkable for its large size 
in proportion to the size of the organ, and also for its tortuous course. It divides 
into from four to six branches, which enter the hilum of the spleen and ramify 
throughout its substance (Fig. 599), receiving sheaths from an involution of the 
external fibrous tissue. Similar sheaths also invest the nerves and veins. 
Fig. 599. 
Transverse Section of the Human Spleen, showing the Distribution of the Splenic Artery and its Branches, 
Each branch runs in the transverse axis of the organ from within outward, 
diminishing in size during its transit, and giving off in its passage smaller 
branches, some of which pass to the anterior, others to the posterior part. These 
ultimately leave the trabecular sheaths, and terminate in the proper substance of 
the spleen in small tufts or pencils of minute arterioles, which open into the inter- 
stices of the reticulum formed by the branched sustentacular cells. Each of the 
larger branches of the artery supplies chiefly that region of the organ in which the 
branch ramifies, having no anastomosis with the majority of the other branches. 902 
OF DIGESTION. 
The arterioles, supported by the minute trabeculae, traverse the pulp in all direc - 
tions in bundles or pencilii of straight vessels. Their external coat on leaving the 
trabecular sheaths consists of ordinary connective tissue, but it gradually undergoes 
a transformation, becomes much thickened, and converted into a lymphoid material.1 
This change is effected by the conversion of the connective tissue into a cytogenous 
tissue, the bundles of connective tissue becoming looser and laxer, their fibrils more 
delicate, and containing in their interstices an abundance of lymph-corpuscles (W. 
Muller). This lymphoid material is supplied with blood by minute vessels derived 
from the artery with which they are in contact, and which terminates by breaking 
up into a network of capillary vessels. 
The altered coat of the arterioles, consisting of lymphoid tissue, presents here 
and there thickenings of a spheroidal shape-the Malpighian bodies of the spleen. 
These bodies vary in size from about the of an inch to the of an inch in 
diameter. They are merely local expansions or hyperplasiae of the lymphoid tissue, 
of which the external coat of the smaller arteries of the spleen is formed. They 
are most frequently found surrounding the arteriole, which thus seems to tunnel 
them, but occasionally they grow from one side of the vessel only, and present the 
appearance of a sessile bud growing from the 
arterial wall. Klein, however, denies this, and 
says it is incorrect to describe the Malpighian 
bodies as isolated masses of adenoid tissue, but 
that they are always formed around an artery, 
though there is generally a greater amount on 
one side than the other, and that, therefore, in 
transverse sections the artery, in the majority of 
cases, is found in an excentric position. These 
bodies are visible to the naked eye on the sur- 
face of a fresh section of the organ, appearing 
as minute dots of a semi-opaque, whitish color 
in the dark substance of the pulp. In minute 
structure they resemble the adenoid tissue of 
lymphatic glands, consisting of a delicate retic- 
ulum, in the meshes of which lie ordinary lymph- 
oid cells. 
The reticulum of the tissue is made up of 
extremely delicate fibrils, and is comparatively 
open in the centre of the corpuscle, becoming 
closer at the periphery of the body. The cells which it encloses, like the support- 
ing cells of the pulp, are possessed of amoeboid movements, but when treated with 
carmine become deeply stained, and can thus easily be recognized from those of the 
pulp. 
The arterioles terminate in capillaries which traverse the pulp in all directions; 
their walls become much attenuated, lose their tubular character, and the cells of 
the lymphoid tissue of which they are composed become altered, presenting a 
branched appearance and acquiring processes which are directly connected with 
the processes of the sustentacular cells of the pulp (Fig. 601). In this manner the 
capillary vessels terminate, and the blood flowing through them finds its way into 
the interstices of the reticulated tissue formed by the branched connective-tissue 
corpuscles of the splenic pulp. Thus the blood passing through the spleen is 
brought into intimate relation with the elements of the pulp, and no doubt under- 
goes important changes. 
After these changes have taken place the blood is collected from the interstices 
of the tissue by the rootlets of the veins, which commence much in the same way 
as the arteries terminate. Where a vein is about to commence, the connective- 
Fig. 600. 
Part of a Malpighian Capsule of the Spleen 
of Man (Klein and Noble Smith): a, arte- 
rial branch in longitudinal section; b, ade- 
noid tissue, still containing the lymph-cor- 
puscles: only their nuclei are shown; c, 
adenoid reticulum, the lymph-corpuscles 
accidentally removed. 
1 According to Klein, it is the sheath of the small vessel which undergoes this transformation and 
forms a "solid mass of adenoid tissue which surrounds the vessel like a cylindrical sheath" (Atfas 
of Histology, p. 424). THE SPLEEN. 
903 
tissue corpuscles of the pulp arrange themselves in rows in such a way as to form 
an elongated space or sinus. They become changed in shape, being elongated and 
spindle-shaped, and overlap each other at their extremities. They thus form a sort 
of endothelial lining of the path or sinus, which is the radicle of a vein. On the 
outer surface of these cells are seen delicate transverse lines or markings, which 
are due to minute elastic fibrillae arranged in a circular manner around the sinus. 
Thus the channel obtains a continuous external investment, and gradually becomes 
converted into a small vein, which after a time presents a coat of ordinary connec- 
tive tissue lined by a layer of fusiform epithelial cells, which are continuous with 
Fig. 601. 
Section of Spleen, showing the Termination of the small Blood-vessels: a, arterial branch in longitudinal sec- 
tion ; b, supporting cells of spleen-pulp; c, coat of the vessels undergoing lymphoid change; d, coat of the 
vessel continuous with the processes of the supporting cells. 
the supporting cells of the pulp. The smaller veins unite to form larger ones, 
which do not accompany the arteries, but soon enter the trabecular sheaths 
of the capsule, and by their junction form from four to six branches, which 
emerge from the hilum, and, uniting, form the splenic vein, the largest radicle 
of the vena portae. 
The veins are remarkable for their numerous anastomoses, while the arteries 
hardly anastomose at all. 
The lymphatics originate in two ways-i. e. from the sheaths of the arteries and 
in the trabeculae. The former accompany the blood-vessels, the latter pass to the 
superficial lymphatic plexus which may be seen on the surface of the organ. The 
two sets communicate in the interior of the organ. They pass through the lym- 
phatic glands at the hilum and terminate in the thoracic duct. 
• The nerves are derived from branches of the right and left semilunar ganglia 
and right pneumogastric nerve. The Thorax. 
THE Thorax is a conical framework formed partly of bones and partly of the 
soft tissues by which they are connected together. It is supported, and its 
back part is formed, by the middle or dorsal region of the spine. It is narrow 
above, broad below, flattened before and behind, and somewhat cordiform on a 
transverse section. 
Boundaries.-The thorax is bounded in front by the sternum, the six upper 
costal cartilages, the ribs and intercostal muscles; at the sides by the ribs and 
intercostal muscles; and behind by the same structures and the dorsal portion of 
the vertebral column. 
The superior opening of the thorax is bounded on each side by the first rib, in 
front by the upper border of the sternum, and behind by the first dorsal vertebra. 
It is broader from side to side than from before backward, and its direction is for- 
ward and upward. The upper border of the sternum is on a level, in the male, 
with the lower part of the body of the second dorsal vertebra, and in the female 
with the lower part of the body of the third. The antero-posterior diameter is 
about two inches. 
The lotoer opening, or base, is bounded in front by the ensiform cartilage, behind 
by the last dorsal vertebra, and on each side by the last rib, the Diaphragm filling 
in the intervening space. Its direction is obliquely downward and forward, so that 
the cavity of the thorax is much deeper on the posterior than on the anterior wall. 
It is wider transversely than from before backward. Its outer surface is convex, 
but it is more flattened at the centre than at the sides. Its floor is higher on the 
right than on the left side, corresponding in the dead body to the upper border of 
the fifth costal cartilage on the right side, and to the corresponding part of the 
sixth cartilage on the left side. 
The parts which pass through the upper opening of the thorax are, from before 
backward in the middle line, the Sterno-hyoid and Sterno-thyroid muscles, the 
remains of the thymus gland, the trachea, oesophagus, thoracic duct, and the 
Longus colli muscles of each side; at the sides, the arteria innominata, the left 
common carotid and left subclavian arteries, the internal mammary and superior 
intercostal arteries, the right and left venae innominatae, and the inferior thyroid 
veins, the pneumogastric, sympathetic, phrenic, and cardiac nerves, the anterior 
branch of the first dorsal nerve, and the recurrent laryngeal nerve of the left side. 
The apex of each lung, covered by the pleura, also projects through this aperture a 
little above the margin of the first rib. 
The viscera contained in the thorax are the heart, enclosed in its membranous 
bag, the pericardium; and the lungs, invested by the pleurae. 
THE PERICARDIUM. 
The Pericardium is a conical membranous sac in which the heart and the com- 
mencement of the great vessels are contained. It is placed behind the sternum and 
the cartilages of the third, fourth, fifth, sixth, and seventh ribs of the left side, in 
the interval between the pleurae. 
Its apex is directed upward, and surrounds the great vessels about two inches 
above their origin from the base of the heart. Its base is attached to the central 
tendon and part of the adjoining muscular structure of the Diaphragm, extending 
a little farther to the left than to the right side. In front it is separated from the 
904 THE PERICARDIUM. 
905 
sternum by the remains of the thymus gland above and a little loose areolar tissue 
below, and is covered by the margins of the lungs, especially the left. Behind, it 
rests upon the bronchi, the oesophagus, and the descending aorta. Laterally, it is 
covered by the pleurse, the phrenic nerve, with its accompanying vessels, descend- 
ing between the two membranes on either side. 
The pericardium is a fibro-serous membrane, and consists, therefore, of two 
layers, an external fibrous and an internal serous. 
Fig. 602. 
Front View of the Thorax. The ribs and sternum are represented in relation to the lungs, heart, and other 
internal organs: M, mitral valve; t, tricuspid valve; a, aortic semilunar valves; p, pulmonary semilunar 
valves. 
The fibrous layer is a strong, dense membrane. Above, it surrounds the great 
vessels arising from the base of the heart, on which it is continued in the form of 
tubular prolongations which are gradually lost upon their external coat, the strong- 
est being that which encloses the aorta. The pericardium may be traced over these 
vessels to become continuous with the deep layer of the cervical fascia. Below it is 
attached to the central tendon of the Diaphragm, and on the left side to its muscular 
fibres. 
The vessels receiving fibrous prolongations from this membrane are the aorta, 
the superior vena cava, the right and left pulmonary arteries, and the four pulmo- 
nary veins. As the inferior vena cava enters the pericardium through the central 
tendon of the Diaphragm, it receives no covering from the fibrous layer. 
The serous layer invests the heart, and is then reflected on the inner surface of 906 
THE THORAX. 
the pericardium. It consists, therefore, of a visceral and parietal portion. The 
former invests the surface of the heart and the commencement of the great vessels 
to the extent of two inches from their origin; from these it is reflected upon the 
inner surface of the fibrous layer, lining below the upper surface of the central 
tendon of the Diaphragm. The serous membrane encloses the aorta and pulmo- 
nary artery in a single tube, but it only partially covers the superior and inferior 
vena cava and the four pulmonary veins. Its inner surface is smooth and glisten- 
ing, and secretes a thin fluid which serves to facilitate the movements of the heart. 
The arteries of the pericardium are derived from the internal mammary and its 
musculo-phrenic branch, and from the descending thoracic aorta. 
[Surgery of the Pericardium.-In pericarditis with effusion the pericardium may be 
reached in the fifth intercostal space, two to two and a quarter inches to the left of the median 
line (J. B. Roberts).] 
THE HEART. 
[Dissection.-It is well for the student to dissect, along with the human heart, some bullocks', 
sheep's, and chickens' hearts. Besides opening the cavities, sections should be made in various 
directions to obtain a good idea of the relation of parts, especially of the ventricles and their 
walls.] 
The Heart is a hollow muscular organ of a conical form placed between the lungs 
and enclosed in the cavity of the pericardium. 
Position.-The heart is placed obliquely in the chest: the broad attached end, 
or base, is directed upward and backward to the right, and corresponds to the inter- 
val between the fifth and eighth dorsal vertebrae; the apex is directed forward, down- 
ward, and to the left, and corresponds to the interspace between the cartilage of the 
fifth and sixth ribs, three-quarters of an inch to the inner side and an inch and a 
half below the left nipple. The heart is placed behind the lower two-thirds of the 
sternum, and projects farther into the left than into the right cavity of the chest, 
extending from the median line about three inches in the former direction and only 
one and a half in the latter. Its upper border would correspond to a line drawn 
across the sternum on a level with the second costal cartilages, and its lower border 
to a line drawn obliquely, with a slight curve downward, from the articulation of 
the seventh right costal cartilage to the sternum, to the point above mentioned as 
the situation of the apex. The lungs cover a part of the heart, and during inspira- 
tion, when their borders nearly meet behind the sternum, a thin layer of lung covers 
the roots of all the large vessels. Hence the custom of making a patient hold his 
breath [in expiration] whilst examining the sounds of the heart. But a consider- 
able portion of the heart is always uncovered by the lungs where they recede from 
each other below. This "area of the heart's dulness," as it is commonly called, is 
said by Mr. Holden1 to be indicated roughly, but sufficiently for practical purposes, 
by a circle one inch in radius, the centre of which is midway between the left nipple 
and the end of the sternum. The anterior surface of the heart is round and convex, 
directed upward and forward, and formed chiefly by the right ventricle and part of 
the left. Its posterior surface is flattened, and rests upon the Diaphragm, and is 
formed chiefly by the left ventricle. The right border is long, thin, and sharp ; the 
left border short, but thick and round. 
Size.-The heart in the adult measures five inches in length, three inches and a 
half in breadth in the broadest part, and two inches and a half in thickness. The 
prevalent weight in the male varies from ten to twelve ounces, in the female from 
eight to ten : its proportions to the body being as 1 to 169 in males, 1 to 149 in 
females. The heart continues increasing in weight, and also in length, breadth, 
and thickness, up to an advanced period of life: this increase is more marked in 
men than in women. 
Component Parts.-The heart is subdivided by a longitudinal muscular septum 
into two lateral halves, which are named respectively, from their position, right and 
1 Landmarks, Medical and Surgical, p. §41. THE HEART. 
907 
left; and a transverse constriction divides each half of the organ into two cavities, 
the upper cavity on each side being called the auricle, the lower the ventricle. The 
right is the venous side of the heart, receiving into its auricle the dark venous blood 
from the entire body by the superior and 
inferior vena cava and coronary sinus. 
From the right auricle the blood passes 
into the right ventricle, and from the 
right ventricle through the pulmonary 
artery into the lungs. The blood, arte- 
rialized by its passage through the lungs, 
is returned to the left side of the heart 
by the pulmonary veins, which open into 
the left auricle; from the left auricle the 
blood passes into the left ventricle, and 
from the left ventricle is distributed by 
the aorta and its subdivisions through 
the entire body. This constitutes the 
circulation of the blood in the adult. 
The division of the heart into four 
cavities is indicated by grooves upon its 
surface. The great transverse groove 
separating the auricles from the ventri- 
cles is called the auriculo-ventricular 
groove. It is deficient in front from 
being crossed by the root of the pulmo- 
nary artery, and contains the trunks of 
the nutrient vessels of the heart. The 
auricular portion occupies the base of 
the heart, and is subdivided into two 
cavities by a median septum. The two 
ventricles are also separated into a right 
and left by two longitudinal furrows, the 
interventricular grooves, which are situated one on the anterior, the other on the 
posterior surface: these extend from the base to the apex of the organ, the former 
being situated nearer to the left border of the heart, and the latter to the right. It 
follows, therefore, that the right ventricle forms the greater portion of the anterior 
surface of the heart, and the left ventricle more of its posterior surface. 
Each of these cavities should now be separately examined. 
The Right Auricle is a little larger than the left, its walls somewhat thinner, 
measuring about one line, and its cavity is capable of containing about two ounces. 
It consists of two parts-a principal cavity, or sinus venosus, and an appendix 
auriculce. 
The sinus is the large quadrangular cavity placed between the two venae cavae; 
its walls are extremely thin; it is connected below with the right ventricle, and 
internally with the left auricle, being free in the rest of its extent. 
The appendix auriculae, so called from its fancied resemblance to a dog's ear, is 
a small conical muscular pouch, the margins of which present a dentated edge. It 
projects from the sinus forward and to the left side, overlapping the root of the 
aorta. 
To examine the interior of the auricle, an incision should be made along its right border from 
the entrance of the superior vena cava to that of the inferior. A second cut is to be made from 
the centre of this first incision to the tip of the auricular appendix, and the flaps raised. 
The internal surface of the right auricle is smooth, except in the auricle and 
adjacent part of the anterior wall of the sinus venosus, where it is thrown into 
parallel ridges. 
Fig. 603. 
Foramina, 
Thtirsii 
Tultrcl* 
Bristle, 'passed through 
RightAuriculo-Ventricul(tr opening 
The Right Auricle and Ventricle laid open, the anterior 
walls of both being removed. 908 
THE THORAX. 
It represents the following parts for examination: 
Superior vena cava. 
Inferior vena cava. 
Coronary sinus. 
Foramina Thebesii. 
Auriculo-ventricular. 
Valves. 
Eustachian. 
Coronary. 
Openings. 
Musculi pectinati. 
Tuberculum Loweri. 
Relics of Foetal Structure. 
Annulus ovalis. 
Fossa ovalis. 
The superior vena cava returns the blood from the upper half of the body, and 
opens into the upper and back part of the auricle, the direction of its orifice being 
downward and forward. 
The inferior vena cava, larger than the superior, returns the blood from the 
lower half of the body, and opens into the lowest part of the auricle near the sep- 
tum, the direction of its orifice being upward and inward. The direction of a 
current of blood through the superior vena cava would consequently be toward the 
auriculo-ventricular orifice, whilst the direction of the blood through the inferior 
cava would be toward the auricular septum. This is the normal direction of the 
two currents in foetal life. 
The tuberculum Loweri is a small projection on the right wall of the auricle 
between the two cavse. This is most distinct in the hearts of quadrupeds; in man 
it is scarcely visible. It was supposed by Lower to direct the blood from the supe- 
rior cava toward the auriculo-ventricular opening. 
The coronary sinus opens into the auricle between the inferior vena cava and 
the auriculo-ventricular opening. It returns the blood from the substance of the 
heart, and is protected by a semicircular fold of the lining membrane of the auricle, 
the coronary valve. The sinus before entering the auricle is considerably dilated- 
nearly to the size of the end of the little finger. Its wall is partly muscular, and 
at its junction with the great coronary vein is somewhat constricted, and furnished 
with a valve consisting of two unequal segments. 
foramina Thebesii are numerous minute apertures, the mouths of small veins 
(pence cordis minimcef which open on various parts of the inner surface of the auricle. 
They return the blood directly from the muscular substance of the heart. Some of 
these foramina are minute depressions in the walls of the heart, presenting a closed 
extremity. 
The auriculo-ventricular opening is the large oval aperture of communication 
between the auricle and the ventricle to be presently described. 
The Eustachian valve is situated between the anterior margin of the inferior 
vena cava and the auriculo-ventricular orifice. It is semilunar in form, its convex 
margin being attached to the wall of the vein, its concave margin, which is free, 
terminating in two cornua, of which the left is attached to the anterior edge of the 
annulus ovalis, the right being lost on the wall of the auricle. The valve is formed 
by a duplicature of the lining membrane of the auricle containing a few muscular 
fibres. 
In the foetus this valve is of large size, and serves to direct the blood from the 
inferior vena cava through the foramen ovale into the left auricle. 
In the adult it is occasionally persistent, and may assist in preventing the 
reflux of blood into the inferior vena cava; more commonly it is small, and its free 
margin presents a cribriform or filamentous appearance; occasionally it is altogether 
wanting. 
The coronary valve (valve of Thebesius) is a semicircular fold of the lining mem- 
brane of the auricle protecting the orifice of the coronary sinus. It prevents the 
regurgitation of blood into the sinus during the contraction of the auricle. This 
valve is occasionally double. 
The fossa ovalis is an oval depression corresponding to the situation of the fora- 
men ovale in the foetus. It is situated at the lower part of the septum auricularum, 
above the orifice of the inferior vena cava. THE HEART. 
909 
The annulus ovalis is the prominent oval margin of the foramen ovale. It is 
most distinct above and at the sides; below it is deficient. A small slit-like 
valvular opening is occasionally found at the upper margin of the fossa ovalis 
which leads upward, beneath the annulus, into the left auricle, and is the remains 
of the aperture between the two auricles in the foetus. 
The musculi pectinati are small, prominent muscular columns which run across 
the inner surface of the appendix auriculae and adjoining portion of the wall of the 
sinus. They have received the name pectinati from the fancied resemblance they 
bear to the teeth of a comb [Latin, pecten\. 
The Rig-lit Ventricle is triangular in form and extends from the right auricle to 
near the apex of the heart. Its anterior or upper surface is rounded and convex 
and forms the larger part of the front of the heart. Its posterior or under surface 
is flattened, rests upon the Diaphragm, and forms only a small part of the back of 
the heart. Its inner wall is formed by the partition between the two ventricles, the 
septum ventriculorum, the surface of which is convex and bulges into the cavity of 
the right ventricle. Its upper and inner angle is prolonged into a conical pouch, 
the infundibulum or conus arteriosus, from which the pulmonary artery arises. 
The walls of the right ventricle are thinner than those of the left, the proportion 
between them being as 1 to 3. The wall is thickest at the base, and gradually 
becomes thinner toward the apex. The cavity, which equals that of the left ven- 
tricle, is capable of containing about three fluidounces.1 
To examine the interior an incision should be made a little to the right of the anterior ven- 
tricular groove from the pulmonary artery to the apex of the heart, and should be carried up 
from thence along the right border of the ventricle as far as the auriculo-ventricular opening. 
The following parts present themselves for examination: 
Openings. 
Auriculo-ventricular. 
Opening of the pulmonary artery. 
Valves. . 
Tricuspid. 
Semilunar. 
And a muscular and tendinous apparatus connected with the tricuspid valve: 
Columnae carnem. 
Chordae tendinese. 
The auriculo-ventricular orifice is the large oval aperture of communication 
between the auricle and ventricle. It is situated at the base of the ventricle near 
the right border of the heart, and corresponds to the centre of the sternum between 
the fourth costal cartilages. The opening is about an inch in diameter,2 oval from 
side to side, surrounded by a fibrous ring covered by the lining membrane of the 
heart, and rather larger than the corresponding aperture on the left side, being 
sufficiently large to admit the ends of four fingers. It is guarded by the tricuspid 
valve. 
The opening of the pulmonary artery is circular in form and situated at the sum- 
mit of the conus arteriosus [the conical portion of the cavity of each ventricle from 
which the aorta and the pulmonary artery respectively arise], close to the septum 
ventriculorum. It is placed on the left side of the auriculo-ventricular opening, 
upon the anterior aspect of the heart, and corresponds to the articulation of the 
third costal cartilage of the left side with the sternum. Its orifice is guarded by 
the pulmonary semilunar valves. 
The tricuspid valve consists of three segments of a triangular or trapezoidal 
1 Morrant Baker says that, "taking the means of various estimates, it may be inferred that each 
ventricle is able to contain four to six ounces of blood" (Kirke's Physiology, 10th edition, p. 156). 
2 In the Pathological Transactions, vol. vi. p. 119, Dr. Peacock has given some careful researches 
upon the weight and dimensions of the heart in health and disease. He states, as the result of his 
investigations, that in the healthy adult heart the right auriculo-ventricular aperture has a mean 
circumference of 54.4 lines, or 4fJ inches; the left auriculo-ventricular aperture a mean circumfer- 
ence of 44.3 lines, or 3ff inches; the pulmonic orifice of 40 lines, or 3|| inches; and the aortic ori- 
fice of 35.5 lines, or 3/¥ inches; but the dimensions of the orifices varied greatly in different cases, 
the auriculo-ventricular aperture having a range of from 45 to 60 lines, and the others in the same 
proportion. 910 
THE THORAX. 
shape formed by a duplicature of the lining membrane of the heart, strengthened 
by a layer of fibrous tissue, and containing, according to Kurschner and Senac, 
muscular fibres. These segments are connected by their bases to the auriculo- 
ventricular orifice and by their sides with one another, so as to form a continuous 
annular membrane which is attached round the margin of the auriculo-ventricular 
opening, their free margins and ventricular surfaces affording attachment to a num- 
ber of delicate tendinous cords, the chordce tendinece. The largest and most mova- 
ble segment is placed toward the left side of the auriculo-ventricular opening, inter- 
posed between that opening and the pulmonary artery. Another segment corre- 
sponds to the front of the ventricle, and a third to its posterior wall. The central 
part of each segment is thick and strong; the lateral margins are thin and indented. 
The chordae tendineae are connected with the adjacent margins of the principal seg- 
ments of the valve, and are further attached to each segment in the following man- 
ner: 1. Three or four reach the attached margin of each segment, where they are 
continuous with the auriculo-ventricular tendinous ring. 2. Others, four to six in 
number, are attached to the central thickened part of each segment. 3. The most 
numerous and finest are connected with the marginal portion of each segment. 
The columnce carnece are the rounded muscular columns which project from 
nearly the whole of the inner surface of the ventricle, excepting near the opening 
of the pulmonary artery, where the wall becomes smooth. They may be classified, 
according to their mode of connection with the ventricle, into three sets: The first 
set merely form prominent ridges on the inner surface of the ventricle, being 
attached by their entire length on one 
side as well as by their extremities; the 
second set are attached by their two ex- 
tremities, but are free in the rest of their 
extent; wdiilst the third set (musculi pa- 
pillar es), three or four in number, are 
attached by one extremity to the wall of 
the heart, the opposite extremity giving 
attachment to the chordce tendinece. The 
tricuspid valve is situated behind the mid- 
dle of the sternum, about the level of the 
fourth costal cartilage. 
The semilunar valves, three in num- 
ber,1 guard the orifice of the pulmonary 
artery. They consist of three semicircu- 
lar folds, two anterior (right and left) and 
one posterior, formed by a duplicature of 
the lining membrane, strengthened by fib- 
rous tissue. They are attached by their 
convex margins to the wall of the artery, 
at its junction with the ventricle, the 
straight border being free and directed 
upward in the course of the vessel, against 
the sides of which the valve-flaps are press- 
ed during the passage of the blood along 
the artery. The free margin of each is 
somewhat thicker than the rest of the 
valve, is strengthened by a bundle of 
tendinous fibres, and presents at its mid- 
dle a small projecting thickened nodule, 
called corpus Arantii.2 From this nodule tendinous fibres radiate through the valve 
Fig. 604. 
Bristlepasted tfir. 
.Left Auric al o-Ventr 
opening 
passed thr. Aortic opening 
The Left Auricle and Ventricle laid open, the posterior 
walls of both being removed. 
1 The pulmonary semilunar valves have been found to be two in number, instead of three (Dr. 
Hand of St. Paul, Minn., in the North-western Med. and Surg. Journ., July, 1873); and the same 
variety is more frequently noticed in the aortic semilunar valves. 
2 In former editions, as well as in other textbooks on anatomy, these little nodules have been THE HEART. 
911 
to its attached margin, and these fibres form a constituent part of its substance 
throughout its whole extent, excepting two narrow lunated portions placed on either 
side of the nodule immediately behind the free margin; here the valve is thin and 
formed merely by the lining membrane. During the passage of the blood along the 
pulmonary artery these valves are pressed against the sides of the cylinder, and the 
course of the blood along the tube is uninterrupted ; but during the ventricular dias- 
tole, when the current of blood along the pulmonary artery is checked and partly 
thrown back by its elastic walls, these valves become immediately expanded and 
effectually close the entrance of the tube. When the valves are closed the lunated 
portions of each are brought into contact with one another by their opposed surfaces, 
the three corpora Arantii filling up the small triangular space that would be other- 
wise left by the approximation of the three semilunar valves. 
Between the semilunar valves and the commencement of the pulmonary artery 
are three pouches or dilatations, one behind each valve. These are the pulmonary 
sinuses (sinuses of Valsalva}. Similar sinuses exist between the semilunar valves 
and the commencement of the aorta ; they are larger than the pulmonary sinuses. 
The blood in its regurgitation toward the heart finds its way into these sinuses, and 
so shuts down the valve-flaps. The pulmonary valves are situated behind the junc- 
tion of the left third costal cartilage with the sternum. 
The Left Auricle is rather smaller than the right; its walls thicker, measuring 
about one line and a half; it consists, like the right, of two parts, a principal cavity 
or sinus and an appendix auriculce. 
The sinus is cuboidal in form, and concealed in front by the pulmonary artery 
and aorta; internally it is separated from the right auricle by the septum auricula- 
rum ; behind it receives on each side the pulmonary veins, being free in the rest of 
its extent. 
The appendix auriculce is somewhat constricted at its junction with the auricle; 
it is longer, narrower, and more curved than that of the right side, and its margins 
more deeply indented, presenting a kind of foliated appearance. Its direction is for- 
ward and toward the right side, overlapping the root of the pulmonary artery. 
In order to examine its interior a horizontal incision should be made along the attached 
border of the auricle to the ventricle, and from the middle of this a second incision should be 
carried upward. 
The following parts then present themselves for examination: 
The openings of the four pulmonary veins. 
Auriculo-ventricular opening. 
Musculi pectinati. 
The pulmonary veins, four in number, open, two into the right and two into the 
left side of the auricle. The two left veins frequently terminate by a common open- 
ing. They are not provided with valves. 
The auriculo-ventricular opening is the large oval aperture of communication 
between the auricle and ventricle. It is rather smaller than the corresponding 
opening on the opposite side. (See note 2, p. 909.) 
The wwsewZt pectinati are fewer in number and smaller than on the right side; 
they are confined to the inner surface of the appendix. 
On the inner surface of the septum auricularum may be seen a lunated impres- 
sion, bounded below by a crescentic ridge, the concavity of which is turned upward. 
The depression is just above the fossa ovalis in the right auricle. 
described as fibro-cartilaginous in structure. At my request, Mr. Le Cronier Lancaster, demonstrator 
of physiology at St. George's Hospital, has investigated this subject, and reports that the " corpora 
Arantii" appear to consist of bundles of interlacing connective-tissue fibres with branched connec- 
tive-tissue cells and some few elastic fibres. Occasionally a rounded cell, with indistinct capsule, 
resembling a cartilage-cell, was seen, but there were not many of them. At the free edge of the 
corpus the structure is denser, there being a larger proportion of fibres to cells than in the central 
portion. He thinks the structure of the corpus should be put down as fibrous, and not fibro-carti- 
laginous. 912 
THE THORAX. 
The Left Ventricle is longer and more conical in shape than the right ventricle. 
It forms a small part of the left side of the anterior surface of the heart and a con- 
siderable part of its posterior surface. It also forms the apex of the heart by its 
projection beyond the right ventricle. Its walls are much thicker than those of the 
right side, the proportion being as 3 to 1. They are also thickest in the broadest 
part of the ventricle, becoming gradually thinner toward the base, and also toward 
the apex, which is the thinnest part. 
Its cavity should be opened by making an incision through its anterior wall along the left 
side of the ventricular septum, and carrying it round the apex and along its posterior surface to 
the auriculo-ventricular opening. 
The following parts present themselves for examination: 
Openings. 
Auriculo-ventricular. 
Aortic. 
Valves. 
Mitral. 
Semilunar. 
Chordae tendineae. 
Columnae carneae. 
The auriculo-ventricular opening is placed below and to the left of the aortic 
orifice, in the third intercostal space to the left of the sternum. It is a little smaller 
than the corresponding aperture of the opposite side, and, like it, is broader in the 
transverse than in the antero-posterior diameter. It is surrounded by a dense fibrous 
ring covered by the lining membrane of the heart and guarded by the mitral valve. 
The aortic opening is a small circular aperture in front and to the right side of 
the auriculo-ventricular, from which it is separated by one of the segments of the 
mitral valve. Its orifice is guarded by the semilunar valves. Its position corre- 
sponds to the left half of the sternum on a line with the lower border of the third 
costal cartilage. 
The mitral valve is attached to the circumference of the auriculo-ventricular ori- 
fice in the same way that the tricuspid valve is on the opposite side. It is formed by 
a duplicature of the lining membrane, strengthened by fibrous tissue, and contains a 
few muscular fibres. It is larger in size, thicker, and altogether stronger than the 
tricuspid, and consists of two segments of unequal size. The larger segment is 
placed in front, between the auriculo-ventricular and aortic orifices, and is said to 
prevent the filling of the aorta during the distension of the ventricle. Two smaller 
segments are usually found at the angle of junction of the larger. The mitral 
valve-flaps are furnished with chordae tendinese, the mode of attachment of which 
is precisely similar to that of those on the right side, but they are thicker, stronger, 
and less numerous. The mitral valve lies in the third intercostal space, about an 
inch from the left border of the sternum. 
The semilunar valves surround the orifice of the aorta; two are posterior (right 
and left) and one anterior: they are similar in structure and in their mode of 
attachment to those of the pulmonary artery. They are, however, larger, thicker, 
and stronger than those of the right side; the lunulae are more distinct, and the 
corpora Arantii larger and more prominent, Between each valve and the cylinder 
of the aorta is a deep depression, the sinus aortici (sinuses of Valsalva); they are 
larger than those at the root of the pulmonary artery. The aortic valves lie behind 
the left border of the sternum, close to the lower margin of the third costal cartilage. 
[For the positions of the valves, and the best places in which to auscult them, 
see Holden's Landmarks, § 43.] 
The columnce carnece admit of a subdivision into three sets, like those upon the 
right side, but they are smaller, more numerous, and present a dense interlacement, 
especially at the apex and upon the posterior wall. Those attached by one extremity 
only, the musculi papillares. are two in number, being connected one to the anterior, 
the other to the posterior wall; they are of large size, and terminate by free rounded 
extremities from which the chordae tendineae arise. 
The endocardium is a thin membrane which lines the internal surface of the 
heart; it assists in forming the valves by its reduplications, and is continuous with 
the lining membrane of the great blood-vessels. It is a smooth, transparent mem- THE HEART. 
913 
brane, giving to the inner surface of the heart its glistening appearance. It is more 
opaque on the left than on the right side of the heart, thicker in the auricles than 
in the ventricles, and thickest in the left auricle. It is thin on the musculi pecti- 
nati and on the col inn rise carnese, but thicker on the smooth part of the auricular 
and ventricular walls and on the tips of the musculi papillares. 
Structure.-The heart consists of muscular fibres and of fibrous rings which 
serve for their attachment. 
The fibrous rings surround the auriculo-ventricular and arterial orifices: they 
are stronger upon the left than on the right side of the heart. The auriculo-ven- 
tricular rings serve for the attachment of the muscular fibres of the auricles and 
ventricles, and also for the mitral and tricuspid valves; the ring on the left side 
is closely connected by its right margin with the aortic arterial ring. Between 
these and the auriculo-ventricular ring is a mass of fibrous tissue, and, in some 
of the larger animals, as the ox and elephant, a nodule of bone. 
The fibrous rings surrounding the arterial orifices serve for the attachment of the 
great vessels and semilunar valves. Each ring receives by its ventricular margin 
the attachment of the muscular fibres of the ventricles; its opposite margin presents 
three deep semicircular notches, within which the middle coat of the artery (which 
presents three convex semicircular segments) is firmly fixed, the attachment of the 
artery to its fibrous ring being strengthened by the thin cellular coat and serous 
membrane externally and by the endocardium within. It is opposite the margins 
of these semicircular notches, in the arterial rings, that the endocardium, by its 
reduplication, forms the semilunai' valves, the fibrous structure of the ring being 
continued into each of the segments of the valve at this part. The middle coat of 
the artery in this situation is thin, and the sides of the vessel are dilated to form the 
sinuses of Valsalva. 
The muscular structure of the heart consists of bands of fibres which present 
an exceedingly intricate interlacement. They are of a deep-red color and marked 
with transverse striae (p. 66). 
The muscular fibres of the heart admit of a subdivision into two kinds-those 
of the auricles and those of the ventricles, which are quite independent of one 
another. 
Fibres of the Auricles.-These are disposed in two layers-a superficial layer 
common to both cavities, and a. deep layer proper to each. The superficial fibres 
are more distinct on the anterior surface of the auricles, across the bases of which 
they run in a transverse direction, forming a thin but incomplete layer. Some of 
these fibres pass into the septum auricularum. The internal or deep fibres proper to 
each auricle consist of two sets, looped and annular fibres. The looped fibres pass 
upward over each auricle, being attached by two extremities to the corresponding 
auriculo-ventricular rings in front and behind. The annular fibres surround the 
whole extent of the appendices auricularum, and are continued upon the walls of 
the venae cavae and coronary sinus on the right side, and upon the pulmonary veins 
on the left side at their connection with the heart. In the appendices they inter- 
lace with the longitudinal fibres. 
The fibres of the ventricles are arranged in numerous layers, of which Pettigrew1 
describes seven. Other anatomists have regarded them differently, and indeed there 
must be some uncertainty on the subject, for the layers are not independent of each 
other, but their fibres are interlaced to a considerable extent. And it has been 
observed that as Pettigrew's observations were made chiefly on the hearts of the 
lower animals, they may not apply exactly to man. Yet as his description has been 
received by some of the best anatomists and is supported by a large series of prep- 
arations, it seems best to adopt it. 
The general result of these investigations may be very briefly stated as follows: 
In the left ventricle the fibres of the first or most external layer are continuous with 
those of the seventh or most internal, those of the second with the sixth, and those 
of the third with the fifth, while the fourth or central layer appears to be single. 
1 Phil. Trans., 1864. 914 
THE THORAX. 
The general direction of the fibres of the external layer is nearly vertical, but 
inclining somewhat from the left to right as they run downward; the direction of 
the fibres of the internal layer is just the reverse, nearly vertical, but running 
upward from left to right; those of the second layer run more obliquely downward 
from left to right, and those of the sixth with a corresponding obliquity in the 
reversed direction. The obliquity of the fibres of the third layer is greater; in 
fact, they approach the horizontal, as do those of the fifth in the reversed direction, 
while the fibres of the fourth layer run pretty nearly horizontal. The thickness of 
the layers increases from without inward, so that the fourth layer, which is the mid- 
dle in order of sequence, lies nearer the outer than the inner surface of the ventric- 
ular wall. The fibres of the external or superficial layer arise, as a rule, from the 
auriculo-ventricular rings and from the fibrous rings surrounding the aorta, but a 
few of them are continued beneath the rings into the columnae carneae.1 They 
curve round at the apex in a spiral, which forms the whorl or vortex, those from the 
anterior surface of the heart curving round to enter the apex posteriorly, and vice 
versd. From the apex they are traced up into the seventh layer, which is much 
thicker, and from which the musculi papillares and columnae carneae are chiefly 
formed. The apex of the heart is made up exclusively of the fibres of this first 
layer (or first and seventh), so that when it is removed the ventricle is opened. And 
the successive layers terminate farther and farther from the apex-an arrangement 
which has led to their fibres being described as shorter; which Pettigrew doubts, 
attributing the shortness of the layers to the different direction of the fibres, not to 
any difference in length in the individual fibres. Since the deeper layers do not 
descend to the apex, this is the thinnest part of the ventricle, measuring only one- 
eighth of an inch in thickness even in the heart of an ox. 
The fibres of the deeper layers are not connected with the auriculo-ventricular 
rings, but pass below them, each layer terminating a little below the more superficial 
layer which wraps round it, though the difference in this respect is not so great as in 
their depth toward the apex. 
The fibres of the first layer pass across the septum from one ventricle to the other 
-an arrangement particularly well seen at the back of the heart, where there is a set 
of transverse fibres described by Pettigrew as the " hinge-like fibres " of the back 
of the heart; and the three subjacent layers also take part in the formation of both 
ventricles; but when the fourth layer is removed the two ventricles are entirely 
severed from each other posteriorly. The septum is formed of the fibres of both 
ventricles applied to each other. 
The general arrangement of the fibres of the right ventricle is the same as that 
of the left, but the external fibres do not pass in to be continuous with the internal 
at a single point-the apex-but all along the anterior coronary groove. Its fibres 
are more delicate than those of the left, and it is regarded by Pettigrew as formed 
out of the left ventricle by a kind of reflection inward of the wall of the single cav- 
ity of which the ventricles consist at one period of foetal life. (See p. 124.) He points 
out that the heart at that period may be supposed to be represented by an open tube 
formed of spiral fibres. If, now, a portion of this tube or cylinder were pushed 
down to meet the opposite wall, to which the fibres of the reflected portion adhere 
and with which they coalesce, there would be formed an offset from the common 
ventricular cavity, formed partly of common and partly of special fibres, as is the 
case in the heart. At this early period the outer layers are not formed and the 
apex is still unclosed. Their formation closes in the apex and completes the walls 
of the ventricles. If this is the case, the septum must be formed of two elements 
or sets of fibres-one proper to the original single ventricle, and therefore in after- 
life proper to the left ventricle; the other set formed from the reflected or redupli- 
cated fibres which now form the right ventricle.2 To these of course the fibres which 
1 " It is a great mistake to imagine that all the fibres of the ventricles arise from the auriculo- 
ventricular tendinous rings, the fact being that, with the exception of the fibres of the first and 
seventh layers, they are continuous beneath them."-Pettigrew, op. cit., p. 456, note. 
2 If the general idea of this is not at once obvious, it will become so by taking a roll of paper, THE HEART. 
915 
cross over from one ventricle to the other may be added. Pettigrew regards the 
portion of the septum -which belongs to the left ventricle as twice that which belongs 
to the right. (For many interesting particulars with regard to the arrangement of 
the fibres and the shape of the cavities the reader must be referred to the original 
paper.) 
Vessels and Nerves.-The arteries supplying the heart are the left or anterior 
and right or posterior coronary (p. 507). 
The veins accompany the arteries, and terminate in the right auricle. They are 
the great cardiac vein, the anterior, middle, and posterior cardiac veins, and the 
venae cordis minimae fence Thebesii} (pp. 636, 637). 
The lymphatics terminate in the thoracic and right lymphatic ducts. 
The nerves are derived from the cardiac plexuses, which are formed partly from 
the cranial nerves and partly from the sympathetic. They are freely distributed 
both on the surface and in the substance of the heart, the separate filaments being 
furnished with small ganglia.1 
The chief peculiarities in the Heart of the fcetus are the direct communication 
between the two auricles through the foramen ovale and the large size of the 
Eustachian valve. There are also several minor peculiarities. Thus, the position 
of the heart is vertical until the fourth month, when it commences to assume an 
oblique direction. Its size is also very considerable as compared with the body, 
the proportion at the second month being 1 to 50, at birth it is as 1 to 120, whilst 
in the adult the average is about 1 to 160. At an early period of foetal life the 
auricular portion of the heart is larger than the ventricular, the right auricle being 
more capacious than the left; but toward birth the ventricular portion becomes the 
larger. The thickness of both ventricles is at first about equal, but toward birth 
the left becomes much the thicker of the two. 
The foramen ovale is situated at the lower and back part of the septum auricu- 
larum, forming a communication between the auricles. It remains as a free oval 
opening from the time of the formation of the auricular septum (about the eighth 
week) until the middle period of foetal life. About this period a fold grows up 
from the posterior wall of the auricle to the left of the foramen ovale, and advances 
over the opening, so as to form a sort of valve, which allows the blood to pass only 
from the right to the left auricle, and not in the opposite direction. 
The Eustachian valve is developed from the anterior border of the inferior vena 
cava at its entrance into the auricle. It is directed upward on the left side of the 
opening of this vein, and serves to direct the blood from the inferior vena cava 
through the foramen ovale into the left auricle. 
The peculiarities in the Arterial System of the foetus are the communication 
between the pulmonary artery and descending part of the arch of the aorta by 
means of the ductus arteriosus, and the communication between the internal iliac 
arteries and the placenta by means of the umbilical arteries. 
The ductus arteriosus is a short tube about half an inch in length at birth and 
of the diameter of a goose-quill. In the early condition it forms the continuation 
of the pulmonary artery, and opens into the arch of the aorta just below the origin 
of the left subclavian artery, and so conducts the chief part of the blood from the 
right ventricle into the descending aorta. When the branches of the pulmonary 
artery have become larger relatively to the ductus arteriosus, the latter is chiefly 
Peculiarities in the Vascular System of the Fcetus. 
calling one side of it the posterior and the other the anterior, and bending it at the right side of its 
middle till the anterior touches the posterior surface. The larger part to the left of the middle line 
represents the left ventricle, the smaller the right, and the double fold in the middle the septum; 
then if the reflected parts where they touch are gummed to each other this will represent the coales- 
cence of the septum with the outer wall, whereby the right ventricle becomes a separate tube from 
the left. The lower openings of these two tubes are closed in by the growth of the external layers. 
1 For full and accurate descriptions of the nerves and ganglia of the heart the student is referred 
to Dr. R. Lee's papers on the subject. 916 
THE THORAX. 
connected to the left pulmonary artery, and the fibrous cord, which is all that 
remains of the ductus arteriosus in later life, will be found to be attached to the 
root of that vessel. 
The umbilical or hypogastric arteries arise from the internal iliacs. Ascending 
along the sides of the bladder to its fundus, they pass out of the abdomen at the 
umbilicus, and are continued along the umbilical cord to the placenta, coiling round 
the umbilical vein. They return to the placenta the blood which has circulated in 
the system of the foetus. 
The peculiarity in the Venous System of the foetus is the communication estab- 
lished between the placenta and the liver and portal vein through the umbilical vein, 
and with the inferior vena cava by the ductus venosus. 
Foetal Circulation. 
The blood destined for the nutrition of the foetus is carried from the placenta to 
the foetus along the umbilical cord by the umbilical vein. The umbilical vein 
enters the abdomen at the umbilicus, and passes upward along the free margin of 
the suspensory ligament of the liver to the under surface of that organ, where it 
gives off two or three branches to the left lobe, one of which is of large size; and 
others to the lobus quadratus and lobulus Spigelii. At the transverse fissure it 
divides into two branches: of these, the larger is joined by the portal vein, and 
enters the right lobe; the smaller branch continues onward, under the name of the 
ductus venosus, and joins the left hepatic vein at the point of junction of that ves- 
sel with the inferior vena cava. The blood, therefore, which traverses the umbilical 
vein reaches the inferior vena cava in three different ways. The greater quantity 
circulates through the liver with the portal venous blood before entering the vena 
cava by the hepatic veins; some enters the liver directly, and is also returned to 
the inferior cava by the hepatic veins; the smaller quantity passes directly into 
the vena cava by the junction of the ductus venosus with the left hepatic vein. 
In the inferior cava the blood carried by the ductus venosus and hepatic veins 
becomes mixed with that returning from the lower extremities and viscera of the 
abdomen. It enters the right auricle, and, guided by the Eustachian valve, passes 
through the foramen ovale into the left auricle, where it becomes mixed with a 
small quantity of blood returned from the lungs by the pulmonary veins. From 
the left auricle it passes into the left ventricle, and from the left ventricle into the 
aorta, by means of which it is distributed almost entirely to the head and upper 
extremities, a small quantity being probably carried into the descending aorta. 
From the head and upper extremities the blood is returned by the branches of the 
superior vena cava to the right auricle, where it becomes mixed with a small por- 
tion of the blood from the inferior cava. From the right auricle it descends over 
the Eustachian valve into the right ventricle, and from the right ventricle passes into 
the pulmonary artery. The lungs of the foetus being solid and almost impervious, 
only a small quantity of the blood of the pulmonary artery is distributed to them 
by the right and left pulmonary arteries, which is returned by the pulmonary 
veins to the left auricle: the greater part passes through the ductus arteriosus 
into the commencement of the descending aorta, where it becomes mixed with a 
small quantity of blood transmitted by the left ventricle into the aorta. Along 
this vessel it descends to supply the lower extremities and viscera of the abdomen 
and pelvis, the chief portion being, however, conveyed by the umbilical arteries to 
the placenta. 
From the preceding account of the circulation of the blood in the foetus it will 
be seen- 
1. That the placenta serves the double purpose of a respiratory and nutritive 
organ, receiving the venous blood from the foetus and returning it again reoxygen- 
ated and charged with additional nutritive material. 
2. That nearly the whole of the blood of the umbilical vein traverses the liver 
before entering the inferior cava [and the liver is the only organ in the foetus that THE HEART. 
917 
receives pure arterial blood] ; hence the large size of this organ, especially at an 
early period of foetal life. 
3. That the right auricle is the point of meeting of a double current, the blood 
in the inferior cava being guided by the Eustachian valve into the left auricle, 
Fig. 605. 
Ductus 
Anteriosus 
Internal Iliac 
' Artery 
Plan of the Foetal Circulation. In this plan the figured arrows represent the kind of blood, as well as the 
direction which it takes in the vessels. Thus, arterial blood is figured >»; venous blood, 
mixed (arterial and venous) blood, 
[The red and blue colors only indicate artery and vein, and not the character of the blood contained in them.] 
whilst that in the superior cava descends into the right ventricle. At an early 
period of foetal life it is highly probable that the two streams are quite distinct, for 
the inferior cava opens almost directly into the left auricle, and the Eustachian 918 
THE THORAX. 
valve would exclude the current along the vein from entering the right ventricle. 
At a later period, as the separation between the two auricles becomes more distinct, 
it seems probable that some mixture of the two streams must take place. 
4. The blood carried from the placenta to the foetus by the umbilical vein, mixed 
with the blood from the inferior cava, passes almost directly to the arch of the aorta, 
and is distributed by the branches of that vessel to the head and upper extremities; 
hence the large size and perfect development of those parts at birth. 
5. The blood contained in the descending aorta, chiefly derived from that which 
has already circulated through the head and limbs, together with a small quantity 
from the left ventricle, is distributed to the lower extremities; hence the small size 
and imperfect development of these parts at birth. 
At birth, when respiration is established, an increased amount of blood from the 
pulmonary artery passes through the lungs, which now perform their office as respi- 
ratory organs, and at the same time the placental circulation is cut off. The fora- 
men ovale becomes gradually closed in by about the tenth day after birth; the 
valvular fold above mentioned becomes adherent to the margins of the foramen for 
the greater part of its circumference, but above a slit-like opening is left between 
the two auricles, which sometimes remains persistent. 
The ductus arteriosus begins to contract immediately after respiration is estab- 
lished, becomes completely closed from the fourth to the tenth day, and ultimately 
degenerates into an impervious cord which serves to connect the left pulmonary 
artery to the concavity of the arch of the aorta. 
Of the umbilical or hypogastric arteries, the portion between the internal iliac 
artery and the superior vesical branch to the bladder remains pervious, though 
greatly shrunken in size in proportion to its lessened function; while the part 
between the fundus of the bladder and the umbilicus becomes obliterated between 
the second and fifth days after birth, and persists as a fibrous cord projecting into 
the peritoneal sac, so as to form the two fossae of the peritoneum spoken of in the 
section on the Surgical Anatomy of Direct Inguinal Hernia. 
The umbilical vein and ductus venosus become completely obliterated between 
the second and fifth days after birth, and ultimately dwindle to fibrous cords, the 
former becoming the round ligament of the liver, the latter the fibrous cord which 
in the adult may be traced along the fissure of the ductus venosus. 
[Dr. J. Collins Warren, in a monograph of great ability entitled The Healing 
of Arteries after Ligature in Man and Animals (New York, 1886), has most care- 
fully investigated the mode of closure of the foetal vessels, and the student is referred 
to his book for fuller information.] 
Changes in the Vascular System at Birth. Organs of Voice and Respiration. 
THE LARYNX. 
THE Larynx is the organ of voice, placed at the upper part of the air-passage. 
It is situated between the trachea and base of the tongue, at the upper and fore 
part of the neck, where it forms a considerable projection in the middle line. On 
each side of it lie the great vessels of the neck; behind, it forms part of the bound- 
ary of the pharynx, and is covered by the mucous membrane lining that cavity. 
The larynx is narrow and cylindrical below, but broad above, where it presents 
the form of a triangular box flattened behind and at the sides, whilst in front it is 
bounded by a prominent vertical ridge. It is composed of cartilages which are 
connected together by ligaments and moved by numerous muscles: the interior is 
lined by mucous membrane and supplied with vessels and nerves. 
The Cartilages of the larynx are nine in number, three single and three pairs: 
Thyroid. 
Cricoid. 
Epiglottis. 
Two Arytenoid. 
Two Cornicula Laryngis. 
Two Cuneiform. 
The Thyroid (fupeoQ a shield) is the largest cartilage of the larynx. It con- 
sists of two lateral lamellae or alae united at an acute angle in front, forming a 
vertical projection in the middle line, which is 
prominent above and called the pomum Adami. 
This projection is subcutaneous, more distinct in 
the male than in the female, and occasionally sep- 
arated from the integument by a bursa mucosa. 
Each lamella is quadrilateral in form. Its 
outer surface presents an oblique ridge, which 
passes downward and forward from a tubercle sit- 
uated near the root of the superior cornu. This 
ridge gives attachment to the Sterno-thyroid and 
Thyro-hyoid muscles; the portion of cartilage in- 
cluded between it and the posterior border to part 
of the Inferior constrictor muscle. 
The inner surface of each ala is smooth, con- 
cave, and covered by mucous membrane above 
and behind; but in front, in the receding angle 
formed by their junction, are attached the epi- 
glottis, the true and false vocal chords, the Thyro- 
arytenoid and Thyro-epiglottidean muscles. 
The upper border of the thyroid cartilage is 
deeply notched in the middle line immediately 
above the pomum Adami, whilst on either side 
it is slightly concave. This border gives attach- 
ment throughout its whole extent to the thyro- 
hyoid membrane. 
The lower border is connected to the cricoid 
cartilage, in the median line, by the crico-thyroid membrane, and on each side by 
the Crico-thyroid muscle. . 
The posterior borders, thick and rounded, terminate above in the superior cor- 
nua, and below in the inferior cornua. The two superior cornua are long and 
Fig. 606. 
Side View of the Thyroid and Cricoid 
Cartilages. 
919 920 
ORGANS OF VOICE AND RESPIRATION. 
narrow, directed upward, backward, and inward, and terminate in a conical extrem- 
ity which gives attachment to the thyro-hyoid ligament. The two inferior cornua 
are short and thick; they pass downward, with a slight inclination forward and 
inward, and present on their inner surfaces a small oval articular facet for articula- 
tion with the side of the cricoid cartilage. The posterior border receives the inser- 
tion of the Stylo-pharyngeus and Palato-pharyngeus muscles on each side. 
The Cricoid Cartilage is so called 
from its resemblance to a signet- 
ring (xpbtos, a ring). It is smaller 
but thicker and stronger than the thy- 
roid cartilage, and forms the lower and 
back part of the cavity of the larynx. 
Its anterior half is narrow, con- 
vex, affording attachment in front 
and at the sides to the Crico-thyroid 
muscles, and behind these to part of 
the Inferior constrictor. 
Its posterior half is very broad, 
both from side to side and from above 
downward ; it presents in the middle 
line a vertical ridge for the attach- 
ment of the longitudinal fibres of 
the oesophagus, and on either side a 
broad depression for the Crico-arytse- 
noideus posticus muscle. 
At the point of junction of the 
two halves of the cartilage on either 
side is a small round elevation for 
articulation with the inferior cornu 
of the thyroid cartilage. 
The lower border of the cricoid 
cartilage is horizontal, and connected 
to the upper ring of the trachea by 
fibrous membrane. 
Its upper border is directed ob- 
liquely upward and backward, owing 
to the great depth of its posterior 
surface. It gives attachment in front 
to the crico-thyroid membrane; at the 
sides to part of the same membrane 
and to the lateral Crico-arytenoid 
muscle ; behind, the highest point of 
the upper border is surmounted on 
each side by a smooth oval surface 
for articulation with the arytenoid 
cartilage. Between the articular 
surfaces is a slight notch for the 
attachment of part of the Arytenoideus muscle. 
The inner surface of the cricoid cartilage is smooth and lined by mucous 
membrane. 
The Arytenoid Cartilages are so called from the resemblance they bear, when 
approximated, to the mouth of a pitcher (apbraioa, a pitcher). They are two in 
number, and situated at the upper border of the cricoid cartilage at the back of the 
larynx. Each cartilage is pyramidal in form and presents for examination three 
surfaces, a base, and an apex. , 
The posterior surface is triangular, smooth, concave, and gives attachment to the 
Arytenoid muscle. 
Fro. G07. 
EPIGLOTTIS 
THYROID 
tfii.netfor>n 
ComieuTcb la/ryngit 
ARYTENOID 
-Jtoatefrlo't' 
Surface 
Jhisertiotv of 
CRfCO-AR YTA-NQf D 
POST ICLBET LATERALIS 
Arytenoid Cart9.**. lose 
CRICOI D 
Articular facet 
Jo* AryU-ncid Cartilage 
Articular 
far Infer. Ccmu. 
of Thyroid C. 
The Cartilages of the Larynx, posterior view. THE LARYNX. 
921 
The anterior surface, somewhat convex and rough, gives attachment to the 
Thyro-arytenoid muscle and to the false vocal chord. 
The internal surface is narrow, smooth, and flattened, covered by mucous mem- 
brane, and lies almost in apposition with the cartilage of the opposite side. 
The base of each cartilage is broad, and presents a concave smooth surface for 
articulation with the cricoid cartilage. Of its three angles, the external is short, 
rounded, and prominent, receiving the insertion of the Posterior and Lateral crico- 
arytenoid muscles. The anterior angle, also prominent but more pointed, gives 
attachment to the true vocal chord. 
The apex of each cartilage is pointed, curved backward and inward, and sur- 
mounted by a small conical-shaped, cartilaginous nodule, the corniculum laryngis. 
The Cornicula Laryngis (cartilages of Santorini} are two small conical nodules, 
consisting of yellow fibro-cartilage, which articulate with the summit of the aryte- 
noid cartilages and serve to prolong them backward and inward. To them are 
attached the aryteno-epiglottidean folds. They are sometimes united to the aryte- 
noid cartilages. 
The Cuneiform Cartilages (cartilages of Wrisberg} are two small, elongated, 
cartilaginous bodies, placed one on each side in the fold of mucous membrane which 
extends from the apex of the arytenoid cartilage to the side of the epiglottis (aryte- 
no-epiglottidean fold}; they give rise to small whitish elevations on the inner surface 
of the mucous membrane just in front of the arytenoid cartilages. 
The Epiglottis is a thin lamella of fibro-cartilage, of a yellowish color, shaped like 
a leaf, and placed behind the tongue in front of the superior opening of the larynx. 
[In a fair proportion of persons the tip of the epiglottis can be seen when the tongue 
is well protruded.] During respiration its direction is vertically upward, its free 
extremity curving forward toward the base of the tongue; but when the larynx is 
drawn up beneath the base of the tongue during deglutition, it is carried downward 
and backward, so as to completely close the opening of the larynx. Its free extrem- 
ity is broad and rounded; its attached end is long and narrow, and connected to the 
receding angle between the two aim of the thyroid cartilage, just below the median 
notch, by a long, narrow, ligamentous band, the thyro-epiglottic ligament. It is also 
connected to the posterior surface of the body of the hyoid bone by an elastic liga- 
mentous band, the hyo-epiglottic ligament. 
Its anterior or lingual surface is curved forward toward the tongue, and covered 
at its upper part by mucous membrane, which is reflected on to the sides and base 
of the organ, forming a median and two lateral folds, the glosso-epiglottidean liga- 
ments. 
Its posterior or laryngeal surface is smooth, concave from side to side, convex 
from above downward, and covered by mucous membrane; when this is removed 
the surface of the cartilage is seen to be studded with a number of small mucous 
glands which are lodged in little pits upon its surface. To its sides the aryteno- 
epiglottidean folds are attached. 
Structure.-The epiglottis, cuneiform cartilages, and cornicula laryngis are com- 
posed of yellow fibro-cartilage which shows little tendency to ossification; but the 
other cartilages resemble in structure the costal cartilages, becoming more or less 
ossified in old age. 
Ligaments.-The ligaments of the larynx are extrinsic-i. e. those connecting 
the thyroid cartilage and epiglottis with the hyoid bone-and intrinsic-those which 
connect the several cartilaginous segments to each other. 
The ligaments connecting the thyroid cartilage with the hyoid bone are three in 
number-the thyro-hyoid membrane and the two lateral thyro-hyoid ligaments. 
That connecting the epiglottis with the hyoid bone is the hyo-epiglottic. 
The thyro-hyoid membrane is a broad, fibro-elastic, membranous layer attached 
below to the upper border of the thyroid cartilage and above to the upper border 
of the hvoid bone, passing behind the posterior surface and being separated from it 
by a synovial bursa. It is thicker in the middle line than at either side, in which 
situation it is pierced by the superior laryngeal vessels and nerve. 922 
ORGANS OF VOICE AND RESPIRATION. 
The two lateral thyro-hyoid ligaments are rounded elastic cords which pass 
between the superior cornua of the thyroid cartilage and the extremities of the 
greater cornua of the hyoid bone. A small cartilaginous nodule (partilago triticea), 
sometimes bony, is frequently found in each. 
The hyo-epiglottic ligament is an elastic fibrous band which extends from the 
anterior surface of the epiglottis, near its apex, to the upper border of the body of 
the hyoid bone. 
The ligaments connecting the thyroid cartilage to the cricoid are also three in 
number-the crico-thyroid membrane and the capsular ligaments and synovial 
membranes. 
The crico-thyroid membrane [Fig. 614, p. 928] is composed mainly of yellow 
elastic tissue. It is of triangular shape; thick in front, where it connects together 
the contiguous margins of the thyroid and cricoid cartilages; thinner at each side, 
where it extends from the superior border of the cricoid cartilage to the inferior 
margin of the true vocal chords, with which it is closely united in front. 
The anterior portion of the crico-thyroid membrane is convex, concealed on 
each side by the Crico-thyroid 
muscle, subcutaneous in the 
middle line, and crossed hor- 
izontally by a small anastomotic 
arterial arch formed by the junc- 
tion of the two crico-thyroid ar- 
teries. The lateral portions are 
lined internally by mucous mem- 
brane and covered by the lateral 
Crico-arytenoid and Thyro-ary- 
tenoid muscles. 
[The hyoid bone, pomum 
Adami, superior and inferior 
borders of tlie thyroid cartilage, 
the cricoid cartilage, and the crico- 
thyroid membrane, are all easily 
felt, and are of the greatest im- 
portance in operations in this lo- 
cality.] 
A capsular ligament encloses 
the articulation of the inferior 
cornu of the thyroid with the cricoid cartilage on each side. The articulation is 
lined by synovial membrane. 
The ligaments connecting the arytenoid cartilages to the cricoid are two thin and 
loose capsular ligaments connecting together the articulating surfaces, lined inter- 
nally by synovial membrane, and strengthened behind by a strong posterior crico- 
arytenoid ligament which extends from the cricoid to the inner and back part of the 
base of the arytenoid cartilage. 
The ligaments of the epiglottis are the thyro-epiglottic, the hyo-epiglottic (al- 
ready described), and the three glosso-epiglottic folds of mucous membrane which 
connect the epiglottis to the sides and base of the tongue [already described 
above]. 
The thyro-epiglottic ligament is a long, slender, elastic cord which connects the 
apex of the epiglottis with the receding angle of the thyroid cartilage immediately 
beneath the median notch, above the attachment of the vocal chords. 
Interior of the Larynx.-The superior aperture of the larynx (Fig. 608) is a 
triangular or cordiform opening, wide in front, narrow behind, and sloping obliquely 
downward and backward. It is bounded in front by the epiglottis; behind by the 
apices of the arytenoid cartilages and the cornicula laryngis; and laterally by a fold 
of mucous membrane enclosing ligamentous and muscular fibres stretched between 
the sides of the epiglottis and the apex of the arytenoid cartilages: these are the 
Fig. 608. 
Arytenoid. <:a' ' 
Ttinta, alottld-LS 
local 
TeuLncte between 
themj 
Base '£fi' Ton^c 
The Larynx and Adjacent Parts, seen from above. THE LARYNX. 
923 
aryteno-epiglottidean folds, on the margins of which the cuneiform cartilages form 
a more or less distinct whitish prominence. 
The cavity of the larynx extends from the aperture behind the epiglottis to the 
lower border of the cricoid cartilage. It is divided into two parts by the projection 
inward of the true vocal chords and the Thyro-arytenoid muscles; between the two 
chords is a long and narrow triangular fissure or chink, the glottis, or rima glottidis. 
The portion of the cavity of the larynx above the glottis is broad and triangular in 
shape, and corresponds to the interval between the alae of the thyroid cartilage; 
the portion below the glottis is at first of an elliptical, and lower down of a cir- 
cular form. 
The rima glottidis is the narrow fissure or chink between the inferior or true 
vocal chords. It is the narrowest part of the cavity of the larynx, and corresponds 
Fig. 609. 
[Fig. 610. 
(jlosso-epiqlo? 
'foltb 
Laryngeal Image during Phonation.] 
calt£ 
[Fig. 611. 
foal CoriLsfi 
Ven t~ncler 
\aijtenoiiL 
l miLscte. 
'tri co-thyroid ■ 
nienib £■ 
Laryngoscopic Diagram showing the Vocal Chords 
widely drawn apart, and the position of the 
various parts above and below the glottis dur- 
ing quiet breathing: ge, glosso-epiglottic fold s; 
u, upper surface of epiglottis; I, hp or arch of 
epiglottis; c, protuberance of epiglottis; 
tricle of the larynx; ae, ary-epiglottic fold; 
cIF, cartilage of Wrisberg; cS, cartilage of San- 
torini ; com, arytenoid commissure; vc, vocal 
chord; vb, ventricular band; pv, processus vo- 
calis; cr, cricoid cartilage; t, rings of trachea 
(from Mackenzie).] 
Vertical Section of the Larynx and Upper Part 
of the Trachea. 
to the lower level of the arytenoid cartilages. Its length in the male measures 
rather less than an inch, its breadth, when dilated, varying at its widest part from 
a third to half an inch. In the female these measurements are less by two or three 
lines. The form of the glottis varies [Figs. 610 and 611]. In its half-closed con- 
dition it is a narrow fissure a little enlarged and rounded behind. In quiet breath- 
ing it is widely open, somewhat triangular, the base of the triangle directed back- 
ward and corresponding to the space between the separated arytenoid cartilages. In 
forcible expiration it is smaller than during inspiration. When sound is produced 
it is more narrowed, the margins of the arytenoid cartilages being brought into con- 
tact, and the edges of the true vocal chords approximated and made parallel, the 
degree of approximation and tension corresponding to the height of the note pro- 
duced.1 
The superior or false vocal chords-so called because they are not directly con- 
cerned in the production of the voice-are two folds of mucous membrane enclosing 
1 On the shape of the glottis in the various conditions of breathing and speaking, see Czermak on 
the Laryngoscope, translated for the New Sydenham Society. 924 
ORGANS OF VOICE AND RESPIRATION. 
a delicate narrow fibrous band, the superior thyro-arytenoid ligament. This liga- 
ment consists of a thin band of elastic tissue attached in front to the angle of the 
thyroid cartilage below the epiglottis, and behind to the anterior surface of the ary- 
tenoid cartilage. The lower border of this ligament, enclosed in mucous membrane, 
forms a free crescentic margin which constitutes the upper boundary of the ventricle 
of the larynx. 
The inferior or true vocal chords-so called from their being concerned in the 
production of sound-are two strong fibrous bands (inferior thyro-arytenoid liga- 
ments') covered on their surface by a thin layer of mucous membrane. Each liga- 
ment consists of a band of yellow* elastic tissue attached in front to the depression 
between the two alae of the thyroid cartilage, and behind to the anterior angle of 
the base of the arytenoid. Its lower border is continuous with the thin lateral part 
of the crico-thyroid membrane. Its uppei' border forms the lower boundary of the 
ventricle of the larynx. Externally, the Thyro-arytenoideus muscle lies parallel 
with it. It is covered internally by mucous membrane, which is extremely thin and 
closely adherent to its surface. [The superior or false vocal chords, since they take 
no part in voice, are better termed the "ventricular bands," as they form the upper 
margin of the opening into the ventricle.] 
The ventricle of the larynx is an oblong fossa situated between the superior and 
inferior vocal chords on each side and extending nearly their entire length. This 
fossa is bounded above by the free crescentic edge of the superior vocal chord; 
below* by the straight margin of the true vocal chord; externally by the correspond- 
ing Thyro-arytenoideus muscle. The anterior part of the ventricle leads up by a 
narrow opening into a caecal pouch of mucous membrane of variable size, called the 
laryngeal pouch. 
The sacculus laryngis, or laryngeal pouch, is a membranous sac placed between 
the superior vocal chord and the inner surface of the thyroid cartilage, occasionally 
extending as far as its upper border; it is conical in form and curved slightly back- 
ward, like a Phrygian cap. On the surface of its mucous membrane are the open- 
ings of sixty or seventy small follicular glands which are lodged in the submucous 
areolar tissue. This sac is enclosed in a fibrous capsule continuous below with the 
superior thyro-arytenoid ligament: its laryngeal surface is covered by the Aryteno- 
epiglottideus inferior muscle (Compressor sacculi laryngis, Hilton), whilst its exte- 
rior is covered by the Thyro-arytenoideus and Thyro-epiglottideus muscles. These 
muscles compress the sacculus laryngis, and discharge the secretion it contains upon 
the chordae vocales, the surfaces of which it is intended to lubricate. 
Muscles.-The intrinsic muscles of the larynx are eight in number, five of 
which are the muscles of the chordae vocales and rima glottidis; three are con- 
nected with the epiglottis. 
The five muscles of the chordae vocales and rima glottidis are the 
Crico-thyroid. 
Crico-arytaenoideus posticus. 
Crico-arytsenoideus lateralis. 
Arytoenoideus. 
Thyro-arytaenoideus. 
The Crico-thyroid is triangular in form, and situated at the fore part and side 
of the cricoid cartilage. It arises from the front and lateral part of the cricoid 
cartilage; its fibres diverge, passing obliquely upward and outward, to be inserted 
into the lower border of the thyroid cartilage and into the anterior border of the 
lower cornua. 
The inner borders of these two muscles are separated in the middle line by a tri- 
angular interval occupied by the crico-thyroid membrane. 
The Crico-arytcenoideus posticus arises from the broad depression occupying each 
lateral half of the posterioi' surface of the cricoid cartilage; its fibres pass upward 
and outward, converging to be inserted into the outer angle of the base of the ary- 
tenoid cartilage. The upper fibres are nearly horizontal, the middle oblique, and 
the lower almost vertical.1 
1 Dr. Merkel of Leipsic has described a muscular slip which occasionally extends between the THE LARYNX. 
925 
The Crico-arytcenoideus lateralis is smaller than the preceding, and of an oblong 
form. It arises from the upper border of the side of the cricoid cartilage, and, 
passing obliquely upward and backward, is inserted into the outer angle of the base 
of the arytenoid cartilage in front of the preceding muscle. 
The Arytoenoideus is a single muscle filling up the posterior concave surface of 
the arytenoid cartilages. It arises from the posterior surface and outer border of 
one arytenoid cartilage, and is inserted into the corresponding parts of the opposite 
cartilage. It consists of three planes of fibres, two oblique and one transverse. 
The oblique fibres, the most superficial, 
form two fasciculi which pass from the 
base of one cartilage to the apex of the 
opposite one. The transverse fibres, 
the deepest and most numerous, pass 
transversely across between the two 
cartilages; hence the Ary tenoideus was 
Fig. 612. 
Fig. 613. 
I ary ng is 
Articular Facet' 
for Inferior Cornu 
of Thyroid Cartil. 
Muscles of Larynx, side view, right ala of thyroid 
cartilage removed. 
Interior of the Larynx, seen from above (enlarged). 
formerly considered as several muscles, under the name of transversi and obliqui. 
A few of the oblique fibres are occasionally continued round the outer margin of 
the cartilage, and blend with the Thyro-arytenoid or the Arytaeno-epiglottideus 
muscle. 
The Thyro-arytcenoideus is a broad, flat muscle which lies parallel with the outer side 
of the true vocal chord. It arises in front from the lower half of the receding angle 
of the thyroid cartilage and from the crico-thyroid membrane. Its fibres pass hori- 
zontally backward and outward to be inserted into the base and .anterior surface of 
the arytenoid cartilage. This muscle consists of two fasciculi. The inferior or inner 
portion, the thicker, is inserted into the anterior angle of the base of the arytenoid 
cartilage and into the adjacent portion of its anterior surface; it lies parallel with 
the true vocal chord, to which it is adherent. The superior fasciculus, the thinner 
outer border of the posterior surface of the cricoid cartilage and the posterior margin of the. inferior 
cornu of the thyroid; this he calls the "musculus kerato-cricoideus." It is not found in every 
larynx, and when present exists usually only on one side, but is occasionally found on both sides. 
Mr. Turner (Edinburgh Medical Journal, Feb., 1860) states that it is found in about one case in five. 
Its action is to fix the lower horn of the thyroid cartilage backward and downward, opposing in 
some measure the part of the Crico-thyroid muscle, which is connected to the anterior margin of the 
horn. 926 
ORGANS OF VOICE AND RESPIRATION. 
and outer portion, is inserted into the anterior surface and outer border of the ary- 
tenoid cartilage above the preceding fibres; it lies on the outer side of the sacculus 
laryngis, immediately beneath its mucous lining. 
The muscles of the epiglottis are the 
Thyro-epiglottideus. 
Arytaeno-epiglottideus superior. 
Arytaeno-epiglottideus inferior. 
The Thyro-epiglottideus is a delicate fasciculus which arises from the inner sur- 
face of the thyroid cartilage, just external to the origin of the Thyro-arytenoid mus- 
cle, and spreads out upon the outer surface of the sacculus laryngis: some of its 
fibres are lost in the aryteno-epiglottidean fold, whilst others are continued forward 
to the margin of the epiglottis (Depressor epiglottidis). 
The Arytceno-epiglottideus superior consists of a few delicate muscular fasciculi 
which arise from the apex of the arytenoid cartilages, and become lost in the fold 
of mucous membrane extending between the arytenoid cartilage and side of the 
epiglottis (aryteno-epiglottidean folds}. 
The Arytceno-epiglottideus inferior (Compressor saceuli laryngis, Hilton) arises 
from the arytenoid cartilage, just above the attachment of the superior vocal chord; 
passing forward and upward, it spreads out upon the inner and upper part of the 
epiglottis. This muscle is separated from the preceding by an indistinct areolar 
interval.1 
Actions.-In considering the action of the muscles of the larynx, they may be 
conveniently divided into two groups-viz. : 1, those which open and close the 
glottis; 2, those which regulate the degree of tension of the vocal chords. 
1. The muscles which open the glottis are the Crico-arytaenoidei postici, and 
those which close it are the Arytaenoideus and the Crico-arytaenoidei laterales. 2. 
The muscles which regulate the tension of the vocal chords are the Crico-thyroidei, 
which make them tense and elongate them, and the Thyro-arytaenoidei, which relax 
and shorten them. The Thyro-epiglottideus is a depressor of the epiglottis, and the 
Arytaeno-epiglottidei constrict the superior aperture of the larynx, compress the 
sacculi laryngis, and empty them of their contents. 
The Crico-arytcenoidei postici separate the chordae vocales, and consequently open the glot- 
tis, by rotating the arytenoid cartilages outward around a vertical axis passing through the crico- 
arytenoid joints, so that their anterior angles and the ligaments attached to them become widely 
separated, the vocal chords at the same time being made tense. 
The Crico-arytcenoidei laterales close the glottis by rotating the arytenoid cartilages inward, 
so as to approximate their anterior angles. 
The Arytcenoideus muscles approximate the arytenoid cartilages, and thus close the opening 
of the glottis, especially at its back part. 
The Crico-thyroid muscles produce tension and elongation of the vocal chords. This was 
formerly supposed to be effected by drawing down the thyroid over the cricoid, but there seems 
to be good reason for believing that the thyroid cartilages are fixed by the Thyro-hyoid muscles, 
and that the Crico-thyroid muscles draw upward the front of the cricoid cartilage and so depress 
the posterior portion and with it the arytenoid cartilages, and thus elongate the vocal chords. 
The Thyro-arytcenoidei muscles, consisting of two parts having different attachments and dif- 
ferent directions, are rather complicated as regards their action. Their main use is to draw the 
arytenoid cartilages forward toward the thyroid, and thus shorten and relax the vocal chords. 
But owing to the connection of the inner portion with the vocal chord, this part, if acting sepa- 
rately, is supposed to modify its elasticity and tension, and the outer portion, being inserted into 
the outer part of the anterior surface of the arytenoid cartilage, may rotate it inward, and thus 
narrow the rima glottidis by bringing the two chords together. 
The Thyro-epiglottidei depress the epiglottis and assist in compressing the sacculi laryngis. 
The Arytaeno-epiglottideus superior constricts the superior aperture of the larynx when it is 
drawn upward during deglutition and the opening closed by the epiglottis. The Arytaeno-epi- 
glottideus inferior, together with some fibres of the Thyro-arytaenoidei, compress the sacculus 
laryngis. 
1 Musculus triticeo-glossus.-Bochdalek, jun. {Prager Vierteljahrsschrift, 2d Part, 1866), describes 
a muscle hitherto entirely overlooked, except a brief statement in Henle's Anatomy, which arises from 
the nodule of cartilage (corpus triticeum) in the posterior thyro-hyoid ligament, and passes forward 
and upward to enter the tongue along with the Kerato-glossus muscle. He met with this muscle 
eight times in twenty-two subjects. It occurred in both sexes, sometimes on both sides, at others on 
one only. THE TRACHEA. 
927 
The Mucous Membrane of the larynx is continuous above with that lining the 
mouth and pharynx, and is prolonged through the trachea and bronchi into the 
lungs. It lines the posterior and upper part of the anterior surface of the epiglot- 
tis, to which it is closely adherent, and forms the aryteno-epiglottidean folds which 
encircle the superior aperture of the larynx. It lines the whole of the cavity of 
the larynx, forms by its reduplication the chief part of the superior or false vocal 
chord, and from the ventricle is continued into the sacculus laryngis. It is then 
reflected over the true vocal chords, where it is thin and very intimately adherent, 
covers the inner surface of the crico-thyroid membrane and cricoid cartilage, and is 
ultimately continuous with the lining membrane of the trachea. It is covered with 
columnar ciliated epithelium below the superior vocal chord; but above this point 
the cilia are found only in front as high as the middle of the epiglottis. In the 
rest of its extent the epithelium is of the squamous variety. 
Glands.-The mucous membrane of the larynx is furnished with very many 
muciparous glands, the orifices of which are found in nearly every part; they are 
very numerous upon the epiglottis, being lodged in little pits in its substance; they 
are also found in large numbers along the posterior margin of the arytenoid-epiglot- 
tidean fold, in front of the arytenoid cartilages, where they are termed the arytenoid 
glands. They exist also in large numbers upon the inner surface of the sacculus 
larvngis. None are found on the vocal chords. 
Vessels and Nerves.-The arteries of the larynx are the laryngeal branches 
derived from the superior and inferior thyroid. The veins empty themselves into 
the superior, middle, and inferior thyroid veins. The lymphatics terminate in the 
deep cervical glands. The nerves are the superior laryngeal and the inferior or 
recurrent laryngeal branches of the pneumogastric nerves, joined by filaments from 
the sympathetic. The superior laryngeal nerves supply the mucous membrane of 
the larynx and the Crico-thyroid muscles. The inferior laryngeal nerves supply the 
remaining muscles. The Arytenoid muscle is supplied by both nerves. 
THE TRACHEA (Fig. 614). 
The Trachea, or Windpipe, is a cartilaginous and membranous cylindrical tube, 
flattened posteriorly, which extends from the lower part of the larynx, on a level 
with the sixth cervical vertebra, to opposite the fourth, or sometimes the fifth, dor- 
sal, where it divides into the two bronchi, one for each lung. The trachea measures 
about four inches and a half in length ; its diameter from side to side is from three- 
quarters of an inch to an inch, being always greater in the male than in the female. 
Relations.-The anterior surface of the trachea is convex, and covered in the 
neck, from above downward, by the isthmus of the thyroid gland, the inferior thy- 
roid veins, the arteria thyroidea ima (when that vessel exists), the Sterno-hyoid and 
Sterno-thyroid muscles, the cervical fascia (in the interval between those muscles), 
and, more superficially, by the anastomosing branches between the anterior jugular 
veins; in the thorax it is covered from before backward by the first piece of the 
sternum, the remains of the thymus gland, the left innominate vein, the arch of the 
aorta, the innominate and left carotid arteries, and the deep cardiac plexus. It lies 
upon the oesophagus, which is directed to the left near the arch of the aorta; later- 
ally, in the neck, it is in relation with the common carotid arteries, the lateral lobes 
of the thyroid gland, the inferior thyroid arteries, and recurrent laryngeal nerves; 
and in the thorax it lies in the interspace between the pleurae, having the pneumo- 
gastric nerve on each side of it. 
The Rig-ht Bronchus, wider, shorter, and more horizontal in direction than the 
left, is about an inch in length, and enters the right lung opposite the fifth dorsal 
vertebra. The vena azygos arches over it from behind, and the right pulmonary 
artery lies below, and then in front of it. 
The Left Bronchus is smaller, more oblique, and longer than the right, being 
nearly two inches in length. It enters the root of the left lung opposite the sixth ORGANS OF VOICE AND RESPIRATION. 
928 
Fig. 614. 
Superior* 
Cornu 
Inferior- 
Cornu 
Front View of Cartilages of Larynx: the Trachea and Bronchi. 
dorsal vertebra, about an inch lower than the right bronchus. It passes beneath 
the arch of the aorta, crosses, in front of the oesophagus, the thoracic duct and the 
descending aorta, and has the left pulmo- 
nary artery lying at first above, and then 
in front of it. If a transverse section is 
made across the trachea a short distance 
above its point of bifurcation, and a 
bird's-eye view taken of its interior 
(Fig. 615), the septum placed at the 
bottom of the trachea and separating 
the two bronchi will be seen to occupy 
the left of the median line, as was first 
shown by Mr. Goodall of Dublin, so that 
any solid body dropping into the trachea 
would naturally be directed toward the 
right bronchus; and this tendency is undoubtedly aided by the larger size of this 
Fig. 615. 
Transverse Section of the Trachea, just above its bi- 
furcation, with a bird's-eye view of the interior. THE TRACHEA. 
929 
tube as compared with its fellow. This fact serves to explain why a foreign sub- 
stance in the trachea generally falls into the right bronchus. 
Structure.-The trachea is composed of imperfect cartilaginous rings, fibrous 
membrane, muscular fibres, longitudinal yellow elastic fibres, mucous membrane, 
and glands. 
The Cartilages vary from sixteen to twenty in number: each forms an imper- 
fect ring, which surrounds about two-thirds of the cylinder of the trachea, being 
imperfect behind, where the tube is completed by fibrous membrane. The carti- 
lages are placed horizontally above each other, separated by narrow membranous 
intervals. They measure about two lines in depth and half a line in thickness. 
Their outer surfaces are flattened, but internally they are convex, from being thicker 
in the middle than at the margins. The cartilages are enclosed in an elastic fibrous 
membrane, which forms a double layer, one layer, the thicker of the two, passing 
over the outer surface of the ring, the other over the inner surface: at the upper 
and lower margins of the cartilages these two layers blend together to form a single 
membrane, which connects the rings one with another. They are thus, as it were, 
imbedded in the membrane. In the space behind, between the extremities of the 
rings, the membrane forms a single distinct layer. The peculiar cartilages are the 
first and the last. 
The first cartilage is broader than the rest, and sometimes divided at one end; 
it is connected by fibrous membrane with the lower border of the cricoid cartilage, 
with which or with the succeeding cartilage it is sometimes blended. 
The last cartilage is thick and broad in the middle, in consequence of its lower 
border being prolonged into a triangular hook-shaped process which curves down- 
ward and backward between the two bronchi. It terminates on each side in an 
imperfect ring, which encloses the commencement of the bronchi. The cartilage 
above the last is somewhat broader than the rest at its centre. Two or more of the 
cartilages often unite partially or completely, and are sometimes bifurcated at their 
extremities. They are highly elastic, and seldom ossify, even in advanced life. In 
the right bronchus the cartilages vary in number from six to eight; in the left, from 
nine to twelve. They are shorter and narrower than those of the trachea. 
The Muscular Fibres are disposed in two layers, longitudinal and transverse. 
The longitudinal fibres are the most external, and arise by minute tendons from 
the inner surfaces of the ends of the tracheal cartilages and from the fibrous mem- 
brane. 
The transverse fibres (Trachealis muscle, Todd and Bowman), the most internal, 
form a thin layer which extends transversely between the ends of the cartilages and 
the intervals between them at the posterior part of the trachea. The muscular 
fibres are of the unstriped variety. 
The Elastic Fibres form a complete lining to the entire cylinder of the trachea 
external to the mucous membrane: they are most abundant at the posterior part of 
the tube, between the extremities of the rings, where they are collected into distinct 
longitudinal bundles, and are especially numerous about the bifurcation of the 
trachea. They may be traced downward as a continuous membrane to the ultimate 
ramifications of the bronchial tubes. The fibres are contained in a loose submucous 
tissue together with numerous mucous glands. 
The Mucous Membrane contains a large amount of lymphoid tissue. It pre- 
sents a well-marked basement membrane, supporting a layer of columnar ciliated 
epithelium, between the deeper ends of which are smaller round or elongated 
cells. It is continuous above with that of the larynx, and below with that of the 
lungs. 
The Tracheal Glands are found in great abundance at the posterior part of the 
trachea. They are small flattened, ovoid bodies, placed upon the outer surface of 
the fibrous layer, each furnished with an excretory duct, which pierces the fibrous 
and muscular layers and opens on the surface of the mucous membrane. Some 
glands of smaller size are also found at the sides of the trachea, between the layers 
of fibrous tissue connecting the rings, and others immediately beneath the mucous 930 
ORGANS OF VOICE AND RESPIRATION. 
coat. The secretion from these glands serves to lubricate the inner surface of the 
trachea. 
Vessels and Nerves.-The trachea is supplied with blood by the inferior thy- 
roid arteries. The veins terminate in the thyroid venous plexus. The nerves are 
derived from the pneumogastric and its recurrent branches and from the sym- 
pathetic. 
Surgical Anatomy.-The air-passages may be opened in two different situations: through 
the crico-thyroid membrane {laryngotomy}, or in some part of the trachea {tracheotomy) ; and to 
these some surgeons have added a third method, by opening the crico-thyroid membrane and 
Fig. 616. 
Thyroid Cartilage' 
Crio o-thy to id Membrane - 
J S£ Artery 
Cree old Ca/rtilage - 
/Sfuyoeriar Thyroid win- 
Infer. Thyroid 
iiinominata 
Thyroid Zody 
(JstZmus > 
Surgical Anatomy of Laryngo-Tracheal Region, in the infant. 
dividing the cricoid cartilage with the upper ring of the trachea {laryngo-tracheotomy). The 
student should carefully consider the relative anatomy of the air-tube in each of these situations 
(Fig. 616). 
Laryngotomy is anatomically the most simple operation; it can most readily be performed, 
and should always be preferred when particular circumstances do not render the operation of 
tracheotomy absolutely necessary [or when instant operation is needful]. 
The crico-thyroid membrane is very superficial, being covered only in the middle line by the 
skin, superficial fascia, and the deep fascia. On each side of the middle line it is also covered 
by the Sterno-hyoid and Sterno-thyroid muscles, which diverge slightly from each other at their 
upper parts, leaving a slight interval between them. On these muscles rests the anterior jugular 
vein. The only vessel of any importance in connection with this operation is the crico-thyroid 
artery, which crosses the crico-thyroid membrane and which may be wounded, but rarely gives 
rise to any trouble. The operation is performed thus: The head being thrown back and steadied 
by an assistant, the finger is passed over the front of the neck and the crico-thyroid depression 
felt for. A vertical incision is then made through the skin in the middle line over this spot, and 
carried down through the fascia until the crico-thyroid membrane is exposed. A cross-cut is 
then made through the membrane close to the upper border of the cricoid cartilage, so as to 
avoid, if possible, the crico-thyroid artery, and a tracheotomy-tube introduced. It has been 
recommended, as a more rapid way of performing the operation, to make a transverse instead 
of a longitudinal cut through the superficial structures, and to cut at once into the air-passages 
It will seen, however, that in operating in this way the anterior jugular veins would be in danger 
of being wounded. 
Tracheotomy may be performed either above or below the isthmus of the thyroid body, or this 
structure may be divided and the trachea opened beneath it. 
The isthmus of the thyroid gland usually crosses the second and third rings of the trachea; 
along its upper border is frequently to be found a large transverse communicating branch be- 
tween the superior thyroid veins, and the isthmus itself is covered by a venous plexus formed 
between the thyroid veins of opposite sides. Theoretically, therefore, it is advisable to avoid 
dividing this structure in opening the trachea. THE PL EUR AE. 
931 
Above the isthmus the trachea is comparatively superficial, being covered by the skin, super- 
ficial fascia, deep fascia, Sterno-hyoid and thyroid muscles, and a second layer of the deep fascia, 
which, attached above to the lower border of the hyoid bone, descends beneath the muscles to 
the thyroid body, where it divides into two layers and encloses the isthmus. 
Below the isthmus the trachea lies much more deeply, and is covered by the Sterno-hyoid 
and the Sterno-thyroid muscles and a quantity of loose areolar tissue, in which is a plexus of 
veins, some of them of large size, and which converge to two trunks, the inferior thyroid veins, 
which descend on either side of the median line on the front of the trachea to open into the 
innominate veins. In the infant the thymus gland ascends a variable distance along the front 
of the trachea, and opposite the episternal notch the windpipe is crossed by the left innominate 
vein. Occasionally also, in young subjects, the innominate artery crosses the tube obliquely 
above the level of the sternum. The arteria thyroidea ima, when that vessel exists, passes from 
below upward along the front of the trachea. 
From these observations it must be evident that the trachea can be more readily opened above 
than below the isthmus of the thyroid body. 
Tracheotomy above the isthmus is performed thus: The patient should, if possible, be laid on 
his back on a table in a good light. A pillow is to be placed under the shoulders and the head 
thrown back and steadied by an assistant. The surgeon, standing on the right side of his patient, 
makes an incision from an inch and a half to two inches in length in the median line of the neck 
from the top of the cricoid cartilage. The incision must be made exactly in the middle line, so 
as to avoid the anterior jugular veins, and after the superficial structures have been divided the 
interval between the Sterno-hyoid muscles must be found, the raphe divided, and the muscles 
drawn apart. The lower border of the cricoid cartilage must now be felt for, and the upper 
part of the trachea exposed from this point downward in the middle line. Bose has recom- 
mended that the layer of fascia in front of the trachea should be divided transversely at the 
level of the lower border of the cricoid cartilage, and, having been seized with a pair of forceps, 
pressed downward with the handle of the. scalpel. By this means the isthmus of the thyroid 
gland is depressed and is saved from all danger of being wounded, and the trachea clearly 
exposed. The trachea is now transfixed with a sharp hook and drawn forward in order to 
steady it, and is then opened by inserting the knife into it and dividing the two or three upper 
rings of the trachea from below upward. If the trachea is to be opened below the isthmus, the 
incision must be made from a little below the cricoid cartilage to the top of the sternum. 
In the child the trachea is smaller, more deeply placed, and more movable than in the adult. 
In fat or short-necked people, or in those in whom the muscles of the neck are prominently 
developed, the trachea is more deeply placed than in the opposite conditions. 
[For a careful study of the " Anatomy of the Anterior Median Region of the Neck," with 
especial reference to tracheotomy in children, see Pilcher, Brooklyn Annals of Anatomy and 
Surgery, 1881. 
Intubation of the Larynx.-Dr. O'Dwyer has recently reintroduced this operation as a substi- 
tute for tracheotomy, with great ingenuity and success. A tube, varying in size according to 
the size and age of the patient, with a flange to prevent its slipping into the trachea, is tempo- 
rarily attached to a handle and introduced through the glottis into the larynx, the flange at the 
upper end resting on the vocal chords. 'The handle being now detached, the tube is left zn situ. 
It is removed also by a temporary handle.] 
Each lung is invested upon its external surface by an exceedingly delicate serous 
membrane, the Pleura, which encloses the organ as far as its root, and is then reflected 
upon the inner surface of the thorax. The portion of the serous membrane investing 
the surface of the lung is called the pleura pulmonalis (visceral layer of pleura), while 
that which lines the inner surface of the chest is called the pleura costalis (parietal 
layer of the pleura). The interspace or cavity between these two layers is called the 
cavity of the pleura. Each pleura is therefore a shut sac, one occupying the right, 
the other the left half of the thorax, and they are perfectly separate, not communi- 
cating with each other. The two pleurae do not meet in the middle line of the chest, 
excepting opposite the upper part of the second piece of the sternum ; an interspace 
is thus left between them which contains all the viscera of the thorax excepting the 
lungs : this is the mediastinum. 
Reflections of the Pleura (Fig. 617).-Commencing at the sternum, the pleura 
passes outward, covers the costal cartilages, the inner surface of the ribs and Inter- 
costal muscles, and at the back part of the thorax passes over the thoracic ganglia, 
and their branches, and is reflected upon the sides of the bodies of the vertebrae, 
where it is separated by a narrow interspace from the opposite pleura, the posterior 
mediastinum. From the vertebral column the pleura passes to the side of the peri. 
THE PLEURAE. 932 
ORGANS OF VOICE AND RESPIRATION. 
cardium, which it covers to a slight extent: it then covers the back part of the root 
of the lung, from the lower border of which a triangular fold descends vertically by 
the side of the posterior mediastinum to the Diaphragm. This fold is the broad liga- 
ment of the lung, the ligamentuni latum pulmonis, and serves to retain the lower part 
of that organ in position. From the root the pleura may be traced over the convex 
TRIANGULARIS STERNt 
Internal Mammary Vessels. x 
Fig. 617. 
Pleura Pulmonalis 
LeftPhrenic Nerve 
z Pleura Costalis 
■Mediastinum, 
Sympathetic Nerve ! 
Tiaraoio Duct 
Vena Azygos Major ) 
Pneumogastric Nerves I 
Posterior 
A Iransverse Section of the Thorax, showing the relative position of the viscera and. the reflections of the 
pleurae. 
surface of the lung, the summit, and base, and also over the sides of the fissures 
between the lobes. It covers its anterior surface and the front part of its root, and 
is reflected upon the side of the pericardium to the inner surface of the sternum. 
Below, it covers the upper surface of the Diaphragm; above, its apex projects, in 
the form of a cul-de-sac, through the superior opening of the thorax into the. neck, 
extending from one to two inches above the margin of the first rib, and receives the 
summit of the. corresponding lung ; this sac is strengthened, according to Dr. Sibson, 
by a dome-like expansion of fascia derived from that covering the lower part of the 
Scaleni muscles. 
A little above the middle of the sternum the contiguous surfaces of the two pleurae 
are sometimes in contact for a slight extent; but above and below this point the inter- 
val left between them forms the anterior mediastinum. 
The inner surface of the pleura is smooth, polished, and moistened by a serous 
fluid; its outer surface is intimately adherent to the surface of the lung and to the 
pulmonary vessels as they emerge from the pericardium; it is also adherent to the 
upper surface of the Diaphragm : throughout the rest of its extent it is somewhat 
thicker, and may be separated from the adjacent parts with extreme facility. 
The right pleural sac is shorter, wider, and reaches higher in the neck than the 
left. ° 
A essels AND Nerves.-The arteries of the pleura are derived from the inter- 
costal, the internal the musculo-phrenic, thymic, pericardiac, and bron- 
chial. The veins correspond to the arteries. The lymphatics are very numerous. 
The nerves are derived from the phrenic and sympathetic (Luschka). Kblliker MEDIASTINUM. 
933 
states that nerves accompany the ramification of the bronchial arteries in the pleura 
pulmonalis. 
MEDIASTINUM. 
The mediastinum is the space left in the median line of the chest by the non- 
approximation of the two pleurae. It extends from the sternum in front to the 
Fig. 618. 
The Posterior Mediastinum. 
spine behind, and contains all the viscera in the thorax excepting the lungs. The 
mediastinum may be divided for purposes of description into two parts: an upper 
portion, above the upper level of the pericardium, which is named the superior 934 
ORGANS OF VOICE AND RESPIRATION. 
mediastinum (Struthers), and a lower portion, below the upper level of the pericar- 
dium. This lower portion is again subdivided into three: that part which is con- 
tained and filled by the pericardium and its contents, the middle mediastinum; 
that part which is in front of the pericardium, the anterior mediastinum ; and that 
part which is behind the pericardium, the posterior mediastinum. 
The superior mediastinum is that portion of the interpleural space which lies 
above the upper level of the pericardium between the manubrium sterni in front 
and the upper dorsal vertebrae behind. It is bounded below by a plane passing 
backward from the junction of the manubrium and gladiolus sterni to the lower 
part of the body of the fourth dorsal vertebra (Thane) or third dorsal vertebra 
(Struthers). It contains the origins of the Sterno-hyoid and Sterno-thyroid mus- 
cles and the lower ends of the Longus colli muscles; the transverse portion of the 
arch of the aorta; the innominate, the left carotid, and subclavian arteries; the 
superior vena cava and the innominate veins and the left superior intercostal vein; 
the pneumogastric, cardiac, phrenic, and left recurrent laryngeal nerves; the trachea, 
oesophagus, and thoracic duct; the remains of the thymus gland and lymphatics. 
The anterior mediastinum is bounded in front by the sternum, on each side by 
the pleura, and behind by the pericardium. Owing to the oblique position of the 
heart toward the left side, this space is not parallel with the sternum, but directed 
obliquely from above downward and to the left of the median line; it is broad 
below, narrow above, very narrow opposite the second piece of the sternum, the 
contiguous surfaces of the two pleurae being occasionally united over a small space. 
The anterior mediastinum contains the origins of the Triangularis sterni muscles, 
the internal mammary vessels of the left side, and a quantity of loose areolar tissue 
in which some lymphatic vessels are found ascending from the convex surface of the 
liver, and two or three lymphatic glands (anterior mediastinal glands). 
The middle mediastinum is the broadest part of the interpleural space. It 
contains the heart enclosed in the pericardium, the ascending aorta, the superior 
vena cava, the bifurcation of the trachea, the pulmonary arteries and veins, and the 
phrenic nerves. 
The posterior mediastinum is an irregular triangular space running parallel 
with the vertebral column; it is bounded in front by the pericardium and roots of 
the lungs, behind by the vertebral column from the lower border of the fourth 
dorsal vertebra downward, and on either side by the pleura. It contains the 
descending portion of the arch and descending thoracic aorta, the greater and 
lesser azygos veins, the pneumogastric and splanchnic nerves, the oesophagus, tho- 
racic duct, and some lymphatic glands. 
THE LUNGS. 
The Lungs are the essential organs of respiration ; they are two in number, 
placed one in each of the lateral cavities of the chest, separated from each other by 
the heart and other contents of the mediastinum. Each lung is conical in shape, 
and presents for examination an apex, a base, two borders, and two surfaces. (See 
Fig. 619.) 
The apex forms a tapering cone which extends into the root of the neck about 
an inch to an inch and a half above the level of the first rib. [This cervical pro- 
longation of the lung above the clavicle is often forgotten in auscultation and per- 
cussion.] 
The base is broad, concave, and rests upon the convex surface of the Diaphragm; 
its circumference is thin, and fits into the space between the lower ribs and the 
costal attachment of the Diaphragm, extending lower down externally and behind 
than in front. 
The external or thoracic surface is smooth, convex, of considerable extent, and 
corresponds to the form of the cavity of the chest, being deeper behind than in front. 
The inner surface is concave. It presents in front a depression corresponding to THE LUNGS. 
935 
the convex surface of the pericardium, and behind a deep fissure (the hilum pulmo- 
nis) which gives attachment to the root of the lung. 
The posterior border is rounded and broad, and is received in the deep concavity 
on either side of the spinal column. It is much longer than the anterior border, and 
projects below between the ribs and the Diaphragm. 
The anterior border is thin and sharp, and overlaps the front of the pericardium. 
The anterior border of the right lung corresponds to the median line of the chest 
from the junction of the first and second pieces of the sternum as low as the sixth 
costal cartilage. The anterior border of the left lung lies in the mid-line only as 
low as the fourth costal cartilage; below this it presents a V-shaped notch, in which 
the pericardium is exposed. The two lungs are therefore in contact in the middle 
Fig. 619. 
Ductus Arteriosus 
JFront View of the Heart and Lungs. 
line, the pleura only being interposed between the levels of the second and fourth 
costal cartilages. 
Each lung is divided into two lobes, an upper and lower, by a long and deep 
fissure which extends from the upper part of the posterior border of the organ, 
about three inches from its apex, downward and forward to the lower part of its 
anterior border. This fissure penetrates nearly to the root. In the right lung the 
upper lobe is partially divided by a second and shorter fissure, which extends from 
the middle of the preceding, forward and upward, to the anterior margin of the 
organ, marking off a small triangular portion, the middle lobe. 
The right lung is the larger and heavier; it is broader than the left, owing to 
the inclination of the heart to the left side; it is also shorter by an inch, in con- 
sequence of the Diaphragm rising higher on the right side to accommodate the 
liver. 
A little above the middle of the inner surface of each lung, and nearer its pos- 936 
ORGANS OF VOICE AND RESPIRATION. 
terior than its anterior border, is its root, by which the lung is connected to the 
heart and the trachea. The root is formed by the bronchial tube, the pulmonary 
artery, the pulmonary veins, the bronchial arteries and veins, the pulmonary plexus 
of nerves, lymphatics, bronchial glands, and areolar tissue.-all of which are 
enclosed by a reflection of the pleura. The root of the right lung lies behind the 
superior vena cava and ascending portion of the arch of the aorta, and below the 
vena azygos. That of the left lung passes beneath the arch of the aorta and in 
front of the descending aorta; the phrenic nerve and the anterior pulmonary 
plexus lie in front of each, and the pneumogastric and posterior pulmonary plexus 
behind each. 
The chief structures composing the root of each lung are arranged in a similar 
manner from before backward on both sides-viz. the pulmonary veins most ante- 
rior, the pulmonary artery in the middle, and the bronchus, together with the bron- 
chial vessels, behind. 
From above downward, on the two sides, their arrangement differs, thus: on the 
right side their position is-bronchus, pulmonary artery, pulmonary veins; but 
on the left side their position is-pulmonary artery, bronchus, pulmonary veins; 
which is accounted for by the bronchus being placed on a lower level on the 
left than on the right side, in order that it may pass under the arch of the 
aorta. 
The weight of both lungs together is about forty-two ounces, the right lung 
being two ounces heavier than the left; but much variation is met with, according 
to the amount of blood or serous fluid they may contain. The lungs are heavier 
in the male than in the female, their proportion to the body being in the former as 
1 to 37; in the latter, as 1 to 43. The specific gravity of the lung-tissue varies 
from 0.345 to 0.746, water being 1000. 
The color of the lungs at birth is a pinkish white; in adult life, a dark slate- 
color, mottled in patches; and as age advances this mottling assumes a black color. 
The coloring matter consists of granules of a carbonaceous substance deposited 
in the areolar tissue near the surface of the organ. It increases in quantity as 
age advances, and is more abundant in males than in females. The posterior 
border of the lung is usually darker than the anterior. The surface of the lung 
is smooth, shining, and marked out into numerous polyhedral spaces, indicating 
the lobules of the organ : the area of each of these spaces is crossed by numerous 
lighter lines. 
The substance of the lung is of a light, porous, spongy texture; it floats in 
water, and crepitates when handled, owing to the presence of air in the tissue. It 
is also highly elastic; hence the collapsed state of these organs when they are 
removed from the closed cavity of the thorax. 
Structure.-The lungs are composed of an external serous coat, a subserous 
areolar tissue, and the pulmonary substance or parenchyma. 
The serous coat is derived from the pleura; it is thin, transparent, and invests 
the entire organ as far as the root. 
The subserous areolar tissue contains a large proportion of elastic fibres; it 
invests the entire surface of the lung and extends inward between the lobules. 
The parenchyma is composed of lobules, which, although closely connected 
together by an interlobular areolar tissue, are quite distinct from one another, 
and may be teased asunder without much difficulty in the foetus. The lobules vary 
in size: those on the surface are large, of pyramidal form, the base turned toward 
the surface; those in the interior smaller and of various forms. Each lobule 
is composed of one of the ramifications of the bronchial tube and its terminal air- 
cells, and of the ramifications of the pulmonary and bronchial vessels, lymphat- 
ics, and nerves, all of these structures being connected together by areolar fibrous 
tissue. 
The bronchus upon entering the substance of the lung divides and subdivides 
dichotomously throughout the entire organ. Sometimes three branches arise 
together, and occasionally small lateral branches are given off' from the sides of THE LUNGS. 
937 
a main trunk. Each of the smaller subdivisions of the bronchi enters a pul- 
monary lobule (lobular bronchial tube), and, again subdividing, ultimately ter- 
minates in the intercellular passages and air-cells of which the lobule is composed. 
Within the lungs the bronchial tubes are circular, not flattened, and their constit- 
uent elements present the following peculiarities of structure: 
The cartilages are not imperfect rings, but consist of thin laminae, of varied 
form and size, scattered irregularly along the sides of the tube, being most distinct 
at the points of division of the bronchi. They may be traced into tubes the diam- 
eter of which is only one-fourth of a line. Beyond this point the tubes are wholly 
membranous. The fibrous coat and the longitudinal elastic fibres are continued into 
the smallest ramifications of the bronchi. The muscular coat is disposed in the form 
of a continuous layer of annular fibres, which may be traced upon the smallest bron- 
chial tubes; they consist of the unstriped variety of muscular fibre. The mucous 
membrane lines the bronchi and its ramifications throughout, and is covered with 
columnar ciliated epithelium. 
According to the observations of Mr. Rainey,1 the lobular bronchial tubes, on 
entering the substance of the lobules, divide and subdivide from four to nine times, 
according to the size of the lobule, continuing to diminish in size until they attain 
a diameter of to -g1 of an inch. They then become changed in structure, losing 
their cylindrical form, and are continued onward as irregular passages (infundibula, 
-intercellular passages, Rainey-air-sacs, Waters) through the substance of the 
lobule, their sides and extremities being closely covered by numerous saccular 
dilatations, the air-cells. This arrangement resembles most closely the naked-eye 
appearances observed in the reticulated structure of the lung of the tortoise and 
other Reptilia. Opinions have differed as to the existence of communications or 
anastomoses between the intercellular passages, or air-sacs. According to Dr. 
Waters,2 these air-sacs, as he terms them, are arranged in groups or "lobulettes" 
of five or six, which spring from the terminal dilatation of a single bronchial tube, 
but have no other communication with each other or with neighboring lobulettes 
than that which is afforded by their common connection with the bronchial tubes. 
The air-cells, alveoli (Waters), are small, polyhedral, alveolar recesses separated 
from each other by thin septa and communicating freely with the intercellular pas- 
sages or air-sacs. They are well seen on the surface of the lung, and vary from 
tV an inch ln diameter, being largest on the surface at the thin borders 
and at the apex, and smallest in the interior. 
The constituent elements of the bronchial tubes at their termination in the inter- 
cellular passages become changed: their w'alls are now formed by an interlacing of 
the longitudinal elastic bundles with fibrous tissue; the muscular fibres disappear, 
and the mucous membrane becomes thin and delicate and lined with a layer of tes- 
sellated epithelium. The latter membrane lines the air-cells, and forms by its redu- 
plications the septa intervening between them. 
The Pulmonary Artery conveys the venous blood to the lungs: it divides into 
branches which accompany the bronchial tubes, and terminates in a dense capillary 
network upon the walls of the intercellular passages and air-cells. From this net- 
work the radicles of the pulmonary veins arise; coalescing into large branches, they 
accompany the arteries, and return the blood, purified by its passage through the 
capillaries, to the left auricle of the heart. In the lung the branches of the pulmo- 
nary artery are usually above and in front of a bronchial tube, the vein below. 
The Pulmonary Capillaries form plexuses which lie immediately beneath the mu- 
cous membrane, in the walls and septa of the air-cells, and of the intercellular passages. 
In the septa between the air-cells the capillary network forms a single layer. The cap- 
illaries form a very minute network [Fig. 60, p. 81], the meshes of which are smaller 
than the vessels themselves;3 their walls are also exceedingly thin. The vessels of 
1 Medico-Chirurgical Transactions, vol. xxviii., 1845. 
2 The Anatomy of the Tinman Lung, 1860, pp. 136-150. 
3 The meshes are only 0.002zzz to 0.008zzz in width, while the vessels are 0.003zzz to 0.005zzz (Kol- 
liker, Human Microscopic Anatomy). 938 
ORGANS OF VOICE AND RESPIRATION. 
RECURRENT LARYNGEAL NERVE: 
FIRST DORSAL VERTEBRA 
THORacig 
DUCT 
THORACIC DUCT 
(ESOPHAGUS 
Fig. 620.-The Roots of the Lungs and Posterior Pulmonary Plexus, seen from behind. THYROID GLAND. 
939 
neighboring lobules are distinct from each other, and do not anastomose; and, accord- 
ing to Dr. Waters, those of the separate groups of intercellular passages, or air-sacs 
(which groups he denominates lobulettes), are also independent; so that in the septa 
between two adjoining lobulettes there would be a double layer of capillaries, one 
layer belonging to each of the adjacent air-sacs or intercellular passages. If this 
is really the arrangement of the vessels, it would follow that in the septa between 
the air-cells (or alveoli) the blood in the capillaries would be exposed on all sides to 
the action of the air, since it is circulating in a single layer of vessels, which is in 
contact with the membrane of the air-passages on both sides, but that in the septa 
between the intercellular passages (or air-sacs) the blood in the double layer of cap- 
illaries will be in contact with the air on one side only. 
The Bronchial Arteries supply blood for the nutrition of the lung: they are 
derived from the thoracic aorta, and, accompanying the bronchial tubes, are dis- 
tributed to the bronchial glands and upon the walls of the larger bronchial tubes 
and pulmonary vessels, and terminate in the deep bronchial veins. Others are dis- 
tributed in the interlobular areolar tissue, and terminate partly in the deep, partly 
in the superficial, bronchial veins. Lastly, some ramify upon the walls of the 
smallest bronchial tubes, communicate with the pulmonary capillary plexus, and 
terminate in the pulmonary veins. 
The Bronchial Vein is formed at the root of the lung, receiving superficial and 
deep veins corresponding to branches of the bronchial artery. It does not, how- 
ever, receive all the blood supplied by the artery, some of it passing into the pul- 
monary vein. It terminates on the right side in tbe vena azygos major, and on 
the left side in the superior intercostal vein. 
The Lymphatics consist of a superficial and deep set: they terminate at the root 
of the lung in the bronchial glands. 
Nerves.-The lungs are supplied from the anterior and posterior pulmonary 
plexuses, formed chiefly by branches from the sympathetic and pneumogastric. 
The filaments from these plexuses accompany the bronchial tubes, upon which they 
are lost. Small ganglia are found upon these nerves. 
THYROID GLAND. 
The Thyroid G-land bears much resemblance in structure to other glandular 
organs, and was formerly classified, together with the thymus, suprarenal capsules, 
and spleen, under the head of ductless glands, 
since it has no excretory duct. Its function 
is unknown, but from its situation in connec- 
tion with the trachea and larynx the thyroid 
body is usually described with those organs, 
although it takes no part in the function of 
respiration. It is situated at the upper part 
of the trachea, and consists of two lateral 
lobes placed one on each side of that tube 
and connected together by a narrow trans- 
verse portion, the zstA/nus. 
Its anterior surface is convex, and cov- 
ered by the Sterno-hyoid, Sterno-thyroid, 
and Omo-hyoid muscles. 
Its lateral surfaces, also convex, lie in 
contact with the sheath of the common 
carotid artery. 
Its posterior surface is concave, and em- 
braces the trachea and larynx. The poste- 
rior borders of the gland extend as far back 
as the lower part of the pharynx. 
Fig. 621. 
Two Lobules from the Thyroid of an Infant: a, 
small glandular vesicles with their cells; &, the 
same with incipient colloid metamorphosis, more 
strongly marked at c; d, coarse lymph-canals; 
e, fine radicles of the same ; f, an efferent vessel 
of considerable size. 940 
ORGANS OF VOICE AND RESPIRATION. 
The thyroid is of a brownish-red color. Its weight varies from one to two ounces. 
It is larger in females than in males, and becomes slightly increased in size during 
menstruation [and after maternity]. It occasionally becomes enormously hypertro- 
phied, constituting the disease called bronchocele or goitre. Each lobe is somewhat 
conical in shape, about two inches in length and three-quarters of an inch to an inch 
and a quarter in breadth, the right lobe being the larger of the two. 
The isthmus connects the lower third of the two lateral lobes; it measures about 
half an inch in breadth and the same in depth, and usually covers the second and 
third rings of the trachea. Its situation presents, however, many variations, a 
point of importance in the operation of tracheotomy. Sometimes the isthmus is 
altogether wanting. 
A third lobe, of conical shape, called the pyramid, occasionally arises from the 
upper part of the isthmus or from the adjacent portion of either lobe, but most 
commonly the left, and ascends as high as the hyoid bone. It is occasionally quite 
detached or divided into two parts, or altogether wanting. 
A few muscular bands are occasionally found attached above to the body of the 
hyoid bone, and below to the isthmus of the gland or its pyramidal process. These 
form a muscle which was named by Sbemmerring the Levator glandulce thyroideoe. 
Structure.-The thyroid body is invested by a thin capsule of connective tissue, 
which projects into its substance and imperfectly divides it into masses of irregular 
Fig. 622. 
Minute Structure of Thyroid, from a transverse section of the thyroid of a dog, semi-diagrammatic (from Dr. 
Baber's paper, Philosophical Transactions of the Royal Society, vol. clxvi. pt. ii. p. 557): a, lumen of an artery, 
seen in transverse section; b, cross-section of a large lymphatic vessel that surrounds it, filled with a gran- 
ular material; c, contents of the vesicles, which present a similar appearance to b ; d, walls of gland-vesi- 
cles, the epithelial cells of which are flattened by the action of reagents. 
form and size. When the organ is cut into it is seen to be made up of a number 
of closed vesicles containing a yellow glairy fluid and separated from each other by 
intermediate connective tissue. 
According to Dr. Baber, who has recently published some important observations 
on the minute structure of the thyroid,1 the vesicles of the thyroid of the adult ani- 
mal are generally closed cavities; but in some young animals (e. g. young dogs) the 
vesicles are more or less tubular and branched. This appearance he supposes to be 
due to the mode of growth of the gland, and merely indicating that an increase in 
the number of vesicles is taking place. Each vesicle is lined by a single layer of 
epithelium, the cells of which, though differing somewhat in shape in different ani* 
1 "Researches on the Minute Structure of the Thyroid Gland," Phil. Trans., Part iii., 1881. THYMUS GLAND. 
941 
mals, have always a tendency to assume a columnar form. Between the epithelial 
cells exists a delicate reticulum. The vesicles are of various sizes and shapes, and 
contain as a normal product a viscid, homogeneous, semifluid, slightly yellowish 
material, which frequently contains blood, the red corpuscles of which are found 
in it in various stages of disintegration and decolorization, the yellow tinge being 
probably due to the haemoglobin, which is thus set free from the colored corpuscles. 
Baber has also described in the thyroid gland of the dog large round cells (" paren- 
chymatous cells "), each provided with a single oval-shaped nucleus, which migrate 
into the interior of the gland-vesicles. 
The capillary blood-vessels form a dense plexus in the connective tissue around 
the vesicles, between the epithelium of the vesicles and the endothelium of the 
lymph-spaces, which latter surround a greater or smaller part of the circumference 
of the vesicle. These lymph-spaces empty themselves into lymphatic vessels 
which run in the interlobular connective tissue, not uncommonly surrounding the 
arteries which they accompany, and communicate with a network in the cap- 
sule of the gland. Baber has found in the lymphatics of the thyroid a viscid 
material which is morphologically identical with the normal constituent of the 
vesicle. 
From this it follows that one of the functions of the thyroid is the destruction 
of the colored corpuscles in the vesicles, and their removal and final discharge into 
the general circulation by the lymphatics. 
Vessels and Nerves.-The arteries supplying the thyroid are the superior 
and inferior thyroid, and sometimes an additional branch (thyroidea media or ima) 
from the arteria innominata or the arch of the aorta, which ascends upon the front 
of the trachea. The arteries are remarkable for their large size and frequent anas- 
tomoses. The veins form a plexus on the surface of the gland and on the front of 
the trachea, from which arise the superior, middle, and inferior thyroid veins, the 
two former terminating in the internal jugular, the lattei' in the vena innominata. 
The lymphatics are numerous, of large size, and terminate in the thoracic and right 
lymphatic ducts. They are thus described by Frey: " The whole envelope of the 
organ is covered by knotted trunks, which take their origin from a network of very 
complicated canals situated in a deeper layer of the former. This latter network is 
formed around the secondary lobules of the gland by the reticular intercommunica- 
tions of these canals (Fig. 621,/). From the peripheral network formed of canals 
burrowing through the connective tissue of the capsule lateral ramifications are given 
off which penetrate into the interior, and gradually enclose the primary lobes in com- 
plete rings or more or less perfect arches (cZ, d). From these a few fine terminal pas- 
sages with blind ends (e) are seen sinking in between the different vesicles." The 
nerves are derived from the pneumogastric1 and from the middle and inferior cer- 
vical ganglia of the sympathetic. 
The thymus gland presents much resemblance in structure to other glandular 
organs, and is another of the organs which used formerly to be denominated duct- 
less glands. 
The thymus gland is a temporary organ, attaining its full size at the end of the 
second year, when it ceases to grow, and gradually dwindles until at puberty it has 
almost disappeared. If examined when its growth is most active it will be found to 
consist of two lateral lobes placed in close contact along the middle line, situated 
partly in the superior mediastinum, partly in the neck, and extending from the 
fourth costal cartilage upward as high as the lower border of the thyroid gland. It 
is covered by the sternum and by the origins of the Sterno-hyoid and Sterno-thyroid 
muscles. Below it rests upon the pericardium, being separated from the arch of the 
THYMUS GLAND. 
1 Frey denies that the vagus supplies any of these nerves, deriving them entirely from the 
sympathetic. 942 
ORGANS OF VOICE AND RESPIRATION. 
aorta and great vessels by the thoracic fascia. In the neck it lies on the front and 
sides of the trachea, behind the Sterno-hyoid and Sterno-thyroid muscles. The two 
lobes generally differ in size; they are occasionally united so as to form a single 
mass, and sometimes separated by an intermediate lobe. The thymus is of a pink- 
ish-gray color, soft, and tabulated on its surfaces. It is about two inches in length, 
one and a half in breadth below, and about three or four lines in thickness. At 
birth it weighs about half an ounce. 
Structure.-Each lateral lobe is composed of numerous lobules held together by 
delicate areolar tissue, the entire gland being enclosed in an investing capsule of a 
similar but denser structure. The primary lobules vary in size from a pin's head to 
a small pea, and are made up of a number of small 
nodules or follicles which are irregular in shape and 
are more or less fused together, especially toward the 
interior of the gland. According to Watney, each 
follicle consists of a medullary and a cortical portion, 
which differ in many essential particulars from each 
other. The cortical portion is mainly composed of 
lymphoid cells supported by a delicate reticulum. In 
addition to this reticulum, of which traces only are 
found in the medullary portion, there is also a network 
of finely branched cells which is continuous with a 
similar network in the medullary portion. This net- 
work forms an adventitia to the blood-vessels. In the 
medullary portion there are but few lymphoid cells, 
but there are, especially toward the centre, granular 
cells and concentric corpuscles. The granular cells 
are rounded or flask-shaped masses attached (often by 
fibrillated extremities) to blood-vessels and to newly- 
formed connective tissue. The concentric corpuscles 
are composed of a central mass consisting of one or 
more granular cells, and of a capsule which is formed 
of epithelioid cells which are continuous with the 
branched cells forming the network mentioned above. 
Each follicle is surrounded by a capillary plexus, 
from which vessels pass into the interior, and radiate 
from the periphery toward the centre, and form a 
second zone just within the margin of the medullary 
portion. In the centre of the medulla there are very 
few vessels, and they are of minute size. 
Dr. Watney has recently made the important observation that haemoglobin is 
found in the thymus, either in cysts or in cells situated near to or forming part of 
the concentric corpuscles. This haemoglobin varies from granules to masses exactly 
resembling colored blood-corpuscles, oval in the bird, reptile, and fish; circular in 
all mammals except in the camel. Dr. Watney has also discovered, in the lymph 
issuing from the thymus, similar cells to those found in the gland, and, like them, 
containing haemoglobin, in the form of either granules or masses. From these facts 
he arrives at the physiological conclusion that the thymus is one source of the col- 
ored blood-corpuscles. 
These points are illustrated in the accompanying drawing by Dr. Watney (Fig. 
624), for which I have to express my thanks to him. 
Vessels and Nerves.-The arteries supplying the thymus are derived from 
the internal mammary and from the superior and inferior thyroid. The veins ter- 
minate in the left vena innominata and in the thyroid veins. The lymphatics are 
of large size, arise in the substance of the gland, and are said to terminate in the 
internal jugular vein. Sir A. Cooper believed that these vessels carried into the 
blood the secretion formed in the substance of the thymus. The nerves are exceed- 
ingly minute; they are derived from the pneumogastric and sympathetic. Branches 
Fig. 623. 
1. Upper portion of the thymus of a 
fcetal pig of 2'' in in length, show- 
ing the bud-like lobuli and gland- 
ular elements. 2. Cells of the thy- 
mus, mostly from a man: a, free 
nuclei; ft, small cells; c, larger; d, 
larger, with oil-globules, from the 
ox; e,f, cells completely filled with 
fat, at f, without a nucleus; g, h, 
concentric bodies; g, an encapsu- 
lated nucleated cell; h, a composite 
structure of a similar nature. THYMUS GLAND. 
943 
Fig. 624. 
X VEIN 
ARTERY 
CONCENTRIC 
CORPUSCLE 
ARTERY- 
VEIN 
ARTERY- 
GRANULAR CELLS 
-ARTERY 
-VEIN 
Minute Structure of Thymus Gland; follicle of injected thymus from calf four days old, slightly diagrammatic 
(magnified about 50* diameters). The large vessels are disposed in two rings, one of which surrounds the 
follicle, the other lies just within the margin of the medulla: a and b, from thymus of camel, examined 
without addition of any reagent (magnified about 400 diameters), a, large colorless cell containing small 
oval masses of haemoglobin: similar cells are found in the lymph-glands, spleen, and medulla of bone; 
b, colored blood-corpuscle. 
from the descendens noni and phrenic reach the investing capsule, but do not pen- 
etrate into the substance of the gland. The Urinary Organs. 
THE KIDNEYS. 
THE Kidneys, two in number, are situated in the back part of the abdomen, 
and are for the purpose of separating from the blood certain materials which, 
when dissolved in a quantity of water, also separated from the blood by the kidneys, 
constitute the urine. [Occasionally, there is but a single kidney.] 
They are placed in the loins, one on each side of the vertebral column, behind 
the peritoneum, and surrounded by a mass of fat and loose areolar tissue. [Some- 
times, instead of being fixed in place by this tissue, the kidney is loose, and only 
held by the ureter and the blood-vessels. It is then called a "floating" kidney.] 
Their upper extremity is on a level with the upper border of the twelfth dorsal 
vertebra, their lower extremity on a level with the third lumbar. The right kidney 
is usually on a slightly lower level than the left, probably on account of the vicinity 
of the liver. 
The kidneys rest on the lower part of the Diaphragm and the fascia covering 
the Quadratus lumborum and the Psoas magnus muscles. The right one is covered 
in front by the right lobe of the liver, the descending portion of the duodenum, and 
the ascending colon; the left one has in front the fundus of the stomach, the tail of 
the pancreas, and the descending colon. 
The kidney has a characteristic form. It is flattened on its sides, and presents 
at one part of its circumference a hollow. It is larger at its upper than its lower 
extremity. It presents for examination two surfaces, two borders, and an upper 
and lower extremity. Its anterior surface is convex, looks forward and outward, 
and is partially covered by peritoneum. The upper part of this surface on the 
right side is in contact with the under surface of the right lobe of the liver, on 
which it produces a slight concave impression, the impressio renalis (p. 892); 
below this the descending portion of the duodenum and the upper part of the 
ascending colon are connected to this surface by a quantity of loose areolar tissue. 
On the left side the upper part of the anterior surface of the kidney is in contact 
with the under surface of the stomach, and below this with the left extremity of 
the pancreas, whilst the lower part is connected to the descending colon by loose 
areolar tissue. 
The posterior szirface is flatter than the anterior, and is imbedded in areolar 
tissue, which separates the upper part from the Diaphragm covering the eleventh 
and twelfth ribs, and the lower part from the anterior lamellae of the lumbar fascia 
covering the Quadratus lumborum muscle, and internally from the fascia covering 
the Psoas magnus muscle. 
The external border is convex, and is directed outward and backward toward 
the postero-lateral wall of the abdomen. On the left side it is in contact at its 
upper part with the spleen. 
The internal border is concave, and is directed forward and a little downward. 
It presents a deep longitudinal fissure bounded by a prominent overhanging ante- 
rior and posterior lip. This fissure is named the hilum, and allows of the passage 
of the vessels, nerves, and ureter into and out of the kidney. 
The superior extremity, directed slightly inward as well as upward, is thick and 
rounded and is surmounted by the suprarenal capsule, which covers also a small 
portion of the anterior surface. 
The inferior extremity, directed a little outward as well as downward, is smaller 
944 THE KIDNEYS. 
945 
and thinner than the superior. It extends to within one or two inches of the crest 
of the ilium. 
At the hilum of the kidney the relative position of the main structures passing 
into and out of the kidney is as follows: The vein is in front, the artery in the 
middle, and the duct or ureter behind and toward the lower part. By a knowledge 
of these relations the student may distinguish between the right and the left kidney. 
The kidney is to be laid on the table before the student on its posterior surface, 
with its lower extremity toward the observer; that is to say, with the ureter behind 
and below the other vessels; the hilum will then be directed to the side to which 
the kidney belongs. 
Each kidney is about four inches in length, two to two and a half in breadth, 
and rather more than one inch in thickness. The left is somewhat longer, though 
narrower, than the right. The weight of the kidney in the adult male varies from 
4| oz. to 6 oz.; in the adult female, from 4 oz. to 5| oz. The combined weight of 
the two kidneys in proportion to the body is about 1 in 240. 
[The operations of nephrotomy (incision of the kidney) and nephrectomy 
(removal of the kidney) and nephro-lithotomy (removal of stone from the kidney) 
have recently obtained a well-recognized and very successful place in surgery. 
They may all be done by the lumbar incision, without involving the peritoneum, 
and the relation of the kidney should be observed with a view to these operations 
(Figs. 586 and 587, pp. 884, 885). Removal of the kidney is also done by abdom- 
inal section.] 
General Structure of the Kidney.-The kidney is surrounded by a distinct 
investment of fibrous tissue which forms a firm, smooth covering to the organ. It 
closely invests it, but can be easily stripped off; in doing which, however, numer- 
ous fine processes of connective tissue and small blood-vessels are torn through. 
Beneath this coat a thin, wide-meshed network 
of unstriped muscular fibre forms an incomplete 
covering to the organ. When the fibrous coat is 
stripped off, the surface of the kidney is found to 
be smooth and even and of a deep-red color. 
In infants fissures extending for some depth 
may be seen on the surface of the organ-a rem- 
nant of the lobular construction of the gland. The 
kidney is dense in texture, but is easily lacerable 
by mechanical force. In order to obtain a know- 
ledge of the structure of the gland a vertical sec- 
tion must be made from its convex to its concave 
border, and the loose tissue and fat removed from 
around the vessels and the excretory duct (Fig. 
625). It will be then seen that the kidney con- 
sists of a central cavity surrounded at all parts 
but one by the proper kidney-substance. This 
central cavity is called the sinus, and is lined by 
a prolongation of the fibrous coat of the kidney, 
which enters through a longitudinal fissure, the 
hilum (before mentioned), which is situated at 
that part of the cavity which is not surrounded 
bv kidney-structure. Through this fissure the 
blood-vessels of the kidney and its excretory duct 
pass, and therefore these structures upon entering 
the kidney are contained within the sinus. I he 
excretory duct or ureter after entering dilates into 
a wide, funnel-shaped sac named the pelvis. This 
divides into two or three tubular divisions, which again divide into several short, 
truncated branches named calices or infundibula, all of which are contained in the 
central cavity of the kidney. The blood-vessels of the kidney after passing through 
Fig. 625. 
Vertical Section of Kidney. 946 
THE URINARY ORGANS. 
the hilum are contained in the sinus or central cavity, lying between its lining mem- 
brane and the excretory apparatus, before entering the kidney-substance. 
This central cavity, as before mentioned, is surrounded on all sides, except at 
the hilum, by the substance of the kidney, which is at once seen to consist of two 
parts-viz. of an external, granular, investing part, which is called the cortical por- 
tion; and of an internal part, the medullary portion, made up of a number of dark- 
colored pyramidal masses, with their bases resting on the cortical part and their 
apices converging toward the centre, where they form prominent papillae which pro- 
ject into the interior of the calices. 
The cortical substance is of a bright reddish-brown color, soft, granular, and 
easily lacerable. It is found everywhere immediately beneath the capsule, and is 
seen to extend itself in an arched form over the base of each medullary pyramid. 
The part separating the sides of any two pyramids through which the arteries and 
nerves enter and the veins and lymphatics emerge from the kidney is called a cor- 
tical column or column of Bertini (a, a', Fig. 625), whilst that portion which stretches 
from one cortical column to the next, and intervenes between the base of the pyra- 
mid and the capsule (which is marked by the dotted line extending from A to Az in 
Fig. 625), is called a cortical arch, the depth of which varies from a third to half an 
inch. 
The medullary substance, as before said, is seen to consist of palish red-colored 
striated conical masses, the pyramids of Malpighi, the number of which, varying 
from eight to eighteen, correspond to the number of lobes of which the organ in 
the foetal state is composed. The base of each pyramid 
is surrounded by a cortical arch and directed toward the 
circumference of the kidney; the sides are contiguous 
with the cortical columns; whilst the apex, known as 
the papilla or mammilla of the kidney, projects into 
one of the calices of the ureter. 
These two parts, cortical and medullary, so dissimilar 
in appearance, are very similar in structure, being made 
up of urinary tubes and blood-vessels united and bound 
together by a connecting matrix or stroma. 
The tubuli uriniferi, of which the kidney is for the 
most part made up, commence in the cortical portion of 
the kidney by spherical closed sacs, called Malpighian 
capsules, and after pursuing a very circuitous course 
through the cortical and medullary parts of the kidney, 
finally terminate at the apices of the Malpighian pyra- 
mids by open mouths (Fig. 626), so that the fluid which 
they contain is emptied into the dilated extremity of the 
ureter contained in the sinus of the kidney. If the sur- 
face of one of the papillae be examined with a lens, it 
will be seen to be studded over with a number of small 
depressions, from sixteen to twenty in number, and in a 
fresh kidney, upon pressure being made, fluid will be 
seen to exude from these depressions. They are the ori- 
fices of the tubuli uriniferi, which terminate in this sit- 
uation. They commence in the cortical portion of the 
kidney as the Malpighian bodies, which are small 
rounded masses, varying in size, but of an average of 
about of an inch in diameter. They are of a deep- 
red color, and are found only in the cortical portion of 
the kidney. Each of these little bodies is composed of 
two parts-a central glomerulus of vessels called a Mal- 
pighian tuft, and a membranous envelope, the Malpighian capsule or capsule of 
Bowman, which latter is a small pouch-like commencement of a uriniferous tubule. 
The Malpighian tuft, or vascular glomerulus, is a network of convoluted capil- 
Fig. 626. 
A, a, Malpighian bodies; b, b, mar- 
gin of medullary structure; c, c, c, 
loops of Henle; d, d, d, straight 
tubes cut off; e, commencing 
straight tubes; f, termination of 
straight tube. THE KIDNEYS. 
947 
lary blood-vessels held together by scanty connective tissue and grouped into from 
two to five lobules. This capillary network is derived from a small arterial twig, the 
afferent vessel, which pierces the wall of the capsule, generally at a point opposite 
that at which it is connected with the tube; and the resulting vein, the efferent 
vessel, emerges from the capsule at the same point. The afferent vessel is usually 
the larger of the two (Fig. 627). The Malpighian or Bowman s capsule, which 
surrounds the glomerulus, is formed of a hyaline membrane, supported by a small 
amount of connective tissue, which is continuous with the connective tissue of the 
tube. It is lined on its inner surface by a layer of squamous epithelial cells, which 
are reflected from the lining membrane on to the glomerulus at the point of entrance 
or exit of the afferent and efferent vessels. The whole surface of the glomerulus is 
covered with a continuous layer of the same cells on a delicate supporting membrane, 
Fig. 627. 
Fig. 628. 
Minute Structure of Kidney. 
Malpighian Body. 
which with the cells dip in between the lobules of the glomerulus, closely surround- 
ing them (Fig. 628). Thus between the glomerulus and the capsule a space is left, 
forming a cavity lined by a continuous layer of cells which varies in size according 
to the state of secretion and the amount of fluid present in it. The cells, as above 
stated, are squamous in the adult, but in the foetus and young subject are polyhedral 
or even columnar. 
The tubuli uriniferi, commencing in the Malpighian bodies, in their course pre- 
sent many changes in shape and direction, and are contained partly in the medullary 
and partly in the cortical portions of the organ. At their junction with the Malpigh- 
ian capsule they present a somewhat constricted portion, which is termed the 
Beyond this the tube becomes convoluted, and pursues a considerable course in the 
cortical structure, constituting the proximal convoluted tube. After a time the con- 
volutions disappear, and the tube approaches the medullary portion of the kidney 
in a more or less spiral manner. This section of the tube has been called the spiral 
tubule of Schachowa. Throughout this portion of their course the tubuli uriniferi 
have been contained entirely in the cortical structure, and have presented a pretty 
uniform calibre. They now enter the medullary portion, suddenly become much 
smaller, quite straight in direction, and dip down for a variable depth into the pyra- 
mids, constituting the descending limb of Henle's loop. Bending on themselves, they 
form a kind of "loop, the loop of Henle, and, reascending, they become suddenly 
enlarged and again spiral in direction, forming the ascending limb of Henle s loop, 
and re-enter the cortical structure. This portion of the tube does not present a 
uniform calibre, but becomes narrower as it ascends, and irregular in outline. As 
a narrow tube it enters the cortex and ascends for a short distance, when it again 
becomes dilated, irregular, and angular. This section is termed the irregular tubule; 
it terminates in a convoluted tube which exactly resembles the proximal convoluted 
tubule, and is called the distal convoluted tubule. This again terminates in a narrow 
curved tube, which enters the straight or collecting tube. 948 
THE URINARY ORGANS. 
Each straight (otherwise called a collecting or receiving) tube commences by a 
small orifice on the summit of one of the papillae, thus opening and discharging its 
contents into the interior of one of the calices. Traced into the substance of the 
pyramid, these tubes are found to run from apex to base, dividing dichotomously in 
their course and slightly diverging from each other. Thus dividing and subdividing, 
they reach the base of the pyramid, and enter the cortical structure greatly increased 
in number. Upon entering the cortical portion they continue a straight course for a 
variable distance, and are arranged in groups called medullary rays, several of these 
groups corresponding to a single pyramid. The tubes in the centre of the group are 
the longest, and reach almost to the surface of the kidney, while the external ones 
are shorter, and advance only a short distance into the cortex. In consequence of 
this arrangement the cortical portion presents a number of conical masses, the apices 
of which reach the periphery of the organ, and the bases are applied to the medullary 
portion. These are termed the pyramids of Ferrein. As they run through the cor- 
tical portion the straight tubes receive on either side the curved extremity of the 
convoluted tubes, which, as stated above, commence at the Malpighian capsules. 
It will be seen from the above description that there is a continuous series of 
tubes from their commencement in the Malpighian capsules to their termination at 
the orifices on the apices of the pyramids of Malpighi, and that the urine, the secre- 
tion of which commences in the capsule, finds its way through these tubes into the 
calices of the kidney, and so into the ureter. Commencing at the capsule, the tube 
first presents a narrow constricted 
portion, the neck. 2. It forms a 
wide convoluted tube, the proxi- 
mal convoluted tube. 3. It be- 
comes spiral, the spiral tubule of 
Schachowa. 4. It enters the 
medullary structure as a narrow, 
straight tube, the descending 
limb of Henle's loop. 5. Form- 
ing a loop and becaming dilated, 
it ascends, somewhat spirally and 
gradually diminishing in calibre, 
and again enters the cortical 
structure, the ascending limb of 
Henle s loop. 6. It now be- 
comes irregular and angular in 
outline, the irregular tubule. 7. 
It then becomes convoluted, the 
distal convoluted tubule. 8. Di- 
minishing in size, it forms a 
curve, the curved tubule. 9. Fi- 
nally, it joins a straight tube, the 
straight collecting tube, which is 
continued downward through the 
medullary substance to open at 
the apex of a pyramid. 
The Tubuli Uriniferi: their 
Structure.-The tubuli uriniferi 
consist of basement-membrane 
lined with epithelium. The epi- 
thelium varies considerably in dif- 
ferent sections of the uriniferous tubes. In the neck the epithelium is continuous 
with that lining the Malpighian capsule, and like it consists of flattened cells with 
an oval nucleus (Fig. 629, a). The cells are, however, very indistinct and difficult 
to follow, and the tube has here the appearance of a simple basement-membrane 
unlined by epithelium. In the proximal convoluted tubule and the spiral tubule 
Fig. 629. 
CURVED 
COLLECTING 
TUBULE 
DISTAL 
CONVO- 
LUTED 
TUBULE 
\MALPIGHIAN 
A\ CORPUSCLE 
NECK'' 
PROXIMAL) , 
CONVOLUTED?' 
TUBULEj 
{IRREGULAR 
TUBULE 
SPIRAL TUBULE OFl 
6CHACHOWAJ 
SiPIRAL PART 
JF ASCENDING 
.1MB 
STRAIGHT) 
COLLECTING-? 
tube; 
DESCENDING LIMBA 
OF HENLE'S LOOPJ 
(ASCENDING 
l_LIM3 
Uriniferous Tube. For the sake of clearness the epithelial 
cells have been represented more highly magnified than 
the tubes in which they are contained. THE KIDNEYS. 
949 
of Schachowa the epithelium is polyhedral in shape, the sides of the cells not being 
straight, but fitting into each other, and in some animals so fused together that it is 
impossible to make out the lines of junction. In the human kidney the cells often 
present an angular projection of the surface next the basement-membrane. These 
cells are made up of more or less rod-like fibres, which rest by one extremity on 
the basement-membrane, whilst the other projects toward the lumen of the tube. 
This gives to the cells the appearance of distinct striation (Heidenhain) (Fig. 
629, b). In the descending limb of Henle's loop the epithelium resembles that 
found in the Malpighian capsule and the commencement of the tube, consisting of 
flat transparent epithelial plates with an oval nucleus (Fig. 629, a; Fig. 630). In the 
ascending limb, on the other hand, the cells partake more of the character of those 
described as existing in the proximal convoluted tubule, being polyhedral in shape 
and presenting the same appearance of striation. The nucleus, however, is not sit- 
uated in the centre of the cell, but near the lumen (Fig. 629, c). After the ascend- 
ing limb of Henle's loop becomes narrower upon entering the cortical structure, the 
striation appears to be confined to the outer part of the cell; at all events, it is much 
more distinct in this situation, the nucleus, which appears flattened and angular, being 
still situated near the lumen (Fig. 629, d). In the irregular tubule the cells undergo 
Fig. 631. 
Fig. 630.1 
Longitudinal Section of Henle's Descending Limb: a, 
membrana propria; b, epithelium. 
Longitudinal Section of Straight Tube: a, cylindrical 
or cubical epithelium; b, memhrana propria. 
a still further change, becoming very angular and presenting thick bright rods or 
markings, which render the striation much more distinct than in any other section 
of the urinary tubules (Fig. 629, h). In the distal convoluted tubule the epithe- 
lium appears to be identical with that which has been described as existing in the 
proximal convoluted tubule (Fig. 629, b). In the curved tubule, just before its 
entrance into the straight collecting tube, the epithelium varies greatly as regards 
the shape of the cells, some being angular with short processes, others spindle- 
shaped, others polyhedral (Fig. 629, e). 
In the straight tubes the epithelium is more or less columnar; in its papillary 
portion the cells are distinctly columnar and transparent (Figs. 631, 632); but as the 
tube approaches the cortex the cells are less uniform in shape ; some are polyhedral, 
and others angular with short processes (Fig. 629, F and g). 
The Renal Blood-vessels: their Origin, Course, and Distribution.-The kidney 
is plentifully supplied with blood by the renal artery, a large offset of the abdom- 
inal aorta, which enters the sinus through the hilum, dividing in its passage through 
the latter into four or five branches. [Quite frequently the kidney has two renal 
arteries, and occasionally more.] These whilst in the sinus give off a few twigs 
for the nutrition of the surrounding tissues, and terminate in the arterial propria 
1 From the Handbook for the Physiological Laboratory. THE URINARY ORGANS. 
950 
renales, which enter the kidney proper in the columns of Bertini. Two of these 
pass to each pyramid of Malpighi, and run along its sides for its entire length, 
giving off as they advance the afferent vessels of the Malpighian bodies in the col- 
Fig. 632. 
Transverse Section of Pyramidal Substance of Kidney of Pig, the blood-vessels of which are injected : a, large 
collecting tube, cut across, lined with cylindrical epithelium ; b, branch of collecting tube, cut across, lined 
with epithelium with shorter cylinders; c and d, Henle's loops, cut across; e, blood-vessels, cut across; d, 
connective-tissue ground-substance. 
umns. Having arrived at the bases of the pyramids, they make a bend in their 
course, so as to lie between the bases of the pyramids and the cortical arches, 
where they break up into two distinct sets of branches devoted to the supply of 
the remaining portions of the kidney. 
Fig. 633. 
Fro. 634. 
Diagrammatical Sketch of Kidney. 
A Portion of Fig. 633, enlarged (the references are 
the same). 
a, a, proper renal artery and vein, the former giving off the renal afferents, the latter receiving the renal effer- 
ents ; ft, b, interlobular artery and vein, the latter commencing from the stellate veins, and receiving 
branches from the plexus around the tubuli contorti, the former giving off renal afferents; c, straight tube, 
surrounded by tubuli contorti, with which it communicates, forming a pyramid of Ferrein, as more fully 
shown in Fig. 626; d, margin of medullary substance; e, e, e, receiving tubes, cut off; f, arteriolee et venee 
rectae, the latter arising from (g) the plexus at the medullary apex. 
The first set, the interlobular arteries (Figs. 633, 634, b), are given off at right 
angles from the side of the arterite proprise renales looking toward the cortical 
substance, and, passing directly outward between the pyramids of Ferrein, they THE KIDNEYS. 
951 
reach the capsule, where they terminate in the capillary network of this part. In 
their outward course they give off lateral branches; these are the afferent vessels 
for the Malpighian bodies (see p. 947), and, having pierced the capsule, end in the 
Malpighian tufts. From each tuft the corresponding renal efferent arises, which, 
having made its egress from the capsule near to the point where the afferent entered, 
anastomoses with other efferents from other tufts, and contributes to form a dense 
venous plexus around the adjacent urinary tubes (Fig. 635). 
The second set from the arteriae proprim renales are for the supply of the medul- 
lary pyramids, which they enter at their bases, and, passing straight through their 
substance to their apices, terminate in the venous 
plexuses found in that situation. They are called 
the arterioloe rectoe (Figs. 633, 634, f). 
The Renal Veins arise from three sources: the 
veins beneath the capsule, the plexuses around the 
tubuli contorti in the cortical arches, and the plex- 
uses situated at the apices of the pyramids of Mal- 
pighi. The veins beneath the capsule are stellate 
in arrangement, and are derived from the capil- 
lary network of the capsule, into which the ter- 
minal branches of the interlobular arteries break 
up. These join to form the vence interlobulares, 
which pass inward between the pyramids of Fer- 
rein, receive branches from the plexuses around 
the tubuli contorti, and, having arrived at the 
bases of the Malpighian pyramids, join with the 
venae rectae, next to be described (Figs. 633, 
634, 6). 
The Vence Rectce are branches from the plex- 
uses at the apices of the medullary pyramids, 
formed by the terminations of the arteriolae rectae. 
They pass outward in a straight course between 
the tubes of the medullary structure, and joining, 
as above stated, the venae interlobulares, form the proper renal veins (Figs. 633, 
634, /). 
These vessels, Vence Proprice Renales, accompany the arteries of the same name 
running along the entire length of the sides of the pyramids, and, having received 
in their course the efferents from the Malpighian bodies in the cortical structure 
adjacent, quit the kidney proper to enter the sinus. In this cavity they inosculate 
with the corresponding veins from the other pyramids to form the renal vein, which, 
passing through the hilum, opens into the inferior vena cava, the left being longer 
than the right, from having to cross in front of the abdominal aorta. 
Nerves of the Kidney.-The nerves of the kidney, although small, are about 
fifteen in number. They have small ganglia developed upon them, and are derived 
from the renal plexus, which is formed by branches from the solar plexus, the lower 
and outer part of the semilunar ganglion, and from the lesser and smallest splanch- 
nic nerves. They communicate with the spermatic plexus-a circumstance which 
may explain the sympathy that exists between the kidney and testicle. So far as 
they have been traced, they seem to accompany the renal artery and its branches, 
but their exact mode of termination is not known. 
The lymphatics consist of a superficial and deep set which terminate in the lum- 
bar glands. 
Connective Tissue, or Intertubular Stroma.-Although the tubules and vessels 
are closely packed, a certain small amount of connective tissue continuous with the 
capsule binds them firmly together. This tissue was first described by Goodsir, 
and subsequently by Bowman. Ludwig and Zawarykin have observed distinct 
fibres passing around the Malpighian bodies, and Henle has seen them between the 
straight tubes composing the medullary structure. 
Fig. 635. 
Diagrammatic Representation of the Blood- 
vessels in the Substance of the Cortex of 
the Kidney: m, region of the medullary 
ray; b, region of the tortuous portion of 
the tubules; ai, arteria interlobularis; 
vi, vena interlobularis; va, vas afferens; 
gl, glomerulus; ve, vas efferens; vz, venous 
twig of the interlobularis, (from Ludwig, 
in Stricker's Handbook). 952 
THE URINARY ORGANS. 
The Ureters. 
The Ureters are the two tubes which conduct the urine from the kidneys into 
the bladder. They commence within the sinus of the kidney by a number of short 
truncated branches, the calices or infundibula, which unite, either directly or indi- 
rectly, to form a dilated pouch, the pelvis, from which the ureter, after passing 
through the hilum of the kidney, descends to the bladder. The calices are cup- 
like tubes encircling the apices of the Malpighian pyramids; but inasmuch as one 
calyx may include two or even more papillae, their number is generally less than 
the pyramids themselves, the former being from seven to thirteen, whilst the latter 
vary from eight to eighteen. These calices converge into two or three tubular 
divisions, which by their junction form the pelvis, or dilated portion of the ureter. 
The portion last mentioned, where the pelvis merges into the ureter proper, is found 
opposite the spinous process of the first lumbar vertebra, in which situation it is 
accessible behind the peritoneum. (See Fig. 586, p. 884.) 
The ureter proper is a cylindrical membranous tube, from sixteen to eighteen 
inches in length and of the diameter of a goose-quill, extending from the pelvis of 
the kidney to the bladder. Its course is obliquely downward and inward through 
the lumbar region into the cavity of the pelvis, where it passes downward, forward, 
and inward across that cavity to the base of the bladder, into which it then opens 
by a constricted orifice, after having passed obliquely for nearly an inch between its 
muscular and mucous coats. 
Relations of the Ureter Proper.-In its course it rests upon the Psoas 
muscle, being covered by the peritoneum, and crossed obliquely, from within out- 
ward, by the spermatic vessels, the right ureter lying close to the outer side of the 
inferior vena cava. Opposite the first piece of the sacrum it crosses either the com- 
mon or external iliac artery, lying behind the ileum on the right side and the sig- 
moid flexure of the colon on the left. In the pelvis it enters the posterior false 
ligament of the bladder, below the obliterated hypogastric artery, the vas deferens 
in the male passing between it and the bladder. In the female the ureter passes 
along the sides and cervix of the uterus and upper part of the vagina. At the base 
of the bladder it is situated about two inches from its fellow, lying, in the male, 
about an inch and a half behind the base of the prostate, at the posterior angle of 
the trigone. 
Structure.-The ureter is composed of three coats-a fibrous, muscular, and 
mucous. 
The fibrous coat is the same throughout the entire length of the duct, being 
continuous at one end with the capsule of the kidney at the floor of the sinus, 
whilst at the other it is lost in the fibrous structure of the bladder. 
In the pelvis of the kidney the muscular coats are thick, but they become thin- 
ner and thinner in the calices, the longitudinal fibres becoming lost upon the sides 
of the mammillae, whilst a few scattered fibres from the circular layer may be traced 
surrounding the medullary structure in the same situation. In the ureter proper 
the muscular fibres are very distinct, and are arranged in three layers-an external 
longitudinal, a middle circular, and an internal layer less distinct than the other two, 
but having a general longitudinal direction. According to Kblliker, this internal 
layer is only found in the neighborhood of the bladder. 
The mucous coat is smooth and presents a few longitudinal folds which become 
effaced by distension. It is continuous with the mucous membrane of the bladder 
below, whilst it is prolonged over the mammillse of the kidney above. Its epithelium 
is of a peculiar character, and resembles that found in the bladder. It is known 
by the name of "transitional" epithelium. It consists of several layers of cells, 
of which the innermost-that is to say, the cells in contact with the urine-are 
quadrilateral in shape, with a concave margin on their outer surface, into which fits 
the rounded end of the cells of the second layer. These, the intermediate cells, 
more or less resemble columnar epithelium, and are pear-shaped, with a rounded 
internal extremity which fits into the concavity of the cells of the first layer, and a THE KIDNEYS. 
953 
narrow external extremity which is wedged in between the cells of the third layer. 
The external or third layer consists of conical or oval cells varying in number in 
different parts, and presenting processes which extend down into the basement 
membrane. 
The arteries supplying the ureter are branches from the renal, spermatic, internal 
iliac, and inferior vesical. 
The nerves are derived from the inferior mesenteric, spermatic, and hypogastric 
plexuses. 
Suprarenal Capsules. 
The suprarenal capsules were formerly classified together with the spleen, thy- 
mus, and thyroid under the head of "ductless glands," as they have no excretory 
duct. They are two small flattened glandular bodies, of a yellowfish color, situated 
at the back part of the abdomen, behind the peritoneum and immediately in front 
of the upper part of either kidney ; hence their name. The right one is somewhat 
triangular in shape, bearing a resemblance to a cocked hat; the left is more semi- 
lunar, and usually larger and higher than the right. They vary in size in differ- 
ent individuals, being sometimes so small as to be scarcely detected: their usual 
size is from an inch and a quarter to nearly two inches in length, rather less in 
width, and from two to three lines in thickness. In weight they vary from one to 
two drachms. 
Relations.-The anterior surface is in relation, on the right side, with the 
under surface of the liver, and on the left with the pancreas and spleen. The pos- 
terior surface rests upon the crus of the Diaphragm opposite the tenth dorsal ver- 
tebra. The upper thin convex border is directed upward and inward. The lower 
thick concave border rests upon the upper end of the kidney, to which it is con- 
nected by areolar tissue. The inner border is in relation with the great splanchnic 
nerves and semilunar ganglion, and lies in contact on the right side with the inferior 
vena cava, and on the left side with the aorta. The surface of the suprarenal gland 
is surrounded by areolar tissue containing much fat, and closely invested by a thin 
fibrous coat, which is difficult to remove on account of the numerous fibrous pro- 
cesses and vessels which enter the organ through the furrows on its anterior surface 
and base. 
Structure.-On making a perpendicular section the gland is seen to consist of 
two substances-external or cortical, and internal or medullary. The former, which 
constitutes the chief part of the organ, is of a deep-yellow color, and consists chiefly 
of narrow columnar masses placed perpendicularly to the surface. The medullary 
substance is soft, pulpy, and of a dark-brown or black color, whence the name 
atrabiliary capsules formerly given to these organs. In the centre is often seen a 
space, not natural, but formed by the breaking down after death of the medullary 
substance. 
The cortical portion owes its arrangement to the disposition of the capsule, 
which sends into the interior of the gland processes passing in vertically and com- 
municating with each other by transverse bands, so as to form spaces which open 
into each other. These spaces are of slight depth near the surface of the organ, so 
that there the section somewhat resembles a net; this is termed the zona glomerulosa, 
but they become much deeper or longer farther in, so as to resemble pipes or tubes 
placed endwise, the zona fasciculata. Still deeper down, near the medullary part, 
the spaces become again of small extent; this is named the zona reticularis. These 
processes or trabeculse, derived from the capsule and forming the framework of 
the spaces, are composed of fibrous connective tissue, with longitudinal bundles of 
unstriped muscular fibres. Within the interior of the spaces are contained groups 
of polyhedral cells, which are finely granular in appearance and contain a spherical 
nucleus, and not unfrequently fat-molecules. These groups of cells do not entirely 
fill the spaces in which they are contained, but between them and the trabeculae of 
the framework is a channel which is believed to be a lymph-path or sinus, and 
which communicates with certain passages between the cells composing the group. 954 
THE URINARY ORGANS. 
The lymph-path is supposed to open into a plexus of efferent lymphatic vessels 
which are contained in the capsule. 
In the medullary portion the fibrous stroma seems to be collected together into 
a much closer arrangement, and forms 
bundles of connective tissue which 
are loosely applied to the large plex- 
us of veins of which this part of the 
organ mainly consists. In the inter- 
stices lie a number of cells compared 
by Frey to those of columnar epi- 
Fig. 636. 
Fig. 637. 
Vertical Section of the Suprarenal Capsule (from Elberth, in 
Stricker's Manual): 1, Cortical substance; 2, medullary sub- 
stance ; a, capsule; b, zona glomerulosa; c, zona fascicu- 
lata; d, zona reticularis; e, medulla; f, a large vein. 
Cortical Portion of Human Suprarenal Body, 
under a high magnifying power: a, gland- 
cylinders ; b, interstitial connective tissue. 
thelium. They are coarsely granular, do not contain any fat-molecules, and some 
of them are branched. Luschka has affirmed that 
these branches are connected with the nerve-fibres of 
a very intricate plexus which is found in the me- 
dulla : this statement has not been verified by other 
observers, for the tissue of the medullary substance 
is less easy to make out than that of the cortical, 
owing to its rapid decomposition. 
The numerous arteries which enter the suprarenal 
bodies from the sources mentioned below penetrate 
the cortical part of the gland, where they break up 
into capillaries in the fibrous septa, and these con- 
verge to the very numerous veins of the medullary 
portion, which are collected together into the supra- 
renal vein, which usually emerges as a single vessel 
from the centre of the gland. 
The arteries supplying the suprarenal capsules 
are numerous and of large size; they are derived 
from the aorta, the phrenic, and the renal; they 
subdivide into numerous minute branches previous 
to entering the substance of the gland. 
The suprarenal vein returns the blood from the medullary venous plexus, and 
Fig. 638. 
Transverse Section through the Cortical 
Substance of the Human Suprarenal 
Body: a, framework of connective 
tissue; b, capillaries; c, nuclei; d, 
gland-cells. THE PELVIS. 
955 
receives several branches from the cortical substance; it opens on the right side into 
the inferior vena cava, on the left side into the renal vein. 
The lymphatics terminate in the lumbar glands. 
The nerves are exceedingly numerous: they are found chiefly, if not entirely, in 
the medulla, and are derived from the solar and renal plexuses, and, according to 
Bergmann, from the phrenic and pneumogastric nerves. They have numerous small 
ganglia developed upon them, from which circumstance the organ has been conjec- 
tured to have some function in connection with the sympathetic nervous system. 
THE PELVIS. 
The cavity of the pelvis is that part of the general abdominal cavity which is 
below the level of the linea ilio-pectinea and the promontory of the sacrum. 
Boundaries.-It is bounded behind by the sacrum, the coccyx, and the great 
sacro-sciatic ligaments; in front and at the sides by the pubes and ischia, covered 
by the Obturator muscles; above it communicates with the cavity of the abdomen; 
and below it is limited by the triangular ligament, the Levatores ani and Coccygei 
muscles, and the visceral layer of the pelvic fascia, which is reflected from the wall 
of the pelvis on to the viscera. 
Contents.-The viscera contained in this cavity are the urinary bladder, the rec- 
tum, and some of the generative organs peculiar to each sex: they are partially 
covered by the peritoneum, and supplied with blood-vessels, lymphatics, and nerves. 
The Bladder. 
The Bladder is the reservoir for the urine. It is a musculo-membranous sac 
situated in the pelvis, behind the pubes, and in front of the rectum in the male, 
the uterus and vagina intervening between it and that intestine in the female. The 
shape, position, and relations of the bladder are greatly influenced by age, sex, and 
the degree of distension of the organ. During infancy it is conical in shape and 
projects above the upper border of the pubes into the hypogastric region. In the 
adult, when quite empty and contracted, it is a small triangular sac placed deeply 
in the pelvis, flattened from before backward, its apex reaching as high as the upper 
border of the symphysis pubis. When slightly distended it has a rounded form, and 
is still contained within the pelvic cavity; and when greatly distended it is ovoid in 
shape, rising into the abdominal cavity and often extending nearly as high as the 
umbilicus. It is larger in its vertical diameter than from side to side, and its long 
axis is directed from above obliquely downward and backward, in a line directed 
from some point between the pubes and umbilicus (according to its distension) to 
the end of the coccyx. The Bladder when distended is slightly curved forward 
toward the anterior wall of the abdomen, so as to be more convex behind than in 
front. In the female it is larger in the transverse than in the vertical diameter, 
and its capacity is said to be greater than in the male.1 When moderately distended 
it measures about five inches in length and three inches across, and the ordinary 
amount which it contains is about a pint. 
The bladder is divided into a summit, body, base, and neck. 
The summit or apex of the bladder is rounded and directed forward and upward; 
it is connected to the umbilicus by a fibro-muscular cord, the urachus, and also by 
means of two rounded fibrous cords, the obliterated portions of the hypogastric arte- 
ries, which are placed one on each side of the urachus. The summit of the bladder 
behind the urachus is covered by peritoneum, whilst the portion in front of the 
urachus has no peritoneal covering, but rests against the abdominal wall. 
The Urachus is the obliterated remains of a tubular canal which exists in the 
embryo, and connects the cavity of the bladder with a membranous sac placed 
external to the abdomen opposite the umbilicus, called the allantois. In the infant 
1 According to Henle, the bladder is considerably smaller in the female than in the male. THE URINARY ORGANS. 
956 
at birth it is occasionally found pervious, so that the urine escapes at the umbilicus, 
and calculi have been found in its canal. 
The body of the bladder in front is not covered by peritoneum, and is in rela- 
tion with the triangular ligament, the posterior surface of the symphysis pubis, the 
Internal obturator muscles, and, when distended, with the abdominal parietes. 
[The amount of space above the pubes uncovered by peritoneum, through which 
access may be had to the bladder for exploration or operation, varies very much. 
Fig. 639. 
Qi.nu.3 
or Utriculus 
Cowpor'a Gland-' 
vertical Section of Bladder, Penis, and Urethra. [Compare with Fig. 682, p. 1022.] 
Prepuce 
When the bladder is empty, there is none, as the bladder then sinks into the pelvis; 
when it is distended, the degree to which the peritoneum is lifted above the pubes 
depends on the degree of distension. This will amount to one to two inches, and if 
need be can be increased by stripping the peritoneum off the bladder to some extent. 
The bladder can also be lifted still farther and made more accessible by inserting a 
rubber bag into the rectum and distending it with water. Not over ten ounces should 
be used in the rectal bag, lest rupture take place; and for a similar reason rather 
less should be used in distending the bladder. The student, if possible, should 
distend both of these viscera experimentally both before and after opening the 
abdomen.] 
The posterior surface is covered by peritoneum throughout. It corresponds, in 
the male with the rectum; in the female with the uterus, some convolutions of the 
small intestine being interposed. 
The side of the bladder is crossed obliquely from below, upward, and forward by 
the obliterated hypogastric artery: above and behind this cord the bladder is cov- 
ered by peritoneum, but below and in front of it the serous covering is wanting, 
and it is connected to the pelvic fascia. The vas deferens passes in an arched direc- 
tion from before backward along the side of the bladder, toward its base, crossing 
in its course the obliterated hypogastric artery and passing along the inner side of 
the ureter. THE PELVIS. 
957 
The base (fundus) of the bladder is directed downward and backward. It varies 
in extent according to the state of distension of the organ, being very broad when 
full, but much narrower when empty. Tn the male it rests upon the second portion 
of the rectum, from which it is separated by a reflection of the recto-vesical fascia. 
It is covered posteriorly, for a slight extent, by the peritoneum, which is reflected 
from it upon the rectum, forming the recto-vesical fold. The portion of the bladder 
in relation with the rectum corresponds to a triangular space bounded behind by the 
recto-vesical fold, on either side by the vesicula seminalis and vas deferens, and 
touching the prostate gland in front. When the bladder is very full the peritoneal 
fold is raised with it, and the distance between its reflection and the anus is about 
four inches; but this distance is much diminished when the bladder is empty and 
■contracted. In the female the base of the bladder lies in contact with the lower 
part of the cervix uteri, is adherent to the anterior wall of the vagina, and is sepa- 
rated from the upper part of the anterior surface of the cervix uteri by a fold of the 
peritoneum. 
The neck (cervix) of the bladder is the constricted portion continuous with the 
urethra. In the male its direction is oblique in the erect posture, and it is sur- 
rounded by the prostate gland. In the female its direction is obliquely downward 
and forward. 
Ligaments.-The bladder is retained in its place by ligaments which are divided 
into true and false. The true ligaments are five in number-two anterior and two 
lateral, formed by the recto-vesical fascia and the urachus. The false ligaments, 
also five in number, are formed by folds of the peritoneum. 
The anterior ligaments (pubo-prostatic) extend from the back of the pubes, one 
on each side of the symphysis, to the front of the neck of the bladder, over the 
upper surface of the prostate gland. These ligaments contain a few muscular fibres 
prolonged from the bladder. 
The lateral ligaments, broader and thinner than the preceding, are attached to 
the lateral parts of the prostate and to the sides of the base of the bladder. 
The urachus is the fibro-muscular cord already mentioned extending between the 
summit of the bladder and the umbilicus. It is broad below at its attachment to the 
bladder, and becomes narrower as it ascends. 
The false ligaments of the bladder are two posterior, two lateral, and one 
superior. 
The two posterior pass forward, in the male, from the sides of the rectum; in 
the female, from the sides of the uterus to the posterior and lateral aspect of the 
bladder: they form the lateral boundaries of the recto-vesical fold of the perito- 
neum, and contain the obliterated hypogastric arteries and the ureters, together with 
vessels and nerves. 
The two lateral ligaments are reflections of the peritoneum from the iliac fossae 
to the sides of the bladder. 
The superior ligament is the prominent fold of peritoneum extending from the 
summit of the bladder to the umbilicus. It covers the urachus and the obliterated 
hypogastric arteries. 
Structure.-The bladder is composed of four coats-a serous, a muscular, a sub- 
mucous, and a mucous coat. 
The serous coat is partial, and derived from the peritoneum. It invests the pos- 
terior surface from opposite the termination of the two ureters to its summit, and is 
reflected from this point and from the sides on to the abdominal and pelvic walls. 
The muscular coat consists of three layers of unstriped muscular fibre: an exter- 
nal layer, composed of fibres having for the most part a longitudinal arrangement; 
a middle layer, in which the fibres are arranged more or less in a circular manner; 
and an internal layer, in which the fibres have a general longitudinal arrangement. 
The fibres of the external longitudinal layer arise from the posterior surface of 
the body of the pubes in both sexes (mwscuZz pubo-vesiculis), and in the male from 
the adjacent part of the prostate gland and its capsule. They pass in a more or less 
longitudinal manner up the anterior surface of the bladder, over its apex, and then 958 
THE URINARY ORGANS. 
descend along its posterior surface to its base, where they become attached to the 
prostate in the male and to the front of the vagina in the female. At the sides of 
the bladder the fibres are arranged obliquely and intersect one another. This layer 
has been named the detrusor urince muscle. 
The middle circular layers are very thinly and irregularly scattered on the body 
of the organ, and, though to some extent placed transversely to the long axis of the 
bladder, are for the most part arranged obliquely. Toward the lower part of the 
Fig. 640. 
Fig. 641. 
Deep Layers of Epithelium of Bladder, 
showing large club-shaped cells above, 
and smaller, more spindle-shaped cells 
below, each with an oval nucleus (Klein 
and Noble Smith). 
Superficial Layer of the Epithelium of the Bladder, 
composed of polyhedral cells of various sizes, each 
with one, two, or three nuclei (Klein and Noble 
Smith). 
bladder, round the cervix and commencement of the urethra, they are disposed in 
a thick circular layer, forming the sphincter vesicce, which is continuous with the 
muscular fibres of the prostate gland. Pettigrew has described these two layers as 
forming a series of figure-of-8 spiral loops. 
The internal longitudinal layer is thin and its fasciculi have a reticular arrange- 
ment, but with a tendency to assume for the most part a longitudinal direction. 
Two bands of oblique fibres, originating behind the orifices of the ureters, con- 
verge to the back part of the prostate gland, and are inserted by means of a fibrous 
process into the middle lobe of that organ. They are tlie muscles of the ureters, 
described by Sir C. Bell, who supposed that during the contraction of the bladder 
they served to retain the oblique direction of the ureters, and so prevent the reflux 
of the urine into them. 
The submucous coat consists of a layer of areolar tissue connecting together the 
muscular and mucous coats, and intimately united to the latter. 
The mucous coat is thin, smooth, and of a pale rose color. It is continuous 
through the ureters with the lining membrane of the uriniferous tubes, and below 
with that of the urethra. It is connected loosely to the muscular coat by a layer 
of areolar tissue, excepting at the trigone, where its adhesion is more close. It is 
provided with a few mucous follicles, and numerous small racemose glands, lined 
with columnar epithelium, exist near the neck of the organ. The epithelium cov- 
ering it is of the transitional variety, consisting of a superficial layer of polyhedral, 
flattened cells, each with one, two, or three nuclei; beneath these a stratum of 
large club-shaped cells, with the narrow extremity directed downward and wedged 
in between smaller spindle-shaped cells, containing an oval nucleus (Figs. 640, 641). 
Interior of the Bladder.-Upon the inner surface of the base of the bladder, 
immediately behind the urethral orifice, is a triangular, smooth surface, the apex of 
which is directed forward ; this is the trigonum vesicce or trigone vesical. It is paler 
in color than the rest of the mucous membrane, and never presents any rugae, even 
in the collapsed condition of the organ, owing to its intimate adhesion to the subja- 
cent tissue. It is bounded at each posterior angle by the orifices of the ureters, 
which are placed nearly two inches from each other and about an inch and a half 
behind the orifice of the urethra. The trigone corresponds, with the interval at the 
base of the bladder, bounded by the prostate in front and the vesiculae and vasa 
deferentia on the sides. Projecting from the lower and anterior part of the blad- THE PELVIS. 
959 
der into the orifice of the urethra is a slight elevation of mucous membrane called 
the uvula vesicce. It is formed by a thickening of the prostate. 
The arteries supplying the bladder are the superior, middle, and inferior vesical 
in the male, with additional branches from the ute- 
rine and vaginal in the female. They are all de- 
rived from the anterior trunk of the internal iliac. 
The obturator and sciatic arteries also supply small 
visceral branches to the bladder. 
The veins form a complicated plexus round the 
neck, sides, and base of the bladder, and terminate 
in the internal iliac vein. 
The lymphatics accompany the blood-vessels, 
passing through the glands surrounding them. 
The nerves are derived from the hypogastric 
plexus of the sympathetic and the fourth sacral 
nerve, the former supplying the upper part of the 
organ, the latter its base and neck. According 
to F. Darwin, the sympathetic fibres have ganglia 
connected with them which send branches to the 
vessels and muscular coat. 
Fig. 642. 
Male Urethra. 
fjowpefs Gland 
The Urethra extends from the neck of the 
bladder to the meatus urinarius. It presents a 
double curve in the flaccid state of the penis, but 
in the erect state it forms only a single curve, the 
concavity of which is directed upward (Fig. 639, 
p. 956). Its length varies from eight to nine 
inches, and it is divided into three portions, the 
prostatic, membranous, and spongy, the structure 
and relations of which are essentially different. 
The prostatic portion is the widest and most 
dilatable part of the canal. It passes through the 
prostate gland from its base to its apex, lying 
nearer its upper than its lower surface. It is 
about an inch and a quarter in length; the form 
of the canal is spindle-shaped, being wider in the 
middle than at either extremity, and narrowest in 
front, where it joins the membranous portion. A 
transverse section of the canal as it lies in the 
prostate is horseshoe in shape, the convexity be- 
ing directed upward (Fig. 644, p. 962). The canal is closed except during the pas- 
sage of the urine, the upper and lower mucous surfaces being in contact. 
Upon the floor of the canal is a narrow longitudinal ridge, the verumontanum or 
caput gallinaginis, formed by an elevation of the mucous membrane and its subja- 
cent tissue. It is eight or nine lines in length and a line and a half in height, and 
contains, according to Kobelt, muscular and erectile tissues. When distended it 
may serve to prevent the passage of the semen backward into the bladder. On each 
side of the verumontanum is a slightly depressed fossa, the prostatic sinus, the floor 
of which is perforated by numerous apertures, the orifices of the prostatic ducts, the 
ducts of the middle lobe opening behind the crest. At the fore part of the veru- 
montanum, in the middle line, is a depression, the sinus pocularis (vesicula. prostat- 
icd), and upon or within its margins are the slit-like openings of the ejaculatory 
ducts. The sinus pocularis forms a cul-de-sac about a quarter of an inch in length 
which runs upward and backward in the substance of the prostate beneath the mid- 
dle lobe; its prominent upper wall partly forms the verumontanum. Its walls are 
Orifices of 
of Causers Glands 
The Bladder and Urethra, laid open, seen 
from above. 
Meatu? 960 
T1IE URINARY ORGANS. 
composed of fibrous tissue, muscular fibres, and mucous membrane, and numerous 
small glands open on its inner surface. It has been called by Weber, who discovered 
it, the uterus masculinus, from its homology with the female organ. 
The membranous portion of the urethra extends between the apex of the pros- 
tate and the bulb of the corpus spongiosum. It is the narrowest part of the canal 
(excepting the orifice), and measures three-quarters of an inch along its upper and 
half an inch along its lower surface, in consequence of the bulb projecting backward 
beneath it below. Its upper concave surface is placed about an inch beneath the 
pubic arch, from which it is separated by the dorsal vessels and nerves of the penis 
and some muscular fibres. Its lower convex surface is separated from the rectum 
by a triangular space which constitutes the perineum. The membranous portion of 
the urethra perforates both the anterior and posterior layers of the deep perineal 
fascia, and receives an investment from them. As it pierces the posterior layer, the 
fibres around the opening are prolonged backward over the posterior part of the 
membranous portion of the urethra; and as it pierces the anterior layer, a similar 
prolongation takes place in the opposite direction, investing the anterior part of the 
membranous portion. It is also surrounded by the Compressor urethrae muscle. 
The spongy [or penile] portion is the longest part of the urethra, and is con- 
tained in the corpus spongiosum. It is about six inches in length, and extends 
from the termination of the membranous portion to the meatus urinarius. Com- 
mencing below the symphysis pubis, it ascends for a short distance and then curves 
downward. It is narrow and of uniform size in the body of the penis, measuring 
about a quarter of an inch in diameter, being dilated behind within the bulb ; and 
again anteriorly, within the glans penis, forming the fossa navicularis. A cross- 
section of this canal in the body of the penis has its long diameter transverse, but 
in the glans that diameter is directed vertically. 
The bulbous portion is a name given in some descriptions of the urethra to the 
posterior part of the spongy portion contained within the bulb. 
The meatus urinarius is the most contracted part of the urethra; it is a vertical 
slit about three lines in length, bounded on each side by two small labia. 
[The calibre of the urethra has generally been placed much too low. In the aver- 
age adult, when its walls are separated, it is f of an inch in diameter (about 9 milli- 
meters (No. 27) of the French catheter 
scale). It has two points of marked 
narrowing as to dilatability-at the 
meatus and the triangular ligament; 
and three of decided dilatation-at 
the fossa navicularis and the bulbous 
and prostatic portions.] 
The inner surface of the lining 
membrane of the urethra, especially 
on the floor of the spongy portion, 
presents the orifices of numerous 
mucous glands and follicles situated in the submucous tissue, and named the glands 
of Littre. They vary in size, and their orifices are directed forward, so that they 
may easily intercept the point of a catheter in its passage along the canal; espe- 
cially the largest one of these lacunae, which is situated on the upper surface of the 
fossa navicularis, about an inch and a half from the orifice; it is called the lacuna 
magna. Into the bulbous portion are found opening the ducts of Cowper's glands.1 
Structure.-The urethra is composed of a continuous mucous membrane sup- 
ported by a submucous tissue which connects it with the various structures through 
which it passes. 
The mucous coat forms part of the genito-urinary mucous membrane. It is con- 
tinuous with the mucous membrane of the bladder, ureters, and kidneys, externally 
[Fig. 643. 
Diagram of Urethra in Natural Condition, a, b, and c repre- 
senting the prostatic, membranous, and spongy portions 
respectively (Thompson).] 
1 The student should bear in mind that though the urethra is described as a tube, it is not so in 
reality, but is a mere cleft; and that the canal is closed and the opposite mucous surfaces in contact 
except during the passage of the urine or semen. THE PELVIS. 
961 
with the integument covering the glans penis, and is prolonged into the ducts of the 
glands which open into the urethra-viz. Cowper's glands, the prostate gland, and 
the vasa deferentia and vesiculm seminales-through the ejaculatory ducts. In the 
spongy and membranous portions the mucous membrane is arranged in longitudinal 
folds when the organ is contracted. Small papillae are found upon it near the ori- 
fice, and its epithelial lining is of the columnar variety, excepting near the meatus, 
where it is laminated. 
The submucous tissue consists of plain muscular fibre, mixed with fibrous and 
elastic tissue. The muscular fibres are arranged in two layers, the inner layer being 
disposed longitudinally, and the outer in a circular direction. Ellis has demonstrated 
that the longitudinal fibres are continuous with the internal longitudinal muscular 
fibres of the bladder. The amount of muscular tissue differs in different parts of 
the canal. It is greatest in quantity in the prostatic portion, becomes diminished 
in amount in the membranous portion, and almost replaced by fibrous tissue in the 
spongy portion. In the prostatic and membranous parts of the urethra there is also 
a thin enveloping layer of erectile tissue. 
[The cleft of the urethra (Fig. 645) is horizontal, except toward the bladder, 
where it is arched (Fig. 644), and toward the meatus, where it becomes vertical.] Male Generative Organs. 
PROSTATE GLAND. 
THE Prostate Gland (itpotOTTjpu, to stand before) is a pale, firm, glandular body 
which surrounds the neck of the bladder and commencement of the urethra. 
It is placed in the pelvic cavity behind and below the symphysis pubis posterior to 
the deep perineal fascia, and upon the rectum, through which it may be distinctly 
felt, especially when enlarged. In shape and size it resembles a chestnut. 
Fig. 644. 
Transverse Section of the Prostate Gland, showing the urethra (1), arching over the eminence of the caput gal- 
linaginis; beneath it the sinus pocularis (2) and ejaculatory ducts (3). 
Its base is directed backward toward the neck of the bladder. 
The apex is directed forward to the deep perineal fascia, which it touches. 
Its under surface is smooth and rests on the rectum, to which it is connected by 
dense areolar fibrous tissue. 
Its upper surface is flattened, marked by a slight longitudinal furrow, and placed 
about three-quarters of an inch below the pubic symphysis. 
It measures about an inch and a half in its transverse diameter at the base, an 
inch in its antero-posterior diameter, and three-quarters of an inch in depth. Its 
weight is about six drachms. It is held in its position by the anterior ligaments 
of the bladder (pub o-pro static) ; by the posterior layer of the deep perineal fascia, 
which invests the commencement of the membranous portion of the urethra and 
prostate gland; and by the anterior portion of the Levator ani muscle (levator 
prostates), which passes down on each side from the symphysis pubis and anterior 
ligament of the bladder to the sides of the prostate. 
The prostate consists of two lateral lobes and a middle lobe. 
962 COWPER'S GLANDS. 
963 
The two lateral lobes are of equal size, separated behind by a deep notch, and 
marked by a slight furrow upon their upper and lower surfaces, which indicates the 
bilobed condition of the organ in some animals. 
The third or middle lobe is a small transverse band, occasionally a rounded or 
triangular prominence, placed between the two lateral lobes at the under and pos- 
terior part of the organ. It lies immediately beneath the neck of the bladder, 
behind the commencement of the urethra, and above and between the ejaculatory 
ducts. Its existence is not constant, but it is occasionally found at an early period 
of life, as well as in adults and in old age. In advanced life this or some other 
portion of the prostate often becomes considerably enlarged, and projects into the 
bladder, so as to impede the passage of the urine. According to Dr. Messer's 
researches, conducted at Greenwich Hospital,1 it would seem that such obstruction 
exists in 20 per cent, of all prostates over sixty years of age. 
The prostate gland is perforated by the urethra and common seminal ducts. The 
urethra usually lies about one-third nearer its upper than its lower surface; occasion- 
ally the prostate surrounds only the lower three-fourths of this tube, and more rarely 
the urethra runs through the lower instead of the upper part of the gland. The ejac- 
ulatory ducts pass forward obliquely through a conical canal situated in the lower part 
of the prostate and open into the prostatic portion of the urethra. 
Structure.-The prostate is enclosed in a thin but firm fibrous capsule distinct 
from that derived from the posterior layer of the deep perineal fascia, and separated 
from it by a plexus of veins. Its substance is of a pale reddish-gray color, very 
friable, but of great density. It consists of glandular substance and muscular 
tissue. 
The muscular tissue, according to Kolliker, constitutes the proper stroma of the 
prostate, the connective tissue being very scanty, and simply forming thin trabec- 
ulae between the muscular fibres in which the vessels and nerves of the gland ram- 
ify. The muscular tissue is arranged as follows: Immediately beneath the fibrous 
capsule is a dense layer which forms an investing sheath for the gland; secondly, 
around the urethra as it lies in the prostate is another dense layer of circular fibres, 
continuous behind with the internal layer of the muscular coat of the bladder, and 
in front blending with the fibres surrounding the membranous portion of the 
urethra. Between these two layers strong bands of muscular tissue, which decus- 
sate freely, form meshes in which the glandular structure of the organ is imbedded. 
In that part of the gland which is situated anterior to the urethra the muscular 
tissue is especially dense, and there is here little or no gland-tissue; while in that 
part which is behind the urethra the muscular tissue presents a wide-meshed struc- 
ture, which is densest at the upper part of the gland-that is, near the bladder- 
becoming looser and more sponge-like toward the apex of the organ. 
The glandidar substance is composed of numerous follicular pouches opening 
into elongated canals, which join to form from twelve to twenty small excretory 
ducts. The follicles are connected together by areolar tissue, supported by prolon- 
gations from the fibrous capsule and muscular stroma and enclosed in a delicate 
capillary plexus. The epithelium lining both the canals and the terminal vesicles 
is of the columnar variety. The prostatic ducts open into the floor of the prostatic 
portion of the urethra. 
Vessels and Nerves.-The arteries supplying the prostate are derived from 
the internal pudic, vesical, and hemorrhoidal. Its veins form a plexus around the 
sides and base of the gland; they receive in front the dorsal vein of the penis and 
terminate in the internal iliac vein. The nerves are derived from the hypogastric 
plexus. 
COWPER'S GLANDS 
Cowper's Glands are two small rounded and somewhat tabulated bodies, of a 
yellow color, about the size of peas, placed beneath the fore part of the membran- 
Med.-Chir. Trans., vol. xliii. p. 152. 964 
MALE GENERATIVE ORGANS. 
ous portion of the urethra, between the two layers of the deep perineal fascia. They 
lie close behind the bulb, and are enclosed by the transverse fibres of the Compressor 
urethrae muscle. Each gland consists of several lobules, held together by a fibrous 
investment. Each lobule consists of a number of acini, lined by clear columnar 
cells, opening into one common duct, which, joining with the ducts of other lobules 
outside the gland, form a single excretory duct. The excretory duct of each gland, 
nearly an inch in length, passes obliquely forward beneath the mucous membrane, 
and opens by a minute orifice on the floor of the bulbous portion of the urethra. 
Their existence is said to be constant; they gradually diminish in size as age 
advances. 
THE PENIS. 
The Penis [Figs. 639, p. 956, and 682, p. 1022] is the organ of copulation, and 
contains in its interior the larger portion of the urethra. It consists of a root, body, 
and extremity, or glans penis. 
The root, is broad, and firmly connected to the rami of the pubes by two strong 
tapering fibrous processes, the crura, and to the front of the symphysis pubis by a 
fibrous membrane, the suspensory ligament. 
The extremity, or glans penis, presents the form of an obtuse cone flattened from 
above downward. At its summit is a vertical fissure, the orifice of the urethra 
(meatus urinarius); at the back part of this orifice a 
fold of mucous membrane passes backward to the bot- 
tom of a depressed raphe, where it is continuous with 
the prepuce; this fold is termed the frcenum prceputii. 
The base of the glans forms a rounded projecting bor- 
der, the corona glandis, and behind the corona is a deep 
constriction, the cervix. Upon both of these numerous 
small lenticular sebaceous glands are found, the glandu- 
Ice Tysonii odoriferce. They secrete a sebaceous matter 
of very peculiar odor, which probably contains caseine 
and becomes easily decomposed. 
The body of the penis is the part between the root 
and extremity. In the flaccid condition of the organ it 
is cylindrical, but when erect has a triangular prismatic 
form with rounded angles, the broadest side being turned 
upward and called the dorsii/m. It is covered by integ- 
ument remarkable for its thinness, its dark color, its looseness of connection with 
the deeper parts of the organ, and its containing no adipose tissue. At the root of 
the penis the integument is continuous with that upon the pubes and scrotum ; and 
at the neck of the glans it leaves the surface and becomes folded upon itself to form 
the prepuce. 
The internal layer of the prepuce is attached behind to the cervix, and approaches 
in character to a mucous membrane; from the cervix it is reflected over the glans 
penis, and at the meatus urinarius is continuous with the mucous lining of the 
urethra. 
The mucous membrane covering the glans penis contains no sebaceous glands, 
but projecting from its free surface are a number of small highly sensitive papillae. 
The penis is composed of a mass of erectile tissue enclosed in three cylindrical 
fibrous compartments. Of these, two, the corpora cavernosa, are placed side by 
side along the upper part of the organ; the third, or corpus spongiosum, encloses 
the urethra, and is placed below. 
The Corpora cavernosa form the chief part of the body of the penis. They 
consist of two fibrous cylindrical tubes, placed side by side and intimately connected 
along the median line for their anterior three-fourths, whilst at their back part they 
separate from each other to form two tapering processes, named crura, which are 
connected to the rami of the pubes and ischium. Each crus commences by a blunt- 
[Fig. 645. 
Cross-section of Penis: 1, Dorsal 
vein; 2, dorsal arteries; 3, corpus 
cavernosum; 4, tunica albuginea; 
5, skin ; 6, corpus spongiosum in 
its tunica albuginea; 7, urethra 
(Cruveilhier).] THE PENIS. 
965 
pointed process in front of the tuberosity of the ischium, and near its junction with 
its fellow presents a slight enlargement, named by Kobelt the bulb of the corpus 
cavernosum. Just beyond this point they become constricted, and retain an equal 
diameter to their anterior extremity, where they form a single rounded end, which 
is received into a fossa in the base of the glans penis. A median groove on the 
upper surface lodges the dorsal vein of the penis, and the groove on the under sur- 
face receives the corpus spongiosum. The root of the penis is connected to the 
symphysis pubis by the suspensory ligament. 
Structure.-The corpora cavernosa are surrounded by a strong fibrous envelope 
consisting of two sets of fibres; the one, internal, being circular in direction, and 
being proper to each corpus cavernosum; the other, longitudinal in direction, being 
common to the two corpora cavernosa and investing them in a common covering. 
The internal circular fibres by their junction at one part form an incomplete par- 
tition or septum between the two bodies. This fibrous investment is extremely 
dense, of considerable thickness, and consists of bundles of shining white fibres, 
with an admixture of well-developed elastic fibres, so that it is possessed of great 
elasticity. 
The septum between the two corpora cavernosa forms an imperfect partition; it 
is thick and complete behind, but in front it is incomplete, and consists of a num- 
ber of vertical bands which are arranged like the teeth of a comb, whence the name 
which it has received, septum, pectiniforme. These bands extend between the dorsal 
and the urethral surface of the corpora cavernosa. 
From the internal surface of the fibrous envelope, as well as from the sides of 
the septum, are given off a number of bands or cords which cross the interior of 
the corpora cavernosa in all directions, subdividing them into a number of separate 
compartments and giving the entire structure a spongy appearance. These bands 
and cords are called trabeculce, and consist of white fibrous tissue, elastic fibres, and 
plain muscular fibres. In them are contained numerous arteries and nerves. 
The component fibres of which the trabeculae are composed are larger and 
stronger round the circumference than at the centre of the corpora cavernosa; they 
are also thicker behind than in front. The interspaces, on the contrary, are larger 
at the centre than at the circumference, their long diameter being directed trans- 
versely ; they are largest anteriorly. They are occupied by venous blood, and are 
lined by a layer of flattened cells similar to the endothelial lining of veins. 
The whole of the structure of the corpora cavernosa contained within the fibrous 
sheath consists, therefore, of a sponge-like tissue of areolar spaces freely communi- 
cating with each other and filled with venous blood. The spaces may therefore be 
regarded as large cavernous veins. 
The arteries bringing the blood to these spaces are the arteries of the corpora 
cavernosa and branches from the dorsal artery of the penis, which perforate the 
fibrous capsule along the upper surface, especially near the fore part of the organ. 
These arteries on entering the cavernous structure divide into branches, which 
are supported and enclosed by the trabeculae. Some of these terminate in a capil- 
lary network, the branches of which open directly into the cavernous spaces; others 
assume a tendril-like appearance, and form convoluted and somewhat dilated vessels, 
which were named by Muller helicene arteries. They project into the spaces, and 
from them are given off small capillary branches to supply the trabecular structure. 
They are bound down in the spaces by fine fibrous processes, and are more abundant 
in the back part of the corpora cavernosa. 
The blood from the cavernous spaces is returned by a series of vessels, some of 
which emerge in considerable numbers from the base of the glans penis, and con- 
verge on the dorsum of the organ to form the dorsal vein ; others pass out on the 
upper surface of the corpora cavernosa and join the dorsal vein; some emerge from 
the under surface of the corpora cavernosa, and, receiving branches from the corpus 
spongiosum, wind round the sides of the penis to terminate in the dorsal vein ; but 
the Greater number pass out at the root of the penis and join the prostatic plexus 
and pudendal veins (Fig. 646). 966 
MALE GENERATIVE ORGANS. 
The Corpus spongiosum encloses the urethra, and is situated in the groove on 
the under surface of the corpora cavernosa. It commences posteriorly in front of 
the deep perineal fascia, between the diverging crura of the corpora cavernosa, where 
Fig. 646. 
From the Peripheral Portion of the Corpus Cavernosum Penis, under a low magnifying power (copied from 
Langer): 1, a, capillary network; b, cavernous spaces; 2, connection of the arterial twigs (a) with the cav- 
ernous spaces. 
it forms a rounded enlargement, the bulb, and terminates anteriorly in another 
expansion, the glans penis, which overlaps the anterior rounded extremity of the 
corpora cavernosa. The central portion or body of the corpus spongiosum is cylin- 
drical and tapers slightly from behind forward. 
The bulb varies in size in different subjects; it receives a fibrous investment 
from the anterior layer of the deep perineal fascia, and is surrounded by the Accel- 
erator urinae muscle. The urethra enters the bulb nearer its upper than its lower 
surface, being surrounded by a layer of erectile tissue, a thin prolongation of which 
is continued backward round the membranous and prostatic portions of the canal 
to the neck of the bladder, lying between the two layers of muscular tissue. The 
portion of the bulb below the urethra presents a partial division into two lobes, 
being marked externally by a linear raph£, whilst internally there projects inward 
for a short distance a thin fibrous septum more distinct in early life. 
Structure.-The corpus spongiosum consists of a strong fibrous envelope enclos- 
ing a trabecular structure which contains in its meshes erectile tissue. The fibrous 
envelope is thinner, whiter in color, and more elastic than that of the corpus cav- 
ernosum. The trabeculse are delicate, uniform in size, and the meshes between 
them small, their long diameter for the most part corresponding with that of the 
penis. A thin layer of muscular fibres, continuous behind with those of the 
bladder, forms part of the outer coat of the corpus spongiosum, and a second 
layer of muscular tissue is found immediately beneath the mucous membrane of 
the urethra. 
The lymphatics of the penis consist of a superficial and deep set; the former are 
derived from a dense network on the skin of the glans and prepuce and from the 
mucous membrane of the urethra, and terminate in the inguinal glands; the latter 
emerge from the corpora cavernosa and corpus spongiosum, and, passing beneath 
the pubic arch, join the deep lymphatics of the pelvis. 
The nerves are derived from the pudic nerve and the hypogastric plexus. On 
the glans and bulb some filaments of the cutaneous nerves have Pacinian bodies 
connected with them, and, according to Krause, many of them terminate in a pecu- 
liar form of end-bulb. 
The Testes and their Coverings (Fig. 647). 
The testes are two small glandular organs which secrete the semen; they are 
situated in the scrotum, being suspended by the spermatic cords. At an early 
period of foetal life the testes are contained in the abdominal cavity behind the THE PENIS. 
967 
peritoneum. Before birth they descend to the inguinal canal, along which they 
pass with the spermatic cord, and, emerging at the external abdominal ring, they 
descend into the scrotum, becoming invested in their course by numerous coverings 
Fig. 647. 
Skin 
Dartos 
Ext. spermatic fascia 
Cremasteric fascia 
Parietal tunica vaginalis 
Infundibuliform fascia 
Visceral tunica vaginalis 
Tunica albuginea 
A lobule of the testicle 
A septum 
Mediastinum 
Spermatic vein 
Digital fossa 
Epididymis 
Vas deferens 
Spermatic artery 
Internal muscular i 
tunic of Kolliker J 
Artery to vas 
Transverse Section through the Left Side of the Scrotum and the Left Testicle, the sac of the tunica vaginalis 
represented in a distended condition 
derived from the serous, muscular, and fibrous layers of the abdominal parietes, as 
well as by the scrotum. The coverings of the testis are the 
Skin 
Dartos 
Scrotum. 
Intercolumnar or External spermatic fascia. 
Cremasteric fascia. 
Infundibuliform or Fascia propria (Internal spermatic fascia). 
Tunica vaginalis. 
The Scrotum is a cutaneous pouch which contains the testes and part of the 
spermatic cords. It is divided into two lateral halves by a median line or raphd 
which is continued forward to the under surface of the penis and backward along 
the middle line of the perineum to the anus. Of these two lateral portions, the left 
is longer than the right, and corresponds with the greater length of the spermatic 
cord on the left side. Its external aspect varies under different circumstances: 
thus, under the influence of warmth and in old and debilitated persons it becomes 
elongated and flaccid, but under the influence of cold and in the young and robust 
it is short, corrugated, and closely applied to the testes. 
The scrotum consists of two layers, the integument and the dartos. 
The integument is very thin, of a brownish color, and generally thrown into 
folds or rugae. It is provided with sebaceous follicles, the secretion of which has 
a peculiar odor, and is beset with thinly-scattered, crisp hairs, the roots of which 
are seen through the skin. 
The dartos is a thin layer of loose reddish tissue endowed with contractility; 
it forms the proper tunic of the scrotum, is continuous around the base of the 
scrotum with the superficial fascia of the groin, perineum, and inner side of the 
thighs, and sends inward a distinct septum, septum scroti, which divides it into two 
cavities for the two testes, the septum extending between the raphd and the under 
surface of the penis as far as its root. 968 
MALE GENERATIVE ORGANS. 
The dartos is closely united to the skin externally, but connected with the sub- 
jacent parts by delicate areolar tissue, upon which it glides with the greatest facil- 
ity. The dartos is very vascular, and consists of a loose areolar tissue containing 
unstriped muscular fibre, but no fat. Its contractility is slow and excited by cold 
and mechanical stimuli, but not by electricity. 
The intercolumnar fascia is a thin membrane derived from the margin of the 
pillars of the external abdominal ring during the descent of the testis in the foetus, 
which is prolonged downward around the surface of the cord and testis. It is sepa- 
rated from the dartos by loose areolar tissue, which allows of considerable movement 
of the latter upon it, but is intimately connected with the succeeding layers. 
The cremasteric fascia consists of scattered bundles of muscular fibres (Cre- 
master muscle) connected together into a continuous covering by intermediate areo- 
lar tissue. The muscular fibres are derived from the lower border of the internal 
oblique muscle during the descent of the testis (p. 994). 
The fascia propria is a thin membranous layer which loosely invests the sur- 
face of the cord. It is a continuation downward of the infundibuliform process of 
the fascia transversalis, and is also derived during the descent of the testis in 
the foetus. 
The tunica vaginalis is described with the proper covering of the testis. (A 
more detailed account of the other coverings of the testis will be found in the 
description of the Surgical Anatomy of Inguinal Hernia.) 
Vessels and Nerves.-The arteries supplying the coverings of the testis are 
-the superficial and deep external pudic from the femoral, the superficial perineal 
branch of the internal pudic, and the cremasteric branch from the epigastric. The 
veins follow the course of the corresponding arteries. The lymphatics terminate 
in the inguinal glands. The nerves are-the ilio-inguinal branch of the lumbar 
plexus, the two superficial perineal branches of the pudic nerve, the inferior 
pudendal branch of the small sciatic nerve, and the genital branch of the genito- 
crural nerve. 
The Spermatic Cord extends from the internal abdominal ring, where the 
structures of which it is composed converge, to the back part of the testicle. It 
is composed of arteries, veins, lymphatics, nerves, and the excretory duct of the 
testicle. These structures are connected together by areolar tissue, and invested 
by the fasciae brought down by the testicle in its descent. In the abdominal wall 
the cord passes obliquely along the inguinal canal, lying at first beneath the Inter- 
nal oblique and upon the fascia transversalis; but nearer the pubes it rests 
upon Poupart's ligament, having the aponeurosis of the External oblique in front 
of it and the conjoined tendon behind it. It then escapes at the external 
ring and descends nearly vertically into the scrotum. The left cord is rather 
longer than the right, consequently the left testis hangs somewhat lower than 
its fellow. 
The arteries of the cord are-the spermatic, from the aorta; the artery of the 
vas deferens, from the superior vesical; and the cremasteric, from the deep epigas- 
tric artery. 
The spermatic artery supplies the testicle. On approaching the gland it gives 
off some branches which supply the epididymis, and others which perforate the 
tunica albuginea behind and spread out on its inner surface, or pass through the 
fibrous septum in its interior to be distributed on the membranous septa between 
the lobes. 
The artery of the vas deferens is a long slender vessel which accompanies the 
vas deferens, ramifying upon the coats of that duct and anastomosing with the 
spermatic artery near the testis. 
The cremasteric branch from the epigastric supplies the Cremaster muscle and 
other coverings of the cord. 
The spermatic veins leave the back part of the testis, and, receiving branches 
from the epididymis, unite to form a plexus (pampiniform plexus) which forms 
the chief mass of the cord. They pass up in front of the vas deferens, and unite to THE TESTES. 
969 
form a single trunk, which terminates on the right side in the inferior vena cava, on 
the left side in the left renal vein. 
The lymphatics are of large size, accompany the blood-vessels, and terminate in 
the lumbar glands. 
The nerves are the spermatic plexus from the sympathetic. This plexus is 
derived from the renal and aortic plexuses, joined by filaments from the hypo- 
gastric plexus which accompany the artery of the vas deferens. 
Testes. 
The Testes are suspended in the scrotum by the spermatic cords. Each gland 
is of an oval form, compressed laterally and having an oblique position in the scro- 
tum ; the upper extremity being directed forward 
and a little outward; the lower, backward and a 
little inward ; the anterior convex border looks for- 
ward and downward; the posterior or straight bor- 
der, to which the cord is attached, backward and 
upward. 
The anterior and lateral surfaces, as well as both 
extremities of the organ, are convex, free, smooth, 
and invested by the tunica vaginalis. The posterior 
border, to which the cord is attached, receives only 
a partial investment from that membrane. Lying 
upon the outer edge of this border is a long, narrow, 
flattened body, named, from its relation to the testis, 
the epididymis (oldup.o', testis). It consists of a 
central portion, or body ; an upper enlarged extrem- 
ity, the globus major, or head ; and a lower pointed 
extremity, the tail, or globus minor. The globus 
major is intimately connected with the upper end 
of the testicle by means of its efferent ducts; and 
the globus minor is connected with its lower end by 
cellular tissue and a reflection of the tunica vaginalis. 
The outer surface and upper and lower ends of the 
epididymis are free and covered by serous mem- 
brane ; the body is also completely invested by it, excepting along its inner border, 
where it is connected to the back of the testis by a fold of the serous membrane. 
Attached to the upper end of the testis or to the epididymis are one or more small 
pedunculated bodies. One of them is pretty constantly found between the globus 
major of the epididymis and the testicle, and is believed to be the remains of the 
upper extremity of the Mullerian duct (p. 135). They are termed the hydatids of 
Morgagni. When the testicle is removed from the body the position of the vas 
deferens on the posterior and inner side of the epididymis marks the side to which 
rhe gland has belonged. 
Size and Weight.-The average dimensions of this gland are from one and a 
half to two inches in length, one inch in breadth, and an inch and a quarter in the 
antero-posterior diameter; and the weight varies from six to eight drachms, the left 
testicle being a little the larger. 
The testis is invested by three tunics-the tunica vaginalis, tunica albuginea, 
and tunica vasculosa. 
The Tunica Vaginalis is the serous covering of the testis. It is a pouch of 
serous membrane derived from the peritoneum during the descent of the testis in 
the foetus from the abdomen into the scrotum. After its descent that portion of 
the pouch which extends from the internal ring to near the upper part of the gland 
becomes obliterated, the lower portion remaining as a shut sac which invests the 
outer surface of the testis, and is reflected on to the internal surface of the scrotum: 
hence it may be described as consisting of a visceral and parietal portion. 
Fig. 648. 
Spermatic 
- rtery 
cf Cord 
Tunica Vaginalis 
parittal layer- \ 
Head 
Te s t is 
The 970 
MALE GENERATIVE ORGANS. 
The visceral portion (tunica vaginalis propria} covers the outer surface of the 
testis as well as the epididymis, connecting the latter to the testis by means of a 
distinct fold. From the posterior border of the gland it is reflected on to the inter- 
nal surface of the scrotum. 
The parietal portion of the serous membrane (tunica vaginalis reflexa) is far more 
extensive than the visceral portion, extending upward for some distance in front and 
on the inner side of the cord and reaching below the testis. The inner surface of 
the tunica vaginalis is free, smooth, and covered by a simple epithelial layer of flat- 
tened cells. The interval between the visceral and parietal layers of this membrane 
constitutes the cavity of the tunica vaginalis. 
The obliterated portion of the pouch may generally be seen as a fibro-cellular 
thread lying in the loose areolar tissue around the spermatic cord; sometimes this 
may be traced as a distinct band from the upper end of the inguinal canal, where it 
is connected with the peritoneum, down to the tunica vaginalis ; sometimes it gradu- 
ally becomes lost on the spermatic cord. Occasionally no trace of it can be detected. 
In some cases it happens that the pouch of peritoneum does not become obliterated, 
but the sac of the peritoneum communicates with the tunica vaginalis. This may 
give rise to one of the varieties of inguinal hernia (p. 998). Or in other cases the 
pouch may contract, but not become entirely obliterated; it then forms a minute 
canal leading from the peritoneum to the tunica vaginalis.1 
The Tunica Albuginea is the fibrous covering of the testis. It is a dense 
fibrous membrane, of a bluish-white color, composed of bundles of white fibrous 
tissue, which interlace in every direction. Its outer surface is covered by the tunica 
vaginalis, except along its posterior border, at the points of attachment of the epi- 
didymis ; hence the tunica albuginea is usually considered as a fibro-serous mem- 
brane, like the pericardium. This membrane surrounds the glandular structure of 
the testicle, and at its posterior border is reflected into the interior of the gland, 
forming an incomplete vertical septum called the mediastinum testis (corpus 
Highmorianum). 
The mediastinum testis extends from the upper nearly to the lower border of 
the gland, and is wider above than below. From the front and sides of this septum 
numerous slender fibrous cords and imperfect septa (trabeculce) are given off, which 
radiate toward the surface of the organ and are attached to the inner surface of the 
tunica albuginea. They therefore divide the interior of the organ into a number 
of incomplete spaces, which are somewhat cone-shaped, being broad at their bases 
at the surface of the gland and becoming narrower as they converge to the medias- 
tinum. The mediastinum supports the vessels and ducts of the testis in their pas- 
sage to and from the substance of the gland. 
The Tunica Vasculosa (pria mater testis) is the vascular layer of the testis, con- 
sisting of a plexus of blood-vessels held together by a delicate areolar tissue. It 
covers the inner surface of the tunica albuginea and the different septa in the inte- 
rior of the gland, and therefore forms an internal investment to all the spaces of 
which the gland is composed. 
Structure.-The glandular structure of the testis consists of numerous lobules 
(lobuli testis). Their number in a single testis is estimated by Berres at 250, and 
by Krause at 400. They differ in size according to their position, those in the 
middle of the gland being larger and longer. The lobules are conical in shape, the 
base being directed toward tbe circumference of the organ, the apex toward the 
mediastinum. Each lobule is contained in one of the intervals between the fibrous 
cords and vascular processes which extend between the mediastinum testis and the 
tunica albuginea, and consists of from one to three or more minute convoluted tubes, 
the tubuli seminiferi. The tubes may be separately unravelled by careful dissection 
under water, and may be seen to commence either by free caecal ends or by anasto- 
1 It is recorded that in the post-mortem examination of Sir Astley Cooper this minute canal was 
found on both sides of the body. Sir Astley Cooper states that when a student he suffered from 
inguinal hernia; probably this was of the congenital variety, and the canal found after death was 
rhe remains of the one down which the hernia travelled (Lancet, vol. ii., 1824, p. 116). THE TESTES. 
971 
motic loops. The total number of tubes is considered by Munro to be about 300, 
and the length of each about 16 feet; by Lauth their number is estimated at 840, 
and their average length 2| feet. Their diameter varies from to of an 
inch. The tubuli are pale in color in early life, but in old age they acquire a deep 
yellow tinge from containing much fatty matter. They consist of a membrana pro- 
pria, inside which are several layers of epithelial cells, the seminal cells. The mem- 
brana propria is a hyaline structure, consisting of several membranous layers con- 
taining oval flattened nuclei at regular intervals superimposed on one another. The 
seminal cells or lining epithelium differs in different tubules. In some tubes they 
may be seen to consist of an outer layer next the membrana propria, and two or 
more layers of inner cells. The former cells are more or less polyhedral in shape, 
uniform in size, and contain an oval or spherical nucleus; the latter cells, those 
comprising the inner layers, are spherical and more loosely connected together. The 
nucleus of most or all of them is in the process of indirect division (Jcaryokinesis, 
p. 42), and in consequence of this numerous small spherical daughter-cells are to 
be seen, lying nearest to the lumen and closely connected together. These small 
daughter-cells are named spermatoblasts, and by a series of changes become con- 
verted into spermatozoa. In other tubes the gradual transition of the spermato- 
blasts into spermatozoa may be traced. In some tubes or parts of tubes the daughter- 
cells may be seen to have assumed a pear shape, with the pointed end, in which the 
nucleus is to be found, directed toward the inner seminal cells, while the broad part 
is directed into the lumen of the tube. In other parts of a tube the broad end may 
be seen to have become elongated into a rod-shaped body, which constitutes the 
middle piece of the spermatozoa, while the nucleus forms the head. Again, in other 
parts of the tubes these young spermatozoa may be seen collected togethei' into fan- 
shaped groups, and from their distal end-that is to say, the end projecting into the 
lumen of the tube-a thin long filament, called the tail, is growing out. In the 
young subject the seminal cells present somewhat the appearance of an epithelial 
lining, and do not almost fill the tube, as in the adult testis. 
The tubules are enclosed in a delicate plexus of capillary vessels, and are held 
together by an intertubular connective tissue which presents large interstitial spaces 
lined by endothelium, which are believed to be the rootlets of the lymphatic vessels 
of the testis. 
In the apices of the lobules the tubuli become less convoluted, assume a nearly 
straight course, and unite together to form from twenty to thirty large ducts, of 
about of an inch in diameter, and these, from their straight course, are called 
vasa recta. 
The vasa recta enter the fibrous tissue of the mediastinum, and pass upward and 
backward, forming, in their ascent, a close network of anastomosing tubes which are 
merely channels in the fibrous stroma, having no proper walls; this constitutes the 
rete testis. At the upper end of the mediastinum the vessels of the rete testis ter- 
minate in from twelve to fifteen or twenty ducts, the vasa efferentia: they perforate 
the tunica albuginea and carry the seminal fluid from the testis to the epididymis. 
Their course is at first straight; they then become enlarged and exceedingly convo- 
luted, and form a series of conical masses, the coni vasculosi, which together consti- 
tute the globus major of the epididymis. Each cone consists of a single convoluted 
duct from six to eight inches in length, the diameter of which gradually decreases 
from the testis to the epididymis. Opposite the bases of the cones the efferent ves- 
sels open at narrow intervals into a single duct, which constitutes by its complex 
convolutions the body and globus minor of the epididymis. When the convolutions 
of this tube are unravelled it measures upward of twenty feet in length, and increases 
in breadth and thickness as it approaches the vas deferens. The convolutions are 
held together by fine areolar tissue and by bands of fibrous tissue. A long narrow 
tube, the vas aberrans of Haller, is occasionally found connected with the lower part 
of the canal of the epididymis or with the commencement of the vas deferens. It 
extends up into the cord for about two or three inches, where it terminates by a blind 
extremity, which is occasionally bifurcated. Its length varies from an inch and a 972 
MALE GENERATIVE ORGANS. 
half to fourteen inches, and sometimes it becomes dilated toward its extremity: 
more commonly it retains the same diameter throughout. Its structure is similar 
to that of the vas deferens. Occasionally it is found 
unconnected with the epididymis. 
The vasa recta are of smaller diameter than the 
seminal tubes, and have very thin parietes. They 
as well as the channels of the rete testis are lined by 
a single layer of flattened epithelium. The vasa 
efferentia and the tube of the epididymis have walls 
of considerable thickness, on account of the presence 
in them of muscular tissue, which is principally 
arranged in a circular manner. These tubes are 
lined by columnar ciliated epithelium. 
The Vas Deferens [Figs. 639, p. 956, 649, and 
682, p. 1022], the excretory duct of the testis, is the 
continuation of the epididymis. Commencing at the 
lower part of the globus minor, it ascends along the 
posterior and inner side of the testis and epididymis, 
and along the back part of the spermatic cord, through 
the spermatic canal, to the internal abdominal ring. 
From the ring it descends into the pelvis, crossing the 
external iliac vessels, and curves round the outer side 
of the deep epigastric artery : at the side of the blad- 
der it arches backward and downward to its base, 
crossing over the obliterated hypogastric artery and 
to the inner side of the ureter. At the base of the 
bladder it lies between that viscus and the rectum, run- 
ning along the inner border of the vesicula seminalis. In this situation it becomes 
enlarged and sacculated, and then, becoming narrowed at the base of the prostate, 
unites with the duct of the vesicula seminalis to form the ejaculatory duct. The 
vas deferens presents a hard and cord-like sensation to the fingers; it is about two 
feet in length, of cylindrical form, and about a line and a quarter in diameter. Its 
walls are dense, measuring one-third of a line, and its canal is extremely small, 
measuring about half a line. 
Structure.-The vas deferens consists of three coats: 1, an external or cellular 
coat; 2, a muscular coat, which in the greater part of the tube consists of two 
layers of unstriped muscular fibre-an outer, longitudinal in direction, and an 
inner, circular; but in addition to these at the commencement of the vas deferens 
there is a third layer, consisting of longitudinal fibres placed internal to the circular 
stratum, between it and the mucous membrane; 3, an internal or mucous coat, 
which is pale and arranged in longitudinal folds; its epithelial covering is of the 
columnar variety. 
Fig. 649. 
Tunica Vaginalis 
Tunica AUugin ea 
its Selltec 
Vertical Section of the Testicle, to show 
the Arrangement of the Ducts. 
VESICULJE SEMINALES. 
The Seminal Vesicles are two lobulated membranous pouches placed between 
the base of the bladder and the rectum, serving as reservoirs for the semen, and 
secreting a fluid to be added to the secretion of the testicles. Each sac is somewhat 
pyramidal in form, the broad end being directed backward and the narrow end for- 
ward toward the prostate. They measure about two and a half inches in length, 
about five lines in breadth, and two or three lines in thickness. They vary, how- 
ever, in size, not only in different individuals, but also in the same individual on 
the two sides. Their zipper surface is in contact with the base of the bladder, 
extending from near the termination of the ureters to the base of the prostate 
gland. Their under surface rests upon the rectum, from which they are separated 
by the recto-vesical fascia. Their posterior extremities diverge from each other. 
Their anterior extremities are pointed, and converge toward the base of the pros- VEST CELLE SEMINALES. 
973 
tate gland, where each joins with the corresponding vas deferens to form the ejac- 
ulatory duct. Along the inner margin of each vesicula runs the enlarged and con- 
voluted vas deferens. The inner border of the vesiculae and the corresponding vas 
deferens form the lateral boundary of a triangular space limited behind by the recto- 
vesical peritoneal fold; the portion of the bladder included in this space rests on 
the rectum and corresponds with the trigonum vesicae in its interior. [If the finger 
in the rectum reach beyond the prostate, the vesiculae seminales and the trigonum 
may be defined by touch.] 
Each vesicula consists of a single tube coiled upon itself and giving off several 
irregular caecal diverticula, the separate coils, as well as the diverticula, being con- 
nected together by fibrous tissue. When 
uncoiled this tube is about the diameter of 
a quill, and varies in length from four to 
six inches; it terminates posteriorly in a cul- 
de-sac ; its anterior extremity becomes con- 
stricted into a narrow straight duct, which 
joins on its inner side with the correspond- 
ing vas deferens and forms the ejaculatory 
duct. 
The Ejaculatory Ducts, two in number, 
one on each side, are formed by the junction 
of the duct of the vesicula seminalis with the 
vas deferens. Each duct is about three-quar- 
ters of an inch in length ; it commences at 
the base of the prostate, and runs forward 
and upward in a canal in its substance and 
along the side of the sinus pocularis to ter- 
minate by a separate slit-like orifice close to 
or just within the margins of the sinus. The 
ducts diminish in size and converge toward 
their termination. 
Structure.-The vesiculae seminales are 
composed of three coats: an external or 
iibro-cellular, derived from the recto-vesical 
fascia; a middle or muscular coat, which is thinner than in the vas deferens: the 
muscular fibres are arranged in three layers, consisting of an inner and outer longi- 
tudinal stratum and an intermediate layer of circular fibres; and an internal or 
mucous coat, which is pale, of a whitish-brown color, and presents a delicate reticular 
structure, like that seen in the gall-bladder, but the meshes are finer. The epithe- 
lium is columnar. 
The coats of the ejaculatory ducts are extremely thin ; an outer fibrous layer, 
which is almost entirely lost after their entrance into the prostate; a layer of mus- 
cular fibres, consisting of an outer thin circular and an inner longitudinal layer; and 
the mucous membrane, forming the only constituents of the tubes. 
Vessels and Nerves.-The arteries supplying the vesiculae seminales are de- 
rived from the inferior vesical and middle hemorrhoidal. The veins and lymphatics 
accompany the arteries. The nerves are derived fiom the pelvic plexus. 
The Semen is a thick, whitish fluid having a peculiar odor. It consists of a 
fluid, the liquor seminis, and solid particles, the seminal granules and spermatozoa. 
The liquor seminis is transparent, colorless, and of an albuminous composition, 
containing particles of squamous and columnar epithelium, with oil-globules and 
granular matter floating in it, besides the above-mentioned, solid elements. 
The seminal granules are round, finely-granular coipuscles, measuung 4wVtrth of 
an inch in diameter. 
The spermatozoa, or spermatic filaments, are the essential agents m producing 
fecundation. They consist of a flattened oval head (the nucleus of the original sper- 
matoblast), of a rod-shaped middle piece, and [of] a long slender caudal filament or 
Frc. 650. 
Right Ejaculatory 
ducc 
Base of the Bladder, with the Vasa Deferentia 
and Vesiculee Seminales. 974 
MALE GENERATIVE ORGANS. 
tail. The movements of these bodies are remarkable, and consist of a lashing or 
undulatory motion of the tail. 
DESCENT OF THE TESTES. 
The testes at an early period of foetal life are placed at the back part of the 
abdominal cavity, behind the peritoneum, in. front and a little below the kidneys. 
The anterior surface and sides are invested by peritoneum; the blood-vessels and 
efferent ducts are connected with their posterior surface; and attached to the lower 
end is a peculiar structure, the gubernaculum testis, which is said to assist in their 
descent. 
The Gubernaculum Testis [was first described and named by John Hunter. 
It appears at the third month of intra-uterine life, and] attains its full development 
between the fifth and sixth months: it is a conical-shaped cord attached above to 
the lower end of the epididymis and below to the bottom of the scrotum. [Mr. C. 
B. Lockwood1 states that at the sixth to the eighth month of intra-uterine life many 
of the lower fibres extend into Scarpa's triangle, the perineum, etc., and may thus 
explain the occasional presence of the testicle in these regions.] It is placed behind 
the peritoneum, lying upon the front of the Psoas muscle and completely filling the 
inguinal canal. It consists of a soft, transparent areolar tissue within, which often 
[Fig. 652. 
[Fig. 651. 
[Fig. 653. 
Diagrams to Illustrate the Descent of the Testis and the Formation of the Tunica Vaginalis 
(drawn by J. T. Gray)-(Heath).] 
appears partially hollow, surrounded by a layer of striped muscular fibres, which 
ascends upon this body to be attached to the testis. According to Mr. Curling, the 
gubernaculum as well as these muscular fibres divides below into three processes: the 
P This important paper is published in outline in the Brit. Med. Joum., March 5, 12, and 19,1887.] DESCENT OF THE TESTES. 
975 
external and broadest process is connected with Poupart's ligament in the inguinal 
canal; the middle process descends along the inguinal canal to the bottom of the 
scrotum, where it joins the dartos; the internal one is firmly attached to the os 
pubis ' and sheath of the Rectus muscle; some fibres, moreover, are reflected from 
the Internal oblique on to the front of the gubernaculum. Up to the fifth month 
the testis is situated in the lumbar region, covered in front and at the sides by 
peritoneum, and supported in its position by a fold of that membrane, called the 
mesorchium; between the fifth and sixth months the testis descends to the iliac 
fossa, the gubernaculum at the same time becoming shortened; during the seventh 
month it enters the internal abdominal ring, a small pouch of peritoneum (processus 
vaginalis) preceding the testis in its course through the canal [which explains how a 
hydrocele may exist with an undescended testicle (Allis)]. By the end of the eighth 
month the testis has descended into the scrotum, carrying down with it a lengthened 
pouch of peritoneum, which communicates by its upper extremity with the peritoneal 
cavity. Just before birth the upper part of the pouch usually becomes closed, and 
this obliteration extends gradually downward to within a short distance of the testis. 
The process of peritoneum surrounding the testis, which is now entirely cut off from 
the peritoneal cavity, constitutes the tunica vaginalis.1 
Mr. Curling believes that the descent of the testis is effected by means of the 
muscular fibres of the gubernaculum; those fibres which proceed from Poupart's 
ligament and the Obliquus internus are said to guide the organ into the inguinal 
canal; those attached to the pubes draw it below the external abdominal ring; and 
those attached to the bottom of the scrotum complete its descent.2 During the 
descent of the organ these muscular fibres become gradually everted, forming a 
muscular layer which becomes placed external to the process of the peritoneum, 
surrounding the gland and spermatic cord, and constitutes the Cremaster. In the 
female a small cord, corresponding to the gubernaculum in the male, descends to 
the inguinal region, and ultimately forms the round ligament of the uterus. A 
pouch of peritoneum accompanies it along the inguinal canal, analogous to the pro- 
cessus vaginalis in the male: it is called the canal of Nuck. 
[The Cremaster is wrongly described as the lower fibres of the Internal oblique, 
on which the testicle catches in its descent, and pulls them down. As a matter of 
fact, some of these looping fibres of the Cremaster extend upward along the guber- 
naculum while the testis is in the abdomen, and long before the testis reaches the 
inguinal canal other muscular fibres of the abdominal wall may be seen looping 
downward toward the scrotum.] 
1 The obliteration of the process of peritoneum which accompanies the cord, and is hence called 
the funicular process, is often incomplete. (For an account of the various conditions produced by 
such incomplete obliteration, which are of great importance in the pathological anatomy of inguinal 
hernia, the student is referred to the " Essay on Hernia," by Mr. Birkett, in A System of Surgery, 
edited by T. Holmes, vol. iv.) 
2 Cleland denies that the gubernaculum is the agent by which the change in the position of the 
testis is effected. (For an interesting resume of the various views which have been held with regard 
to the descent of the testis, see MecAcim'sm of the Gubernaculum Testis, by Cleland, Edinburgh, 1856.) Female Organs of Generation. 
IP TIE external Organs of Generation in the female are the mons Veneris, the 
I labia majora and minora, the clitoris, the meatus urinarius, and the orifice of 
the vagina. The term "vulva" or "pudendum," as generally applied, includes all 
these parts. 
The mons Veneris is the rounded eminence in front of the pubes formed by a 
collection of fatty tissue beneath the integument. It surmounts the vulva and 
becomes covered with hair at the time of puberty. 
The Labia majora ['] are two prominent longitudinal cutaneous folds extending 
downward from the mons Veneris to the 
anterior boundary of the perineum, and 
enclosing an elliptical fissure, the common 
urino-sexual opening. Each labium is 
formed externally of integument covered 
with hair; internally, of mucous mem- 
brane, which is continuous with the genito- 
urinary mucous tract; and, between the 
two, of a considerable quantity of areolar 
tissue, fat, and a tissue resembling the 
dartos of the scrotum, besides vessels, 
nerves, and glands. The labia are thicker 
in front than behind, and joined together 
at each extremity, forming the anterior and 
posterior commissures. The interval left 
between the posterior commissure and the 
margin of the anus is about an inch in 
length, and constitutes the perineum. Just 
within the posterior commissure is a small 
transverse fold, the frcenulum pudendi or 
fourchette, which is commonly ruptured in 
the first parturition, and the space between 
it and the commissure is called the fossa 
navicularis. The labia are analogous to 
the scrotum in the male. 
The Labia minora [*] orNymphse are 
two small folds of mucous membrane sit- 
uated within the labia majora, extending 
from the clitoris obliquely downward and 
outward for about an inch and a half on 
each side of the orifice of the vagina, on 
the sides of which they are lost. They 
are continuous externally with the labia 
majora, internally with the inner surface 
of the vagina. As they converge toward 
the clitoris in front each labium divides 
into two folds, which surround the glans clitoridis, the superior folds uniting to form 
the praeputium clitoridis, the inferior folds being attached to the glans and forming 
the fraenum. The nymphae are composed of mucous membrane, covered by a thin 
epithelial layer. They contain a plexus of vessels in their interior, and are pro- 
Fig. 654. 
zfioirrrA e. ffc. 
~jFossct Jia atcu - 
laris 
Rsl. com 
7nisszzr& 
The Vulva, external Female Organs of Generation. 
976 
P In the singular number "labium majus" and "minus."] FEMALE ORGANS OF GENERATION. 
977 
vided with numerous large mucous crypts which secrete abundance of sebaceous 
matter. 
The Clitoris is an erectile structure analogous to the corpora cavernosa of the 
penis. [It differs from the penis in having no corpus spongiosum and no urethra.] 
It is situated beneath the anterior commissure, partially hidden between the ante- 
rior extremities of the labia minora. It is an elongated organ, connected to the 
rami of the pubes and ischia on each side by a crus; the body is short and con- 
cealed beneath the labia; the free extremity, or glans clitoridis, is a small rounded 
tubercle consisting of spongy erectile tissue and highly sensitive. The clitoris con- 
sists of two corpora cavernosa, composed of erectile tissue enclosed in a dense layer 
of fibrous membrane, united together along their inner surfaces by an incomplete 
fibrous pectiniform septum. It is provided, like the penis, with a suspensory liga- 
Fig. 655. 
Section of 
Peritoneum 
\ 
Section of Female Pelvis, showing position of viscera.1 [Compare the better figure, Fig. 656, p. 978.] 
ment and with two small muscles, the Erectores clitoridis, which are inserted into 
the crura of the corpora cavernosa. 
Between the clitoris and the entrance of the vagina is a triangular smooth sur- 
face bounded on each side by the nymphse; this is the vestibule. 
The orifice of the urethra"(meatus urinarius) is situated at the back part of 
the vestibule, about an inch below the clitoris and near the margin of the vagina, 
surrounded by a prominent elevation of the mucous membrane. Below the meatus 
urinarius is the orifice of the vagina, an elliptical apeituie, moie oi less closed m 
the virgin by a membranous fold, the hymen. 
The Hymen is a thin semilunar fold of mucous membrane stretched across the 
1 The student must bear in mind, that, though in this diagram the vagina is represented as a 
widely-open tube or canal for the sake of clearness, it is not so in its normal condition, but that, as 
stated in the text, its walls are ordinarily in contact with each other. The same remark applies to 
the urethra in Fig. 639, p. 956. 978 
FEMALE ORGANS OF GENERATION. 
lower part of the orifice of the vagina, its concave margin being turned upward 
toward the pubes. Sometimes 
this membrane forms a complete 
septum across the orifice of the 
vagina-a condition known as 
imperforate hymen. Occasion- 
ally it forms a circular septum, 
perforated in the centre by a 
round opening ; sometimes it is 
cribriform, or its free margin 
forms a membranous fringe, or it 
may be entirely absent. It may 
also persist after copulation. The 
hymen cannot, consequently, be 
considered as a test of virginity. 
Its rupture or the rudimentary 
condition of the membrane above 
referred to gives rise to those 
small rounded elevations which 
surround the opening of the va- 
gina, the carunculoe myrtiformes. 
G-lands of Bartholine.-On 
each side of the commencement 
of the vagina is a round or ob- 
long body, of a reddish-yellow 
color and of the size of a horse- 
bean, analogous to Cowper's 
gland in the male. It is called 
the gland of Bartholine. Each 
gland opens by means of a long 
single duct upon the inner side of the nymphae, external to the hymen. [Occasion- 
ally these become inflamed or obstructed and cause retention-cysts or abscesses.] 
Extending from the clitoris, along either side of the vestibule and lying a little 
behind the nymphae, are two large oblong masses, about an inch in length, consist- 
ing of a plexus of veins enclosed in a thin layer of fibrous membrane. These 
bodies are narrow in front, rounded below, and are connected with the crura of the 
clitoris and rami of the pubes: they are termed by Kobelt the bulbi vestibuli, and 
he considers them analogous to the bulb of the corpus spongiosum in the male. 
Immediately in front of these bodies is a smaller venous plexus continuous with the 
bulbi vestibuli behind and the glans clitoridis in front; it is called by Kobelt the 
pars intermedia, and is considered by him as analogous to that part of the body 
of the corpus spongiosum which immediately succeeds the bulb. 
[For the anatomy of the perineum in the female, see p. 1015.] 
[Fig. 656. 
Antero-posterior (sagittal) Section of the Pelvic Organs of a Vir- 
gin : 1, vagina; 2, uterus; 3, posterior lip: 4, anterior lip; 5, 
anus; 6, perineum; 7, symphysis pubis; 8, fimbriated extremity 
of the Fallopian tube; 9, the empty bladder-note its Y shape, 
and also that the walls of the uterus, vagina, urethra, and blad- 
der are in contact except when distended by their appropriate 
contents (D. Berry Hart).] 
The Bladder. 
The Bladder [Figs. 656 and 657] is situated at the anterior part of the pelvis. 
It is in relation in front with the pubic bones; behind with the uterus, some convo- 
lutions of the small intestine being interposed; its base lies in contact with the neck 
of the uterus and with the anterior wall of the vagina. The bladder is said to be 
larger in the female than in the male (though this is denied by Henle), and is very 
broad in its transverse diameter. [Observe its Y shape when empty, and that when 
distended it would rise above the pubes, and the peritoneum also be lifted up above 
the pubes, as in Fig. 655.] 
The Urethra. 
The Urethra is a narrow membranous canal, about an inch and a half in length, THE VAGINA. 
979 
extending from the neck of the bladder to the meatus urinarius. It is placed beneath 
the symphysis pubis, imbedded in the anterior wall of the vagina, and its direction 
is obliquely downward and forward, its course being slightly curved, the concavity 
directed forward and upward. Its diameter when undilated is about a quarter of an 
inch. The urethra perforates the triangular ligament precisely as in the male, and 
is surrounded by the muscular fibres of the Compressor urethrae. 
Structure.-The urethra consists of three coats : muscular, erectile, and mucous. 
The muscular coat is continuous with that of the bladder; it extends the whole 
length of the tube and consists of a circular stratum of muscular fibres. In addi- 
tion to this, between the two layers of the triangular ligament the female urethra is 
surrounded by the Constrictor urethrae, as in the male. 
A thin layer of spongy erectile tissue, containing a plexus of large veins inter- 
mixed with bundles of unstriped muscular fibre, lies immediately beneath the 
mucous coat. 
The mucous coat is pale, continuous externally with that of the vulva, and inter- 
nally with that of the bladder. It is thrown into longitudinal folds, one of which, 
placed along the floor of the canal, resembles the verumontanum in the male urethra. 
It is lined by laminated epithelium, which becomes transitional near the bladder. Its 
external orifice is surrounded by a few mucous follicles. 
The urethra, from not being surrounded by dense resisting structures, as in the 
male, admits of considerable dilatation, which enables the surgeon to remove with 
considerable facility calculi or other foreign bodies from the cavity of the bladder. 
The Rectum is more capacious and less curved in the female than in the male. 
The first portion extends from the left sacro-iliac symphysis to the middle of the 
sacrum. Its connections are similar to those in the male. 
The second portion extends to the tip of the coccyx. It is covered in front by 
the peritoneum for a short distance at its upper part: it is in relation with the pos- 
terior wall of the vagina. 
The third portion curves backward from the vagina to the anus, leaving a space 
which corresponds on the surface of the body to the perineum. Its extremity is sur- 
rounded by the Sphincter muscles, and its sides are supported by the Levatores ani. 
The Rectum. 
The Vagina. 
The Vagina [Fig. 656] is a membranous canal extending from the vulva to the ute- 
rus. It is situated in the cavity of the pelvis, behind the bladder and in front of the 
rectum. Its direction is curved forward and downward, following at first the line of 
the axis of the cavity of the pelvis, and afterward that of the outlet. It is cylindrical 
in shape, flattened from before backward, and its walls are ordinarily in contact with 
each other. ? Its length is about four inches along its anterior wall, and between five 
and six inches along its posterior wall. It is constricted at its commencement, and 
becomes dilated near its uterine extremity; it surrounds the vaginal portion of the 
cervix uteri a short distance from the os, its attachment extending higher up on the 
posterior than on the anterior wall of the uterus. 
Relations.-Its anterior surface is in relation with the base of the bladder 
and with the urethra. Its posterior surface is connected to the anterior wall of the 
rectum for the lower three-fourths of its extent, the upper fourth being separated 
from that tube by the recto-uterine fold of peritoneum, which forms a cul-de-sac 
between the vagina and rectum. Its sides give attachment superiorly to the broad 
ligaments and inferiorly to the Levatores arii muscles and recto-vesical fascia. 
Structure.-The vagina consists of an internal mucous lining, of a muscular 
coat, and of an external layer of erectile tissue. 
The mucous membrane is continuous above with that lining the uterus, and 
below with the integument covering the labia majora. Its inner surface presents 980 
FEMALE ORGANS OF GENERATION. 
along the anterior and posterior walls a longitudinal ridge or raphd called the col- 
umns of the vagina, and numerous transverse ridges or rugae extending outward 
from the raphe on either side. These rugae are divided by furrows of variable 
depth, giving to the mucous membrane the appearance of being studded over with 
conical projections or papillae; they are most numerous near the orifice of the vagina, 
especially before parturition. The epithelium covering the mucous membrane is of 
the squamous variety. The submucous tissue is very loose, and contains numerous 
[Fig. 657. 
Transverse Section of the Body, showing relations of fundus uteri: m, pubes; a, a, hypogastric arteries in 
front of the bladder, spermatic vessels and nerves behind the ovaries; b, bladder; l, l, round ligaments; 
u, fundus uteri; t, t, Fallopian tubes: f, fimbriated extremity of Fallopian tubes: b, broad ligament of 
uterus; o, o, ovaries; r, rectum; g, right ureter; c, utero-sacral ligaments; v, last lumbar vertebra (Savage).] 
large veins, which by their anastomoses form a plexus, together with smooth mus- 
cular fibres derived from the muscular coat; it is regarded by Gussenbauer as an 
erectile tissue. 
The muscular coat consists of two layers-an external longitudinal, which is far 
the stronger, and an internal circular layer. The longitudinal fibres are continuous 
with the superficial muscular fibres of the uterus. The strongest fasciculi are those 
attached to the recto-vesical fascia on each side. The two layers are not distinctly 
separable from each other, but are connected by oblique decussating fasciculi which 
pass from the one layer to the other. In addition to this, the vagina at its lower 
end is surrounded by a band of striped muscular fibres, the sphincter vagince. (See 
p. 1015.) 
The erectile tissue consists of a layer of loose connective tissue situated between 
the mucous membrane and the muscular coat; imbedded in it is a plexus of large 
veins and numerous bundles of unstriped muscular fibres derived from the circular 
muscular layer. The arrangement of the veins is similar to that found in other 
erectile tissues. 
The Uterus. 
The Uterus [Figs. 656 and 657] is the organ of gestation, receiving the fecun- 
dated ovum in its cavity, retaining and supporting it during the development of the 
foetus, and becoming the principal agent in its expulsion at the time of parturition. 
In the virgin state it is pear-shaped, flattened from before backward, and situ- 
ated in the cavity of the pelvis between the bladder and the rectum; it is retained 
in its position by the round and broad ligaments on each side, and projects into the 
upper end of the vagina below. Its upper end, or base, is directed upward and for- 
ward ; its lower end, or apex, downward and backward in the line of the axis of 
the inlet of the pelvis. It therefore forms an angle with the vagina, since the 
direction of the vagina corresponds to the axis of the cavity and outlet of the THE UTERUS. 
981 
pelvis. The uterus measures about three inches in length, two in breadth at its 
upper part, and an inch in thickness, and it weighs from an ounce to an ounce 
and a half. 
The fundus is the upper broad extremity of the organ: it is convex, covered by 
peritoneum, and placed on a line below the level of the brim of the pelvis. 
The body gradually narrows from the fundus to the neck. Its anterior surface 
is flattened, covered by peritoneum in the upper three-fourths of its extent, and 
separated from the bladder by some convolutions of the small intestine: the lower 
fourth is connected to the bladder. Its posterior surface is convex, covered by 
peritoneum throughout, and separated from the rectum by some convolutions of the 
intestine. Its lateral margins are concave and give attachment to' the Fallopian 
tube above, the round ligament below and in front of this, and the ligament of the 
ovary behind and between both of these structures. 
The cervix is the lower rounded and constricted portion of the uterus: around 
its circumference is attached the upper end of the vagina, which extends upward a 
greater distance behind than in front. 
At the vaginal extremity of the uterus is a transverse aperture, the os uteri, 
bounded by two lips, the anterior of which is thick, the posterior narrow and long. 
Ligaments.-The ligaments of the uterus are eight in number: two anterior, 
two posterior, and two lateral formed of peritoneum, and the round ligaments 
(p. 988). 
The two anterior ligaments (vesico-uterine) are two semilunar folds which pass 
between the neck of the uterus and the posterior surface of the bladder. 
The two posterior ligaments (recto-uterine) pass between the sides of the uterus 
and rectum. The fold of peritoneum which forms these ligaments is reflected from 
the anterior surface of the second portion of the rectum on to the posterior surface 
of the upper part of the vagina, and thence passes up on to the posterior wall of 
the uterus. It thus forms a pouch or cul-de-sac which is termed the recto-vaginal 
pouch or pouch of Douglas. 
The tivo lateral or broad ligaments pass from the sides of the uterus to the lateral 
walls of the pelvis, forming a septum across the pelvis which divides that cavity into 
two portions. In the anterior part are contained the bladder, urethra, and vagina; 
in the posterior part, the rectum. 
The cavity of the uterus is small in comparison with the size of the organ: that 
portion of the cavity which corresponds to the body is triangular, having its base 
directed upward toward the fundus, and is flattened from before backward, so that 
its walls are closely approximated. At each superior angle is a funnel-shaped cavity 
which constitutes the remains of the division of the body of the uterus into two cor- 
nua, and at the bottom of each cavity is the minute orifice of the Fallopian tube. 
At the inferior angle of the uterine cavity is a small constricted opening, the inter- 
nal orifice (ostium internum), which leads into the cavity of the cervix. The cavity 
of the cervix is somewhat fusiform, flattened from before backward, broader at the 
middle than at either extremity, and communicates below with the vagina. Each 
wall of the canal presents a longitudinal column, from which proceed a number of 
small oblique columns, giving the appearance of branches from the stem of a tree, 
and hence the name arbor vitae uterina applied to it. These folds usually become 
very indistinct after the first labor. 
Structure.-The uterus is composed of three coats-an external serous coat, a 
middle or muscular layer, and an internal mucous coat. 
The serous coat is derived from the peritoneum; it invests the fundus and the 
whole of the posterior surface of the body of the uterus, but only the upper three- 
fourths of its anterior surface. 
The muscular coat forms the chief bulk of the substance of the uterus. In the 
unimpregnated state it is dense, firm, of a grayish color, and cuts almost like 
cartilage. It is thick opposite the middle of the body and fundus, and thin at 
the orifices of the Fallopian tubes. It consists of bundles of unstriped muscular 
fibres, disposed in layers, intermixed with areolar tissue, blood-vessels, lymphatic ves- 982 
FEMALE ORGANS OF GENERATION. 
seis, and nerves. In the impregnated state the muscular tissue becomes more prom- 
inently developed, and is disposed in three layers-external, middle, and internal. 
The external layer is placed beneath the peritoneum, disposed as a thin plane on 
the anterior and posterior surfaces. It consists of fibres which pass transversely 
across the fundus, and, converging at each superior angle of the uterus, are contin- 
ued on the Fallopian tubes, the round ligament, and ligament of the ovary, some 
passing at each side into the broad ligament, and others running backward from the 
cervix into the recto-uterine ligaments. 
The middle layer of fibres presents no regularity in its arrangement, being dis- 
posed longitudinally, obliquely, and transversely. 
The internal or deep layer consists of circular fibres arranged in the form of two 
hollow cones, the apices of which surround the orifices of the Fallopian tubes, their 
bases intermingling with one another on the middle of the body of the uterus. At 
the cervix these fibres are disposed transversely, constituting the so-called internal 
and external sphincters of the os uteri. 
The mucous membrane is thin, smooth, and closely adherent to the subjacent 
tissue. It is continuous, through the fimbriated extremity of the Fallopian tubes, 
[Fig. 658. 
Ovarian Artery 
Dterin c/Artery 
The Ovarian, Uterine, and Vaginal Arteries (Hyrtl): a, ovarian artery; a' and branches to tube; b, branch to 
round ligament: c, branch to the fundus uteri; c', branches to ovary; d, branch to the side of the uterus, 
anastomosing with e, the uterine artery, a branch of f, the anterior division of the internal iliac; <7, vaginal 
arteries. A special branch of the uterine artery goes to the cervix, and, with its fellow of the opposite side, 
forms the " circular artery " at the isthmus. Note the free a nastomosis and tortuousness of all these vessels, 
and that they all reach the uterus, ovary, and tube by the broad ligament, h, azygos artery of vagina (Hart 
and Barbour).] 
with the peritoneum, and through the os uteri with the mucous membrane lining the 
vagina. 
In the body of the uterus it is smooth, soft, of a reddish color, lined by colum- 
nar ciliated epithelium, and presents, when viewed with a lens, the orifices of 
numerous tubular follicles arranged perpendicularly to the surface. They are of THE UTERUS. 
983 
small size in the unimpregnated uterus, but shortly after impregnation they become 
enlarged, elongated, presenting a contorted or waved appearance toward their closed 
extremities, which occasionally dilate into two or three sacculated pouches. The 
circular orifices of these glands may be seen on the inner surface of the mucous 
membrane, many of which during the early period of pregnancy are surrounded by 
a whitish ring formed of epithelium which lines the follicles. In the impregnated 
uterus the epithelium loses its ciliated character. 
In the cervix the mucous membrane between the rugse and around the os uteri 
is provided with numerous mucous follicles and glands. The small, transparent, 
vesicular elevations so often found within the os and cervix uteri are due to closure 
of the mouths of these follicles and their distension with their proper secretion. 
They are called the ovula of Naboth. The mucous membrane covering the lower 
half of the cervix presents numerous papillae, and the epithelium is stratified. [r] 
Vessels and Nerves.-The arteries [Fig. 658] of the uterus are the uterine, 
from the internal iliac, and the ovarian, from the aorta. They are remarkable for 
their tortuous course in the substance of the organ and for their frequent anasto- 
moses. The veins are of large size, and correspond with the arteries. In the impreg- 
nated uterus these vessels are termed the uterine sinuses, consisting of the lining 
membrane of the veins adhering to the walls of the canals channelled through the 
substance of the uterus. They terminate in the uterine plexuses. The lymphatics 
are of large size in the impregnated uterus, and terminate in the pelvic and lumbar 
glands. The nerves are derived from the inferior hypogastric and ovarian plexuses 
and from the third and fourth sacral nerves. 
The form, size, and situation of the uterus vary at different periods of life and under differ- 
ent circumstances. 
Zn the foetus the uterus is contained in the abdominal cavity, projecting beyond the brim of 
the pelvis. The cervix is considerably larger than the body. 
At puberty the uterus is pyriform in shape and weighs from eight to ten drachms. It has 
descended into the pelvis, the fundus being just below the level of the brim of this cavity. The 
arbor vitae is distinct, and extends to the upper part of the cavity of the organ. 
During menstruation the organ is enlarged and more vascular, its surfaces roundel-; the os 
externumis rounded, its labia swollen, and the lining membrane of the body thickened, softer, 
and of a darker color. According to J. Williams, at each recurrence of menstruation a molec- 
ular disintegration and softening of the superficial part of the mucous membrane takes place, 
which leads to its complete removal. At the cessation of the menstrual flow a rapid prolifera- 
tion of the cells of the deeper layers of the mucous membrane takes place, and a fresh uterine 
membrane is quickly formed. 
During pregnancy the uterus increases so as to weigh from one pound and a half to three 
pounds. It becomes enormously enlarged, and projects into the hypogastric and lower part of 
the umbilical regions. This enlargement, which continues up to the sixth month of gestation, 
is partially due to increased development of pre-existing and new-formed muscular tissue. The 
round ligaments are enlarged, and the broad ligaments become encroached upon by the uterus 
making its way between their laminae. The mucous membrane becomes more vascular, its 
mucous follicles and glands enlarged; the rugae and folds in the canal of the cervix become 
obliterated ; the blood and lymphatic vessels, as well as the nerves, according to the researches 
of Dr. Lee, greatly enlarged. 
After parturition the uterus nearly regains its usual size, weighing from two to three ounces, 
but its cavity is larger than in the virgin state; the external orifice is more marked and assumes 
a transverse direction ; its edges present a fissured surface ; its vessels are tortuous, and its mus- 
cular layers are more defined. 
In old age the uterus becomes atrophied and paler and denser in texture; a more distinct 
[' Dr. A. W. Johnstone of Danville, Kentucky {Brit. Gyncecol. Joum., ii. 292), has made some very 
important observations on the mucous membrane of the uterus. He calls it the "menstrual organ," 
and says that it is " not a mucous membrane, but belongs to the so-called adenoid tissues," and that 
menstruation is for it exactly what the lymph-stream is to the lymph-glands or the blood-current to 
the spleen. Like the testicles, tonsils, Peyer's patches, the thymus gland, and many hair-follicles, 
its functional activitv does not extend throughout life. The menstrual organ develops at puberty and 
declines at the menopause, its structure varying remarkably at these two periods from that of its 
active functional life. At each menstruation the epithelium of the body of the uterus is shed, thus 
preparing a nidus for the impregnated ovum, while that of the cervix and tubes is not shed, and an 
impregnated ovum will not therefore adhere to it. In salpingitis, etc., if the mucous membrane is 
lost, an impregnated ovum may adhere and produce tubal pregnancy (Tait). J. Bland Sutton's 
paper on "Menstruation in Monkeys" immediately precedes Dr. Johnstone's important contribution, 
and confirms it to a remarkable degree.] 984 
FEMALE ORGANS OF GENERATION. 
constriction separates the body and cervix. The ostium internum, and, occasionally, the vaginal 
orifice, often become obliterated and its labia almost entirely disappear. 
Appendages of the Uterus. 
The appendages of the uterus are the Fallopian tubes, the ovaries and their lig- 
aments, and the round ligaments. These structures, together with their nutrient 
vessels and nerves and some scattered muscular fibres, are enclosed between the 
two folds of peritoneum which constitute the broad ligaments; they are placed in 
the following order: in front is the round ligament; the Fallopian tube occupies 
the free margin of the broad ligament; the ovary and its ligament are behind and 
below the latter. 
The Fallopian Tubes, or Oviducts, convey the ova from the ovaries to the 
cavity of the uterus. They are two in number, one on each side, situated in the 
free margin of the broad ligament, extending from each superior angle of the uterus 
to the sides of the pelvis. Each tube is about four inches in length; its canal is 
exceedingly minute, and commences at the superior angle of the uterus by a minute 
orifice, the ostium internum, which will hardly admit a fine bristle; it continues 
narrow along the inner half of the tube, and then gradually widens into a trumpet- 
shaped extremity which becomes contracted at its termination. This orifice is called 
the ostium abdominale, and communicates with the peritoneal cavity. Its margins 
are surrounded by a series of fringe-like processes, termed fimbrice, and one of these 
processes is connected with the outer end of the ovary. To this part of the tube the 
name fimbriated extremity is applied; it is also called morsus diaboli, from the pecu- 
liar manner in which it embraces the surface of the ovary during sexual excitement. 
In connection with the fimbriae of the Fallopian tube or with the broad ligament 
close to them there is frequently a small vesicle or hydatid, floating on a long stalk 
of peritoneum. 
Structure.-The Fallopian tube consists of three coats-a serous, muscular, and 
mucous. 
The external or serous coat is derived from the peritoneum. 
The middle or muscular coat consists of an external longitudinal and an inter- 
nal circular layer of muscular fibres continuous with those of the uterus. 
The internal or mucous coat is continuous with the mucous lining of the uterus, 
and at the free extremity of the tube with the peritoneum. It is thrown into longi- 
tudinal folds in the outer part of the tube, which indicate its adaptation for dilata- 
tion, and is covered by a columnar ciliated epithelium. This form of epithelium is 
also found on the inner surface of the fimbriae, while on the outer or serous surfaces 
of these processes the epithelium gradually merges into the pavement epithelium of 
the peritoneum. 
[The Fallopian tubes of late have been shown to be the frequent seat of inflam- 
mation (salpingitis), followed by local dropsy (hydrosalpinx), or accumulations of 
pus (pyosalpinx), or of blood (hemato-salpinx). Laparotomy often has to be resorted 
to for the relief of such diseases.] 
The Ovaries (testes muliebres, Galen) are analogous to the testes in the male. 
They are oval-shaped bodies of an elongated form, flattened from above downward, 
situated one on each side of the uterus in the posterior part of the broad ligament 
behind and below the Fallopian tubes. Each ovary is connected by its anterior 
margin to the broad ligaments; by its inner extremity to the uterus by a proper 
ligament, the ligament of the ovary ; and by its outer end to the fimbriated extrem- 
ity of the Fallopian tube by a short ligamentous cord. The ovaries are of a whitish 
color and present either a smooth or puckered uneven surface. They are each about 
an inch and a half in length, three-quarters of an inch in width, and about a third 
of an inch thick, and weigh from one to two drachms. The surfaces and posterior 
convex border are free, the anterior straight border being attached to the broad 
ligament. 
Professor His has described the position of the ovary with its long diameter THE UTERUS. 
985 
almost vertical and the Fallopian tube as running along its upper extremity, and 
then taking a sudden turn downward over the outer border of the ovary to below 
the level of its lower extremity. From this point the fimbriae are directed upward, 
[Fig. 659. 
Posterior View of Uterine Appendages: 1, uterus: 2, Fallopian tube; 3, fimbriated extremity and opening of the 
Fallopian tube; 4, epobphoron; 5, ovary; 6, ligament; 7, ligament of the ovary; 8, infundibulo-pelvie (broad) 
ligament (Henle). Compare Fig. 110, p. 136, and Fig. 657, p. 980.] 
and the ovary rests upon them. From this description it would appear that the ripe 
ova, when liberated from the ovary, would drop at once into the tube. 
Structure.-The ovary consists of a number of Graafian vesicles imbedded in 
the meshes of a stroma or framework, and invested by a serous covering derived 
from the peritoneum. 
Serous Covering.-Though the investing membrane of the ovary is derived from 
the peritoneum, it differs essentially from that structure, inasmuch as its epithelium 
consists of a single layer of columnar cells, instead of the flattened endothelial cells 
of other parts; this has been termed the germinal epithelium of Waldeyer, and 
Fig. 660. 
Bristle passed through 
Ostium abd. 
The Uterus and its Appendages, anterior view. 
gives to the surface of the ovary a dull gray aspect instead of the shining smooth- 
ness of serous membranes generally. 
Stroma.-The stroma is a peculiar soft tissue abundantly supplied with blood- 986 
FEMALE ORGANS OF GENERATION. 
vessels, consisting for the most part of spindle-shaped cells, with a small amount 
of ordinary connective tissue. These cells have been regarded by some anatomists 
as unstriped muscle-cells, which, indeed, they most resemble (His); by others as con- 
nective-tissue cells (Waldeyer, Henle, and Kblliker). On the surface of the organ 
this tissue is much condensed, and forms a layer composed of short connective-tj&sue 
fibres, with fusiform cells between them. This was formerly regarded as a distinct 
fibrous covering, and was termed the tunica albuginea, but is nothing more than a 
condensed layer of the stroma of the ovary. 
Graafian Vesicles.-Upon making a section of an ovary numerous round trans- 
parent vesicles of various sizes are to be seen; they are the Grrctafian vesicles, the 
ovisacs containing the ova. Immediately beneath the superficial covering is a layer 
of stroma, in which are a large number 
of minute vesicles of uniform size about 
of an inch in diameter. These are 
the Graafian vesicles in their earliest 
condition, and the layei' where they are 
found has been termed the cortical 
layer. They are especially numerous 
Fig. 661. 
Fig. 662. 
Ow.m, 
Onyi\.Zone 
Teritcneun ■ 
Section of the Ovary (after Schron): 1, outer covering; 
1', attached border; 2, central stroma; 3, peripheral 
stroma; 4, blood-vessels; 5, Graafian follicles in their 
earliest stage; 6,7, 8, more advanced follicles; 9, an 
almost mature follicle; 9', follicle from which the ovum 
has escaped; 10, corpus luteum. 
Sfrona of the'ovary 
Hid. hLaadf yececha 
coo:, of the Chef-Vic ¥ 
Nemir ana/ 
CrcuLulQAa 
Section of the Graafian Vesicle (after 
Von Baer). 
in the ovary of the young child. After puberty and during the whole of the child- 
bearing period large and mature (or almost mature) Graafian vesicles are also found 
in the cortical layer in small numbers, and also "corpora lutea," the remains of 
vesicles which have burst and are undergoing atrophy and absorption. Beneath 
this superficial stratum other larger and more mature Graafian vesicles are found 
imbedded in the ovarian stroma. These increase in size as they recede from the 
surface toward a highly vascular stroma in the centre of the organ, termed the 
medullary substance (zona vasculosa, Waldeyer). This stroma forms the tissue of 
the hilum by which the ovary is attached and through which the blood-vessels 
enter; it does not contain any Graafian vesicles. 
The Graafian vesicles consist of an external fibro-vascular coat connected with 
the surrounding stroma of the ovary by a network of blood-vessels, and an internal 
coat, named ovicapsule, which is lined by a layer of nucleated cells, called the mem- 
brana granulosa. The fluid contained in the interior of the vesicles is transparent 
and albuminous, and in it is suspended the ovum. In that part of the mature Graaf- 
ian vesicle which is nearest the surface of the ovary the cells of the membrana 
granulosa are collected into a mass which projects into the cavity of the vesicle. 
This is termed the discus proligerus, and in this the ovum is imbedded.1 
The ova are formed from the germ-epithelium on the surface of the ovary: the 
cells become enlarged and involuted, forming little depressions on the surface of the 
ovary. As they sink deeper into the tissue they become enclosed by the outgrowth 
of processes from the stroma of the ovary, and, becoming surrounded, their connec- 
tion with the surface is cut off' and the germ-epithelium forming the involution is 
contained in a cavity, the future Graafian follicle. The germ-cell or cells now form 
the ovum; the cell-wall forms the vitelline membrane; the nucleus, the germinal 
1 For a description of the ovum see p. 99. THE UTERUS. 
987 
area; and a nucleolus, which soon appears, the germinal spot. A clear homogene- 
ous protoplasm is formed within the cell, constituting the yolk, and thus the primor- 
dial ovum is developed. According to Dr. Foulis, the cells of the membrana granu- 
losa are formed out of the nuclei of the fibro-cellular stroma of the ovary.1 
The formation, development, and maturation of the Graafian vesicles and ova 
continue uninterruptedly from infancy to the end of the fruitful period of woman's 
life. Before puberty the ovaries are small; the Graafian vesicles contained in them 
are disposed in a comparatively thick layer in the cortical substance; here they 
present the appearance of a large number of minute closed vesicles, constituting 
the early condition of the Graafian vesicle; many, however, never attain full devel- 
opment, but shrink and disappear, their ova being incapable of impregnation. At 
puberty the ovaries enlarge, are more vascular, the Graafian vesicles are developed 
in greater abundance, and their ova are capable of fecundation. 
Discharge of the Ovum.-The Graafian vesicles, after gradually approaching 
the surface of the ovary, burst: the ovum and fluid contents of the vesicles are lib- 
erated, and escape on the exterior of the ovary, passing thence into the Fallopian 
tube, the fimbriated processes of which are supposed to grasp the ovary, the aperture 
of the tube being applied to the part corresponding to the matured and bursting 
vesicle. In the human subject and most Mammalia the maturation and discharge of 
the ova occur at regular periods only, and are indicated in the Mammalia by the 
phenomena of heat or rut, and in the human female by menstruation. [See footnote 
p. 983.] Sexual desire is more intense in females [of the lower animals] at this 
period, and if the union of the sexes takes place the ovum may be fecundated. 
Corpus Luteum.-Immediately after the rupture of a Graafian vesicle and the 
escape of its ovum the vesicle is filled with blood-tinged fluid, and in a short time 
the circumference of the vesicle is occupied by a firm yellow substance which is prob- 
ably formed from plasma exuded from its walls. Dr. Lee believes that this yellow 
matter is deposited outside both the membranes of the follicle ; Montgomery regards 
it as placed between the layers; while Kolliker considers it as a thickening of the 
inner layer of the outer coat of the follicle. The exudation is at first of a dark- 
brown or brownish-red color, but it soon becomes paler and its consistence more 
dense. 
For every follicle in the ovary from which the ovum is discharged a corpus luteum 
will be found. But the characters it exhibits and the changes produced in it will be 
determined by the circumstance of the ovum being impregnated or not. 
Although there is little doubt that corpora lutea exist in the ovaries after the 
escape of ova independently of coitus or impregnation, it appears that the corpus 
luteum of pregnancy (true corpus luteum) possesses characters by which it may be 
distinguished from one formed in a follicle from which an ovum has been discharged 
without subsequent impregnation (false corpus luteum). 
The true corpora lutea are of large size-often as large as a mulberry-of a 
rounded form, and project from the surface of the ovary, the summit of the projec- 
tion presenting a triangular depression or cicatrix where the peritoneum appears to 
have been torn. They contain a small cavity in their centre during the early period 
of their formation, which becomes contracted and exhibits a stellate cicatrix during 
the later stages of pregnancy. Their vascularity, lobulated or puckered appearance, 
firm consistence, and yellow color are also characteristic marks of tiue corpora 
lutea. 
False corpora lutea are of small size, do not project from the surface of the ovary, 
are angular in form, seldom present any cicatrix, contain no cavity in their centre; 
the material composing them is not lobulated, its consistence is usually soft, often 
resembling coagulated blood; the yellow matter exists in the form of a very thin 
layer, or more commonly is entirely wanting. False corpora lutea most frequently 
result from the effusion into the cavities of the Graafian vesicles of serum or blood, 
which subsequently undergoes various changes and is ultimately removed. Dr. Lee 
states that in the false corpora lutea the yellow substance is contained within or 
1 Proceedings of the Royal Society of Edinburgh, April, 1875. 988 
FEMALE ORGANS OF GENERATION. 
attached to the inner surface of the Graafian vesicle, and does not surround it, as is 
the case in the true corpora lutea. 
In the foetus the ovaries, like the testes, are situated in the lumbar region, near 
the kidneys. They may be distinguished from those bodies at an early period by 
their elongated and flattened form, and by their position, which is at first oblique 
and then nearly transverse. They gradually descend into the pelvis. 
Lying above the ovary in the broad ligament between it and the Fallopian tube 
is the organ of Rosenmuller, called also the parovarium or epobphoron. This is the 
remnant of a foetal structure, the development of which has been described at a 
former page (p. 136). [See also Fig. 659, p. 985.] In the adult it consists of a 
few closed convoluted tubes lined with epithelium, some of them atrophied, and one 
usually distinguishable from the rest by ending in a bulbous or hydatid swelling. 
The parovarium is connected at its uterine extremity with the remains of the 
Wolffian duct-the duct of Gartner. 
The Ligament of the Ovary is a rounded cord which extends from each superior 
angle of the uterus to the inner extremity of the ovary; it consists of fibrous tissue 
and a few muscular fibres derived from the uterus. 
The Round Ligaments are two rounded cords, between four and five inches in 
length, situated between the layers of the broad ligament, in front of and below the 
Fallopian tube. Commencing on each side at the superior angle of the uterus, this 
ligament passes forward and outward through the internal abdominal ring, along the 
inguinal canal to the labia majora, in which it becomes lost. The round ligament 
consists of areolar tissue, vessels, and nerves, besides a dense bundle of fibrous tissue 
and muscular fibres prolonged from the uterus, enclosed in a duplicature of peri- 
toneum, which in the foetus is prolonged in the form of a tubular process for a short 
distance into the inguinal canal. This process is called the canal of Nuck. It is 
generally obliterated in the adult, but sometimes remains pervious even in advanced 
life. It is analogous to the peritoneal pouch which accompanies the descent of the 
testis. 
Vessels and Nerves.-The arteries of the ovaries and Fallopian tubes are the 
ovarian, from the aorta. They anastomose with the termination of the uterine 
arteries, and enter the attached border of the ovary. The veins follow the course of 
the arteries; they form a plexus near the ovary, the pampiniform plexus. The 
nerves are derived from the inferior hypogastric or pelvic plexus and from the 
ovarian plexus, the Fallopian tube receiving a branch from one of the uterine 
nerves. 
Mammary Glands. 
The Mammae, or breasts, are accessory glands of the generative system, and 
secrete the milk. They exist in the male as well as in the female, but in the former 
only in the rudimentary state, unless their growth is excited by peculiar circum- 
stances. [Very rarely in the male, but very frequently in the female, they are the 
seat of carcinomatous and other tumors.] In the female they are two large hemi- 
spherical eminences situated toward the lateral aspect of the pectoral region, corre- 
sponding to the intervals between the third and sixth or seventh ribs, and extending 
from the side of the sternum to the axilla. [Occasionally, but very rarely, super- 
numerary breasts exist.] Their weight and dimensions differ at different periods of 
life and in different individuals. Before puberty they are of small size, but enlarge 
as the generative organs become more completely developed. They increase during 
pregnancy, and especially after delivery, and become atrophied in old age. The left 
mamma is generally a little larger than the right. Their base is nearly circular, 
flattened or slightly concave, and has its long diameter directed upward and outward 
toward the axilla; they are separated from the Pectoral muscles by a thin layer of 
superficial fascia. The outer surface of the mamma is convex, and presents just 
below the centre a small conical prominence, the nipple {mammilla). The surface of 
the nipple is dark-colored and surrounded by an areola having a colored tint. In 
the virgin the areola is of a delicate rosy hue ; about the second month of impregna- MAMMARY GLANDS. 
989 
tion it enlarges and acquires a darker tinge, which increases as pregnancy advances, 
becoming in some cases of a dark-brown or even black color. This color diminishes 
as soon as lactation is over, but is never entirely lost through life. These changes 
in the color of the areola are of extreme importance in forming a conclusion in a 
case of suspected first pregnancy. 
The Nipple is a cylindrical or conical eminence capable of undergoing a sort of 
erection from mechanical excitement-a change mainly due to the contraction of its 
muscular fibres. It is of a pink or brownish hue, its surface wrinkled and provided 
with papillae, and it is perforated by numerous orifices, the apertures of the lactifer- 
ous ducts. Near the base of the nipple and upon the surface of the areola are 
numerous sebaceous glands, which become much enlarged during lactation, and 
present the appearance of small tubercles beneath the skin. These glands secrete 
a peculiar fatty substance which serves as a protection to the integument of the 
nipple in the act of sucking. The nipple consists of numerous vessels, intermixed 
with plain muscular fibres which are principally arranged in a circular manner 
around the base, some few fibres radiating from base to apex. 
Structure.-The mamma consists of gland-tissue, of fibrous tissue connecting 
its lobes, and of fatty tissue in the intervals between the lobes. The mammary 
gland when freed from cellular tissue and fat is of a pale reddish color, firm in tex- 
ture, circular in form, flattened from before backward, thicker in the centre than at 
the circumference, and presenting several inequalities on its surface, especially in 
front. It consists of numerous lobes, and these are composed of lobules connected 
together by areolar tissue, blood-vessels, and ducts. The smallest lobules consist 
of a cluster of rounded vesicles which open into the smallest branches of the lac- 
tiferous ducts; these ducts, uniting, form larger ducts, which terminate in a single 
canal, corresponding with one of the chief subdivisions of the gland. The number 
of excretory ducts varies from fifteen to twenty: they are termed the tubuli lactiferi 
or galactophori. They converge toward the areola, beneath which they form dila- 
tations or ampulice, which serve as reservoirs for the milk, and at the base of the 
nipple become contracted and pursue a straight course to its summit, perforating it 
by separate orifices considerably narrower than the ducts themselves. The ducts 
are composed of areolar tissue, with longitudinal and transverse elastic fibres and 
longitudinal muscular fibres; their mucous lining is continuous at the point of the 
nipple with the integument. The epithelium of the mammary gland differs accord- 
ing to the state of activity of the organ. In the resting gland-that is to say, in 
the gland of a woman who is not pregnant or suckling-the alveoli are very small 
and solid, being filled with a mass of granular polyhedral cells. During pregnancy 
the alveoli enlarge and the cells undergo rapid multiplication. At the commence- 
ment of lactation the cells in the centre of the alveolus undergo fatty degeneration, 
and are eliminated in the first milk as colostrum corpuscles. The peripheral cells 
of the alveolus remain, and form a single layer of granular, short, columnar cells, 
with a spherical nucleus, lining the limiting membrana propria. These cells during 
the state of activity of the gland are capable of forming in their interior oil-glob- 
ules, which are then ejected into the lumen of the alveolus and constitute the milk- 
globules. 
The fibrous tissue invests the entire surface of the breast, and sends down septa 
between its lobes, connecting them together. 
The fatty tissue surrounds the surface of the gland, and occupies the intervals 
between' its lobes and lobules. It usually exists in considerable abundance, and 
determines the form and size of the gland. There is no fat immediately beneath 
the areola and nipple. 
Vessels and Nerves.-The arteries supplying the mammae are derived from 
the thoracic branches of the axillary, the intercostals, and the internal mammary. 
The wcms describe an anastomotic circle round the base of the nipple, called by 
Haller the circulus venosus. From this large branches transmit the blood to the 
circumference of the gland, and end in the axillary and internal mammary veins. 
The lymphatics, for the most part, run along the lower border of the Pectoralis 990 
FEMALE ORGANS OF GENERATION. 
major to the axillary glands. [These are especially important from the frequent 
occurrence of carcinoma in the breast.] Some few from the inner side of the 
breast perforate the intercostal spaces and empty themselves into the anterior 
mediastinal glands. The nerves are derived from the anterior and lateral cutaneous 
nerves of the thorax. The Surgical Anatomy of Inguinal Hernia. 
Dissection (Fig. 663).-For dissection of the parts concerned in inguinal hernia a male subject 
free from fat should always be selected. The body should be placed in the supine position, the 
abdomen and pelvis raised by means of blocks placed beneath them, and the lower extremities 
rotated outward, so as to make the parts as tense as possible. If the abdominal walls are flaccid, 
the cavity of the abdomen should be inflated by an aperture through the umbilicus. An incision 
should be made along the middle line from the umbilicus to the pubes, and continued along the 
front of the scrotum, and a second incision from the anterior superior spine of the ilium to just 
below the umbilicus. These incisions should divide the integument, and the triangular-shaped 
flap included between them should be reflected downward and outward, when the superficial 
fascia will be exposed. 
The Superficial Fascia in this region consists of two layers, between which are 
found the superficial vessels and nerves and the inguinal lymphatic glands. 
The superficial layer is thick, areolar in texture, containing adipose tissue in its 
meshes, the quantity of which varies in different subjects. Below, it passes over 
Poupart's ligament, and is continuous with the outer layer of the superficial fascia 
of the thigh. This fascia is continued as a tubular prolongation around the outer 
surface of the cord and testis. In this situation it changes its character; it becomes 
thin, destitute of adipose tissue, and of a pale reddish color, and assists in forming 
the dartos. From the scrotum it may be traced backward to be continuous with 
the superficial fascia of the perineum. This layer should be removed, by dividing 
it across in the same direction as the external incisions and reflecting it downward 
and outward, when the following vessels and nerves will be exposed: The superficial 
epigastric, superficial circumflex iliac, and superficial external pudic vessels, the ter- 
minal filaments of the hypogastric branch of the ilio-hypogastric nerve, and the 
upper chain of inguinal lymphatic glands. 
The superficial epigastric artery crosses Poupart's ligament, and ascends ob- 
liquely toward the umbilicus, lying midway between the spine of the ilium and the 
pubes. It supplies the integument and anastomoses with the deep epigastric. This 
vessel is a branch of the common femoral artery, and passes through the saphenous 
opening of the fascia lata. Its accompanying vein empties itself into the internal 
saphenous after having pierced the cribriform fascia. 
The superficial circumflex iliac artery passes outward toward the crest of the 
ilium, generally lying below the level of Poupart's ligament, and sending only a 
few branches upward to the abdomen. 
The superficial external pudic artery passes transversely inward across the sper- 
matic cord, and supplies the integument of the hypogastric region and of the penis 
and scrotum. This vessel is usually divided in the first incision made in the opera- 
tion for inguinal hernia, and occasionally requires the application of a ligature. 
The veins accompanying these superficial vessels are usually much larger than 
the arteries: they terminate in the internal saphenous vein. 
Lymphatic vessels are found, taking the same course as the blood-vessels: they 
return the lymph from the superficial structures in the lower part of the abdomen, 
the scrotum, penis, mucous membrane of the urethra, perineal and gluteal regions, 
and terminate in a small chain of lymphatic glands, three or four in number, which 
lie on a level with Poupart's ligament. 
Nerves.-The hypogastric branch of the ilio-hypogastric nerve perforates the 
aponeurosis of the external oblique above and to the outer side of the external ring, 
and is distributed to the integument covering the hypogastric region. The ilio- 
inguinal nerve may also be seen emerging at the external abdominal ring and pass- 
ing down to supply the skin of the scrotum and inner side of the thigh. 
The deep layer of superficial fascia should be divided across in the same direc- 
tion as the external incisions, separated from the aponeurosis of the External oblique, 
991 992 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
to which it is connected by delicate areolar tissue, and reflected downward and out- 
ward. It is thin, aponeurotic in structure, and of considerable strength. It is 
intimately adherent in the middle line to the linea alba, and below to the whole 
length of Poupart's ligament and the upper part of the fascia lata. It forms a thin 
tubular prolongation round the outer surface of the cord, and is continuous with the 
dartos of the scrotum. From the back of the scrotum it may be traced into the 
perineum, where it is continuous with the deep layer of the superficial fascia in that 
region, which is attached behind to the triangular ligament and on each side to the 
ramus of the pubes and ischium. The connections of this fascia serve to explain 
the course taken by the urine in extravasation of that fluid from rupture of the 
urethra: passing forward from the perineum into the scrotum, it ascends on to the 
Fig. 663. 
SU/Witfcidl I 
CiTCtirnftexl 
Hit V. [ 
External 
Abdominai Ring 
Superficial Epigastric V. 
Inguinal Hernia, superficial dissection. 
abdomen, but is prevented extending into the thighs by the attachment of the fascia 
to the ramus of the pubes and ischium on each side, and to Poupart's ligament in 
front, and is prevented from passing on to the buttock by the posterior connections 
of the perineal fascia. 
The aponeurosis of the External oblique muscle is exposed on the removal 
of this fascia. It is a thin, strong, membranous aponeurosis, the fibres of which are 
directed obliquely downward and inward. It is attached to the anterior superior 
spinous process of the ilium, the spine of the pubes, the linea ilio-pectinea, symphy- 
sis pubis, and linea alba. That portion of the aponeurosis which extends from the 
anterior superior spine of the ilium to the spine of the pubes is termed Poupart's 
ligament or the erural arch [Fig. 671, p. 1006]. From its attachment to the spine THE EXTERNAL ABDOMINAL RING. 
993 
of the pubes a portion of the aponeurosis is reflected downward and outward to be 
inserted into the pectineal line: this is termed G-imbernat's ligament. 
The External Abdominal Ring-.-Just above and to the outer side of the crest 
of the pubes an interval is seen in the aponeurosis of the External oblique, called 
the external abdominal ring. This aperture is oblique in direction, somewhat trian- 
gular in form, and corresponds with the course of the fibres of the aponeurosis. It 
usually measures from base to apex about an inch, and transversely about half an 
inch. It is bounded below by the crest of the os pubis ; above by a series of curved 
fibres, the inter columnar, which pass across the upper angle of the ring, so as to 
increase its strength; and on either side by the free borders of the aponeurosis, 
which are called the columns or pillars of the ring. 
The external pillar, which at the same time is inferior from the obliquity of its 
direction, is the stronger; it is formed by that portion of Poupart's ligament which 
is inserted into the spine of the pubes; it is curved round the spermatic cord so as 
to form a kind of groove, upon which the cord rests. 
The internal or superior pillar is a broad, thin, flat band which interlaces with 
its fellow on the opposite side in front of the symphysis pubis, that of the right side 
being superficial. 
The external abdominal ring gives passage to the spermatic cord in the male and 
round ligament in the female; it is much larger in men than in women, on account 
of the large size of the spermatic cord, and hence the great frequency of inguinal 
hernia in men. [It is called a-"ring," because after a hernial protrusion occurs it 
really becomes circular, though not of that shape before.] 
The intercolumnar fibres are a series of curved tendinous fibres which arch across 
the lower part of the aponeurosis of the External oblique. They have received their 
name from stretching across between the two pillars [or columns] of the external 
ring; they increase the strength of the membrane which bounds the upper part of 
this aperture, and prevent the divergence of the pillars from one another. They 
are thickest below, where they are connected to the outer third of Poupart's liga- 
ment, and are inserted into the linea alba, describing a curve with the convexity 
downward. They are much thicker and stronger at the outer angle of the external 
ring than internally, and are more strongly developed in the male than in the female. 
These fibres are continuous with a thin fascia which is closely connected to the mar- 
gins of the external ring, and has received the name of the intercolumnar or exter- 
nal spermatic fascia; it forms a tubular prolongation around the outer surface of 
the cord and testis and encloses them in a distinct sheath. The sac of an inguinal 
hernia in passing through the external abdominal ring receives an investment from 
the intercolumnar fascia. 
[To examine the external ring, place the finger on the middle of the scrotum 
and push it upward into the ring, carrying before it the pouch of scrotum so formed. 
This examination the student should make whenever possible, both in persons who 
have no hernia, to get an idea of the normal condition of the ring and cord, and in 
those who have a hernia, in order to recognize the changes in this condition. In 
the female the examination of the ring is much less satisfactory.] 
The finger should be introduced a short distance into the external ring, and then, 
if the limb is extended and rotated outward, the aponeurosis of the External oblique, 
together with the iliac portion of the fascia lata, will be felt to become tense, and 
the external ring much contracted; if, on the contrary, the limb is flexed upon the 
pelvis and rotated inward, this aponeurosis will become lax, and the external ring 
sufficiently enlarged to admit the finger with comparative ease; hence the patient 
should always be put in the latter position when the taxis is applied for the reduc- 
tion of an inguinal hernia, in order that the abdominal walls may be as much 
relaxed as possible. 
The aponeurosis of the External oblique should be removed by dividing it across in the same 
direction as the external incisions, and reflecting it downward and outward; great care is requi- 
site in separating it from the aponeurosis of the muscle beneath. The lower part of the Internal 
oblique and the Cremaster are then exposed, together with the inguinal canal, which contains the 994 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
spermatic cord (Fig. 664). The mode of insertion of Poupart's and Gimbernat's ligaments into 
the pubes should also be examined. 
Poupart's ligament, or the femoral arch, extends from the anterior superior 
spine of the ilium to the spine of the pubes. It is also attached to the pecti- 
neal line to the extent of about an 
inch, forming Gimbernat's ligament. Its 
general direction is curved toward the 
thigh, where it is continuous with the 
fascia lata. Its outer half is rounded, 
oblique in its direction, and continuous 
with the iliac fascia. Its inner half 
gradually widens at its attachment to 
the pubes, is more horizontal in direc- 
tion, and lies beneath the spermatic cord. 
[In every case of hernia or other disease 
in this region the only safe way to deter- 
mine its real situation is to fix the bony 
attachments of the two ends of Poupart's 
ligament by touch. Its line should then 
be marked by an aniline ("indelible") 
pencil. .The eye is very apt to be de- 
ceived by the furrow of the groin caused 
by flexure at the hip-joint. This furrow 
is a little below Poupart's ligament, and 
is apt to mislead us as to whether a hernia 
is femoral or inguinal. Once that the 
line of Poupart's ligament is accurately 
fixed, as above, a hernia that emerges 
above that line must be inguinal, and 
one below it must be femoral.] 
Gimbernat's ligament [Figs. 671 
and 672, p. 1006] is that portion of the 
aponeurosis of the External oblique which 
is inserted into the pectineal line; it is 
thin, membranous in structure, triangular in shape, the base directed outward, the 
apex corresponding to the spine of the pubes. Its anterior margin is continuous 
with Poupart's ligament, and its posterior margin attached to the pectineal line. 
The triangular ligament is a band of tendinous fibres, of a triangular shape, 
which is attached by its apex to the reflected portion of Poupart's ligament along 
the pectineal line. It passes inward beneath the spermatic cord, and expands into a 
somewhat fan-shaped fascia, lying behind the inner pillar of the external abdominal 
ring and in front of the conjoined tendon, and interlaces with the ligament of the 
other side at the linea alba. 
The Internal oblique muscle has been described (p. 414). The part which is 
now exposed is partly muscular and partly tendinous in structure. Those fibres 
which arise from the outer half of Poupart's ligament are thin, pale in color, curve 
downward, and terminate in an aponeurosis which passes in front of the Rectus and 
Pyramidalis muscles, to be inserted into the crest of the os pubis and pectineal line 
to the extent of half an inch, in common with that of the Transversalis muscle, 
forming by their junction the "conjoined tendon." This tendon is placed behind 
Gimbernat's ligament and the external abdominal ring, being separated from them 
by the triangular ligament, and serves to strengthen what would otherwise be a very 
weak point in the abdominal wall. When a direct inguinal hernia passes through the 
external ring the conjoined tendon usually forms one of its coverings. 
The Cremaster is a thin muscular layer composed of a number of fasciculi 
which arise from the middle of Poupart's ligament at the inner side of the Internal 
Fig. 664. 
Inguinal Hernia, showing the Internal Oblique, 
Cremaster, and Spermatic Canal. THE CREMASTER. 
995 
oblique, being connected with that muscle and also occasionally with the Transver- 
salis. It passes along the outer side of the spermatic cord, descends with it through 
the external ring upon the front and sides of the cord, and forms a series of loops 
which differ in thickness and length in different subjects. Those at the upper part 
of the cord are exceedingly short, but they become in succession longer and longer, 
the longest reaching down as low as the testicle, where a few are inserted into the 
tunica vaginalis. These loops are united together by areolar tissue, and form a thin 
covering over the cord, the fascia cremasterica. The fibres ascend along the inner 
side of the cord, and are inserted by a small pointed tendon into the crest of the os 
pubis and front of the sheath of the Rectus muscle. It is supplied by the genital 
branch of the genito-crural nerve. [Part of this muscle is unstriped muscular fibre, 
but part consists of striped voluntary fibres. Many persons can voluntarily contract 
the muscle and elevate the testicle almost to the external ring. It responds also to 
mechanical irritation of the skin of the upper and inner thigh by drawing the finger 
or a pencil, etc. quickly across it, thus forming the "Cremaster reflex," analogous to 
the patellar and other similar reflexes. (See also p. 746.)] 
It will be observed that the origin and insertion of the Cremaster are precisely 
similar to those of the lower fibres of the Internal oblique. This fact affords an 
easy explanation of the manner in which the testicle and cord are invested by this 
muscle. At an early period of foetal life the testis is placed at the lower and back 
part of the abdominal cavity, but during its descent toward the scrotum, which takes 
place before birth, it passes beneath the arched border of the Internal oblique. In 
its passage beneath this muscle some fibres are derived from its lower part, which 
accompany the testicle and cord into the scrotum. [See p. 975 for the correct view 
of the Cremaster in relation to the descent of the testicle.] 
It occasionally happens that the loops of the Cremaster surround the cord, some 
lying behind as well as in front. It 
is probable that under these circum- 
stances the testis in its descent passed 
through instead of beneath the fibres 
of the Internal oblique. 
In the descent of an oblique in- 
guinal hernia, which takes the same 
course as the spermatic cord, the 
Cremaster muscle forms one of its 
coverings. This muscle becomes 
largely developed in case of hydro- 
cele and large old scrotal hernias. 
No such muscle exists in the female, 
but an analogous structure is devel- 
oped in those cases where an oblique 
inguinal hernia descends beneath 
the margin of the Internal oblique. 
The Internal oblique should be de- 
tached from Poupart's ligament, sepa- 
rated from the Transversalis to the same 
extent as in the previous incisions, and 
reflected inward on to the sheath of the 
Rectus (Fig. 665). The circumflex iliac 
vessels, which lie between these two mus- 
cles, form a valuable guide to their sepa- 
ration. 
The Transversalis muscle has 
been previously described (p. 415). 
Its lower portion is partly fleshy 
and partly tendinous in structure; 
this portion arises from the outer third of Poupart's ligament, and, arching down- 
ward and inward over the cord, terminates in an aponeurosis which is inserted into 
Fig. 665. 
Internal 
Abdominal 
I Ring 
E/itgartric 
Artery 
Inguinal Hernia, showing the Transversalis Muscle, the 
Transversalis Fascia, and the Internal Abdominal Ring. 996 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
the linea alba, the crest of the pubes, and the pectineal line to the extent of an inch, 
forming, together with the Internal oblique, the conjoined tendon. Between the 
lower border of this muscle and Poupart's ligament a space is left in which is seen 
the fascia transversalis. 
The Inguinal or Spermatic Canal contains the spermatic cord in the male and 
the round ligament in the female. It is an oblique canal about an inch and a half 
in length, directed downward and inward, and placed parallel with and a little above 
Poupart's ligament. It commences above at the internal abdominal ring, which is 
the point where the cord enters the spermatic canal, and terminates below at the 
external ring. It is bounded in front by the integument and superficial fascia, by 
the aponeurosis of the External oblique throughout its whole length, and by the 
Internal oblique for its outer third; behind, by the triangular ligament, the con- 
joined tendon of the Internal oblique and Transversalis, transversalis fascia, and 
the subperitoneal fat and peritoneum; above, by the arched fibres of the Internal 
oblique and Transversalis; below, by the union of the fascia transversalis with 
Poupart's ligament. That form of protrusion in which the intestine follows the 
course of the spermatic cord along the spermatic canal is called oblique inguinal 
hernia. 
The Fascia Transversalis is a thin aponeurotic membrane which lies between 
the inner surface of the Transversalis muscle and the peritoneum. It forms part of 
the general layer of fascia which lines the interior of the abdominal and pelvic cavi- 
ties, and is directly continuous with the iliac and pelvic fasciae. 
In the inguinal region the transversalis fascia is thick and dense in structure, and 
joined by fibres from the aponeurosis of the Transversalis, but it becomes thin and 
cellular as it ascends to the Diaphragm. Below, it has the following attachments: 
External to the femoral vessels it is connected to the posterior margin of Poupart's 
ligament, and is there continuous with the iliac fascia; internal to the vessels it is 
thin, and attached to the pubes and pectineal line behind the conjoined tendon, with 
which it is united; and, corresponding to the points where the femoral vessels pass 
into the thigh, this fascia descends in front of them, forming the anterior wall of the 
femoral sheath. 
The Internal Abdominal Ring is situated in the transversalis fascia, midway 
between the anterior superior spine of the ilium and the symphysis pubis, and about 
half an inch above Poupart's ligament. It is of an oval form, the extremities of the 
oval directed upward and downward, varies in size in different subjects, and is much 
larger in the male than in the female. It is bounded above and externally by the 
arched fibres of the Transversalis muscle, below and internally by the epigastric ves- 
sels. It transmits the spermatic cord in the male and the round ligament in the 
female, and from its circumference a thin, funnel-shaped membrane, the infundibu- 
liform fascia, is continued round the cord and testis, enclosing them in a distinct 
pouch. When the sac of an oblique inguinal hernia passes through the internal 
ring, the infundibuliform process of the transversalis fascia forms one of its coverings. 
Between the fascia transversalis and the peritoneum is a quantity of loose areolar 
tissue. In some subjects it is of considerable thickness and loaded with adipose tis- 
sue. Opposite the internal ring it is continued round the surface of the cord, form- 
ing a loose sheath for it. 
The epigastric artery bears a very important relation to the internal abdominal 
ring. This vessel lies between the transversalis fascia and peritoneum, and passes 
obliquely upward and inward from its origin from the external iliac to the margin 
of the sheath of the Rectus muscle. In this course it lies along the lower and inner 
margin of the internal ring and beneath the commencement of the spermatic cord, the 
vas deferens curving round it as it passes from the ring into the pelvis. 
The Peritoneum, corresponding to the inner surface of the internal ring, presents 
a well-marked depression, the depth of which varies in different subjects. A thin 
fibrous band is continued from it along the front of the cord for a variable distance, 
and becomes ultimately lost. This is the remains of the pouch of peritoneum which 
in the foetus accompanies the cord and testis into the scrotum, the obliteration of INGUINAL HERNIA. 
997 
which commences soon after birth. In some cases the fibrous band can only be 
traced a short distance, but occasionally it may be followed as a fine cord as far as 
the upper end of the tunica vaginalis. Sometimes the tube of peritoneum is only closed 
at intervals and presents a sacculated appearance, or a single pouch may extend 
along the whole length of the cord, which may be closed above, or the pouch may 
be directly continuous with the peritoneum by an opening at its upper part. 
[General Remarks upon Hernia.] 
[Herniae in different parts of the body (with the exception of ventral and diaphragm- 
atic herniae) are rendered possible by the necessity for openings in the abdominal 
walls, generally for the passage of certain structures out of or into the abdominal 
cavity-e. g. the spermatic cord, the femoral, umbilical, and other vessels. Inter- 
nal to all such openings is the peritoneum (Fig. 666, 1), and externally are the super- 
ficial fascia and skin (Fig. 666, 5 and 6). We have then three coverings-viz. per- 
itoneum, superficial fascia, and skin, common to all the usual varieties of hernia; 
and, as every hernia has six coverings, there remain but three coverings peculiar to 
each individual kind of hernia. 
In the passage of the structures above referred to through the abdominal wall 
there must be a canal, with an internal opening (Fig. 666, 2) and an external open- 
ing (Fig. 666, 4). Each of these openings in the normal condition is closed by a 
fascia or other tissue. These two fasciae, therefore, being pushed before a hernia, 
will form two of the peculiar coverings of each hernia. The third peculiar covering 
is found always in the canal (Fig. 666, 3). The following figure and table will be 
found very useful in remembering these various openings and coverings: 
Diagram of the Coverings of Herni.e. 
Coverings common to all Herniee. 
[Fig. 666. 
1 
Peritoneum. 
5 6 
Superficial 
Fascia. Skin. 
Internal External 
opening. opening. 
2 3 4 
Coverings peculiar to each Hernia. 
Table of the Peculiar Coverings of Hernia. 
Variety of 
Hernia. 
2. 
Internal Opening. 
3. 
Canal. 
4. 
External Opening. 
1. Oblique 
Inguinal 
("Internal abdominal ring 
4 closed by the 
(Infundibular fascia. 
Inguinal canal. 
Cremaster muscle. 
External abdominal ring 
closed by the 
Intercolumnar fascia. 
2. Direct 
Inguinal 
(Abnormal opening 
< closed by the 
( Transversalis fascia. 
Abnormal canal. 
Conjoined tendon. 
External abdominal ring 
closed by the 
Intercolumnar fascia. 
3. Femoral 
(Femoral ring 
•< closed by the 
(Septon crurale (or femoralef 
Femoral. 
Femoral sheath or fascia propria. 
Saphenous opening 
closed by the 
Cribriform fascia.] 
INGUINAL HERNIA. 
Inguinal Hernia is that form of protrusion which makes its way through the 
abdomen in the inguinal region. 
There are two principal varieties of inguinal hernia-external or oblique, and 
internal or direct. 998 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
External or oblique inguinal hernia, the more frequent of the two, takes the same 
oblique course as the spermatic cord. It is called external, from the neck of the sac 
being on the outer or iliac side of the epigastric artery. 
Internal or direct inguinal hernia does not follow the same course as the cord, 
but protrudes through the abdominal wall on the inner or pubic side of the epigastric 
artery. 
Oblique Inguinal Hernia. 
In oblique inguinal hernia the intestine escapes from the abdominal cavity at 
the internal ring, pushing before it a pouch of peritoneum which forms the hernial 
sac (Fig. 667, a). As it enters the inguinal canal it receives an investment from the 
Fjg. 667. 
SAC OF 
SAC OF 
HERNIA. 
TUNICA 
VAGINALIS 
TUNICA 
VAGINALIS 
TUNICA 
VAGINALI S 
A B G 
Varieties of Oblique Inguinal Hernia: a, common scrotal hernia, showing the relation of the sac to the tunica 
vaginalis, b, congenital hernia, the sac being continuous with the tunica vaginalis, c, infantile hernia, 
showing the relation of the sac to the tunica vaginalis, the latter being prolonged in front of the sac. 
subserous areolar tissue, and is enclosed in the infundibuliform process of the trans- 
versalis fascia. In passing along the inguinal canal it displaces upward the arched 
fibres of the Transversalis and Internal oblique muscles, and is surrounded by the 
fibres of the Cremaster. It then passes along the front of the cord, and escapes from 
the inguinal canal at the external ring, receiving investments from the intercolumnar 
fascia and also the superficial fascia and the integument. Lastly, it may descend 
into the scrotum. 
The coverings of this form of hernia, after it has passed through the external 
ring, are, from without inward, the integument, superficial fascia, intercolumnar fascia, 
Cremaster muscle, infundibuliform fascia, subserous areolar tissue, and peritoneum. 
This form of hernia lies in front of the vessels of the spermatic cord, and seldom 
extends below the testis, on account of the intimate adhesion of the coverings of the 
cord to the tunica vaginalis. 
The seat of stricture in oblique inguinal hernia is either at the external ring in 
the inguinal canal, caused by the fibres of the Internal oblique or Transversalis, or 
at the internal ring, most frequently in the latter situation. If it is situated at the 
external ring, the division of a few fibres at one point of its circumference is all 
that is necessary for the replacement of the hernia. If in the inguinal canal or at 
the internal ring, it may be necessary to divide the aponeurosis of the External 
oblique so as to lay open the inguinal canal. In dividing the stricture the direction 
of the incision should be upward. 
When the intestine passes along the inguinal canal, and, escaping from the exter- 
nal ring, passes into the scrotum, it is called complete oblique inguinal or scrotal her- 
nia. If the intestine does not escape from the external ring, but is retained in the 
inguinal canal, it is called incomplete inguinal hernia or bubonocele. In each of 
these cases the coverings which invest it will depend upon the extent to which it 
descends in the inguinal canal. DIRECT INGUINAL HERNIA. 
999 
There are two other varieties of oblique inguinal hernia-the congenital and 
infantile. 
Congenital hernia (Fig. 667, b) is liable to occur in those cases where the pouch 
of peritoneum which accompanies the cord and testis in its descent in the foetus 
remains unclosed and communicates directly with the peritoneum. The intestine 
descends along this pouch into the cavity of the tunica vaginalis and lies in contact 
with the testis. This form of hernia has no proper sac, being contained within the 
tunica vaginalis. 
In infantile hernia (encysted) (Fig. 667, c) the pouch of peritoneum forming the 
tunica vaginalis becomes obliterated at its upper part, generally at or near the 
external abdominal ring; below this the pouch does not become closed, but forms 
a large cavity in which the testicle is contained. The hernial sac descends along 
the inguinal canal, and enters the scrotum behind the tunica vaginalis. As it 
descends it becomes more or less completely invested by the posterior layer of the 
tunica vaginalis, from which it is separated by a little loose areolar tissue; so that 
in operating upon this variety of hernia three layers of peritoneum would require 
division, the first and second being the layers of the tunica vaginalis, the third the 
anterior layer of the hernial sac. 
Direct Inguinal Hernia. 
In direct inguinal hernia the protrusion makes its way through some part of the 
abdominal wall internal to the epigastric artery, and passes directly through the 
abdominal parietes and external ring. At the lower part of the abdominal wall is 
a triangular space (Hesselbach's triangle') bounded externally by the deep epigastric 
artery, internally by the margin of the Rectus muscle, below by Poupart's ligament 
[Fig. 672, p. 1006]. The conjoined tendon is stretched across the inner two-thirds 
of this space, the remaining portion of the space being filled in by the transversalis 
fascia. 
In some cases the hernial protrusion escapes from the abdomen on the outer side 
of the conjoined tendon, pushing before it the peritoneum, the subserous areolar 
tissue, and the transversalis fascia. It then enters the inguinal canal, passing along 
nearly its whole length, and finally emerges from the external ring, receiving an 
investment from the intercolumnar fascia. The coverings of this form of hernia are 
precisely similar to those investing the oblique form.1 
In other cases the intestine is either forced through the fibres of the conjoined 
tendon, or the tendon is gradually distended in front of it so as to form a complete 
investment for it. The intestine then enters the lower end of the inguinal canal, 
escapes at the external ring lying on the inner side of the cord, and receives addi- 
tional coverings from the superficial fascia and the integument. This form of hernia 
has the same coverings as the oblique variety, excepting that the conjoined tendon 
is substituted for the Cremaster, and the infundibuliform fascia is replaced by a part 
of the general fascia transversalis. 
The seat of stricture in both varieties of direct hernia is most frequently at the 
1 The difference between the position of the neck of the sac in these two forms of direct inguinal 
hernia has been referred, with some probability, to a difference in the relative positions of the oblit- 
erated hypogastric artery and the epigastric artery. The projection of the hypogastric artery toward 
the cavity of the abdomen produces two fossae in the peritoneum. When the course of the obliterated 
hypogastric artery corresponds pretty nearly with that of the epigastric-which is regarded as the 
normal arrangement-the bottom of the external fossa of the peritoneum corresponds to the position 
of the internal abdominal ring, and a hernia which distends and pushes out the peritoneum lining 
this fossa is an oblique hernia. When, on the other hand, the obliterated hypogastric artery lies 
considerably to the inner side of the epigastric, it divides the triangle of Hesselbach into two parts. 
In that case a hernia may distend and push out the peritoneum forming the bottom of the fossa 
bounded externally by the epigastric artery and internally by the obliterated hypogastric artery, and 
bv so doing will protrude the tissues which form the abdominal wall between the internal ring and 
the conjoined tendon. It will be a direct hernia, since the neck of the sac lies internal to the epi- 
gastric artery • but its coverings, as stated in the text, will be identical with those of the oblique form, 
with the insignificant difference that the covering from the transversalis fascia is taken from another 
portion of that fascia, and not from its infundibuliform piocess. 1000 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
neck of the sac or at the external ring. In that form of hernia which perforates 
the conjoined tendon it not unfrequently occurs at the edges of the fissure through 
which the gut passes. In dividing the stricture the incision should in all cases be 
directed upward.1 
If the hernial protrusion passes into the inguinal canal, but does not escape 
from the external abdominal ring, it forms what is called incomplete direct hernia. 
This form of hernia is usually of small size, and in corpulent persons very difficult 
of detection. 
Direct inguinal hernia is of much less frequent occurrence than the oblique, 
their comparative frequency being, according to Cloquet, as one to five. It occurs 
far more frequently in men than in women, on account of the larger size of the 
external ring in the former sex. It differs from the oblique in its smaller size and 
globular form, dependent most probably on the resistance offered to its progress by 
the transversalis fascia and conjoined tendon. It differs also in its position, being 
placed over the pubes and not in the course of the inguinal canal. The epigastric 
artery runs on the outer or iliac side of the neck of the sac, and the spermatic cord 
along its external and posterior side, not directly behind it, as in oblique inguinal 
hernia. 
SURGICAL ANATOMY OF FEMORAL HERNIA. 
The dissection of the parts comprised in the anatomy of femoral hernia should be performed, 
if possible, upon a female subject free from fat. The subject should lie upon its back ; a block 
is first placed under the pelvis, the thigh everted, and the knee slightly bent, and retained in 
this position. An incision should then be made from the anterior superior spinous process of 
the ilium along Poupart's ligament to the symphysis pubis; a second incision should be carried 
transversely across the thigh about six inches beneath the preceding; and these are to be con- 
nected together by a vertical one carried along the inner side of the thigh. These several 
incisions should divide merely the integument; this is to be reflected outward, when the super- 
ficial fascia will be exposed. 
[Consult General Remarks upon Hernia, and Fig. 666, p. 997.] 
The superficial fascia at the upper part of the thigh consists of two layers, 
between which are found the cutaneous vessels and nerves and numerous lymphatic 
glands. 
The superficial layer is a thick and dense fibro-cellular membrane, in the meshes 
of which is found a considerable amount of adipose tissue, varying in quantity in 
different subjects; this layer may be traced upward over Poupart's ligament to be 
continuous with the superficial fascia of the abdomen ; whilst below and on the 
inner and outer sides of the limb it is continuous with the superficial fascia cover- 
ing the rest of the thigh. 
This layer should be detached by dividing it across in the same direction as the external 
incisions ; its removal will be facilitated by commencing at the lower and inner angle of the 
space, detaching it at first from the front of the internal saphenous vein, and dissecting it off 
from the anterior surface of that vessel and its branches; it should then be reflected outward in 
the same manner as the integument. The cutaneous vessels and nerves and superficial inguinal 
glands are then exposed, lying upon the deep layer of the superficial fascia. These are the 
internal saphenous vein and the superficial epigastric, superficial circumflex iliac, and superficial 
external pudic vessels, as well as numerous lymphatics ascending with the saphenous vein to 
the saphenous glands. 
The internal saphenous vein is a vessel of considerable size which ascends 
obliquely upward along the inner side of the thigh. It passes through the saph- 
enous opening in the fascia lata to terminate in the femoral vein. This vessel is 
accompanied by numerous lymphatics, which return the lymph from the dorsum of 
1 In all cases of inguinal hernia, whether oblique or direct, it is proper to divide the stricture 
directly upward; the reason of this is obvious, for by cutting in this direction the incision is made 
parallel to the epigastric artery-either external to it in the oblique variety, or internal to it in the 
direct form of hernia-and thus all chance of wounding the vessel is avoided. If the incision was 
made outward, the artery might be divided if the hernia was direct, and if made inward it would 
stand an equal chance of injury if the case was one of oblique inguinal hernia. FEMORAL HERNIA. 
1001 
the foot and inner side of the leg and thigh : they terminate in the glands which 
surround the saphenous opening. Diverging from the same point are the super- 
ficial epigastric vessels, which run across Poupart's ligament obliquely upward and 
inward to the lower part of the abdomen; the superficial circumflex iliac vessels, 
which pass obliquely outward along Poupart's ligament to the crest of the ilium; 
and the superficial external pudic vessels, which pass inward to the perineum and 
scrotum. These vessels supply the subcutaneous areolar tissue and the integument, 
and are accompanied by numerous lymphatic vessels which return the lymph from 
the same parts to the inguinal glands. 
The superficial lymphatic glands are arranged in two groups, one of which is 
disposed above and parallel with Poupart's ligament, and the other below the lig- 
ament surrounding the termination of the saphenous vein, and following (occasion- 
ally) the course of that vessel a short distance along the thigh. The upper chain 
receives the lymphatic vessels from the genital organs, lower part of the abdomen, 
perineum, and buttock; the lower chain receives the lymphatic vessels from the 
lower extremity. 
The nerves supplying the integument of the region are derived from the ilio- 
inguinal, the genito-crural, and anterior crural. The ilio-inguinal nerve may be 
found on the inner side of the internal saphenous vein, the terminal branch of the 
genito-crural nerve outside the vein, and the middle and external cutaneous nerves 
more external. 
The deep layer of superficial fascia should be divided in the same direction as 
the external incisions, and separated from the fascia lata; this is easily effected to 
the inner side of the saphenous vein, when it forms a distinct though very thin 
membrane. External to the vein it can scarcely be separated as a continuous 
layer. It is placed beneath the subcutaneous vessels and nerves and upon the sur- 
face of the fascia lata. It is intimately adherent above to the lower margin of 
Poupart's ligament, and about one inch below this ligament covers the saphenous 
opening in the fascia lata, is closely united'to its circumference, and is connected to 
the sheath of the femoral vessels corresponding to its under surface. The portion 
of fascia covering this aperture is perforated by the internal saphenous vein, and 
by numerous blood- and lymphatic vessels; hence it has been termed the cribriform 
fascia, the openings of these vessels having been likened to the holes in a sieve. 
The cribriform fascia adheres closely both to the superficial fascia and the fascia 
lata, so that it is described by some anatomists as a part of the fascia lata, but is 
usually considered (as in this work) as belonging to the superficial fascia. It is not 
till the cribriform fascia has been cleared away that the saphenous opening is seen, 
so that this opening does not in ordinary cases exist naturally, but is the result of 
dissection. Mr. Callender, however, speaks of cases in which, probably as the 
result of pressure from enlarged inguinal glands, the fascia has become atrophied 
and a saphenous opening exists independent of dissection.1 A femoral hernia in 
passing through the saphenous opening receives the cribriform fascia as one of its 
coverings. 
The deep layer of superficial fascia, together with the cribriform fascia, having 
been removed, the fascia lata is exposed. 
The Fascia Lata, already described (p. 465), is a dense fibrous aponeurosis 
which forms a uniform investment for the whole of this region of the limb. At 
the upper and inner part of the thigh a large oval-shaped aperture is observed in it, 
which transmits the internal saphenous vein and other smaller vessels and is called 
the saphenous opening. In order the more correctly to consider the mode of for- 
mation of this aperture, the fascia'lata in this part of the thigh is described as con- 
sisting of two portions, an iliac portion and a pubic portion. 
The iliac portion of the fascia lata is situated on the outer side of the saphenous 
opening, covering the outer surface of the Sartorius, the Rectus, the Psoas, and the 
Iliacus muscles. It is attached externally to the crest of the ilium and its anterior 
superior spine, to the whole length of Poupart's ligament as far internally as the 
1 Anatomy of Femoral Rupture, note on p. 18. 1002 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
spine of the pubes, and to the pectineal line in conjunction with Gimbernat's liga- 
ment, where it becomes continuous with the pubic portion. From the spine of the 
pubes it is reflected downward and outward, forming an arched margin, the outer 
boundary (superior cornu) of the saphenous opening. This is sometimes called the 
falciform process of the fascia lata (femoral ligament of Hey); it overlies and is 
adherent to the sheath of the femoral vessels beneath; to its edge is attached the 
cribriform fascia, and it is continuous below with the pubic portion of the fascia 
lata by a well-defined curved margin.1 
The pubic portion of the fascia lata is situated at the inner side of the saphenous 
opening: at the lower margin of this aperture it is continuous with the iliac por- 
Fig. 668. 
Femoral Hernia, superficial dissection. 
tion : traced upward, it covers the surface of the Pectineus, Adductor longus, and 
Gracilis muscles; and, passing behind the sheath of the femoral vessels, to which it 
is closely united, is continuous with the sheath of the Psoas and Iliacus muscles, 
and is finally lost in the fibrous capsule of the hip-joint. This fascia is attached 
above to the pectineal line and internally to the margin of the pubic arch. It may 
be observed from this description that the iliac portion of the fascia lata passes in 
1 Mr. Gay (on Femoral Rupture, p. 13) describes the iliac portion of the fascia lata as advancing 
to the saphenous opening, then becoming abruptly reflected on itself, so as to form two layers, the 
inner or lower of which is continuous with the thin fascia repeatedly alluded to by Sir A. Cooper as 
spread out beneath it and in front of the sheath of the vessels. This deep layer of the iliac fascia is 
traversed by a band of ligamentous fibres lying immediately behind the crural [femoral] arch, and 
named the deep crural [or femoral] arch, which Mr. Gay identifies with Hey's ligament. FEMORAL HERNIA. 
1003 
front of the femoral vessels, the pubic portion behind them; an apparent aperture 
consequently exists between the two, through which the internal saphenous joins 
the femoral vein. 
The Saphenous Opening1 is an oval-shaped aperture measuring about an inch 
and a half in length and half an inch in width. It is situated at the upper and 
Fig. 669. 
Femoral Hernia, showing fascia lata and saphenous opening. 
inner part of the thigh, below Poupart's ligament, toward the inner side, and is 
directed obliquely downward and outward. [It is the external end of the femoral 
canal, and so is analogous to the "external ring" in inguinal hernia, the femoral 
ring being analogous to the "internal ring."] 
Its outer margin is of a semilunar form, thin, strong, sharply defined, and lies on 
a plane considerably anterior to the inner margin. If this edge is traced upward, it 
will be seen to form a curved elongated process or cornu (the superior cornu), ox fal- 
ciform process of Burns, which ascends in front of the femoral vessels, and, curving 
inward, is attached to Poupart's ligament and to the spine of the pubes and pectineal 
line, where it is continuous with the pubic portion.1 If traced downward, it is found 
1 Tt is difficult to perceive in the recognized description of these ligaments (Hey's and Burns's) 
any difference between the two, nor is it clear what structure Mr. Hey really intended to describe. 
Mr. Gay (on Femoral Rupture, p. 16) gives very cogent reasons for thinking that the "deep crural 
arch " was the structure which Hey had in view. The most recent writer on femoral hernia speaks 
thus while treating of these parts: " The whole upper edge of the iliac fascia lata is commonly 
called the 'falciform process,' whilst its deeper fibres receive the name of 'Burns's ligament.' Hey's 
femoral ligament would appear to consist of distinct fibres connected with the inner fold of the iliac 
fascia, which extend immediately beneath the tendon of the external oblique to the subperitoneal 
fascia" (Callender, On the Anatomy of the Parts concerned in Femoral Rupture, p. 19, note). This 
description of Hey's ligament accords closely with that of the deep femoral arch, for the subperito- 1004 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
continuous with another curved margin, the concavity of which is directed upward 
and inward: this is the inferior cornu of the saphenous opening, and is blended 
with the pubic portion of the fascia lata covering the Pectineus muscle. 
The inner boundary of the opening is on a plane posterior to the outer margin 
and behind the level of the femoral vessels; it is much less prominent and defined 
than the outer, from being stretched over the subjacent Pectineus muscle. It is 
through the saphenous opening that a femoral hernia passes after descending along 
the femoral canal. 
If the finger be introduced into the saphenous opening while the limb is moved in 
different directions, the aperture will be found to be greatly constricted on extending 
the limb or rotating it outward, and to be relaxed on flexing the limb and inverting 
it: hence the necessity for placing the limb in the latter position in employing the 
taxis for the reduction of a femoral hernia. 
The iliac portion of the fascia lata, but not its falciform process, should now be removed by 
detaching it from the lower margin of Poupart's ligament, carefully dissecting it from the sub- 
jacent structures, and turning it inward, when the sheath of the femoral vessels is exposed 
descending beneath Poupart's ligament (Fig. 670). 
Poupart's Ligament, or the Femoral Arch [see remarks on this ligament on 
p. 994. The adjective "crural" in relation to the anatomy of femoral hernia is 
being less and less used in this country : " femoral " is happily replacing it. I have 
therefore substituted it in this American edition in most places. The student, how- 
ever, must remember the use of "crural," or he will misunderstand much of the 
literature of femoral hernia], is the lower border of the aponeurosis of the External 
oblique muscle, which stretches across from the anterior superior spine of the ilium 
to the spine of the os pubis and pectineal line: the portion corresponding to the 
latter insertion is called G^imbernat, s ligament. The direction of Poupart's liga- 
ment is curved downward toward the thigh, its outer half being oblique, its inner 
half nearly horizontal. Nearly the whole of the space included between the fem- 
oral arch and innominate bone is filled in by the parts which descend from the 
abdomen into the thigh. The outer half of the' space is occupied by the Iliacus 
and Psoas muscles, together with the external cutaneous and anterior crural nerves. 
The pubic half of the space is occupied by the femoral vessels included in their 
sheath, a small oval-shaped interval existing between the femoral vein and the inner 
wall of the sheath, which is occupied merely by a little loose areolar tissue, and 
occasionally by a small lymphatic gland: this is the femoral ring, through which 
the gut descends in femoral hernia. 
Gimbernat's Ligament (Figs. 671 and 672) is that part of the aponeurosis of 
the External oblique muscle which is reflected downward and outward [from Pou- 
part's ligament] to be inserted into the pectineal line of the os pubis. It is about 
an inch in length, larger in the male than in the female, almost horizontal in direc- 
tion in the erect posture, and of a triangular form, the base directed outward. Its 
base or outer margin is concave, thin, and sharp, lies in contact with the femoral 
sheath, and is blended with the pubic portion of the fascia lata. Its apex corre- 
sponds to the spine of the pubes. Its posterior margin is attached to the pectineal 
line. Its anterior margin is continuous with Poupart's ligament. 
Femoral Sheath.-If Poupart's ligament be divided, the femoral sheath may be 
demonstrated as a continuation downward of the fasciae that line the abdomen, the 
transversalis fascia passing down in front of the femoral vessels and the iliac fascia 
descending behind them: these fasciae are directly continuous on the iliac side of 
the femoral artery, but a small space exists between the femoral vein and the point 
where they are continuous on the pubic side of that vessel, which constitutes the 
femoral or crural canal. The femoral sheath is closely adherent to the contained 
neal fascia is Mr. Callender's name for the fascia transversalis. Mr. Callender goes on to say: " The 
upper border of this (saphenous) opening thus receives, by an unfortunate complication, the names 
of 'falciform process,' 'femoral ligament,' 'Burns's or Hey's ligament.' The various divisions of the 
iliac fascia lata depend in great measure upon the skill of the dissector, and are, in my opinion, 
artificial." FEMORAL HERNIA. 
1005 
vessels about an inch below the saphenous opening, becoming blended with the 
areolar sheath of the vessels, but opposite Poupart's ligament it is much larger 
than is required to contain them; hence the funnel-shaped form which it presents. 
The outer border of the sheath is perforated by the genito-crural nerve. Its inner 
border is pierced by the internal saphenous vein and numerous lymphatic vessels. 
In front it is covered by the iliac portion of the fascia lata, and behind it is the 
pubic portion of the same fascia. 
Deep Femoral Arch.-Passing across the front of the femoral sheath, and 
closely connected with it, is a thickened band of fibres, called the deep femoral 
Fig. 670. 
Femoral Hernia, Iliac Portion of Fascia Lata removed and Sheath of Femoral Vessels and Femoral Canal 
exposed. 
arch. It is apparently a thickening of the fascia transversalis, joining externally 
to the centre of Poupart's ligament, and arching across the front of the femoral 
sheath to be inserted by a broad attachment into the pectineal line behind the con- 
joined tendon. In some subjects this structure is not very prominently marked, 
and not unfrequently it is altogether wanting. 
If the anterior wall of the sheath is removed, the femoral artery and vein are 
seen lying side by side, a thin septum separating the two vessels, while another 
septum may be seen lying just internal to the vein and cutting off a small space 
between the vein and the inner wall of the sheath. The septa are stretched between 
the anterior and posterior walls of the sheath, so that each vessel is enclosed in a 
separate compartment. The interval left between the vein and the inner wall of 
the sheath is not filled up by any structure, excepting a little loose areolar tissue, a 
few lymphatic vessels, and occasionally a lymphatic gland: this is the femoral or 
crural canal, through which the intestine descends in femoral hernia. 1006 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
Fig. 671. 
POUPART 5 
LIGAMENT 
CRURAL BR. 
OF GENITO- 
CRURAL 
ANT. CRURAL 
EXT. CUTANEOUS NERVE 
ILIAC PORTION 
OF FASCIA LATA 
SHEATH 
EEMORAL 
VEIN 
FEMORAL 
RING 
cimbernat's 
LIGAMENT 
PSOAS 
MAGNUS 
Structures which pass beneath the Femoral Arch [viewed from in front]. 
FEMORAL ARTERY 
The Femoral Canal is the narrow interval between the femoral vein and the 
inner wall of the femoral sheath. It exists as a distinct canal only when the sheath 
has been separated from the vein by dissection or by the pressure of a hernia or 
Fig. 672. 
Hernia, the relations of the Femoral and Internal Abdominal Rings, seen from within the abdomen, right side. FEMORAL HERNIA. 
1007 
tumor. Its length is from a quarter to half an inch, and it extends from Gimber- 
nat's ligament to the upper part of the saphenous opening. 
Its anterior wall is very narrow, and formed by a continuation downward of the 
fascia transversalis under Poupart's ligament, covered by the falciform process of 
the fascia lata. 
Its posterior wall is formed by a continuation downward of the iliac fascia, 
covering the pubic portion of the fascia lata. 
Its outer wall is formed by the fibrous septum separating it from the inner side 
of the femoral vein. 
Its inner wall is formed by the junction of the processes of the transversalis and 
iliac fasciae (which form the inner side of the femoral sheath) and lies in contact at 
its commencement with the outer edge of Gimbernat's ligament. 
This canal has two orifices-an upper one, the femoral or crural ring, closed by 
the septum crurale [or femorale] ; and a lower one, the saphenous opening, closed by 
the cribriform fascia. 
The Femoral (or Crural) Ring' (Figs. 671 and 672) is the upper opening of the 
femoral canal and leads into the cavity of the abdomen.1 It is bounded in front by 
Poupart's ligament and the deep femoral arch ; behind by the pubes, covered by the 
Pectineus muscle and the pubic portion of the fascia lata; internally by the base 
of Gimbernat's ligament, the conjoined tendon, the transversalis fascia, and the 
deep femoral arch ; externally by the fibrous septum lying on the inner side of the 
femoral vein. The femoral ring is of an oval form; its long diameter, directed 
transversely, measures about half an inch, and it is larger in the female than in the 
male [on account of the greater width of the female pelvis]; which is one of the 
reasons of the greater frequency of femoral hernia in the former sex. 
Position of Parts around the Ring.-The spermatic cord in the male and the 
round ligament in the female lie immediately above the anterior margin of the 
femoral ring, and may be divided in an operation for femoral hernia if the incision 
for the relief of the stricture is not of limited extent. In the female this is of 
little importance, but in the male the spermatic artery and vas deferens may be 
divided. 
The femoral vein lies on the outer side of the ring. 
The epigastric artery in its passage inward from the external iliac artery to the 
umbilicus passes across the upper and outer angle of the femoral ring, and is conse- 
quently in danger of being wounded if the stricture is divided in a direction upward 
and outward. 
The communicating branch between the epigastric and obturator lies in front of 
the ring. 
The circumference of the ring is thus seen to be bounded by vessels in every 
part, excepting internally and behind. It is in the former position that the stric- 
ture is divided in cases of strangulated femoral hernia. 
The obturator artery, when it arises by a common trunk with the epigastric- 
which occurs once in every three subjects and a half-bears a very important rela- 
tion to the femoral ring. In some cases it descends on the inner side of the exter- 
nal iliac vein to the obturator foramen, and will consequently lie on the outer side 
of the femoral ring, where there is no danger of its being wounded in the operation 
for dividing the stricture in femoral hernia. (See Fig. 401, A, p. 587.) Occa- 
sionally, however, the obturator artery curves along the free margin of Gimbernat's 
ligament in its passage to the obturator foramen; it would consequently skirt along 
the greater part of the circumference of the femoral canal, and could hardly avoid 
being wounded in the operation. (See Fig. 401, b, p. 587.) [To avoid this acci- 
dent the edge of the knife should be dulled, and the edge of Gimbernat's ligament 
only nicked and then torn.] 
Septum Crurale [or Femorale].-The femoral ring is closed by a layer of con- 
1 This ring, like the femoral canal, is a morbid or an artificial product. "Each femoral hernia 
makes for itself (for neither outlet exists in the natural anatomy of the region) a crural canal and a 
crural (femoral) ring" (Callender, op. tit., p. 40). 1008 
SURGICAL ANATOMY OF INGUINAL HERNIA. 
densed areolar tissue, called by J. Cloquet the septum crurale. This serves as a 
barrier to the protrusion of a hernia through this part. Its upper surface is slightly 
concave and supports a small lymphatic gland, by which it is separated from the 
subserous areolar tissue and peritoneum. Its under surface is turned toward the 
femoral canal. The septum crurale is perforated by numerous apertures for the 
passage of lymphatic vessels connecting the deep inguinal glands with those sur- 
rounding the external iliac artery. 
The size of the femoral canal, the degree of tension of its orifices, and conse- 
quently the degree of constriction of a hernia, vary according to the position of the 
limb. If the leg and thigh are extended, abducted, or everted, the femoral canal 
and its orifices are rendered tense from the traction on these parts by Poupart's lig- 
ament and the fascia lata, as may be ascertained by passing the finger along the 
canal. If, on the contrary, the thigh is flexed upon the pelvis, and at the same 
time adducted and rotated inward, the femoral canal and its orifices become con- 
siderably relaxed; for this reason the limb should always be placed in the latter 
position when the application of the taxis is made in attempting the reduction of a 
femoral hernia. 
The septum crurale is separated from the peritoneum by a quantity of loose sub- 
serous areolar tissue. In some subjects this tissue contains a considerable amount 
of adipose substance, which, when protruded forward in front of the sac of a femoral 
hernia, may be mistaken for a portion of omentum. 
Descent of the Hernia.-From the preceding description it follows that the 
femoral ring must be a weak point in the abdominal wall: hence it is that when 
violent or long-continued pressure is made upon the abdominal viscera a portion of 
intestine may be forced into it, constituting a femoral hernia; and the changes in 
the tissues of the abdomen which are produced by pregnancy, together with the 
larger size of this aperture in the female, serve to explain the frequency of this 
form of hernia in women. 
When a portion of the intestine is forced through the femoral ring, it carries 
before it a pouch of peritoneum, which forms what is called the hernial sac; it 
receives an investment from the subserous areolar tissue and from the septum crurale, 
and descends vertically along the femoral canal in the inner compartment of the 
sheath of the femoral vessels as far as the saphenous opening; at this point it 
changes its course, being prevented from extending farther down the sheath on 
account of the narrowing of the sheath and its close contact with the vessels, and 
also from the close attachment of the superficial fascia and femoral sheath to the 
lower part of the circumference of the saphenous opening ; the tumor is consequently 
directed forward, pushing before it the cribriform fascia, and then curves upward 
on to the falciform process of the fascia lata and lower part of the tendon of the 
External oblique, being covered by the superficial fascia and integument. While 
the hernia is contained in the femoral canal it is usually of small size, owing to the 
resisting nature of the surrounding.parts; but when it has escaped from the saph- 
enous opening into the loose areolar tissue of the groin it becomes considerably 
enlarged. The direction taken by a femoral hernia in its descent is at first down- 
ward, then forward and upward; this should be borne in mind, as in the applica- 
tion of the taxis for the reduction of a femoral hernia pressure should be directed 
ih the reverse order. 
Covering's of the Hernia.-The coverings of a femoral hernia from within 
outward are peritoneum, subserous areolar tissue, the septum crurale [femorale], 
femoral sheath, cribriform fascia, superficial fascia, and integument.1 
Varieties of Femoral Hernia.-If the intestine descends along the femoral 
1 Sir A. Cooper has described an investment for femoral hernia under the name of "fascia pro- 
pria," lying immediately external to the peritoneal sac, but frequently separated from it by more or 
less adipose tissue. Surgically, it is important to remember the existence (at any rate, the occasional 
existence) of this layer, on account of the ease with which an inexperienced operator may mistake 
the fascia for the peritoneal sac, and the contained fat for omentum. Anatomically, this fascia 
appears identical with what is called in the text "subserous areolar tissue," the areolar tissue being 
thickened and caused to assume a membranous appearance by the pressure of the hernia. FEMORAL HERNIA. 
1009 
canal only as far as the saphenous opening, and does not escape from this aperture, 
it is called incomplete femoral hernia. The small size of the protrusion in this form 
of hernia, on account of the firm and resisting nature of the canal in which it is con- 
tained, renders it an exceedingly dangerous variety of the disease, from the extreme 
difficulty of detecting the existence of the swelling, especially in corpulent subjects. 
The coverings of an incomplete femoral hernia would be, from without inward, integ- 
ument, superficial fascia, falciform process of fascia lata, femoral sheath, septum 
crurale [femorale], subserous areolar tissue, and peritoneum. When, however, the 
hernial tumor protrudes through the saphenous opening and directs itself forward 
and upward, it forms a complete femoral hernia. Occasionally the hernial sac 
descends on the iliac side of the femoral vessels or in front of these vessels, or 
even sometimes behind them. 
The seat of stricture of a femoral hernia varies: it may be in the peritoneum at 
the neck of the hernial sac; in the greater number of cases it •would appear to be at 
the point of junction of the falciform process of the fascia lata with the lunated edge 
of Gimbernat's ligament, or at the margin of the saphenous opening in the thigh. 
The stricture should in every case be divided in a direction upward and inward, and 
the extent necessary in the majority of cases is about two or three lines. By these 
means all vessels or other structures of importance in relation with the neck of the 
hernial sac will be avoided. Surgical Anatomy of the Perineum and Ischio- 
rectal Reo'ion. 
Dissection.-The student should select a well-developed muscular [male] subject free from 
fat, and the dissection should be commenced early, in order that the parts may be examined in 
as recent a state as possible. A staff having been introduced into the bladder, and the subject 
placed in the position shown in Fig. 673, the scrotum should be raised upward and retained in 
that position, and the rectum moderately distended with tow [the anus being closed by stitches]. 
The space which is now exposed corresponds to the inferior aperture or outlet of 
the pelvis. Its deep boundaries are, in front, the pubic arch and subpubic ligament; 
behind, the tip of the coccyx; and on each side, the ramus of the pubes and ischium, 
the tuberosity of the ischium, and great sacro-sciatic ligament. The space included 
by these boundaries is somewhat lozenge-shaped, and is limited on the surface of the 
Fig. 673. 
Dissection of Perineum and Ischio-rectal Region. 
body by the scrotum in front, by the buttocks behind, and on each side by the inner 
side of the thighs. It measures, from before backward, about three and a quarter 
inches, and about three and a half in the broadest part of its transverse diameter, 
between the ischial tuberosities. A line drawn transversely between the anterior 
part of the tuberosity of the ischium on each side in front of the anus divides this 
space into two portions. The anterior portion contains the penis and urethra, and 
is called the perineum. The posterior portion contains the termination of the rec- 
tum, and is called the ischio-rectal region. 
The ischio-rectal region corresponds to the portion of the outlet of the pelvis 
situated immediately behind the perineum: it contains the termination of the rec- 
tum. A deep fossa filled with fat is seen on either side of the intestine between it 
and the tuberosity of the ischium : this is called the ischio-rectal fossa. 
The ischio-rectal region presents in the middle line the aperture of the anus ; 
around this orifice the integument is thrown into numerous folds, which are obliter- 
ated on distension of the intestine. The integument is of a dark color, continuous 
with the mucous membrane of the rectum, and provided with numerous follicles, 
which occasionally inflame and suppurate and may be mistaken for fistulse. The 
veins around the margin of the anus are occasionally much dilated, forming a num- 
IsCHIO-RECTAL REGION. 
1010 ISCHIO-RECTAL REGION. 
1011 
her of hard pendent masses of a dark bluish color, covered partly by mucous mem- 
brane and partly by the integument. These tumors constitute the disease called 
external piles. 
Dissection.-Make an incision through the integument along the median line, from the base 
of the scrotum to the anterior extremity of the anus; carry it round the margins of this aper- 
ture to its posterior extremity, and continue it backward about an inch behind the tip of the 
coccyx. A transverse incision should now be carried across the base of the scrotum at the ante- 
rior extremity of the preceding; a second, carried in the same direction, should be made in front 
of the anus ; and a third at the posterior extremity of the gut. These incisions should be suffi- 
ciently extensive to enable the dissector to raise the integument from the inner side of the thighs. 
The flaps of skin corresponding to the ischio-rectal region (Figs. 673-680) should now be removed. 
In dissecting the integument from this region great care is' required, otherwise the Corrugator 
cutis ani and External sphincter will be removed, as they are intimately adherent to the skin. 
The superficial fascia is exposed on the removal of the skin : it is very thick, 
areolar in texture, and contains much fat in its meshes. In it are found ramifying 
two or three cutaneous branches of the small sciatic nerve; these turn round the 
inferior border of the Gluteus maximus and are distributed to the integument in 
this region. 
Corrug-ator Cutis Ani.-Around the anus is a thin stratum of involuntary 
muscle which radiates from the interior of the anus, where it commences in the 
submucous tissue, to the skin outside, where it blends with the subcutaneous tissue. 
By its contraction it raises the skin into ridges radiating from the margin of the 
anus. 
The External Sphincter is a thin flat plane of muscular fibres, elliptical in 
shape, and intimately adherent to the integument surrounding the margin of the 
anus. It measures about three or four inches in length from its anterior to its pos- 
terior extremity, being about an inch in breadth opposite the anus. It arises from 
the tip of the coccyx by a narrow tendinous band, and from the superficial fascia 
in front of that bone, and is inserted into the tendinous centre of the perineum, 
joining with the Transversus perinsei, the Levator ani, and the Accelerator urinse. 
Like other sphincter muscles, it consists of two planes of muscular fibres, which 
surround the margin of the anus and join in a commissure before and behind. 
Relations.-By its superficial surface with the integument; by its deep sur- 
face it is in contact with the internal Sphincter, and is separated from the Leva- 
tor ani by loose areolar tissue. 
The Sphincter ani is a voluntary muscle supplied by the hemorrhoidal branch 
of the fourth sacral nerve. This muscle is divided in the operation for fistula in 
ano, and also in some cases of fissure of the rectum, especially if attended with 
much pain or spasm. The object of its division is to keep the parts at rest and in 
contact during the healing process. 
The Internal Sphincter is a muscular ring about an inch in breadth which sur- 
rounds the lower extremity of the rectum, its inferior border being contiguous to, 
but quite separate from, the External sphincter. This muscle is about two lines in 
thickness, and is formed by an aggregation of the involuntary circular fibres of 
the intestine. It is paler in color and less coarse in texture than the External 
sphincter. 
The Ischio-rectal Fossa is situated between the end of the rectum and the 
tuberosity of the ischium on each side. It is triangular in shape; its base, 
directed to the surface of the body, is formed by the integument of the ischio- 
rectal region; its apex, directed upward, corresponds to the point of division of the 
obturator fascia and the thin membrane given off from it which covers the outer 
surface of the Levator ani (anal fascia). Its dimensions are about an inch in 
breadth at the base and about two inches in depth, being deeper behind than in 
front. It is bounded internally by the Sphincter ani, Levator ani, and Coccygeus 
muscles; externally by the tuberosity of the ischium and the obturator fascia, 
which covers the inner surface of the Obturator internus muscle; it is lim- 
ited by the line of junction of the superficial and deep perineal fasciae; and behind, 1012 
SURGICAL ANATOMY OF THE PERINEUM. 
by the margin of the Gluteus maximus and the great sacro-sciatic ligament. This 
space is filled with a large mass of adipose tissue, which explains .the frequency 
with which abscesses in the neighborhood of the rectum burrow to a considerable 
depth- 
If the subject has been injected, on placing the finger on the outer wall of this 
fossa the internal pudic artery and its accompanying veins and nerve will be felt 
about an inch and a half above the margin of the ischiatic tuberosity, but approach- 
ing nearer the surface as they pass forward along the inner margin of the pubic 
arch. These structures are enclosed in a sheath formed by the obturator fascia, the 
pudic nerve lying below the artery (Fig. 402, p. 588). Crossing the space trans- 
versely about its centre are the inferior hemorrhoidal vessels and nerves, branches 
of the internal pudic; they are distributed to the integument of the anus and to the 
muscles of the lower end of the rectum. These vessels are occasionally of large 
size, and may give rise to troublesome hemorrhage when divided in the operation 
of lithotomy or of fistula in ano. At the back part of this space may be seen a 
branch of the fourth sacral nerve, and at the fore part of the space a cutaneous 
branch of the perineal nerve. 
Perineum. 
The perineal space is of a triangular form ; its deep boundaries are limited lat- 
erally by the rami of the pubes and ischia, meeting in front at the pubic arch ; 
behind by an imaginary transverse line extending between the tuberosities of the 
ischia. The lateral boundaries are, in the adult, from three inches to three inches 
Fig. 674. 
The Perineum, the Integument and Superficial Layer of Superficial Fascia reflected. 
and a half in length, and the base from two to three inches and a half in breadth, 
the average extent of the space being two inches and three-quarters. The varia- 
tions in the diameter of this space are of extreme interest in connection with the 
operation of lithotomy and the extraction of a stone from the cavity of the bladder. PERINE UM. 
1013 
In those cases where the tuberosities of the ischia are near together it would be 
necessary to make the incisions in the lateral operation of lithotomy less oblique 
than if the tuberosities were widely separated, and the perineal space, consequently, 
wider. The perineum is subdivided by the median raphfi into two equal parts. 
Of these, the left is the one in which the operation of lateral lithotomy is per- 
formed. 
In the middle line the perineum is convex and corresponds to the bulb of the 
urethra. The skin covering it is of a dark color, thin, freely movable upon the 
subjacent parts, and covered with sharp crisp hairs, which should be removed 
before the dissection of the part is commenced. In front of the anus a prominent 
line commences, the raphfi, continuous in front with the raphe of the scrotum. 
The flaps of integument corresponding to this space having been removed in the 
manner shown in Fig. 674, the superficial fascia is exposed. 
Fig. 675. 
.Superficial PerinealArtery 
-Superficial Perineal Nerve 
Internal Pudie Nerve 
-Internal Pitdic Artery 
Grf Sacra-Sciatic Ligt- 
The Superficial Muscles and Vessels of the Perineum. 
Tlie superficial fascia consists of two layers, superficial and deep, as in other 
regions of the body. 
The superficial layer is thick, loose, areolar in texture, and contains much 
adipose tissue in its meshes, the amount of which varies in different subjects. In 
front it is continuous with the dartos of the scrotum ; behind it is continuous with 
the subcutaneous areolar tissue surrounding the anus; and on either side with the 
same fascia on the inner side of the thighs. This layer should be carefully removed 
after it has been examined, when the deep layer will be exposed. 
The deep layer of superficial fascia (superficial perineal fascia) is thin, aponeur- 
otic in structure, and of considerable strength, serving to bind down the muscles 
of the root of the penis. It is continuous in front with the dartos of the scrotum; 
on either side it is firmly attached to the margins of the rami of the pubes and 
ischium, external to the crus penis and as far back as the tuberosity of the ischium > 
posteriorly it curves down behind the Transversus perinsei muscles to join the lower 
margin of the deep perineal fascia. This fascia not only covers the muscles in this 1014 
SURGICAL ANATOMY OF THE PERINEUM. 
region, but sends down a vertical septum from its under surface which separates the 
back part of the subjacent space into two, being incomplete in front. 
In rupture of the anterior portion of the urethra accompanied by extravasation 
of urine the fluid makes its way forward, beneath this fascia, into the areolar tissue 
of the scrotum, penis, and anterior and lateral portions of the abdomen; it rarely 
extends into the areolar tissue on the inner side of the thighs or backward around 
the anus. This limitation of the extravasatecl fluid to the parts above named is 
easy of explanation when the attachments of the deep layer of the superficial fascia 
are considered. When this fascia is removed the muscles connected with the penis 
and urethra will be exposed; these are, in the middle line, the Accelerator urinae, 
on each side the Erector penis, and behind the Transversus perinaei. 
The Accelerator urinae (Ejaculator seminis or bulb o-c aver no sus) is placed in the 
middle line of the perineum, immediately in front of the anus. It consists of two 
symmetrical halves united along the median line by a tendinous raphd. It arises 
from the central tendon of the perineum and from the median raphd in front. 
From this point its fibres diverge like the plumes of a pen; the most posterior form 
a thin layer which is lost on the anterior surface of the triangular ligament; the 
middle fibres encircle the bulb and adjacent parts of the corpus spongiosum, and 
join with the fibres of the opposite side, on the upper part of the corpus spongi- 
osum, in a strong aponeurosis; the anterior fibres, the longest and most distinct, 
spread out over the sides of the corpus cavernosum, to be inserted partly into that 
body anterior to the Erector penis, occasionally extending to the os pubis, partly 
terminating in a tendinous expansion which covers the dorsal vessels of the penis. 
The latter fibres are best seen by dividing the muscle longitudinally and dissecting 
it outward from the surface of the urethra. 
Action.-This muscle serves to empty the canal of the urethra after the bladder 
has expelled its contents ; during the greater part of the act of micturition its fibres 
are relaxed, and it only comes into action at the end of the process. The middle 
fibres are supposed by Krause to assist in the erection of the corpus spongiosum 
by compressing the erectile tissue of the bulb. The anterior fibres, according to 
Tyrrel, also contribute to the erection of the penis, as they are inserted into and 
continuous with the fascia of the penis, compressing the dorsal vein during the 
contraction of the muscle. 
The Erector Penis covers the unattached part of the crus penis. It is an 
elongated muscle, broader in the middle than at either extremity, and situated on 
either side of the lateral boundary of the perineum. It arises by tendinous and 
fleshy fibres from the inner surface of the tuberosity of the ischium, behind the 
crus penis, from the surface of the crus and from the adjacent portion of the ramus 
of the pubes. From these points fleshy fibres succeed, ending in an aponeurosis 
which is inserted into the sides and under surface of the crus penis. This muscle 
compresses the crus penis and retards the return of the blood through the veins, 
and thus serves to maintain the organ erect. 
The Transversus Perinaei is a narrow muscular slip which passes more or less 
transversely across the back part of the perineal space. It arises by a small tendon 
from the inner and fore side of the tuberosity of the ischium, and, passing obliquely 
forward and inward, is inserted into the central tendinous point of the perineum, 
joining in this situation with the muscle of the opposite side, the Sphincter ani 
behind, and the Accelerator urinae in front. 
Between the muscles just examined a triangular space exists, bounded internally 
by the Accelerator urinae, externally by the Erector penis, and behind by the Trans- 
versus perinaei. The floor of this space is formed by the triangular ligament of the 
urethra (deep perineal fascia), and running from behind forward in it are the super- 
ficial perineal vessels and nerves, the transverse perineal artery coursing along the 
posterior boundary of the space on the Transversus perinaei muscle. 
In the lateral operation of lithotomy the knife is carried obliquely across the 
back part of this space downward and outward into the ischio-rectal fossa, dividing 
the Transversus perinaei muscle and artery, the posterior fibres of the Acclerator PERINEUM. 
1015 
urinae, the superficial perineal vessels and nerve, and more posteriorly the inferior 
hemorrhoidal vessels. 
The superficial and transverse perineal arteries are described at p. 589, and the 
superficial perineal and inferior pudendal nerves at pp. 778 and 780. 
The muscles of the perineum in the female are the- 
Sphincter vaginae (Bulbo-cavernosus). 
Erector clitoridis. 
Transversus perinaei. 
Sphincter ani. 
Levator ani. 
Coccygeus. 
Superficial Muscles. 
Deep Transversus perinaei. 
Constrictor vaginae. 
Depressor urethrae (Jarjavay's muscle).] 
\Deep Muscles. . . . 
The Sphincter Vaginae or Bulbo-cavemosus is placed on each side of the 
orifice of the vagina, and is analogous to the Accelerator urinse in the male. It is 
attached posteriorly to the cen- 
tral tendon of the perineum, 
where it blends with the Sphinc- 
ter ani. Its fibres pass forward 
on each side of the vagina to 
be inserted into the corpora 
cavernosa of the clitoris, a fas- 
ciculus crossing over the body 
of the organ so as to compress 
the dorsal vein. 
The Erector Clitoridis re- 
sembles the Erector penis in 
the male, but is smaller than it, 
arising from the tuberosity of 
the ischium and being inserted 
on each side of the crus. 
The Trans versus Perinaei 
is inserted into the side of the 
Sphincter vaginae, and the Lev- 
ator ani into the side of the 
vagina and rectum. The other 
muscles are precisely similar to 
those in the male. 
[The Deep Transversus 
Perinaei arises from the ramus 
of the ischium, and passes to the central point of the perineum. 
The Constrictor Vaginae consists of a few fibres which arise from the central 
tendon of the perineum and encircle the vaginal opening. It is joined by 
The Depressor Urethrae (Jarjavay's muscle), which arises from the ramus of 
the ischium close to the deep Transverse muscle, and sometimes united with it. It 
runs upward and inward to join the fibres of the Constrictor, and also to join its 
fellow-muscle over the urethra. 
The student will have great difficulty in dissecting these deep muscles, even in 
favorable subjects and when dissected early. But every student should dissect care- 
fully the perineum in the female, as well as the male, in order at least to get a cor- 
rect general idea of its anatomy.] 
The Accelerator urinae and Erector penis muscles should now be removed, when the deep peri- 
neal fascia will be exposed, stretching across the front part of the outlet of the pelvis. The 
urethra is seen perforating its centre just behind the bulb, and on either side is the crus penis, 
connecting the corpus cavernosum with the ramus of the ischium and pubes. 
The deep perineal fascia (triangular ligament [Figs. 679, 681, 682]) is a dense 
membranous lamina which closes the front part of the outlet of the pelvis. It is 
[Fig. 676. 
The Muscles of the Female Perineum, superficial on right, and 
deep on left side: 1, clitoris; 2, Erector clitoridis; 3, Jarjavay's 
muscle (Depressor urethrae); 4, bulb of vagina; 5, Transversus 
perinaei (reflected); 6, Bulbo-cavernosus (Sphincter vaginae); 
7, Constrictor vaginae; 8, gland of Bartholin; 9, Deep Transversus 
perinaei; 10, Superficial Transversus perinaei;. 11, posterior layer 
of triangular ligament; 12, Sphincter ani; 13, triangular liga- 
ment ; 14, Levator ani; 15, ischio-perineal ligament (Savage and 
Luschka).] 1016 
SURGICAL ANATOMY OF THE PERINEUM. 
triangular in shape, about an inch and a half in depth, attached above, by its apex, 
to the under surface of the symphysis pubis and subpubic ligament, and on each 
side to the rami of the ischium and pubes beneath the crura penis. Its inferior 
margin, or base, is directed toward the rectum and connected to the central tendin- 
ous point of the perineum. It is continuous with the deep layer of the superficial 
[Fig. 677. 
1, Pudic artery. 
2, Branch to Levator ani. 
3, Inferior hemorrhoidal artery. 
4, Transverse artery. 
5, Great labial (superficial perineal) artery. 
7, Dorsal artery of clitoris. 
8, Artery of bulb. 
9, Artery to crus clitoridis. 
10, Inferior hemorrhoidal nerve. 
11, Pudic nerve. 
12, Muscular branch. 
13, Internal superficial perineal nerve. 
14, External superficial perineal nerve. 
15, Its junction with- 
16, Inferior pudendal nerve. 
17, Small sciatic nerve. 
18,18, Dorsal nerve of clitoris. 
The Female Perineum. 
19, Ilio-inguinal nerve. 
A, Anus. 
C, Clitoris. 
M, Meatus urinarius. 
L, Great sacro-sciatic ligament. 
V, Vagina. 
0, Coccyx. 
T, Tuberosity of ischium. 
a, Gluteus maximus. 
c, Levator aui. 
d, Superficial transverse muscle. 
e, Compressor bulbi. 
g, Erector clitoridis. 
h, Triangular ligament (cut). 
i, Biceps and Semitendinosus. 
j, Adductor magnus. 
k, Gracilis (Dr. Savage's Illustrations).] 
fascia behind the Transversus perinaei muscle, and with a thin fascia which covers 
the cutaneous surface of the Levator ani muscle (anal fascia). 
The triangular ligament in the female is not so strong as in the male. It is 
attached to the pubic arch, its apex being connected with the symphysis pubis. It 
is divided in the middle line by the aperture of the vagina, with the external coat 
of which it becomes blended, and in front of this is perforated by the urethra. Its 
posterior border is continuous, as in the male, with the deep layer of the superficial 
fascia around the Transversus perinaei muscle. 
The deep perineal fascia is perforated by the urethra about an inch below the 
symphysis pubis. The aperture is circular in form and about three or four lines in 
diameter. Above this is the aperture for the dorsal vein of the penis, and outside 
the latter the pudic nerve and artery pierce it. 
The deep perineal fascia consists of two layers, anterior and posterior; these are 
separated above, but united below. 
The anterior layer is continued forward around the anterior part of the mem- 
branous portion of the urethra, becoming lost upon the bulb. 
The posterior layer is derived from the obturator fascia;1 it is continued back- 
ward around the posterior part of the membranous portion of the urethra and the 
outer surface of the prostate gland. 
1 " On the Anatomy of the Posterior Layer of the Triangular Ligament," see a paper by Mr. 
Carrington, in Guy's Hospital Reports. PERINE UM. 
1017 
If the anterior layer of this fascia is detached on either side, the following parts 
are seen between it and the posterior layer: The subpubic ligament above, close to 
the pubes, the dorsal vein of the 
penis, the membranous portion of 
the urethra, and the Compressor 
urethrae muscle; Cowper's glands 
and their ducts; the pudic vessels 
and dorsal nerve of the penis; the 
artery and nerve of the bulb ; and 
a plexus of veins. 
The CompressorUrethrse 
strictor urethrce [Guthrie's muscle, 
Fig. 678, 8, 9]) surrounds the whole 
length of the membranous portion 
of the urethra, and is contained be- 
tween the two layers of the deep 
perineal fascia. It arises by apo- 
neurotic fibres from the upper part 
of the ramus of the pubes on each 
side to the extent of half or three- 
quarters of an inch: each segment 
of the muscle passes inward and di- 
vides into two fasciculi, which sur- 
round the urethra from the prostate 
gland behind to the bulbous portion 
of the urethra in front, and unite at 
the upper and lower surfaces of this 
tube with the muscle of the opposite 
side by means of a tendinous raphd. 
[The perpendicular portion, gener- 
ally called Wilson's muscle (Fig. 678, 10), is now usually discarded by anatomists.] 
Circular muscular fibres surround the membranous portion of the urethra from 
the bulb in front to the prostate gland behind ; they are placed immediately beneath 
the transverse fibres already described, and are continuous with the muscular fibres 
of the bladder. These fibres are involuntary. 
Cowper s Glands are situated immediately below the membranous portion of the 
urethra, close behind the bulb and below the artery of the bulb. 
The Pudic Vessels and Dorsal Nerve of the Penis are placed along the inner 
margin of the pubic arch (pp. 588 and 778). 
The Artery of the Bulb passes transversely inward from the internal pudic along 
the base of the triangular ligament, between the two layers of fascia, accompanied 
by a branch of the pudic nerve (p. 589). 
If the posterior layer of the deep perineal fascia is removed and the crus penis 
of one side detached from the bone, the under or perineal surface of the Levator 
ani is brought fully into view. This muscle, with the triangular ligament in front 
and the Coccygeus and Pyriformis behind, closes in the outlet of the pelvis. 
The Levator ani is a broad thin muscle situated on each side of the pelvis. It 
is attached to the inner surface of the sides of the true pelvis, and, descending, unites 
with its fellow of the opposite side to form the floor of the pelvic cavity. It supports 
the viscera in this cavity and surrounds the various structures which pass through it. 
It arises in front from the posterior surface of the body and ramus of the pubes on 
the outer side of the symphysis; posteriorly from the inner surface of the spine of 
the ischium; and between these two points from the angle of division between the 
obturator and recto-vesical layers of the pelvic fascia at their under part [Fig. 681, 
p. 1020]: the fibres pass downward to the middle line of the floor of the pelvis, and 
are inserted, the most posterior fibres into the sides of the apex of the coccyx; those 
placed more anteriorly unite with the muscle of the opposite side in a median fibrous 
[Fig. 678. 
Tbe Structures contained between tbe two Layers of the Deep 
Perineal Fascia : 1, the symphysis pubis; 2, 2, the ramus of 
the pubes and ischium ; 3, 3, the tuberosities of the ischia; 
4, a triangular portion of the superficial fascia turned down 
and shown to be continuous with the deep fascia (6); 5, 5, 
two portions of the superficial perineal fascia, showing its 
connection to the ramus of the pubes and ischium ; 6, 6, the 
posterior layer of the deep perineal fascia, the anterior layer 
having been removed; 7, the membranous portion of the 
urethra cut across; 8, the superior fasciculus of the Com- 
pressor urethrae muscle of one side; 9, the inferior fascicu- 
lus of the Compressor urethra. The two fasciculi (8 and 9) 
constitute Guthrie's muscle of one side; 10, the pubic por- 
tions of the Compressor urethra, Wilson's muscles; 11, Cow- 
per's glands, partly embraced by the lower fasciculus of the 
Compressor urethra muscle; 12, the internal pudic artery, 
passing posteriorly to tbe crus of the Compressor urethra; 
13, the artery of the bulb; 14, the artery of the corpus caver- 
nosum; 15, the arteria dorsalis penis (Wilson).] 1018 
SURGICAL ANATOMY OF THE PERINEUM. 
raphe which extends between the coccyx and the margin of the anus. The middle 
fibres, which form the larger portion of the muscle, are inserted into the side of the 
rectum, blending with the fibres of the Sphincter muscles; lastly, the anterior fibres, 
the longest, descend upon the side of the prostate gland to unite beneath it with the 
muscle of the opposite side, blending with the fibres of the External sphincter and 
Transversus perinaei muscles at the tendinous centre of the perineum. 
The anterior portion is occasionally separated from the rest of the muscle by 
areolar tissue. From this circumstance, as well as from its peculiar relation with 
Fig. 679. 
Anter io r Layer of 
Deep. Perinea# Pascia remcvocl 
Shewing 
COMPRESSOR URETHRA 
Jnitmal Pudic Art1/. 
-Arty of the Btclb 
- Coivjier's Gia nd 
Deep Perineal Fascia; on the left side the anterior layer has been removed. 
the prostate gland, descending by its side and surrounding it as in a sling, it has 
been described by Santorini and others as a distinct muscle under the name of the 
Levator prostatce. In the female the anterior fibres of the Levator ani descend 
upon the sides of the vagina. 
Relations [Fig. 681].-By its inner or pelvic surface with the recto-vesical 
fascia, which separates it from the viscera of the pelvis and from the peritoneum. 
By its older or perineal surface it forms the inner boundary of the ischio-rectal 
fossa, and is covered by a quantity of fat and by a thin layer of fascia (anal fascia) 
continued from the obturator fascia. Its posterior border is continuous with the 
Coccygeus muscle. Its anterior border is separated from the muscle of the opposite 
side by a triangular space through which the urethra, and in the female the vagina, 
passes from the pelvis. 
Actions.-This muscle supports the lower end of the rectum and vagina, and 
also the bladder, during the efforts of expulsion. It elevates and inverts the lower 
end of the rectum, after it has been protruded and everted during the expulsion of 
the feces. It is also a muscle of forced expiration. 
The Coccyg-eus is situated behind and parallel with the preceding. It is a tri- 
angular plane of muscular and tendinous fibres, arising by its apex from the spine 
of the ischium and lesser sacro-sciatic ligament, and inserted by its base into the 
margin of the coccyx and into the side of the lower piece of the sacrum. This 
muscle is continuous with the posterior border of the Levator ani and closes in the 
back part of the outlet of the pelvis. PERINE UM. 
1019 
Relations.-By its inner or pelvic surface with the rectum ; by its external sur- 
face with the lesser sacro-sciatic ligament; by its posterior border with the Pyriformis. 
Action.-The Coccygei muscles raise and support the coccyx after it has been 
pressed backward during defecation or parturition. 
Position of the Viscera at the Outlet of the Pelvis.-Divide the central tendinous point of the 
perineum, separate the rectum from its connections by dividing the fibres of the Levator ani, 
which descend upon the sides of the prostate gland, and draw the gut backward toward the 
coccyx, when the under surface of the prostate gland, the neck and base of the bladder, the 
vesiculae seminales, and vasa deferentia will be exposed. 
The Prostate Gland is placed immediately in front of the neck of the bladder 
around the prostatic portion of the urethra, its base being turned backward and 
its under surface toward the rectum. It is retained in its position by the Levator 
prostatm and by the pubo-prostatic ligaments, and is invested by a dense fibrous 
covering continued from the posterior layer of the deep perineal fascia. The long- 
est diameters of this gland are in the antero-posterior direction and transversely at 
its base; and hence the greatest extent of incision that can be made in it without 
dividing its substance completely across is obliquely outward and backward. This 
is the direction in which the incision is made through it in the operation of [lateral] 
lithotomy, the extent of which should seldom exceed an inch in length. The rela- 
tions of the prostate to the rectum should be noticed: by means of the finger intro- 
duced into the gut the surgeon detects enlargement or other disease of this organ; 
Fig. 680. 
Artery of Corpus Cavernosum. 
Dorsal- Artery of Penis 
Artery of Pull 
internal Pndic Artery 
Cowper's Gland 
A View of the Position of the Viscera at the Outlet of the Pelvis. 
he is enabled also by the same means to direct the point of a catheter when its 
introduction is attended with much difficulty either from injury or disease of the 
membranous or prostatic portions of the urethra. 
Behind the prostate is the posterior surface of the neck and base of the bladder: 
a small triangular portion of this organ is seen, bounded in front by the prostate 
gland, behind by the recto-vesical fold of the peritoneum, on each side by the vesic- 
ulse seminales and vasa deferentia, and separated from direct contact with the rec- 
tum by the recto-vesical fascia. The relation of this portion of the bladder to the 1020 
SURGICAL ANATOMY OF THE PERINEUM. 
rectum is of extreme interest to the surgeon. In cases of retention of urine this 
portion of the organ is found projecting into the rectum between three and four 
inches from the margin of the anus, and may be easily perforated during life with- 
out injury to any important parts; this portion of the bladder is consequently fre- 
quently selected for the performance of the operation of tapping the bladder. If 
the finger be introduced into the bowel, the surgeon may in some cases learn the 
position as well as the size and weight of a calculus in the bladder; and in the 
operation for its removal, if, as is not unfrequently the case, it should be lodged 
behind an enlarged prostate, it may be displaced from its position by pressing 
upward the base of the bladder from the rectum. 
Parts Concerned in the Operation of Lithotomy.-The triangular ligament 
must be replaced and the rectum drawn forward so as to occupy its normal position. 
Fig. 681. 
-Iliac .Fascia 
A nterior Cr ur al.Nerve- 
External Iliac Vessels'. 
r Brun of Pei-vls i 
yj'rtvtrFas.l 
Obturator Fascia, - 
Internal Pudic Vessels k. Nerve- 
A Transverse Section of the Pelvis, showing the pelvic fascia from behind. 
The student should then consider the position of the various parts in reference to 
the lateral operation of lithotomy. This operation is performed on the left side of 
the perineum, as it is most convenient for the right hand of the operator. A staff 
having been introduced into the bladder, the first incision is commenced midway 
between the anus and the back of the scrotum (z. e. in an ordinary adult perineum 
about an inch and a half in front of the anus), a little on the left side of the raph£, 
and carried obliquely backward and outward to midway between the anus and tuber- 
osity of the ischium. The incision divides the integument and superficial fascia, the 
inferior hemorrhoidal vessels and nerves, and the superficial and transverse perineal 
vessels; if the forefinger of the left hand is thrust upward and forward into the 
wound, pressing at the same time the rectum inward and backward, the staff may 
be felt in the membranous portion of the urethra. The finger is fixed upon the 
staff, and the structures covering it are divided with the point of the knife, which 
must be directed along the groove toward the bladder, the edge of the knife being 
turned outward and backward, dividing in its course the membranous portion of the 
urethra and part of the left lobe of the prostate gland to the extent of about an inch. 
The knife is then withdrawn and the forefinger of the left hand passed along the 
staff into the bladder: the staff having been withdrawn and the position of the 
stone ascertained, the forceps is introduced over the finger into the bladder. If PELVIC FASCIA. 
1021 
the stone is very large, the opposite side of the prostate may be notched before the 
forceps are introduced: the finger is now withdrawn, and the blades of the forceps 
opened and made to grasp the stone, which must be extracted by slow and cautious 
undulating movements. 
Parts Divided in the Operation.-The various structures divided in this opera- 
tion are as follows: The integument, superficial fascia, inferior hemorrhoidal vessels 
and nerves, the posterior fibres of the Accelerator urinae, the Transversus perinsei 
muscle and artery (and, probably, the superficial perineal vessels and nerve), the 
deep perineal fascia, the anterior fibres of the Levator ani, part of the Compressor 
urethrae, the membranous and prostatic portions of the urethra, and part of the 
prostate gland. 
Parts to be Avoided in the Operation.-In making the necessary incisions in the 
perineum for the extraction of a calculus the following parts should be avoided: 
The primary incision should not be made too near the middle line, for fear of 
wounding the bulb of the corpus spongiosum or the rectum; nor too far externally, 
otherwise the pudic artery may be implicated as it ascends along the inner border 
of the pubic arch. If the incisions are carried too far forward, the artery of the 
bulb may be divided; if carried too far backward, the entire breadth of the pros- 
tate and neck of the bladder may be cut through, which allows the urine to become 
infiltrated behind the pelvic fascia into the loose areolar tissue between the bladder 
and rectum, instead of escaping externally; diffuse inflammation is consequently 
set up, and peritonitis, from the close proximity of the recto-vesical peritoneal fold, 
is the consequence. If, on the contrary, the prostate is divided in front of the base 
of the gland, the urine makes its way externally, and there is less danger of infiltra- 
tion taking place. 
During the operation it is of great importance that the finger should be passed 
into the bladder before the staff is removed; if this is neglected and if the incision 
made through the prostate and neck of the bladder is too small, great difficulty may 
be experienced in introducing the finger afterward ; and in the child, where the con- 
nections of the bladder to the surrounding parts are very loose, the force made in 
the attempt is sufficient to displace the bladder up into the abdomen out of the reach 
of the operator. Such a proceeding has not unfrequently occurred, producing the 
most embarrassing results and total failure of the operation. 
It is necessary to bear in mind that the arteries in the perineum occasionally 
take an abnormal course. Thus the artery of the bulb, when it arises, as some- 
times happens, from the pudic opposite the tuber ischii, is liable to be wounded in 
the operation for lithotomy in its passage forward to the bulb. The accessory pudic 
may be divided near the posterior border of the prostate gland if this is completely 
cut across, and the prostatic veins, especially in people advanced in life, are of large 
size, and give rise, when divided, to troublesome hemorrhage. 
Pelvic Fascia. 
The Pelvic Fascia (Fig. 682) is a thin membrane which lines the whole of the 
cavity of the pelvis and is continuous with the transversalis and iliac fasciaa. It is 
attached to the brim of the pelvis for a short distance at the side of the cavity, and 
to the inner surface of the bone round the attachment of the Obturator interims. 
At the posterior border of this muscle it is continued backward as a very thin mem- 
brane in front of the Pyriformis muscle and sacral nerves, behind the branches of 
the internal iliac artery and vein (which perforate it), to the front of the sacrum. 
In front it follows the attachment of the Obturator internus to the bone, arches 
beneath the obturator vessels, completing the orifice of the obturator canal, and at 
the front of the pelvis is attached to the lower part of the symphysis pubis. At the 
level of a line extending from the lower part of the symphysis pubis to the spine of 
the ischium is a thickened whitish band; this marks the attachment of the Levator 
ani muscle to the pelvic fascia, and corresponds to its point of division into two 
layers, the obturator and recto-vesical. 1022 
SURGICAL ANATOMY OF THE PERINEUM. 
The obturator fascia descends and covers the Obturator internus muscle. It 
is a direct continuation of the pelvic fascia below the white line above mentioned, 
and is attached to the pubic arch and to the margin of the great sacro-sciatic liga- 
Fig. 682. 
dlladde r 
CfhvpiTS (Hand 
Side View of the Pelvic Viscera of the Male Subject, showing the pelvic and perineal fasciae. [Compare with 
Fig. 639, p. 956.] 
ment. From its attachment to the pubes a process is given off which is continuous 
with a similar process from the opposite side, so as to close the front part of the out- 
let of the pelvis, forming the posterior layer of the triangular ligament. This fascia 
forms a canal for the pudic vessels and nerve in their passage forward to the peri- 
neum, and is continuous with a thin membrane which covers the perineal aspect of 
the Levator ani muscle, called the ischio-rectal (anal) fascia. 
The recto-vesical fascia (visceral layer of the pelvic fascia) descends into the 
pelvis upon the upper surface of the Levator ani muscle, and invests the prostate, 
bladder, and rectum. From the inner surface of the symphysis pubis a short 
rounded band is continued to the upper surface of the prostate and neck of the 
bladder, forming the pubo-prostatic or anterior true ligaments of the bladder. At 
the side this fascia is connected to the side of the prostate, enclosing this gland and 
the vesico-prostatic plexus of veins, and is continued upward on the surface of the 
bladder, forming the lateral true ligaments of the organ. Another prolongation 
invests the vesiculae seminales and passes across between the bladder and rectum, 
being continuous with the same fascia of the opposite side. Another thin prolon- 
gation is reflected round the surface of the lower end of the rectum. The Levator 
ani muscle arises from the point of division of the pelvic fascia, the visceral layer 
of the fascia descending upon and being intimately adherent to the upper surface 
of the muscle, while the under surface of the muscle is covered by a thin layer 
derived from the obturator fascia, called the ischio-rectal or anal fascia. In the 
female the vagina perforates the recto-vesical fascia and receives a prolongation 
from it. LANDMARKS, 
MEDICAL AND SURGICAL. 
BY 
LUTHER HOLDEN, 
EX-PRESIDENT, MEMBER OF COUNCIL, AND MEMBER OF THE COURT OF EXAMINERS OF THE ROYAL 
COLLEGE OF SURGEONS OF ENGLAND ; CONSULTING SURGEON TO SAINT BARTHOLOMEW'S 
AND THE FOUNDLING HOSPITALS ; 
ASSISTED BY 
JAMES SHUTER, M.A. Camb., E.R.C.S., 
ASSISTANT SURGEON TO THE ROYAL FREE HOSPITAL ; LATE DEMONSTRATOR OF PHYSIOLOGY, ARD 
LATE ASSISTANT DEMONSTRATOR OF ANATOMY, AT SAINT BARTHOLOMEW'S HOSPITAL. 
FROM THE THIRD ENGLISH EDITION, WITH ADDITIONS, 
BY 
WILLIAM W. KEEN, M.D., 
Professor of Surgery in the Woman's Medical College of Pennsylvania; Professor of Artistic 
Anatomy in the Pennsylvania Academy of the Fine Arts; formerly Lecturer on 
Anatomy in the Philadelphia School of Anatomy; Surgeon to St. Mary's 
Hospital ; Fellow of the College of Physicians of Philadelphia, etc. 
1887. 
" Chirurgus mente prius et oculis agat quam manu armat&s' LANDMARKS, 
MEDICAL AND SURGICAL. 
[See on p. 33 of Gray's Anatomy (edition of 1887) the introductory paper, by W. W. Keen, M. D., 
the American editor, " On the Systematic Use of the Living Model in Teaching Anatomy.''] 
1. In clinical teaching we often have occasion to point out, on the surface of the 
living body, what may be called "medical and surgical landmarks." By "landmarks" 
we mean surface-marks, such as lines, eminences, depressions, which are guides to, or 
indications of, deeper-seated parts. This practice is not only most useful, but absolutely 
necessary, because many even advanced students of anatomy are not so ready as they 
ought to be in their recognition of parts when covered by skin. Students who may 
be familiar enough with bones, muscles, blood-vessels, or viscera in the dissected sub- 
ject are often sadly at fault when they come to put this knowledge into practice in the 
living. 
For instance, ask a student to put his finger on the exact place where he would feel 
for the head of the radius, the coracoid process of the scapula, the tubercle of the sca- 
phoid bone in the foot; ask him to compress effectually one of the main arteries, to chalk 
the line of its course; to map on the chest the position of the heart and the several 
valves at its base; to trace along the walls of the chest the outline of the lungs and 
pleura; to point out the bony prominences about the joints, and their relative position in 
the different motions of the joints; test him about the muscles and tendons which can 
be seen or felt as they stand out in relief or remain in repose; let him introduce his 
finger into the several orifices of the body and say what parts are accessible to the 
touch,-questions such as these even a good anatomist, unaccustomed to deal with the 
living subject, might possibly find himself at a loss to answer. 
2. Object in View.-Our main object, therefore, is to induce in students the habit 
of looking at the living body with anatomical eyes, and with eyes, too, at their fingers' 
ends. The value of this habit cannot be too highly estimated. Is it not of the utmost 
importance to an operating surgeon that he should have in his mind's eye the various 
structures of the body as they lie grouped, connected, and working together? Should 
he not try at least to see them with the same clearness and accuracy as if they were 
perfectly transparent ? 
Moreover, the habit of examining the living body with " anatomical eyes " and " sur- 
gical fingers " teaches the eye and the hand to act together, and trains that delicate sense 
of touch which every surgeon should possess. 
This habit is within easy reach of any one who has carefully dissected for himself 
and learned what to feel for. Plates will not give him this knowledge. Let a student 
examine his own body with a skeleton before him. Better still that two should work 
thus together, each serving as a model to the other. 
Teachers of anatomy should follow the example of Sir C. Bell, who was in the habit 
of introducing, from time to time, a powerful muscular fellow to his class, " in order to 
show how much of the structure of the body, such as the articulations and the muscles, 
might be learned without actual dissection."1 
At the same time, it is only fair to say that " landmarks " cannot always be defined 
with precision. A considerable latitude must be allowed for natural variations in differ- 
ent persons. In some their anatomy stands out beautifully clear; in others it is masked 
by obesity. Selecting, therefore, for study a moderately lean person, let us begin with 
the head. 
1 Some pertinent remarks on this subject have been made by Mr. C. Heath in a pamphlet On 
Anatomy in Relation to Physic. 
1025 1026 
LANDMARKS. 
THE HEAD. 
3. Scalp : its Density.-The great toughness of the scalp, more especially at the 
back of the head, is owing to its intimate connection with the cranial aponeurosis, the 
scalp-vessels and hair-bulbs intervening. This density often obscures the diagnosis of 
tumors on the cranium. A tumor growing upon the head may be either above or below 
the aponeurosis of the scalp. If below, it will have a firm resisting feel, being bound 
down by the aponeurosis. Nevertheless, its firmness and resistance may depend not 
simply on its confinement beneath the aponeurosis, but on its having its origin [from the 
skull or] within the skull. Look with suspicion, then, on every tumor on the head that 
will not readily permit you to move it about, so as to be sure of its connections prior to 
an attempt at extirpation. 
The scalp moves freely over the pericranium, to which it is very loosely connected by 
areolar tissue. When suppuration takes place in this tissue, free incisions through the 
dense scalp must be made to let the pus out. 
4. Arteries of Scalp.--The supraorbital artery can be felt beating just above the 
supraorbital notch, and traced for some way up to the forehead ; the temporal (anterior 
branch) ascends tortuously about one inch and a quarter behind the external angular 
process of the frontal bone; the occipital can be felt near the middle of a line drawn 
from the occipital protuberance to the mastoid process; the posterior auricular, near the 
apex of the mastoid process. All these arteries can be effectually compressed against 
the subjacent bone. 
5. Skull-cap.-The skull-cap is rarely quite symmetrical. This want of symmetry 
is often obvious. It may occur in men highly gifted, as in the celebrated French anat- 
omist Bichat. As to shape and relative dimensions, no two heads are exactly alike, any 
more than are two faces. It is beside my present purpose to go into the question of 
craniology, more than to say that, although the cranium does not exactly follow the 
brain in all its eminences and depressions so as to be like a cast of its surface, yet it cer- 
tainly indicates the dimensions of the great cerebral masses. The prominence of the 
frontal and parietal " eminences " and of the occipital region may be taken as a gen- 
eral indication of the development of the corresponding lobes of the brain. To ascer- 
tain the relative proportions of these three regions, let a thread be passed from one 
meatus auditorius to the other, across the frontal, parietal, and occipital eminences 
respectively. 
[Anterior Fontanelle.-At the junction of the sagittal and the coronal sutures 
in the new-born child is the anterior fontanelle, caused by the as yet incomplete ossifica- 
tion of the frontal and the parietal bones. It closes at about twelve to eighteen months 
of age. Its condition, as to whether it is a hollow or a hill, is important, for it shows 
the wasting of the fluids of the body, as in the summer diarrhoeas of children, or the 
redundancy of fluid within the skull, as in hydrocephalus. The pulse of a sleeping 
child can often be counted at the fontanelle by the eye alone. In the adult the bregma, 
or point of junction of the sagittal and coronal sutures, is situated, as I have determined 
on 185 skulls, .375 of an inch in front of the line joining the two external auditory 
meatuses. In 16 of these skulls it was on the line, and in 7 behind it.] 
Frontal Sinuses.-The frontal sinuses formed by the separation of the two tables 
of the skull vary much in size in different persons and at different periods of life. This 
fact has an important bearing on wounds in the forehead and on trephining in this situa- 
tion. These " bumps " do not exist in children, because the tables of the skull do not 
begin to separate before puberty. From an examination of many skulls in the Hun- 
terian Museum, I find that the absence of the "bumps," even in middle age, does not 
necessarily imply the absence of the sinuses, since they may be formed by a retrocession 
of the inner wall of the skull. In old persons, as a rule, when the sinuses enlarge it is 
by the encroachment of the inner table on the brain-case. The inner wall of the skull 
here follows the shrinking brain. It is therefore important to bear in mind that an adult, 
and more especially an elderly person, may have a large frontal sinus without any exter- 
nal indication of it. 
Neither does a very prominent bump necessarily imply the existence of a large sinus, 
or indeed of even a small one. The " bump " may be a mere heaping up of bone, a 
degradation, as in some Australian skulls. 
Mastoid Process.-The mastoid process, which can be felt behind the ear, con- 
tains air-cells, to which the above observations may also be applied. [" Mastoid disease," 
or suppuration in these cells, which, like the frontal sinuses, are lined by mucous mem= THE FA CE. 
1027 
brane, causes pain, tenderness, and swelling over the process, and almost always demands 
early trephining to evacuate the pus.] 
Occipital Protuberance.-The occipital protuberance and the superior curved 
line can be distinctly felt at the back of the head. The protuberance is always the 
thickest part of the skull-cap, and more prominent in some than in others. 
The posterior inferior angle of the parietal bone, grooved by the lateral 
sinus, is on a level with the zygoma, and a trifle more than one inch behind the front 
border of the mastoid process. 
Lines of Cerebral Sinuses.-A line drawn over the head from the root of the 
nose to the occipital protuberance corresponds with the superior longitudinal sinus. [As 
the. left hemisphere is the larger of the two, the sinus lies mostly to the right of the 
middle line, the right border of the sinus being indicated by a line at the extremity of 
the dentations of the sagittal suture.] Another line drawn from the occipital protuber- 
ance to the front border of the mastoid process corresponds with a part of the lateral 
sinus. 
Middle Meningeal Artery.-The trunk of the middle meningeal artery runs 
along the front lower corner of the parietal bone, about one inch and a half behind and 
half an inch above the external angular process of the frontal [or one inch and a half 
above the zygoma: this is a more definite measuring-point vertically]. 
A straight line drawn from the front of one mastoid process to the other would pass 
through the middle of the condyles of the occiput, showing how nearly the skull is 
balanced on the top of the spine in the erect posture. 
6. Thickness of Skull-cap.-The average thickness of the cap of an adult skull 
is about I of an inch. The thickest part is at the occipital protuberance, where it is 
often of an inch or more, even in an otherwise thin skull. The thinnest part is at the 
temple, where it may be almost as thin as parchment. Every one in the habit of making 
post-mortem examinations knows how much the skull-cap differs in thickness in different 
persons and in different parts of same skull. In old persons it is often in some parts not 
thicker than a shilling, owing to absorption of the diploe. Another point of interest is 
that the inner plane of the cap is not always parallel with the outer. Hence, in apply- 
ing the trephine this is not a bad rule: " Think that you are operating on the thinnest 
skull ever seen, and thinner in one half of the circle than the other." 
7. Levels of the Brain.-The level of the anterior lobes in front corresponds with 
a straight line drawn across the forehead just above the eyebrows. The lower level of 
the anterior and middle lobes of the cerebrum corresponds with a line drawn from the 
external angular process of the frontal bone to the upper part of the meatus auditorius. 
Another line drawn from the meatus to the occipital protuberance corresponds with the 
lower level of the posterior lobe. The lower level of the cerebellum cannot be defined 
by external examination. It depends upon the extent to which the occipital fossae bulge 
into the nape of the neck; and this bulge varies in different skulls. 
[Ear.-The axis of the auditory canal is not directly transverse, but inward and for- 
ward, toward the opposite temple-a fact of importance in the use of instruments or of 
injections into the ear. The canal should always be inspected with care for abscesses, 
foreign bodies, or impacted wax, and, in cases of possible fracture at the base of the 
skull, for the escape of cerebro-spinal fluid. About one inch from the external meatus 
the canal is closed by the membrana tympani. This can be seen best through a speculum 
by reflected light from a hand or forehead mirror, but not uncommonly it can be seen 
without the speculum. To examine the auditory canal or the membrana tympani the 
auricle must be pulled gently, but decidedly, upward and backward.], 
[Cerebral Localization and. Topography.-(See Gray's Anatomy, p. 681).] 
THE FACE. 
8. The approaches to the organs of the senses, their ever-varying expression, their 
numerous muscles, and their rich profusion of vessels and nerves, give the face great 
anatomical importance, which has a most valuable bearing, not only on the practice of 
surgery, but on the physiognomy of health and in the diagnosis of disease. 
9. Foramina for Branches of Fifth Nerve.-As a surgeon may be called upon 
to divide any one of the three chief branches of the fifth nerve upon the face, he looks 
with interest to the precise situations where they leave their bony foramina with their 
corresponding arteries. The supraorbital notch or foramen can be felt about the junc- 1028 
LANDMARKS. 
tion of the inner with the middle third of the supraorbital margin. From this point a 
perpendicular line drawn with a slight inclination outward, so as to cross the interval 
between the two bicuspid teeth in both jaws, passes over the infraorbital and the mental 
foramina. The direction of these two lower foramina looks toward the angle of the nose. 
[The canal in the lower jaw for the inferior dental nerve, it must be remembered, in per- 
sons who have lost the alveolar process by absorption, lies by so much nearer the upper 
margin of the jaw. A trephine must, therefore, in such persons be applied well above 
the middle of the bone, or the canal may be missed entirely.] 
10. Pulley for Superior Oblique Muscle.-By pressing the thumb beneath the 
internal angular process of the frontal bone the cartilaginous pulley for the tendon of the 
Superior oblique muscle can be distinctly felt. We should be careful not to interfere 
with this pulley in any operation about the orbit. 
11. Lower Jaw.-The working of the condyle of the jaw vertically and from side 
to side can be distinctly felt [and seen] in front of the ear. When the mouth is opened 
wide the condyle advances out of the glenoid cavity on to the eminentia articularis, and 
returns into its socket when the mouth is shut. The muscle which causes this advance 
is the External pterygoid, and it gives the jaw a greater freedom of grinding motion. 
The posterior margin of the ramus of the lower jaw corresponds with a line drawn 
from the condyle to the angle. In opening abscesses in the parotid region the knife 
should not be introduced behind this line, for fear of wounding the external carotid 
artery. Punctures to any depth may be safely made in front of it. They are often 
necessary where inflammation of the parotid gland ensues after eruptive fevers and runs 
on to suppuration. The swelling, tension, and pain are most distressing. Owing to the 
fibrous framework of the gland the matter is not circumscribed, but diffused. One punc- 
ture is not enough. Three or more may be requisite. The blade of the knife should be 
held horizontally, so as to be less likely to injure the branches of the facial nerve. 
[These incisions are better made in the direction of radii from a point just below the 
ear.] We are not to be disappointed if no matter flows. The punctures give relief, and 
matter will probably exude the next day. 
[Zygoma.-In front of the ear lies the zygoma, one of the most marked and import- 
ant landmarks to the touch, and in lean persons to the eye. 
Seventh Nerve.-This nerve, after emerging from the stylo-mastoid foramen, 
passes into the parotid gland and is distributed to the facial muscles, its branches 
running toward the temple, the eye, the cheek, and the jaw. It can always readily 
be galvanized in facial palsy, etc. by placing one pole below the lobule of the ear and 
the other at the desired points of the face.] 
12. Parotid Duct.-A line drawn from the bottom of the lobe of the ear to mid- 
way between the nose and the mouth gives the course of the parotid duct. Opposite the 
second upper molar the duct opens by a papilla into the mouth [which can be readily 
seen]. The branch of the facial nerve which supplies the Buccinator runs with the 
duct. 
13. Temporal and Facial Arteries.-The pulsation of the trunk of the tem- 
poral artery can be felt between the root of the zygoma and the ear. This should be 
well known to and used by chloroformists. It is also a convenient pulse to feel in a 
sleeping patient. The facial artery can be distinctly felt as it passes over the body of 
the jaw at the anterior edge of the Masseter; again near the corner of the mouth close 
to the mucous membrane; and lastly by the side of the ala nasi up to the inner side of 
the tendo oculi. By holding the lips between the finger and thumb the coronary arteries 
are felt under the mucous membrane [and can be compressed here either by the finger 
and thumb or by a spring clip in hare-lip and other similar operations]. The facial vein 
does not accompany the tortuous artery, but runs a straight course from the inner angle 
of the eye to the front border of the Masseter, just behind the artery. 
14. Eyelids and Eyes.-The opening between the eyelids varies in size in differ- 
ent persons; hence more of the eyeball is seen in some than in others, and the eye 
appears larger. Although human eyes do vary a little in size, yet the actual difference 
is by no means so great as is generally supposed. The size of the fissure has much to 
do with the apparent size of the eye. Contrast the narrow fissure of the Chinese and 
Mongolian races and the apparent smallness of their eyes with those of Europeans. As 
a rule, the external angle of the lid is higher than the internal. When not exaggerated 
it gives the face an arch and pleasing expression. 
Evert the lids to see the Meibomian glands; observe their perpendicular arrangement 
in the substance of the tarsal cartilages. [Eversion of the upper lid is best done while THE FACE. 
1029 
the patient is looking down, by placing a pencil on the lid, next seizing the eyelashes, 
and then pushing the pencil gently downward, while by the lashes the free border of the 
lid is lifted over it. In case of a suspected foreign body, if it be not found on the lid, it 
must be remembered that it may easily be in the cornea and have been overlooked on 
the dark iris or pupil as a background. Oblique light will best reveal it if there.] 
The free borders of the lids are not bevelled, as described by J. L. Petit and most 
anatomists, " so as to form with the globe of the closed eye a triangular canal for the 
flow of the tears." On the contrary, it is easily seen that the lid-margins, when closed, 
come into accurate contact. The plane is not exactly horizontal, but slightly inclined 
upward. 
Every time the eye is shut the ball turns upward and inward, so that the cornea 
is completely covered by the upper lid. This may be well seen by raising the lid 
of a sleeping infant; also in cases of low fever when the lid is not completely closed. 
The upturning of the eye obviously clears the cornea and protects it from the light. 
A careful examination of the motion of the lower lid in the act of shutting the eye 
proves that it is a double motion. The lid is not only slightly raised, but drawn inward 
about of an inch. This second movement sweeps any particles of dust as well as 
moisture toward the inner canthus. 
15. Puncta Lachrymalia.-The puncta lachrymalia are distinctly visible [as two 
little black dots] at the inner angles of the lids. The lower punctum is larger and a 
little more external than the upper, so that they are not exactly opposite. The direction, 
too, of the puncta deserves notice. Their open mouths look a little backward, ready to 
imbibe the tears. When their proper bearing is lost, as in facial paralysis or by a cica- 
trix near the lid, the tears overflow the cheek. The length of the lachrymal canals is 
from three to four lines. The lower is a little shorter and wider than the upper. As 
each makes a little angle in its course about a line from its orifice, the lid should be 
drawn outward to straighten the canal when we introduce a probe. 
16. Lachrymal Sac.-To find the lachrymal sac, draw outward the eyelids to 
tighten the tendo oculi, which crosses the sac a little above its middle. A knife intro- 
duced just below the tendon close to the edge of the orbit would enter the sac. The 
angular artery and vein would be on the inner side of the incision. A probe directed in 
a line with the inner edge of the orbit-i. e. downward, outward, and backward-would 
pass down the nasal duct and appear in the inferior meatus of the nose. 
The tendo oculi serves many purposes besides giving attachment to the cartilages and 
muscles of the lids. One purpose is said to be to pump the tears into the lachrymal sac. 
Place a finger on the tendon and feel that it tightens every time the lids are closed. The 
tendon, being intimately connected to the sac, draws, as it tightens, the sac-wall outward 
and forward, and in this way it may pump along the lachrymal canals any fluid collected 
at the angle of the eye. [This is by the action of the Tensor tarsi (Horner's) muscle.] 
17. Nasal Duct.-The nasal duct is from six to eight lines long, and narrowest in 
the middle of its course. Its termination in the inferior meatus lies under the inferior 
spongy bone, about a quarter of an inch behind the bony edge of the nostril. The 
appearance of the orifice in the dry bone conveys no idea of its size and shape in life, for 
it is diminished by a valve-like fold of mucous membrane, so that it becomes in most 
cases a mere slit, not exceeding a line in diameter. 
The facility with which instruments can be introduced into the nasal opening of the 
duct depends upon its position as well as its size. This position varies in different 
instances. Sometimes it opens directly into the roof of the inferior meatus, in which 
case the hole is large and round, so that tears readily run into the nose. In other 
instances the opening is situated on the outer wall of the meatus, and is then always 
such a narrow fissure as to be hardly discernible. The practical conclusion, then, is, that 
a probe can be easily introduced when the opening is in the roof of the meatus, but not 
without difficulty and laceration of the mucous membrane when on the outer wall. This 
difficulty, indeed, may be increased by the narrowness of the meatus, arising from an 
unusual curvature of the spongy bone. 
18. Nose and Nasal Cavities.-The line where the cartilages of the nose are 
attached to the nasal and superior maxillary bones can be traced with precision. The 
close connection of the skin to the cartilages admits of no stretching; hence the acute 
pain felt in erysipelas and boils on the nose. The external aperture of the nose is always 
placed a little lower than the floor of the nostril, so that the nose must be pulled up 
before we can inspect its cavities. 
Looking into the nostrils, we find that the left is, in the majority of cases, narrower 1030 
LANDMARKS. 
than the right, owing to an inclination of the septum toward the left. A communication 
sometimes exists between them through a hole in the septum, as in the case of the cele- 
brated anatomist Hildebrandt. By stretching open the anterior nares we can get a view 
of the end of the inferior spongy bone. The middle spongy bone cannot be seen : its 
attachment to the ethmoid is high up, nearly opposite the tendo oculi. [With the head 
thrown well back this middle turbinated bone can be seen. It is important not to mis- 
take these spongy bones for polypi.] The cavities are so much narrowed transversely by 
the spongy bones that in the extraction of polypi it is better to dilate the blades of the 
forceps perpendicularly and near the septum. 
[Lips.-The color of the vermilion border the doctor ought always, and even uncon- 
sciously, to notice as a means of judging of the condition of the circulation and the 
character of the blood.] 
19. Mouth.-What can be seen and felt through the mouth? The upper surface 
of the tongue, " speculum primarum viarum" is a study in itself. We notice on its under 
surface a median furrow, on each side of which stands out the ranine vein, lying upon 
the prominent fibres of the lingualis. In the middle line of the floor of the mouth is the 
fraenum linguae, with the orifice of the duct of the submaxillary gland on each side of it. 
The gland itself can be detected immediately beneath the mucous membrane by feeling 
farther back near the angle of the jaw, at the same time pressing the gland upward from 
below. 
The long ridge of mucous membrane on each side of the floor contains the sublingual 
glands. 
We can feel the attachment of the Genio-hyo-glossi behind the symphysis of the jaw. 
The division of this attachment would enable a surgeon to draw the tongue more freely 
out of the mouth in any attempt to remove carcinoma extending far back into its 
root. 
There is great difference in the shape of the hard palate : this difference depends upon 
the depth of the alveolar processes. In some it forms a broad arch; in others it is nar- 
row and rises almost to a point like a Gothic arch, and materially impairs the tone of the 
voice. [The line of junction of the hard and soft palates is perceptible to the eye by a 
difference in color of the two surfaces, and also to the touch.] 
[Teeth.-In young children the question of the impending eruption of any tooth 
should always be settled by inspection and touch. The secondary incisor teeth should be 
examined if any possibility of syphilis exist. Before giving any anaesthetic artificial 
teeth should invariably be removed.] 
Throat.-To examine the throat well, the nose should be held so as to compel 
breathing through the mouth. Thus the soft palate will be raised, the palatine arches 
widened, and the tonsils and the back of the pharynx fairly exposed. Pressing the 
tongue downward, provided it be done very gently, is also of advantage. Rude treat- 
ment the tongue at once resists. The forefinger can be passed into the throat, beyond 
the epiglottis, as low as the bottom of the cricoid cartilage, and thus search the pharynx 
down to the top of the oesophagus and the hyoid space (on each side), where foreign 
bodies are so apt to lodge. [A forefinger of ordinary length can scarcely reach beyond the 
epiglottis.] The greater cornu of the hyoid bone can be felt as a distinct projection on 
either side. In introducing a tube into the oesophagus the finger should keep the instru- 
ment well against the back of the pharynx, so as to prevent its slipping into the larynx. 
Pass the finger between the teeth and the cheek and feel the anterior border of the 
coronoid process of the jaw. On the inner side of this process, between it and the 
tuberosity of the upper jaw, is a recess where a deeply-seated temporal abscess might 
burst or might be opened. Behind the last molar on the inner side of the upper jaw we 
can distinctly feel the hamular process of the sphenoid bone; also the lower part of the 
pterygoid fossa and the internal pterygoid plate. Behind and on the outer side of the 
last molar can be felt part of the back of the antrum and of the lower part of the exter- 
nal pterygoid plate. 
On the roof of the mouth we can feel the pulsation of the posterior palatine artery. 
Hemorrhage from this vessel can be arrested by plugging the orifice of the canal, which 
lies (not far from the surface) on the inner side of the last molar, about one-third of an 
inch in front of the hamular process. 
When the mouth is wide open the pterygo-maxillary ligament forms a prominent 
fold readily seen and felt beneath the mucous membrane behind the last molar teeth. A 
little below the attachment of this ligament to the lower jaw we can easily feel the gus- 
tatory nerve, as it runs close to the bone below the last molar tooth. The exact position THE NECK. 
1031 
of the nerve can be ascertained in one's own person by the acute pain on pressure. A 
division of the nerve, easily effected by a small incision, gives much temporary relief in 
cases of advanced carcinoma of the tongue. 
To feed a patient in spasmodic closure of the jaw it is well to know that there is 
behind the last molar teeth a space sufficient for the passage of a small tube into the 
mouth. 
Antrum.-Lift up the upper lip and examine the front wall of the antrum. The 
proper place in which to tap it is above the second bicuspid tooth, about one inch above 
the margin of the gum. [Percussion of the antrum will often give valuable information.] 
20. Posterior Nares.-A surgeon's finger should be familiar with the feel of the 
posterior nares and of all that is within reach behind the soft palate. This is important 
in relation to the attachment of polypi, to plugging the nostrils, and to the proper size 
of the plug. In the examination of this part of the back of the throat it is necessary 
to throw the head well back, because in this position nearly all the pharynx in front of 
the basilar process comes down below the level of the hard palate, and can be seen as 
well as felt. But when the skull is horizontal-i. e. at a right angle with the spine-the 
hard palate is on a level with the margin of the foramen magnum, and the parts cover- 
ing the basilar process are concealed from view. 
The head then being well back, introduce the forefinger behind the soft palate and 
turn it up toward the base of the skull. You feel the strong grip of the superior con- 
strictor. Hooking the finger well forward, you can feel the contour of the posterior 
nares. Their size depends upon the anterior, but rarely exceeds a small inch in the ver- 
tical diameter and a small half-inch in the transverse. The plug for the posterior nares 
should not be larger than this. Their plane is not perpendicular, but slopes a little for- 
ward. You can feel the septum formed by the vomer, and also the posterior end of the 
inferior spongy bone in each nostril. 
21. Tonsils.-Before taking leave of the throat look well at the position of the 
tonsils between the anterior and posterior half-arches of the palate. In a healthy state 
they should not project beyond the level of these arches. In all operations upon the 
tonsils we should remember the close proximity of the external carotid artery to their 
outer side. Nothing intervenes but the pharyngeal aponeurosis and the superior con- 
strictor of the pharynx. Hence the rule in operating on the tonsils, always to keep the 
point of the knife inward. 
In troublesome hemorrhage from the tonsils after an incision or removal, it is well to 
know that they are accessible to pressure, if necessary, by means 'of a padded stick or 
even a finger. 
22. Features.-A word or two on the lines of the face as indicative of expression. 
Every one pays unconscious homage to the study of physiognomy when, scanning the 
features of a stranger, he draws conclusions concerning his intelligence, disposition, and 
character. Without discussing how much physiognomy is really worth, there can be no 
doubt that it is a mistake to place it in the same category as phrenology, since the latter 
lacks that sound base of physiology which no one can deny to the former. 
A person fond of observing cannot fail to have arrived at the conclusion that a man's 
daily calling moulds his features. Place a soldier, a sailor, a compositor, and a clergy- 
man side by side, and who will not immediately detect a marked difference in their 
physiognomies ? 
The muscles of the features are generally described as arising from the bony fabric 
of the face, and as inserted into the nose, the corners of the mouth, and the lips. But 
this description gives a very inadequate idea of their true insertion. They drop fibres 
into the skin all along their course, so that there is hardly a point of the face which has 
not its little fibre to move it. The habitual recurrence of good dr evil thoughts, the 
indulgence in particular modes of life, call into play corresponding sets of muscles, 
which, by producing folds and wrinkles, give a permanent cast to the features and speak 
a language which all can understand, and which rarely misleads. Schiller puts this well 
when he says that " it is an admirable proof of Infinite Wisdom that what is noble and 
benevolent beautifies the human countenance ; what is base and hateful imprints upon it 
a revolting expression." 
THE NECK, 
[Skin.-In no part of the body can the differing thickness of the skin be more 
readily perceived than by pinching up a fold at the front, side, and back of the neck.] 1032 
LANDMARKS. 
23. Subcutaneous Veins.-Notice first the direction of the subcutaneous veins. 
The chief subcutaneous vein is the external jugular. Its course corresponds with a 
line drawn from the angle of the jaw to the middle of the clavicle, where it joins the 
subclavian. It is made more prominent by putting the Sterno-mastoid into action or by 
gentle pressure on the lower end of the vein. It is exceptionally joined by a branch 
which runs over the clavicle and is termed " jugulo-cephalic." The anterior jugular 
generally runs along the front border of the Sterno-mastoid. [The condition of these 
veins should be examined in all diseases causing respiratory disturbance, especially 
dyspnoea. In case of tricuspid regurgitation there will be a venous pulse seen. The 
stethoscope may also reveal a venous hum or musical note over these veins in 
anaemia.] 
24. Parts in Central Line : Os Hyoides.-Immediately below and nearly on a 
level with the lower jaw we feel the body of the os hyoides, and can trace backward on 
each side the whole length of the cornua. They might easily be broken by the grasp of 
a garrotter. Below the body of the os hyoides is the gap above the thyroid cartilage. 
This gap corresponds with the anterior thyro-hyoid ligament and the apex of the epi- 
glottis ; so that in cases of cut-throat in this situation nearly the whole of the epiglottis 
lies above the wound. 
Thyroid Cartilage.-The projection and depth of the notch in the thyroid 
cartilage, or " pomum Adami," varies in different persons. Between the notch and 
the hyoid bone there is a large bursa, which facilitates the play of the cartilage 
beneath the bone in deglutition. The notch does not appear till puberty, and is 
throughout life much less distinct in the female than the male. The finger can 
trace the upper borders and cornua of the thyroid cartilage: its lower cornua can 
be felt by the side of the cricoid. 
On each side of the thyroid cartilage we can recognize the lateral lobes of the thyroid 
gland. On the upper and front part of the gland we can distinctly feel the pulsation of 
the superior thyroid artery. This pulsation, coupled with the fact that the gland rises and 
falls with the larynx in deglutition, gives the best means of distinguishing a bronchocele 
from other tumors resembling it. 
Below the angle of the thyroid cartilage we feel the interval between it and the 
cricoid, which is occupied by the crico-thyroid membrane. In laryngotomy we cut 
through this membrane transversely close to the upper edge of the cricoid cartilage, 
in order that the incision may be as far as possible from the attachment of the vocal 
chords. 
25. Cricoid Cartilage.-The projection of the cricoid cartilage is a point of great 
interest to the surgeon, because it is his chief guide in opening the air-passages, and can 
always be felt even in infants, however young or fat. It corresponds to the interval 
between the fifth and sixth cervical vertebrae. The commencement of the oesophagus 
lies behind it: here, therefore, a foreign substance too large to be swallowed would prob- 
ably lodge, and might be felt externally. 
Again, a transverse line drawn from the cricoid cartilage horizontally across the neck 
would pass over the spot where the omo-hyoid crosses the common carotid. Just above 
this spot is the most convenient place for tying the artery. 
26. Those who have not directed their attention to the subject are hardly aware what 
a little distance there is between the cricoid cartilage and the upper part of the sternum. 
In a person of the average height, sitting with the neck in an easy position, the distance 
is barely one inch and a half. When the neck is well stretched about three-quarters of 
an inch more is gained. Thus we have (generally) not more than seven or eight rings 
of the trachea above the sternum. None of these rings can be felt externally. The 
second, third, and fourth are covered by the isthmus of the thyroid gland. The trachea, 
it should be remembered, recedes from the surface more and more as it descends, so that 
just above the sternum in a short, fat-necked adult the front of the trachea would be 
quite one inch and a half from the skin. 
27. Trachea.-In the dead subject nothing is more easy than to open the trachea: 
in the living this operation may be attended with the greatest difficulties. In urgent 
dyspnoea you must expect to find the patient with his head bent forward and the chin 
dropped, so as to relax as much as possible the parts. On raising his head a paroxysm 
of dyspnoea is almost sure to come on, threatening instant suffocation. The Elevator 
and Depressor muscles draw the trachea and larynx up and down with a rapidity and a 
force which may bring the cricoid cartilage within half an inch of the sternum. The 
great thyroid veins which descend in front of the trachea are sure to be distended. THE NECK. 
1033 
There may be a middle thyroid artery. In children the lobes of the thymus may extend 
up in front of the trachea, and the left vena innominata may cross it unusually high. 
Thus, the air-tube may be covered by important parts which ought not to be cut. 
Considering all these possible complications, the least difficult and the best mode of pro- 
ceeding is to open the trachea just below the cricoid cartilage, and, if more room be 
requisite, to pull down the isthmus of the thyroid gland, or in children to divide the 
cricoid itself. It is important that all the incisions be made strictly in the middle line, 
the " line of Safety." 
28. Sterno-mastoid Muscle.-The Sterno-mastoid muscle is the great surgical 
landmark of the neck. It stands out in bold relief when the head is turned toward the 
opposite shoulder [and the attempt to do so is resisted]. Its inner border overlaps the 
common carotid, which can be easily compressed for a short time against the spine about 
the level of the cricoid cartilage. The artery extends (generally) as high as the upper 
border of the thyroid cartilage, and corresponds with a line drawn from the sterno-clavic- 
ular joint to midway between the angle of the jaw and the mastoid process. 
Between, the sternal origins of the Sterno-mastoid is the fossa above the sternum, 
more or less perceptible in different necks. As it heaves and sinks alternately, especially 
in distressed breathing, it was called by the old anatomists " fonticulus gutturis." In 
beautiful necks, as seen in the " Venus," it is filled up by fat. 
Notice the interval between the sternal and clavicular origins of the Sterno-mas- 
toid. A knife introduced a very little way into this interval would wound, slanting 
inward, the common carotid-slanting outward, the internal jugular vein. These facts 
are of importance in performing the subcutaneous section of the tendon of this 
muscle. 
29. Sterno-clavicular Joint.-Many important parts lie behind the sterno-cla- 
vicular joint. There is the commencement of the vena innominata; behind this comes 
the common carotid on the left side, and the division of the arteria innominata on the 
right. Deeper still, the apex of the lung rises into the neck. 
In a child the arteria innominata often lies in front of the trachea and divides a little 
higher than the joint-a point to be remembered in tracheotomy (27). 
30. Apex of the Lung in the Neck.-The extent to which the apex of the lung 
rises into the neck is greater than is generally supposed. Many observations in refer- 
ence to this point lead to the conclusion that the lung rises behind the Sterno-mastoid, on 
an average, one inch and a half above the clavicle ; in persons with long necks as much 
as two inches. The apex of the lung and pleura is covered by the clavicular origin of 
the Sterno-mastoid, the Sterno-thyroid, and a part of the Scalenus anticus. It is also 
crossed by the subclavian vessels in the first part of their course. As this cervical por- 
tion of lung is peculiarly liable to tubercular disease, it should always be carefully 
examined. Its condition may be ascertained by percussion near the sternal end of the 
clavicle. 
31. Supraclavicular Fossa.-The hollow above the clavicle, between the Sterno- 
mastoid and the Trapezius, is very manifest in emaciation and old age. [Shrugging the 
shoulders makes it exceedingly pronounced.] Notice the termination here of the exter- 
nal jugular vein. In some necks only a small depression is visible, particularly when 
the Trapezius has a broad insertion into the clavicle and comes well forward, so that its 
front border gives a graceful contour to the base of the neck. 
32. Subclavian Artery.-In the supraclavicular fossa, near the outer border of 
the Sterno-mastoid and about one inch above the clavicle, we feel the pulsation of the 
subclavian artery. Here the artery lies upon the first rib, and can be effectually com- 
pressed. A little pressure is sufficient. But the pressure must be made in the right 
direction, or the artery will be pressed off the rib instead of against it. The plane of 
the rib is such that the pressure, to be effectual, must be made in a direction downward 
and a little inward. It is best to stand behind the shoulder and make the pressure with 
one thumb. 
It is worth remembering that the outer border of the Sterno-mastoid corresponds 
pretty nearly with the outer edge of the Scalenus anticus, which is the surgical guide to 
the subclavian artery. 
[Phrenic Nerve.-As the phrenic nerve passes over the Scalenus anticus, it can 
now be readily located. If it is to be galvanized, one pole of the battery should be 
placed in this fossa and the other over the Diaphragm.] 
By pressing deeply at the upper part of the supraclavicular fossa, the transverse pro- 
cess of the seventh cervical vertebra can be distinctly felt. 1034 
LANDMARKS. 
In long and thin necks a thin cord is perceptible running nearly parallel with and just 
above the clavicle. It is the posterior belly of the Omo-hyoideus. See it rising and 
falling in breathing, and making tense during inspiration that part of the cervical fascia 
which lies over the cervical portion of the lung. Thus it may be said to be in all 
respects a muscle of inspiration, co-operating with the Sterno-mastoid and Scaleni. In 
the language of transcendental anatomy, we may say that the central tendon of the Omo- 
hyoid represents a rudimentary cervical rib. Its posterior belly is analogous to a serra- 
tion of the Serratus magnus, its anterior belly to a Sterno-hyoid. 
THE CHEST. 
33. As a rule, the right half of the chest is slightly larger than the left. Of 92 
persons of the male sex and good constitutions, 71 had the right side the larger, 11 the 
left; 10 had both sides equal. The maximum of difference in favor of the right was 
one inch and a quarter. The measurements were made on a plane with the nipple. 
34. Peculiarities in the Female.-The chest of the female differs from that of 
the male in the following points: Its general capacity is less; the sternum is shorter; 
the upper opening is larger in proportion to the lower; the upper ribs are more movable, 
and therefore permit a greater enlargement of the chest at its upper part in adaptation to 
the requirements of pregnancy. 
35. The top of the sternum is on a level with the second dorsal vertebra, and the 
available space between the top of the sternum and the spine is hardly more than two 
inches.1 
36. Parts behind First Bone of Sternum.-There is little or no lung behind 
the first bone of the sternum, the space being occupied by the trachea and large vessels, 
as follows: 
The left vena innominata crosses the sternum just below the upper border. Next 
come the great primary branches of the arch of the aorta. Deeper still is the trachea 
dividing into its two bronchi opposite the junction of the first and second bones of the 
sternum. Deepest of all is the oesophagus. 
About one inch from the upper border of the sternum is the highest part of the 
aorta, which lies on the bifurcation of the trachea. 
37. The course of the arteria innominata corresponds with a line drawn from the 
middle of the junction of the first with the second bone of the sternum to the right 
sterno-clavicular joint. When the artery rises higher than usual into the neck its pulsa- 
tion can be felt in the fossa above the sternum. 
38. Rules for Counting' the Ribs.-In fat persons it is often difficult to count 
the ribs; hence the following rules may be useful: 
a. The finger passed down from the top of the sternum soon comes to a transverse 
projection, slight but always to be felt [and generally seen], at the junction of the first 
with the second bone of the sternum. This corresponds with the level of the cartilage 
of the second rib. 
b. The nipple of the male is placed, in the great majority of cases, between the 
fourth and the fifth ribs, about three-quarters of an inch external to their cartilages. 
c. The lower external border of the Pectoralis major corresponds with the direction 
of the fifth rib. 
d. A line drawn horizontally from the nipple round the chest cuts the sixth intercos- 
tal space midway between the sternum and the spine. This is a useful rule in tapping 
the chest. 
e. When the arm is raised the highest visible digitation of the Serratus magnus cor- 
responds with the sixth rib. The digitations below this correspond respectively writh the 
seventh and eighth ribs. 
f. The scapula lies on the ribs from the second to the seventh, inclusive. 
g. The eleventh and twelfth ribs can be felt even in corpulent persons outside the 
Erector spinae, sloping downward. 
h. One should remember the fact that the sternal end of each rib lies on a lower level 
than its corresponding vertebra. For instance, a line drawn horizontally backward 
1 In several adult normal skeletons measured in the Hunterian Museum the average diameters 
of the upper opening of the chest were-antero-posterior, about 2| inches ; transverse, about 4| 
inches. In the skeleton of O'Brien, the Irish giant, the antero-posterior diameter measures 4 inches, 
the transverse 6|. THE CHEST. 
1035 
from the middle of the third costal cartilage at its junction with the sternum to the spine 
would touch the body, not of the third dorsal vertebra, but of the sixth. Again, the 
end of the sternum would be on about the level of the tenth dorsal vertebra. Much 
latitude must be allowed here for variation in the length of the sternum, especially in 
women. 
39. Interval below Clavicle.-Immediately below the clavicle we recognize the tri- 
angular interval between the Pectoralis major and the Deltoid. This space varies in different 
cases, depending on the distance between the muscles. It is important as a guide to the 
coracoid process and the axillary artery. In a case of injury to the shoulder, to ascer- 
tain whether the coracoid process is broken, carry the arm outward to put the Deltoid and 
Pectoral muscles on the stretch and make manifest the space between their opposite bor- 
ders. Pressing the thumb into the space, we can feel the inner side of the coracoid pro- 
cess, the apex being under the fibres of the Deltoid; thus it is easy to ascertain whether 
it be broken. Moreover, this space corresponds with the line of the axillary artery; 
here its pulsation can be distinctly felt, and here it can be compressed (but not easily or 
for long) against the second rib. 
40. Internal Mammary Artery.-The line of the internal mammary artery runs 
perpendicularly behind the cartilages of the ribs, about half an inch from the sternum. 
The perforating branch through the second intercostal space is generally the largest. 
41. Outline of Heart on Chest-wall.-To have a general idea of the form and 
position of the heart map its outline on the wall of the chest [by an aniline pencil], as 
follows: 
а. To define the base draw a transverse line across the sternum corresponding with 
the upper borders of the third costal cartilages: continue the line half an inch to the 
right of the sternum and one inch to the left. 
б. To find the apex mark a point about two inches below the left nipple and one inch 
Fig. 683. 
Outline of the Heart, its Valves, and the Lungs. 
to its sternal side. This point will be between the fifth and sixth ribs [and can generally 
be determined by feeling the apex beat], 
c. To find the lower border (which lies on the central tendon of the Diaphragm) 
draw a line, slightly curved downward, from the apex across the bottom of the sternum 
(not the ensiform cartilage) as far as its right edge. 1036 
LANDMARKS. 
d. To define the right border (formed by the right auricle) continue the last line 
upward with an outward curve, so as to join the right end of the base. 
e. To define the left border (formed by the left ventricle) draw a line curving to the 
left, but not including the nipple, from the left end of the base to the apex. 
Such an outline (seen in the cut above with angles rounded off) shows that the apex 
of the heart points downward and toward the left, the base a little upward and toward 
the right; that the greater part of it lies in the left half of the chest; and that the only 
part which lies to the right of the sternum is the right auricle. A needle introduced in 
the third, the fourth, or the fifth right intercostal space close to the sternum would pene- 
trate the lung and the right auricle. 
A needle passed through the second intercostal space close to the right side of the 
sternum would, after passing through the lung, enter the pericardium and the most 
prominent part of the bulge of the aorta. 
A needle passed through the first intercostal space close to the right side of the 
sternum would pass through the lung and enter the superior vena cava above the peri- 
cardium. 
42. The best definition of that part of the praecordial region which is less resonant 
on percussion was given by Dr. Latham years ago in his Clinical Lectures: " Make a 
circle of two inches in diameter round a point midway between the nipple and the end 
of the sternum. This circle will define sufficiently for ail practical purposes that part of 
the heart which lies immediately behind the wall of the chest and is not covered by lung 
or pleura." 
Apex of the Heart.-The apex of the heart pulsates between the fifth and sixth 
ribs, two inches below the nipple and one inch to its sternal side. The place and extent, 
however, of the heart's impulse vary a little with the position of the body. Of this any 
one may convince himself by leaning forward, backward, on this side, and on that, feel- 
ing at the same time the heart. Inspiration and expiration also alter the position of the 
heart. In a deep inspiration it may descend half an inch and can be felt beating at the 
pit of the stomach. 
43. Valves of the Heart.-The aortic valves lie behind the third intercostal space, 
close to the left side of the sternum. 
The pulmonary valves lie in front of the aortic, behind the junction of the third 
costal cartilage on the left side with the sternum. 
The tricuspid valves lie behind the middle of the sternum, about the level of the 
fourth costal cartilage. 
The mitral valves (the deepest of all) lie behind the third intercostal space, about one 
inch to the left of the sternum. 
Thus these valves are so situated that the mouth of an ordinary-sized stethoscope 
will cover a portion of them all, if placed over the sternal end of the third intercostal 
space on the left side. All are covered by a thin layer of lung; therefore we hear 
their action better when the breathing is for a moment suspended [in expiration]. 
[Where to Auscult the Valves of the Heart.-The valves being so close 
together, it is evident that to discriminate the sound of one from that of the others we 
must be able to auscult them separately; and accordingly we follow the diverging course 
of the blood-currents they transmit. Hence, 
The aortic valve is best ausculted over the second intercostal space at the right bor- 
der of the sternum; it can also be heard over the aorta in the back from the third to the 
ninth dorsal spines, especially if there be any murmur; 
The pulmonary valve, over the second space at the left border of the sternum; 
The tricuspid valve, over the middle of the sternum above the ensiform cartilage ; and 
The mitral valve, over the apex of the heart.] 
44. Outline of the Lungs.-Now let us trace on the chest the outline of the 
lungs with as much precision as their expansion and contraction in breathing permit. 
(See Fig. 683.) 
45. The apex of each lung rises into the neck behind the sternal end of the clavicle 
and Sterno-mastoid muscle as much as an inch and a half: in females rather higher than 
in males (30). From the sternal ends of the clavicles the lungs converge, so that their 
thin edges almost meet in the mesial line on a level with the second costal cartilage. 
Thus there is little or no lung behind the first bone of the sternum. From the level of 
the second costal cartilage to the level of the fourth the margins of the lungs run paral- 
lel or nearly so close behind the middle of the sternum ; consequently their thin edges 
overlap the great vessels and valves at the base of the heart. THE BACK. 
1037 
Below the level of the fourth costal cartilage the margins of the lungs diverge, but 
not in an equal degree. The margin of the right corresponds with the direction of the 
cartilage of the sixth rib: the margin of the left, being notched for the heart, runs 
behind the cartilage of the fourth. A line drawn perpendicularly from the nipple would 
find the lung margin about the lowest part of the sixth rib. Laterally-i. e. in the axil- 
lary line-the lung margin comes down as low as the eighth rib: posteriorly-i. e. in the 
dorsal or scapular line-it descends as low as the tenth. 
It should be remembered that in a deep inspiration the lung margins descend about 
one inch and a half. 
In children the lungs are separated in front by the thymus gland. Allowance should 
be made for this. About the approach of puberty the thymus disappears. 
46. Anterior Mediastinum.-The direction of the anterior mediastinum is not 
straight down the middle of the sternum, but slants a little to the left, owing to the 
position of the heart. The right pleural sac generally encroaches a little upon the left, 
behind the middle of the sternum. A needle introduced through the middle of the 
sternum opposite the third or the fourth rib would go through the right pleura. 
47. Reflection of Pleura.-The reflection of the pleura from the wall of the chest 
on to the Diaphragm corresponds with a sloping line drawn from the bottom of the ster- 
num over the cartilages of the ribs down to the lower border of the last rib. 
Since the pleura lines the inside of the last rib, a musket-ball or other foreign body 
loose in the pleural sac and rolling on the Diaphragm might fall to the lowest part of 
the sac, which would be between the eleventh and twelfth ribs. The ball might be 
extracted here. The chest might also be tapped here, but not with a trocar, since a 
trocar would penetrate both layers of pleura and go through the Diaphragm into the 
abdomen. 
The operation should be done cautiously, by an incision beginning about two inches 
from the spine on the outer bordei' of the Erector spinae, on a level between the spines 
of the eleventh and twelfth dorsal vertebrae. The intercostal artery will not be injured 
if the opening be made below the middle of the space, which is very wide.1 
THE BACK. 
48. Median Furrow.-In a muscular man a furrow caused by the prominence of 
the Erector spinae on each side runs down the middle of the back. The lower end of the 
furrow corresponds with the interval between the spine of the last lumbar and that of 
the first sacral vertebra. [It must be observed that in the skeleton and the body fur- 
rows and prominences, hills and hollows, are, as a general rule, reversed. Bony projec- 
tions in the skeleton, as a rule, are for muscular origins. As at a little distance from the 
■origin the muscular bellies swell out, such prominences lie at the bottom of depressions. 
But when long sickness wastes the soft parts the form of the skeleton reappears, and 
such bony prominences then become the favorite seats of bed-sores.] 
49. Spines of the Vertebrae.-A little friction with the fingers down the back- 
bone will cause the spines of the vertebrae to be tipped with red, so that they can be easily 
counted and any deviation from the straight line detected. Still, it is worth remember- 
ing that the spine of the third dorsal is on a level with the commencement of the spine 
•of the scapula; that the spine of the seventh dorsal is on a level with the inferior angle 
of the scapula; that the spine of the last dorsal is on a level with the head of the 
last rib. 
Division of the Trachea.-The division of the trachea is opposite the spine of 
the third, in some cases the fourth, dorsal vertebra. In front this division is on the level 
of the junction of the first with the second bone of the sternum. 
The root of the spine of the scapula is marked by a slight dimple in the skin. This 
is on a level with the third intercostal space. A stethoscope placed on the inner side of 
the dimple would cover the bronchus, more especially the right, since it is nearer to the 
chest-wall. 
Make a man lean forward, with his arms folded across the chest; this will make 
prominent the spines of the vertebrae. The lower border of the Trapezius will guide 
you to the spine of the twelfth dorsal vertebra. 
1 Special experiments upon this subject were made many years ago by the late Professor Quekett 
in the work-rooms of the College of Surgeons. 1038 
LANDMARKS. 
50. The place where the Kidney is most accessible to pressure is below the last rib, 
on the outer edge of the Erector spinae. 
51. The highest part of the Ilium is about the level of the fourth lumbar spine. 
The best incision for opening the descending colon is in a slightly sloping line beginning 
at the outer edge of the Erector spinae, midway between the crest of the ilium and the 
last rib, and continued across the flank for three inches or more, according to the amount 
of subcutaneous fat. [This ilio-costal space varies very much in its vertical measure- 
ment. I have seen it only a finger's breadth, and again a whole hand's breadth. The 
line of the colon passes through it vertically about half an inch behind the middle of the 
crest of the ilium (Heath).] 
52. In the pit of the neck we can feel the Trapezius and the ligamentum 
nuchae. By pressing deeply we detect the forked prominent spine of the second 
cervical vertebra. 
53. The spines of the third, fourth, and fifth cervical vertebrae recede from the sur- 
face to permit free extension of the neck, and cannot often be felt. But the spines of 
the sixth and seventh (v. proininens) [and first dorsal] stand out well. 
54. Notice that most of the spines of the dorsal vertebrae, owing to their obliquity, 
do not tally with the heads of their corresponding ribs. Thus, the spine of the second 
dorsal corresponds with the head of the third rib, the spine of the third dorsal with the 
head of the fourth rib, and so on till we come to the eleventh and twelfth dorsal verte- 
bras, which do tally with their corresponding ribs. All this, however, is best seen in the 
skeleton. 
55. The spines of the vertebrae may be useful as landmarks indicative of the levels 
of important organs. I have therefore arranged them in a tabular form, thus: 
Tabular Plan of Parts opposite the Spines of the Vertebrae. 
Cervical. 
5th. Cricoid cartilage. (Esophagus begins. 
7th. Apex of lung: higher in the female than in the male (30). 
1st. 
2d. 
3d. Aorta reaches spine. Apex of lower lobe of lung. Angle of bifurcation of 
trachea (49). 
4th. Aortic arch ends. Upper level of heart. 
5 th. 
6th. 
7 th. 
8th. Lower level of heart. Central tendon of Diaphragm. 
9th. (Esophagus and vena cava through Diaphragm. Upper edge of spleen. 
10th. Lower edge of lung. Liver comes to surface posteriorly. Cardiac orifice of 
stomach. 
11th. Lower border of spleen. Renal capsule. 
12th. Lowest part of pleura. Aorta through Diaphragm. Pylorus. 
Dorsal. 
Lumbar. 
1st. Renal arteries. Pelvis of kidney (83). 
2d. Termination of spinal cord. Pancreas. Duodenum just below. Receptaculum 
chyli. 
3d. Umbilicus. Lower border of kidney. , 
4th. Division of aorta (65). Highest part of ilium. 
5 th. 
56. Origins of the Spinal Nerves.-It is useful to know opposite what vertebrae 
the spinal nerves in the different regions arise from the spinal cord. They arise as fol- 
lows : 
The origins of the eight cervical nerves correspond to the interval between the occi- 
put and the sixth cervical spine. 
The origins of the first six dorsal nerves correspond to the interval between the sixth 
cervical and the fourth dorsal spines. 
The origins of the six lower dorsal nerves correspond to the interval between the 
fourth and the eleventh dorsal spines. 
The origins of the five lumbar nerves correspond to the interval between the eleventh 
and twelfth dorsal spines. 
The origins of the five sacral nerves correspond to the spines of the last dorsal and 
the first lumbar vertebrae. THE BACK. 
1039 
[Fig. 684. 
1 c 
■ 2 
3 
4 
5 
i 6 
■ 7 
• 8 
ID 
• 2 
■ 3 
■ 4 
• 5 
• 6 
• 7 
■ 8 
■ 9 
•10 
■11 
12 
1 L 
2 
3 
4 
5 
1 S 
■ 2 
1 3 
4 
5 
■ Co 
MOTOR. 
SENSORY. 
REFLEX. 
St. Mastoid. 
Trapezius. 
- Neck and Scalp. 
j- Diaphragm. 
> Neck and Shoulder. 
1 Serratus. 
J Shoulder, j 
Shoulder. 
- Scapular. 
Arm. [- mus. 
Arm. 
Hand. J 
Hand. 
(ulnar lowest.) 
- 
■ 
1 
Front of Thorax. 
Intercostal 
- Epigastric. 
muscles. 
- Ensiform area. 
Abdominal 
muscles. 
Abdomen 
(Umbilicus 10th). 
Abdominal. 
' Buttock, upper 
J 
j part. 
s 
1 
Groin and Scrotum 
Flexors, hip. 
(front). 
f outer side. 
- Cremasteric. 
Extensors, knee. 
1 
Thigh 1 front. 
1 Knee-jerk. 
1 Adductors. 'j 
J 
(inner side. 
_ Abductors. ( hip. 
■ 
I 
jeg, inner side. 
Buttock, lower 
■ Gluteal. 
J Extensors (?) J 
) Flexors, knee (?) 
) Muscles of leg 
J moving foot. 
Perineal and Anal 
1 
part. 
Back of Thigh. 
Leg ) except 
and > inner 
Foot J part. 
Foot-clonus. 
Plantar. 
muscles. 
1 
'erineum and 
Anus. 
Skin from Coccyx 
to Anus. 
ci- 
2- 
3- 
4- 
5' 
6- 
7- 
D 1- 
2- 
3- 
4- 
5- 
6- 
7- 
8- 
9 
10 
11 
12 
L 1 
2 
3 
4 
5 
S 
Co 
Diagram and Table showing the Approximate Relation to the Spinal Nerves of the Various Motor, Sensory, and 
Reflex Functions of the Spinal Cord (from anatomical and pathological data). (From Gowers.) 
57. Movements of the Spine.-The movements of which the spine is capable 
are threefold : 1, flexion and extension ; 2. lateral inclination ; 3, torsion. Flexion and 
extension are freest between the third and sixth cervical vertebras, between the eleventh 
dorsal and the second lumbar, and between the last lumbar and the sacrum. This is well 
marked in severe cases of opisthotonos, where the body is supported on the back of the 
head and heels.1 
Still better may it be observed when a mountebank bends backward and touches the 
ground with his head. 
The lateral movement is freest in the neck and the loins. 
The movement of torsion or rotation round its own axis may be proved by the fol- 
lowing experiment: Seated upright, with the back and shoulders well applied against 
1 See a beautiful illustration of this in Sir C. Bell's Anatomy of Expression, p. 160. 1040 
LANDMARKS. 
the back of a chair, we can turn the head and neck as far as 70°. Leaning forward, 
so as to let the dorsal and lumbar vertebrae come into play, we can turn 30° more. 
[The atlo-axoid movement amounts to 25° to each side, the remaining cervical verte- 
brae give 45° more, making 70° in the neck; the dorso-lumbar movement is about 30°, 
to which the hips add from 65° to 80°, or a total rotation of 165° to 180°. • For pur- 
poses of observation we gain, in addition to this, about 70° more for the eyeball, so 
that, posteriorly as well as anteriorly, the field of vision right and left overlaps very 
largely.] 
Fig. 685. 
Opisthotonos (after Bell). 
58. Position and Motions of Scapula.-There are a few points worthy of 
observation about the scapula. It covers the ribs from the second to the seventh 
inclusive. We can feel its superior angle covered by the trapezius. The inferior 
angle is covered by the Latissimus dorsi, which keeps it well applied against the 
ribs in the strong and athletic; but in weak and consumptive persons the lower 
angles of the scapulae project like wings-hence the term " scapulae alatee." 
A line drawn horizontally from the spine of the sixth dorsal vertebra over the 
inferior angle of the scapula gives the upper border of the Latissimus dorsi. 
Another line drawn from the root of the spine of the scapula to the spine of the 
last dorsal vertebra gives the lower border of the Trapezius, which stands a little in 
relief. 
59. The sliding movement of the scapula on the chest can be properly understood only 
on the living subject. It can move not only upward and downward, as in shrugging the 
shoulders-backward and forward, as in throwing back the shoulders-but it has a rota- 
tory movement round a movable centre. This rotation is seen while the arm is being 
raised from the horizontal to the vertical position, and is effected by the co-operation of 
the Trapezius with the Serratus magnus. The glenoid cavity is thus made to look 
upward, the inferior angle slides forward, and is well held under the Latissimus 
dorsi. 
60. For the medical examination of the back the patient should sit with the arms 
hanging between his thighs, to lower the scapulae as much as possible. In this position 
the spine of the scapula corresponds (nearly) with the fissure between the upper and 
lower lobes of the lung, the apex of the lower lobe being about the level of the third 
rib. 
[Usually I prefer to have the arms folded across the chest-obviously the better 
position for women-and it uncovers the back rather better. 
The remarkable mobility of the scapula is best seen by contrasting this position with 
the place of the scapula when the shoulders are thrown well back. In this last position 
the lower angles of the scapulae will be two or three inches apart, while in the former 
this interval measures from twelve to sixteen inches. Moreover, so soon as the arm is 
lifted from the trunk at an angle of 30° or 40°, and long before it reaches the horizontal 
line, the scapula begins to move. This mobility of the scapula explains readily the great 
range of movement, and therefore the usefulness of the arm, in cases of ankylosis of the 
shoulder-joint.] THE ABDOMEN. 
1041 
THE ABDOMEN. 
The student is assumed to be familiar with the conventional lines dividing the abdo- 
men into regions. 
61. Abdominal Lines.-The linea alba, or central line of the abdomen, marks the 
union of the aponeuroses of the abdominal muscles. It runs from the apex of the ensi- 
form cartilage to the symphysis pubis. As this line is the thinnest and least vascular 
part of the abdominal wall, we make our incision along it in ovariotomy [Caesarean sec- 
tion, and most other operations on the abdominal and pelvic viscera] and in the high 
operation of lithotomy; in it we tap the abdomen in ascites and the distended bladder in 
retention of urine. 
The so-called " linea semilunaris," at the outer border of the sheath of the rectus, 
corresponds with a line drawn slightly curved (with the concavity toward the linea alba) 
from the lowest part of the seventh rib to the spine of the pubes. This line would be 
in an adult about three inches from the umbilicus, but in an abdomen distended by dropsy 
or other cause the distance is increased in proportion. [These lines of adhesion in the 
abdominal wall limit extravasations, emphysema, etc. between their layers.] 
It is important to know the position of the lineae transversal, or tendinous intersec- 
tions across the rectus abdominis. There are rarely any below the umbilicus, and gen- 
erally three above it. The first is about the level of the umbilicus. The second is 
about four inches higher; that is, about the level of the lowest part of the tenth rib. 
These are the principal lines, and they divide the upper part of each rectus into two 
nearly quadrilateral portions, an upper and a lower; of these, those on the right side are 
a trifle larger than on the left. We see these muscular squares pretty plainly in some 
athletic subjects. Much more frequently we see them, too much exaggerated, on canvas 
and in marble. Artists are apt to exaggerate them and make the front of the belly too 
much like a chess-board. It is lucky for them that all the world does not see with ana- 
tomical eyes. 
A familiarity with the shape and position of these divisions of the rectus is of import- 
ance, lest we should, in ignorance, make a mistake in our diagnosis. A spasmodic con- 
traction of one of these divisions, particularly the upper, or a collection of matter within 
its sheath, has been frequently mistaken for deep-seated abdominal disease. 
In the erect position the anterior superior spines of the ilia are a little below the level 
of the promontory of the sacrum. The bifurcation of the aorta is on about the level of 
the highest part of the crest of the ilium. 
62. Umbilicus.-The umbilicus is not midway between the ensiform cartilage and 
the pubes, but rather nearer to the pubes. In all cases it is situated above the centre of 
a man's height. It is a vulgar error to say that when a man lies with legs and arms 
outstretched and a circle is drawn round him, the umbilicus lies in the centre of it. This 
central point is in most persons just above the pubes. 
[From the vertex to the umbilicus, the whole height being taken as the unit of meas- 
urement, is .550 at birth-/. e. the mid-point is above the navel. At two years it is at 
the navel, and gradually falls as the legs grow longer, until at thirty the mid-point is 
just below the pubes in men (half an inch) and just above it in women. Moreover, 
while at three to five years of age the whole height is equal to the distance between the 
outstretched finger-tips, before that age it is somewhat greater, and in adult life is much 
less.] 
In very corpulent persons two deep transverse furrows run across the abdomen. One 
runs across the navel and completely conceals it. The other is lower down, just above 
the fat of the pubes. In tapping the bladder above the pubes in such a case the trocar 
should be introduced where this line intersects the linea alba. 
Although the position of the umbilicus varies a little in different persons as the abdo- 
men is unusually protuberant or the reverse, still, as a general rule, it is placed about 
the level of the body of the third lumbar vertebra. Now, since the aorta divides a little 
below the middle of the fourth lumbar, it follows that the best place to apply pressure 
on this great vessel is one inch below the umbilicus and slightly to the left of it (65). 
That the aorta can, under favorable circumstances, be compressed under chloroform suffi- 
ciently to cure an aneurism below it is proved by recorded cases, and by none more effect- 
ually than by a case related in the second volume of the Reports of St. Bartholomew's 
Hospital. It may be asked, Why not apply pressure on the aorta above the umbilicus ? 
The answer is, that the aorta above the umbilicus is farther from the surface, and is, 
moreover, covered by important structures upon which pressure would be dangerous. 1042 
LANDMARKS. 
[The umbilicus is a point of fusion of all the tissues of the abdominal wall. Hence, 
it becomes a most valuable guide as to the depth of our position when cutting through 
the abdominal wall to attack tumors, etc. in the abdominal cavity. Attempt to sweep 
the finger under the umbilicus: if through the abdominal wall and upon the tumor, the 
finger will meet with no obstacle other than adhesions, which can be destroyed; if, on 
the contrary, still in the thickness of the abdominal wall (and it is not always easy to 
distinguish this in any other way), the finger will be absolutely arrested at the navel, and 
no force will carry it farther. 
The umbilicus being the remains of an opening into the belly, when stretched by 
ascites, as the fluid can insinuate itself everywhere, it usually bulges out considerably; 
but in tumors this cannot be the case. 
Again, it affords passage to the contents of the belly not uncommonly, and so we 
have umbilical herniae; and sometimes ovarian fluids, pus in peritonitis, and entozoa 
escape here. 
It is also an important point for measurements, sometimes used in fractures and dislo- 
cations of the hip and femur and in fractures of the anterior superior spines, and always 
in measuring the size of tumors from it to the ensiform, the pubes, and the two iliac 
spines. 
The umbilicus is always much deeper and wider in women than in men.] 
63. Parts behind the Linea Alba.-Let us next consider what viscera lie imme- 
diately behind the linea alba. For two or three fingers' breadth below the ensiform car- 
tilage there is the left lobe of the liver, which here crosses the middle line. Below the 
edge of the liver comes the stomach, more or less in contact with the linea alba according 
to its degree of distension. In extreme distension the stomach pushes everything out of 
the way, and occupies all the room between the liver and the umbilicus. When empty 
and contracted it retreats behind the liver and lies flat in front of the pancreas at the 
back of the abdomen, thus giving rise to the hollow termed the " pit of the stomach." 
But as the stomach distends it makes a considerable fulness where there was a pit. The 
middle of the transverse colon lies above the umbilicus, occupying space (vertically two 
or three inches) according to its distension. Behind and below the umbilicus, supposing 
the bladder contracted, are the small intestines, covered by the great omentum. 
64. Peritoneum.-The peritoneum is in contact with the linea alba all the way 
down to the pubes when the bladder is empty. But when the bladder distends it raises 
the peritoneum from the middle line above the pubes, so that with a bladder distended 
halfway up to the umbilicus there is a space of nearly two inches above the symphysis 
where the bladder may be tapped without risk of injury to the peritoneum. For the 
same reason we have space sufficient for the successful performance of the high operation 
for stone. This fact in anatomy must have been well understood by Jean de Dot, the 
smith at Amsterdam, who in the seventeenth century cut himself in the linea alba above 
the pubes and took out of his bladder a stone as large as a hen's egg. The stone, the 
knife, and the portrait of the operator may be seen to this day in the museum at Leyden. 
65. Division of the Aorta.-The aorta generally divides at a point one inch and 
a half below the umbilicus. A more reliable guide to this division than the umbilicus is 
a point (a very little to the left) of the middle line about the level of the highest part 
of the crest of the ilium. A line drawn with a slight curve outward from this point to 
the groin, where the pulsation of the common femoral can be distinctly felt (rather nearer 
to the pubes than the ilium), gives the direction of the common iliac and external iliac 
arteries. About the first two inches of this line belong to the common iliac, the remain- 
der to the external. Slight pressure readily detects the pulsation of the external iliac 
above Poupart's ligament. 
As a rule, the length of the common iliac is about two inches, but it should be 
remembered there are frequent deviations. It may be between three-quarters of an inch 
and three inches and a half long. These varieties may arise either from a high division 
of the aorta or a low division of the common iliac, or both. It is impossible to ascertain 
during life what is its length in a given instance, for there is no necessary relation 
between its length and the height of the stature. It is often short in tall men, and vice 
versa. Anatomists generally describe the right as a trifle longer than the left, but their 
average length is pretty nearly the same. 
66. Mr. Abernethy, who in the year 1796 first put a ligature round the external iliac, 
made his incision in the line of the artery. But the easiest and safest way to reach the 
vessel is by an incision (recommended in the first instance by Sir Astley Cooper, and now 
generally adopted) beginning just on the inner side of the artery, a little above Poupart's THE ABDOMEN. 
1043 
ligament, and continued upward and outward a little beyond the spine of the ilium. 
The same incision extended farther in the same direction would reach the common 
iliac. 
67. Bony Prominences.-The anterior superior spine of the ilium, the spine of 
the pubes, and the line of Poupart's ligament are landmarks with which every surgeon 
should be thoroughly familiar. 
68. Spine of the Ilium.-The spine of the ilium is the spot from which we meas- 
ure the length of the lower extremity. It is a valuable landmark in determining the 
nature of injuries to the pelvis and the hip. The thumb easily feels the spine, even in 
fat persons. Its position with regard to the trochanter major should be carefully exam- 
ined. The best way to do this is to place the thumbs firmly on the opposite spines and 
to grasp the trochanters with the fingers. Any abnormal position on one side is thus 
easily ascertained with the sound side as a guide. 
[In all such measurements it is of the utmost importance that a line joining the two 
spines should be at right angles to the axis of the body, or the measurements cannot 
fail to be inaccurate. The spines also are so open to error as points of measurement (for 
we scarcely ever can get precisely corresponding points on the two sides) that I have 
long since adopted the following method: See that the body is straight and the pelvis 
(i. e. the line between the two spines) at right angles to it. Let an assistant hold the 
head immovably in the middle line. Let the patient seize the tape-line with his teeth. 
Measure one side, say to the inner malleolus. Then measure the other side-never by 
keeping the measure of the first side and simply passing across to the other leg, but by 
an independent measurement. The last precaution eliminates our preconceptions. The 
chief source of error here-which exists in all methods of measurement-is the position 
of the pelvis. The advantage is in one and the same starting-point, and that in the 
median line. 
It must not be forgotten, however, that there is not infrequently a normal difference 
in the length of the two legs.] 
69. Spine of the Pubes.-The spine of the pubes is the best guide to the external 
abdominal ring, which cannot easily be felt by placing the finger directly over it, since it 
is generally covered by fat. To feel it distinctly we should push up the skin of the 
scrotum and get beneath the subcutaneous fat. If there be any difficulty in finding it, 
abduct the thigh, and the tense tendon of the adductoi- longus will lead up to it. 
The position of the spine of the pubes is appealed to as a means of diagnosis in doubt 
between inguinal and femoral hernia. The spine lies on the outer side of the neck of an 
inguinal hernia, on the inner side of the neck of a femoral. 
The spine of the pubes is nearly on the same horizontal line as the upper part of the 
trochanter major. In this line about one full inch external to the spine is the femoral 
ring. Here is the seat of stricture in a femoral hernia. 
70. Poupart's Ligament, or Crural Arch.-The line of Poupart's ligament 
(crural arch) is in most persons indicated by a slight crescent-like furrow along the skin. 
It corresponds with a line drawn, not straight, but with a gentle curve downward, from 
the spine of the ilium to the spine of the pubes. With the help of the preceding land- 
marks it is easy to find the exact position of the external and internal abdominal rings 
and the direction of the inguinal canal. 
[In hernia it is always treacherous to trust the eye. We must define exactly the iliac 
and pubic spines by the fingers, and draw the line of Poupart's ligament between them 
by an aniline pencil. It lies at the uppermost border of the " groin," or groove between 
the abdomen and the thigh; and unless we so define its two ends we are very apt to get 
it, and especially the inner and most important end, too low, and so mistake the variety 
of hernia we have to deal with. 
Moreover, an examination of the external abdominal ring will disclose its condition 
and show whether the hernia is or is not inguinal. Unfortunately, in women, in whom 
femoral hernia is most frequent, this examination is least satisfactory. The exact location 
of the line of Poupart's ligament is, therefore, in women doubly important.] 
71. Abdominal Rings.-The external abdominal ring is situated immediately above 
the spine of the pubes. It is an oval opening with the long axis directed obliquely down- 
ward and inward. Though its size varies a little in different persons, yet as a rule it will 
admit the end of the little finger, so that we can tell by examination whether it be free 
or otherwise. To ascertain this, the best way is to push up the thin skin of the scrotum 
before the finger; then, by tracking the spermatic cord, the finger readily glides over the 
crest of the pubes and feels the sharp margins of the ring. 1044 
LANDMARKS. 
The position of the internal ring is about midway between the spine of the ilium and 
the symphysis of the pubes, and about two-thirds of an inch above Poupart's ligament. 
72. Inguinal Canal.-The position of the external and internal abdominal rings 
being ascertained, it is plain that the direction of the inguinal canal must be obliquely 
downward and inward, and that its length in a well-formed adult male is from one and a 
half to two inches, according as we include the openings or not. In very young children 
the canal is much shorter and less oblique, the inner ring being behind the outer. With 
the growth of the pelvis in its transverse direction the anterior spines of the ilia become 
farther apart, and thus draw the internal ring more and more away from (i. e. to the 
outer side of) the external. 
73. Spermatic Cord.-The spermatic cord can be felt as it emerges through the 
external ring, and its course can be tracked into the scrotum. The vas deferens can be 
distinctly felt at the back of the cord and separated from its other component parts. 
74. Epigastric Artery.-The direction of the deep epigastric artery corresponds 
with a line drawn from the inner border of the internal ring up the middle of the Rectus 
muscle toward the chest. [It lies to the inside of oblique, and to the outside of direct, 
inguinal hernia.] 
In thin persons the absorbent glands which lie along Poupart's ligament can be dis- 
tinctly felt. They are usually oval, with their long axes parallel to the line of the 
ligament. [See § 97.] 
75. Abdominal Viscera.-Now let us see how far we can make out externally the 
position and size of the abdominal viscera. 
To make this examination with anything like success it is desirable to relax the 
abdominal muscles. The man should be on his back, the head, shoulders, and thorax 
being well raised, to relax the Recti muscles, and the thighs bent on the abdomen, to 
relax the several fasciae attached to the crural arch. To induce complete relaxation 
where a very careful examination is desired [ether or] chloroform should be given. 
In manipulating the abdomen we should not use the tips of the fingers. This is sure 
to excite the contraction of the muscles. The flat hand should be gently pressed upon 
it, and with an undulating movement. 
76. It is well to bear in mind that the central tendon of the Diaphragm is about the 
level of the lower end of the sternum at its junction with the seventh costal cartilage; 
that the right half of the Diaphragm rises to about the level of the fifth rib-that is, 
about an inch below the nipple; that the left half does not rise quite so high. In tran- 
quil breathing the Diaphragm descends about half an inch. 
The position of the abdominal viscera varies, to a certain extent, in different persons. 
In some of them, especially the stomach, their position varies in the same person at 
different times. 
Let us take first the largest of the abdominal viscera-the liver. 
77. Liver.-The liver lies under the right hypochondrium, and passes across the 
middle line over the stomach into the left hypochondrium, generally speaking as far as 
the left mammary line. The extent to which it can be felt below the edges of the ribs 
depends upon whether it is enlarged or not, as well as upon its texture, and also upon 
the amount of flatus in the stomach and intestines. As a rule, in health its lower thin 
border projects about half an inch below the costal cartilages, and can be felt moving up 
and down with the action of the Diaphragm, but it requires an educated hand to feel it: 
an uneducated hand would miss it altogether. That part of it, however, which crosses 
the middle line below the ensiform cartilage is much more accessible to the feel; here it 
lies immediately behind the linea alba and in front of the stomach, nearly halfway down 
to the umbilicus. Here, therefore, is the best place to feel whether the livei' be enlarged 
or pushed down lower than it ought to be. If it be much enlarged and much lowrnr, 
even the most untutored hand could detect its edge. 
Even if the edge of the liver be felt very much lower than its normal below the ribs, 
it does not necessarily follow that the liver is enlarged, since it may be pressed down by 
other causes-for instance, the habit of wearing tight stays. 
To what height does the liver ascend ? This can only be ascertained by careful per- 
cussion of the chest-wall. The highest part of its convexity on the right side is about 
one inch below the nipple, or nearly on a level with the external and inferior angle of the 
pectoralis major. Posteriorly, the liver comes to the surface below the base of the right 
lung, above the level of the tenth dorsal spine. 
Roughly speaking, the upper border of the liver corresponds with the level of the 
tendinous centre of the Diaphragm; that is, the level of the lower end of the sternum. THE ABDOMEN. 
1045 
Thus, a needle thrust into the right side, between the sixth and seventh ribs, would 
traverse the lung and then go through the Diaphragm into the liver. 
78. Gall-bladder.-The gall-bladder, or rather the fundus of it, is situated just 
below the edge of the liver, about the ninth costal cartilage, outside the edge of the 
right Rectus muscle, but [unless distended] cannot be felt. 
79. Stomach.-The stomach varies in size more than any [other] organ in the body. 
When empty and contracted (63) it lies at the back of the abdomen, overlapped by the 
left lobe of the liver, and in front of the pancreas. When very full, it turns on its axis 
and swells up toward the front, coming close behind the wall of the abdomen, occupying 
most of the left hypochondrium and epigastrium, displacing the other contiguous organs, 
pushing in every direction, and often interfering with the action of the heart and left 
lung. Hence the palpitation and distressing heart symptoms in indigestion and flatu- 
lence. 
The cardiac orifice of the stomach lies to the left of the middle line, just below the 
level of the junction of the seventh costal cartilage with the sternum. 
80. Pylorus.-The pylorus lies under the liver, on the right side, near the end of 
the cartilage of the eighth rib, but it cannot be felt, unless occasionally when enlarged 
and hardened by disease. 
81. Spleen.-The spleen, if it be healthy, cannot be felt, so completely is it shel- 
tered by the ribs. It lies on the left side, connected to the great end of the stomach, 
beneath the ninth, tenth, and eleventh ribs, between the axillary lines-lines drawn ver- 
tically downward from the anterior and posterior margins of the axilla. Its upper edge 
is on a level with the spine of the ninth dorsal vertebra, its lower with the spine of the 
eleventh. 
Its position and size, therefore, in health can only be ascertained, and not very accu- 
rately, by the extent of dulness on percussion. The greatest amount of dulness would 
be over the tenth and eleventh ribs; above this the thin edge of the lung would inter- 
vene between the spleen and the abdominal wall. If, therefore, the spleen can be dis- 
tinctly felt below the ribs, it must be enlarged. In proportion to its enlargement, so can 
its lower rounded border be detected below the tenth and eleventh ribs, especially when 
forced downward by a deep inspiration.1 
82. Pancreas.-The pancreas lies transversely behind the stomach, and crosses the 
aorta and the spine about the junction of the first and second lumbar vertebrae. The 
proper place to feel for it, therefore, would be in the linea alba, about two or three inches 
above the umbilicus. Is it perceptible to the touch ? Only under very deep pressure 
and very favorable circumstances, such as an emaciated and empty abdomen. It is 
worth remembering that it may be felt under such conditions. The pancreas of normal 
size, in thin persons, has been mistaken for disease-disease of the transverse arch of 
the colon or aneurism of the abdominal aorta. 
83. Kidney.-The kidney lies at the back of the abdomen, on the Quadratus lum- 
borum and Psoas muscles, opposite the two lower dorsal and two upper lumbar spines. 
The right, owing to the size of the liver, is a trifle-say, three-quarters of an inch- 
lower than the left. The pelvis of the kidney is on about the level of the spine of the 
first lumbar vertebrae: the upper border is on about the level of the space between the 
eleventh and twelfth dorsal spines; the lower border comes as low as the third lumbar 
spine. During a deep inspiration both kidneys are depressed by the Diaphragm nearly 
half an inch. 
Can we feel the normal kidney ? The only place where it is accessible to pressure is 
just below the last rib, on the outer edge of the Erector spinae. I say accessible to 
pressure, for I have never succeeded in satisfying myself that I have distinctly felt its 
rounded lower border' in the living subject, nor even in the dead, with the advantage of 
flaccid abdominal walls and the opportunity of making hard pressure with both hands 
placed simultaneously, one in front of the abdomen, the other on the back. For these 
reasons, although we can easily ascertain its degree of tenderness, we cannot actually 
feel it unless it be considerably enlarged. 
We must be on our guard not to mistake for the kidney an enlarged liver or spleen 
or an accumulation of feces in the lumbar part of the colon. [As Sir William Jenner 
has pointed out, the anterior border of the spleen is sharp and may be notched, in both 
of which respects it differs from the kidney, even when enlarged.] 
84. Large Intestine.-Let us now trace the large intestine and see where it is 
1 See some good observations on the position of the enlarged spleen, by Sir W. Jenner, Brit. Med. 
Journ., Jan. 16, 1869. 1046 
LANDMARKS. 
accessible to pressure. The caecum or caput coli and the ilio-caecal valve lie in the right 
iliac fossa [or more frequently in the upper pelvis, much nearer the middle line than gen- 
erally supposed1]. The ascending colon runs up the right lumbar region over the right 
kidney. [For its line, see § 51.] The transverse colon crosses the abdomen two or three 
inches above the umbilicus. The descending colon lies in the left lumbar region in front 
of the left kidney. The sigmoid flexure occupies the left iliac fossa. 
Throughout this tortuous course, except at the hepatic and splenic flexures, the colon 
is accessible to pressure, and we could, under favorable circumstances, detect hardened 
feces in it. In a case which occurred in St. Bartholomew's Hospital a collection of feces 
in the transverse colon formed a distinct tumor in the abdomen. All the symptoms 
yielded to large and repeated'injections of olive oil. In another case an accumulation 
of fecal matter in the sigmoid flexure during life was mistaken for a malignant disease. 
85. Colotomy.-The operation of opening the colon (colotomy) may be done in 
the right or left loin below the kidney, in that part of the colon not covered by 
peritoneum. 
The landmarks of the operation are: (1) the last rib, of which feel the sloping edge; 
(2) the crest of the ilium ; (3) the outer border of the Erector spinas. The incision 
should be about three inches long, midway between the rib and the ilium. It should 
begin at the outer border of the Erector spinae, and should slope downward and outward 
in the direction of the rib. The edge of the Quadratus lumborum, which is the guide 
to the colon, is about one inch external to the edge of the Erector spinae. or three full 
inches from the lumbar spines. The line of the gut is vertical, and runs for a good two 
inches between the lower border of the kidney and the iliac crest on the left side; rather 
less on the right. 
Small Intestines.-All the room below the umbilicus is occupied by the small 
intestines. The coils of the jejunum lie nearer to the umbilicus (one reason of the 
great fatality of umbilical hernias). Those of the ilium are lower down. [As the 
patches of Peyer involved in typhoid fever lie chiefly near the lower end of the ilium, 
which terminates at the ilio-caecal valve, this will account for the tenderness found here. 
It must be remembered that in ascites, while the fluid will gravitate to the lowest 
point in the abdominal cavity, the intestines, being filled with air and tethered to the 
spine by the mesentery, will float on top. Hence the value of "postural diagnosis"- 
i. e. percussion in different postures, on the right side, the left side, the back, etc. In any 
solid or encysted tumor this cannot hold good.] 
On the right side, a little below the ninth rib, the colon lies close to the gall-bladder, 
and is, after death, sometimes tinged with bile. Posteriorly, this part of the colon is in 
contact with the kidney and duodenum. 
86. Bladder.-When the bladder distends it gradually rises out of the pelvis into 
the abdomen, pushes the small intestines out of the way [lifts the peritoneum off from 
its anterior wall], and forms a swelling above the pubes, reaching in some instances up 
to the navel. The outline of this swelling is perceptible to the hand as well as to per- 
cussion. More than this, fluctuation can be felt through the distended bladder by tap- 
ping on it in front with the fingers of one hand, while the forefinger of the other passed 
up the rectum feels the bottom of the trigone. 
THE PERINEUM. 
The body is supposed to be placed in the usual position for lithotomy. 
87. Bony Framework.-We can readily feel the osseous and ligamentous bound- 
aries of the perineum-namely, the rami of the pubes and ischia, the tuberosities of the 
ischia, the great sacro-ischiatic ligaments, and the apex of the coccyx. This framework 
forms a lozenge-shaped space. If we draw an imaginary line across it from the front of 
one tuber ischii to the other, we divide this space into an anterior and a posterior triangle. 
The anterior is nearly equilateral, and in a well-formed pelvis its sides are from three to 
three and a half inches long. It is called the urethral triangle. The posterior, contain- 
ing the greater part of the anus and the ischio-rectal fossa on each side, is called the 
anal triangle. 
88. Raphe.-A slight central ridge of skin, called the "raphe," runs from the anus 
up the perineum, scrotum, and penis. This raphe, or middle line of the perineum, is the 
1 See Mi'. Treves's valuable monograph on The Anatomy of the Intestinal Canal and Peritoneum in 
Man. THE PERINEUM. 
1047 
"line of safety" in making incisions to let out matter or effused urine or to divide a 
stricture. 
89. Central Point of the Perineum.-It is very important to know that a point 
of the raphe about midway between the scrotum (where it joins the perineum) and the 
centre of the anus corresponds with the so-called " central tendon," where the perineal 
muscles meet. The bulb of the urethra lies above this point, and never, at any age, 
comes lower down. The artery of the bulb, too, never runs below this level. Therefore 
the incision in lithotomy should never commence above it. A knife introduced at this 
point and pushed backward with a very slight inclination upward would enter the mem- 
branous part of the urethra just in front of the prostate gland; pushed still farther, it 
would enter the neck of the bladder. This point, then, is a very good landmark to the 
urethra in lithotomy, or, indeed, in any operations on the perineum. 
The incision in the lateral operation of lithotomy, beginning below the point indi- 
cated, should be carried downward and outward between the anus and the tuberosity of 
the ischium, a little nearer to the tuberosity than the anus [because the rectum is wider 
than the anus]. The lower end of the incision should reach a point just below the [level 
of the] anus. 
90. Triangular Ligament.-In a thin perineum we can feel the lower border of 
the deep perineal fascia, or the so-called " triangular ligament," of the urethra. The 
urethra passes through it about one inch below the lower part of the symphysis pubis 
and about three-quarters of an inch higher than the central tendon of the perineum. It 
is important to bear in mind these landmarks in introducing a catheter. If the catheter 
be depressed too soon, its passage will be resisted by the triangular ligament; if too late, 
it will be likely to make a false passage by running through the bulb. 
91. Anus.-One of the most important landmarks which guide a surgeon in his 
operation about the anus is a white line1 at the junction of the skin and mucous mem- 
brane. It is easily recognized and is of especial interest, because it marks with great 
precision the linear interval between the External and Internal sphincter muscles. From 
this line the Internal sphincter extends upward, beneath the mucous membrane, for about 
an inch, becoming gradually more and more attenuated. 
The wrinkled appearance of the anus is caused by the contraction of the External 
sphincter. At the bottom of these cutaneous folds, especially toward the coccyx, we 
look for " fissure of the anus." 
92. Landmarks in the Rectum.-Many valuable landmarks may be felt by intro- 
ducing the finger into the rectum, with a catheter at the same time in the urethra. The 
principal of these landmarks are the following: 
a. The finger can feel the extent and powerful grasp of the Internal sphincter for 
about one inch up the bowel (91). 
b. Urethra.-Through the front wall of the bowel it can most distinctly feel the 
track of the membranous part of the urethra, exactly in the middle line. This is very 
important, because you can ascertain with precision whether the catheter has deviated 
from the proper track. 
c. Prostate Gland.-About an inch and a half or two inches from the anus the fin- 
ger comes upon the prostate gland. The gland lies in close contact with the bowel, and 
can be detected by its shape and hard feel. The finger, moved from side to side, can 
examine the size of its lateral lobes, their consistence and sensibility. 
d. The finger, introduced still farther, can reach beyond the prostate as far as the apex 
of the trigone of the bladder. More than this, it can feel the angle between the ductus 
communes ejaculatorii, which forms the apex of the trigone. This is the precise spot 
where the distended bladder should be punctured through the rectum. The more dis- 
tended the bladder, the easier can this spot be felt. Fluctuation is at once detected by a 
gentle tap on the bladder above the pubes (86). The trocar must be thrust in the direc- 
tion of the axis of the distended bladder; that is, roughly speaking, in a line drawn from 
the anus through the pelvis to the umbilicus. 
e. The fold of peritoneum called the recto-vesical pouch is about four inches from 
the anus, therefore it is not within reach of the finger, and we run no risk of wounding it 
in tapping the bladder if the trocar be introduced near the angle of the trigone. [J. B. 
Roberts has measured the distance of the recto-vesica] (or recto-vaginal) pouch from the 
anus, both in situ and after removal from the body. The distance was one and a quarter 
to two inches in situ, and from three and a half to four and a quarter inches after removal.] 
f. The finger can feel one of the ridges or folds of mucous membrane which are situ- 
1 Lectures on Rest and Pain, by John Hilton, F. K. S., London, 1863, p. 280. 1048 
LANDMARKS. 
ated at the lower part of the rectum. This fold projects from the side, and sometimes 
from the upper part of the rectum, near the prostate. When thickened or ulcerated this 
fold occasions .great pain in defecation, and great relief is afforded by its division. 
g. Lastly, the finger can examine the condition of the spaces filled with fat on either 
side of the rectum, called the ischio-rectal fossae, with a view to ascertain the existence of 
deep-seated collections of matter or the internal communications of fistulse. 
[It is often important to instruct mothers and nurses as to the difference in the 
Direction of the Anus and that of the Rectum, in order that they may introduce 
the nozzle of an enema syringe without pain. The rectum, after following the curve of 
the sacrum and coccyx, suddenly bends backward and terminates in the anus. The axis 
of the anal opening is in the direction of the navel for about an inch, and when the finger, 
the syringe-nozzle, or other instrument has been introduced thus far, it may then be swept 
around so as to point to the small of the back and be pushed in as far as necessary. 
It is useful to remember that in women the posterior wall of the vagina can be everted 
from the rectum, and, vice versa, the rectum from the vagina, and so be carefully exam- 
ined without a speculum.] 
Introduction of Catheters.-In the introduction of catheters the following are 
good rules: Keep the point of the instrument well applied against the upper surface of 
the urethra ; depress the handle at the right moment (90) ; keep the umbilicus in view ; 
in cases of difficulty feel the urethra through the rectum, to ascertain whether the instru- 
ment be in the right direction. Attention to these rules diminishes the risk of making a 
false passage, an injury which under great delicacy in manipulation ought never to 
happen. 
Urethra in the Child.-In children the membranous part of the urethra is, rela- 
tively speaking, very long, owing to the smallness of the prostate. It is also more 
sharply curved, because the bladder in children is more in the abdomen than in the 
pelvis. It is, moreover, composed of thin and delicate walls. The greatest gentleness, 
therefore, should be used in passing a catheter, else the instrument is likely to pass 
through the coats and make a false passage. Hence the advantage of being able to 
ascertain through the rectum whether the instrument be in the right track and moving 
freely in the bladder, which can also be easily felt in children. 
THE THIGH. 
93. Poupart's Ligament, or Crural Arch.-Mark the anterior superior spine of 
the ilium, the spine of the pubes, and define the line of Poupart's ligament, which extends 
between them. This line is one of our guides in the diagnosis of inguinal and femoral her- 
nise. If the bulk of the tumor be above the line, the hernia is probably inguinal; if below 
it, femoral. The line is not a straight one drawn from the spine of the ilium to the spine 
of the pubes, but slightly curved, with the convexity downward, owing to its close con- 
nection with the fascia lata of the thigh. In many persons it can be distinctly felt; in 
nearly all its precise course is indicated by a slight furrow in the skin. 
For the points about the spine of the pubes refer to paragraph 69. 
94. Furrow at the Bend of the Thigh.-When the thigh is even slightly bent 
there appears a second furrow in the skin below that at the crural arch. This second 
furrow begins at the angle between the scrotum and the thigh, passes outward, and is 
gradually lost between the top of the trochanter and the anterior superior spine of the 
ilium. It runs right across the front of the capsule of the hip-joint. For this reason it 
is a valuable landmark in amputation at the hip-joint. The point of the knife should be 
introduced externally where the furrow begins, should run precisely along the line of it, 
and come out where it ends, so that the capsule of the joint may be opened with the first 
thrust. In suspected disease of the hip, pressure made in this line, just below the spine 
of the ilium, will tell us if the joint be tender. Effusion into the joint obliterates all 
trace of the furrow and makes a fulness when contrasted with the opposite groin. 
95. Saphenous Opening.-In most persons there is a natural depression over the 
saphenous opening in the fascia lata, where the saphena vein joins the femoral. The 
position of this opening is just below the inner third of Poupart's ligament and about an 
inch and a half external to the spine of the pubes. This is the place where the swelling 
of a femoral hernia first appears; therefore it ought to be carefully examined in cases of 
doubt. 
96. Femoral Ring.-The position of the femoral ring, through which the hernia THE THIGH. 
1049 
escapes from the abdomen, is, on a deeper plane, about half an inch higher than the 
saphenous opening and immediately under Poupart's ligament. As the plane of the 
ring is vertical in the supine position of the body, the way in which we should try to 
reduce a femoral hernia is by pressure, applied first in a downward direction, afterward 
in an upward. The intestine protruded has to pass back under a sharp edge of fascia- 
namely, the upper horn of the saphenous opening (known as Hey's ligament) [or the fal- 
ciform process]. At the same time we bend the thigh, to relax the fascia as much as 
possible. 
A good way to find the seat of the femoral ring with precision is the following: Feel 
for the pulsation of the femoral artery on the pubes ; allow half an inch (on the inner 
side) for the femoral vein ; then comes the femoral ring. 
In performing the operation for the relief of the stricture in femoral hernia the incis- 
ion through the skin should be about an inch and a half external to the spine of the 
pubes. Its direction should be vertical and its middle should be just over the femoral 
ring. 
97. Lymphatic Glands in the Groin.-The cluster of inguinal and femoral [i. e. 
saphenous] lymphatic glands can sometimes be felt in thin persons. The inguinal lie 
for the most part along the line of Poupart's ligament: they receive the absorbents from 
the wall of the abdomen, the urethra, the penis, the scrotum, anus [perineum, and glu- 
teal region]. The femoral [or saphenous] glands lie chiefly over the saphenous opening 
and along the outer side of the saphena vein : they receive the absorbents of the lower 
extremity; they receive some also from the scrotum, of which we have practical evi- 
dence in cases of chimney-sweepers' cancer. [It is extremely important to differentiate 
these two sets of glands-the inguinal and the saphenous-as the enlargement of one 
set or the other often throws great light on the seat and character of any lesion pro- 
ducing this enlargement.] 
98. Trochanter Major.-The trochanter major is a most valuable landmark, to 
which we are continually appealing in injuries and diseases of the lower extremity. 
There is a natural depression over the hip (in fat persons) [and thin too], where it lies 
very near the surface, and can be plainly felt, especially when the thigh is rotated. 
Nothing intervenes between the bone and the skin except the strong fascia of the Gluteus 
maximus and the great bursa underneath it. 
The top of the trochanter lies pretty nearly on a level with the spine of the pubes, and 
is about three-fourths of an inch lower than the top of the head of the femur. A careful 
examination of the bearing of the great trochanter to the other bony prominences of the 
pelvis, and a comparison of its relative position with that of the opposite side, are the best 
guides in the diagnosis of injuries about the hip and the position of the head of the femur. 
99. Nelaton's Line.-" If in the normal state you examine the relations of the 
great trochanter to the other bony prominences of the pelvis, you will find that the top 
of the trochanter corresponds to a line drawn from the anterior superior spine of the 
ilium to the most prominent part of the tuberosity of the ischium. This line also runs 
through the centre of the acetabulum. The extent of displacement in dislocation or frac- 
ture is marked by the projection of the trochanter behind and above this line."1 
" Nelaton's line," as it is termed, theoretically holds good. But in stout persons it is 
not always easy to feel these bony points so as to draw the line with precision. A sur- 
geon must, after all, in many cases trust to measurement by his eyes and his flat hands- 
his best guides. Thus, let the thumbs be placed firmly on the spines of the ilia, while 
the fingers grasp the trochanters on each side. Having the sound side as a standard of 
comparison, the hand will easily detect any displacement on the injured side. Hippoc- 
rates bids us compare the sound parts with the parts affected (in fractures) and observe 
the inequalities. 
The top of the great trochanter is the guide in an operation recently introduced by 
Mr. Adams-namely, the " subcutaneous section of the neck of the femur." " The punc- 
ture should be made one inch above and nearly one inch in front of the top of the tro- 
chanter. The neck of the bone is to be sawn through at right angles to its axis, the saw 
working parallel to Poupart's ligament and about one inch below it." [Gant's operation 
is a similar subcutaneous section of the shaft of the femur just below the lesser trochanter.] 
Spine of the Ilium.-The anterior superior spine of the ilium is the point from 
which we measure the length of the lower limb. [See § 68.] By looking at the spines 
of opposite sides we can detect any slant in the pelvis. [Their position should be care- 
fully marked by an aniline pencil.] By pressure on both spines simultaneously [or, better 
1 Nelaton, Pathologic chirurgicale, t. iv. p. 441,1848. 1050 
LANDMARKS. 
still, by grasping this portion of the ilium] we examine if there be a fracture of the pelvis 
or disease at the sacro-iliac joint. 
100. " In reducing a dislocation of the hip by manipulation it is important to bear in 
mind that in every position the head of the femur faces nearly in the direction of the inner 
aspect of its internal condyle." 1 
101. Compression of Femoral Artery.-About a point midway between the 
spine of the ilium and the symphysis pubis the femoral artery can be felt beating and 
effectually compressed against the pubes. How should the pressure be applied when the 
patient lies on the back ? In accordance with the slope of the bone ; that is, with a slight 
inclination upward. A want of attention to this point is the reason why so many fail 
when they undertake to command the circulation through the femoral artery in an ampu- 
tation or to cure an aneurism by digital compression. [I think the chief reason of failure 
in attempting compression of the femoral is that pressure is made two or three inches 
below Poupart's ligament, instead of immediately below it. In the former position thick 
muscles form the floor against which it is ineffectually compressed; in the latter it is 
directly on the edge of the pelvis or the head of the femur.] 
If the Italian tourniquet be used, we should be careful to adjust the counterpad well 
under the tuberosity of the ischium. If digital pressure be used, it is easy to command 
the femoral by slight pressure of the thumb, provided the fingers have a firm hold on the 
great trochanter. 
102. Sartorius.-The Sartorius is the great fleshy landmark of the thigh, as the 
Biceps is of the arm and the Sterno-cleido-mastoideus of the neck. Its direction and 
borders may easily be traced by asking the patient to raise his leg, a movement which 
puts the muscle in action. The same action defines the boundaries of the triangle (of 
Scarpa) formed by Poupart's ligament, the Adductor longus, and Sartorius. 
Line of Femoral Artery.-To define the course of the femoral artery draw a line 
from midway between the anterior superior spine of the ilium and the symphysis pubis to 
the (spur-like) tubercle for the Adductor magnus on the inner side of the knee. The 
femoral artery lies under the upper two-thirds of this line. 
The Sartorius begins to cross the artery, as a rule, from three to four inches below 
Poupart's ligament. The point at which the profunda artery arises is about one and a half 
or two inches below the ligament. Therefore the incision for tying the femoral in 
Scarpa's triangle should commence about a hand's breadth below Poupart's ligament 
[unless this is actually measured, we are very apt to get the incision too low down], 
and be continued for three inches in the line of the artery. 
To command the femoral in Scarpa's triangle the pad of the tourniquet should be 
placed at the apex, and the direction of the pressure should be, not backward, but out- 
ward, so that the artery may be compressed against the femur. 
In the middle third of the thigh the femoral artery lies in Hunter's canal, overlapped 
by the Sartorius. About the commencement of the lower third the artery leaves the 
canal through the oval opening in the Adductor magnus, and under the name of popliteal 
enters the popliteal space. The line for finding the artery in Hunter's canal has been 
already traced (102). The incision to reach the artery in this part of its course would 
fall in with the outer border of the Sartorius. 
To command the femoral artery in Hunter's canal the pressure should be directed 
outwardly, so as to press the vessel against the bone. 
THE BUTTOCKS. 
103. Buttocks: Bony Landmarks.-The bony landmarks of the buttocks which 
can be distinctly felt are : 1, the posterior superior spines of the ilia ; 2, the spines of the 
sacral vertebrae; 3, the two tubercles of the last sacral vertebra ; 4, the apex of the coc- 
cyx in the deep groove leading to the anus; 5, the tuberosities of the ischia on each side 
of the anus. 
The posterior spines of the ilia are about the level of the second sacral spine, and cor- 
respond with the middle of the sacro-iliac symphysis [and are marked by a graceful 
dimple]. 
The third sacral spine marks the lowest level to which the membranes of the cord and 
the cerebro-spinal fluid descend in the spinal canal. 
The tuberosities of the ischia, in the erect position, are covered by the Gluteus maxi- 
1 Bigelow, Mechanism of Dislocation and Fracture of the Hip, Philadelphia, 1869. THE KNEE. 
1051 
mus. In the sitting position they support the weight of the body, and are only covered 
by a thick pad of coarse fat. Between this pad and the bones there is a bursa which 
becomes occasionally enlarged and inflamed in coachmen. 
The prominence of the nates is one of the characteristics of man in connection with 
his erect attitude. " Les fesses n'appartiennent qu'a 1'espece humaine." They are formed 
of an accumulation of fat over the great muscle of the buttock (Gluteus maximus). 
From their appearance we may gather some indication of the state of the constitution. 
They are firm and globose in the vigorous, loose and flaccid in the infirm. Wasting and 
flattening of one, compared with the other, is an early symptom of disease in the hip. 
104. Fold of the Buttock.-The deep furrow, termed " the fold of the buttock " 
[or gluteo-femoral crease], which separates the nates from the back of the thigh cor- 
responds with the lower border of the Gluteus maximus. Its altered direction in disease 
of the hip is very characteristic. This is the best place to feel for the great ischiatic 
nerve. We find it by pressing deeply between the trochanter and the tuber ischii, rather 
nearer to the latter. When we sit upright the nerve is not liable to pressure, but it 
becomes numbed when we sit long sideways. 
105. Gluteal Artery.-To find at what point the gluteal artery conies out of the 
pelvis, draw a line from the posterior superior spine of the ilium to the top of the trochanter 
major, rotated inward. The junction of the inner with the middle third of this line lies 
over the artery as it emerges from the upper border of the great ischiatic notch. 
The point of exit of the ischiatic artery from the pelvis is about half an inch lower 
than that of the gluteal. 
106. Pudic Artery.-The pudic artery crosses the spine of the ischium. To find 
it, draw a line from the outer side of the tuber ischii to the posterior superior spine of 
the ilium. The junction of the lower with the middle third gives the position of the 
artery. The ischiatic artery lies close to it, but nearer the middle line. 
Looking at the course of these arteries, it appears that when we sit on hard seats the 
pressure is sustained by the bones; when we recline on soft seats the pressure is sus- 
tained more by the soft parts and reaches the arteries; hence the tendency of modern 
modes of reposing to drive the blood into the interior of the pelvis and favor the pro- 
duction of piles and uterine disorders. A celebrated French accoucheur used to say that 
the fashion of high waists, tight lacing, and easy-chairs brought him many thousands a 
year. 
107. Bony Points.-The patella, the tuberosities of the two condyles, the tubercle 
of the tibia for the attachment of the ligamentum patellae, another (the lateral) tubercle 
on the outer side of the head of the tibia, and the head of the fibula are the chief bony 
landmarks of the knee. 
Observe that the head of the fibula lies at the outer and back part of the tibia, and 
that it is pretty nearly on a level with the tubercle for the attachment of the ligamentum 
patellae. 
We can also feel the adductor tubercle or spur-like projection of bone above the 
internal condyle which gives attachment to the tendon of the Adductor magnus. This 
spur-like projection corresponds with the level of the epiphysis of the lower end of the 
femur, and also with the level of the highest part of the trochlea for the patella-facts 
worth notice in performing excision of the knee. [The importance of preserving intact 
this inferior epiphysial cartilage of the femur is best understood when it is remembered 
that, due to its late ossification, this is the seat of the greatest growth in the entire body. 
While the whole body from birth to adult life grows (in the male) 3.37 times, and the 
whole leg 4.49 times, the lower femur grows 7.30 times.] 
" In reducing a dislocation of the hip it is important to bear in mind that the inner 
aspect of the internal condyle in every position of the limb faces nearly in the direction 
of the head of the femur " (100). 
The tubercle on the outer side of the head of the tibia gives attachment to the broad 
and strong aponeurosis (tendon of the Tensor fasciae), which, acting like a brace for the 
support of the pelvis, is well seen in emaciated persons down the outer side of the thigh. 
[In fracture of the neck of the femur, therefore, instead of being tense, the fascia will 
yield to pressure, especially just above the knee and the great trochanter. The patient 
should be standing (Allis).] This tubercle indicates the level to which the condyles of 
the femur descend, and the lower level of the synovial membrane. 
THE KNEE. 1052 
LANDMARKS. 
The patella in extension of the knee is nearly all above the condyles; in flexion it 
lies in the intercondyloid fossa (more on the external condyle), and thus protects the joint 
in kneeling. Its inner border is thicker and more prominent than the outer, which slopes 
down toward its condyle. 
108. Ligamentum Patellae.--The line of the ligamentum patellae is vertical. 
Hence any deviation from this line one way or the other indicates more or less disloca- 
tion of the tibia. There is a pellet of fat under the ligament which answers a " pack- 
ing " purpose-sinking in when the knee is bent, rising when the knee is extended, and 
bulging on either side of the tendon almost enough to give the feel of fluctuation. 
In a well-formed leg the ligamentum patellae, the tubercle of the tibia, and the middle 
of the ankle should be in the same straight line-a useful point in the adjustment of 
fractures. 
Behind the upper half of the ligamentum patellae is the synovial membrane of the 
knee-joint; behind the lower half is a synovial bursa and a pad of fat. It is well to 
remember this in cases of injury to the ligamentum patellae. 
109. Prepatellar Bursa.-The patellar or housemaid's bursa is situated not only 
over the patella, but over the upper part of the ligament. This is plain enough when 
the bursa becomes enlarged. There is another subcutaneous bursa over the insertion of 
the ligament into the tubercle of the tibia. This is quite independent of the deep bursa 
between the tendon and the bone [the " subpatellar " bursa]. 
110. Synovial Membrane of Knee.-The synovial membrane of the knee when 
the joint is extended rises like a cul-de-sac above the upper border of the patella about 
two inches. It ascends, too, a little higher under the vastus internus than the vastus 
externus-a fact very manifest when the joint is distended. When the knee is bent this 
cul-de-sac is drawn down ; hence the rule of bending the knee in operations near the 
lower end of the femur. 
The lower level of the synovial membrane of the knee is just above the level of the 
upper part of the head of the fibula. The tibio-fibular synovial membrane is, with rare 
exceptions, independent of that of the knee. 
[It is surprising to note what a large part of the surface of the joint, and especially 
on the femur, is exposed to examination by the touch with the knee in flexion. The 
condition of the synovial membrane and the cartilage, therefore, can be ascertained. The 
trochlear groove is especially well defined.] 
111. Popliteal Tendons.-The tendons forming the boundaries of the popliteal 
space can be distinctly felt when the muscles which bend the knee are acting. On the 
outer side we have the biceps running down to the head of the .fibula. On the inner 
side we feel three tendons, disposed as follows: Nearest to the middle of the popliteal 
space is the Semitendinosus [slender], very salient, and traceable high up the thigh; next 
conies the thick round tendon of the Semimembranosus; still more internally is the 
Gracilis. The Sartorius, which forms a graceful muscular prominence on the inner side 
of the knee, does not become tendinous until it gets below it. 
[A very interesting experiment may be tried on the "ligamentous action" (as Prof. 
Cleland calls it) of these muscles. Standing with the back fixed against a wall to steady 
especially the pelvis, the knee can be made almost to touch the belly. But note that the 
knee is flexed. Repeat the experiment, the knee being kept rigid, and when the heel 
has been but slightly raised a sharp pain in the ham follows any effort to carry it higher. 
Flexion of the rigid leg from the vertical line to a right angle increases the distance 
from the tuber ischii to the tuberosities of the tibia by some six or fcight centimeters-an 
amount of stretching these muscles cannot undergo. Hence the compulsory flexion of 
the knee in flexion of the hip. 
The same thing is seen in the wrist. Flex the wrist with the fingers extended, and 
again with the fingers in a " fist." The first movement can be carried to 90°, the second 
only to 30°, or in some up to 60°. Making a fist had already stretched the extensors, 
and they can be stretched but little farther. Many surgeons make errors in the leg, but 
especially in the forearm and hand, and inflict injury as well as needless pain, by forgetting 
these facts while making passive movement. 
It must be noted, however, that in children there is less danger of this over-stretch- 
ing, for from childhood to old age there is a progressive invasion of the extensible belly 
by the inextensible tendon in the muscles generally. Hence the ease with which chil- 
dren, even when seated, can lift the heel (without moving the pelvis) and make the hips 
the point of an acute angle.] 
112. Popliteal Bursa.-The precise position of this bursa in the popliteal space, THE LEG AND ANKLE. 
1053 
which sometimes enlarges to the size of a hen's egg, is between the tendon of the inner 
head of the Gastrocnemius and the tendon of the Semimembranosus, just where they 
rub one against the other. The bursa is from one and a half to two inches long. When 
enlarged it makes a swelling on the inner side of the popliteal space which bulges and 
becomes tense when the knee is extended, and vice versa. I examined one hundred and 
fifty bodies with a view to ascertain how often this bursa communicates with the synovial 
membrane of the knee. There was a communication about once in five instances. This 
should make us cautious in interfering too roughly with the bursa when enlarged. 
113. Popliteal Artery.-The popliteal artery can be felt beating, and can be com- 
pressed against the back of the femur, close to which it lies. But pressure sufficient to 
stop the blood should be firm, and should be made against the bone nearer to the inner 
than the outer hamstrings. The line of the artery corresponds with the middle of the 
ham. It lies under cover of the fleshy belly of the Semimembranosus, and the outer 
border of this muscle is the guide to it. An incision down the middle of the ham would 
fall in with the vessel just above the condyles. 
114. Peroneal Nerve.-The peroneal nerve runs parallel with and close to the 
inner border of the tendon of the Biceps. It can be felt in thin persons. There is 
a risk of dividing it in tenotomy of the Biceps, unless the knife be carefully introduced 
[flatwise between the two and the cut made] from within outward. Below the knee the 
nerve can be felt close to the fibula just below the head, and when pressed upon in this 
situation causes a sensation to run down its branches to the foot. 
115. Bony Points.-The tubercle of the tibia (for the attachment of the ligamentum 
patellae), the sharp front edge called the shin, and the broad flat [internal] subcutaneous 
surface of the bone can be felt all the way down. The inner edge can be felt too, but 
not so plainly. The lower third is the narrowest part of the bone and the most frequent 
seat of fracture. 
The head of the fibula is a good landmark on the outer side of the leg, about one 
inch below the top of the tibia and nearly on a level with the tubercle. Observe that it 
is placed well back, and that it forms no part of the knee-joint and takes no share in sup- 
porting the weight. 
The shaft of the fibula arches backward, the reverse of the shaft of the tibia. The 
fact of the bones not being on the same plane should be remembered in flap amputations. 
The shaft of the fibula is so buried amongst the muscles that the only part to be dis- 
tinctly felt is the lower fourth. Here there is a flat triangular subcutaneous surface 
between the Peroneus tertius in front and the two Peronei (longus and brevis) behind. 
Here is the most frequent seat of fracture. 
116. Malleoli.-The shape and relative position of the malleoli should be carefully 
studied as the great landmarks of the ankle. The inner malleolus does not descend so 
low as the outer, and advances more to the front: at the same time, owing to its greater 
antero-posterior depth, it is on the same plane as the outer behind. The lower border of 
the inner malleolus is somewhat rounded, and the slight notch in it for the attachment 
of the lateral ligament can be felt. The outer malleolus descends lowei' than the inner, 
thus effectually locking the joint on the outer side. Its shape is not unlike the head of 
a serpent. Viewed in profile, it lies just in the middle of the joint. 
In Syme's amputation of the foot at the ankle the line of the incision should run from 
the apex of the outer malleolus, under the sole, to the centre of the inner. 
In a well-formed leg the inner edge of the patella, the inner ankle, and the inner side 
of the great toe should be in the same vertical plane. Look to these landmarks in adjust- 
ing a fracture or dislocation, keeping at the same time an eye upon the conformation of 
the opposite limb. 
[In consequence of violence, usually a sprain, a sliver of the internal surface of the 
thick malleoli may be broken off, seriously implicating the joint, but yet not perceptible 
by mobility, crepitus, or otherwise from the exterior. Mr. Callender has happily named 
such " sprain-fractures." 
Into the intermalleolar space the astragalus is tightly wedged or mortised, and we 
have here, as I pointed out some years ago, a valuable means of diagnosis in case of 
Pott's fracture of the fibula three or four inches above the external malleolus. In such 
a fracture this intermalleolar space is widened. If now the leg be seized by one hand 
THE LEG AND ANKLE. 1054 
LANDMARKS. 
above the ankle and the foot by the other, with the palm under the sole, the thumb and 
fingers will have the astragalus in their grasp. The astragalus can then be pushed side- 
wise against the outer malleolus, and then shoved suddenly toward the firm inner mal- 
leolus, against which it will come with an easily-perceived impact if there be fracture. 
If none exist, the astragalus will have no lateral play. Motion at the medio-tarsal joints 
must not be mistaken for this tibio-tarsal movement.] 
There are several strong tendons to be seen and felt about the ankle. 
117. Tendo Achillis.-Behind is the tendo Achillis. It forms a high relief, with a 
shallow gutter on each side of it. The narrowest part of the tendon, where it should be 
divided in tenotomy, is about the level of the inner ankle; below this it expands again 
to be attached to the lower and back part of the os calcis. Seen in profile, the tendon is 
not straight, but slightly concave, being drawn in by an aponeurosis which forms a sort 
of girdle around it. This girdle proceeds from the posterior ligament of the ankle; and, 
though most of its fibres encircle the tendon, some of them adhere to and draw in its 
sides. All this disappears when the tendon is laid bare by dissection. [Between the 
tendo Achillis and the calcis is a synovial bursa.] 
118. Tendons Behind the Inner Ankle.-Above and behind the malleolus 
internus we can feel the broad flat tendon of the Tibialis posticus, and upon it that 
of the Flexor longus digitorum. The tendon of the Tibialis posticus lies nearest to the 
bone, and comes well up in relief in adduction of the foot. It lies close to, and parallel 
with, the inner edge of the tibia, so that this edge is the best guide to it. Therefore in 
tenotomy the knife should be introduced first perpendicularly between the tendon and 
the bone, and then turned at right angles to cut the tendon. The tendon has a separate 
sheath and synovial membrane, which commences about one inch and a half above the 
apex of the malleolus, and is continued to its insertion into the tubercle of the scaphoid 
bone. The proper place, then, for division of the tendon is about two inches above the 
end of the malleolus. 
In a young and fat child, where the inner edge of the tibia cannot be distinctly felt, 
the best guide to the tendon is a point midway between the front and the back of the 
ankle. An incision in front of this point might injure the internal saphena vein ; behind 
this point, the posterior tibial artery. 
119. Tendons Behind the Outer Ankle.-Behind the malleolus externus we 
feel the two peroneal (long and short) tendons. They lie close to the edge of the fibula, 
the short one nearer to the bone. In dividing these tendons the knife should be intro- 
duced perpendicularly to the surface and about two inches above the apex of the ankle, 
so as to be above the synovial sheaths of the tendons. 
Tendons in Front of the Ankle.-Over the front of the ankle, when the mus- 
cles are in action, we can see and feel, beginning on the inner side, the tendons of the 
Tibialis anticus, the Extensor longus pollicis, the Extensor longus digitorum, and the 
Peroneus tertius. They start up like cords when the foot is raised [especially when 
the action is resisted], and are kept in their proper relative position by strong pulleys 
formed by the anterior annular ligament. Of these pulleys, the strongest is that of the 
Extensor communis digitorum. When the ankle is sprained the pain and swelling arise 
from a stretching of these pulleys and effusion into their synovial sheaths. A laceration 
of one of the pulleys and escape of the tendon is extremely rare. 
The place for the division of the tendon of the Tibialis anticus, so as to divide it 
below its synovial sheath, is about one inch before its insertion into the cuneiform 
bone. The knife should be introduced on the outer side, so as to avoid the dorsal artery 
of the foot. 
[Most of these tendons can be best seen by standing a model on one foot-i. e. in 
unstable equilibrium.] 
Now trace the lines of the arteries and the landmarks near which they divide. 
120. Popliteal Artery.-About one inch and a quarter below the head of the 
fibula-or, say, one inch below the tubercle of the tibia-the popliteal artery divides into 
the anterior and posterior tibial. The peroneal comes off from the posterior tibial about 
three inches below the head of the fibula. 
Consequently, we may lay down, as a general rule, that in amputations one inch 
below the head of the fibula only one main artery, the popliteal, is divided; in amputa- 
tions two inches below the head of the fibula two main arteries, the anterior and posterior 
tibial, are divided; in amputations three inches below the head three main arteries, the 
two tibials and the peroneal, are divided. 
121. Anterior Tibial Artery.-The anterior tibial artery comes in front of the THE FOOT. 
1055 
interosseous membrane one inch and a quarter below the head of the fibula, and here lies 
close to this bone. Its subsequent course is defined by a line drawn from the front of 
the head of the fibula to the middle of the front of the ankle. This line corresponds 
pretty nearly with the outer border of the Tibialis anticus all the way down. If this 
muscle be put in action, its outer border (the intermuscular line) is plainly seen, and the 
incision for the ligature of the artery in any part of its course may be defined with the 
greatest precision. The artery can be felt beating, and can be compressed where it 
crosses the front of the tibia and ankle. 
122. Posterior Tibial Artery.-The posterior tibial commences about one inch 
and a quarter below the head of the fibula. Its subsequent course corresponds with a 
line drawn from the middle of the upper part of the calf to the hollow behind the inner 
ankle, where it can be felt beating distinctly about half an inch behind the edge of the 
tibia. A vertical incision down the middle of the calf would reach the artery under 
cover of the Gastrocnemius and Soleus. A vertical incision along the middle third of 
the leg, about half an inch from the inner edge of the tibia, would enable the operator 
to reach the artery sideways, by detaching from the bone the tibial origin of the 
Soleus. 
[The posterior tibial artery, behind the malleolus, lies midway between the tendo 
Achillis, or the heel, and the malleolus. It is the middle of five structures: in front of 
it are (1) the Tibialis posticus tendon, (2) the Flexor longus digitorum tendon; behind 
it are (4) the posterior tibial nerve and (5) the Flexor longus pollicis tendon. It is 
important to observe that, as Wyeth has shown, it bifurcates into the two plantar arteries 
at a line drawn from the point of the malleolus to the middle of the heel.] 
123. Saphena Veins.-The subcutaneous veins on the dorsum of the foot form an 
arch convex toward the toes (as on the back of the hand), from which issue the two 
main subcutaneous trunks of the lower limb, the internal and external saphena veins. 
The internal vein can be always plainly seen over the front of the inner ankle. Its 
farther course up the inner side of the leg, knee, and thigh to its termination in the 
femoral is not in all persons manifest. 
[It lies about half an inch behind the internal border of the tibia, skirts the knee 
postero-internally, and, passing up the inside of the thigh, empties at the saphenous 
opening into the femoral. A thrombus not uncommonly may form in it or in the 
femoral, or may extend from it into the femoral. The careful investigation of both 
veins then becomes very important, and is not generally difficult, especially if we remem- 
ber the course of the saphena and the relation of the femoral to its artery.] 
The external saphena vein runs behind the outer ankle and up the middle of the calf 
to empty itself (generally) into the popliteal vein. 
THE FOOT. 
What are the bony landmarks which guide us in the surgery of the foot ? 
124. Points of Bone.-Along the inner side of the foot, beginning from behind, 
we can feel-1, the tuberosity of the os calcis ; 2, the projection of the internal malleolus ; 
3, the projection of the os calcis, termed " sustentaculum tali," about one full inch below 
the malleolus ; 4, about one inch in front of the malleolus internus and a little lower is the 
tubercle of the scaphoid bone, the gap between it and the sustentaculum tali being filled 
by the calcaneo-scaphoid ligament and the tendon of the Tibialis posticus, in which there 
is often a sesamoid bone; 5, the internal cuneiform bone; 6, the projection of the first 
metatarsal bone; 7, the sesamoid bones of the great toe. [On a line nearly midway 
from the scaphoid to the inner malleolus the head of the astragalus can be felt. In front, 
with the foot in extension, we can feel also the upper and lateral articular surfaces of the 
astragalus, and especially the ridges between them.] 
Along the outer side of the foot we can feel-1, the external tuberosity of the os 
calcis; 2, the external malleolus; 3, the peroneal tubercle of the os calcis, one inch 
below the malleolus, with the long peroneal tendon below it and the short one above it; 
4, the projection of the base of the fifth metatarsal bone. 
125. Lines of Joints.-In fat persons the following rules for finding the joints may 
be of service as regards the surgery of the foot: 
The level of the ankle-joint lies about half an inch above the end of the inner mal- 
leolus. This is worth remembering in performing " Syme's amputation." 
The tubercle of the scaphoid bone is the best guide to the astragalo-scaphoid joint, 1056 
LANDMARKS. 
which lies immediately behind it, and the plane of this joint is in the same line as that 
of the calcaneo-cuboid. Thus, a line drawn transversely over the dorsum of the foot, 
behind the tubercle of the scaphoid, would strike both the joints opened in " Chopart's 
operation." 
Place your thumb on the tubercle of the scaphoid, and measure about one inch and 
a half in front: here you find the joint between the internal cuneiform bone and the 
metatarsal bone of the great toe. This point is useful in " Lisfranc's operation," which 
consists in the removal of the metatarsal bones. 
The line of the calcaneo-cuboid joint lies midway between the external malleolus and 
the (tarsal) end of the metatarsal bone of the little toe. 
The projection of the fifth metatarsal bone is the guide to the joint between it and 
the cuboid. 
Notice that the line of the joints between the metatarsal bones and the first phalanges 
lies a full inch farther back than the interdigital folds of the skin. This is a point to be 
remembered in amputating the toes. 
126. Dorsal Artery.-The line of the dorsal artery of the foot is from the middle 
of the ankle to the interval between the first and second metatarsal bones. The artery can 
be felt beating over the bones along the outer side of the Extensor proprius pollicis, 
which is the best guide to it. 
127. Bursa.-The synovial sheath of the Extensor proprius pollicis extends from 
the front of the ankle over the instep (apex of the internal cuneiform bone) as far as the 
metatarsal bone of the great toe. There is generally a bursa over the instep above, or it 
may be below, the tendon. 
There is often a large irregular bursa between the tendons of the Extensor longus 
digitorum and the projecting end of the astragalus, over which the tendons play. There 
is much friction here. It is well to be aware that this bursa sometimes communicates 
with the joint of the head of the astragalus. 
128. Plantar Arteries.-The course of the external plantar artery corresponds 
with a line drawn from the hollow behind the inner ankle obliquely across the sole nearly 
to the base of the fifth metatarsal bone; from thence the artery turns transversely across 
the foot, lying (deeply) near the bases of the metatarsal bones, till it inosculates with the 
dorsal artery of the foot in the first interosseous space. 
The course of the internal plantar corresponds with a line drawn from the inner side 
of the os calcis to the middle of the great toe. 
129. Plantar Fascia.-To divide the plantar fascia subcutaneously, the best place 
is about one inch in front of its attachment to-the os calcis. This is the narrowest part 
of it. The knife should be introduced on the inner side, and the incision will be behind 
the plantar artery. 
The subcutaneous section of the tendon of the Abductor pollicis should be made 
about one inch before its insertion. 
[It is evidently the opinion of shoemakers that the axis of the sole of the foot ought 
to be a median straight line, and the two borders symmetrically curved toward it. If a 
foot they have not unduly distorted be observed carefully, it will be seen (B. Lee) that 
the axis is curved; that on the inner border of the foot, the heel and the front part of 
the foot are in nearly a straight line, while the outer border is a curved line. If Nature 
were followed, natural-shaped feet would be the result and the miseries of corns and 
bunions be unknown.] 
THE ARM. 
130. Clavicle.-The line of the clavicle and the projection of the joint at either 
end can always be felt, even in the fattest persons. Its direction is not perfectly hori- 
zontal, but slightly inclined downward when the arm hangs quietly by the side. When 
the body lies flat on the back, the shoulder not only falls Back, but rises a little, the 
weight of the limb being taken off. Hence the modern practice of treating fractures of 
the clavicle (in the early stage) by the supine position. 
On the front surface of the clavicle, not far from its acromial end, there is in many 
persons of mature age a spine-like projection of bone. So far as I know, it has not been 
described. A gentleman, himself a surgeon, showed me an instance in his own person. 
He suspected it was an exostosis. 
As a rule, the acromio-clavicular joint forms an even plane. But there is sometimes THE ARM. 
1057 
a knob of bone at the acromial end of the clavicle, or it may be only a thickening of 
the fibro-cartilage sometimes existing in the joint. In either case this relief might be 
mistaken for a dislocation or even for a fracture. A reference to the other shoulder 
might settle the question. 
[Being subcutaneous throughout, the clavicle can readily be seized and examined for 
fracture, syphilitic nodes, etc. If before a glass the arm be swung round, raised and 
lowered, the shoulder be shrugged, etc., we shall appreciate the fact that this is the only 
bony connection the arm has with the body, and to what a very large extent it is movable, 
the sterno-clavicular joint being the pivot, not only for motion of the clavicle, but of the 
entire arm.] 
131. Bony Points of the Shoulder.-We can distinctly feel the spine of the 
scapula and the acromion, more especially at the angle where they join behind the 
shoulder. This angle is the best place from which to measure in taking the comparative 
length of the arms. 
In some shoulders, though very rarely, there is an abnormal symphysis between the 
spine of the scapula and the acromion. There may indeed be two symphyses and two 
acromial bones, the acromion having two centres of ossification. These normal symphyses 
might be mistaken for fractures until we have examined the opposite shoulder, which is 
sure to present a similar conformation.1 [In dislocation of the shoulder the acromion 
process projects abnormally, with a hollow below it, due to absence of the head of the 
humerus from its proper place.] 
Tuberosities.-Projecting beyond the acromion (the arm hanging by the side) we 
can feel, through the fibres of the deltoid, the upper part of the humerus. It distinctly 
moves under the hand when the arm is rotated, it is not the head of the bone which is 
felt, but the tuberosities, the greater externally, the lesser in front. These tuberosities 
form the convexity of the shoulder. When the arm is raised this convexity disappears; 
there is a slight depression in its place. The head of the bone can be felt by pressing 
the fingers high up in the axilla. 
The absence of this prominence formed by the upper part of the humerus under the 
Deltoid, and the presence of a prominence low in the hollow of the axilla, or in front 
below the coracoid process, or behind on the back of the scapula, bespeak dislocation of 
the head of the bone. 
In examining obscure injuries about the shoulders it is worth remembering that in 
the normal relation of the bones and in every position the great tuberosity faces in the 
direction of the external condyle. The head of the bone faces very much in the direc- 
tion of the internal condyle. 
It is worth remembering, also, that the upper epiphysis of the humerus includes the 
tuberosities, and that it does not unite by bone to the shaft till about the twentieth 
year. 
By making deep pressure in front of the shoulder when the arm is pendent and 
supine, we can feel the bicipital groove [between the two tuberosities]. It looks directly 
forward, and runs in a line drawn vertically downward through the middle of the Biceps 
to its tendon at the elbow. We should be aware of this, lest it be mistaken for a 
fracture. 
132. Coraco-acromial Ligament.-Under the anterior fibres of the Deltoid we 
can distinctly feel the position and extent of the coraco-acromial ligament. A knife 
passed vertically through the middle of it goes at once into the shoulder-joint and strikes 
the bicipital groove with the tendon-a point to be remembered in excision. 
In persons of an athletic build the triangular form and beautiful structure of the 
Deltoid become conspicuous when the muscle is in action. The depression on the outer 
side of the arm, indicating its insertion, is the place selected for issues or setons. 
The arm being held up by an assistant, the anterior and posterior borders of the 
relaxed Deltoid admit of being raised, so that in amputation at the shoulder the knife can 
be introduced beneath the muscle to make the flap. 
133. Axilla.-[To show its borders best, let the model place his elbow on your 
shoulder and press down upon it, when the muscles will be brought into strong relief.] 
Th a anterior border of the axilla, formed by the Pectoralis major, follows the line of the 
fifth rib. In counting the ribs or in tapping the chest it is worth remembering that the 
highest visible digitation of the Serratus magnus is attached to the sixth rib. The angle 
of the digitation is directed forward, and corresponds to the upper edge of the rib. The 
second visible digitation corresponds to the seventh rib ; the interval between these digi- 
1 See Pruge on "Ossa Acromialia" (Zeitschriftfur rationelle Medizin), 3, Reihe, Bd. vii., 18-59. 
£• 7 1058 
LANDMARKS. 
tations, therefore, corresponds to the sixth intercostal space-a convenient place for tap- 
ping the chest (38). 
In the normal state no glands can be felt in the axilla. [But in feeling to see if they 
are enlarged, remember that they lie next the chest, at the inner, and not the outer, wall 
of the axilla-a position which facilitates also their removal.] 
134. Axillary Artery.-When the arm is raised to a right angle with the body, 
and the head of the humerus thereby depressed, the axillary artery is plainly felt beat- 
ing, and can be perfectly compressed on the inner side of the Coraco-brachialis. This 
muscle stands out in relief along the humeral side of the axilla, and is the best guide to 
the artery. A line drawn along its inner border-that is, down the middle [or rather at 
the junction of the middle and anterioi' thirds] of the axilla-corresponds with the 
course of the artery. 
The depth and form of the axilla alter in different positions of the arm. In the 
arm raised and abducted the axilla becomes nearly flat; hence this position is always 
adopted in operations. 
In opening abscesses in the axilla the incision should be made midway between the 
borders, and the point of the knife introduced from above downward. 
135. Brachial Artery.-When the arm is extended and supinated a line drawn 
from the deepest part of the middle of the axilla [or rather at the junction of the middle 
and anterior thirds] down the inner side of the Biceps to the middle of the bend of the 
elbow corresponds with the course of the brachial artery. The artery can be felt and 
compressed all the way down, but nowhere so effectually as midway, where it lies on the 
tendon of the Coraco-brachialis close to the inner side of the humerus. The only direc- 
tion to apply the pressure effectually is outward and a little backward, else the artery 
will slip off the bone. [A high bifurcation very often occurs, and will probably be per- 
ceptible on careful examination. 
The median nerve lies to the outside of the artery above, crosses it, usually in front 
at the middle, and lies to the inside below. It can usually be felt and very easily differ- 
entiated from the artery.] 
The musculo-spiral nerve and superior profunda artery wind round the back of the 
humerus about its middle, and come to the front of the external condyloid ridge [in the 
groove between the Supinator longus and the Brachialis anticus, where it is accessible to 
the battery and in operations]. Thus for full three inches above the condyles there 
is nothing to interfere with operations on the back of the bone, which is here broad 
and flat. 
136. Bend of Elbow.-At the bend of the elbow the tendon of the Biceps can be 
plainly felt, as well as the pulsation of the brachial artery close to its inner side, before 
dividing into the radial and ulnar. [If the arm be strongly fixed at a right angle-by 
attempting to lift a heavy table, for instance-the bicipital fascia can be outlined by the 
finger, and in many persons by the eye.] 
Cutaneous Veins.-The bend of the elbow in young children and in persons with 
fat and round arms presents a semicircular fold of which the curve embraces the lower 
part of the Biceps; but in muscular persons we see the distinct boundaries of the tri- 
angular space formed by the Pronator teres on the inner side and the Supinator longus 
on the outer. Here can be traced, standing out in strong relief under the thin white 
skin, the superficial veins, which, in days gone by, w7hen bloodletting was the fashion, 
were of such great importance. Their arrangement, although subject to variety, is very 
much like the branches of the letter M, the middle of the M being at the middle of the 
elbow. Of these branches, the median basilic, which runs over the tendon of the Biceps, 
is the largest and most conspicuous, and is generally selected for venesection ; it crosses 
the course of the brachial artery, nothing intervening but the semilunar aponeurosis from 
the tendon of the Biceps. 
137. Landmarks of Elbow.-It is of great importance to be familiar with the 
relative positions of the various bony prominences about the elbow. We can always feel 
the internal and external condyles. The internal is the more prominent of the two, and 
a trifle higher. 
Olecranon.-We can always feel the olecranon. This is somewhat nearer to the 
inner than to the outer condyle. [On strong flexion the groove in the humerus for the 
olecranon can be readily felt, and even seen.] Between the olecranon and the internal 
condyle is a deep depression in which lies the ulnar nerve (vulgarly called the " funny 
[or "crazy"] bone"). 
On the outer side of the olecranon, just below the external condyle, is a pit in the THE FOREARM AND WRIST. 
1059 
skin constant even in fat persons (when the elbow is extended). This pit is considered 
one of the beauties of the elbow in a graceful arm ; it is seen in a child as a pretty little 
dimple. [The dimple disappears on semiflexion.] To the surgeon it is most interesting, 
as in this valley behind the Supinator longus and the radial Extensors of the wrist he 
can distinctly feel the head of the radius rolling in pronation and supination of the 
forearm. It is therefore one of the most important landmarks of the elbow, since it 
enables us to say whether the head of the radius is in its right place, and whether it 
rotates with the shaft. 
Can the tubercle of the radius be felt? Yes. but only on the back of the forearm 
in extreme pronatidn. Its projection is then distinctly perceptible just below the head 
of the bone. 
Relations of the Olecranon and Condyles.-To examine the relative positions 
of the olecranon and condyles in the different motions of the elbow-joint, place the thumb 
on one condyle, the tip of the middle finger on the other, and the tip of the forefinger 
on the olecranon. In extension the highest point of the olecranon is never above the 
line of the condyles; indeed, it is just in this line. With the elbow at right angles the 
point of the olecranon is vertically below the line of the condyles. In extreme flexion 
the point of the olecranon lies in front of the line of the condyles. 
All these relative positions would be altered in the dislocation of the ulna, but not 
(necessarily) in a fracture of the lower end of the humerus. 
Sometimes, though rarely, we meet with a hook-like projection of bone above the 
internal condyle. It is called a " supracondyloid " process; it can be felt through the 
skin, with its concavity downward, and is a rudiment of the bony canal which in many 
Mammalia transmits the median nerve and ulnar artery. A third origin of the Pronator 
teres is always attached to it: this origin covers the brachial artery.1 
Bui'sse.-The subcutaneous bursa over the olecranon, if distended, would be as large 
as a walnut. A second bursa sometimes exists a little lower down upon the ulna. There 
is also a small subcutaneous bursa over each of the condyles. 
The vertical extent of the elbow-joint is limited above by a line drawn from one 
condyle to the other; below by a line corresponding to the lowest part of the head of 
the radius. 
138. Interosseous Arteries.-About one inch below the head of the radius the 
ulnar artery gives off- the common interosseous, and this divides about half an inch lower 
into the anterior and posterior interosseous. Thus, in amputating the forearm, say two 
inches below the head of the radius, four arteries at least would require ligature. 
By flexion of the elbow to the utmost the circulation through the brachial artery can 
be arrested, but the position is painful and can be tolerated only for a short time. 
Lymphatic Gland.--There is a small lymphatic gland just above the inner con- 
dyle in front of the intermuscular septum. It is the first to take alarm in poisoned 
wounds [chancres, etc.l of the hand. 
THE FOREARM AND WRIST. 
139. Ulna.-The edge of the ulna is subcutaneous, and can be felt from the olecra- 
non to the styloid process (in supination). Any irregularity could be easily detected. 
The styloid process of the ulna does not descend so low as the styloid process of the 
radius, or it would impede the free adduction of the hand. Its apex is on a level with 
the radio-carpal joint. The head of the ulna is plainly felt and seen projecting at the 
back of the wrist, especially in pronation of the forearm. It then lies between the 
tendons of the Extensor carpi ulnaris and Extensor minimi digiti. There is often a sub- 
cutaneous bursa over it. [In supination it is the styloid process, and not the head of the 
ulna, which is felt posteriorly.] 
140. Radius.-The upper half of the shaft of the radius [but not the head] is so 
covered by muscles that we cannot feel it; the lower half is more accessible to the touch, 
especially just above and just below the part where it is crossed by the Extensors of the 
thumb. Its styloid process is readily felt, and made all the more manifest by being 
covered by the first two Extensor tendons of the thumb. It descends lower and lies 
more to the front than the corresponding process of the ulna. The relative positions of 
1 See. on this subject a monograph, " Canalis Supracondyloideus Humeri," by W. Gruber, Peters- 
burg, 1856. 1060 
LANDMARKS. 
these styloid processes can be best examined by placing the thumb on one and the fore- 
finger on the other. 
Feel for the little bony pulley on the back of the radius near the wrist which keeps 
in place the third Extensor tendon of the thumb. This and the bone just above it is 
the place which we examine for a suspected fracture (termed Colles's) near the lower end 
of the radius. 
141. Carpus.-Below the styloid process of the radius, just on the inner side of 
the Extensors of the thumb, we feel the tubercle of the scaphoid bone. Between the 
styloid process and the tubercle is the level of the radio-carpal joint. A little lower we 
feel the trapezium. 
Just below the ulna on the palm of the hand we feel the pisiform bone, and on the 
inner side of this the cuneiform. 
There are several transverse furrows on the palmar aspect of the wrist. The lowest 
of these, which is slightly convex downward, corresponds with the upper edge of the 
anterior annular ligament and the intercarpal joint. The line of the radio-carpal joint, 
as already stated, is on a level with the apex of the styloid process of the ulna. 
In forcible [and resisted] flexion of the wrist the tendon of the Flexor carpi radialis 
and that of the Palmaris longus come up in relief. On the outer side of the first-named 
tendon we feel the pulse, the radial artery here lying close to the radius. 
The tendon of the Palmaris longus runs near the middle of the wrist, and close to its 
inner border runs the median nerve. In letting out deep-seated matter near the wrist 
the incision should be made close to and parallel with the inner edge of the radial 
Flexor tendon, so as to avoid injury to the median nerve. [The median nerve in the 
forearm lies under the Flexor sublimis digitorum, in a line drawn from the bend of the 
elbow just inside the artery to a point between the tendons of the Palmaris longus and 
the Flexor carpi radialis. It is here not only amenable to operations, but often is cut in 
accidents.] 
We can feel the tendon of the Flexor carpi ulnaris for some distance above the wrist. 
It overlies the ulnar artery and somewhat masks its pulsation. 
142. Pulse.-The " pulse at the wrist " is felt just outside the tendon of the 
Flexor carpi radialis. In feeling the pulse it should be remembered that in some 
cases the superficialis volse arises higher and is larger than usual. In such cases it 
runs by the side of the radial artery, and gives additional volume to the pulse. The 
old writers call it "pulsus duplex." When in doubt, therefore, it is well to feel the 
pulse in each wrist. 
143. Great Carpal Bursa.-The great synovial sheath under the annular ligament 
common to the Flexor tendons of the fingers and the long Flexor of the thumb extends 
upward about an inch and a half above the edge of the ligament, and downward as low 
as the middle of the palm. This general synovial sheath communicates with the special 
sheaths of the thumb and the little finger; not with that of the index, middle, and ring 
fingers. [Hence felons on the thumb and little finger are much more dangerous (and 
fortunately much more rare) than on the other fingers, since the pus may invade the 
main synovial sheath of the Flexors.] 
144. "Tabatiere anatomique."-On the outer side of the wrist we can distinctly 
see and feel, when in action, the three Extensor tendons of the thumb. Between the 
second and third there is deep depression at the root of the thumb which the French 
humorously call the " tabatiere anatomique." In this depression wre can make out-1, 
the relief of the superficial radial vein ; 2, the radial artery in its passage to the back 
of the hand; 3, the upper end of the metacarpal bone of the thumb. 
145. Tendons on the Back of the Wrist.-The relative positions of the several 
Extensor tendons of the wrist and fingers as they play in their grooves over the back of 
the radius and ulna can all be distinctly traced when the several muscles are put in 
action. The length of their synovial sheaths should be remembered. They vary from 
one inch and a half to two inches and a half. The longest of all are those of the 
Extensors of the thumb. When these sheaths are inflamed and swollen, the motion of 
the tendons becomes painful and gives rise to a feeling of crepitus, called " tenalgia 
crepitans " by some writers. It is said to be met with sometimes in pianists. [On the 
overstretching of these muscles, see §111.] 
146. Lines of Arteries.-The course of the radial artery corresponds with a line 
drawn from the outer border of the tendon of the Biceps at the bend of the elbow down 
the front of the forearm to the front of the styloid process of the radius. In the upper 
third of its course the artery is overlapped by the Supinator longus. To make allow- THE HAND. 
1061 
ance for this, the incision for the ligature of the artery in this situation should be made, 
not precisely in the line of its course, but rather nearer the middle of the forearm. 
The line of the ulnar artery runs from the middle of the bend of the elbow (slightly 
curving inward) to the outer side of the pisiform bone. The radial and ulnar arteries 
can, iu most cases, be effectually commanded by pressure well applied at the wrist in 
wounds of the palmar arch. 
Before we make incisions along the forearm it is always desirable to ascertain whether 
the ulnar artery, which usually runs under the superficial muscles, may not run abnor- 
mally over them; in which case its pulsations can be felt all down the forearm. 
THE HAND. 
147. It is beside the purpose here to examine the question whether the hand can tell 
more than the arm, the leg, or any other part of the body about the physical constitution 
of its owner, and to what use it has been put. Those who are interested in this subject 
should read a very elaborate treatise by Carus1 On the Reason and Meaning of the Differ- 
ent Forms of the Hand. Still less would I indulge curiosity by inquiring whether the 
professors of chiromancy, relying on the text " erit signum in manu tua et quasi monu- 
mentum ante oculos tuos," can advance any reasonable pretensions for their assertion 
that they can read in the furrows of the palm the future destiny of its master. 
148. Furrow in Palm.-The only furrow in the palm useful as a surgical land- 
mark is that which runs transversely across its lower third [from the ulnar border to the 
interspace between the fore and middle fingers], and is well seen when the fingers are 
slightly bent. This transverse furrow corresponds pretty nearly with the metacarpal 
joints of the [middle, ring, and little] fingers, with the upper limit of the synovial 
sheaths of the Flexor tendons of the four fingers (that of the little finger excepted (143)) ; 
also with the splitting of the palmar fascia into its four slips. The transverse metacarpal 
ligament lies in the same line with it. Again, a little below this furrow the digital arteries 
bifurcate to run along the opposite sides of the fingers. [The furrow which starts between 
the thumb and forefinger on the radial border of the hand, and runs toward the ulnar 
border, marks the level of the metacarpal joint of the forefinger. The third marked 
crease is caused by flexion of the thumb; the other two, by flexion of the fingers.] 
149. Interdigital Folds.-By pressure upon the interdigital folds of skin we can 1062 
LANDMARKS. 
knife introduced at the angle between the first and second metacarpal bones readily- finds 
the joint if the blade be directed outward. 
154. Sesamoid Bones.-The sesamoid bones of the thumb can be distinctly felt. 
Just above them-that is, nearer to the wrist-lies the joint between the metacarpal 
bone and the first phalanx. We should remember the position of these bones in ampu- 
tation at this joint. Mutatis mutandis, the same observations apply to the sesamoid 
bones of the great toe. 
The Extensor tendon of the last joint of the thumb crosses the apex of the first 
interosseous space. Under the tendon and in the angle between the bones we feel the 
radial artery just before it sinks into the palm. 
155. Subcutaneous Veins.-The veins on the back of the hand, and their arrange- 
ment in the form of arches which receive the digital veins, are sufficiently obvious. The 
number and arrangement of the arches may vary, but in all hands it is interesting to 
notice that the veins from the fingers run up between the knuckles and out of harm's 
way. 
156. Interosseous Arteries.-Since the dorsal interosseous arteries, like the palm- 
ar, run along the interosseous spaces, incisions to let out pus should always be made 
along the lines of the metacarpal bones. 
157. Digital Bursse.-Small subcutaneous bursae are sometimes developed over the 
knuckles and the backs of the joints of the fingers. They often become enlarged and 
unseemly in persons of a rheumatic or gouty tendency. 
158. Knuckles and Digital Joints.-The three rows of projections called "the 
knuckles" are formed by the proximal bones of the several joints: thus the first row is 
formed by the ends of the metacarpals; the second, by the ends of the first phalanges, 
and so forth. In amputations of the fingers it is well to remember that in all cases the 
line of the joints is a little in advance of the knuckles; that is, nearer the end of the 
fingers. 
Long and graceful fingers, coupled with thickness and breadth of the sentient pulp at 
their ends and too great arching of the nails, have been regarded, ever since the days of 
Hippocrates, as not unlikely indications of a tendency to pulmonary disease. 
[Staining the nails (e. g. by nitric acid) affords a means of determining the fact and 
the rate of their growth, and therefore of the nutritive processes in the corresponding 
arm or leg.] p. 1063-1064 missing INDEX. 
A. 
Abdomen, 858 
apertures found in, 859 
boundaries of, 858 
landmarks of, 1041 
lymphatics of, 646 
muscles of, 411 
regions of, 859 
viscera of, 860, 1044 
Abdominal aorta, 571 
branches of, 574 
surgical anatomy of, 573 
lines, 1041 
muscles, 411 
ring, external, 413 
internal, 996 
viscera, position of, 860 
Abducens nerve, 731 
Abductor indicis muscle, 456 
minimi digiti muscle, hand, 
455 
foot, 490 
pollicis muscle, hand, 452 
foot, 489 
Aberrant duct of testis, 971 
Absorbent glands, 638 
Absorbents, 638 
Accelerator urinse muscle, 1014 
Accessorii orbicularis oris, 377 
Accessorius ad sacro-lumbalem 
muscle, 406 
pedis, 491 
Accessory obturator nerve, 773 
palatine canals, 193 
pudic artery, 588 
Acervulus cerebri, 702 
Acetabulum, 265 
Acromial end of clavicle, frac- 
ture of, 458 
nerves, 751 
region, muscles of, 432 
thoracic artery, 556 
Acromio-clavicular joint, 324 
Acromion process, 235 
fracture of, 458 
Actions of muscles. See each 
group of muscles. 
Adductor brevis muscle, 471 
longus muscle, 470 
magnus muscle, 471 
pollicis muscle, hand, 454 
foot, 492 
Adenoid connective tissue, 48 
Adipose tissue, 49 
Afferent vessels of kidney, 947 
Air-cells, 938 
Air-sacs of lung, 938 
Alae of vomer, 197 
Alar ligaments, 310 
of knee, 351 
thoracic artery, 556 
Alimentary canal, 839 
development of, 130 
subdivisions of, 839 
Allantois, 111, 955 
Alveolar artery, 524 
process, 189, 199 
Alveoli of lower jaw, 199 
of upper jaw, 189 
formation of, 849 
of stomach, 872 
Amnion, 109 
Amniotic cavity, 110 
Amphiarthrosis, 298 
Ampullae of semicircular canals, 
833 
of tubuli lactiferi, 909 
Amygdalae, 851 
of cerebellum, 710 
Anal fascia, 1022 
Anastomosis of arteries, 501 
Anastomotica magna of brachial, 
561 
of femoral, 599 
Anatomical neck of humerus, 
238 
fracture of, 458 
[position of hand, 250] 
Anconeus muscle, 447 
Andersch, ganglion of, 737 
[Aneurismal thrill, how to pro- 
duce, 596] 
Aneurisms of abdominal aorta, 
573 
of arch of aorta, 506 
of thoracic aorta, 570 
[Angle at knee and elbow, 242] 
of jaw, 201 
of pubes, 265 
of rib, 225 
sacro-vertebral, 153 
Angular artery, 518 
convolution, 676 
movement, 300 
process, external, 168 
internal, 168 
vein, 614 
Animal constituent of bone, 58 
Ankle-joint, 354 
relations of tendons and ves- 
sels to, 356 
Annular ligament of radius and 
ulna, 333 
of wrist, anterior, 449 
posterior, 450 
of ankle, anterior, 487 
external, 488 
internal, 488 
of stapes, 830 
Annulus ovalis, 909 
Anterior annular ligament, wrist, 
449 
ankle, 487 
Anterior chamber of eye, 816 
crural nerve, 773 
dental canal, 187 
ethmoidal cells, 182 
fontanelle, 184 
fossa of skull, 206 
nasal spine, 190 
palatine canal, 189, 208 
fossa, 189, 208 
radicular zone, 658 
region of skull, 213 
triangle of neck, 525 
Antihelix, 823 
fossa of, 823 
Antitragicus muscle, 824 
Antitragus, 823 
Antrum of Highmore, 187 
[percussion of, 188, 189] 
landmarks of, 1031 
Anus, 1010 
development of, 132 
landmarks of, 1047 
muscles of, 1011 
Aorta, 502 
abdominal, 571 
branches of, 574 
development of, 127 
division of, 1042 
landmarks of, 1042 
surgical anatomy of, 506 
arch of, 503 
ascending part of, 504 
branches of, 507 
descending part of, 505 
peculiarities of, 506 
of branches of, 507 
sinuses of, 504 
surgical anatomy of, 506 
transverse portion of, 504 
descending, 569 
thoracic, 569 
branches of, 570 
surgical anatomy of, 570 
Aortic opening of diaphragm, 
424 
of heart, 912 
plexus, 796 
semilunar valves, 912 
sinuses, 913 
Apertura scalse vestibuli cochleae, 
832 _ 
Aponeurosis, 364 
of deltoid, 432 
of external oblique in inguinal 
region, 992 
infraspinous, 434 
of occipito-frontalis, 367 
subscapular, 433 
suprahyoid, 388 
of soft palate, 851 
supraspinous, 433 
Apophysis, 142 
1065 1066 
INDEX. 
Apparatus ligamentosus colli, 309 
Appendages of eye, 819 
of skin, 92 
of uterus, 984 
Appendices epiploicae, 869 
Appendix of right auricle, 907 
of left auricle, 911 
vermiformis, 882 
[surgical anatomy of, 882] 
Aqua labyrinthi, 837 
Aquaeductus cochleae, 174, 834 
vestibuli, 174, 832 
Fallopii, 174, 827 
Sylvii, 701 
Aqueous humor, 816 
Arachnoid of brain, 663 
of cord, 653 
Arantii corpora, 911, 912 
Arantius, ventricle of, 667 
Arbor vitae uterina, 981 
of cerebellum, 711 
Arch of aorta, 503 
peculiarities of, 506 
branches of, 507 
surgical anatomy, 506 
of pubes, 269 
of a vertebra, 143 
supraorbital, 167 
crural or femoral, 1004 
palmar superficial, 566 
deep, 563 
plantar, 610 
zygomatic, 212 
Arches, pharyngeal, 117 
aortic, foetal, 127 
Arciform fibres of medulla ob- 
longata, 668 
Arcuate fibres of cerebrum, 707 
of cerebellum, 711 
Area, germinal, 102 
Areola of breast, 988 
Areolar tissue, 46 
Arm, back of, muscles of, 438 
front of, muscles of, 435 
arteries of, 541 
bones of, 237 
fascia of, 435 
landmarks of, 1054 
lymphatic glands of, 643 
lymphatics of, 643 
superficial fascia of, 431 
nerves of, 755 
veins of, 623 
Arnold's nerve, 739 
canal for, 174 
ganglion, 729 
Arteria centralis retinae, 532 
Arteriae propriae renales, 949 
receptaculi, 530 
Arteries, development of, 126 
Arteries, general anatomy of, 78 
anastomoses of, 501 
capillary, 81 
distribution of, 501 
mode of division, 501 
mode of origin of branches, 
501 
nerves of, 81 
sheath of, 80 
structure of, 78 
subdivision of, 501 
systemic, 501 
vessels of, 80 
Arteries or artery, accessory pu- 
dic, 588 
Arteries or artery- 
acromial thoracic, 556 
alar thoracic, 556 
alveolar, 524 
anastomotica magna of bra- 
chial, 561 
of femoral, 599 
angular, 518 
[anterior and internal frontal, 
537] 
cerebral, 533 
[cerebral, 534, 537] 
choroid, 534 
ciliary, 532 
communicating, 534 
intercostal, 552 
spinal, 549 
aorta, 502 
abdominal, 571 
arch of, 503 
ascending part, 504 
descending part, 505 
transverse portion, 504 
thoracic, 569 
articular, knee, 602 
ascending cervical, 550 
pharyngeal, 520 
auditory, 549, 838 
auricular anterior, 521 
posterior, 520 
axillary, 554 
landmarks of, 1055 
azygos of knee, 602 
basilar, 549 
brachial, 558 
bronchial, 570, 939 
buccal, 524 
of bulb, 589 
calcanean, internal, 609 
carotid, common, 509 
external, 512 
internal, 528 
carpal ulnar, 569 
of cavernous body, 589 
radial, 564 
centralis retinae, 532 
cerebellar, 549 
cerebral, 534, 549 
ascending cervical, 550 
superficial, 551 
princeps, 519 
profunda, 553 
choroid anterior, 534 
posterior, 549 
ciliary, 532 
circle of Willis, 550 
[circular, of uterus, 982] 
circumflex, of arm, 557 
of thigh, 598 
iliac, 593 
superficial, 597 
cochlear, 838 
coccygeal, 590 
colica dextra, 579 
media, 579 
sinistra, 579 
coeliac axis, 574 
comes nervi ischiadici, 590 
phrenici, 552 
common carotid, 509 
[femoral, 594] 
iliac, 582 
communicating, anterior cere- 
bri, 534 
posterior cerebri, 534 
Arteries or artery- 
communicating branch of ul- 
nar, 569 
coronary of heart, 507 
of lip, 518 
[cortical, 539] 
[system of, in brain, 534,537] 
cremasteric, 593 
crico-thyroid, 515 
cystic, 576 
deep branch of ulnar, 569 
cervical, 552 
[femoral, 594] 
palmar arch, 562 
temporal, 524 
deferent, 586 
dental inferior, 523 
superior, 524 
descending aorta, 569 
palatine, 524 
digital plantar, 610 
of ulnar, 569 
dorsal, of penis, 589 
of scapula, 557 
dorsalis hallucis, 606 
indicis, 564 
linguae, 515 
pedis, 605 
pollicis, 564 
epigastric, 593 
landmarks of, 1054 
superior, 552 
superficial, 597 
ethmoidal, 532 
external carotid, 512 
plantar, 610 
iliac, 591 
facial, 516 
landmarks of, 1058 
femoral, 594 
compression of, 1048 
landmarks of, 1049 
deep, 598 
frontal, 532 
landmarks of, 1058 
[ganglionic system of, in brain, 
536] 
gastric, 574, 577 
gastro-duodenalis, 575 
gastro-epiploica dextra, 576 
sinistra, 577 
gluteal, 591 
inferior, 590 
landmarks of, 1051 
helicine, 965 
hemorrhoidal inferior, 589 
middle, 586 
superior, 579 
hepatic, 574 
hyoid branch of lingual, 515 
of superior thyroid, 514 
hypogastric in foetus, 584, 916 
ileo-colic, 579 
iliac, common, 582 
external, 591 
internal, 584 
ilio-lumbar, 591 
inferior cerebellar, 549 
dental, 523 
labial, 518 
laryngeal, 550 
mesenteric, 579 
profunda, 561 
pyloric, 575 
thyroid, 550 INDEX. 
1067 
Arteries or artery- 
infraorbital, 524 
innominate, 508 
intercostal, 571 
anterior, 552 
superior, 552 
internal auditory, 838 
carotid, 528 
iliac, 584 
mammary, 551 
maxillary, 522 
plantar, 610 
interosseous ulnar, 568 
landmarks of, 1059 
of foot, 607 
landmarks of, 1059 
of hand, 565, 568 
intestini tenuis, 577 
labial inferior, 518 
lachrymal, 531 
laryngeal superior, 515 
inferior, 550 
lateral sacral, 591 
spinal, 547 
lateralis nasi, 518 
[lenticulo-striate, 536] 
lingual, 515 
long ciliary, 532 
thoracic, 556 
lumbar, 581 
malleolar, 605 
mammary internal, 551 
landmarks of, 1035 
masseteric, 524 
maxillary internal, 521 
median, of forearm, 568 
of spinal cord, 549 
mediastinal, 552 
posterior, 571 
[medullary, 539] 
meningeal anterior, 530 
middle, 523 
landmarks of, 1027 
small, 523 
from occipital, 519 
from pharyngeal, 520 
from vertebral, 548 
mesenteric inferior, 579 
superior, 577 
metacarpal, 564 
metatarsal, 606 
[middle and internal frontal, 
537] 
[cerebral, 534, 537] 
sacral, 582 
musculo phrenic, 552 
mylo-hyoid, 523 
nasal, 525 
of ophthalmic, 532 
of septum, 518 
nutrient of humerus, 561 
femur, 599 
fibula, 609 
radius, 568 
tibia, 609 
ulna, 567 
obturator, 587 
occipital, 519 
oesophageal, 571 
[of brain, 534] 
[of Broca's convolution, 538, 
540] 
[of cerebral hemorrhage, 536] 
[of the ascending frontal con- 
volution, 538] 
Arteries or artery - 
[of the ascending parietal con- 
volution, 538 | 
[of the medulla oblongata, 548] 
[of the spinal cord, 547] 
of the vas deferens, 586, 968 
ophthalmic, 530 
orbital, 524 
ovarian, 581 
palatine, ascending, 517 
descending, 524 
posterior, 524 
of pharyngeal, 520 
palmar arch, superficial, 566 
deep, 563 
palmar interossei, 565 
palpebral, 532 
pancreatic, 577 
pancreatico-duodenalis, 576 
inferior, 577 
perforating, of hand, 565 
of thigh, 599 
of foot, 610 
of intercostal, 552 
plantar, 609 
pericardiac, 552, 570 
perineal, superficial, 589 
transverse, 589 
peroneal, 608 
anterior, 609 
pharyngea ascendens, 520 
phrenic, 581 
pollicis, 564 
popliteal, 599 
landmarks of, 1053 
posterior auricular, 520 
[cerebral, 538, 549] 
communicating, 534 
meningeal, from vertebral, 
548 
palatine, 524 
princeps cervicis, 519 
profunda of arm, inferior, 561 
superior, 561 
cervicis, 552 
femoris, 598 
pterygoid, 524 
pterygo-palatine, 524 
pudic, deep external, 598 
landmarks of, 1051 
superficial external, 598 
internal, 588 
pulmonary, 502, 938 
pyloric inferior, 575 
of hepatic, 575 
radial, 562 
landmarks of, 1060 
radialis indicis, 564 
ranine, 516 
recurrent interosseous, 568 
radial, 564 
ulnar, anterior, 567 
posterior, 567 
tibial, 605 
renal, 580 
sacral lateral, 591 
middle, 582 
scapular, posterior, 551 
sciatic, 590 
short ciliary, 532 
sigmoid, 579 
spermatic, 581, 968 
spheno-palatine. 525 
spinal, anterior, 549 
lateral, 549 
posterior, 549 
Arteries or artery- 
spinal, median, 549 
splenic, 576 
sterno-mastoid, 519 
stylo-mastoid, 520 
subclavian, 542 
landmarks of, 1033 
sublingual, 515 
submaxillary, 518 
submental, 518 
subscapular, 556 
superficial cervical, 551 
circumflex iliac, 593 
[femoral, 594] 
perineal, 589 
palmar arch, 566 
superficialis volse, 564 
superior cerebellar, 549 
epigastric, 552 
hemorrhoidal, 580 
intercostal, 552 
laryngeal, 515 
mesenteric, 577 
profunda, 561 
thoracic, 556 
thyroid, 514 
supraorbital, 531 
suprarenal, 580 
suprascapular, 550 
sural, 602 
[Sylvian, 534, 537] 
tarsal, 606 
temporal, 521 
anterior, 521 
deep, 524 
middle, 521 
posterior, 521 
[terminal, 535, 539] 
thoracic, acromial, 556 
alar, 556 
aorta, 569 
long, 556 
superior, 556 
[thymic, 942] 
thyroid axis, 550 
thyroid inferior, 550 
superior, 514 
thyroidea ima, 508, 941 
tibial anterior, 603 
landmarks of, 1054 
posterior, 607 
landmarks of, 1055 
recurrent, 605 
tonsillar, 518 
transverse facial, 521 
transversalis colli, 551 
tympanic, from internal caro- 
tid, 530 
from internal maxillary, 523 
ulnar, 566 
landmarks of, 1061 
recurrent anterior, 567 
posterior, 567 
umbilical in foetus, 586, 916 
uterine, 586 
[uncinate, 539] 
vaginal, 586 
vasa aberrantia of arm, 560 
brevia, 577 
intestini tenuis, 577 
vertebral, 546 
vesical inferior, 586 
middle, 586 
superior, 586 
vestibular, 838 
Vidian, 524 1068 
INDEX. 
Arteriolae rectse, 950 
Arthrodia, 298 
Articular arteries (knee), from 
popliteal, 603 
cartilage, 141 
lamella of bone, 296 
processes of vertebrae, 143 
Articulations in general, 296 
different kinds of, 297 
acromio-clavicular, 324 
ankle, 354 
astragalo-calcanean, 358 
astragalo-scaphoid, 360 
atlo-axoid, 306 
calcaneo-astragaloid, 358 
calcaneo-cuboid, 359 
calcaneo-scaphoid, 359 
carpo-metacarpal, 338 
carpal, 336 
classification of, 297 
coccygeal, 321 
chondro-sternal, 315 
costo-transverse, 315 
costo-vertebral, 313 
elbow, 329 
femoro tibial, 347 
hip, 342 
immovable, 297 
knee, 346 
metacarpal, 340 
metacarpo-phalangeal, 340 
metatarso-phalangeal, 361 
metatarsal, 361 
mixed, 298 
movable, 298 
movements of, 300 
occipito-atloid, 309 
occipito-axoid, 309 
pelvis, 320 
pelvis with spine, 318 
phalanges, 341 
pubic, 321 
radio-carpal, 335 
radio-ulnar, inferior, 333 
middle, 333 
superior, 333 
sacro-coccygeal, 320 
sacro-iliac, 319 
sacro-sciatic, 320 
sacro-vertebral, 318 
scapulo-clavicular, 324 
scapulo-humeral, 326 
shoulder, 326 
sterno-clavicular, 322 
landmarks of, 1034 
of sternum, 317 
tarso-metatarsal, 360 
tarsal, 357 
temporo-maxillary, 310 
tibio-fibular, inferior, 354 
middle, 353 
superior, 353 
of tympanic bones, 829 
vertebral column, 301 
wrist, 335 
Arytseno-epiglottideus, superior, 
926 
inferior, 926 
Arytreno-epiglottidean folds, 923 
Arytenoid cartilages, 920 
glands, 927 
muscle, 925 
Ascending colon, 883 
palatine artery, 517 
pharyngeal artery, 520 
[Asterion, 685] 
Astragalus, 288 
development of, 293 
Atlas, 144 
development of, 151 
Atlo-axoid articulation, 306 
Atrabiliary capsules, 952 
Attollens aurem muscle, 369 
Attrahens aurem muscle, 369 
Auditory artery, 838 
veins, 838 
canal, 825 
meatus, external, 173 
internal, 174 
nerve, 736, 838 
process, 173 
vesicle, 122 
Auricle of ear, 823 
cartilage of, 823 
ligaments of, 823 
of heart, left, 911 
appendix of, 907, 911 
sinus of, 911 
right, 907 
openings in, 908 
valves in, 908 
sinus of, 907 
septum of, 906, 912 
Auricular artery, posterior, 520 
anterior, 521 
fissure, 174, 210 
lymphatic glands, 640 
nerve of vagus, 740 
posterior from facial, 735 
surface of sacrum, 154 
veins, anterior, 612 
posterior, 613 
Auricularis anterior muscle, 369 
posterior, 369 
superior, 369 
magnus nerve, 750 
Auriculo-temporal nerve, 728 
Auriculo-ventricular groove of 
heart, 907 
opening, left, 912 
right, 909 
Axes of the pelvis, 270 
Axilla, 553 
dissection of, 426 
landmarks of, 1057 
Axillary artery, 554 
landmarks of, 1058 
peculiarities, 555 
surgical anatomy of, 555 
branches of, 556 
lymphatic glands, 643 
space, 553 
vein, 625 
Axis, or second vertebra, 145 
development of, 152 
cerebro-spinal, 652 
coeliac, 574 
thyroid, 550 
Axis-cylinder of nerve-tubes, 70 
Azygos artery, articular, 602 
veins, 627 
uvulae muscle, 395 
B. 
Bacillary layer of retina, 815 
Back, furrows of, 1037 
muscles of, first layer, 399 
second layer, 403 
third layer, 404 
Back- 
muscles of fourth layer, 405 
fifth layer, 409 
Ball-and-socket joint. See Enar- 
throdia. 
Bartholine, duct of, 854 
glands of, 978 
Base of brain, 687 
of skull, 205 
external surface, 208 
internal surface, 205 
Basement membranes, 49 
Basilar artery, 547 
membrane of cochlea, 835 
process, 162 
suture, 203 
Basilic vein, 624 
median, 624 
Basio-glossus muscle, 390, 391 
[Basion, 685] 
Basis vertebrarum venae, 629 
Bauhin, valve of, 882 
Beak of corpus callosum, 692 
Beaunis et Bouchard, Table of 
Development of Foetus 
from, 139 
[Bed-sores and sacral canal, 154] 
Bend of elbow, 559 
Biceps muscle of arm, 436 
of thigh, 477 
[Bichat, fissure of, 675, 697] 
Bicipital groove, 238 
tuberosity, 248 
Bicuspid teeth, 841 
Biliary ducts, 895, 896 
structure of, 897 
Biventer cervicis muscle, 408 
Bladder, 955 
ligaments of, 957 
trigone of, 958 
vessels and nerves of, 959 
female, 978 
Blastodermic membrane, 102 
Blood, general anatomy of: 
circulation of, in adult, 907 
in foetus, 915 
crystals, 39 
gases of, 39 
globules, 36 
[third corpuscle of, 38] 
[Blood-plaques, 38] 
[Blood-vessels of the medulla 
oblongata, 548] 
[of the spinal cord, 547] 
Bochdalek, ganglion of, 725 
on musculus triticeo-glossus, 
926, note 
Body of a tooth, 841 
of a vertebra, 143 
Bone, general anatomy of, 54 
animal constituent of, 58 
apophysis of, 142 
articular lamella of, 296 
canal iculi of, 56 
cancellous tissue of, 54 
cells, 58 
chemical analysis of, 58 
compact tissue of, 54 
diploe of, 141 
development of, 59 
earthy constituent of, 58 
eminences and depressions of, 
142 
epiphysis of, 142 
growth of, 62 INDEX. 
1069 
Bone- 
Haversian canals of, 56 
systems of, 56 
inorganic constituent of, 59 
lacunte of, 57 
lamellae of, 57 
lymphatics of, 55 
marrow of, 54 
medullary canal of, 54, 141 
membrane of, 54 
microscopic appearances, 55 
nerves of, 55 
organic constituent of, 58 
ossification of, 59 
ossific centres, number of, 63 
periosteum of, 54 
spongy tissue of, 141 
vessels of, 55 
Bones, forms of-viz. long, short, 
flat, mixed, irregular, 141 
number of, in the body, 141 
Bones or bone, descriptive anat- 
omy of, 141 
astragalus, 288 
atlas, 144 
axis, 145 
calcaneum, 284 
carpal, 250 
clavicle, 229 
coccyx, 157 
cranial, 160 
cuboid, 287 
cuneiform of carpus, 252 
of tarsus, 289, 290 
ear, 828 
ethmoid, 181 
facial, 185 
femur, 270 
fibula, 281 
frontal, 166 
hand, 250 
humerus, 237 
hyoid, 219 
ilium, 261 
incus, 829 
inferior maxillary, 137 
turbinated, 196 
innominate, 260 
ischium, 263 
lachrymal, 191 
lesser lachrymal, 191 
lingual, 219 
magnum, 254 
malar, 192 
malleus, 829 
maxillary, inferior, 197 
superior, 186 
metacarpal, 255 
metatarsal, 291 
nasal, 185 
occipital, 160 
orbicular, 830 
palate, 193 
parietal, 164 
patella, 277 
pelvic, 267 
phalanges of foot, 292 
of hand, 257 
pisiform, 252 
pubic, 264 
radius, 248 
ribs, 224 
sacrum, 152 
scaphoid of carpus, 250 
of tarsus, 289 
Bones or bone- 
scapula, 233 
semilunar, 252 
sesamoid, 294 
sphenoid. 176 
sphenoidal, spongy, 180 
stapes, 830 
sternum, 222 
superior maxillary, 186 
tarsal, 284 
temporal, 170 
tibia, 278 
trapezium, 252 
trapezoid, 254 
triquetral, 184 
turbinate, inferior, 196 
middle, 182 
superior, 183 
tympanic, 175 
ulna, 243 
unciform, 255 
vertebra prominens, 147 
vertebrae, cervical, 143 
dorsal, 147 
lumbar, 149 
vomer, 197 
Wormian, 184 
Bone, articular lamella of, 296 
Bowman's capsule, 946 
Brachia of optic lobes, 702 
Brachial artery, 558 
branches of, 561 
peculiarities of, 559 
surgical anatomy of, 560 
lymphatic glands, 643 
plexus, 752 
region, posterior, muscles of, 
446, 447 
anterior, 440, 443 
veins, 625 
Brachialis anticus muscle, 437 
Brain, base of, 687 
[blood-vessels of, 534] 
convolutions of, 672 
development of, 118 
dura mater of, 661 
general anatomy of, 72 
interior of, 690 
landmarks of, 1037 
lobes of, 687 
membranes and dissection, 661 
subdivision into parts, 664 
[topography of, 681] 
upper surface of, 672 
weight of, 665 
[Brain-centres for motion, 681] 
Breasts, 988 
[Bregma, 685] 
Brim of pelvis, 268 
Broad ligaments of uterus, 981 
formation of, 864 
[Broca's convolution, 676] 
Bronchi, right and left, 927 
septum of, 928 
in lung, 936 
Bronchial arteries, 571, 939 
lymphatic glands, 650 
septum, 928 
tubes. See Bronchi. 
veins, 628, 939 
Brunner's glands, 879 
Bubonocele, 998 
Buccal arteries, 524 
cavity, development of, 131 
glands, 840 
Buccal lymphatic glands, 640 
nerve of facial, 736 
of inferior maxillary, 728 
veins, 614 
Buccinator muscle, 377 
Bulb, artery of, 589 
of corpus cavernosum, 965 
of corpus spongiosum, 966 
olfactory, 688,716 
Bulbi vestibuli, 978 
Bulbous portion of the urethra, 
960 
Bulbs of the fornix, 689 
Burdach's column, 658 
Burns, ligament of, 1003, note 
[Bursa of heel, 357] 
[prepatellar, 350] 
[subpatellar, 350] 
Bursae mucosae, 297 
Bursae of shoulder, 327, 328 
carpal, 1060 
digital, 1062 
of ham, 601 
of olecranon, 1058 
of wrist, 1060 
plantar, 1056 
popliteal, 1052 
prepatellar, 1052 
Bursal synovial membranes, 297 
Buttocks, folds of, 1050 
landmarks of, 1051 
c. 
Caecum, 882 
[surgical anatomy of, 882] 
Calamus scriptorius, 713 
Calcanean arteries, internal, 609 
Calcaneo-astragaloid ligaments, 
358 
Calcaneo-cuboid ligaments, 359 
Calcaneo-scaphoid ligaments, 
359 
Calcaneum, 284 
Calcarine fissure, 678 
Calices of kidney, 945 
Callender, Mr., researches on 
femoral hernia, 1003 
Calloso-marginal fissure, 678 
[Calvarium, 662] 
Camper's ligament. See Triang- 
ular Ligament of Urethra. 
Canals or canal, accessory pala- 
tine, 193 
alimentary, 839 
anterior dental, 187 
palatine, 189 
for Arnold's nerve, 174 
auditory, 825 
carotid, 173, 174 
central, of modiolus, 833 
for chorda tympani, 171, 826 
of cochlea, 833 
crural, 1006 
dental posterior, 187 
ethmoidal, 169 
femoral, 1006 
Haversian, of bone, 56 
of Huguier, 171 
incisive, 208 
inferior dental, 199 
infraorbital, 186 
inguinal, 996 
landmarks of, 1044 
for Jacobson's (tympanic) 
nerve, 174 1070 
INDEX. 
Canals or canal-- 
lachrymal, 822 
naso-palatine, 189 
of Nuck, 975, 988 
of Petit, 818 
palatine, anterior, 189 
posterior, 187 
pterygo-palatine, 17 8 
sacral, 155 
of Schlemm, 811 
spermatic, 996 
of spinal cord, 120 
spiral, of cochlea, 833 
of Stilling, 817 
of modiolus, 833 
semicircular, 832 
for tensor tympani, 175, 809 
temporo-malar, 193 
vertebral, 160 
Vidian, 180 
of Wirsung, 898 
Canal iculi of bone, 58 
of eyelids, 822 
Canalis centralis modioli, 833 
reuniens, 837 
spiralis modioli, 834 
Cancellous tissue of bone, 54, 
141 
Canine eminence, 186 
fossa, 186 
teeth, 841 
Canthi of eyelids, 814 
Capillaries, 81 
Capitellum of humerus, 241 
Capsular ligament of hip, 342 
of knee, 348 
of shoulder, 326 
of thumb, 338 
of vertebras, 304 
Capsule, external, of brain, 694 
internal, of brain, 693 
in foetus, 122 
of Glisson, 892 
of kidney, 945 
of lens, 817 
of Tenon, 805 
Capsules, suprarenal, 953 
Caput cornu posterioris, 658 
gallinaginis, 959 
Cardiac lymphatics, 650 
nerves, 789, 790 
from pneumogastric, 741 
plexus of nerves, deep, 792 
superficial, 793 
veins, 636 
Cardinal veins, foetal, 128 
Carotid artery, common, 509 
branches of (occasional), 
511 
peculiarities of, 511 
surgical anatomy of, 511 
external, 512 
branches of, 514 
surgical anatomy of, 515 
internal, 528 
branches of, 530 
peculiarities of, 530 
surgical anatomy, 530 
branch of Vidian, 727 
canal,.174 
ganglion, 789 
groove, 177 
plexus, 789 
triangle, inferior, 526 
superior, 526 
Carpal arteries, from radial, 564 
from ulnar, 569 
ligaments, 336 
Carpo-metacarpal articulations, 
338 
Carpus, 250 
development of, 259 
articulations of, 336 
Cartilage, general anatomy of, 
50 
articular, 51 
cellular, 50 
fibrous, 53 
hyaline, 51 
intercellular substance of, 51 
reticular, 53 
temporary, 52 
descriptive anatomy of: 
arytenoid, 920 
of auricle, 823 
of bronchi, 937 
costal, 52, 228 
cricoid, 920 
cuneiform, 921 
of ear, 823, 825, 829 
ensiform, 222 
of epiglottis, 921 
of larynx, 919 
of the nose, 802 
of the pinna, 823 
of Santorini, 921 
semilunar of knee, 349 
of septum of nose, 803 
tarsal, 820 
thyroid, 919 
of trachea, 929 
of Wrisberg, 921 
xiphoid, 222 
Cartilago triticea, 922 
Caruncula lachrymalis, 821 
mammillaris, 716 
Carunculae myrtiformes, 978 
Cauda equina, 775 
Cava, inferior, 633 
peculiarities, 633 
superior, 627 
Cavernous body, artery of, 589 
groove, 177 
nerves of penis, 797 
plexus, 789 
sinus, 621 
nerves in, 732 
Cavity, cotyloid, 265 
glenoid, 236 
of pelvis, 268 
sigmoid, 245 
Cells, 40 
of bone, 58 
ethmoidal, 182 
mastoid, 172 
Cellular tissue, lymphoid, 48 
mucoid, 48 
retiform, 48 
Cement of teeth, 845 
formation of] 848 
Central canal of cord, 656 
gray nucleus, 659 
lobe of cerebrum, 677 
Centres of ossification, 63 
Centrum ovale, majus, 691 
minus, 690 
Cephalic vein, 624 
median, 624 
Cerebellar arteries, anterior, 549 
superior, 549 
Cerebellar arteries- 
inferior, 549 
column, 658 
veins, 619 
Cerebelli incisura, anterior, 709 
posterior, 709 
Cerebellum, 708 
corpus dentatum of, 710 
hemispheres of, 709 
lam i use of, 711 
lobes of, 710 
lobulus centralis of, 709 
median lobe of, 709 
peduncles of, 711 
structure of, 710 
under surface of, 709 
upper surface of, 708 
the valley of, 709 
ventricle of, 712 
weight of, 708 
Cerebral arteries, 534 
anterior, 534 
middle, 534 
posterior, 549 
convolutions, 672 
[localization and topography, 
681] 
lymphatics, 641 
veins, 618 
ventricles, 690 
Cerebro-spinal axis, 653 
fluid, 664 
nerves, 69 
Cerebrum, 664, 672 
base of, 687 
commissures of, 707 
convolutions of, 672 
crura of, 690 
fibres of, 706 
fissures of, 675 
general arrangement of its 
parts, 690 
gray matter of, 72, 703 
hemispheres of, 672 
interior of, 690 
labia of, 691 
lobes of, 687 
peduncles of, 689 
structure of, 703 
sulci, 673 
under surface, 687 
upper surface, 672 
ventricles of, 692, 700 
Ceruminous glands, 826 
Cervical artery, ascending, 550 
superficial, 551 
princeps, 519 
profunda, 552 
Cervical fascia, 382, 383 
ganglion, inferior, 791 
middle, 790 
superior, 786 
lymphatic glands, deep, 642 
superficial, 642 
nerves, 746 
anterior divisions of, 749 
posterior divisions of 747 
roots of, 642 
plexus, 749 
deep branches of, 751 
posterior, 747 
superficial branches of, 750 
veins, ascending, 617 
deep, 617 
vertebrae, 143 INDEX. 
1071 
Cervicalis ascendens muscle, 406 
Cervico-facial nerve, 736 
Cervix cornu posterioris, 659 
uteri, 981 
Chambers of the eye, 816 
Check ligaments, 310 
Cheek, muscles of, 377 
Cheeks, structure of, 840 
Chest, landmarks of, 1034 
muscles of front, 427 
of side, 430 
Chiasma, or optic commissure, 
717 
Chondro-glossus muscle, 390, 391 
Chondro-sternal ligaments, 315 
Chondro-xiphoid ligament, 317 
Chorda dorsalis, 106, 114 
tympani nerve, 734, 831 
Chordae tendineae, of right ven- 
tricle, 910 
of left ventricle, 912 
vocales, 923, 924 
Willisii, 619 
Chorion, 110 
Choroidal fissure, 121 
Choroid arteries, anterior, 533 
posterior, 549 
coat of eye, 809 
plexus of lateral ventricle, 694 
of fourth ventricle, 714 
of third ventricle, 699 
veins of brain, 619 
Chyle, 40 
Chyli receptaculum, 638 
Cilia, or eyelashes, 821 
Ciliary arteries, 532, 819 
ganglion, 723 
ligament, 812 
muscle, 812 
nerves, long, 722 
short, 722 
processes of eye, 810 
Circle of Willis, 550 
Circular sinus, 621 
Circulation of blood in adult, 907 
in foetus, 915 
Circumduction, 300 
Circumferential fibro-carti lage, 
53 
Circumflex artery of arm, ante- 
rior, 557 
posterior, 557 
of thigh, external, 598 
internal, 599 
iliac artery, 593 
superficial, 598 
vein, 631 
superficial, 630 
nerve, 756 
Circumflexus palati muscle, 394 
Claustrum, 694 
Clavicle, 229 
development of, 232 
fracture of, 457 
landmarks of, 1056 
[relation of, to arm and trunk, 
229] 
Clavicular nerves, 751 
Cleft palate, 397 
Clinoid processes, anterior, 179 
middle, 176 
posterior, 177 
Clitoris, 977 
fraenum of, 976 
lymphatics of, 648 
Clitoris- 
muscles of, 976, 1015 
prepuce of, 976 
Clivus Blumenbachii, 177 
Cloaca, 137 
Coccygeal artery, 590 
gland, 582 
nerves, 775 
Coccygeus muscle, 1018 
Coccyx, 157 
development of, 158 
Cochlea, 833 
aqueduct of, 174 
arteries of, 838 
central axis of, 833 
cupola of, 833 
denticulate lamina of, 835 
infundibulum of, 833 
lamina spiralis of, 834 
nerves of, 838 
scalae of, 834 
spiral canal of, 833 
veins of, 838 
Cochlear artery, 838 
nerve, 838 
Cochleariform process, 175, 828 
Cochlearis muscle, 835 
Coeliac axis, 574 
plexus, 794 
Colica dextra artery, 579 
media, 579 
sinistra, 579 
Collateral circulation. See Sur- 
gical Anatomy of each Ar- 
tery. 
fibres of cerebrum, 707 
fissure, 679 
Collecting tubes of kidney, 948 
Colles's fracture, 461 
Colon, 883 
Colostrum corpuscles, 989 
Colotomy, landmarks for, 1046 
Columella cochleae, 833 
Columnae carneae of left ventricle, 
912 
of right ventricle, 910 
papillares, 910, 913 
Columna nasi, 802 
Column of Goll, 658 
posterior vesicular, of spinal 
cord, 660 
Columns of abdominal ring, 993 
of medulla oblongata, 667 
of spinal cord, 655 
of vagina, 980 
Comes nervi ischiadici artery, 590 
phrenici artery, 551 
Commissura, simplex, of cerebel- 
lum, 709 
brevis, of cerebellum, 710 
Commissures of flocculus, 710 
optic, 717 
of brain, anterior, 701 
middle or soft, 701 
posterior, 701 
of spinal cord, gray, 656 
white, 656 
Common ligaments of vertebrae, 
302, 303 
Communicans noni nerve, 752 
peronei, 782 
Communicating artery of brain, 
anterior, 534 
posterior, 534 
from dorsalis pedis, 606 
Communicating artery from ul- 
nar, 569 
Compact tissue of bone, 54, 141 
Complexus muscle, 408 
Compressor narium minor, 374 
nasi, 374 
sacculi laryngis, 928 
urethrae, 1*017 
Conarium, 7 02 
Concentric corpuscles of thymus, 
942 
Conception, where effected, 101 
Concha, 823 
Condyles of bones. See Bones. 
Condyloid foramina, 162 
fossae, 162 
process, 200 
veins, posterior, 617, 620 
Congenital fissures in cranium, 
184 
hernia, 999 
Conglobate glands, 638 
Coni vasculosi, 971 
Conjoined tendon of internal ob- 
lique and transversalis, 
414, 994 
Conjunctiva, 821 
Connecting fibro-cartilages, 53 
Connective tissue, 45 
development of, 48 
Conoid ligament, 324 
Constrictor inferior muscle, 392 
medius, 393 
superior, 393 
isthmi faucium, 396 
urethrae, 1017 
Contractile-fibre cells, 67 
Conus arteriosus, 909 
[Convolution, Broca's, 676] 
of corpus callosum, 679 
Convolutions of cerebrum, struc- 
ture of, 703 
Coraco-acromial ligament, 326 
Coraco-brachialis muscle, 436 
Coraco-clavicular ligament, 324 
Coraco-humeral ligament, 327 
Coracoid ligament, 326 
process, 236 
fracture of, 458 
Cord, spermatic, 968 
umbilical, 113 
[ventricle of, 656, 661, 667] 
Cordiform tendon of diaphragm, 
424 
Corium of skin, 90 
of tongue, 799 
Cornea, 807 
Corneal corpuscles, 808 
spaces, 808 
Cornicula laryngis, 921 
Cornu Ammonis, 696 
Cornua Of the coccyx, 157 
of hyoid bone, 219 
of the sacrum, 154 
of thyroid cartilage, 920 
Corona glandis, 964 
radiata, 706 
Coronal suture, 203 
Coronaria ventriculi artery, 574 
Coronary arteries of lip, 518 
of heart, 507 
peculiarities, 508 
ligament of liver, 890 
ligaments of knee, 350 
plexus, anterior, 793 1072 
INDEX. 
Coronary plexus- 
posterior, 793 
sinus, 636 
opening of, 908 
valve, 908 
Coronoid depression, 241 
process of jaw, 200 
of ulna, 243 
fracture of, 459 
Corpora albicantia, 689 
Arantii, 911, 912 
mammillaria, 689 
cavernosa penis, 964 
crura of, 964 
cavernosa clitoridis, 977 
geniculata, 700, 706 
olivaria, 666 
pyramidalia, 666 
quadrigemina, 702 
restiformia, 666 
striata, 693 
Corpus callosum, 691, 707 
convolution of, 679 
genu of, 691 
peduncles of, 692 
ventricle of, 691 
dentatum of cerebellum, 710 
of olivary body, 667 
fimbriatum, 695 
Highmorianum, 970 
luteum, 987 
spongiosum, 966 
Corpus cavernosum, artery of, 589 
dentatum, 667 
Corpuscles, blood-, 36 
development of, 125 
Malpighian, of kidney, 946 
of spleen, 902 
Corrugator supercilii muscle, 370 
Cortex of cerebrum, 703 
of cerebellum, 711 
Corti, membrane of, 835 
organ of, 835 
rods of, 836 
(Cortical arterial system of brain, 
534, 537] 
arches, 946 
columns, 946 
substance of brain, 703 
of kidney, 946 
of suprarenal capsules, 953 
of teeth, 845 
Costal cartilages, 52, 228 
connection with ribs, 317 
Costo-chondral articulation, 317 
Costo-clavicular ligament, 323 
Costo-colic ligament, 869 
Costo-coracoid fascia, 429 
Costo-transverse articulations, 314 
Costo-vertebral articulations, 312 
Costal-vertebral ligaments, 313 
Chondro-xiphoid ligaments, 317 
Cotunnius, nerve of, 726 
Cotyloid cavity, 265 
ligament, 344 
notch, 265 
Coverings of direct inguinal her- 
nia, 999 
of femoral hernia, 1011 
of oblique, 998 
of testis, 969 
Cowper's glands, 963, 1017 
Cranial bones, 160 
articulations of, 203 
fossa1, 205 
Cranial nerves, 715 
first pair, 716 
second, 717 
third, 718 
fourth, 719 
fifth, 719 
sixth, 731 
seventh, 732 
eighth, 736 
ninth, 736 
tenth, 738 
eleventh, 741 
twelfth, 742 
development of, 120 
sutures, 202 
Cranium, 160 
congenital fissures in, 184 
development of, 183 
lymphatics of, 641 
Cremaster muscle, 994 
formation of, 995 
Cremasteric artery, 593 
fascia, 995 
Crescents of Gianuzzi, 855 
Crest, frontal, 168 
of ilium, 261 
lachrymal, 191 
nasal, 185 
occipital, 160 
internal, 163 
turbinated, of palate, 194 
of the superior maxillary, 
187 
of pubes, 265 
of tibia, 280 
Cribriform fascia, 1001 
plate of ethmoid, 181 
Crico-arytienoideus lateralis mus- 
cle, 925 
posticus muscle, 924 
Crico-thyroid artery, 515 
membrane, 922 
muscle, 924 
Cricoid cartilage, 920 
landmarks of, 1032 
Crista galli, 181, 206 
pubis, 265 
vestibuli, 832 
Crochet of uncinate gyrus, 680, 
708 
Cross pyramidal fasciculus, 658 
Crown of a tooth, 841 
Crucial anastomosis, 599 
ligaments of knee, 349 
Crura cerebri, 689 
cerebelli, 710 
of clitoris, 977 
of corpora cavernosa, 964 
of diaphragm, 424 
of fornix, 699 
Crural arch, 993, 1004 
deep, 1005 
canal, 1006 
nerve, anterior, 773 
ring, 1007 
sheath, 1005 
septum, 1008 
Crureus muscle, 468 
Crus penis, 964 
Crusta petrosa of teeth, 845 
of crus cerebri, 690, 707 
Crypts of Lieberkuhn, 879 
Crystalline lens, 817 
Crystals, blood-, 39 
Cuboid bone, 287 
Cuneate lobe, 680 
fasciculus, 658 
Cuneiform bone, hand, 252 
foot, external, 290 
internal, 289 
middle, 290 
cartilages, 921 
Cuneus, 680 
Cupola of cochlea, 833 
Curling, Mr., on the descent of 
the testes, 974 
Curvatures of the spine, 159 
Cuspidate teeth, 841 
Cutaneous branches of accessory 
obturator, 773 
of anterior tibial nerve, 782 
of cervical plexus, 750 
of circumflex, 756 
of dorsal nerve of penis, 779 
of dorsal nerves, 764 
of external popliteal, 782 
internal, 780 
of inferior hemorrhoidal 
nerve, 778 
of ilio-hypogastric, 770 
of ilio-inguinal, 770 
of intercostal nerves, 766 
of lesser sciatic nerve, 779 
of lumbar nerves, 767 
of median, 759 
of musculo-spiral, 762 
of ulnar nerve, 761 
of arm, musculo-cutaneous, 
756 
internal, 756 
lesser internal, 757 
of buttock and thigh, 779 
of inguinal region, 1001 
of ischio-rectal region, 1011 
from obturator, 771 
of thigh, external, 770 
internal, 774 
middle, 773 
of patella, 774 
of perineal nerve, 779 
plantar nerve, 781 
of posterior tibial, 781 
of radial, 763 
of sacral nerves, 775 
of ulnar, 761 
Cuticle of skin, 89 
Cuticula dentis, 847 
Cutis vera, 90 
Cuvier, ducts of, 129 
Cystic artery, 676 
duct, 896 
valve of, 896 
plexus of nerves, 794 
veins, 636 
D. 
Dartos, 967 
Decussation of optic nerves, 717 
of pyramids, 666 
Decidua, 111 
serotina, 112 
reflexa, 112 
vera, 112 
Deciduous teeth, 840 
Deep crural arch, 1005 
palmar arch, 563 
perineal fascia, 1015 
Deferent artery, 586 
Deglutition, actions of, 394, 396 
Deltoid aponeurosis, 432 INDEX. 
1073 
Deltoid muscle, 432 
Demilunes of Heidenhain, 855 
Demours, membrane of, 807 
Dens sapientise, 843 
Dental artery, inferior, 523 
posterior, 524 
canal, anterior, 187 
inferior, 199 
posterior, 187 
groove, 846, 848 
nerves, anterior, 725 
inferior, 729 
middle, 725 
posterior, 724 
ridges, 846 
sacs, 848 
tubuli, 844 
vein, inferior, 614 
Dentate fissure, 679 
Denticulate lamina of cochlea, 
834 
Dentinal sac, 847 
Dentine, 844 
formation of, 847 
Depressions of Pacchionian 
bodies, 165 
Depressor alae nasi, 374 
anguli oris, 376 
epiglottidis, 926 
labii inferioris, 396 
Derma, or true skin, 90 
Descemet, membrane of, 807 
Descendens noni nerve, 743 
Descending aorta, 569 
colon, 883 
Descent of testicle, 974 
Development of atlas, 151 
axis, 152 
alimentary canal and its ap- 
pendages, 130 
arteries, 126 
bone, 59 
carpus, 259 
clavicle, 232 
coccyx, 158 
cranium, 115, 183 
ear, 122 
ethmoid, 183 
eye, 121 
face, 115 
femur, 276 
fibula, 283 
foot, 294 
frontal bone, 169 
genital organs, 135 
hand, 259 
heart, 124 
humerus, 241 
hyoid bone, 220 
inferior turbinated bone, 196 
lachrymal bone, 192 
lens, 121 
lower jaw, 201 
lumbar vertebrae, 152 
malar bone, 193 ( 
mammae, 123 
metacarpus, 259 
metatarsus, 294 
muscles, 124 
nasal bone, 185 
nervous centres, 118 
nose, 117 
occipital bone, 164 
os innominatum, 266 
Development of- 
palate, 117 
palate bone, 195 
parietal bone, 166 
patella, 278 
permanent teeth, 848 
phalanges of hand, 259 
of foot, 294 
radius, 249 
ribs, 228 
sacrum, 156 
scapula, 236 
seventh cervical, 152 
skin, 123 
sphenoid, 180 
spine, 114 
sternum, 223 
superior maxillary bone, 190 
tarsus, 294 
temporary teeth, 846 
temporal bone, 175 
tibia, 281 
ulna, 247 
veins, 128 
vertebrae, 150 
vomer, 197 
Wormian, 184 
Development of Organs, Chron- 
ological Table of, 139 
Diameters of pelvis, 268 
Diaphragm, 422 
development of, 132 
lymphatics of, 650 
Diaphysis, 63, [141] 
Diarthrosis, 298 
rotatoria, 300 
Digastric muscle, 388 
fossa, 172 
lobe of cerebellum, 710 
nerve, from facial, 734 
Digestion, organs of, 839 
Digital arteries from ulnar, 569 
from plantar, 610 
cavity of lateral ventricle, 692 
fossa, 271 
nerves, from median, 759 
from radial, 763 
from ulnar, 762 
of foot, 782 
Dilatator naris, anterior, 374 
posterior, 374 
Diploe, 142 
veins of, 617 
Direct inguinal hernia, 999 
course of, 999 
coverings of, 999 
incomplete, 1000 
pyramidal fasciculus, 658 
Discus proligerus, 986 
Disks, blood, 36 
development of, 125 
Dissection of abdominal muscles, 
412 
arch of aorta, 501 
arm, 435 
auricular region, 369 
axilla, 426 
back, 399 
epicranial region, 366 
eye, 808 
femoral hernia, 1000 
face, 369 
foot, 488 
forearm, 439 
gluteal region, 472 
Dissection of- 
hand, 449 
heart, left auricle, 911 
left ventricle, 912 
right auricle, 907 
right ventricle, 909 
hernia, femoral, 1000 
inguinal, 991 
iliac region, 462 
inferior maxillary region, 376 
infrahyoid region, 386 
inguinal hernia, 991 
intermaxillary region, 377 
ischio-rectal region, 1010 
leg, 479 
lingual region, 390 
neck, 382 
orbit, 371 
palatal region, 394 
palm of hand, 449 
palpebral region, 369 
pancreas, 897 
pectoral region, 426 
perineum, 1010, 1016 
pharynx, 392 
pterygoid muscles, 380 
radial region, 444 
scalp, 366 
sole of foot, 488 
spinal cord and membranes, 
652 
suprahyoid region, 388 
temporal muscle, 379 
thigh, front of, 465 
back of, 477 
inner side of, 470 
Dorsal artery of penis, 589 
nerve of penis, 779 
nerves, 764 
peculiar, 767 
vein of penis, 632 
vertebrae, 147 
peculiar, 149 
Dorsales pollicis arteries, 564 
Dorsalis hallucis artery, 606 
indicis, 564 
linguae, 515 
pedis, 605 
branches of, 606 
peculiarities of, 606 
surgical anatomy of, 606 
scapulae, 556 
Dorsi-lumbar nerve, 767 
Dorsi-spinal veins, 628 
Dorsum of scapula, 233 
ephippii or sellae, 176 
Douglas, pouch of, 981 
semilunar fold of, 418 
Ducts or duct, of Bartholine, 854 
biliary, 896 
of Cowper's glands, 964 
of Cuvier, 129 
cystic, 896 
ejaculatory, 973 
of Gartner, 136 
galactophorous, 989 
hepatic, 895, 896 
of kidney, 951 
lactiferous, 989 
of liver, 895 
lymphatic, right, 640 
nasal, 822 
landmarks of, 1029 
of pancreas, 898 
parotid, 853 1074 
INDEX. 
Ducts or duct of- 
Rivini, 854 
seminal, 971 
Stenson's, 853 
thoracic, 639 
Wharton's, 853 
Ductless glands: 
spleen, 899 
suprarenal capsule, 953 
thyroid, 939 
thymus, 941 
Ductus arteriosus, 915 
how obliterated in foetus, 918 
communis choledochus, 896 
pancreaticus minor, 898 
Rivini, 854 
venosus, 916 
how obliterated, 918 
Duodenal glands, 87 9 
Duodenum, 874 
vessels and nerves of, 876 
Dura mater of brain, 661 
arteries of, 662 
nerves of, 662 
processes of, 662 
veins of, 662 
of cord, 652 
peculiarities of, 652 
E. 
Ear, 823 
arteries of, 826, 831, 838 
[artistic value of, 825] 
auditory canal, 825 
cochlea, $33 
internal, or labyrinth, 832 
membranous labyrinth, 837 
muscles of auricle, 824 
of tympanum, 830 
ossicula of, 829 
pinna or auricle of, 823 
semicircular canals, 832 
tympanum, 826 
vestibule, 832 
Earthy constituents of bone, 59 
Eighth nerve, 736 
Ejaculatory ducts, 973 
Elastic lamina of cornea, 808 
[Elbow, angle at, 242] 
anastomoses around, 562 
bend of, 559 
joint, 329 
landmarks of, 1058 
vessels and nerves of, 331 
[Election, triangle of, 526] 
[Electrical points for muscles, 
496] 
Eleventh nerve, 741 
Embryo, first rudiments of, 103 
Eminence of aquseductus Fal- 
lopii, 827 
canine, 186 
frontal, 167 
ilio-pectineal, 265 
nasal, 169 
parietal, 164 
Eminences and depressions of 
bones, 142 
Eminentia articularis, 171 
collateralis, 693 
Enamel epithelium, 846, 847 
of teeth, 845 
formation of, 846 
germ, 846 
Enamel- 
organ, neck of, 846 
rods, 845 
Enarthrosis, 299 
[End-arteries, 535] 
End-bulbs of Krause, 75 
End-plates, motorial, of Kiihne, 
75 
Endocardium, 912 
Endolymph, 838 
Endothelium, 44 
Ensiform appendix, 222 
Epencephalon, 119 
Ependyma, 692 
Epiblast, 102 
Epidermis, structure of, 89 
development of, 123 
Epididymis, 969 
development of, 135 
Epigastric artery, deep, 593 
peculiarities, 593 
relation to femoral ring, 
1007 
with internal ring, 996 
superficial, 597 
superior, 552 
plexus, 793 
region, 860 
vein, 631 
superficial, 630 
Epiglottic glands, 927 
Epiglottis, 921 
Epiphyses, 63, 142 
[Epiphysis, 141] 
cerebri, 702 
Epipteric bone, 184 
Epithelium, ciliated, 43 
columnar, 43 
■ pavement, 42 
spheroidal or glandular, 43. 
See Various Organs. 
[Epoophoron, 136, 985] 
Erectile tissue, its structure, 965 
of clitoris, 977 
of penis, 965 
Erector clitoridis, 977, 1015 
penis, 1014 
spinae, 406 
Eruption of the teeth, 849 
Ethmo-sphenoidal suture, 206 
Ethmoid bone, 181 
articulations of, 183 
cribriform plate of, 181 
development of, 183 
lateral masses of, 182 
os planum of, 182 
perpendicular plate of, 181 
unciform process of, 182 
Ethmoidal artery, 532 
canal, anterior, 169 
posterior, 169 
cells, 182 
crest, 177 
notch, 169, 182 
process of inferior turbinated, 
196 
spine, 176 
Ethmoido-frontal suture, 206 
Eustachian tube, 175, 828 
valve, 908 
in foetal heart, 915 
Examination per vaginam, 1063 
Expiration, muscles of, 421 
[Expression, muscles of, 365] 
Extensor coccygis, 410 
Extensor brevis digitorum mus- 
cle, 489 
carpi radialis brevior, 445 
longior, 405 
carpi ulnaris, 446 
communis digitorum (hand), 
. 446 
indicis, 448 
longus digitorum (foot), 480 
minimi digiti, 446 
ossis metacarpi pollicis, 447 
primi internodii pollicis, 447 
proprius pollicis, 480 
secundi internodii pollicis, 
448 
External abdominal ring, 413, 
997 
annular ligament, 488 
capsule, 694 
inguinal hernia, 999 
orbital foramina, 178 
pterygoid plate, 179 
spermatic fascia, 414, 993 
sphincter, 1014 
Eye, 805 
appendages of, 819 
chambers of, 816 
ciliary ligament, 812 
muscle, 812 
processes of, 810 
humors of, 816 
aqueous, 816 
crystalline lens, 817 
vitreous, 817 
landmarks of, 1028 
membrana pupillaris, 812 
choroid, 809 
conjunctiva, 821 
cornea, 807 
hyaloid membrane, 817 
iris, 810 
Jacob's, 815 
retina, 812 
sclerotic, 806 
pupil of, 810 
tunics of, 806 
uvea of, 811 
vessels of globe of, 819 
elastic lamina of cornea, 808 
Eyeball, muscles of, 371 
nerves of, 819 
vessels of, 819 
Eyebrows, 819 
Eyelashes, 821 
Eyelids, 819 
cartilages of, 820 
Meibomian glands of, 820 
muscles of, 370 
tarsal ligament of, 820 
Eye-teeth, 841 
F. 
Face, arteries of, 516 
bones of, 160, 185 
lymphatics of, 641 
muscles of, 370 
nerves of, 735 
veins of, 613 
Facial artery, 516 
surgical anatomy of, 519 
transverse, 521 
bones, 185 
nerve, 732 
vein. 613 INDEX. 
1075 
Falciform process of fascia lata, 
1002 
ligament of liver, 889 
Fallopian tubes, 984 
development of, 135 , 
fimbriated extremity of, 984 
lymphatics of, 648 
nerves of, 988 
structure of, 985 
vessels of, 988 
False corpora lutea, 987 
ligaments of bladder, 957 
pelvis, 268 
ribs, 224 
Falx cerebelli, 663 
cerebri, 662 
Fangs of teeth, 841 
Fascia, anal, 1022 
Fasciae, general description of, 
364 
of arm, 435 
of cranial region, 366 
cervical, deep, 383 
superficial, 382 
costo-coracoid, 429 
cremasteric, 995 
cribriform, 1001 
deep, 365 
dentata, 697 
dorsal, of foot, 489 
fibro-areolar, its structure, 364 
iliac, 462 
infundibuliform, 996 
intercolumnar, 414, 993 
intercostal, 420 
intermuscular, of arm, 436 
of foot, 488 
ischio-rectal, 1022 
lata, 465, 1001 
falciform process of, 1002 
iliac portion, 466, 1001 
pubic portion, 466, 1002 
of leg, 479 
deep transverse, 484 
himborum, 416 
obturator, 1022 
of mamma,*426 
of neck, 382 
palmar, 450 
pelvic, 1021'- 
perineal, deep, 1015 
superficial, 1013 
plantar, 489 
of foot, 488 
of forearm, 439 
of hand, 450 
propria of spermatic cord, 968 
of femoral hernia, 1009 
recto-vesical, 1022 
spermatic, 414, 993 
superficial, 364 
of inguinal region, 991 
of ischio-rectal region, 1010 
of thigh, 465 
temporal, 379 
of thigh, deep, 465 
superficial, 465 
of thorax, 419, 426 
transversalis, 996 
visceral layer of pelvic, 1022 
Fasciculi teretes, 667, 713 
Fasciculus of Tiirck, 658 
unciformis, 688 
Fat, 50 
Fauces, isthmus of, 851 
Features as landmarks, 1031 
Fecundation of ovum, 101 
Female organs of generation : 
bulbi vestibuli, 978 
caruncula? myrtiformes, 978 ] 
clitoris, 977 
development of, 135 
fossa navicularis, 976 
fraenulum pudendi, 976 
glands of fiartholine, 978 
hymen, 977 
labia majora, 976 
minora, 976 
nympha?, 976 
prseputium clitoridis, 976 
uterus, 980 
vagina, 979 
vestibule, 977 
Femoral artery, 594 
branches of, 597 
peculiarities of, 596 
surgical anatomy of, 596 
deep, 598 
canal, 1006 
variation in size of, accord- 
ing to position of limb, 
1008 
hernia, complete, 1009 
coverings of, 1008 
descent of, 1008 
dissection of, 1001 
incomplete, 1009 
seat of stricture, 1009 
surgical anatomy of, 1000 
ligament (Hey's) 1002 
position of surrounding parts, 
. 1007 
region, muscles of anterior, 465 
internal, 470 
posterior, 477 
ring, 1007 
sheath, 1004 
vein, 631 
relation of femoral ring, 
1007 
Femur, 270 
articulations of, 276 
attachment of muscles to, 27 6 
below trochanters, 494 
condyles of, 274 
development of, 276 
fracture of, above condyles, 495 
head of, 271 
neck of, 271 
fracture of, 494 
structure of, 275 
trochanters of, 271 
Fenestra ovalis, 826 
rotunda, 827, 834 
Fenestrated membrane of Henle, 
79 
Ferrein, pyramids of, 948 
Fibrae arciformes, 666, 667 
trans versse, 713 
Fibre-cells, contractile, 67 
[Fibres of Gerdy, 451] 
of Muller, 815 
of muscle, 362 
of nerves, 69 
Fibro-cartilage, 52 
interarticular, 52 
connecting, circumferential, 
and stratiform, 53 
I Fibro-cartilages, acromio-clavic- 
ular, 324 
Fibro-cartilages- 
intercoccygean, 321 
intervertebral, 303 
of knee, 350 
of lower jaw, 311 
pubic, 321 
radio-ulnar, 334 
sacro-coccygean, 321 
sterno-clavicular, 323 
Fibrous cartilage, 52 
nervous matter, 69 
rings of heart, 913 
tissue, white, 45 
yellow, 46 
Fibro-serous membranes, 95 
Fibula, 281 
articulations of, 283 
attachment of muscles to, 283 
development of, 283 
fracture of, with dislocation erf 
the tibia, 495 
landmarks of, 1053 
Fibular region, muscles of, 486 
Fifth nerve, 719 
ventricle of brain, 697 
Fillet, 667 
Filum terminale of cord, 654 
Fimbriae of Fallopian tube, 984 
First nerve, 716 
Fissure, auricular, 175 
for gall-bladder, 891 
for vena cava, 891 
Glaserian, 171, 826 
horizontal, of cerebellum, 710 
of ductus venosus, 891 
longitudinal, of cerebrum, 672, 
687 
of liver, 891 
[of Bichat, 675, 697] 
of cerebrum, 697 
of liver, 891 
of lung, 935 
of medulla oblongata, 665 
[of Rolando, 675, 685] 
of spinal cord, 655 
[of Sylvius, 675, 686] 
[parieto-occipital, 676, 687] 
portal, 891 
pterygo-maxillary, 212 
spheno-maxillary, 212 
sphenoidal, 178 
Sylvian, 675, 688 
transverse, of liver, 891 
umbilical, 891 
Fissures, congenital, in cranium, 
184 
calcarine, 678 
collateral, 679 
calloso-marginal, 678 
dentate, 679 
intraparietal, 676 
parallel, 677 
parieto-occipital, 678 
precentral, 676 
Rolando, 675 
Sylvius, 675, 688 
Flat bones, 141 
Flexor accessorius muscle, 491 
brevis digitorum, 490 
brevis minimi digiti (hand), 
455 
(foot), 492 
brevis pollicis (hand), 454 
(foot), 492 
carpi radialis, 440 1076 
INDEX. 
Flexor carpi ulnaris, 441 
digitorum sublimis, 441 
digitorum profundus, 442 
longus digitorum, 485 
longus pollicis (hand), 442 
(foot), 484 
ossis metacarpi pollicis, 453 
Floating ribs, 225 
Flocculus, 710 
Foetus, circulation in, 916 
Eustachian valve in, 915 
foramen ovale in, 126, 915 
liver of, distribution of its ves- 
sels, 916 
ovaries in, 135 
vascular system in, peculiari- 
ties, 915 
Folds, aryteno-epiglottidean, 923 
genital, 138 
recto-uterine, 981 
recto-vesical, 957 
vesico-uterine, 981 
Follicle of hair, 93 
of intestine, 879 
Follicles, sebaceous, 94 
Fontana, spaces of, 811 
Fontanelles, 163,184 
Foot, arteries of, 605, 608 
bones of, 284 
development of, 294 
dorsum, muscles of, 489 
fascia of, 489 
ligaments of, 487 
sole of, muscles of, 489 
fascia of, 488 
nerves of, 781 
veins of, 630 
[Foot-sole, imprint of, 294] 
Foramen caecum of frontal bone, 
168, 206 
of medulla oblongata, 665 
of tongue, 799 
carotid, 174 
condyloid, 162 
dental inferior, 199 
ethmoidal, 206 
incisive, 208 
infraorbital, 186 
intervertebral, 159 
jugular, 207 
lacerum anterius, 179, 206 
magnum, 161 
mastoid, 171 
medium, 207 
mental, 198 
obturator, 266 
of Majendie, 653 
of Monro, 694, 702 
of sphenoid, 179, 206 
of Winslow, 866 
optic, 176, 206 
ovale of heart, 915 
of sphenoid, 178 
palatine, anterior, 190, 207 
posterior, 194, 208 
parietal, 164 
posterius, 207 
pterygo-palatine, 178 
rotundum, 178, 207 
sacro-sciatic, 263, 320 
of Scarpa, 190, 208 
of Sommerring, 813 
spheno-palatine, 195, 217 
[spinal, 144] 
spinosum, 178, 207 
Foramen of Stenson, 190, 208 
sternal, 222 
stylo-mastoid, 174 
supraorbital, 167 
thyroid, 266 
vertebral. 144 
Vesalii, 178, 207 
Foramina, sacral, 153 
of diaphragm, 424 
external orbital, 178 
of face, landmarks of, 1027 
malar, 192 
olfactory, 181 
Thebesii, 637, 908 
Forearm, arteries of, 561 
bones of, 242 
fascia of, 439 
landmarks of, 1060 
lymphatics of, 644 
muscles of, 439 
nerves of, 759 
veins of, 624 
[Forehead, wrinkles of, 368, 371] 
Form of bones, 141 
Fornix, 698 
bulbs of, 689 
conjunctivae, 821 
crura of, 699 
Fossa of antihelix, 823 
canine, 186 
condyloid, 162 
cystis fellese, 891 
digastric, 172 
digital, 271 
glenoid, 171 
of helix, 823 
iliac, 261 
incisive, 186, 198 
infra- and supraspinous, 233 
innominata, 823 
ischio-rectal, 1010 
jugular, 175 
lachrymal, 169 
myrtiform, 186 
navicularis of urethra, 960 
of vulva, 976 
occipital, 162 
olfactory of foetus, 123 
ovalis, 908 
palatine, anterior, 189 
pituitary, 176 
pterygoid, of sphenoid, 179 
of lower jaw, 199 
scaphoid, 179 
scaphoidea. 823 
sigmoidea, 172 
spheno-maxillary, 212 
of skull, anterior, 206 
middle, 206 
posterior, 207 
sublingual, 199 
submaxillary, 199 
subscapular, 233 
temporal, 211 
trochanteric, 271 
zygomatic, 212 
Fossae, nasal, 215, 803 
of skull, 206 
Fourchette, 976 
Fourth nerve, 719 
ventricle, 712 
Fovea, anterior of fourth ven- 
tricle, 713 
centralis retinae, 813 
Fovea hemispherica, 832 
posterior of fourth ventricle, 
713 
semi-elliptica, 832 
Fracture of acromion process, 458 
centre of clavicle, 457 
acromial end of, 458 
coracoid process, 458 
coronoid process of ulna, 459 
femur above condyles, 495 
below trochanters, 494 
fibula, with dislocation of 
tibia, 495 
humerus, anatomical neck, 458 
shaft of, 458 
surgical neck, 458 
neck of femur, 494 
olecranon process, 459 
patella, 495 
Pott's, 495 
radius, 460 
lower end of, 461 
neck of, 459 
shaft of, 460 
and ulna, 460 
sternal end of clavicle, 458 
tibia, shaft of, 495 
ulna, shaft of, 460 
Frsena of ileo-csecal valve, 883 
Fraenulum pudendi, 976 
of Vieussens' valve, 703 
Fraenum clitoridis, 977 
labii superioris et inferioris, 
839 
linguae, 799 
praeputii, 964 
Frontal artery, 532 
bone, 166 
articulations of, 170 
attachment of muscles to, 
170 
development of, 169 
structure of, 169 
crest, 168 
eminence, 167 
lobe, 676 
nerve, 721 
process of malar, 192 
I sinuses, 169 
landmarks of, 1026 
suture, 166, 170, 203 
vein, 613 
Fronto-malar suture, 215 
Fronto-nasal process, 117 
Fronto-sphenoidal suture, 206, 
215 
Fundamental fasciculus, 658 
Fundus of bladder, 957 
of uterus, 981 
Funiculi graciles, 666 
of nerve, 73 
I Funiculus of Rolando, 668 
Furrow, auriculo-ventricular, 907 
digital, 1061 
genital, 138 
interventricular, 907 
Furrowed band of cerebellum, 
710 
G. 
Galactophorous ducts, 989 
Galen, veins of, 618, 699 
Gall-bladder, 895 INDEX. 
1077 
Gall-bladder- 
fissure for, 891 
structure of, 896 
[surgery of, 896] 
valve of, 896 
Ganglion corpuscles, 78 
Ganglion or ganglia, general 
anatomy of, 77 
of Andersch, 737 
Arnold's, 729 
cardiac, 793 
carotid, 789 
cephalic, 723 
cervical, inferior, 791 
middle, 790 
superior, 787 
ciliary, 723 
on circumflex nerve, 756 
diaphragmatic, 794 
on facial nerve, 733 
of fifth nerve, 722 
Gasserian, 720 
of glosso-pharyngeal, 737 
impar, 783, 792 
intercarotid, 790 
on posterior interosseous 
nerve, 764 
jugular, 737 
lenticular, 723 
lingual, 790 
lumbar, 792 
Meckel's, 725 
mesenteric, 796 
ophthalmic, 722 
otic, 729 
petrous, 757 
pharyngeal, 790 
of pneumogastric, 739 
of portio dura, 733 
of Ribes, 784 
of root of vagus, 739 
sacral, 792 
semilunar, of abdomen, 793 
spheno-palatine, 724 
of spinal nerves, 745 
spirale, 835 
submaxillary, 730 
suprarenal, 794 
of sympathetic nerve, 784 
temporal, 790 
thoracic, 791 
thyroid, 790 
of trunk of vagus, 739 
of Wrisberg, 793 
[Ganglionic arterial system of 
brain, 536] 
branch of nasal nerve, 722 
Gartner, duct of, 136 
Gases of the blood, 39 
Gasserian ganglion, 720 
depression for, 174 
Gastric arteries (vasa brevia), 
577 
artery, 574 
follicles, 872 
nerves from vagus, 741 
plexus, 795 
vein, 635 
Gastro-colic omentum, 867 
Gastro-duodenal artery, 575 
plexus, 795 
Gastro-epiploica dextra arterv, 
. 576 
sinistra, 577 
Gastro-epiploic plexus, 795 
Gastro-epiploic veins, 635 
Gastro-hepatic omentum, 867 
Gastro-phrenic ligament, 870 
Gastro-splenic omentum, 867 
Gastrocnemius muscle, 482 
Gelatinous connective tissue, 48 
nerve-fibres, 71 
Gemellus inferior muscle, 476 
superior, 476 
Generative organs, development 
of, 135 
female, 976 
male, 962 
Genial tubercles, 199 
Genio-hyo-glossus muscle, 390 
Genio-hyoid muscle, 389 
Genital cord, 134 
folds, 138 
furrow, 138 
tubercle, 138 
Genito-crural nerve, 770 
Genu of the corpus callosum, 
691 
[Gerdy, fibres of, 451] 
Gerlach's nerve network, 659 
Germinal area, 102 
disk, 102 
spot, 100 
vesicle, 100 
Gimbernat's ligament, 413, 1004 
Ginglymus, 299 
Giraldos, organ of, 135 
[Girdle, pelvic, 259] 
[shoulder, 259] 
[Glabella, 684] 
of frontal bone, 168 
Gladiolus, 222 
Glands, ductless, 899 
spleen, 899 
suprarenal, 953 
thymus, 941 
thyroid, 939 
Glands, lymphatics, 87 
Gland or glands, secreting, 97 
accessory of parotid, 853 
arytenoid, 927 
of Bartholine, 978 
of biliary ducts, 897 
Brunner's, 879 
buccal, 840 
ceruminous, 826 
coccygeal, 582 
Cowper's, 963, 1017 
duodenal, 879 
epiglottic, 927 
gastric, 872 
of Havers, 297 
labial, 839 
lachrymal, 821 
of larynx, 927 
lingual, 800 
of Littre, 960 
of Luschka, 582 
mammary, 988 
Meibomian, 820 
molar, 840 
mucilaginous, of Havers, 297 
odoriferae, 964 
oesophageal, 858 
of Pacchioni, 619, 662 
palatine, 851, 856 
parotid, 852 
peptic, 872 
Peyer's, 880 
pharyngeal, 857 
Gland or glands- 
pineal, 702 
pituitary, 689 
prostate, 962 
salivary, 852 
sebaceous, 94 
solitary, 880 
sublingual, 854 
submaxillary, 853 
sudoriferous, 94 
suprarenal, 953 
thymus, 941 
thyroid, 939 
tracheal, 929 
of Tyson, 964 
uterine, 983 
of vulva, 978 
Glanduhe odoriferae, 964 
Pacchioni, 619, 662 
Glans penis, 964 
clitoridis, 977 
Glaserian fissure, 171, 826 
Glenoid cavity, 236 
fossa, 171 
ligament of shoulder, 327 
of phalanges, 341 
Gliding movement, 300 
Glisson's capsule, 867, 892 
Globules, blood-, 36 
development of, 125 
Globus major of epididymus, 971 
minor, 971 
Glosso-epiglottidean ligaments, 
921 
Glossso-pharyngeal nerve, 736 
Glottis, 923 
rima of, 923 
Gluteal artery, 591 
inferior, 590 
lymphatic glands, 645 
nerve, inferior, 780 
superior, 778 
region, lymphatics of, 646 
muscles of, 472 
veins, 632 
aponeurosis, 465 
Gluteus maximus muscle, 473 
medius, 474 
minimus, 474 
Gomphosis, 298 
[Gonion, 685] 
Graafian vesicles, 986 
membrana granulosa of, 
ovicapsule of, 986 
structure of, 986 
Gracilis muscle, 470 
Gray nervous substance, 68 
matter of cerebellum, 711 
of cerebrum, 703 
of fourth ventricle, 714 
of medulla oblongata, 669 
of spinal cord, 658 
Great omentum, 867 
sciatic nerve, 7 80 
Greater wings of sphenoid, 178 
Groin, 991 
cutaneous vessels and nerves 
of, 991 
landmarks of, 1049 
superficial fascia of, 991 
surgical anatomy of, 991 
Groove, auriculo-ventricular, 90V 
bicipital, 238 
cavernous, 177 
primitive dental, 846 1078 
INDEX. 
Groove- 
infraorbital, 187 
lachrymal, 187 
mylo-hyoid, 199 
nasal, 185 
occipital, 172 
optic, 176 
subclavian, 226 
Grooves in the radius, 249 
ventricular, 907 
Growth of bones, 62 
Gubernaculum testis, 974 
Gums, 840 
Gustatory nerve, 729 
Gyri operti, 678, 688 
Gyrus fornicatus, 679 
II. 
Heematoidin crystals, 39 
Haemin crystals, 39 
Haemoglobin crystals, 39 
Hair-cells of internal ear, 836 
Hairs, 92 
follicles, 93 
root-sheath, 92 
shaft, 93 
structure of, 93 
Ham, region of the, 600 
Hamstring tendons, surgical 
anatomy of, 479 
Hamular process of sphenoid, 
179 
of humerus, 240, note 
of lachrymal, 191 
Hand, arteries of, 566 
bones of, 250 
fascia of, 449 
landmarks of, 1061 
ligaments of, 336 
muscles of, 449 
nerves of, from median, 759 
from radial, 763 
from ulnar, 761 
veins of, 623 
Hard palate, 850 
Harmonia, 298 
Hasner, valve of, 822 
Havers, glands of, 297 
Haversian canals of bone, 56 
Head, lymphatics of, 640 
muscles of, 365 
veins of, 612 
Heart, 906 
annular fibres of auricles, 913 
arteries of, 507, 915 
circular fibres of, 913 
development of, 124 
endocardium, 912 
fibres of the auricles, 913 
of the ventricles, 913 
fibrous rings of, 913 
foetal relics in, 909 
infundibulum of, 909 
landmarks of, 1035 
left auricle, 911 
ventricle, 912 
looped fibres of auricles, 913 
lymphatics of, 650, 915 
muscular fibres of, 66 
structure of, 913 
nerves of, 740, 792, 915 
outline of, on chest-wall, 1035 
position of, 906 
right auricle, 907 
Heart- 
right ventricle, 909 
septum ventriculorum, 909 
size and weight, 906 
spiral fibres of, 914 
structure of, 913 
subdivision into cavities, 907 
valves of, landmarks, 1036 
veins of, 636 
vortex of, 914 
Heidenhain, demilunes of, 855 
Helicine arteries, 965 
Helicis major muscle, 824 
minor, 824 
Helicotrema of cochlea, 833 
Helix, 823 
fossa of, 823 
muscles of. 824 
process of, 823 
Hemorrhoidal artery, inferior, 
589 
middle, 586 
superior, 579 
nerve, inferior, 778 
plexus of nerves, 796 
veins, inferior, 632 
middle, 632 
superior, 634 
venous plexus, 632, 634 
Henle, looped tubes of, 947 
Hepatic artery, 574, 894 
cells, 893 
duct, 896 
plexus, 794 
veins, 634, 892, 894 
Hernia, congenital, 999 
descent of, 1008 
direct inguinal, 999 
dissection of, 1000 
femoral, coverings of, 1008 
[general remarks on, 997] 
infantile, 999 
inguinal, 991 
dissection of, 991 
oblique inguinal, 998 
scrotal, 998 
Hesselbach's triangle, 999 
Hey's ligament, 1002 
Hiatus Fallopii, 174 
Highmore, antrum of, 187 
Hilton's muscle, 926 
Hilum of kidney, 944 
of spleen, 899 
Hinge-joint, 299 
Hip-joint, 342 
muscles of, 472 
in relation with, 345 
Hippocampus major, 696 
minor, 693 
Horizontal plate of ethmoid, 181 
of palate, 193 
[Horner's muscle, 371, 822] 
Horny band of Tarin us, 694 
Huguier, canal of, 171 
Humerus, 237 
anatomical neck, fracture of, 
458 
articulations of, 242 
attachment of muscles to, 242 
development of, 241 
head of, 237 
landmarks of, 1057 
neck of, 238 
nutrient artery of, 561 
shaft, fracture of, 458 
Humerus- 
[surgical head, 237] 
surgical neck, fracture Oi, 458 
tuberosities of, greater and 
lesser, 238 
Humors of the eye, 816 
Hyaline cartilage, 51 
Hyaloid membrane of eye, 816 
Hydatid of Morgagni, 136 
Hymen, 977 
Hyo-epiglottic ligament, 922 
Hyo-glossal membrane, 801 
Hyo-glossus muscle, 390 
Hyoid artery of superior thy- 
roid, 514 
bone, 219 
attachment of muscles to, 220 
cornua of, 219 
development of, 220 
landmarks of, 1032 
branch of lingual artery, 515 
region, muscles of, infra-, 386 
supra-, 388 
Hypoblast, 102 
Hypochondriac regions, 860 
Hypogastric arteries in foetus, 
584, 916 
how obliterated, 918 
plexus, 796 
inferior, 796 
region, 860 
Hypoglossal nerve, 742 
Hypophysis cerebri, 689 
of pituitary body, 119 
I. 
Ileo-ccecal or ileo-colic valve, 
882 
Ileo-colic artery, 579 
Ileum, 876 
Iliac arteries, common, 582 
peculiarities, 583 
surgical anatomy of, 583 
external, 591 
surgical anatomy of, 592 
internal, 584 
at birth, 584 
peculiarity in the foetus, 
584 
surgical anatomy of, 585 
fascia, 462 
portion of fascia lata, 466 
fossa, 261 
lymphatic glands, 646 
region, muscles of, 462 
veins, common, 632 
peculiarities of, 632 
external, 631 
internal, 631 
Iliacus muscle, 464 
llio-costalis muscle, 406 
Ilio-femoral ligament, 343 
Ilio-hypogastric nerve, 769 
Ilio-inguinal nerve, 770 
Ilio-lumbar artery, 591 
ligament, 318 
vein, 632 
Ilio-pectineal eminence, 265 
Ilio-tibial band, 467 
Ilium, 261 
crest of, 261 
dorsum of, 261 
landmarks of, 1043 
spines, 261 INDEX. 
1079 
Ilium- 
venter of, 261 
Impressio colica, 892 
renalis, 892 
Incisive canal, 208 
foramina, 208 
fossa, 186, 198 
Incisor teeth, 841 
Incisura intertragica, 823 
cerebelli, 709 
Santorini, 825 
Incus, 829 
development of, 123 
ligament of, 830 
suspensory, 830 
Infantile hernia, 999 
Inferior dental artery, 523 
dental canal, 199 
[frontal sulcus, 676, 686] 
maxillary bone, 197 
landmarks of, 1028 
meatus of nose, 218 
occipital fossa, 163 
profunda artery, 561 
turbinated bones, 196 
articulations of, 196 
development of, 196 
ethmoidal process of, 196 
lachrymal process of, 196 
maxillary process of, 196 
vena cava, 633 
Inferior-posterior lobe of cere- 
bellum, 710 
Infracostal muscles, 420 
Inframaxillary nerves from fa- 
cial, 736 
Infraorbital artery, 524 
canal, 187 
foramen, 186 
groove, 187 
plexus of nerves, 724 
branches of facial, 735 
Infraspinatus muscle, 434 
Infraspinous fascia, 433 
Infratrochlear nerve, 722 
Infundibula of kidney, 945 
Infundibuliform fascia, 996 
Infundibulum of brain, 689 
of cochlea, 833 
of ethmoid, 183 
of heart, 909 
Ingrassias, processes of, 179 
Inguinal canal, 996 
glands, deep, 645 
superficial, 644, 1001 
hernia, 997 
dissection of, 991 
region, 860 
[Inion, 684] 
Inlet of pelvis, 268 
Innominate artery, 508 
peculiarities of, 508 
surgical anatomy of, 509 
bone, 260 
articulations of, 267 
attachment of muscles to, 
267 
development of, 266 
veins, 625 
peculiarities of, 626 
Inorganic constituents of bone, 
58 
Inspiration, muscles of, 421 
[Insula, 677] 
Interarticular fibro-cartilage, 52 
Interarticular fibro-cartilage- 
of scapulo-clavicular joint, 
325 
of jaw, 311 
of knee, 350 
of radio-ulnar joint, 333 
of sterno-clavicular joint, 
323 
ligament of ribs, 314 
Intercarotid ganglion, 790 
Intercellular substance of carti- 
lage, 51 
Interchondral ligaments, 317 
Interclavicular ligament, 323 
Intercolumnar fascia, 414, 993 
Intercondyloid notch, 274 
Intercostal arteries, 571 
anterior, 571 
superior, 552 
fasciae, 420 
lymphatics, 650 
lymphatic glands, 649 
muscles, 420 
nerves, 766 
spaces, 220 
veins, superior, 627 
Intercosto-humeral nerves, 758, 
766 
Interglobular spaces, 845 
Interlobular arteries of kidnev, 
950 
biliary plexus, 894 
Intermaxillary suture, 213 
Intermembranous ossification, 63 
Internal abdominal ring, 996 
annular ligament, 488 
capsule, 693 
carotid artery, 528 
cutaneous nerve, 756 
inguinal hernia, 997 
mammary artery, 551 
maxillary artery, 521 
branches of, 522 
mammary vein, 626 
oblique muscle, 414 
occipital crest, 163 
pterygoid plate, 179 
sphincter, 1011 
Internasal suture, 213 
Interossei muscles, dorsal of 
hand, 456 
of foot, 493 
palmar, 457 
plantar, 493 
Interosseous artery of forearm, 
567 
of foot, 606 
fibro-cartilages, 298 
membrane of forearm, 333 
of leg, 353 
nerve, anterior, 759 
posterior, 764 
veins of forearm, 624 
Interpeduncular space of brain, 
689 
Interspinales muscles, 410 
Interspinous ligaments, 304 
Intertransversales muscles, 410 
Intertransverse ligaments, 304 
Intertubular stroma of kidney, 
951 
Intervertebral notches, 143 
foramen, 160 
substance, 303 
Intestine, development of, 130 
Intestine- 
[growth of, 881J 
large, coats of, 886 
landmarks of, 1045 
lymphatics of, 649 
small, 874 
coats of, 876 
landmarks of, 1046 
Intracartilaginous ossification, 59 
Intralobular veins, 894 
Intraparietal fissure, 676 
[sulcus, 676, 686] 
[Intubation of the larynx, 931] 
Intumescentia gangliformis, 733 
Involuntary muscle, 67 
Iris, 810 
Irregular bones, 142 
Ischiatic lymphatic glands, 645 
Ischio-rectal fascia, 1022 
fossa, 1011 
position of vessels and nerves 
in, 1012 
region, surgical anatomy of, 
1011 
Ischium, 263 
body of, 263 
ramus of, 264 
spine of, 263 
tuberosity of, 264 
Island of Keil, 677 
Isthmus of the fauces, 851 
of thyroid gland, 940 
Iter ad infundibulum, 702 
a tertio ad quartum ventricu- 
lum, 701 
chordae posterius, 826 
Ivory of tooth, 844 
J. 
Jacob's membrane, 815 
Jacobson's nerve, 738, 831 
canal for, 174 
Jaw, lower, 197 
articulations of, 202 
attachment of muscles to, 202 
changes produced in, by age, 
200 
condyle of, 200 
development of, 200 
ligaments of, 311 
oblique line of, 199 
pterygoid fossa of, 200 
rami of, 199 
sigmoid notch of, 200 
symphysis of, 197 
upper. See Maxillary Bone. 
Jejunum, 876 
Joint. See Articulations. 
Jugular foramen, 207 
fossa, 175 
ganglion, 737 
process, 161 
surface, 174 
vein, anterior, 615 
external, 615 
internal, 616 
sinus or gulf of, 616 
posterior, external, 615 
K. 
Kerato-glossus muscle, 390 
Kerkring, valves of, 877 
Kidney, 944 1080 
INDEX. 
Kidney- 
calices of, 945 
cortical substance of, 946 
development of, 133 
ducts of, 952 
hilum of, 944 
infundibula of, 945 
landmarks of, 1045 
lymphatics of, 648, 951 
Malpighian bodies of, 946 
mammillae of, 946 
medullary substance, 946 
nerves of, 951 
papillae of, 946 
pelvis of, 945 
pyramids of Ferrein, 948 
renal artery, 949 
sinus of, 945 
[surgery of, 945] 
tubuli uriniferi, 946 
veins of, 634, 951 
weight and dimensions, 945 
[Knee, angle at, 242] 
Knee-joint, 346 
landmarks of, 1051 
Knuckles, landmarks of, 1062 
Krause's membrane, 65 
end-bulbs of, 75 
Kuhne, his views on the termi- 
nations of motor nerves, 
77 
Kiirschner, on structure of heart's 
valves, 910 
L. 
Labia cerebri, 691 
pudendi majora, 976 
minora, 976 
lymphatics of, 648 
Labial artery, 518 
glands, 839 
veins, superior, 614 
inferior, 614 
Labium tympanicum, 835 
vestibulare, 835 
Labyrinth, 832 
arteries of, 838 
fibro-serous membrane of, 837 
Lachrymal apparatus, 821 
artery, 531 
bone, 191 
articulations of, 192 
attachment of muscles to, 192 
development of, 192 
canals, 822 
caruncula, 821 
crest, 191 
fossa, 169 
gland, 821 
groove, 187 
nerve, 721 
papilla, 819, 822 
process of inferior turbinated 
bone, 196 
puncta, 822 
sac, 822 
tubercle, 189 
Lacteals, 638, 649, 878 
Lactiferous ducts, 989 
Lacuna magna, 960 
Lacunae of bone, 57 
Lacus lachrymalis, 819 
[Lambda, 684] 
Lambdoid suture, 203 
Lamella, horizontal, of ethmoid, 
181 
perpendicular, of ethmoid, 181 
of bone, articular, 296 
Lamellte of bone, 57 
Lamina cinerea, 687 
cribrosa, 174 
of sclerotic, 806 
fusca, 806 
spiralis ossea of cochlea, 834 
membranacea, 835, note 
suprachoroidea, 809 
of cornea, elastic, 806 
of the vertebrae, 143 
cerebellum, 711 
Laminae dorsales, 103 
Laminated tubercle of cerebel- 
lum, 710 
Lancisi, nerves of, 692 
Landmarks, medical and surgi- 
cal, 1025 
abdomen, 1041 
bony prominences of, 1043 
lines of, 1041 
manipulation of, 1044 
rings of, 1043 
viscera of, 1044 
ankle, 1053 
anterior tibial artery, 1054 
anterior fontanelle, 1026 
antrum, 1031 
anus, 1047 
aorta, division of, 1042 
arm, 1056 
cutaneous veins of, 1058 
axilla, 1057 
axillary artery, 1058 
back, 1037 
furrows of, 1037 
bladder, 1046 
brachial artery, 1058 
brain, levels of, 1027 
bursa, carpal, 1060 
digital, 1062 
of elbow, 1059 
of foot, 1053 
of patella, 1052 
buttocks, 1050 
carpus, 1060 
catheter, introduction of, 1048 
chest, 1034 
in the female, 1034 
clavicle, 1056 
below, 1035 
colotomy, 1046 
condyles of humerus, 1059 
coraco-acromial ligament, 1057 
cricoid cartilage, 1032 
crural arch, 1043 
cutaneous veins of arm, 1058 
diaphragm, 1044 
digital arteries, 1061 
furrows, 1061 
joints, 1062 
dorsal artery of foot, 1056 
ear, 1027* 
elbow, 1058 
cutaneous veins of, 1058 
epigastric artery, 1044 
eyelids, 1028 
eyes, 1028 
face, 1027 
facial artery, 1028 
features, 1031 
femoral artery, 1050 
Landmarks- 
femoral artery, compression of, 
1050 
ring, 1048 
fibula, 1053 
fingers, 1062 
foot, 1055 
arteries of, 1056 
bones of, 1055 
bursa of, 1056 
joints of, 1055 
foramina for fifth nerve, 1027 
forearm, 1059 
gall-bladder, 1045 
gluteal artery, 1051 
groin, 1049 
hand,1061 
head, 1026 
heart, 1035 
apex of, 1036 
auscultation of, 1036 
outlines of, 1035 
valves of, 1036 
Hunter's canal, 1050 
hyoid bone, 1032 
ilium, prominences of, 1043 
inguinal canal, 1044 
glands, 1049 
interdigital folds, 1061 
internal mammary artery, 
1035 
interosseous arteries of arm, 
1059 
of hand,1062 
intestines, large, 1045 
small, 1046 
kidney, 1045 
knee, 1051 
bony prominences of, 1051 
synovial membrane of, 1052 
knuckles, 1062 
lachrymal sac, 1029 
leg, 1053 
ligamentum patellae, 1052 
linea alba, 1042 
lineae semilunares, 1041 
lips, 1030 
liver, 1044 
lower jaw, 1028 
lung, 1036 
apex of, 1033 
outlines of, 1036 
malleoli, 1053 
mastoid process, 1026 
mediastinum, anterior, 1037 
metacarpal joints, 1061 
middle meningeal artery, 1027 
mouth, 1030 
nares, 1031 
nasal cavities and duct, 1029 
neck, 1031 
veins of, 1032 
Nelaton's line, 1049 
nose, 1029 
occipital protuberance, 1027 
olecranon, 1058 
[on the skull, 684] 
palm of hand, 1061 
palmar arches, 1061 
palpation by rectum, 1062 
pancreas, 1045 
parotid duct, 1028 
patella, 1051 
patellar bursa, 1052 
perineum, 1046 INDEX. 
1081 
Landmarks- 
perineum, bony framework of, 
1046 
raphe of, 1046 
peritoneum, 1042 
peroneal nerve, 1053 
phrenic nerve, 1053 
pit of the stomach, 1041 
plantar arteries, 1056 
fascia, 1056 
pleura, reflections of, 1037 
pomum Adami, 1032 
popliteal artery, 1054 
bursa, 1052 
tendons, 1052 
posterior tibial artery, 1055 
Poupart's ligament, 1043 
prostate gland, 1047 
pubes, bony prominences, 1043 
pudic artery, 1051 
pulley for superior oblique, 
1028 
pulse at wrist, 1060 
puncta lachrymalia, 1029 
pylorus, 1045 
radial artery, 1060 
radius, 1059 
raphe of perineum, 1046 
rectum, 1047 
palpation by, 1062 
ribs, rules for counting, 1034 
saphena veins, 1055 
saphenous opening, 1048 
sartorious, 1050 
scalp, 1026 
arteries of, 1026 
density of, 1026 
scapula, 1040 
sesamoid bones, 1062 
seventh nerve, 1028 
shoulder, 1057 
sinuses, cerebral, 1027 
frontal, 1026 
skull-cap, 1026 
thickness of, 1027 
spermatic cord, 1044 
spinal nerves, 1038 
spine, movements of, 1039 
of ilium, 1043 
of pubes, 1043 
spines of vertebras, 1038 
spleen, 1045 
sterno-clavicular joint, 1033 
sterno-mastoid muscle, 1033 
sternum, 1034 
stomach, 1045 
subclavian artery, 1033 
subcutaneous veins of hand, 
1062 
of neck, 1032 
supraclavicular fossa, 1033 
supracondyloid processes, 1058 
tabatiere anatomique, 1060 
teeth, 1030 
temporal artery, 1028 
tendo Achillis, 1054 
tendons of ankle, 1054 
of wrist, 1060 
thigh, 1048 
bend of, 1048 
throat, 1030 
thumb, 1061 
thyroid cartilage, 1032 
tibia, 1051 
tonsils, 1031 
Landmarks- 
trachea, 1032 
division of, 1037 
triangular ligament, 1047 
trigonum vesicae, 1047 
trochanters, 1049 
tuberosities of arm, 1057 
ulna, 1059 
ulnar artery, 1061 
umbilicus, 1041 
urethra, 1047 
in child, 1048 
vagina, examinations of, 1063 
vertebrae, spines of, 1037 
tabular plan of, 1039 
viscera, abdominal, 1044 
wrist, 1059 
zygoma, 1028 
Large intestine, 881 
areolar coat, 887 
caecum, 882 
colon, 883 
ilio-csecal valve, 882 
mucous coat, 887 
muscular coat, 887 
rectum, 886 
serous coat of, 887 
Laryngeal artery, inferior, 550 
superior, 515 
nerve, external, 740 
internal, 740 
recurrent, 740 
superior, 740 
from sympathetic, 789 
pouch, 924 
veins, 627 
Laryngo-tracheotomy, 930 
Laryngotomy, 930 
Larynx, 919 
actions of muscles of, 926 
arteries of, 927 
cartilages of, 919 
cavity of, 923 
glands of, 927 
glottis, 923 
interior of, 922 
[intubation of, 931] 
ligaments of, 922 
lymphatics of, 927 
mucous membrane of, 927 
muscles of, 924 
nerves of, 927 
rima glottidis, 923 
superior aperture of, 922 
veins of, 927 
ventricle of, 924 
vocal chords of, false, 923 
true, 924 
Lateral ginglymus, 300 
ligaments of liver, 890 
masses of ethmoid, 182 
region of skull, 211 
sinus of brain, 620 
tract of medulla oblongata, 
666, 669 
Lateralis nasi artery, 518 
Latissimus dorsi muscle, 401 
Lee, Dr., researches on sympa- 
thetic nerve, 797, note 
Leg, arteries of, 602, 603 
bones of, 276 
fascia of, 479 
deep transverse, 484 
ligaments of, 342 
lymphatics of, 645 
Leg- 
muscles of, 479 
back of, 481 
front of, 480 
nerves of, 782 
veins of, 630 
Lens, 817 
changes produced in, by age, 
818 
development of, 122 
suspensory ligament of, 818 
Lenticular ganglion, 723 
Lesser lachrymal bone, 191 
omentum, 867 
sciatic nerve, 779 
wings of sphenoid, 179 
Levator anguli oris, 375 
scapul<e, 403 
ani, 1017 
glandulse thyroidae, 940 
labii inferioris, 376 
superioris alaeque nasi, 374 
superioris, 375 
menti, 376 
palati, 394 
palpebrae, 371 
prostate, 1018 
Levatores costarum, 421 
Lieberkuhn, crypts of, 879 
Ligament, structure of, 296 
acromio-clavicular, superior, 
324 
inferior, 324 
alar of knee, 351 
of ankle, anterior, 354 
lateral, 355 
annular of radius, 333 
of wrist, anterior, 336 
posterior, 336 
of ankle, 354 
external, 356 
internal, 355 
of stapes, 831 
anterior, of knee, 347 
arcuate, 422 
aryteno-epiglottic, 922 
astragalo-scaphoid, 360 
atlo-axoid, anterior, 306 
posterior, 307 
of bladder, false, 957 
true, 957 
broad, of liver, 889 
calcaneo-astragaloid, external, 
358 
interosseous, 358 
posterior, 358 
calcaneo-cuboid, internal, 359 
long, 359 
short, 359 
superior, 359 
calcaneo-scaphoid, inferior, 
359 
superior, 359 
capsular. See Individual Joints. 
carpo-metacarpal, dorsal, 339 
interosseous, 339 
palmar, 339 
of carpus, 336 
central, of spinal cord, 654 
check, 310 
chondro-sternal, anterior, 315 
posterior, 315 
ciliary of eye, 812 
common vertebral, anterior, 
302 1082 
INDEX. 
Ligament- 
common vertebral, posterior, 
303 
conoid, 324 
coraco-acromial, 326 
coraco-clavicular, 324 
coraco-humeral, 327 
coracoid, 324 
coronary of liver, 890 
costo-clavicular, 322 
costo-transverse, 315 
costo-vertebral, or stellate, 313 
cotyloid, 345 
crico-arytenoid, 922 
crico-thyroid, 922 
crucial, of knee, 349 
cruciform, 308 
deltoid, 355 
dorsal. See Individual Joints. 
of elbow, 330 
anterior, 330 
external lateral, 330 
internal lateral, 330 
posterior, 330 
falciform of liver, 889 
femoral (Hey's), 1002 
gastro-phrenic, 870 
Gimbernat's, 413, 994, 1004 
glenoid, 327 
glosso-epiglottidean, 921 
of hip, 342 
hyo-epiglottic, 922 
ilio-femoral, 343 
ilio-lumbar, 318 
of incus, 830 
interarticular of ribs, 314 
interclavicular, 323 
interchondral, 317 
interosseous. See Individual 
Joints. 
interspinous, 304 
intertransverse, 304 
intervertebral, 303 
of jaw, 311 
of knee, 347 
of larynx, 921 
lateral See Individual Joints. 
longitudinal of liver, 889 
long plantar, 358 
lumbo-iliac, 318 
lumbo-sacral, 318 
of malleus, 830 
metacarpo-phalangeal, 340 
metacarpal, 340 
metatarsal, 361 
metatarso-phalangeal, 361 
mucosum of knee, 351 
nuchse, 401 
oblique, 333 
obturator, 475 
occipito-atloid, anterior, 309 
lateral, 309 
posterior, 309 
occipito-axoid, 309 
odontoid, 310 
orbicular, 333 
of ossicula, 830 
of ovary, 988 
palpebral or tarsal, 820 
of patella, 347 
of pelvis, 319 
of the phalanges, hand, 341 
foot, 361 
of the pinna, 823 
plantar, 359 
Ligament- 
posterior of knee, or posticum 
Winslowii, 347 
Poupart's, 412, 994, 1004 
pterygo-maxillary, 378 
pubic, anterior, 321 
posterior, 321 
superior, 321 
pubo-prostatic, 957 
radio-carpal, 336 
radio-ulnar joint, inferior, 333 
middle, 333 
superior, 333 
recto-uterine, 981 
rhomboid, 323 
round, of uterus, 988 
of liver, 889 
of radius and ulna, 332 
of hip, 342 
sacro-coccygeal, anterior, 321 
posterior, 321 
sacro-iliac, anterior, 319 
oblique, 320 
posterior, 319 
sacro-sciatic, greater, 320 
lesser, 320 
sacro-vertebral, 318 
of scapula, 326 
scapulo-clavicular, 324 
of shoulder, 326 
stellate, 313 
sterno-clavicular, anterior, 332 
posterior, 323 
of sternum, 314 
stylo-maxillary, 311 
subpubic, 321 
supraspinous, 304 
suspensory of incus, 830 
of lens, 818 
of liver, 889 
of malleus, 830 
of mamma, 427 
of penis, 964 
of spleen, 899 
sutural, 296 
tarsal of eyelids, 820 
tarso-metatarsal, 360 
of tarsus, 358 
teres of hip, 344 
thyro-arytenoid, inferior, 924 
superior, 924 
of thumb, 338 
tibio-tarsal, 354 
thyro-epiglottic, 922 
thyro-hyoid, 922 
tibio-fibula, 356 
transverse of atlas, 307 
of hip, 342 
of knee, 347 
of scapula, 326 
trapezoid, 324 
triangular of abdomen, 994 
of urethra, 1015 
of tympanic bones, 830 
of uterus, 981 
of vertebrae, 302 
vesico-uterine, 981 
of Winslow, 347 
of wrist, anterior, 336 
lateral external, 336 
lateral internal, 336 
posterior, 336 
of Zinn, 372 _ 
Ligamenta alaria, 351 
subflava, 304 
suspensoria of mamma, 427 
Ligamentum arcuatum exter- 
num, 423 
internum, 423 
denticulatum, 654 
latum pulmonis, 932 
mucosum, 351 
nuchae, 401 
patellae, 347 
pectinatum iridis, 811 
posticum Winslowii, 347 
spirale, 835 
teres, 344 
Ligature of arteries. See each 
Artery. 
Limbus laminae spiralis, 835 
luteus, 813 
[Line, Nelaton's, 272] 
landmarks of, 1049 
Linea alba, 418 
landmarks of, 1042 
aspera, 273 
ilio-pectinea, 264 
quadrati, 273 
splendens, 654 
Lineae semilunares, 419 
landmarks of, 1041 
transversae of abdomen, 419 
landmarks of, 1042 
transversae of fourth ventricle, 
713 
Lingual artery, 515 
surgical anatomy of, 516 
bone, 219 
ganglion, 790 
nerve, 729 
veins, 616 
Lingualis muscle, 390 
Linguetta laminosa, 703 
Lingula of sphenoid, 177 
Lips, 839 
arteries of, 517, 518 
Liquor Cotunnii, 837 
Scarpae, 838 
sanguinis, 38 
seminis, 974 
Lithotomy, parts concerned in 
operation of, 1020 
avoided in operation, 1021 
divided, 1021 
Littre, glands of, 960 
Liver, 889 
changes of position in, 889 
development of, 132 
distribution of vessels to, in 
foetus, 916 
ducts of, 896 
fibrous coat of, 892 
fissures of, 891 
[floating, 889] 
hepatic artery, 574, 894 
cells, 893 
duct, 896 
veins, 631, 894 
landmarks of, 1044 
ligaments of 889 
coronary, 890 
lateral, 890 
longitudinal, 889 
round, 891 
lobes of, 891 
lobules of, 892 
lymphatics of, 648 
nerves of, 795 
portal vein, 894 
situation, size, and weight, 889 INDEX. 
1083 
Liver- 
structure of, 892 
its surfaces and borders, 889 
vessels of, 894 
[wandering, 889] 
Lobe, central, 677 
cuneate, 680 
frontal, 676 
marginal, 679 
occipital, 677 
orbital, 676 
parietal, 676 
quadrate, 680 
temporo-sphenoidal, 677, 679 
uncinate, 680 
Lobes of cerebrum, 672 
of cerebellum, 708 
of kidney, 945 
of liver, 891 
of lung, 935 
of prostate, 963 
of testis, 970 
of thyroid, 939 
of thymus, 941 
Lobule of the ear, 823 
[paracentral, 680] 
[lingual, 678, 679] 
Lobules of liver, 893 
of kidney, 945 
of lung, 936 
Lobulettes of lung, 937 
Lobuli testes, 970 
Lobulus centralis of cerebellum, 
709 
Spigelii, 892 
Lobus caudatus, 892 
quadratus, 892 
Locus coeruleus, 713 
niger, 690 
perforatus anticus, 688 
posticus, 689 
Long bones, 141 
saphenous nerve, 774 
Longissimus dorsi muscle, 406 
Longitudinal fissure, of brain, 
672, 687 
of liver, 891 
ligament of liver, 889 
sinus of brain, superior, 619 
inferior, 620 
Longus colli muscle, 398 
Looped tubes of Henle, 947 
Lower extremity, arteries of, 593, 
594 
bones of, 259 
fascia of, 461 
lymphatics of, 644 
ligaments of, 341 
muscles of, 461 
nerves of, 770 
veins of, 630 
Lower, tubercle of, 908 
Lumbar arteries, 581 
fascia, 416 
ganglia, 792 
glands, 646 
nerves, 767 
plexus of nerves, 768 
region, 860 
vein, ascending, 633 
veins, 633 
vertebrae, 149 
development of, 152 
Lumbo-iliac ligament, 318 
Lumbo-sacral ligament, 318 
nerve, 768 
Lumbricales muscles, hand, 455 
foot, 491 
Lungs, 934 
air-cells of, 937 
air-sacs, 939 
apex of, landmarks of, 1033 
bronchial arteries, 939 
veins, 939 
capillaries of, 937 
development, 132 
in foetus, 916 
landmarks of, 1036 
lobes and fissures of, 935 
lobules of, 936 
lobulettes, 937 
lymphatics of, 650, 939 
nerves of, 939 
pulmonary artery, 937 
veins, 937 
root of, 936 
structure of, 936 
weight, color, etc., 936 
Lunulas of nails. 92 
Luschka's gland, 582 
Lymph, 39 
Lymphatic duct, right, 640 
Lymphatic glands, general anat- 
omy of, 87 
descriptive anatomy, anterior 
mediastinal, 650 
auricular posterior, 640 
axillary, 643 
brachial, 643 
bronchial, 650 
buccal, 641 
cervical, deep, 642 
superficial, 642 
in front of elbow, 643 
gluteal, 645 
of head, 640 
iliac, external, 646 
internal, 646 
inguinal, deep, 645 
superficial, 644 
intercostal, 649 
internal mammary, 650 
ischiatic, 645 
of large intestine, 649 
of lower extremity, 644 
lumbar, 646 
of neck, 642 
occipital, 640 
parotid, 640 
of pelvis, 646 
popliteal, 645 
radial, 643, 644 
sacral, 646 
of small intestines, 649 
of spleen, 649 
of stomach, 649 
submaxillary, 640 
of thorax, 650 
tibial anterior, 645 
ulnar, 643, 644 
of upper extremity, 643 
zygomatic, 640 
Lymphatics, general anatomv of, 
. 84 
origin of, 86 
plexus of, 86 
subdivision into deep and su- 
perficial, 638 
valves of, 85 
vessels, 84 
where found, 87 
Lymphatics- 
descriptive anatomy: 
abdomen, 646 
arm, 643 
bladder, 643 
bone, 55 
broad ligaments, 648 
cardiac, 650 
cerebral, 641 
cervical, superficial and deep, 
642 
chest, 650 
of clitoris, 648 
of cranium, 641 
diaphragm, 650 
face, superficial, 641 
deep, 641 
Fallopian tubes, 648 
gluteal region, 646 
head, superficial, 640 
heart, 650 
intercostal, 649 
internal mammary, 650 
intestines, 649 
kidneys, 648 
labia, 648 
lacteals, 649 
large intestine, 649 
leg, 644 
liver, 648 
lower extremity, 644 
lung, 650 
lymphatic duct, 640 
meningeal, 641 
mouth, 641 
neck, 642 
nose, 641 
nymphae, 648 
oesophagus, 651 
ovaries, 648 
pancreas, 649 
pelvis, 646 
penis, 647 
perineum, 647 
pharynx, 642 
pia mater, 641 
prostate, 648 
rectum, 648 
scrotum, 647 
small intestine, 649 
spleen, 649 
stomach, 649 
testicle, 648 
thoracic duct, 639 
thorax, 649 
thymic, 651 
thyroid, 651 
upper extremity, 643 
deep, 644 
superficial, 644 
uterus, 648 
vagina, 648 
Lymphoid connective tissue, 48 
of tongue, 801 
of tonsil, 857 
Lyra of fornix, 699 
M. 
Macula cribrosa, 832 
germinativa, 99 
lutea, 816 
Magnum of carpus, 254 
Majendie, foramen of, 653 
Malar bone, 192 
testicle, 648 1084 
INDEX. 
Malar bone- 
articulations of, 193 
attachment of muscles to, 
193 
development of, 193 
frontal process of, 192 
maxillary process of, 192 
orbital process of, 192 
zygomatic process of, 193 
canals, 193 
nerves, from facial, 735 
process of superior maxillary, 
189 
Male urethra, 959 
Malleolar arteries, external and 
internal, 605 
Malleolus, external, 282 
internal, 281 
Malleus, 829 
development of, 123 
suspensory ligament of, 830 
Malpighi, pyramids of, 946 
Malpighian bodies of kidney, 
946 
tufts, 946 
capsules, 946 
corpuscles of spleen, 902 
Mamma, areola of, 988 
lobules of, 989 
nerves of, 989 
nipple or mammilla of, 988 
vessels of, 989 
Mammae, development of, 123 
Mammary artery, internal, 551 
glands, 988 
lymphatic glands, 650 
veins, internal, 626 
Mammilla of breast, 988 
of kidney, 946 
Manubrium of sternum, 222 
of malleus, 829 
Marginal lobe, 679 
Marrow of bone, 54 
Marshall, vestigial fold of, 626 
Masseter muscle, 378 
Masseteric arteries, 524 
nerve, 727 
veins, 614 
[Mastication, muscles of, 365] 
Masto-occipital suture, 203 
Masto-parietal suture, 203 
[Mastoid cells, 172, 827] 
openings of, 827 
[disease, 172, 827] 
foramen, 171 
portion of temporal bone, 171 
process, 171 
vein,620 
Matrix of nail, 92 
Maxillary arch, foetal, 117 
artery, internal, 521 
bone, inferior, 197 
superior, 186 
development of, 190 
nerve, inferior, 727 
superior, 723 
process of inferior turbinated, 
196 
malar bone, 193 
sinus, 187 
tuberosity, 187 
vein, internal, 614 
Meatus auditorius externus, 173 
intern us, 174 
of nose, inferior, 218, 804 
Meatus- 
of nose, middle, 218, 804 
superior, 217, 804 
urinarius, male, 964 
female, 977 
Meatuses of the nose, 217, 804 
Meckel's cartilage, 118 
ganglion, 725 
Median artery of forearm, 568 
of spinal cord, 549 
nerve, 759 
vein, 624 
Mediastinal arteries, from inter- 
nal mammary, 552 
posterior, from aorta, 571 
lymphatic glands, 650 
Mediastinum, anterior, 934 
middle, 934 
landmarks of, 1037 
posterior, 934 
superior, 934 
testis, 970 
Medulla oblongata, 665 
anterior pyramids of, 666 
back of, 667 
fissures of, 666 
lateral tract, 666, 667 
olivary body, 666, 667 
posterior pyramids, 666 
restiform bodies, 666, 668 
septum of, 668 
structure of, 667 
spinalis, 654 
Medullary canal of bone, 62,141 
membrane of bone, 54 
plates, 103 
sheath of nerve-fibres, 70 
substance of brain, 72 
of kidney, 946 
of suprarenal capsules, 954 
velum, posterior, of cerebel- 
lum, 710 
Medullated nerve-fibres, 69 
Medullo-spinal veins, 629 
Meibomian glands, 820 
Membrana basilaris, 835 
fusca, 806 
of Graafian vesicle, 986 
limitans of retina, 813 
nictitans, 821 
pupillaris, 812 
sacciformis, 339 
tectoria, 835 
tympani, 829 
secundaria, 834 
Membrane of aqueous chamber, 
808 
arachnoid, spinal, 653 
cerebral, 663 
choroid, 809 
of Corti, 835 
costo-coracoid, 429 
crico-thyroid, 922 
of Descemet, 807 
fenestrated, 79 
hyaloid, 817 
Jacob's, 815 
limiting, 813 
pituitary, 803 
pupillary, 812 
of Reissner, 835 
Schneiderian, 803 
thyro-hyoid, 921 
Membranes of spinal cord, 652 
of brain, 661 
Membranous labyrinth, 837 
portion of urethra, 960 
semicircular canals, 837 
Meningeal artery, from ascend- 
ing pharyngeal, 520 
anterior, from internal caro- 
tid, 530 
lymphatics, 641 
middle, from internal maxil- 
lary, 523 
from occipital, 520 
posterior, from vertebral, 548 
small, from internal maxil- 
lary, 523 
veins, 616, 662 
Meninges. See Membranes. 
Menisci, 52 
[Menstrual organ, 983] 
Mental eminence, 213 
foramen, 198, 213 
process, 198 
Mesencephalon, 119 
Mesenteric artery, inferior, 579 
superior, 577 
glands, 649 
plexus of nerves, inferior, 796 
superior, 796 
vein, inferior, 634 
superior, 634 
Mesenteries, 867 
Mesoblast, 102 
Mesocsecum, 868 
Mesocephale, 669 
Mesocolon, ascending, 868 
descending, 868 
transverse, 869 
Mesonephros, 133 
Mesorchium, 135 
Mesorectum, 869 
Mesovarium, 135 
Metacarpal artery, 564 
articulations, 340 
Metacarpophalangeal articula- 
tions, 340 
Metacarpus, 255 
common characters oi, 255 
development of, 259 
peculiar bones of, 256 
Metanephros, 133 
Metatarsal articulations, 361 
artery, 606 
bones, 291 
Metatarso-phalangeal articula- 
tions, 391 
Metatarsus, 261 
development of, 294 
Metencephalon, 119 
Middle clinoid processes, 176 
ear, or tympanum, 826 
fossa of skull, 206 
meatus, 218, 804 
Mid-frontal process (foetal), 117 
Milk teeth, 843 
Mitral valve, 912 
Mixed bones, 142 
lateral column, 658 
[Model, use of the living, 33] 
Modiolus of cochlea, 833 
Molar glands, 840 
teeth, 841 
teeth, peculiar, 842 
Monro, foramen of, 699, 702 
Mons Veneris, 976 
Monticulus cerebelli, 709 
Morgagni, hydatid of, 127 INDEX. 
1085 
Morgagni- 
sinus of, 393 
Morsus diaboli, 984 
Motor oculi nerve, 718 
Mouth, 839 
landmarks of, 1030 
mucous membrane of, 839 
muscles of, 375 
Movement admitted in joints, 300 
Mucilaginous glands, 297 
Mucoid cellular tissue, 48 
Mucous glands of tongue, 800 
membrane, 96 
Muller, duct of, 133 
fibres of, 816 
Multicuspidati teeth, 841 
Multifidus spinae muscle, 409 
Muscle, general anatomy of, 64 
of animal life, 64 
arrangement of fibres of, 64 
bipenniforin, 362 
blood-vessels of, 67 
derivation of names, 363 
development of, 124 
fasciculi of, 64 
fibrils of, 65 
form of, 362 
involuntary, 67 
lymphatics of, 67 
meaning of the terms " origin " 
and " insertion," 363 
mode of connection of, with 
bone, cartilage, skin, etc., 
364 
nerves of, 67, 76 
of organic life, 76 
penniform, 362 
radiated, 362 
sarcous elements of, 65 
sheath of, 64 
size of, 362 
striped, 64 
structure of, 64 
tendons of, 364 
unstriped, 67 
voluntary, 64 
Muscles or muscle, descriptive 
anatomy: of abdomen, 412 
abductor minimi digiti (hand), 
455 
(foot), 490 
indicis, 456 
pollicis (hand), 452 
(foot), 489 
accelerator urinae, 1013 
accessorii orbicularis oris, 377 
.accessorius pedis, 491 
ad sacro-lumbalem, 406 
.adductor brevis, 471 
longus, 470 
magnus, 471 
pollicis (hand), 454 
(foot), 492 
anconeus, 447 
antitragicus, 854 
arytaeno-epiglottideus, inferior, 
926 
superior, 926 
arytaenoideus, 924 
attollens aurem, 369 
attrahens aurem, 369 
azygos uvulae, 395 
basio-glossus, 390 
•biceps (arm), 436 
.(thigh), 477 
Muscles or muscle- 
biventer cervicis, 408 
brachialis anticus, 437 
buccinator, 377 
[bulbo-cavernosus, 1014,1015] 
cervicalis ascendens, 406 
chondro-glossus, 391 
ciliary of eye, 812 
circumflexes palati, 394 
coccygeus, 1018 
cochlearis, 835 
complexus, 408 
compressor narium minor, 374 
nasi, 374 
sacculi laryngis, 926 
urethrae, 1017 
constrictor isthmi faucium, 396 
pharyngis inferior, 392 
medius, 393 
superior, 393 
urethrae, 1017 
[vaginae, 1015] 
coraco-brachialis, 436 
corrugator supercilii, 370 
cutis ani, 1011 
of cranial region, 366 
[cremaster, 975, 994] 
crico-arytaenoideus lateralis, 
925 
posticus, 924 
crico-thyroid, 924 
crureus, 468 
[deep transversus perinaei, 
1015] 
deltoid, 432 
depressor anguli oris, 376 
alae nasi, 374 
epiglottidis, 926 
labii inferioris, 376 
[urethrae, 1015] 
diaphragm, 422 
digastric, 388 
dilatator naris, anterior, 374 
posterior, 374 
[electrical points for, 496] 
erector clitoridis, 1015 
penis, 1014 
spinae, 406 
[of expression, 365] 
of external ear, 369 
external sphincter, 1011 
extensor brevis digitorum, 489 
carpi radialis brevior, 444 
longior, 444 
ulnaris, 446 
coccygis, 410 
digitorum communis, 446 
indicis, 448 
longus digitorum, 480 
minimi digiti, 446 
ossis metacarpi pollicis, 447 
primi internod ii pollicis, 447 
proprius pollicis, 480 
secundi internodii pollicis, 
448 
of face, 369 
[peculiarities of, 365] 
femoral region, anterior, 465 
internal, 470 
posterior, 477 
fibular region, 486 
flexor accessorius, 491 
brevis minimi digiti (hand), 
455 
(foot), 492 
Muscles or muscle- 
flexor brevis digitorum, 490 
pollicis (hand), 454 
(foot), 492 
carpi radialis, 440 
ulnaris, 441 
digitorum sublimis, 441 
longus digitorum, 485 
pollicis (hand), 442 
(foot), 484 
ossis metacarpi pollicis, 453 
profundus digitorum, 442 
gastrocnemius, 482 
gemellus superior, 476 
inferior, 47 6 
genio-hyo-glossus, 390 
genib-hyoid, 389 
gluteus maximuSj 473 
medius, 474 
minimus, 474 
gracilis, 470 
of hand, 452 
of head and face, 365 
helicis, major, 824 
minor, 824 
Hilton's, 926 
[Horner's, 371, 822] 
[how to ascertain action of, 
363] 
of hip, 472 
hyo-glossus, 390 
iliac region, 462 
iliacus, 464 
ilio-costalis, 406 
infracostal, 420 
infraspinatus, 434 
intercostal, 420 
internal sphincter, 1011 
interossei of foot, 493 
of hand, 455 
interspinales, 410 
intertransversales, 410 
[Jarjavay's, 1015] 
kerato-glossus, 390 
labial, 375 
of larynx, 924 
latissimus dorsi, 401 
of leg, 479 
levator anguli oris, 375 
ani, 1017 
glandulae thyroideae, 940 
labii inferioris, 376 
superioris, 374 
superioris alaeque nasi, 374 
menti, 376 
palati, 394 
palpebrae, 371 
prostatae, 1018 
scapulae, 403 
[uvulae, 395] 
levatores costarum, 421 
[ligamentous action of, 301] 
lingualis, 391 
longissimus dorsi, 406 
longus colli, 398 
lumbricales (hand), 455 
(foot), 491 
masseter, 378 
[of mastication, 365] 
multifidus spinae, 409 
musculus accessorius ad sacro- 
lumbalem, 406 
mylo hyoid, 389 
naso-labialis, 377 
of neck, 381 1086 
INDEX. 
Muscles or muscle- 
obliquus auris, 824 
abdominus externus, 412 
internus, 414 
capitis superior, 411 
inferior, 410 
obturator, externus, 476 
internus, 475 
occipito-frontalis, 366 
oculi, inferior, 373 
superior, 373 
omo-hyoid, 387 
opponens minimi digiti, 455 
pollicis, 453 
orbicularis oris, 377 
palpebrarum, 370 
of orbit, 371 
palate, 394 
palato-glossus, 396 
palato-pharyngeus, 396 
palmaris brevis, 454 
longus, 441 
pectineus, 470 
pectoralis, major, 427 
minor, 429 
of perineum, male, 1014 
female, 1015 
peroneus brevis, 486 
longus, 486 
tertius, 481 
of pharynx, 392 
plantaris, 483 
platysma myoides, 382 
popliteus, 484 
pronator quadratus, 443 
radii teres, 440 
psoas magnus, 463 
parvus, 464 
pterygoid, internal, 381 
external, 380 
pyramidalis abdominis, 418 
nasi, 374 
pyriformis, 475 
quadratus femoris, 476 
lumborum, 418 
menti, 376 
quadriceps extensor cruris, 467 
rectus abdominus, 417 
capitis anticus major, 397 
minor, 397 
externus, inferior, and in- 
ternus, 372 
femoris, 467 
lateralis, 398 
oculi, superior, 371 
posticus major, 410 
minor, 410 
retrahens aurem, 369 
rhomboideus major, 403 
minor, 403 
risorius, 378 
rotatores spinse, 409 
sacro-lumbalis, 406 
sartorius, 467 
landmarks of, 1050 
scalenus anticus, 398 
medius, 398 
posticus, 398 
semimembranosus, 478 
semispinalis dorsi, 409 
colli, 409 
semitendinosus, 478 
serratus magnus, 430 
posticus, superior, 404 
inferior, 404 
Muscles or muscle- 
sole of foot, 489 
first layer, 489 
second layer, 491 
third layer, 492 
fourth layer, 493 
soleus, 483 
sphincter, external, 1011 
internal, 1011 
vaginae, 1015 
spinalis dorsi, 408 
colli, 408 
splenius. 405 
capitis, 405 
colli, 405 
stapedius, 831 
sterno-cleido-mastoid, 385 
landmarks of, 1033 
sterno-hyoid, 386 
sterno-thyroid, 386 
[structure of, 363] 
stylo-glossus, 392 
stylo-hyoid, 388 
stylo-pharyngeus, 394 
subanconeus, 438 
subclavius, 429 
subcrureus, 469 
subscapularis, 433 
supinator brevis, 447 
longus, 444 
supraspinales, 410 
supraspinatus, 433 
temporal, 379 
tensor-palati, 394 
tarsi, 371 
tympani, 830 
vaginae femoris, 466 
teres major, 435 
minor, 434 
thyro-arytaenoideus, 925 
thyro-epiglottideus, 926 
thyro-hyoid, 387 
tibialis anticus, 479 
posticus, 485 
of tongue, 389 
trachelo-mastoid, 408 
tragicus, 824 
transversalis abdominis, 415 
colli, 406 
transversus auriculae, 824 
pedis, 492 
perinaei, 1014 
(female), 1015 
trapezius, 400 
triangularis sterni, 420 
triceps, extensor cubiti, 438 
extensor cruris, 468 
femoralis, 469 
of tympanum, 830 
of ureters, 957 
of urethra, 1014 
vastus externus, 468 
interims and crureus, 468 
zygomaticus major, 375 
minor, 375 
Muscular fibres of heart, 66 
[Muscularis mucosae, 67, 877] 
Musculi papillares, left ventri- 
cle, 912 
right, 910 
pectinati in left auricle, 911 
in right, 909 
Musculo-cutaneous nerve of arm 
756 
from peroneal, 783 
Musculo-spiral nerve, 762 
Musculo-phrenic artery, 552 
Musculus accessorius ad sacro- 
lumbalein, 406 
suspensorius duodeni, 876, note 
Mylo-hyoid artery, 523 
groove, 199 
muscle, 389 
nerve, 729 
ridge, 199 
Myrtiform fossa, 186 
N. 
Nails, 92 
Nares, anterior, 215 
posterior, 856 
landmarks of, 1031 
septum of, 217, 803 
Nasal angle, 185 
artery, of internal maxillary, 
524 
of ophthalmic, 531 
of septum, 518 
bones, 185 
articulations of, 186 
development of, 185 
cartilages, 802 
crest, 185 
duct, 822 
eminence, 168, 213 
fossae, 215, 803 
arteries of, 804 
landmarks of, 1029 
mucous membrane of, 804 
nerves of, 805 
veins of, 805 
groove, 185 
nerve, 721 
nerves from Meckel's ganglion, 
726 
notch, 168 
process, 189 
spine, 168 
anterior, 190 
posterior, 193 
venous arch, 613 
[Nasion, 684] 
Nasmyth's membrane, 847 
Naso-maxillary suture, 213 
Naso-palatine nerve, 726 
Nates of brain, 702 
[Necessity, triangle of, 525] 
Neck, glands of, 642 
landmarks of, 1031 
lymphatics of, 642 
muscles of, 381 
triangle of, anterior, 525 
posterior, 527 
veins of, 615 
landmarks of, 1032 
[Nelaton's line, 272] 
landmarks of, 1049 
Nerve-corpuscles, 69 
Nerves, general anatomy of, 72 
cerebro-spinal, 73 
funiculi of, 73 
neurilemma of, 73 
origin of, 74 
plexus of, 73 
sheath of, 73 
spinal roots of, 744 
subdivision of, 72 
termination of, 74 
vessels of, 73 INDEX. 
1087 
Nerves- 
of special sense, 716 
Nerves or nerve, descriptive 
anatomy of: abducens, 
731 
accessory obturator, 773 
acromiales, 751 
anterior crural, 773 
auditory, 736 
auricular, posterior, 735 
of vagus, 740 
auricularis magnus, 750 
of auriculo-temporal, 728 
of second cervical, 747 
of small occipital, 750 
of brachial plexus, 752 
buccal, 728 
of facial, 736 
cardiac. 790 
inferior, 791 
middle, 790 
superior, 790 
plexus, deep, 792 
superficial, 793 
of pneumogastric, 739 , 
cavernous, of penis, 797 
cervical anterior, 749 
posterior, 747 
superficial, 750 
cervico-facial, 736 
chorda tympani, 734, 831 
ciliary, long, 722 
short, 722 
circumflex, 756 
claviculares, 751 
coccygeal, 776 
cochlear, 838 
communicans noni, 752 
peronei, 782 
of Cotunnius, 726 
cranial, 715 
crural anterior, 773 
cutaneous. See that heading, 
deep palmar, 762 
temporal, 728 
dental anterior, 725 
inferior, 729 
posterior, 724 
descendens noni, 743 
digastric, from facial, 735 
digital (foot), 782, 783 
dorsal (hand), 764 
peculiar, 767 
of penis, 778 
spinal, 764 
dorsi-lumbar, 767 
of dura mater, 662 
eighth pair, 736 
eleventh pair, 741 
of eyeball, 717 
facial, 732 
fifth, 719 
fourth, 719 
frontal, 721 
ganglionic branch of nasal, 
722 
gastric branches of vagus, 795 
genito-crural, 770 
glosso-pharyngeal, 736 
gluteal, inferior, 780 
superior, 778 
great petrosal, 727 
great splanchnic, 791 
gustatory, 729 
hemorrhoidal, inferior, 796 
Nerves or nerve- 
of heart. See Cardiac. 
hepatic, 794 
hypoglossal, 742 
ilio-hypogastric, 769 
ilio-inguinal, 770 
incisor, 729 
inferior maxillary, 727 
inframaxillary, of facial, 736 
infraorbital of facial, 735 
infra trochlear, 722 
intercostal, 766 
intercosto-humeral, 766 
interosseous, anterior, 759 
posterior, 764 
ischiadic, great, 780 
small, 779 
Jacobson's, 738 
labial, 725 
of labyrinth, 838 
lachrymal, 721 
of Lancisi, 692 
large cavernous, 797 
laryngeal, external, 740 
internal, 740 
recurrent, 740 
superior, 740 
lesser splanchnic, 791 
lingual of fifth, 729 
of glosso-pharyngeal, 738 
long ciliary, 722 
saphenous, 774 
thoracic, 754 
lumbar, 767 
lumbo-sacral, 768 
malar branch of orbital nerve, 
723 
of facial, 735 
masseteric, 727 
maxillary, inferior, 727 
superior, 723 
median, 759 
mental, 729 
middle cardiac, 790 
motor' of the eye, common, 
718 
external, 730 
musculo-cutaneous of arm, 756 
leg, 783 
musculo-spiral, 762 
mylo-hyoid, 729 
nasal, ophthalmic, 721 
from Meckel's ganglion, 727 
from Vidian, 727 
naso-palatine, 726 
ninth, 736 
obturator, 770 
occipital, great, 747 
small, 750 
of facial, 735 
of third cervical, 747 
oesophageal, 741 
olfactory, 716 
ophthalmic, 720 
optic, 717 
orbital nerves, their relation, 
731 
in cavernous sinus, 732 
in orbit, 732 
in sphenoidal fissure, 732 
orbital of superior maxillary, 
723 
palatine, anterior or large, 7 25 
external, 726 
posterior or small, 726 
Nerves or nerve- 
palmar, cutaneous, of median, 
759 
ulnar, 761 
palpebral, 725 
par vagum, 738 
pathetic, 719 
perforans Casserii, 756 
perineal, 778 
superficial, 780 
peroneal, 782 
landmarks of, 1053 
petrosal, superficial, external 
or large, 727, 733 
small, 733 
pharyngeal, of pneumogastric, 
740 
of glosso-pharyngeal, 738 
of sympathetic, 790 
of Meckel's ganglion, 727 
of external laryngeal, 740 
phrenic, 752 
plantar, cutaneous, 781 
external, 782 
internal, 781 
pneumogastric, 738 
popliteal, external, 782 
internal, 780 
portia inter duram et mollem, 
733 
portio dura, 732 
mollis, 736 
posterior auricular, 735 
pterygoid, 728 
pterygo-palatine, 727 
pudendal, inferior, 780 
pudic, 778 
pulmonary, from vagus, 741 
radial, 763 
recurrent laryngeal, 740 
recurrent to tentorium, 719 
renal splanchnic, 719 
respiratory, external, 754 
internal, 752 
sacral, 775 
plexus. 777 
saphenous, long or 
774 
short or external, 781 
sciatic, great, 780 
small, 779 
short ciliary, 723 
sixth, 731 
small cavernous, 797 
spheno-palatine, 726 
spinal, 744 
accessory, 741 
splanchnic, great, 791 
small, 791 
smallest, 791 
sternales, 751 
stylo-hyoid of facial, 735 
subclavian, 754 
suboccipital, 747 
posterior branch of, 748 
subscapular, 755 
superficialis colli, 750 
superior cardiac, 790 
maxillary, 723 
supraclavicular, 751 
supramaxillary of facial, 736 
supraorbital, 721 
suprascapular, 755 
supratrochlear, 721 
sympathetic, 784 1088 
INDEX. 
Nerves or nerve- 
temporal, deep, 728 
of facial, 735 
of auriculo-temporal, 728 
temporo-facial, 735 
temporo-malar, 723 
tenth, 738 
third, or motor oculi, 718 
[thirteenth cranial, 735] 
thoracic posterior, 754 
anterior, 755 
thyro-hyoid, 743 
tibial, anterior, 782 
posterior, 781 
of tongue, 801 
tonsillar, 738 
trifacial or trigeminus, 719 
trochlear, 719 
twelfth, 742 
tympanic, of glosso-pharyn- 
geal, 737, 831 
of facial, 734 
ulnar, 761 
uterine, 797 
vaginal, 797 
vagus, 738 
vestibular, 838 
Vidian, 727 
of Wrisberg, 757 
Nervous substance, chemical 
analysis, 71 
gelatinous, 68 
gray, 68 
white, 69 
layer of retina, 814 
Nervous system, general anatomy 
of, 68 
fibrous nervous matter, 69 
ganglia, 77 
gelatinous fibres, 68 
gray or cineritious substance, 
68 
sympathetic, 71 
composition of, 71 
vesicular nervous matter, 68 
white or medullary substance, 
69 
Nervus cardiacus magnus, 790 
minor, 791 
superficial cordis, 790 
Neurilemma, 73 
of cord, 654 
Neural crest, 120 
Neuroglia, 72 
of cord, 656 
Nidus hirundinis, of cerebellum, 
710 
Ninth nerve, 936 
Nipple, 988 
landmarks of, 1034 
Nodes of Ranvier, 70 
Nodule of cerebellum, 710 
Noduli Arantii, 910, 912 
Non-medullated nerve-fibres, 71 
Nose, 801 
arteries of, 803 
bones of, 185 
cartilages of, 802 
cartilage of septum of, 803 
development of, 123 
fossae of, 215, 803 
landmarks of, 1029 
mucous membrane of, 803 
muscles of, 374 
nerves of, 803 
Nose- 
veins of, 803 
Nostrils, landmarks of, 1029 
Notch, cotyloid, 265 
ethmoidal, 169, 181 
intercondyloid, 274 
nasal, 168 
pterygoid, 179 
sacro-sciatic, greater, 263 
lesser, 263 
sigmoid, 200 
spheno-palatine, 195 
supraorbital, 167 
suprascapular, 235 
Notochord, 106, 114 
Nucleus amygdalae, 694 
caudatus, 693 
lenticularis, 693 
Nuck, canal of, 975, 988 
Nutrient artery of bone, 55 
Nymphae, 976 
lymphatics of, 648 
O. 
[Obelion, 685] 
Oblique inguinal hernia, 998 
coverings of, 998 
ligament, 333 
line of the clavicle, 230 
of lower jaw, 199 
of radius, 248 
Obliquus auris muscle, 824 
externus abdominis, 412 
internus, 414 
inferior capitis, 410 
superior, 411 
inferior oculi, 373 
superior, 372 
Obturator artery, 587 
peculiarities of, 587 
relation of, to femoral ring, 
1007 
externus muscle, 476 
internus, 475 
fascia, 1022 
foramen, 266 
ligament or membrane, 475 
nerve, 770 
accessory, 773 
veins, 632 
Occipital artery, 519 
bone, 160 
articulations of, 164 
attachment of muscles to, 164 
development of, 164 
crests, 160, 163 
protuberances, 160, 163 
fossae, 162 
lobe, 677 
lymphatic glands, 640 
groove, 172 
sinus, 620 
triangle, 527 
vein, 615 
Occipitalis major nerve, 747 
minor, 750 
Occipito-atloid articulation, 309 
Occipito-axoid articulation, 309 
Occipito-frontalis muscle, 366 
Occiput, arteries of, 519 
Ocular cleft, 121 
cup, 121 
vesicle, primitive, 121 
secondary, 121 
Odontoblasts, 848 
Odontoid ligaments, 310 
tubercle for, 161 
process of axis, 146 
(Esophageal arteries, 571 
branches of vagus nerve, 741 
glands, 856 
opening of, diaphragm, 424 
plexus, 741 
(Esophagus, 857 
lymphatics of, 651 
structure of, 857 
surgical anatomy of, 857 
Olecranon process, 243 
fracture of, 459 
landmarks of, 1058 
Olfactory bulb, 716 
cells, 804 
foramina, 181 
fossae (foetal), 123 
nerve, 716 
Olivary bodies of medulla ob- 
longata, 666, 667 
fasciculus, 667 
process, 176 
Omenta, 867 
Omentum, gastro-colic, 867 
gastro-hepatic, 867 
gastro-splenic, 867 
great, 867 
lesser, 867 
Omo-hyoid muscle, 387 
Omphalo-mesenteric arteries, 
foetal, 125 
duct, 108 
veins, 125 
Opening of aorta in left ventricle, 
912 
aortic, in diaphragm, 424 
caval, in diaphragm, 424 
of coronary sinus, 908 
of inferior cava, 908 
left auriculo-ventricular, 911 
oesophageal in diaphragm, 484 
of pulmonary artery, 909 
veins, 911 
right auriculo-ventricular, 909 
saphenous, 466, 1003 
landmarks of, 1048 
of superior cava, 908 
Operation for club-foot, 487 
of laryngotomy, 930 
of laryngo-tracheotomy, 930 
of lithotomy, 1020 
of oesophagotomy, 858 
of staphylorraphy, 396 
for strabismus, 374 
tracheotomy, 930 
for wry-neck, 386 
ligature of arteries. See Sur- 
gical Anatomy of each. 
Operculum, 676 
[Ophryon, 684] 
Ophthalmic artery, 530 
ganglion, 722 
nerve, 720 
vein, 621 
Opponens minimi digiti muscle, 
455 
pollicis muscle, 453 
Optic commissure, 717 
foramen, 176, 206 
groove, 176 
lobes, 703 
nerve, 717 
inter-retinal fibres, 717 INDEX. 
1089 
Optic thalami, 699 
tract, 717 
Ora serrata, 813 
Orbicular bone, 830 
ligament, 333 
Orbicularis ciliaris, 371 
latus, 371 
oris muscle, 377 
palpebrarum, 370 
Orbit, 214 
arteries of, 531 
muscles of, 371 
relation of nerves in, 732 
Orbital artery, 524 
foramina, 179 
lobe, 676 
nerve, 723 
process of malar, 192 
of palate, 195 
Organic constituent of bone, 59 
Orifice, oesophageal of stomach, 
869 
pyloric of stomach, 871 
Os calcis; 284 
development of, 294 
hyoides, 219 
innominatum, 260 
development of, 266 
magnum of carpus, 254 
orbiculare, 830 
planum, 182 
unguis, 191 
Os uteri, 981 
Ossa triquetra, 184 
Ossicula auditus, 829 
ligaments of, 830 
Ossification, period of, 63 
intracartilaginous, 59 
intramembranous, 63 
of bone, 59 
of spine, progress in, 152 
Osteoblasts, 60 
Osteoclasts, 62 
Osteo-dentine, 846 
Osteology, 141 
Ostium abdominale of Fallopian 
tube, 991 
internum or uterinum, 984 
uteri internum, 981 
Otic ganglion, 729 
Otoliths, 838 
Outlet of pelvis, 269 
Ovarian arteries, 581 
plexus of nerves, 794 
veins, 634 
Ovary, 984 
corpus luteum of, 987 
development of, 135 
Graafian vesicles of, 986 
ligament of, 988 
lymphatics of, 648 
nerves of, 989 
ovicapsule of, 986 
shape, position, and dimen- 
sions, 985 
stroma of, 984 
tunica albuginea of, 986 
vessels of, 989 
Ovicapsule of Graafian vesicle, 
986 
Oviducts, 984 
Ovisacs of ovary, 986 
Ovula of Naboth, 983 
Ovum, 99 
discharge of, 987 
Ovum- 
discus proliger us of, 99 
fecundation of, 101 
germinal spot of, 100 
vesicle of, 100 
vitelline membrane of, 99 
yolk of, 100 
zona pellucida of, 99 
P. 
Pacchionian depressions, 165 
glands, 619, 662 
Pacinian corpuscles, 75 
Pad of corpus callosum, 692 
Palatal glands, 850 
Palate, arches of, 851 
development of, 117 
bone, 193 
articulations of, 196 
attachment of muscles to, 
196 
development of, 195 
horizontal plate of, 193 
orbital process of, 195 
process of superior maxil- 
lary, 187 
sphenoidal process of, 195 
turbinated crest of, 194 
vertical plate of, 194 
hard, 850 
muscles of, 394 
soft, 850 
Palatine artery, ascending, 517 
descending or posterior, 524 
canal, anterior, 189 
accessory, 193 
posterior, 193 
fossa, anterior, 189 
nerves, 726 
process of superior maxillary, 
189 
veins, inferior, 614 
Palato-glossus muscle, 392, 396 
Palato-pharyngeus, 396 
[Palm, lines in, 340] 
Palmar arch, deep, 562 
superficial, 566 
cutaneous nerve, 759 
fascia, 450 
interossei arteries, 565 
nerve, deep, of ulnar, 762 
superficial, 762 
veins, 623 
Palmaris brevis muscle, 454 
longus muscle, 441 
Palm of hand, landmarks of, 
1061 
Palpebrae, 819 
Palpebral arteries, 532 
cartilages, 819 
fissures, 819 
folds of conjunctiva, 821 
ligaments, 820 
muscles, 370 
veins, inferior, 614 
superior, 614 
Pampiniform plexus of veins, 
633, 968, 988 
Pancreas, 897 
development of, 132 
landmarks of, 1045 
lymphatics of, 649 
structure of, 898 
[surgery of, 899] 
Pancreas- 
vessels and nerves of, 899 
Pancreatic arteries, 577 
duct, 898 
plexus of nerves, 794 
veins, 635 
Pancreatica magna artery, 577 
Pancreatico-duodenal artery, 577 
inferior, 577 
plexus of nerves, 794 
vein, 635 
Papilla lachrymalis, 819, 822 
spiralis, 836 
Papillae of tooth, 846 
conicae vel filiformes, 800 
conjunctival, 822 
fungiformes (mediae), 799 
of kidney, 946 
maximae (circumvallatae), 799 
of skin, 91 
of tongue, 799 
Papillary layer of skin, 91 
[Paracentral lobule, 680] 
Par vagum, 738 
Parallel fissure, 677 
Parietal bones, 164 
articulations of, 166 
attachment of muscles to, 
166 
development of, 166 
eminence, 164 
foramen, 164 
lobe. 676 
Parieto-occipital fissure, [676], 
678, [687] 
Parotid duct, 853 
landmarks of, 1028 
gland, 852 
accessory portion of, 853 
nerves of, 853 
vessels of, 853 
lymphatic glands, 640 
veins, 614 
Parovarium, 136, 988 
Patella, 277 
articulations of, 278 
attachment of muscles to, 278 
development of, 278 
fracture of, 495 
landmarks of, 1052 
Pecquet, reservoir of, 639 
Pectineus muscle, 470 
Pectiniforme septum, 965 
Pectoral region, dissection of, 427 
Pectoralis major, 427 
minor, 429 
Peculiar dorsal vertebrae, 149 
Pedicles of a vertebra, 143 
Peduncles of cerebellum, 711 
of cerebrum, 690, 706 
of corpus callosum, 692 
of pineal gland, 702 
Pelvic fascia, 1021 
parietal or obturator layer, 
1022 
visceral layer, 1022 
plexus, 796 
Pelvis, 267, 955 
arteries of, 584 
articulations of, 319 
axes of, 269 
boundaries of, 268 
brim of, 268 
cavity of, 268 
diameters of, 269 1090 
INDEX. 
Pelvis- 
false, 268 
inlet of, 268 
ligaments of, 319 
lymphatics of, 646 
male and female, differences 
of, 270 
outlet of, 269 
position of, 269 
position of viscera at outlet of, 
1019 
true, 268 
Pelvis of kidney, 945 
[to show rocking of, 352] 
Penis, 964 
arteries of, 965 
body of, 964 
corpora cavernosa, 964 
corpus spongiosum, 966 
development of, 138 
dorsal artery of, 589 
nerve of, 778 
vein of, 632 
lymphatics of, 647. 966 
muscles of, 1014 
nerves of, 966 
prepuce of, 964 
root of, 964 
suspensory ligament, 964 
Penniform muscle, 362 
Perforans Casserii nerve, 756 
Perforated space, anterior, 688 
posterior, 689 
Perforating arteries, of hand, 565 
from mammary artery, 552 
plantar, 610 
profunda, 599 
Pericardiac arteries, 552, 570 
Pericardium, relations of, 904 
fibrous layer of, 905 
serous layer of, 905 
structure of, 905 
[surgery of, 906] 
vessels of, 906 
vestigial fold of, 626 
Perilymph, 837 
Perineal artery, superficial, 589 
transverse, 589 
fascia, deep, 1015 
superficial, 1013 
nerve, 778 
superficial, 778 
Perineum, 1012 
abnormal course of arteries in, 
1021 
deep boundaries of, 1012 
development of, 138 
landmarks of, 1046 
lymphatics of, 647 
muscles of, 1014 
surgical anatomy of, 1013 
Perineurium, 73 
Periosteum, 54 
of teeth, 841 
[Peritoneum of foetus, 863] 
greater cavity of, 862 
landmarks of, 1042 
lesser cavity of, 861, 865 
ligaments of, 867 
mesenteries of, 867 
omenta of, 867 
reflections traced, 863 
Permanent cartilage, 50 
teeth, 841 
Peroneal artery, 608 
Peroneal artery- 
anterior, 609 
peculiarities of, 609 
nerve, 782 
veins, 631 
Peroneus brevis muscle, 486 
longus, 486 
tertius, 481 
Perpendicular plate of ethmoid, 
181 
Pes accessorius, 696 
hippocampi, 696 
Petit, canal of, 818 
Petro-occipital suture, 203 
Petro-sphenoidal suture, 203 
Petrosal nerve, superficial or 
large, from Vidian, 727 
external, 733 
small, 733 
sinus inferior, 622 
superior, 622 
Petrous ganglion, 737 
portion of temporal bone, 173 
Peyer's glands, 880 
Phalanges, hand, 257 
articulations of, 258, 341 
development of, 259 
foot, 292 
articulations of, 293, 361 
development of, 294 
[Phalangette, 258] 
[Phalangine, 258] 
[Phalanx, 258] 
Pharyngeal aponeurosis, 856 
arches, 116 
artery, ascending, 520 
clefts, 116 
ganglion, 790 
glands, 856 
nerve, from external laryngeal, 
740 
from glosso-pharyngeal, 738 
from Meckel's ganglion, 727 
from sympathetic, 789 
from vagus, 740 
plexus of nerves, 740, 789 
spine, 162 
tonsil, 857 
vein, 616 
Pharynx, 856 
aponeurosis of, 856 
arteries of, 520 
development of, 130 
mucous membrane of, 856 
muscles of, 393 
Phleboliths, 632 
Phrenic arteries, 581 
nerve, 752 
plexus of nerves, 794 
veins, 634 
Pia mater, of brain, 664 
of cord, 654 
testis, 970 
Pigment, 50 
of iris, 811 
of skin, 90 
Pigmentary layer of retina, 815 
Pillars of external abdominal 
ring, 414, 993 
of diaphragm, 424 
of fauces, 851 
of fornix, 699 
Pineal gland, 702 
penduncles of, 702 
Pinna of ear, 823 
Pinna of ear- 
ligaments of, 823 
muscles of, 824 
nerves of, 824 
vessels of, 824 
Pisiform bone, 252 
Pit of stomach, landmarks of, 
1041 
Pituitary body, 689 
development of, 119 
fossa, 176 
membrane, 803 
Placenta, 113 
Placental sinus, 113 
circulation, 126 
Plantar artery, external, 610 
internal, 610 
cutaneous nerve, 781 
fascia, 488 
ligaments, 359 
nerve, external, 782 
internal, 781 
veins, external, 631 
internal, 631 
Plantaris muscle, 483 
Plasma, 38 
Platysma myoides, 382 
Pleura, 931 
cavity of, 931 
costalis, 931 
pulmonalis, 931 
reflections of, traced, 931 
vessels and nerves of, 932 
Plexus of nerves, 73 
aortic, 796 
brachial, 752 
cardiac, deep, 792 
superficial, 793 
carotid, 789 
external, 789 
cavernous, 789 
cervical, 749 
posterior, 747 
coeliac, 794 
colic, left, 796 
middle, 796 
right, 796 
coronary, anterior, 793 
posterior, 793 
cystic, 794 
diaphragmatic, 794 
epigastric or solar, 793 
facial, 790 
gastric, 794 
gastro-duodenal, 794 
gastro-epiploic, 794 
left, 794 
great cardiac, 792 
hemorrhoidal superior, 796 
inferior, 796 
hepatic, 795 
hypogastric, 796 
inferior, 796 
ileo-colic, 796 
infraorbital, 725 
lumbar, 768 
meningeal, 790 
mesenteric, inferior, 796 
superior, 796 
oesophageal, 741 
ophthalmic, 789 
ovarian, 794 
pancreatic, 794 
pancreatico-duodenal, 794 
patelke, 774 INDEX. 
1091 
Plexus- 
pharyngea., 740, 790 
phrenic, 794 
prostatic, 796 
pulmonary, anterior, 741 
posterior, 741 
pyloric, 794 
renal, 794 
sacral, 777 
sigmoid, 796 
solar, 793 
spermatic, 794 
splenic, 794 
superficial cardiac, 793 
suprarenal, 794 
tonsillar, 738 
tympanic, 737 
vaginal, 797 
vertebral, 791 
vesical, 796 
Plexus of veins. See Veins. 
Plica semilunaris, 821 
Pneumogastric lobule of cerebel- 
lum, 710 
nerve, 738 
Polar globules of Kobin, 100 
Pomum Adami, 919 
landmarks of, 1032 
Pons hepatis, 891 
Tarini, 689 
Varolii, 669 
Popliteal artery, 599 
branches of, 602 
lymphatic glands, 645 
nerve, external, 782 
internal, 780 
peculiarities of, 601 
space, 600 
surgical anatomy of, 601 
vein, 631 
Popliteus muscle, 484 
Pores of the skin, 94 
Portal canals, 892 
fissure, 891 
vein, 636, 892, 894 
Portio dura of seventh nerve, 
732 
inter duram et mollem, 733 
mollis, 736 
Porus opticus of sclerotic, 806 
Posterior. See under each sepa- 
rate head. 
Posterior glenoid process, 171 
vesicular column, 660 
Post-oral arches (foetal), 117 
Pott's fracture, 495 
Pouch of Douglas, 981 
Pouches, laryngeal, 924 
Poupart's ligament, 412, 993, 
1003 
landmarks of, 1043 
Pneputium clitoridis, 976 
Praevertebral fascia, 385 
Precentral fissure, 676 
[sulcus, 676, 686] 
Precuneus, 680 
Prepuce, 964 
Primitive trace, 102 
otic vesicle, 122 
sheath of nerve-fibre, 70 
Princeps cervicis artery, 519 
pollicis artery, 564 
Processes or process, acromion, 
235 
alveolar, 189 
angular, external, 168 
Processes or process- 
angular, internal, 168 
auditory, 173 
basilar, 162 
ciliary, 810 
clinoid, anterior, 179 
middle, 176 
posterior, 177 
cochleariform, 175, 828 
condyloid of lower jaw, 200 
coracoid, 236 
coronoid of lower jaw, 200 
of ulna, 243 
ethmoidal of inferior turbinat- 
ed, 196 
frontal of malar, 192 
hamular of lachrymal, 191 
of sphenoid, 179 
of helix, 823 
of Ingrassias, 179 
jugular, 161 
lachrymal of inferior turbi- 
nated bone, 196 
malar, 189 
of malar bone, 193 
mastoid, 171 
landmarks of, 1027 
maxillary of inferior turbi- 
nated, 196 
mental, 198 
nasal, 189 
odontoid of axis, 146 
olecranon, 243 
olivary, 176 
orbital of malar, 192 
of palate, 195 
palatine of superior maxillary, 
189 
post-glenoid, 171 
pterygoid of palate bone, 194 
of sphenoid, 180 
sphenoidal of palate, 195 
spinous of tibia, 174 
of ilium, 263 
of sphenoid, 178 
styloid of temporal, 174 
of ulna, 247 
of radius, 249 
unciform, 255 
of ethmoid, 182 
vaginal of sphenoid, 178 
of temporal, 174 
vermiform of cerebellum, 710 
zygomatic, 193 
Processus ad medullam, 711 
ad pontem, 711 
brevis of maileus, 829 
clavatus, 667 
cochleariformis, 175, 828 
e cerebello ad testes, 711 
gracilis of malleus, 829 
Profunda cervicis artery, 552 
femoris artery, 588 
inferior artery of arm, 561 
superior, 561 
vein, 631 
Promontory of tympanum, 827 
of sacrum, 153 
Pronator quadratus muscle, 443 
radii teres muscle, 440 
Pronephros, 133 
Pronucleus, female, 100 
male, 101 
Prosencephalon, 119 
Prostate gland, 962 
Prostate gland- 
landmarks of, 1047 
levator muscle of, 963, 1018 
lobes of, 963 
lymphatics of, 648 
surgical anatomy of, 1019 
vessels and nerves of, 963 
Prostatic plexus of nerves, 796 
of veins, 632 
portion of urethra, 959 
sinus, 959 
Protoplasm, 41 
Proto vertebrae, 106 
Proto vertebral somites, 106 
Protuberance, occipital, external. 
160 
internal, 163 
landmarks of, 1027 
Psoas magnus muscle, 463 
parvus, 464 
[Pterion, 684] 
Pterygo-maxillary fissure, 212 
ligament, 378 
Pterygo-palatine artery, 524 
canal, 178 
nerve, 727 
Pterygoid arteries, 524 
fossa of sphenoid, 179 
of lower jaw, 200 
muscles, 380 
nerve, 728 
notch, 179 
plexus of veins, 614 
process of palate bone, 194 
processes of sphenoid, 179 
ridge, 178 
Pubes, 264 
angle of, 265 
crest of, 265 
landmarks of, 1043 
spine of, 264 
symphysis of, 265, 321 
Pubic arch, 269 
articulations of, 321 
portion of fascia lata, 466 
Pubo-prostatic ligaments, 957 
Pudendum, 976 
Pudic artery in male, 588 
peculiarities of] 588 
accessory, 587 
deep external, 598 
in female, 589 
superficial external, 598 
nerve, 778 
vein, external, 630 
internal, 632 
Pulmonary artery, 502, 937 
opening of, in right ventri- 
cle, 909 
capillaries, 937 
nerves from vagus, 741 
sinuses, 911 
veins, 611, 612, 937 
openings of, left auricle, 911 
Pulp-cavity of tooth, 843 
of teeth, development of, 848 
Pulp of spleen, 900 
Pulse at wrist, landmarks of, 
1060 
Puncta vasculosa, 690 
lachrymalia, 822 
landmarks of, 1029 
Pupil of eye, 810 
membrane of, 812 
Purkinje, axis-cylinder of, 70 1092 
INDEX. 
Pyloric artery, 575 
inferior, 576 
plexus, 794 
Pylorus, 871 
landmarks of, 1045 
Pyramid in vestibule, 832 
of cerebellum, 710 
of thyroid gland, 940 
of tympanum, 827 
Pyramidali? muscle, 418 
nasi, 374 
Pyramids, anterior, 666 
decussation of, 666 
of Ferrein, 948 
of Malpighi, 946 
of the spine, 158 
posterior, 666 
Pyriformis muscle, 475 
Q. 
Quadrate lobe, 680 
Quadratus femoris muscle, 476 
lumborum, 418 
menti, 376 
Quadriceps extensor cruris mus- 
cle, 467 
Quadrigeminal bodies, 702 
R. 
Racemose glands, 97 
Radial artery, 562 
branches of, 563 
peculiarities of, 563 
surgical anatomy of, 563 
lymphatic glands, 643 
nerve, 7 93 
recurrent artery, 564 
region, muscles of, 444 
vein, 623 
Radialis indicis artery, 564 
Radio-carpal articulation, 335 
Radio-ulnar articulations, infe- 
rior, 333 
middle, 333 
superior, 333 
Radius, 248 
and ulna, fracture of, 460 
articulations of, 250 
development of, 249 
fracture of, 460 
grooves in lower end of, 249 
landmarks of, 1059 
muscles attached to, 250 
oblique line of, 248 
sigmoid cavity of, 249 
tuberosity of, 248 
Rami of the lower jaw, 199 
Ramus of ischium, 264 
descending, 265 
horizontal of pubes, 265 
of pubes, 265 
Ranine artery, 516 
vein, 614, 616 
Ranvier, nodes of, 70 
Raphe of corpus callosum, 692 
of palate, 850 
of perineum, 1013 
landmarks of, 1046 
of tongue, 799 
Receiving-tubes of kidney, 948 
Receptaculi arteriae, 530 
Receptaculum chyli, 639 
Recessus labvrinthi. 122 
Recto-uterine ligaments, 981 
Recto-vesical fascia, 1022 
fold, peritoneal, 957 
Rectum, 886 
development of, 130 
relations of, male, 886 
female, 886, 979 
folds of, 887 
landmarks of, 1047 
lymphatics of, 648 
palpation by, 1062 
Rectus abdominis, 417 
capitis anticus major, 397 
minor, 397 
femoris muscle, 467 
lateralis, 398 
oculi, internus, superior, infe- 
rior, and externus, 372 
posticus major, 410 
minor, 410 
Recurrent artery, interosseous, 
568 
radial, 564 
tibial, 605 
ulnar, anterior, 567 
posterior, 567 
laryngeal nerve, 740 
nerves to tentorium, 719 
Region, abdominal, 411 
acromial, muscles of, 432 
auricular, 369 
back, muscles of, 399 
brachial, anterior, 442 
posterior, 446 
cervical superficial, muscles of, 
382 
diaphragmatic, 422 
epicranial, muscles of, 366 
epigastric, 860 
femoral, muscles of, anterior, 
465 
internal, 470 
posterior, 477 
fibular, 486 
foot, dorsum of, 489 
sole of, 489 
gluteal, muscles of, 472 
groin, 991 
of hand, muscles of, 462 
humeral, anterior, 435 
posterior, 438 
hypochondriac, 860 
hypogastric, 860 
iliac, muscles of, 462 
infrahyoid, 386 
inguinal, 991 
intermaxillary, muscles of, 377 
ischio-rectal, 1010 
laryngo-tracheal, surgical 
anatomy of, 930 
lingual, muscles of, 389 
lumbar, 860 
maxillary, muscles of, inferior, 
376 
superior, 375 
nasal, muscles of, 374 
orbital, muscles of, 371 
palatal, muscles of, 394 
palpebral, 369 
perineum, 1012 
pharyngeal, muscles of, 392 
popliteal, 599 
pterygo-maxillary, muscles of, 
. 380 
radial, muscles of, 444 
Region- 
scapular, muscles of, anterior, 
433 
posterior, 433 
Scarpa's triangle, 594 
suprahyoid, muscles of, 388 
temporo-maxillary, muscles of, 
378 
thoracic, 419 
anterior, 427 
lateral, 430 
tibio-fibular, anterior, 479 
posterior, 481 
umbilical, 860 
vertebral, muscles of, anterior, 
397 
lateral, 398 
Regions of abdomen, 859 ■ 
Reil, island of, 677 
! Renal afferent vessels, 947, 951 
artery, 580, 949 
efferent vessels, 947, 951 
plexus, 794 
veins, 634, 951 
Respiration, organs of, 919 
muscles of, 421 
Respiratory nerves of Bell, ex*- 
ternal, 754 
internal, 752 
I Restiform bodies of medulla ob- 
longata, 666, 668 
1 Rete mucosum of skin, 89 
Malpighii, 90 
testis, 971 
Reticular cartilage, 53 
layer of skin, 91 
lamina of Kolliker, 836 
Retiform connective tissue, 48 
Retina, 812 
arteria centralis of, 532, 816 
fovea centralis of, 813 
limbus luteus of, 813 
membrana limitans of, 813 
layers of, 813 
structure of, 813 
Retinacula of ileo-csecal valve, 
883 
Retrahens aurem muscle, 369 
Rhomboid impression, 231 
ligament, 323 
Rhomboidal sinus, 118 
Rhomboideus, major, 403 
minor, 403 
Ribs, 224 
angle of, 226 
articulations of, 312 
attachment of muscles to, 228 
development of, 228 
false, 224 
floating, 225 
head of, 225 
landmarks of, 1034 
ligaments of, 313 
neck of, 225 
peculiar, 226 
true, 224 
tuberosity of, 225 
vertebral, 225 
vertebro-chondral. 225 
vertebro-sternal, 224 
Ridge, internal occipital, 162 
mylo-hyoidean, 199 
pterygoid, 178 • 
superciliary, 167 
temporal, 170, 211 INDEX. 
1093 
Rima glottidis, 923 
Ring, abdominal, external, 413, 
993 
internal, 996 
landmarks of, 1043 
femoral or crural, 1006 
landmarks of, 1048 
fibrous, of heart, 913 
Risorius muscle, 378 
Rivini, ducts of, 854 
Rods of Corti, 836 
Rolando, tubercle of, 669 
[fissure of, 675, 685] 
Root of lung, 936 
Roots of spinal nerves, 744 
of teeth, 841 
of zygomatic process, 171 
Rosenmuller, organ of, 135 
accessory gland of, 822 
Rostrum of sphenoid bone, 178 
of corpus callosum, 692 
Rotation, 300 
Rotatores spinae muscles, 409 
Round ligaments of uterus, 988 
relations of, to femoral 
ring, 1007 
of liver, 891 
Rugae of stomach, 872 
of vagina, 980 
Rupture of urethra, course taken 
by urine in, 1013 
S. 
Sac, lachrymal, 822 
landmarks of, 1029 
of omentum, 863 
Saccular secretory glands, 97 
Saccule of vestibule, 837 
Sacculus laryngis, 924 
Sacra-media artery, 582 
Sacral arteries, lateral, 591 
canal, 155 
cornua, 154 
foramina, 153 
ganglia, 792 
groove, 154 
lymphatic glands, 646 
nerves, 777 
plexus, 777 
vein, lateral, 632 
middle, 632 
Sacro-coccygeal ligaments, 320 
Sacro-iliac articulation, 319 
Sacro-lumbalis muscle, 406 
Sacro-sciatic foramen, greater, 
263, 320 
lesser 263, 320 
ligaments, 319, 320 
notch, greater, 263 
lesser, 263 
Sacro-vertebral angle, 153 
ligament, 318 
Sacrum, 152 
ala of, 155 
articulations of, 157 
attachment of muscles to, 157 
development of, 156 
peculiarities of, 156 
structure of, 155 
Sacs, dental, 847 
Sagittal suture, 203 
Salivary glands, 852 
structure of, 854 
Salpingo-pharyngeus, 396 
Santorini, cartilages of, 921 
Saphenous nerve, long or inter- 
nal, 774 
short, 781 
opening, 466, 1003 
vein, external or short, 631 
internal or long, 630, 1000 
Sarcolemma, 64 
Sarcous elements of muscle, 65 
Sartorius muscle, 467 
Scala tympani of cochlea, 834 
media, 834 
vestibuli of cochlea, 834 
Scalae of cochlea, 834 
Scalenus anticus, 398 
medius, 398 
posticus, 398 
Scalp, arteries of, 1026 
density of, 1026 
Scaphoid bone, hand, 250 
foot, 289 
fossa of sphenoid, 179 
Scapula, 233 
articulations of, 237 
attachment of muscles to, 237 
development of, 236 
dorsum of, 233 
glenoid cavity of, 236 
head of, 236 
landmarks of, 1040 
ligaments of, 326 
[mobility of, 329] 
muscles of, 433 
spine of, 233 
venter of, 233 
Scapular artery, posterior, 551 
region, muscles of, anterior, 433 
posterior, 433 
veins, 625 
Scapulo-clavicular articulation, 
324 
Scarfskin, 89 
Scarpa, foramina of, 190, 208 
Scarpa's triangle, 594 
Schachowa, spiral tubes of, 947 
Schindylesis, 298 
Schneiderian membrane, 803 
Schultze, cells of, 717, 804 
Schwann, white substance of, 70 
Sciatic artery, 590 
nerve, greater, 780 
lesser, 778 
veins, 632 
Sclerotic, 806 
Scrotal hernia, 998 
Scrotum, 967 
dartos of, 967 
development of, 138 
lymphatics of, 647 
nerves of, 969 
septum of, 968 
vessels of, 968 
Sebaceous glands, 94 
Second nerve, 717 
Secreting glands, 97 
Sella Turcica, 176, 206 
Semen, 973 
liquor seminis of, 973 
seminal granules of, 973 
spermatozoa of, 973 
Semicircular canals, 832 
Semilunar bone, 252 
cartilages of knee, 349 
fold of Douglas, 418 
fascia, 436 
Semilunar ganglion of fifth nerve, 
720 
of abdomen, 793 
valves, aortic, 912 
pulmonic, 910 
Semimembranosus muscle, 478 
Seminal granules, 973 
cells, 971 
tubes, 970 
vesicles, 972 
Semispinalis muscle, 409 
Semitendinosus muscle, 478 
Senac, on structure of heart's 
valves, 910 
Senses, organs of the, 798 
Septum auricularum, 911 
cartilage of, 803 
crurale, 1008 
lucidum, 697 
of medulla oblongata, 668 
of nose, 217 
pectiniforme, 965 
of pons Varolii, 672 
scroti, 967 
subarachnoid, 653 
of tongue, 801 
ventriculorum, 914 
Septum between bronchi, 928 
Serous glands of tongue, 800 
Serous membranes, 95 
Serratus magnus, 430 
posticus, inferior, 404 
superior, 404 
Serum, 39 
Sesamoid bones, 294 
cartilages, 803 
Seventh nerve, 732 
Shaft of a bone, its structure, 141 
Sheath of arteries, 80 
of muscles, 64 
of nerves, 73 
of rectus muscle, 417 
femoral or crural, 1004 
Short bones, 141 
Shoulder, muscles of, 429 
joint, 326 
landmarks of, 1057 
vessels and nerves of, 328 
Sigmoid artery, 579 
cavity, greater and lesser, of 
ulna, 245 
of radius, 249 
flexure of colon, 885 
mesocolon, 869 
notch of lower jaw, 200 
Sinus circularis iridis, 811 
of jugular vein, 616 
of kidney, 946 
pocularis, 959 
prostaticus, 135, 959 
Sinuses, cranial, 167, 612, 619 
cavernous, 621 
circular, 621 
of coronary vein, 637, 908 
ethmoidal, 183 
frontal, 168 
landmarks of, 1026 
of heart, of right auricle, 907 
of left, 911 
landmarks of cerebral, 1027 
lateral, 620 
longitudinal inferior, 620 
superior, 619 
of nose, 167 
occipital, 621 1094 
INDEX. 
Sinuses- 
maxillary, 187 
petrosal, inferior, 622 
superior, 622 
pulmonary, 911 
sphenoidal, 177 
straight, 620 
transverse, 622 
of Valsalva, aortic, 912 
Sixth nerve, 731 
Skeleton, 141 
number of its pieces, 141 
Skin, general anatomy of, 89 
appendages of, 92 
areolae of, 91 
corium of, 90 
cuticle of, 89 
derma, or true skin, 90 
development of, 123 
epidermis of, 89 
furrows of, 91 
hairs, 92 
muscular fibres of, 94 
nails, 92 
nerves of, 92 
papillary layer of, 91 
rete mucosum of, 89 
sebaceous glands of, 94 
sudoriferous or sweat-glands of, 
94 
tactile corpuscles of, 75 
vessels of, 91 
Skull, 160, 204 
anterior region, 213 
base of, external surface, 208 
internal surface, 205 
fossa of, anterior, 206 
middle, 206 
posterior, 207 
[landmarks on, 684] 
lateral region of, 211 
tables of, 141 
vertex of, 204 
vitreous table of, 142 
Skull-cap, thickness of. 1027 
Slender lobe of cerebellum, 710 
Small intestine, cellular coat of, 
877 
mucous coat of, 877 
muscular coat of, 876 
serous coat of, 876 
simple follicles, 879 
valvulse conniventes, 877 
villi of, 877 
Small intestines, 874 
duodenum, 874 
ileum, 876 
jejunum, 876 
Socia parotidis, 853 
Soft palate, 850 
aponeurosis of, 851 
arches or pillars of, 851 
muscles of, 394 
structure of, 851 
Solar plexus, 793 
[Sole of foot, imprint of, 294] 
muscles of, first layer, 489 
second layer, 491 
third layer, 492 
Soleus muscle, 482 
Solitary glands, 880 
Somatopleure, 106 
Sbmmerring, yellow spot of, 813 
Space, anterior perforated, 688 
axillary, 553 
Space- 
intercostal, 225 
popliteal, 600 
posterior perforated, 689 
Spaces of Fontana, 811 
Spermatic artery, 581, 968 
veins of, 968 
canal, 996 
cord, 968 
arteries of, 968 
landmarks of, 1044 
course of, 968 
fascia, external, 414, 993 
lymphatics of, 969 
nerves of, 969 
plexus of nerves, 794 
of veins, 633 
relation to femoral ring, 1007 
of, in inguinal canal, 968, 
996 
veins, 633, 968 
Sperm atoblasts, 971 
Spermatozoa, 973 
Spheno-maxillary fissure, 212 
fossa, 212 
Spheno-palatine artery, 525 
foramen, 195 
ganglion, 725 
nerves, 724 
notch, 195 
Spheno-parietal suture, 203 
Sphenoid bone, 176 
articulations of, 181 
attachment of muscles to, 181 
body of, 176 
development of, 180 
greater wings of, 178 
lesser wings of, 179 
pterygoid processes of, 179 
rostrum of, 178 
spinous processes of, 178 
vaginal processes of, 178 
Sphenoidal fissure, 179 
nerves in, 732 
process of palate, 195 
sinuses, 177 
turbinated bones, 180 
Sphincter muscle of bladder, 958 
of rectum, external, 1011 
internal, 1011 
of vagina, 1015 
white commissure of, 656 
matter of, 657 
Spinal arteries, anterior, 549 
lateral, 547 
median, 549 
posterior, 549 
canal, 160 
Spinal cord, 654 
arachnoid of, 653 
arrangement of gray and 
white matter in, 656 
central canal of, 661 
central ligament of, 654 
columns of, 655 
development of, 113 
dura mater of, 652 
fissures of, 655 
foetal, peculiarity of, 654 
gray commissure of, 655 
internal structure of, 656 
ligamentum denticulatum of, 
654 
membranes of, 652 
neuroglia of. 656 
Spinal cord- 
pia mater of, 654 
sections of; 655 
Spinal accessory nerve, 741 
Spinal nerves, 744 
arrangement into groups, 
744 
branches of, anterior, 745 
posterior, 745 
development of, 120 
landmarks of, 1038 
ganglia of, 745 
origin of, in cord, 660 
of roots, anterior, 744 
posterior, 744 
Spinal veins, 628 
longitudinal anterior, 629 
posterior, 629 
Spinalis colli muscle, 408 
dorsi, 408 
Spine, 142 
articulations of, 301 
development of, 113 
general description of, 158 
landmarks of, 1043 
ossification of, 150 
Spines of bones, ethmoidal, 176 
of ischium, 263 
nasal, 168 
anterior, 190 
posterior, 193 
pharyngeal, 162 
of pubes, 264 
of scapula, 233 
Spinous process of ilium, 261 
landmarks of, 1043, 1049 
of sphenoid, 178 
of tibia, 278 
of vertebrae, 143 
landmarks of, 1038 
Spiral canal of cochlea, 833 
Splanchnic nerve, greater, 791 
lesser, 791 
smallest or renal, 791 
Splanchnopleure, 106 
Spleen, 899 
artery of, 901 
capillaries of, 902 
fibro-elastic coat of, 900 
landmarks of, 1045 
lymphatics of, 649, 903 
Malpighian corpuscles of, 902 
nerves of, 903 
proper substance of, 900 
relations of, 899 
serous coat of, 900 
size and weight, 899 
structure of, 900 
trabeculae of, 900 
veins of, 903 
Splenic artery, 576 
distribution of, 902 
corpuscles, 902 
plexus, 793 
vein. 635 
Splenium of corpus callosum,* 
692 
Splenius muscle, 405 
Spongy portion of urethra, 960 
tissue of bone, 141 
Squamo-parietal suture, 203 
Squamo-sphenoidal suture, 203 
Squamous portion of temporal 
bone, 170 
Stapedius muscle, 831 INDEX. 
1095 
Stapes, 830 
annular ligament of, 830 
development of, 123 
Stellate ligament, 313 
plexus of kidney, 951 
Stenson, foramina of, 19 J, 208 
Stenson's duct, 853 
[Stephanion, 684] 
Sternal end of clavicle, fracture 
of, 457 
foramen, 224 
ligaments, 317 
nerves, 751 
Sterno-clavicular articulation, 
322 
Sterno-hyoid muscle, 386 
Sterno-mastoid muscle, 385 
artery, 519 
Sterno-thyroid muscle, 386 
Sternum, 220 
articulations of, 224 
attachment of muscles to, 224 
development of, 223 
landmarks of, 1034 
ligaments of, 317 
Stomach, 869 
alteration in position of, 870 
alveoli of, 872 
areolar coat of, 872 
cardia of, 869 
curvatures of, 869, 870 
development of, 130 
fundus of, 869 
gastric follicles of, 872 
landmarks of, 1045 
lenticular glands of, 873 
ligaments of, 870 
lymphatics of, 794 
mucous membrane of, 872 
muscular coat of, 869 
orifices of, 869 
peptic glands of, 872 
pyloric glands of, 872 
end of, 869 
pylorus, 871 
serous coat of, 871 
splenic end of, 869 
structure of, 871 
surfaces of, 870 
vessels and nerves of, 874 
Straight sinus, 620 
tubes of kidney, 948 
Stratiform fibro-cartilage, 53 
Stratum cinereum, 705 
corneum, 89 
lucidum, 90 
opticum, 706 
Striae longitudinales, 692 
laterales, 692 
of muscle, 66 
Striped muscle, 64 
Stroma of ovary, 985 
Stylo-glossus muscle, 392 
Stylo-hyoid ligament, 311 
muscle, 388 
nerve from facial, 735 
Stylo-mastoid artery, 520 
foramen, 174 
vein, 615 
Stylo-maxillary ligament, 311, 
384 
Stylo-pharyngeus muscle, 394 
Styloid process of temporal bone. 
174 
of radius, 249 
Styloid process of ulna, 247 
Subanconeus muscle, 438 
Subarachnoid space of brain, 
663 
of cord, 653 
fluid, 663 
septum, 653 
Subclavian arteries, 542 
branches of, 546 
first part of, left, 543 
right, 542 
peculiarities of, 544 
second portion of, 543 
surgical anatomy of, 544 
third, 544 
groove, 226 
nerve, 754 
triangle, 527 
vein, 625 
Subclavius muscle, 429 
Subcrureus muscle, 469 
Subdural space, 663 
Sublingual artery, 515 
fossa, 199 
gland, 854 
vessels and nerves of, 854 
Sublobular veins, 893 
Submaxillary artery, 518 
fossa, 199 
ganglion, 730 
gland, 853 
nerves of, 854 
vessels of, 854 
lymphatic gland, 640 
triangle, 526 
Submental artery, 518 
vein, 614 
Suboccipital nerve, 747 
posterior branch of, 747 
triangle, 547 
Subpeduncular lobe of cerebel- 
lum, 710 
Subpubic ligament, 321 
Subscapular aponeurosis, 433 
artery, 556 
fossa, 233 
nerves, 755 
Subscapularis muscle, 433 
Substantia cinerea gelatinosa, 
659 
perforata, 688 
Sudoriferous glands, 94 
Sulci of cerebrum, 673 
[Sulcus, inferior frontal, 676, 
686] 
[intraparietal, 676, 686] 
[precentral, 676, 686] 
spiralis, 835 
[superior frontal, 676, 686] 
[vertical, 676, 686] 
Supercilia, 819 
Superciliary ridge, 169 
Superficial palmar arch, 566 
cervical artery, 551 
circumflex iliac artery, 597 
perineal artbry, 589 
Superficialis colli nerve, 750 
voire artery, 564 
[Superior frontal sulcus, 676, 
686] 
maxillary bone, 186 
articulations of, 191 
attachment of muscles to, 
191 
development of, 190 
Superior maxillary nerve, 723 
meatus, 217, 804 
mediastinum, 934 
profunda artery, 561 
thyroid artery, 514 
turbinated crest, 189 
of palate, 194 
vena cava, 627 
Supinator brevis muscle, 447 
longus, 444 
Supraclavicular nerves, 751 
Suprahyoid aponeurosis, 388 
Supramarginal convolution, 676 
Supramaxillary nerves from fa- 
cial, 736 
Supraorbital arch, 167 
artery, 531 
foramen, 167, 213 
nerve, 721 
notch, 167 
Suprarenal arteries, 580 
capsules, 953 
development of, 134 
nerves of, 955 
vessels of, 954 
plexus, 794 
veins, 634 
Suprascapular artery, 550 
nerve, 755 
notch, 235 
Supraspinales muscles, 410 
Supraspinatus muscle, 433 
Supraspinous ligaments, 304 
aponeurosis, 433 
Supratrochlear foramen, 241 
nerve, 721 
Sural arteries, 602 
veins, 631 
[Surcingle, 693] 
Surgical anatomy, of abdominal 
aorta, 573 
of anterior tibial, 603 
of arch of aorta, 506 
of axilla, 553 
of axillary artery, 555 
of base of bladder, 1020 
of bend of elbow, 559 
of brachial artery, 560 
[of caecum and appendix, 
882] 
of common carotid artery. 
511 
iliac artery, 583 
of dorsalis pedis, 606 
of external carotid, 515 
iliac, 592 
of facial artery, 516 
of femoral artery, 596 
of femoral hernia, 1001 
of hamstring tendons, 479 
of iliac arteries, 530 
of inguinal hernia, 991 
of innominate artery, 509 
of internal carotid, 530 
of ischio-rectal region, 1010 
of laryngo-tracheal region, 
930 
of lingual artery, 516 
of muscles of eye, 373 
of lower extremity, 494 
of soft palate, 396 
of muscles of upper extrem- 
ity, 457 
of oesophagus, 857 
of perineum, 1012 1096 
INDEX. 
Surgical anatomy- 
of popliteal artery, 601 
of posterior tibial, 607 
of prostate gland, 1019 
of radial artery, 563 
of Scarpa's triangle, 594 
of stern o-mastoid muscle, 
386 
of subclavian artery, 544 
of superior thyroid, 515 
of talipes, 487 
of temporal artery, 521 
of thoracic aorta, 570 
of triangles of neck, 525 
of ulnar artery, 567 
Suspensory ligament of incus, 
830 
of lens, 818 
of liver, 889 
of malleus, 830 
of penis, 964 
Sustentacular cells of spleen, 
901 
Sustentaculum tali, 284 
Sutura, 298 
dentata, 298 
harmonia, 298 
limbosa, 298 
notha, 298 
serrata, 298 
squamosa, 298 
vera, 298 
Sutural ligament, 296 
Suture, basilar, 203 
coronal, 203 
cranial, 203 
ethmo-sphenoidal, 203 
ethmoido-frontal, 203 
frontal, 167, 170, 203 
fronto-parietal, 203 
fronto-sphenoidal, 203 
intermaxillary, 213 
internasal, 213 
interparietal, 203 
lambdoid, 203 
masto-occipital, 203 
masto-parietal, 203 
occipito-parietal, 203 
petro-occipital, 203 
petro-sphenoidal, 203 
sagittal, 203 
spheno-parietal, 203 
squamo-parietal, 203 
squamo-sphenoidal, 204 
temporal, 173 
transverse, 203 
Swallow's nest of cerebellum, 
710 
Sweat-glands, 94 
[Sylvian artery, 534, 537] 
[Sylvius, fissure of, 675, 686] 
aqueduct of, 701 
Sympathetic nerve, 74, 784 
cervical portion, 786 
cranial portion, 785 
lumbar portion, 792 
pelvic portion, 792 
thoracic portion. 791 
plexuses, 792 
cardiac, 792 
epigastric, 793 
hypogastric, 796 
pelvic, 796 
solar, 793 
Symphysis of jaw, 197 
Symphysis pubis, 265, 321 
Synarthrosis, 297 
Synovia, 297 
Synovial membrane, 96, 296 
articular, 297 
bursal, 297 
vaginal, 297. See also Individ- 
ual Joints. 
System, Haversian, 56 
Systemic arteries, 501 
veins, 611 
T. 
Tabatiere anatomique, 1060 
Tables of the skull, 141 
Tactile corpuscles, 75 
Taenia hippocampi, 695 
semicircular! s, 694 
violacea, 713 
Tapetum lucidum, 815 
nigrum, 815 
Tarinus, horny band of, 694 
Tarsal artery, 606 
bones, 284 
cartilages of eyelid, 820 
ligament of eyelid, 820 
ligaments, 358 
Tarso-metatarsal articulations. 
360 
Tarsus, 284 
articulations of, 357 
synovial membranes of, 360 
development of, 294 
Taste-goblets, 800 
Teeth, 840 
[apposition of, 843] 
bicuspid, 841 
body of, 841 
canine, 841 
cement of, 845 
crown of, 841 
crusta petrosa of, 845 
cortical substance of, 845 
cuspidate, 841 
deciduous, 843 
dental tubuli of, 844 
dentine of, 844 
development of, 846 
enamel of, 845 
eruption of, 849 
eye-, 841 
false molars, 841 
fang of, 841 
general characters of, 840 
growth of, 848 
incisors, 841 
intertubular substance of, 845 
ivorv of, 844 
milk, 840, 843 
molar, 841 
multicuspidate, 841 
[occlusion of, 843] 
permanent, 841 
pulp-cavity of, 843 
root of, 841 
[sixth-year molars, 850] 
structure of, 843 
temporary, 840, 843 
true or large molars, 841 
wisdom, 843 
Tegmentum of crus cerebri, 690, 
707 
Temporal artery, 521 
anterior, 521 
Temporal artery- 
deep, 524 
middle, 521 
posterior, 521 
surgical anatomy of, 521 
Temporal bone, 170 
articulations of, 176 
attachment of muscles to, 
176 
development of, 175 
mastoid portion, 171 
petrous portion, 173 
squamous portion, 170 
structure of, 175 
Temporal fascia, 379 
fossae, 211 
ganglion, 790 
muscle, 379 
nerves of auriculo-temporal, 
728 
deep, 728 
of facial, 729 
ridge, 168, 170, 211 
suture, 174 
veins, 614 
Temporary cartilage, 50 
teeth, 841, 843 
Temporo-facial nerve, 735 
Temporo-malar, 723 
Temporo-maxillary articulation, 
310 
Temporo-maxillary vein, 614 
Temporo-sphenoidal lobe, 677 
Tendo Achillis, 483 
landmarks of, 1054 
palpebrarum or oculi, 370 
Tendon, central, or cordiform, of 
diaphragm, 424 
conjoined of internal oblique 
and transversalis, 414, 994 
hamstring, 477 
landmarks of, 1052 
structure of, 364 
of wrist, 450 
Tenon, capsule of, 805 
Tensor palati muscle, 394 
tarsi muscle, 371 
tympani muscle, 830 
canal for, 175, 828 
vaginae femoris muscle, 466 
Tenth nerve, 738 
Tentorium cerebelli, 663 
Teres major muscle, 435 
minor, 434 
Testes, 969 
coni vasculosi of, 971 
coverings of, 969 
development of, 135 
gubernaculum testis, 974 
lobules of, 970 
lymphatics of, 648 
mode of descent, 974 
rete testis, 971 
size and weight of, 969 
structure of, 970 
tubuli seminiferi of, 970 
tunica albuginea, 970 
vaginalis, 969 
vasculosa, 970 
vasa efferentia of, 971 
vas aberrans of, 971 
vas deferens of, 972 
vas recta of, 971 
Thalamencephalon, 119 
Thalami optici, 699 INDEX. 
1097 
Thebesii venae, 637 
foramina, 637 
Theca vertebralis, 652 
Thigh, muscles of back, 477 
deep fascia, fascia lata, 465 
muscles of front of, 465 
superficial fascia, 465, 1000 
Third nerve, 718 
ventricle of the brain, 700 
[Thirteenth cranial nerve, 735] 
Thoracic aorta, 569 
surgical anatomy of, 570 
artery, acromial, 556 
alar, 556 
long, 556 
superior, 556 
duct, 639 
ganglia of sympathetic, 791 
nerves, anterior, 755 
posterior, or long, 754 
region, muscles of anterior, 427 
lateral, 430 
Thorax, general description of, 
904 
base of, 904 
bones of, 220 
boundaries of, 904 
cutaneous nerves of, anterior, 
766 
• lateral, 766 
fasciae of, 419 
lymphatics of, 649 
muscles of, 419 
parts passing through upper 
opening of, 904 
Throat, landmarks of, 1030 
Thumb, articulation of, with 
carpus, 338 
landmarks of, 1061 
muscles of, 452 
Thymus gland, 941 
lobes of, 941 
lymphatics of, 651 
Thyro-aryteenoideus muscle, 925 
Thyro-arytenoid ligament, in- 
ferior, 924 
superior, 924 
Thyro-epiglottic ligament, 922 
Thyro-epiglotiideus muscle, 926 
Thyro-hyoid ligaments, 921 
membrane, 921 
muscle, 387 
nerve, 743 
Thyroid artery, inferior, 550 
middle, 507 
superior, 514 
surgical anatomy of, 515 
branches of sympathetic, 790 
cartilage, 919 
landmarks of, 1032 
foramen, 266 
ganglion, 790 
gland, 939 
isthmus of, 940 
lymphatics of, 651 
veins, inferior, 627 
middle, 616 
superior, 616 
Tibia, 278 
articulations of, 281 
attachment of muscles to, 281 
crest of, 280 
development of, 281 
fracture of shaft of, 495 
landmarks of, 1051 
Tibia- 
nutrient artery of, 609 
spinous process of, 278 
tubercle of, 279 
tuberosities of, 278 
Tibial artery, anterior, 603 
branches of, 605 
peculiarities of, 603 
surgical anatomy of, 603 
posterior, 607 
branches of, 608 
peculiarities of, 607 
surgical anatomy of, 607 
lymphatic glands, 644 
nerve, anterior, 782 
posterior, 781 
recurrent artery, 605 
veins, anterior, 631 
posterior, 631 
Tibialis anticus muscle, 479 
posticus muscle, 485 
Tibio-fibular articulations, 353 
region, anterior, muscles of, 
479. 
posterior, 481 
Tibio-tarsal ligament, 354 
Tongue, 798 
arteries of, 801 
fibrous septum of, 801 
frsenum of, 799 
mucous glands of, 800 
mucous membrane of, 799 
muscles of, 391 
nerves of, 801 
papillae of, 799 
serous glands of, 800 
Tonsillar nerves, 738 
artery, 518 
Tonsils, 851 
of cerebellum, 710 
landmarks of, 1031 
nerves of, 852 
vessels of, 852 
Torcular Herophili, 163, 620 
Trabeculae of corpus cavernosum, 
965 
of foetal skull, 116 
of spleen, 900 
of testis, 970 
Trachea, 927 
cartilages of, 929 
glands of, 929 
landmarks of, 1032 
relations of, 927 
structure of, 929 
surgical anatomy of, 930 
vessels and nerves of, 930 
Trachelo-mastoid muscle, 408 
Tracheotomy, 930 
Trachoma glands, 821 
Tractus intermedio-lateralis, 660 
opticus, 717 
Tragicus muscle, 824 
Tragus, 823 
Transversalis fascia, 996 
muscle, 415 
colli artery, 551 
muscle, 406 
Transverse arteries of basilar, 
549 
colon, 883 
facial artery, 521 
vein, 614 
fissure of brain, 697 
of liver, 891 
Transverse ligament of atlas, 
307 
of hip, 341 
of knee, 347 
of scapula, 326 
tibio-fibular, 354 
mesocolon, 869 
process of a vertebra, 143 
sinus, 622 
suture, 204 
Transversus auriculae, 824 
pedis, 492 
perinaei, 1014 
(in female), 1015 
Trapezium bone, 252 
of pons, 672 
Trapezius muscle, 400 
Trapezoid bone, 254 
ligament, 524 
Triangle, inferior carotid, 525 
of elbow, 559 
[of election, 526] 
of Hesselbach, 999 
[of necessity, 525] 
of neck, anterior, 525 
posterior, 527 
occipital, 527 
Scarpa's, 594 
subclavian, 527 
submaxillary, 526 
suboccipital, 547 
superior carotid, 526 
Triangular ligament of abdomen, 
413, 994 
of urethra, 1015 
interarticular fibro-cartilage, 
334 
Triangularis sterni muscle, 420 
Triceps extensor cruris, 468 
extensor' cubiti, 438 
Tricuspid valves, 909 
Trifacial or trigeminus nerves, 
719 
Trigone of bladder, 958 
landmarks of, 1046 
Trochanter, greater, 271 
lesser, 272 
landmarks of, 1049 
Trochanteric fossa, 271 
Trochlea of humerus, 241 
Trochlear nerve, 719 
True pelvis, 268 
corpus luteum, 987 
ligaments of bladder, 957 
ribs, 224 
Trunk, articulations of, 301 
muscles of, 399 
Tube, Eustachian, 828 
Fallopian, 984 
Tuber cinereum, 689 
ischii, 264 
Tubercle of the clavicle, 230 
of the femur, 272 
genital, 138 
lachrymal, 189 
laminated, of cerebellum, 710 
of Lower, 908 
for odontoid ligaments, 161 
of Rolando, 669 
of scaphoid of carpus, 250 
of tarsus, 289 
of the tibia, 279 
of ulna, 243 
of zygoma, 171 
Tubercles, genial, 199 1098 
INDEX. 
Tubercles- 
of ribs, 225 
Tubercula quadrigemina, 702 
Tuberosities of humerus, greater 
and lesser, 238 
of tibia, 278 
Tuberosity of ischium, 264 
maxillary, 187 
of palate bone, 195 
of radius, 248 
Tubes, bronchial, 927 
structure of, in lung, 937 
Tubular secreting glands, 97 
Tubular substance of kidney, 
946 
Tubuli, dental, 844 
of Ferrein, 948 
lactiferi, 989 
seminiferi, 970 
uriniferi, 946 
Tuft, vascular, in Malpighian 
bodies of kidney, 946 
Tunica albuginea, 970 
of eye, 372 
of ovary, 986 
reflexa, 970 
Ruyschiana, 810 
vaginalis, 969 
propria, 970 
oculi, 805 
vasculosa testis, 970 
Turbinated bone, superior, 183 
inferior, 196 
middle, 182 
Tutamina oculi, 819 
Twelfth nerve, 742 
Tympanic artery, from internal 
carotid, 530 
from internal maxillary, 
523 
bone, 175 
nerve, 738, 831 
of facial, 734 
plate, 171 
plexus, 788 
ring, 175 
Tympanum, 826 
arteries of, 831 
cavity of, 826 
membrane of, 829 
mucous membrane of, 831 
muscles of, 830 
nerves of, 831 
ossicula of, 830 
veins of, 831 
Tyson's glands, 964 
U. 
Ulna, 243 
articulations of, 247 
coronoid process of, 243 
development of, 247 
fract ure of coronoid process of, 
459 
of olecranon, 459 
of shaft, 460 
landmarks of, 1059 
muscles attached to, 247 
olecranon, process of, 243 
sigmoid cavities of, 245 
styloid process of, 247 
tubercle of, 243 
Ulnar artery, 566 
branches of, 567 
peculiarities of, 567 
Ulnar artery- 
recurrent, anterior, 567 
surgical anatomy of, 567 
lymphatic glands, 644 
nerve, 561 
posterior, 567 
vein, anterior, 623 
posterior, 623 
Umbilical arteries in foetus, 126, 
916 
how obliterated, 918 
cord, 113 
fissure of liver, 891 
region, contents of, 860 
vein, 126 
how obliterated, 916 
vesicle, 107 
Umbilicus, 107, 418 
landmarks of, 1041 
Unciform bone, 255 
process of ethmoid, 182 
Uncinate lobe, 680 
Ungual phalanges, 258 
Unstriped muscle, 67 
Upper extremity, arteries of, 541 
bones of, 229 
fascia of, 425 
ligaments of, 322 
lymphatics of, 643 
muscles of, 425 
nerves of, 755 
surgical anatomy of, 457 
veins of, 623 
Urachus, 955 
Ureters, 952 
muscles of, 952 
nerves of, 953 
vessels of, 953 
Urethra, development of, 138 
in the child, 1048 
bulbous portion of, 960 
caput gallinaginis, 959 
female, 978 
landmarks of, 1047 
male, 959 
membranous portion, 960 
prostatic portion, 959 
rupture of, course taken by 
urine, 1014 
sinus of, 959 
pocularis of, 959 
spongy portion of, 960 
structure of, 960 
verumontanum, 959 
Urinary organs, 944 
development of, 132 
Urogenital sinus, 138 
Uterine arteries, 586 
plexus, 797 
of veins, 632 
Uterus, 980 
appendages of, 984 
arbor vitfe of, 981 
broad ligaments of, 981 
cavity of, 981 
development of, 136 
dimensions, 981 
ganglia of, 797 
nerves of, 797 
in foetus, 983 
fundus, body, and cervix of, 981 
ligaments of, 981 
lymphatics of, 648 
masculinus, or utriculus hom- 
inis, 135, 960 
Uterus- 
during menstruation, 983 
nerves of, 983 
in old age, 983 
after parturition, 983 
during pregnancy, 983 
at puberty, 983 
round ligaments of, 988 
shape, position, 980 
structure of, 981 
vessels, 983 
Utricle of vestibule, 837 
Uvea, 811 
Uvula of throat, 851 
of cerebellum, 710 
vesica?, 959 
V. 
Vagina, 979 
columns of, 980 
lymphatics of, 648 
orifice of, 977 
Vaginal arteries, 586 
plexus of nerves, 797 
of veins, 632 
portal plexus, 894 
process of temporal, 171, 174 
processes of sphenoid, 178 
synovial membranes, 297 
Vagus nerve, 738 
ganglion of root of, 739 
of trunk of, 739 
Valley of cerebellum, 709 
Valsalva, sinuses of, 504, 911, 
912 
Valve of Bauhin, 882 
coronary, 908 
of cystic duct, 896 
Eustachian, 908 
of gall-bladder, 896 
of Hasner, 822 
ileo-ceecal, 882 
of Kerkring, 877 
mitral, 912 
of Vieussens, 703 
Valves in right auricle, 908 
of lymphatics, 85 
pulmonic, 909 
semilunar aortic, 912 
tricuspid, 909 
of veins, 84 
Valvulse conniventes, 877 
Vas aberrans, 971 
deferens, 972 
structure of, 972 
Vasa aberrantia, from brachial 
artery, 560 
afferentia of lymphatic glands, 
639 
brevia arteries, 577 
veins, 635 
efferentia of testis, 971 
of lymphatic glands, 639 
intestini tenuis arteries, 577 
recta, 971 
vasorum of arteries, 80 
of veins, 84 
Vascular system, general anat- 
omy of, 78 
changes in, at birth, 918 
peculiarities in the foetus, 
915 
Vastus externus muscle, 468 
internus and crureus, 468 INDEX. 
1099 
Veins, general anatomy of, 83 
anastomoses of, 611 
coats of, 84 
development of, 128 
muscular tissue of, 83 
plexuses of, 611 
size, form, etc., 611 
structure of, 84 
valves of, 84 
vessels and nerves of, 84 
Veins or vein, descriptive anat- 
omy of, 612 
of alee nasi, 614 
angular, 614 
articular of knee, 631 
auditory, 838 
auricular anterior, 614 
posterior, 615 
axillary, 625 
azygos, left lower, 628 
left upper, 628 
right, 627 
basilic, 624 
basi-vertebral, 629 
of bone, 55 
brachial, 625 
brachio-cephalic or innomin 
ate, 625 
bronchial, 628 
buccal, 614 
cardiac, 636 
anterior, 636 
great, 636 
posterior, 636 
cardinal, 129 
cava superior, 627 
inferior, 633 
cephalic, 624 
cerebellar, 619 
cerebral, 618 
cervical, ascending, 617 
deep, 617 
choroid of brain, 619 
circumflex, iliac, 631 
superficial, 630 
condyloid posterior, 617, 620 
of corpora cavernosa, 965 
of corpus spongiosum, 632 
of corpus striatum, 618 
cystic, 636 
deep, or venae comites, 611 
dental inferior, 614 
digital of hand, 624 
of diploe, 617 
dorsalis nasi, 614 
pedis, 631 
dorsi-spinal, 628 
of penis, 632 
epigastric, 631 
superficial, 630 
of eyeball, 819 
facial, 613 
femoral, 631 
frontal, 613 
of Galen, 618 
gastric, 635 
gastro-epiploic, 635 
gluteal, 632 
hemorrhoidal, 632 
of head, 612 
hepatic, 634 
iliac, common, 632 
external, 631 
internal, 631 
ilio-lumbar, 632 
Veins or vein-■ 
inferior cava, 633 
innominate, 625 
intercostal, superior, 625 
interlobular, of kidney, 951 
of liver, 893 
interosseous of forearm, 624 
intralobular of liver, 893 
jugular, anterior, 615 
external, 615 
posterior, 615 
internal, 616 
of kidney, 949 
labial, inferior, 614 
superior, 614 
laryngeal, 627 
lateral sacral, 632 
lingual, 616 
of liver, 894 
longitudinal inferior, 620 
lumbar, 633 
ascending, 633 
mammary internal, 626 
masseteric, 614 
mastoid, 615 
maxillary internal, 614 
median cutaneous, 624 
basilic, 624 
cephalic, 624 
medulli-spinal, 629 
meningeal, 614 
meningo-rachidian, 628 
mesenteric inferior, 634 
superior, 634 
nasal, 614 
oblique, 637 
obturator, 632 
occipital, 615 
oesophageal, 627 
ophthalmic, 621 
ovarian, 634 
palatine, inferior, 614 
palmar, deep, 625 
palpebral, inferior, 614 
superior, 614 
pancreatic, 635 
pancreatico-duodenal, 635 
parotid, 614 
peroneal, 631 
pharyngeal, 616 
phrenic, 634 
plantar, external, 631 
internal, 631 
popliteal, 631 
portal, 611, 636, 894 
profunda femoris, 631 
pterygoid plexus, 614 
pudic, external, 630 
internal, 632 
pulmonary, 612 
radial, 623 
ranine. 614, 616 
renal, 634, 949 
sacral, middle, 632 
lateral, 632 
Salvatella, 623 
saphenous, external, or short. 
631 
internal, or long, 630, 1000 
landmarks of, 1057 
sciatic, 632 
spermatic, 633 
spheno-palatine, 616 
spinal, 628 
splenic, 635 
Veins or vein- 
stylo-mastoid, 615 
subclavian, 625 
sublobular, 893, 894 
submaxillary, 614 
submental, 614 
superficial, 611 
supraorbital, 614 
suprarenal, 634 
suprascapular, 615 
sural, 631 
systemic, 611 
temporal, 614 
middle, 614 
temporo-maxillary, 614 
thyroid inferior, 626 
middle, 616 
superior, 616 
tibial anterior, 631 
posterior, 631 
transverse cervical, 615 
facial, 613 
ulnar anterior, 623 
deep, 624 
posterior, 623 
umbilical, 916 
vaginal of liver, 894 
vasa brevia, 635 
vertebral, 616 
Vidian, 616 
Veins, plexuses of, ovarian, 634. 
988 
pampiniform, 633, 968, 988 
pharyngeal, 616 
pterygoid, 614 
spermatic, 633, 968 
uterine, 632 
vaginal, 632 
vesico-prostatic, 632 
Velum pendulum palati, 850 
interpositum, 699 
Vena cava, superior, 627 
foetal, 129 
inferior, 633 
Venae comites, 611 
hepaticae revehentes, 128 
advehentes, 128 
interlobulares of kidney, 950 
rectae of kidney, 951 
Thebesii, or minimae cordis, 
637, 915 
vorticosae, 809 
Venter of ilium, 261 
of scapula, 233 
Ventricle of Arantius, 667 
[of the cord, 656, 661, 667] 
Ventricles of brain, third, 700 
fourth, 712 
fifth, 697 
[sixth, 656, 661, 667] 
lateral, 692 
lining membrane of, 714 
of corpus callosum, 691 
of heart, left, 912 
right, 909 
of larynx, 924 
Vermiform process of cerebellum, 
inferior, 710 
superior, 708 
I Vernix caseosa, 123 
i Vertebra prominens, 147 
development of, 152 
Vertebrae, 142 
cervical, 143 
I development of, 150 1100 
INDEX. 
Vertebrae- 
dorsal, 147 
general characters, 143 
ligaments of, 301 
lumbar, 149 
movements of, 1039 
sacral, 152 
spines of, 1037 
landmarks of, 1037 
structure of, 150 
Vertebral aponeurosis, 405 
artery, 546 
column, 158 
articulation of, 301 
ossification of, 150 
foramen, 144 
ligaments, 302 
region, muscles of, anterior, 
397 
lateral, 398 
ribs, 225 
vein, 616 
Vertebro-chondral ribs, 225 
Vertebro-sternal ribs, 224 
Vertex of skull, 204 
Vertical plate of palate bone, 
194 
[sulcus, 676, 686] 
Verumontanum, 959 
Vesical artery, inferior, 586 
middle, 586 
superior, 586 
plexus of nerves, 796 
Vesicle, auditory, 122 
cerebral, 118 
germinal, 100 
ocular, 121 
of Purkinje, 99 
umbilical, 107 
Vesicles, Graafian, 986 
Vesico-prostatic plexus of veins, 
632 
Vesico-uterine ligaments, 981 
Vesicula prostatica, 959 
Vesiculae seminales, 972 
vessels and nerves of, 973 
Vesicular nervous matter, 68 
Vestibular artery, 838 
nerve, 838 
Vestibule of ear, 832 
Vestibule of ear-- 
aqueduct of, 174, 832 
of vulva, 977 
Vestigial fold of pericardium, 
626 
Vibrissae, 802 
Vidian artery, 524 
canal, 180 
nerve, 727 
Vieussens, valve of, 703 
Villi, 877 
Viscera, position of, in abdom- 
, inal regions, 860 
landmarks of, 1044 
pelvic, position of, at outlet of 
pelvis, 1017 
Visceral arches (foetal), 117 
Vitelline membrane, 99 
circulation, 124 
spheres, 101 
Vitellus, 99 
Vitreous humor of the eye, 817 
table of the skull, 142 
Vocal chords, inferior or true, 
924 
superior or false, 923 
Voice, organs of, 919 
Voluntary muscles, 64 
Vomer, 197 
alee of, 197 
articulations of, 197 
development of, 197 
Vortex of heart, 914 
Vulva, 976 
development of, 138 
w. 
Wagner, tactile corpuscles of, 75 
Waters, Dr., researches on the 
lung, 937 
Watney on the structure of villi, 
877 
of thymus, 942 
Weight of organs. See Individ- 
ual Organs. 
Wharton's duct, 853 
White substance of cord, 657 
of Schwann, 70 
nerve-substance, 69 
White fibrous tissue, 45 
Willis, circle of, 550 
Winslow, foramen of, 861 
ligament of, 347 
Wisdom tooth, 843 
Wolffian body, 133 
Womb. See Uterus. 
Wormian bones, 184 
[Wrinkles of forehead, 368, 
371] 
Wrisberg, cartilages of, 921 
ganglion of, 793 
nerve of, 7 57 
Wrist-joint, 335 
landmarks of, 1060 
Wry-neck, 386 
X. 
Xiphoid appendix, 222 
Y. 
Y-ligament, 344 
Y-shaped centre of acetabulum, 
266 
Yellow elastic fibrous tissue, 46 
cartilage, 53 
spot of retina, 813 
Yolk, 100 
cleavage of, 101 
Z. 
Zinn, ligament of, 372 
Zona fasciculata, 953 
glomerulosa, 953 
pellucida, 99 
reticularis, 953 
vasculosa, 986 
Zygoma, 170 
roots of, 171 
tubercle of, 171 
Zygomatic arch, 212 
fossae, 212 
lymphatic glands, 640 
process, 193 
Zygomaticus major muscle, 375 
minor, 375 
THE END. CLASSTFT.ET) LIST 
OF 
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HIRST & PIERSOL on Human Monstrosities Mag- 
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ALLEN'S System of Human Anatomy, Including its Medi- 
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students of medicine. With an introductory section on 
Histology, by E. O. Shakespeare, M. D. In six sections, 
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text. Price per section, in handsome portfolio, $3.50. Also 
bound, in cloth, $23.00; half Russia, raised bands and open 
back, $25.00. 
TREVES' Surgical Applied Anatomy. In one 12mo. vol- 
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Students' Series of Manuals, page 1. 
CLARKE & LOCKWOOD'S Dissectors' Manual. In 
one 12mo. volume of 396 pages, with 49 illustrations. Cloth, 
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Cloth, $4.00; leather, $5.00. 
ELLIS' Demonstrations in Anatomy; Being a Guide to the 
Knowledge of the Human Body by Dissection. From the 
eighth and revised English edition. In one very handsome 
octavo volume of 716 pages, with 249 illustrations. Cloth, 
$4.25; leather, $5.25. 
ROBERTS' Compend of Anatomy. In one 16mo. volume 
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CLELAND'S Directory for the Dissection of the Human 
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HOLDEN'S Landmarks, Medical and Surgical. A new 
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HORNER'S Special Anatomy and Histology. Cloth, $6.00. 
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BELLAMY'S Student's Guide to Surgical Anatomy. In 
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ANATOMY. 
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ored plates of deposits. Cloth, $3.25. 
VAUGHAN & NOVY on Ptomaines and Leucomaines 
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Preparations. Third edition, thoroughly rewritten. In 
one octavo volume of 621 pages, with 179 illustrations. 
Cloth, $4.25. 
CHARLES' Physiological and Pathological Chemistry. 
In one 8vo. volume of 463 pages, with 38 illustrations and 
1 colored plate. Cloth. $3.50. 
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CLOWES' Elementary Treatise on Practical Chemistry 
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CLASSEN'S Elementary Quantitative Analysis. Trans- 
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RALFE'S Clinical Chemistry. In one 12mo. volume of 314 
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GREENE'S Manual of Medical Chemistry. In one 12mo. 
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WOHLER & FITTIG'S Outlines of Organic Chemistry. 
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CHEMISTRY-continued. 
DICTIONARIES. 
THE NATIONAL Medical Dictionary. Including in one 
alphabet all current medical terms in English, French, 
German, Italian and Latin, with definition, pronunciation, 
accentuation and synonyms, and a series of tables of useful 
data. By John S. Billings, M. D., LL. D., D. C. L. In 
two very handsome royal octavo volumes containing 1574 
pages. Per volume, cloth, $6.00; leather, $7.00; half 
Morocco, $8.50. For sale by subscription only. Specimen 
pages on application. Address the publishers. 
DUNGLISON'S Medical Lexicon; A Dictionary of Medi- 
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ous Subjects and Terms of Anatomy, Physiology, Pathology, 
Hygiene, Therapeutics, Pharmacology, Pharmacy, Sur- 
gery, Obstetrics, Medical Jurisprudence, and Dentistry; 
Notices of Climate and of Mineral Waters; Formulae for 
Officinal, Empirical and Dietetic Preparations; with the 
Accentuation and Etymology of the Terms, and the French 
and other Synonymes-so as to constitute a French as well 
as an English Medical Lexicon. By Robley Dunglison, 
M. D. Edited by Richard J. Dunglison, M. D. In one 
very large and handsome royal octavo volume of 1139 
pages. Cloth, $6.50; leather, raised bands, $7.50. 
HOBLYN'S Dictionary of the Terms used in Medicine and 
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520 double-columned pages. Cloth, $1.50; leather, $2.00. 
CHAPMAN'S Text-book of Human Physiology. Very 
handsome octavo volume of 925 pages, with 605 engrav- 
ings. Cloth, $5.50; leather, $6.50. 
DALTON'S Treatise on Human Physiology. Designed for 
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ume ot 722 pages, with 252 illustrations on wood. Cloth, 
$5.00; leather, $6.00. 
FOSTER'S Text-book of Physiology. New (fourth) Ameri- 
can edition. In one 8vo. volume of 1054 pages, with 282 
illustrations. Cloth, $4.50; leather, $5.50. 
POWER'S Human Physiology. Second edition. In one 
12mo. volume of 396 pages, with 47 illustrations. Cloth, 
$1.50. See Students' Series of Manuals, page 1. 
BELL'S Comparative Anatomy and Physiology. In one 
12mo. volume of 561 pages, with 229 illustrations. Cloth, 
$2.00. See Students' Series of Manuals, page 1. 
ROBERTSON'S Physiological Physics. In one 12mo.vol- 
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Students' Series of Manuals, page 1. 
DRAPER'S Medical Physics. In one octavo volume of 
734 pages, with 376 illustrations. Cloth, $4.00. 
CARPENTER'S Principles of Human Physiology. Eighth 
edition. Octavo. 
DALTON'S Circulation of the Blood. In one 12mo. vol- 
ume of 293 pages. Cloth, $2.00. 
LEHMANN'S Manual of Chemical Physiology. Cloth,$2.25. 
PHYSIOLOGY. 
MANUALS. 
THE STUDENTS' QUIZ SERIES. For Students and 
Practitioners. In form of question and answer. With 
many illustrations. Comprising thirteen separate volumes, 
handsomely bound in cloth, as follows: 1. Anatomy (double 
number); 2. Physiology; 3. Chemistry and Physics; 4. Pa- 
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and Therapeutics; 6. Practice of Medicine; 7. Surgery 
(double number); 8. Genite-Urinary and Venereal Dis- 
eases ; 9. Diseases of the Skin; 10. Diseases of the Eye, Ear, 
Throat and Nose; 11. Obstetrics; 12. Diseases of Women; 
13. Diseases of Children Nos 1, 3, 4,5, 6, 8, 9,11 and 12 ready 
shortly. The remaining volumes ready in the early fall. Full 
circular, with specimen pages, on application to publishers. 
STUDENTS' Series of Manuals. A series of manuals 
by eminent teachers or examiners. Pocket-size 12mos. of 
300-540 pages, richly illustrated. The following are now 
ready: Luff's Manual of Chemistry, $2; Herman's 
First Lines in Midwifery, $1.25; Tbeves' Manual 
of Surgery, in three volumes, per set, $6; Klein's 
Histology (4th Ed.), $1.75; Pepper's Surgical Pa- 
thology, $2; Treves' Surgical Applied Anatomy, 
$2; Power's Human Physiology (2d Ed.), $1.50; Ralfe's 
Clinical Chemistry, $1.50; Clarke & Lockwood's 
Dissectors' Manual, $1.50; Bruce's Matebia Medica 
and Therapeutics (4th Ed.), $1.50; Robertson's Physi- 
ological Physics, $2; Gould's Surgical Diagnosis, 
$2; and Bell's Comparative Physiology and Anat- 
omy, $2. Pepper's Forensic Medicine {shortly). For 
separate notices see various subject-heads. 
BLOXAM'S Chemistry, Inorganic and Organic. New 
American from the filth London edition. In one very 
handsome octavo volume of 727 pages,with 292 illustrations. 
Cloth, $2.00; leather, $3.00. 
FOWNES' Manual of Chemistry; Theoretical and Prac- 
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In one large royal 12mo. volume of 1061 pages, with a 
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leather, $3.25. 
ATTFIELD'S Chemistry, General, Medical and Pharma- 
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poeia. A Manual of the General Principles of the Science 
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one very handsome 12mo. volume of 774 pages, with 88 
illustrations. Cloth, $2.75; leather, $3.25. 
REMSEN'S Theoretical Chemistry. With special reference 
to the Constitution of Chemical Compounds. New (4th) edi- 
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CHEMISTRY. 
(8. 15. 2.) LEA BROTHERS & CO., PUBLISHERS, PHILADELPHIA. 2 
Condensed List of Lea Brothers & Co.'s Medical Works. 
HARTSHORNE'S Conspectus of the Medical Sciences; 
containing Handbooks on Anatomy, Physiology, Chem- 
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Obstetrics. In one large royal 12mo. volume of 1028 closely- 
printed pages, with 477 illus. Cloth, $4.25; leather, $5.00. 
SERIES of Clinical Manuals. A collection of authorititive 
monographs in a cheap and portable form. The following 
volumes are now ready: Yeo on Food in Health and 
Disease, $2; Broadbent on the Pulse, $1.75; Ballon 
Diseases of the Rectum and Anus, $2.25; Carter <fc 
Frost's Ophthalmic Surgery, $2.25; Hutchinson on 
Syphilis, $2.25; Marsh on Diseases of the Joints, 
$2: Morris on Surgical Diseases of the Kidney, 
$2.25; Owen on Surgical Dis bases of Children, $2; 
Butltn on the Tongue. $3.50; Pick on Fractures 
and Dislocations, $2: Savage on Insanity and 
Allied Neuroses, $2; and Treves on Intestinal 
Obstruction $2. The following is in press: Lucas on 
Diseases of the Urethra. For separate notices see 
various subject-heads. 
LUDLOW'S Manual of .Examinations upon Anatomy, 
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Materia Medica, Chemistry, Pharmacy and Therapeutics. 
To which is added a Medical Formulary. In one handsome 
royal 12mo. volume of 816 pages, with 370 illustrations. 
Cloth, $3.25; leather, $3.75. 
MANUALS-continued. 
HARE'S System of Practical Therapeutics. By American 
and Foreign Authors. Edited by Hobart Amory Hare, 
M. D. In three large octavo volumes of over 1000 pages 
each, fully illustrated. Third and final volume just ready. 
Per volume, cloth, $5; leather, $6; half Russia, $7. For sale 
by subscription only. Address the publishers. 
BRISTOWE'S Treatise on the Science and Practice of 
Medicine. Seventh edition. In one large octavo volume 
of 1325 pages. Cloth, $6.50; leather, $7.50. 
A SYSTEM of Practical Medicine, by American Authors. 
Edited by William Pepper, M. D., LL. D. Complete 
work now ready. In five royal octavo volumes, con- 
taining 5573 pages, with 198 illustrations. Per volume, 
cloth, $5.00; leather, $6.00; half Russia, $7.00. For sale by 
subscription only. 
FLINT'S Treatise on the Principles and Practice of Medi- 
cine; designed for the use of Students and Practitioners 
of Medicine. Sixth edition. Thoroughly revised by 
the Author, assisted by William H. Welch, M. D., and 
Austin Flint, Jr., M. D. In one large and closely-printed 
octavo volume of 1160 pages, with 5 woodcuts. Cloth, $5.50; 
strongly bound in leather, with raised bands, $6.50. 
LYMAN'S Practice of Medicine. In one octavo volume of 
900 pages, with Illustrations. Ready in a few days. 
REYNOLDS' System of Medicine. Edited by H. Harts- 
horne, M.D. In three large octavo volumes of 3056 closely- 
printed double-columned pages, with 317 illustrations. Per 
volume in cloth, $5.00; in leather, $6.00; half Russia, $6.50. 
Sold only by subscription. 
WHITLA'S Dictionary of Treatment, or Therapeutic In- 
dex, Including Medical and Surgical Therapeutics. In one 
octavo volume of 917 pages. Cloth, $4. 
HARTSHORNE'S Essentials of the Principles and Prac- 
tice of Medicine. A Handbook for Students and Practi- 
tioners. Fifth edition, revised and improved. In one 
handsome royal 12mo. volume of 669 pages, with 144 illus- 
trations. Cloth, $2.75; half bound, $3.00. 
FOTH ERGILL'S Practitioner's Handbook of Treatment; 
or, The Principles of Therapeutics. Third edition. In one 
very handsome octavo volume of 661 pages. Cloth, $3.75; 
leather, $4.75. 
COHEN'S Handbook of Applied Therapeutics. In one 
large 12mo. volume, with illustrations. Preparing. 
MUSSER'S Medical Diagnosis. In one volume of about 
600 pages. Preparing. 
BROWNE on Koch's Remedy in Relation Specially to 
Throat Consumption In one 12mo. volume of 121 pages, 
with 45 illustrations. Cloth, $1.50. 
THE YEAR-BOOK of Treatment for 1892. A CriticalRe- 
view for Practitioners of Medicine and Surgery. A classi- 
fied summary of medical progress by 21 eminent physicians 
and surgeons. In one 12mo. volume of about 500 pages. 
Cloth, $1.50. For Commutation Rates with Periodicals, 
see page 4. 
THE YEAR-BOOK of Treatment for 1891, similar to 
above, 485 pages. Cloth, $1.50. 
THE YEAR-BOOKS of Treatment for 1886,1887 and 1890. 
Similar to above. 12mo., 320 pages. Each, cloth, $1.25. 
WATSON'S Lectures on the Principles and Practice of 
Physic. A new American from the fifth revised English 
edition. Edited, with additions, and several hundred illus- 
trations, by Henry Hartshorne, M. D. In two large 
octavo volumes of 1840 pages, with 190 woodcuts. Cloth, 
$9.00; leather, $11.00. 
RICHARDSON'S Preventive Medicine. In one hand- 
some octavo volume of 729 pages. Cloth, $4.00; leather, $5.00. 
BARTHOLOW on Electricity as Applied to the Practice 
of Medicine and Surgery. Third edition. In one 8vo. vol- 
ume of 308pages, with 110illustrations. Cloth, $2.50. 
BROADBENT on the Pulse. In one 12mo. volume of 
317 pages. Cloth, $1.75. See Series of Clinical Manuals, 
yW on Food in Health and Disease. In one 12mo. volume 
of 590 pages. Cloth, $2. See Series of Clinical Manuals, 
sEHreiber on Massage. Translated by Mendelson. 
In one 8vo. volume of 274 pages, with 117 illustrations. 
FINLAYSON'S Clinical Manual for the Study of Medical 
Cases. For the use of Students and Practitioners of Medi- 
cine. Second edition. In one 12mo. volume of 682 pages, 
with 158 illustrations. Cloth, $2.50. 
TANNER'S Manual of Clinical Medicine and Physical 
Diagnosis. Third American from the second London edi- 
tion. In one 12mo. volume of 362 pages. Cloth, $1.50. 
STURGES' Introduction to Clinical Medicine. In one 
12mo. volume of 127 pages. Cloth, $1.25. 
DAVIS' Clinical Lectures on Various Important Diseases. 
Second edition. In one 12mo. vol. of 287 pages. Cloth, $1.75. 
TODD'S Clinical Lectures on Certain Acute Diseases. In 
one octavo volume of 320 pages. Cloth, $2.50. 
FLINT'S Essays on Conservative Medicine and Kindred 
Topics. In one 12mo. volume of 210 pages. Cloth, $1.38. 
BARLOW'S Manual of the Practice of Medicine. Cloth, 
$2.50. 
LYONS' Treatise on Fever. In one octavo volume of 354 
pages. Cloth, $2.25. 
HUDSON'S Lectures on the Study of Fever. In one octavo 
volume of 308 pages. Cloth, $2.50. 
LA ROCHE on Yellow Fever, considered in its Historical, 
Pathological, Etiological and Therapeutical Relations. In 
two large 8vo. volumes of 1468 pages. Cloth, $7.00. 
HOLLAND'S Medical Notes and Reflections. In one 
octavo volume of 493 pages. Cloth, $3.50. 
PRACTICE. 
STILLE & MAISCH'S National Dispensatory; con- 
' tabling the Natural History, Chemistry, Pharmacy, Actions 
and Uses of Medicines, including those recognized in the 
Pharmacopoeias of the United States, Great Britain and 
Germany, with numerous references to the French Codex. 
Fourth edition, with appendix. Revised to cover the 
new British Pharmacopoeia. In one magnificent imperial 
octavo volume of 1794 pages, with 311 accurate illus- 
trations. Cloth, $7.25; leather, $8.00; half Russia, open 
back, $9.00. Furnished with Patent Ready-Reference 
Thumb-letter Index for $1.00 in addition to price in any of 
above styles of binding. 
HARE'S Text-Book of Practical Therapeutics. With 
especial reference to the application of remedial measures 
to disease and their employment upon a rational basis. 
New (2d) edition. In one handsome octavo volume of 650 
pages. Cloth, $3.75; leather, $4.75. Just ready. 
BRUNTON'S Pharmacology, Therapeutics and Materia 
Medica. Third edition, in one handsome octavo volume 
of 1305 pp , with 230 illustrations. Cloth, $5.50; leather, $6.50. 
PARRISH'S Treatise on Pharmacy. Designed as a Text- 
book for the Student and as a Guide for the Physician and 
Pharmaceutist. With many Formulae and Prescriptions. 
Fifth edition, thoroughly revised, by Thomas S. Wiegand, 
Ph. G. In one handsome octavo volume of 1093 pages,with 
256 illustrations. Cloth, $5.00; leather, $6.00. 
FARQUHARSON'S Guide to Therapeutics and Materia 
Medica. Fourth American, from the fourth English edi- 
tion, specially revised by the Author, and edited, with 
additions embracing the U. S. Pharmacopoeia. In one royal 
12mo. volume of 581 pages. Cloth, $2.50. 
MAISCH'S Manual of Organic Materia Medica. Being a 
Guide to Materia Medica of the Vegetable and Animal 
Kingdoms. For the use of Students, Druggists, Pharma- 
cists and Physicians. New (Sth) edition. In one 12mo. vol- 
ume of about 550 pages, with about 275 illustrations. Shortly. 
EDES' Text-book of Therapeutics, and Materia Medica 
In one octavo of 544 pages. Cloth, $3.50; leather, $4.50. 
STILLE'S Therapeutics and Materia Medica; a System- 
atic Treatise on the Action and Uses of Medicinal Agents, 
including their Description and History. Fourth edition, 
revised and enlarged. In two large and handsome octavo 
volumes of 1936 pages. Cloth, $10.00; leather, $12.00. 
BRUCE'S Materia Medica and Therapeutics. Fifth edi- 
tion. In one 12mo. volume of 591 pages. Cloth, $1.50. See 
Students' Series of Manuals, page 1. 
HERMANN'S Experimental Pharmacology. Translated, 
with additions, by R. Meade Smith, M. D. In one 12mo. 
volume of 199 pages, with 32 illustrations. Cloth, $1.50. 
GRIFFITH'S Universal Formulary; containing the Meth- 
ods of Preparing and Administering Officinal and other 
Medicines. The whole adapted to physicians and pharma- 
ceutists. Third edition, thoroughly revised, with numerous 
additions, by John M. Maisch, Phar.D. In one large octavo 
volume of 775 pages. Cloth, $4.50; leather, $5.50. 
DIEHL'S Pharmacy. In one octavo volume of about 500 
pages, fully illustrated. Preparing. 
MATERIA MEDICA AND THERAPEUTICS. 
ABBOTT'S Bacteriology. In one 12mo. volume of 259 
pages, with 32 Illustrations. Cloth, $2. 
GlBBES' Practical Pathology and Morbid Histology. In 
one very handsome 8vo. volume of 314 pages, with 60 illus- 
trations, mostly photographic. Cloth, $2 75. 
PAYNE'S General Pathology. Designed as an introduction 
to the practice of medicine. Very handsome octavo, 524 
pages, 153 engravings and 1 colored plate. Cloth, $3.50. 
COATS' Pathology. In one handsome octavo volume of 
829 pages, with 339 illustrations. Cloth, $5.50; leather, $6.50. 
SENN'S Surgical Bacteriology. Second edition. In one 
octavo volume of 263 pages, with 13 plates, 10 of which are 
colored, and 9 wood cuts. Cloth, $2.00. 
GREEN'S Pathology and Morbid Anatomy. New (sixth) 
American, from the seventh revised and enlarged Eng- 
lish edition. In one handsome octavo volume of 540 
pages, with 167 illustrations. Cloth, $2.75. 
SCHAFER'S Essentials of Histology, Descriptive and 
Practical. New (2d) and enlarged edition. In one octavo 
volume of 311 pages, with 325 illustrations. Cloth, $3.00. 
KLEIN'S Histology. Fourth edition. In one 12mo. volume 
of 376 pages, with 194 illustrations. Cloth, $1.75. See 
Students? Series of Manuals, page 1. 
WOODHEAD'S Practical Pathology. In one 8vo. vol. of 
497 pages, with 136 colored illus. in the text. 
PEPPER'S Surgical Pathology. In one 12mo. volume of 
611 pages, with 81 illustrations. Cloth, $2.00. See 
Series of Manuals, page L 
PATHOLOGY. 
ORGANS OF RESPIRATION AND CIRCULATION. 
BROWNE'S Practical Guide to Diseases of the Throat 
and Nose, and Associated Affections of the Ear. New (3d) 
edition. In one 8vo. volume of 734 pages, with 120 illus- 
trations in color and 235 woodcuts, designed and executed 
by the author. Cloth, $6.50. 
COHEN on Throat and Nasal Passages. New edition. In 
one octavo volume of 750 pages, with 200 illus. Preparing. 
SEILER'S Handbook of Diseases of the Throat, Nose and 
Naso-Pharynx. New (4th) edition. In one 12mo. volume 
of about 400 pages, with about 100 engravings and 2 colored 
plates, containing 10 figures. Preparing. 
LEA BROTHERS & CO., PUBLISHERS, PHILADELPHIA. Condensed List of Lea Brothers & Co.'s Medical Works. 
3 
ORGANS OF RESPIRATION, etc.-continued. 
DIS. OF THE URINARY ORGANS-continued. 
GROSS' Practical Treatise on the Diseases, Injuries and 
Malformations of the Urinary Bladder, the Prostate Gland 
and the Urethra. Third edition, thoroughly revised by 
Samuel W. Gross, A. M., M. D. In one handsome 8vo. 
volume of 574 pages, with 170 illustrations. Cloth, $4.50. 
THOMPSON'S 1 lectures on Diseases of the Urinary Organs. 
Second American edition. In one octavo volume of 203 
pages, with 25 woodcuts. Cloth, $2.25. 
THOMPSON on the Pathology and Treatment of Stricture 
of the Urethra and Urinary Fistulee. From the third Eng- 
lish edition. In one octavo volume of 359 pages, with 2 
plates and 47 woodcuts. Cloth, $3.50. 
LUCAS on Diseases of the Urethra. In one 12mo. volume. 
Preparing. See Series of Clinical Manuals, page 1. 
MORRIS on Surgical Diseases of the Kidney. In one 12mo. 
volume of 554 pages, with 40 woodcuts and 6 colored 
plates. Cloth, $2.25. See Series of Clinical Manuals, page 1. 
BASHAM on Renal Diseases: a Clinical Guide to their 
Diagnosis and Treatment. In one royal 12mo. volume of 
304 pages, with illustrations. Cloth, $2.00. 
FLINT'S Manual of Auscultation and Percussion; of the 
Physical Diagnosis of Diseases of the Lungs and Heart 
and of Thoracic Aneurism. Fifth edition. Revised and 
enlarged by James C. Wilson, M. D. In one handsome 
12mo. volume of 274 pages, with 12 illustrations. Cloth, 
$1.75. 
FLINT'S Practical Treatise on the Physical Exploration of 
the Chest and the Diagnosis of Diseases Affecting the Re- 
spiratory Organs. Second and revised edition. In one hand- 
some octavo volume of 591 pages. Cloth, $4.5i). 
FLINT on Phthisis; its Morbid Anatomy, Etiology, Symp- 
tomatic Events and Complications, Fatality and Prognosis, 
Treatment and Physical Diagnosis; in a series of Clinical 
Studies. In one 8vo. volume of 442 pages. Cloth, $3.50. 
SMITH on Consumption; its Early and Remediable Stages. 
In one octavo volume of 253 pages. Cloth, $2.25. 
WILLIAMS on Pulmonary Consumption; its Nature, 
Varieties and Treatment. With an Analysis of One Thou- 
sand Cases to Exemplify its Duration. In one octavo vol- 
ume of 303 pages. Cloth, $2.50. 
FULLER on Diseases of the Lungs and Air Passages; their 
Pathology, Physical Diagnosis, Symptoms and Treatment. 
Second edition. In one 8vo. vol. of 475 pages. Cloth, $3.50. 
LA ROCHE on Pneumonia. In one octavo volume of 490 
pages. Cloth, $3.00. 
GROSS' Practical Treatise on Foreign Bodies in the Air- 
Passages. In one octavo volume of 452 pages, with 59 illus- 
trations. Cloth, $2.75. 
SLADE on Diphtheria. In one 12mo. volume. Cloth, $1.25. 
WALSHE on the Diseases of the Heart and Great Vessels. 
In one octavo volume of 416 pages. Cloth, $3.00. 
FLINT'S Practical Treatise on the Diagnosis, Pathology 
and Treatment of Diseases of the Heart. Second and 
revised edition. In one octavo vol. of 550 pages. Cloth, $4.00. 
DISEASES OF THE NERVES AND MIND. 
GRAY'S Practical Treatise on Nervous and Mental Dis- 
eases. In one handsome octavo volume of about 600 
pages, richly illustrated. In press. 
ROSS' Handbook of the Diseases of the Nervous System. 
In one octavo volume of 726 pages, with 184 illustrations. 
Cloth, $4.50; leather, $5.50. 
HAMILTON on Nervous Diseases: their Description and 
Treatment. Second edition, thoroughly revised and re- 
written. In one handsome octavo volume of 598 pages, 
with 72 illustrations. Cloth, $4.00. 
CLOUSTON on Insanity. With U. S. Laws on Custody of 
Insane, by C. F. Folsom, M. D. In one 8vo. volume of 541 
pages, with 8 plates. Cloth, $4.00. Dr. Folsom's Abstract of 
Laws for sale separately, see below. 
SAVAGE on Insanity and Allied Neuroses. In one 12mo. 
volume of 551 pages, with 18 typical illustrations. Cloth, 
$2.00. See Series of Clinical Manuals, page 1. 
TUK.E on the Influence of the Mind Over the Body in 
Health and Disease. Second edition. In one octavo vol- 
ume of 598 pages, with 72 illustrations. Cloth, $3.00. 
PLAYFAIR on Nerve Prostration and Hysteria. In one 
small octavo volume of 97 pages. Cloth, $1.00. 
FOLSOM'S Abstract of Statutes of U. S. on Custody of 
Insane. In one 8vo. volume of 108 pages. Cloth, $1.50. 
Also bound with Clouston on Insanity, above. 
JONES' Clinical Observations on Functional Nervous Dis- 
orders. In one 8vo. volume of 340 pages. Cloth, $3.25. 
ORGANS OF DIGESTION. 
ROBERTS' Collected Contributions on Diet and Digestion. 
In one 12mo. volume of 270 pages. Cloth, $1.50. 
STILLE on Cholera. Its Origin, Causation, Symptoms, 
Prevention and Treatment. In one 12mo. volume of 164 
pages, with a chart. Cloth, $1.25. 
HABERSHON on Diseases of the Alimentary Canal. 
Second American from the third and enlarged English edi- 
tion. In one octavo volume of 554 pages. Cloth, $3.50. 
CHAMBERS' Manual of Diet in Health and Disease. In 
one handsome octavo volume. Cloth, $2.75. 
P AVY'S Treatise on the Function of Digestion; its Dis- 
orders and their Treatment. From the second London edi- 
tion. In one handsome volume, small octavo. Cloth, $2.00. 
VENEREAL AND SKIN DISEASES. 
THE AMERICAN Systems of Gynaecology and Obstetrics. 
In treatises by various authors. Gynaecology edited by Mat- 
thew D. Mann, M. D., and Obstetrics edited by Barton 
C. Hirst, M. D. In four very handsome super-royal octavo 
volumes. Complete work is now ready, containing 3612 
pages, 1092 engravings and 8 plates. Per volume, cloth, 
$5.00; leather, $6.00; half Russia, $7.00. For sale by subscrip- 
tion only. 
THOMAS & MUNDE'S Practical Treatise on the Dis- 
eases of Women. New (sixth) edition rewritten and greatly 
enlarged by Dr. Paul F. Munbe. In one large and hand- 
some octavo volume of 824 pages, with 347 illustrations. 
Cloth, $5; leather, $6. 
EMMET'S Principles and Practice of Gynaecology. For 
Students and Practitioners. Third edition, revised and en- 
larged. In one large octavo vol. of 880 pp., with 150 illus. 
Cloth, $5; leather, $6.00; half Russia, raised bands, $6.50. 
DAVENPORT on Diseases of Women. A Manual of 
non-surgical Gynecology. New (2d) edition. Handsome 
12mo., 314 pages, 107 engravings. Cloth, $1.75. Just ready. 
EDIS on Diseases of Women. A Manual for Students and 
Practitioners. In one handsome 8vo. volume of 576 pages, 
with 148 Illustrations. Cloth, $3.00; leather, $4.00. 
MAY'S Manual of the Diseases of Women. Second edition, 
edited by L. S. Rau, M. D In one 12mo. volume of 360 
pages, with 31 illustrations. Cloth, $1.75. 
TAIT (Lawson) on Diseases of Women and Abdominal Sur- 
gery. In two octavo volumes. Vol. I., 554 pages, 62 engrav- 
ings and 3 plates. Cloth, $3. Vol. II. preparing. 
SUTTON on the Ovaries, Fallopian Tubes and Abdominal 
Surgery. In one 12mo. volume of 513 pages, with 119 engrav- 
ings and 5 colored plates. Cloth, $3. Just ready. 
BARNES' Clinical Exposition of the Medical and Surgical 
Diseases of Women. Third American from the third Eng- 
lish edition. In one handsome octavo volume of about 800 
pages, with about 200 illustrations. Preparing. 
DUNCAN'S Clinical Lectures on the Diseases of Women. 
In one octavo volume of 175 pages. Cloth, $1.50. 
HODGE on Diseases Peculiar to Women; including Dis- 
placements of the Uterus. Second edition, revised and 
enlarged. In one beautifully-printed octavo volume of 519 
pages, with original illustrations. Cloth, $4.50. 
ASH WELL'S Practical Treatise on the Diseases Peculiar 
to Women. One volume, 8vo., 520 pages. Cloth, $3.50. 
WEST'S Lectures on the Diseases of Women. Third 
American from the third London edition. In one octavo 
volume of 543 pages. Cloth, $3.75; leather, $4.75. 
GYNAECOLOGY. 
TAYLOR'S Clinical Atlas of Venereal and Skin Diseases. 
Including Diagnosis, Prognosis and Treatment. In eight 
folio parts, measuring 14 x 18 inches and comprising 431 
pages of text, with 85 large woodcuts and 213 figures on 58 
full-page colored plates. Price, per part, $2.50. Also, bound 
in one volume, half Russia, $27.00; half Turkey Morocco, 
$28.00. For sale by subscription only. Specimen of plates, 
by mail, 10 cents. Address the Publishers. 
HYDE on the Skin. Second edition. In one very hand- 
some octavo volume of 676 pages, with 85 illustrations, 
and two colored plates. Cloth, $4.50; leather, $5.50. 
HARDAWAY'S Manual of Skin Diseases. In one 12mo. 
volume of 474 pages. Cloth, $3. 
JAMIESON on the Skin. Third edition. In one octavo 
volume of 656 pages, with woodcut and 9 double-page 
chromo-lithographic illustrations. Cloth, $6. Just ready. 
JACK-SON'S Handbook of Diseases of the Skin. In one 
12mo. volume of 450 pages, with illustrations. Shortly. 
PYE-SMITH on Diseases of the Skin. In one octavo vol- 
ume of 450 pages, with illustrations. Preparing. 
TAYLOR on the Pathology and Treatment of Venereal 
Diseases. Being the sixth edition of Bumstead & Tay- 
lor, completely rewritten by Dr. Taylob. In one very 
handsome octavo vol., profusely illustrated. Preparing. 
BUMST EAD & TAYLOR on the Pathology and Treat- 
ment of Venereal Diseases, including the results of recent 
Investigations upon the subject. Sixth edition, rewritten 
by Dr. Taylor. See Paylor, above. 
CULVER & HAYDEN on Venereal Diseases. In one 
12mo. volume of 289 pages, with 33 illustrations. Cloth, 
$1.75. 
CORNIL on Syphilis. Translated by J. Henry C. Simes, 
M. D., and J. William White, M. D. In one very hand- 
some octavo volume of 461 pages, with 84 beautiful illustra- 
tions. Cloth, $3.75. 
HUTCHINSON on Syphilis. In one 12mo. volume of 542 
pages, with 8 chromo-lithographic plates. Cloth, $2.25. 
See Series of Clinical Manuals, page 1. 
LEE'S Lectures on Syphilis, and on Some Forms of Local 
Disease Affecting Principally the Organs of Generation. 
In one handsome octavo volume of 246 pages. Cloth, $2.25. 
HILL on Syphilis and Local Contagious Disorders. In one 
handsome 8vo. volume. Cloth, $3.25. 
FOX'S Epitome of Skin Diseases, with Formulae. For 
Students and Practitioners. Third edition, revised by T. C. 
Fox.M. R. C. S. In one 12mo.volume of 2.38 pages. Cloth, $1.25. 
WILSON'S Student's Book of Cutaneous Medicine and 
Diseases of the Skin. In one 12mo. volume of 535 pages. 
Cloth,$3.50. 
HILLIER'S Handbook of Skin Diseases, for Students and 
Practitioners. Second American edition. In one 12mo. 
volume of 358 pages, with illustrations. Cloth, $2.25. 
SMITH'S Treatise on the Diseases of Infancy and Child- 
hood. Seventh edition, thoroughly revised and rewritten. 
In one handsome octavo volume of 881 pages, with 51 illus- 
trations. Cloth, $4.50; leather, $5.50. 
OWEN on Surgical Diseases of Children. In one 12mo. 
volume of 525 pages, with 85 woodcuts and 4 chromo- 
lithographic plates. Cloth, $2.00. See Series of Clinical 
Manuals, page 1. 
WEST on Some Disorders of the Nervous System in Child- 
hood. In one volume, small 12mo. Cloth, $1.00. 
CONDIE'S Practical Treatise on Diseases of Children. 
Sixth edition. In one octavo volume of 779 pages. Cloth, 
$5.25; leather, $6.25. 
DISEASES OF CHILDREN. 
ROBERTS' Practical Treatise on Urinary and Renal Dis- 
eases, including Urinary Deposits. Fourth American from 
the fourth revised London edition. In one large octavo 
volume, of 609 pages,with 81 illustrations. Cloth, $3.50. 
PURDY on Bright's Disease and Allied Affections of the 
Kidneys. In one handsome 8vo. volume of 288 pages, with 
illustrations. Cloth, $2.00. 
DISEASES OF THE URINARY ORGANS. 
LEA BROTHERS & CO., PUBLISHERS, PHILADELPHIA. 4 
Condensed List of Lea Brothers & Co.'s Medical Works. 
THE AMERICAN System of Obstetrics, see the American 
Systems of Gynaecology and Obstetrics, above. 
PLAYFAIR'S Treatise on the Science and Practice of 
Midwifery. Fifth American from the seventh English 
edition. Edited, with additions, by Robert P. Harris, 
M. D. In one 8vo. volume of 664 pages, with 207 illustrations. 
Cloth, $4.00; leather, $5.00. 
PARVIN'S Science and Art of Obstetrics. Second edi- 
tion. In one very handsome octavo volume of 701 pages, 
with 239 illustrations. Cloth, $4.25; leather, $5.25. 
BARNES' System of Obstetric Medicine and Surgery. In 
one large octavo volume of 872 pages, with 231 illustrations. 
Cloth, $5.00; leather, $6.00. 
KING'S Manual of Obstetrics. New (5th) edition. In 
one handsome 12mo. volume of about 450 pages, with about 
150 illustrations. Shortly. 
HERMAN'S First Lines in Midwifery. In one 12mo. 
volume of 198 pages, with 80 illustrations. Cloth, $1.25. 
Just ready. See Students' Series of Manuals, page 1. 
LANDIS on the Management of Labor. Inonel2mo. vol- 
ume of 329_pages, with 28 illustrations. Cloth, $1.75. 
RAMSBOTHAM'S Principles and Practice of Obstetric 
Medicine and Surgery, in Reference to the Process of Par- 
turition. In one large imperial 8vo. volume of 640 pages, 
with 64 beautiful plates, and 43 woodcuts. Leather, $7.00. 
TANNER on the Signs and Diseases of Pregnancy. From 
the second English edition. In one 8vo. volume of 490 pages, 
with 4 colored plates and 16 woodcuts. Cloth, $4.25. 
WINCKEL on the Pathology and Treatment of Childbed. 
A Treatise for Physicians and Students. From the second 
German edition by Chadwick, with additions by the 
Author. In one octavo volume of 484 pages. Cloth, $4.00. 
MEIGS on the Nature, Signs and Treatment of Childbed 
Fever. In one 8vo. volume of 346 pages. Cloth, $2.00. 
CHURCHILL'S Essays on the Puerperal Fever, and other 
Diseases Peculiar to Women. In one 8vo. volume of 464 
pages. Cloth, $2.50. 
PARRY on Extra-Uterine Pregnancy; its Clinical History, 
Diagnosis, Prognosis and Treatment. In one handsome 
octavo volume of 272 pages. Cloth, $2.50. 
LEISHMAN'S System of Midwifery, including the Dis- 
eases of Pregnancy and the Puerperal State. Third Ameri- 
can from the third and revised English edition. In one 
large and very handsome 8vo. volume. 
OBSTETRICS. 
TREVES' Operative Surgery. In two octavo volumes 
containing 1550 pages, with 422 engravings. Cloth, $9; 
leather, $11. Just ready. 
TREVES' Manual of Surgery. In treatises by various 
authors. Edited by Frederick Treves, F. R. C. S. 
Three 12mo. volumes, containing 1866 pages, with 213 illus- 
trations. Per set, cloth, $6.00. See Students' Series of 
Manuals, page 1. 
TREVES' Student's Handbook of Surgical Operations. In 
one 12mo. volume of 508 pages, with 94 illustrations. Cloth, 
$2.50. Just ready. 
ROBERTS' Manual of Modern Surgery. In one hand- 
some octavo volume of 780 pages with 501 illustrations. 
Cloth, $4.50; leather, $5.50 
WHARTON'S Minor Surgery and Bandaging. In one 
12mo. volume of 498 pages, with 403 illustrations, many of 
which are photographic. Cloth, $3. 
STIMSON'S Practical Treatise on Fractures and Disloca- 
tions, In two octavo volumes. Volume I., Fractures, 582 
pages, 360 illus. Volume II., Dislocations, 540 pages, 163 
illus. Complete work, cloth, $5.50; leather, $7.50. Either 
volume separately, cloth, $3.00; leather, $4.00. 
STIMSON'S Manual of Operative Surgery. Second edi- 
tion. In one 12mo. volume of 503 pages, with 342 illustra- 
tions. Cloth, $2.50. 
SMITH'S (Stephen) Operative Surgery. Second and thor- 
oughly revised edition. In one very handsome octavo 
volume of 892 pages, with 1005 illustrations. Cloth, $4; 
leather, $5. 
HAMILTON'S Practical Treatise on Fractures and Dislo- 
cations. Seventh edition, thoroughly revised. In one large 
and handsome octavo volume of 998 pages, with 379 
woodcuts. Cloth, $5.50; leather, $6.50. 
GANT'S Student's Surgery. A Multum in Parvo. In one 
octavo volume of 848 pages, with 159 illus. Cloth, $3.75. 
GROSS' Practical Treatise on Impotence, Sterility and 
Allied Disorders of the Male Sexual Organs. Fourth 
edition. In one handsome 8vo. volume of 176 pages, with 
16 illustrations. Cloth, $1.50. 
THE AMERICAN SYSTEM OF DENTISTRY. In 
treatises by various authors. Edited by Wilbur F. Litch, 
M. D., D. D.S. The complete work is now ready in three 
very handsome, extra-sized octavo volumes, containing 3160 
pages, with 1873 engravings and 9 full-page plates. Per 
volume, cloth, $6.00; leather, $7.00; half Morocco, $8.00. 
For sale by subscription only. 
COLEMAN'S Dental Surgery and Pathology. Revised by 
Thomas C. Stell wagen, M. D., D. D. S. In one handsome 
volume of 412 pages, with 331 illustrations. Cloth, $3.25. 
GIBNEY'S Orthopaedic Surgery. In one 8vo. volume, pro- 
fusely illustrated. Preparing. 
YOUNG'S Orthopaedic Surgery. In one 12mo. volume of 
400 pages, with illustrations. Preparing. 
TREVES on Intestinal Obstruction. In one 12mo. volume 
of 522 pages, with 60 illustrations. Cloth, $2.00. See Series 
of Clinical Manuals, page 1. 
PICK, on Fractures and Dislocations. In one 12mo. volume 
of 530 pages, with 93 illustrations. Cloth, $2.00. See Series of 
Clinical Manuals, page 1. 
BALL on Diseases of the Rectum and Anus. In one 12mo. 
volume of 417 pages, with 54 cuts and 4 colored plates. 
Cloth, $2.25. See Series of Clinical Manuals, p. 1. 
MARSH on Diseases of the Joints. In one 12mo. volume 
of 468 pages, with 64 woodcuts and one colored plate. Cloth, 
$2.00. See Series of Clinical Manuals, page 1. 
BUTLIN on the Tongue. In one 12mo. volume of 456 
pages, with 8 colored plates and 3 woodcuts. Cloth, $3.50. 
See Series of Clinical Manuals, page 1. 
GOULD'S Surgical Diagnosis. In one 12mo. volume of 589 
pages. Cloth, $2.00. See Students' Series of Manuals, page 1. 
PIRRIE'S Principles and Practice of Surgery. In one 
8vo. volume of 784 pages, with 316 illustrations. Cloth, $3.75. 
MILLER'S Principles of Surgery. In one large octavo 
volume of 683 pages, with 240 illustrations. Cloth, $3.75. 
MILLER'S Practice of Surgery. In one large octavo vol- 
ume of 682 pages, with 364 illustrations. Cloth, $3.75. 
SURGERY-continued. 
OTOLOGY AND OPHTHALMOLOGY. 
BERRY on the Eye. A Practical Treatise for Students of 
Ophthalmology. Handsome octavo, 685 pages, 144 illustra- 
tions, of which 62 are exquisitely colored. Cloth, $7.50. 
JULER'S Ophthalmic Science and Practice. In one 8vo. 
volume of about 500 pages, with 125 woodcuts, 25 colored 
plates, and tests for color-blindness and sharpness of vision. 
English edition. Cloth, $5.50; leather, $6.50. 
NETTLESHIP'S Diseases of the Eye. Fifth and revised 
edition. With an appendix on the detection of color-blind- 
ness, by William Thomson, M. D. In one 12mo. volume 
of 504 pages, with 164 illustrations. Cloth, $2.00. 
NORRIS &: OLIVER'S Text-book of Ophthalmology. 
In one octavo volume of about 800 pages. In press. 
CARTER & FROST'S Ophthalmic Surgery. In one 
12mo. volume of 559 pages, with 91 engravings. Cloth, $2.25. 
See Series of Clinical Manuals, page 1. Color-blindness 
test, test-types and dots, and appendix of formulae. 
BURNETT on the Ear; its Anatomy, Physiology and Dis- 
eases. A practical Treatise for the use of Medical Students 
and Practitioners. Second edition. In one handsome 
octavo volume of 580 pages, with 107 illustrations. Cloth, 
$4.00; leather, $5.00. 
LAURENCE & MOON'S Handy-Book of Ophthalmic 
Surgery. For the use of Practitioners. Second edition, 
revised and enlarged. In one octavo volume of 227 pages, 
with 66 illustrations. Cloth, $2.75. 
LAWSON on Injuries to the Eye, Orbit and Eyelids; their 
Immediate and Remote Effects. In one 8vo. volume of 404 
pages, with 92 illustrations. Cloth, $3.50. 
TAYLOR'S Medical Jurisprudence. New American from 
twelfth English edition. Revised by Clark Bell, Esq. In one 
large octavo volume of 900 pages, with illustrations. Shortly. 
TAYLOR on Poisons in Relation to Medical Jurisprudence 
and Medicine. Third American from the third revised 
English edition. In one large octavo volume of 788 pages, 
with 104 illustrations. Cloth, $5.50; leather, $6.50. 
PEPPER'S Forensic Medicine. In one 12mo. volume. 
Preparing. See Students' Series of Manuals, page 1. 
MEDICAL JURISPRUDENCE. 
GROSS' System of Surgery; Pathological, Diagnostic, 
Therapeutic and Operative. Sixth edition, thoroughly re- 
vised. In two beautifully-printed imperial octavo volumes of 
2382 pages, with 1623 engravings. Strongly bound in leather, 
with raised bands, $15.00. 
HOLMES' Principles and Practice of Surgery. New Am- 
erican from fifth English edition. Edited by T. P. Pick, 
F. It. C. S. Large octavo, 997 pages, 428 engravings. Cloth, 
$6.00; leather, $7.00. 
HOLMES' System of Surgery, Theoretical and Practical. 
In Treatises by various Authors. First American from 
second English edition. Thoroughly revised, with numer- 
ous additions, by J. H. Packabd, M. D., assisted by a corps 
of thirty-three of the most eminent American Surgeons. 
In three large and very handsome imperial octavo volumes 
of 3137 pages, with 979 engravings and 13 colored plates. Per 
volume in cloth, $6.00; leather, $7.00; half Russia, raised 
bands, $7.50; For sale by subscription only. 
ERICHSEN'S Science and Art of Surgery; being a Trea- 
tise on Surgical Injuries, Diseases ana Operations. New 
American from the eighth and enlarged English edition. 
In two large and beautiful octavo volumes, containing 
2316 pages, with 984 engravings on wood. Cloth, $9.00; 
leather, $11.00. 
ASHHURST'S Principlesand Practice of Surgery. Fifth 
and revised edition. In one large octavo volume of 1144 
pages, with 642 illustrations. Cloth, $6.00; leather, $7.00. 
BRYANT'S Practice of Surgery. Fourth American from 
the fourth English edition. In one imperial 8vo. volume of 
1040 pages, with 727 engravings. Cloth, $6.50; leather, $7.50. 
DRUITT'S Principles and Practice of Modern Surgery. 
From the twelfth London edition, thoroughly revised by 
Stanley Boyd, F. R. C. S. In one handsome octavo vol- 
ume of 965 pages, with 373 illustrations. Cloth, $4.00; 
leather, $5.00. 
SURGERY. 
THE AMERICAN JOURNAL of the Medical Sciences. 
Monthly with 1888. Reduced to $4.00 per annum. 
THE MEDICAL NEWS. Every Saturday. Per annum, 
in advance, $4.00. 
The American Journal of the Medical ) Per annum, 
Sciences >■ in 
The Medical News, ) advance, $7.50. 
THE MEDICAL NEWS VISITING LIST for 1893. 
32 pages of important data and 176 pages of ruled blanks 
for all records of practice. Wallet form, pocket, pencil, rub- 
ber, and catheter scale. Issued in 4 styles: Weekly, dated 
for 30 patients; Monthly, undated, for 120 patients per 
month; Perpetual, undated, for 30 patients per week per 
year; and Perpetual, undated, for 60 patients per week per 
year. The 60-patient book consists of 256 pages of blanks. 
Price, each, $1.25. To advance-paying subscribers to above 
periodicals, 75 cents. Or. Journal, News, Year-Book of 
Treatment and Visiting List, $8.50. Thumb-letter index 25 
cents extra. 
PERIODICALS. 
MISCELLANEOUS. 
THE MEDICAL NEWS PHYSICIANS' LEDGER. 
Contains 400 pages " ledger" paper, size 9x14, conveniently 
ruled. Patent flexible back, naif Russia, $5.00. Also same 
ledger, 300 pages, $4.00. 
CARPENTER'S Prize Essay on the Use and Abuse of 
Alcoholic Liquors in Health and Disease. In one 12mo. vol. 
ume of 178nages. Cloth, 60 cents. 
HOLLAND'S Medical Notes and Reflections. In one 
octavo volume of 493 pages. Cloth $3.50. 
LEA BROTHERS & CO., PUBLISHERS, PHILADELPHIA.