IBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE N A ,1 /% 0 »>V«!I1 1VNOI1VN 3NIDI09W JO AIV11I1 IVNOI1VN 3NI3I03W JO A a V II a P 1 IVNOIIVN 3NI BRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NA1 ! m/1 \J" ,,f^/' •; o Auvxan ivnoiivn iNoiajw jo jdviim ivnoiivn jnoiqiw to jkavasu ivnoiivn jni IBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NAT NATIONAL LIBRAR BRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NA1 : /?{/ * SRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NA1 tor-; V£S^> | "'ll*«r OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NA1 IA1BRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NA1 5 /^f? 7 £ wUSrX ! N|)l UYilll IVNOIIVN 3NI3IQ3W JO UVigil IVNOIIVN 3 N I 3 I Q 3 W JO HVUM IVNOIIVN JNI AH V II9M IVNOIIVN 3NIDIQ3W JO AIVHI1 IVNOIIVN 3 N I 3 I 0 3 W JO A a V » 8 I 1 IVNOIIVN JNI ? 1 V U/i •^riVr I - / \ V 1999 61 A SYSTEM OF HUMAN ANATOMY, GENERAL AND SPECIAL. BY ERASMUS W I L S 0 N^M.D., LECTURER ON ANATOMY, LONDON. FOURTH AMERICAN FROM THE LAST LONDON EDITION. EDITED BY j PAUL B. GODDARD, A.M., M.D., PROFESSOR OF ANATOMY AND HISTOLOGY IN THE FRANKLIN MEDICAL COLLEGE OF PHILADELPHIA. \N74-U I $50 Entered, according to Act of Congress, in the year 1848, by LEA AND BLANCHARD in the clerk's office of the District Court of the United States for the Eastern District of Pennsylvania. PRINTED BY C SHERMAN. (iv) SIR BENJAMIN COLLINS BRODIE, BART., F.R.S. SERGEANT-SURGEON TO THE QUEEN, MEMBER OF THE INSTITUTE OF FRANCE, IN ADMIRATION OF THE HIGH ATTAINMENTS WHICH HAVE JUSTLY PLACED HIM IN THE FIRST RANK OF HIS PROFESSION, ffi&fs OTorft IS RESPECTFULLY INSCRIBED BY THE AUTHOR. PREFACE. The Preface to this little volume may be written in a few words. It first saw the light in the spring of 1840, and nowT, in the autumn of 1844, has reached its Third Edition. In this short period, less than five years, five thousand copies have been distributed among the Members of the Profession, many also taking their place in the libraries of Gentlemen, who, although not of the Profession, justly consider that some general knowledge of the structure of the body is an essential part of a liberal education. In the same period, a second edition of the work has appeared in America; and a translation, from the pen of Dr. Hollstein, has been completed in Berlin. Thus the volume has quickly returned for review to the hands of the Author; and he trusts that an examination of the second and present edi- tions will prove that he has not neglected this advantage. He has care- fully corrected such oversights and omissions as may have occurred in the completion of a work on so extensive a subject; many parts which seemed scantily treated, he has entirely re-written; and he has endea- voured to give as full a description of every point in Anatomy, whether important or trivial, as is consistent with the limits and objects of a Prac- tical Manual. Two features in the Anatomist's Vade Mecum appear to the Author to deserve notice: — the first relates to the labours of his professional bre- thren ; the second to the illustrations contained in the work. On the first of these heads the Author begs to remark, that he considers it a duty, as well to them as to his readers and himself, to quote all recent observations and discoveries in Anatomy which may have interest, and to give as complete an abstract of such discoveries as the scheme of the work will permit. By pursuing this plan, the Author trusts to distinguish his volume as the Record of the Profession at large, and not as the text-book merely of a particular school. And, in furtherance of his object, he has (Vil) Vlll PREFACE. to request a continuance of those communications from scientific investi- gators, which have hitherto so materially aided him. The woodcut illustrations which accompany the Anatomist's Vade Mecum have been increased with each edition. Several of the new figures are illustrative of General Anatomy, and, to insure their absolute correctness, have been drawn from the microscope by the Author himself. with the aid of the camera lucida. Figures 13, 14, 15, showing the changes which occur during the development of bone; figures 63-66, the minute anatomy of cartilage; and figure 103, the structure of the ultimate muscular fibril, are examples of such drawings. The structure exhibited in the latter figure formed the subject of a paper which was read before the Royal Society during the present year. Upper Charlotte Street, Fitzroy Square, November, 1844. PREFACE TO THE FOURTH LONDON EDITION. In preparing the "Anatomist's Vade Mecum," for the fourth time, for the Press, the Author has availed himself of the discoveries, in Ana- tomy, which have been made public since the appearance of the preceding edition ; and he takes the opportunity, now afforded him, of acknowledg- ing his obligation to the several investigators whose researches he has quoted. To one gentleman, namely, to Mr. Paget of St. Bartholomew's Hospital, he feels particularly indebted for the assistance which he has derived from the excellent " Reports, on the chief results obtained by the use of the Microscope in the study of Human Anatomy and Physiology," published in the British and Foreign Medical Review. In the present edition of this volume, the Wood-cut Illustrations have been augmented to two hundred ; and the Author, begs to observe that, with very few exceptions, which have been duly acknowledged, the whole of the subjects are original; the drawings having been executed by Mr. Bagg from dissections prepared expressly for the work, or from drawings made by himself. The chief of the illustrations of General Anatomy were drawn from the microscope with the camera lucida, in order to ensure absolute correctness. Upper Charlotte Street, Fitzroy Square, March 1, 1847. (ix) PREFACE TO THE FOURTH AMERICAN EDITION. The Editor, in presenting this new edition of Mr. Wilson's standard work on Anatomy, has found but little to add, the author having so com pletely revised and brought up his last edition ; while he has incorporated in the text many of the Editor's notes to former editions. A small increase in the size of the page has enabled the Publishers to take in the additional matter, while diminishing slightly the number of pages. The Editor has added some new matter and a large number of new cuts— among others an important series on the nerves—he has rewritten his in- troductory chapter on Histology; and he has taken every care to ensure, throuo-hout, perfect correctness in the text. He thus hopes that the work will continue to hold the high character which its merits have acquired in this country, and to maintain its position as a standard Text Book for the student, which it has assumed in so many of our Colleges. The London edition is still known by the Author's original title of " Vade Mecum ;" but the publishers consider themselves sustained in the change they have made, by the fulness and completeness of the work, which amply warrant for it the title of "A System of Human Anatomy." P. B. G. Philadelphia, July, 1848. (xi) CONTENTS. CHAPTER I. histology. Page Definition..........................33 Chemistry of the tissues..............33 Nitrogenized substances..............35 Non-nitrogenized substances...........3G Of the tissues......................37 Tabular view of the tissues...........37 Description of the tissues.............38 Page Physical properties..................39 Vital properties.................^ ... 40 Development of tissues...............40 Development of cells.................41 Multiplication of cells................41 Transformation of cells...............42 CHAPTER II. OSTEOLOGY. Page Definition................. .-.*......43 Chemical composition of bone.........43 Division into classes.................43 Structure of bone...................44 Development of bone................46 Period of ossification................48 The skeleton.......................49 Vertebral column...................50 Cervical vertebrae..................50 Dorsal vertebra...................53 Lumbar vertebra..................53 General considerations.............54 Development.....................55 Attachment of muscles.............56 Sacrum.........................56 Coccyx..........................58 The skull........................58 Bones of the cranium................58 Occipital bone....................59 2 Page Parietal bone.....................61 Frontal bone.....................62 Temporal bone...................64 Sphenoid bone....................69 Ethmoid bone....................72 Bones of the face...................74 Nasal..........................74 Superior maxillary................74 Lachrymal bone..................77 Malar bone......................77 Palate bone......................78 Inferior turbinated bone............80 Vomer..........................80 Inferior maxillary.................81 Table of developments, articulations, &c. 83 Sutures...........................83 Regions of the skull.................84 Base of the skull..................86 Face...........................89 (xiii) XIV CONTENTS. Page Orbits........................... 90 Nasal fossa?....................... 90 Teeth............................ 92 Structure....................... 93 Development.................... 95 Growth........................ 97 Eruption....................... 98 Succession...................... 99 Os hyoides........................ 99 Thorax and upper extremity.........100 Sternum........................ 100 Ribs...........................101 Costal cartilages.................102 Clavicle........................103 Scapula........................103 Humerus.......................105 Ulna..........................106 Radius.........................107 Page Carpal bones....................109 Metacarpal bones................. H2 Phalanges......................113 Pelvis and lower extremity...........114 Os innominatum.................114 Ilium..........................H4 Ischium........................115 Os pubis.......................116 Pelvis — Its Divisions—Axes—Dia- meters .................117, 118 Femur.........................119 Patella.........................121 Tibia..........................121 Fibula.........................122 Tarsal bones....................124 Metatarsal bones................. 127 Phalanges...................... 128 Sesamoid bones..................129 CHAPTER III. THE LIGAMENTS. Page Forms of articulation...............130 Synarthrosis.................... 130 Amphi-arthrosis.................130 Diarthrosis...................... 130 Movements of joints................131 Gliding........................131 Angular movement............... 131 Circumduction..................131 Rotation.......................132 General anatomy of articular structures 132 Cartilage.......................132 True cartilage...................132 Reticular cartilage................132 Fibrous cartilage.................134 Fibrous tissue...................134 Ligament......................135 Tendon........................135 Adipose tissue...................136 Synovial membrane..............136 Ligaments of the trunk—arrange- ment ........................137 Articulation of the vertebral column ... 137 Of the atlas with the occipital bone.. 140 Of the axis with the occipital bone .. 141 Of the atlas with the axis.........141 Of the lower jaw................142 Of the ribs of the vertebra?.........144 Page Of the ribs with the sternum, and with each other ................... 145 Of the sternum..................146 Of the vertebral column, with the pelvis......................146 Of the pelvis....................146 Ligaments of the upper extremitt 149 Sterno-clavicular articulation.........149 Scapuloclavicular articulation........151 Ligaments of the scapula............151 Shoulder joint.....................152 Elbow joint.....,................. 152 Radio-ulnar articulation.............153 Wrist joint.......................155 Articulations of the carpal bones......156 Carpo-metacarpal articulation........156 Metacarpophalangeal articulation.....157 Articulation of the phalanges.........158 Ligaments of the lower extremity 158 Hip joint.........................158 Knee joint........................ 159 Articulation between the tibia and fibula 163 Ankle joint.......................164 Articulation of the tarsal bones.......165 Tarso-metatarsal articulation.........167 Metatarso-phalangeal articulation...... 167 Articulation of the phalanges.........168 CONTENTS. XV CHAPTER IV. THE MUSCLES. Page General anatomy of muscle...........168 Nomenclature — Structure..........169 Muscles of the head and face.....173 Arrangement into groups............173 Cranial group—Dissection...........174 Occipito-frontalis.................174 Orbital group—Dissection...........175 Orbicularis palpebrarum...........175 Corrugator supercilii..............175 Tensor tarsi—Actions............ 176 Ocular group—Dissection ..........176 Levator palpebral—Rectus superior .. 177 Rectus inferior — Rectus internus — Rectus externus...............177 Obliquus superior................178 Obliquus inferior—Actions.........178 Nasal group.......................179 Pyramidalis nasi—Compressor nasi.. 179 Dilatator naris—Actions........... 179 Superior labial group...............180 Orbicularis oris—Levator labii superi- ors alaeque nasi.............180 Levator labii superioris proprius.....180 Levator anguli oris—Zygomatici.... 180 Depressor labii superioris alaeque nasi 181 Actions........................181 Inferior labial group—Dissection...... 181 Depressor labii inferioris...........181 Depressor anguli oris—Levator labii inferioris...............181, 182 Actions........................182 Maxillary group................... 182 Masseter—Temporal muscle.......182 Buccinator—External pterygoid mus- cle ........................183 Internal pterygoid muscle..........184 Actions........................184 Auricular group—Dissection.........184 Attollens aurem................. 184 Attrahens aurem................185 Retrahens aurem—Actions........185 Muscles of the neck.............185 A rrangement into groups............185 Superficial group—Dissection........186 Platysma myoides................ 186 Sterno-cleido-mastoideus...........186 Actions........................ 187 Depressors of the os hyoides and larynx 187 Dissection......................188 Sterno-hyoideus — Sterno-thyroideus. 188 Thyro-hyoideus—Omo-hyoideus .... 188 Actions........................ 189 Elevators of the os hyoides..........189 Dissection......................189 Digastricus.....................189 Page Stylo-hyoideus — mylo-hyoideus 189, 190 Genio-hyoideus—Genio-hyo-glossus— Actions....................190 Muscles of the tongue...............191 Hyo-glossus—Lingualis...........191 Stylo-glossus....................192 Palato-glossus—Actions........... 192 Muscles of the pharynx—Dissection. .. 192 Constrictor inferior...............192 Constrictor medius—Constrictor supe- rior .......................193 Stylo - pharyngeus — Palato - pharyn- geus—Actions..........193, 194 Muscles of the soft palate—Dissection. . 194 Levator palati—Tensor palati. . .194, 195 Azygos uvulae—Palato-glossus......195 Palato-pharyngeuF —Acti i.i: . . .. 195, 196 Praevertebral muscles—Dissection......196 Rectus anticus major—Rectus ...■ icus minor.....................196 Scalenus anticus.................196 Scalenus posticus—Longus colli.... 197 Actions.......................198 Muscles of the larynx.............. 198 Muscles of the trunk............ 198 Muscles of the back—Arrangement.. .. 198 First layer—Dissection..........199 Trapezius.................... 199 Latissimus dorsi...............199 Second layer—Dissection..........,201 Levator anguli scapulae..........' 201 Rhomboideus minor et major.....201 Third layer—Dissection...........201 Serratus posticus superior et infe- rior....................201,202 Splenius capitis et colli .........f 02 Fourth layer—Dissection..........v-QZ Sacro-luinbalis—Longissimus dorsi v )3 Spinalis dorsi.................i 1 Cervicalis ascendens—Transversa- •• lis colli....................2 '4 Trachelo-mastoideus — Complexus i 4 Fifth layer—Dissection............205 Semi-spinalis dorsi et colli.......205 Rectus posticus, major et minor. . . 205 Rectus lateralis—Obliquus inferior et superior..................205 Sixth layer—Dissection...........205 Multifidus spinae—Levatores cos- tarum....................206 Supra-spinalis—Inter-spinales .... 206 Inter-transversales.............206 Actions......................207 Table of origins and insertions of the muscles of the back...... 208, 209 XVI CONTENTS. Page Muscles of the thorax...............210 Intercostales externi et interni......210 Triangularis sterni—Actions.......211 Muscles of the abdomen.............211 Dissection......................211 Obliquus externus...............212 Obliquus internus................214 Cremaster......................214 Transversalis...................215 Rectus........................216 Pyramidalis—Quadratus lumborum . 216 Psoas parvus...................216 Diaphragm.....................217 Actions........................218 Muscles of the perineum.............219 Dissection......................219 Acceleratores urinae.............. 220 Erector penis...................220 Compressor urethra?..............220 Transversus perinei..............221 Sphincter ani externus et internus. .. 222 Levator ani—Coccygeus..........222 Muscles of the female perineum .... 222 Muscles of the upper extremity. . 223 Anterior thoracic region.............224 Dissection...........•............225 Pectoralis major et minor..........225 Subclavius—Actions.............226 Lateral thoracic region.............226 Serratus magnus—Actions........226 Anterior scapular region............226 Subscapularis...................226 Actions.,.......................227 Posterior scapular region............227 Supra-spinatus—Infra-spinatus.....227 Teres minor—Teres major.....227, 228 Actions........................228 Acromial region...................228 Deltoid—Actions................228 Anterior humeral region—Dissection .. 229 Coraco-brachialis—Biceps . •........229 Brachialis anticus—Actions.......230 Posterior humeral region............230 Triceps—Actions................231 Anterior brachial region.............231 Superficial layer—Dissection.......231 Pronator radii teres............231 Flexor carpi radialis............232 Palmaris longus...............232 Flexor sublimis digitorum.......232 Flexor carpi ulnaris............233 Deep layer—Dissection...........233 Flexor profundus digitorum .....233 Flexor longus pollicis...........233 Pronator quadratus—Actions .... 234 Posterior brachial region............234 Superficial layer—Dissection____234 Supinator longus..............234 Extensor carpi radialis longior . .. 235 Extensor carpi radialis brevior.. .. 235 Extensor communis digitorum.. .. 235 Extensor minimi digiti..........236 Extensor carpi ulnaris—Anconeus 236 Deep layer—Dissection.......236, 237 Supinator brevis...............237 Extensor ossis metacarpi pollicis. . 237 Extensor primi internodii pollicis.. 237 Extensor secundi internodii pollicis 237 Extensor indicis—Actions.......238 Muscles of the hand................238 Radial region—Dissection.........238 Ulnar region—Dissection......239, 240 Palmar region...................240 Actions........................242 Muscles of the lower extremity. 242 Gluteal region—Dissection..........243 Gluteus maximus et medius.......244 Gluteus minimus................245 Pyriformis......................245 Gemellus superior—Obturator inter- nus .......................245 Gemellus inferior—Obturator exter- nus .......................246 Quadratus femoris—Actions.......246 Anterior femoral region—Dissection ... 246 Tensor vagina? femoris—Sartorius... 247 Rectus—Vastus externus..........248 Vastus internus—Crureus—Actions. 248 Internal femoral region—Dissection . . . 249 Iliacus internus.................249 Psoas magnus—Pectineus — Adduc- tor longus..............249, 250 Adductor brevis—Adductor magnus —Gracilis.............250, 251 Actions........................251 Posterior femoral region—Dissection . . 251 Biceps femoris...................251 Semi-tendinosus—Semi-membranosus —Actions..............251, 252 Anterior tibial region...............253 Dissection......................253 Tibialis anticus..................253 Extensor longus digitorum.........253 Peroneus tertius—Extensor proprius pollicis....................254 Actions........................254 Posterior tibial region...............254 Superficial group—Dissection......254 Gastrocnemius................255 Plantaris—Soleus—Actions.....255 Deep layer—Dissection...........255 Popliteus—Flexor longus pollicis. 256 Flexor longus digitorum........256 Tibialis posticus..............257 Actions......................257 Fibular region—Dissection...........257 Peroneus longus—Peroneus brevis 258 Actions................... 258 Foot—Dorsal region...............258 Plantar region................. 259 First layer—Dissection.........259 Second layer—Dissection.......261 Third layer—Dissection.........261 Fourth layer—Actions..........262 CONTENTS. XV11 CHAPTER V. THE FASCIA. Page General anatomy...................263 FASCI2B OF THE HEAD AND NECK......264 Temporal fascia..................264 Cervical fascia...................264 Fascia of the trunk.............265 Thoracic fascia..................265 Abdominal fascia................266 Fascia transversalis..............266 Oblique inguinal hernia............. 266 Congenital hernia..................267 Encysted hernia...................267 Direct inguinal hernia...............268 Page Fascia iliaca......................268 Fascia pelvica.....................268 Obturator fascia....................269 Superficial perineal fascia............269 Deep perineal fascia................269 Fasciae of the upper extremity .. . 271 Fascije of the lower extremity. .. 272 Fascia lata........................272 Femoral hernia....................273 Fascia of the leg...................274 Plantar fascia.....................274 CHAPTER VI THE ARTERIES. Page General anatomy of arteries..........275 Inosculations—Structure........276, 277 Aorta............................278 Table of branches................281 Coronary arteries..................281 Arteria innominata.................281 Common carotid arteries.............282 External carotid artery..............283 Table of branches................284 Superior thyroid artery............284 Lingual artery...................285 Facial artery....................285 Mastoid artery...................287 Occipital artery..................287 Posterior auricular artery..........287 Ascending pharyngeal artery.......287 Parotidean arteries...............287 Transverse facial artery............287 Temporal artery.................288 Internal maxillary................288 Internal carotid artery...............291 Ophthalmic artery................292 Anterior cerebral artery...........293 Middle cerebral artery.............294 Subclavian artery..................294 Table of branches................296 Vertebral artery..................296 Basilar artery....................296 Circle of Willis..................297 Thyroid axis....................298 Inferior thyroid artery.............298 Supra-scapular artery.............298 Posterior scapular................299 Superficial cervicis..............299 2* Page Profundis cervicis................299 Superior intercostal artery—Internal mammary ; branches.........299 Axillary artery.....................300 Table of branches................301 Brachial artery....................303 Radial artery......................304 Ulnar artery.......................306 Thoracic aorta ; branches............308 Abdominal aorta ; branches..........309 Phrenic arteries..................309 Cceliac axis.....................310 Gastric artery...................310 Hepatic artery...................310 Splenic artery...................311 Superior mesenteric artery.........312 Spermatic arteries................314 Inferior mesenteric artery..........315 Renal arteries...................315 Lumbar arteries.................315 Sacra media.....................316 Common iliac arteries...............316 Internal iliac artery.................317 Ischiatic........................318 Internal pudic artery..............318 External iliac artery................321 Femoral artery....................323 Popliteal artery....................326 Anterior tibial artery................328 Dorsalis pedis artery................329 Posterior tibial artery...............330 Peroneal artery..................331 Plantar arteries....................332 Pulmonary artery..................334 XV111 CONTENTS. CHAPTER VII. THE VEINS. Paire General anatomy...................334 Veins of the head and neck..........336 Veins of the diploe.................337 Cerebral and cerebellar veins...... .. . 338 Sinuses of the dura mater...........338 Veins of the neck..................341 Veins of the upper extremity.........342 Veins of the lower extremity.........344 Veins of the trunk.................344 Page Venae innominatae................ 345 Superior vena cava...............345 Iliac veins......................345 Inferior vena cava................346 Azygos veins....................348 Vertebral and spinal veins.........348 Cardiac veins....................349 Portal system.............."......349 Pulmonary veins.................351 CHAPTER VIII THE LYMPHATICS. Page General anatomy...................351 Lymphatics of the head and neck.....353 Lymphatics of the upper extremity .... 354 Lymphatics of the lower extremity .... 355 Ductus lymphaticus dexter Lymphatics of the trunk............356 | Page Lymphatics of the viscera............357 Lacteals........................358 Thoracic duct.....................359 ......360 CHAPTER IX. THE NERVOUS SYSTEM. Page General anatomy...................361 The brain.........................367 Membranes of the encephalon........368 Dura mater.....................369 Arachnoid membrane.............370 Pia mater.......................371 Cerebrum.........................372 Lateral ventricles.................373 Fifth ventricle...................376 Fornix.........................378 Thalami optici..................378 Third ventricle..................378 Corpora quadrigemina.............379 Pineal gland....................379 Fourth ventricle.................380 Lining membrane of the ventricle... 380 Cerebellum.......................381 Base of the brain..................382 Page Medulla oblongata.................385 Diverging fibres....................386 Converging fibres; commissures......388 Spinal cord.......................389 Cranial nerves.....................392 Spinal nerves.....................409 Cervical plexus..................411 Brachial plexus..................414 Dorsal nerves....................420 Lumbar nerves..................422 Sacral nerves....................426 Sympathetic system................433 Cranial ganglia..................433 Cervical ganglia.................437 Thoracic ganglia.................440 Lumbar ganglia..................441 Sacral ganglia...................442 CONTENTS. XIX CHAPTER X. ORGANS OF SENSE. CHAPTER XI. THE VISCEBA. Page Thorax.........................475 Heart............................475 Structure of the heart...............482 Organs of respiration and voice.......485 Larynx—Cartilages..............485 Ligaments ....................486 Muscles......................488 Trachea and Bronchi.............491 Thyroid gland...................492 Lungs.........................492 Pleurae.........................495 Mediastinum....................496 Abdomen—Regions................496 Peritoneum.....................497 Alimentary canal.................501 Lips—Cheeks—Gums—Palate.....502 Tonsils —Fauces................503 Salivary glands..................503 Pharynx.......................504 Stomach.......................505 Small intestine..................506 Large intestine..................507 Structure of the intestinal canal .... 509 Page A bdomen—continued. Liver..........................515 Gall-bladder....................525 Pancreas.......................526 Spleen.........................526 Supra-renal capsules..............527 Kidneys........................528 Pelvis..........................532 Bladder........................532 Prostate gland...................534 Vesiculae seminales...............535 Male organs of generation.......536 Penis .........................536 Urethra........................537 Testes................... .....541 Female pelvis...................544 Bladder—Urethra................544 Vagina........................545 Uterus.........................546 Fallopian tubes..................549 Ovaries........................549 External organs of generation......550 Mammary glands................551 CHAPTER XII. rage Organ of hearing—continued. Tympanum.....................458 Ossiculi auditus..................458 Muscles of the tympanum.........459 Internal ear.....................461 Vestibule.......................462 Semicircular canals—Cochlea......463 Membranous labyrinth............465 Organ of taste—Tongue............467 Organ of touch—Skin..............468 Appendages of the skin—Nails.......472 Hairs—Sebiparous glands..........474 Sudoriparous glands..............474 ER XI. [SCEBA. Page A bdomen—continued. Liver..........................515 Gall-bladder....................525 Pancreas.......................526 Spleen.........................526 Supra-renal capsules..............527 Kidneys........................528 Pelvis..........................532 Bladder........................532 Prostate gland...................534 Vesiculae seminales...............535 Male organs of generation.......536 Penis .........................536 Urethra........................537 Testes................... .....541 Female pelvis...................544 Bladder—Urethra................544 Vagina........................545 Uterus.........................546 Fallopian tubes..................549 Ovaries........................549 External organs of generation......550 Mammary glands................551 ER XII. Page Nose............................442 N asal fossae.......................444 Eyeball..........................445 Sclerotic coat and cornea..........445 Choroid coat; ciliary ligament; iris . 447 Retina; zonula ciliaris............449 Humours.......................451 Physiological observations.........452 Appendages of the eye..............453 Lachrymal apparatus...............455 Organ of hearing..................456 External ear ; pinna..............456 Meatus auditorius................457 ANATOMY OF Page Osseous and ligamentous system......553 Muscular system...................553 Vascular system...................553 Foetal circulation...................553 Nervous system....................555 Organs of Sense—Eye—Ear—Nose. .. 555 Thyroid glmd.....................556 Thymus gland.....................556 THE F02TUS. Page Fcetal lungs.......................558 Foetal heart.......................559 Viscera of the abdomen.............559 Omphalo-mesenteric vessels........559 Foetal liver.....................560 Kidneys and supra-renal capsules .. . 560 Viscera of the pelvis................560 Testes—Descent.................560 TABLE OF ILLUSTRATIONS. Figs. Page 1. Vegetable nucleated cells........ 37 2. Growth of cells................ 41 3. Reproduction of cells........... 41 4. Implantation of cells............ 41 5. Transformation of cells......... 42 ' / Changes in formative cells of ' i an animal............... 42 9. Id. of a vegetable....... 42 10. Formation of fibres............. 42 11. Minute structure of bone........ 44 12. Id. id. id.......... 45 13. Development of bone........... 47 14. Id. id................ 47 15. Id. id................ 47 16. Cervical vertebra.............. 51 17. Atlas........................ 51 18. Axis........................ 52 19. Dorsal vertebra................ 53 20. Lumbar vertebra.............. 53 21. Sacrum...................... 57 22. Occipital bone—External surface . 59 23. Occipital bone—Internal surface .. 60 24. Parietal bone—External surface . . 61 25. Parietal bone—Internal surface... 62 26. Frontal bone—External surface .. 63 27. Frontal bone—Internal surface... 63 28. Temporal bone—External surface. 64 29. Temporal bone—Internal surface . 66 30. Meatus auditorius externus and in- ternus, and tympanic bone..... 66 31. Sphenoid bone—Superior surface . 69 32. Sphenoid bone — Antero-inferior surface..................... 70 33. Ethmoid bone................. 73 34. Superior maxillary bone........ 74 35. Lachrymal bone............... 77 36. Palate bone—Internal surface .... 78 37. Palate bone—External surface ... 79 38. Inferior maxillary bone......... 82 39. Skull, anterior view............ 85 40. Base of the skull; internal view .. 85 41. Base of the skull; external view. . 87 42. Nasal fossa with the turbinated bones...................... 91 43. Permanent teeth............... 92 44. Temporary teeth............. 93 45 Section of molar tooth.......... 94 Figs. Page 46. Capsule of temporary incisor..... 97 47. Temporary tooth with capsule of permanent.................. 98 48. Os hyoides................... 99 49. Thorax......................101 50. Scapula...................... 104 51. Humerus....................106 52. Ulna and radius...............108 53. Bones of the carpus; posterior view 109 54. Hand; anterior view........... Ill 55. Os innominatum..............114 56. Female pelvis; anterior view .... 117 57. Femur; anterior view.......... 119 58. Femur; posterior view.........120 59. Tibia and fibula; anterior view.. . 122 60. Tibia and fibula ; posterior view. . 123 61. Foot; dorsal surface...........125 62. Foot; plantar surface.......... 128 63. Articular cartilage.............132 64. Id. id................132 65. Id. id................133 66. Reticular cartilage.............133 67. Fibrous cartilage..............133 68. White fibrous tissue............134 69. Yellow fibrous tissue...........135 70. Adipose tissue................ 136 71. Epithelium of serous membrane. . 137 72. Ligaments of the vertebrae and ribs ; anterior view................138 73. Posterior common ligament...... 138 74. Ligamenta subflava............139 75. Ligaments of the atlas, axis, and occipital bone...............140 76. Id.; posterior view.............140 77. Id.; internal view.............141 78. Id. ; internal view.............142 79. Ligaments of the lower jaw ; ex- ternal view.................143 80. Id.; internal view............. 143 81. Id; section...................144 82. Ligaments of the vertebral column and ribs....................145 83. Ligaments of the pelvis and hip joint 148 84. Id. id. id.... 148 85. Ligaments of the sternal end of the clavicle and costal cartilages.. .. 150 86. Ligaments of the scapula and shoulder joint...............151 (xxi) XX11 TABLE OF ILLUSTRATIONS. Figs. Page 87. Ligaments of the elbow ; internal view.......................153 88. Id.; external view.............153 89. Radio-ulnar articulation......... 154 90. Ligaments of the wrist and hand. 155 91. Synovial membranes of the wrist. . 157 92. Knee joint; anterior view.......160 93. Id.; posterior view............ 161 94. Knee joint; internal view.......161 95. Id. ; reflexions of the synovial membrane..................162 96. Ankle joint; internal view...... 164 97. Id.; external view.............164 98. Id.; posterior view. ........... 166 99. Ligaments of the sole of the foot.. 167 100. Minute structure of muscle...... 170 101. Id. id..................170 102. Id. id.................. 171 103. Id. id.................. 171 104. Id. id.................. 172 105. Muscles of the face.............174 106. Tensor tarsi.................. 176 107. Muscles of the orbit............176 108. Pterygoid muscles............. 184 109. Muscles of the neck; superficial and deep...................186 110. Muscles of the tongue.......... 191 111. Muscles of the pharynx.........194 112. Muscles of the soft palate....... 195 113. Muscles of the praevertebral region 197 114. Muscles of the back; 1st, 2d, and 3d layer....................200 115. Muscles of the back ; deep layer.. 203 116. Muscles of the anterior aspect of the trunk...................213 117. Muscles of the lateral aspect of the trunk.....................215 118. Diaphragm............,.'......218 119. Muscles of the perineum........221 120. Muscles of the anterior humeral re- gion.......................229 121. Triceps extensor cubiti..........230 122. Superficial layer of muscles of the anterior aspect of the fore-arm. . 231 123. Deep layer of muscles of the ante- rior aspect of the fore-arm.....234 124. Superficial layer of muscles; poste- rior aspect of the fore-arm......235 125. Deep layer; posterior aspect of the fore-arm....................237 126. Muscles of the hand, anterior aspect 239 127. Palmar interossei..............241 128. Dorsal interossei...............241 129. Muscles of the gluteal region, deep layer......................244 130. Muscles of the anterior and internal femoral region..............247 131. Muscles of the gluteal and posterior femoral region...............252 132. Muscles of the anterior tibial re- gion".......................253 133. Muscles of the posterior tibial re- gion .......................255 Figs. 134 135 136 137. 138. 139. 140. 141. 142. 143. 144. 145. 146. 147. 148. 149. 150. 151. 152. 153. 154. 155. 156. 157. 158. 159. 160. 161. 162. 163. 164. 165. 16G. 167. 168. 169. 170. 171. 172. 173. 174. 175. 176. 177. 178. Page Muscles of the posterior tibial region, deep layer..................256 Dorsal interossii...............259 Muscles of the sole of the foot; 1st layer......................259 Muscles of the sole of the foot; 2d layer......................260 Deep-seated muscles............261 Plantar interossii..............263 Section of the neck, showing the distribution of the deep cervical fascia......................265 Transverse section of the pelvis, showing the distribution of the fasciae.....................269 Deep perineal fascia ...........270 Distribution of the deep perineal fascia ; side view.............270 Distribution of the fasciae at the femoral arch................273 The great vessels of the chest .... 278 Branches of the external carotid artery......................284 External carotid...............289 Branches of the subclavian artery. 296 The circle of Willis............298 Axillary and brachial arteries .... 301 Arteries of the fore-arm—Radial and ulnar...................304 Branches of the abdominal aorta. . 310 Coeliac axis with its branches.... 312 The superior mesenteric artery ... 313 The inferior mesenteric artery.... 314 The internal iliac artery with its branches...................317 The arteries of the perineum.....319 The femoral artery with its branches 323 The anterior tibial artery........328 Posterior tibial and peroneal artery 330 Arteries of the sole of the foot.... 332 Sinuses of the dura mater.......339 Sinuses of the base of the skull. .. 340 Veins and nerves of the bend of the elbow......................342 Veins of the trunk and neck.....346 The portal vein...............350 The thoracic duct.............360 Minute structure of nerve.......363 The centrum ovale majus and cor- pus callosum................373 The lateral ventricles of the cere- brum ......................374 Longitudinal section of the brain.. 377 Base of the brain..............384 Distribution of the fibres of the brain 387 Sections of the spinal marrow .... 391 Sections of the spinal cord.......392 The olfactory nerve............393 Origin of the optic and fourth nerves 394 The isthmus encephali, showing the thalamus opticus, corpora quadri- gemina, pons Varolii, and medulla oblongata...................394 TABLE OF ILLUSTRATIONS. xxiii Pigs. Page 179. Third, 4th, and 5th pair of nerves 396 180. Trifacial or fifth nerve..........397 181. Portio mollis of 7th pair........401 182. Facial and cervical nerves......403 183. Eighth pair of nerves...........406 184. Hypoglossal or ninth nerve......408 185. Part of the cervical portion of the spinal cord.................410 186. Axillary plexus and nerves of the upper extremity.............414 187. Nerves of front of fore-arm.......417 18H. Nerves of back of fore-arm.......418 189. Lumbar and sacral plexus, with the nerves of the lower extremity. . . 422 190. Anterior crural nerve...........424 191. Branches of ischiatic plexus......427 192. id. popliteal nerve......430 193. Posterior tibial nerve...........430 194. Nerves of sole of foot...........431 195. Anterior tibial nerve...........432 196. The cranial ganglia of the sympa- thetic nerve.................434 197. (irent sympathetic..............439 198. Fibro-cartilages of the nose......443 199. Longitudinal section of the globe of the eye...................446 200. Venae vorticosse of choroid coat . . . 448 201. A transverse section of the globe of the eye....................449 202. Another transverse section of the globe of the eye..............449 203. Auxiliary parts of eye...........45J 204. A diagram of the ear...........458 205. Anatomy of the cochlea.........464 206. Osseous and membranous labyrinth of the ear..................464 207. Papillae of tongue..............467 208. Anatomy of the skin...........469 209. Development of epidermis.......470 210. Anatomy of the skin...........473 211. The heart....................476 212. Anatomy of the heart, right side .. 478 Figs. .Page 213. Anatomy of the heart, left side ... 482 214. Ligaments of the larynx........487 215. Muscles of the larynx..........488 216. Id. id.................489 217. Anatomy of the lungs and heart. . 493 218. Viscera of abdomen............497 219. The peritoneum...............498 220. The pharynx..................505 221. Anatomy of the stomach and duo- denum.....................506 222. Caecum and appendix.......... . 508 223. Section of anus................510 224. Peyer's glands...............513 225. Section" of parietes of anus.......514 226. The liver; its upper surface......516 227. The liver; its under surface.....517 228. Lobules of the liver............519 229. Id. id.................519 230. Section of superficial lobules.....520 231. Id. id.................521 232. Section of the kidney............529 233. Plan of the renal circulation.....531 234. A side view of the viscera of the male pelvis..................533 235. A posterior view of the bladder and vesiculae seminales............535 236. Anatomy of the urethra........538 237. Prostatic urethra..............539 238. Transverse section of the testicle. . 541 239. Anatomy of the testis ..........543 240. Injected testis................. 544 241. A side view of the viscera of the female pelvis................545 242. Uterus and Fallopian tubes......546 213. Section of uterus..............547 244. Female external organs of genera- tion .......................550 245. Foetal circulation..............554 246. Section of the thymus gland......557 247. Ducts of the thymus gland ...... 557 248-9. Descent of the testis in the foetus 561 A SYSTEM OF HUMAN ANATOMY. CHAPTER I. INTRODUCTORY. B'J THE EDITOR. .' • . Anatomy (derived from avurepvsiv, to dissect) is the science which teaches the structure and relation of the different parts of an organized body. Organized bodies are divided into animal and vegetable ; hence we have animal and vegetable anatomy, the latter being closely allied to botany. An organized body consists of an assemblage of parts called organs, which have a mutual relation to, and dependence upon each other ; each doing its part to sustain the organism which they compose. The descrip- tion of the form, colour and position of these organs is the province of special anatomy; whilst their relations to each other, and the knowledge of the number and arrangement of organs in particular parts, constitutes regional or topographical anatomy, which, when taught with reference to surgical operations, is usually designated by the title of surgical anatomy. When these organs are carefully examined, they are found to consist of a number of different structures which serve to build up and constitute them. These are called tissues, and are either general, existing in all the organs, or special and peculiar, and found only in certain of them, giving them their appropriate characters. The knowledge of tissues, their form, colours, constituents, origin and uses, constitutes histology; which, com- mencing with Bichat in 1790, has now attained such an extent and im- portance as to constitute almost a new science, and to correct and bring nearer to perfection the hypotheses of its sister science, physiology. An animal body or organism consists of solids, which differ in density and hardness, in consequence of being more or less mingled with and di- luted by the fluids which permeate them. By the agency of chemistry we may separate both solids and fluids into proximate and ultimate elements, and hope by this means to obtain a more intimate acquaintance with their structure and use; but if this is done with the masses as is usual in chemical analyses, and not upon the tissues separated from each other by the aid of the microscope, it will confer upon us about as much real and useful information, as the analysis which a scientific but witty English chemist once made of a whole mouse. The principal ultimate elements of an animal body obtained by the pro- cesses of chemical analysis are— Oxygen, hydrogen, carbon, and nitrogen, which form almost the whole bulk of the fluids and soft solids ; but to these must be added a number c (33) 34 HISTOLOGY. of others, which, although they exist in smaller proportions, still form im- portant constituents of peculiar tissues. Thus we find— Lime, or its base, calcium, combined with the carbonic or phosphoric acids, in the bones and teeth. Magnesia, in the sebaceous matter of the skin. Alumina, in the enamel of the teeth ; And iron, in the black pigment in various parts. The additional elements thus brought into the organism may be enume- rated as follows: Metallic bases of earths.—Calcium, magnesium, silicium, aluminum. Metallic bases of alkalies.—Potassium, sodium. Phosphorus, sulphur, chlorine, andfluorine. Metals.—Iron, manganese, titanium, arsenic, and copper. Almost all of these elements exist compounded in either the binary or ternary form. The binary compounds are— Water, found universally consisting of HO. Carbonic acid, found in blood, urine, sweat. Carbonates, or salts of carbonic acid:— Carbonate of soda, in serum, bile, mucus, sweat, saliva, tears, carti- lage, &c. Carbonate of ammonia, in the amniotic liquor, probably derived from the urine of the foetus. Carbonate of lime, in cartilage, bone, and the teeth. Carbonate of magnesia, in the sebaceous matter of the skin. Salts of phosphoric acid:— Phosphate of soda, in serum, saliva, sweat, bones, muscles, &c. Phosphate of lime, in bones, teeth, cartilage, and the sandy concretions of the pineal gland. Phosphate of soda and ammonia, in urine and blood; but probably onlv for the purpose of being excreted or thrown off as unfit to constitute a part of an animal body. Phosphate of iron, in blood, gastric juice, and urine. Chlorine and its compounds:— Hydrochloric acid, in gastric juice, and in the fluid of the cascum. Chloride of sodium, in blood, brain, muscle, bone, cartilage, dentine, and pigment. Chloride of potassium, in blood, gastric juice, milk, saliva. Chloride of ammonium, in sweat, gastric juice. Chloride of calcium, in gastric juice. Sulphuric acid and its compounds:— Sulphate ofpotassa, in urine, gastric juice, and cartilage. Sulphate of soda, in sweat, bile, and cartilage. ' Sulphate of lime, in bile, hair, and cuticle. Sulpho-cyanide ofpotassa, in the saliva. Fluoride of calcium, in the enamel. Silica and oxide of manganese, in the hair. Alumina, in the enamel. HISTOLOGY. 35 Oxide of iron, in blood, black pigment, lens, and hair. 1 Oxide of titanium, in the capsulae renales. Ammonia and cyanogen only exist in excreted liquids, and conse- quently do not appear fit to form any part of an organism, one consisting of NH and the other of CH ; their elements may only have united for the purpose of finding a ready exit from the body through the emunc- tories. Chemistry and physiology have both failed to detect the mode in which the elements of an animal body form themselves into the ternary and quaternary compounds which are found or supposed to exist in them, and much confusion and uncertainty still prevail in regard to their compo- sition and the part they play in the animal organization. Almost all of these compounds contain nitrogen, in addition to the carbon, oxygen and hydrogen found in them; and some of them are exactly alike in their ele- mentary chemical constitution, although differing in a remarkable manner in their sensible characteristics. Those ternary or quaternary compounds which contain nitrogen are prone to rapid putrescence, and have received the generic name of nitrogenized substances. I. Nitrogenized substances. — Perhaps the best mode of explain- ing these compounds is to admit the existence of protein, which is described by Mulder, and is so called because, itself a primary sub- stance, it originates so many dissimilar substances. It consists of Ci0 H3) N5 012. By imagining it to unite with small proportions of either sulphur or phosphorus, or both, it may be said to form a number of ni- trogenized bodies. When in the moist state, protein is said to be gelatin- ous, and when dried, brittle, and of a brownish colour. It is inodorous and tasteless, insoluble in water, alcohol, or ether, but easily dissolved by all the acids in a dilute state. The substances formed by it are— 1st. Albumen (Pr10 + PS2). This substance is exceedingly common in the animal economy, and a good example of it is presented in the white of an egg, which is nearly pure albumen. It forms an admirable matrix or blastema for the generation of cells, and the consequent forma- tion of tissues. When dry, albumen is solid, brittle, and of an amber yellow colour. It is soluble in water, coagulable by heat, alcohol and acids, and forms insoluble compounds with tannin, sugar of lead, and corrosive sublimate. Very nearly resembling albumen in many of its properties is— 2d. Fib?in(Prw+ PS). This, however, possesses the power of coagu- lating, when removed from the body of a living animal, in from three to seven minutes, into a delicate rete or net-work. It is most readily ob- tained from blood, where it exists in solution, by whisking it with a bundle of twigs, which hastens its coagulation, and causes it to adhere to the twigs. When well washed with running water it presents a semi-solid condition, a dull yellowish colour, and scarcely an appreciable odour. Fibrin, in a coagulated state, forms almost the whole bulk of the muscles. 3d. Casein (Pr10+S). This substance is abundantly found in milk, and constitutes, when dried, cheese. It is soluble in water, and coagu- lated by alcohol, acids, and the stomach of any of the mammalia. Be- 36 HISTOLOGY. sides forming a constituent of milk, casein is found in blood, saliva, bile, and the lens of the eye. 4th. Pepsin. This substance was discovered by Schwann, and analysed by Vogel, who found it to be composed of C^ H32 N8 O10. It is so much like albumen that it is difficult to discover a distinction between them. It is found in the gastric glands. 5th. Globulin (Pr15-f- S) exists in the blood corpuscles; very like albu- men. 6th. Spermatin is found in semen; probably fibrin, altered and filled with living forms. 7th. Mucus consists of globules floating in a clear fluid, the constitution of each being different. 8th. Keratin (Pr S2). The product of the analysis of hair, cuticle, &c. 9th. Salivin. Found only in the saliva. Besides the protein compounds thus enumerated, we have the extractive matter, obtained by either water or alcohol from muscular flesh. The watery extract is called osmazome, is highly volatile, gives the taste and odour to soups and roast meats, and is no doubt a product of the treatment of the meat, or a new combination of the animal elements occurring during the effort to procure it. Gelatine is another substance obtained from portions of the animal body, and differs according to the tissue which furnishes it. Thus ten- dons, ligaments and bone furnish colla, or glue, which consists of C52 H40 N8 0^; whilst the cartilages and the cornea furnish chondrin, the composition of which is N32 H26 N4 014. Hematin is found in C^ H^ N3 06 united with a little iron, which is not essential to its composition or existence. A number of principles have been described as existing in the hepatic secretion or bile, but much research is yet necessary to clear up the con- fusion which exist in writings with regard to them. They may be enu- merated :—Bilin, fellinic acid, cholinic acid, taurin, dyslysin, cholepyrrhin, biliphcein, biliverdin, bilifulvin, cholesterin, oleate, mangarate, and stearate of soda, chloride of sodium, sulphate, phosphate, and lactate of soda, and phosphate of lime. Urea and uric acid, found in the urine, should not be considered as constituent parts of an animal, but as elements combined in a particular way for the purpose of being excreted. II. The non-nitrogenized compounds, found in the bodies or secretions of animals, are not numerous. When milk is dried, two-fifths of its solid contents consist of a peculiar sugar, called saccharum laclis, and composed of C5 H4 04 + H0. It crystallizes in four-sided prisms, and has a sp. gr of 1.543. It also contains an acid called lactic (C6 H- 05), common in all the fluids and secretions of the body, and united in them with either potash, soda, ammonia, lime, or magnesia. Fat consists of cells held together by areolar tissue and vessels, and is found by the chemists to contain glycerin, stearic acid, margaric acid, and elaic acid, all of which are destitute of nitrogen. The solidity of the fat of an animal depends upon the proportion of the above ingredients ;_thus, when stearic acid preponderates, the fat is solid and when elaic, fluid. HISTOLOGY. 37 OF THE TISSUES. The solids of an animal body have been divided into tissues, any one of which presents the same characteristics, no matter in what portion of the body it is found. The tissues may be further divided into simple and compound tissues ; meaning by compound those which consist of two or more simple or elementary tissues mixed together in a definite and regular manner. As an instance of this we may mention fibro-cartilage, which consists of a net-work of white fibrous tissue, having its meshes or inter- stices filled up by a cartilaginous deposit. The simplest form of animal organism is Fig. l* the nucleated corpuscle or cell, which is a little vesicle or bag, containing a fluid in its early stage, and a granular body called a nucleus, attached to some portion of the cell wall. This nucleus occasionally presents one or two distinct corpuscles in its sub- stance, which when found are called nucle- oli, and which possibly are the germs of new cells. Every portion of the animal organism is formed by these cells, and as the body is undergoing constant repro- duction and decay, they are found in various stages of development at any time in the life of an animal. division of the tissues. The animal organism may be divided into simple, or non-metamor- phosed forms, and compound, or metamorphosed forms of animal matter. They are presented in the following tabular form: 1. Simple Forms:— 1. Nucleated cells, 2. Corpuscles, 1. Formative, producing solids (durable). 2. Secreting, producing fluids (evanescent). 1. Of the blood, 2. Of the lymph, 3. Of the chyle. 2. Compound Forms :— Tissues produced by the metamorphosis of cells. into simple and compound tissues. Simple Tissues: They are divided 1. Epithelial tissue, presenting several varieties. 2. White fibrous tissue (inelastic). 3. Yellow fibrous tissue (elastic). 1. Simple membrane, 2. Pigmentary membrane, 3. Tesselated epithelium, 4. Cylindroid epithelium, 5. Ciliated epithelium, 6. Aggregated epithelium. * A group of vegetable cells. 4 ]. Nucleus. 2. Nucleoli in nucleus. 38 HISTOLOGY. 4. Cartilaginous tissue. 5. Osseous tissue. 6. Petrous tissue. Compound Tissues: , -T , ^ A. ( 1. Striped muscular fibre, 1. Muscular fibrous tissue, j 2 Un£iped muscular fibre. 2. Nerve-fibrous tissue. Binary Tissues, formed of two simple tissues: 1. Areolar tissue, constituted by the white and yellow fibrous tissues intermixed. 2. Fibro-cartilage, constituted by cartilage and white fibrous tissue intermixed. A certain difference exists between the simple corpuscles and nucleated cells. The corpuscles of the blood, for instance (in the mammalia), are destitute of a nucleus, and are persistent; whereas a nucleated cell is always in a state of progression, either producing a fluid or undergoing a transformation. The 1st variety of epithelium is found where there is a necessity for transparency, as in the capsule of the lens and the posterior layer of the cornea. The membrane in this case may be produced by the develop- ment of a very large cell and the collapse of its walls, so as to cover the whole area, thus constituting a duplicate lamina. The 2d variety is formed of hexagonal plates, adhering to each other and containing a form of carbon ; it is found in the eye, in the lung, and mixed with the cuticle and hair of the negro. The 3d variety constitutes the free surface of many membranes, as the skin, the mucous and serous; it may be found in a single lamina, forming a pavement of nucleated cells, flattened and adhering by their edges ; or it may form superimposed laminae, the exterior of which is constantly peeling off, and the interior as constantly reproducing new cells to keep up the covering. This is the case in the cuticle, and in the mucous membranes of the mouth, oesophagus, rectum, &c. The 4th variety exists in mucous membranes, and consists of conoidal nucleated cells, very firmly paved together. The 5th variety differs only from the last in having the base furnished with vibratile ciliae, which diffuse the secretion, moistening the surface by their constant motion. This kind of epithelium occurs' in mucous and serous membranes, where the surfaces cannot come together and rub against each other, as in the ventricles of the brain, the trachea, &c. Nails, hairs, and horny excrescences, are manifestly modifications of epithelium, and are hence included in the enumeration as constituting the sixth variety of that tissue. The White fibrous tissue exists in ligaments and tendons, and consti- tutes the principal part of the derm or cutis vera. It is inelastic and in- extensible. The Yellow fibrous tissue is found in the ligamenta flava of the spine, in the middle coat of the arterial system, and in the skin, mixed with the white fibrous element. The Cartilaginous tissue constitutes the cartilage of the ribs, and the HISTOLOGY. 39 articular coverings for the ends of the bones. It is also found existing transitorily in the process of osteo-genesis. The Osseous tissue constitutes the skeleton, and, with some modification, the ivory of the teeth or dentine. The Petrous tissue presents the extreme of departure from the animal organization, consisting almost entirely of crystals, which are chiefly com- posed of phosphate of lime. It is found in the enamel of the teeth, in the otoconites, and in the concretions of the pineal gland. The Muscular fibrous tissue constitutes the apparatus of motion, and is divided into two distinct varieties,—striped, or the muscular fibre of ani- mal life ; and unstriped, or the muscular fibre of organic life:—the former acting in obedience to the will, and the latter being wholly independent of it. The Nerve fibre is the conducting portion of the nervous system, and is like the muscular compound, being formed of two distinct substances, the one containing and the other contained. The Binary tissues are merely the intermixture or co-existence of two elementary tissues, the proportions of which vary according to the exigen- cies of the part of the body in which they are found. The grey or vesicular nervous matter consists of secreting cells, which disappear and are reproduced. Adipose tissue consists also of secreting cells, which retain their con- tents under certain circumstances for a great length of time, while under others they rapidly disappear. The vascular, mucous, and serous tissues of older writers, consist of aggregations of areolar, muscular, and epithelial tissues, variously modified. ^PROPERTIES OF THE TISSUES. The Chemical Properties have beep given in the early portion of this chapter. physical properties of the tissues. The tissues, like other forms of matter, possess certain physical proper- ties, such as colour, consistency, and density, which it is necessary to describe under their respective heads. One property, however, is enjoyed by every tissue, and this seems to play a most important part in the main- tenance of the functions of life. I allude to the transudation of the solids by the fluids, which is known by the title of endosmosis and exosmosis, names by which the process was designated by Dutrochet, its discoverer. All the tissues contain a certain quantity of water, and in some cases this amounts to four-fifths of their weight, as may be proved by drying them ; and this water is essential, not only to their vitality, but confers upon them their organic properties—pliability and elasticity. As the tissues imbibe water in certain quantity, it becomes a subject of study to discover the manner by which the quantity may be increased. It is well understood how pressure from without would produce this effect, but even this would be aided by the natural tendency to imbibe and retain an additional quan- tity of water under favourable circumstances, which is strongly exhibited by the softer tissues. Such a tissue saturated with water placed in contact with another tissue or a fluid having a higher affinity for water than it has, will part with its superabundance, and if not supplied from behind will 40 HISTOLOGY. even part with a portion of that which is essential to its normal condition. If, however, it is supplied from the other side, it will continue to supply the imbibing fluid and receive more from behind. Thus a current will be established from the water on one side of the tissue to the fluid having a high affinity for it on the other; but this is not all: for the fluid alluded to, not content with absorbing all the water which the animal tissue sup- plies it with, in its turn transudes the tissue to get at and mix with the water on the other side, and thus a counter-current is set up in an oppo- site direction, which is slower, however, than the former one. These are the currents which are termed endosmotic and exosmotic, and which con- tinue until the difference between the two liquids ceases, and they are equally saturated«by each other. vital properties. The most prominent vital property possessed by the tissues is the power of assimilation, or of appropriating to themselves such of the organizable substances presented to them as may suit their purposes. This power is supposed to be partly due to chemical affinity, and partly to vital affinity. It is most probable, however, that future researches will prove that the power of assimilating is subject to the ordinary chemical laws, but under modifying circumstances, which can only exist in a living body or tissue. To this may be added the power of reproducing, in its appropriate place, a new portion of a tissue, when injured or destroyed. Another property which is essentially vital is contractility—a phenome- non which is made manifest by the visible shrinking or contraction of a living tissue when irritated, either by mechanical or chemical stimuli. The muscular tissue exhibits this property in the highest degree. This contractility must be distinguished from the permanenc contraction or crispation which a part suffers when exposed to a high temperature. A third vital property is sensibility, which, however, requires that the tissues shall be united so as to form a continuous line from the part mani- festing it to the brain. This property is enjoyed in very different degrees by the different tissues, and constitutes an important distinction between them, depending upon the presence and number of nerve-fibres mixed with the tissue. DEVELOPMENT OF THE TISSUES. The tissues, however diversified in form, are all developed in the fol- lowing manner: A nucleated cell attracts from the blastema in which it is formed, or from the capillary vessels contiguous to it, certain elements which combine in its interior, and either form a portion of the animal body,—in which case the remains of the cell, and particularly its nucleus, continue to exist in the part, and can be made evident by chemical agents under the microscope,—or they become filled with a fluid, and bursting when ripe, and mixing and flowing along with their former contents, are discharged into a tube or duct, and constitute a secretion or a secreted fluid. The only difference between these two kinds of cell, which we designate by the terms formative and secreting, is that the former secrete a solid or semi-solid, which remains in the body with the debris of the cell for an .appreciable period of time, whilst the latter secrete a fluid which escapes from the HISTOLOGY. 41 body with the remains of the cell which gave it birth. Each of these little bodies may be compared to a laboratory, which receives from the surrounding matter the elements which it requires, and combines them so as to produce a desired result. The various modifications and aggregations of these cells constitute the varied forms of animal and vegetable tissues. DEVELOPMENT OF CELLS. A cell originates in a mass of soft or liquid matter, which is organizable or capable of being organized. In other words, a liquid formed of a com- bination of elements fitted to produce an organized structure. This sub- stance is called "blastema." As an example, we may take the liquor sanguinis or the blood, excluding its globules, which in a fully formed animal is a universally diffused blastema. A minute point (see Fig. 2) arises in this blastema, which increases in size; a transparent wall is seen to spring up like a watch-glass from one side of the granule, which swells up more and more until the granule is seen to exist in, and adhere to the side of the cell wall. When thus formed, we have the cell wall with its fluid contents, and the granule or nucleus, which may by this time have developed several new granules or nucleoli in its interior. Fig. 2* MULTIPLICATION OF CELLS. Cells are multiplied in several modes: 1st. By repetition, i. e., of the development from a blastema, as ex- plained. 2d. By the development of new nuclei and cells within the parent cell- wall (see fig. 3). Fig. 3.t Fig. 4.* 3d. By the development of new cells from the parietes of pre-existing ones. This is shown in fig. 4. TRANSFORMATION OF CELLS. 1st. Cells may lose their fluid contents, and their walls collapsing until they come in contact and adhere, they form simple, membranous, and transparent discs. • Development of cell from blastema. On the left is seen the corpuscle which be comes the nucleus; on the right the complete nucleated cell. + Development of new cells within the parent cell. $ Development of new cells from the outer wall of pre-existing cells. 4* 42 HISTOLOGY. 2d. Cells may elongate so as to form tubes or solid rods ; in the former case they adhere by their ends to neighbouring cells, and their cavities mutually open into each other, thus forming a vessel: in the latter the fluid content is lost, and a rod or fibre is the result. Curious forms are produced by a modification of the same law, as exemplified in fig. 5. 3d. Solid deposits may occur within the cell wall, obliterating its cavity. 4th. The same thing may occur in the blastema, exterior to the cell walls, and thus a solid will result. Examples of the third and fourth kind occur in the formation of cartilage, as is illustrated in the accompa- nying cuts. Fig. 6.f Fig. 7.f Fig. 8.f Fig. 9.* Fig. 10.§ 5th. A curious modification of development occurs in the feathers of birds, where a nucleated cell elongates and becomes filled with fibres; the a cell wall is rubbed off by attrition, and the fibres are thus uncovered and exposed. See fig. 10, a, b, c. b Finally, it is believed by some that the blastema may form a simple membrane or fibre without the intervention of a cell, although this is by no means proved. * Curious forms of cell transformation usually found in abnormal deposits. ■j- Development of cartilage. i Deposit in layers of lignin in the interior of vegetable cells. § Mode of formation of the feathers of a bird in the interior of a nucleated cell. CLASSES OF BONE. 43 CHAPTER II. OSTEOLOGY. The bones are the organs of support to the animal frame; they give firmness and strength to the entire fabric, afford points of connection to the numerous muscles, and bestow individual character upon the body. In the limbs they are hollow cylinders, admirably calculated by their con- formation and structure to resist violence and support weight. In the trunk and head, they are flattened and arched, to protect cavities and provide an extensive surface for attachment. In some situations they present projections of variable length, which serve as levers; and in others are grooved into smooth surfaces, which act as pulleys for the passage of tendons. Moreover, besides supplying strength and solidity, they are equally adapted, by their numerous divisions and mutual apposition, to fulfil every movement which may tend to the preservation of the creature, or be conducive to his welfare. According to the latest analysis by Berzelius, bone is composed of about one-third of animal substance, which is almost completely reducible to gelatine by boiling, and of two-thirds of earthy and alkaline salts. The special constituents of bone are present in the following proportions:— Cartilage............32-17 parts. Blood-vessels...........1'13 Phosphate of lime..........51-04 Carbonate of lime.........11-30 Fluate of lime ...........2-00 Phosphate of magnesia........1-16 Soda, chloride of sodium.......1-20 100-00 Bones are divisible into three classes:—Long,flat, and irregular. The Long bones are found principally in the limbs, and consist of a shaft and two extremities. The shaft is cylindrical or prismoid in form, dense and hard in texture, and hollowed in the interior into a medullary canal. The extremities are broad and expanded, to articulate with ad- joining bones ; and cellular or cancellous in internal structure. Upon the exterior of the bone are processes and rough surfaces for the attachment of muscles, and foramina for the transmission of vessels and nerves. The character of long bones is, therefore, their general type of structure and their divisibility into a central portion and extremities, and not so much their length ; for there are some long bones, as the second phalanges of the toes, which are less than a quarter of an inch in length, and almost equal, and in some instances exceed, in breadth their longitudinal axis. The long bones are, the clavicle, humerus, radius and ulna, femur, tibia and fibula, metacarpal bones, metatarsal, phalanges, and ribs. Flat bones are composed of two layers of dense bone with an interme- diate cellular structure, and are divisible into surfaces, borders, angles, and processes. They are adapted to inclose cavities; have processes upon their surface for the attachment of muscles; and are perforated by foramina, for the passage of nutrient vessels to their cells, and for the transmission 44 STRUCTURE OF BONE. Fig. 11* of vessels and nerves. They articulate with long bones by means of smooth surfaces plated with cartilage, and writh each other either by fibrous tissue, as at the symphysis pubis; or by suture, as in the bones of the skull. The two condensed layers of the bones of the skull are named tables; and the intermediate cellular structure, diploe. The flat bones are the occipital, parietal, frontal, nasal, lachrymal, vomer, sternum, scapulae, and ossa innominata. The Irregular bones include all that remain after the long and the flat bones have been selected. They are essentially irregular in their form, in some parts flat, in others short and thick. In preceding editions of this work the short and thick bones were made a separate class, under the name of short bones. This subdivision has been found to be disadvan- tageous, besides being arbitrary, and is, therefore, now omitted. Irregular bones are constructed on the same general principles with other bones; they have an exterior dense, and an interior more or less cellular. The bones of this class are, the temporal, sphenoid, ethmoid, superior maxil- lary, inferior maxillary, palate, inferior turbinated, hyoid, vertebras, sacrum, coccyx, carpal and tarsal bones, and sesamoid bones, including the patellae. Structure of Bone.—Bone is a dense, compact, and homogeneous sub- stance (basis substance) filled with minute cells (corpuscles of Purkinje), which are scattered numerously through its structure. The basis substance of bone is subfibrous and obscurely lamellated, the lamellae being concentric in long and parallel in flat bones; it is traversed in all directions, but es- pecially in the longitudinal axis, by branching and inosculating canals (Haversian canals), which give passage to vessels and nerves, and in certain situations the la- mellae separate from each other, and leave between them areolar ' spaces (cancelli) of various mag- nitude. The lamellae have an average diameter of ^m of an inch, and, besides constituting the general structure of the basis sub- stance, are collected concentrically around the Haversian canals, and form boundaries to those canals of about 2^ of an inch in thickness. The number of lamellae surround- ing each Haversian canal is com- monly ten or fifteen, and the di- ameters of the canals have a me- dium average of Bfo of an inch. The cancelli of bone, like its compact substance, have walls which are composed of lamellae; and, such is the * Minute structure of bone, drawn with the microscope from nature, by Basg. Mag- nified 300 diameters. 1. One of the Haversian canals surrounded by its concentric lamellas. The corpuscles are seen between the lamellse; but the calcigerous tubuli are omitted. 2. An Haversian canal with its concentric lamelhe, Purkinjean corpuscle* and tubuli. 3. The area of one of the canals. 4, 4. Direction of the lamella of the great medullary canal. Between the lamellae at the upper part of the figure several very long corpuscles with their tubuli are seen. In the lower part of the figure' the out- lines of three other canals are given, in order to show their form and mode of 'arrange- ment in the entire bone. 5 DEVELOPMENT OF BONE. 45 similarity in structure of the parts of a bone, that the entire bone may be compared to an Haversian canal of which the medullary cavity is the mag- nified channel; and the Haversian canals may be likened to elongated and ramified cancelli. The Haversian canals are smallest near the surface of a bone, and largest near its centre, where they gradually merge into cancelli; by the frequent communications of their branches they form a coarse network in the basis substance. Fig. 12 * The cells of bone, or corpuscles of Purkinje, are thickly disseminated through the basis substance; they are irregular in size and form, give off numerous minute branching tubuli, which radiate from all parts of their circumference, and in the dried state of the bone contain merely the remains of membranous cells and some calcareous salts, f In the living bone, the cells and their tubuli are probably filled with a nutritive fluid holding calcareous salts in solution. The form of the cells is oval or round, and more or less flattened, their long diameter corresponds with the long axis of the bone, and their tubuli cross the direction of the lamellae, and constitute a very delicate network in the basis substance, by communicating with each other, and with the tubuli of neighbouring cells. The tubuli of the cells nearest the Haversian canals terminate upon the internal surface of those cavities. The size of the cells varies in extreme measurement from 5o1oo"to s^ of an inch in their long diame- ter, an ordinary average being yo'oo; the breadth of the oval cells is about one-half or one-third their length, and their thickness one-half their breadth. They are situated between the lamella;-, to which circum- stance they owe their compressed form. * The above cut, which I have introduced to supply the manifest deficiency of Mr. Wilson's representation, is from a section of a human femur, about its middle, and ex- hibits the erratic course of the Haversian canals, and their relations to each other, and at the same time the general laminated condition of a long bone. This laminated con- dition is well shown by polarized light, which causes the corpuscles to disappear, and the lamina? to come out boldly.—G. -f-Miiller and Henle conceived that the bone cells and tubuli were the principal seat of the calcareous matter. Hence they have been named calcigerous cells and tubuli. 46 DEVELOPMENT OF BONE. In the fresh state, bones are invested by a dense fibrous membrane, the periosteum, which covers every part of their surface, with the excep- tion of the articular extremities, the latter being coated by a thin layer of cartilage. The periosteum of the bones of the skull is termed peri- cranium ; and the analogous membrane of external cartilages, perichon- drium. Lining the interior of the medullary canal of long bones, the Haversian canals, the cells of the cancelli, and the cells of short, flat, and irregular bones, is the medullary membrane, which acts as an internal periosteum. It is through the medium of the vessels ramifying in these membranes that the changes required by nutrition occur in bones, and the secretion of medulla into their interior is effected. The medullary canal, Haversian canals, and cells of long bones, and the cells of other bones, are filled with a yellowish oily substance, the medulla, which is contained in a loose areolar tissue formed by the medullary membrane. Development of Bone.—To explain the development of bone it is ne- cessary to inform the student, that all organized bodies, whether belong- ing to the vegetable or the animal kingdom, are developed primordially from minute vesicles. These vesicles, or, as they are commonly termed, cells, are composed of a thin membrane containing a fluid or granular matter, and a small rounded mass, the nucleus, around which the cell was originally formed. Moreover, the nucleus generally contains one or more small round granules, the nucleolus or nucleoli. From cells having this structure all the tissues of the body are elaborated; the ovum itself originally presented this simple form, and the embryo at an early period is wholly composed of such nucleated cells. In their relation to each other, cells may be isolated and independent, as is exemplified in the corpuscles of the blood, chyle, and lymph; secondly, they may cohere by their surfaces and borders, as in the epiderma and epithelium; thirdly, they may be connected by an intermediate substance, which is then termed intercellular, as in cartilage and bone; and fourthly, they may unite with each other in rows, and upon the removal, by liquefaction, of the adherent surfaces, be converted into hollow tubuli. In the latter mode capillary vessels are formed, as also are the tubuli of nerve and muscular fibre. One of the properties of cells may also be adverted to in this place ; it is that of reproducing similar cells in their interior. In this case the nucleoli become the nuclei of the secondary cells, and as the latter increase in size, the membrane of the primary or parent cell is lost. Bone, in its earliest stage, is composed of an assemblage of these mi- nute cells, which are soft and transparent, and are disposed within the embryo in the site of the future skeleton. From the resemblance which the soft tissue bears to jelly, this has been termed the gelatinous stage of osteo-genesis. As development advances, the cells, heretofore loosely collected together, become separated by the interposition of a transparent intercellular substance, which is at first fluid, but gradually becomes hard and condensed. The cartilaginous stage of osteo-genesis is now esta- blished, and cartilage is shown to consist of a transparent matrix, having minute cells disseminated at pretty equal distances, and without order, through its structure. Coincident with the formation of cartilage is the development of vascular canals in its substance, the canals beino- formed by the union of the cells in rows, and the subsequent liquefactio°n of the adhering surfaces. The change which next ensues in the concentration of the vascular canals towards some one point; for example, the centre DEVELOPMENT OF BONE. 47 bl 10 <3 A Q ^*> of the shaft in a long, or the mid-point of a flat bone, and here the punctum ossificationis, or centre of ossification, is established. What determines the vascular concentration now alluded to, is a question not easily solved, but that it takes place is certain, and the vascular punctum is the most easily demonstrable of all the phenomena of ossification. During the formation of the punctum ossificationis, g' changes begin to be appa- rent in the cartilage cells. Originally they are simple nucleated cells (5^^ to Woo °f an mcn m diame- ter), having a rounded form. As growth pro- ceeds, they become elon- gated in their figure, and it is then perceived that each cell contains two and often three nucleoli, around which smaller cells are in progress of formation. 0 a <0@ <3 % @ •a}« Nearer still to the punctum ossificationis "» Fig. 15.+ • If we examine them nearer to the punctum ossificationis, we find that the young or secondary cells have each attained the size of the pa- rent cell (anini of an inch), the membrane of the parent cell has disappeared, and the young cells are separated to a short distance by freshly effused intercellular substance. a more remarkable change has ensued, the energy of cellule reproduction has augmented with proximity to the os- sifying point, and each cell in place of producing two, gives birth to four, five, or six young cells, which rapidly de- * Figures illustrative of the 4evelopment of bone; they are magnified 155 times, and drawn with the camera lucida. 1. A portion of cartilage the farthest removed from the seat of ossification, showing simple^nucleated cells, having an ordinary size of ?d».- of an inch, long diameter, b. The same cartilage, nearer the seat of ossification; each simple cell has produced two, which are a little larger than the cells in figure a. + The same cartilage, still nearer the seat of ossification; each single cell of b has given birth to four, five, or six cells, which form clusters. These clusters become larger towards the right of the figure, and their cells more numerous and larger, T^n of an inch, long diameter. . * The same cartilage at the seat of ossification; the clusters of cells are arranged in columns; the intercellular spaces between the columns being ^J,^ of an inch in fft&* i) f. 48 DEVELOPMENT OF BONE. stroy the parent membrane and attain a greater size (f .^go" of an inch) than the parent cell, each cell being, as in the previous case, separated to a slight extent from its neighbour by intercellular substance. By one a her repetition of the same process, each cell producing four, or five, or six young cells, a cluster is formed, containing from thirty to fifty cells. These clusters lie in immediate relation with the punctum ossificationis ; they are oval in figure (about ^q in length by 5^ in breadth), and placed in the direction of the longitudinal axis of the bone. The cells composing the cluster lie transversely with regard to its axis. In the first instance they are closely compressed, but by degrees are parted by a thin layer of inter- cellular substance, and each cluster is separated from neighbouring clus- ters by a broader layer (3^^ of an inch) of intercellular substance. Such are the changes which occur in cartilage preparatory to the formation of bone. y Ossification is accomplished by the formation of very fine and delicate fibres within the intercellular substance: this process commences at the punctum ossificationis, and extends from that point through every part of the bone, in a longitudinal direction in long, and in a radiated manner in flat bones. Starting from the punctum ossificationis, the fibres embrace each cluster of cells, and then send branches between the individual cells of each group. In this manner the network, characteristic of bone, is formed, while the cells by their conjunction constitute the permanent areolae and Haversian canals. With a high magnifying power, the deli- cate ossific fibres here alluded to are seen themselves to be composed of . minute cells having an elliptical form and central nuclei. These cells attract into their interior the calcareous salts of the blood, and their nuclei become developed, as I believe, into the future corpuscles of Purkinje. It is possible also that some of the cartilage cells become corpuscles of Purkinje in the fully developed bone. During the progress of the phenomena abe.ve described, the contents of the cells undergo certain changes. At first, their contents are transpa- rent, then they become granular^and still later opaque, from the presence of amorphous matter mingled with nuclei, nucleoli, and the remains of secondary cells. In the latter state tjAy also contain an abundance of minute oil-globules. These latter/rfTcrease in size as the ossific changes advance, and in the newly formed osseous areolae they are very numerous and have attained the ordinary size of ad*ipose cells. Cartilaginification is complete in the human embryo at about the sixth week; and the first point of ossification, is observed in the clavicle at about the seventh week. Ossification commences at the centre, and thence proceeds towards the surfa^ef in flat bones the osseous tissue ra- diates between two membranes from a central point towards the periphery, in short bones from a centre towards the'circumference, and in long bones from a central portion, diaphysis, towards a^seiondary centre, epiphysis, .situated at each extremity. Large processes, as the trochanters, are pro- vided with a distinct centre of developiient, which is named apophysis. breadth. To the right of the figure osseous fibres are seen occupying the intercellular spaces, at first bounding the clusters laterally, then splitting them longitudinally, and encircling each separate cell. The greater opacity of the right-hand border is due to a threefold cause, the increase of osseous fibres, the opacity of the contents of the cells, and the multiplication of oil-globules. In the lower part of the figure some attemp' has been made to show the texture of the cells. * DEVELOPMENT OF BONE. 49 The growth of bone in length takes place at the extremity of the dia- physis, and in bulk by fresh deposition on the surface; while the medul- lary canal is formed and increased by absorption from within. The period of ossification is different ill different bones; the order of succession may be thus arranged :— During the fifth week, ossification commences in the clavicle, lower jaw, and upper jaw. During the sixth week, in the femur, humerus, tibia, radius, and ulna. During the seventh and eighth weeks, in the fibula, frontal, occipital, sphenoid, ribs, parietal, temporal, nasal, vomer, palate, vertebrae, first three pieces of sacrum, malar, metacarpus, metatarsus, third phalanges of the hands and feet, and ilium. During the third month, in the first and second phalanges of the hands and feet, lachrymal bone, and ischium. During the fifth month, in the mastoid portion of the temporal, ethmoid, inferior turbinated, sternum, os pubis, and last two pieces of sacrum. During the sixth month, in the body and odontoid process of the axis, and in the calcaneus. During the seventh month, in the astragalus. During the tenth month, in the cuboid bone and os hyoides. During the first year, in the coracoid process of the scapula; first piece of the coccyx, inferior turbinated bone, last piece of the sternum, anterior arch of the atlas, os magnum, os unciforme, and external cuneiform bone. During the third year, in the cuneiform of the carpus, internal cuneiform of the tarsus, and patella. During the fourth year, in the middle cuneiform and scaphoid of the tarsus. During the fifth year, in the trapezium and os semilunare. During the seventh year, in the second piece of the coccyx. During the eighth year, in the scaphoid of the carpus. During the ninth year, in the os trapezoides. During the twelfth year, in the os fisiforme and third piece of the coccyx. During the eighteenth year, in the fourth piece of the coccyx. The ossicula auditus are the only bones completely ossified at birth; the vertebrae are not completed until the five-and-twentieth year. The entire osseous framework of the body constitutes the skeleton, which in the adult man is composed of two hundred and forty-six distinct bones. They may be thus arranged::— Head . • :...........8 Ossicula auditus..........6 Face..............14 Teeth.............32 Vertebral colump, including sacrum and coccyx 26 Os hyoides, sternum, and ribs......26 Upper extremities..........64 LowTer extremities..........62 Sesamoid bones..........8 246 The skeleton is divisible into: 1. The vertebral column, or central axis. 2. The head and face, or superior development of the central axis. 3, 5 d 50 VERTEBRAL COLUMN. The hyoid arch. 4. The thoracic arch and upper extremities. 5. The pelvic arch and lower extremities. VERTEBRAL COLUMN. The vertebral column is the first and only rudiment of internal skeleton in the lower Vertebrata, and constitutes the type of that great division of the animal kingdom. It is also the first developed portion of the skeleton in man, and the centre around which all the other parts are produced. In its earliest formation it is a simple cartilaginous cylinder, surrounding and protecting the primitive trace of the nervous system; but, as it advances in growth and organisation, it becomes divided into distinct pieces, which constitute vertebra. The vertebrae are divided into true and false. The true vertebrae are twenty-four in number, and are classified, according to the three regions of the trunk which they occupy, into cervical, dorsal, and lumbar. The false vertebrae consist of nine pieces united into two bones, the sacrum and coccyx. The arrangement of the vertebrae may be better comprehended by means of the accompanying table:— C 7 Cervical, True vertebrae 24 < 12 Dorsal, ( 5 Ljumbar. False vertebrae 9 \ . >,a r m' ( 4 Coccyx. Characters of a Vertebra.—A vertebra consists of a body, two laminae, a spinous process, two transverse processes, and four articular processes. The body is the solid part of the vertebra; and, by its articulation with adjoining vertebrae, gives strength and support to the trunk. It is flattened above and below, convex in front, and slightly concave behind. Its an- terior surface is constricted around the middle, and pierced by a number of small openings which give passage to nutritious vessels.. Upon its pos- terior surface is a single irregular opening, or several, for the exit of the venae basis vertebrae. The laminae commence upon the sides of the posterior part of the body of the vertebra by two pedicles; they then expand; and, arching back- wards, enclose a foramen which serves for the protection of the spinal cord. The upper and lower borders of the laminae are rough for the at- tachment of the ligamenta subfiava. The concavities above and below the pedicles are the intervertebral notches. The spinous process stands back- wards from the angle of union of the laminae of the vertebra. It is the succession of these projecting processes along the middle line of the back, that has given rise to the common designation of the vertebral column, the spine. The use of the spinous process is for the attachment of muscles. The transverse processes project one at each side from the laminae of the vertebra; they are intended for the attachment of the muscles. The arti- cular processes, four in number, stand upwards and downwards from the laminae of the vertebra, to articulate with the vertebra above and below. Cervical Vertebrae.—In a cervical vertebra the body is smaller than in the other regions; it is thicker before than behind, broad from side to side, concave on the upper surface, and convex below; so that when articulated, the vertebrae lock the one into the other. The laminae are CERVICAL VERTEBRAE. 51 narrow and long, and the included spinal fo- ramen large and triangular. The superior in- tervertebral notches are slightly deeper than the inferior; the inferior being the broadest. The spinous process is short and bifid at the extre- mity, increasing in length from the fourth to the seventh. The transverse processes are also short and bifid, and deeply grooved along the upper surface for the cervical nerves. Piercing the base of the transversa process is the vertebral foramen f, which gives passage to the vertebral artery and vein, and vertebral plexus of nerves. The transverse processes in this region are formed by two small developments which proceed, the one from the side of the body, the other from the pedicle of the vertebra, and unite near their extremities to enclose the circular area of the vertebral foramen. The anterior.of these developments is the rudiment of a cervi- cal rib ; and the posterior, the analogue of the transverse processes in the dorsal region. The extremities of these developments are the anterior and posterior tubercles of the transverse process. The articular processes are oblique ; the superior looking upwards and backwards; and the infe- rior, downwards and forwards. There are three peculiar vertebrae in the cervical region:—The first, or atlas; the second, or axis; and the seventh, or vertebra prominens. The Atlas (named from supporting the head) is a simple ring of bone, without body, and composed of arches and processes. The anterior arch has a tubercle on its anterior surface, for the attachment of the longus colli muscle : and on its posterior aspect is a smooth surface, for the articulation of the odontoid process of the axis. The posterior arch is longer and more slender than the anterior, and flattened from above downwards; at its middle is a rudimentary spinous process; and upon its upper surface, near the articular pro- . cesses, a shallow groove§ at each side, which represents a superior intervertebral notch, and supports the vertebral artery previously to its passage through the dura mater, and the first cervical nerve. * A centra! cervical vertebra, seen upon its upper surface. 1. The body, concave in the middle, and rising on each side into a sharp ridge. 2. The lamina. 3. The pedi- cle, rendered concave by the superior intervertebral notch. 4. The bifid spinous process. 5. The bifid transverse process. The figure is placed in the concavity between the an- terior and posterior tubercles, between the two processes which correspond with the rudimentary rib and the true transverse process. 6. The vertebral foramen. 7. The superior articular process, looking backwards and upwards. 8. The inferior articular process. + Sometimes, as in a vertebra now before me, a small additional opening exists by the side of the vertebral foramen, in which case it is traversed by a second vein. $ The upper surface of the atlas. 1. The anterior tubercle projecting from the ante- " rior arch. 2. The articular surface for the odontoid process upon the posterior surface of the anterior arch. 3. The posterior arch, with its rudimentary spinous process. 4. The intervertebral notch. 5. The transverse process. 6. The vertebral foramen. 7. Superior articular surface. 8. The tubercle for the attachment of the transverse liga- ment. The tubercle referred to is just above the head of the figure; the convexity be low it is the margin of the inferior articulating process. § This groove is sometimes converted into a foramen. 52 ATLAS AND AXIS—VERTEBRA JPROMINENS. The intervertebral notches are peculiar, from being situated behind the articular processes, instead of before them as in the other vertebra;. The transverse processes are remarkably large and long, and pierced by the foramen for the vertebral artery. The articular processes are situated upon the most bulky and strongest part of the atlas. The superior are oval and concave, and look inwards, so as to form a kind of cup for the condyles of the occipital bone, and are adapted to the nodding movements of the head; the inferior are circular, and nearly horizontal, to permit of the ro- tatory movements. Upon the inner face of the lateral mass which sup- ports the articular processes, is a small tubercle at each side, to which the extremities of the transverse ligament are attached, a ligament which di- vides the ring of the atlas into two unequal segments; the smaller for receiving the odontoid process of the axis, and the latter to give passage to the spinal cord and its membranes. The Axis (vertebra dentata) is so named from having a process upon which the head turns as on a pivot. The body is of large size, and sup- ports a strong process, the odontoid, which rises perpendicularly from its upper surface. The odontoid process presents two articulating surfaces; one on its anterior face, to articulate with the anterior arch of the atlas; the other on its posterior face, for the transverse ligament; the latter sur- face constricts the base of the process, which has given rise to the term neck applied to this part. Upon each side of its apex is a rough depression, for the attachment of the alar ligaments; and running down from its base on the anterior surface of the body of the vertebra s vertical ridge, with a depression at each side for the attachment of the longus colli muscle. The lamina are large and strong, and unite posteriorly to form a long and bifid spinous process, which is concave beneath. The transverse processes are quite rudimentary, not bifid, and project only so far as to enclose the vertebral foramen, which is directed obliquely outwards instead of perpendicu- larly as in the other vertebrae. The superior articulating processes are situated upon the body of the vertebra on each side of the odontoid process. They are circular and nearly horizontal, having a slight inclination out- wards. The inferior articulating processes look downwards and forwards, as do the same processes in the other cervical vertebrae. The superior in- tervertebral notch is remarkably shallow, and lies behind the articular pro- cess as in the atlas. The lower surface of the body is convex, and is received into the concavity upon the upper surface of the third vertebra. The Vertebra prominens, or seventh cervical, approaches in character to the upper dorsal vertebrae. It has received its designation from havinc a very long spinous process, which is single and terminated by a tubercle" and forms a considerable projection on the back part of the neck ;* to the extremity of this process the ligamentum nuchae is attached. The trans- verse processes are but slightly grooved along the upper surface, have * A lateral view of the axis. 1. The body; the figure is placed on the depression which gives attachment to the longus colli. 2. The odontoid process. 3. The smooth facet on the anterior surface of the odontoid process which articulates with the anterior arch of the atlas; the facet for the transverse ligament is beneath No. 2, where the constriction called the neck of the odontoid process is seen; the bulk of the process be- tween 2, 3, would represent its head. 4. The lamina. 5. The spinous process. 6. The transverse process, pierced obliquely by the vertebral foramen. 7. The superior articular surface. 8. The inferior articular process. DORSAL VELRTEBR^—LUMBAR VERTEBRAE. 53 each a small foramen for the transmission of the vertebral vein, and pre- sent only a rudimentary bifurcation at their extremity. Sometimes the anterior tubercle represents a small but distinct rib. Dorsal Vertebrae.—The body of a dorsal vertebra is as long from before backwards as from side to side, particularly in the middle of the dorsal region; it is thicker behind than before, and marked on each side by two half-articulating surfaces for the heads of two ribs. The pedicles are strong, and the lamina broad and thick; the spinal foramen small and round, and the inferior intervertebral notch of large size, the superior can scarcely be said to exist. -The spinous process is long, prismoid, directed very obliquely downwards, and terminated by a tubercle. The transverse processes are large and strong, and directed obliquely back- wards. Upon the anterior and superior as- pect of their summits is a small facet for the articulation of the tubercle of a rib. The ar- ticular processes are vertical, the superior facing directly backwards, and the inferior directly forwards. The peculiar vertebrae in the dorsal region are the first, ninth, tenth, eleventh, and twelfth. The first dorsal vertebra approaches very closely in character to the last cervical. The body is broad from side to side, and concave above. The superior articular processes are oblique, and the spinous process horizontal. It has an entire articular surface for the first rib, and a half surface for the second. The ninth dorsal vertebra has only one half articular surface at each side. The tenth has a single entire articular surface at each side. The eleventh and twelfth have each a single entire articular surface at each side; they approach in character to the lumbar vertebrae ; their transverse processes are very short, trifid at their summits, and have no articulation with the corresponding ribs. The transverse processes of the twelfth dorsal vertebra are quite rudimentary, and its inferior articular processes look outwards. Lumbar Vertebra.—These are the largest pieces of the vertebral column. The body is broad and large, and thicker before than behind. The pedicles very strong; the la- mina short, thick, and broad ; the inferior intervertebral notches very large, and the spinal foramen large and oval. The spin- ous process is thick and broad. The trans- verse processes (costiform processes) are slender, pointed, and directed only slightly * A lateral view of a dorsal vertebra. 1. The body. 2, 2. Articular facets for the heads of ribs. 3. The pedicle. 4. The superior intervertebral notch. 5. The inferior intervertebral notch. 6. The spinous process. 7. The extremity of the transverse pro- cess, marked by an articular surface for the tubercle of a rib. 8. The two superior articular processes looking backwards. 9. The two inferior articular processes looking forwards. + A lateral view of a lumbar vertebra. 1. The body. 2. The pedicle. 3. The su- perior intervertebral notch. 4. The inferior intervertebral notch. 5. The spinous pro- cess. 6. The transverse process. 7. The superior articular processes. 8. The inferior articular processes. 9. The posterior transverse process. 5* Fig. 20.f 54 LUMBAR VERTEBRAE. backwards. The superior articular processes are concave, and look back- wards and inwards; the inferior convex, and look forwards and outwards. Projecting backwards and upwards from the superior articular process is a short and flattened tubercle or posterior transverse process, and in a strongly marked vertebra there is not unfrequently at the base of this a smaller tubercle which has a direction downwards. The last lumbar ver- tebra differs from the rest in having the body very much bevelled poste- riorly, so as to be thick in front and thin behind, and the transverse pro- cess thick and large. General Considerations.—Viewed as a whole, the vertebral column represents two pyramids applied base to base, the superior being formed by all the vertebrae from the second cervical to the last lumbar, and the inferior by the sacrum and coccyx. Examined more attentively, it will be seen to be composed of four irregular pyramids, applied to each other by their smaller extremities and by their bases. The smaller extremity of the uppermost pyramid is formed by the axis, or second cervical ver- tebra ; and its base, by the first dorsal. The second pyramid is inverted; having its base at the first dorsal, and the smaller end at the fourth. The third pyramid commences at the fourth dorsal, and gradually enlarges to the fifth lumbar. The fourth pyramid is formed by the sacrum and coccyx. The bodies of the vertebrae are broad in the cervical region; narrowed almost to an angle in the middle of the dorsal, and again broad in the lumbar region. The arches are broad and imbricated in the cervical and dorsal regions, the inferior border of each overlapping the superior of the next; in the lumbar region an interval is left between them. A consider- able interval exists between the cranium and atlas, and another between the last lumbar vertebra and sacrum. The spinous processes are horizontal in the cervical, and become gradu- ally oblique in the upper part of the dorsal region. In the middle of the dorsal region they are nearly vertical and imbricated, and towards its lower part assume the direction of the lumbar spines, winch are quite horizontal. The transverse processes developed in their most rudimentary form in the axis, gradually increase in length to the first dorsal vertebra. In the dorsal region they project obliquely backwards, and diminish sud- denly in length in the eleventh and twelfth vertebrae where they are very small. In the lumbar region they increase to the middle transverse pro- cess, and again subside in length to the last. The transverse processes consist essentially of two parts, the anterior of which in the dorsal region is the rib, while the posterior retains the name of the transverse process. In the cervical region these two elements are quite apparent, both by their different points of attachment to the ver- tebra, and by the vertebral foramen which divides them at their base. In the lumbar region the so-called transverse processes are in reality lumbar ribs, while the transverse processes will be found behind them in a rudi- mentary state, developed, like the true transverse processes in the cervical region, from the superior articular processes. When the anterior and posterior transverse processes are examined in relation with each other, they,will be observed to converge; if they were prolonged they would unite as in the cervical region and enclose a foramen, or they would rest in contact as in the dorsal region, or become consolidated as in the form- ation of the sacrum. Moreover, the posterior transverse processes are DEVELOPMENT OF VERTEBRAE. 55 directed upwards, and if they were prolonged, they would come into con- tact with a small tubercle which is found at the base of the posterior trans- verse process (in strongly-marked vertebrae) in the vertebra above. This junction would form a posterior intervertebral foramen, as actually occurs in the sacrum. In brief, the lumbar vertebrae exhibit those transitional changes which are calculated, by an easy gradation, to convert separate vertebrae into a solid bone. The transverse processes of the eleventh and twelfth dorsal vertebrae are very interesting in a transcendental point of view, as exhibiting a tendency which exists obscurely in all the rest, namely, to trifurcate. Now, supposing these three branches to be length- ened in order to fulfil their purposes, the anterior would constitute the articulation or union with a rib, while the superior and inferior would join similar branches in the vertebra above and below, and so form the poste- rior intervertebral foramen. The intervertebral foramina formed by the juxtaposition of the notches are smallest in the cervical region, and gradually increase to the last lum- bar. On either side of the spinous processes, and extending the whole length of the column, is the vertebral groove, which is shallow and broad in the cervical, and deeper and narrower in the dorsal and lumbar regions. It lodges the principal muscles of the back. Viewed from the side, the vertebral column presents several curves, the principal of which is situated in the dorsal region, the concavity looking forwards. In the cervical and lumbar regions the column is convex in front; and in the pelvis an anterior concave curve is formed by the sacrum and coccyx. Besides the antero-posterior curves, a slight lateral curve exists in the dorsal region, having its convexity towards the right side. Development.—The vertebras are developed by three primary and five secondary centres or epiphyses. The primary centres are, one for each lamella, and one for the body; the epiphyses, one for the apex of the spinous process, one for that of each transverse process, and one for the upper and under surface of the body. Exceptions to this mode of deve- lopment are met with in the atlas, axis, vertebra prominens, and lumbar vertebras. The atlas has four centres: one for each lateral mass, one (sometimes two) for the anterior arch, and one for the centre of the poste- rior arch. The axis has five: one (sometimes two) for the body, two for the odontoid process, appearing side by side in its base, and one for each lamella. The vertebra prominens has two additional centres for the ante- rior or costal segments of the transverse processes, and the lumbar vertebra two for the posterior segments of the transverse processes. The primary centres of the vertebrae make their appearance during the seventh or eighth week of embryonic existence, the lamella being some- what in advance of that for the body. From the former are produced the spinous, transverse, and articular processes, and the sides of the body; they unite, to complete the arch, one year after birth, and with the body during the fifth year. The epiphyses, for the extremities of the spinous and transverse processes, make their appearance at fifteen or sixteen, and become united between twenty and twenty-five. The epiphyses of the body are somewhat later in appearance, and are consolidated between the periods of twenty-five and thirty years of age. The ossific centres for the lateral masses of the atlas appear at the same time with those of the other vertebrae; they unite posteriorly at the end of the second year, by the intervention of the centre for the posterior arch. 56 SACRUM. The one or two centres of the anterior arch appear during the first year, and become consolidated with the lateral pieces during the fifth or sixth year. The axis develops its lateral pieces at the same time with the rest of the vertebrae ; they join posteriorly soon after birth, and with the body during the fourth or fifth year. The centres for the body and odontoid process appear during the sixth month, and are consolidated during the third year. The body of the axis is more largely developed at birth than that of the other vertebrae. The costal segments of the vertebra prominens appear during the second month, and become united to the body at the fifth or sixth year. These processes sometimes remain permanently sepa- rate, and constitute a cervical rib. The transverse process of the first lumbar vertebra has sometimes a distinct centre, which may remain per- manently separate, in that case forming a lumbar rib. The ossification of the arches of the vertebrae commences from above, and proceeds gradually downwards; hence arrest of development gives ' rise to spina bifida, generally in the loins. Ossification of the bodies, on the contrary, commences from the centre, and proceeds from that point towards the extremities of the column; hence imperfection of the bodies occurs either in the upper or lower vertebrae. Attachment of Muscles.—To the atlas are attached ten pairs of muscles; the longus colli, rectus anticus minor, rectus lateralis, rectus posticus minor, obliquus superior and inferior, splenius colli, levator anguli scapulae, first interspinales, and first intertransversales. To the axis are attached twelve pairs, viz.: the longus colli, intertrans- versales, obliquus inferior, rectus posticus major, supraspinalis, interspi- nales, semi-spinalis colli, multifidus spinae, levator anguli scapulae, splenius colli, transversalis colli, and scalenus posticus. To the remaining vertebra collectively, thirty-three pairs;—viz. poste- riorly, the trapezius, latissimus dorsi, levator anguli scapulae, rhomboideus minor and major, serratus posticus superior and inferior, splenius, sacro- lumbalis, longissimus dorsi, spinalis dorsi, cervicalis ascendens, trans- versalis colli, trachelo-mastoideus, complexus, semi-spinalis dorsi and colli, multifidus spinae, supraspinalis, interspinales, intertransversales, levatores costarum: anteriorly, the rectus anticus major, longus colli, scalenus anticus and posticus, psoas magnus, psoas parvus, quadratus lumborum, diaphragm, obliquus internus and transversalis. The Sacrum is a triangular bone, situated at the lower extremity of the vertebral column, and formed by the consolidation of five false vertebrae. It is divisible into an anterior and posterior surface, two lateral and a superior border, and an inferior extremity. The anterior surface is concave, and marked by four transverse lines, which indicate its original constitution of five separate pieces. At the extremities of these lines, on each side, are the four anterior sacral fora- mina, which diminish in size from above downwards, and transmit the anterior sacral nerves. The projection of the superior piece is the sacro- vertebral angle or promontory. The posterior surface is narrower than the anterior and convex. Upon the middle line is a rough crest formed by the rudiments of four spinous processes, the fifth remaining undeveloped and exposing the lower termi- nation of the sacral canal. Immediately external to and parallel with the median crest, is a range of five small tubercles which represent the poste- SACRUM. 57 rior transverse processes of the true vertebrae; beyond these is a shallow groove in which the four posterior sacral foramina open, and farther out- wards, a range of five tubercles corresponding with the anterior or costal transverse processes of the lumbar vertebrae. The lowest pair of the pos- terior transverse tubercles bound on each side the termination of the sacral canal, and send each a process downwards to articulate with the coccyx. The two descending processes are the sacral cornua. The posterior sacral foramina are smaller than the anterior, and transmit the posterior sacral nerves. Of the anterior transverse tubercles the first corresponds with the angle of the superior border of the bone; the second is small, and enters into the formation of the sacro-iliac articulation ; the third is large, and gives attachment to the oblique sacro-iliac ligament; the fourth and fifth are smaller, and serve for the attachment of the sacro-ischiatic ligaments. The lateral border of the sacrum presents superiorly a broad and ear-shaped (auricular) surface to articulate with the ilium; and inferiorly a sharp edge, to which the greater and lesser sacro-ischiatic ligaments are attached. On the superior border, in the middle line, is an oval articular surface, which corresponds with the under part of the body of the last lumbar vertebra; and on each side a broad triangular surface, which supports the lumbo-sacral nerve and psoas magnus muscle. Immediately behind the vertebral articular sur- face is the triangular entrance of the sacral canal; and on each side of this opening an articular process, which looks backwards and inwards, like the superior articular processes of the lumbar vertebrae. In front of each articular process is an intervertebral notch. The inferior extremity of the bone presents a small oval surface which articulates with the coccyx; and on each side a notch, which, with a corresponding notch in the upper border of the coccyx, forms the foramen for the transmission of the fifth sacral nerve. The sacrum presents some variety in respect of curvature, and of the number of pieces which enter into its structure. The curve is often very slight, and is situated only near the lower part of the bone; while in other subjects it is considerable, and occurs at the middle of the sacrum. The sexual differences in the sacrum relate to its greater breadth, and the greater angle which it forms with the rest of the vertebral column in the female, rather than to any peculiarity in shape. It is sometimes composed of six pieces, more rarely of four, and, occasionally, the first and second pieces remain permanently separate. Development.—By twenty-one points of ossification; five for each of the three first pieces, viz. one for the body, one for each lateral portion, and one for each lamina; and three for each of the two last, namely, one for * The sacrum seen upon its anterior surface. 1, 1. The transverse lines marking the original constitution of the bone of four pieces. 2, 2. The anterior sacral foramina. 3. The promontory of the sacrum. 4. The ear-shaped surface which articulates with the ilium. 5. The sharp edge to which the sacro-ischiatic ligaments are attached 6. The vertebral articular surface. 7. The broad triangular surface which supports the psoas muscle and lumbo-sacral nerve. 8. The articular process of the right side. 9. The inferior extremity, or apex of the sacrum. 10. One of the sacral cornua. 11. The notch which is converted into a foramen by the coccyx. 58 . coccyx. the body, and one for each lateral portion. In the progress of growth, and after puberty, fourteen epiphysal centres are added, namely, two for the surfaces of each body, one for each auricular surface, and one for the thin edge of each lateral border. Ossification begins in the bodies of the sacral pieces'somewhat later than in those of the true vertebrae; the first three appearing during the eighth and ninth week, and the last two at about the middle of the intra-uterine existence. Ossification of the lamellae takes place during the interval between the sixth and the ninth month. The epiphyses for the upper and under surface of the bodies are developed during the interval between the fifteenth and eighteenth year; and for the auricular and marginal piece, after twenty. The two lower vertebral pieces, although the last to appear, are the first to be completed (between the fourth and fifth year), and to unite by their bodies. The union of the bodies takes place from below upwards, and finishes between the twenty- fifth and the thirtieth year, with the first two pieces. Articulations.—With four bones; the last lumbar vertebra, ossa inno- minate, and coccyx. Attachment of Muscles.—To seven pairs; in front the pyriformis, on the side the coccygeus, and behind the gluteus maximus, latissimus dorsi, longissimus dorsi, sacro-lumbalis, and multifidus spinae. The Coccyx (xoxxug cuckoo, from resembling a cuckoo's beak) is com- posed of four small pieces, which form the caudal termination of the ver- tebral column. The superior piece is broad, and expands laterally into two transverse processes; it is surmounted by an oval articular surface and two cornua, the former to articulate with the apex of the sacrum, and the latter with the sacral cornua. The lateral wings sometimes become connected with the sacrum, and convert the notches for the fifth pair of sacral nerves into foramina. The remaining three pieces diminish in size from above downwards. Development.—By four centres; one for each piece. Ossification com- mences in the first piece soon after birth; in the second, between five and ten years; in the third, between ten and fifteen; and in the fourth, be- tween fifteen and twenty. The pieces unite at an earlier period than the bodies of the sacrum, the first two pieces first, then the third and fourth, and lastly, the second and third. Between forty and sixty years, the coccyx becomes consolidated with the sacrum; this event taking place later in the femare than in the male. Articulations.—With the sacrum. Attachment of Muscles.—To three pairs, and one single muscle; gluteus maximus, coccygeus, posterior fibres of the levator ani, and sphincter ani. % OF THE SKULL. The skull, or superior expansion of the vertebral column, is divisible into tw^o parts,—the cranium and the face; the former being adapted, by its form, structure, and strength, to contain and protect the brain, and the latter the chief organs of sense. The Cranium is composed of eight separate bones; viz., the Occipital, Two temporal, Two parietal, Sphenoid, Frontal, Ethmoid. OCCIPITAL BONE. 59 Occipital Bone.—This bone is situated at the posterior part and base of the cranium. It is trapezoid in figure, and divisible into two surfaces, four borders, and four angles. External Surface.—Crossing the middle of the bone transversely, from one lateral angle to the other, is a prominent ridge, the superior curved line. In the middle of the ridge is a projection, called the external occipital Fig. 22* protuberance; and descending from it a small vertical ridge, the spine. Above and below the superior curved line the surface is rough, for the attachment of muscles. About three-quarters of an inch below this line is another trans- verse ridge, the inferior curved line, and beneath the latter the foramen mag- num. On each side of the foramen magnum, nearer to its anterior than its posterior segment, and encroaching somewhat upon the opening, is an ob- long articular surface, the condyle, for articulation with the atlas. The con- dyles approach towards each other an- teriorly, and their articular surfaces look downwards and outwards. Directly behind each condyle is an irregular fossa, and a small opening, the posterior condyloid foramen, for the transmission of a vein to the lateral sinus. In front of the condyle is the anterior condyloid foramen, for the hypoglossal nerve; and on the outer side of each condyle a projecting ridge, the transverse process, excavated in front by a notch which forms part of the jugular foramen. In front of the foramen magnum is a thick square mass, the basilar process, and in the centre of the basilar process a small tubercle for the attachment of the superior and middle constrictor muscles of the pharynx. Internal Surface. — Upon the internal surface is a crucial ridge, which divides the bone into four fossae; the two superior or cerebral fossae lodging the posterior lobes of the cerebrum; and the two inferior or cerebellar, the lateral lobes of the cerebellum. The superior arm of the crucial ridge is grooved for the superior longitudinal sinus, and gives attachment to the falx cerebri; the inferior arm is sharp and prominent, for the attachment of the falx cerebelli, and slightly grooved for the two occipital sinuses. The transverse ridge gives attachment to the tentorium cerebelli, and is deeply grooved for the lateral sinuses. At the point of meeting of the four arms is a projection, the internal occipital protuberance, which corre-, sponds with the similar process situated upon the external surface of the bone. The convergence of the four grooves forrns a slightly depressed fossa, upon which rests the torcular Herophili. In the centre of the * The external surface of the occipital bone. 1. The superior curved line. 2. The external occipital protuberance. 3. The spine. 4. The inferior curved line. 5. The foramen magnum. 6. The condyle of the right side. 7. The posterior condyloid fossa, in which the posterior condyloid foramen is found. 8. The anterior condyloid foramen, concealed by the margin of the condyle. 9. The transverse process; this process upon the internal surface of the bone forms the jugular eminence. 10.- The notch in front of the jugular eminence which forms part of the jugular foramen. 11. The basilar process 12, 12. Tin- rough projections into which the odontoid ligaments are inserted. 60 OCCIPITAL BONE. 23.* basilar portion of the bone is the foramen magnum, oblong in form, and larger behind than before, transmitting the spinal cord, spinal accessory nerves, and vertebral arteries. Upon the lateral margins of the foramen magnum are two rough eminences, which give attachment to the odon- toid ligaments, and immediately above these the openings of the anterior con- dyloid foramina. In front of the fora- men magnum is the basilar process, grooved on its surface, for supporting f^ the medulla oblongata, and along each lateral border, for the inferior petrosal sinuses. On each side of the foramen magnum is a groove, for the termina- tion of the lateral sinus; a smooth sur- face, which forms part of the jugular fossa; and a projecting process, which divides the two, and is called the jugular eminence. Into the jugular fossa will be seen opening the posterior condyloid foramen. The superior borders are very much serrated, and assist in forming the lambdoidal suture; the inferior are rough, but not serrated, and articulate with the mastoid portion of the temporal bone by means 0/ the addita- mentum suturae lambdoidalis. The jugular eminence and the side of the basilar process articulate with the petrous portion of the temporal bone, and the intermediate space, which is irregularly notched, forms the poste- rior boundary of the jugular foramen, or foramen lacerum posterius. The angles of the occipital bone are the superior, inferior, and two lateral. The superior angle is received into the interval formed by the union of the posterior and superior angles of the parietal bones, and cor- responds with that portion of the foetal head which is called the posterior fontanelle. The inferior angle is the articular extremity of the basilar process. The lateral angles at each side project into that interval formed by the articulation of the posterior and inferior angle of the parietal with the mastoid portion of the temporal bone. Development.—By seven centres ; four for the four parts of the expanded portion divided by the crucial ridge, one for each condyle, and one for the basilar process. Ossification commences in the expanded portion of the bone at a period anterior to the vertebrae ; at birth the four remaining pieces are distinct; they are united at about the fifth or sixth year. After twenty the basilar process unites with the body of the sphenoid. *The internal surface of the occipital bone. 1. The left cerebral fossa. 2. The left cerebellar fossa. 3. The groove for the posterior part of the superior longitudinal sinus 4. The spine for the falx cerebelli, and groove for the occipital sinuses. 5 The groove for the left lateral sinus. 6. The internal occipital protuberance, the groove on which lodges the torcular Herophili. 7. The foramen magnum. 8. The basilar process grooved for the medulla oblongata. 9. The termination of the groove for the lateral sinus, bounded externally by the jugular eminence. 10. The jugular fossa- this fossa is completed by the petrous portion of the temporal bone. 11. The superior border 12. The inferior border. 13. The border which articulates with the petrous portion of the temporal bone, and which is grooved by the inferior petrosal sinus. 14 The ante rior condyloid foramen. PARIETAL BONE. 61 Articulations.—With six bones; two parietal, two temporal, sphenoid and atlas. Attachment of Muscles.—To thirteen pairs: to the rough surface above the superior curved line, the occipito-frontalis; to the superior curved line, the trapezius and sterno-mastoid; to the rough space between the curved lines, complexus, and splenius capitis; to the space between the inferior curved line and the foramen magnum, the rectus posticus major and minor, and obliquus superior; to the transverse process, the rectus lateralis ; and to the basilar process, the rectus anticus major and minor, and superior and middle constrictor muscles. Parietal Bone. — The parietal Fig 24 * bone is situated at the side and ver- tex of the skull; it is quadrilateral in form, and divisible into an external and internal surface, four borders and four angles. The superior border is straight, to articulate with its fellow of the opposite side. The inferior border is arched and thin, to articu- late with the temporal bone. The anterior border is concave, and the posterior somewhat convex. External surface. — Crossing the bone in a longitudinal direction from the anterior to the posterior border, is an arched line, the temporal ridge, to which the temporal fascia is attached. In the middle of this line, and nearly in the centre of the bone, is the projection called the parietal emi- nence, which marks the centre of ossification. Above the temporal ridge the surface is rough, and covered by the aponeurosis of the occipito-fron- talis ; below the ridge the bone is smooth (planum semicirculare), for the attachment of the fleshy fibres of the temporal muscle. Near the superior border of the bone, and at about one-third from its posterior extremity, is the parietal foramen, which transmits a vein to the superior longitudinal sinus. This foramen is often absent. Internal surface.—The internal table is smooth; it is marked by nu- merous furrows, which lodge the ramifications of the arteria meningea media, and by digital fossae which correspond with the convolutions of the brain. Along the upper border is part of a shallow groove, completed by the opposite parietal bone, which serves to contain the superior longitu- dinal sinus. Some slight pits are also observable near this groove, which lodge the glandulae Pacchioni. The anterior inferior angle is thin and lengthened, and articulates with the greater wing of the sphenoid bone. Upon its inner surface it is deeply channelled by a groove for the trunk of the arteria meningea media. This groove is frequently converted into a canal. The posterior * The external surface of the left parietal bone. 1. The superior or sagittal border. 2. The inferior or squamous border. 3. The anterior or coronal border. 4. The poste- rior or lambdoidal border. 5. The temporal ridge; the figure is situated immediately in front of the parietal eminence. 6. The parietal foramen, unusually large in the bone from which this figure was drawn. 7. The anterior inferior angle. 8. The posterior inferior angle. 6 62 FRONTAL BONE. Fig.25* inferior angle is thick, and presents a broad and shallow groove for the lateral sinus. Development.—By a single centre. Ossification commences at the parie- tal eminence at the same time with the bodies of the vertebrae. Articulations. — With five bones; with the opposite parietal bone, the occipital, frontal, temporal, and sphe- noid. Attachment of Muscles. — To one only,—the temporal. The occipito- frontalis glides over its upper sur- 7 face. Frontal Bone.—The frontal bone bears some resemblance in form to the under valve of a scallop shell. It is situated at the anterior part of the cranium, forming the forehead, and assists in the construction of the roof of the orbits and nose. Hence it is divisible into a superior or frontal portion, and an inferior or orbito-nasal portion. Each of these portions presents for examination an external and internal surface, borders, and processes. External surface.—At about the middle of each lateral half of the fron- tal oortion is a projection, the frontal eminence. Below these points are tht ■"verciliary ridges, large towards their inner termination, and becoming gra lay smaller as they arch outwards : they support the eyebrows. BeiK h the superciliary ridges are the sharp and prominent arches which form le upper margin of the orbits, the supra-orbital ridges. Externally the supra-orbital ridge terminates in the external angular process, and inten. illy in the in ernal angular process; at the inner third of this ridge is a notch, sometimes converted into a foramen, the supra-orbital notch, which gives passage to the supra-orbital artery, veins, and nerve. Be- tween the two superciliary ridges is a rough projection, the nasal tuberosi- ty ; this portion of the bone denotes by its prominence the situation of the frontal sinuses. Extending upwards and backwards from the-external angular process is a sharp ridge, the commencement of the temporal ridge, and beneath this a depressed surface that forms part of the temporal fossa. The orbito-nasal portion of the bone consists of two thin processes, the orbital plates, which form the roof of the orbits, and of an intervening notch which lodges the ethmoid bone, and is called the ethmoidal fissure. The edges of the ethmoidal fissure are hollowed into cavities, which, by their union with the ethmoid bone, complete the ethmoidal cells: and, crossing these edges transversely, are two small grooves, sometimes canals, which open into the orbit by the anterior and posterior ethmoidal foramina. At the anterior termination of these edges are the irregular openings which * The internal surface of the left parietal bone. 1. The superior or sagittal border. 2. The inferior, or squamous border. 3. The anterior, or coronal border. 4. The poste- rior, or lambdoidal border. 5. Part of the groove for the superior longitudinal sinus. 6. The internal termination of the parietal foramen. 7. The anterior inferior angle of the bone, on which is seen the groove for the trunk of the arteria meningea media. 8 The posterior inferior angle, upon which is seen a portion of the groove for the latera, sinus. FRONTAL BONE. 63 Fig. 26* lead into the frontal sinuses; and between the two internal angular pro- cesses, is a rough excavation which receives the nasal bones, and a pro- jecting process, the nasal spine. Upon each orbital plate, immediately beneath the external angular process, is a shallow depression which lodges the lachrymal gland; and beneath the internal angular process a small pit, sometimes a tubercle, to which the cartilaginous pulley of the superior oblique muscle is attached. Internal Surface.—Along the mid- dle line of this surface is a grooved ridge, the edges of the ridge giving attachment to the falx cerebri and the groove lodging the superior longitu- dinal sinus. At the commencement of the ridge is an opening, sometimes completed by the ethmoid bone, the foramen cacum. This opening lodges a process of the dura mater, and oc- casionally gives passage to a small vein which communicates with the nasal veins. On each side of the vertical ridge are some slight depres- sions which lodge the glandulae Pacchioni, and on the orbital plates a number of irregular pits called digital fossa, which correspond with the convolutions of the anterior lobes of the cerebrum. is thick and strongly serrated, bevelled at the expense of the internal table in the middle, where it rests upon the junction of the two parietal, and at the expense of the external table on each side where it receives the lateral pres- sure of those bones. The inferior bor- der is thin, irregular, and squamous, and articulates with the sphenoid bone. Development.—By two centres, one for each lateral half. Ossification be- gins in the orbital arches, somewhat before the vertebrae. The two pieces are separate at birth, and unite by su- ture during the first year, the su- ture sometimes remaining permanent * The external surface of the frontal bone. 1. The situation of the frontal eminence of the right side. 2. The superciliary ridge. 3. The supra-orbital ridge. 4. The ex- ternal angular process. 5. The internal angular process. 6. The supra-orbital notch for the transmission of the supra-orbital nerve and artery; in the figure it is almost converted into a foramen by a small spiculum of bone. 7. The nasal tuberosity; the swelling around this point denotes the situation of the frontal sinuses. 8. The temporal ridge, commencing from the external angular process (4). The depression in which the figure S is situated is a part of the temporal fossa. 9. The nasal spine. + The internal surface of the frontal bone; the bone is raised in such a manner as to show the orbito-nasal portion. 1. The grooved ridge for the lodgment of the superior longitudinal sinus and attachment of the falx. 2. The foramen CEECum. 3. The superior The superior bor r Fig.27.f -i' 64 TEMPORAL BONE. through life. The frontal sinuses make their appearance during the first year, and increase in size until old age. Articulations.—-With twelve bones: the two parietal, the sphenoid, ethmoid, two nasal, two superior maxillary, two lachrymal, and two malar. Attachment of Muscles.—To two pairs: corrugator supercilii, and tem- poral. Temporal Bone.—The temporal bone is situated at the side and base of the skull, and is divisible into a squamous, mastoid, and petrous portion. The Squamous portion, forming the anterior part of the bone, is thin, translucent, and contains no diploe. Upon its external surface it is smooth, to give attachment to the fleshy fibres of the temporal muscle, and has projecting from it an arched Fis- 28- and lengthened process, the zygoma. Near the commencement of the zygo- ma, upon its lowrer border, is a projec- tion called the tubercle, to whiclj is at- tached the external lateral ligament of the lower jaw, and continued horizon- tally inwards from the tubercle, a rounded eminence, the eminentia arti- cularis. The process of bone which is continued from the tubercle of the zygoma into the eminentia articularis is the inferior root of the zygoma. The superior root is continued upwards from the upper border of the zygoma, and forms the posterior part of the temporal ridge, serving.by its projec- tion to mark the division of the squamous from the mastoid portion of the bone; and the middle root is continued directly backwards, and termi- nates abruptly at a narrow fissure, the fissura Glaseri. The internal sur- face of the squamous portion is marked by several shallow fossae, which correspond with the convolutions of the cerebrum, and by a furrow for or coronal border of the bone; the figure is situated near that part which is bevelled at the expense of the internal table. 4. The inferior border of the bone. 5. The orbital plate of the left side. 6. The cellular border of the ethmoidal fissure. The foramen caecum (2) is seen through the ethmoidal fissure. 7. The anterior and posterior eth- moidal foramina; the anterior is seen leading into its canal. 8. The nasal spine. 9. The depression within the external angular process (12) for the lachrymal gland. 10. The depression for the pulley of the superior oblique muscle of the eye; immediately to the left of this number is the supra-orbital notch, and to its right the internal angular process. 11. The opening leading into the frontal sinuses: the leading line crosses the internal angular process. 12. The external angular process. The corresponding parts are seen on the other side of the figure. * The external surface of the temporal bone of the left side. 1. The squamous por- tion. 2. The mastoid portion. 3. The extremity of the petrous portion. 4. The zy- goma. 5. Indicates the tubercle of the zygoma, and at the same time its anterior root turning inwards to form the eminentia articularis. 6. The superior root of the zygoma, forming the posterior part of the temporal ridge. 7. The middle root of the zygoma, terminating abruptly at the glenoid fissure. 8. The mastoid foramen. 9. The meatus auditorius externus, surrounded by the processus auditorius. 10. The digastric fossa, situated immediately to the inner side of (2) the mastoid process. 11. The styloid process. 12. The vaginal process. 13. The glenoid or Glaserian fissure; the leading line from this number crosses the rough posterior portion of the glenoid fossa. 14. The opening and part of the groove for the Eustachian tube. TEMPORAL BONE. 65 the posterior branch of the arteria meningea media. The superior, or squamous border, is very thin, and bevelled at the expense of the inner surface, so as to overlap the lower and arched border of the parietal bone. The inferior border is thick, and dentated to articulate with the spinous process of the sphenoid bone. The Mastoid portion forms the posterior part of the bone ; it is thick, and hollowed between its tables into a loose and cellular diploe. Upon its external surface it is rough for the attachment of muscles, and contrasts strongly with the smooth and polished-like surface of the squamous por- tion : every part of this surface is pierced by small foramina, which give passage to minute arteries and veins; one of these openings, oblique in its direction, of large size, and situated near the posterior border of the bone, the mastoid foramen, transmits a vein to the lateral sinus. This foramen is not unfrequently situated in the occipital bone. The inferior part of this portion is round and expanded, the mastoid process, and ex- cavated in its interior into numerous cells, which form a part of the organ of hearing. In front of the mastoid process, and between the superior and middle roots of the zygoma, is the large oval opening of the 'meatus auditorius externus, surrounded by a rough lip, the processus auditorius. Directly to the inner side of, and partly concealed by the mastoid process, is a deep groove, the digastric fossa; and a little more internally the oc- cipital groove, which lodges the occipital artery. Upon its internal sur- face the mastoid portion presents a broad and shallow groove (fossa sig- moidea) for the lateral sinus, and terminating in this groove the internal opening of the mastoid foramen. The superior border of the mastoid por- tion is dentated ; and its posterior border, thick and less serrated, articu- lates with the inferior border of the occipital bone. The meatus auditonus externus is a slightly curved canal, somewhat more than half an inch in length, longer along its lower than its upper wall, and directed obliquely inwards and forwards. The canal is narrower at the middle than at each extremity, is broadest in its horizontal diameter, and terminates upon the outer wall of the tympanum by an abrupt oval border. Within the margin of this border is a groove for the insertion of the membrana tympani. The Petrous portion of the temporal bone is named from its extreme hardness and density. It is a three-sided pyramid, projecting horizontally forwards into the base* of the skull, the base being applied against the in- ternal surface of the squamous and mastoid portions, and the apex being received into the triangular interval between the spinous process of the sphenoid and the basilar process of the occipital bone. For convenience of description it is divisible into three surfaces—anterior, posterior, and basilar ; and three borders—superior, anterior, and posterior. Surfaces.—The anterior surface, forming the posterior boundary of the middle fossa of the interior of the base of the skull, presents for exami- nation from base to apex, first, an eminence caused by the projection of the perpendicular semicircular canal; next, a groove leading to an irregular oblique opening, "the hiatus Fallopii, for the transmission of the petrosal branchWthe Vidian nerve; thirdly, another and smaller oblique foramen, immediately beneath the preceding, for the passage of the nervus petrosus superficialis minor, a branch of Jacobson's nerve; and, lastly, a large foramen near the apex of the bone, the termination of the carotid canal. 6* E 66 TEMPORAL BONE. The posterior surface forms the front boundary of the posterior fossa of the base of the skull; near its middle is the oblique entrance of the meatus auditorius internus. Above the meatus Fis; 29* auditorius internus is a small oblique fis- 4^7^i)r"t sure> anc* a mmute forarnen ; the former lodges a process of the dura mater, and the foramen gives passage to a small vein. Further outwards, towards the mastoid portion of the bone, is a small slit, almost hidden by a thin plate of bone; this is the aquaductus vestibuli, and transmits a small artery and vein of the vestibule and a process of dura mater. Below the meatus, and partly concealed by the margin of the posterior border of the bone, is the aquaductus cochlea, through which passes a vein from the cochlea to the internal jugular vein, and a process of dura mater. The meatus auditorius internus is about one-third of an inch in depth, and pursues a slightly oblique course in relation to the petrous portion of the temporal bone, but a course directly out- wards in relation to the cranium. At the bot- tom of the meatus, and upon its anterior as- pect, is a reniform fossa, the concave border of which is directed towards the entrance of the meatus. The reniform fossa is divided into an upper and lower compartment by a sharp ridge, which is prolonged for some dis- tance upon the anterior wall of the meatus, and sometimes as far as its aperture; in either case it marks the situation of the two nerves, facial and auditory, which constitute the se- venth pair, and enter the meatus. Along the convexity of the reniform fossa, and arranged in a curved line from above downwards, are four or * The left temporal bone, seen from within. 1. The squamous portion. 2. The mastoid portion. The number is placed immediately above the inner opening of the mastoid foramen. 3. The petrous portion. 4. The groove for the posterior branch of the arteria meningea media. 5. The bevelled edge of the squamous border of the bone. 6. The zygoma. 7. The digastric fossa immediately internal to the mastoid process 8. The occipital groove. 9. The groove for the lateral sinus. 10. The elevation upon the anterior surface of the petrous bone marking the situation of the perpendicular semi- circular canal. 11. The opening of termination of the carotid canal. 12. The meatus auditorius internus. 13. A dotted line leads upwards from this number to the narrow fissure which lodges a process of the dura mater. Another line leads downwards to the sharp edge which conceals the opening of the aquseductus cochlese, while the num- ber itself is situated on the bony lamina which overlies the opening of the aqugeductus vestibuli. 14. The styloid process. 15. The stylo-mastoid foramen. 16. The carotid foramen. 17. The jugular process. The deep excavation to the left of this process forms part of the jugular fossa, and that to the right is the groove for the eighth pair of nerves. 18. The notch for the fifth nerve upon the upper border of the petrous bone, near its apex. 19. The extremity of the petrous bone which gives origin to the levator palati and tensor tympani muscles. |a. The reniform fossa of the meatus auditorius internus; right temporal bone. 1. The ridge dividing the reniform fossa into two compartments. 2. The opening of the aquseductus Fallopii. The openings following that of the aquseductus Fallopli in a curved direction require no reference. 3. The cluster of three or four oblique TEMPORAL BONE. 67 five openings, the two upper ones being the largest, and occupying the superior compartment of the reniform fossa, and the two or three inferior ones, smaller than the upper, the inferior compartment. Behind the latter, at the distance of a line and a half, and on the posterior wall of the meatus, is a cluster of three or four oblique openings, two of which are minute. The inferior and larger compartment of the reniform fossa pre- sents a well-marked spiral groove, which commences on the convex border of the fossa, immediately below the line of openings above described, and, sweeping round the convexity of the inferior compartment, and becoming deeper as it proceeds, terminates by a small round aperture in the centre of the spire. The uppermost of the openings of the reniform fossa is the aperture of the aquseductus Fallopii, and gives passage to the facial nerve. The rest are cul de sacs, pierced at the bottom by a number of minute foramina for the passage of filaments of the vestibular nerve, while the cluster of three openings on the posterior wall of the meatus are intended for single filaments of the same nerve. The spiral groove corresponds with the base of the cochlea, and being pierced by a number of minute foramina for filaments of the cochlear nerve, is named tractus spiralis foraminulentus. The opening in the centre of the spiral impression leads into a canal which occupies the central axis of the modiolus, and is thence called tubulus centralis modioli. The basilar surface is rough and irregular, and enters into the formation of the under surface of the base of the skull. Projecting downwards, near its middle, is a long sharp spine, the styloid process, occasionally connected with the bone only by cartilage, and lost during maceration, particularly in the young subject. At the base of this process is a rough sheafh-like ridge, into which the styloid process appears implanted, the vaginal pro- cess. In front of the vaginal process is a broad triangular depression, the glenoid fossa, bounded in front by the eminentia articularis, behind by the vaginal process, and externally by the rough lip of the processus audi- torius. This fossa is divided transversely by the glenoid fissure (fissura Glaseri), which lodges the extremity of the processus gracilis of the malleus, and transmits the laxator tympani muscle, chorda tympani nerve, and anterior tympanic artery. The surface of the fossa in front of this fissure is smooth, to articulate with the condyle of the lower jaw ; and that behind the fissure is rough, for the reception of a part of the parotid gland. At the extre- mity of the inner angle of the glenoid fossa is the foramen of the Eusta- chian tube; and separated from it by a thin lamella of bone, called pro- cessus cochleariformis, a small canal for the transmission of the tensor tympani muscle. Directly behind, and at the root of the styloid process, is the stylo-mastoid foramen, the opening of exit of the facial nerve, and of entrance of the stylo-mastoid artery. Nearer the apex of the bone is a openings on the posterior wall of the meatus. 4. The spirally-grooved base of the cochlea. b. A section of the temporal bone, right side, showing the curved direction of the meatus auditorius externus. 1. The edge of the processus auditorius. 2. The groove into which the membrana tympani is inserted. The obliquity of the line from 2 to 3 indicates the oblique termination of the meatus, and the consequent oblique direction of the membrana tympani. 4, 4. The cavity of the tympanum. 5. The opening of the Eustachian tube. 6. Part of the aqua'ductus Fallopii. 7. Part of the carotid canal. C. The annulus membranae tympani or temporal bone of the fcetal skull, right side. 68 TEMPORAL BONE. large oval opening, the carotid foramen, the commencement of the carotid canal, which lodges the internal carotid artery and the carotid plexus. And between the stylo-mastoid and carotid 'foramen, in the posterior border, is an irregular excavation forming part of the jugular fossa for the commencement of the internal jugular vein. The proportion of the jugular fossa formed by the petrous portion of the temporal bone is very different in different bones; but in all, the fossa presents a vertical ridge on its inner side, which cuts off a small portion from the rest. The upper part of this ridge forms a spinous projection, which is called the jugular process, the groove to the inner side of the ridge lodges the eighth pair of nerves, and the lower part of the ridge is the septum of division between the jugu- lar fossa and the carotid foramen. Upon this portion of the ridge near the posterior margin of the carotid foramen is a small opening leading into a canal, which transmits the tympanic branch (Jacobson's nerve) of the glossopharyngeal nerve. Between the jugular fossa and the stylo-mastoid foramen is another small opening leading into the canal for the passage of the auricular branch of the pneumogastric nerve. Borders. — The superior border is sharp, and gives attachment to the tentorium cerebelli. It is grooved for the superior petrosal sinus, and near its extremity is marked by a smooth notch upon which reclines the fifth nerve. The anterior border is grooved for the Eustachian tube, and forms the posterior boundary of the foramen lacerum basis cranii; by its sharp extremity it gives attachment to the tensor tympani and levator palati muscles. The posterior border is grooved for the inferior petrosal sinus, and excavated for the jugular fossa; it forms the anterior boundary of the foramen lacerum posterius. Development. — By five centres: one for the squamous portion, one for the mastoid process, one for the petrous portion, one for the auditory pro- cess, which in the foetus is a mere bony ring, incomplete superiorly, and serving for the attachment of the membrana tympani, annulus membrana tympani; and one for the styloid process. Ossification occurs in these pieces in the following order: in the squamous portion immediately after the vertebrae, then in the petrous, tympanic, mastoid, and styloid. The tympanic ring is united by its extremities to the squamous portion during the last month of intra-uterine life ; the squamous, petrous, and mastoid portions are consolidated during the first year ; and the styloid some years after birth. It not unfrequently happens that the latter remains perma- nently separate, or is prolonged by a series of pieces to the os hyoides, and so completes the hyoid arch. • The subsequent changes in the bone are the increase of size of the glenoid fossa, the growth of the meatus auditorius externus, the levelling of the surfaces of the petrous portion, and the development of mastoid cells. Traces of the union of the petrous with the squamous portion of the bone are usually perceptible in the adult. Articulations.—With five bones : occipital, parietal, sphenoid, inferior maxillary, and malar. Attachment of Muscles.—To fourteen: by the squamous portion, to the temporal; by the zygoma, to the masseter; by the mastoid portion, to the occipito-frontalis, splenius capitis, sterno-mastoid, trachelo-mastoid, digastricus and retrahens aurem; by the styloid process, to the stylo- pharyngeus, stylo-hyoideus, stylo-glossus, and two ligaments, the stylo- SPHENOID BONE. 69 hyoid and stylo-maxillary ; and by the petrous portion, to the levator palati, tensor tympani, and stapedius. Sphenoid Bone. — The sphenoid (<7 Fig. 42.* Palate processes of superior maxillary. Palate processes of palate bone. E^h nasal fossa is divided into three irregular longitudinal passages, or meatuses, by three processes of bone, which project from its outer wall, the superior, middle, and inferior turbi- nated bones; the superior and middle turbinated bones being processes of,.the ethmoid, and the inferior a distinct bone of the face. The superior meatus occu- pies the superior and posterior part of each fossa; it is situated between the superior and middle turbinated bones, and has opening into it three foramina, viz. the opening of the posterior ethmoid cells, the opening of the sphenoid cells, and the spheno-palatine foramen. The middle meatus is the space between the middle and inferior turbinated bones; it also presents three foramina, the open- * A longitudinal section of the nasal fossae made immediately to the rignt of the middle line, and the bony septum removed in order to show the external wall of the left fossa. 1. The frontal bone. 2. The nasal bone. 3. The crista galli process of the ethmoid The groove between 1 and 3 is the lateral boundary of the foramen caecum. 4 The cribriform plate of the ethmoid. 5. Part of the sphenoidal cells. 6. The basilar portion of the sphenoid bone. Bones 2, 4, and 5, form the superior boundary of the nasal fossa 7, 7. The articulating surface ofthe palatine process ofthe superior maxil- lary bone The groove between 7, 7, is the lateral half of the incisive canal, and the dark aperture in the groove the inferior termination of the left naso-palatine canal 8 The nasal spine. 9. The palatine process of the palate bone. a. The superior tur- binated bone, marked by grooves and apertures for filaments of the olfactory nerve. b The superior meatus, c. A probe passed into the posterior ethmoidal cells, d. lhe opening of the sphenoidal cells into the superior meatus, e. The spheno-palatine fora- men f. The middle turbinated bone, g, g. The middle meatus, h. A probe passed into the infundibular canal, leading from the frontal sinuses and anterior ethmoid cells; the triangular aperture immediately above the letter is the opening of the maxillary sinus t The inferior turbinated bone, ft, ft. The inferior meatus. I, I. A prob* p-^ed up the nasal duct, showing the direction of that canal. The anterior letters''^; &'?e nlaced on the superior maxillary bone, the posterior on the palate bone. m. The in- ternal Pterygoid plate, n. Its hamular process, o. The.external pterygoid plate, p. The situation of the opening of the Eustachian tube. q. The posterior palatine foramina. r The roof of the left orbit, s. The optic foramen, f. The groove for the last turn of the internal carotid artery converted into a foramen by the development of an osseous communication between the anterior and middle clinoid processes, v. The sella turcica. t. The posterior clinoid process. 92 TEETH--CLASSIFICATION. ing ofthe frontal sinuses, ofthe anterior ethmoid cells, and ofthe antrum. The largest of the three passages is the inferior meatus, which is the space between the inferior turbinated bone and the floor of the fossa ; in it there are two foramina, the termination of the nasal duct, and one opening of the anterior palatine canal. The nasal fossae commence upon the face by a large irregular opening, the anterior nares, and terminate posteriorly in the two posterior nares. teeth. Man is provided with two successions of teeth; the first are the teeth of childhood, they are called temporary, deciduous, or milk teeth; the second continue until old age, and are named permanent. Fig. 43.* a b c d e f g h a b c d e f g h The permanent teeth are thirty-two in number, sixteen in each jaw; they are divisible into four classes, — incisors, of which there are four in each jaw, two central and two lateral; canine, two above and two below: bicuspid, four above and four below; and molars, six above and six below. The temporary teeth are twenty in number (fig. 44); eight incisors, four canine, and eight molars. The temporary molars have four tubercles, and are succeeded by the permanent bicuspides, which have only two tubercles. Each tooth is divisible into a crown, which is the part apparent above the gum; a constricted portion around the base of the crown, the neck, and a root or fang, which is contained within the alveolus. The root is invested by periosteum, which lines the alveolus, and is then reflected upon the root of the tooth as far as its neck. The incisor teeth (cutting teeth) are named from presenting a sharp and cutting edge, formed at the expense of the posterior surface. The crown is flattened from before backwards, being somewhat convex in front and concave behind ; the neck is considerably constricted, and the root com- pressed from side to side ; at its apex is a small opening for the passage of the nerve and artery of the tooth. * Permanent teeth, a. Central incisor, b. Lateral incisor, c. Cuspid or canine d. First bicuspid, e. Second bicuspid. /. First molar, g. Second molar, h. Third molar or dens sapientue. STRUCTURE OF TEETH. 03 The canine teeth (cuspidati) follow the incisors in order from before backwards; two are situated in the upper jaw, one on each side, and two in the lower. The crown is larger than that of the incisors, convex be- fore and concave behind, and tapering to a blunted point. The root is longer than that of all the other teeth, compressed at each side, and marked by a slight groove. The bicuspid teeth (bicuspidati, small molars), two on each side in each jaw, follow the canine, and are intermediate in size between them and the molars. The crown is compressed from before backwards, and sur- mounted by two tubercles, one internal, the other external; the neck is oval: the root compressed, marked on each side by a deep groove, and bifid near its apex. The teeth of the upper jaw have a greater tendency to the division of their roots than those of the lower, and the posterior than the anterior pair. The molar teeth (multicuspidati, grinders), three on each side in each jaw, are the largest of the permanent set. The crown is quadrilateral, and surmounted by four tubercles, the neck large and round, and the root divided into several fangs. In the upper jaw the first and second molar teeth have three roots, sometimes four, which are more or less widely separated from each other, two of the roots being external, the other in- ternal. In the lower there are but two roots, which are anterior and pos- terior ; they are flattened from behind forwards, and grooved so as to mark a tendency to division. The third molars, or dentes sapientiae, are smaller than the other two ; they present three tubercles on the surface of the crown; and the root is single and grooved, appearing to be made up of four or five fangs compressed together, or partially divided. In the lower jaw the fangs are frequently separated to some distance from each other, and much curved, so as to offer considerable resistance in the ope- ration of extraction, f . . Structure.—The base of the crown of each tooth is hollowed in its in- terior into a small cavity which is continuous with a canal passing through the middle of each fang. The cavity and canal, or canals, constitute the cavitas pulpae, and contain a soft cellulo-vascular organ, the pulp, which receives its supply of vessels and nerves through the small opening at the apex of each root. Mr. Nasmyth, to whose investigations science is so * Temporary teeth, a. Central incisor, b. Lateral incisor, c. Canine, d. First mo- lar, e. Second molar. , fSee an excellent practical work, " On the Structure, Economy, and Pathology of the Teeth," by Mr. Lintott. 94 STRUCTURE OF TEETH. Fig. 45* much indebted for our present knowledge of the intimate structure and development of the teeth, has observed with regard to the pulp, that it is composed of two different tissues, vascular and reticular; the former being an intricate web of minute vessels terminating in simple capillary loops, the latter a network of nucleated cells in which calcareous salts are gradually deposited, and which by a systematic continuance of that pro- cess are gradually converted into ivory. This process naturally takes place at the surface of the pulp, and as the pulp is thus robbed of its cells, new cells are produced by the capillary plexus to supply their place, and be in their turn similarly transformed. A tooth is composed of three distinct structures, ivory or tooth-bone enamel, and a cortical substance or cementum. The ivory consists of very minute, tapering, and branching fibres embedded in a dense homogene- ous, interfibrous substance. The fibres commence by their larger ends at the walls of the cavitas pulpae and pursue a radiating and serpentine course towards the periphery of the tooth, where they ter- minate in ramifications of extreme minuteness. These fibres, heretofore considered to be hollow tubuli, have been shown by Mr. Nasmyth to be rows of minute opaque bodies, arranged in a linear series (baccated fibres, Nasmyth), to be, in fact, the nuclei of the ivory cells, the interfibrous sub- stance being the rest of the cell filled with calca- reous matter. In the natural state of the tooth all trace of the parietes or mode of connexion of the cells is lost, but after steeping in weak acid the cellular network is perfectly distinct. The enamel forms a crust over the whole exposed surface of the crown of the tooth to the commencement of its root; it is thickest over the upper part of the crown, and becomes gradually thinner as it approaches the neck. It is composed of minute hexagonal crystalline fibres, resting by one extremity against the surface of the ivory, and constituting by the other the free surface of the crown. The fibres examined on the face of a longitudinal section have a waving arrangement, and consist, like those of ivory, of cells connected by their surfaces and ends and filled with cal- careous substance. When the latter is removed by weak acid, the ena- mel presents a delicate cellular net-work of animal matter. The cortical substance, or cementum, (substantia ostoidea,) forms a thin coating over the root ofthe tooth, from the termination ofthe enamel to the opening in the apex of the fang. In structure it is analogous to bone, and is characterized by the presence of numerous calcigerous cells and tubuli. The cementum increases in thickness with the advance of age, and gives rise to those exostosed appearances occasionally seen in the teeth of very old persons, or in those who have taken much mercury. In old age the cavitas pulpae is often found filled up and obliterated by * Microscopic section of a molar tooth. 1. Enamel with its columns and larr.inated structure. 2. Cortical substance or cementum on the outside of the fang. 3. Ivory, showing tubuli. 4. Foramen entering the dental cavity from the end ofthe fang. This fang has a bulbous enlargement in consequence of a. hypertrophy of the cementum. 5. Dental cavity. 6. A few osseous corpuscles in the ivory just under the enamel. DEVELOPMENT OF TEETH. 95 osseous substance analogous to the cementum. Mr. Nasmyth has shown that this, like the other structures composing a tooth, is formed of cells having a reticular arrangement. Development.—The development of the teeth in the human subject has been successfully investigated by Mr. Goodsir, to whose interesting re- searches I am indebted for the following narrative :—* The inquiries of Mr. Goodsir commenced as early as the sixth week after conception, in an embryo, which measured seven lines and a half in length and weighed fifteen grains. At this early period each upper jaw presents two semicircular folds around its circumference; the most external is the true lip ; the internal, the rudiment of the palate ; and be- tween these is a deep groove, lined by the common mucous membrane of the mouth. A little later, a ridge is developed from the floor of this groove in a direction from behind forwards, this is the rudiment of the external alveolus ; and the arrangement of the appearances from without inwards at this period is the following:—Most externally and forming the boundary of the mouth, is the lip; next we find a deep groove, which separates the lip from the future jaw; then comes the external alveolar ridge; fourthly, another groove, in which the germs of the teeth are de- veloped, the primitive dental groove; fifthly, a rudiment of the internal alveolar ridge; and, sixthly, the rudiment of the future palate bounding the whole internally. At the seventh week the germ of the first decidu- ous molar of the upper jaw has made its appearance, in the form of a " simple, free, granular papilla" of the mucous membrane, projecting from the floor of the primitive dental groove ; at the eighth week, the pa- pilla of the canine tooth is developed; at the ninth week, the papillae of the four incisors (the middle preceding the lateral) appear; and at the tenth week the papilla of the second molar is seen behind the ante- rior molar in the primitive dental groove. So that at this early period, viz. the tenth week, the papillae or germs of the whole ten deciduous teeth of the upper jaw are quite distinct. Those of the lower jaw are a little more tardy; the papilla of the first molar is merely a slight bulging at the seventh week, and the tenth papilla is not apparent until the eleventh week. From about the eighth week the primitive dental groove becomes con- tracted before and behind the first deciduous molar, and laminae of the mucous membrane are developed around the other papillae, which increase in growth and enclose the papillae in follicles with open mouths. At the tenth week the follicle of the first molar is completed, then that of the canine ; during the eleventh and twelfth weeks the follicles of the incisors succeed, and at the thirteenth week the follicle of the posterior deciduous molar. During the thirteenth week the papillae undergo an alteration of form, and assume the shape of the teeth they are intended to represent. And at the same time small membranous processes are developed from the mouths of the follicles ; these processes are intended to serve the purpose of opercula to the follicles, and they correspond in shape with the form of the crowns of the appertaining teeth. To the follicles of the incisor teeth there are two opercula ; to the canine, three; and to the molars a number relative to the number of their tubercles, either four or five. Dur- * " On the Origin and Development of the Pulps and Sacs of the Human Teeth." by John Goodsir, jun., in the Edinburgh Medical and Surgical Journal, January, 1S39. 96 DEVELOPMENT OF TEETH. ing the fourteenth and fifteenth weeks the opercula have completely closed the follicles, so as to convert them into dental sacs, and at the same time the papillae have become pulps. The deep portion of the primitive dental groove, viz. that which contains the dental sacs ofthe deciduous teeth, being thus closed in, the remaining portion, that which is nearer the surface ofthe gum, is still left open, and to this Mr. Goodsir has given the title of secondary dental groove; as it serves for the development of all the permanent teeth, with the exception of the anterior molars. During the fourteenth and fifteenth weeks small lunated inflections of the mucous membrane are formed, immediately to the inner side of the closing opercula of the deciduous dental follicles, commencing behind the incisors and proceeding onwards through the rest; these are the rudiments of the follicles or cavities of reserve of the four permanent incisors, two permanent canines, and the four bicuspides. As the secondary dental groove gradually closes, these follicular inflections of the mucous membrane are converted into closed cavities of reserve, which recede from the surface of the gum and lie immediately to the inner side and in close contact with the dental sacs of the deciduous teeth, being enclosed in their submucous cellular tissue. At about the fifth month the anterior of these cavities of reserve dilate at their distal extre- mities, and a fold or papilla projects into their fundus, constituting the rudiment of the germ of the permanent tooth ; at the same time two small opercular folds are produced at their proximal or small extremities, and convert them into true dental sacs. During the fifth month the posterior part of the primitive dental groove behind the sac of the last deciduous tooth has remained open, and in it has developed the papilla and follicle of the first permanent molar. Upon the closure of this follicle by its opercula, the secondary dental groove upon the summit of its crown forms a large cavity of reserve, lying in contact with the dental sac upon the one side and with the gum on the superficial side. At this period the deciduous teeth, and the sacs of the ten anterior permanent teeth, increase so much in size, w-ithout a corre- sponding lengthening ofthe jaws, that the first permanent molars are gra- dually pressed backwards and upwards into the maxillary tuberosity in the upper jaw, and into the base of the coronoid process of the lower jaw; a position which they occupy at the eighth and ninth months of foetal life. In the infant of seven or eight months the jaws have grown in length, and the first permanent molar returns to its proper position in the dental range. The cavity of reserve, which has been previously elongated by the upward movement ofthe first permanent molar, now dilates into the cavity which that tooth has just quitted; a papilla is developed from its fundus, the cavity becomes constricted, and the dental sac of the second molar tooth is formed, still leaving a portion of the great cavity of reserve in connexion with the superficial side of the sac. As the jaws continue to grow in length, the second permanent dental sac descends from its elevated posi- tion and advances forwards into the dental range, following the same curve with the first permanent molar. The remainder of the cavity of reserve, already lengthened backwards by the previous position of the second molar, again dilates for the last time, developes a papilla and sac in the same manner with the preceding, and forms the third permanent molar or wisdom tooth, which at the age of nineteen or twenty, upon the GROWTH OF TEETH. 97 increased growth of the jaw, follows the course of the first and second molars into the dental range. From a consideration of the foregoing phenomena, Mr. Goodsir has divided the process of dentition into three natural stages:—1. follicular; 2. saccular; 3. eruptive. The first, or follicular stage, he makes to include all the changes which take place from the first appearance of the dental groove and papillae to the closure of their follicles; occupying a period which extends from the sixth week to the fourth or fifth month of intra-uterine existence. The second, or saccular stage, comprises the period when the follicles are shut sacs, and the included papillae pulps: it commences at the fourth and fifth months of intra-uterine existence, and terminates for the median incisors, at the seventh or eighth month of infantile life, and for the wisdom teeth at about the twenty-first year. The third, or eruptive stage, includes the completion of the teeth, the eruption and shedding of the temporary set, the eruption of the perma- nent, and the necessary changes in the alveolar processes. It extends from the seventh month till the twenty-first year. "The anterior permanent molar," says Mr. Goodsir, "is the most remarkable tooth in man, as it forms a transition between the milk and the permanent set." If considered anatomically, i. e. in its development from the primitive dental groove, by a papilla and follicle, " it is decidedly a milk tooth;" if physiologically, " as the most efficient grinder in the adult mouth, we must consider it a permanent tooth." " It is a curious circumstance, and one which will readily suggest itself to the surgeon, that laying out of view the wisdom teeth, which sometimes decay at an early period from other causes, the anterior molars are the permanent teeth which most frequently give way first, and in the most symmetrical manner and at the same time, and frequently before the milk set." Growth of Teeth. — Immediately that the dental follicles have been closed by their opercula, the pulps become moulded into the form of the future teeth: and the bases of the molars divided into two or three por- tions representing the future fangs. The dental sac is composed of two layers, an internal or vascular layer, which was originally a part of the mucous surface of the mouth, and a cellulo-fibrous layer, analogous to the corium of the mucous membrane. Upon the formation of this sac by the closure of the follicle, the mucous membrane resembles a serous mem- brane in being a shut sac, and may be considered as consisting of a tunica propria, which invests the pulp; and a tunica reflexa, which is adherent by its outer surface with the structures in the jaw, and by the inner surface is free, being separated from the pulp by an intervening cavity. As soon as the moulding of the pulp has commenced, this cavity increases and becomes filled with a gelatinous granular substance, the enamel organ, which is ad- Fig. 46* herent to the whole internal surface of the tunica reflexa, but not to the tunica propria and pulp. At the same period, viz., dur- ing the fourth or fifth month, a thin lamina of ivory is formed by the pulp, and occu- pies its most prominent point; if the tooth * a. Capsule of a temporary incisor with the rudiment of the corresponding perma nent tooth attached. 6. Capsule of a molar in the same state. A part of the gum is seen above it and in contact. 9 G 98 TEETH--ERUTTION. be incisor or canine, the newly-formed layer has the figure of a small hollow cone ; if molar, there will be four or five small cones correspond- ing with the number of tubercles in its crown. These cones are united by the formation of additional layers, the pulp becomes gradually sur- rounded and diminishes in size, evolving fresh layers during its retreat into the jaws until the entire tooth with its fangs is completed, and the small cavitas pulpae of the perfect tooth alone remains, communicating through the opening in the apex of each fang with the dental vessels and nerves. The number of roots appears to depend upon the number of nervous filaments sent to each pulp. When the formation of the ivory has commenced, the enamel organ becomes transformed into a laminated tissue, corresponding with the direction of the fibres of the enamel, and the crystalline substance of the enamel is secreted into its meshes by the vascular lining of the sac. The cementum appears to be formed at a later period of life, either by a deposition of osseous substance by that portion of the dental sac, which continues to enclose the fang, and acts as its periosteum, or by the con- version of that membrane itself into bone ; the former supposition is the more probable. The formation of ivory commences in the first permanent molar pre- viously to birth. Eruption.—When the crown of the tooth has been formed and coated with enamel, and the fang has grown to the bottom of its socket by the progressive lengthening of the pulp, the formation of ivory, and the ad- hesion ofthe ivory to the contiguous portion ofthe sac, the pressure ofthe socket causes the reflected portion of the sac and the edge of the tooth to approach, and the latter to pass through the gum. The sac has thereby resumed* its original follicular condition, and has become continuous with the mucous membrane of the mouth. The opened sac now begins to shorten more rapidly than the fang lengthens, and the tooth is quickly drawn upwards by the contraction, leaving a space between the extremity of the unfinished root and the bottom of the socket, in which the growth and completion ofthe fang is more speedily effected. During the changes which have here been described as taking place among the dental sacs contained within the jaws, the septa between the sacs, which at first were composed of spongy tissue, soon became fibrous, and were afterwards formed of bone, which was developed from the sur- face and proceeded by degrees more deeply into the jaws, to constitute the alveoli. The sacs of the ten anterior permanent teeth, at first enclosed in the submucous cellular tissue of the deciduous dental sacs, and received Fig. 47.-J- during their growth into crypts situated behind the deciduous teeth, advanced by degrees beneath the fangs of those teeth, and became separated from them by distinct osseous alveoli. The necks of the sacs of the permanent teeth, by which they originally communicated with the mucous lining of the second- ary groove, still exist, in the form of minute obliterated cords, separated from the deciduous teeth by their alveolus, but com- municating through a minute osseous canal with the fibrous tissue ofthe palate, immediately behind the corresponding de- * Mr. Nasmyth is of opinion that it is "by a process of absorption, and not of disrup- tion, that the tooth is emancipated." Medico-chirurgical Transactions. 1839. •j- Temporary tooth with the capsule of its perr&anent successor attached to it by the gnbernaculum dentis. OS HYOIDES. 99 ciduous teeth. "These cords and foramina are not obliterated in the child," says Mr. Goodsir, "either because the cords are to become useful as ' gubernacula? and the canals as 'itinera dentiumf or, much more probably, in virtue of a law, which appears to be a general one in the development of animal bodies, viz. that parts, or organs, which have once acted an important part, however atrophied they may afterwards become, yet never altogether disappear, so long as they do not interfere with other parts or functions.," Succession.—The periods of appearance of the teeth are extremely irre- gular ; it is necessary, therefore, to have recourse to an average, which, for the temporary teeth, may be stated as follows, the teeth of the lower jaw preceding those of the upper by a short interval:— 7th month, two middle incisors. 18th month, canine. 9th month, two lateral incisors. 24th month, two last molares. 12th month, first molares. The periods for the permanent teeth are, 6| year, first molares. 10th year, second bicuspides. 7th year, two middle incisors. 11th to 12th year, canine. 8th year, two lateral incisors. 12th to 13th year, second molares. 9th year, first bicuspides. 17th to 21st year, last molares. os HYOIDES. The os hyoides forms the second arch developed from the cranium, and gives support to the tongue, and attachment to numerous muscles in the neck. It is named from its resemblance to the Greek letter u, and consists of a central portion or body, of two larger cornua, which project backwards from the body; and two lesser cornua, which ascend from the angles of union between the body and the greater cornua. The body is somewhat quadrilateral, rough and convex on its antero-superior surface, by g' which it gives attachment to muscles; concave and smooth on the postero-inferior surface, by which it lies in contact with the thyro-hyoidean membrane. The greater cornua are flattened from above downwards, and terminated posteri- orly by a tubercle; and the lesser cornua, conical in form, give attachment to the stylo-hyoid liga- ments. In early age and in the adult, the cornua are connected with the body by cartilaginous surfaces and ligamentous fibres; but in old age they become united by bone. Development.—By five centres, one for the body, and one for each cornu. Ossification commences in the greater cornua during the last month of foetal life, and in the lesser cornua and body soon after birth. Attachment of Muscles.—To eleven pairs ; sterno-hyoid, thyro-hyoid, omo-hyoid, pulley of the digastricus, stylo-hyoid, mylo-hyoid, genio- hyoid,' genio-hyo-glossus, hyo-glossus, lingualis, and middle constrictor of the pharynx. It also gives attachment to the stylo-hyoid, thyro-hyoid, and hyo-epiglottic ligaments, and to the thyro-hyoidean membrane. * The os hyoides seen from before. 1. The antero-superior, or convex side of the body. 2. The great cornu of the left side. 3. The lesser cornu ofthe same side. The cornua were ossified to the body of the bone in the specimen from which this figure was drawn. LOO STERNUM. THORAX AND UPPER EXTREMITY. The bones of the thorax are the sternum and ribs; and, of the upper extremity, the clavicle, scapula, humerus, ulna and radius, bones of the carpus, metacarpus, and phalanges. Sternum.—The sternum (fig. 49) is situated in the middle line of the front of the chest, and is oblique in direction, the superior end lying within a few inches of the vertebral column, and the inferior being projected for- wards so as to be placed at a considerable distance from the spine. The bone is flat or slightly concave in front, and marked by five transverse lines which indicate its original subdivision into six pieces. It is convex behind, broad and thick above, flattened and pointed below, and is divisible in the adult into three pieces, superior, middle, and inferior. The superior piece, or manubrium, is nearly quadrilateral; it is broad and thick above, where it presents a concave border (incisura semilu- naris), and narrow at its junction with the middle piece. At each supe- rior angle is a deep articular depression (incisura clavicularis) for the clavicle, and on either side two notches, for the articulation of the carti- lage of the first rib, and one half of the second. The middle piece, or body, considerably longer than the superior, is broad in the middle, and somewhat narrower at each extremity. It pre- sents at either side six articular notches, for the lower half of the second rib, the four next ribs, and the upper half of the seventh. This piece is sometimes perforated by an opening of various magnitude, resulting from arrest of development. The inferior piece (ensiform or xiphoid cartilage) is the smallest of the three, often merely cartilaginous, and very various in appearance, being sometimes pointed, at other times broad and thin, and at other times again, perforated by a round hole, or bifid. It presents a notch at each side for the articulation of the lower half of the cartilage of the seventh rib. Development.—By a variable number of centres, generally ten, namely, two for the manubrium ; one (sometimes two) for the first piece of the body, two for each of the remaining pieces, and one for the ensiform car- tilage. Ossification commences towards the end of the fifth month in the manubrium, the two pieces for this part being placed one above the other. At about the same time the centres for the first and second pieces of the body are apparent; the centres for the third piece of the body appear a few months later, and those for the fourth piece soon after birth. The osseous centre for the ensiform cartilage is so variable in its advent, that it may be present at any period between the third and eighteenth year. The double centres for the body of the sternum are disposed side by side in pairs, and it is the irregular union of these pairs in the last three pieces of the body that gives rise to the large aperture occasionally seen in the sternum, towards its lower part. Union of the pieces of the sternum commences from below and proceeds upwards; the fourth and the third unite at about puberty, the third and the second between twenty and twenty-five, and the second and the first between twenty-five and thirty. The ensiform appendix becomes joined to the body of the sternum at forty or fifty years; and the manubrium to the body only in very old age. Two small pisiform pieces have been described by Beclard and Breschet, RIBS — TRUE AND FALSE. 101 as being situated upon and somewhat behind each extremity of the inci- sura semilunaris of the upper border of the manubrium. These pre- sternal or supra-sternal pieces, which are by no means constant, appear at about the thirty-fifth year. Beclard considers them to be the analogue of the fourchette of birds, and Breschet as the sternal ends of the cer- vical rib. Articulations.—With sixteen bones; viz. with the clavicle and the seven true ribs, at each side. Attachment of Muscles. — To nine pairs and one single muscle; viz. to the pectoralis major, sterno-mastoid, sterno-hyoid, sterno-thyroid, tri- angularis sterni, aponeurosis of the obliquus externus, internus, and trans- versalis muscles, rectus, and diaphragm. Ribs.—The ribs are twelve in number at each side ; the first seven are connected with the sternum, and hence named sternal or true ribs; the remaining five are the asternal or false ribs; and the last two shorter than the rest, and free at their extremities, are the floating ribs. The ribs increase in length from the first to the eighth, whence they again diminish to the twelfth; in breadth they diminish gra- dually from the first to the last, and with the exception of the last two are broader at the anterior than at the posterior end. The first rib is hori- zontal in its direction ; all the rest are oblique, so that the anterior extremity falls considerably below the posterior. Each rib presents an external and in- ternal surface, a superior and inferior border, and twro extremities; it is curved to correspond with the arch of the thorax, and twisted upon itself, so that, when laid on its side, one end is tilted up, while the other rests upon the surface. The external surface is convex, and marked by the attachment of muscles; the internal is flat, and corresponds with the pleura; the superior border is rounded; and the inferior sharp, and grooved upon its inner side, for the attachment of the intercostal muscles.f Near its vertebral extremity, the rib is suddenly bent upon itself; and opposite the bend, upon the external surface, is a rough oblique ridge, which gives attach- ment to a tendon of the sacro-lumbalis muscle, and is called the angle. The distance between the vertebral extremity and the angle increases gradually, from the second to the eleventh rib. Beyond the angle is a * An anterior view of the thorax. 1. The superior piece of the sternum. 2. The middle piece. 3. The inferior piece, or ensiform cartilage. 4. The first dorsal vertebra. 5. The last dorsal vertebra. 6. The first rib. 7. Its head. 8. Its neck, resting against the transverse process of the first dorsal vertebra. 9. Its tubercle. 10. The seventh or last true rib. 11. The costal cartilages of the true ribs. 12. The last two false ribs or floating ribs. 13. The groove along the lower border of the rib. + This groove is commonly described as supporting the intercostal artery, vein, and nerve, but this is not the case. 9* 102 COSTAL CARTILAGES. rough elevation, the tubercle; and immediately at the base and under side of the tubercle a smooth surface for articulation with the extremity of the transverse process of the corresponding vertebra. The vertebral end of the rib is somewhat expanded, and is termed the head, and that portion between the head and the tubercle is the neck. On the extremity of the head is an oval smooth surface, divided by a transverse ridge into two facets, for articulation with two contiguous vertebrae. The posterior surface ofthe neck is rough, for the attachment ofthe middle costo-trans- verse ligament; and upon its upper border is a crest, which gives attach- ment to the anterior costo-transverse ligament. The sternal extremity is flattened, and presents an oval depression, into which the costal cartilage is received. The ribs that demand especial consideration are the first, tenth, eleventh, and twelfth. The^rs^ is the shortest rib; it is broad and flat, and placed horizon- tally at the upper part of the thorax, the surfaces looking upwards and downwards, in place of forwards and backwards as in the other ribs. At about the anterior third of the upper surface of the bone, and near its in- ternal border, is a tubercle which gives attachment to the scalenus anticus muscle, and immediately before and behind this tubercle, a shallow ob- lique groove, the former for the subclavian vein, and the latter for the subclavian artery. Near the posterior extremity of the bone is a thick and prominent tubercle, with a smooth articular surface for the transverse pro- cess of the first dorsal vertebra. There is no angle. Beyond the tuber- osity is a narrow constricted neck; and at the extremity, a head, present- ing a single articular surface. The second rib approaches in some of its characters to the first. The tenth rib has a single articular surface on its head. The eleventh and twelfth have each a single articular surface on the head, no neck or tubercle, and are pointed at the free extremity. The eleventh has a slight ridge, representing the angle, and a shallow groove on the lower border; the twelfth has neither. Costal Cartilages.'—The costal cartilages serve to prolong the ribs forwards to the anterior part of the chest, and contribute mainly to the elasticity of the thorax. They are broad at their attachment to the ribs, and taper slightly towards the opposite extremity; they diminish gradually in breadth from the first to the last; in length they increase from the first to the seventh, and then decrease to the last. The cartilages of the first two ribs are horizontal in direction, the rest incline more and more up- wards. In advanced age the costal cartilages are more or less converted into bone, this change taking place earlier in the male than in the female. The first seven cartilages articulate with the sternum; the three next with the lowTer border of the cartilage immediately preceding, while the last two lie free between the abdominal muscles. All the cartilages ofthe false ribs terminate by pointed extremities. Development.—The ribs are developed by three centres ; one for the central part, one for the head, and one for the tubercle. The last two have no centre for the tubercle. Ossification commences in the body somewhat before its appearance in the vertebrae ; the epiphysal centres for the head and tubercle appear between sixteen and twenty, and are conso- lidated with the rest of the bone at twenty-five. CLAVICLE—SCAPULA. 103 Articulations.—Each rib articulates with two vertebrae, and one costal cartilage, with the exception of the first, tenth, eleventh, and twelfth, which articulate each with a single vertebra only. Attachment of Muscles.—To the ribs and their cartilages are attached twenty-two pairs, and one single muscle. To the cartilages, the subcla- vius, sterno-thyroid, pectoralis major, internal oblique, rectus, transversa- lis, diaphragm, triangularis sterni, internal and external intercostals. To the ribs, the intercostal muscles, scalenus anticus, scalenus posticus, pec- toralis minor, serratus magnus, obliquus externus, obliquus internus, latis- simus dorsi, quadratus lumborum, serratus posticus superior, serratus pos- ticus inferior, sacro-lumbalis, longissimus dorsi, cervicalis ascendens, leva- tores costarum, transversalis, and diaphragm. Clavicle.—The clavicle is a long bone shaped like the italic letter f and extended across the upper part of the side of the chest from the upper piece of the sternum to the point of the shoulder, where it articulates with the scapula. In position it is very slightly oblique, the sternal end being somewhat lower and more anterior than the scapular, and the curves are so disposed that at the sternal end the convexity, and at the scapular the concavity, is directed forwards. The sternal half of the bone is rounded or irregularly quadrilateral, and terminates in a broad articular surface. The scapular half is flattened from above downwards, and broad at its extremity, the articular surface occupying only part of its extent. The upper surface is smooth and convex, and partly subcutaneous; while the under surface is rough and depressed, for the insertion of the subclavius muscle. At the sternal extremity of the under surface is a very rough prominence, which gives attachment to the rhomboid ligament; and at the other extremity a rough tubercle and ridge, for the coraco-clavicular ligament. The opening for the nutritious vessels is seen upon the under surface of the bone. Development.—By two centres; one for the shaft and one for the sternal extremity; the former appearing before any other bone of the skeleton, the latter between fifteen and eighteen. Articulations.—With the sternum and scapula. Attachment of Muscles.—To six; the sterno-mastoid, trapezius, pecto- ralis major, deltoid, subclavius, and sterno-hyoid. Scapula.—The scapula is a flat triangular bone, situated upon the pos- terior aspect and side of the thorax occupying the space from the second to the seventh rib. It is divisible into an anterior and posterior surface, superior, inferior, and posterior border, anterior, superior, and inferior angle, and processes. The anterior surface or subscapular fossa, is concave and irregular, and marked by several oblique ridges which have a direction upwards and outwards. The whole concavity is occupied by the subscapularis muscle, with the exception of a small triangular portion near the superior angle The posterior surface or dorsum is convex, and unequally divided into two portions by the spine ; that portion above the spine is the supra-spin ous fossa ; and, that below, the infra-spinous fossa. The superior border is the shortest of the three: it is thin and concave, and terminated at one extremity by the superior angle, and at the other by the coracoid process. At its inner termination, and formed partly by the 104 SCAPULA. base of the coracoid process, is the supra-scapular notch, for the trans mission of the supra-scapular nerve. The inferior or axillary border is thick, and marked by several grooves and depressions; it terminates superiorly at the glenoid cavity, and infe- riorly at the inferior angle. Immediately below the glenoid cavity is a rough ridge, which gives origin to the long head of the triceps muscle. Upon the posterior surface of the border is a depression for the teres mi- nor; and upon its anterior surface a deeper groove for the teres major; near the inferior angle is a projecting lip, which increases the surface of origin of the latter muscle. The posterior border, or base, the longest ofthe three, is turned towards the vertebral column. It is intermediate in thickness between the supe- rior and inferior, and convex, being considerably inflected outwards towards the superior angle. The anterior angle is the thickest part of the bone, and forms the head ofthe scapula; it is immediately surrounded by a constricted portion, the neck. The head; presents a shallow pyriform Fig. 50. articular surface, the glenoid cavity, having the pointed extremity upwards; and at its apex is a rough depression, which gives at- tachment to the long tendon of the biceps. The superior angle is thin and pointed. The inferior angle is thick, and smooth upon the external surface for the origin of the teres major and for a large bursa over which the upper border of the latissimus dorsi muscle plays. The spine of the scapula, triangular in form, crosses the upper part of its dorsum; it commences at the posterior border by a smooth triangular surface over which the trapezius glides upon a bursa, and terminates at the point of the shoulder in the acromion process. The upper border of the spine is rough and subcutaneous, and gives attach- ment by two projecting lips to the trapezius and deltoid muscles ; the sur- faces of the spine enter into the formation of the supra and infra-spinous fossae. The nutritious foramina of the scapula are situated in the base of the spine. The acromion is somewhat triangular and flattened from above down- wards ; it overhangs the glenoid cavity, the upper surface being rough and subcutaneous, the lower smooth and corresponding with the shoulder- joint. Near its extremity, upon the anterior border, is an oval articular surface, for the end of the clavicle. The coracoid process is a thick, round, and curved process of bone, arising from the upper part of the neck of the scapula, and over arching * A posterior view of the scapula. 1. The supra-spinous fossa. 2. The infra-spinous fossa. 3. The superior border. 4. The supra-scapular notch. 5. The anterior or axil- lary border. 6. The head of the scapula and glenoid cavity. 7. The inferior angle. 8. The neck ofthe scapula, the ridge opposite the number gives origin to the long head of the triceps. 9. The posterior border or base of the scapula. 10. The spine. 11. The triangular smooth surface, over which the tendon ofthe trapezius glides. 12. The acro- mion process. 13. One of the nutritious foramina. 14. The caracoid process. HUMERUS. 105 the glenoid cavity. It is about two inches in length and very strong; it gives attachment to several ligaments and muscles. Development.—By six centres ; one for the body, one for the coracoid process, two for the acromion, one for the inferior angle, and one for the posterior border. The ossific centre for the body appears in the infra- spinous fossa at about the same time with the ossification of the vertebrae ; for the coracoid process during the first year; the acromion process at puberty; the inferior angle in the fifteenth year; and the posterior border at seventeen or eighteen. Union between the coracoid process and body takes place during the fifteenth year; the bone is not complete till manhood. Articulations.—With the clavicle and humerus. Attachment of Muscles.—To sixteen ; by its anterior surface to the sub- scapularis; posterior surface, supra-spinatus and infra-spinatus; superior border, omo-hyoid ; posterior border, levator anguli scapulae, rhomboideus minor, rhomboideus major, and serratus magnus; anterior border, long head of the triceps, teres minor, and teres major; upper angle of the glenoid cavity, to the long tendon of the biceps; spine and acromion to the trapezius and deltoid; coracoid process, to the pectoralis minor, short head of the biceps, and coraco-brachialis. The ligaments attached to the coracoid process are, the coracoid, coraco-clavicular, and coraco-humeral, and the costo-coracoid membrane. Humerus.—The humerus is a long bone divisible into a shaft and two extremities. The superior extremity presents a rounded head; a constriction imme- diately around the base of the head, the neck; a greater and a lesser tuberosity. The greater tuberosity is situated most externally, and is separated from the lesser by a vertical furrow, the bicipital groove, which lodges the long tendon of the biceps. The edges of this groove below the head of the bone are raised and rough, and are called the anterior and posterior bicipital ridge ; the former serves for the insertion of the pecto- ralis major muscle, and the latter of the latissimus dorsi and teres major. The constriction ofthe bone below the tuberosities is the surgical neck, and is so named, in contradistinction to the true neck, from being the seat of the accident called by surgical writers fracture ofthe neck of the humerus. The shaft of the bone is prismoid at its upper part, and flattened from before backwards below. Upon its outer side, at about its middle, is a rough triangular eminence, which gives insertion to the deltoid ; and im- mediately on each side of this eminence is a smooth depression, corres- ponding with the two heads of the brachialis anticus. Upon the innei side ofthe middle ofthe shaft is a ridge, for the attachment ofthe coraco- brachialis muscle; and behind, an oblique and shallow groove, which lodges the musculo-spiral nerve and superior profunda artery. The foramen for the medullary vessels is situated upon the inner surface of the shaft of the bone a little below the coraco-brachial ridge; it is directed downwards. The lower extremity is flattened from before backwards, and is termi nated inferiorly by a long articular surface, divided into two parts by an elevated ridge. The external portion ofthe articular surface is a rounded protuberance, eminentia capitata, which articulates with the cup-shaped 106 ULNA. in Fig. 51.» depression on the head of the radius; the internal portion is a concave and pulley-like surface, trochlea, which arti- culates with the ulna. Projecting beyond the articular surface on each side are the external andinternal condyles, the latter being considerably the longer ; and running up- wards from the condyles upon the borders of the bone are the condyloid ridges, of which the external is the most prominent. Immediately in front of the trochlea is a small depression for receiving the coronoid process of the ulna during flexion of the fore-arm ; and immediately be- hind it a large and deep fossa, for containing the olecra- non process in extension. Development.—By seven centres ; one for the shaft, one for the head, one for the tuberosities, one for the eminen- tia capitata, one for the trochlea, and one for each con- dyle, the internal preceding the external. Ossification commences in the diaphysis of the humerus soon after the clavicle ; in the head and tuberosities, during the second and third years of infantile life ; in the eminentia capitata and trochlea during the third and sixth years ; and in the condyles during the twelfth and fifteenth. The entire bone is consolidated at twenty. Articulations. — With the glenoid cavity of the sca- pula, and with the ulna and radius. Attachment of Muscles.—To twenty-four; by the greater tuberosity to the supra-spinatus, infra-spinatus, and teres minor; lesser tuberosity, sub- scapularis; anterior bicipital ridge, pectoralis major; posterior bicipital ridge and groove, teres major and latissimus dorsi; shaft, external and internal heads of the triceps, deltoid, coraco-brachialis, and brachialis anticus; external condyloid ridge and condyle (condylus extensorius), extensors and supinators of the fore-arm, viz. supinator longus, extensor carpi radialis longior, extensor carpi radialis brevior, extensor communis digitorum, extensor minimi digiti, extensor carpi ulnaris, anconeus, and supinator brevis ; internal condyle (condylus flexorius), flexors and one pronator, viz. pronator radii teres, flexor carpi radialis, palmaris longus, flexor sublimis digitorum, and flexor carpi ulnaris. Ulna.—The ulna is a long bone, divisible into a shaft and two extre- mities. The upper extremity is large, and forms principally the articula- tion of the elbow; while the lower extremity is small, and excluded from the wrist-joint by an inter-articular fibro-cartilage. The superior extremity presents a semilunar concavity of large size, the greater sigmoid notch, for articulation with the humerus; and upon the outer side a lesser sigmoid notch, which articulates with the head of the radius. Bounding the greater sigmoid notch posteriorly is the olecranon process; and overhanging it in front, a pointed eminence with a rough * The humerus of the right side; its anterior surface. 1. The shaft ofthe bone. 2. The head. 3. The anatomical neck. 4. The greater tuberosity. 5. The lesser tube- rosity. 6. The bicipital groove. 7. The anterior bicipital ridge. 8. The posterior bicipital ridge. 9. The rough surfaceinto which the deltoid is inserted. 10. The nu- tritious foramen. 11. The eminentia capitata. 12. The trochlea. 13. The oxtemal condyle. 14. The injernal condyle. 15. The external condyloid ridge. 16. The inter nal condyloid ridge. 17. The fossa for the coronoid process of the ulna. RADIUS. 107 triangular base, the coronoid process. Behind the lesser sigmoid notch, and extending downwards on the side of the olecranon, is a triangular uneven surface, for the anconeus muscle; and upon the posterior surface of the olecranon a smooth triangular surface, which is subcutaneous. The shaft is prismoid in form, and presents three surfaces, anterior, posterior, and internal; and three borders. The anterior surface is occu- pied by the flexor profundis digitorum for the upper three-fourths of its extent; and below by a depression, for the pronator quadratus muscle. A little above its middle is the nutritious foramen, which is directed up- wards. Upon the posterior surface at the upper part of the bone is the triangular uneven depression for the anconeus muscle, bounded inferiorly by an oblique ridge which runs downwards from the posterior extremity ofthe lesser sigmoid notch. Below the ridge the surface is marked into several grooves, for the attachment of the extensor ossis metacarpi, exten- sor secundi internodii, and extensor indicis muscle. The internal surface is covered in for the greater part of its extent by the flexor profundis digi- torum. The anterior border is rounded, and gives origin by its lower fourth to the pronator quadratus; the posterior is more prominent, and affords attachment to the flexor carpi ulnaris and extensor carpi ulnaris. At its upper extremity it expands into the triangular subcutaneous surface of the olecranon. The external or radial border is sharp and prominent, for the attachment of the interosseous membrane. The lower extremity terminates in a small rounded head, capitulum ulna, from the side of which projects the styloid process. The latter pre- sents a deep notch at its base for the attachment of the apex of the trian- gular interarticular cartilage, and by its point gives attachment to the internal lateral ligament. Upon the posterior surface of the head is a groove, for the tendon of the extensor carpi ulnaris; and upon the side opposite to the styloid process a smooth surface, for articulation with the side of the radius. Development.—By three centres ; one for the shaft, one for the inferior extremity, and one for the olecranon. Ossification commences in the ulna shortly after the humerus and radius: the two ends of the bone are cartilaginous at birth. The centre for the lower end appears at about the fifth, and that for the olecranon about the seventh year., The bone is completed at about the twentieth year. Articulations.—With two bones ; the humerus and radius; it is sepa- rated from the cuneiform bone of the carpus by the triangular interarticular cartilage. Attachment of Muscles.—To twelve; by the olecranon, to the triceps extensor cubiti, one head of the flexor carpi ulnaris, and the anconeus; by the coronoid process, to the brachialis anticus, pronator radii teres, flexor sublimis digitorum, and flexor profundus digitorum; by the shaft, to the flexor profundus digitorum, flexor carpi ulnaris, pronator quadratus, anconeus, extensor carpi ulnaris, extensor ossis metacarpi pollicis, extensor secundi internodii pollicis, and extensor indicis. Radius.—The radius is the rotatory bone ofthe fore-arm; it is divisible into a shaft and two extremities: unlike the ulna, its upper extremity is small and merely accessory to the formation of the elbow-joint; while the lower extremity is large, and forms almost solely the joint of the w-rist. The superior extremity, presents a rounded head, depressed upon its 108 RADIUS. / upper surface into a shallow cup. Around the margin ol Fig. 52* the head is a smooth articular surface, which is broad on the inner side, where it articulates with the lesser sigmoid notch of the ulna, and narrow in the rest of its circumfer- ence, to play in the orbicular ligament. Beneath the head is a round constricted neck; and beneath the neck, on its internal aspect, a prominent process, the tuberosity. The surface of the tuberosity is partly smooth, and partly rough; rough below, where it receives the attachment of the ten- don of the biceps; and smooth above, where a bursa is interposed between the tendon and the bone. The shaft of the bone is prismoid, and presents three surfaces. The anterior surface is somewhat concave su- periorly, where it lodges the flexor longus pollicis; and flat below, where it supports the pronator quadratus. At about the upper third of this surface is the nutritious fora- men, which is directed upwards. The posterior surface is round above, where it supports the supinator brevis muscle, and marked by several shallow oblique grooves below, which afford attachment to the extensor muscles of the thumb. The external surface is rounded and con- vex, and marked by an oblique ridge, which extends from the tuberosity to the styloid process at the lower extremity of the bone. Upon the inner margin of the bone is a sharp and prominent crest, which gives attachment to the interosseous membrane. The lower extremity of the radius is broad and triangular, and provided with two ar- ticular surfaces; one at the side of the bone, which is concave to receive the rounded head of the ulna; the other at the extremity, and marked by a slight ridge into two facets, one external and triangular, corresponding writh the scaphoid; the other square, with the semilunar bone. Upon the outer side of the extremity is a strong conical projection, 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 inner edge of the articular surface affords attachment to the base of the inter-articular cartilage of the ulna. Immediately in front of the styloid process is a groove, which lodges the tendons of the extensor ossis metacarpi pollicis, and extensor primi internodii; and behind the process a broader groove, for the tendons of the extensor carpi radialis longior and brevior, and extensor secundi inter- nodii ; behind this is a prominent ridge, and a deep and narrow groove, for 'the tendon of the extensor indicis; and still farther back, part of a broad groove, completed by the ulna, for the tendons of the extensor communis digitorum. Development.—By three centres ; one for the shaft, and one for each ex- tremity. Ossification commences in the shaft soon after the humerus, and before that in the ulna. The inferior centre appears during the second * The two bones of the fore-arm seen from the front. 1. The shaft of the ulna. 2. The greater sigmoid notch. 3. The lesser sigmoid notch, with which the head of the radius is articulated. 4. The olecranon process. 5. The coronoid process. G. The nu- tritious foramen. 7. The sharp riilges upon the two bones to which the interosseous membrane is attached. 8. The capitulum ulna?. 9. The styloid process. 10. The shaft ofthe radius. 11. Its head surrounded by the smooth border for articulation with the orbicular ligament. 12. The neck ofthe radius. 13. Its tuberosity. 14. The oblique line. 15. The lower extremity of the bone. 16. Its styloid process. CARPUS--SCAPHOID AND SEMILUNAR BONES. 109 year, and the superior about the seventh. The bone is perfected at . twenty. Articulations.—With four bones; humerus, ulna, scaphoid, and semi- lunar. Attachment of Muscles.—To nine; by the tuberosity to the biceps ; by the oblique ridge to the supinator brevis, pronator radii teres, flexor sub- limis digitorum and pronator quadratus; by the anterior surface, to the flexor longus pollicis and pronator quadratus ; by the posterior surface, to the extensor ossis metacarpi pollicis, and extensor primi internodii; and by the styloid process, to the supinator longus. Carpus.—The bones of the carpus are eight in number; they are ar- ranged in two rows. In the first row, commencing from the radial side, are the os scaphoides, semilunare, cuneiforme, pisiforme; and in the se- cond row, in the same order, the os trapezium, trapezoides, os magnum, and unciforme. The Scaphoid bone is named from bearing some resemblance to the shape of a boat, being broad at one end, and narrowed like a prow at the opposite, concave on one side, and convex upon the other. It is, how- ever, more similar in form to a cashew nut, flattened and concave upon one side. If carefully examined, it will be found to present a convex and a concave surface, a convex and a concave border, a broad end, and a nar- row and pointed extremity, the tuberosity. To ascertain to which hand the bone belongs, let the student hold it horizontally, so that the convex surface may look backwards (i. e. towards himself), and the convex border upwards: the broad extremity will indi- cate its appropriate hand; if it be directed to the right, the bone belongs to the right; and if to the left, to the left carpus. Articulations.—With^ye bones ; by its con- vex surface with the radius; by its concave surface, with the os magnum and semilunare; and by the extremity of its upper or dorsal border, with the trapezium and trapezoides. Attachments. — By its tuberosity to the ab- ductor pollicis, and anterior annular ligament. The Semilunar bone may be known by having a crescentic concavity, and a some- what crescentic outline. It presents for exami- nation four articular surfaces and twro extremi- ties ; the articular surfaces are, one concave, one convex, and two lateral, one lateral surface being crescentic, the other nearly circular, and divided generally into two facets. The extre- mities are, one dorsal, which is quadrilateral, flat, and indented, for the * A diagram showing the dorsal surface of the bones ofthe carpus, with their articu- lations.—The right hand. 2. The lower end of the radius. 1. The lower extremity of the ulna. 3. The inter-articular fibro-cartilage attached to the styloid process of the ulna, and to the margin of the articular surface of the radius. S. The scaphoid bone. L. The semilunare articulating with five bones. C. The cuneiforme, articulating with three bones. P. The pisiforme, articulating with the cuneiforme only. T. The first bone of the second row,—the trapezium, articulating with four bones. T. The second bone__the trapezoides, articulating also with four bones. M. The os magnum, articu latin^ with seven. U. The unciforme, articulating with five. 10 110 CUNEIFORME--PISIFORME--TRAPEZIUM. attachment of ligaments; the other palmar, which is convex, rounded, and of larger size. To determine to which hand it belongs, let the bone be held perpendi- cularly, so that the dorsal or flat extremity look upwards, and the convex side backwards (towards the holder). The circular lateral surface will point to the side corresponding with the hand to which the bone belongs, Articulations. — With five bones, but occasionally with only four: by its convex surface, with the radius; by its concave surface, with the os magnum; by its crescentic lateral facet, with the scaphoid; and by the circular surface, with the cuneiform bone ahd with the point of the unci- form. This surface is divided into two parts by a ridge when it articu- lates with the unciform as well as with the cuneiform bone. The Cuneiform bone, although somewhat wedge-shaped in form, may be best distinguished by a circular and isolated facet, which articulates with the pisiform bone. It presents for examination three surfaces, abase, and an apex. One surface is very rough and irregular ; the opposite forms a concave articular surface, while the third is partly rough and partly smooth, and presents that circular facet which is characteristic of the bone. The base is an articular surface, and the apex is round and pointed. To distinguish its appropriate hand, let the base be directed backwards and the pisiform facet upwards; the concave articular surface will point to the hand to which the bone belongs. Articulations.—With three bones, and with the triangular fibro-cartilage. By the base, with the semilunare ; by the concave surface, with the unci- forme ; by the circular facet, with the pisiforme ; and by the superior angle of the rough surface, with the fibro-cartilaoe. The Pisiform bone maybe recognised by its small size, and by possess- ing a singular articular facet. If it be examined carefully it will be ob- served to present four sides and two extremities; one side is articular, the smooth facet approaching nearer to the superior than the inferior ex- tremity. The side opposite to this is rounded, and the remaining sides are, one slightly concave, the other slightly convex. If the bone be held so that the articular facet shall look downwards and the extremity which overhangs the articular facet forwards, the concave side will point to the hand to which it belongs. Articulations.—With the cuneiform bone only. Attachments. — To two muscles, the flexor carpi ulnaris, and abductor minimi digiti; and to the anterior annular ligament. The Trapezium (os multangulum majus) is too irregular in form to be compared to any known object; it may be distinguished by a deep groove, for the tendon of the flexor carpi radialis muscle. It is somewhat compressed, and may be divided into two surfaces which are smooth and articular, and three rough borders. One of the articular surfaces is oval, concave in one direction, and convex in the other (saddle-seat shaped); the other is marked into three facets. One of the borders presents the groove for the tendon of the flexor carpi radialis, which is surmounted by a prominent tubercle for the attachment ofthe annular ligament; the other two borders are rough and form the outer side of the carpus. The grooved border is narrow at one extremity and broad at the other, where it pre- sents the groove and tubercle. If the bone be held so that the grooved border look upwards while the apex of this border be directed forwards, and the base with the tubercle TRAPEZOIDES--OS MAGNUM. Ill Dackwards, the concavo-convex surface will point to the hand to which the bone belongs. Articulations.—With four bones; by the concavo-convex surface, with the metacarpal bone ofthe thumb ; and by the three facets of the other articular surface, with the scaphoid, trapezoid, and second metacarpal bone. Attachments.—To two muscles, abductor pollicis and flexor ossis meta- carpi ; and by the tubercle, to the annular ligament. The Trapezoides (os multangulum minus) is a small, oblong, and quadrilateral bone, bent near its middle upon itself (bean-shaped). It presents four articular surfaces and two extremities. One of the surfaces is concavo-convex, i. e. concave in one direction, and convex in the other; another, contiguous to the preceding, is concave, so as to be almost angu- lar in the middle, and is often marked by a small rough depression, for an interosseous ligament; the two remaining sides are flat, and present nothing remarkable. One of the two extremities is broad and of large size, the dorsal; the other, or palmar, is small and rough. If the bone be held perpendicularly, so that the broad extremity be up- wards, and the concavo-convex surface forwards, the angular concave surface will point to the hand to which the bone belongs. Articulations.—With four bones; by the concavo-convex surface, with the second metacarpal bone; by the angular concave surface, with the os magnum ; and by the other two surfaces, with the trapezium and scaphoid. Attachments.—To the flexor brevis pollicis muscle. The Os Magnum (capitatum) is the largest bone of the carpus, and is divisible into a body and head. The head is round for the greater part of its extent, but is flattened on one side. The body is irregularly quadrilateral, and presents four sides and a smooth extremity. Two of the sides are rough, the one being square and flat, the dorsal; the other rounded and prominent, the palmar; the other two sides are articular, the one being concave, the other convex. The ex- tremity is a triangular articular surface, divided into three facets. If the bone be held perpendicularly, so that the articular extremity look upwards and the broad dorsal surface backwards (towards the holder), the concave articular surhiee will point to the hand to which the bone belongs. . Ir/iculations. — With seven bones; by the rounded head, with the cup formed by the sca- phoid and semilunar bone ; by the side of the convex surface, with the trapezoides ; by the concave surface, with the unciforme ; and by the extremity, with the second, third, and fourth metacarpal bones. * The hand viewed upon its anterior or palmar aspect. 1. The scaphoid bone. 2. The semilunare. 3. The cuneiforme. 4. The pisiforme. 5. The trapezium. 6. The groove in the trapezium that lodges the tendon of the flexor carpi radialis. 7. The trapezoides. 8. The os magnum. 9. The unciforme. 10, 10. The five metacarpal bones. 11, 11. The first row of phalanges. 12, 12. The second row. 13, 13. The third row, or ungual phalanges. 14. The first phalanx of the thumb. and last phalanx of the thumb. 15. The second 112 UNCIFORME--METACARPUS. Attachments.—To the flexor brevis pollicis muscle. The Unciforme is a triangular-shaped bone, remarkable for a long and curved process, wdiich projects from its palmar aspect. It presents five surfaces >—three articular, and two free. One of the articular surfaces is divided by a slight ridge into two facets; the other two converge, and meet at a flattened angle.* One of the free surfaces, the dorsal, is rough and triangular; the other, palmar, also triangular, but somewhat smaller, gives origin to the unciform process. If the bone be held perpendicularly, so that the articular surface with two facets look upwards, and the unciform process backwards (towards the holder), the concavity of the unciform process will point to the hand to which the bone belongs. Articulations.—With five bones ; by the two facets on its base, with the fourth and fifth metacarpal bones ; by the two lateral articulating surfaces, with the os magnum and cuneiforme; and by the flattened angle of its apex, with the semilunare. Attachments.—To two muscles, abductor minimi digiti, and flexor brevis minimi digiti; and by the hook-shaped process to the annular liga- ment. Development.—The bones of the carpus are each developed by a single centre ; they are cartilaginous at birth. Ossification commences towards the end of the first year in the os magnum and unciforme ; at the end of the third year in the cuneiforme ; during the fifth year in the trapezium and semilunare; during the eighth, in the scaphoides; the ninth, in the trapezoides: and the twelfth in the pisiforme. The latter bone is the last in the skeleton to ossify; it is, in reality, a sesamoid bone of the tendon of the flexor carpi ulnaris. The number of articulations which each bone of the carpus presents with surrounding bones, may be expressed in figures, which will materially facilitate their recollection; the number for the first row is 5531, and for the second 4475. Metacarpus.—The bones of the metacarpus are five in number. They are long bones, divisible into a head, shaft, and base. The head is rounded at the extremity, and flattened at each side, for the insertion of strong ligaments; the shaft is prismoid, and marked deeply on each side, for the attachment of the interossei muscles ; and the base is irregularly quadrilateral and rough, for the insertion of tendons and ligaments. The base presents three articular surfaces, one at each side, for the adjoining metacarpal bones; and one at the extremity for the carpus. The metacarpal bone of the thumb is one-third shorter than the rest, flattened and broad on its dorsal aspect, and convex on its palmar side; the articular surface of the head is not so round as that of the other meta- carpal bones; and the base has a single concavo-convex surface, to arti- culate with the similar surface ofthe trapezium. The metacarpal bones of the' different fingers may be distinguished by certain obvious characters. The base of the metacarpal bone of the index finger is the largest ofthe four, and presents four articular surfaces. That of the middle finger may be distinguished by a rounded projecting process * When the unciforme does not articulate with the semilunare, this angle is sharp PHALANGES. 113 upon the radial side of its base, and two small circular facets upon its ulnar lateral surface. The base of the metacarpal bone of the ring-finger is small and square, and has two small circular facets to correspond with those of the middle metacarpal. The metacarpal bone of the little finger has only one lateral articular surface. Development.—By two centres; one for the shaft, and one for the digi- tal extremity, with the exception ofthe metacarpal bone ofthe thumb, the epiphysis of which, like that of the phalanges, occupies the carpal end of the bone. Ossification of the metacarpal bones commences in the em- bryo between the tenth and twelfth week, that is, soon after the bones of the fore-arm. The epiphyses make their appearance at the end of the second, or early in the third year, and the bones are completed at twenty. Articulations.—The first with the trapezium ; second, with the trape- zium, trapezoides, and os magnum, and with the middle metacarpal bone ; third, or middle, with the os magnum, and adjoining metacarpal bones; fourth, with the os magnum and unciforme, and with the adjoin- ing metacarpal bones; and, fifth, with the unciforme, and with the meta- carpal bone of the ring-finger. The figures resulting from the number of articulations which each metacarpal bone possesses, taken from the radial to the ulnar side, are 13121. Attachment of Muscles.—To the metacarpal bone of the thumb, three, the flexor ossis metacarpi, extensor ossis metacarpi, and first dorsal inter- osseous ; of the index finger, five, the extensor carpi radialis longior, flexor carpi radialis, first and second dorsal interosseous, and first palmar interosseous; of the middle finger,four, the extensor carpi radialis bre- vior, adductor pollicis, and second and third dorsal interosseous; of the ring finger, three, the third and fourth dorsal interosseous, and second palmar; and of the little finger, four, extensor carpi ulnaris, adductor minimi digiti, fourth dorsal, and third palmar interosseous. Phalanges.—The phalanges are the bones of the fingers ; they are named from their arrangement in rows, and are fourteen in number, three to each finger, and two to the thumb. In conformation they are long- bones, divisible into a shaft, and two extremities. The shaft is compressed from before backwards, convex on its poste- rior surface, and flat with raised edges in front. The metacarpal ex- tremity, or base, in the first row, is a simple concave articular surface, that in the other two rows a double concavity, separated by a slight ridge. The digital extremities of the first and second row present a Dulley-hke surface, concave in the middle, and convex on each side. The ungual extremity of the last phalanx is broad, rough, and expanded into a semi- Innr\v f*rpst" Development.—-By two centres; one for the shaft, and one for the base. Ossification commences first in the third phalanges, then in the first, and lastly in the second. The period of commencement corresponds with that of the metacarpal bones. The epiphyses of the first row appear dur- ino- the third or fourth year, those of the second row during the fourth or fifth, and of the last during the sixth or seventh. The phalanges are per- fected by the twentieth year. Articulations.—The first row, with the metacarpal bones and second 10* H 114 OS INNOMINATUM—ILIUM. row of phalanges; the second row, with the first and third; and the third, with the second row. Attachment of Muscles.—To the base of the first phalanx ofthe thumb four muscles, abductor pollicis, flexor brevis pollicis, adductor pollicis, and extensor primi internodii; and to the second phalanx, two, the flexor longus pollicis, and extensor secundi internodii. To the first phalanx of the second, third, and fourth fingers, one dorsal and one palmar interos- seous, and to the first phalanx of the little finger, the abductor minimi digiti, flexor brevis minimi digiti, and one palmar interosseous. To the second phalanges, the flexor sublimis and extensor communis digitorum; and to the last phalanges, the flexor profundus and extensor communis digitorum. pelvis and lower extremity. The bones of the pelvis are the two ossa innominata, the sacrum, and the coccyx ; and of the lower extremity, the femur, patella, tibia and fibula, tarsus, metatarsus, and phalanges. Os Innominatum.—The os inno- minatum (os coxae) is an irregular flat bone, consisting in the young subject of three parts, which meet at the acetabulum. Hence it is usually described in the adult as divisible into three portions, ilium, ischium, and pubes. The ilium is the supe- rior, broad, and expanded portion which forms the prominence of the hip, and articulates with the sacrum, The ischium is the inferior and strong part of the bone on which we sit. The os pubis is that portion which forms the front of the pelvis, and gives support to the external organs of generation. The Ilium may be described as divisible into an internal and external surface, a crest, and an anterior and posterior border. The internal surface is bounded above by the crest, below by a promi- nent line, the linea ilio-pectinea, and before and behind by the anterior and posterior borders; it is concave and smooth for the anterior two-thirds of its extent, and lodges the iliacus muscle. The posterior third is rough, for articulation with the sacrum, and is divided by a deep groove into two parts; an anterior or auricular portion, which is shaped like the pinna, *The os innominatum of the right side. 1. The ilium; its external surface. 2. The ischium. 3. The os pubis. 4. The crest of the ilium. 5. The superior curved line. 6. The inferior curved line. 7. The surface for the gluteus maximus. 8. The anterioi superior spinous process. 9. The anterior inferior spinous process. 10. The posterior superior spinous process. 11. The posterior inferior spinous process. 12. The spine of the ischium. 13. The great sacro-ischiatic notch. 14. The lesser sacro-ischiatic notch, 15. The tuberosity of the ischium, showing its three facets. 16. The ramus of ihe ischium. 17. The body of the os pubis. 18. The ramus of the pubis. 19. The acetabulum. 20. The foramen thyroideum. Fig. 55* ISCHIUM. 115 and coated by cartilage in the fresh bone ; and a posterior portion, which is very rough and uneven for the attachment of interosseous ligaments. The external surface is uneven, partly convex, and partly concave ; it is bounded above by the crest; below by a prominent arch, which forms the upper segment of the acetabulum ; and before and behind, by the anterior and posterior borders. Crossing this surface in an arched direc- tion, from the anterior extremity of the crest to a notch upon the lower part of the posterior border, is a groove, which lodges the gluteal vessels and nerve, the superior curved line; and below this, at a short distance, a rough ridge, the inferior curved line. The surface included between the superior curved line and the Crest, gives origin to the gluteus medius muscle ; that between the curved lines, to the gluteus minimus; and the rough interval between the inferior curved line and the arch of the aceta- bulum, to one head ofthe rectus. The posterior sixth of this surface is rough and raised, and gives origin to part of the gluteus maximus. The crest of the ilium is arched and curved in its direction like the italic letter/", being bent inwards at its anterior termination, and outwards towards the posterior. It is broad for the attachment of three planes of muscles, which are connected with its external and internal borders or lips, and with the intermediate space. The anterior border is marked by two projections, the anterior superior spinous process, which is the anterior termination of the crest, and the anterior inferior spinous process; the two processes being separated by a notch for the attachment of the sartorius muscle. This border terminates inferiorly in the lip ofthe acetabulum. The posterior border also presents two projections, the posterior superior and the posterior inferior spinous process, separated by a notch. Inferiorly this border is broad and arched, and forms the upper part of the great sacro-ischiatic notch. The Ischium is divisible into a thick and solid portion, the body, and into a thin and ascending part, the ramus; it may be considered also, for convenience of description, as presenting an external and internal surface, and three borders, posterior, inferior, and superior. The external surface is rough and uneven, for the attachment of muscles; and broad and smooth above, where it enters into the formation of the acetabulum. Below the inferior lip of the acetabulum is a notch, which lodges the obturator externus muscle in its passage outwards to the tro- chanteric fossa of the femur. The internal surface is smooth, and some- what encroached upon at its posterior border by the spine. The posterior border of the ischium presents towards its middle a re- markable projection, the spine. Immediately above the spine is a notch of large size, the great sacro-ischiatic, and belowr the spine the lesser sacro- ischiatic notch; the former being converted into a foramen by the lesser sacro-ischiatic ligament, gives passage to the pyriformis muscle, the gluteal vessels and nerve, pudic vessels and nerve, and ischiatic vessels and nerve; and the lesser, completed by the great sacro-ischiatic ligament, to the obturator internus muscle, and to the internal pudic vessels and nerve. The inferior border is thick and broad, and is called the tuberosity. The surface of the tuberosity is divided into three facets; one anterior, which is rough for the origin ofthe semi-membranosus ; and two posterior, which are smooth, and separated by a slight ridge for the semi-tendinosus and biceps muscle. The inner margin of the tuberosity is bounded by a sharp ridge, which gives attachment to a prolongation of the great sacro-ischiatic 116 OS PUBIS. ligament, and the outer margin by a prominent ridge, from which the quadratus femoris muscle arises. The superior border of the ischium is thin, and forms the lower circumference of the obturator foramen. The ramus of the ischium is continuous with the ramus of the pubis, and is slightly everted. The Os Pubis is divided into a horizontal portion or body (horizontal ramus of Albinus), and a descending portion or ramus; it presents for examination an external and internal surface, a superior and inferior bor- der, and symphysis. The external surface is rough, for the attachment of muscles; and pro- minent at its outer extremity, where it forms part of the acetabulum. The internal surface is smooth, and enters into the formation of the cavity of the pelvis. The superior border is marked by a rough ridge, the crest; the inner termination of the crest is the angle; and the outer end, the spine or tubercle. Running outwards from the spine is a sharp ridge, the pecti- neal line, or linea ilio-pectinea, which marks the brim of the true pelvis. In front ofthe pectineal line is a smooth depression, wdiich supports the femoral artery and vein, and a little more externally an elevated promi- nence, the ilio-pectineal eminence, which divides the surface for the femoral vessels, from another depression which overhangs the acetabulum, and lodges the psoas and iliacus muscles. The ilio-pectineal eminence more- over marks the junction ofthe pubes with the ilium. The inferior bordei is broad and deeply grooved, for the passage of the obturator vessels and nerve ; and sharp upon the side of the ramus, to form part of the bound- ary of the obturator foramen. The symphysis is the inner extremity of the body of the bone ; it is oval and rough, for the attachment of a liga- mentous structure analogous to the intervertebral substance. The ramus of the pubes descends obliquely outwTards, and is continuous with the ramus of the ischium. The inner border of the ramus forms with the corresponding bone the arch of the pubes, and at its inferior part is con- siderably everted, to afford attachment to the eras penis. The acetabulum (cavitas cotyloidea) is a deep cup-shaped cavity, situ- ated at the point of union between the ilium, ischium, and pubes; 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 deep rim or lip, which is broad and strong above, wdiere most resistance is required, and marked in front by a deep notch, which is arched over in the fresh subject by a strong ligament, and transmits the nutrient ves- sels into the joint. At the bottom of the cup and communicating with the notch, is a deep and circular pit (fundus acetabuli) which lodges a mass of fat, and gives attachment to the broad extremity of the ligamentum teres. The obturator or thyroid foramen is a large oval interval between the ischium and pubes, bounded by a narrow rough margin, to which a liga- mentous membrane is attached. The upper part of the foramen is increased in depth by the groove in the under surface of the os pubis which lodges the obturator vessels and nerve. Development.—By eight centres ; three principal, one for the ilium, one for the ischium, and one for the pubes; and five secondary, one, the Y-shaped piece for the interval between the primitive pieces in the aceta- bulum, one for the crest of the ilium, one (not constant) for the anteriol and inferior spinous process of the ilium, one for the tuberosity of the ischium, and one (not constant) for the angle of the os pubis. Ossification PELVIS. 117 commences in the primitive pieces, immediately after that in the vertebrae, firstly in the ilium, then in the ischium, and lastly in the pubes; the first ossific deposits being situated near to the future acetabulum. At birth the acetabulum, the crest of the ilium, and the ramus of the pubes and ischium, are cartilaginous. The secondary centres appear at puberty, and the en- tire bone is not completed until the twenty-fifth year. Articulations.—With three bones ; sacrum, opposite innominatum, and femur. Attachments of Muscles and Ligaments.—To thirty-five muscles; to the ilium, thirteen; by the outer lip of the crest, to the obliquus externus for two-thirds, and to the latissimus dorsi for one-third its length, and to the tensor vaginse femoris by its anterior fourth; by the middle crest, to the internal oblique for three-fourths its length, by the remaining fourth to the erector spinae; by the internal lip, to the transversalis for three-fourths, and to the quadratus lumborum by the posterior part of its middle third. By the external surface, to the gluteus medius, minimus and maximus, and to one head of the rectus ; by the internal surface, to the iliacus ; and by the anterior border to the sartorius, and the other head of the rectus. To the ischium, sixteen; by its external surface, the adductor magnus and obturator externus; by the internal surface, the obturator internus and levator ani; by the spine, the gemellus superior, levator ani, coccygeus, and lesser sacro-ischiatic ligament; by the tuberosity, the biceps, semi- tendinosus, semi-membranosus, gemellus inferior, quadratus femoris, erec- tor penis, transversus perinei, and great sacro-ischiatic ligament; and by the ramus, the gracilis, accelerator urinae, and compressor urethrae. To the os pubis, fifteen; by its upper border, the obliquus externus, obliquus internus, transversalis, rectus, pyramidalis, pectineus, and psoas parvus; by its external surface, the adductor longus, adductor brevis, and gracilis ; by its internal surface, the levator ani, compressor urethrae, and obturator internus; and by the ramus, the adductor magnus, and accelerator urinae. pelvis. The pelvis considered Fig. 56* as a whole is divisible into a false and true pelvis; the former is the expanded portion, bounded on each side by the ossa ilii, and separated from the true pelvis by the linea ilio-pec- tinea. The true pelvis is all that portion which is situated beneath the linea ilio-pectinea. This line forms the margin or brim of the true pelvis, while the included area is called the inlet. The form of the inlet is heart-shaped, ob- tusely pointed in front at * A female pelvis. 1. The last lumbar vertebrae. 2, 2. The intervertebral substance connecting the last lumbar vertebra with the fourth and sacrum. 3. The promontory 118 PELVIS. the symphysis pubis, expanded on each side, and encroached upon he- hind by a projection of the upper part of the sacrum, which is named the promontory. The cavity is somewhat encroached upon at each side by a smooth quadrangular plane of bone, corresponding with the internal sur- face of the acetabulum, and leading to the spine of the ischium. In front are two fossae around the obturator foramina, for lodging the obturator internus muscle, at each side. The inferior termination of the pelvis is very irregular, and is termed the outlet. It is bounded in front by the convergence of the rami of the ischium and pubes, which constitute the arch of the pubes ; on each side by the tuberosity of the ischium, and by two irregular fissures formed by the greater and lesser sacro-ischiatic notches; and behind by the lateral borders of the sacrum, and by the coccyx. The pelvis is placed obliquely wTith regard to the trunk of the body, so that the inner surface of the ossa pubis is directed upwards, and would support the superincumbent weight of the viscera. The base of the sacrum rises nearly four inches above the level of the upper border of the sym- physis pubis and the apex of the coccyx, somewhat more than half an inch above its lower border. If a line were carried through the central axis of the inlet, it would impinge by one extremity against the umbilicus, and by the other against the middle of the coccyx. The axis of the inlet is therefore directed downwards and backwards, while that of the outlet points downwards and forwards, and corresponds with a line drawn from the upper part of the sacrum, through the centre of the outlet. The axis of the cavity represents a curve, which corresponds very nearly with the curve of the sacrum, the extremities being indicated by the central points of the inlet and outlet. A know ledge of the direction of these axes is most important to the surgeon, as indicating the line in which instruments should be used in operations upon the viscera of the pelvis, and the direc- tion of force in the removal of calculi from the bladder; and to the accou- cheur, as explaining the course taken by the foetus during parturition. There are certain striking differences between the male and female pel- vis. In the male the bones are thicker, stronger, and more solid, and the cavity deeper and narrower. In the female the bones are lighter and more delicate, the iliac fossae are large, and the ilia expanded ; the inlet, the outlet, and the cavity, are large, and the acetabula farther removed from each other; the cavity is shallow, the tuberosities widely separated, the obturator foramina triangular, and the span of the pubic arch greater. The precise diameter of the inlet and outlet, and the depth of the cavity, are important considerations to the accoucheur. The diameters ofthe inlet or brim are three: 1. Antero-posterior, sacro- pubic or conjugate ; 2. transverse ; and 3. oblique. The antero-posterior of the sacrum. 4. The anterior surface ofthe sacrum, on which its transverse lines and foramina are seen. 5. The tip ofthe coccyx. 6, 6. The iliac fossae, forming the lateral boundaries of the false pelvis. 7. The anterior superior spinous process of the ilium; left side. 8. The anterior inferior spinous process. 9. The acetabulum, a. The notch of the acetabulum, b. The body of the ischium, c. Its tuberosity, d. The spine of the ischium seen through the obturator foramen, e. The os pubis. /. The symphysis pubis. g. The arch of the pubes. h. The angle of the os pubis, t. The spine of the pubes; the prominent ridge between h and i is the crest of the pubes. k, k. The pectineal line of the pubes. I, 1. The ilio-pectineal line; m, m. the prolongation of this line to the pro- montory ofthe sacrum The line represented by h. i, k, k. I, I. and m, m. is the brim of the true pelvis, n. The ilio-pectineal eminence, o. The smooth surface which supports the femoral vessels, p, p. The great sacro-ischiatic notch. FEMUR. 119 57.* extends from the symphysis pubis to the middle of the promontory of the sacrum, and measures four inches. The transverse extends from the middle of the brim on one side to the same point on the opposite, and measures five inches. The oblique extends from the sacro-iliac symphysis on one side, to the margin of the brim corresponding with the acetabulum on the opposite, and also measures five inches. The diameters of the outlet are two, antero-posterior, and transverse. The antero-posterior diameter extends from the lower part of the symphy- sis pubis to the apex of the coccyx; and the transverse, from the posterior part of one tuberosity to the same point on the opposite side ; they both measure four inches. The cavity of the pelvis measures in depth four inches and a half, posteriorly ; three inches and a half in the middle; and one and a half at the symphysis pubis. Femur.—The femur, the longest bone of the skeleton, is situated ob- liquely in the upper part of the lower limb, articulating by means of its head with the acetabulum, and inclining inwards as it descends, until it almost meets its fellow of the opposite side at the knee. In the female this obliquity is greater than in the male, in consequence of the greater breadth of the pelvis. The femur is divisible into a shaft, a superior, and an inferior extremity. At the superior extremity is a rounded head, directed upwards and inwards, and marked just below its centre by an oval depression for the ligamentum teres. The head is supported by a neck, which varies in length and obliquity according to sex and at various periods of life, being long and oblique in the adult male, shorter and more horizontal in the female and in old age. Externally to the neck is a large process, the trochanter major, which presents upon its anterior surface an oval facet, for the attachment of the tendon of the gluteus minimus muscle; and above, a double facet, for the insertion of the gluteus medius. On its posterior side is a vertical ridge, the linea quadrati, for the attachment of the quadratus femoris muscle. Upon the inner side of the trochanter major is a deep pit, the trochanteric or digital fossa, in which are inserted the tendons of the pyriformis, gemellus superior and inferior, and obturator externus and internus muscles. Passing downwards from the trochanter major in front of the bone is an oblique ridge, which forms the inferior boundary of the neck, the anterior intertrochanteric line; and, behind another oblique ridge, the posterior intertrochanteric line, which terminates in a rounded tubercle upon the posterior and inner side of the bone, the trochanter mi- nor. The shaft of the femur is convex and rounded in * The right femur, seen upon the anterior aspect. 1. The shaft. 2. The head. 3. The neck. 4. The great trochanter. 5. The anterior intertrochanteric line. 6 The lesser trochanter. 7. The external condyle. 8. The internal condyle. 9. The tubero- sity for the attachment of the external lateral ligament. 10. The fossa for the tendon of origin ofthe popliteus muscle. 11. The tuberosity for the attachment ofthe internal lateral ligament. 120 FEMUR. front, and covered with muscles; and somewhat concave and raised, into a rough prominent ridge behind, the linea aspera. The linea aspera near the upper extremity of the bone divides into three branches. The ante- rior branch is continued forwards in front of the lesser trochanter, and is continuous with the anterior intertrochanteric line ; the middle is continued directly upwards into the linea quadrati; and the posterior, broad and strongly marked, ascends to the base of the trochanter major. Towards the lower extremity of the bone, the linea aspera divides into two ridges, which descend to the two condyles, and enclose a triangular space upon which rests the popliteal artery. The internal condyloid ridge is less marked than the external, and presents a broad and shallow groove, for the passage of the femoral artery. The nutritious fora- men is situated in or near the linea aspera, at about 'one- third from its upper extremity, and is directed obliquely from below upwTards. The lower extremity of the femur is broad and por- ous, and divided by a smooth depression in front, and by a large fossa (fossa intercondyloidea) behind into two condyles. The external condyle is the broadest and most promi- nent, and the internal the narrowest and longest; the difference in length depending upon the obliquity ofthe femur, in consequence of the separation of the two bones at their upper extremities by the breadth of the pelvis. The external condyle is marked upon its outer side by a prominent tuberosity, which gives attachment to the external lateral ligament; and immediately be- neath this is the fossa, wrhich lodges the tendon of origin of the popliteus. By the internal surface it gives at- tachment to the anterior crucial ligament of the knee- joint ; and by its upper and posterior part, to the exter- nal head of the gastrocnemius and to the plantaris. The internal condyle projects upon its inner side into a tu- berosity, to which is attached the internal lateral liga- ment ; above this tuberosity, at the extremity of the in- ternal condyloid ridge, is a tubercle, for the insertion of the tendon of the adductor magnus ; and beneath the tubercle, upon the upper surface of the condyle, a depression, from which the internal head of the gastrocnemius arises. The outer side of the internal condyle is rough and concave, for the at- tachment of the posterior crucial ligament. Development.—By five centres; one for the shaft, one for each extre mity, and one for each trochanter. The femur is the first of the long bones to show Signs of ossification. In it, ossific matter is found immediately after the maxillae before the termination of the second month of embryonic life. The secondary deposits take place in the following order, in the * A diagram of the posterior aspect of the right femur, showing the lines of attach ment of the muscles. The muscles attached to the inner lip are,—p, the pectineus; a b, the adductor brevis; and a I, the adductor longus. The middle portion is occupied for its whole extent by a m, the adductor magnus; and is continuous superiorly with af, the linea quadrati, into which the quadratus femoris is inserted. The outer lip is occu- pied by g m, the gluteus maximus; and b, the short head of the biceps. PATELLA—TIBIA. 121 condyloid extremity during the last month of foetal life ;* in the head to- wards the end of the first year; in the greater trochanter between the third and the fourth year ; in the lesser trochanter between the thirteenth and fourteenth. The epiphyses and apophyses are joined to the diaphysis in the reverse order of their appearance, the junction commencing after puberty and not being completed for the condyloid epiphysis until after the twentieth year. Articulations.—With three bones; with the os innominatum, tibia, and patella. Attachment of Muscles.—To twenty-three ; by the greater trochanter, to the gluteus medius and minimus, pyriformis, gemellus superior, obturator internus, gemellus inferior, obturator externus, and quadratus femoris; by the lesser trochanter, to the common tendon of the psoas and iliacus. By the linea aspera, its outer lip, to the vastus externus, gluteus maximus, and short head of the biceps ; by its inner lip, to the vastus internus, pec- tineus, adductor brevis, and adductor longus; by its middle to the ad- ductor magnus; by the anterior part of the bone, to the crurseus and subcruraeus; by its condyles, to the gastrocnemius, plantaris, and popliteus. Patella.—The patella is a sesamoid bone, developed in the tendon of the quadriceps extensor muscle, and usually described as a bone of the lower extremity. It is heart-shaped in figure, the broad side being di- rected upwards and the apex downwards, the external surface convex, and the internal divided by a ridge into two smooth surfaces, to articulate with the condyles of the femur. The external articular surface corres- ponding with the external condyle is the larger of the two, and serves to indicate the leg to which the bone belongs. Development. — By a single centre, at about the middle of the third year. Articulations.—With the two condyles of the femur. Attachment of Muscles.—To four; the rectus, crurseus, vastus internus, and vastus externus, and to the ligamentum patellae. Tibia.—The tibia is the inner and larger bone of the leg; it is pris- raoid in form, and divisible into a shaft, an upper and lower extremity. The upper extremity, or head, is large, and expanded on each side into two tuberosities. Upon their upper surface the tuberosities are smooth, to / articulate with the condyles of the femur; the internal articular surface being oval and oblong, to correspond with the internal condyle ; and the external broad and nearly circular. Between the two articular surfaces is a spinous process; and in front and behind the spinous process a rough depression, giving attachment to the anterior and posterior crucial liga- ments. Between the two tuberosities, on the front aspect of the bone, is a prominent elevation, the tubercle, for the insertion of the ligamentum patellfe, and immediately above the tubercle a smooth facet, corresponding with the bursa. Upon the outer side of the external tuberosity is an arti- cular surface, for the head of the fibula ; and upon the posterior part of the internal tuberosity a depression, for the insertion of the tendon of the semimembranosus muscle. * Cruveilhier remarks that this centre is so constant in the last fortnight of foetal life that it may be regarded as an important proof of the fcetus having reached its full term 11 122 FIBULA. Fig. 59.* The shaft of the tibia presents three surfaces ; internal, which is subcutaneous and superficial; external, which is concave and marked by a sharp ridge, for the insertion of the interosseous membrane ; and posterior, grooved, for the attachment of muscles. Near the upper extremity of the posterior surface is an oblique ridge, the popliteal line, for the attachment of the fascia of the popliteus mus cle ; and immediately below the oblique line, the nutritious canal, which is directed downwards. The inferior extremity of the bone is somewhat quadri- lateral, and prolonged on its inner side into a large process, the internal malleolus. Behind the internal malleolus, is a broad and shallow groove, for lodging the tendons ofthe tibialis posticus and flexor longus digitorum; and farther outwards another groove, for the tendon of the flexor longus pollicis. Upon the outer side the surface is con- cave and triangular, rough above, for the attachment of the interosseous ligament; and smooth below, to articulate with the fibula. Upon the extremity of the bone is a trian- gular smooth surface, for articulating with the astragalus. Development.—By three centres ; one for the shaft, and one for each extremity. Ossification commences in the tibia, immediately after the femur; the centre for the head or the bone appears soon after birth, and that for the lower extremity during the second year; the latter is the first to join the diaphysis. The bone is not complete until near the twenty- fifth year. Two occasional centres have sometimes been found in the ti- bia, one in the tubercle, the other in the internal malleolus. Articulations.—With three bones ; femur, fibula, and astragalus. Attachment of Muscles.—To ten; by the internal tuberosity, to the sar- torius, gracilis, semitendinosus, and semimembranosus; by the external tuberosity, to the tibialis anticus and extensor longus digitorum; by the tubercle, to the ligamentum patellae; by the external surface of the shaft, to the tibialis anticus ; and by the posterior surface, to the popliteus, soleus, flexor longus digitorum, and tibialis posticus. Fibula.—The fibula (iregovy), a brooch, from its resemblance, in con- junction with the tibia, to the pin of an ancient brooch) is the outer and smaller bone of the leg; it is long and slender in figure, prismoid in shape, and, like other long bones, is divisible into a shaft and two extremities. The superior extremity or head is thick and large, and depressed upon the upper part by a concave surface, which articulates with the external tuberosity of the tibia. Externally to this surface is a thick and rough prominence, for the attachment of the external lateral ligament of the knee- joint, terminated behind by a styloid process, for the insertion of the ten- don of the biceps. The lower extremity is flattened from without inwards, and prolonged * The tibia and fibula of the right leg, articulated and seen from the front. 1. The shaft of the tibia. 2. The inner tuberosity. 3. The outer tuberosity. 4. The spinous process. 5. The tubercle. 6. The internal or subcutaneous surface of the shaft. 7. The lower extremity of the tibia. 8. The internal malleolus. 9. The shaft of the fibula. 10. Its upper extremity. 11. Its lower extremity, the external malleolus. The sharp border oetween 1 and 6 is the crest of the tibia. FIBULA. 123 60; downwards beyond the articular surface of the tibia, forming the external malleolus. Its external side presents a rough and triangular surface, which is subcutaneous. Upon the internal surface is a smooth triangular facet, to articulate with the astragalus; and a rough depression, for the attach- ment of the interosseous ligament. The anterior border is thin and sharp; and the posterior, broad and grooved, for the tendons of the peronei muscles. To place the bone in its proper position, and ascertain to which leg it belongs, let the inferior or flattened ex- tremity be directed downwards, and the narrow border of the malleolus forwards; the triangular subcutaneous surface will then point to the side corresponding with the limb of which the bone should form a part. The shaft of the fibula is prismoid, and presents three surfaces; external, internal, and posterior; and three borders. The external surface is the broadest of the three ; it commences upon the anterior part of the bone above, and curves around it so as to terminate upon its posterior side below. This surface is completely occu- pied by the two peronei muscles. The internal surface commences on the side of the superior articular surface, and terminates below, by narrowing to a ridge, which is continuous with the anterior border of the malleolus^ It is marked along its middle by the interosseous ridge, which is lost above and below in the inner border ofthe bone. The posterior surface is twisted like the external; it commences above on the posterior side of the bone, and terminates below on its internal side; at about the middle of this surface is the nutritious foramen, which is directed downwards. The internal border commences superiorly in common with the interosseous ridge, and bifurcates inferiorly into two lines, which bound the triangular subcutaneous surface ofthe external malleolus. The external border begins at the base of the styloid process upon the head ofthe fibula, and winds around the bone, following the di- rection of the corresponding surface. The posterior border is sharp and prominent, and is lost inferiorly in the interosseous ridge. Development. —By three centres; one for the shaft, and one for each extremity. Ossification commences in the shaft soon after its appearance in the tibia; at birth the extremities are cartilaginous, an ossific deposit * The tibia and fibula of the right leg articulated and seen from behind. 1. The ar- ticular depression for the external condyle of the femur. 2. The articular depression for the internal condyle; the prominence between the two numbers is the spinous pro- ■vs« 3 The fossa and groove for the insertion of the tendon of the semimembranosus muscle ' 4 The popliteal plane, for the support of the popliteus muscle. 5. Ihe po- nliteal line. 6. The nutritious foramen. 7. The surface of the shaft upon which the flexor longus digitorum muscle rests. 8. The broad groove on the back part of the inner Seolus for the tendons of the flexor longus digitorum and tibialis posticus 9. The groove for the tendon of the flexor longus pollicis. 10 The shaft of the fibula The flexor longus pollicis muscle lies upon this surface of the bone ; its superior limit being marked hv«heP oblique line immediately above the number 11. The styloid processor, he head of the fibula for the attachment of the tendon ofthe biceps muscle. 12. The t ,!ll urface of the lower part of the shaft of the fibula. 13. The external mt.X form^ty the lower extremity of the fibula 14. The groove upon the po, terior part ofthe external malleolus for the tendons ofthe peronei muscles. 124 TARSUS—ASTRAGALUS—CALCANEUS. taking place in the inferior epiphysis during the second year, and in the superior during the fourth or fifth. The inferior epiphysis is the first to become united with the diaphysis, but the bone is not completed until nearly the twenty-fifth year. Articulations.—With the tibia and astragalus. Attachment of Muscles.—To nine ; by the head, to the tendon of the biceps and soleus; by the shaft, its external surface, to the peroneus longus and brevis ; internal surface, to the extensor longus digitorum, extensor proprius pollicis, peroneus tertius, and tibialis posticus; by the posterior surface, to the popliteus and flexor longus pollicis. Tarsus.—The bones of the tarsus are seven in number ; viz. the astra- galus, calcaneus, scaphoid, internal middle, and external cuneiform and cuboid. The Astragalus (os tali) may be recognised by its rounded head, a broad articular facet upon its convex surface, and two articular facets, separated by a deep groove, upon its concave surface. The bone is divisible into a superior and' inferior surface, an external and internal border, and an anterior and posterior extremity. The supe- rior surface is convex, and presents a large quadrilateral and smooth facet somewhat broader in front than behind, to articulate with the tibia. The inferior surface is concave, and divided by a deep and rough groove (sul- cus tali), which lodges a strong interoessous ligament, into twro facets, the posterior large and quadrangular, and the anterior smaller and elliptic, which articulate with the os calcis. The internal border is flat and irre- gular, and marked by a pyriform articular surface, for the inner malleolus. The external presents a large triangular articular facet, for the external malleolus, and is rough and concave in front. The anterior extremity presents a rounded head, surrounded by a constriction somewhat resem- bling a neck; and the posterior extremity is narrow, and marked by a deep groove, for the tendon of the flexor longus pollicis. Hold the astragalus with the broad articular surface upwards, and the rounded head forwards; the triangular lateral articular surface will point to the side to which the bone belongs. Articulations.—With four bones; tibia, fibula, calcaneus, and sca- phoid. The Calcaneus (os calcis) may be known by its large size and oblong figure, by the large and irregular portion which forms the heel, and by two articular surfaces, separated by a broad groove upon its upper side. The calcaneus is divisible into four surfaces, superior, interior, external, and internal; and two extremities, anterior and posterior. The superior surface is convex behind and irregularly concave in front, where it pre- sents two, and sometimes three articular facets, divided by a broad and shallow groove (sulcus calcanei), for the interosseous ligament. The in- ferior surface is convex and rough, and bounded posteriorly by the two inferior tuberosities, of which the internal is broad and large, and the ex- ternal smaller and prominent. The external surface is convex and sub- cutaneous, and marked towards its anterior third by two grooves, often separated by a tubercle, for the tendons ofthe peroneus longus and brevis. The internal surface is concave and grooved, for the tendons and vessels which pass into the sole of the foot. At the anterior extremity of %& SCAPHOID AND CUNEIFORM BONES. 125 surface is a projecting process (sustentaculum tali), Fig. 61* which supports the anterior articulating surface of the 3 astragalus, and serves as a pulley to the tendon of the flexor longus digitorum. Upon the anterior extremity is a flat articular surface, surmounted by a rough pro- jection, which affords one of the guides to the surgeon in the performance of Chopart's operation. The pos- terior extremity is prominent and convex, and consti- tutes the posterior tuberosity; it is smooth for the upper half of its extent, where it corresponds with a bursa; and rough below, for the insertion of the tendo Achillis ; the lower part of this surface is bound- ed by the two inferior tuberosities. Articulations. — With tioo bones; the astragalus and cuboid. In their articulated state a large oblique canal is situated between the astragalus and calcaneus, being formed by the apposition of the twyo grooves sulcus tali and calcanei. This groove is called the sinus tarsi, and serves to lodge a strong interosseous ligament which binds the twro bones together. Attachment of Muscles.—To nine; by the poste- rior tuberosity, to the tendo Achillis and plantaris ; by the inferior tube- rosities and under surface, to the abductor pollicis, abductor minimi digiti, flexor brevis digitorum, flexor accessorius, and to the plantar fascia; and by the external surface, to the extensor brevis digitorum. The Scaphoid bone may be distinguished by its boat-like figure, con- cave on one side, and convex with three facets upon the other. It pre- sents for examination an anterior and posterior surface, a superior and inferior border, and two extremities, one broad, the other pointed and thick. The anterior surface is convex, and divided into three facets, to articulate with the three cuneiform bones; and the posterior concave, to articulate with the rounded head of the astragalus. The superior border is convex and rough, and the inferior somewhat concave and irregular. The external extremity is broad and rough, and the internal pointed and prominent, so as to form a tuberosity. The external extremity sometimes presents a facet of articulation with the cuboid. If the bone be held so that the convex surface with three facets look forwards, and the convex border upwards, the broad extremity will point to the side corresponding with the foot to which the bone belongs. Articulations.—With four bones; astragalus and three cuneiform bones, sometimes also with the cuboid. Attachment of Muscles.—To the tendon of the tibialis posticus. The Internal Cuneiform may be known by its irregular wedge-shape, and by being larger than the two other bones bearing the same name. It * The dorsal surface of the left foot. 1. The astragalus; its superior quadrilateral articular surface. 2. The anterior extremity of the astragalus, which articulates with (4) the scaphoid bone. 3. The os calcis. 4. The scaphoid bone. 5. The internal cuneiform bone. 6. The middle cuneiform bone. 7. The external cuneiform bone. 8. The cuboid bone. 9. The metatarsal bones of the first and second toes. 10. The first phalanx ofthe great toe. 11. The second phalanx of the great toe. 12. The first phalanx ofthe second toe. 13. Its second phalanx. 14. Its third phalanx. 11* 126 CUNEIFORM AND CUBOID BONES. presents for examination a convex and a concave surface, a long and a short articular border, and a small and a large extremity. Place the bone so that the small extremity may look upwards and the long articular border forwards, the concave surface will point to the side corresponding with the foot to which it belongs. The convex surface is internal and free, and assists in forming the inner border of the foot; the concave is external, and in apposition with the middle cuneiform and second metatarsal bone; the long border articulates with the metatarsal bone of the great toe, and the short border with the scaphoid bone. The small extremity (edge) is sharp, and the larger ex- tremity (base) rounded into a broad tuberosity. Articulations. — With four bones; scaphoid, middle cuneiform, and first two metatarsal bones. Attachment of Muscles.—To the tibialis anticus, and posticus. The Middle Cuneiform is the smallest of the three; it is wedge- shaped, the broad extremity being placed upwards, and the sharp end dowmwards in the foot. It presents for examination four articular sur- faces and two extremities. The anterior and posterior surfaces have nothing worthy of remark. One of the lateral surfaces has a long arti- cular facet, extending its whole length, for the internal cuneiform; the other has only a partial articular facet for the external cuneiform bone. If the bone be held so that the square extremity look upwards, the broadest side of the square being towards the holder, the small and partial articular surface will point to the side to which the bone belongs. Articulations. — With four bones; scaphoid, internal and external cuneiform, and second metatarsal bone. Attachment of Muscles.—To the flexor brevis pollicis. The External Cuneiform is intermediate in size between the two preceding, and placed, like the middle, with the broad end upwards and the sharp extremity downwards. It presents for examination five surfaces, and a superior and inferior extremity. The upper extremity is flat, of an oblong square form, and bevelled posteriorly, at the expense of the outer surface, into a sharp edge. If the bone be held so that the square extremity look upwards and the sharp border backwards, the bevelled surface will point to the side corre- sponding with the foot to which the bone belongs. Articulations. — With six bones; scaphoid, middle cuneiform, cuboid, and second, third, and fourth metatarsal bones. Attachment of Muscles.—To ?he flexor brevis pollicis. The Cuboid Bone is irregularly cuboid in form, and marked upon its under surface by a deep groove, 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, which is slightly convex, and assists in forming the dorsum of the foot; the inferior, marked by a prominent ridge, the tuberosity, and a deep groove for the tendon of the peroneus longus; and an external, the smallest of the whu'Je, and deeply notched by the commencement of the peroneal groove. The articular surfaces are, the posterior, which is of large size, and concavo- convex, to articulate with the os calcis; anterior, of smaller size, divided METATARSAL BONES. 127 by a slight ridge into two facets, for the fourth and fifth metatarsal bones; and internal, a small oval articular facet, upon a large and quadrangular surface, for the external cuneiform bom-. If the bone be held so that the plantar surface, with the peroneal groove, look downwards, and the largest articular surface backwards, the small non-articular surface, marked by the deep notch, will point to the side corresponding with the foot to which the bone belongs. Articulations. — With four bones; calcaneus, external cuneiform, and fourth and fifth metatarsal bones, sometimes also with the scaphoid. Attachment of Muscles. — To three ; the flexor brevis pollicis, adductor pollicis, and flexor brevis minimi digiti. Upon a consideration of the articulations of the tarsus it will be ob- served, that each bone articulates with four adjoining bones, with the ex- ception of the calcaneus, which articulates with two, and the external cuneiform with six. Development.—By a single centre for each bone, with the exception of the os calcis, which has an epiphysis for its posterior tuberosity. The centres appear in the following order: calcanean, sixth month; astra- galan, seventh month ; cuboid, tenth month; external cuneiform, during the first year ; internal cuneiform, during the third year; middle cunei- form and scaphoid, during the fourth year. The epiphysis of the calca- neus appears at the ninth year, and is united with the diaphysis at about the fifteenth. The Metatarsal Bones, five in number, are long bones, and divisible therefore into a shaft and two extremities. The shaft is prismoid, and compressed from side to side; the posterior extremity, or base, is square- shaped, to articulate with the tarsal bones, and with each other; and the anterior extremity presents a rounded head, circumscribed by a neck, to articulate with the first row of phalanges. Peculiar Metatarsal Bones.—The first is shorter and larger than the rest, and forms part of the inner border of the foot; its posterior extremity presents only one lateral articular surface, and an oval rough prominence beneath, for the insertion of the tendon of the peroneus longus. The anterior extremity has, upon its plantar surface, two grooved facets, for sesamoid bones. The second is the longest and largest of the remaining metatarsal bones; it presents at its base three articular facets, for the three cuneiform bones; a large oval facet, but often no articular surface, on its inner side, to arti- culate with the metatarsal bone of the great toe, and two externally for the third metatarsal bone. The third may be known by two facets upon the outer side of its base, corresponding with the second, and may be distinguished by its smaller size. The fourth may be distinguished by its smaller size, and by having a single articular surface on each side of the base. The fifth is recognised by its broad base, and by its large tuberosity in place of an articular surface upon its outer side. Development.—Each bone by two centres; one for the body and one for the dio-ital extremity in the four outer metatarsal bones; and one for the body, the other for the base in the metatarsal bone of the great toe. Ossific deposition appears in these bones at the same time with the verte- 28 PHALANGES. Fig. 62.* brae ; the epiphyses, commencing with the great toe and proceeding to the fifth, appear towards the close of the second year, consolidation being effected at eighteen. Articulations.—With the tarsal bones by one ex- tremity, and with the first row of phalanges by the other. The number of tarsal bones with which each metatarsal articulates from within outwards, is the same as between the metacarpus and carpus, one for the first, three for the second, one for the third, two for the fourth, and one for the fifth, forming the cipher 13121. Attachment of Muscles.—To fourteen; to the first the peroneus longus and first dorsal interosseous muscle; to the second, t\vo dorsal interossei and transversus pedis; to the third, two dorsal and one plantar interosseous, adductor pollicis and transversus pedis; to the fourth, two dorsal and one plantar interosseous, adductor pollicis and transversus pedis; to the fifth, one dorsal and one plantar interosseous, peroneus brevis, peroneus tertius, abductor minimi digiti, flexor brevis minimi digiti, and transversus pedis. Phalanges.—There are two phalanges in the great toe, and three in the other toes, as in the hand. They are long bones, divisible into a central portion and extremities. The phalanges of the first row are convex above, concave upon the under surface, and compressed from side to side. The posterior extre- mity has a single concave articular surface, for the head of the metatarsal bone; and the anterior extremity, a pulley-like surface for the second phalanx. The second phalanges are short and diminutive, but somewhat broader than those of the first row. The third, or ungual phalanges, including the second phalanx of the great toe, are flattened from above downwards, spread out laterally at the base, to articulate with the second row, and at the opposite extremity, to support the nail and the rounded extremity of the toe. Development—By two centres ; one for the body and one for the meta- carpal extremity. Ossification commences in these bones after that in the metatarsus, appearing first in the last phalanges, then in the first, and last of all in the middle row. The bones are completed at eighteen. Articulations.—The first row with the metatarsal bones and second phalanges ; the second, of the great toe with the first phalanx, and of the * The sole of the left foot. 1. The inner tuberosity of the os calcis. 2. The outer tuberosity. 3. The groove for the tendon of the flexor longus digitorum ; this figure indicates also the sustentaculum tali. 4. The rounded head of the astragalus 5. The scaphoid bone. 6. Its tuberosity, 7. The internal cuneiform bone ; its broad extremity 8. Ihe middle cuneiform bone. 9. The external cuneiform bone. 10, 11. The cuboid bone. 11. Refers to the groove for the tendon ofthe peroneus longus : the prominence oToeVhlS gr°°Ve and figUre 10 is the tuberosity. 12, 12. The metatarsal bones. ' \\- i,he A™1, Phalanges. 14, 14. The second phalanges of the four lesser toes. 15, 15. Ihe third, or ungual phalanges of the four lesser toes. 16. The last phalanx of the great toe. k SESAMOID BONES. 129 other toes with the first and third phalanges; and the third, with the se- cond row. Attachment of Muscles.—To twenty-three; to ihe first phalanges; great toe, the innermost tendon of the extensor brevis digitorum, abductor pol- licis, adductor pollicis, flexor brevis pollicis, and transversus pedis ; second toe, first dorsal and first palmar interosseous and lumbricalis; third toe, second dorsal and second palmar interosseous and lumbricalis ; fourth toe, third dorsal and third palmar interosseous and lumbricalis; fifth toe, fourth dorsal interosseous, abductor minimi digiti, flexor brevis minimi digiti and lumbricalis. Second phalanges ; great toe, extensor longus pol- licis, and flexor longus pollicis ; other toes, one slip ofthe common tendon of the extensor longus and extensor brevis digitorum, and flexor brevis digitorum. Third phalanges; two slips of the common tendon of the extensor longus and extensor brevis digitorum, and the flexor longus digi- torum. Sesamoid Bones.—These are small osseous masses, developed in those tendons which exert a certain degree of force upon the surface over which they glide, or where, by continued pressure and friction, the tendon would become a source of irritation to neighbouring parts, as to joints. The best example of a sesamoid bone is the patella, developed in the common tendon of the quadriceps extensor, and resting upon the front ofthe knee- joint. Besides the patella, there are four pairs of sesamoid bones included in the number of pieces which compose the skeleton, two upon the meta- carpo-phalangeal articulation of each thumb, and existing in the tendons of insertion of the flexor brevis pollicis, and two upon the corresponding joint in the foot, in the tendons of the muscles inserted into the base of the first phalanx. In addition to these, there is often a sesamoid bone upon the metacarpophalangeal joint of the little finger; and upon the corresponding joint in the foot, in the tendons inserted into the base of the first phalanx; there is one also in the tendon of the peroneus longus muscle, where it glides through the groove in the cuboid bone ; sometimes in the tendons, as they wind around the inner and outer malleolus; in the psoas and iliacus, where they glide over the body of the os pubis ; and in the external head of the gastrocnemius. The bones ofthe tympanum, as they belong to the apparatus of hearing, will be described with the anatomy of the ear. CHAPTER III. ON THE LIGAMENTS. The bones are variously connected with each other in the construction of the skeleton, and the connexion between any two bones constitutes a joint or articulation. If the joint be immovable, the surfaces of the bones are applied in direct contact; but if motion be intended, the opposing surfaces are expanded, and coated by an elastic substance, named carti- lage * a fluid secreted by a membrane closed on all sides lubricates their 130 ARTICULATIONS. surface, and they are firmly held together by means of short bands of glistening fibres, which are called ligaments (ligare, to bind). The study of the ligaments is named syndesmology (tfuv together, dea^og bond), which, with the anatomy of the articulations, forms the subject, of the present chapter. The forms of articulation met with in the human frame may be consi- dered under three classes: Synarthrosis, Amphi-arthrosis, and Diarthrosis. Synarthrosis ( tfuv, agdguoig articulation) is expressive of the fixed form of joint in which the bones are immovably connected with each other. The kinds of synarthrosis are four in number. 1. Sutura. 2. Harmonia. 3. Schindylesis. 4. Gomphosis. The characters of the three first have been sufficiently explained in the preceding chapter, p. 83. It is here only necessary to state that, in the construction of sutures, the substance of the bones is not in immediate contact, but is separated by a layer of membrane which is continuous externally wuth the pericranium and inter- nally with the dura mater. It is the latter connexion which gives rise to the great difficulty sometimes experienced in tearing the calvarium from the dura mater. Cruveilhier describes this interposed membrane as the sutural cartilage; I never saw any structure in the sutures which could be regarded as cartilage, and the history of the formation of the cranial bones would seem to point to a different explanation. The fourth, Gom- phosis (yofjwpoj, a nail), is expressive of the insertion of one bone into another, in the same manner that a nail is fixed into a board; this is il- lustrated in the articulation of the teeth wTith the alveoli of the maxillary bones. Amphi-arthrosis (dfjupi both, agQgutsig) is a joint intermediate in aptitude for motion between the immovable synarthrosis and the movable diarthro- sis. It is constituted by the approximation of surfaces partly coated with cartilage lined by synovial membrane, and partly connected by interosse- ous ligaments, or by the intervention of an elastic fibro-cartilage which adheres to the ends of both bones. Examples of this articulation are seen in the union between the bodies of the vertebrae, of the sacrum with the coccyx, of the pieces of the sternum, the sacro-iliac and pubic symphyses (ffOv, (pueiv, to grow together), and according to some, of the necks of the ribs with the transverse processes. Diarthrosis ( the same disposition on the posterior surface of the articulation. The interarticular, or triangular fibro-cartilage, acts the part of a liga- ment between the kwer extremities of the radius and ulna. It is attached by its apex to a depression on the inner surface of the styloid process of the ulna, and by its base to the edge of the radius. This fibro- cartilage is lined upon its upper surface by a synovial membrane, which forms a duplicature between the radius and ulna, and is called the mem- brana sacciformis. By its lower surface it enters into the articulation of the wrist joint. Actions.—The movements taking place between the radius and the ulna are, the rotation of the former upon the latter; rotation forwards being termed pronation, and rotation backwards supination. In these move- ments the head of the radius turns upon its own axis, within the orbicular ligament and the lesser sigmoid notch of the ulna; while inferiorly the dius. 4. The external lateral ligament inserted inferiorly into (5) the orbicular liga- ment. 6. The posterior extremity of the orbicular ligament, spreading out at its insertion into the ulna. 7. The anterior ligament, scarcely apparent in this-'view of the articula- tion. 8. The posterior ligament, thrown into folds by the extension ofthe joint. * 1. Articular surface of olecranon process of the ulna. 2. Coronoid process. 3. Or- bicular ligament surrounding the neck ofthe radius. Fig. 89* WRIST JOINT. 155 radius presents a concavity which moves upon the rounded head of the ulna. The movements of the radius are chiefly limited by the anterior and posterior inferior ligaments, hence these are not unfrequently ruptured in great muscular efforts. 7. Wrist Joint.—The wrist is a ginglymoid articulation ; the articular surfaces entering into its formation being the radius and under surface of the triangular fibro-cartilage above, and the rounded surfaces of the scaphoid, semilunar, and cuneiform bone below; its ligaments are four in number,— Anterior, Internal lateral, Posterior, External lateral. The anterior ligament is a broad and mem- Fig# 90 * branous layer consisting of three fasciculi, which pass between the lower part of the radius and the scaphoid, semilunar, and cuneiform bone. The posterior ligament, also thin and loose, passes between the posterior surface of the ra- dius, and the posterior surface of the semilunar and cuneiform bone. The internal lateral ligament extends from the styloid process of the ulna to the cuneiform and pisiform bone. The external lateral ligament is attached by one extremity to the styloid process of the ra- dius, and by the other to the side of the scaphoid bone. The radial artery rests on this ligament as it passes backwards to the first metacarpal space. The synovial membrane of the wrist joint lines the under surface of the radius and inter- articular cartilage above, and the first row of bones of the carpus below. The relations of the wrist joint are the flexor and extensor tendons by which it is surrounded, and the radial and ulnar artery. Actions.—The movements of the wrist joint are flexion, extension, ad- duction, abduction, and circumduction. In these motions the articular surfaces glide upon each other. * The ligaments of the anterior aspect of the wrist and hand. 1. The lower part of the interosseous membrane. 2. The anterior inferior radio-ulnar ligament. 3. The an- terior ligament of the wrist joint. 4. Its external lateral ligament. 5. Its internal lateral ligament. 6. The palmar ligaments of the carpus. 7. The pisiform bone with its ligaments. 8. The ligaments connecting the second range of carpal bones with the metacarpal and the metacarpal with each other. 9. The capsular ligament of the carpo- metacarpal articulation of the thumb. 10. Anterior ligament of the metacarpo-pha- langeal articulation ofthe thumb. 11. One ofthe lateral ligaments of that articulation. 12. Anterior ligament ofthe metacarpo-phalangeal articulation ofthe index finger; this ligament has been removed in the other fingers. 13. Lateral ligaments of the same articulation ; the corresponding ligaments are seen in the other articulations. 14. Trans- verse ligament connecting the heads of the metacarpal bones of the index and middle finders : the same ligament is seen between the other fingers. 15. Anterior and one lateral ligament of the phalangeal articulation of the thumb. 16. Anterior and lateral ligaments ofthe phalangeal articulations ofthe index finger; the anterior ligaments are removed in the other fingers. 156 CARPO-METACARPAL ARTICULATIONS. 8. Articulations between the Carpal Bones.—These are amphi-arthrodial joints, with the exception of the conjoined head of the os magnum and unciforme, which is received into a cup formed by the scaphoid, semi- lunar, and cuneiform bone, and constitutes an enarthrosis. The ligaments are, Dorsal, Interosseous fibro-cartilage, Palmar, Anterior annular. The dorsal ligaments are ligamentous bands, that pass transversely and longitudinally from bone to bone, upon the dorsal surface of the carpus. The palmar ligaments are fasciculi of the same kind, but stronger than the dorsal, having the like disposition upon the palmar surface. The interosseous ligaments are fibrocartilaginous lamellae situated be- tween the adjoining bones in each range: in the upper range they close the upper part of the spaces between the scaphoid, semilunar, and cunei- form bones ; in the lower range they are stronger than in the upper, and connect the os magnum on the one side to the unciforme, on the other to the trapezoides, and leave intervals through which the synovial membrane is continued to the bases of the metacarpal bones. The anterior annular ligament is a firm ligamentous band, which con- nects the bones of the two sides of the carpus. It is attached by one ex- tremity to the trapezium and scaphoid, and by the other to the unciform process of the unciforme and the base of the pisiform bone, and forms an arch over the anterior surface ofthe carpus, beneath which the tendons of the long flexors and the median nerve pass into the palm of the hand. The articulation of the pis form bone with the cuneiform, is provided with a distinct synovial membrane, which is protected by fasciculi of liga- mentous fibres, forming a kind of capsule around the joint; they are in- serted into the cuneiforme, unciforme, and base of the metacarpal bone of the little finger. Synovial Membranes.—There are five synovial membranes entering into the composition of the articulations of the carpus:— The first is situated between the lower end of the ulna and the interar- ticular fibro-cartilage ; it is called sacciform, from forming a sacculus be- tween the lateral articulation of the ulna with the radius. The second is situated between the lower surface of the radius and in- terarticular fibro-cartilage above, and the first range of bones ofthe carpus below. The third is the most extensive of the synovial membranes of the wrist; it is situated between the two rows of carpal bones, and passes between the bones of the second range, to invest the carpal extremities of the four metacarpal bones of the fingers. The fourth \s the synovial membrane of the articulation of the meta- carpal bone of the thumb with the trapezium. The fifth is situated between the pisiform and cuneiform bone Actions— Very little movement exists between the bones in each range, but more is permitted between the two ranges. The motions in the latter situation are those of flexion and extension. 9. The Carpo-metacarpal Articulations. — The second row of bones of the carpus articulates with the metacarpal bones of the four fingers by dorsal and palmar ligaments; and the metacarpal bone ofthe thumb with the trapezium by a true capsular ligament. There is also in the ,arpo- r.IETACARPO-PHALANGEAL ARTICULATION. 157 metacarpal articulation a thin interosseous band which passes from the ulnar edge of the os magnum to the line of junction between the third and fourth metacarpal bones. The dorsal ligaments are strong fasciculi which pass from the second range of carpal to the metacarpal bones. The palmar ligaments are thin fasciculi arranged upon the same plan on the palmar surface. The synovial membrane is a continuation of the great synovial membrane of the two rows of carpal bones. The capsular ligament of the thumb is one of the three true capsular ligaments of the skeleton; the other two being the shoulder joint and hip joint. The articulation has a proper synovial membrane. The metacarpal bones of the four fingers are firmly connected at their bases by means of dorsal and palmar ligaments, which ex- tend transversely from one bone to the other, and by interosseous ligaments, which pass between their contiguous surfaces. Their lateral articular facets .are lined by a reflec- tion of the great synovial membrane of the two rows of carpal bones. Actions. — The movements of the metacarpal on the carpal bones are restricted to a slight degree of sliding motion, with the exception of the articulation of the metacarpal bone of the thumb with the trapezium. In the latter articulation, the movements are, flexion, extension, adduction, abduction, and circumduction. 10. Metacarpo-phalangeal Articulation. — The metacarpo-phalangeal articulation is a ginglymoid joint; its ligaments are four in number,— Anterior, Two lateral, Transverse. The anterior ligaments are thick and fibrocartilaginous, and form part ofthe articulating surface of the joints. They are grooved externally for the lodgment of the flexor tendons, and by their internal aspect form part of the articular surface for the head of the metacarpal bone. The lateral ligaments are strong narrow fasciculi, holding the bones together at each side. The transverse ligaments are strong ligamentous bands, passing between the anterior ligaments, and connecting together the heads of the meta- carpal bones of the four fingers. * A diagram showing the disposition of the five synovial membranes of the wrist joint. 1. The sacciform membrane. 2. The second synovial membrane. 3, 3. The third, or large synovial membrane. 4. The synovial membrane between the pisiform bone and the cuneiforme. 5. The synovial membrane of the metacarpal articulation of the thumb. 6. The lower extremity of the radius. 7. The lower extremity of the ulna 8. The interarticular fibro-cartilage. S. The scaphoid bone. L. The semilunare. C. The cuneiforme; the interosseous ligaments are seen passing between these three bones and separating the articulation of the wrist (2) from the articulation of the carpal bones (3). P. The pisiforme. T. The trapezium. 2T. The trapezoides. M. The os magnum. U. The unciforme; interosseous ligaments are seen connecting the os mag- num with the trapezoides and unciforme. 9. The base of the metacarpal bone of the thumb. 10, 10. The bases of the other metacarpal bones. 14 158 HIP JOINT. The expansion of the extensor tendon over the back of the fingers takej the place of a posterior ligament. Actions.—This articulation admits of movement in four different direc- tions, viz. of flexion, extension, adduction, and abduction, the two latter being limited to a small extent. It is also capable of circumduction. 11. Articulation ofthe Phalanges.—These articulations are ginglymoid joints. they are formed by three ligaments. Anterior, Two lateral. The anterior ligament is firm and fibrocartilaginous, and forms part of the articular surface for the head of the phalanges. Externally it is grooved for the reception of the flexor tendons. The lateral ligaments are very strong; they are the principal bond of connexion between the bones. The extensor tendon takes the place and performs the office of a poste- rior ligament. Actions.—The movements of the phalangeal joints are flexion and exten- sion, these movements being more extensive between the first and second phalanges than between the second and third. In connexion with the phalanges, it may be proper to examine certain fibrous bands termed theca or vaginal ligaments, which serve to retain the tendons of the flexor muscles in their position upon the flat surface of their bones. These fibrous bands are attached at each side to the lateral mar- gins of the phalanges; they are thick in the interspaces of the joints, thin where the tendons lie upon the joints, and they are lined upon their inner surface by synovial membrane. LIGAMENTS OF THE LOWER EXTREMITY. The ligaments of the lower extremity, like those of the upper, may be arranged in the order of the joints to which they belong; these are, the 1. Hip joint. 2. Knee joint. 3. Articulation between the tibia and fibula. 4. Ankle joint. 5. Articulation of the tarsal bones. 6. Tarso-metatarsal articulation. 7. Metatarso-phalangeal articulation. 8. Articulation of the phalanges. 1. Hip Joint.—The articulation of the head of the femur with the ace- tabulum constitutes an enarthrosis, or ball-and-socket joint. The articular surfaces are the cup-shaped cavity of the acetabulum and the rounded head of the femur; the ligaments are five in number, viz. Capsular, Cotyloid, Ilio-femoral, Transverse. Teres, The capsular ligament (fig. 83, 8) is a strong ligamentous capsule, em- bracing the acetabulum superiorly, and inferiorly the neck of the femur, and connecting the two bones firmly together. It is much thicker upon the upper part of the joint, where more resistance is required, than upon HIP JOINT--KNEE JOINT. 159 the under part, and extends further upon the neck of the femur on the anterior and superior than on the posterior and inferior side, being attached to the intertrochanteric line in front, to the base of the great tro- chanter above, and to the middle of the neck of the femur behind. The ilio-femoral ligament (fig. 83, 9) is an accessory and radiating band, which descends obliquely from the anterior inferior spinous process of the ilium to the anterior intertrochanteric line, and strengthens the an- terior portion of the capsular ligament. The ligamentum teres (fig. 84, 7), triangular in shape, is attached by a round apex to the depression just below the middle of the head of the femur, and by its base, which divides into two fasciculi, into the borders of the notch of the acetabulum. It is formed by a fasciculus of fibres, of variable size, surrounded by synovial membrane; sometimes the synovial membrane alone exists, or the ligament is wholly absent. The cotyloid ligament (fig. 84, 6) is a prismoid cord of fibro-cartilage, attached around the margin ofthe acetabulum, and serving to deepen that cavity and protect its edges. It is much thicker upon the upper and pos- terior border of the acetabulum than in front, and consists of fibres which arise from the whole circumference of the brim, and interlace with each other at acute angles. The transverse ligament is a strong fasciculus of ligamentous fibres, continuous with the cotyloid ligament, and extended across the notch in the acetabulum. It converts the notch into a foramen, through which the articular branches of the internal circumflex and obturator arteries enter the joint. The fossa at the bottom of the acetabulum is filled by a mass of fat, covered by synovial membrane, which serves as an elastic cushion to the head of the bone during its movements. This was considered by Havers as the synovial gland. The synovial membrane is extensive; it invests the head of the femur, and is continued around the ligamentum teres into the acetabulum, whence it is reflected upon the inner surface of the capsular ligament back to the head of the bone. The muscles immediately surrounding and in contact with the hip joint are, in front, the psoas and iliacus, which are separated from the capsular ligament by a large synovial bursa; above, the short head of the rectus, and the gluteus minimus; behind, the pyriformis, gemellus superior, obtu- rator internus, gemellus inferior, and quadratus femoris; and to the inner side, the obturator externus and pectineus. Actions.—The movements of the hip joint are very extensive ; they are flexion, extension, adduction, abduction, circumduction, and rotation. 2. Knee Joint.—The knee is a ginglymoid articulation of large size, and is provided with numerous ligaments; they are thirteen in number. Anterior or ligamentum patellar, Posterior or ligamentum posticum Winslowii, Internal lateral, Two external lateral, Anterior or external crucial, Posterior or internal crucial, The first five are external to the articulation ; the next five are internal Transverse, Two coronary, Ligamentum mucosum, Ligamenta alaria, Two semilunar fibrocartilages, Synovial membrane. > false. 160 KNEE JOINT. Fig. 92.* to the articulation ; the remaining three are mere folds of synovial mem. brane, and have no title to the name of ligaments. In addition to the ligaments, there are two fibro-cartilages, which are sometimes very erro- neously considered among the ligaments ; and a synovial membrane, which is still more improperly named the capsular ligament. The anterior ligament, or ligamentum patella, is the prolongation of the tendon ofthe extensor muscles ofthe thigh downwards to the tubercle ofthe tibia. It is, therefore, no ligament; and, as we have before stated, that the patella is simply a sesamoid bone, developed in the tendon ofthe extensor muscles for the defence of the front of the knee joint, the ligamentum patellae has no title to con- sideration, either as a ligament of the knee joint or as a ligament of the patella. A small bursa mucosa is situated between the liga- mentum patellae, near its insertion and the front of the tibia, and another of larger size is placed between the anterior surface of the patella and the fascia lata. The posterior ligament, ligamentum posticum Wins- lowii, is a broad expansion of ligamentous fibres which covers the whole of the posterior part of the joint. It is divisible into two lateral portions which invest the condyles of the femur, and a central portion which is depressed, and formed by the interlacement of fasciculi passing in different directions. The strongest of these fasciculi is that which is derived from the tendon of the semi-membranosus, and passes obliquely upwards and outwards, from the posterior part of the inner tuberosity of the tibia to the external condyle. Other accessory fasciculi are given off by the tendon of the popliteus and by the heads of the gastrocnemius. The middle portion of the ligament supports the popliteal artery and vein, and is perforated by several openings for the passage of branches of the azygos articular artery, and for the nerves of the joint. The internal lateral ligament is a broad and trapezoid layer of liga- mentous fibres, attached above to the tubercle on the internal condyle of the femur, and below to the side of the inner tuberosity of the tibia. It is crossed at its lower part by the tendons of the inner hamstring, from which it is separated by a synovial bursa, and it covers in the anterior slip of the semi-membranosus tendon and the inferior internal articular artery. External lateral ligaments.—The long external lateral ligament is a strong rounded cord, which descends from the posterior part of the tubercle upon the external condyle of the femur to the outer part of the head of the fibula. The short external lateral ligament is an irregular fasciculus situated behind the preceding, arising from the external condyle near the origin of the head of the gastrocnemius muscle, and inserted into the posterior part of the head of the fibula. It is firmly connected with the external semilunar fibro-cartilage, and appears principally intended to connect that cartilage with the fibula. The long external lateral ligament * An anterior view of the ligaments of the knee joint. 1. The tendon of the quadri- ceps extensor muscle of the leg. 2. The patella. 3. The anterior ligament, or liga- mentum patella?, near its insertion. 4, 4. The synovial membrane. 5. The internal lateral ligament. 6. The long external lateral ligament. 7. The anterior superioi tibio fibular ligament. KNEE JOINT. 161 Fig. 93* is covered in by the tendon of the biceps, and has passing beneath it the tendon of origin of the popliteus muscle, and the inferior external articular artery. The true ligaments within the joint are the crucial, transverse, and coronary. The anterior, or external crucial ligament, arises from the depression upon the head of the tibia in front ofthe spinous process, and passes upwards and back- wards to be inserted into the inner surface of the outer condyle of the femur, as far as its posterior border. It is smaller than the posterior. The posterior, or internal crucial ligament, arises from the depression upon the head of the tibia, behind the spinous process, and passes upwards and forwards to be inserted into the inner condyle of the femur. This ligament is less oblique and larger than the an- terior. The transverse ligament is a small slip of fibres which extends transversely from the external semilunar fibro-cartilao-e, near its anterior extremity, to the anterior convexity of the internal cartilage. The coronary ligaments are the short fibres by which the convex bor- ders of the semilunar cartilages are connected to the head of the tibia, and to the ligaments surrounding the joint. The semilunar fibro-cartilages are two falciform plates of fibro-cartilage, situated around the margin of the head of the tibia, and serving to deepen the surface of articulation for the condyles of the femur. They are thick along their convex border, and thin and sharp along the concave edge. The internal semilunar fibro-cartilage forms an oval cup for the reception of the internal condyle; it is connected by its convex border to the head of the tibia, and to the internal and posterior ligaments, by means of its coronary ligament; and by its twTo ex- tremities is firmly implanted into the depressions in front and behind the spinous process. The external semilunar fibro-cartilage bounds a circular fossa for the external condyle: it is connected by its convex border with the head of the tibia, and to the external and posterior ligaments, by means of its coronary ligament; by its two extremities it is inserted into the depression between the two projections which constitute the spinous process of the tibia. The two extremities of the external cartilage being inserted into the same fossa form almost a complete circle, * A posterior view of the ligaments of the knee joint. 1. The fasciculus of the liga- mentum posticum Winslowii, which is derived from, 2. the tendon of the semi-mem- branosus muscle; the latter is cut short. 3. The process of the tendon which spreads out in the fascia of the popliteus muscle. 4. The process which is sent inwards be- neath the internal lateral ligament. 5. The posterior part of the internal lateral liga- ment. 6. The long external lateral ligament. 7. The short external lateral ligament. S. The tendon ofthe popliteus muscle cut short. 9. The posterior superior tibio-fibular igament. + The right knee joint laid open from the front, in order to show the internal liga 14* L Fig. 94.f 162 KNEE JOINT. Fig. 95.* and the cartilage being somewhat broader than the internal, nearly covers the articular surface of the tibia. The external semilunar fibro-cartilage besides giving off a fasciculus from its anterior border to constitute the transverse ligament, is continuous by some of its fibres with the extremity of the anterior crucial ligament; posteriorly it divides into three slips; one, a strong cord, ascends obliquely forwards and is inserted into the anterior part of the inner condyle in front of the posterior crucial ligament; another is the fasciculus of insertion into the fossa ofthe spinous process; and the third, of small size, is continuous with the posterior part of the anterior crucial ligament. The ligamentum mucosum is a slender conical process of synovial membrane enclosing a few ligamentous fibres which proceed from the transverse ligament. It is connected, by its apex, with the anterior part of the condyloid notch, and by its base is lost in the mass of fat which projects into the joint beneath the patella. The alar ligaments are two fringed folds of sy- novial membrane, extending from the ligamentum mucosum, along the edges of the mass of fat to the sides of the patella. The synovial membrane of the knee joint is by far the most extensive in the skeleton. It invests the cartilaginous surfaces of the condyles of the femur, of the head of the tibia, and of the inner surface of the patella; it covers both surfaces of the semilunar fibro-cartilages, and is reflected upon the crucial ligaments, and upon the inner surface of the lip-aments which form the circumfe- rence of the joint. On each side of the patella, it lines the tendinous aponeuroses of the vastus inter- nus and vastus externus muscles, and forms a pouch of considerable size between the extensor tendon and the front of the femur. It also forms ments. 1. The cartilaginous surface of the lower extremity of the femur with its two condyles; the figure 5 rests upon the external; the figure 3 upon the internal condyle. 2. The anterior crucial ligament. 3. The posterior crucial ligament. 4. The transverse ligament. 5. The attachment of the ligamentum mucosum; the rest has been removed. 6. The internal semilunar fibro-cartilage. 7. The external fibro-cartilage. 8. A part of the ligamentum patellae turned down. 9. The bursa, situated between the ligamentum patellas and the head of the tibia; it has been laid open. 10. The anterior superior tibio-fibular ligament. 11. The upper part ofthe interosseous membrane ; die opening above this membrane is for the passage ofthe anterior tibial artery. •j- A longitudinal section of the left knee joint, showing the reflection of its synovial membrane. 1. The cancellous structure ofthe lower part of the femur. 2. The tendon of the extensor muscles of the leg. 3. The patella. 4. The ligamentum patellae. 5. The cancellous structure of the head of the tibia. 6. A bursa situated between the ligamentum patellae and the head of the tibia. 7. The mass of fat projecting into the cavity of the joint below the patella. ** The synovial membrane. 8. The pouch of synovial membrane which ascends between the tendon of the extensor muscles of the leg, and the front of the lower extremity of the femur. 9. One of the alar liga- ments ; the other has been removed with the opposite section. 10. The ligamentum mucosum left entire; the section being made to its inner side. 11. The anterior or external crucial ligament. 12. The posterior ligament. The scheme of the synovial membrane, which is here presented to the student, is divested of all unnecessary com- plications. It may be traced from the sacculus (at 8), along the inner surface of the patella; then over the adipose mass (7), from which it throws off the mucous liga ment (10) ; then over the head of the tibia, forming a sheath to the crucial ligaments; then upwards along the posterior ligament and condyles of the femur to the sacculos, whence its examination commenced. TIBIO-FIBULAR ARTICULATIONS. 163 .he folds in the interior ofthe joint, called " ligamentum mucosum," and "ligamenta alaria." The superior pouch of the synovial membrane is supported and raised during the movements of the limb by a small muscle, the subcrureus, which is inserted into it. Betwreen the ligamentum patellae and the synovial membrane is a con- siderable mass of fat, which presses the membrane towards the interior of the joint, and occupies the fossa between the two condyles. Besides the proper ligaments of the articulation, the joint is protected on its anterior part by the fascia lata, which is thicker upon the outer than upon the inner side, by a tendinous expansion from the vastus internus, and by some scattered ligamentous fibres which are inserted into the sides of the patella. Actions.—The knee joint is one of the strongest of the articulations of the body, while at the same time it admits of the most perfect degree of movement in the directions of flexion and extension. During flexion, the articular surface of the tibia glides forward on the condyles of the femur, the lateral ligaments, the posterior, and the crucial ligaments are relaxed, while the ligamentum patella? being put upon the stretch, serves to press the adipose mass into the vacuity formed in the front of the joint. In extension, all the ligaments are put upon the stretch, with the exception of the ligamentum patellae. When the knee is semi-flexed, a partial de- gree of rotation is permitted. 3. Articulation between the Tibia and Fibula.—The tibia and fibula are held firmly connected by means of seven ligaments, viz. Interosseous membrane, Interosseous inferior, Transverse. The anterior superior ligament is a strong fasciculus of parallel fibres, passing obliquely downwards and outwards from the inner tuberosity of the tibia, to the anterior surface of the head of the fibula. The posterior superior ligament is disposed in a similar manner upon the posterior surface of the joint. Within the articulation there is a distinct synovial membrane which is sometimes continuous with that of the knee joint. The interosseous membrane or superior interosseous ligament is a broad layer of aponeurotic fibres which pass obliquely downwards and outwards, from the sharp ridge on the tibia to the inner edge of the fibula, and are crossed at an acute angle by a few fibres passing in the opposite direction. The ligament is deficient above, leaving a considerable interval between the bones, through which the anterior tibial artery takes its course for- wards to the anterior aspect of the leg, and near its lower third there is an opening for the anterior peroneal artery and vein. The interosseous membrane is in relation, in front, with the tibialis anticus, extensor longus digitorum, and extensor propriu.s pollicis muscle, with the anterior tibial vessels and nerve, and with the anterior peroneal artery; and behind, with the tibialis posticus, and flexor longus digitorum muscle, and with the posterior peroneal artery. The inferior interosseous ligament consists of short and strong fibres, which hold the bones firmly together inferiorly, where they are nearly in Anterior, ) , Posterior, \ Anterior, ) , , „ . ' > below. Posterior, S 164 ANKLE JOINT. contact. This articulation is so firm that the fibula is likely to be broken in the attempt to rupture the ligament. The anterior inferior ligament is a broad band, consisting of two fasci culi of parallel fibres which pass obliquely across the anterior aspect of the articulation of the two bones at their inferior extremity, from the tibia to the fibula. The posterior inferior ligament (fig. 98, 2) is a similar band upon the posterior surface of the articulation. Both ligaments project somewhat belowT the margin of the bones, and serve to deepen the cavity of articu- lation for the astragalus. The transverse ligament (fig. 98, 3) is a narrow band of ligamentous fibres, continuous with the preceding, and passing transversely across the back of the ankle joint between the two malleoli. The synovial membrane of the inferior tibio-fibular articulation, is a duplicature ofthe synovial membrane ofthe ankle joint reflected upwards for a short distance between the two bones. Actions.—An obscure degree of movement exists between the tibia and fibula, which is principally calculated to enable the latter to resist injury, by yielding for a trifling extent to the pressure exerted. 4. Ankle joint.—The ankle is a ginglymoid articulation ; the surfaces entering into its formation are the under surface of the tibia with its mal- leolus and the malleolus of the fibula, above, and the surface of the astra- galus with its two lateral facets, below. The ligaments are three in number: Anterior, Internal lateral, External lateral. The anterior ligament is a thin membranous layer, passing from the margin of the tibia to the astragalus in front of the articular surface. It is in relation, in front, with the extensor tendons of the great and lesser toes, with the tendons of the tibialis anticus and peroneus tertius, and with the anterior tibial vessels and nerve. Posteriorly it lies in contact with the extra-synovial adipose tissue and with the synovial membrane. * An internal view of the ankle joint. 1. The internal malleolus of the tibia. 2, 2 Part of the astragalus : the rest is concealed by the ligaments. 3. The os calcis. 4. The scaphoid bone. 5. The internal cuneiform bone. 6. The internal lateral or deltoid ligament. 7. The anterior ligament. 8. The tendo Achillis ; a small bursa is seen interposed between the tendon and the tuberosity of the os calcis. f An external view of the ankle-joint. 1. The tibia. 2. The external malleolus of the fibula. 3, 3. The astragalus. 4. The os calcis. 5. The cuboid bone. 6. The ante- rior fasciculus ofthe external lateral ligament attached to the astragalus. 7. Its middle fasciculus, attached to the os calcis. 8. Its posterior fasciculus, attached to the astra- galus. 9. The anterior ligament of the ankle. TARSAL ARTICULATIONS. 165 The internal lateral or deltoid ligament is a triangular layer of fibres, attached superiorly by its apex to the internal malleolus, and inferiorly by an expanded base to the astragalus, os calcis, and scaphoid bone. Be- neath the superficial layer of this ligament is a much stronger and thicker fasciculus, which connects the apex of the internal malleolus with the side of the astragalus. This internal lateral ligament is covered in and partly concealed by the tendon of the tibialis posticus, and at its posterior part is in relation with the tendon of the flexor longus digitorum, and with that of the flexor longus pollicis. The external lateral ligament consists of three strong fasciculi, which proceed from the inner side ofthe external malleolus, and diverge in three different directions. The anterior fasciculus passes forwards, and is attached to the astragalus; the posterior, backwards, and is connected with the astragalus posteriorly; and the middle, longer than the other two, descends to be inserted into the outer side of the os calcis. "It is the strong union of this bone," says Sir Astley Cooper, "with the tarsal bones, by means of the external lateral ligaments, which leads to its being more frequently fractured than dislocated." The transverse ligament of the tibia and fibula occupies the place of a posterior ligament. It is in relation, behind, with the posterior tibial ves- sels and nerve, and with the tendon of the tibialis posticus muscle; and in front, with the extra-synovial adipose tissue, and synovial membrane. The Synovial membrane invests the cartilaginous surfaces of the tibia and fibula (sending a duplicate upwards between their lower ends), and the upper surface and two sides of the astragalus. It is then reflected upon the anterior and lateral ligaments, and upon the transverse ligament posteriorly. Actions. — The movements of the ankle joint are flexion and extension only, without lateral motion. 5. Articulations ofthe Tarsal Bones. — The ligaments which connect the seven bones of the tarsus to each other are of three kinds,— Dorsal, Plantar, Interosseous. The dorsal ligaments are small fasciculi of parallel fibres, which pass from each bone to all the neighbouring bones with which it articulates. The only dorsal ligaments deserving of particular mention are, the external and posterior calcaneo-aslragaloid, which, with the interosseous ligament, complete the articulation of the astragalus with the os calcis; the superior and internal calcaneo-cuboid ligament. The internal calcaneo-cuboid and the superior calcaneo-scaphoid ligament, which are closely united pos- teriorly in the deep groove which intervenes betwTeen the astragalus and os calcis, separate anteriorly to reach their respective bones; they form the principal bond of connexion between the first and second range of the bones of the foot. It is the division of this portion of these ligaments that demands the especial attention of the surgeon in performing Chopart's operation. The plantar ligaments have the same disposition on the plantar surface ofthe foot; three of them, however, are of a large size, and have especial names, viz. the Calcaneo-scaphoid Long calcaneo-cuboid, Short calcaneo-cuboid. 166 TARSAL ARTICULATIONS. The inferior calcaneo-scaphoid ligament is a broad and fibrocartilaginous band of ligament, which passes forwards from the anterior and inner bor- der of the os calcis and scaphoid bone. In addition to connecting the os calcis and scaphoid, it supports the astragalus, and forms part of the cavity in which the rounded head of the latter bone is received. It is lined upon its upper surface by the synovial membrane of the astragalo-scaphoid articulation. The firm connexion of the os calcis with the scaphoid bone, and the feebleness of the astragalo-scaphoid articu- lation, are conditions favourable to the occasional disloca- tion of the head of the astragalus. The long calcaneo-cuboid ligamentum, or longum plant®, is a long band of ligamentous fibres, which proceeds from the under surface of the os calcis to the rough surface on the under part of the cuboid bone, its fibres being con- tinued onwards to the bases of the third and fourth metatarsal bones. This ligament forms the inferior boundary of a canal in the cuboid bone, through which the tendon of the peroneus longus passes to its in- sertion in the base of the metatarsal bone of the great toe. The short calcaneo-cuboid, or ligamentum breve planta, is situated nearer to the bones than the long plantar ligament, from which it is sepa- rated by adipose tissue ; it is broad and extensive, and ties the under surfaces of the os calcis and cuboid bone firmly together. The interosseous ligaments are five in number; they are short and strong ligamentous fibres situated between adjoining bones, and firmly attached to their rough surfaces. One of these, the calcaneo-astragaloid, is lodged in the groove between the upper surface of the os calcis and the lower of the astragalus. It is large and very strong, consists of vertical and oblique fibres, and serves to unite the os calcis and astragalus solidly together. The second interosseous ligament, also very strong, is situated between the sides of the scaphoid and cuboid bone ; while the three re- maining interosseous ligaments connect strongly together the three cunei- form bones and the cuboid. The synovial membranes of the tarsus are four in number; one for the posterior calcaneo-astragaloid articulation ; a second, for the anterior cal- caneo-astragaloid and astragalo-scaphoid articulation. Occasionally an additional small synovial membrane is found in the anterior calcaneo- astragaloid joint; a third, for the calcaneo-cuboid articulation ; and a fourth, the large tarsal synovial membrane, for the articulations between the scaphoid and three cuneiform bones, the cuneiform bones with each other, the external cuneiform bone with the cuboid, and the two external cuneiform bones with the bases of the second and third metatarsal bones. The prolongation which reaches the metatarsal bones passes forwards be- tween the internal and middle cuneiform bones. A small synovial mem- brane is sometimes met with between the contiguous surfaces of the scaphoid and cuboid bone. * A posterior view of the ankle joint. 1. The lower part of the interosseous mem- brane. 2. The posterior inferior ligament connecting the tibia and fibula. 3. The transverse ligament. 4. The internal lateral ligament. 5. The posterior fasciculus of the internal lateral ligament. 6. The middle fasciculus of the external lateral ligament. 7. The synovial membrane of the ankle joint. 8. The os calcis. TARSO-METATARSAL ARTICULATION. 167 Actions. — The movements permitted by the articulation between the astragalus and os calcis, are a slight degree of gliding, in the directions forwards and baclcwards and laterally from side to side. The movements of the second range of tarsal bones is very trifling, being greater between the scaphoid and three cuneiform bones than in the other articulations. The movements occurring between the first and second range are the most considerable; they are adduction and abduction, and, in a minor degree, flexion, which increases the arch of the foot, and extension, which flattens the arch. 6. Tarso-metatarsal Articulation.—The ligaments of this articulation are, Dorsal, Plantar, Interosseous. Fig. 99. The dorsal ligaments connect the metatarsal to the tarsal bones, and the metatarsal bones with each other. The precise arrangement of these ligaments is of little importance, but it may be remarked, that the base of the second metatarsal bone, articulating with the three cuneiform bones, receives a ligamentous slip from each, while the rest, articulating with a single tarsal bone, receive only a single tarsal slip. The plantar ligaments have the same disposition on the plantar surface. The interosseous ligaments are situated between the bases of the metatarsal bones of the four lesser toes; and also between the bases of the second and third metatarsal bones, and the internal and external cunei- form bones. The metatarsal bone of the second toe is implanted by its base between the internal and external cuneiform bones, and is the most strongly articulated of all the metatarsal bones. This disposition must be recollected in amputation at the tarso-metatarsal articulation. The synovial membranes of this articulation are three il in number: one for the metatarsal bone of the great toe; one for the second and third metatarsal bones, which is continuous with the great tarsal synovial mem- brane ; and one for the fourth and fifth metatarsal bones. Actions. — The movements of the metatarsal bones upon the tarsal, and upon each other, are very slight; they are such only as contribute to the strength of the foot by permitting of a certain degree of yielding to opposing forces. 7. Metatarsal-phalangeal Articulation.—The ligaments of this articula- tion, like those of the articulation between the first phalanges and meta- carpal bones ofthe hand, are, Anterior or plantar, Two lateral, Transverse. * The ligaments of the sole of the foot. 1. The os calcis. 2. The astragalus. 3. The tuberosity of the scaphoid bone. 4. The long calcaneo-cuboid ligament. 5. Part of the short calcaneo-cuboid ligament. 6. The calcaneo-scaphoid ligament. 7. The plantar tarsal li°nments. 8, 8. The tendon of the peroneus longus muscle. 9, 9. Plantar tarso- metatarsal ligaments. 10. Plantar ligament of the metatarso-phalangeal articulation of the great toe- the same ligament is seen upon the other toes. 11. Lateral ligaments of the metatarso-phalangeal articulation. 12. Transverse ligament. 13. The lateral liga- ments of the phalanges of the great toe; the same ligaments are seen upon the other toes. J 68 STRUCTURE OF MUSCLE. The anterior or plantar ligaments are thick and fibrocartilaginous, and form part ofthe articulating surface of the joint. The lateral ligaments are short and very strong, and situated on each side of the joints. The transverse ligaments are strong bands, which pass transversely be- tween the anterior ligaments. The expansion of the extensor tendon supplies the place of a dorsal ligament. Actions. — The movements of the first phalanges upon the rounded heads ofthe metatarsal bones, are flexion, extension, adduction and abduc- tion. 8. Articulation ofthe Phalanges.—The ligaments of the phalanges are the same as those of the fingers, and have the same disposition; their actions are also similar. They are, Anterior or plantar, Two lateral. CHAPTER IV. ON THE MUSCLES. Muscles are the moving organs of the animal frame; they constitute by their size and number the great bulk of the body, upon which they bestow form and symmetry. In the limbs they are situated around the bones, which they invest and defend, while they form to some ofthe joints a principal protection. In the trunk they are spread out to enclose cavi- ties and constitute a defensive wall capable of yielding to internal pressure and again returning to its original position. Their colour presents the deep red which is characteristic of flesh, and their form is variously modified, to execute the varied range of movements which they are required to effect. Muscle is composed of a number of parallel fibres placed side by side, and supported and held together by a delicate web of areolar tissue; so that, if it were possible to remove the muscular substance, we should have remaining a beautiful reticular framework, possessing the exact form and size of the muscle without its colour and solidity. Towards the extremity of the organ the muscular fibre ceases, and the areolar structure becomes aggregated and modified so as to constitute those glistening fibres and cords by which the muscle is tied to the surface of bone, and which are called tendons Almost every muscle in the body is connected with bone, either by tendinous fibres, or by an aggregation of those fibres constituting Ll?t°ni ^ uG T10u 1S S° firm' that' under extreme violence, the bone itself rather breaks than permits ofthe separation of the tendon from its attachment. In the broad muscles the tendon is spread so as to form JJid^read oun ap°neur0SlS ("**> lon8*J "*«,• nervus-a nerve ,n Snn ^T' TT modifi'Cations in *e arrangement of their fibres in relation to their tendinous structure. Sometimes they are completely linn^ to^e™^ "" thC Whhe fibrCS °f the b°^ ~* i *• - nas since been STRUCTURE OF MUSCLE. 169 longitudinal, and terminate at each extremity in tendon, the entire muscle being fusiform in its shape ; in other situations they are disposed like the rays of a fan, converging to a tendinous point, as the temporal, pectoral, glutei, &c, and constitute a radiate muscle. Again, they are penniform, converging like the plumes of a pen to one side of a tendon, which runs the whole length of the muscle as in the peronei; or bipenniform, con- verging to both sides of the tendon. In other muscles the fibres pass obliquely from the surface of a tendinous expansion spread out on one side, to that of another extended on the opposite side, as in the semi- membranosus ; or, they are composed of penniform or bipenniform fasci- culi as in the deltoid, and constitute a compound muscle. The nomenclature of the muscles is defective and confused, and is generally derived from some prominent character which each muscle pre- sents ; thus, some are named from their situation, as the tibialis, peroneus; others from their uses, as the flexors, extensors, adductors, abductors, le- vators, tensors, &c. Some again from their form, as the trapezius, trian- gularis, deltoid, &c.; and others from their direction, as the rectus, obliquus, transversalis, &c. Certain muscles have received names ex- pressive of their attachments, as the sterno-mastoid, sterno-hyoid, &c.; and others, of their divisions, as the biceps, triceps, digastricus, complexus, &c. In the description of a muscle we express its attachment by the words " origin" and " insertion;" the term origin is generally applied to the more fixed or central attachment, or to the point towards which the motion is directed, while insertion is assigned to the more movable point, or to that most distant from the centre ; but there are many exceptions to this principle, and as many muscles pull equally by both extremities, the use of such terms must be regarded as purely arbitrary. In structure, muscle is composed of bundles of fibres of variable size called fasciculi, which are enclosed in a cellular membranous investment or sheath, and the latter is continuous with the cellular framework of the fibres. Each fasciculus is composed of a number of smaller bundles, and these of single fibres, which, from their minute size and independent ap- pearance, have been distinguished by the name of ultimate fibres. The ultimate fibre is found by microscopic investigation to be itself a fasciculus (ultimate fasciculus), made up of a number ot ultimate fibrils enclosed in a delicate sheath or myolemma.* Two kinds of ultimate muscular fibre exist in the animal economy ; viz., that of voluntary or animal life, and that of involuntary or organic life. The ultimate fibre of animal life is known by its size, by its uniformity of calibre, and especially by the very beautiful transverse markings which occur at short and regular distances throughout its whole extent. It also presents other markings or strke, having a longitudinal direction, which indicate the existence of fibrillae within its myolemma. The myolemma, or investing sheath of the ultimate fibre, is thin, structureless and trans- parent. * In the summer of 1836, while engaged with Dr. Jones Quain in the examination of the animal ti^ues with a simple dissecting microscope, constructed by Powell, I first s-iw that the ultimate fibre of muscle was invested by a proper sheath, for which I pro- nosed the term " Myolemma;" a term which was adopted by Dr. Quain in the fourth edition of his " Elements of Anatomy." We at that time believed that the transverse folding of that sheath gave rise to the appearance of transverse stria?, an opinion which subsequent examinations proved to be incorrect. Mr. Bowman employs the term '• Sar- colemnia," as synonymous with Myolemma. 15 170 STRUCTURE OF MUSCLE. According to Mr. Bowman* the ultimate fibres are polygonal in shape [fig. 100] from mutual pressure. They are also variable in their size, not merely in different classes and genera of animals and different sexes, but even in the same muscle. For example, the average diameter of the ulti- mate fibre in the human female is 4 £4, while that ofthe male is 3£5, the average of both being 4 J-3. The largest fibres are met with in fishes, in which animals they average 2|3 ; the next largest are found in man, while in other classes they range in the following order:—insects ?-Jg ; reptiles 4g? 5 mammalia sJ-r; birds g^. The ultimate fibrils of animal life, according to Mr. Bowman, are beaded filaments consisting of a regular succession of segments and constrictions, the latter being narrower than the former, and the component substance probably less dense. Fig. lOO.f Fig. 101.* An ultimate fibre consists of a bundle of these fibrils, which are so dis- posed that all the segments and all the constrictions correspond, and in this manner give rise to the alternate light and dark lines of the transverse striae. The fibrils are connected together with very different degrees of closeness in different animals; in man they are but slightly adherent, and distinct longitudinal lines of junction may be observed between them; they also separate very easily when macerated for some time. Besides the more usual separation of the ultimate fibre into fibrils, it breaks when stretched, into transverse sections [fig. 101,] corresponding with the dark line of the striae, and consequently with the constrictions of the fibrillae. When this division occurs with the greatest facility, the longitudinal lines are indistinct, or scarcely perceptible. "In fact," says Mr. Bowman, " the primitive fasciculus seems to consist of primitive component segments or particles, arranged so as to form, in one sense, fibrilloe, and in another sense, discs ; and which of these two may happen to present itself to the observer, will depend on the amount of adhesion, endways or sideways, existing between the segments. Generally, in a recent fasciculus, there are transverse striae, showing divisions into discs, and longitudinal stria?, marking its composition by fibrillae." Mr. Bowman has observed that in the substance of the ultimate fibre there exist minute " oval or circular discs, frequently concave on one or * On the Minute Structure and Movements of Voluntary Muscle. By Wm. Bowman, Esq. From the Philosophical Transactions for 1840. transverse section of ultimate fibres of the biceps, copied from the illustrations to Mr. Bowman s paper. In this figure the polygonal form of the fibres is seen, and their composition of ultimate fibrils. * An ultimate fibre, in which the transverse splitting into discs, in the direction ofthe Constrictions of the ultimate fibrils is seen. From Mr. Bowman's paper. STRUCTURE OF MUSCLE. 171 102.* Fig. 1034 i@ a0 both surfaces, and containing, somewhere near the centre, one, two, or Jiree minute dots or granules." Occasionally they are seen to present ir- regularities of form, which Mr. Bowman is inclined to regard as accidental. They are situated between, and are connected with the fibrils, and are distributed in pretty equal numbers through the fibre. These corpuscles are the nuclei of the nucleated cells from which the muscular fibre was originally developed. From ob- serving, however, that their " absolute number is far greater in the adult than in the foetus, while their number, relatively to the bulk of the fasciculi, at these two epochs, remains nearly the same," Mr. Bowman regards it as certain, that " during development, and subsequently, a further and successive deposit of cor- puscles" takes place. The corpuscles are brought into view only when the muscular fibre is acted upon by a solution of " one ofthe milder acids, as the citric." According to my own investigations,! the ultimate fibril of animal life is cylindrical when isolated, and probably polygonal from pressure when forming part of an ultimate fibre or fasciculus. It measures in diameter ^3(jM, mola, i. e. attached to the molar ridge of the lower jaw) is a broad triangular plane of muscular fibres, forming, with its fellow of the opposite side, the inferior wall or floor of the mouth. It arises from the molar ridge on the lower jaw, and proceeds obliquely inwards to be inserted into the raphe of the two muscles and into the body of the os hyoides; the raphe is sometimes deficient at its anterior part. Relations. — By its superficial, or inferior surface, with the platysma myoides, the digastricus, the supra-hyoidean fascia, the submaxillary gland and the submental artery. By its deep or superior surface, with the genio- hyoideus, the genio-hyo-glossus, the stylo-glossus, the gustatory nerve, the hypoglossal nerve, Wharton's duct, the sublingual gland, and the mucous membrane of the floor of the mouth. After the mylo-hyoideus has been examined, it should be cut away from its origin and insertion, and completely removed. The view of the next muscles would also be greatly improved by dividing the lower jaw on the near side of the symphysis, and drawing it outwards, or by removing it altogether, if the ramus have been already cut across in dissecting the in- ternal pterygoid muscle. The tongue may then be drawn out of the mouth by means of a hook. The Genio-hyoideus (yevsov, the chin) arises from a small tubercle upon the inner side of the symphysis of the lower jaw, and is inserted into the upper part ofthe body of the os hyoides. It is a short and slender muscle, very closely connected with the border of the followino-. Relations.—By its superficial or inferior surface, with the mylo-hyoideus, by the deep or superior surface, with the lower border of the genio-hyo- glossus. The Genio-hyo-glossus (yXufftfa, the tongue) is a triangular muscle, narrow and pointed at its origin from the lower jaw, broad and fan-shaped at its attachment to the tongue. It arises from a tubercle immediately above that of the genio-hyoideus, and spreads out to be inserted into the whole length of the tongue, from its base to the apex, and into the body of the os hyoides. Relations. — By its inner surface with its fellow of the opposite side. By its outer surface with the mylo-hyoideus, the hyo-glossus, the stylo- glossus, lingualis, the sublingual gland, the lingual artery, and the hypo- glossal nerve. By its upper border with the mucous membrane of the floor of the mouth, in the situation of the fraenum linguae; and by the lower border with the genio-hyoideus. Actions.—The whole of this group of muscles acts upon the os hyoides when the lower jaw is closed, and upon the lower jaw when the os hyoides is drawn downwards, and fixed by the depressors of the os hyoides and larynx. The genio-hyo-glossus is, moreover, a muscle of the tongue; its action upon that organ shall be considered with the next group. MUSCLES OF THE TONGUE. 191 Fourth Group.—Muscles ofthe Tongue. Genio-hyo-glossus, Stylo-glossus, Hyo-glossus, Palato-glossus. Lingualis, These are already exposed by the preparation we have just made ; there remains, therefore, only to dissect and examine them. The Genio-hyo-glossus, the first of these muscles, has been described with the last group. The Hvo-glossus is a square-shaped plane of muscle, arising from the whole length of the great cornu and from the body of the os hyoides, and inserted between the stylo-glossus and lingualis into the side of the tongue. The direction of the fibres of that portion of the muscle which arises from the body is obliquely backwards ; and that from the great cornu obliquely forwards; hence they are described by Albinus as two distinct muscles, under the names of the basio-glossus, and cerato-glossus, to which he added a third fasciculus, arising from the lesser cornu, and spreading along the side of the tongue, the chondro-glossus. The basio-glossus slightly overlaps the cerato-glossus at its upper part, and is separated from it by the transverse portion of the stylo-glossus. Relations.—By its external surface Fig. no.* with the digastric muscle, the stylo- hyoideus, stylo-glossus, and mylo- hyoideus, with the gustatory nerve, the hypoglossal nerve, Wharton's duct and the sublingual gland. By its internal surface with the middle constrictor of the pharynx, the lingualis, the genio- hyo-glossus, the lingual artery, and the glosso-pharyngeal nerve. The Lingualis.—The fibres of this muscle may be seen towards the apex of the tongue, issuing from the interval between the hyo-glossus and genio- hyo-glossus ; it is best examined by removing the preceding muscle. It consists of a small fasciculus of fibres, running longitudinally from the base, where it is attached to the os hyoides, to the apex of the tongue. It is in re- lation by its under surface with the ranine artery. * The styloid muscles and the muscles of the tongue. 1. A portion of the temporal bone ofthe left side of the skull, including the styloid and mastoid processes, and the meatus auditorius externus. 2, 2. The right side of the lower jaw, divided at its sym- physis; the left side having been removed. 3. The tongue. 4. The genio-hyoideus muscle. 5. The genio-hyo-glossus. 6. The hyo-glossus muscle, its basio-glossus portion. 7. Its cerato-glossus portion. 8. The anterior fibres of the lingualis issuing from between the hyo-glossus and genio-hyo-glossus. 9. The stylo-glossus muscle, with a small portion of the stylo-maxillary ligament. 10. The stylo-hyoid. 11. The stylo-pharyngeus muscle. 12. The os hyoides. l.'l. The thyro-hyoidean membrane. 14. The thyroid cartilage. 15. The thyro-hyoideus muscle arising from the oblique line on the thyroid cartilage. IC. The cricoid cartilage. 17. The crico-thyroidean membrane, through which the ope- ration of laryngotomy is performed. 18. The trachea. 19. The commencement of thf! oesophagus. 192 MUSCLES OF THE PHARYNX. The Stylo-glossus arises from the apex of the styloid process, and from the stylo-maxillary ligament; it divides upon the side of the tongue into two portions, one transverse, which passes transversely inwards be- tween the two portions of the hyo-glossus, and is lost among the transvei.se fibres of the substance of the tongue, and another longitudinal, which spreads out upon the side of the tongue as far as its tip. Relations.—By its external surface with the internal pterygoid muscle, the gustatory nerve, the parotid gland, sublingual gland, and the mucous membrane of the floor of the tongue. By its internal surface with the tonsil, the superior constrictor muscle of the pharynx, and the hyo-glossus muscle. The Palato-glossus passes between the soft palate, and the side of the base ofthe tongue, forming a projection of the mucous membrane, which is called the anterior pillar of the soft palate. Its fibres are lost superiorly among the muscular fibres ofthe palato-pharyngeus, and inferiorly among the fibres of the stylo-glossus upon the side of the tongue. This muscle with its fellow constitutes the constrictor isthmi faucium. Actions.—The genio-hyo-glossus muscle effects several movements of the tongue, as might be expected from its extent. When the tongue is steadied and pointed by the other muscles, the posterior fibres of the genio- hyo-glossus would dart it from the mouth, while its anterior fibres would restore it to its original position. The whole length of the muscle acting upon the tongue, would render it concave along the middle line, and form a channel for the current of fluid towards the pharynx, as in sucking. The apex of the tongue is directed to the roof of the mouth, and rendered con- vex from before backwards by the linguales. The hyo-glossi, by drawing down the sides of the tongue, render it convex along the middle line. It is drawn upwards at its base by the palato-glossi, and backwards or to either side by the stylo-glossi. Thus the whole of the complicated move- ments of the tongue may be explained, by reasoning upon the direction of the fibres of the muscles, and their probable actions. The palato-glossi muscles, assisted by the uvula, have the powrer of closing the fauces com- pletely, an action which takes place in deglutition. Fifth Group.—Muscles ofthe Pharynx. Constrictor inferior, Constrictor medius, Constrictor superior, Stylo-pharyngeus, Palato-pharyngeus. Dissection.—To dissect the pharynx, the trachea and oesophagus are to De cut through at the lower part of the neck, and drawn upwards by di- viding the loose cellular tissue which connects the pharynx to the vertebral column. The saw is then to be applied behind the styloid processes, and the base of the skull sawn through. The vessels and loose structure should be removed from the preparation, and the pharynx stuffed with towT or wool for the purpose of distending it, and rendering the muscle more easy of dissection. The pharynx is invested by a proper pharyngeal fascia. The Constrictor Inferior, the thickest of the three muscles of this class, arises from the upper rings of the trachea, the cricoid cartilage, and the oblique line of the thyroid. Its fibres spread out and are inserted into CONSTRICTOR SUPERIOR--STYLO-PHARYNGEUS. 193 the fibrous raphe of the middle of the pharynx, the inferior fibres being almost horizontal, and the superior oblique, and overlapping the middle constrictor. Relations.—By its external surface with the anterior surface of the ver- tebral column, the longus colli, the sheath of the common carotid artery, the sterno-thyroid muscle, the thyroid gland, and some lymphatic glands. By its internal surface with the middle constrictor, the stylo-pharyngeus, the palato-pharyngeus, and the mucous membrane of the pharynx. By its lower border, near the cricoid cartilage, it is in relation with the recurrent nerve ; and by the upper border with the superior laryngeal nerve. The fibres of origin of this muscle are blended with those of the sterno-hyoid, sterno-thyroid, and crico-thyroid, and it frequently forms a tendinous arch across the latter. This muscle must be removed before the next can be examined. The Constrictor Medius arises from the great cornu of the os hyoides, from the lesser cornu, and from the stylo-hyoidean ligament. It radiates from its origin upon the side of the pharynx, the lower fibres descending and being overlapped by the constrictor inferior, and the upper fibres ascending so as to cover in the constrictor superior. It is inserted into the raphe and by a fibrous aponeurosis into the basilar process of the occipital bone. Relations. — By its external surface with the vertebral column, the longus colli, rectus anticus major, the carotid vessels, inferior constrictor, hyo- glossus muscle, lingual artery, pharyngeal plexus of nerves, and some lymphatic glands. By its internal surface, with the superior constrictor, stylo-pharyngeus, palato-pharyngeus, and mucous membrane of the pha- rynx. The upper portion of this muscle must be turned down, to bring the whole ofthe superior constrictor into view ; in so doing, the stylo-pharyn- geus muscle will be seen passing beneath its upper border. The Constrictor Superior is a thin and quadrilateral plane of muscu- lar fibres arising from the extremity of the molar ridge of the lower jaw, from the pterygo-maxillary ligament, and from the lower half of the inter- nal pterygoid plate, and inserted into the raphe and basilar process of the occipital bone. Its superior fibres are arched and leave an interval be- tween its upper border and the basilar process, which is deficient in mus- cular fibres, and it is overlapped inferiorly by the middle constrictor. Between the side of the pharynx and the ramus of the lower jaw is a triangular interval, the maxillo-pharyngeal space, which is bounded on the inner side by the superior constrictor muscle; on the outer side by the internal pterygoid muscle; and behind by the rectus anticus major and vertebral column. In this space are situated the internal carotid artery, the internal jugular vein, and the glosso-pharyngeal, pneumogastric, spinal accessory, and hypo-glossal nerve. # Relations.__By its external surface with the vertebral column and its muscles behind; with the vessels and nerves contained in the maxillo- pharyno-eal space laterally, the middle constrictor,_ stylo-pharyngeus, and tensor palati muscle. By its internal surface with the levator palati, palato-pharyngeus, tonsil, and mucous membrane of the pharynx, the pharyngeal'fascia being interposed. The Stylo-pharyngeus is a long and slender muscle arising from the inner side of the base of the styloid process; it descends between the 194 MUSCLES OF THE SOFT PALATE. Fig. m * superior and middle constrictor muscles, and spreads out beneath the mucous membrane of the pharynx, its inferior fibres being in. serted into the posterior border of the thyroid cartilage. Relations. — By its external surface with the stylo-glossus muscle, external carotid artery, parotid gland, and the middle con- strictor. By its internal surface with the internal carotid artery, internal jugular vein, superior constrictor, palato-pharyngeus, and mucous membrane. Along its lower border is seen the glosso-pharyngeal nerve which ' crosses it, opposite the root of the tongue, to pass between the superior and middle con- , strictor and behind the hyo-glossus. The palato-pharyngeus is > described with the muscles of the soft palate. It arises from the soft palate, and is inserted into the inner surface of the pharynx, and posterior border of the thyroid cartilage. Actions.—The three constrictor muscles are important agents in deglu- tition ; they contract upon the morsel of food as soon as it is received by the pharynx, and convey it downwards into the oesophagus. The stylo- pharyngei draw the pharynx upwards and widen it laterally. The palato- pharyngei also draw it upwTards, and with the aid of the uvula close the opening of the fauces. Sixth Group.—Muscles ofthe Soft Palate. Levator palati, Tensor palati, Azygos uvulae, Palato-glossus, Palato-pharyngeus. Dissection. — To examine these muscles, the pharynx must be opened from behind, and the mucous membrane carefully removed from off the posterior surface of the soft palate. The Levator Palati, a moderately thick muscle, arises from the ex- tremity of the petrous bone and from the posterior and inferior aspect of the Eustachian tube, and passing down by the side of the posterior nares spreads out in the structure of the soft palate as far as the middle line. Relations.—-Externally with the tensor palati and superior constrictor muscle; internally and posteriorly with the mucous membrane of the pharynx and soft palate; and by its lower border with the palato-pha- ryngeus. * A side view of the muscles of the pharynx. 1. The trachea. 2. The cricoid car- tilage. 3. The crico-thyroid membrane. 4. The thyroid cartilage. 5. The thyro-hyoi- dean membrane. 6. The os hyoides. 7. The stylo-hyoidean ligament. 8. The oeso- phagus. 9. The inferior constrictor. 10. The middle constrictor. 11. The superior constrictor. 12. The stylo-pharyngeus muscle passing down between the superior and middle constrictor. 13. The upper concave border of the superior constrictor; at this point the muscular fibres of the pharynx are deficient. 14. The pterygo-maxillary liga- ment. 15. The buccinator muscle. 16. The orbicularis oris. 17. The mylo-hyoideus. PALATO-GLOSSUS--PALATO-PHARYNGEUS. 195 This muscle must be turned down from its origin on one side, and removed, and the superior constrictor dissected away from its pterygoid origin, to bring the next muscle into view. The- Tensor Palati (circumflexus) is a slender and flattened muscle ; it arises from the scaphoid fossa at the base of the inter- nal pterygoid plate and from the anterior aspect ofthe Eustachian tube. It descends to the hamular process, around which it turns and expands into a tendinous aponeu- rosis, which is inserted into the transverse 'tidgfi^pn the horizontal portion of the palate bone, and into the raphe. Relations.—By its external surface with the internal pterygoid muscle ; by its internal surface with the levator palati, internal pterygoid plate, and superior constrictor. In the soft palate, its tendinous expansion is placed in front of the other muscles and in contact with the mucous mem- brane. The Azygos Uvulje is not a single muscle, as might be inferred from its name, but a pair of small muscles placed side by side in the middle line ofthe soft palate. They arise from the spine ofthe palate bone, and are inserted into the uvula. By their anterior surface they are connected with the tendinous expansion of the levatores palati, and by the posterior with the mucous membrane. The two next muscles are brought into view throughout the whole of their extent, by raising the mucous membrane from off the pillars of the soft palate at each side. The Palato-glossus (constrictor isthmi faucium) is a small fasciculus of fibres that arises in the soft palate, and* descends to be inserted into the side ofthe tongue. It is the projection of this small muscle, covered by mucous membrane, that forms the anterior pillar of the soft palate. It has been named constrictor isthmi faucium from a function it performs in common with the palato-pharyngeus, viz. of constricting the opening of the fauces. The Palato-pharyngeus forms the posterior pillar of the fauces; it arises by an expanded fasciculus from the lower part of the soft palate, where its fibres are continuous with those of the muscle of the opposite * The muscles of the soft palate. 1. A transverse section through the middle of the base of the skull, dividing the basilar process of the occipital bone in the middle line, and the petrous portion of the temporal bone at each side. 2. The vomer covered by mucous membrane and separating the two posterior nares. 3, 3. The Eustachian tubes. 4. The levator palati muscle of the left side ; the right has been removed. 5. The ha miliar process of the internal pterygoid plate ofthe left side, around which the aponeu- rosis of the tensor palati is seen turning. 6. The pterygo-maxillary ligament. 7. The superior constrictor muscle of the left side, turned aside. S. The azygos uvulas muscle. 9. The internal pterygoid plate. 10. The external pterygoid plate. 11. The tensor pa- lati muscle. 12. Its aponeurosis expanding in the structure ofthe soft palate. 13. The external pterygoid muscle. 11. The attachments of two pairs of muscles cut short; the superior pair belong to the genio-hyo-glossi Tnuscles; the inferior pair to the genio- hyoidei. 15. The attachment ofthe mylo-hyoideus of one side and part of the opposite. 16. The anterior attachments ofthe digastric muscles. 17. The depression on the lower jaw corresponding with the submaxillary gland. The depression above the mylo-hyoi- deus on which the number 15 rests, corresponds with the situation of the sublingual gland. 196 PREVERTEBRAL MUSCLES. side ; and is inserted into the posterior border of the thyroid cartilage. This muscle is broad above where it forms the whole thickness of the lower half of the soft palate, narrow in the posterior pillar, and again broad and thin in the pharynx where it spreads out previously to its insertion. Relations.—In the soft palate it is in relation with the mucous membrane both by its anterior and posterior surface ; above, with the muscular layer formed by the levator palati, and below with the mucous glands situated along the margin of the arch of the palate. In the posterior pillar of the palate, it is surrounded for two-thirds of its extent by mucous membrane. In the pharynx, it is in relation by its outer surface with the superior and middle constrictor muscles, and by its inner surface with the mucous membrane of the pharynx, the pharyngeal fascia being interposed. Actions.—The azygos uvulae shortens the uvula. The levator palati raises the soft palate, while the tensor spreads it out laterally so as to form a septum between the pharynx and posterior nares. Taking its fixed point from below, the tensor palati will dilate the Eustachian tube. The palato- glossus and pharyngeus constrict the opening ofthe fauces, and by draw- ing down the soft palate they serve to press the mass of food from the dorsum of the tongue into the pharynx. Seventh Group.—Pravertebral Muscles. Rectus anticus major, Rectus anticus minor, Scalenus anticus, Scalenus posticus, Longus colli. Dissection.—These muscles have already been exposed by the removal of the face from the anterior aspect of the vertebral column ; all that is further needed is the removal of-the fascia by wiiich they are invested. The Rectus Anticus Major, broad and thick above, and narrow and pointed below, arises from the anterior tubercles of the transverse processes of the third, fourth, fifth, and sixth cervical vertebrae, and is inserted into the basilar process of the occipital bone. Relations.—By its anterior surface with the pharynx, the internal carotid artery, internal jugular vein, superior cervical ganglion, sympathetic nerve, pneumogastric, and spinal accessory nerve. By its posterior surface with the longus colli, rectus anticus minor, and superior cervical vertebrae. The Rectus Anticus Minor arises from the anterior border of the la- teral mass of the atlas, and is inserted into the basilar process; its fibres being directed obliquely upwrards and inwards. Relations.—By its anterior surface with the rectus anticus major, and externally with the superior cervical ganglion of the sympathetic. By its posterior surface with the articulation ofthe condyle of the occipital bone with the atlas, and with the anterior occipito-atloid ligament. The Scalenus Anticus is a triangular muscle, as its name implies, situated at the root of the neck and appearing like a continuation of the rectus anticus major; it arises from* the anterior tubercles ofthe transverse processes of the third, fourth, fifth, and sixth cervical vertebrae, and is in- serted into the tubercle upon the inner border of the first rib. Relations. — By its anterior surface with the sterno-mastoid and omo- hyoid muscle, with the cervicalis superficialis and posterior scapular artery, SCALENUS POSTICUS--LONGUS COLLI. 197 Fig. 113-f with the phrenic nerve, and with the subclavian vein, by which it is se- parated from the subclavius muscle and clavicle. By its posterior surface with the nerves which go to form the brachial plexus, and below with the subclavian artery. By its inner side it is separated from the longus colli by the vertebral artery. Its relations with the subclavian artery and vein are very important, the vein being before and the artery behind the muscle. The Scalenus Posticus arises from the posterior tubercles of all the cervical ver- tebrae excepting the first. It is inserted by two fleshy fasciculi into the first and second ribs. The anterior (scalenus medius) of the two fasciculi is large, and occupies all the surface of the first rib between the groove for the subclavian artery and the tuberosity. The posterior (scalenus posticus) is small, and is attached to the second rib. Albinus and Soemmering make five scaleni. Relations. — By its anterior surface with the brachial plexus and subclavian artery; posteriorly with the levator anguli scapulae, cervicalis ascendens, transversalis colli, and sacro-lumbalis ; internally with the first in- tercostal muscle, the first rib, the inter- transverse muscles, and cervical vertebrae; and externally with the sterno-mastoid, omo- hyoid, supra-scapular and posterior scapu- lar arteries. The Longus Colli is a long and flat muscle, consisting of twro portions. The upper arises from the anterior tubercle of the atlas, and is inserted into the transverse processes of the third, fourth, and fifth cervical verte- brae. The lower portion arises from the bodies of the second and third, and transverse processes of the fourth and fifth, and passes down the neck. to be inserted into the bodies of the three lower cervical and three upper dorsal vertebrae. We should thus arrange these attachments in a tabular form:— Upper portion. Lower portion. Origin. Insertion. Atlas - - - < 3d, 4th, and 5th transverse processes. 2d and 3d bodies C 3 lower cervical vertebrae, bodies. 4th and 5th trans- < verse processes. ( 3 upper dorsal, bodies. In general terms, the muscle is attached to the bodies and transverse * In a subject dissected in the school of the Middlesex hospital during the winter of IS 11 by Mr. Joseph Rogers, the subclavian artery of the left side was placed with the vein in front of the scalenus anticus muscle. f The prevertebral group of muscles ofthe neck. 1. The rectus anticus major mus- cle. 2. The scalenus anticus. 3. The lower part of the longus colli of the right side ; it is concealed superiorly by the rectus anticus major. 4. The rectus anticus minor. 5. The upper portion of the longus colli muscle. 6. Its lower portion; the figure rests upon the seventh cervical vertebra. 7. The scalenus posticus. 8. The rectus lateralis of the left side. 9. One of the intertransversales muscles. 17* 198 MUSCLES OF THE BACK. processes of the five superior cervical vertebrae above, and to the bodies ofthe last three cervical and first three dorsal below. Relations. — By its anterior surface, with the pharynx, oesophagus, the sheath of the common carotid, internal jugular vein and pneumogastric nerve, the sympathetic nerve, inferior laryngeal nerve, and inferior thyroid artery. By its posterior surface it rests upon the cervical and upper dor- sal vertebrae. Actions.—The rectus anticus major and minor preserve the equilibrium of the head upon the atlas; and, acting conjointly with the longus colli, flex and rotate the head and the cervical portion of the vertebral column. The scaleni muscles, taking their fixed point from below, are flexors of the vertebral column; and, from above, elevators of the ribs, and there- fore inspiratory muscles. Eighth Group.—Muscles ofthe Larynx. These muscles are described with the anatomy of the larynx, in Chap- ter XL muscles of the trunk. The muscles of the trunk may be subdivided into four natural groups; viz. 1. Muscles of the back. 3. Muscles of the abdomen. 2. Muscles of the thorax. 4. Muscles of the perineum. 1. Muscles ofthe Back.—The region ofthe back, in consequence of its extent, is common to the neck, the upper extremities, and the abdomen. The muscles of which it is composed are numerous, and may be arranged into six layers. First Layer. (Cervical Group.) ri* ' • Cervicalis ascendens, T J ■ ' , Transversalis colli, Latissimus dorsi. rn u i ± -j 1 rachelo-mastoideus, Second Layer. Complexus. T i-i Fifth Layer. Levator anguli scapulae, /r. J . „ Rhomboideus minor, _ Vorsal Group.) Rhomboideus major. Semi-spina is dorsi, J oemi-spinahs colli. Third Layer. n (Cervical Group.) Rectus posticus major, Serratus posticus superior, Rectus posticus minor, Serratus posticus inferior, Rectus lateralis, Splenius capitis, Obliquus inferior, Splenius colli. Obliquus superior. „ Al , Sixth Layer. fourth Layer. ,T ,.„ , J Multifidus spinae, (Dorsal Group.) Levatores costarum, Sacro-lumbalis, Supra-spinales, Longissimus dorsi, Inter-spinales, Spinalis dorsi. Inter-transversales. MUSCLES OF THE BACK. 199 First Layer. Dissection. — The muscles of this layer are to be dissected by making an incision along the middle line of the back, from the tubercle on the occipital bone to the coccyx. From the upper point of this incision carry a second along the side of the neck, to the middle of the clavicle. Infe- riorly, an incision must be made from the extremity of the sacrum, along the crest of the ileum, to about its middle. For the convenience of dis- section, a fourth may be carried from the middle of the spine to the acro- mion process. The integument and superficial fascia, together, are to be dissected off the muscles, in the course of their fibres, over the whole of this region. The Trapezius muscle (trapezium, a quadrangle with unequal sides) arises from the superior curved line of the occipital bone, from the liga- mentum nuchae, supra-spinous ligament, and spinous processes of the last cervical and all the dorsal vertebrae. The fibres converge from these various points, and are inserted into the scapular third of the clavicle, the acromion process, and the whole length of the upper border of the spine of the scapula. The inferior fibres become tendinous near the scapula, and glide over the triangular surface at the posterior extremity of its spine, upon a bursa mucosa. When the trapezius is dissected on both sides, the two muscles resemble a trapezium, or diamond-shaped quadrangle, on the posterior part of the shoulders: hence the muscle was formerly named cucullaris (cucullus, a monk's cowl). The cervical and upper part of the dorsal portion of the muscle is tendinous at its origin, and forms, with the muscle of the opposite side, a kind of tendinous ellipse. ' . Relations. — By its superficial surface, with the integument and super- ficial fascia, to which it is closely adherent by its cervical portion, loosely by its dorsal portion. By its deep surface, from above downwards, with the complexus, splenius, levator anguli scapulae, supra-spinatus-, a small portion of the serratus posticus superior, rhomboideus minor, rhomboideus major, intervertebral aponeurosis which separates it from the erector spina), and with the latissimus dorsi. The anterior border of the cervical portion of this muscle forms the posterior boundary of the posterior tri- angle of the neck. The clavicular insertion of the muscle sometimes ad- vances to the middle of the clavicle, or as far as the outer border of the sterno-mastoid, and occasionally it has been seen to overlap the latter. This is a point of much importance to be borne in mind in the operation for ligature of the subclavian artery. The spinal accessory nerve passes beneath the anterior border, near to the clavicle, previously to its distribu- tion to the muscle. The ligamentum nucha is a thin cellulo-fibrous layer extended from the tubercle and spine of the occipital bone, to the spinous process of the seventh cervical vertebra, where it is continuous with the supra-spinous ligament. It is connected with the spinous processes of the rest of the cervical verteorae, with the exception of the atlas, by means of a small fibrous slip which is sent off by each. It is the analogue of an important elastic ligament in animals. The Latissimus Dorsi muscle covers the whole of the lower part of the back and loins. It arises from the spinous processes of the seven inferior dorsal vertebra1, from all the lumbar and sacral spinous processes, from the posterior third ofthe crest ofthe ilium, and from the three lower ribs; the 200 MUSCLES OF THE BACK. latter origin takes place by muscular slips, wlr indigitate with the ex- ternal oblique muscle of the abdomen. The ;es from this extensive Fig. ] 14* origin converge as they ascend, and cross the inferior angle ofthe scapula; they then cu ^ around the lower border of the teres major muscle, and terminate in a short quadrilateral tendon,f which lies in front of the tendon of the teres, and is inserted into the bicipital groove. A synovial bursa is interposed between the muscle and the lower angle of the scapula, and * The first and second and part of the third layer of muscles of the back; the first layer being shown upon the right, and the second on the left side. 1. The trapezius muse e. 2. The tendinous portion which, with a corresponding portion in the opposite muscle, forms the tendinous ellipse on the back of the neck. 3. The acromion process and spine of the scapula. 4. The latissimus dorsi muscle. 5. The deltoid 6 The muscles of the dorsum of the scapula, infra-spinatus, teres minor, and teres major. 7. 1 he external oblique muscle. 8. The gluteus medius. 9. The glutei maximi 10 The levator anguli scapula, 11. The rhomboideus minor. 12. The rhomboideus major Id. Ihe splenius capitis ; the muscle immediately above, and overlaid by the splenius sSpeneiuCs°?sP!™\ 'i' V? E^*™ COlli' ^ ^^ ^ the ""»»» ortf ?*£ boTeuTm^r T^^S^^TTzrthe lower border °f ^ .:| 1st Layer. Trapezius . . . \ Latissimus dorsi . < 2d Layer. Levator anguli sea-) pulae .... J Rhomboideus mi- < nor ...._( Rhomboideus major 3d Layer. Serratus posticus superior . . Serratus posticus 5 inferior . , . ( Splenius capitis Splenius colli ith Layer. Sacro-lumbalis . . Accessorius ad sa-) cro-lumbalem . J Longissimus dorsi . Spinalis dorsi . . ^ Cervicalis ascendens Transversalis colli . Trachelo-mastoideus Complexus . . . 5th Layer. Semi-spinalis dorsi Semi-spinalis colli Rectus posticus ma jor . . . . Rectus posticus mi nor .... Rectus lateralis Obliquus inferior Obliquus superior 6th Layer. Multifidus spinae . Levatores costarum Supra-spinales . . Inter-spinales . .< Inter-transversales Spinous Processes. last cervical, 12 dorsal 6 lower dorsal, 5 lumbar lig. nucha? and last cervical 4 upper dorsal lig. nuchae, last cervical, 2 upper dorsal 2 lower dorsal, 2 upper lumbar lig. nucha?, last cervical, 6 upper dorsal 2 lower dorsal, 2 upper lumbar axis atlas cervical Cervical and lumbar Transverse Pro- cesses. 4 upper cervical • ■{ 3d, 4th, 5th, and 6th dorsal 4 upper dorsal, 4 lower cervical 4 upper dorsal, 4 lower cervical 6 lower dorsal 4 upper dorsal atlas atlas from sacrum to 3d cervical last cervical and eleven dorsal cervical and lumbar 3 lower angles of 6 lower angles 4 of upper Additional. occipital bone and / ligamentum nucha? \ sacrum and ilium . sacrum and ilium . sacrum and lumbar? vertebrae . 5 OF THE MUSCLES OF THE BACK. 209 INSERTION. Spinous Processes. Transverse Processes. Ribs. Additional. upper dorsal. 4 upper cervical 2d, 3d, 4th, and 5th. 4 lower ribs. . . . .{ angles of 6 lower. angles of 6 upper. all the ribs between the tubercles and angles. 4 lower cervical. 4 lower cervical. (4 upper dorsal, ) 2 lower cervical. \i upper cervical, ( except atlas. atlas. ifrom last lumbar to axis. cervical. cervical and lumbar. • i cervical and lumbar. all the ribs between the tubercles and angles. clavicle and spine of the scapula. posterior bicipital ridge of the humerus. angle and base of the scapula. base of the scapula. base of the scapula. occipital and mastoid portion of temporal bone. mastoid process. occipital bone between the curved lines. occipital bone. occipital bone. occipital bone. occipital bone. 18 210 MUSCLES OF THE THORAX. insertion, by distinct tendons, into the ribs and spinous processes. Being made up of a number of distinct fasciculi, which alternate in their actions, the spine is kept erect without fatigue, even when they have to counter- balance a corpulent abdominal development. The continuations upwards of these muscles into the neck preserve the steadiness and uprightness of that region. When the muscles of one side act alone, the neck is rotated upon its axis. The complexus, by being attached to the occipital bone, draw's the head backw-ards, and counteracts the muscles on the anterior part ofthe neck. It assists also in the rotation ofthe head. The semi-spinales and multifidus spina muscles act directly on the ver- tebrae, and contribute to the general action of supporting the vertebral column erect. The four little muscles situated between the occiput and the two first vertebrae, effect the various movements between these bones; the reck producing the antero-posterior actions, and the obliqui the rotatory mo- tions of the atlas on the axis. The actions of the remaining muscles of the spine, the supra and inter- spinales and inter-transversales, are expressed in their names. They ap- proximate their attachments and assist the more powerful muscles in pre- serving the erect position of the body. The levatores costarum raise the posterior parts of the ribs, and are probably more serviceable in preserving the articulation of the ribs from dislocation, than in raising them in inspiration. MUSCLES OF THE THORAX. The principal muscles situated upon the thorax belong in their actions to the upper extremity, with which they will be described. They are the pectoralis major and minor, subclavius and serratus magnus. The true thoracic muscles are few in number, and appertain exclusively to the ac- tions of the ribs; they are, the— Intercostales externi, Intercostales interni, Triangularis sterni. The intercostal muscles are two planes of muscular and tendinous fibres directed obliquely between the adjacent ribs and closing the inter- costal spaces. They are seen partially upon the removal of the pectoral muscles, or upon the inner surface of the chest. The triangularis sterni is within the chest, and requires the removal of the anterior part of the thorax to bring it into view. The Intercostales Externi, eleven on each side, commence poste- riorly at the tubercles of the ribs, and advance forwards to the costal car- tilages, where they terminate in a thin aponeurosis, which is continued onwards to the sternum. Their fibres are directed obliquely downwards and inwards, pursuing the same line with those of the external oblique muscle of the abdomen. They are thicker than the internal intercostals. The Intercostales Interni, also eleven on each side, commence ante- riorly at the sternum, and extend backwards as far as the angles of the ribs, whence they are prolonged to the vertebral column by a thin apo- neurosis. Their fibres are directed obliquely downwards and backwards, and correspond in direction with those of the internal oblique muscle of MUSCLES OF THE ABDOMEN. 211 the abdomen. The two muscles cross each other in the direction of their fibres. In structure the intercostal muscles consist of an admixture of muscular and tendinous fibres. They arise from the two lips of the lower border of the ribs, the external from the outer lip, the internal from the inner, and are inserted into the upper border. Relations.—The external intercostals, by their external surface, with the muscles which immediately invest the chest, viz. the pectoralis major and minor, the serratus magnus, serratus posticus superior and inferior, scalenus posticus ; sacro-lumbalis, and longissimus dorsi, with their continuations, the cervicalis ascendens and transversalis colli; the levatores costarum, and the obliquus externus abdominis. By their internal surface with the internal intercostals, the intercostal vessels and nerves, and a thin aponeu- rosis, and posteriorly with the pleura. The internal intercostals, by their external surface with the external intercostals, and intercostal vessels and nerves ; by their internal surface with the pleura costalis, the triangularis sterni and diaphragm. Connected with the internal intercostals are a variable number of mus- cular fasciculi, which pass from the inner surface of one rib near its middle to the next or next but one below; these are the subcostal, or more cor- rectly the intracostal muscles. The Triangularis Sterni, situated upon the inner wall ofthe front of the chest, arises by a thin aponeurosis from the side of the sternum, ensi- form cartilage, and sternal extremities of the costal cartilages; and is in- serted by fleshy digitations into the cartilages of the third, fourth, fifth and sixth ribs, and often into that ofthe second. Relations.—By its external surface with the sternum, the ensiform carti- lage, the costal cartilages, internal intercostal muscles, and internal mam- mary vessels. By its internal surface with the pleura costalis, the areolar tissue of the anterior mediastinum and the diaphragm. The lower fibres of the triangularis sterni are continuous with those of the diaphragm. Actions.—The intercostal muscles raise the ribs when they act from above, and depress them when they take their fixed point from below. They are, therefore, both inspiratory and expiratory muscles. The trian- gularis sterni draws down the costal cartilages, and is, therefore, an expi- ratory muscle. MUSCLES OF THE ABDOMEN. The muscles of this region are, the— Obliquus externus (descendens), Obliquus internus (ascendens), Cremaster, Transversalis, Rectus, Pyramidalis, Quadratus lumborum, Psoas parvus, Diaphragm. Dissection.—The dissection ofthe abdominal muscles is to be commenced by makino- three incisions:—The first, vertical, in the middle line, from over the lower part of the sternum to the pubes; the second oblique, from 212 MUSCLES OF THE ABDOMEN. the umbilicus, upwards and outwards, to the outer side of the chest, as high as the fifth or sixth rib ; and the third, oblique, from the umbilicus, downwards and outwards, to the middle of the crest of the ilium. The three flaps included by these incisions should then be dissected back in the direction of the fibres of the external oblique muscle, beginning at the angle of each. The integument and superficial fascia should be dissected off together so as to expose the fibres ofthe muscle at once. If the external oblique muscle be dissected on both sides, a white ten- dinous line will be seen along the middle ofthe abdomen, extending from the ensiform cartilage to the os pubis ; this is the linea alba. A little ex- ternal to it, on each side, two curved lines will be observed extending from the sides of the chest to the os pubis, and bounding the recti muscles: these are the linea semilunares. Some transverse lines, linea transversa, three or four in number, connect the lineae semilunares with the linea alba. The External Oblique Muscle (obliquus externus abdominis descendens) is the external flat muscle of the abdomen. Its name is derived from the obliquity of its direction, and the descending course of its fibres. It arises by fleshy digitations from the external surface of the eight inferior ribs; the five upper digitations being received between corresponding pro- cesses ofthe serratus magnus, and the three lower of the latissimus dorsi. Soon after its origin it spreads out into a broad aponeurosis, winch is in- serted into the outer lip of the crest of the ilium for one half its length, the anterior superior spinous process ofthe ilium, spine ofthe os pubis, pecti- neal line, front ofthe os pubis, and linea alba. The lower border of the aponeurosis, which is stretched between the anterior superior spinous process of the ilium and the spine of the os pubis, is rounded from being folded inwards, and forms PouparVs ligament; the insertion into the pectineal line is GimbernaVs ligament. Just above the crest of the os pubis is the external abdominal ring, a triangular opening formed, by the separation of the fibres ofthe aponeuro- sis ofthe external oblique. It is oblique in its direction, and corresponds with the course of the fibres of the aponeurosis. It is bounded below by the crest of the os pubis ; on either side by the borders of the aponeurosis, which are called pillars; and above by some curved fibres (inter-colum- nar), which originate from Poupart's ligament, and cross the upper angle of the ring so as to give it strength. The external pillar, which is at the same time inferior from the obliquity of the opening, is inserted into the spine of the os pubis ; the internal or superior pillar forms an interlacement with its fellow of the opposite side over the front of the symphysis pubis. The external abdominal ring gives passage to the spermatic cord in the male and round ligament in the female: they are both invested in their passage through it by a thin fascia derived from the edges ofthe ring, and called inter-columnar fascia, or fascia spermatica. The pouch of inguinal hernia, in passing through this opening, receives the inter-columnar fascia, as one of its coverings. Relations.—By its external surface with the superficial fascia and inte- gument, and with the cutaneous vessels and nerves, particularly the super- ficial epigastric and superficial circumflexa ilii vessels. It is generally overlapped posteriorly by the latissimus dorsi. By its internal surface with the internal oblique, the lower part of the eight inferior ribs and in- tercostal muscles, the cremaster, the spermatic cord in the male, and the MUSCLES OF THE ABDOMEN. 213 round ligament in the female. The upper border of the external oblique is continuous with the pectoralis major. The external oblique is now to be removed by making an incision across the ribs, just below its origin, to its posterior border; and another along Poupart's ligament and the crest of the ilium. Poupart's ligament Fig. 116.* * The muscles of the anterior aspect of the trunk; on the left side the superficial layer is seen, and on the right the deeper layer. 1. The pectoralis major muscle. 2. The deltoid; the interval between these muscles lodges the cephalic vein. 3. The an- terior border of the latissimus dorsi. 4. The serrations of the serratus magnus. 5. The subclavius muscle of the right side. 6. The pectoralis minor. 7. The coracho-brachia- lis muscle. 8. The upper part of the biceps muscle, showing its two heads. 9. The coracoid process of the scapula. 10. The serratus magnus of the right side. ' 11. The external intercostal muscle of the fifth intercostal space. 12. The external oblique mu>cle. 13. Its aponeurosis; the median line to the right of this number is the linea alba; the flexuous line to its left is the linea semilunaris; and the transverse lines above and below the number, the linese transversa?. 14. Poupart's ligament. 15. The external abdominal ring; the margin above the ring is the superior or internal pillar; the margin below the ring, the inferior or external pillar; the curved intercolumnar fibres are seen proceeding upwards from Poupart's ligament to strengthen the ring. The numbers 14 and 15 are situated upon the fascia lata ofthe thigh ; the opening im- mediately to the right of 15 is the saphenous opening. 16. The rectus muscle of the right side brought into view by the removal ofthe anterior segment of its sheath : * the posterior segment of its sheath with the divided edge of the anterior segment. 17. The pyramidalis muscle. 18. The internal oblique muscle. 19. The conjoined ten- don of the internal oblique and transversalis descending behind Poupart's ligament to the pectineal line. 20. The arch formed between the lower curved border of the interna1 oblique muscle and Poupart's ligament; it is beneath this arch that the sperm- atic cord and hernia pass. 214 MUSCLES OF THE ABDOMEN. should be left entire, as it gives attachment to the next muscles. The muscle may then be turned forwards towards the linea alba, or removed altogether. The Internal Oblique Muscle (obliquus internus abdominis ascendens) is the middle flat muscle of the abdomen. It arises from the outer half of Poupart's ligament, from the middle of the crest of the ilium for two- thirds of its length, and by a thin aponeurosis from the spinous processes of the lumbar vertebrae. Its fibres diverge from their origin, so that those from Poupart's ligament curve downwards, those from the anterior part of the crest of the ilium pass transversely, and the rest ascend obliquely. The muscle is inserted into the pectineal line and crest of the os pubis, linea alba, and lower borders of the five inferior ribs. Along the upper three-fourths of the linea semilunaris, the aponeurosis of the internal oblique separates into two lamellae, which pass one in front and the other behind the rectus muscle to the linea alba, where they are inserted ; along the lower fourth, the aponeurosis passes altogether in front of the rectus without separation. The two layers, which thus enclose the rectus, form for it a partial sheath. The lowest fibres of the internal oblique are inserted into the pectineal line of the os pubis in common with those of the transversalis muscle. Hence the tendon of this insertion is called the conjoined tendon ofthe in- ternal oblique and transversalis. This structure corresponds with the external abdominal ring, and forms a protection to what would otherwise be a weak point in the abdomen. Sometimes the tendon is insufficient to resist the pressure from within, and becomes forced through the external ring ; it then forms the distinctive covering of direct inguinal hernia. The spermatic cord passes beneath the arched border of the internal oblique muscle, between it and Poupart's ligament. During its passage some fibres are given off from the lowrer border of the muscle, which ac- company the cord downw7ards to the testicle, and form loops around it: this is the cremaster muscle. In the descent of oblique inguinal hernia, which travels the same course with the spermatic cord, the cremaster muscle forms one of its coverings. The Cremaster, considered as a distinct muscle, arises from the mid- dle of Poupart's ligament, and forms a series of loops upon the spermatic cord. A few of its fibres are inserted into the tunica vaginalis, the rest ascend along the inner side ofthe cord, to be inserted, with the conjoined tendon, into the pectineal line of the os pubis. Relations.—The internal oblique is in relation, by its external surface, with the external oblique, latissimus dorsi, spermatic cord, and external abdominal ring. By its internal surface, with the transversalis muscle, the fascia transversalis, the internal abdominal ring, and spermatic cord. By its lower and arched border, with the spermatic cord, forming the upper boundary of the spermatic canal. The cremaster is in relation, by its external surface, with the aponeuro- sis of the external oblique and intercolumnar fascia; and by its internal surface, with the fascia propria of the spermatic cord. The internal oblique muscle is to be removed by separating it from its attachments to the ribs above, and to the crest of the ilium and Poupart's ligament below. It should be divided behind by a vertical incision, ex- tending from the last rib to the crest of the ilium, as its lumbar attachment cannot at present be examined. The muscle is then to be turned for- TRANSVERSALIS. 215 wards. Some degree of care will be required in performing this dissec- tion, from the difficulty of distinguishing between this muscle and the one beneath. A thin layer of cellular tissue is all that separates them for the greater part of their extent. Near the crest of the ilium, the circumflexa ilii artery ascends between the two muscles, and forms a valuable guide to their separation. Just above Poupart's ligament they are so closely connected, that it is impossible to divide them. The Transversalis is the internal flat muscle of the abdomen; it is transverse in the direction of its fibres, as is implied in its name. It arises from the outer third of Poupart's ligament, from the internal lip of the crest ofthe ilium, its anterior two-thirds ; from the spinous and transverse pro- cesses of the lumbar vertebrae, and from the inner surfaces of the six in- ferior ribs, indigitating with the diaphragm. Its lower fibres curve down- wards, to be inserted, with the lower fibres of the internal oblique, into the pectineal line, and form the conjoined tendon. Throughout the rest of its extent it is inserted into the crest of the os pubis and linea alba. The lower fourth of its aponeurosis passes in front of the rectus to the linea alba; the upper three-fourths with the posterior lamella of the internal oblique, behind it. The posterior aponeurosis of the transver- Fig. 117.* salis divides into three lamellae ;—anterior, which is attached to the bases of the trans- verse processes of the lumbar vertebrae; middle, to the apices of the transverse pro- cesses ; and posterior, to the apices of the spinous processes. The anterior and mid- dle lamellae enclose the quadratus lumborum muscle; and the middle and posterior, the erector spinae. The union of the posterior lamella of the transversalis with the poste- rior aponeurosis of the internal oblique, serratus posticus inferior, and latissimus dorsi, constitutes the lumbar fascia. Relations.—By its external surface with the internal oblique, the internal surfaces of the lower ribs, and internal intercostal muscles. By its internal surface with the transversalis fascia, which separates it from the peritoneum, with the psoas magnus, and with the lower part ofthe rectus and pyra- midalis. The spermatic cord and oblique inguinal hernia pass beneath the lower bor- der, but have no direct relation with it. * A lateral view of the trunk of the body, showing its muscles, and particularly the transversalis abdominis. 1. The costal oriirin of the latissimus dorsi muscle. 2. The serratus magnus. 3. The upper part of the external oblique muscle, divided in the di- rection host calculated to show the muscles beneath, without interfering with its indigi- tations with the serratus magnus. 4. Two ofthe external intercostal muscles. 5. Two of the internal intercostals. 6. The transversalis muscle. 7. Its posterior aponeurosis. 8. Its anterior aponeurosis, forming the most posterior layer of the sheath of the rectus. 0. The lower part ofthe left rectus, with the aponeurosis ofthe transversalis passing in front. 10. The right rectus muscle. 11. The arched opening left between the lower border of the transversalis muscle and Poupart's ligament, through which the spermatic cord and hernia pass. 12. The gluteus maximus, and medius, and tensor vaginas femo- ris muscles invested by fascia lata. 216 MUSCLES OF THE ABDOMEN. To dissect the rectus muscle, its sheath should be opened by a vertical incision extending from over the cartilages of the low-er ribs to the front of the os pubis. The sheath may then be dissected off and turned to either side ; this is easily done excepting at the lineae transversae, where a close adhesion subsists between the muscle and the external boundary of the sheath. The sheath contains the rectus and pyramidalis muscle. The Rectus Muscle arises by a flattened tendon from the crest of the os pubis, and is inserted into the cartilages of the fifth, sixth, and seventh ribs. It is traversed by several tendinous zigzag intersections, called lineae transversae. One of these is usually situated at the umbilicus, two above that point, and sometimes one below. They are vestiges of the abdominal ribs of reptiles, and very rarely extend completely through the muscle. Relations.—By its external surface with the anterior lamella of the apo- neurosis of the internal oblique, below with the aponeurosis of the trans- versalis, and pyramidalis. By its internal surface with the ensiform carti- lages ofthe fifth, sixth, seventh, eighth and ninth ribs, with the posterior lamella of the internal oblique, the peritoneum, and the epigastric artery and veins. The Pyramidalis Muscle arises from the crest of the os pubis in front of the rectus, and is inserted into the linea alba at about midway between the umbilicus and the os pubis. It is enclosed in the same sheath with the rectus, and rests against the lower part of that muscle.- This muscle is sometimes wanting. The rectus may now be divided across the middle, and the two ends drawn aside for the purpose of examining the mode of formation of its sheath. The sheath ofthe rectus is formed in front for the upper three-fourths of its extent, by the aponeurosis of the external oblique and the anterior la- mella of the internal oblique, and behind by the posterior lamella of the internal oblique and the aponeurosis of the transversalis. At the com- mencement of the lower fourth, the posterior wall of the sheath terminates in a thin curved margin, the aponeurosis of the three muscles passing alto- gether in front of the rectus. The next two muscles can be examined only when the viscera of the abdomen are removed. To see the quadratus lumborum, it is also neces- sary to divide and draw aside the psoas muscle and the anterior lamella of the aponeurosis of the transversalis. The Quadratus Lumborum muscle is concealed from view by the an- terior lamella of the aponeurosis of the transversalis muscle, which is in- serted into the bases of the transverse processes of the lumbar vertebrae. When this lamella is divided, the muscle will be seen arising from the last rib, and from the transverse processes of the four upper lumbar vertebrae. It is inserted into the crest of the ilium and ilio-lumbar ligament. If the muscle be cut across or removed, the middle lamella of the transversalis will be seen attached to the apices of the transverse processes; the qua- dratus being enclosed between the two lamellae as in a sheath. Relations.—Enclosed in the sheath formed by the transversalis muscle, it is in relation in front, with the kidney, the colon, the psoas magnus and the diaphragm. Behind, but also separated by a sheath, with the erector spinae. The Psoas Parvus arises from the tendinous arches and intervertebral DIAPHRAGM. 217 substance of the last dorsal and first lumbar vertebra, and terminates in a long slender tendon which expands inferiorly and is inserted into the ilio- pectineal line and eminence. The tendon is continuous by its outer bor- der with the iliac fascia. Relations.—-It rests upon the psoas magnus, and is covered in by the peritoneum ; superiorly it passes beneath the ligamentum arcuatum of the diaphragm. It is occasionally wanting. Diaphragm.—To obtain a good view of this important inspiratory muscle, the peritoneum should be dissected from its under surface. It is the muscular septum between the thorax and abdomen, and is composed of two portions, a greater and a lesser muscle. The greater muscle arises from the ensiform cartilage; from the inner surfaces of the six inferior ribs, indigitating with the transversalis ; and from the ligamentum arcua- tum externum and internum. From these points, which form the internal circumference of the trunk, the fibres converge and are inserted into the central tendon. The ligamentum arcuatum externum is the upper border of the anterior lamella of the aponeurosis of the transversalis: it arches across the origin of the quadratus lumborum muscle, and is attached by one extremity to the base of the transverse process of the first lumbar vertebra, and by the other to the apex and lower margin of the last rib. The ligamentum arcuatum internum, or proprium, is a tendinous arch thrown across the psoas magnus muscle as it emerges from the chest. It is attached by one extremity to the base of the transverse process of the first lumbar vertebra, and by the other is continuous with the tendon of the lesser muscle opposite the body of the second. The tendinous centre of the diaphragm is shaped like a trefoil leaf, of which the central leaflet points to the ensiform cartilage, and is the largest; the lateral leaflets, right and left, occupy the corresponding portions of the muscle; the right being the larger and more rounded, and the left smaller and lengthened in its form. Between the sides of the ensiform cartilage and the cartilages of the adjoining ribs, is a small triangular space where the muscular fibres of the diaphragm are deficient. This space is closed only by peritoneum on the side of the abdomen, and by pleura within the chest. It is therefore a weak point, and a portion of the contents of the abdomen might, by vio- lent exertion, be forced through it, producing phrenic, or diaphragmatic hernia. The lesser muscle of the diaphragm takes its origin from the bodies of the lumbar vertebrae by two tendons. The right, larger and longer than the left, arises from the anterior surface of the bodies of the second, third, and fourth vertebrae ; and the left from the side of the second and third. The tendons form two large fleshy bellies (crura), which ascend to be in- serted into the central tendon. The inner fasciculi of the two crura cross each other in front of the aorta, and again diverge to surround the oeso- phagus, so as to present the appearance of a figure of eight. The ante- rior fasciculus of the decussation is formed by the right cms. The openings in the diaphragm are three : one, quadrilateral, in the tendinous centre, at the union of the right and middle leaflets, for the passage of the inferior vena cava; a muscular opening of an elliptic shape formed by the two crura, for the transmission of the oesophagus and pneu- moa-astric nerves ; and a third, the aortic, which is formed by a tendinous 19 218 MUSCLES OF THE ABDOMEN. the convexity of the liver; and behind with the kidneys, the supra-renal capsules, the duodenum, and the solar plexus. By its circumference with the ribs and intercostal muscles, and with the vertebral column. Actions.—The external oblique muscle, acting singly, would draw the thorax towards the pelvis, and twist the body to the opposite side. Both muscles, acting together, would flex the thorax directly on the pelvis. The internal oblique of one side draws the chest downwards and outwards: both together bend it directly forwards. Either transversalis muscle, act- ing singly, will diminish the size of the abdomen on its own side, and both together will constrict the entire cylinder of the cavity. The recti muscles, assisted by the pyramidales, flex the thorax upon the chest, and, through the medium of the lineae transversae, are enabled to act when their sheath is curved inwards by the action of the transversales. The pyramidales are tensors ofthe linea alba. The abdominal are expiratory muscles, and the chief agents of expulsion ; by their action the foetus is expelled from the uterus, the urine from the bladder, the faeces from the rectum, the bile from the gall-bladder, the ingesta from the stomach and bowels in vomit- ing, and the mucous and irritating substances from the bronchial tubes, * The under or abdominal side of the diaphragm. 1, 2, 3. The greater muscle; the figure 1 rests upon the central leaflet of the tendinous centre ; the number 2 on the left or smallest leaflet; and number 3 on the right leaflet. 4. The thin fasciculus which arises from the ensiform cartilage; a small triangular space is left on either side of this fasciculus, which is closed only by the serous membranes of the abdomen and chest, 5. The ligamentum arcuatum externum of the left side. 6. The ligamentum arcuatum internum. 7. A small arched opening occasionally found, through which the lesser splanchnic nerve passes. 8. The right or larger tendon of the lesser muscle; a mus- cular fasciculus from this tendon curves to the left side of the greater muscle between the oesophageal and aortic openings. 9. The fourth lumbar vertebra. 10. The left oi shorter tendon of the lesser muscle. 11. The aortic opening occupied by the aorta, which is cut short off. 1'2. A portion ofthe oesophagus issuing through the oesophageal opening; in this figure the oesophageal opening is tendinous at its anterior part, a struc- ture which is not uncommon. 13. The opening for the inferior vena cava, in the ten- dinous centre of the diaphragm. 14. The psoas magnus muscle passing beneath the ligamentum arcuatum internum; it has been removed on the opposite side to show the arch more distinctly. 15. The quadratus lumborum passing beneath the ligamentum arcuatum externum ; this muscle has also been removed on the left side. MUSCLES OF THE PERINEUM. 219 trachea, and nasal passages, during coughing and sneezing. To produce these efforts they all act together. Their violent and continued action produces hernia; and, acting spasmodically, they may occasion rupture of the viscera. The quadratus lumborum draws the last rib downwards, and is an expiratory muscle ; it also serves to bend the vertebral column to one or the other side. The psoas parvus is a tensor of the iliac fascia, and, taking its fixed origin from below, it may assist in flexing the verte- bral column forwards. The diaphragm is an inspiratory muscle, and the sole agent in tranquil inspiration. When in action, the muscle is drawn downwards, its plane being rendered oblique from the level of the ensi- form cartilage, to that of the upper lumbar vertebra. During relaxation it is convex, and encroaches considerably on the cavity of the chest, par- ticularly at the sides, where it corresponds with the lungs. It assists the abdominal muscles powerfully in expulsion, every act of that kind being preceded or accompanied by a deep inspiration. Spasmodic action of the diaphragm produces hiccough and sobbing, and its rapid alternation of contraction and relaxation, combined with laryngeal and facial movements, laughing and crying. muscles of the perineum. The muscles of the perineum are situated in the outlet of the pelvis, and consist of two groups, one of which belongs especially to the organs of generation and urethra, the other to the termination of the alimentary canal. To these may be added the only pair of muscles which is proper to the pelvis, the coccygeus. The muscles of the perineal region in the male, are the Accelerator urinae, Erector penis, Compressor urethrae, Transversus perinei, Dissection.—To dissect the perineum, the subject should be fixed in the position for lithotomy, that is, the hands should be bound to the soles of the feet, and the knees kept apart. An easier plan is the drawing of * the feet upwards by means of a cord passed through a hook in the ceiling. Both of these plans of preparation have for their object the full exposure ofthe perineum. And as this is a dissection which demands some degree ■ of delicacy and nice manipulation, a strong light should be thrown upon the part. Having fixed the subject, and drawn the scrotum upwards by means of a string or hook, cany an incision from the base of the scrotum '. along the ramus of the pubes and ischium and tuberosity of the ischium, ; to a point parallel with the apex of the coccyx; then describe a curve over the coccyx to the same point on the opposite side, and continue the incision onwards along the opposite tuberosity, and along the ramus ofthe ischium and of the pubes, to the opposite side of the scrotum, wrhere the two extremities maybe connected by a transverse incision. This incision will completely surround the perineum, following very nearly the outline ; of its boundaries. Now let the student dissect oft' the integument care- fully from the whole of the included space, and he will expose the fatty .cellular structure of the common superficial fascia, which exactly resembles ■ the superficial fascia in ever)- other situation. The common superficial Sphincter ani, Levator ani, Coccygeus. 220 MUSCLES OF THE PERINEUM. fascia is then to be removed to the same extent, exposing the superficial perineal fascia. This layer is also to be turned aside, when the muscles of the genital region of the perineum will be brought into view. The Acceleratores Urinas (bulbo-cavernosus) arise from a tendinous point in the centre of the perineum and from the fibrous raphe of the two muscles. From these origins the fibres diverge, like the plumes of a pen; the posterior fibres to be inserted into the ramus of the pubes and ischium; the middle to encircle the corpus spongiosum, and meet upon its upper side ; and the anterior to spread out upon the corpus cavernosum on each side, and be inserted, partly into its fibrous structure, and partly into the fascia ofthe penis. The posterior and middle insertions of these muscles are best seen, by carefully raising one muscle from the corpus spongiosum and tracing its fibres. Relations.—By their superficial surface with the superficial perineal fascia, the dartos, the superficial vessels and nerves of the perineum, and on each side with the erector penis. By their deep surface with the corpus spongiosum and bulb of the urethra. The Erector Penis (ischio-cavernosus) arises from the ramus and tu- berosity of the ischium, and curves around the root of the penis, to be in- serted into the upper surface of the corpus cavernosum, where it is con- tinuous with a strong fascia which covers the dorsum of the organ, the fascia penis. Relations.—By its superficial surface with the superficial perineal fascia, the dartos, and the superficial perineal vessels and nerve. By its deep surface with the corpus cavernosum penis. The Compressor Urethje (Wilson's and Guthrie's muscles), consists of two portions ; one of which is transverse in its direction, and passes in- wards, to embrace the membranous urethra; the other is perpendicular, and descends from the pubes. The transverse portion, particularly de- scribed by Mr. Guthrie, arises by a narrow tendinous point, from the upper part of the ramus of the ischium, on each side, and divides into two fasci- culi, which pass inwards and slightly upwards, and embrace the membra- nous portion of the .urethra and Cowper's glands. As they pass towards the urethra, they spread out and become fan-shaped, and are inserted into a tendinous raphe upon the upper and low7er surfaces of the urethra, ex- tending from the apex of the prostate gland, to which they are attached posteriorly, to the bulbous portion of the urethra, with which they are con- nected in front. When seen from above, these portions resemble two fans, connected by their expanded border along the middle line of the mem- branous urethra, from the prostate to the bulbous portion of the urethra, The same appearance is obtained by viewing them from below. The perpendicular portion* described by Mr. Wilson, arises by two ten- dinous points from the inner surface of the arch of the pubes, on each side of, and close to, the symphysis. The tendinous origins soon become muscular, and descend perpendicularly, to be inserted into the upper fas- ciculus of the transverse portion of the muscle; so that it is not a distinct muscle surrounding the membranous portion of the urethra, and support- * Mr. Tyrrell, who made many careful dissections of the muscles of the perineum, did not observe this portion of the muscle ; he considers Wilson's muscle (with some other anatomists) to be the anterior fibres of the levator ani, not uniting beneath the urethra, as described by Mr. Wilson; but inserted into a portion of the pelvic fascia situated between the prostate gland and rectum, the recto-vesical fascia. TRANSVERSUS PERINEI. 221 ing it as in a sling, as described by Mr. Wilson, but merely an upper origin of the transverse muscle. Fig. 119* The compressor urethrae may be considered either as two symmetrical muscles meeting at the raphe, or as a single muscle: I have adopted the latter course in the above description, as appearing to me the more con- sistent with the general connexions of the muscle, and with its actions. The Transversus Perinei arises from the tuberosity of the ischium on each side, and is inserted into the central tendinous point of the perineum.f Relations.—By its superficial surface with the superficial perineal fascia, and superficial perineal artery. By its deep surface with the deep perineal fascia, and internal pudic artery and veins. By its posterior border it is in relation with that portion of the superficial perineal fascia which passes back to become continuous with the deep fascia. To dissect the compressor urethra, the whole of the preceding muscles should be removed, so as to render the glistening surface of the deep peri- neal fascia quite apparent. The anterior layer of the fascia should then be carefully dissected away, and the corpus spongiosum penis divided through its middle, separated from the corpus cavernosum, and drawn forwards, to put the membranous portion of the urethra, upon which the muscle is spread out, on the stretch. The muscle is, however, better seen in a dissection made from within the pelvis, after having turned * The muscles ofthe perineum. 1. The acceleratores urinae muscles; the figure rests upon the corpus spongiosum penis. 2. The corpus cavernosum of one side. 3. The erector penis of one side. 4. The transversus perinei of one side. 5. The triangular space through which the deep perineal fascia is seen. 6. The sphincter ani; its ante- rior extremity is cut oft". 7. The levator ani of the left side ; the deep space between the tuberosity ofthe ischium (8) and the anus, is the ischio-rectal fossa; the same fossa is seen upon the opposite side. 9. The spine of the ischium. 10. The left coccygeus muscle. The boundaries of the perineum are well seen in this engraving. f I have twice dissected a perineum in which the transversus perinei was of large size, and spread out as it approached the middle line, so as to become fan-shaped. The posterior fibres were continuous with those of the muscle of the opposite side ; but the anterior were prolonged forwards upon the bulb and corpus spongiosum of the urethra, as far as the middle of the penis, forming a broad layer which usurped the place and office of the accelerator urinae. 19* 222 MUSCLES OF THE PERINEUM. down the bladder from its attachment to the os pubis, and removed a plexus of veins and the posterior layer of the deep perineal fascia. The Sphincter Ani is a thin and elliptical plane of muscle closely ad- herent to the integument, and surrounding the opening of the anus. It arises posteriorly in Ihe superficial fascia around the coccyx, and by a fibrous raphe from the apex of that bone ; and is inserted anteriorly into the tendinous centre of the perineum, and into the raphe of the integument, nearly as far forwards as the commencement of the scrotum. Relations.—By its superficial surface with the integument. By its deep surface with the internal sphincter, the levator ani, the cellular tissue and fat in the ischio-rectal fossa, and in front with the superficial perineal fascia. ' The Sphincter Ani Internus is a muscular ring embracing the ex- tremity of the intestine, and formed by an aggregation of the circular fibres of the rectum. Part of the levator ani may be seen during the dissection of the anal J portion of the perineum, by removing the fat which surrounds the termi- | nation of the rectum in the ischio-rectal fossa. But to study the entire muscle, a lateral section of the pelvis must be made by sawing through i the pubes a little to one side of the symphysis, separating the bones behind at the sacro-iliac symphysis, and turning down the bladder and | rectum. The pelvic fascia is then to be carefully raised, beginning at the base of the bladder and proceeding upwards, until the whole extent of the muscle is exposed. The Levator Ani is a thin plane of muscular fibres, situated on each side of the pelvis. The muscle arises from the inner surface of the os pubis, from the spine of the ischium, and between those points from the angle of division between the obturator and the pelvic fascia. Its fibres descend, to be inserted, into the extremity of the coccyx, into a fibrous raphe in front of that bone, into the low7er part of the rectum, base of the bladder, and prostate gland. In the female, this muscle is inserted into the coccyx and fibrous raphe, lower part of the rectum and vagina. Relations.—By its external or perineal surface, with a thin layer of fascia, by which, and by the obturator fascia, it is separated from the ob- turator internus muscle ; with the fat in the ischio-rectal fossa, the deep perineal fascia, the levator ani, and posteriorly with the gluteus maximus. By its internal or pelvic surface, with the pelvic fascia, which separates it from the viscera of the pelvis and peritoneum. The Coccygeus Muscle is a tendino-muscular layer of triangular form. It arises from the spine of the ischium, and is inserted into the side of the coccyx and lower part of the sacrum. Relations.—By its internal or pelvic surface, with the rectum; by its external surface, with the lesser and greater sacro-ischiatic ligaments. The muscles of the perineum in the female are the same as in the male, and have received analogous names. They are smaller in size, and are modified to suit the different form of the organs; they are— Constrictor vaginae, Sphincter ani, Erector clitoridis, Levator ani, Transversus perinei, Coccygeus. Compressor urethrae, MUSCLES OF THE UPPER EXTREMITY. 223 The Constrictor vagina is analogous to the acceleratores urinae; it is continuous, posteriorly, with the sphincter ani, interlacing with its fibres, and is inserted, anteriorly, into the sides of the corpora cavernosa, and fascia of the clitoris. The Transversus perinei is inserted into the side of the constrictor vagi- nae, and the levator ani into the side of the vagina. The other muscles are precisely similar in their attachments to those in the male. Actions.—The acceleratores urinae being continuous at the middle line, and attached on each side to the bone, by means of their posterior fibres, will support the bulbous portion of the urethra, and acting suddenly, will propel the semen, or the last drops of urine, from the canal. The poste- rior and middle fibres, according to Krause,* contribute towards the erec- tion of the corpus spongiosum, by producing compression upon the venous structure of the bulb ; and the anterior fibres, according to Tyrrell,f assist in the erection of the entire organ by compressing the vena dorsalis, by means of their insertion into the fascia penis. The erector penis becomes entitled to its name from spreading out upon the dorsum of the organ, into a membranous expansion, (fascia penis,) which, according to Krause, compresses the dorsal vein during the action of the muscle, and especially after the erection of the organ has commenced. The transverse muscles serve to steady the tendinous centre, that the muscles attached to it may obtain a firm point of support. According to Cruveilhier, they draw7 the anus backwards during the expulsion of the faeces, and antagonize the levatores ani, which carry the anus forwards. The compressor urethrae, taking its fixed point from the ramus of the ischium at each side, can, says Mr. Guthrie, " compress the urethra so as to close it; I conceive completely, after the manner of a sphincter." The transverse portion will also have a tendency to draw the urethra downwards, whilst the perpen- dicular portion will draw it upwards towards the os pubis. The inferior fasciculus of the transverse muscle, enclosing Cow7per's glands, will assist those bodies in evacuating their secretion. The external sphincter, being a cutaneous muscle, contracts the integument around the anus, and by its attachment to the tendinous centre, and to the point of the coccyx, assists the levator ani in giving support to the opening during expulsive efforts. The internal sphincter contracts the extremity of the cylinder of the intes- tine. The use of the levator ani is expressed in its name. It is the an- tagonist of the diaphragm and the rest of the expulsory muscles, and series to support the rectum and vagina during their expulsive efforts. The levator ani acts in unison with the diaphragm, and rises and falls like that muscle in forcible respiration. Yielding to the propulsive action of the abdominal muscles, it enables the outlet ofthe pelvis to bear a greater force than a resisting structure, and on the remission of such action it re- stores the perineum to its original form. The coccygei muscles restore the coccyx to its natural position, after it has been pressed backwards during defaecation or during parturition. muscles of the upper extremity. The muscles of the upper extremity may be arranged into groups cor- responding with the different regions of the limb, thus: * Miiller, Archiv. fur Anatomie, Physiologie, &c. 1837. ■j- Lectures in the College of Surgeons. 1839. 224 MUSCLES OF THE UPPER EXTREMITY. Anterior Thoracic Region. Pectoralis major, Pectoralis minor, Subclavius. Anterior Scapular Region. Subscapularis. Lateral Thoracic Region. Serratus magnus. Posterior Scapular Region. Supra-spinatus, Infra-spinatus, Teres minor, Teres major. Acromial Region. Deltoid. Anterior Humeral Region. Coraco-brachialis, Biceps, Brachialis anticus. Anterior Brachial Region. Superficial Layer. Pronator radii teres, Flexor carpi radialis, Palmaris longus, Flexor sublimis digitorum, Flexor carpi ulnaris. Deep Layer. Flexor profundus digitorum. Flexor longus pollicis. Pronator quadratus. Radial Region (Thenar). Abductor pollicis, Flexor ossis metacarpi (opponens), Flexor brevis pollicis, Adductor pollicis. Posterior Humeral Region. Triceps. Posterior Brachial Region. Superficial Layer. Supinator longus, Extensor carpi radialis longior, Extensor carpi radialis brevior, Extensor communis digitorum, Extensor minimi digiti, Extensor carpi ulnaris, Anconeus. Deep Layer. Supinator brevis, Extensor ossis metacarpi pollicis, Extensor primi internodii pollicis, Extensor secundi internodii pollicis Extensor indicis. Hand. Ulnar Region (Hypothenar). Palmaris brevis, Abductor minimi digiti, Flexor brevis minimi digiti. Adductor minimi digiti. Palmar Region. Lumbricales, Interossei palmares, Interossei dorsales. Anterior Thoracic Region. Pectoralis major, Pectoralis minor, Subclavius. PECTORALIS MAJOR AND MINOR. 225 Dissection. — Make an incision along the line of the clavicle, from the jpper part of the sternum to the acromion process; a second along the lower border of the great pectoral muscle, from the lower end of the ster- num to the insertion of its tendon into the humerus, and connect the two by a third, carried longitudinally along the middle of the sternum. The integument and superficial fascia are to be dissected together from off the fibres ofthe muscle, and always in the direction of their course. For this purpose the dissector, if he have the right arm, will commence with the lower angle of the flap ; if the left, with the upper angle. He will thus expose the pectoralis major muscle in its wiiole extent. The Pectoralis Major muscle arises from the sternal two-thirds of the clavicle, from one half the breadth of the sternum its whole length, from the cartilages of all the true ribs, excepting the first and last, and from the aponeurosis of the external oblique muscle of the abdomen. It is inserted by a broad tendon into the anterior bicipital ridge of the hu- merus. That portion of the muscle which arises from the clavicle is separated from that connected with the sternum by a distinct cellular interspace; hence we speak of the clavicular portion and sternal portion of the pecto- ralis major. The fibres from this very extensive origin converge towards a narrow insertion, giving the muscle a radiated appearance. But there is a peculiarity about the formation of its tendon which must be carefully noted. The whole of the lower border is folded inwards upon the upper portion, so that the tendon is doubled upon itself. Another peculiarity results from this arrangement: the fibres ofthe upper portion ofthe mus.de are inserted into the lower part of the bicipital ridge; and those of the lower portion, into the upper part. Relations. — By its external surface with the fibres of origin of the platysma myoides, the mammary gland, the superficial fascia and inte- gument. By its internal surface, on the thorax, with the clavicle, the sternum, the costal cartilages, intercostal muscles, subclavius, pectoralis minor, and serratus magnus; in the axilla, with the axillary vessels and glands. By its external border with the deltoid, from which it is separated above by a cellular interspace lodging the cephalic vein and the descend- ing branch of the thoracico-acromialis artery. Its lower border forms the anterior boundary of the axillary space. The pectoralis major is now to be removed by dividing its fibres along the lower border of the clavicle, and then carrying the incision perpendi- cularly downwards, parallel to the sternum, and at about three inches from its border. Divide some loose cellular tissue, and several small branches of the thoracic arteries, and reflect the muscte outwardsl We thus bring into view a region of considerable interest, in the middle of which is situated the pectoralis minor. . The Pectoralis Minor arises by three digitations from the third, fourth, and fifth ribs, and is inserted into the anterior border of the coracoid pro- cess of the scapula by a broad tendon. # Relations —By its anterior surface with the pectoralis major and supe- rior thoracic vessels and nerves. By its posterior surface with the ribs, the intercostal muscles, serratus magnus, axillary space, and axillary vessels and nerves. Its upper border forms the lower boundary of a trian- gular space bounded above by the costo-coracoid membrane, and inter- 226 ANTERIOR SCAPULAR REGION. nally by the ribs. In this space are found the axillary vessels and nerves, and in it the subclavian artery may be tied below the clavicle. The Suhclavius muscle arises by a round tendon from the cartilage ofthe first rib, and is inserted into the under surface ofthe clavicle. This muscle is concealed by the costo-coracoid membrane, an extension of the deep cervical fascia, by w7hich it is invested. Relations.—By its upper surface with the clavicle. By the lower with the subclavian artery and vein and brachial plexus, which separate it from the first rib. In front with the pectoralis major, the costo-coracoid mem- brane being interposed. Actions.—The pectoralis major draws the arm against the thorax, while its upper fibres assist the upper part of the trapezius in raising the shoulder as in supporting weights. The lower fibres depress the shoulder with the aid of the latissimus dorsi. Taking its fixed point from the shoulder, the pectoralis major assists the pectoralis minor, subclavius, and serratus magnus, in drawing up and expanding the chest. The pectoralis minor, in addition to this action, draws upon the coracoid process, and assists in rotating the scapula upon the chest. The subclavius draws the clavicle downwards and forwards, and thereby assists in steadying the shoulder. All the muscles of this group are agents in forced respiration, but are in- capable of acting until the shoulders are fixed. Lateral Thoracic Region. Serratus magnus. The Serratus Magnus (serratus, indented like the edge of a saw), arises by fleshy serrations from the nine upper ribs excepting the first, and extends backwards upon the side of the chest, to be inserted into the whole length of the base of the scapula upon its anterior, aspect. In structure the muscle is composed of three portions, a superior portion formed by two serrations attached to the second rib, and inserted into the inner sur- face of the superior angle of the scapula, a middle portion composed of the serrations connected with the third and fourth ribs, and inserted into the greater part of the posterior border, and an inferior portion consisting of the last five serrations which indigitate with the obliquus externus and form a thick muscular fasciculus which is inserted into the scapula near its inferior angle. Relations.—By its superficial surface with the pectoralis major and mi- nor, the subscapularis, and the axillary vessels and nerves. By its deep surface with the ribs and intercostal muscles, to which it is connected by an extremely loose cellular tissue. Actions.—The serratus magnus is the great external inspiratory muscle, raising the ribs when the shoulders are fixed, and thereby increasing the cavity of the chest. Acting upon the scapula, it draws the shoulder for- wards, as we see to be the case in diseased lungs, where the chest has become almost fixed from apprehension of the expanding action of the respiratory muscles. Anterior Scapular Region. Subscapularis. The Subscapularis muscle arises from the whole of the under surface of the scapula excepting the superior and inferior angle, and terminates by POSTERIOR SCAPULAR REGION. 227 a broad and thick tendon, which is inserted into the lesser tuberosity of the humerus. The substance of the muscle is traversed by several intersecting membranous layers from which muscular fibres arise, the intersections being attached to the ridges on the surface of the scapula. Its tendon forms part of the capsule of the joint, glides over a large bursa which separates it from the base of the coracoid process, and is lined by a pro- longation of the synovial membrane of the articulation. Relations.—By its anterior surface with the serratus magnus, coraco- brachialis, and axillary vessels and nerves. By its posterior surface with the scapula, the subscapular vessels and nerves, and the shoulder joint. Action.—It rotates the head of the humerus inwards, and is a powerful defence to the joint. When the arm is raised, it draws the humerus downwards. Posterior Scapular Region. Supra-spinatus, Teres minor, Infra-spinatus, Teres major. The Supra-spinatus muscle (supra, above; spina, the spine) arises from the whole of the supra-spinous fossa, and is inserted into the upper- most depression on the great tuberosity of the humerus. The tendon of this muscle cannot be well seen until the acromion process is removed. Relations.—By its upper surface, with the trapezius, the clavicle, acro- mion, and coraco-acromion ligament. From the trapezius it is separated by a strong fascia. By its lower surface, with the supra-spinous fossa, the supra-scapular vessels and nerve, and the upper part of the shoulder joint, forming part of the capsular ligament. The Infra-spinatus (infra, beneath; spina, the spine) is covered in by a layer of tendinous fascia, which must be removed before the fibres ofthe muscle can be seen, the deltoid muscle having been previously turned down from its scapular origin. It arises from the whole of the infra-spinous fossa, and from the fascia above-mentioned, and is inserted into the middle depression upon the greater tuberosity of the humerus. Relations.—By its posterior surface, with the deltoid, latissimus dorsi and integument. By its anterior surface, with the infra-spinous fossa, su- perior and dorsal scapular vessels, and shoulder joint; its tendon being lined by a prolongation from the synovial membrane. By its upper border, it is in relation with the spine of the scapula, and by the lower, with the teres minor, with which it is closely united. The Teres Minor muscle (teres, round) arises from the middle third of the inferior border of the scapula, and is inserted into the low7er depres- sion on the great tuberosity of the humerus. The tendons of these three muscles, with that of the subscapularis, are in immediate contact with the shoulder joint, and form part of its ligamentous capsule, thereby preserving the solidity of the articulation. They are therefore the structures most frequently ruptured in dislocation of the head of the humerus. Relations. — By its posterior surface, with the deltoid, latissimus dorsi and inteo-ument. By its anterior surface, with the inferior border, and part of the dorsum of the scapula, the dorsalis scapulae vessels, scapular head of the triceps, and shoulder joint. By its upper border, with the infra-spinatus; and by the lower, with the latissimus dorsi, teres major, and long head of the triceps. 228 ACROMIAL REGION. The Teres Major muscle arises from the lower third of the inferior border of the scapula, encroaching a little upon its dorsal aspect, and is inserted into the posterior bicipital ridge. Its tendon lies immediately behind that of the latissimus dorsi, from which it is separated by a syno- vial membrane. Relations. — By its posterior surface, with the latissimus dorsi, scapular head of the triceps and integument. By its anterior surface, with the subscapularis, latissimus dorsi, coraco-brachialis, short head of the biceps, axillary vessels, and branches ofthe brachial plexus. By its upper border, it is in relation with the teres minor, from which it is separated by the scapular head of the triceps; and by the lower, it forms with the latissimus dorsi, the lower and posterior border of the axilla. A large triangular space exists between the two teres muscles, wrhich is divided into two minor spaces by the long head of the triceps. Actions. — The supra-spinatus raises the arm from the side; but only feebly, from the disadvantageous direction of the force. The infra-spinatus and teres minor are rotators of the head of the humerus outwards. The most important use of these three muscles is the protection of the joint, and defence against displacement of the head of the humerus, in which action they co-operate with the subscapularis. The teres major combines, with the latissimus dorsi, in rotating the arm inwards, and at the same time carrying it towards the side, and somewhat backwards. Acromial Region. Deltoid. The convexity of the shoulder is formed by a large triangular muscle, the deltoid (a, delta; sfSos, resemblance), which arises from the outer third of the clavicle, from the acromion process, and from the whole length of the spine of the scapula. The fibres from this broad origin converge to the middle of the outer side of the humerus, where they are inserted into a rough triangular elevation. This muscle is remarkable for its coarse texture, and for its numerous tendinous intersections, from which mus- cular fibres arise. The deltoid muscle may now be cut away from its origin, and turned down, for the purpose of bringing into view the muscles and tendons placed immediately around the shoulder joint. In so doing, a large bursa will be seen between the under surface of the muscle and the head of the humerus. Relations. — By its superficial surface, with a thin aponeurotic fascia, a few fibres of the platysma myoides, the superficial fascia and integument. By its deep surface, with the shoulder joint, from which it is separated by a thin tendinous fascia, and by a synovial bursa; with the coraco-acromial ligament, coracoid process, pectoralis minor, coraco-brachialis, both heads ofthe biceps, tendon ofthe pectoralis major, tendon ofthe supra-spinatus, infra-spinatus, teres minor, teres major, scapular and external head of the triceps, the circumflex vessels anterior and posterior, and humerus. By its anterior border, with the external border of the pectoralis major, from which it is separated by a cellular interspace, lodging the cephalic vein and descending branch of the thoracico-acromialis artery. Its posterior border is thin and tendinous above, where it is connected with the apo- neurotic covering of the infra-spinatus muscle, and thick below7. Actions. — The deltoid is the elevator muscle of the arm in a direct ANTERIOR HUMERAL REGION. 220 line, and by means of its extensive origin can carry the arm forwards or backwards, so as to range with the hand a considerable segment of a large circle. The arm, raised by the deltoid, is a good illustration of a lever of the third power, so common in the animal machine, by which velocity is gained at the expense of power. In this lever, the weight (hand) is at one extremity, the fulcrum (the glenoid cavity) at the opposite end, and the power (the in- sertion of the muscle) between the two, but nearer to the fulcrum than to the weight. Anterior Humeral Region. Coraco-brachialis, Biceps, Brachialis anticus. Dissection. — These muscles are exposed, on the removal of the integument and fascia from the ante- rior half of the upper arm, and the clearing away of the cellular tissue. The Coraco-Brachialis, a name composed of its points of origin and insertion, arises from the cora- coid process in common with the short head of the biceps; and is inserted into a rough line on the inner side of the middle of the humerus. Relations. — By its anterior surface with the deltoid, and pectoralis major. By its posterior surface, with the shoulder joint, the humerus, subscapularis, teres major, latissimus dorsi, short head of the triceps, and anterior circumflex vessels. By its internal border with the axillary and brachial vessels and, nerves, particularly with the median and external cutaneous nerve, by the latter of which it is pierced. By the external border with the short head of the biceps and brachialis anticus. The Biceps (bis—xs cross the back of the hand. Relations.—By its superficial surface, with the fascia of the fore-arm and back of the hand, and with the posterior annular ligament. By its deep surface, with the supinator brevis, extensor ossis metacarpi pollicis, extensor primi internodii, extensor secundi internodii, extensor indicis, posterior interosseous artery and nerve, wrist joint, metacarpal bones and interossei muscles, and phalanges. By its radial border, with the extensor carpi radialis longior and brevior. By the ulnar border, with the extensor minimi digiti, and extensor carpi ulnaris. The Extensor Minimi Digiti (auricularis) is an offset from the extensor communis, with which it is connected by means of a tendinous slip. Passing down to the inferior extremity of the ulna, it traverses a distinct fibrous sheath, and at the metacarpo-phalangeal articulation unites with the tendon derived from the common extensor. The common tendon then spreads out into a broad expansion, which divides into three slips, to be inserted, as in the other fingers, into the last tw7o phalanges. It is to this muscle that the little finger owes its power of separate extension; and from being called into action when the point of the finger is intro- duced into the meatus of the ear, for the purpose of removing unpleasant sensations or producing titillation, the muscle wras called by the old writers "auricularis." The Extensor Carpi Ulnaris arises from the external condyle and from the upper tw7o-thirds of the border of the ulna. Its tendon passes through the posterior groove, in the lower extremity of the ulna, to be inserted into the base of the metacarpal bone of the little finger. Relations. — By its superficial surface, with the fascia of the fore-arm, and posterior annular ligament. By its deep surface, with the supinator brevis, extensor ossis metacarpi pollicis, extensor secundi internodii, ex- tensor indicis, ulna, and wrist joint. By its radial border, it is in relation with the extensor communis digitorum, and extensor minimi digiti: and by the ulnar border, with the anconeus. The Anconeus is a small triangular muscle, having the appearance of being a continuation of the triceps; it arises from the outer condyle, and is inserted into the olecranon and triangular surface on the upper extremity of the ulna. Relations. — By its superficial surface with a strong tendinous aponeu- rosis derived from the triceps. By its deep surface with the elbow7 joint, orbicular ligament, and slightly with the supinator brevis. Deep Layer. Supinator brevis, Extensor ossis metacarpi pollicis, Extensor primi internodii pollicis, Extensor secundi internodii pollicis, Extensor indicis. EXTENSOR PRIMI INTERNODII POLLICIS. 237 Fig 125.« Dissection.—The muscles of the superficial layer should be removed in order to bring the deep group completely into view. The Supinator Brevis cannot be seen in its en- tire extent until the radial extensors of the carpus are divided from their origin. It arises from the external condyle, from the external lateral and or- bicular ligament, and from the ulna, and winds around the upper part of the radius, to be inserted into the upper third of its oblique line. The pos- terior interosseous artery and nerve are seen perfo- rating the lower border of this muscle. Relations.—By its superficial surface with the pronator radii teres, supinator longus, extensor carpi radialis longior and brevior, extensor com- munis digitorum, extensor carpi ulnaris, anconeus, the radial artery and veins, the musculo-spiral nerve, radial and posterior interosseous nerve. By its deep surface with the elbow-joint and its ligaments, the interosseous membrane, and the radius. The Extensor Ossis Metacarpi Pollicis is flaced immediately below the supinator brevis. t arises from the ulna, interosseous membrane, and radius, and is inserted, as its name implies, into the base of the metacarpal bone of the thumb. Its tendon passes through the groove immediately in front ofthe styloid process ofthe radius. Relations.—By its superficial surface with the extensor carpi ulnaris, extensor minimi digiti, extensor communis digitorum, fascia of the fore- arm, and annular ligament. By its deep surface with the ulna, interosse- ous membrane, radius, tendons of the extensor carpi radialis longior and brevior, and supinator longus, and at the wrist with the radial artery. By its upper border with the edge of the supinator brevis. By its lower border with the extensor secundi and primi internodii. The muscle is crossed by branches ofthe posterior interosseous artery and nerve. The Extensor Primi Internodii Pollicis, the smallest of the muscles in this layer, arises from the interosseous membrane and ulna, and passes through the same groove with the extensor ossis metacarpi, to be inserted into the base ofthe first phalanx ofthe thumb. Relations.—The same as those ofthe preceding muscle with the excep- tion of the extensor carpi ulnaris. The muscle accompanies the extensor ossis metacarpi. The Extensor Secundi Internodii Pollicis arises from the ulna, and interosseous membrane. Its tendon passes through a distinct canal in the annulai- ligament, and is inserted into the base of the last phalanx of the thumb. * The deep layer of muscles on the posterior aspect of the fore-arm. 1. The lower part of the humerus. 2. The olecranon. 3. The ulna. 4. The anconeus muscle. 5. The supinator brevis muscle. 6. The extensor ossis metacarpi pollicis. 7. The exten- sor primi internodii pollicis. S. The extensor secundi internodii pollicis. 9. The ex- tensor indicis. 10. The first dorsal interosseous muscle. The other three dorsal inter- ossei are seen between the metacarpal bones of their respective fingers. 238 MUSCLES OF THE HAND. Relations.—By its external surface with the same relations as the exten- sor ossis metacarpi. By its deep surf ace with the ulna, interosseous mem- brane, radius, wrist joint, radial artery, and metacarpal bone of the thumb The muscle is placed between the extensor primi internodii and extensor indicis. The Extensor Indicis arises from the ulna, as high up as the extensor ossis metacarpi pollicis, and from the interosseous membrane. Its tendon passes through a distinct groove in the radius, and is inserted into the aponeurosis formed by the common extensor tendon of the index finger. Relations.—The same as those of the preceding muscle, with the ex- ception of the hand, where the tendon rests upon the metacarpal bone of the fore finger and second interosseous muscle, and has no relation with the radial artery. The tendons of the extensors, as of the flexor muscles of the fore-arm, are provided with synovial bursae as they pass beneath the annular liga- ments : those of the back of the wrist have distinct sheaths, formed by the posterior annular ligament. Actions.—The anconeus is associated in its action with the triceps ex- tensor cubiti: it assists in extending the fore-arm upon the arm. The supinator longus and brevis effect the supination of the fore-arm, and an- tagonize the two pronators. The extensor carpi radialis longior and bre- vior, and ulnaris, extend the wrist in opposition to the two flexors of the carpus. The extensor communis digitorum restores the fingers to the straight position, after being flexed by the two flexors, sublimis and pro- fundus. The extensor ossis metacarpi, primi internodii, and secundi in- ternodii pollicis, are the especial extensors of the thumb, and serve to balance the actions of the flexor ossis metacarpi, flexor brevis, and flexor longus pollicis. The extensor indicis gives the character of extension to the index finger, and is hence named " indicator," and the extensor minimi digiti supplies that finger with the power of exercising a distinct extension. muscles of the hand. Radial or Thenar Region. Abductor pollicis, Flexor brevis pollicis, Flexor ossis metacarpi (opponens), Adductor pollicis. Dissection.—The hand is best dissected by making an incision along the middle of the palm, from the wrist to the base of the fingers, and crossing it at each extremity by a transverse incision, then turning aside the flaps of integument. For exposing the muscles of the radial region, the removal of the integument and fascia on the radial side will be suffi- cient. The Abductor Pollicis is a small, thin muscle, which arises from the scaphoid bone and annular ligament. It is inserted into the base of the first phalanx ofthe thumb. Relations.—By its superficial surface, with the external portion of the palmar fascia. By its deep surface, with the flexor ossis metacarpi. On its inner side it is separated by a narrow cellular interspace from the flexor brevis pollicis. This muscle must be divided from its origin and turned upwards, in order to see the next. MUSCLES OF THE HAND. 239 Fig. 126.* The Flexor Ossis Metacarpi (oppo- nens pollicis) arises from the trapezium and annular ligament, and is inserted into the whole length of the metacarpal bone. Relations.—By its superficial surface, with the abductor pollicis. By its deep surface, with the trapezio-metacarpal ar- ticulation, and with the metacarpal bone. Internally, with the flexor brevis pollicis. The flexor ossis metacarpi may now be divided from its origin and turned aside, in order to show the next muscle. The Flexor Brevis Pollicis consists of two portions, between which lies the tendon ofthe flexor longus pollicis. The external portion arises from the trapezium and annular ligament; the internal por- tion, from the trapezoides and os mag- num. They are both inserted into the base of the first phalanx of the thumb, having a sesamoid bone in each of their tendons, to protect the joint. Relations.—By its superficial surface, with the external portion of the palmar fascia. By its deep surface, with the adductor pollicis, tendon of the flexor carpi radialis, and trapezio-metacarpal articulation. By its ex- ternal surface, with the flexor ossis metacarpi and metacarpal bone. By its inner surface, with the tendons of the long flexor muscles and first lumbricalis. The Adductor Pollicis is a triangular muscle; it arises from the whole length of the metacarpal bone ofthe middle finger; and the fibres converge to its insertion into the base of the first phalanx. Relations.—By its anterior surface with the flexor brevis pollicis, ten- dons of the deep flexor of the fingers, lumbricales, and deep palmar arch. By its posterior surface with the metacarpal bones of the index and middle fingers, the interossei of the second interosseous space, and the abductor indicis. Its inferior border is subcutaneous. Ulnar, or Hypothenar Region. Palmaris brevis, Abductor minimi digiti, Flexor brevis minimi digiti, Flexor ossis metacarpi (adductor). *The muscles ofthe hand. 1. The annular ligament. 2, 2. The origin and insertion ofthe abductor pollicis muscle; the middle portion has been removed. 3. The flexor ossis metacarpi, or opponens pollicis. 4. One portion of the flexor brevis pollicis. 5. The deep portion of the flexor brevis pollicis. 6. The adductor pollicis. 7, 7. The lunibricales muscles, arising from the deep flexor tendons, upon which the numbers are placed. The tendons of the flexor sublimis have been removed from the palm of tne hand. 8. One ofthe tendons of the deep flexor, passing between the two terminal slips of the tendon of the flexor sublimis, to reach the last phalanx. 9. The tendon of the flexor longus pollicis, passing between the two portions of the flexor brevis to the last phalanx. 10. The abductor minimi digiti. 11. The flexor brevis minimi digiti. The edge of the flexor ossis metacarpi, or adductor minimi digiti, is seen projecting beyond the inner border of the flexor brevis. 12. The prominence of the pisiform bone. 13. The first dorsal interosseous muscle. 240 MUSCLES OF THE HAND. Dissection.—Turn aside the ulnar flap of integument in the palm of the hand : in doing this, a subcutaneous muscle, the palmaris brevis will be exposed. After examining this muscle remove it with the deep fascia, in order to bring into view the muscles ofthe little finger. The Palmaris Brevis is a thin plane of muscular fibres which arises from the annular ligament and palmar fascia, and passes transversely in- wards, to be inserted into the integument on the inner border ofthe hand. Relations.—-By its superficial surface with the fat and integument of the ball of the little finger. By its deep surface with the internal portion of the palmar fascia, which separates it from the ulnar artery veins, and nerve and from the muscles ofthe inner border ofthe hand. The Abductor Minimi Digiti is a small tapering muscle which arises from the pisiform bone, and is inserted into the base of the first phalanx of the little finger. Relations.—By its superficial surface with the internal portion of the deep fascia and the palmaris brevis: by its deep surface with the flexor ossis metacarpi and metacarpal bone. By its inner border with the flexor brevis minimi digiti. The Flexor Brevis Minimi Digiti is a small muscle arising from the unciform bone and annular ligament, and inserted into the base of the first phalanx. It is sometimes wanting. Relations.—By its superficial surface with the internal portion of the palmar fascia, and the palmaris brevis. By its deep surface with the flexor ossis metacarpi, and metacarpal bone. Externally with the abductor minimi digiti, from which it is separated near its origin by the deep palmar branch of the ulnar nerve and communicating artery. Internally with the tendons of the flexor sublimis and profundus. The Flexor Ossis Metacarpi (adductor, opponens) arises from the unciform bone and annular ligament, and is inserted into the whole length of the metacarpal bone of the little finger. Relations.—By its superficial surface with the flexor brevis and abductor minimi digiti. By its deep surface with the interossei muscles of the last metacarpal space, the metacarpal bone, and the flexor tendons of the little finger. Palmar Region. Lumbricales, Interossei palmares, Interossei dorsales. The Lumbricales, four in number, are accessories to the deep flexor muscle. They arise from the tendons of the deep flexor ; the first and second from the palmar side, the third from the ulnar, and the fourth from the radial side; and are inserted into the aponeurotic expansion of the extensor tendons on the radial side of the fingers. The third, or that of the tendon of the ring finger, sometimes bifurcates, otherwise it is inserted wholly into the extensor tendon of the middle finger. Relations.—In the palm of the hand with the flexor tendons ; at their insertion, with the tendons of the interossei and the metacarpo-phalangeal articulations. The Palmar Interossei, three in number, are placed upon the meta- carpal bones, rather than between them. They arise from the base of the metacarpal bone of one finger, and are inserted into the base of the first MUSCLES OF THE HAND. Fig. 127.» Fig. 128,-j- 241 phalanx and aponeurotic expansion of tne extensor tendon of the same ringer. The first belongs to the index finger; the second to the ring finger; and the third to the little finger; the middle finger being ex- cluded. Relations.—By their palmar surface with the flexor tendons and with the deep muscles in the palm of the hand. By their dorsal surface with the dorsal interossei. On one side with the metacarpal bone, on the other with the corresponding dorsal interosseous. Dorsal Interossei.—On turning to the dorsum of the hand, the four dorsal interossei are seen in the four spaces between the metacarpal bones. They are bipenniform muscles and arise by'two heads, from the adjoining sides of the base of the metacarpal bones. They are inserted into the base ofthe first phalanges, and aponeurosis ofthe extensor tendons. The first is inserted into the index finger, and from its use is called abductor indicis,t. the second and third are inserted into the middle finger compensating its exclusion from the palmar group ; the fourth is attached to the ring finger; so that each finger is provided with two interossei, with the exception of the little finger, as may be shown by means of a table, thus:— one dorsal (abductor indicis), one palmar. Middle finger, two dorsal. r,. j. { one palmar, Rtngfinger, j Qne Jj^ Little finger, remaining palmar. Relations.—By their dorsal surface with a thin aponeurosis which sepa- rates them from the tendons on the dorsum of the hand. By their palmar Index finger, 1. Adductor indicis. 2. Abductor annularis. 3. Interosseous 1. Abductor indicis. 2. Abductor medii. 3. Adductor medii. * Palmar interossei. auricularis. ■j- Dorsal interossei. 4. Adductor annularis. .... t Horner divides this muscle and calls one portion of it abductor indicis and the other prior indicis. Wilson's description is the best, as it makes the analogy between the foot and hand complete, whilst there is a great discrepancy in Horner's mode of describing them.—G. 21 Q 242 MUSCLES OF THE LOWER EXTREMITY. surface with the muscles and tendons in the palm of the hand. By one side with the metacarpal bone ; by the other with the corresponding palmar interosseous. The abductor indicis is in relation by its palmar surface with the adductor pollicis, the arteria magna pollicis being interposed. The radial artery passes into the palm of the hand between the two heads of the first dorsal interosseous muscle and the perforating branches of the deep palmar arch, between the heads of the other dorsal interossei. Actions.—The actions of the muscles of the hand are expressed in their names. Those of the radial region belong to the thumb, and provide for three of its movements, abduction, adduction, and flexion. The ulnar group, in like manner, are subservient to the same motions of the little finger, and the interossei are abductors and adductors of the several fin- gers. The lumbricales are accessory in their actions to the deep flexors: they were called by the earlier anatomists, fidicinii, i. e. fiddlers' muscles, from an idea that they might effect the fractional movements by which the performer is enabled to produce the various notes on that instrument. In relation to the axis of the hand, the four dorsal interossei are abduc- tors, and the three palmar, adductors. It will therefore be seen that each finger is provided with its proper adductor and abductor, two flexors, and (with the exception of the middle and ring fingers) two extensors. The thumb has moreover a flexor and extensor of the metacarpal bone; and the little finger a flexor of the metacarpal bone without an extensor. MUSCLES OF THE LOWER EXTREMITY. The muscles of the lower extremity may be arranged into groups cor- responding with the regions of the hip, thigh, leg, and foot, as in the fol- lowing table:— HIP. Gluteal Region. Gluteus medius, Pyriformis, Obturator internus, Obturator externus. Gluteus maximus, Gluteus minimus, Gemellus superior, Gemellus inferior, Quadratus femoris. THIGH. Anterior Femoral Region. Internal Femoral Region. Tensor vaginae femoris, Iliacus internus, Sartorius, Rectus, Vastus internus, Vastus externus. Crureus. Psoas magnus, Pectineus, Adductor longus. Adductor brevis, Adductor magnus, Gracilis. Posterior Femoral Region. Biceps, Semitendinosus, Semimembranosus. MUSCLES OF THE LOWER EXTREMITY, ETC. 243 Anterior Tibial Region. Tibialis anticus, Extensor longus digitorum, Peroneus tertius, Extensor longus pollicis. Fibular Region. Peroneus longus, Peroneus brevis. LEG. Posterior Tibial Region. Superficial Group. Gastrocnemius, Plantaris, Soleus. Deep [posterior'] Layer. Popliteus, Flexor longus pollicis, Flexor longus digitorum, Tibialis posticus. FOOT. Dorsal Region. Extensor brevis digitorum, Interossei dorsales. 1st Layer. Abductor pollicis, Abductor minimi digiti, Flexor brevis digitorum. 2d Layer. Musculus accessorius, Lumbricales. Plantar Region. 3d Layer. Flexor brevis pollicis, Adductor pollicis, Flexor brevis minimi dip-iti, Transversus pedis. 4th Layer. Interossei plantares. GLUTEAL REGION, Obturator internus, Gemellus inferior, Obturator externus, Quadratus femoris. Gluteus maximus, Gluteus medius, Gluteus minimus, Pyriformis, Gemellus superior, Dissection. — The subject being turned on its face, and a block placed beneath the os pubis to support the pelvis, the student commences the dissection of this region, by carrying an incision from the apex of the coccyx along the crest of the ilium to its anterior superior spinous process ; or vice versa, if he be on the left side. He then makes an incision from the posterior fifth of the crest of the ilium, to the apex of the trochanter major, this marks the upper border of the gluteus maximus; and a third incision from the apex of the coccyx along the fleshy margin of the lower border of the gluteus maximus, to the outer side of the thigh, about four inches below the apex ofthe trochanter major. He then reflects the inte- gument, superficial fascia, and deep fascia, which latter is very thin over this muscle, from the gluteus maximus, following rigidly the course of its fibres; and having exposed the muscle in its entire extent, he dissects the integument and superficial fascia from off the deep fascia which binds down the gluteus medius, the other portion of this region. 244 MUSCLES OF THE GLUTEAL REGION. Fig. 129* The Gluteus Maximus (y\ovrk, nates) is the thick, fleshy mass of muscle, of a quadrangular shape, which forms the con- vexity of the nates. In structure, it is ex- tremely coarse, being made up of large fibres, which are collected into fasciculi, and these again into distinct muscular masses, separated by deep cellular fur- row7s. It arises from the posterior fifth of the crest of the ilium, from the posterior surface of the sacrum and coccyx, and from the great sacro-ischiatic ligament. It passes obliquely outwTards and downwards, to be inserted into the rough line leading from the trochanter major to the linea aspera, and is continuous by means of its tendon with the fascia lata covering the outer side ofv the thigh. A large bursa is situated between the broad tendon of this muscle and the femur. Relations. — By its superficial surface with a thin aponeurotic fascia, which separates it from the superficial fascia and integument, and with the vastus externus, a bursa being interposed. By its deep surface with the gluteus medius, pyriformis, gemelli, obturator internus, quadratus femoris, sacro-ischiatic foramina, great sacro-ischiatic ligament, tuberosity of the ischium, semimembranosus, semitendinosus, biceps, and adductor magnus; the gluteal vessels and nerves, ischiatic vessels and nerves, and internal pudic vessels and nerve. By its upper border it overlaps the gluteus medius; and by the lower border forms the lower margin of the nates. The gluteus maximus must be turned down from its origin, in order to bring the next muscle into view. The Gluteus Medius is placed in front of, rather than beneath the gluteus maximus; and is covered in by a process of the deep fascia, which is very thick and dense. It arises from the outer lip of the crest of the ilium for four-fifths of its length, from the surface of bone between that border and the superior curved line on the dorsum ilii, and from the dense fascia above-mentioned. Its fibres converge to the outer part of the trochanter major, into which its tendon is inserted. Relations. — By its superficial surface with the tensor vaginae femoris, gluteus maximus, and its fascia. By its deep surface with the gluteus minimus, and gluteal vessels and nerves. By its lower border with the pyriformis muscle. A bursa is interposed between its tendon and the upper part of the trochanter major. * The deep muscles ofthe gluteal region. 1. The external surface ofthe ilium. 2. The posterior surface of the sacrum. 3. The posterior sacro-iliac ligaments. 4. The tuberosity of the ischium. 5. The great or posterior sacro-ischiatic ligament. 6. The lesser or anterior sacro-ischiatic ligament. 7. The trochanter major. 8. The gluteus minimus. 9. The pyriformis. 10. The gemellus superior. 11. The obturator internus muscle, passing out of the lesser sacro-ischiatic foramen. 12. The gemellus inferior. 13. The quadratus femoris. 14. The upper part of the adductor magnus 15 The vastus externus. 16. The biceps. 17. The gracilis. 18. The semitendinosus OBTURATOR INTERNUS. 245 This muscle should now be removed from its origin and turned down, so as to expose the next, which is situated beneath it. The Gluteus Minimus is a radiated muscle, arising from the surface of the dorsum ilii, between the superior and inferior curved lines; its fibres converge to the anterior border of the trochanter major, into which it is inserted by means of a rounded tendon. There is no distinct line of separation between the gluteus medius and minimus anteriorly. Relations. — By its superficial surface with the gluteus medius, and gluteal vessels. By its deep surface with the surface of the ilium, the long tendon of the rectus femoris, and the capsule of the hip joint. A bursa is interposed between the tendon of the muscle and the trochanter. The Pyriformis muscle (pyrum, a pear, i. e. pear-shaped) arises from the anterior surface of the sacrum, by little slips that are interposed be- tween the first and fourth anterior sacral foramina, and from the adjoining surface of the ilium. It passes out of the pelvis, through ihe great sacro- ischiatic foramen, and is inserted by a rounded tendon into the trochanteric fossa of the femur. Relations. — By its superficial or external surface with the sacrum and gluteus maximus. By its deep or pelvic surface with the rectum, the sacral plexus of nerves, the branches of the internal iliac artery, the great sacro-ischiatic notch, and the capsule ofthe hip joint. By its upper border with the gluteus medius and gluteal vessels and nerves. By its lower border with the gemellus superior, ischiatic vessels and nerves, and internal pudic vessels and nerve. The Gemellus Superior (gemellus, double, twin) is a small slip of muscle, situated immediately below the pyriformis; it arises from the spine of the ischium, and is inserted into the upper border of the tendon of the obturator internus, and into the trochanteric fossa of the femur. The gemellus superior is not unfrequently wanting. Relations. — By its superficial surface with the gluteus maximus, the ischiatic vessels and nerves, and internal pudic vessels and nerve. By its deep surface with the pelvis, and capsule of the hip joint. The Obturator Internus arises from the inner surface of the anterior wall of the pelvis, being attached to the margin of bone around the obtu- rator foramen, and to the obturator membrane. It passes out of the pelvis through the lesser sacro-ischiatic foramen, and is inserted by a flattened tendon into the trochanteric fossa of the femur. The lesser sacro-ischiatic notch, over which this muscle plays as through a pulley, is faced with cartilage, and provided with a synovial bursa to facilitate its movements. The tendon of the obturator is supported on each side by the two gemelli muscles (hence their names), which are inserted into the sides of the ten- don, and appear to be auxiliaries or superadded portions of the obturator internus. Relations.—By its superficial or posterior surface with the internal pudic vessels and nerve, the obturator fascia, which separates it from the levator ani and viscera of the pelvis, the sacro-ischiatic ligaments, gluteus maxi- mus, and ischiatic vessels and nerves. By its deep or anterior surface with' the obturator membrane and the margin of bone surrounding it, the cartilaginous pulley ofthe lesser ischiatic foramen, the external surface of the pelvis, and the capsular ligament of the hip joint. By its upper border, within the pelvis, with the obturator vessels and nerve; externally to the 21* 246 ANTERIOR FEMORAL REGION. pelvis, with the gemellus superior. By its lower border with the gemellus inferior. The Gemellus Inferior arises from the posterior point of the tuberosity of the ischium, and is inserted into the lower border of the tendon of the obturator internus, and into the trochanteric fossa of the femur. Relations. — By its superficial surface with the gluteus maximus, and ischiatic vessels and nerves. By its deep surface with the external surface of the pelvis, and capsule 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. In this region the tendon only of the obturator externus can be seen, situated deeply between the gemellus inferior and the upper border of the quadratus femoris. To expose this muscle fully, it is necessary to dissect it from the anterior part of the thigh, after the removal of the pectineus, adductor longus and adductor brevis muscles. The Obturator Externus muscle (obturare, to stop up) arises from the obturator membrane, and from the surface of bone immediately sur- rounding it anteriorly, viz. from the ramus of the os pubis and ischium: its tendon passes behind the neck of the femur, to be inserted with the external rotator muscles, into the trochanteric fossa of the femur. Relations.—By its superficial or anterior surface with the tendon of the psoas and iliacus, pectineus, adductor brevis and magnus, the obturator vessels and nerve. By its deep or posterior surface with the obturator membrane and the margin of bone which surrounds it, the lower part of the capsule ofthe hip joint and the quadratus femoris. The Quadratus Femoris (square-shaped) arises from the external bor- der of the tuberosity of the ischium, and is inserted into a rough line on the posterior border ofthe trochanter major, which is thence named linea quadrati. Relations.—By its posterior surface with the gluteus maximus, and is- chiatic vessels and nerves. By its anterior surface with the tendon of the obturator externus, and trochanter minor, a synovial bursa often separating it from the latter. By its upper border with the gemellus inferior; and by the lower border with the adductor magnus. Actions.—The glutei muscles are abductors of the thigh, when they take their fixed point from the pelvis. Taking their fixed point from the thigh, they steady the pelvis on the head of the femur; this action is pe- culiarly obvious in standing on one leg; they assist also in carrying the leg forward, in progression. The gluteus minimus being attached to the anterior border of the trochanter major, rotates the limb slightly inwards. The gluteus medius and maximus, from their insertion into the posterior aspect of the bone, rotate the limb outwards; the latter is, moreover, a tensor of the fascia of the thigh. The other muscles rotate the limb out- wards, everting the knee and foot; hence they are named external rotators. Anterior Femoral Region. Tensor vaginae femoris, Vastus internus, Sartorius, Vastus externus, Rectus, Crureus. Dissection.—Make an incision along the line of Poupart's ligament, from the anterior superior spinous process of the ilium to the spine of the TENSOR VAGINA FEMORIS—SARTORIUS. 247 Fig. 130.* os pubis ; and a second, from the middle ofthe preceding down the inner side of the thigh, and across the inner condyle of the femur, to the head of the tibia, where it may be bounded by a transverse incision. Turn back the integument from the whole of this region, and examine the super- ficial fascia; which is next to be removed in the same manner. After the deep fascia has been well considered, it is likewise to be removed, by dis- secting it off in the course of the fibres of the muscles. As it might not be convenient to the junior student to expose so large a surface at once as ordered in this dissection, the vertical incision may be crossed by one or two transverse incisions, as may be deemed most proper. The Tensor Vagina Femoris (stretcher of the sheath of the thigh) is a short flat muscle, situated on the outer side ofthe hip. It arises from the crest of the ilium, near its anterior superior spinous process, and is inserted between two layers of the fascia lata at about one-fourth down the thigh. Relations.—By its superficial surface with the fascia lata and integument. By its deep surface with the in- ternal layer of the fascia lata, gluteus medius, rectus and vastus externus. By its inner border near its ori- gin with the sartorius. The Sartorius (tailor's muscle) is a long riband- like muscle, arising from the anterior superior spinous process of the ilium, and from the notch immediately below that process; it crosses obliquely the upper third of the thigh, descends behind the inner condyle of the femur, and is inserted by an aponeurotic expan- sion into the inner tuberosity of the tibia. This ex- pansion covers in the insertion of the tendons of the gracilis and semitendinosus muscles. The inner bor- der of the sartorius muscle is the guide to the opera- tion for tying the femoral artery in the middle of its course. Relations.—By its superficial surface with the fascia lata and some cutaneous nerves. By its deep surface with the psoas and iliacus, rectus, sheath of the femo- ral vessels and saphenous nerves, vastus internus, ad- ductor longus, adductor magnus, gracilis, long saphe- nous nerve, internal lateral ligament of the knee joint. By its expanded insertion with the tendons of the gra- cilis and semi-tendinosus, a synovial bursa being inter- posed. At the knee joint its posterior border is in relation with the internal saphenous vein. At the up- per third of the thigh the sartorius forms, with the lower border of the adductor longus, an isosceles triangle, whereof the base corresponds with Poupart's ligament. line drawn from the middle of the base of the apex of this triangle, imme- diately overlies the femoral artery with its sheath. * The muscles of the anterior femoral region. 1. The crest of the ilium. 2. Its an- terior superior spinous process. 3. The gluteus medius. 4. The tensor vaginae femoris; its insertion into the fascia lata is shown inferiorly. 5. The sartorius. 6. The rectus. 7. The vastus externus. S. The vastus internus. 9. The patella. 10. The iliacus in- ternus. 11. The psoas magnus. 12. The pectineus. 13. The adductor longus. 14. Part of the adductor magnus. 15. The gracilis. A perpendicular 248 VASTUS INTERNUS—CRUREUS. The Rectus (straight) muscle is fusiform in its shape and bipenniform in the disposition of its fibres. It arises by two round tendons, one from the anterior inferior spinous process ofthe ilium, the other from the upper lip ofthe acetabulum; and is inserted by a broad and strong tendon, into the upper border of the patella. It is more correct to consider the patella as a sesamoid bone, developed within the tendon of the rectus; and the ligamentum patellae as the continuation of the tendon to its insertion into the tubercle of the tibia. Relations.—By its superficial surface with the gluteus medius, psoas and iliacus, sartorius; and, for the lower three-fourths of its extent, with the fascia lata. By its deep surface with the capsule of the hip joint, the externa] circumflex vessels, crureus, and vastus internus and externus. The rectus must now be divided through its middle, and the two ends turned aside, to bring clearly into view7 the next muscles. The three next muscles are generally considered collectively under the name of triceps extensor cruris. Adopting this view, the muscle surrounds the whole of the femur, excepting the rough line (linea aspera) upon its posterior aspect. Its division into three parts is not well defined; the fleshy mass upon each side being distinguished by the names of vastus internus and externus, the middle portion by that of crureus. The Vastus Externus, narrow7 below7 and broad above, arises from the outer border of the patella, and is inserted into the femur and outer side of the linea aspera, as high as the base of the trochanter major. Relations.—By its superficial surface with the fascia lata, rectus, biceps, semi-membranosus and gluteus maximus, a synovial bursa being inter- posed between it and the latter. By its deep surface with the crureus and femur. The Vastus Internus, broad below and narrow above, arises from the inner border of the patella, and is inserted into the femur and inner side of the linea aspera as high up as the anterior intertrochanteric line. Relations.—By its superficial surface with the psoas and iliacus, rectus, sartorius, femoral artery and vein and saphenous nerves, pectineus, ad- ductor longus, brevis, and magnus, and fascia lata. By its deep surface with the crureus and femur. The Crureus (crus, the leg) arises from the upper border of the patella, and is inserted into the front aspect of the femur, as high as the anterior intertrochanteric line. When the crureus is divided from its insertion, a small muscular fasciculus is often seen upon the lower part of the femur, which is inserted into the pouch of synovial membrane, that extends up- wards from the knee joint, behind the patella. This is named, from its situation, sub-crureus, and would seem to be intended to support the synovial membrane. Relations. — By its superficial surface with the external circumflex vessels, the rectus, vastus internus and externus. By its deep surface with the femur, the sub-crureus, and synovial membrane of the knee joint. Actions. — The tensor vaginae femoris renders the fascia lata tense, and slightly inverts the limb. The sartorius flexes the leg upon the thigh, and, continuing to act, the thigh upon the pelvis, at the same time carrying the leg across that of the opposite side, into the position in which tailors sit; hence its name. Taking its fixed point from below7, it assists the extensor muscles in steadying the leg, for the support of the trunk. The other four muscles have been collectively named quadriceps extensor, from their INTERNAL FEMORAL REGION. 249 similarity of action. They extend the leg upon the thigh, and obtain a great increase of power by their attachment to the patella, which acts as a fulcrum. Taking their fixed point from the tibia, they steady the femur upon the leg, and the rectus, by being attached to the pelvis, serves to balance the trunk upon the lower extremity. Internal Femoral Region. Iliacus internus, Adductor brevis, Psoas magnus, Adductor magnus, Pectineus, Gracilis. Adductor longus, Dissection. — These muscles are exposed by the removal of the inner flap of integument recommended in the dissection of the anterior femoral region. The iliacus and psoas arising from within the abdomen, can only be seen in their entire extent after the removal of the viscera from that cavity. The Iliacus Internus is a flat radiated muscle. It arises from the whole extent of the inner concave surface ofthe ilium ; and, after joining with the tendon of the psoas, is inserted into the trochanter minor of the femur. A few fibres of this muscle are derived from the base of the sa- crum, and others from the capsular ligament ofthe hip joint. Relations.—By its anterior surface, within the pelvis, with the external cutaneous nerve, and with the iliac fascia, which separates the muscle from the peritoneum, on the right from the caecum, and on the left from the sigmoid flexure of the colon; externally to tj:ie pelvis with the fascia lata, rectus, and sartorius. By its posterior surface with the iliac fossa, margin of the pelvis, and with the capsule of the hip joint, a synovial bursa of large size being interposed, which is sometimes continuous with the synovial membrane of the articulation. By its inner border with the psoas magnus and crural nerve. The Psoas Magnus (4-o'a, lumbus, a loin), situated by the side of the vertebral column in the loins, is a long fusiform muscle. It arises from the intervertebral substances, part of the bodies and bases of the trans- verse processes, and from a series of tendinous arches, thrown across the constricted portion of the last dorsal and four upper lumbar vertebrae. These arches are intended to protect the lumbar arteries and sympathetic filaments of nerves from pressure, in their passage beneath the muscle. From this extensive origin, the muscle passes along the margin of the brim ofthe pelvis, and beneath Poupart's ligament, to its insertion. The tendon of the psoas magnus unites with that of the iliacus, and the con- joined tendon is inserted, into the posterior part of the trochanter minor, a bursa being interposed. Relations. — By its anterior surface, with the ligamentum arcuatum in- ternum of the diaphragm, the kidney, the psoas parvus, genito-crural nerve, sympathetic nerve, its proper fascia, the peritoneum and colon, and along its pelvic border with the common and external iliac artery and vein. By its posterior surface, with the lumbar vertebrae, the lumbar ar- teries, quadratus lumborum, from which it is separated by the anterior layer of the aponeurosis of the transversalis, and with the crural nerve, which, near Poupart's ligament, gets to its outer side. The lumbar plexus of nerves is situated in the substance of the posterior part of the muscle. 250 ADDUCTOR BREVIS. In the thigh, the muscle is in relation with the fascia lata in front; the border ofthe pelvis and hip joint, from which it is separated by the syno- vial membrane, common to it and the preceding muscle, behind ; with the crural nerve and iliacus, to the outer side; and with the femoral artery, by which it is slightly overlaid, to the inner side. The Pectineus is a flat and quadrangular muscle; it arises from the pectineal line (pecten, a crest) of the os pubis, and from the surface of bone in front of that bone. It is inserted into the line leading from the anterior intertrochanteric line to the linea aspera ofthe femur. Relations.—By its anterior surface, with the pubic portion of the fascia lata, which separates it from the femoral artery and vein and internal sa- phenous vein, and lower down with the profunda artery. By its posterior surface, with the capsule of the hip joint, and with the obturator externus and adductor brevis, the obturator vessels being interposed. By its external border, with the psoas, the femoral artery resting upon the line of-interval. By its internal border, with the outer edge of the adductor longus. Ob- turator hernia is situated directly behind this muscle, which forms one of its coverings. The Adductor Longus (adducere, to draw to), the most superficial of the three adductors, arises, by a round and thick tendon, from the front surface of the os pubis, immediately below the angle; and assuming a flattened and expanded form as it descends, is inserted into the middle third of the linea aspera. Relations.—By its anterior surface, with the pubic portion of the fascia lata, and near its insertion with the femoral artery and vein. By its pos- terior surface, with the adductor brevis and magnus, the anterior branches of the obturator vessels and nerves, and near its insertion with the pro- funda artery and vein. By its outer border, with the pectineus ; and by the inner border, With the gracilis. The pectineus must be divided near its origin and turned outwards, and the adductor longus through its middle, turning its ends to either side, to bring into view the adductor brevis. The Adductor Brevis, placed beneath the pectineus and adductor longus, is fleshy, and thicker than the adductor longus ; it arises from the body and ramus ofthe os pubis, and is inserted into the upper third ofthe linea aspera. Relations.—By its anterior surface, with the pectineus, adductor longus, and anterior branches ofthe obturator vessels and nerve. By its posterior surface, with the adductor magnus, and posterior branches of the obturator 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 magnus. The adductor brevis is pierced near its insertion by the middle perforating artery. The adductor brevis may now be divided from its origin and turned outwards, or its inner two-thirds may be cut away entirely, when the ad- ductor magnus muscle will be exposed in its entire extent. The Adductor Magnus is a broad triangular muscle, forming a septum of division between the muscles situated on the anterior and those on the posterior aspect of the thigh. It arises, by fleshy fibres, from the ramus ofthe pubes and ischium, and from the side ofthe tuber ischii; and radi- ating in its passage outwards, is inserted into the whole length of the linea aspera, and inner condyle of the femur. The adductor magnus is pierced POSTERIOR FEMORAL REGION. 251 by five openings: the three superior, for the three perforating arteries; and the fourth, for the termination of the profunda. The fifth is the large oval opening, in the tendinous portion of the muscle, that gives passage to the femoral vessels. Relations.—By its anterior surface, with the pectineus, adductor brevis, adductor longus, femoral artery and vein, profunda artery and vein, with their branches, and with the posterior branches of the obturator vessels and nerve. By its posterior surface, with the semi-tendinosus, semi-membra- nosus, biceps, and gluteus maximus. By its inner border, with the gra- cilis and sartorius. By its upper border, with the obturator externus and quadratus femoris. The Gracilis (slender) is situated along the inner border of the thigh. It arises by a broad, but very thin tendon, from the body of the os pubis, along the edge of the symphysis, and from the margin ofthe ramus ofthe pubes and ischium; and is inserted, by a rounded tendon, into the inner tuberosity of the tibia, beneath the expansion of the sartorius. Relations.—By its inner or superficial surface, with the fascia lata, and below, with the sartorius and internal saphenous nerve; the internal sa- phenous vein crosses it, lying superficially to the fascia lata. By its outer or deep surface, with the adductor longus, brevis, and magnus, and the internal lateral ligament ofthe knee joint, from which it is separated by a synovial bursa, common to the tendons of the gracilis and semi-tendinosus. Actions.—The iliacus, psoas, pectineus, and adductor longus muscles bend the thigh upon the pelvis, and, at the same time, from the obliquity of their insertion into the lesser trochanter and linea aspera, rotate the en- tire limb outwards; the pectineus and adductors adduct the thigh power- fully ; and from the manner of their insertion into the linea aspera, they assist in rotating the limb outwards. The gracilis is likewise an adductor of the thigh; but contributes also to the flexion of the leg, by its attach- ment to the inner tuberosity of the tibia. Posterior Femoral Region. Biceps, Semi-tendinosus, Semi-membranosus. Dissection.'—Remove the integument and fascia on the posterior part ofthe thigh by two flaps, as on the anterior region, and turn aside the glu- teus maximus from the upper part; the muscles may then be examined. The Biceps Femoris (bis, double, xstpaX^, head) arises by two heads, one by a common tendon with the semi-tendinosus; the other muscular and much shorter, from the lower two-thirds of the external border of the linea aspera. This muscle forms the outer hamstring, and is inserted by a strong tendon into the head of the fibula; a portion of the tendon is con- tinued downwards into the fascia of the leg, and another is attached to the outer tuberosity of the tibia. Relations.—By its superficial or posterior surface with the gluteus maxi- mus and fascia lata. By its deep or anterior surface with the semi-mem- branosus, adductor magnus, vastus externus, the great sciatic nerve, pop- liteal artery and vein, and near its insertion with the external head of the gastrocnemius, and plantaris. By its inner border with the semi-tendi- nosus, and in the popliteal space with the popliteal artery and vein. The Semi-tendinosus, remarkable for its long tendon, arises in common with the lone head of the biceps, from the tuberosity of the ischium ; the 252 SEMI-MEMBRANOSUS. Fig. 131/ two muscles being closely united for several inches below their origin. It is inserted into the inner tuberosity of the tibia. Relations.—By its superficial surface with the glu- teus maximus, fascia lata, and at its insertion with the synovial bursa which separates its tendon from the ex- pansion of the sartorius. By its deep surface with the semi-membranosus, adductor magnus, internal head of the gastrocnemius, and internal lateral ligament of the knee joint, the synovial bursa common to it and the tendon of the gracilis being interposed. By its inner border with the gracilis; and by its outer border with the biceps. These two muscles must be dissected from the tube- rosity of the ischium, to bring into view the origin of the next. The Semi-membranosus, remarkable for the tendi- nous expansion upon its anterior and posterior surface, arises from the tuberosity of the ischium, in front of the common origin of the two preceding muscles. It is inserted into the posterior part of the inner tuberosity of the tibia; at its insertion the tendon splits into three portions, one of which is inserted in a groove on the inner side of the head of the tibia, beneath the internal lateral ligament. The second is continuous with an aponeurotic expansion that binds down the popliteus muscle, the popliteal fascia; and the third turns up- wards and outwards to the external condyle of the femur, forming the middle portion of the posterior ligament of the knee joint (ligamentum posticum Winslowii). tendons of the last two muscles, viz. the semi-tendinosus and semi-membranosus, with those of the gracilis and sartorius, form the inner hamstring. Relations.—By its superficial surface with the gluteus maximus, biceps, semi-tendinosus, fascia lata, and at its insertion with the tendinous expan- sion of the sartorius. By its deep surface with the quadratus femoris, ad- ductor magnus, internal head of the gastrocnemius, the knee joint, from which it is separated by a synovial membrane, and the popliteal artery and vein. By its inner border with the gracilis. By its outer border with the great ischiatic nerve, and in the popliteal space with the popliteal artery and vein. If the semi-membranosus muscle be turned down from its origin, the student will bring into view the broad and radiated expanse of the adduc- tor magnus, upon which the three flexor muscles above described rest. Actions. — These three hamstring muscles are the direct flexors of the * The muscles of the posterior femoral and gluteal region. 1. The gluteus medius, 2. The gluteus maximus. 3. The vastus externus, covered in by fascia lata. 4. The long head of the biceps. 5. Its short head. 6. The semi-tendinosus. 7. The semi- membranosus. 8. The gracilis. 9. A part of the inner border of the adductor magnus. 10. The edge of the sartorius. 11. The popliteal space. 12. The gastrocnemius muscle; its two heads. The tendon of the biceps forms the outer hamstring; and the sartorius with the tendons of the gracilis, semi-tendinosus, and semi-membranosus, the inner hamstring. The ANTERIOR TIBIAL REGION. 253 leg upon the thigh ; and by taking their origin from below, they balance the pelvis on the lower extremities. The biceps, from the obliquity of its direction, everts the leg when partially flexed, and the semi-tendinosus turns the leg inwards when in the same state of flexion. Anterior Tibial Region. Fig. 132* Tibialis anticus, Extensor longus digitorum, Peroneus tertius, Extensor proprius pollicis. Dissection.—The dissection of the anterior tibial region is to be commenced by carrying an incision along the middle of the leg, midway between the tibia and the fibula, from the knee to the ankle, and bounding it inferiorly by a transverse incision extending from one malleolus to the other. And to expose the tendons on the dorsum of the foot, •> the longitudinal incision may be carried onwards to the outer side of the base of the great toe, and be terminated by another incision directed across the heads of the metatarsal bones. The Tibialis Anticus muscle (flexor tarsi tibialis) arises from the upper two-thirds of the tibia, from the interosseous membrane, and from the deep fascia; its tendon passes through a distinct sheath in the annular ligament, and is inserted into the inner side of the internal cuneiform bone, and base of the metatarsal bone of the great toe. Relations. — By its anterior surface with the deep fascia, from which many of its superior fibres arise, and with the anterior annular ligament. By its posterior surface with the interosseous membrane, tibia, ankle joint, and bones of the tarsus with their articulations. By its internal surface with the tibia. By the external surface with the extensor longus digitorum, extensor proprius pollicis, and the anterior tibial vessels and nerve. The Extensor Longus Digitorum arises from the head of the tibia, from the upper three-fourths of the fibula, from the interosseous mem- brane, and from the deep fascia. Below, it divides into four tendons, which pass beneath the annular ligament, to be inserted into the second and third phalanges of the four lesser toes. The mode of insertion of the extensor tendons, both in the hand and in the foot, is remarkable: each tendon spreads into a broad aponeurosis over the first phalanx; this aponeurosis divides into three slips; the middle one is inserted into the * The muscles of the anterior tibial region. 1. The extensor muscles inserted into the patella. 2. The subcutaneous surface of the tibia. 3. The tibialis anticus. 4. The extensor longus digitorum. 5. The extensor proprius pollicis. 6. The peroneus tertius. 7. The peroneus longus. 8. The peroneus brevis. 9, 9. The borders of the sr.Vus muscle. 10. A part of the inner belly of the gastrocnemius. 11. The extensor brevis digitorum • the tendon in front of this number is that of the peroneus tertius; and that behind it, the tendon ofthe peroneus brevis. 22 254 POSTERIOR TIBIAL REGION. base of the second phalanx, and the two lateral slips are continued on- wards, to be inserted into the base of the third. Relations. — By its anterior surface with the deep fascia of the leg and foot, and with the anterior annular ligament. By its posterior surface with the interosseous membrane, fibula, ankle joint, extensor brevis digitorum which separates its tendons from the tarsus, and with the metatarsus and phalanges. By its inner surface with the tibialis anticus, extensor pro- prius pollicis, and anterior tibial vessels. By its outer border with the peroneus longus and brevis. The Peroneus Tertius (flexor tarsi fibularis) arises from the lower fourth of the fibula, and is inserted into the base of the metatarsal bone of the little toe. Although apparently but a mere division or continuation of the extensor longus digitorum, this muscle may be looked upon as analogous to the flexor carpi ulnaris of the fore-arm. Sometimes it is alto- gether wanting. The Extensor Proprius Pollicis lies between the tibialis anticus and extensor longus digitorum. It arises from the lower two-thirds of the fibula and interosseous membrane. Its tendon passes through a distinct sheath in the annular ligament, and is inserted into the base of the last phalanx of the great toe. Relations.—By its anterior surface, with the deep fascia of the leg and foot, and with the anterior annular ligament. By its posterior surface, with the interosseous membrane, the fibula, the tibia, the ankle joint, the extensor brevis digitorum, and the bones and articulations of the great toe. It is crossed upon this aspect by the anterior tibial vessels and nerve. By its outer side, with the extensor longus digitorum, and in the foot with the dorsalis pedis artery and veins; the outer side of its tendon upon the dor- sum of the foot being the guide to those vessels. By its inner side, with the tibialis anticus, and with the anterior tibial vessels. Actions.—The tibialis anticus and peroneus tertius are direct flexors of the tarsus upon the leg; acting in conjunction with' the tibialis posticus, they direct the foot inwards, and with the peroneus longus and brevis, outwards. They assist also in preserving the flatness of Ihe foot during progression. The extensor longus digitorum and extensor proprius pollicis, are direct extensors of the phalanges; but, continuing their action, they assist the tibialis anticus and peroneus tertius in flexing the entire foot upon the leg. Taking their origin from below, they increase the stability ofthe ankle joint. Posterior Tibial Region. Superficial Group. Gastrocnemius, Plantaris, Soleus. Dissection.—Make an incision from the middle of the popliteal space, down the middle of the posterior part of the leg to the heel, bounding it inferiorly by a transverse incision, passing betw-een the two malleoli. Turn aside the flaps of integument, and remove the fasciae from the whole of this region ; the gastrocnemius muscle will then be exposed. The Gastrocnemius (ya^oxv^.ov, the bellied part of the leg) arises, by two heads, from die two condyles of the femur, the inner head being PLANTARIS—SOLEUS. 255 the longest. They unite to form the beautiful muscle so Fig. 133* characteristic of this region of the limb. It is inserted, by means of the tendo Achillis, into the lower part of the posterior tuberosity of the os calcis, a synovial bursa being placed between that tendon and the upper part of the tuberosity. The gastrocnemius must be removed from its origin, and turned down, in order to expose the next muscle. Relations.—By its superficial surface, with the deep fascia of the leg, which separates it from the external saphenous vein, and with the external saphenous nerve. By its deep surface, with the lateral portions of the pos- terior ligament of the knee joint, the popliteus, plantaris, and soleus. The internal head of the muscle rests against the posterior surface of the internal condyle of the femur; the external head against the outer side of the external condyle. In the latter, a sesamoid bone is sometimes found. The Plantaris (planta, the sole of the foot), an ex- tremely diminutive muscle, situated between the gastroc- nemius and soleus, arises from the outer condyle of the femur; and is inserted, by its long and delicately slender tendon, into the inner side of the posterior tuberosity of the os calcis, by the side of the tendo Achillis: having crossed obliquely between the two muscles. The Soleus (solea, a sole), is the broad muscle upon which the plantaris rests. It arises, from the head and upper third of the fibula, from the oblique line and middle third of the tibia. Its fibres converge to the tendo Achillis, by which it is inserted into the posterior tuberosity of the os calcis. Between the fibular and tibial origins of this muscle is a tendinous arch, beneath which the popliteal vessels and nerve pass into the leg. Relations.—By its superficial surface, with the gastrocnemius and plan- taris. By its deep surface, with the intermuscular fascia, which separates it from the flexor longus digitorum, tibialis posticus, flexor longus pollicis, from the posterior tibial vessels and nerve, and from the peroneal vessels. Actions.—The three muscles of the calf draw powerfully on the os cal- cis, and lift the heel; continuing their action, they raise the entire body. This action is attained by means of a lever of the second power, the ful- crum (the toes) being at one end, the weight (the body supported on the tibia) in the middle, and the pow7er (these muscles) at the other extremity. They are, therefore, the walking muscles, and perform all movements that require the support of the whole body from the ground, as dancing, leaping, &c. Taking their fixed point from below, they steady the leg upon the foot. * The superficial muscles of the posterior aspect of the leg. 1. The biceps muscle forming the outer hamstring. 2. The tendons forming the inner hamstring. 3. The popliteal space. 4. The gastrocnemius muscle. 5, 5. The soleus. 6. The tendo Achillis. 7. The posterior tuberosity of the os calcis. 8. The tendons of the peroneus longus and brevis muscles passing behind the outer ankle. 9. The tendons of the tibialis posticus and flexor longus digitorum. passing into the foot behind the inner ankle. 256 FLEXOR LONGUS DIGITORUM. Deep Layer. Popliteus, Flexor longus pollicis, Flexor longus digitorum, Tibialis posticus.' Dissection.—After the removal of the soleus, the deep layer will be found bound down by an intermuscular fascia which is to be dissected away; the muscles may then be examined. The Popliteus muscle (poples, the ham of the leg) forms the floor of the popliteal region at its lower part, and is bound tightly down by a stror fascia derived from the middle slip of the tendon of the semi-membranosus muscle. It arises by a rounded tendon from a deep groove on the outer Fig. 134.* side of the external condyle of the femur, beneath the ex- ternal lateral ligament; and spreading obliquely over the head of the tibia, is inserted into the surface of bone above its oblique line. This line is called, from being the limit of insertion of the popliteal muscle, the popliteal line. Relations.—By its superficial surface with a thick fascia which separates it from the two heads of the gastrocne- mius, the plantaris, and the popliteal vessels and nerve. By its deep surface with the synovial membrane ofthe knee joint and with the upper part ofthe tibia. The Flexor Longus Pollicis is the most superficial of the next three muscles. It arises from the lower two- thirds of the fibula, and passes through a groove in the astragalus and os calcis, which is converted by tendinous fibres into a distinct sheath lined by a synovial mem- brane, into the sole of the foot; it is inserted into the base of the last phalanx of the great toe. Relations.—By its superficial surface with the intermus- cular fascia, which separates it from the soleus and tendo Achillis. By its deep surface with the tibialis posticus, fibula, fibular vessels, interosseous membrane, and ankle joint. By its outer border with the peroneus longus and brevis. By its inner border with the flexor longus digitorum. In the foot, the tendon of the flexor longus pollicis is connected with that of the flexor longus digitorum by a short tendinous slip. The Flexor Longus Digitorum (perforans) arises from the surface of the tibia, immediately below the popliteal line. Its tendon passes through a sheath common to it and the tibialis posticus be- hind the inner malleolus; it then passes through a second sheath which is * The deep layer of muscles of the posterior tibial region. 1. The lower extremity of the femur. 2. The ligamentum posticum Winslowii. 3. The tendon of the semi- membranosus muscle dividing into its three slips. 4. The internal lateral ligament of the knee joint. 5. The external lateral ligament. 6. The popliteus muscle. 7. The flexor longus digitorum. 8. The tibialis posticus. 9. The flexor longus pollicis. 1". The peroneus longus muscle. 11. The peroneus brevis. 12. The tendo Achillis divided near its insertion into the os calcis. 13. The tendons of the tibialis posticus and flexor longus digitorum muscles, just as they are about to pass beneath the internal annular ligament of the ankle; the interval between the latter tendon and the tendon of the flexor longus pollicis is occupied by the posterior tibial vessels and nerve. FIBULAR REGION. 257 connected with a groove in the astragalus and os calcis, into the sole of the foot, where it divides into four tendons, which are inserted into the base of the last phalanx of the four lesser toes, perforating the tendons of the flexor brevis digitorum. Relations.—By its superficial surface with the intermuscular fascia, which separates it from the soleus, and with the posterior tibial vessels and nerve. By its deep surface with the tibia and tibialis posticus. In the sole of the foot its tendon is in relation with the abductor pollicis and flexor brevis digitorum, which lie superficially to it, and it crosses the tendon of the flexor longus pollicis. At the point of crossing it receives the tendi- nous slip of communication from the latter. The flexor longus pollicis must now be removed from its origin, and the flexor longus digitorum drawn aside, to bring into view the entire ex- tent of the tibialis posticus. The Tibialis Posticus (extensor tarsi tibialis) lies upon the interosseous membrane, between the two bones of the leg. It arises by two heads from the adjacent sides of the tibia and fibula their whole length, and from the interosseous membrane. Its tendon passes inwards beneath the tendon ofthe flexor longus digitorum, and runs in the same sheath; it then passes through a proper sheath over the deltoid ligament, and beneath the calca- neo-scaphoid articulation to be inserted into the tuberosity of the scaphoid and internal cuneiform bone. While in the common sheath behind the internal malleolus, the tendon of the tibialis posticus lies internally to that ofthe flexor longus digitorum, from which it is separated by a thin fibrous partition. A sesamoid bone is usually met with in the tendon close to its insertion. Relations.—By its superficial surface with the intermuscular septum, the flexor longus pollicis, flexor longus digitorum, posterior tibial vessels and nerve, peroneal vessels, and in the sole of the foot with the abductor pollicis. By its deep surface with the interosseous membrane, the fibula and tibia, the ankle joint, and the astragalus. The anterior tibial artery passes between the two heads of the muscled The student will observe that the two latter muscles change their rela- tive position to each other in their course. Thus, in the leg, the position of the three muscles from within outwards, is, flexor longus digitorum, tibialis posticus, flexor longus pollicis. At the inner malleolus, the rela- tion of the tendons is, tibialis posticus, flexor longus digitorum, both in the same sheath; then a broad groove, which lodges the posterior tibial artery, venae comites, and nerve; and lastly, the flexor longus pollicis. Actions.—The popliteus is a flexor of the tibia upon the thigh, carrying it at the same time inwards, so as to invert the leg. The flexor longus pollicis and flexor longus digitorum are the long flexors of the toes; their tendons are connected in the foot by a short tendinous band, hence they necessarily act together. The tibialis posticus is an extensor ofthe tarsus upon the leg, and an antagonist to the tibialis anticus. It combines with the tibialis anticus in adduction of the foot. Fibular Region. Peroneus longus, Peroneus brevis. 22* R 258 FOOT--DORSAL REGION. Dissection. — These muscles are exposed by continuing the dissection of the anterior tibial region outwards beyond the fibula, to the border of the posterior tibial region. The Peroneus Longus (vegivYi, fibula, extensor tarsi fibularis longior) muscle arises from the head and upper third of the outer side of the fibula, and terminates in a long tendon, which passes behind the external mal- leolus, and obliquely across the sole of the foot, through the groove in the cuboid bone, to be inserted into the base of the metatarsal bone of the great toe. Its tendon is thickened where it glides behind the external malleolus, and a sesamoid bone is developed in that part which plays upon the cuboid bone. Relations.—By its superficial surface with the fascia of the leg and foot. By its deep surface with the fibula, peroneus brevis, os calcis, and cuboid bone, and near the head ofthe fibula with the fibular nerve. By its ante- rior border it is separated from the extensor longus digitorum by the attachment of the fascia of the leg to the fibula; and by the posterior border by the same medium from the soleus and flexor longus pollicis. The peroneus longus is furnished with three tendinous sheaths and as many synovial membranes; the first is situated behind the external mal- leolus, and is common to this muscle and the peroneous brevis, the second on the outer side of the os calcis, and the third on the cuboid bone. The Peroneus Brevis (extensor tarsi fibularis brevior) lies beneath the peroneus longus; it arises from the lowrer half of the fibula, and terminates in a tendon which passes behind the external malleolus and through a groove in the os calcis, to be inserted into the base of the metatarsal bone of the little toe. Relations. — By its superficial surface with the peroneus longus and fascia of the leg and foot. By its deep surface with the fibula, the os calcis, and cuboid bone. The lateral relations are the same as those of the peroneus longus. The tendon of the peroneus brevis has but two tendinous sheaths and two synovial membranes, one behind the external malleolus and common to both peronei, the other upon the side of the os calcis. Actions. — The peronei muscles are extensors of the foot, conjointly with the tibialis posticus. They antagonize the tibialis anticus and pero- neus tertius, which are flexors of the foot. The whole of these muscles acting together, tend to maintain the flatness of the foot, so necessary to security in walking. FOOT. Dorsal Region. Extensor brevis digitorum, Interossei dorsales. The Extensor Brevis Digitorum muscle arises from the outer side of the os calcis, crosses the foot obliquely, and terminates in four tendons, the innermost of which is inserted into the base of the first phalanx of the great toe, and the other three into the sides of the long extensor tendons of the second, third, and fourth toes. Relations.—By its upper surface with the tendons of the extensor longus digitorum, peroneus brevis, and with the deep fascia of the foot. By its under surface with the tarsal and metatarsal bones. Its inner border is in relation with the dorsalis pedis artery, and the innermost tendon of the muscle crosses that artery just before its division. PLANTAR REGION. 259 The Dorsal Interossei muscles are placed between the metatarsal oones; they resemble the analogous muscles in the hand in arising by two heads from the adjacent sides of the metatarsal bones ; their tendons are inserted into the base of the first phalanx, and into the digital expan- sion of the tendons of the long extensor. The first dorsal interosseous is inserted into the inner side ofthe second toe, and is therefore an adductor; the other three are inserted into the outer side of the second, third, and fourth toes, and are consequently abductors. Relations. — By their upper surface with a strong fascia which separates them from the extensor tendons. By their under surface with the plantar interossei. Each of the muscles gives passage to a small artery (posterior perforating) which communicates with the external plantar artery. And between the heads of the first interosseous muscle the communicating artery of the dorsalis pedis takes its course. Fig. 136.-J- Plantar Region. First Layer. Abductor pollicis, Abductor minimi digiti, Flexor brevis digitorum. Dissection.—The sole of the foot is best dissected by carrying an inci- sion around the heel, and along the inner and outer borders of the foot, to * Dorsal interossei. 1. Abductor secundi. 2. Adductor secundi. 3. Adductor tertii. 4. Adductor quarti. . , , , t The first layer of muscles in the sole of the foot; this layer is exposed by the re- moval of the plantar fascia. 1. The os calcis. 2. The posterior part of the plantar fascia divided transversely. 3. The abductor pollicis. 4. The abductor minimi digiti. 5'The flexor brevis digitorum. 6. The tendon of the flexor longus pollicis muscle. 7 7 The lumbricales On the second and third toes, the tendons of the flexor longus digitorum are seen passing through the bifurcation of the tendons of the flexor brevis digitorum. 260 MUSCLES OF THE SOLE OF THE FOOT. Fig. 137. the great and little toes. This incision should divide the integument and superficial fascia, and both together should be dissected from the deep fascia, as far forward as the base of the phalanges, where they may be re- moved from the foot altogether. The deep fascia should then be removed, and the first layer of muscles will be brought into view. The Abductor Pollicis lies along the inner border of the foot; it arises by two heads, between which the tendons of the long flexors, arteries, veins, and nerves enter the sole of the foot. One head arises from the inner tuberosity of the os calcis, the other from the internal annular liga- ment and plantar fascia. Insertion, into the base of the first phalanx of the great toe, and into the internal sesamoid bone. Relations. — By its superficial surface with the internal portion of the plantar fascia. By its deep surface with the flexor brevis pollicis, musculus accessorius, tendons of the flexor longus digitorum and flexor longus pol- licis, tendons of the tibialis anticus and posticus, the plantar vessels and nerves, and the tarsal bones. On its outer border with the flexor brevis digitorum, from which it is separated by a vertical septum of the plantar fascia. The Abductor Minimi Digiti lies along the outer border of the sole of the foot. It arises from the outer tuberosity of the os calcis, and from the plantar fascia, as far forward as the base of the fifth metatarsal bone, and is inserted into the base of the first phalanx ofthe little toe. Relations. — By its superficial surface with the ex- ternal portion of the plantar fascia. By its deep sur- face with the musculus accessorius, flexor brevis minimi digiti, with the tarsal bones, and with the metatarsal bone of the little toe. By its inner side with the flexor brevis digitorum, from which it is se- parated by the vertical septum of the plantar fascia. The Flexor Brevis Digitorum (perforatus) is placed between the two preceding muscles. It arises from the under surface of the os calcis, from the plantar fascia and intermuscular septa, and is inserted by four tendons into the base of the second phalanx of the four lesser toes. Each tendon divides, pre- viously to its insertion, to give passage to the tendon ofthe long flexor ; hence its cognomen perforatus. Relations. — By its superficial surface with the plantar fascia. By its deep surface with a thin layer of fascia which separates it from the muscu- lus accessorius, tendons of the flexor longus digitorum and flexor longus pollicis, and plantar vessels and nerves. By its borders with the vertical septa of the plantar fascia, which separate the muscle, on the one side from the abductor pollicis, and on the other from the abductor minimi digiti. * The third and a part ofthe second layer of muscles ofthe sole ofthe foot. 1. The divided edge ofthe plantar fascia. 2. The musculus accessorius. 3. The tendon ofthe flexor longus digitorum. 4. The tendon of the flexor longus pollicis. 5. The flexor brevis pollicis. 6. The adductor pollicis. 7. The flexor brevis minimi digiti. h The transversus pedis. 9. Interossei muscles, plantar and dorsal. 10. Convex ridge formed by the tendon of the peroneus longus muscle in its oblique course across the foot. MUSCLES OF THE SOLE OF THE FOOT. 261 Second, Layer. Musculus accessorius. Lumbricales. Dissection. — The three preceding muscles must be divided from their origin, and anteriorly through their tendons, and removed, in order to bring into view the second layer. The Musculus Accessorius arises by two slips from either side of the under surface of the os calcis ; the inner slip being fleshy, the outer, ten- dinous. The muscle is inserted into the outer side and upper surface of the tendon of the flexor longus digitorum. Relations. — By its superficial surface, with the three muscles of the superficial layer, from which it is separated by their fascial sheaths, and with the external plantar vessels and nerves. By its deep surface, with the under surface of the os calcis and the long calcaneo-cuboid ligament. The Lumbricales (lumbricus, an earthworm) are four little muscles, arising from the tibial side of the tendons of the flexor longus digitorum, and inserted into the expansion ofthe extensor tendons, and into the base ofthe first phalanx ofthe four lesser toes. Relations.—By their superficial surface, with the Fig. 138* tendons of the flexor brevis digitorum. By their deep surface, with the third layer of muscles of the sole of the foot. They pass between the digital slips of the deep fascia to reach their insertion. Third Layer. Flexor brevis pollicis. Adductor pollicis, Flexor brevis minimi digiti, Transversus pedis. Dissection. — The tendons of the long flexors, and the muscles connected with them, must be removed, to see clearly the attachments of the third layer. The Flexor Brevis Pollicis arises, by a pointed tendinous process, from the side of the cuboid, and from the external cuneiform bone; it is inserted, by two heads, into the base of the first phalanx of the great toe. Two sesamoid bones are developed in the tendons of insertion of these two heads, and the tendon of the flexor longus pollicis lies in the groove between them. Relations.—By its superficial surface, with the abductor pollicis, tendon ofthe flexor longus pollicis, and plantar fascia. By its deep surface, with the tarsal bones and their ligaments, the metatarsal bone of the great toe, and the insertion ofthe tendon ofthe peroneus longus. By its inner bor- der, with the abductor pollicis ; and by its outer border, with the adductor pollicis; with both of these muscles it is blended near its insertion. The Adductor Pollicis arises from the cuboid bone, from the sheath of the tendon of the peroneus longus, and from the base of the third and * Deep-seated muscles in the sole ofthe foot. 1. Tendon ofthe flexor longus pollicis. 2. Tendon of the flexor communis digitorum pedis. 3. Flexor accessorius. 4, 4. Lum- bricales. 5. Flexor brevis digitorum. 6. Flexor brevis pollicis pedis. 7. Flexor brevis minimi digiti pedis. 262 MUSCLES OF THE SOLE OF THE FOOT. fourth metatarsal bones. It is inserted into the base of the first phalanx of the great toe. Relations. — By its superficial surface, with the tendons of the flexor longus and flexor brevis digitorum, the musculus accessorius, and lumbri- cales. By its deep surface, with the tarsal bones and ligaments, the exter- nal plantar artery and veins, the interossei muscles, tendon of the peroneus longus, and metatarsal bone of the great toe. By its inner border, with the flexor brevis pollicis; with which its fibres are blended. The Flexor Brevis Minimi Digiti arises Srom the base ofthe metatar- sal bone of the little toe, and from the sheath of the tendon of the peroneus longus. It is inserted into the base of the first phalanx ofthe little toe. Relations. — By its superficial surface, with the tendons of the flexor longus and flexor brevis digitorum, the fourth lumbricalis, abductor minimi digiti, and plantar fascia. By its deep surface, with the plantar interosseous muscle of the fourth metatarsal space, and the metatarsal bone. The Transversus Pedis arises, by fleshy slips, from the heads of the metatarsal bones of the four lesser toes. Its tendon is inserted into the base of the first phalanx of the great toe, being blended with that of the adductor pollicis. Relations. — By its superficial surface, with the tendons of the flexor longus and flexor brevis digitorum, and the lumbricales. By its deep surface, with the interossei, and heads of the metatarsal bones. Fourth Layer. Interossei plantares. The Plantar Interossei muscles are three in number, and are placed upon, rather than between, the metatarsal bones. They arise from the base of the metatarsal bones of the three outer toes, and are inserted into the inner side of the extensor tendon and base of the first phalanx of the same toes. Relations. — By their superficial surface, with the dorsal interossei and the metatarsal bones. By their deep surface, with the external plantar artery and veins, the adductor pollicis, transversus pedis, and flexor mi- nimi digiti. Actions.—All the preceding muscles act upon the toes ; and the move- ments which they are capable of executing may be referred to four heads, viz., flexion, extension, adduction, and abduction. In these actions they are grouped in the following manner:— Flexion. Extension. Flexor longus digitorum, Extensor longus digitorum, Flexor brevis digitorum, Extensor brevis digitorum. Flexor accessorius, Flexor minimi digiti. Adduction. Abduction. Interossei \ one dorsa'> Interossei, three dorsal, ' I three plantar. Abductor minimi digiti. THE FASCLE. 263 The great toe, like the thumb in the hand, enjoys an Fig. 139* independent action, and is provided with distinct mus- cles to perform its movements. These movements are precisely the same as those of the other toes, viz.: Flexion. Flexor longus pollicis, Flexor brevis pollicis. Extension. Extensor proprius pollicis, Extensor brevis digitorum. Adduction. Adductor pollicis. Abduction. Abductor pollicis. The only muscles excluded from this table are the lumbricales, four small muscles, which, from their at- tachments to the tendons of the long flexor, appear to be assistants to its action; and the transversus pedis, a small muscle placed transversely in the foot across the heads of the metatarsal bones, which has for its office the drawing together of the toes. CHAPTER V. ON THE FASCIAE. Fascia (fascia, a bandage) is the name assigned to laminae of various extent and thickness, which are distributed through the different regions ofthe body, for the purpose of investing or protecting the softer and more delicate organs. From a consideration of their structure, these fasciae may be arranged into two groups: cellulo-fibrous fasciae, and aponeurotic fasciae. The cellulo-fibrous fascia is best illustrated in the common subcutaneous investment of the entire body, the superficial fascia. This structure is si- tuated immediately beneath the integument over every part of the frame, and is the medium of connexion between that layer and the deeper parts. It is composed of cellulo-fibrous tissue containing in its areolae an abun- dance of adipose cells. The fat being a bad conductor of caloric, serves to retain the warmth of the body ; wiiile it forms at the same time a yield- ing tissue, through which the minute vessels and nerves pass to the papil- lary layer ofthe skin, without incurring the risk of obstruction from injury or pressure upon the surface. By dissection, the superficial fascia maybe separated into two layers, between which are found the superficial or cu- * Plantar interossei. 1. Abductor tertii. 2. Abductor quarti. 3. Interosseous minimi digiti. 264 FASCIAE OF THE HEAD AND NECK. taneous vessels and nerves; as the superficial epigastric artery, the saphe- nous veins, the radial and ulnar veins, the superficial lymphatic vessels, also the cutaneous muscles, as the platysma myoides, orbicularis palpe- brarum, sphincter ani, &c. In other situations, the cellulo-fibrous fascia is found condensed into a strong and inelastic membrane, as is exemplified in the deep fascia of the neck, the thoracic, transversalis, and perineal fasciae, and the sheaths of vessels. The aponeurotic fascia is the strongest kind of investing membrane; it is composed of tendinous fibres, running parallel with each other, and connected by other fibres of the same kind passing in different directions. When freshly exposed, it is brilliant and nacreous, and is tough, inelastic, and unyielding. In the limbs it forms the deep fascia, enclosing and forming distinct sheaths to all the muscles and tendons. It is thick upon the outer and least protected side of the limb, and thinner upon its inner side. It is firmly connected to the bones, and to the prominent points of each region, as to the pelvis, knee, and ankle, in the low7er, and to the clavicle, scapula, elbow, and wrist, in the upper extremity. It assists the muscles in their action, by keeping up a tonic pressure on their surface; aids materially in the circulation of the fluids in opposition to the laws of gravity; and in the palm of the hand and sole of the foot is a powerful protection to the structures which enter into the composition of these re- gions. In some situations its tension is regulated by muscular action, as by the tensor vaginas femoris and gluteus maximus in the thigh, by the biceps in the leg, and by the biceps and palmaris longus in the arm ; in other situations it affords an extensive surface for the origin of the fibres of muscles. The fasciae may be arranged like the other textures ofthe body into, 1. Those of the head and neck. 2. Those of the trunk. 3. Those of the upper extremity. 4. Those of the lower extremity. FASCIiE OF THE HEAD AND NECK. The Temporal Fascia is a strong aponeurotic membrane which covers in the temporal muscle at each side of the head, and gives origin by its internal surface to some of its muscular fibres. It is attached to the whole extent of the temporal ridge above, and to the zygomatic arch below; in the latter situation it is thick and divided into two layers, the external being connected to the upper border of the arch, and the internal to its inner surface. A small quantity of fat is usually found between these two layers, together with the orbital branch of the temporal artery. Cervical Fascia.—The fasciae of the neck are the superficial and the deep. The superficial cervical fascia is a part of the common superficial fascia of the entire body, and is only interesting from containing between its layers the platysma myoides muscle. The deep cervical fascia is a strong cellulo-fibrous layer which invests the muscles ofthe neck, and retains and supports the vessels and nerves. It commences posteriorly at the ligamentum nuchas, and passes forwards at each side beneath the trapezius muscle to the posterior border of the sterno-mastoid ; here it divides into two layers, which embrace that muscle and unite upon its anterior border to be prolonged onwards to the middle line of the neck, where it becomes continuous with the fascia of the oppo- site side. Besides thus constituting a sheath for the sterno-mastoid, it FASCIAE OF THE TRUNK. 265 also forms sheaths for the other muscles of the neck over which it passes. If the superficial layer of the sheath of the sterno-mastoid be traced up- wards, it will be found to pass over the parotid gland and masseter muscle, and to be inserted into the zygomatic arch ; and if it be traced downwards, it Fig- 140-* will be seen to pass in front of the clavi- cle, and become lost upon the pectoralis major muscle. If the deep layer of the sheath be examined superiorly, it will be found attached to the styloid process, from which it is reflected to the angle of the lower jaw, forming the stylo-maxil- lary ligament; and if it be followed downwards, it will be found connected with the tendon of the omo-hyoid mus- cle, and may thence be traced behind the clavicle, where it encloses the sub- clavius muscle, and, being extended from the cartilage of the first rib to the coracoid process, constitutes the costo- coracoid membrane. In front of the sterno-mastoid muscle, the deep fascia is attached to the border ofthe lower jaw and os hyoides, and forms a distinct sheath for the submaxillary gland. Inferiorly it divides into two layers, one of which passes in front of the sternum, while the other is at- tached to its superior border. FASCIA OF THE TRUNK. The thoracic fascia\ is a dense layer of cellulo-fibrous membrane, stretched horizontally across the superior opening of the thorax. It is firmly attached to the concave margin of the first rib, and to the inner surface of the sternum. In front it leaves an opening for the connexion of the cervical with the thoracic portion of the thymus gland, and behind it forms an arch across the vertebral column, to give passage to the oesophagus. At the point where the great vessels and trachea pass through the tho- racic fascia, it divides into an ascending and descending layer. The *A transverse section ofthe neck, showing the deep cervical fascia and its numerous prolongations, forming sheaths for the different muscles. As the figure is symmetrical, the figures of reference are placed only on one side. 1. The platysma myoides. 2. The trapezius. 3. The ligamentum nucha;, from which the fascia may be traced for- wards beneath the trapezius, enclosing the other muscles of the neck. 4. The point at which the fascia divides, to form a sheath for the sterno-mastoid muscle (5). 6. The point of reunion of the two layers of the sterno-mastoid sheath. 7. The point of union ofthe deep cervical fascia of opposite sides of the neck. 8. Section ofthe sterno-hyoid. 9. Omo-hyoid. 10. Sterno-thyroid. 11. The lateral lobe of the thyroid gland. 12. The trachea. 13. The oesophagus. 14. The sheath containing the common carotid artery, internal jugular vein, and pneumogastric nerve. 15. The longus colli. The nerve in front of the sheath of this muscle is the sympathetic. 16. The rectus anticus major. 17. Scalenus anticus. 18. Scalenus posticus. 19. The splenius capitis. 20. Splenius colli. 21. Levator anguli scapuke. 22. Complexus. 23. Trachelo-mastoid. 24. Trans- versalis colli. 25. Cervicalis ascendens. 26. The semi-spinalis colli. 27. The multi- fidus spinae. 2S. A cervical vertebra. The transverse processes are seen to be traversed by the vertebral artery and vein. f For an excellent description of this fascia, see Sir Astley Cooper's work on the "Anatomy of the Thymus Gland." 23 266 ABDOMINAL FASCLE. ascending layer is attached to the trachea, and, becomes continuous with the sheath of the carotid vessels, and with the deep cervical fascia : ihe descending layer descends upon the trachea to its bifurcation, surrounds the large vessels arising from the arch of the aorta, and the upper part of the arch itself, and is continuous with the fibrous layer of the pericardium. It is connected also with the venae innominatse and superior cava, and is attached to the cellular capsule of the thymus gland. " The thoracic fascia," writes Sir Astley Cooper, " performs three im- portant offices:— "1st. It forms the upper boundary of the chest, as the diaphragm does the lower. " 2d. It steadily preserves the relative situation ofthe parts which enter and quit the thoracic opening. " 3d. It attaches and supports the heart in its situation, through the medium of its connexion with the aorta and large vessels which are placed at its curvature." ABDOMINAL FASCIA. The lower part of the parietes of the abdomen, and the cavity of the pelvis, are strengthened by a layer of fascia which lines their internal sur- face, and at the bottom ofthe latter cavity is reflected inwards to the sides of the bladder. This fascia is continuous throughout the w7hole of the above-mentioned surface; but for convenience of description is considered under the several names of transversalis fascia, iliac fascia, and pelvic fascia; the two former meet at the crest of the ilium and Poupart's liga- ment, and the latter is confined to the cavity of the true pelvis. The fascia transversalis (Fascia Cooperi)* is a cellulo-fibrous lamella, which lines the inner surface of the transversalis muscle. It is thick and dense below, near the lower part of the abdomen ; but becomes thinner as it ascends, and is gradually lost in the subserous cellular tissue. It is attached inferiorly to the reflected margin of Poupart's ligament and to the crest of the ilium; internally, to the border of the rectus muscle; and, at the inner third of the femoral arch, is continued beneath Poupart's liga- ment, and forms the anterior segment of the crural canal, or sheath of the femoral vessels. The internal abdominal ring is situated in this fascia, at about midway between the spine of the os pubis and the anterior superior spine of the ilium, and half an inch above Poupart's ligament; it is bounded upon its inner side by a well-marked falciform border, but is ill defined around its outer margin. From the circumference of this ring is given off an infundi- buliform process, which surrounds the testicle and spermatic cord, consti- tuting the fascia propria of the latter, and forms the first investment to the sac of oblique inguinal hernia. It is the strength of this fascia, in the in- terval between the tendon of the rectus and the internal abdominal ring, that defends this portion of the parietes from the frequent occurrence of direct inguinal hernia. INGUINAL HERNIA. Inguinal hernia is of two kinds, oblique and direct. In Oblique Inguinal Hernia the intestine escapes from the cavity of * Sir Astley Cooper first described this fascia in its important relation to inguinal hernia. INGUINAL HERNIA. 267 the abdomen into the spermatic canal, through the internal abdominal ring, pressing before it a pouch of peritoneum which constitutes the hernial sac, and distending the infundibuliform process of the transversalis fascia. After emerging through the internal abdominal ring, it passes first beneath the lower and arched border of the transversalis muscle; then beneath the lower border of the internal oblique muscle; and finally through the ex- ternal abdominal ring in the aponeurosis of the external oblique. From the transversalis muscle it receives no investment; while passing beneath the lower border of the internal oblique it obtains the cremaster muscle; and, upon escaping at the external abdominal ring, receives the inter- columnar fascia. So that the coverings of an oblique inguinal hernia, after it has emerged through the external abdominal ring, are, from the surface to the intestine, the Integument, Cremaster muscle, Superficial fascia, Transversalis, or infundibuliform fascia, Intercolumnar fascia, Peritoneal sac. The spermatic canal, which, in the normal condition of the abdominal parietes serves for the passage of the spermatic cord in the male, and the round ligament with its vessels in the female, is about one inch and a half in length. It is bounded in front by the aponeurosis of the external oblique muscle; behind by the transversalis fascia, and the conjoined ten- don of the internal oblique and transversalis muscle; above by the arched borders of the internal oblique and transversalis; below by the grooved border of Poupart's ligament, and at each extremity by one of the abdo- minal rings, the internal ring at the inner termination, the external ring at the outer extremity. These relations may be more distinctly illustrated by the following plan— Above. Lower borders of internal oblique and transversalis muscle. In Front. ____________________________ Behind. . . Transversalis fascia. Aponeurosis of exter- c .. , n ■ ■ , . , r r . , .. Spermatic canal. Conjoined tendon of nal oblique. j____________""-____________ internal oblique and transversalis. Below. Grooved border of Poupart's ligament. There are three varieties of oblique inguinal hernia:—common, congen- ital, and encysted. Common oblique hernia is that which has been described above. Congenital hernia results from the nonclosure of the pouch of peritoneum carried downwards into the scrotum by the testicle, during its descent in the foetus. The intestine at some period of life is forced into this canal, and de- scends through it into the tunica vaginalis where it lies in contact with the testicle; so that congenital hernia has no proper sac, but is contained within the tunica vaginalis. The other coverings are the same as those of common inguinal hernia. Encysted hernia (hernia infantilis, of Hey) is that form of protrusion in which the pouch of peritoneum forming the tunica vaginalis, being only partially closed, and remaining open externally to the abdomen, admits 268 FASCIA ILIACA—FASCIA PELVICA. of the hernia passing into the scrotum, behind the tunica vaginalis. So that the surgeon in operating upon this variety, requires to divide three layers of serous membrane ; the first and second layers being those of the tunica vaginalis; and the third the true sac of the hernia. Direct Inguinal Hernia has received its name from passing directly through the external abdominal ring, and forcing before it the opposing parietes. This portion of the wall of the abdomen is strengthened by the conjoined tendon of the internal oblique and transversalis muscle, which is pressed before the hernia, and forms one of its investments. Its cover- ings are, the Integument, Conjoined tendon, Superficial fascia, Transversalis fascia, Intercolumnar fascia, Peritoneal sac. Direct inguinal hernia differs from oblique in never attaining the same bulk, in consequence of the resisting nature of the conjoined tendon of the internal oblique and transversalis and of the transversalis fascia; in its di- rection, having a tendency to protrude from the middle line rather than towards it. Thirdly, in making for itself a new passage through the ab- dominal parietes, instead of following a natural channel; and fourthly, in the relation of the neck of its sac to the epigastric artery ; that vessel lying to the outer side of the opening of the sac of direct hernia, and to the inner side of that of oblique hernia. All the forms of inguinal hernia are designated scrotal, when they have descended into that cavity. The Fascia Iliaca is the aponeurotic investment of the psoas and iliacus muscles; and, like the fascia transversalis, is thick below, and becomes gradually thinner as it ascends. It is attached superiorly along the edge of the psoas, to the anterior lamella of the aponeurosis of the transversalis muscle, to the ligamentum arcuatum internum, and to the bodies of the lumbar vertebras, leaving arches corresponding with the constricted portions of the vertebrae for the passage of the lumbar vessels. Lower down it passes beneath the external iliac vessels, and is attached along the margin of the true pelvis; externally, it is connected to the crest of the ilium; and, inferiorly, to the outer two-thirds of Poupart's ligament, where it is continuous with the fascia transversalis. Passing beneath Poupart's liga- ment, it surrounds the psoas and iliacus muscles to their termination, and beneath the inner third of the femoral arch forms the posterior segment of the sheath of the femoral vessels. The Fascia Pelvica is attached to the inner surface of the os pubis, and along the margin of the brim of the pelvis, where it is continuous with the iliac fascia. From this extensive origin it descends into the pel- vis, and divides into twro layers, the pelvic and obturator. The pelvic layer or fascia, when traced from the internal surface of the os pubis near the symphysis, is seen to be reflected inwards to the neck of the bladder, so as to form the anterior vesical ligaments. Traced backwards, it passes between the sacral plexus of nerves and the internal iliac vessels, and is attached to the anterior surface of the sacrum; and followed from the sides of the pelvis, it descends to the base of the bladder and divides into three layers, one, ascending, is reflected upon the side of that viscus, encloses the vesical plexus of veins, and forms the lateral liga- ments of the bladder. A middle layer passes inwards between the base PERINEAL FASCIAE. 269 of the bladder and the upper surface of the rectum, and was named by Mr. Tyrrell the recto-vesical fascia; and an inferior layer passes behind the rectum, and, with the layer of the opposite side, completely invests that intestine. Fig. I4i.« The obturator fascia passes directly downwards from the splitting of the layers ofthe pelvic fascia, and covers in the obturator internus muscle and the internal pudic vessels and nerve ; it is attached to the ramus of the os pubis and ischium in front, and below7 to the falciform margin of the great sacro-ischiatic ligament. Lying between these two layers of fascia is the levator ani muscle, which arises from their angle of separa- tion. The levator ani is covered in inferiorly by a third layer of fascia, which is given off by the obturator fascia, and is continued downwrards upon the inferior surface of the muscle to the extremity of the rectum, where it is lost. This layer may be named, from its position and inferior attachment, the anal fascia. Perineal Fascia.—In the perineum there are two fasciae of much im- portance, the superficial and deep perineal fascia. The superficial perineal fascia is a thin aponeurotic layer, which covers in the muscles of the genital portion of the perineum and the root of the penis. It is firmly attached at each side to the ramus of the os pubis and ischium; posteriorly,it is reflected backwards beneath the transversi perinei muscles, to become connected with the deep perineal fascia; while ante- riorly it is continuous with the dartos of the scrotum. The deep perineal fascia (Camper's ligament, triangular ligament) is situated behind the root of the penis, and is firmly stretched across be- tween the ramus of the os pubis and ischium of each side, so as to con- stitute a strong septum of defence to the outlet of the pelvis. At its infe- * A transverse section of the pelvis, showing the distribution of the pelvic fascia. 1. The bladder. 2. The vesicula seminalis of one side, divided across. 3. The rectum. 4. The iliac fascia, covering in the iliacus and psoas muscles (5) ; and forming a sheath for the external iliac vessels (6). 7. The anterior crural nerve, excluded from the sheath. 8. The pelvic fascia. 9. Its ascending layer, forming the lateral ligament of the bladder of one side, and a sheath to the vesical plexus of veins. 10. The recto- vesical fascia of Mr. Tyrrell, formed by the middle layer. 11. The inferior layer sur- rounding the rectum and meeting at the middle line with the fascia of the opposite side. 12. The levator ani muscle. 13. The obturator internus muscle, covered in by the ob- turator fascia, which also forms a sheath for the internal pudic vessels and nerve (14). 15. The layer of fascia which invests the under surface of the levator ani muscle, the anal fascia. 23* 270 PERINEAL FASCLE. rior border it divides into two layers, one of which is continued forwards, and is continuous with the superficial perineal fascia; while the other is Fig. 142* prolonged backwards to the rectum, and, joining with the anal fascia, assists in supporting the extremity of that intestine. The deep perineal fascia is composed of two layers, which are separated from each other by several important parts, and traversed by the membranous portion of the urethra. The anterior layer is nearly plane in its direction, and sends a sheath forwards around the anterior termination of the membranous ure- thra, to be attached to the posterior part ofthe bulb. The posterior layer is oblique, and sends a funnel-shaped process backwards, which invests the commencement of the mem- branous urethra and the prostate gland. The inferior segment of this funnel-shaped process is continued backward beneath the prostate gland and the vesiculae seminales, and is continuous with the recto-vesical fasciae of Tyr- rell, which is attached poste- riorly to the recto-vesical fold of peritoneum, and serves the important office of retaining that duplicative in its proper situa- tion. * The pubic arch with the attachments of the perineal fasciae. 1, 1, 1. The superfi- cial perineal fascia divided by a ^ shaped incision into three flaps ; the lateral flaps are turned over the ramus of the os pubis and ischium at each side, to which they are firmly attached; the posterior flap is continuous with the deep perineal fascia. 2. The deep perineal fascia. 3. The opening for the passage of the membranous portion of the urethra, previously to entering the bulb. 4. Two projections of the anterior layer ofthe deep perineal fascia, corresponding with the position of Cowpers glands. t A side view of the viscera of the pelvis, showing the distribution of the perineal and pelvic fasciae. 1. The symphysis pubis. 2. The bladder. 3. The recto-vesical fold of peritoneum, passing from the anterior surface of the rectum to the posterior part of the bladder; from the upper part of the fundus of the bladder it is reflected upon the Fig. 143.f FASCIAE OF THE UPPER EXTREMITY. 271 Between the two layers of the deep perineal fascia are situated, there- fore, the whole extent of the membranous portion of the urethra, the com- pressor urethrae muscle, Cowper's glands, the internal pudic and bulbous arteries, and a plexus of veins. Mr. Tyrrell considers the anterior lamella alone as the deep perineal fascia, and the posterior lamella as a distinct layer of fascia, covering in a considerable plexus of veins. FASCIA3 OF THE UPPER EXTREMITY. The superficial fascia of the upper extremity contains between its layers the superficial veins and lymphatics, and the superficial nerves. The deep fascia is thin over the deltoid and pectoralis major muscles, and in the axillary space, but thick upon the dorsum of the scapula, where it binds down the infra-spinatus muscle. It is attached to the clavicle, acromion process, and spine ofthe scapula. In the upper arm it is some- what stronger, and is inserted into the condyloid ridges, forming the, in- termuscular septa. In the fore-arm it is very strong, and at the bend of the elbow its thickness is augmented by a broad band, which is given off from the inner side of the tendon of the biceps. It is firmly attached to the olecranon process, to the ulna, and to the prominent points about the wrist. Upon the front ofthe wrist it is continuous with the anterior annu- lar ligament, which is considered by some anatomists to be formed by the deep fascia, but which I am more disposed to regard as a ligament of the wrist. On the posterior aspect of this joint, it forms a strong transverse band, the posterior annular ligament, beneath which the tendons of the extensor muscles pass, in distinct sheaths. The attachments of the pos- terior annular ligament are, the radius on one side, and the ulna and pisi- form bone on the opposite side of the joint. The tendons, as they pass beneath the annular ligaments, are surrounded by synovial bursae. The dorsum of the hand is invested by a thin fascia, which is continuous with the posterior annular ligament. The palmar fascia is divided into three portions. A central portion, which occupies the middle of the palm, and two lateral portions, w7hich spread out over the sides of the hand, and are continuous with the dorsal fascia. The central portion is strong and tendinous: it is narrow7 at the wrist, where it is attached to the annular ligament, and broad over the heads ofthe metacarpal bones, where it divides into eight slips, which are inserted into the sides of the base of the first phalanx of each finger. The abdominal parietes. 4. The ureter. 5. The vas deferens crossing the direction of the ureter. 6. The vesicula seminalis of the right side. 7, 7. The prostate gland divided by a longitudinal section. 8, 8. The section of a ring of elastic tissue encircling the prostatic portion of the urethra at its commencement. 9. The prostatic portion of the urethra. 10. The membranous portion, enclosed by the compressor urethrae muscle. 11. The commencement of the corpus spongiosum penis, the bulb. 12. The anterior ligaments ofthe bladder, formed by the reflection ofthe pelvic fascia, from the internal surface ofthe os pubis to the neck ofthe bladder. 13. The edge ofthe pelvic fascia at the point where it is reflected upon the rectum. 14. An interval between the pelvic fascia and deep perineal fascia, occupied by a plexus of veins. 15. The deep perineal fascia; its two layers. 16. Cowper's gland of the right side, situated between the two layers below the membranous portion of the urethra. 17. The superficial perineal fascia, ascending in front of the root of the penis to become continuous with the dartos ofthe scrotum (18). 19. The layer ofthe deep fascia which is prolonged to the rectum. 20. The lower part of the levator ani; its fibres are concealed by the anal fascia. 21. The inferior segment of the funnel-shaped process given off from the posterior layer of the deep perineal fascia, which is continuous with the recto-vesical fascia of Tyrrell. The attachment of this fascia to the recto-vesical fold of peritoneum is seen at 22. 272 FASCIA OF THE LOWER EXTREMITY. fascia is strengthened at its point of division into slips, by strong fasciculi of transverse fibres, and the arched interval left between the slips gives passage to the tendons of the flexor muscles. The arches between the fingers transmit the digital vessels and nerve, and lumbricales muscles. F ASCI AD OF THE LOWER EXTREMITY. The superficial fascia contains between its two layers the superficial vessels and nerves of the lower extremity. At the groin these two layers are separated from each other by the superficial lymphatic glands, and the deep layer is attached to Poupart's ligament, while the superficial layer is continuous with the superficial fascia of the abdomen. The deep fascia of the thigh is named, from its great extent, the fascia lata; it is thick and strong upon the outer side of the limb, and thinner upon its posterior side. That portion of fascia which invests the gluteus maximus is very thin, but that which covers in the gluteus medius is ex- cessively thick, and gives origin by its inner surface, to the superficial fibres of that muscle. The fascia lata is attached superiorly to Poupart's ligament, the crest of the ilium, sacrum, coccyx, tuberosity of the ischium, ramus of the ischium, and pubes ; in the thigh it is inserted into the linea aspera, and around the knee is connected with the prominent points of that joint. It possesses also two muscular attachments, by means of the tensor vaginae femoris, which is inserted between its two layers on the outer side, and the gluteus maximus, which is attached to it behind. In addition to the smaller openings in the fascia lata which transmit the small cutaneous vessels and nerves, there exists at the upper and inner extremity of the thigh, an oblique foramen, which gives passage to the superficial lymphatic vessels, and the large subcutaneous vein of the lower extremity, the internal saphenous vein, and is thence named the saplienous opening. The existence of this opening has given rise to the division of the upper part of the fascia lata into two portions, an iliac portion and a pubic portion. The iliac portion is situated upon the iliac side of the opening. It is attached to the crest of the ilium, and along Poupart's ligament to the spine of the os pubis, whence it is reflected downwards and outwards, in an arched direction, and forms a falciform border, which constitutes the outer boundary of the saphenous opening. The edge of this border im- mediately overlies, and is reflected upon the sheath ofthe femoral vessels, and the low7er extremity of the curve is continuous with the pubic portion. The pubic portion, occupying the pubic side of the saphenous opening, is attached to the spine of the os pubis and pectineal line; and, passing outw7ards behind the sheath of the femoral vessels, divides into two layers; the anterior layer is continuous with that portion of the iliac fascia which forms the sheath of the iliacus and psoas muscles, and the posterior layer is lost upon the capsule of the hip joint. The interval between the falciform border of the iliac portion and the opposite surface of the pubic portion is closed by a fibrous layer, which is pierced by numerous openings for the passage of lymphatic vessels, and is thence named cribriform fascia. The cribriform fascia is connected with the sheath of the femoral vessels, and forms one of the coverings of femoral hernia. When the iliac portion of the fascia lata is removed from its at- tachment to Poupart's ligament and is turned aside, the sheath of the femoral vessels (the femoral or crural canal) is brought into view; and if FEMORAL HERNIA. 273 Poupart's ligament be carefully Fig. U4.« divided, the sheath may be isolated, and its continuation with the trans- versalis and iliac fascia clearly de- monstrated. In this view the sheath of the femoral vessels is an infundi- buliform continuation of the abdo- minal fasciae, closely adherent to the vessels a little way down the thigh, but much larger than the vessels it contains at Poupart's ligament. If the sheath be opened, the artery and vein will be found lying side by- side, and occupying the outer two- thirds of the sheath, leaving an in- fundibuliform interval between the vein and the inner wall ofthe sheath. The superior opening of this space is named the femoral ring; it is bounded in front by Poupart's ligament, behind by the os pubis, internally by Gimbernat's ligament, and externally by the femoral vein. The interval itself serves for the passage ofthe super- ficial lymphatic vessels from the saphenous opening to a lymphatic gland, which generally occupies the femoral ring; and from thence they proceed into the current of the deep lymphatics. The femoral ring is closed merely by a thin layer of subserous areolar tissue,f which retains the lymphatic gland in its position, and is named septum crurale; and by the peritoneum. It follows from this description, that the femoral ring must be a weak point in the parietes ofthe abdomen, particularly in the female, where the femoral arch, or space included between Poupart's ligament and the border of the pelvis, is larger than in the male, while the structures which pass through it are smaller. It happens consequently, that, if violent or continued pressure be made upon the abdominal viscera, a portion of intestine may be forced through the femoral ring into the infundibuliform space in the sheath of the femoral vessels, carrying before it the peritoneum and the septum crurale,— this constitutes femoral hernia. If the causes which give rise to the formation of this hernia continue, the intestine, unable to extend further down the sheath, from the close connexion of the latter with the vessels, will in the next place be forced forwards through the saphenous opening in the fascia lata, carrying before it two additional coverings, the sheath of the vessels, or fascia propria, and the cribriform * A section of the structures which pass beneath the femoral arch. 1. Poupart's lig - ment. 2, 2. The iliac portion of the fascia lata, attached along the margin of the cre-t of the ilium, and along Poupart's ligament, as far as the spine of the os pubis (3). 4. The pubic portion of the fascia lata, continuous at 3 with the iliac portion, and passing outwards behind the sheath of the femoral vessels to its outer border at 5, where it divides into two layers ; one is continuous with the sheath of the psoas (6) and iliacn.s (7) ; the other (N) is lost upon the capsule of the hip joint (9). 10. The crural nervi\ enclosed in the sheath of the psoas and iliacus. 11. Gimbernat's ligament. 12. The femoral ring, within the femoral sheath. 13. The femoral vein. 14. The femoral ar- tery; the two vessels and the ring are surrounded by the femoral sheath, and thin septa are sent between the anterior and posterior wall ofthe sheath, dividing the artery from the vein, and the vein from the femoral ring. f This areolar tissue is sometimes very considerably thickened by a deposit of fat within its areolsp, and forms a thick stratum over the hernial sac. S 274 FASCIAE OF THE LEG. fascia ; and then curving upwards over Poupart's ligament, the hernia will become placed beneath the superficial fascia and integument. The direction which femoral hernia takes in its descent is at first down- wards, then forwards, and then upwards; and in endeavouring to reduce it, the application of the taxis must have reference to this course, and be directed in precisely the reverse order. The coverings of femoral hernia are the Integument, Fascia propria, Superficial fascia, Septum crurale, Cribriform fascia, Peritoneal sac. The Fascia of the leg is strong in the anterior tibial region, and gives origin by its inner surface to the upper part of the tibialis anticus, and ex- tensor longus digitorum muscles. It is firmly attached to the tibia and fibula at each side, and becomes thickened inferiorly into a narrow band, the anterior annular ligament, beneath which the tendons of the extensor muscles pass into the dorsum of the foot, in distinct sheaths lined by synovial bursas. Upon the outer side it forms a distinct sheath, which envelopes the peronei muscles, and ties them to the fibula. The anterior annular ligament is attached by one extremity to the outer side of the os calcis, and divides in front of the joint into two bands; one of which is inserted into the inner malleolus, while the other spreads over the inner side of the foot, and becomes con- tinuous with the internal portion of the plantar fascia. The fascia of the dorsum of the foot is a thin layer given off from the lower border of the anterior annular ligament: it is continuous at each side with the lateral portions of the plantar fascia. The fascia of the posterior part of the leg is much thinner than the ante- rior, and consists of two layers, superficial and deep. The superficial layer is continuous with the posterior fascia of the thigh, and is increased in thickness upon the outer side of the leg by an expansion derived from the tendon of the biceps; it terminates inferiorly in the external and in- ternal annular ligaments. The deep layer is stretched across between the tibia and fibula, and forms the intermuscular fascia between the superficial and deep layer of muscles. It covers in superiorly the popliteus muscle, receiving a tendinous expansion from the semi-membranosus muscle, and is attached to the oblique line of the tibia. The internal annular ligament is a strong fibrous band, attached above to the internal malleolus, and below to the side of the inner tuberosity of the os calcis. It is continuous above with the posterior fascia of the leg, and below with the plantar fascia, forming sheaths for the passage of the flexor tendons and vessels into the sole of the foot. The external annular ligament, shorter than the internal, extends from the extremity of the outer malleolus to the side of the os calcis, and serves to bind dow7n the tendons of the peronei muscles in their passage beneath the external ankle. The Plantar fascia consists of three portions, a middle and two lateral. The middle portion is thick and dense, and is composed of strong apo- neurotic fibres, closely interwoven with each other. It is attached poste- riorly to the inner tuberosity of the os calcis, and terminates under the heads of the metatarsal bones in five fasciculi. Each of these fasciculi ON THE ARTERIES. 275 divides into two slips, which are inserted one on each side into the bases of the first phalanges of the toes, leaving an interval between them for the passage of the flexor tendons. The point of division of this fascia into fasciculi and slips, is strengthened by transverse bands, which preserve the solidity of the fascia at its broadest part. The intervals between the toes give passage to the digital arteries and nerves, and to the lumbricales muscles. The lateral portions are thin, and cover the sides of the sole of the foot; they are continuous behind with the internal and external annular liga- ments ; on the inner side with the middle portion, and externally with the dorsal fascia. Besides constituting a strong layer of investment and defence to the soft parts situated in the sole of the foot, these three portions of fascia send processes inwards, which form sheaths for the different muscles. A strong septum is given off from each side of the middle portion of the plantar fascia, which is attached to the tarsal bones, and divides the muscles into three groups, a middle and two lateral; and transverse septa are stretched between these to separate the layers. The superficial layer of muscles derive a part of their origin from the plantar fascia. CHAPTER VI. ON THE ARTERIES. The arteries are the cylindrical tubes which convey the blood from the ventricles of the heart to every part of the body. They are dense in struc- ture, and preserve for the most part the cylindrical form when emptied of their blood, which is their condition after death: hence they were con- sidered by the ancients as the vessels for the transmission of the vital spirits,* and were therefore named arteries (olfy rr\esTv, to contain air). The artery proceeding from the left ventrical of the heart contains the pure or arterial blood, which is distributed throughout the entire system, and constitutes, with its returning veins, the greater or systemic circula- tion. That which emanates from the right ventricle, conveys the impure blood to the lungs; and, with its corresponding veins, establishes the lesser or pulmonary circulation. The whole of the arteries of the systemic circulation proceed from a single trunk, named the aorta, from which they are given off as branches, and divide and subdivide to their ultimate ramifications, constituting the great arterial tree which pervades, by its minute subdivisions, every part of the animal frame. The mode in which the division into branches takes place, is deserving of remark. From the aorta, the branches, for the most part, pass off at right angles, as if for the purpose of checking the impetus with which the blood w7ould otherwise rush along their cylinders from the main trunk; but in the limbs a very different arrangement is adopted; the branches are given off from the principal artery at an acute angle, so * To Galen is due the honour of having discovered that arteries contained blood, and not air. 276 GENERAL ANATOMY OF ARTERIES. that no impediment may be offered to the free circulation of the vital fluid. The division of arteries is usually dichotomous, as of the aorta into the two common iliacs, common carotid into the external and internal, &c.; but in some few instances a short trunk divides suddenly into several branches, which proceed in different directions; this mode of division is termed an axis, as the thyroid and coeliac axis. In the division of an artery into two branches, it is observed that the combined area? of the two branches are somewhat greater than that of the single trunk; and if the combined arese of all the branches at the peri- phery of the body were compared with that of the aorta, it would be seen that the blood, in passing from the aorta into the numerous distributino- branches, was flowing through a conical space, of which the apex might be represented by the aorta, and the base by the surface of the body. The advantage of this important principle in facilitating the circulation is sufficiently obvious; for the increased channel which is thus provided for the current of the blood, serves to compensate for the retarding influence of friction, resulting from the distance of the heart and the division ofthe vessels. Communications between arteries are very free and numerous, and in- crease in frequency with the diminution in size of the branches; so that, through the medium of the minute ramifications, the entire body may be considered as one uninterrupted circle of inosculations, or anastomoses (dva between, and for the constant divisions and communications which take place between them, without any alteration of size. They * I have a preparation, showing the collateral circulation in a dog, in which I tied the abdominal aorta; the animal died from over-feeding nearly two years after the operation. J STRUCTURE OF ARTERIES. 277 inosculate on the one hand with the terminal ramusculi of the arteries; and on the other with the minute radicles of the veins. Arteries are composed of three coats, external, middle, and internal. The external or areolo-fibrous coat is firm and strong, and serves at the same time as the chief means of resistance of the vessel, and of connection to surrounding parts. It consists of condensed areolo-fibrous tissue, strengthened by an interlacement of glistening fibres which are partly longitudinal and partly encircle the cylinder of the tube in an oblique direction. Upon the surface the areolar tissue is loose, to permit of the movements of the artery in distention and contraction. The middle coat is that upon which the thickness of the artery depends; it is yellowish in colour, and so brittle as to be cut through by the thread in the ligature of a vessel.* The internal coat is a thin serous membrane which lines the interior of the artery, and gives it the smooth polish which that surface presents. It is continuous with the lining membrane of the heart, and through the me- dium of the capillaries with that of the venous system. In intimate structure an artery is more complicated than the above de- scription would imply. The internal coat, for example, is composed of two layers, and the middle of three, so that, with the external coat, there are six layers entering into the composition of an artery. The innermost coat is a tesselated epithelium analogous to that of other serous membranes. The second coat from within is a thin, rigid membrane, pierced with a number of round or oval-shaped holes, and supporting a thin layer of flat, longitudinal fibres. From these characters it has been denominated the fenestrated or striated coat. The third layer, which is the innermost part of the middle coat, is composed of flat, longitudinal fibres, analogous to those of organic muscle. The fourth layer, the thickest of the whole, is composed of muscular fibres of organic life, arranged in a circular direc- tion around the vessel. The fifth, or outermost part of the middle coat, is a thin layer of elastic tissue; this is present only in the large arteries. The sixth is the external or areolo-fibrous coat. The arteries in their distribution through the body are included in a loose areolar investment which separates them from surrounding tissues, and is called a sheath. Around the principal vessels the sheath is an im- portant structure; it is composed of areolo-fibrous tissue, intermingled with tendinous fibres, and is continuous with the fasciae of the region in which the arteries are situated, as with the thoracic and cervical fasciae in the neck, transversalis and iliac fasciae, and fascia lata in the thigh, &c. The sheath of the arteries contains also their accompanying veins, and sometimes a nerve. The coats of arteries are supplied with blood like other organs of the body, and the vessels which are distributed to them are named vasa vaso- rum. They are also provided with nerves; but the mode of distribution ofthe nerves is at present unknown. In the consideration of the arteries, we shall first describe the aorta, and * The second or middle coat ofthe arteries has given rise to no little discussion among the continental anatomists. It will be found, however, to consist of fibres, flat, elastic, for the most part transverse, and belonging to the yellow elastic tissue. Some of the fibres are longitudinal, and some of the transverse present strong evidences of belonging to the muscular system of organic life ; so that the coat may, I think, be fairly stated to be a mixed one, composed of yellow, elastic, and organic muscular fibres. It Is beet studied in the aorta or some large trunk.—G. 24 278 AORTA. the branches of that trunk with their subdivisions, which together consti- tute the efferent portion of the systemic circulation; and then the pui. monary artery as the efferent trunk of the pulmonary circulation. Fig. 145.* The aorta arises from the left ventricle, at the middle ofthe root ofthe heart, and opposite the articulation of the fourth costal cartilage with the sternum. At its commencement it presents three dilatations, called the sinus aortici, which correspond with the three semilunar valves. It as- cends at first to the right, then curves backwards and to the left, and de- scends on the left side of the vertebral column to the fourth lumbar verte- bra. Hence it is divided into—ascending—arch—and descending aorta. * The large vessels which proceed from the root of the heart, with their relations; the heart has been removed. 1. The ascending aorta. 2. The arch. 3. The thoracic portion of the descending aorta. 4. The arteria innominata, dividing into, 5, the right carotid, which again divides at 6, into the external and internal carotid ; and 7, the right subclavian artery. 8. The axillary artery; its extent is designated by a dotted line. 9. The brachial artery. 10. The right pneumogastric nerve running by the side of the common carotid, in front of the right subclavian artery, and behind the root of the right lung. 11. The left common carotid, having to its outer side the left pneumo- gastric nerve, which crosses the arch of the aorta, and as it reaches its lower border is seen to give off the left recurrent nerve. 12. The left subclavian artery becoming axil- lary and brachial in its course, like the artery of the opposite side. 13. The trunk of the pulmonary artery connected to the concavity of the arch of the aorta by a fibrous cord, the remains of the ductus arteriosus. 14. The left pulmonary artery. 15. The right pulmonary artery. 16. The trachea. 17. The right bronchus. 18. The left bronchus. 19, 19. The pulmonary veins. 17, 15, and 19, on the right side, and 14, 18, and 19, on the left, constitute the roots ofthe corresponding lungs, and the relative posi- tion of these vessels is preserved. 20. Bronchial arteries. 21, 21. Intercostal arteries; the branches from the front of the aorta above and below the number 3 are pericardiac and oesophageal branches. ARCH OF THE AORTA. 279 Relations.—The ascending aorta has in relation with it, in front, the trunk of the pulmonary artery, thoracic fascia, and pericardium; behind, the right pulmonary veins and artery ; to the right side, the right auricle and superior cava; and to the left, the left auricle and the trunk of the pulmonary artery. Plan of the Relations of the Ascending Aorta. In Front. Pericardium, Thoracic fascia, Pulmonary artery. Right Side. Superior cava, Right auricle. Ascending Aorta. Left Side. Pulmonary artery. Left auricle. Behind. Right pulmonary artery, Right pulmonary veins. Arch.—The upper border of the arch of the aorta is parallel with th.: upper border of the second sterno-costal articulation of the right side hi front, and the second dorsal vertebra behind, and terminates opposite the lower border of the third. The anterior surface of the arch is crossed by the left pneumogastric nerve, and by the cardiac branches of that nerve and of the sympathetic. The posterior surface of the arch is in relation with the bifurcation of the trachea and great cardiac plexus, the cardiac nerves, left recurrent nerve, and the thoracic duct. The superior border gives off the three great arte- ries, viz. the innominata, left carotid, and left subclavian. The inferior border, or concavity of the arch, is in relation with the remains of the ductus arteriosus, the cardiac ganglion and left recurrent nerve, and has passing beneath it the right pulmonary artery and left bronchus. Plan ofthe Relations ofthe Arch ofthe Aorta. Above. Arteria innominata, Left carotid, Left subclavian. In Front. Left pneumogastric nerve, Cardiac nerves. Arch of the Aorta. Behind. Bifurcation of the trachea, Great cardiac plexus, Cardiac nerves, Left recurrent nerve, Thoracic duct. Below. Cardiac ganglion, Remains of ductus arteriosus, Left recurrent nerve, Right pulmonary artery, Left bronchus. The descending aorta is subdivided in correspondence with the two great cavities of the trunk, into the thoracic and abdominal aorta. 280 ABDOMINAL AORTA. The Thoracic aorta is situated to the left side of the vertebral column, but approaches the middle line as it descends, and at the aortic opening of the diaphragm is altogether in front of the column. After entering the abdomen it again falls back to the left side. Relations.—It is in relation, behind, with the vertebral column and lesser vena azygos ; in front, with, the oesophagus and right pneumogastric nerve; to the left side, with the pleura; and to the right, with the thoracic duct. Plan ofthe Relations ofthe Thoracic Aorta. In Front. CEsophagus, Right pneumogastric nerve. Right Side. Thoracic duct. Thoracic Aorta. Left Side. Pleura. Behind. Lesser vena azygos, Vertebral column. The Abdominal aorta enters the abdomen through the aortic opening of the diaphragm, and descends, lying rather to the left side of the verte- bral column, to the fourth lumbar vertebra, where it divides into the two common iliac arteries. Relations.—It is crossed in front, by the left renal vein, pancreas, trans- verse duodenum, and mesentery, and is embraced by the aortic plexus; behind it is in relation with the thoracic duct, receptaculum chyli, and left lumbar veins. On its left side is the left semilunar ganglion and sympathetic nerve ; and on the right, the vena cava, right semilunar ganglion, and the com- mencement of the vena azygos. Plan ofthe Relations ofthe Abdominal Aorta. In Front. Left renal vein, Pancreas, Transverse duodenum, Mesentery, Aortic plexus. Right Side. Vena cava, Right semilunar gan- glion, Vena azygos. Abdominal Aorta. Behind. Thoracic duct, Receptaculum chyli, Left lumbar veins. Left Side. Left semilunar gan- glion, Sympathetic nerve. ARTERIA innominata. 281 are, Branches.—The branches of the aorta, arranged into a tabular form, Ascending aorta Arch of the aorta Thoracic aorta Right carotid, Right subclavian. Abdominal aorta Coronary. Arteria innominata. Left carotid, Left subclavian. Pericardiac, Bronchial, CEsophageal, Intercostal. Phrenic, C Gastric, Ccelic axis, < Hepatic, ( Splenic. Supra-renal, Renal, Superior mesenteric, Spermatic, Inferior mesenteric. Lumbar, Sacramedia, Common iliacs. The Coronary arteries arise from the aortic sinuses at the commence- ment of the ascending aorta, immediately above the free margin or the semilunar valves. The left or anterior coronary, passes forwards, be- tween the pulmonary artery and left appendix auriculae, and divides into two branches; one of which winds around the base ofthe left venti'ple in the auriculo-ventricular groove, and inosculates with the right coronary, forming an arterial circle around the base of the heart; while the other passes along the line of union of the two ventricles, upon the anterior as- pect of the heart, to its apex, where it anastomoses with the descending branch of the right coronary. It supplies the left auricle and the anterior surface of both ventricles. The right, or posterior coronary, passes forwards, between the root of the pulmonary artery and the right auricle, and winds along the auriculo- ventricular groove, to the posterior median furrow, where it descends upon the posterior aspect of the heart to its apex, and inosculates with the left coronary. It is distributed to the right auricle, and to the posterior surface of both ventricles, and sends a large branch along the sharp margin of the right ventricle to the apex of the heart. ARTERIA INNOMINATA. The Arteria innominata (fig. 145, No. 4) is the first artery given off by the arch of the aorta. It is an inch and a half in length, and ascends obliquely towards the right sterno-clavicular articulation, where it divides into the right carotid and right subclavian artery. Relations.—It is in relation, in front, with the left vena innominata, the thvraus gland, and the origins of the sterno-thyroid and sterno-hyoid mus- cles, which separate it from the sternum. Behind, with the trachea, pneu- 24* 282 COMMON CAROTID ARTERIES. mogastric nerve and cardiac nerves; externally, with the right vena inno- minata and pleura; and internally, with the origin of the left carotid. Plan of the Relations of the Arteria Innominata. In Front. Left vena innominata, Thymus gland, Sterno-thyroid, Sterno-hyoid. Right Side. Right vena innominata, Pleura. Arteria innominata. Left Side. Left carotid. Behind. Trachea, Pneumogastric nerve, Cardiac nerves. The arteria innominata occasionally gives off a small branch, which ascends along the middle of the trachea to the thyroid gland. This branch was described by Neubauer, and Dr. Harrison names it the middle thyroid artery. A knowledge of its existence is important in performing the ope- ration of tracheotomy. COMMON CAROTID ARTERIES. The common carotid arteries (xa^a, the head,) arise, the right from the bifurcation of the arteria innominata opposite the right sterno-clavicular articulation, the left from the arch of the aorta. It follows, therefore, that the right carotid is shorter than the left; it is also more anterior; and, in consequence of proceeding from a branch instead of from the main trunk, it is larger than its fellow. The Right common carotid artery (fig. 145, No. 5) ascends the neck perpendicularly, from the right sterno-clavicular articulation to a level with the upper border of the thyroid cartilage, where it divides into the external and internal carotid. The Left common carotid (fig. 145, No. 11) passes somewhat obliquely outwards from the arch of the aorta to the side of the neck, and thence upwards to a level with the upper border of the thyroid cartilage, where it divides like the right common carotid into the external and internal carotid. Relations.—The right common carotid rests, first, upon the longus colli muscle, then upon the rectus anticus major, the sympathetic nerve being interposed. The inferior thyroid artery and recurrent laryngeal nerve pass behind it at its lower part. To its inner side is the trachea, recurrent laryngeal nerve, and larynx; to its outer side, and enclosed in the same sheath, the jugular vein and pneumogastric nerve; and in front, the sterno- thyroid, sterno-hyoid, sterno-mastoid, omo-hyoid, and platysma muscles, and the descendens noni nerve. The left common carotid, in addition to the relations just enumerated, which are common to both, is crossed near its commencement by the left vena innominata; it lies upon the trachea ; then gets to its side, and is in relation with the oesophagus and thoracic duct: to facilitate the study of these relations, I have arranged them in a tabular form. EXTERNAL CAROTID ARTERY. 283 Plan of Relations of the Common Carotid Artery. In Front. Platysma, Descendens noni nerve, Omo-hyoid, Sterno-mastoid, Sterno-hyoid, Sterno-thyroid. Externally. Internal jugular vein, Pneumogastric nerve. Common Carotid Artery. Internally. Trachea, Larynx, Recurrent laryngeal nerve. Behind. Longus colli, Rectus anticus major, Sympathetic, Inferior thyroid artery, Recurrent laryngeal nerve. Additional Relations of the Left Common Carotid. In Front. Behind. Internally. Externally Left vena innominata. Trachea, Thoracic duct. Arteria innominata, Oesophagus. Pie EXTERNAL CAROTID ARTERY. The External carotid artery ascends nearly perpendicularly from oppo- site the upper border of the thyroid cartilage, to the space between the neck ofthe lower jaw and the meatus auditorius, where it divides into the temporal and internal maxillary artery. Relations. —In front it is crossed by the posterior belly of the digas- tricus, stylo-hyoideus, and platysma myoides muscles; by the hypoglossal nerve' near its origin; higher up it is situated in the substance of the parotid gland, and is crossed by the facial nerve. Behind, it is separated from the internal carotid by the stylo-pharyngeus and stylo-glossus muscles, glosso-pharyngeal nerve, and part of the parotid gland. Plan of the Relations of the External Carotid Artery. In Front. Platysma, Digastricus, Stylo-hyoid, Hypoglossal nerve, Facial nerve, Parotid gland. External Carotid Artery. Behind. Stylo-pharyngeus, Stylo-glossus, Glosso-pharyngeal nerve, Parotid gland. 284 SUPERIOR THYROID ARTERY. Branches.—The branches of the external carotid are eleven in number, and may be arranged into four groups, viz. Anterior. 1. Superior thyroid, 2. Lingual, 3. Facial. Superior. 7. Ascending pharyngeal, 8. Parotidean, 9. Transverse facial. Posterior. 4. Mastoid, 5. Occipital, 6. Posterior auricular. Terminal. 10. Temporal, 11. Internal maxillary. The anterior branches arise from the commencement of the external carotid, within a short distance of each other. The lingual and facial bifurcate, not unfrequently, from a common trunk. 1. The Superior thyroid artery (the first of the branches of the ex- ternal carotid) curves downwards to the thyroid gland to wrhich it is dis- tributed, anastomosing with its fellow of the opposite side, and with the inferior thyroid arteries. In its course it passes beneath the omo-hyoid, sterno-thyroid, and sterno-hyoid muscles. Fig. 146.* Branches.—Hyoid, Superior laryngeal, Inferior laryngeal, Muscular. * The carotid arteries, with the branches of the external carotid. 1. The common carotid. 2. The external carotid. 3. The internal carotid. 4. The carotid foramen in the petrous portion of the temporal bone. 5. The superior thyroid artery. 6 The lin- gual artery. 7. The facial artery. 8. The mastoid artery. 9. The occipital 10 The posterior auricular. 11. The transverse facial artery. 12. The internal maxillary 13. Ihe temporal. 14. The ascending pharyngeal artery. LINGUAL AND FACIAL ARTERIES. 285 The Hyoid branch passes forwards beneath the thyro-hyoideus, and is distributed to the depressor muscles ofthe os hyoides near their insertion. The Superior laryngeal pierces the thyro-hyoidean membrane, in com- pany with the superior laryngeal nerve, and supplies the mucous mem- brane and muscles of the larynx, sending a branch upwards to the epiglottis. The Inferior laryngeal is a small branch which crosses the crico-thyroi- dean membrane along the lower border of the thyroid cartilage. It sends branches through the membrane, to supply the mucous lining ofthe larynx, and inosculates with its fellow of the opposite side. The Muscular branches are distributed to the depressor muscles of the os hyoides and larynx. One of these branches crosses the sheath of the common carotid to the under surface of the sterno-mastoid muscle. 2. The Lingual artery ascends obliquely from its origin, it then passes forwards parallel with the great cornu of the os hyoides; thirdly, it ascends to the under surface of the tongue; and, fourthly, runs forward in a serpentine direction to its tip (under the name of the ranine artery), where it terminates by inosculating with its fellow of the opposite side. Relations.—The first part of its course rests upon the middle constrictor muscle of the pharynx, being covered in by the tendon of the digastricus and the stylo-hyoid muscle; the second is situated between the middle constrictor and hyo-glossus muscle, the latter separating it from the hypo- glossal nerve; in the third part of its course it lies between the hyo-glossus and genio-hyo-glossus; and in the fourth (ranine) rests upon the lingualis to the tip of the tongue. Branches.—Hyoid, Dorsalis linguae, Sublingual. The Hyoid branch runs along the upper border of the os hyoides, and is distributed to the elevator muscles of the os hyoides near their origin, inosculating with its fellow of the opposite side. The Dorsalis lingua ascends along the posterior border of the hyo- glossus muscle to the dorsum of the tongue, and is distributed to the tongue, the fauces, and epiglottis, anastomosing with its fellow of the op- posite side. The Sublingual branch, sometimes considered as a branch of bifurca- tion of the lingual, runs along the anterior border of the hyo-glossus, and is distributed to the sublingual gland and to the muscles of the tongue. It is situated between the mylo-hyoideus and genio-hyo-glossus, generally accompanies Wharton's duct for a part of its course, and sends a branch to the fraenum linguae. It is the latter branch which affords the consider- able haemorrhage which sometimes follows the operation of snipping the fraenum in children. 3. Facial artery. — The Facial artery arises a little above the great cornu ofthe os hyoides, and descends obliquely to the submaxillary gland, in which it lies embedded. It then curves around the body of the lower jaw, close to the anterior inferior angle of the masseter muscle, ascends to the angle of the mouth, and thence to the angle of the eye, where it is named the angular artery. The facial artery is tortuous in its course 286 FACIAL ARTERY. over the buccinator muscle, to accommodate itself to the movements of the jaws. Relations. — Below the jaw it passes beneath the digastricus and stylo- hyoid muscles; on the body of the lower jaw it is covered by the platysma myoides, and at the angle of the mouth by the depressor anguli oris and zygomatic muscles. It rests upon the submaxillary gland, the lower jaw buccinator, orbicularis oris, levator anguli oris, levator labii superioris proprius, and levator labii superioris alaeque nasi. Its branches are divided into those which are given off below the jaw and those on the face : they may be thus arranged:— Below the Jaw.—Inferior palatine, Submaxillary, Submental, Pterygoid. On the Face.—Masseteric, Inferior labial, Inferior coronary, Superior coronary, Lateralis nasi. The Inferior palatine branch ascends between the stylo-glossus and stylo-pharyngeus muscles, to be distributed to the tonsil and soft palate, and anastomoses with the posterior palatine branch of the internal maxil- lary artery. The Submaxillary are four or five branches which supply the submaxil- lary gland. The Submental branch runs forwards upon the mylo-hyoid muscle, under cover ofthe body of the lower jaw7, and anastomoses with branches' ofthe sublingual and inferior dental artery. The Pterygoid branch is distributed to the internal pterygoid muscle. The Masseteric branches are distributed to the masseter and buccinator muscles. The Inferior labial branch is distributed to the muscles and integument ofthe lower lip. The Inferior coronary runs along the edge of the low7er lip, between the mucous membrane and the orbicularis oris; it inosculates with the cor- responding artery of the opposite side. The Superior coronary follows the same course along the upper lip, in- osculating with the opposite superior coronary artery, and at the middle of the hp it sends a branch upwards, to supply the septum of the nose and the mucous membrane. The Lateralis nasi is distributed to the ala and septum ofthe nose. The Inosculations of the facial artery are very numerous: thus it anas- tomoses with the sublingual branch of the lingual, with the ascending pharyngeal and posterior palatine arteries, with the inferior dental as it es- capes from the mental foramen, infra-orbital at the infra-orbital foramen, transverse facial on the side of the face, and at the angle of the eye with the nasal and frontal branches of the ophthalmic artery. The facial artery is subject to considerable variety in its extent: it not unfrequently terminates at the angle of the nose or mouth, and is rarely symmetrical on both sides of the face. TRANSVERSALIS FACIEI. 287 4. The Mastoid artery turns downwards from its origin, to be dis- tributed to the sterno-mastoid muscle, and to the lymphatic glands of the neck; sometimes it is replaced by two small branches. 5. The Occipital artery, smaller than the anterior branches, passes backwards beneath the posterior belly of the digastricus, the trachelo- mastoid and sterno-mastoid muscles, to the occipital groove in the mastoid portion of the temporal bone. It then ascends between the splenius and complexus muscles, and divides into two branches which are distributed upon the occiput, anastomosing with the opposite occipital, the posterior auricular, and temporal artery. The hypoglossal nerve curves around this artery near its origin from the external carotid. Branches.—It gives off only two branches deserving of name, the infe- rior meningeal and princeps cervicis. The Inferior meningeal ascends by the side ofthe internal jugular vein, and passes through the foramen lacerum posterius, to be distributed to the dura mater. The Arteria princeps cervicis is a large and irregular branch. It de- scends the neck between the complexus and semi-spinalis colli, and inos- culates with the profunda cervicis of the subclavian. This branch is the means of establishing a very important collateral circulation between the branches of the carotid and subclavian, after the ligature of the common carotid artery. 6. The Posterior auricular artery arises from the external carotid, above the level of the digastric and stylo-hyoid muscles, and ascends be- neath the lower border of the parotid gland, and behind the concha, to be distributed by two branches to the external ear and side of the head, anas- tomosing with the occipital and temporal arteries; some of its branches pass through fissures in the fibro-cartilage, to be distributed to the anterior surface of the pinna. The anterior auricular arteries are branches of the temporal. Branches.—The posterior auricular gives off but one named branch, the stylo-mastoid, which enters the stylo-mastoid foramen to be distributed to the aquseductus Fallopii and tympanum. 7. The Ascending pharyngeal artery, the smallest of the branches ofthe external carotid, arises from that trunk near its bifurcation, and as- cends between the internal carotid and the side ofthe pharynx to the base of the skull, where it divides into two branches; meningeal, which enters the foramen lacerum posterius, to be distributed to the dura mater; and pharyngeal. It supplies the pharynx, tonsils, and Eustachian tube. 8. The Parotidean arteries are four or five large branches which are given off from the external carotid whilst that vessel is situated in the pa- rotid gland. They are distributed to the structure of the gland, their ter- minal branches reaching the integument and the side ofthe face. 9. The Transversalis Faciei arises from the external carotid, whilst that trunk is lodged within the parotid gland; it crosses the massetei muscle, lying parallel with and a little above Stenon's duct; and is dis- tributed to the temporo-maxillary articulation, and to the muscles and in- 288 INTERNAL MAXILLARY ARTERY. tegument of the side of the face, inosculating with the infra-orbital and facial artery. This artery is not unfrequently a branch of the temporal. 10. The Temporal artery is one of the two terminal branches of the external carotid. It ascends over the root of the zygoma ; and, at about an inch and a half above the zygomatic arch, divides into an anterior and a posterior temporal branch. The anterior temporal is distributed over the front of the temple and arch of the skull, and anastomoses with the opposite anterior temporal, and with the supra-orbital and frontal artery. The posterior temporal curves upwards and backwards, and inosculates with its fellow of the opposite side, with the posterior auricular and occi- pital artery. The trunk of the temporal artery is covered in by the parotid gland and by the attrahens aurem muscle, and rests on the temporal fascia. Branches.—Orbitar, Anterior auricular, Middle temporal. The Orbitar artery is a small branch, not always present, which passes forward immediately above the zygoma, between the two layers of the temporal fascia, and inosculates beneath the orbicularis palpebrarum with the palpebral arteries. The Anterior auricular arteries are distributed to the anterior portion of the pinna. The Middle temporal branch passes through an opening in the temporal fascia immediately above the zygoma, and supplies the temporal muscle inosculating with the deep temporal arteries. 11. The Internal maxillary artery, the other terminal branch ofthe external carotid, has next to be examined. Dissection.—The Internal maxillary artery passes inwards behind the neck of the lower jaw to the deep structures in the face ; w7e require, therefore, to remove several parts for the purpose of seeing it completely. To obtain a good view of the vessel, the zygoma should be sawn across in front of the external ear, and the malar bone near the orbit. Turn down the zygomatic arch with the masseter muscle. In doing this, a small artery and nerve will be seen crossing the sigmoid notch of the lower jaw, and entering the masseter muscle (the masseteric). Cut away the tendon of the temporal muscle from its insertion into the coronoid process, and turn it upwards towards its origin ; some vessels will be seen entering its under surface; these are the deep temporal. Then saw the ramus of the jaw across its middle, and dislocate it from its articulation with the temporal bone. Be careful in doing this to carry the blade of the knife close to the bone, lest any branches of nerves should be injured. Next raise this portion of bone, and with it the external pterygoid muscle. The artery, together with the deep branches of the inferior maxillary nerve, will be seen lying on the pterygoid muscles. These are to be carefully freed from fat and areolar tissue, and then examined. This artery commences in the substance of the parotid gland, opposite the meatus auditorius externus ; it passes in the first instance horizontally forward behind the neck of the lower jaw ; next, curves around the lowei border of the external pterygoid muscle near its origin, and ascends ob- liquely forwards upon the outer side of that muscle ; it then passes between INTERNAL MAXILLARY ARTERY. 289 the two heads of the external pterygoid, and enters the pterygo-maxillary fossa. Occasionally it passes between the two pterygoid muscles, without appearing on the outer surface of the external ptery- goid. In consideration of its course, this artery may be divided into three portions: maxillary, pterygoid, and spheno-maxillary. Relations.—The maxillary portion is situated between the ramus of the jaw and the internal lateral ligament, lying parallel with the auricular nerve; the pterygoid portion between the external pterygoid muscle, and the masseter and temporal muscle. The pterygo-maxillary heads of the external pterygoid muscle, and is in relation with Meckel's ganglion. Branches. Maxillary Portion. Tympanic, Inferior dental, Arteria meningea media, Arteria meningea parva. Fig. 147.* portion lies between the two , in the spheno-maxillary fossa, Pterygoid Portion. Deep temporal branches, External pterygoid, Internal pterygoid, Masseteric, Buccal. Pterygo-maxillary Portion. Superior dental, Infra-orbital, Pterygo-palatine, Spheno-palatine, Posterior palatine, Vidian. The Tympanic branch is small, and not likely to be seen in an ordinary dissection; it is distributed to the temporo-maxillary articulation and meatus, and passes into the tympanum through the fissura Glaseri. The Inferior dental descends to the dental foramen, and enters the canal of the lower jaw in company with the dental nerve. Opposite the bicuspid teeth it divides into tw7o branches, one of which is continued on- wards within the bone as far as the symphisis, to supply the incisor teeth, * 1. The external carotid artery. 2. The trunk of the transverse facial artery. 3, 4. The two terminal branches of the external carotid. 3. The temporal artery; and 4. The internal maxillary, the first or maxillary portion of its course; the limit of this por- tion is marked by an arrow. 5. The second, or pterygoid portion, of the artery : the limits are bounded by the arrows. 6. The third or pterygo-maxillary portion. The branches ofthe maxillary portion are, 7. A tympanic branch. 8. The arteria meningea magna. 9. The arteria meningea parva. 10. The inferior dental artery. The branches of The second portion are wholly muscular, the ascending ones being distributed to the temporal, and the descending to the four other muscles of the inter-maxillary region, viz. the two pterygoids, the masseter and buccinator. The branches of the pterygo- maxillary portion of the artery are, 11. The superior dental artery. 12. The infra-or- bital artery. 13. The posterior palatine. 14. The spheno-palatine or nasal. 15. The pterygo-palatine. 16. The Vidian. * The remarkable bend which the third portion ofthe artery makes as it turns inwards to enter the pterygo-maxillary fossa. 25 T 290 INTERNAL MAXILLARY ARTERY. while the other escapes with the nerve at the mental foramen, and anasto- moses with the inferior labial and submental branch of the facial. It sup- plies the teeth of the lower jaw7, sending small branches along the canals in their roots. The Arteria meningea media ascends behind the temporo-maxillary ar- ticulation to the foramen spinosum in the spinous process of the sphenoid bone, and entering the cranium, divides into an anterior and a posterior branch. The anterior branch crosses the great ala of the sphenoid to the groove or canal in the anterior inferior angle of the parietal bone, and di- vides into branches, which ramify upon the external surface of the dura mater, and anastomose with corresponding branches from the opposite side. The posterior branch crosses the squamous portion of the temporal oone, to the posterior part ofthe dura mater and cranium. The branches of the arteria meningea media are distributed chiefly to the bones of the skull; in the middle fossa this artery sends a small branch through the hiatus Fallopii to the facial nerve. The Meningea parva is a small branch which ascends to the foramen ovale, and passes into the skull to be distributed to the Casserian ganglion and dura mater. It gives off a twig to the nasal fossae and soft palate. The Muscular branches are distributed, as their names imply, to the five muscles of the maxillary region; the temporal branches (temporales pro- fun dae) are two in number. The Superior dental artery is given off from the internal maxillary, just as that vessel is about to make its turn inwards to reach the spheno-max- illary fossa. It descends upon the tuberosity of the superior maxillary bone, and sends its branches through several small foramina to supply the posterior teeth of the upper jaw7, and the antrum. The terminal branches are continued forwards upon the alveolar process, to be distributed to the gums and to the sockets of the teeth. The Infra-orbital would appear, from its size, to be the proper con- tinuation of the artery. It runs along the infra-orbital canal with the superior maxillary nerve, sending branches into the orbit and downwards, through canals in the bone, to supply the mucous lining of the antrum and the teeth of the upper jaw7, and it emerges on the face at the infra- orbital foramen. The branch which supplies the incisor teeth is the ante- rior dental artery; on the face the infra-orbital inosculates with the facial and transverse facial arteries. The Pterygo-palatine is a small branch which passes through the pterygo-palatine canal, and supplies the upper part of the pharynx and Eustachian tube. The Spheno-palatine, or nasal, enters the superior meatus of the nose through the spheno-palatine foramen, in company with the nasal branches of Meckel's ganglion, and divides into two branches; one of which is distributed in the mucous membrane of the septum, while the other sup- plies the mucous membrane of the lateral wall of the nares, together with the sphenoid and ethmoid cells. The Posterior palatine artery descends along the posterior palatine canal, in company with the posterior palatine branches of Meckel's gan- glion, to the posterior palatine foramen ; it then curves forward, lying in a groove upon the bone, and is distributed to the palate. While in the posterior palatine canal it sends a branch backwards, through the siriall posterior palatine foramen, to supply the soft palate, and anteriorly it dis- INTERNAL carotid artery. 291 tributes a branch to the anterior palatine canal, which reaches the nares, and inosculates with the branches of the spheno-palatine artery. The Vidian branch passes backwards along the pterygoid canal, and is distributed to the sheath of the Vidian nerve, and to the Eustachian tube. INTERNAL CAROTID ARTERY. The internal carotid artery curves slightly outwards from the bifurcation of the common carotid, and then ascends nearly perpendicularly through the maxillo-pharyngeal space* to the carotid foramen in the petrous bone. It next passes inwards, along the carotid canal, forwards by the side of the sella turcica, and upwards by the anterior clinoid process, where it pierces the dura mater, and divides into three terminal branches. The course of this artery is remarkable for the number of angular curves which it forms; one or two of these flexures are sometimes seen in the cervical portion of the vessel, near the base of the skull; and by the side of the sella turcica it resembles the italic letter s, placed horizontally. Relations. — In consideration of its connexions, the artery is divisible into a cervical, petrous, cavernous, and cerebral portion. The Cervical portion is in relation posteriorly with the rectus anticus major, sympathetic nerve, pharyngeal and laryngeal nerves, which cross behind it, and near the carotid foramen with the glosso-pharyngeal, pneumogastric, and hypo- glossal nerves, and partially with the internal jugular vein. Internally it is in relation with the side of the pharynx, the tonsil, and the ascending pharyngeal artery. Externally with the internal jugular vein, glosso- pharyngeal, pneumogastric, and hypo-glossal nerves; and in front with the stylo-glossus, and stylo-pharyngeus muscle, glosso-pharyngeal nerve, and parotid gland. Plan of the Relations of the Cervical Portion of the Internal Carotid Artery. In Front. Parotid gland, Stylo-glossus muscle, Stylo-pharyngeus muscle, Glosso-pharyngeal nerve. Internally. Pharynx, Tonsil, Ascending pharyn- geal artery. Internal Carotid Artery. Externally. Jugular vein, Glosso-pharyngeal, Pneumogastric, Hypo-glossal nerve. Behind. Superior cervical ganglion, Pneumogastric nerve, Glosso-pharyngeal nerve, Pharyngeal nerve, Superior laryngeal nerve, Sympathetic nerve, Rectus anticus major. The Petrous portion is separated from the bony wall of the carotid canal by a lining of dura mater; it is in relation with the carotid plexus, and is covered in by the Casserian ganglion. * Far the boundaries of this space see page If 292 OPHTHALMIC ARTERY. The Cavernous portion is situated in the inner wall of the cavernous sinus, and is in relation by its outer side with the lining membrane of the sinus, the sixth nerve, and the ascending branches of the carotid plexus. The third, fourth, and ophthalmic nerves are placed in the outer wall of the cavernous sinus, and are separated from the artery by the lining mem- brane of the sinus. The Cerebral portion of the artery is enclosed in a sheath of the arach- noid, and is in relation with the optic nerve. At its point of division it is situated in the fissure of Sylvius. Branches.—The cervical portion of the internal carotid gives off no branches: from the other portions are derived the following:— Tympanic, Anterior meningeal, Ophthalmic, Anterior cerebral, Middle cerebral, Posterior communicating, Choroidean. The Tympanic is a small branch which enters the tympanum through a minute foramen in the carotid canal. The Anterior meningeal is distributed to the dura mater and Casserian ganglion. The Ophthalmic artery arises from the cerebral portion of the internal carotid, and enters the orbit through the foramen opticum, immediately to the outer side of the optic nerve. It then crosses the optic nerve to the inner wall of the orbit, and runs along 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 the ophthalmic artery may be arranged into two groups: first, those distributed to the orbit and surrounding parts; and, secondly, those which supply the muscles and globe of the eye. They are— First Group. Second Group. Lachrymal, Muscular, Supra-orbital, Anterior ciliary, Posterior ethmoidal, Ciliary short and long, Anterior ethmoidal, Centralis retina?. Palpebral, Frontal, Nasal. The Lachrymal is the first branch of the ophthalmic artery, and is usu ally given off immediately before that artery enters the optic foramen, ll follows the course of the lachrymal nerve, along the upper border of the external rectus muscle, and is distributed to the lachrymal gland. The small branches which escape from the gland supply the conjunctiva and upper eyelid. The lachrymal artery gives off a malar branch which passes through the malar bone into the temporal fossa and inosculates with the deep temporal arteries, while some of its branches become subcutaneous on the cheek, and anastomose with the transverse facial. OPHTHALMIC ARTERY. 293 x'he Supra-orbital artery follows the course of the frontal nerve, resting on the levator palpebral muscle; it passes through the supra-orbital fora- men, and divides into a superficial and deep branch, which are distributed to the muscles and integument of the forehead, and to the pericranium. At the supra-orbital foramen it sends a branch inwards to the diploe. The Ethmoidal arteries, posterior and anterior, pass through the eth- moidal foramina, and are distributed to the falx cerebri and to the ethmoidal cells and nasal fossae. The latter accompanies the nasal nerve. The Palpebral arteries, superior and inferior, are given off from the ophthalmic, near the inner angle of the orbit; they encircle the eyelids, forming a superior and an inferior arch near the borders of the lids, between the orbicularis palpebrarum and tarsal cartilage. At the outer angle of the eyelids the superior palpebral inosculates with the orbitar branch of the temporal artery. The inferior palpebral artery sends a branch to the nasal duct. The Frontal artery, one of the terminal branches of the ophthalmic, emerges from the orbit at its inner angle, and ascends along the middle of the forehead. It is distributed to the integument, muscles, and peri- cranium. The Nasal artery, the other terminal branch of the ophthalmic, passes out of the orbit above the tendo oculi, and divides into two branches ; one of which inosculates with the angular artery, wdiile the other, the dorsalis nasi, runs along the ridge ofthe nose, and is distributed to the integument of that organ. The nasal artery sends a small branch to the lachrymal sac. The Muscular branches, usually two in number, superior and inferior, supply the muscles of the orbit; and upon the anterior aspect of the globe of the eye give off the anterior ciliary arteries, which pierce the sclerotic near its margin of connection with the cornea, and are distributed to the iris. It is the congestion of these vessels that gives rise to the vascular zone around the cornea in iritis. The Ciliary arteries are divisible into three groups, short, long, and anterior. The Short ciliary are very numerous; they pierce the sclerotic around the entrance of the optic nerve, and supply the choroid coat and ciliary processes. The long ciliary, two in number, pierce the sclerotic on oppo- site sides of the globe of the eye, and pass forwards betw-een it and the choroid to the iris. They form an arterial circle around the circumference of the iris by inosculating with each other, and from this circle branches are given off which ramify in the substance of the iris, and form a second circle around the pupil. The anterior ciliary are branches of the muscular arteries; they terminate in the great arterial circle of the iris. The Centralis retina artery pierces the optic nerve obliquely, and passes forwards in the centre of its cylinder to the retina, where it divides into branches, which ramify in the inner layer of that membrane. It supplies the retina, hyaloid membrane, and zonula ciliaris; and, by means of a branch sent forwards through the centre of the vitreous humour in a tubular sheath of the hyaloid membrane, the capsule of the lens. The Anterior cerebral artery passes forwards in the great longitudina. fissure between the two hemispheres of the brain; then curves backwards along the corpus callosum to its posterior extremity. It gives branches 25* 294 SUBCLAVIAN ARTERY. to the olfactory and optic nerves, to the under surface ofthe anterior lobes, the third ventricle, the corpus callosum, and the inner surface of the hemispheres. The two anterior cerebral arteries are connected soon after their origin by a short anastomosing trunk, the anterior communicating artery. The Middle cerebral artery, larger than the preceding, passes outwards along the fissure of Sylvius, and divides into three principal branches, which supply the anterior and middle lobes of the brain, and the island of Reil. Near its origin it gives off the numerous small branches which enter the substantia perforata, to be distributed to the corpus striatum. The Posterior Communicating artery, very variable in size, sometimes double, and sometimes altogether absent, passes backwards and inoscu- lates with the posterior cerebral, a branch of the basilar artery. Occa- sionally it is so large as to take the place of the posterior cerebral artery. The Choroidean is a small branch which is given off from the internal carotid, near the origin of the posterior communicating artery, and passes beneath the edge of the middle lobe of the brain to enter the descending cornu of the lateral ventricle. It is distributed to the choroid plexus, and to the walls of the middle cornu. SUBCLAVIAN ARTERY. The Subclavian artery, on the right side, arises from the arteria inno- minata, opposite the sterno-clavicular articulation, and on the left, from the arch of the aorta. The right is consequently snorter than the left, and is situated nearer the anterior wall of the chest; it is also somewhat greater in diameter, from being a branch of a branch, in place of a division from the main trunk. The course of the subclavian artery is divisible, for the sake of precision and surgical observation, into three portions. The first portion of the right and left arteries differs in its course and relations in correspondence with the dissimilarity of origin of the respective arteries. The other two portions are precisely alike on both sides. The first portion, on the right side, ascends obliquely outwards to the inner border of the scalenus anticus. On the left side it ascends perpen- dicularly to the inner border of that muscle. The second portion curves outwards behind the scalenus anticus ; and the third portion passes down- wards and outwards beneath the clavicle, to the lower border of the first rib, where it becomes the axillary artery. Relations.—The first portion, on the right side, is in relation, m front, with the internal jugular and subclavian vein at their point of junction, and is crossed by the pneumogastric nerve, cardiac nerves, and phrenic nerve. Behind and beneath it is invested by the pleura, is crossed by the right recurrent laryngeal nerve and vertebral vein, and is in relation with the transverse process of the seventh cervical vertebra. The first portion on the left side is in relation in front with the pleura, the vena innomi- nata, the pneumogastric and phrenic nerves (which lie parallel to it), and the left carotid artery. To its inner side is the oesophagus; to its outer side the pleura; and behind, the thoracic duct, longus colli, and vertebral column. SUBCLAVIAN ARTERY—RELATIONS. 295 Plan ofthe Relations ofthe First Portion ofthe Right Subclavian Artery In Front. Internal jugular vein, Subclavian vein, Pneumogastric nerve, Cardiac nerves, Phrenic nerve. Right Subclavian Artery. Behind and Beneath. Pleura, Recurrent laryngeal nerve, Vertebral vein, Transverse process of the 7th cervical vertebra. Plan of the Relations of the First Portion of the Left Subclavian Artery. In Front. Pleura, Vena innominata, Pneumogastric nerve, Phrenic nerve, Left carotid artery. Inner Side. CEsophagus. Left Subclavian Artery. Outer Side. Pleura. Behind. Thoracic duct, Longus colli, Vertebral column. The Second portion is situated between the two scaleni, and is supported by the margin of the first rib. The scalenus anticus separates it from the subclavian vein and phrenic nerve. Behind, it is in relation with the brachial plexus. The Third portion is in relation, in front, with the subclavian vein and subclavius muscle ; behind, with the brachial plexus and scalenus posti- cus ; below with the first rib; and above with the supra-scapular artery and platysma. Plan of the Relations of the Third Portion of the Subclavian Artery. Above. Supra-scapular artery, Platysma myoides. In Front. Subclavian vein, Subclavius. Subclavian artery, Third portion. Behind. Brachial plexus, Scalenus posticus. Below. First rib. 296 VERTEBRAL AND BASILAR ARTERIES. Branches.—The greater part of the branches of the subclavian are given off from the artery before it arrives at the margin of the first rib. The profunda cervicis and superior intercostal frequently encroach upon the second portion, and not unfrequently a branch or branches may be found proceeding from the third portion. The primary branches are five in number, the first three being ascend- ing, and the remaining two descending: they are the— Vertebral, Thyroid axis, Profunda cervicis, Superior intercostal, Internal mammary. Inferior thyroid, Supra-scapular, Posterior scapular, Superficial cervicis. Fig. 148 * The Vertebral artery is the first and the largest of the branches of the subclavian artery; it ascends through the foramina in the transverse processes of all the cervical vertebrae, ex- cepting the last; then winds backwards around the articulating process of the atlas; and, piercing the dura mater, enters the skull through the foramen magnum. The two arte- ries unite at the low7er border of the pons Varolii, to form the basilar artery. In the foramina of the transverse processes of the vertebrae the artery lies in front of the cer- vical nerves. Dr. John Davyf has observed that, when the vertebral arteries differ in size, the left is generally the larger: thus in ninety-eight cases he found the left vertebral the larger twenty-six times, and the right only eight. In the same number of cases he found a small band stretching across the cylinder of the basilar artery, near the junction of the two vertebral arteries, seventeen times, and in a few instances a small communicating trunk between the two vertebral arteries previously to their union. I have several times seen this communicating branch, and have a preparation now before me in which it is exhibited. The Basilar artery, so named from its position at the base of the brain, runs forwards to the anterior border of the pons Varolii, where it divides into four ultimate branches, two to either side. Branches. — The branches of the vertebral and basilar arteries are the following:— * The branches of the right subclavian artery. 1. The arteria innominata. 2. The right carotid. 3. The first portion of the subclavian artery. 4. The second portion. 5. The third portion. 6. The vertebral artery. 7. The inferior thyroid. 8. The thyroid axis. 9. The superficialis cervicis. 10. The profunda cervicis. 11. The posterior scapular or transversalis colli. 12. The supra-scapular. 13. The internal mammary artery. 14. The superior intercostal. ■j- Edinburgh Medical and Surgical Journal, 1839. BASILAR ARTERY. 297 Vertebral, Lateral spinal, Posterior meningeal, Anterior spinal, Posterior spinal, Inferior cerebellar. {Transverse, Superior cerebellar, Posterior cerebral. The Lateral spinal branches enter the intervertebral foramina, and are distributed to the spinal cord and to its membranes. Where the vertebral artery curves around the articular process of the atlas, it gives off several muscular branches. The Posterior meningeal are one or tw7o small branches which enter the cranium through the foramen magnum, to be distributed to the dura mater of the cerebellar fossae, and to the falx cerebelli. One branch, described by Soemmering, passes into the cranium along the first cervical nerve. The Anterior spinal is a small branch which unites with its fellow of the opposite side, on the front of the medulla oblongata. The artery formed by the union of these two vessels, descends along the anterior aspect of the spinal cord, to which it distributes branches. The Posterior spinal winds around the medulla oblongata to the poste- rior aspect of the cord, and descends on either side, communicating very freely with the spinal branches of the intercostal and lumbar arteries. Near its commencement it sends a branch upwards to the four ventricle. The Inferior cerebellar arteries wind around the upper part of the me- dulla oblongata to the under surface of the cerebellum, to which they are distributed. They pass between the filaments of origin of the hypo- glossal nerve in their course, and anastomose with the superior cerebellar arteries. The Transverse branches of the basilar artery supply the pons Varolii, and adjacent parts of the brain. One of these branches, larger than the rest, passes along the crus cerebelli, to be distributed to the anterior bor- der of the cerebellum. This may be called the middle cerebellar artery. The Superior cerebellar arteries, two of the terminal branches of the basilar, wind around the crus cerebri on each side, lying in relation with the fourth nerve, and are distributed to the upper surface of the cerebellum, inosculating with the inferior cerebellar. This artery gives off a small branch, which accompanies the seventh pair of nerves into the meatus auditorius internus. The Posterior cerebral arteries, the other two terminal branches of the basilar, wind around the crus cerebri at each side, and are distributed to the posterior lobes of the cerebrum. They are separated from the supe- rior cerebellar arteries, near their origin, by the third pair of nerves, and are in close relation with the fourth pair, in their course around the crura cerebri. Anteriorly, near their origin, they give off a tuft of small vessels, which enter the locus perforatus, and they receive the posterior communi- cating arteries from the internal carotid. They also send a branch to the velum interpositum and plexus choroides. The communications established between the anterior cerebral arteries in front and the internal carotids and posterior cerebral arteries behind, by the communicating arteries, constitute the circle of Willis. This 298 SUPRA-SCAPULAR ARTERY. remarkable communication at the base of the brain is formed by the ante- rior communicating branch, anterior cerebrals, and internal carotid arteries, Fig. 149.* in front, and by the posterior communicating, posterior cerebrals, and basilar artery, behind. The Thyroid axis is a short trunk, which divides almost immediately after its origin into four branches, some of which are occasionally branches of the subclavian artery itself. The Inferior thyroid artery ascends obliquely in a serpentine course behind the sheath of the carotid vessels, to the inferior part of the thyroid gland, to which it is distributed; it sends branches also to the trachea, lower part of the larynx, and oesophagus. It is in relation with the middle cervical ganglion of the sympathetic, which lies in front of it. The Supra-scapular artery (transversalis humeri) passes obliquely outwards behind the clavicle, and over the ligament of the supra-scapulai notch, to the supra-spinatus fossa. It crosses in its course the scalenus , anticus muscle, phrenic nerve, and subclavian artery, is distributed to the * The circle of Willis. The arteries have references only on one side, on account of their symmetrical distribution. 1. The vertebral arteries. 2. The two anterior spinal branches uniting to form a single vessel. 3. One of the posterior spinal arteries. 4. The posterior meningeal. 5. The inferior cerebellar. 6. The basilar artery giving off its transverse branches to either side. 7. The superior cerebellar artery. 8. The posterior cerebral. 9. The posterior communicating branch of the internal carotid. 10. The in- ternal carotid artery, showing the curvatures it makes within the skull. 11. The oph- thalmic artery divided across. 12. The middle cerebral artery. 13. The anterior cere- bral arteries connected by, 14. The anterior communicating artery. INTERNAL MAMMARY ARTERY. 299 muscles on the dorsum of the scapula, and inosculates with the posterior scapular, and beneath the acromion process with the dorsal branch of the subscapular artery. At the supra-scapular notch it sends a large branch to the trapezius muscle. The supra-scapular artery is not unfrequently a branch of the subclavian. The Posterior scapular artery (transversalis colli) passes trans- versely across the subclavian triangle at the root of the neck, to the supe- rior angle of the scapula. It then descends along the posterior border of that bone to its inferior angle, where it inosculates with the subscapular artery, a branch ofthe axillary. In its course across the neck it passes in front of the scalenus anticus, and across the brachial plexus; in the rest of its course it is covered in by the trapezius, levator anguli scapulae, rhomboideus minor, and rhomboideus major muscles. Sometimes it passes behind the scalenus anticus, and between the nerves, which constitute the brachial plexus. This artery, which is very irregular in its origin, pro- ceeds more frequently from the third portion of the subclavian artery than from the first. The posterior scapular gives branches to the neck, and opposite the angle of the scapula inosculates with the profunda cervicis. It supplies the muscles along the posterior border of the scapula, and establishes an important anastomotic communication between the branches of the exter- nal carotid, subclavian, and axillary arteries. The Superficialis cervicis artery (cervicalis anterior) is a small vessel, which ascends upon the anterior tubercles of the transverse pro- cesses of the cervical vertebrae, lying in the groove between the scalenus anticus and rectus anticus major. It is distributed to the deep muscles and glands of the neck, and sends branches through the intervertebral foramina to supply the spinal cord and its membranes. The Profunda cervicis (cervicalis posterior) passes backwards between the transverse processes of the seventh cervical and first dorsal vertebrae, and then ascends the back part of the neck, between the complexus and semi-spinalis colli muscles. It inosculates above with the princeps cervicis of the occipital artery, and below, by a descending branch, with the pos- terior scapular. The Superior intercostal artery descends behind the pleura upon the necks of the first two ribs, and inosculates with the first aortic inter- costal. It gives off two branches which supply the first two .intercostal spaces. The Internal mammary artery descends by the side of the sternum, resting against the costal cartilages, to the diaphragm; it then pierces the anterior fibres ofthe diaphragm, and enters the sheath ofthe rectus, where it inosculates with the epigastric artery, a branch of the external iliac. In the upper part of its course it is crossed by the phrenic nerve, and lower down lies between the triangularis sterni and the internal intercostal muscles. The Branches of the internal mammary are,— Anterior intercostal, Mediastinal, Mammary, Pericardiac, Comes neivi phrenici, Musculo-phrenic. 300 AXILLARY ARTERY. The Anterior intercostals supply the intercostal muscles of the front of the chest, and inosculate with the aortic intercostal arteries. Each of the first three anterior intercostals gives off a large branch to the mammary gland, which anastomoses freely with the thoracic branches of the axillary artery; the corresponding branches from the remaining intercostals supply the integument and pectoralis major muscle. There are usually two an- terior intercostal arteries in each space. The Comes nervi phrenici is a long and slender branch which accom- panies the phrenic nerve. The mediastinal and pericardiac branches are small vessels distributed to the anterior mediastinum, the thymus gland, and pericardium. The Musculo-phrenic artery winds along the attachment of the diaphragm to the ribs, supplying that muscle, and sending branches to the inferior intercostal spaces. " The mammary arteries," says Dr. Harrison, " are remarkable for the number of their inosculations, and for the distant parts ofthe arterial system which they serve to connect. They anastomose with each other, and their inosculations, with the thoracic aorta, encircle the thorax. On the parietes of this cavity their branches connect the axillary and subclavian arteries; on the diaphragm they form a link in the chain of inosculations between the subclavian artery and abdominal aorta, and in the parietes of the abdomen they form an anastomosis most remarkable for the distance between those vessels which it serves to connect; namely, the arteries ofthe superior and inferior extremities." Varieties of the subclavian Arteries.—Varieties in these arteries are rare; that which most frequently occurs is the origin of the right subclavian, from the left extremity of the arch of the aorta, below the left subclavian artery. The vessel, in this case, curves behind the oesophagus and right carotid artery, and sometimes between the oesophagus and trachea, to the upper border of the first rib on the right side of the chest, where it assumes its ordinary course. In a case* of subclavian aneurism on the right side, above the clavicle, which happened during the summer of 1839, Mr. Lis- ton proceeded to perform the operation of tying the carotid and subclavian arteries at their point of division from the innominata. Upon reaching the spot where the bifurcation should have existed, he found that there was no subclavian artery. With the admirable self-possession which dis- tinguishes this eminent surgeon in all cases of emergency, he continued his dissection more deeply, towards the vertebral column, and succeeded in securing the artery. It was ascertained after death, that the arteria innominata was extremely short, and that the subclavian was given off within the chest from the posterior aspect of its trunk, and pursued a deep course to the upper margin of the first rib. In a preparation which was shown to me in Heidelberg some years since by Professor Tiedemann, the right subclavian artery arose from the thoracic aorta, as low down as the fourth dorsal vertebra, and ascended from that point to the border of the first rib. Varieties in the branches of the subclavian are not unfre- quent; the most interesting is the origin of the left vertebral from the arch of the aorta, of which I possess several preparations. AXILLARY ARTERY. The axillary artery forms a gentle curve through the middle of the * This case is recorded in the Lancet, vol. i. 1839-40, pp. 37 and 419. AXILLARY ARTERY—BRANCHES. 301 axillary space from the lower border of the first rib to the lower border of the latissimus dorsi, where it becomes the brachial. Relations.—After emerging from beneath the margin of the costo-cora- coid membrane, it is in relation with the axillary vein, which lies at first to the inner side, and then in front of the artery. Near the middle of the axilla it is embraced by the two heads of the median nerve, and is covered in by the pectoral muscles. Upon the inner or thoracic side it is in rela- tion, first, with the first intercostal muscle; it next rests upon the first serration of the serratus magnus; and is then separated from the chest by the brachial plexus of nerves. By its outer or humeral si'le it is at first separated from the brachial plexus by a triangular interval of areolar tis- sue ; it next rests against the tendon of the subscapularis muscle ; and thirdly, upon the coraco-brachialis muscle. The relations of the axillary artery may be thus arranged:— In Front. Inner or Thoracic Side. Outer or Humeral Side. First intercostal muscle, Plexus of nerves, Tendon of sub- Pectoralis major, Pectoralis minor, Pectoralis major. First serration of serra- tus magnus, Plexus of nerves. scapularis, Coraco-brachialis. Branches.—The branches of the Axillary artery are seven in number:— Thoracica acromialis, Fig. 150.* Superior thoracic, Inferior thoracic, Thoracica axillaris, Subscapular, Circumflex anterior, Circumflex posterior. The thoracica acromialis and superior thoracic are found in the triangular space above the pectoralis minor. The inferior thoracic and thoracica axillaris, below the pectoralis minor. And the three remaining branches below the lower border of the sub- scapularis. The Thoracica acromialis is a short trunk which ascends to the space above the pec- toralis minor muscle, and divides into three branches, thoracic, which is distributed to the pectoral muscles and mammary gland ; acromial, which passes outwards to the acromion, and inosculates with branches of the supra-scapular artery; and descending, which follows the interspace between the deltoid and pectoralis major muscles, and is in relation with the cephalic vein. * The axillary and brachial artery, with their branches. 1. The deltoid muscle. 2. The biceps. 3. The tendinous process given off from the tendon of the biceps, to the deep fascia of the fore-arm. It is this process which separates the median basilic vein from the brachial artery. 4. The outer border ofthe brachialis anticus muscle. 5. The supinator longus. 6. The coraco-brachialis. 7. The middle portion of the triceps 26 302 VARIETIES OF THE AXILLARY ARTERY. The Superior thoracic (short) frequently arises by a common trunk with the preceding; it runs along the upper border of" the pectoralis minor, and is distributed to the pectoral muscles and mammary gland, inosculat- ing with the intercostal and mammary arteries. The Inferior thoracic (long external mammary) descends along the lower border of the pectoralis minor to the side of the chest. It is distri- buted to the pectoralis major and minor, serratus magnus, and subscapu- laris muscle, to the axillary glands and mammary gland; inosculating with the superior thoracic, intercostal, and mammary arteries. The Thoracica axillaris is a small branch distributed to the plexus of nerves and glands in the axilla. It is frequently derived from one of the other thoracic branches. The Subscapular artery, the largest of the branches of the axillary, runs along the lower border of the subscapularis muscle, to the inferior angle of the scapula, where it inosculates with the posterior scapular, a branch of the subclavian. It supplies, in its course, the muscles on the under surface and inferior border of the scapula, and the side of the chest. At about an inch and a half from the axillary, it gives off a large branch, the dorsalis scapulce, which passes backwards through the triangular space bounded by the teres minor, teres major, and scapular head of the triceps, and beneath the infra-spinatus to the dorsum of the scapula, where it is distributed, inosculating with the supra-scapular and posterior scapular arteries. The Circumflex arteries wind around the neck of the humerus. The anterior,very small, passes beneath the coraco-brachialis and short head of the biceps, and sends a branch upwards along the bicipital groove to supply the shoulder joint. The Posterior circumflex, of larger size, passes backwards through the quadrangular space bounded by the teres minor and major, the scapular head of the triceps and the humerus, and is distributed to the deltoid muscle and joint. Sometimes this artery is a branch of the superior pro- funda of the brachial. It then ascends behind the tendon of the teres major, and is distributed to the deltoid without passing through the quad- rangular space. The posterior circumflex artery sends branches to the shoulder joint. Varieties of the Axillary artery.—The most frequent peculiarity of this kind is the division of the vessel into tw7o trunks of equal size: a muscular trunk, which gives off some of the ordinary axillary branches and supplies the upper arm, and a continued trunk, which represents the brachial ar- tery. The next most frequent variety is the high division of the ulnai which passes down the arm by the side of the brachial artery, and superfi- cially to the muscles proceeding from the inner condyle, to its ordinary distribution in the hand. In this course it lies immediately beneath the muscle. 8. Its inner head. 9. The axillary artery. 10. The brachial artery;—a dark line marks the limit between these two vessels. 11. The thoracica acromialis artery dividing into its three branches; the number rests upon the coracoid process. 12. The superior and inferior thoracic arteries. 13. The serratus magnus muscle. 14. The subscapular artery. The posterior circumflex and thoracica axillaris branches are seen in the figure between the inferior thoracic and subscapular. The anterior circumflex is observed, between the two heads of the biceps, crossing the neck of the humerus. 15. The superior profunda artery. 16. The inferior profunda. 17. The anastomotica magna inosculating inferiorly with the anterior ulnar recurrent. 18. The termination of the superior profunda, inosculating with the radial recurrent in the interspace be- tween the brachialis anticus and supinator longus. BRACHIAL ARTERY. 303 deep fascia of the fore-arm, and may be seen and felt pulsating beneath the integument. The high division of the radial from the axillary is rare. In one instance, I saw the axillary artery divide into three branches of nearly equal size which passed together down the arm, and at the bend of the elbow resolved themselves into radial, ulnar, and interosseous. But the most interesting variety, both in a physiological and surgical sense, is that described by Dr. Jones Quain, in his " Elements of Anatomy." " I found in the dissecting-room, a few- years ago, a variety not hitherto no- ticed ; it was at first taken for the ordinary high division of the ulnar artery. The two vessels descended from the point of division at the bor- der of the axilla, and lay parallel with one another in their course through the arm; but instead of diverging, as is usual, at the bend of the elbow, they converged, and united so as to form a short trunk which soon divided again into the radial and ulnar arteries in the regular way." In a subject, dissected by myself, this variety existed in both arms; and I have seen several instances of a similar kind. BRACHIAL ARTERY. The Brachial artery passes down the inner side of the arm, from the lower border of the latissimus dorsi to the bend of the elbow, where it di- vides into the radial and ulnar arteries. Relations.—In its course downwards, it rests upon the coraco-brachialis muscle, internal head of the triceps, brachialis anticus, and the tendon of the biceps. To its inner side is the ulnar nerve; to the outer side, the coraco-brachialis and biceps muscles; in front it has the basilic vein, and is crossed by the median nerve. Its relations, within its sheath, are the venae comites. , Plan of the Relations of the Brachial Artery. In Front. Basilic vein, Deep fascia, Median nerve. Inner Side. Ulnar nerve. Brachial artery. Outer Side. Coraco-brachialis, Biceps. Behind. Short head of triceps, Coraco-brachialis, Brachialis anticus, Tendon of biceps. The branches of the brachial artery are, the— Superior profunda, Inferior profunda, Anastomotica magna, Muscular. The Superior profunda arises opposite the lower border of the latissimus dorsi and winds around the humerus, between the triceps and the bone, to the space between the brachialis anticus and supinator longus, where it 301 RADIAL ARTERY. Fig. 151* inosculates with the radial recurrent branch. It accompanies the musculo-spiral nerve. In its course it gives off the posterior articular artery, which descends to the elbow joint, and a more superficial branch which inosculates with the in- terosseous articular artery. The Inferior profunda arises from about the middle of the brachial artery, and descends to the space between the inner condyle and olecra- non in company with the ulnar nerve, where it inosculates with the posterior ulnar recurrent. The Anastomotica magna is given off nearly at right angles from the brachial, at about two inches above the joint. It passes directly inwards, and divides into two branches w7hich inosculate with the anterior and posterior ulnar recurrent arteries and with the inferior profunda. The Muscular branches are distributed to the muscles in the course of the artery, viz. to the coraco-brachialis, biceps, deltoid, brachialis an- ticus and triceps. Varieties of the Brachial Artery.—The most frequent peculiarity in the distribution of branches from this artery is the high division of the radial, which arises generally from about the upper third of the brachial artery, and descends to its normal position at the bend of the elbow. The ulnar artery »sometimes arises from the brachial at about two inches above the elbow, and pursues either a superficial or deep course to the wrist; and, in more than one instance, I have seen the interosseous artery arise from the brachial a little above the bend ofthe elbow. The two profunda arteries occasionally arise by a common trunk, or there may be two superior profundae. RADIAL ARTERY. The Radial artery, one of the divisions of the brachial, appears, from its direction, to be the continuation of that trunk. It runs along the radial side of the fore-arm, from the bend of the elbow to the wrist; it there turns around the base of the thumb, beneath its extensor tendons, and * The arteries of the fore-arm. 1. The lower part of the biceps muscle. 2. The inner condyle of the humerus with the humeral origin of the pronator radii teres and flexor carpi radialis divided across. 3. The deep portion of the pronator radii teres. 4. The supinator longus muscle. 5. The flexor longus pollicis. 6. The pronator quadratus. 7. The flexor profundus digitorum. 8. The flexor carpi ulnaris. 9. The annular ligament with the tendons passing beneath it into the palm of the hand ; the figure is placed on the tendon of the palmaris longus muscle, divided close to its insertion. 10. The brachial artery. 11. The anastomotica magna inosculating superiorly with the inferior profunda, and inferiorly with the anterior ulna recurrent. 12. The radial artery. 13. The radial recurrent artery inosculating with the termination of the superior profunda. 14. The superficialis vols. 15. The ulnar artery. 16. Its superficial palmar arch giving off di- gital branches to three fingers and a half. 17. The magna pollicis and radialis arteries. 18. The posterior ulnar recurrent. 19. The anterior interosseous artery. 20. The poste- rior interosseous, as it is passing through the interosseous membrane. RADIAL ARTERY. 305 passes between the two heads of the first dorsal interosseous muscle, into the palm of the hand. It then crosses the metacarpal bones to the ulnar side ot the hand, forming the deep palmar arch, and terminates by inoscu- lating with the superficial palmar arch. In the upper half of its course, the radial artery is situated between the supinator longus muscle, by which it is overlapped superiorly, and the pronator radii teres; in the lower half, between the tendons of the supina- tor longus and flexor carpi radialis. It rests in its course downwards, upon the supinator brevis, pronator radii teres, radial origin of the flexor sublimis, flexor longus pollicis, and pronator quadratus; and is covered in by the integument and fasciae. At the wrist it is situated in contact with the dorsal carpal ligaments and beneath the extensor tendons of the thumb; and, in the palm of the hand, beneath the flexor tendons. It is accompanied by venae comites throughout its course, and by its middle third is in close relation with the radial nerve. Plan of the Relations of the Radial Artery in the Fore-arm. In Front. Deep fascia, Supinator longus. Inner Side. Pronator radii teres, Flexor carpi radialis. Radial artery. Outer side. Supinator longus, Radial nerve (middle third of its course). Behind. Supinator brevis, Pronator radii teres, Flexor sublimis digitorum, Flexor longus pollicis. Pronator quadratus, Wrist joint. The Branches of the radial artery may be arranged into three groups, corresponding with the three regions, the fore-arm, the wrist, and the hand; they are— Fore-arm, Wrist, Hand, ( Recurrent radial, I Muscular. f Superficialis volae, | Carpalis anterior, < Carpalis posterior, Metacarpalis, Dorsales pollicis. Princeps pollicis, Radialis indicis, Interosseae, Perforantes. The Recurrent branch is given off immediately below the elbow; it as- cends in the space between the supinator longus and brachialis anticus to supply the joint, and inosculates with the terminal branches ofthe superior profunda. This vessel gives off numerous muscular branches. The Muscular branches are distributed to the muscles on the radial side ofthe fore-arm. 26* u 306 ULNAR ARTERY. The Superficialis voice is given off from the radial artery while at the wrist. It passes between the fibres of the abductor pollicis muscle, and inosculates with the termination of the ulnar artery, completing the super- ficial palmar arch. This artery is very variable in size, being sometimes as large as the continuation of the radial, and at other times a mere mus- cular ramusculus, or entirely wanting; when of large size it supplies the palmar side ofthe thumb and the radial side ofthe index finger. The Carpal branches are intended for the supply of the wrist, the ante- rior carpal in front, and the posterior, the larger of the two, behind. The carpalis posterior crosses the carpus transversely to the ulnar border ofthe hand, where it inosculates with the posterior carpal branch of the ulnar artery. Superiorly it sends branches which inosculate with the termination of the anterior interosseous artery ; inferiorly it gives off posterior interos- seous branches, which anastomose with the perforating branches of the deep palmar arch, and then run forward upon the dorsal interossei mus- cles. The Metacarpal branch runs forward on the second dorsal interosseous muscle, and inosculates with the digital branch of the superficial palmar arch, which supplies the adjoining sides of the index and middle fingers. Sometimes it is of large size, and the true continuation of the radial ar- tery. The Dorsales pollicis are tw7o small branches which run along the sides ofthe dorsal aspect of the thumb. The Princeps pollicis descends along the border ofthe metacarpal bone, between the abductor indicis and adductor pollicis to the base of the first phalanx, where it divides into two branches, which are distributed to the two sides of the palmar aspect of the thumb. The Radialis indicis is also situated between the abductor indicis and the adductor pollicis, and runs along the radial side of the index finger, forming its collateral artery. This vessel is frequently a branch of the princeps pollicis. The Interosseae, three or four in number, are branches of the deep pal- mar arch; they pass forward upon the interossei muscles, and inosculate with the digital branches of the superficial arch, opposite the heads of the metacarpal bones. The Perforantes, three in number, pass directly backwards between the heads of the dorsal interossei muscles, and inosculate with the posterior interosseous arteries. ULNAR ARTERY. The Ulnar artery, the other division of the brachial artery, crosses the arm obliquely to the commencement of its middle third ; it then runs down the ulnar side of the fore-arm to the wrist, crosses the annular ligament, and forms the superficial palmar arch, which terminates by inosculating with the superficialis volae. Relations. — In the upper or oblique portion of its course, it lies upon the brachialis anticus and flexor profundus digitorum ; and is covered in by the superficial layer of muscles of the fore-arm and by the median nerve. In the second part of its course, it is placed upon the flexor profundus and pronator quadratus, lying between the flexor carpi ulnaris and flexor sub- limis digitorum. While crossing the annular ligament it is protected from injury by a strong tendinous arch, thrown over it from the pisiform bone; ULNAR ARTERY--BRANCHES. 307 and in the palm it rests upon the tendons of the flexor sublimis, beinc covered in by the palmaris brevis muscle and palmar fascia. It is accom- panied in its course by the venae comites, and is in relation with the ulnar nerve for the lower two-thirds of its extent. Plan ofthe Relations ofthe Ulnar Artery. In Front. Deep fascia, Superficial layer of muscles, Median nerve. In the Hand. Tendinous arch from the pisiform bone, Palmaris brevis muscle, Palmar fascia. Inner Side. Flexor carpi ulnaris, Ulnar nerve (lower two-thirds). Ulnar artery. Outer Side. Flexor sublimis digi- Behind. Brachialis anticus, Flexor profundus digitorum, Pronator quadratus. In the Hand. Annular ligament, Tendons ofthe flexor sublimis digitorum. The Branches of the ulnar artery may be arranged, like those of the radial, into three groups :— Fore-arm, Wrist, Hand, Anterior ulnar recurrent, Posterior ulnar recurrent, T . S Anterior interosseous, Interosseous, < r> f • • . ( .Posterior interosseous. Muscular. Carpalis anterior, Carpalis posterior. Diofitales. The Anterior ulnar recurrent arises immediately below the elbow, and ascends in front ofthe joint between the pronator radii teres and brachialis anticus, where it inosculates with the anastomotica magna and inferior profunda. The two recurrent arteries frequently arise by a common trunk. The Posterior ulnar recurrent, larger than the preceding, arises imme- diately below the elbow joint, and passes backw-ards beneath the origins ofthe superficial layer of muscles ; it then ascends between the two heads of the flexor carpi ulnaris, and beneath the ulnar nerve, and inosculates with the inferior profunda and anastomotica magna. The Common interosseous artery is a short trunk which arises from the ulnar, opposite the bicipital tuberosity of the radius. It divides into two branches the anterior and posterior interosseous arteries. 308 BRANCHES OF THE THORACIC AORTA. The Anterior interosseous passes down the fore-arm upon the interosse- ous membrane, between the flexor profundus digitorum and flexor longus pollicis, and behind the pronator quadratus. In the latter position it pierces the interosseous membrane, and descends to the back of the wrist, where it inosculates with the posterior carpal branches of the radial and ulnar. It is retained in connexion with the interosseous membrane by means of a thin aponeurotic arch. The anterior interosseous artery sends a branch to the median nerve, which it accompanies into the hand. The median artery is sometimes of large size, and occasionally takes the place of the superficial palmar arch. The Posterior interosseous artery passes backwards through an opening between the upper part of the interosseous membrane and the oblique ligament, and is distributed to the muscles on the posterior aspect of the fore-arm. It gives off a recurrent branch, wrhich returns upon the elbow between the anconeus, extensor carpi ulnaris and supinator brevis muscles, and anastomoses with the posterior terminal branches of the superior pro- funda. The Muscular branches supply the muscles situated along the ulnar border of the fore-arm. The Carpal branches, anterior and posterior, are distributed to the an- terior and posterior aspects of the wrist joint, where they inosculate with corresponding branches of the radial artery. The Digital branches are given off from the superficial palmar arch, and are four in number. The first and smallest is distributed to the ulnar side of the little finger. The other three are short trunks, which divide be- tween the heads of the metacarpal bones, and form the collateral branch of the radial side of the little finger, the collateral branches of the ring and middle fingers, and the collateral branch of the ulnar side of the index finger. The Superficial palmar arch receives the termination of the deep palmar arch from between the abductor minimi digiti and flexor brevis minJmi digiti near their origins, and terminates by inosculating with the superfi- cialis volae upon the ball ofthe thumb. The communication between the superficial and deep arch is generally described as the communicating branch of the ulnar artery. The mode of distribution of the arteries to the hand is subject to fre- quent variety. BRANCHES OF THE THORACIC AORTA. Bronchial, CEsophageal, Intercostal. The Bronchial arteries are four in number, and vary both in size and origin. They are distributed to the bronchial glands and tubes, and send branches to the oesophagus, pericardium, and left auricle of the heart. These are the nutritious vessels of the lungs. The CEsophageal arteries are numerous small branches; they arise from the anterior part of the aorta, are distributed to the oesophagus, and establish a chain of anastomoses along that tube : the superior inosculate with the bronchial arteries, and with oesophageal branches of the inferior BRANCHES OF THE ABDOMINAL AORTA. 309 thyroid arteries; and the inferior with similar branches of the phrenic and gastric arteries. The Intercostal, or posterior intercostal arteries, arise from the poste- rior part of the aorta; they are nine in number on each side, the two su- perior spaces being supplied by the superior intercostal artery, a branch of the subclavian. The right intercostals are longer than the left, on ac- count of the position of the aorta. They ascend somewhat obliquely from their origin, and cross the vertebral column behind the thoracic duct, vena azygos major, and sympathetic nerve, to the intercostal spaces, the left passing beneath the superior intercostal vein, the vena azygos minor and sympathetic. In the intercostal spaces, or rather, upon the external inter- costal muscles, each artery gives oil' a dorsal branch, which passes back between the transverse processes of the vertebrae, lying internally to the middle costo-transverse ligament, and divides into a spinal branch, which supplies the spinal cord and vertebra?, and a muscular branch which is distributed to the muscles and integument of the back. The artery then comes into relation with its vein and nerve, the former being above and the latter below, and divides into two branches which run along the bor- ders of contiguous ribs between the two planes of intercostal muscles, and anastomose with the anterior intercostal arteries, branches of the internal mammary. The branch corresponding with the lower border of each rib is the larger of the two. They are protected from pressure during the action of the intercostal muscles, by little tendinous arches thrown across them and attached by each extremity to the bone. BRANCHES OF THE ABDOMINAL AORTA. Phrenic, ( Gastric, Coeliac axis < Hepatic, ( Splenic. Superior mesenteric, Spermatic, Inferior mesenteric, Supra-renal, Renal, Lumbar, Sacra media. The Phrenic arteries are given off from the anterior part of the aorta as soon as that trunk has passed through the aortic opening. Passing obliquely outwards upon the under surface of the diaphragm, each artery divides into two branches, an internal branch, w7hich runs forwards, and inosculates with its fellow of the opposite side in front of the oesophageal opening; and an external branch, which proceeds outwards towards the great circumference of the muscle, and sends branches to the supra-renal capsules. The phrenic arteries inosculate with branches of the internal mammary, inferior intercostal, epigastric, oesophageal, gastric, hepatic, and supra-renal arteries. They are not unfrequently derived from the coeliac axis or from one of its divisions, and sometimes they give off the supra- renal arteries. 310 GASTRIC AND HEPATIC ARTERIES. The Cceliac axis (xoiXia, ventriculus) is the first single trunk given off from the abdominal aorta. It arises opposite the upper border of the first lumbar vertebra, is about half an FiS-152* inch in length, and divides into three large branches, gastric, he- patic, and splenic. Relations. — The trunk of the coeliac axis has in relation with it, in front, the lesser omentum ; on the right side the right semilunar ganglion and lob us Spigelii of the liver; on the left side the left semilunar ganglion and cardiac portion of the stomach; and below, the upper border of the pancreas and lesser curve of the stomach. It is completely surrounded by the solar plexus. The Gastric artery (coronaria ventriculi), the smallest ofthe three branches ofthe cceliac axis, ascends between the two layers ofthe lesser omentum to the cardiac orifice of the stomach, then runs along the lesser curvature to the pylorus, and inosculates with the pyloric branch of the hepatic. It is dis- tributed to the lower extremity of the oesophagus and lesser curve of the stomach, and anastomoses with the oesophageal arteries and vasa brevia of the splenic artery. The Hepatic artery curves forwards, and ascends along the right border of the lesser omentum to the liver, where it divides into two branches (right and left), which enter the transverse fissure, and are dis tributed along the portal canals to the right and left lobes, f It is in rela- tion, in the right border of the lesser omentum, with the ductus communis choledochus and portal vein, and is surrounded by the hepatic plexus of nerves and numerous lymphatics. There are sometimes two hepatic arteries, in wdiich case one is derived from the superior mesenteric artery. * The abdominal aorta with its branches. 1. The phrenic arteries. 2. The cceliac axis. 3. The gastric artery. 4. The hepatic artery, dividing into the right and left hepatic branches. 5. The splenic artery, passing outwards to the spleen. 6. The supra-renal artery ofthe right side. 7. The right renal artery, which is longer than the left, passing outwards to the right kidney. 8. The lumbar arteries. 9. The superior mesenteric artery. 10. The two spermatic arteries. 11. The inferior mesenteric artery. 12. The sacra media. 13. The common iliacs. 14. The internal iliac of the right side. 15. The external iliac artery. 16. The epigastric artery. 17. The circumflexa ilii artery. 18. The femoral artery. ■}• For the mode of distribution of the hepatic artery within the liver, see the " Minute Anatomy" of that organ in the Chapter on the Viscera. SPLENIC ARTERY. 311 The Branches of the hepatic artery are, the Pyloric, Gastro-duodenalis, j Gastro-epiploica dextra, ( rancreatico-duodenalis Cystic. The Pyloric branch, given off from the hepatic near the pylorus, is dis- tributed to the commencement of the duodenum and to the lesser curve of the stomach, where it inosculates with the gastric artery. The Gastro-duodenalis artery is a short but large trunk, which descends behind the pylorus, and divides into two branches, the gastro-epiploica dextra, and pancreatico-duodenalis. Previously to its division, it gives off some inferior pyloric branches to the small end of the stomach. The Gastro-epiploica dextra runs along the great curve of the stomach lying between the two layers of the great omentum, and inosculates at about its middle with the gastro-epiploica sinistra, a branch of the splenic artery. It supplies the great curve of the stomach and the great omentum; hence the derivation of its name. The Pancreatico-duodenalis curves along the fixed border of the duo- denum, partly concealed by the attachment of the pancreas, and is distri- buted to the pancreas and duodenum. It inosculates inferiorly with the first jejunal, and with the pancreatic branches of the superior mesenteric artery. The Cystic artery, generally a branch of the right hepatic, is of small size, and ramifies between the coats of the gall-bladder, previously to its distribution to the mucous membrane. The Splenic artery, the largest of the three branches of the coeliac axis, passes horizontally to the left along the upper border of the pancreas, and divides into five or six large branches, which enter the hilus of the spleen, and are distributed to its structure. In its course it is tortuous and serpentine, and frequently makes a complete turn upon itself. It lies in a narrow groove in the upper border of the pancreas, and is accom- panied by the splenic vein, and by the splenic plexus of nerves. The Branches of the splenic artery are the— Pancreaticae parvae, Pancreatica magna, Vasa brevia, Gastro-epiploica sinistra. The Pancreatica parva, are numerous small branches distributed to the pancreas, as the splenic border runs along it's upper border. One of these, larger than the rest, follows the course of the pancreatic duct, and is called pancreatica magna. The Vasa brevia are five or six branches of small size which pass from the extremity of the splenic artery and its terminal branches, between the layers of the gastro-splenic omentum, to the great end of the stomach, to which they are distributed, inosculating with branches ofthe gastric artery and gastro-epiploica sinistra. The Gastro-epiploica sinistra appears to be the continuation of the splenic artery; it passes forwards from left to right, along the great curve of the stomach, lying between the layers of the great omentum, and inos- 312 SUPERIOR MESENTERIC ARTERY. culates with the gastro-epiploica dextra. It is distributed to the gre curve of the stomach and to the great omentum. Fig. 153.* The Superior mesenteric artery, the second of the single trunks, and next in size to the cceliac axis, arises from the aorta immediately below that vessel, and behind the pancreas. It passes forwards between the pancreas and transverse duodenum, and descends within the layers of the mesentery, to the right iliac fossa, where it terminates, very much dimi- nished in size. It forms a curve in its course, the convexity being directed towards the left, and the concavity to the right. It is in relation near its commencement with the portal vein; and is accompanied by two veins, and the superior mesenteric plexus of nerves. The branches of the superior mesenteric artery are— Vasa intestini tenuis, Ileo-colica, Colica dextra, Colica media. The Vasa intestini tenuis arise from the convexity of the superior me- senteric artery. They vary from fifteen to tw7enty in number, and are dis- * The distribution ofthe branches ofthe cceliac axis. 1. The liver. 2. Its transverse fissure. 3. The gall-bladder. 4. The stomach. 5. The entrance of the oesophagus. 6. The pylorus. 7. The duodenum, its descending portion. 8. The transverse portion ofthe duodenum. 9. The pancreas. 10. The spleen. 11. The aorta. 12. The cceliac axis. 13. The gastric artery. 14. The hepatic artery. 15. Its pyloric branch. 16. The gastro-duodenalis. 17. The gastro-epiploica dextra. 18. The pancreatico-duodenalis, inosculating with a branch from the superior mesenteric artery. 19. The division of the hepatic artery into its right and left branches; the right giving off the cystic branch. 20. The splenic artery, traced by dotted lines behind the stomach to the spleen. 21. The gastro-epiploica sinistra, inosculating along the great curvature ofthe stomach with the gastro-epiploica dextra. 22. The pancreatica magna. 23. The vasa brevia to the great end of the stomach, inosculating with branches of the gastric artery. 24. The superior mesenteric artery, emerging from between the pancreas and transverse portion if the duodenum. SUPERIOR MESENTERIC ARTERY. 313 tributed to the small intestine from the duodenum to the termination of the ileum. In their course between the layers of the mesentery, they form a series of arches by the inosculation of their larger branches; from these Fig. 154.* are developed secondary arches, and from the latter a third series of arches, from which the branches arise which are distributed to the coats of the in- testine. From the middle branches a fourth and sometimes even a fifth series of arches is produced. By means of these arches a direct commu- nication is established between all the branches given off from the convex- ity of the superior mesenteric artery; the superior branches moreover sup- ply the pancreas and duodenum, and inosculate with the pancreatico- duodenalis ; and the inferior with the ileo-colica. The lleo-colic artery is the last branch given off from the concavity of the superior mesenteric. It descends to the right iliac fossa, and divides into branches winch communicate and form arches, from which branches are distributed to the termination of the ileum, the caecum, and the com- mencement of the colon. This artery inosculates on the one hand with the last branches of the vasa intestini tenuis, and on the other with the last colica dextra. * The course and distribution of the superior mesenteric artery. 1. The descending portion of the duodenum. 2. The transverse portion. 3. The pancreas. 4. The jeju- num. 5. The ileum. 6. The caecum, from which the appendix vermiformis is seen projecting. 7. The ascending colon. 8. The transverse colon. 9. The commencement of the descending colon. 10. The superior mesenteric artery. 11. The colica media. 12. The branch which inosculates with the colica sinistra. 13. The branch ofthe supe- rior mesenteric artery, which inosculates with the pancreatico-duodenalis. 14. The co- lica dextra. 15. The ileo-colica. 16, 16. The branches from the convexity of the supe- rior mesenteric to the small intestines. 21 314 SPERMATIC ARTERIES. The Colica dextra arises from about the middle ofthe concavity of the superior mesenteric, and flivides into branches which form arches, and are distributed to the ascending colon. Its descending branches inosculate with the ileo-colica, and the ascending with the colica media. The Colica media arises from the upper part of the concavity of the su- perior mesenteric, and passes forwards between the layers of the transverse mesocolon, where it forms arches, and is distributed to the transverse colon. It inosculates on the right with the colica dextra ; and on the left with the colica sinistra, a branch of the inferior mesenteric artery. The Spermatic arteries are two small vessels w-hich arise from the front of the aorta below7 the superior mesenteric; from this origin each artery passes obliquely outwards, and accompanies the corresponding ureter along the front of the psoas muscle to the border of the pelvis, where it is in relation with the external iliac artery. It is then directed outwards to the internal abdominal ring, and follows the course of the Fig. 155* * The distribution and branches of the inferior mesenteric artery. 1, 1. The superior mesenteric artery, with its branches and the small intestines turned over to the right side. 2. The capcum and appendix caeci. 3. The ascending colon. 4. The transverse colon raised upwards. 5. The descending colon. 6. Its sigmoid flexure. 7. The rec- tum. 8. The aorta. 9. The inferior mesenteric artery. 10. The colica sinistra, inos- culating with, 11, the colica media, a branch ofthe superior mesenteric artery. 12, 12. Sigmoid branches. 13. The superior haemorrhoidal artery. 14. The pancreas. 15. The descending portion ofthe duodenum. LUMBAR ARTERIES. 315 spermatic cord along the spermatic canal and through the scrotum to the testicle, to which it is distributed. The right spermatic artery lies in front of the vena cava, and both vessels are accompanied by their corresponding veins and by the spermatic plexuses of nerves. The spermatic arteries in the female descend into the pelvis and pass between the tw7o layers of the broad ligaments of the uterus, to be distri- buted to the ovaries, Fallopian tubes, and round ligaments; along the latter they are continued to the inguinal canal and labium at each side. They inosculate with the uterine arteries. The Inferior mesenteric artery, smaller than the superior, arises from the abdominal aorta, about two inches below the origin of that ves- sel, and descends between the layers of the left mesocolon, to the left iliac fossa, where it divides into three branches : Colica sinistra, Sigmoideae, Superior haemorrhoidal. The Colica sinistra is distributed to the descending colon, and ascends to inosculate with the colica media. This is the largest arterial inoscula- tion in the body. The Sigmoidece are several large branches which are distributed to the sigmoid flexure of the descending colon. They form arches, and inoscu- late above with the colica sinistra, and below with the superior haemor- rhoidal artery. The Superior hemorrhoidal artery is the continuation of the inferior mesenteric. It crosses the ureter and common iliac artery ofthe left side, and descends between the two layers of the meso-rectum as far as the middle of the rectum to which it is distributed, anastomosing with the middle and external haemorrhoidal arteries. The Supra-renal are two small vessels which arise from the aorta im- mediately above the renal arteries, and are distributed to the supra-renal capsules. They are sometimes branches of the phrenic or of the renal arteries. The Renal arteries (emulgent) are two large trunks given off from the sides of the aorta immediately below the superior mesenteric artery; the right is longer than the left on account of the position of the aorta, and passes behind the vena cava to the kidney of that side. The left is somewhat higher than the right. They divide into several large branches previously to entering the kidney, and ramify very minutely in its vascular portion. The renal arteries supply several small branches to the supra- renal capsules. The Lumbar arteries correspond with the intercostals in the chest; they are four or five in number on each side, and curve around the bodies of the lumbar vertebrae beneath the psoas muscles, and divide Into two branches • one of w7hich passes backwards between the transverse pro- cesses and is distributed to the vertebrae and spinal cord and to the mus- cles of the back, whilst the other takes its course behind the quadratus lumborum muscle and supplies the abdominal muscles. The first lumbar 316 COMMON ILIAC ARTERIES. artery runs along the lower border of the last rib, and the last along the crest of the ilium. In passing between the psoas muscles and the verte- brae, they are protected by a series of tendinous arches, which defend them and the communicating branches of the sympathetic nerve from pressure during the action of the muscle. The Sacra media arises from the posterior part of the aorta at its bifur- cation, and descends along the middle of the anterior surface of the sacrum to the first piece of the coccyx, where it terminates by inosculating with the lateral sacral arteries. It distributes branches to the rectum and ante- rior sacral nerves, and inosculates on either side with the lateral sacral arteries. Varieties in the Brandies ofthe Abdominal Aorta.—The phrenic arteries are very rarely both derived from the aorta. One or both may be branches of the cceliac axis; one may proceed from the gastric artery, from the renal, or from the upper lumbar artery. There are occasionally three or more phrenic arteries. The coeliac artery is very variable in length, and gives off its branches irregularly. There are sometimes two or even three hepatic arteries, one of which may be derived from the gastric or even from the superior mesenteric. The colica media is sometimes derived from the hepatic artery. The spermatic arteries are very variable, both in origin and number. The right spermatic may be a branch of the renal artery, and the left a branch of the inferior mesenteric. The supra-renal arteries may be derived from the phrenic or renal arteries. The renal arteries present several varieties in number; there may be three or even four arteries on one side, and one only on the other. When there are several renal arteries on one side, one may arise from the common iliac artery, from the front of the aorta near its lower part, or from the internal iliac. common iliac arteries. The abdominal aorta divides opposite the fourth lumbar vertebra into the two common iliac arteries. Sometimes the bifurcation takes place as high as the third, and occasionally as low as the fifth lumbar vertebra. The common iliac arteries are about two inches and a half in length; they diverge from the termination of the aorta, and pass downwards and out- wards on each side to the margin of the pelvis, opposite the sacro-iliac symphysis, where they divide into the internal and external iliac arteries. In old persons the common iliac arteries are more or less dilated and curved in their course. The Right common iliac is somewhat longer than the left, and forms a more obtuse angle with the termination of the aorta; the angle of bifur- cation is greater in the female than in the male. Relations. — The relations of the tw7o arteries are different on the two sides of the body. The right common iliac is in relation in front with the peritoneum, and is crossed at its bifurcation by the ureter. It is in rela- tion posteriorly with the two common iliac veins, and externally with the psoas magnus. The left is in relation in front with the peritoneum, and is crossed by the rectum and superior haemorrhoidal artery, and, at its bifurcation, by the ureter. It is in relation behind with the left common iliac vein, and externally with the psoas magnus. INTERNAL ILIAC ARTERY. 317 INTERNAL ILIAC ARTERY. The Internal Iliac artery is a short trunk, varying in length from an inch to two inches. It descends obliquely to a point opposite the upper margin of the great sacro-ischiatic foramen, where it divides into an ante- rior and a posterior trunk. Fig. 156.» Relations.—This artery rests externally on the sacral plexus and on the origin of the pyriformis muscle; posteriorly it is in relation with the in- ternal iliac vein, and anteriorly with the ureter. Branches.—The branches of the anterior trunk are the— Umbilical, Ischiatic, Middle vesical, Internal pudic. Middle haemorrhoidal, And in the female the— Uterine, Vaginal. And of the posterior trunk, the— Ilio-lumbar, Lateral sacral, Obturator, Gluteal. The umbilical artery is the commencement of the fibrous cord into which the umbilical artery of the foetus is converted after birth. In after life, the cord remains pervious for a short distance, and constitutes the umbilical artery of the adult, from which the superior vesical artery is given off to the fundus and anterior aspect ofthe bladder. The cord may *The distribution and branches ofthe iliac arteries. 1. The aorta. 2. The left com- mon iliac artery. 3. The external iliac. 4. The epigastric artery. 5. The circumflexa ilii. 6. The internal iliac artery. 7. Its anterior tn*ik. 8. Its posterior trunk. 9. The umbilical artery giving off (10) the superior vesical artery. After the origin of this branch, the umbilical artery becomes converted into a fibrous cord—the umbilical liga- ment. ' 11. The internal pudic artery passing behind the spine of the ischium (12) and lesser sacro-ischiatic ligament. 13. The middle haemorrhoidal artery. 14. The ischiatic artery, also passing behind the anterior sacro-ischiatic ligament to escape from the pelvis'. 15. Its inferior vesical branch. 16. The ilio-lumbar, the first branch ofthe pos- terior trunk (8) ascending to inosculate with the circumflexa ilii artery (5) and form an arch along the crest of the ilium. 17. The obturator artery. 18. The lateral sacral. 19. The gluteal artery escaping from the pelvis through the upper part of the great »acro-ischiatic foramen. 20. The sacra media. 21. The right common iliac artery cut thort. 22. The femoral artery. 27* 318 ISCHIATIC AND INTERNAL PUDIC ARTERIES. be traced forwards by the side of the fundus of the bladder to near its apex, whence it ascends by the side of the linea alba and urachus to the umbilicus. The Middle vesical artery is generally a branch of the umbilical, and sometimes of the internal iliac. It is somewhat larger than the superior vesical, and is distributed to the posterior part ofthe body ofthe bladder, the vesiculae seminales, and prostate gland. The Middle hemorrhoidal artery is as frequently derived from the ischiatic or internal pudic as from the internal iliac. It is of variable size, and is distributed to the rectum, base of the bladder, vesiculae seminales, and prostate gland, and inosculates with the superior and external haemor- rhoidal arteries. The Ischiatic artery is the larger of the two terminal branches of the anterior division of the internal iliac. It passes downwards between the posterior border of the levator ani and the pyriformis, resting on the sacral plexus of nerves, and lying behind the internal pudic artery, to the lower border of the great ischiatic notch, where it escapes from the pelvis below the pyriformis muscle. It then descends in the space between the tro- chanter major and the tuberosity of the ischium in company with the ischiatic nerves, and divides into branches. Its branches within the pelvis are hemorrhoidal, which supply the rec- tum conjointly with the middle haemorrhoidal, and sometimes take the place of that artery, and the inferior vesical, which is distributed to the base and neck of the bladder, the vesiculae seminales, and prostate gland. The branches externally to the pelvis, are four in number, namely, coccy- geal, inferior gluteal, comes nervi ischiatici, and muscular branches. The Coccygeal branch pierces the great sacro-ischiatic ligament, and is distributed to the coccygeus and levator ani muscles, and to the integu- ment around the anus and coccyx. The Inferior gluteal branches supply the gluteus maximus muscle. The Comes nervi ischiatici is a small but regular branch, which accom- panies the great ischiatic nerve to the lower part ofthe thigh. The Muscular branches supply the muscles of the posterior part of the hip and thigh, and inosculate with the internal and external circumflex arteries, with the obturator, and with the superior perforating artery. The Internal pudic artery, the other terminal branch of the anterior trunk of the internal iliac, descends in front of the ischiatic artery to the lower border of the great ischiatic foramen. It emerges from the pelvis through the great sacro-ischiatic foramen below- the pyriformis muscle, crosses the spine ofthe ischium, and re-enters the pelvis through the lesser sacrp-ischiatic foramen; it then crosses the internal obturator muscle to the ramus ofthe ischium, being situated at about an inch from the margin of the tuberosity, and bound down by the obturator fascia; it next ascends the ramus of the ischium, enters between the two layers ofthe deep peri- neal fascia lying along the border of the ramus of the os pubis, and at the symphysis pierces the anterior layer of the deep perineal fascia, and, very much diminished in size, reaches the dorsum of the penis along which it runs, supplying that organ under the name of dorsalis penis. Branches.—The branches of the internal pudic artery within the pelvis are several small ramuscules to the base of the bladder, the vesiculae semi- INTERNAL PUDIC ARTERY. 310 nales, and the prostate gland ; and hemorrhoidal branches which supply the middle of the rectum, and frequently take the place of the middle haemorrhoidal branch of the internal iliac. The branches given off externally to the pelvis, are the External haemorrhoidal, Superficialis perinei, Transversalis perinei, Arteria bulbosi, Arteria corporis cavernosi, Arteria dorsalis penis. The External hemorrhoidal arteries are three or four small branches, given off by the internal pudic while behind the tuberosity ofthe ischium. They are distributed to the anus, and to the muscles, the fascia, and the integument of the anal region of the perineum. The Superficial perineal artery is given off near the attachment of the crus penis; it pierces the connecting layer of the superficial and deep perineal fascia, and runs fonvard across the transversus perinei muscle, and along the groove between the accelerator urinae and erector penis to the septum scroti, upon which it ramifies under the name of arteria septi. It distributes branches to the scrotum, and to the perineum in its course forwards. One of the latter, larger than the rest, crosses the perineum, Fig. 157* • The arteries ofthe perineum; on the right side the superficial arteries are seen, and on the left the deep. 1. The penis, consisting of corpus spongiosum and corpus caver- nosum. The crus penis on the left side is cut through. 2. The acceleratores urinas muscles, enclosing the bulbous portion ofthe corpus spongiosum. 3. The erector penis, spread out upon the crus penis of the right side. 4. The anus, surrounded by the sphincter ani muscle. 5. The ramus of the ischium and os pubis. 6. The tuberosity ofthe ischium. 7. The lesser sacro-ischiatic ligament, attached by its small extremity to the spine ofthe ischium. 8. The coccyx. 9. The internal pudic artery, crossing the spine ofthe ischium, and entering the perineum. 10. External hemorrhoidal branches. 11. The superficialis perinei artery, giving off a small branch, transversalis perinei, upon the transversus perinei muscle. 12. The same artery on the left side cut off. 13. The artery ofthe bulb. 14. The two terminal branches of the internal pudic artery; one is seen entering the divided extremity of the crus penis, the artery of the corpus cavernosum; the other, the dorsalis penis, ascends upon the dorsum of the organ. 320 OBTURATOR ARTERY. resting on the transversus perinei muscle, and is named the transversaUs perinei. The Artery of the bulb is given off from the pudic nearly opposite the opening for the transmission of the urethra; it passes almost transversely inwards betw-een the two layers of the deep perineal fascia, and pierces the anterior layer to enter the corpus spongiosum at its bulbous extremity, It is distributed to the corpus spongiosum. The Artery of the corpus cavernosum pierces the crus penis, and runs forward in the interior of the corpus cavernosum, by the side of the septum pectiniforme. It ramifies in the parenchyma ofthe venous structure ofthe corpus cavernosum. The Dorsal artery of the penis ascends between the two crura and sym- physis pubis to the dorsum penis, and runs forward, through the suspensory ligament, in the groove of the corpus cavernosum to the glans, distributing branches in its course to the body of the organ and to the integument. The Internal pudic artery in the female is smaller than in the male; its branches, with their distribution are, in principle, the same. The su- perficial perineal artery supplies the analogue of the lateral half of the scrotum, viz. the greater labium. The artery of the bulb supplies the meatus urinarius, and the vestibule; the artery of the corpus cavernosum, the cavernous body of the clitoris, and the arteria dorsalis clitoridis, the dorsum of that organ. The Uterine and Vaginal arteries of the female are derived either from the internal iliac, or from the umbilical, internal pudic, or ischiatic arteries. The former are very tortuous in their course, and ascend between the layers of the broad ligament, to be distributed to the uterus. The latter ramify upon the exterior of the vagina, and supply its mucous membrane. Branches of the Posterior Trunk. The Ilio-lumbar artery ascends beneath the external iliac vessels and psoas muscle, to the posterior part of the crest of the ilium ; where it di- vides into two branches, a lumbar branch which supplies the psoas and iliacus muscles, and sends a ramuscule through the fifth intervertebral fo- ramen to the spinal cord and its membranes; and an iliac branch which passes along the crest ofthe ilium, distributing branches to the iliacus and abdominal muscles, and inosculating with the lumbar and gluteal arteries, and with the circumflexa ilii. The Obturator artery is exceedingly variable in point of origin; it generally proceeds from the posterior trunk of the internal iliac artery, and passes forwards a little below the brim of the pelvis to the upper border of the obturator foramen. It there escapes from the pelvis through a ten- dinous arch formed by the obturator membrane, and divides into two branches; an internal branch which curves inwards around the bony margin of the obturator foramen, between the obturator externus muscle wid the ramus of the ischium, and distributes branches to the obturator muscles, the pectineus, the adductor muscles, and to the organs of gene- ration, and inosculates with the internal circumflex artery ; and an external branch which pursues its course along the outer margin of the obturator foramen to the space between the gemellus inferior and quadratus femoris, where it inosculates with the ischiatic artery. In its course backwards it EXTERNAL ILIAC ARTERY. 321 anastomoses with the internal circumflex, and sends a branch through the notch in the acetabulum to the hip joint. Within the pelvis the obturator artery gives off a branch to the iliacus muscle, and a small ramuscule which inosculates with the epigastric artery. The Lateral sacral arteries are generally two in number on each side ; superior and inferior. The superior passes inwards to the first sacral foramen, and is distributed to the contents ofthe spinal canal, from which it escapes by the posterior sacral foramen, and supplies the integument on the dorsum of the sacrum. The inferior passes down by the side of the anterior sacral foramina to the coccyx; it first pierces and then rests upon the origin of the pyriformis, and sends branches into the sacral canal to supply the sacral nerves. Both arteries inosculate with each other and with the sacra media. The Gluteal artery is the continuation of the posterior trunk of the internal iliac: it passes backwards between the lumbo-sacral and first lum- bar nerve through the upper part of the great sacro-ischiatic foramen and above the pyriformis muscle, and divides into three branches, superficial, deep superior, and deep inferior. The Superficial branch is directed forwards, between the gluteus maxi- mus and medius, and divides into numerous branches, which are distri- buted to the upper part of the gluteus maximus and to the integument of the gluteal region. The Deep superior branch passes along the superior curved line of the ilium, between the gluteus medius and minimus to the anterior superior spinous process, where it inosculates with the superficial circumflexa ilii and external circumflex artery. There are frequently two arteries which follow this course. The Deep inferior branches are several large arteries which cross the gluteus minimus obliquely to the trochanter major, where they inosculate with the branches of the external circumflex artery, and send branches through the gluteus minimus to supply the capsule ofthe hip joint. Varieties in the Branches of the internal iliac.—The most important of the varieties occurring among these branches is the origin of the dorsal artery of the penis from the internal iliac or ischiatic. The artery in this case passes forwards by the side of the prostate gland, and through the upper part of the deep perineal fascia. It would be endangered in the operation of lithotomy. The dorsal artery of the penis is sometimes de- rived from the obturator, and sometimes from one of the external pudic arteries. The artery of the bulb, in its normal course, passes almost transversely inwards to the corpus spongiosum. Occasionally, however, it is so oblique in its direction as to render its division in lithotomy un- avoidable. The obturator artery may be very small or altogether want- ing, its place being supplied by a branch from the external iliac or epi- gastric. EXTERNAL ILIAC ARTERY. The external iliac artery of each side passes obliquely downwards along the inner border of the psoas muscle, from opposite the sacro-iliac sym- physis to the femoral arch, where it becomes the femoral artery. Relations.—It is in relation in front with the spermatic vessels, the v 322 EXTERNAL ILIAC ARTERY. peritoneum, and a thin layer of fascia, derived from the iliac fascia, which surrounds the artery and vein. At its commencement it is crossed by the ureter, and near its termination by the crural branch of the genito-crural nerve and the circumflexa ilii vein. Externally it lies against the psoas muscle, from which it is separated by the iliac fascia ; and posteriorly it is in relation with the external iliac vein, which, at the femoral arch, becomes placed to its inner side. The artery is surrounded throughout the whole of its course by lymphatic vessels and glands. Branches.—Besides several small branches which supply the glands surrounding the artery, the external iliac gives off two branches, the— Epigastric, Circumflexa ilii. The Epigastric artery arises from the external iliac near Poupart's liga- ment ; and passing forwards between the peritoneum and transversalis fascia, ascends obliquely to the sheath of the rectus. It enters the sheath near its lower third, and passes upwards behind the rectus muscle, to which it is distributed, and in the substance of that muscle inosculates, near the ensiform cartilage, with the termination of the internal mammary artery. It lies internally to the internal abdominal ring and immediately above the femoral ring, and is crossed near its origin by the vas deferens in the male, and by the round ligament in the female. The only branches of the epigastric artery worthy of distinct notice are the Cremasteric, which accompanies the spermatic cord and supplies the cremaster muscle; and the ramusculus which inosculates with the obtura- tor artery. The epigastric artery forms a prominence of the peritoneum which di- vides the iliac fossa into an internal and an external portion; it is from the former that direct inguinal hernia issues, and from the latter, oblique inguinal hernia. The Circumflexa ilii arises from the outer side of the external iliac, nearly opposite the epigastric artery. It ascends obliquely along Pou- part's ligament, and curving around the crest of the ilium between the attachments of the internal oblique and transversalis muscle, inosculates with the ilio-lumbar and inferior lumbar artery. Opposite the anterior superior spinous process of the ilium, it gives off a large ascending branch w7hich passes upwards between the internal oblique and transversalis, and divides into numerous branches which supply the abdominal muscles, and inosculate with the inferior intercostal and with the lumbar arteries. Varieties in the branches of the external iliac.—The epigastric artery not unfrequently* gives off the obturator, which descends in contact with the external iliac vein, to the obturator foramen. In this situation the artery would lie to the outer side of the femoral ring, and would not be endan- gered in the operation for dividing the stricture of femoral hernia. But occasionally the obturator passes along the free margin of Gimbernat's ligament in its course to the obturator foramen, and would completely en- circle the neck of the hernial sac,—a position in which it could scarcely * The proportion in which high division of the obturator artery from the epigastric occurs, is stated to be one in three. In two hundred and fifty subjects examined by Cloquet with a view to ascertain how frequently the high division took place, he found the obturator arising from the epigastric on both sides one hundred and fifty times; on one side twenty-eight times, and six times it arose from the femoral artery. FEMORAL ARTERY. 323 escape the knife of the operator. In a preparation in my anatomical col- lection, the branch of communication between the epigastric and obturator arteries is very much enlarged, and takes this dangerous course. FEMORAL ARTERY. Emerging from beneath Poupart's ligament, the r'g- l58- external iliac artery enters the thigh and becomes the femoral. The femoral artery passes down the inner side of the thigh, from Poupart's ligament, at a point midway between the anterior superior spinous process of the ilium and the symphysis pubis, to the opening in the adductor magnus, at the junction of the middle with the inferior third of the thigh, where it becomes the popliteal artery. The femoral artery and vein are enclosed in a strong sheath, femoral or crural canal, which is formed for the greater part of its extent by aponeu- rotic and areolar tissue, and by a process of fascia sent inwards from the fascia lata. Near Poupart's ligament this sheath is much larger than the vessels it contains, and is continuous with the fascia trans- versalis and iliac fascia. If the sheath be opened at this point, the artery will be seen to be situated in contact with the outer wall of the sheath. The vein lies next the artery, being separated from it by a fibrous septum, and between the vein and the inner wall of the sheath, and divided from the vein by another thin fibrous septum, is a triangular in- terval, into which the sac is protruded in femoral hernia. This space is occupied in the normal state ofthe parts by loose areolar tissue, and by lympha- tic vessels which pierce the inner wall of the sheath to make their way to a gland, situated in the femo- ral ring. Relations. — The upper third of the femoral ar- tery is superficial, being covered only by the integument, inguinal glands, * A view of the anterior and inner aspect of the thigh, showing the course and branches of the femoral artery. 1. The lower part of the aponeurosis of the externa oblique muscle; its inferior margin is Poupart's ligament. 2. The external abdominal ring 3 3 The upper and lower part of the sartorius muscle; its middle portion having been removed. 4. The rectus. 5. The vastus internus. 6. The patella. 7. The iliacus and psoas; the latter being nearest the artery. 8. The pectineus 9. Ihe adductor longus. 10. The tendinous canal for the femoral artery formed by the adduc- tor magnus, and vastus internus muscle. 11. The adductor magnus 12 The gracilis 13 The tendon of the semi-tendinosus. 14. The femoral artery. 15. The superficial circumflexa ilii artery taking its course along the line of Poupart's ligament to the crest ofthe ilium 2. The superficial epigastric artery. 16. The two external pudic arterie*, sunerficial and deep 17. The profunda artery, giving off 18, its external circumflex branch ■ and lower down the three perforates. A small bend of the internal circum- flex arterv (8) is seen behind the inner margin of the femoral, just below the deep ex- ternal pudic artery. 19. The anastomotica magna, descending to the knee, upon which it ramifies (6). 324 FEMORAL ARTERY. and by the superficial and deep fasciae. The lower two-thirds are covered by the sartorius muscle. To its outer side the artery is first in relation with the psoas and iliacus, and then with the vastus internus. Behind it rests upon the inner border of the psoas muscle ; it is next separated from the pectineus by the femoral vein, profunda vein and artery, and then lies on the adductor longus to its termination: near the lower border of the adductor longus, it is placed in an aponeurotic canal, formed by an arch of tendinous fibres, thrown from the border of the adductor longus and the border of the opening in the adductor magnus, to the side of the vastus internus. To its inner side it is in relation at its upper part with the femoral vein, and lower dowm with the pectineus, adductor longus, and sartorius. The immediate relations of the artery are the femoral vein, and two saphenous nerves. The vein at Poupart's ligament lies to the inner side of the artery; but lower down gets altogether behind it, and inclines to its outer side. The short saphenous nerve lies to the outer side, and some- what upon the sheath for the lower two-thirds of its extent; and the long saphenous nerve is situated within the sheath, and in front of the artery for the same extent. Plan of the Relations of the Femoral Artery. Front. Fascia lata, Saphenous nerves, Sartorius, Arch of the tendinous canal. Inner Side. Femoral vein, Pectineus, Adductor longus, Sartorius. Femoral artery. Outer Side. Psoas, Iliacus, Vastus internus. Behind. Psoas muscle, Femoral vein, Adductor longus. Branches.—The branches of the Femoral Artery are the— Superficial circumflexa ilii, Superficial epigastric, Superficial external pudic, Deep external pudic, C External circumflex, Profunda < Internal circumflex, ( Three perforating, Muscular, Anastomotica magna. _ The Superficial circumflexa ilii artery arises from the femoral, imme- diately below Poupart's ligament, pierces the fascia lata, and passes ob- PROFUNDA ARTERY. 325 liquely outwards towards the crest of the ilium. It supplies the integument of the groin, the superficial fascia, and inguinal glands. The Superficial epigastric arises from the femoral, immediately below Poupart's ligament, pierces the fascia lata, and ascends obliquely towards the umbilicus between the two layers of superficial fascia. It distributes branches to the inguinal glands and integument, and inosculates with branches of the deep epigastric and internal mammary artery. The Superficial external pudic arises near the superficial epigastric artery; it pierces the fascia lata, at the saphenous opening, and passes transversely inwards, crossing the spermatic cord, to be distributed to the integument of the penis and scrotum in the male, and to the labia in the female. The Deep external pudic arises from the femoral, a little lower down than the preceding: it crosses the femoral vein immediately below the termination of the internal saphenous vein, and piercing the pubic portion of the fascia lata, passes beneath that fascia to the inner border of the thigh, where it again pierces the fascia; having become superficial, it is distributed to the integument of the scrotum and perineum. The Profunda femoris arises from the femoral artery at two inches below Poupart's ligament: it passes downwards and backwards and a little outwards, behind the adductor longus muscle, pierces the adductor magnus, and is distributed to the flexor muscles on the posterior part of the thigh. Relations.—In its course downwards it rests successively upon the pecti- neus, the conjoined tendon of the psoas and iliacus, adductor brevis, and adductor magnus muscles. To its outer side the tendinous insertion of the vastus internus muscle intervenes between it and the femur; on its inner side it is in relation with the pectineus, adductor brevis, and adduc- tor magnus; and in front it is separated from the femoral artery, above by the profunda vein and femoral vein, and below by the adductor longus muscle. Plan of the Relations of the Profunda Artery. In Front. Profunda vein, Adductor longus. Inner Side. Pectineus, Adductor brevis, Adductor magnus. Profunda artery. Outer Side. Psoas and iliacus, Vastus internus, Femur. Behind. Pectineus, Tendon of psoas and iliacus, Adductor brevis, Adductor magnus. Brandies.__The branches of the profunda artery are, the external cir- cumflex, internal circumflex, and three perforating arteries. The External circumflex artery passes obliquely outwards between the 28 326 POPLITEAL ARTERY. divisions ofthe crural nerve, then between the rectus and crureus muscle, and divides into three branches; ascending, which inosculates with the terminal branches of the gluteal artery; descending, which inosculates with the superior external articular artery; and middle, which continues the original course ofthe artery around the thigh, and anastomoses with branches of the ischiatic, internal circumflex, and superior perforating artery. It supplies the muscles on the anterior and outer side of the thigh. The Internal circumflex artery is larger than the external; it winds around the inner side of the neck of the femur, passing between the pecti- neus and psoas, and along the border of the external obturator muscle, to the space between the quadratus femoris and upper border ofthe adductor magnus, where it anastomoses with the ischiatic, external circumflex, and superior perforating artery. It supplies the muscles of the upper and inner side ofthe thigh, anastomosing with the obturator artery, and sends a small branch through the notch in the acetabulum into the hip joint. The Superior perforating artery passes backwards between the pectineus and adductor brevis, pierces the adductor magnus near the femur, and is distributed to the posterior muscles of the thigh; inosculating freely with the circumflex and ischiatic arteries, and with the branches of the middle perforating artery. The Middle perforating artery pierces the tendons ofthe adductor brevis and magnus, and is distributed like the superior; inosculating with the superior and inferior perforantes. This branch frequently gives off the nutritious artery of the femur. The Inferior perforating artery is given off below the adductor brevis, and pierces the tendon of the adductor magnus, supplying it and the flexor muscles, and inosculating with the middle perforating artery above, and with the articular branches of the popliteal below. It is through the me- dium of these branches that the collateral circulation is maintained in the limb after ligature of the femoral artery. The Muscular branches are given off by the femoral artery throughout the whole of its course. They supply the muscles in immediate proximity with the artery, particularly those ofthe anterior aspect ofthe thigh. One of these branches, larger than the rest, arises from the femoral immediately below the origin of the profunda, and passing outwards between the rectus and sartorius divides into branches which are distributed to all the muscles of the anterior aspect of the thigh. This may be named the superior mus- cular artery. The Anastomotica magna arises from the femoral while in the tendinous canal formed by the adductors and vastus internus. It runs along the ten- don of the adductor magnus to the inner condyle, and inosculates with the superior internal articular artery; some of its branches are distributed to the vastus internus muscle and to the crureus, and terminate by anasto- mosing with the branches of the external circumflex and superior external articular artery. popliteal artery. The popliteal artery (Fig. 160) commences from the termination of the femoral at the opening in the adductor magnus muscle, and passes obliquely outwards through the middle ofthe popliteal space to the lower border of the popliteus muscle, where it divides into the anterior and posterior tibial artery. POPLITEAL ARTERY. 327 Relations.—In its course downwards it rests first on the femur, then on the posterior ligament of the knee joint, then on the fascia, covering the popliteus muscle. Superficially it is in relation with the semi-membranosus muscle, next with a quantity of fat which separates it from the deep fascia, and near its termination with the gastrocnemius plantaris, and soleus; superficial and external to it is the popliteal vein, and still more superficial and external, the popliteal nerve. By its inner side it is in relation with the semi-membranosus, internal condyle of the femur, and inner head of the gastrocnemius; and by its outer side with the biceps, external condyle of the femur, the outer head of the gastrocnemius, the plantaris and the soleus. Plan of the Relations of the Popliteal Artery. Superficially. Semi-membranosus, Popliteal nerve, Popliteal vein, Gastrocnemius, Plantaris, Soleus. Inner Side. Semi-membranosus, Internal condyle, Gastrocnemius. Popliteal Artery. Outer Side. Biceps, External condyle, Gastrocnemius, Plantaris, Soleys. Deeply. Femur, Ligamentum posticum Winslowii, Popliteal fascia. Branches.—The branches of the popliteal artery are the Superior external articular, Superior internal articular, Azygos articular, Inferior external articular, Inferior internal articular, Sural. The Superior articular arteries, external and internal, wind around the femur, immediately above the condyles, to the front of the knee joint, anastomosing with each other, with the external circumflex, the anasto- motica magna, the inferior articular, and the recurrent of the anterior tibial. The external passes beneath the tendon of the biceps, and the internal through an arched opening beneath the tendon of the adductor magnus. They supply the knee joint and the lower part of the femur. The Azygos articular artery pierces the posterior ligament of the joint, the ligamentum posticum Winslowii, and supplies the synovial membrane in its interior. There are, frequently, several posterior articular arteries. The Inferior articular arteries wind around the head of the tibia imme- diately below the joint, and anastomose with each other, the superior articular arteries and the recurrent of the anterior tibial. The external passes beneath the two external lateral ligaments of the joint, and the in- 328 ANTERIOR TIBIAL ARTERY. Fig. 159.* ternal beneath the internal lateral ligament. They supply the knee joint and the heads of the tibia and fibula. The Sural arteries (sura, the calf) are two large muscular branches, which are distributed to the two heads of the gastrocnemius muscle. anterior tibial artery. The anterior tibial artery passes forwards between the two heads of the tibialis posticus muscle, and through the opening in the upper part of the inter- osseous membrane, to the anterior tibial region. It then runs down the anterior aspect of the leg to the ankle joint, where it becomes the dorsalis pedis. Relations.—In its course downw7ards it rests upon the interosseous membrane (to which it is connected by a little tendinous arch which is thrown across it), the lower part of the tibia, and the anterior ligament of the joint. In the upper third of its course it is situated betw-een the tibialis anticus and extensor longus digitorum, lower down between the tibialis i_y anticus and extensor proprius pollicis; and just be- fore it reaches the ankle it is crossed by the tendon of the extensor proprius pollicis, and becomes placed between that tendon and the tendons of the extensor longus digitorum. Its immediate relations are the venae comites and the anterior tibial nerve, which latter lies at first to its outer side, and at about the middle of the leg becomes placed superficially to the artery. Plan of the Relations of the Anterior Tibial Artery. Front. Deep fascia, Tibialis anticus, Extensor longus digitorum, Extensor proprius pollicis, Anterior tibial nerve. Inner Side. Tibialis anticus, Tendon of the ex- tensor proprius pollicis. Anterior Tibial Artery. Outer Side. Anterior tibial nerve, Extensor longus digitorum, Extensor proprius pollicis, Tendons of the extensor longus digitorum. Behind. Interosseous membrane, Tibia (lower fourth), Ankle joint. * The anterior aspect of the leg and foot, showing the anterior tibial and dorsalis pedis arteries, with their branches. 1. The tendon of insertion of the quadriceps ex- tensor muscle. 2. The insertion ofthe ligamentum patellae into the lower border of the patella. 3. The tibia. 4. The extensor proprius pollicis muscle. 5. The extensor lon- gus digitorum. 6. The peronei muscles. 7. The inner belly of the gastrocnemius and DORSALIS PEDIS ARTERY. 329 Branches.—The branches of the Anterior Tibial Artery are the— Recurrent, Muscular, External malleolar, Internal malleolar. The Recurrent branch passes upwards beneath the origin of the tibialis anticus muscle to the front of the knee joint, upon which it is distributed, anastomosing with the articular arteries. The Muscular branches are very numerous, they supply the muscles of the anterior tibial region. The Malleolar arteries are distributed to the ankle joint; the external passing beneath the tendons of the extensor longus digitorum and pero- neus tertius, inosculates with the anterior peroneal artery %and with the branches of the dorsalis pedis ; the internal, beneath the tendons of the extensor proprius pollicis and tibialis anticus, inosculates with branches of the posterior tibial and internal plantar artery. They supply branches to the ankle joint. The Dorsalis pedis artery is continued forward along the tibial side of the dorsum of the foot, from the ankle to the base of the metatarsal bone of the great toe, where it divides into two branches, the dorsalis hallucis and communicating. Relations.—The dorsalis pedis is situated along the outer border of the tendon of the extensor proprius pollicis; on its fibular side is the inner- most tendon of the extensor longus digitorum, and near its termination it is crossed by the inner tendon of the extensor brevis digitorum. It is ac- companied by venae comites, and has the continuation of the anterior tibial nerve to its outer side. Plan of the Relations of the Dorsalis Pedis Artery. In Front. Integument, Deep fascia, Inner tendon of the extensor brevis digitorum. Inner Side. Tendon of the ex- tensor proprius pollicis. Dorsalis Pedis Artery. Outer Side. Fendon of the extensor longus digitorum, Border of the extensor brevis digitorum muscle. Behind. Bones of the tarsus, with their ligaments the soleus. 8. The annular ligament beneath which the extensor tendons and the an terior tibial artery pass into the dorsum of the foot. 9. The anterior tibial artery. 10. Its recurrent branch inosculating with (2) the inferior articular, and (1) the superior articular arteries, branches of the popliteal. 11. The internal malleolar artery. 17. The external malleolar inosculating with the anterior peroneal artery 12. 13. The dor- salis pedis artery. 11. The tarsea and metatarsea arteries; the tarsea is nearest the ankle the metatarsea is seen giving off the interosseae. 15. The dorsalis hallucis artery. 16. The communicating branch. 28* 330 POSTERIOR TIBIAL ARTERY. Brandies.—The branches of this artery are the— Tarsea, Metatarsea,—interosseae, Dorsalis hallucis,—collateral digital, Communicating. The Tarsea arches transversely across the tarsus, beneath the extensor brevis digitorum muscle, and supplies the articulations of the tarsal bones and the outer side of the foot; it anastomoses with the external malleolar, the peroneal arteries, and the external plantar. p. m The Metatarsea forms an arch across the base of the metatarsal bones, and supplies the outer side of the foot; anastomosing with the tarsea and with the exter- nal plantar artery. The metatarsea gives off three branches, the interossee, which pass forw-ard upon the dorsal interossei muscles, and divide into two collateral branches for adjoining toes. At their commencement these interosseous branches receive the posterior per- forating arteries from the plantar arch, and opposite the heads of the metatarsal bones they are joined by the anterior perforating branches from the digital arteries. The Dorsalis hallucis runs forward upon the first dor- sal interosseous muscle, and at the base of the first phalanx divides into two branches, one of which passes inwards beneath the tendon of the extensor proprius pollicis, and is distributed to the inner border of the great toe, while the other bifurcates for the supply of the adjacent sides ofthe great and second toe. The Communicating artery passes into the sole of the foot between the two heads of the first dorsal interos- seous muscle, and inosculates with the termination of the external plantar artery. Besides the preceding, numerous branches are dis- tributed to the bones and articulations of the foot, par- ticularly along the inner border of the latter. POSTERIOR TIBIAL ARTERY. The posterior tibial artery passes obliquely down- wards along the tibial side of the leg from the lower * A posterior view of the leg, showing the popliteal and posterior tibial artery. 1. The tendons forming the inner hamstring. 2. The tendon of the biceps forming the outer hamstring. 3. The popliteus muscle. 4. The flexor longus digitorum. 5. The tibialis posticus. 6. The fibula; immediately below the figure is the origin ofthe flexor longus pollicis; the muscle has been removed in order to expose the peroneal artery. 7. The peronei muscles, longus and brevis. 8. The lower part of the flexor longus pollicis muscle with its tendon. 9. The popliteal artery giving off its articular and muscular branches; the two superior articular are seen in the upper part of the popli- teal space passing above the two heads of the gastrocnemius muscle, which are cut through near their origin. The two inferior are in relation with the popliteus muscle. 10. The anterior tibial artery passing through the angular interspace between the two heads ofthe tibialis posticus muscle. 11. The posterior tibial artery. 12. The relative position of the tendons and arteiy at the inner ankle from within outwards, previously to their passing beneath the internal annular ligament. 13. The peroneal artery, dividing, a little below the number, into two branches; the anterior peroneal is seen piercing the interosseous membrane. 14. The posterior peroneal POSTERIOR TIBIAL AND PERONEAL ARTERIES. 331 border of the popliteus muscle to the concavity of the os calcis, where it divides into the internal and external plantar artery. Relations.—In its course downwards it lies first upon the tibialis posti- cus, next on the flexor longus digitorum, and then on the tibia; it is covered in by the intermuscular fascia which separates it above from the soleus, and below from the deep fascia ofthe leg and the integument. It is accompanied by its venae comites, and by the posterior tibial nerve, which latter lies at first to its outer side, then superficially to it, and again to its outer side. Plan of the Relations of the Posterior Tibial Artery. Superficially. Soleus, Deep fascia, The intermuscular fascia. Outer Side. Posterior tibial nerve, Vein. Deeply. Tibialis posticus, Flexor longus digitorum, Tibia. Branches.—The branches of the posterior tibial artery are the— Peroneal, Internal calcanean, Nutritious, Internal plantar, Muscular, External plantar. The Peroneal artery is given off from the posterior tibial at about two inches below the lower border of the popliteus muscle; it is nearly as large as the anterior tibial artery, and passes obliquely outwards to the fibula. It then runs downwards along the inner border of the fibula to its lower third, where it divides into the anterior and posterior peroneal artery. Relations.—The peroneal artery rests upon the tibialis posticus muscle, and is covered in by the soleus, the intermuscular fascia, and the flexor jongus pollicis, having the fibula to its outer side. Plan oftlie Relations ofthe Peroneal Artery. In Front. Soleus, Intermuscular fascia, Flexor longus pollicis. Peroneal Artery. Inner Side. Vein. Posterior Tibial Artery. Outer Side. Fibula. Behind. Tibialis posticus. 332 PLANTAR ARTERIES. Branches. — The branches of the peroneal artery are, muscular to the neighbouring muscles, particularly to the soleus, and the two terminal branches anterior and posterior peroneal. The Anterior peroneal pierces the interosseous membrane at the lower third of the leg, and is distributed on the front of the outer malleolus, anastomosing with the external malleolar and tarsal artery. This branch is very variable in size. The Posterior peroneal continues onwards along the posterior aspect of the outer malleolus to the side of the os calcis, to which and to the mus- cles arising from it, it distributes external calcanean branches. It anasto- moses with the anterior peroneal, tarsal, external plantar, and posterior tibial artery. The JVutritious artery of the tibia arises from the trunk of the tibial, frequently above the origin of the peroneal, and proceeds to the nutritious canal, which it traverses obliquely from below upwards. The Muscular branches of the posterior tibial artery are distributed to the soleus and to the deep muscles on the posterior aspect of the leg. One of these branches is deserving of notice, a recurrent branch, which arises from the posterior tibial above the origin of the peroneal artery, pierces the soleus, and is distributed upon the inner side of the head of the tibia, anastomosing with the inferior internal articular. The Internal calcanean branches, three or four in number, proceed from the posterior tibial artery immediately before its division ; they are distri- buted to the inner side of the os calcis, to the integument, and to the muscles which arise from its inner tuberosity, and they anastomose with the external calcanean branches, and with all the neighbouring arteries. Fig. 161.« PLANTAR ARTERIES. The Internal plantar artery proceeds from the bifur- cation of the posterior tibial at the inner malleolus, and passes along the inner border of the foot between the abductor pollicis and flexor brevis digitorum mus- cles, supplying the inner border of the foot and great toe. The External plantar artery, much larger than the internal, passes obliquely outw7ards between the first and second layers of the plantar muscles, to the fifth metatarsal space. It then turns horizontally inwards between the second and third layers, to the first meta- tarsal space, where it inosculates with the communi- cating branch from the dorsalis pedis. The horizontal portion of the artery describes a slight curve, having the convexity forwards ; this is the plantar arch. Branches. — The branches of the external plantar artery are the— Muscular, Articular, Digital,—anterior perforating, Posterior perforating. * The arteries of the sole of the foot; the first and a part of the second layer of mus- cles having been removed. 1. The under and posterior part ofthe os calcis; to which the origins ofthe first layer of muscles remain attached. 2. The musculus accessorius VARIETIES IN THE ARTERIES OF THE LOWER EXTREMITY. 333 The Muscular branches are distributed to the muscles in the sole of the foot. The Articular branches supply the ligaments of the articulations of the tarsus, and their synovial membranes. The Digital branches are four in number: the first is distributed to the outer side of the little toe ; the three others pass forwards to the cleft be- tween the toes, and divide into collateral branches, which supply the adjacent sides ofthe three external toes, and the outer side ofthe second. At the bifurcation of the toes, a small branch is sent upwards from each digital artery, to inosculate with the interosseous branches of the metatar- sea ; these are the anterior perforating arteries. The Posterior perforating are three small branches which pass upwards between the heads of the three external dorsal interossei muscles to inos- culate with the arch formed by the metatarsea artery. Varieties in the Arteries of the Lower Extremity.—The femoral artery occasionally divides at Poupart's ligament into two branches, and some- times into three; the former is an instance of the high division of the pro- funda artery; and in a case of the latter kind which occurred during my dissections, the branches were the profunda, the superficial femoral, and the internal circumflex artery. Dr. Quain, in his " Elements of Anatomy," records an instance of a high division of the femoral artery, in which the two vessels became again united in the popliteal region. The point of origin of the profunda artery varies considerably in different subjects, being sometimes nearer to and sometimes farther from Poupart's ligament, but more frequently the former. The branches of the popliteal artery are very liable to variety in size; and in all these cases the compensating principle, so constant in the vascular system, is strikingly manifested. When the anterior tibial is of small size, the peroneal is large; and, in place of dividing into two terminal branches at the lower third of the leg, descends to the lower part of the interosseous membrane, and emerges upon the front of the ankle, to supply the dorsum of the foot: or the pos- terior tibial and plantar arteries are large, and the external plantar is con- tinued between the heads of the first dorsal interosseous muscle, to be distributed to the dorsal surface of the foot. Sometimes the posterior tibial artery is small and thread-like; and the peroneal, after descending to the ankle, curves inwards to the inner malleolus, and divides into the two plantar arteries. If, in this case, the posterior tibial be sufficiently large to reach the ankle, it inosculates with the peroneal previously to its division. The internal plantar artery sometimes takes the distribution of the external plantar, which is short and diminutive, and the latter not un- frequently replaces a deficient dorsalis pedis. The varieties of arteries are interesting in the practical application of a knowledge of their principal forms to surgical operations; in their tran- scendental anatomy, as illustrating the normal type of distribution in ani- mals ; or, in many cases, as diverticula permitted by Nature, to teach her observers two important principles -.—first, in respect to herself, that, how- ever in her means she may indulge in change, the end is never overlooked, and a limb is as surely supplied by a leash of arteries, various in their 3. The long flexor tendons. 4. The tendon ofthe peroneus longus. 5. The termination ofthe posterior tibial artery. 6. The internal plantar. 7. The external plantar artery 8. The plantar arch giving off four digital branches, which pass forwards on the inter- ossei muscles. Three of these arteries are seen dividing, near the heads of the meta- tarsal bones, into collateral branches for adjoining toes. 334 OF THE VEINS. course, as by those which w7e are pleased to consider normal in distnbu tion; and, secondly, with regard to us, that we should ever be keenly alive to what is passing beneath our observation, and ever ready in the most serious operation to deviate from our course and avoid—or give eyes to our knife, that it may see,—the concealed dangers which it is our pride to be able to contend with and vanquish. PULMONARY ARTERY. The pulmonary artery arises from the left side of the base of the right ventricle in front of the origin of the aorta, and ascends obliquely to the under surface of the arch of the aorta, where it divides into the right and left pulmonary arteries. In its course upwards and backwards it inclines to the left side, crossing the commencement of the aorta, and is connected to the under surface of the arch by a thick and impervious cord, the re- mains of the ductus arteriosus. delations.—It is enclosed for one-half of its extent by the pericardium, and receives the attachment of the fibrous portion of that membrane by its upper portion. Behind, it rests against the ascending aorta; on either sid' is the appendix of the corresponding auricle with a coronary artery; ar above, the cardiac ganglion and the remains of the ductus arteriosus, ae Right pulmonary artery passes beneath the arch and behind the iscending aorta, and in the root of the lungs divides into three branches for the three lobes. The Left pulmonary artery, rather larger than the right, passes in front of the descending aorta, to the root of the left lung, to which it is distri- buted. These arteries divide and subdivide in the structure of the lungs, and terminate in capillary vessels which form a network around the air- passages and cells, and become continuous with the radicles of the pul- monary veins. Relations.—In the root of the right lung, examined from above down- wards, the pulmonary artery is situated between the bronchus and pulmo- nary veins, the former being above, the latter below; w7hile in the left lung the artery is the highest, next the bronchus, and then the veins. On both sides, from before backwards, the artery is situated between the veins and bronchi, the former being in front, and the latter behind. CHAPTER VII. OF THE VEINS. The veins are the vessels which return the blood to the auricles of the heart, after it has been circulated by the arteries through the various tis- sues of the body. They are much thinner in structure than the arteries, so that wiien emptied of their blood they become flattened and collapsed. The veins of the systemic circulation convey the dark-coloured and im- pure or venous blood from the capillary system to the right auricle of the heart, and they are found after death to be more or less distended with that fluid. The veins of the pulmonary circulation resemble the arteries of the systemic circulation in containing during life the pure or arterial STRUCTURE OF VEINS. 335 blood, which they transmit from the capillaries of the lungs to the left auricle. The veins commence by minute radicles in the capillaries which are everywhere distributed through the textures of the body, and converge to constitute larger and larger branches, till they terminate in the main trunks which convey the venous blood directly to the heart. In diameter they are larger than the arteries, and, like those vessels, their combined areae would constitute an imaginary cone, whereof the apex is placed at the heart, and the base at the surface of the body. It follows from this ar- rangement, that the blood in returning to the heart is passing from a larger into a smaller channel, and therefore that it increases in rapidity during its course. Veins admit of a threefold division into, superficial, deep, and sinuses. The Superficial veins return the blood from the integument and super- ficial structures, and take their course between the layers of the superficial fascia; they then pierce the deep fascia in the most convenient and pro- tected situations, and terminate in the deep veins. They are unaccompa- nied by arteries, and are the vessels usually selected for venesection. The Deep veins are situated among the deeper structures of the bdy, and o-enerally in relation with the arteries ; in the limbs they are end d \i tl°e same sheath with those vessels, and they return the venous b J from the capillaries of the deep tissues. In company with all the sma. y and also with the secondary arteries, as the brachial, radial, and ulnai .a the upper, and the tibial and peroneal in the lower extremity, there are two veins, placed one on each side ofthe artery, and named vena comites. The larger arteries, as the axillary, subclavian, carotid, popliteal, femoral, &c, are accompanied by a single venous trunk. Sinuses differ from veins in their structure; and also in their mode of distribution, being confined to especial organs and situated within their substance. The principal venous sinuses are those of the dura mater, the diploe, the cancellous structure of bones, and the uterus. The communications between veins are even more frequent than those of arteries, and they take place between the larger as w7ell as among the smaller vessels; the venae comites communicate with each other very fre- quently in their course, by means of short transverse branches which pass across from one to the other. These communications are strikingly ex- hibited in the frequent inosculations of the spinal veins, and in the various venous plexuses, as the spermatic plexus, vesical plexus, &c. The office of these inosculations is very apparent, as tending to obviate the obstruc- tions to which the veins are particularly liable from the thinness of then coats, and from their inability to overcome much impediment by the force of their current. Veins, like arteries, are composed of three coats, external or areolo- fibrous, middle or fibrous, and internal or serous. The external coat is firm and strong, and resembles that of arteries. The middle coat consists of two layers an outer layer of contractile fibrous tissue disposed in a cir- cular direction around the vessel, and an inner layer of organic muscular fibres arranged longitudinally. This latter resembles the inner layer of the middle coat of arteries, but is somewhat thicker; it is not unfrequently hvpertrophied. The internal coat, as in arteries, consists of a striated or fenestrated layer, and a layer of epithelium; it is continuous with the in- ternal coat of arteries through the medium of the lining membrane of the 336 VEINS OF THE HEAD AND NECK. heart on the one hand, and through the capillary vessels on the other. The differences in structure, therefore, between arteries and veins, relate to the difference of thickness of their component layers, and to the absence of the elastic coat in the latter. Moreover, another difference occurs in the presence of valves. The valves of veins are composed of a thin layer of fibrous membrane, lined upon its two surfaces by epithelium. The segments or flaps of the valves of veins are semilunar in form and arranged in pairs, one upon either side of the vessel; in some instances there is but a single flap, which has a spiral direction, and occasionally there are three. The free border of the valvular flaps is concave, and directed forwards, so that while the current of blood is permitted to flow freely towards the heart, the valves are distended and the current intercepted if the stream become retrograde in its course. Upon the cardiac side of each valve the vein is expanded into tw7o pouches (sinuses), corresponding with the flaps of the valves, which give to the distended or injected vein a knotted ap- pearance. The valves are most numerous in the veins of the extremities, particularly in the deeper veins, and they are generally absent in the very small veins, and in the veins of the viscera, as in the portal and cerebral veins: they are also absent in the large trunks, as in the venae cavae, venae azygos, innominatae, and iliac veins. Sinuses are venous channels, excavated in the structure of an organ, and lined by the internal coat of the veins; of this structure are the sinuses of the dura mater, whose external covering is the fibrous tissue of the membrane, and the internal, the serous layer of the veins. The external investment of the sinuses of the uterus is the tissue of that organ; and that of the bones, the lining membrane of the cells and canals. Veins, like arteries, are supplied with nutritious vessels, the vasa vaso- rum; and it is to be presumed that nervous filaments are distributed in their coats. I shall describe the veins according to the primary division ofthe body, taking first, those of the head and neck; next, those of the upper extre- mity ; then, those of the lower extremity; and lastly, the veins of the trunk. VEINS OF THE HEAD AND NECK. The veins ofthe head and neck may be arranged into three groups, viz. 1. Veins ofthe exterior ofthe head. 2. Veins of the diploe and interior of the cranium. 3. Veins of the neck. The veins of the exterior of the head are the— Facial, Internal maxillary, Temporal, Temporo-maxillary, Posterior auricular, Occipital. The Facial vein commences on the anterior part of the skull in a venous plexus, formed by the communications of the branches of the temporal, and descends along the middle line of the forehead, under the name of frontal vein, to the root of the nose, where it is connected with its fellow ofthe opposite side by a communicating trunk which constitutes the nasal arch. There are usually two frontal veins, which communicate by a trans- VEINS OF THE DIPLOE. 337 verse inosculation ; but sometimes the vein is single and bifurcates at the root of the nose, into the two angular veins. From the nasal arch, the frontal is continued downwards by the side of the root ofthe nose, under the name of the angular vein; it then passes beneath the zygomatic mus- cles and becomes the facial vein, and descends along the anterior border ofthe masseter muscle, crossing the body ofthe lower jaw, by the side of the facial artery, to the submaxillary gland, and from thence to the inter- nal jugular vein in which it terminates. The branches which the facial vein receives in its course are, the supra- orbital, which joins the frontal vein ; the dorsal veins of the nose which terminate in the nasal arch ; the ophthalmic, which communicates with the angular vein ; the palpebral and nasal, which open into the angular vein; a considerable trunk, the alveolar, which returns the blood from the spheno-maxillary fossa, from the infra-orbital, palatine, vidian, and spheno- palatine veins, and joins the facial beneath the zygomatic process of the superior maxillary bone, and the veins corresponding with the branches ofthe facial artery. The Internal maxillary vein receives the branches from the zygomatic and pterygoid fossae; these are so numerous and communicate so freely as to constitute a pterygoid plexus. Passing backwards behind the neck of the lower jaw, the internal maxillary joins with the temporal vein, and the common trunk resulting from this union constitutes the temporo-maxillary vein. The Temporal vein commences on the vertex of the head by a plexiform network which is continuous with the frontal, the temporal, auricular, and occipital veins. The ramifications of this plexus form an anterior and a pos- terior branch which unite immediately above the zygoma ; the trunk is here joined by another large vein, the middle temporal, winch collects the blood from the temporal muscle, and around the outer segment ofthe orbit, and pierces the temporal fascia near the root of the zygoma. The temporal vein then descends between the meatus auditorius externus and the con- dyle ofthe lower jaw, and unites with the internal maxillary vein, to form the temporo-maxillary. The Temporo-maxillary vein formed by the union of the temporal and internal maxillary, passes downwards in the substance of the parotid gland to its low7er border, where it becomes the external jugular vein. It receives in its course the anterior auricular, masseteric, transverse facial, and paro- tid veins, and near its termination is joined by the posterior auricular vein. The Posterior auricular vein communicates with the plexus upon the vertex of the head, and descends behind the ear to the temporo-maxillary vein, immediately before that vessel merges in the external jugular. It receives in its course the veins from the external ear and the stylo-mastoid vein. The Occipital vein commencing posteriorly in the plexus of the vertex ofthe head, follows the direction of the occipital artery, and passing deeply beneath the muscles of the back part ofthe neck, terminates in the internal jugular vein. This vein communicates with the lateral sinus by means of a large branch which passes through the mastoid foramen, the mastoid vein, VEINS OF THE DIPLOE. The diploe of the bones of the head is furnished in the adult with irregu- lar sinuses which are formed by a continuation of the internal coat of the 29' w 338 SINUSES OF THE DURA MATER. veins into the osseous canals in which they are lodged. At the middle period of life these sinuses are confined to the particular bones ; but in old age, after the ossification ofthe sutures, they may be traced from one bone to the next. They receive their blood from the capillaries supplying the cellular structure of the diploe, and terminate externally in the veins of the pericranium, and internally in the veins and sinuses of the dura mater. These veins are separated from the bony walls of the canals by a thin layer of medulla. CEREBRAL AND CEREBELLAR VEINS. The cerebral veins are remarkable for the absence of valves, and for the extreme tenuity of their coats. They may be arranged into the superficial, and deep or ventricular veins. The Superficial cerebral veins are situated on the surface of the hemi- spheres, lying in the grooves formed by the convexities of the convolutions. They are named from the position which they may chance to occupy upon the surface of this organ, either superior or inferior, internal or external, anterior or posterior. The Superior cerebral veins, seven or eight in number on each side, pass obliquely forwards, and terminate in the superior longitudinal sinus, in the opposite direction to the course of the stream of blood in the sinus. The Deep or Ventricular veins commence within the lateral ventricles by the veins of the corpora striata and those of the choroid plexus, which unite to form the two venae Galeni. The Vena Galeni pass backwards in the structure of the velum interpo- situm; and escaping through the fissure of Bichat, terminate in the straight sinus. The Cerebellar veins are disposed, like those of the cerebrum, on the surface of the lobes of the cerebellum ; they are situated some upon the superior, and some upon the inferior surface, while others occupy the borders of the organ. They terminate in the lateral and petrosal sinuses. SINUSES OF THE DURA MATER. The sinuses of the dura mater are irregular channels, formed by the splitting of the layers of that membrane, and lined upon their inner surface by a continuation of the internal coat of the veins. They may be divided into two groups:—1. Those situated at the upper and back part of the skull. 2. The sinuses at the base of the skull. The former are, the Superior longitudinal sinus, Inferior longitudinal sinus, Straight sinus, Occipital sinuses, Lateral sinuses. The Superior longitudinal sinus is situated in the attached margin of the falx cerebri, and extends along the middle line of the arch of the skull, from the foramen caecum in the frontal, to the inner tuberosity of the occi- pital bone, where it divides into the two lateral sinuses. It is triangular in form, is small in front, and increases gradually in size as it passes backwards; it receives the superior cerebral veins, which open into it obliquely, numerous small veins from the diploe, and near the posterior LATERAL SINUSES. 339 Fig. 162* extremity of the sagittal suture the parietal veins, from the peri- cranium and scalp. Examined in its interior, it presents numer- ous transverse fibrous bands (tra- becular), the chordae Willisii, which are stretched across its inferior angle; and some small white granular masses, the glan- dulae Pacchioni; the oblique openings of the cerebral veins, with their valve-like margin, are also seen on the walls of the sinus. The termination of the supe- rior longitudinal sinus in the two lateral sinuses forms a considera- ble dilatation, into which the straight sinus opens from the front, and the occipital sinuses from below. This dilatation is named the torcular Herophili,\ and is the point of communication of six sinuses, the superior longitudinal, two lateral, two occipital, and the straight. The Inferior longitudinal sinus is situated in the free margin of the falx cerebri; it is cylindrical in form, and extends from near the crista galli to the anterior border of the tentorium, where it terminates in the straight sinus. It receives in its course several veins from the falx. The Straight or fourth sinus is the sinus of the tentorium ; it is situated at the line of union of the falx with the tentorium ; is prismoid in form, and extends across the tentorium, from the termination of the inferior lon- gitudinal sinus to the torcular Herophili. It receives the venae Galeni, the cerebral veins from the inferior part of the posterior lobes, and the superior cerebellar veins. The Occipital sinuses are two canals of small size, situated in the at- tached border of the falx cerebelli; they commence by several small veins around the foramen magnum, and terminate by separate openings in the torcular Herophili. They not unfrequently communicate with the termi- nation of the lateral sinuses. The Lateral sinuses, commencing at the torcular Herophili, pass hori- zontally outwards, in the attached margin ofthe tentorium, and then curve downwards and inwards along the base of the petrous portion of the tem- poral bone, at each side, to the foramina lacera posteriora, where they ter- minate in the internal jugular veins. Each sinus rests in its course on the transverse groove of the occipital bone, posterior inferior angle of the parietal, mastoid portion of the temporal, and again on the occipital bone. They receive the cerebral veins from the inferior surface of the posterior * The sinuses ofthe upper and back part of the skull. 1. The superior longitudinal sinus. 2, 2. The cerebral veins opening into the sinus from behind forwards. 3. The falx cerebri. 4. The inferior longitudinal sinus. 5. The straight or fourth sinus. 6. The vense Galeni. 7. The torcular Herophili. 8. The two lateral sinuses, with the occipital sinuses between them. 9. The termination of the inferior petrosal sinus of one side. 10. The dilatations corresponding with the jugular fossae. 11. The internal jugular veins. + Torcular (a press), from a supposition entertained by the older anatomists that the columns of blood, coming in different directions, compressed each other at this point. 340 SUPERIOR PETROSAL SINUSES. Fig. 163.* lobes, the inferior cerebellar veins, the superior petrosal sinuses, the mas- toid, and posterior condyloid veins, and at their termination, the inferior petrosal sinuses. These sinuses are often unequal in size, the right being larger than the left. The sinuses of the base of the skull are the— Cavernous, Inferior petrosal, Circular, Superior petrosal, Transverse. The Cavernous sinuses are named from presenting a structure similar to that of the corpus cavernosum penis. They are situated on each side of the sella turcica, receiving, anteriorly, the ophthalmic veins through the sphenoidal fissures, and terminating posteriorly in the inferior petrosal sinuses. In the internal wall of each cavernous sinus is the internal carotid artery, accompanied by several filaments of the carotid plexus, and crossed by the sixth nerve ; and, in its external w-all, the third, fourth, and oph- thalmic nerves. These structures are separated from the blood flowing through the sinus, by the tubular lining membrane. The cerebral veins from the under surface of the anterior lobes open into the cavernous sinuses. They communicate by means of the ophthalmic with the facial veins, by the circular sinus with each other, and by the superior petrosal with the lateral sinuses. The Inferior petrosal sinuses are the con- tinuations of the cavernous sinuses back- wards along the lower border of the petrous portion of the temporal bone at each side of the base of the skull, to the foramina lacera posteriora, where they terminate with the lateral sinuses in the commencement of the internal jugular veins. The Circular sinus (sinus of Ridley) is situated in the sella turcica, surrounding the pituitary gland, and communicating on each side with the cavernous sinus. The poste- rior segment is larger than the anterior. The Superior petrosal sinuses pass ob- liquely backwards along the attached border ofthe tentorium, on the upper margin ofthe petrous portion of the temporal bone, and establish a communication between the ca- vernous and lateral sinus at each side. They receive one or two cerebral veins from the inferior part of the middle lobes, and a cerebellar vein from the anterior border of the cerebellum. Near the extremity of the petrous bone these sinuses cross the oval aperture which transmits the fifth nerve. * The sinuses ofthe base ofthe skull. 1. The ophthalmic veins. 2. The cavernous sinus of one side. 3. The circular sinus ; the figure occupies the position of the pituitary gland in the sella turcica. 4. The inferior petrosal sinus. 5. The transverse or ante- rior occipital sinus. 6. The superior petrosal sinus. 7. The internal jugular vein. 8. The foramen magnum. 9. The occipital sinuses. 10. The torcular Herophili. 11, 11. The lateral sinuses. VEINS OF THE NECK. 341 The Transverse sinus (basilar, anterior occipital) passes transversely across the basilar process of the occipital bone, forming a communication between the two inferior petrosal sinuses. Sometimes there are two si- nuses in this situation. VEINS OF THE NECK. The veins of the neck which return the blood from the head are the— External jugular, Anterior j ugular, Internal jugular, Vertebral. The External jugular vein is formed by the union ofthe posterior auri- cular vein with the temporo-maxillary, and commences at the lower bor- der of the parotid gland, in front of the sterno-mastoid muscle. It de- scends the neck in the direction of a line drawn from the angle of the lower jaw to the middle of the clavicle, crosses the sterno-mastoid, and terminates, near the posterior and inferior attachment of that muscle, in the subclavian vein. In its course downwards it lies upon the anterior lamella of the deep cervical fascia, which separates it from the sterno- mastoid muscle, and is covered in by the platysma myoides and superfi- cial fascia. At the root of the neck it pierces the deep cervical fascia ; it is accompanied, for the upper half of its course, by the auricularis magnus nerve. The branches which it receives are the occipital cutaneous and posterior cervical cutaneous, and, near its termination, the supra and pos- terior scapular. The external jugular vein is very variable in size, and is occasionally replaced by two veins. In the parotid gland it receives a large commu- nicating branch from the internal jugular vein. The Anterior jugular vein is a trunk of variable size, which collects the blood from the integument and superficial structures on the fore part of the neck. It passes downwards along the anterior border of the sterno- mastoid muscle, and opens into the subclavian vein, near the termination of the external jugular. The two veins communicate with each other, and with the external and internal jugular vein. The Internal jugular vein, formed by the convergence ofthe lateral and inferior petrosal sinus, commences at the foramen lacerum posterius on each side of the base of the skull, and descends the side of the neck, lying, in the first instance, to the outer side of the internal carotid, and then upon the outer side of the common carotid artery to the root of the neck, where it unites with the subclavian, and constitutes the vena inno- minata. At its commencement, the internal jugular vein is posterior and external to the internal carotid artery, and the eighth and ninth pairs ot nerves ; lower down, the vein and artery are on the same plane, the glosso- pharyngeal and hypoglossal nerves passing forwards between them, the pneumogastric being between and behind in the same sheath, and the nervus accessorius crossing obliquely behind the vein. The Branches which the internal jugular receives in its course are, the facial, the lingual, the inferior pharyngeal, the occipital, and the superior and inferior thyroid veins. The Vertebral vein descends by the side of the vertebral artery in the canal formed by the foramina in the transverse processes of the cervical 29* 342 VEINS OF THE UPPER EXTREMITY. vertebrae, and terminates at the root of the neck in the commencement of the vena innominata. In the lower part of the vertebral canal it frequently divides into two branches, one of which advances forwards, while the other passes through the foramen in the transverse process of the seventh cervical vertebra, before opening into the vena innominata. The Branches which it receives in its course are the posterior condyloid vein, muscular branches, the cervical meningo-rachidian veins, and near its termination, the superficial and deep cervical veins. The Inferior thyroid veins, two, and frequently more in number, are situated one on each side of the trachea, and receive the venous blood from the thyroid gland. They communicate with each other, and with the superior thyroid veins, and form a plexus upon the front of the trachea. The right vein terminates in the right vena innominata, just at its union with the superior cava, and the left in the left vena innominata. VEINS OF THE UPPER EXTREMITY. The veins of the upper extremity are the deep and superficial. The deep veins accompany the branches and trunks of the arteries, and consti- tute their vena comites. The venae comites of the radial and ulnar arte- ries are enclosed in the same sheath with those vessels, and terminate at the bend of the elbow in the brachial veins. The brachial venae comites are situated one on each side of the artery, and open into the axillary vein; the axillary becomes the subclavian, and the subclavian unites with the internal jugular to form the vena innominata. The Superficial veins of the fore-arm are the— Anterior ulnar vein, Posterior ulnar vein, Basilic vein, Radial vein, Cephalic vein, Median vein, Median basilic, Median cephalic. The Anterior ulnar vein collects the venous blood from the inner border of the hand, and from the vein of the little finger, vena salvatella, and ascends the inner side of the fore-arm to the bend of the elbow, where it becomes the basilic vein. The Posterior ulnar vein, irregular in size, and frequently absent, commences upon the inner bor- der and posterior aspect of the hand, and ascend- ing the fore-arm, terminates in front of the inner condyle, in the anterior ulnar vein. The Basilic vein (/SatfiXixos, royal, or principal) ascends from the common ulnar vein formed by the two preceding, along the inner side of the upper arm, and near its middle pierces the fascia; it then passes upwards to the axilla, and becomes the axillary vein. * The veins of the fore-arm and bend of the elbow. 1. The radial vein. 2. The cephalic vein. 3. The anterior ulnar vein. 4. The posterior ulnar vein. 5 The trunk formed by their union. 6. The basilic vein, piercing the deep fascia at 7. 9 A com- AXILLARY AND SUBCLAVIAN VEINS. 343 The Radial vein commences in the large vein of the thumb, on the outer and posterior aspect of the hand, and ascends along the outer bor- der of the fore-arm to the bend of the elbow, where it becomes the cepha- lic vein. The Cephalic vein (xspaXr,, the head) ascends along the outer side of the arm to its upper third ; it then enters the groove between the pectora- lis major and deltoid muscle, where it is in relation with the descending branch of the thoracico-acromialis artery, and terminates beneath the cla- vicle in the subclavian vein. A large communicating branch sometimes crosses the clavicle between the external jugular and this vein, which gives it the appearance of being derived directly from the head—hence its appellation. The Median vein is intermediate in position between the anterior ulnar and radial vein ; it collects the blood from the anterior aspect of the fore- arm, communicating with the two preceding. At the bend of the elbow it receives a branch from the deep veins, and divides into two branches, the median cephalic and median basilic. The Median cephalic vein, generally the smaller of the two, passes obliquely outwards, in the groove between the biceps and supinator longus, to join the cephalic vein. The branches of the external cutaneous nerve pass behind it. The Median basilic vein passes obliquely inwards, in the groove be- tween the biceps and pronator radii teres, and terminates in the basilic vein. This vein is crossed by one or two filaments of the internal cuta- neous nerve, and is separated from the brachial artery by the aponeurotic slip given off by the tendon of the biceps. AXILLARY VEIN. The axillary vein is formed by the union of the venae comites of the brachial artery with the basilic vein. It lies in front ofthe artery, receives numerous branches from the collateral veins of the branches of the axillary artery; and at the lower border of the first rib becomes the subclavian vein. SUBCLAVIAN VEIN. The subclavian vein crosses over the first rib and beneath the clavicle, and unites with the internal jugular vein to form the vena innominata. It lies at first in front of the subclavian artery, and then in front of the sca- lenus anticus, which separates it from that vessel. The phrenic and pneumogastric nerves pass between the artery and vein. The veins open- ing into the subclavian are the cephalic below the clavicle, and the external and anterior jugulars above; occasionally some small veins from the neighbouring parts also terminate in it. municating branch between the deep veins of the fore-arm and the upper part of the median vein. 10. The median cephalic vein. 11. The median basilic. 12. A slight convexity of the deep fascia, formed by the brachial artery 13. The process of fascia, derived from the tendon of the biceps, which separates the median basilic vein from th» hn^hial arterv 14. The external cutaneous nerve, piercing the deep fascia, and vidhng nto tranches, which pass behind the median cephalic vein. 15 The in- terna cutaneous nerve, dividing into branches, which pass in front of the median basi- Hc vein 16. The intercosto-humeral cutaneous nerve. 17. The spiral cutaneous nerve, a branch of the musculo-spiral. 344 FEMORAL VEIN — VEINS OF THE TRUNK. VEINS OF THE LOWER EXTREMITY. The veins of the lower extremity are the deep and superficial. The deep veins accompany the branches of the arteries in pairs, and form the venae comites of the anterior and posterior tibial and peroneal arteries. These veins unite in the popliteal region to form a single vein of large size, the popliteal, which successively becomes in its course the femoral and the external iliac vein. POPLITEAL VEIN. The popliteal vein ascends through the popliteal region, lying, in the first instance, directly upon the artery, and then getting somewhat to its outer side. It receives several muscular and articular branches, and the external saphenous vein. The valves in this vein are four or five in number. FEMORAL VEIN. The femoral vein, passing through the opening in the adductor magnus muscle, ascends the thigh in the sheath of the femoral artery, and entering the pelvis beneath Poupart's ligament, becomes the external iliac vein. In the lower part of its course it is situated upon the outer side of the artery ; it then becomes placed behind that vessel, and, at Poupart's liga- ment, lies to its inner side. It receives the muscular veins, and the pro- funda, and, through the saphenous opening, the internal saphenous vein. The valves in this vein are four or five in number. The Profunda vein is formed by the convergence ofthe numerous small veins which accompany the branches of the artery ; it is a vein of large size, lying in front of the profunda artery, and it terminates in the femoral at about an inch and a half below7 Poupart's ligament. The Superficial veins are the external or short, and the internal or long saphenous. The External saphenous vein collects the blood from the outer side of the foot and leg. It passes behind the outer ankle, ascends along the posterior aspect of the leg, lying in the groove betwreen the two bellies of the gastrocnemius muscle, and pierces the deep fascia in the popliteal region to join the popliteal vein. It receives several cutaneous branches in the popliteal region before passing through the deep fascia, and is ac- companied in its course by the external saphenous nerve. The Internal saphenous vein commences upon the dorsum and inner side of the foot. It ascends in front of the inner ankle, and along the inner side of the leg; it then passes behind the inner condyle of the femur and along the inner side of the thigh to the saphenous opening, where it pierces the sheath of the femoral vessels, and terminates in the femoral vein, at about one inch and a half below Poupart's ligament. It receives in its course the cutaneous veins of the leg and thigh, and communicates freely with the deep veins. At the saphenous opening it is joined by the superficial epigastric and circumflexa ilii veins, and by the external pudic. The situation of this vein in the thigh is not unfre- quently occupied by two or even three trunks of nearly equal size. VEINS OF THE TRUNK. The veins ofthe trunk maybe divided into, 1. The superior vena cava, with its formative branches. 2. The inferior vena cava, with its formative SUPERIOR AND INFERIOR VENjE CAV.E. 345 branches. 3. The azygos veins. 4. The vertebral and spinal veins. 5. The cardiac veins. 6. The portal vein. 7. The pulmonary veins. SUPERIOR VENA CAVA, WITH ITS FORMATIVE BRANCHES. Vena Innominata. The Vena Innominata are two large trunks, formed by the union of the internal jugular and subclavian vein, at each side of the root of the neck. The Right vena innominata, about an inch and a quarter in length, lies superficially and externally to the arteria innominata, and descends almost vertically to unite with its fellow of the opposite side in the formation of the superior cava. At the junction of the jugular and subclavian veins it receives from behind the ductus lymphaticus dexter, and lower down it has opening into it the right vertebral, right internal mammary, and right inferior thyroid vein. The Left vena innominata, considerably longer than the right, extends almost horizontally across the roots of the three great arteries arising from the arch of the aorta, to the right side of the mediastinum, where it unites with the right vena innominata, to constitute the superior cava. It is in relation in front with the left sterno-clavicular articulation and the first piece of the sternum. At its commencement it receives the tho- racic duct which opens into it from behind, and in its course is joined by the left vertebral, left inferior thyroid, left mammary, and by the superior intercostal vein. It also receives some small veins from the mediastinum and thymus gland. There are no valves in the venae innominatae. SUPERIOR VENA CAVA. The superior cava is a short trunk about three inches in length, formed by the junction of the two venae innominatae. It descends perpendicularly on the right side of the mediastinum, and entering the pericardium termi- nates in the upper part of the right auricle. It is in relation in front with the thoracic fascia, which separates it from the thymus gland, and with the pericardium ; behind with the right pulmo- nary artery, and right superior pulmonary vein ; internally with the ascend- ing aorta; externally with the right phrenic nerve, and right lung. Im- mediately before entering the pericardium it receives the vena azygos major. INFERIOR VENA CAVA, WITH ITS FORMATIVE BRANCHES. Iliac Veins. The External iliac vein lies to the inner side of the corresponding artery at the os pubis ; but gradually gets behind it as it passes upwards along the brim of the pelvis, and it terminates opposite the sacro-iliac symphysis by uniting with the internal iliac, to form the common iliac vein. Imme- diately above Poupart's ligament it receives the epigastric and circumflexa ilii veins; it has no valves. 346 INFERIOR VENA CAVA. Fig. 165* The Internal iliac vein is formed by vessels which correspond with the branches of the in- ternal iliac artery; it receives the returning blood from the gluteal, ischiatic, internal pudic, and obturator veins, externally to the pelvis; and from the vesical and uterine plexuses within the pelvis. The vein lies to the inner side of the internal iliac artery, and terminates by uniting with the external iliac vein, to form the common iliac. The Vesical and prostatic plexus is an im- portant plexus of veins which surrounds the neck and base of the bladder and prostate gland, and receives its blood from the great dorsal vein of the penis, and from the veins of the external organs of generation. It is retain- ed in connection with the sides of the bladder by a reflexion of the pelvic fascia. The Uterine plexus is situated around the vagina, and upon the sides of the uterus, be- tween the two layers of the broad ligaments. The veins forming the vesical and uterine plexus are peculiarly subject to the production of phlebolites. The Common iliac veins are formed by the union of the external and internal iliac vein on each side of the pelvis. The right com- mon iliac, shorter than the left, ascends ob- liquely behind the corresponding artery; and upon the intervertebral substance between the fourth and fifth lumbar vertebrae, unites with the vein ofthe opposite side, to form the inferior cava. The left common iliac, longer and more oblique than the right, ascends behind, and a little internally to the corresponding artery, and passes beneath the right com- mon iliac artery, near its origin, to unite with the right vein in the forma- tion ofthe inferior vena cava. The right common iliac vein has no branch opening into it; the left receives the vena sacra media. These veins have no valves. INFERIOR VENA CAVA. The inferior vena cava is formed by the union ofthe two common iliac veins, upon the intervertebral substance between the fourth and fifth lum- * The veins of the trunk and neck. 1. The superior vena cava. 2. The left vena innominata. 3. The right vena innominata. 4. The right subclavian vein. 5. The internal jugular vein. 6. The external jugular. 7. The anterior jugular. 8. The infe- rior vena cava. 9. The external iliac vein. 10. The internal iliac vein. 11. The com- mon iliac veins; the small vein between these is the vena sacra media. 12, 12. Lum- bar veins. 13. The right spermatic vein. 14. The left spermatic, opening into the left renal vein. 15. The right renal vein. 16. The trunk of the hepatic veins. 17. The greater vena azygos, commencing inferiorly in the lumbar veins. 18. The lesser vena azygos, also commencing in the lumbar veins. 19. A branch of communication with the left renal vein. 20. The termination of the lesser in the greater vena azygos. 21, The superior intercostal vein; communicating inferiorly with the lesser vena azygos, and terminating superiorly in the left vena innominata. INFERIOR VENA CAVA. 347 bar vertebra. It ascends along the front of the vertebral column, on the right side of the abdominal aorta, and passing through the fissure in the posterior border of the liver and the quadrilateral opening in the tendinous centre of the diaphragm, terminates in the inferior and posterior part of the right auricle. There are no valves in this vein. It is in relation from below upwards, in front with the mesentery, trans- verse duodenum, portal vein, pancreas, and liver, which latter nearly and sometimes completely surrounds it; behind it rests on the vertebral column and right crus of the diaphragm, from which it is separated by the right renal and right lumbar arteries; to the right it has the peritoneum and sympathetic nerve ; and to the left the aorta. The Branches which the inferior cava receives in its course, are the— Lumbar, Right spermatic, Renal, Supra-renal, Phrenic, Hepatic. The Lumbar veins, three or four in number on each side, collect the venous blood from the muscles and integument of the loins, and from the spinal veins: the left are longer than the right on account of the position of the vena cava. The Right spermatic vein is formed by the two veins which return the blood from the venous plexus situated in the spermatic cord. These veins follow the course of the spermatic artery, and unite to form the single trunk which opens into the inferior vena cava. The left spermatic vein terminates in the left renal vein. The Ovarian veins represent the spermatic veins ofthe male, and collect the venous blood from the ovaries, round ligaments, and Fallopian tubes, and communicate with the uterine sinuses. They terminate as in the male. The Renal or emulgent veins return the blood from the kidneys; their branches are situated in front of the divisions of the renal arteries, and the left opens into the vena cava somewhat higher than the right. The left is longer than the right in consequence of the position of the vena cava, and crosses the aorta immediately below the origin of the superior mesen- teric artery. It receives the left spermatic vein, w7hich terminates in it at right angles: hence the more frequent occurrence of varicocele on the left than on the right side. The Supra-renal veins terminate partly in the renal veins, and partly in the inferior vena cava. The Phrenic veins return the blood from the ramifications of the phrenic arteries; they open into the inferior cava. The Hepatic veins form two principal trunks and numerous smaller veins which open into the inferior cava, while that vessel is situated in the pos- terior border of the liver. The hepatic veins commence in the liver by minute venules, the intralobular veins, in the centre of each lobule ; these pour their blood into larger vessels, the sublobular veins ; and the sublo- bular veins constitute, by their convergence and union, the hepatic trunks, which terminate in the inferior vena cava. 348 VERTEBRAL AND SPINAL VEINS. AZYGOS VEINS. The azygos veins (fig. 165) form a system of communication between the superior and inferior vena cava, and serve to return the blood from that part of the trunk of the body in which those vessels are deficient, on account of their connexion with the heart. This system consists of three vessels, the Vena azygos major, Vena azygos minor, Superior intercostal vein. The Vena azygos major commences in the lumbar region by a commu- nication with the lumbar veins; sometimes it is joined by a branch directly from the inferior vena cava, or by one from the renal vein. It passes through the aortic opening in the diaphragm, and ascends along the right side of the vertebral column to the third dorsal vertebra, where it arches forwards over the right bronchus, and terminates in the superior cava. It receives all the intercostal veins of the right side, the vena azygos minor, and the bronchial veins. The Vena azygos minor commences in the lumbar region, on the left side, by a communication with the lumbar or renal veins. It passes be- neath the border of the diaphragm, and, ascending along the left side of the vertebral column, crosses the fifth or sixth dorsal vertebra to open into the vena azygos major. It receives the six or seven lower intercostal veins of the left side. The azygos veins have no valves. The Superior intercostal vein is the trunk formed by the union of the five or six upper intercostal veins of the left side. It communicates below with the vena azygos minor, and ascends to terminate in the left vena innominata. VERTEBRAL AND SPINAL VEINS. The numerous venous plexuses of the vertebral column and spinal cord may be arranged into three groups:— Dorsi-spinal, Meningo-rachidian, Medulli-spinal, The Dorsi-spinal veins form a plexus around the spinous, transverse and articular processes, and arches of the vertebrae. They receive the return- ing blood from the dorsal muscles and surrounding structures, and trans- mit it, in part to the meningo-rachidian, and in part to the vertebral, in- tercostal, lumbar, and sacral veins. The Meningo-rachidian veins are situated between the theca vertebralis and the vertebrae. They communicate freely with each other by means of a complicated plexus. In front they form two longitudinal trunks, (longitudinal spinal sinuses,) which extend the whole length ofthe column on each side of the posterior common ligament, and are joined on the body of each vertebra by transverse trunks, which pass beneath the liga- ment, and receive the large basi-vertebral veins from the interior of each vertebra. The meningo-rachidian veins communicate superiorly through the anterior condyloid foramina with the internal jugulars; in the neck they pour their blood into the vertebral veins; in the thorax, into the in- PORTAL SYSTEM. 349 tercostals; and m the loins and pelvis into the lumbar and sacral veins, the communications being established through the intervertebral foramina. The Medulli-spinal veins are situated between the pia mater and arach- noid ; they communicate freely with each other to form plexuses, and they send branches through the intervertebral foramina with each of the spinal nerves, to join the veins of the trunk. CARDIAC VEINS. The veins returning the blood from the substance of the heart, are the— Great cardiac vein, Posterior cardiac veins, Anterior cardiac veins, Venae Thebesii. The Great cardiac vein (coronary) commences at the apex of the heart, and ascends along the anterior ventricular groove to the base of the ven- tricles ; it then curves around the left auriculo-ventricular groove to the posterior part of the heart, where it terminates in the right auricle. It re- ceives in its course the left cardiac veins from the left auricle and ventricle, and the posterior cardiac veins from the posterior ventricular groove. The Posterior cardiac vein, frequently two in number, commences also at the apex of the heart, and ascends along the posterior ventricular groove, to terminate in the great cardiac vein. It receives the veins from the pos- terior aspect of the two ventricles. The Anterior cardiac veins collect the blood from the anterior surface ofthe right ventricle ; one larger than the rest runs along the right border of the heart and joins the trunk formed by these veins, which curves around the right auriculo-ventricular groove, to terminate in the great cardiac vein near its entrance into the right auricle. The Vena Thebesii are numerous minute venules which convey the venous blood directly from the substance of the heart into its four cavities. Their existence is denied by some anatomists. PORTAL SYSTEM. The portal system is composed of four large veins which return the blood from the chylopoietic viscera; they are the— Inferior mesenteric vein, Superior mesenteric vein, Splenic vein, Gastric veins. The Inferior mesenteric vein receives its blood from the rectum by means of the haemorrhoidal veins, and from the sigmoid flexure and de- scending colon, and ascends behind the transverse duodenum and pan- creas to terminate in the splenic vein. Its haemorrhoidal branches inos- culate with branches of the internal iliac vein, and thus establish a com- munication betw-een the portal and general venous system. The Superior mesenteric vein is formed by branches which collect the venous blood from the capillaries of the superior mesenteric artery; they 30 350 VENA PORTJS. constitute by their junction a large trunk, which ascends by the side ofthe corresponding artery, crosses the transverse duodenum, and unites behind the pancreas with the splenic in the formation ofthe portal vein. The Splenic vein commences in the structure of the spleen, 'and quits that organ by several large veins: it is larger than the splenic artery, and Fig. 166.* perfectly straight in its course. It passes horizontally inwards behind the pancreas, and terminates near its greater end by uniting with the superior mesenteric, and forming the portal vein. It receives in its course the gastric and pancreatic veins, and near its termination the inferior mesen- teric vein. The Gastric veins correspond with the gastric, gastro-epiploic, and vasa brevia arteries, and terminate in the splenic vein. The Vena porta:, formed by the union of the splenic and superior mesenteric vein behind the pancreas, ascends through the right border of the lesser omentum to the transverse fissure of the liver, where it divides into tw7o branches, one for each lateral lobe. In the right border of the lesser omentum it is situated behind and between the hepatic artery and ductus communis choledochus, and is surrounded by the hepatic plexus of nerves and lymphatics. At the transverse fissure each primary branch divides into numerous secondary branches, which ramify through the * The portal vein. 1. The inferior mesenteric vein ; it is traced by means of dotted -ines behind the pancreas (2) to terminate in the splenic vein (3). 4. The spleen. 5, Gastric veins, opening into the splenic vein. 6. The superior mesenteric vein. 7. The descending portion ofthe duodenum. 8. Its transverse portion, which is crossed by the superior mesenteric vein and by a part of the trunk of the superior mesenteric artery, 9. The portal vein. 10. The hepatic artery. 11. The ductus communis choledochus. 12. The division ofthe duct and vessels at the transverse fissure of the liver. 13. The cystic duct leading to the gall bladder. ON THE LYMPHATICS. 351 portal canals, and give off vaginal and interlobular veins, and the latter terminate in the lobular venous plexus of the lobules of the liver. The portal vein within the liver receives the venous blood from the capillaries of the hepatic artery. PULMONARY VEINS. The pulmonary veins, four in number, return the arterial blood from the lungs to the left auricle of the heart; they differ from the veins in general, in the area of their cylinders being very little larger than that of the corresponding arteries, and in accompanying singly each branch of the pulmonary artery. They commence in the capillaries upon the parietes ofthe intercellular passages and air-cells, and unite to form a single trunk for each lobe. The vein of the middle lobe of the right lung unites with the superior vein, so as to form the two trunks which open into the left auricle. Sometimes they remain separate, and then there are three pul- monary veins on the right side. The right pulmonary veins pass behind the superior vena cava to the left auricle, and the left behind the pulmo- nary artery; they both pierce the pericardium. Within the lung the branches ofthe pulmonary veins are behind the bronchial tubes, and those ofthe pulmonary artery in front; but at the root ofthe lungs the veins are in front, next the arteries, and then the bronchi. There are no valves in the pulmonary veins. CHAPTER VIII. ON THE LYMPHATICS. The lymphatic vessels, or absorbents, have received their double appel- lation from certain phenomena which they present; the former name being derivable from the appearance of the limpid fluid (lympha, water) which they convey; and the latter from their supposed property of absorbing foreign substances into the system. They are minute, delicate, and trans- parent vessels, remarkable for their general uniformity of size, for a knotted appearance which is due to the presence of numerous valves, for the fre- quent dichotomous divisions which occur in their course, and for their division into several branches immediately before entering a gland. Their office is to collect the products of digestion and the detrita of nutrition, and convey them into the venous circulation near the heart. Lymphatic vessels commence in a delicate network which is distributed on the cutaneous surface of the body, on the various surfaces of organs and throughout their internal structure ; and from this network the lym- phatic vessels proceed, nearly in straight lines, in a direction towards the root of the neck. In their course they are intercepted by numerous small, spheroid, or oblong, or flattened bodies, lymphatic glands. The lymphatic- vessels entering these glands are termed vasa inferenfia or afferentia, and those which quit them, vasa eferentia. The vasa inferenfia vary in num- ber from two to six, they divide at the distance of a few lines from the gland into several smaller vessels, and enter it by one of the flattened sur- 352 GENERAL ANATOMY OF LYMPHATICS. faces.* The vasa efferentia escape from the gland on the opposite, but not unfrequently on the same surface ; they consist, like the vasa inferenfia at their junction with the gland, of several small vessels which unite after a course of a few lines to form from one to three trunks, often twice as large as the vasa inferentia. Lymphatic vessels admit of a threefold division, into superficial, deep, and lacteals. The superficial lymphatic vessels, on the surface of the body, follow the course of the veins, and pierce the deep fascia in conve- nient situations, to join the deep lymphatics. On the surface of organs they converge to the nearest lymphatic trunks. The superficial lymphatic glands are placed in the most protected situations of the superficial fascia, as in the hollow of the ham and groin in the lower extremity, and on the inner side of the arm in the upper extremity. The deep lymphatics, fewer in number and somewhat larger than the superficial vessels, accompany the deeper veins; those from the lower parts of the body converging to the numerous glands seated around the iliac veins and inferior vena cava, and terminating in a large trunk situated on the vertebral column, the thoracic duct. From the upper part of the trunk of the body on the left side, and from the left side of the head and neck, they also proceed to the thoracic duct. Those on the right side of the head and neck, right upper extremity, and right side of the thorax, form a distinct duct which terminates at the point of junction of the sub- clavian with the internal jugular vein on the right side of the root of the neck. The lacteals are the lymphatic vessels of the small intestines; they have received their distinctive appellation from conveying the milk-like product of digestion, the chyle, to the great centre of the lymphatic system, the thoracic duct. They are situated in the mesentery, and pass through the numerous mesenteric glands in their course. Lymphatic vessels are very generally distributed through the animal tissues; there are, nevertheless, certain structures in which they have never been detected ; for example, the brain and spinal cord, the eye, bones, cartilages, tendons, the membranes of the ovum, the umbilical cord, and the placenta. The anastomoses between these vessels are less frequent than between arteries and veins; they are effected by means of vessels of equal size with the vessels which they connect, and no increase of calibre results from their junction. The lymphatic vessels are smallest in the neck, larger in the upper extremities, and larger still in the lower limbs. For the purpose of effecting the movement of their fluids in a proper direction, lymphatic vessels are furnished with valves, and it is to these that the appearance of constrictions around the cylinders ofthe vessels, at short distances, is due. Like the valves of veins, the valves of lymphatic vessels are each composed of two semilunar flaps attached by their convex Dorder to the sides of the vessel and free by their concave border. This is the general character of the valves, but, as in veins, there are exceptions in their form and disposition; sometimes one flap is so small as to be merely rudimentary, while the other is large in proportion ; sometimes the flap runs all the way round the tube, leaving a central aperture which can only be closed by a contractile power in the valve itself; and some- * See Mr. Lane's article on the " Lymphatic System," in the Cyclopaedia of Anatomy and Physiology. LYMPHATICS OF THE HEAD AND NECK. 353 times instead of being circular the aperture is elliptical, and the arrange- ment of the flaps like that of the ileo-ccecal valve." These peculiarities are most frequently met with at and near the anastomoses of the lymphatic vessels. The valves occur most numerously near the lymphatic glands; next in frequency they are found in the neck and upper extremities, where the vessels are small, and least numerously in the lower limbs, where the lymphatics are larger. In the thoracic duct an interspace of two or three inches frequently occurs between the valves. Connected with the presence of valves in the lymphatic vessels, are two lateral dilatations or pouches, analogous to the valvular sinuses of veins. These sinuses are situated on the cardiac side of the valves; they receive the valves when the latter are thrown back by the current of the lymph ; and when reflux occurs, they become distended with a body of fluid which makes pressure on the flaps. These pouch-like dilatations and the constrictions corresponding with the line of attachment of the convex borders of the flaps are the cause of the knotted appearance of distended lymphatic vessels. Like arteries and veins, lymphatic vessels are composed of three coats, external, middle, and internal. The external coat is areolo-fibrous, like that of blood-vessels; it is thin, but very strong, and serves to connect the vessel to surrounding tissues, at the same time that it forms a protec- tive covering. The middle coat is thin and elastic, and consists of a layer of longitudinal fibres analogous to those of the innermost layer of the middle coat of arteries and veins. Some few circular fibres may be seen externally to these in the larger lymphatic vessels. The internal coat is inelastic and more liable to rupture than the other coats. It is a serous layer continuous with the lining membrane of the veins, and invested by an epithelium. The valves are composed of a very thin layer of fibrous tissue, coated on its two surfaces by epithelium. The lymphatic glands (conglobate, absorbent) are small oval and some- what flattened or rounded bodies, composed of a plexus of minute lym- phatic vessels, associated with a plexus of blood-vessels, and enclosed in a thin capsule of areolar tissue. When examined on the surface, they are seen to have a lobulated appearance, while the face of a section is cellular, from the division of the numberless convolutions which are formed by the lymphatic vessels within its substance. The colour of the glands is a pale pink, excepting those ofthe lungs, the bronchial glands, which in the adult are more or less mottled with black, and are sometimes filled with a black pigment. Lymphatic glands are larger in the young subject than in the adult, and are smallest in old age ; they, as well as their ves- sels, are supplied with arteries, veins and nerves, like other structures. I shall describe the lymphatic vessels and glands according to the arrangement adopted for the veins, commencing with those of the head and neck, and proceeding next to those of the upper extremity, lower ex- tremity, and trunk. LYMPHATICS OF THE HEAD AND NECK. The Superficial lymphatic glands of the head and face are small, few in number, and isolated ; they are, the occipital, w7hich are situated near the origin of the occipito-frontalis muscle; posterior auricular, behind the ear; parotid, in the parotid gland; zygomatic, in the zygomatic fossa; * Mr. Lane, loc. cit. 30* x 354 LYMPHATICS OF THE UPPER EXTREMITY. buccal, upon the buccinator muscle ; and submaxillary, beneath the mar- gin of the low7er jaw. There are no deep lymphatic glands within the cranium. The Superficial cervical lymphatic glands are few in number and small; they are situated in the course of the external jugular vein, between the sterno-mastoid and trapezius muscles, at the root of the neck, and about the larynx. The Deep cervical glands (glandulae concatenatae) are numerous and of large size ; they are situated around the internal jugular vein and sheath of the carotid arteries, by the side of the pharynx, oesophagus, and trachea, and extend from the base of the skull to the root of the neck, where they are in communication with the lymphatic vessels and glands of the thorax. The Superficial lymphatic vessels of the head and face are disposed in three groups; occipital, which take the course of the occipital vein to the occipital and deep cervical glands; temporal, w7hich follow7 the branches of the temporal vein to the parotid and deep cervical glands; and facial, which accompany the facial vein to the submaxillary lymphatic glands. The Deep lymphatic vessels of the head are the meningeal and cerebral, the former are situated in connexion with the meningeal veins, and escape through foramina at the base of the skull, to join the deep cervical glands. The cerebral lymphatics, according to Fohmann, are situated on the sur- face of the pia mater, none having as yet been discovered in the substance of the brain. They pass most probably through the foramina at the base of the skull, to terminate in the deep cervical glands. The Deep lymphatic vessels of the face proceed from the nasal fossae, mouth, and pharynx, and terminate in the submaxillary and deep cervical glands. The Superficial and deep cervical lymphatic vessels accompany the jugular veins, passing from gland to gland, and at the root of the neck communicate with the thoracic lymphatic vessels, and terminate, on the right side, in the ductus lymphaticus dexter, and, on the left, in the tho- racic duct, near its termination. LYMPHATICS OF THE UPPER EXTREMITY. The uperficial lymphatic glands of the arm are not more than four or five in number, and of very small size. One or two are situated near the median basilic and cephalic veins, at the bend of the elbow ; and one or two near the basilic vein, on the inner side ofthe upper arm, immediately above the elbow. The Deep glands in the fore-arm are excessively small and infrequent; tw7o or three may generally be found in the course of the radial and ulnar vessels. In the upper arm there is a chain of small glands, accompanying the brachial artery. The Axillary glands are numerous and of large size. Some are closely adherent to the vessels, others are dispersed in the loose areolar tissue of the axilla, and a small chain may be observed extending along the lower border ofthe pectoralis major to the mammary gland. Two or three sub- clavian glands are situated beneath the clavicle, and serve as the medium of communication between the axillary and deep cervical lymphatic glands. The Superficial lymphatic vessels of the upper extremity commence upon the fingers and take their course along the fore-arm to the bend of the LYMPHATICS OF THE LOWER EXTREMITY. 355 elbow. The greater part reach their destination by passing along the dorsa* surface of the fingers, wrist, and fore-arm, and then curving around the borders of the latter; but some few are met with in the palm of the hand, which take the direction of the median vein. At the bend of the elbow the lymphatics arrange themselves into tw7o groups ; an internal and larger group, which communicates with a gland situated just above the inner condyle, and then accompanies the basilic vein upwards to the axilla to enter the axillary glands; and a small group which follows the course of the cephalic vein. Several of the vessels of this group cross the biceps muscle at its upper part to enter the axillary glands, while the remainder, two or three in number, ascend with the cephalic vein in the interspace of the deltoid and pectoralis major; these latter usually join a small gland in this space, and then cross the pectoralis minor muscle to become continu- ous with the subclavian lymphatics. Besides the lymphatic vessels of the arm, the axillary glands receive those from the integument of the chest, its anterior, posterior, and lateral aspect, and the lymphatics ofthe mammary gland. The Deep lymphatics accompany the vessels of the upper extremity, and communicate occasionally with the superficial lymphatics. They 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 ductus lym- phaticus dexter. LYMPHATICS OF THE LOWER EXTREMITY. The Superficial lymphatic glands of the lower extremity are those of the groin, the inguinal; and one or two situated in the superficial fascia ofthe posterior aspect ofthe thigh, just above the popliteal region. The Inguinal glands are divisible intotw7o groups; a superior group of small size, situated along the course of Poupart's ligament, and receiving the lymphatic vessels from the parietes of the abdomen, gluteal region, peri- neum, and genital organs; and an inferior group of larger glands clustered around the internal saphenous vein near its termination, and receiving the superficial lymphatic vessels from the lower extremity. The Deep lymphatic glands are the anterior tibial, popliteal, deep ingui- nal, gluteal, and ischiatic. The Anterior tibial is generally a single gland, placed on the interosse- ous membrane, by the side of the anterior tibial artery in the upper part of its course. The Popliteal glands, four or five in number and small, are embedded in the loose areolar tissue and fat of the popliteal space. The Deep inguinal glands, less numerous and smaller than the superficial, are situated near the femoral vessels in the groin, beneath the fascia lata. The Gluteal and ischiatic glands are placed near the vessels of that name, above and below the pyriformis muscle at the great ischiatic foramen. The Superficial lymphatic vessels are divisible into two groups, internal and external; the internal and principal group, commencing on the dorsum and inner side of the foot, ascend the leg by the side of the internal sa- phenous vein, and passing behind the inner condyle of the femur, follow the direction 'of that vein to the groin, where they join the saphenous group of superficial inguinal glands. The greater part of the efferent vessels from 356 LYMPHATICS OF THE TRUNK. these glands pierce the cribriform fascia of the saphenous opening and the sheath of the femoral vessels, to join the lymphatic gland situated in the femoral ring, which serves to establish a communication between the lym- phatics of the lower extremity and those of the trunk. The other efferent vessels pierce the fascia lata to join the deep glands. The vessels which pass upwards from the outer side of the dorsum of the foot, ascend along the outer side ofthe leg, and curve inwards just below the knee, to unite with the lymphatics of the inner side of the thigh. The external group consists of a few lymphatic vessels which commence on the outer side of the foot and posterior part of the ankle, and accompany the external saphenous vein to the popliteal region, where they enter the popliteal glands. The Deep lymphatic vessels accompany the deep veins, and communi- cate with the various glands in their course. After joining the deep in- guinal glands they pass beneath Poupart's ligament, to communicate with the numerous glands situated around the iliac vessels. The deep lym- phatics ofthe gluteal region follow the course ofthe branches of the gluteal and ischiatic arteries. The former join the glands situated on the upper border of the pyriformis muscle, and the latter, after communicating with the lymphatics of the thigh, enter the ischiatic glands. LYMPHATICS OF THE TRUNK. The lymphatics of the trunk may be arranged under three heads, super- ficial, deep, and visceral. The Superficial lymphatic vessels of the upper half of the trunk pass upwards and outwards on each side, and converge, some to the axillary glands, and others to the glands at the root ofthe neck. The lymphatics from the mammary glands follow the lower border of the pectoralis major, communicating, by means of a chain of lymphatic glands, with the axil- lary glands. The superficial lymphatic vessels of the lower half of the trunk, ofthe gluteal region, perineum, and external organs of generation, converge to the superior group of superficial inguinal glands. Some small glands are situated on each side of the dorsal vein of the penis, near the suspensory ligament; from these, as from the superficial lymphatics, the efferent vessels pass into the superior group of superficial inguinal glands. The Deep lymphatic glands of the thorax are the intercostal, internal mammary, anterior mediastinal, and posterior mediastinal. The Intercostal glands are of small size, and are situated on each side ofthe vertebral column, near the articulations ofthe heads ofthe ribs, and in the course ofthe intercostal arteries. The Internal mammary glands, also very small, are placed in the inter- costal spaces, by the side of the internal mammary arteries. The Anterior mediastinal glands occupy the loose areolar tissue of the anterior mediastinum, resting some on the diaphragm, but the greater number on the large vessels at the root of the heart. The Posterior mediastinal glands are situated along the course of the aorta and oesophagus in the posterior mediastinum, and communicate above with the deep cervical glands, on each side with the intercostal and below with the abdominal glands. The Deep lymphatic vessels of the thorax are the intercostal, internal mammary, and diaphragmatic. LYMPHATICS OF THE VISCERA. 357 The Intercostal lymphatic vessels follow the course of the arteries of the same name; and reaching the vertebral column curve downwards, to ter- minate in the thoracic duct. The Internal mammary lymphatics commence in the parieties of the abdomen, communicating with the epigastric lymphatics. They ascend by the side of the internal mammary vessels, being joined in their course by the anterior intercostals, and terminate at the root of the neck, on the right side in the tributaries of the ductus lymphaticus dexter, and on the left in the thoracic duct. The diaphragmatic lymphatics pursue the direc- tion of their corresponding veins, and terminate some in front in the in- ternal mammary vessels, and some behind, in the posterior mediastinal lymphatics. The Deep lymphatic glands ofthe abdomen are the lumbar glands; they are very numerous, and are seated around the common iliac vessels, the aorta and vena cava. The deep lymphatic glands of the pelvis are the external iliac, internal iliac and sacral. The External iliac are placed around the external iliac vessels, being in continuation by one extremity with the femoral lymphatics, and by the other with the lumbar glands. The Internal iliac glands are situated in the course of the internal iliac vessels, and the sacral glands are supported by the concave surface of the sacrum. The Deep lymphatic vessels are continued upwards from the thigh, be- neath Poupart's ligament, and along the external iliac vessels to the lum- bar glands, receiving in their course the epigastric, tircumflexa ilii, and ilio-lumbar lymphatic vessels. Those from the parietes of the pelvis, and from the gluteal, ischiatic, and obturator vessels, follow the course of the internal iliac arteries, and unite with the lumbar lymphatics. And the lumbar lymphatic vessels, after receiving all the lymphatics from the lower extremities, pelvis, and loins, terminate by several large trunks in the receptaculum chyli. LYMPHATICS OF THE VISCERA. The Lymphatic vessels ofthe lungs are of large size, and are distributed over every part of the surface, and through the texture of these organs ; they converge to the numerous glands situated around the bifurcation of the trachea and roots of the lungs, the bronchial glands. Some of these glands of small size, may be traced in connexion with the bronchial tubes for some distance into the lungs. The efferent vessels from the bronchial glands unite with the tracheal and oesophageal glands, and terminate prin- cipally in the thoracic duct at the root of the neck, and partly in the duc- tus lymphaticus dexter. The bronchial glands, in the adult, present a variable tint of brown, and in old age a deep black colour. In infancy they have none of this pigment, and are not to be distinguished from lym- phatic glands in other situations. The Lymphatic vessels of the heart originate in the subserous areolar tissue of the surface, and in the deeper tissues of the organ, and follow the course of the vessels, principally, along the right border of the heart to the glands situated around the arch of the aorta and to the bronchia] 358 LYMPHATICS OF THE VISCERA. glands, w7hence they proceed to the root of the neck, and terminate in the thoracic duct. The Pericardiac and thymic lymphatic vessels proceed to join the ante- rior mediastinal and bronchial glands. The Lymphatic vessels of the liver are divisible into the deep and su- perficial. The former take their course through the portal canals, and through the right border of the lesser omentum, to the lymphatic glands situated in the course of the hepatic artery and along the lesser curve of the stomach. The superficial lymphatics are situated in the areolar struc- ture of the proper capsule, over the whole surface of the liver. Those of the convex surface are divided into two sets ;—1. Those which pass from before backwards ; 2. Those which advance from behind forwards. The former unite to form trunks, which enter between the folds of the lateral ligaments at the right and left extremities of the organ, and of the coronary ligament in the middle. Some of these pierce the diaphragm and join the posterior mediastinal glands; others converge to the lymphatic glands situated around the inferior cava. Those which pass from behind for- wards consist of two groups: one ascends between the folds of the broad ligament, and perforates the diaphragm, to terminate in the anterior medi- astinal glands; the other curves around the anterior margin of the liver to its concave surface, and from thence to the glands in the right border of the lesser omentum. The lymphatic vessels of the concave surface are variously distributed, according to their position ; those from the right lobe terminate in the lumbar glands; those from the gall-bladder, which are large and form a remarkable plexus, enter the glands in the right bor- der of the lesser omentum ; and those from the left lobe converge to the lymphatic glands situated along the lesser curve ofthe stomach. The Lymphatic glands of the spleen are situated around its hilus, and those of the pancreas in the course of the splenic vein. The lymphatic vessels of these organs pass through their respective glands, and join the aortic glands, previously to terminating in the thoracic duct. The Lymphatic glands ofthe stomach are of small size, and are situated along the lesser and greater curves of that organ. The lymphatic vessels, as in other viscera, are superficial and deep, the former originating in the subserous and the latter in the submucous tissue ; they pass from the sto- mach in four different directions: some ascend to the glands, situated along the lesser curve, others descend to those occupying the greater curve, a third set pass outwards to the splenic glands, and a fourth to the glands situated near the pylorus and to the aortic glands. The Lymphatic glands of the small intestine are situated between the layers of the mesentery, in the meshes formed by the superior mesenteric artery, and are thence named mesenteric glands. These glands are most numerous and largest, superiorly, near the duodenum; and, inferiorly, near the termination ofthe ileum. The Lymphatic vessels of the small intestines are of two kinds: those of the structure of the intestines, which run upon its surface pre- viously to entering the mesenteric glands ; and those w-hich commence in the villi, in the substance of the mucous membrane, and are named lacteals. The Lacteals, according to Henle, commence in the centre of each vil- 'us as a caecal tubulus, which opens into a fine network, situated in the THORACIC DUCT. 359 sub-mucous tissue. From this areolar netw-ork the lacteal vessels proceed to the mesenteric glands, and from thence to the thoracic duct, in which they terminate. The Lymphatic glands of the large intestines are situated along the at- tached margin of the intestine, in the meshes formed by the colic and haemorrhoidal arteries previously to their distribution. The lymphatic vessels take their course in two different directions; those of the caecum, ascending and transverse colon, after traversing their proper glands, pro- ceed to the mesenteric, and those of the descending colon and rectum to the lumbar glands. The Lymphatic vessels ofthe fcidney follow the direction of the blood- vessels to the lumbar glands situated around the aorta and inferior vena cava; those of the supra-renal capsules, which are very large and nume- rous, terminate in the real lymphatics. The Lymphatic vessels of the viscera of the pelvis terminate in the sacral and lumbar glands. The Lymphatic vessels of the testicle take the course of the spermatic cord in which they are of large size; they terminate in the lumbar glands. THORACIC DUCT. The thoracic duct* commences in the abdomen, by a considerable and somewhat triangular dilatation, the receptaculum chyli, which is situated on the front of the body of the second lumbar vertebra, behind and be- tween the aorta and inferior vena cava, and close to the tendon of the right crus of the diaphragm. From the upper part of the receptaculum chyli the thoracic duct ascends through the aortic opening of the dia- phragm, and along the front of the vertebral column, lying between the thoracic aorta and vena azygos, to the fourth dorsal vertebra. It then in- clines to the left side, passes behind the arch of the aorta, and ascends by the side of the oesophagus and behind the perpendicular portion of the left subclavian artery to the root of the neck opposite the seventh cervical vertebra, where it makes a sudden curve forwards and downwards, and terminates at the point of junction of the left subclavian with the left in- ternal jugular vein. The thoracic duct is equal in size to the diameter of a goose-quill at its commencement from the receptaculum chyli, diminishes considerably in diameter towards the middle of the posterior mediastinum, and again be- comes dilated near its termination. At about the middle of the thorax it frequently divides into two branches of equal size, which reunite after a short course ; and sometimes it gives off several branches, which assume a plexiform arrangement in this situation. Occasionally the thoracic duct bifurcates at the upper part of the thorax into two branches, one of which opens into the point of junction between the right subclavian and jugular veins, while the other proceeds to the normal termination of the duct on the left side. In rare instances the duct has been found to terminate in the vena azygos, which is its normal destination in some Mammalia. * The thoracic duct was discovered by Eustachius, in 1563, in the horse : he regarded it as a vein and called it the vena alba thoracis. The lacteals were first seen by Asel lius in 16->2 in the dog; and within the next ten years by Veslingius in man. 360 THORACIC DUCT. Fig. 167* The thoracic duct presents fewer valves in its course than lymphatic vessels generally ; at its termination it is provided with a pair of semilunar valves, which prevent the admission of venous blood into its cylinder. Branches.—The thoracic duct receives at its commencement four or five large lymphatic trunks, which unite to form the receptaculum chyli: it next receives the trunks of the lacteal vessels. Within the thorax it is joined by a large lymphatic trunk from the liver, and in its course through the posterior mediastinum, receives the lymphatic vessels both from the viscera and from the parietes of the thorax. At its curve forwards in the neck it is joined by the lymphatic trunks from the left side of the head and neck, left upper extremity, and from the upper part of the thorax, and thoracic viscera. The Ductus lymphaticus dexter is a short trunk which receives the lymphatic vessels from the right side ofthe head and neck, right upper extremity, right side of the thorax, right lung, and one or two branches from the liver, and terminates at the junction of the right subclavian with the right internal jugular vein, at the point where these veins unite to form the right vena innominata. It is provided at its termination with a pair of semilunar valves, which prevent the entrance of blood from the veins. * The course and termination ofthe thoracic duct. 1. The arch ofthe aorta. 2. The thoracic aorta. 3. The abdominal aorta; showing its principal branches divided near their origin. 4. The arteria innominata, dividing into the right carotid and right sub- clavian arteries. 5. The left carotid. 6. The left subclavian. 7. The superior cava, formed by the union of 8, the two venae innominatas; and these by the junction 9, of the internal jugular and subclavian vein at each side. 10. The greater vena azygos. 11. The termination of the lesser in the greater vena azygos. 12. The receptaculum chyli; several lymphatic trunks are seen opening into it. 13. The thoracic duct, divid- ing opposite the middle of the dorsal vertebrae into two branches which soon reunite; the course of the duct behind the arch of the aorta and left subclavian artery is shown by a dotted line. 14. The duct, making its turn at the root of the neck and receiving several lymphatic trunks previously to terminating in the posterior aspect of the junc- tion of the internal jugular and subclavian vein. 15. The termination of the trunk of the ductus lymphaticus dexter. ON THE NERVOUS SYSTEM. 361 CHAPTER IX. ON THE NERVOUS SYSTEM. The nervous system consists of a central organ, the cerebro-spinal centre or axis, and of numerous rounded and flattened white cords, the nerves, which are connected by one extremity with the cerebro-spinal centre, and by the other are distributed to all the textures of the body. The sympa- thetic system is an exception to this description; for in place of one it has many small centres which are called ganglia, and which communicate very freely with the cerebro-spinal axis and with its nerves. The cerebro-spinal axis consists of two portions, the brain, an organ of large size, situated within the skull, and the spinal cord, a lengthened portion of the nervous centre continuous with the brain and occupying the canal ofthe vertebral column. The most superficial examination of the brain, and spinal cord shows them to be composed of fibres, or rather fasciculi, which in some situations are ranged in a longitudinal direction, and in others are interlaced at va- rious angles by cross fibres. The fasciculi are connected and held together by a delicate areolar web, wnich forms the bond of support to the entire organ. It is also observed that the cerebro-spinal axis presents two sub- stances differing from each other in density and colour: a grey or cineri- tious or cortical substance, and a white or medullary substance. The grey substance forms a thin lamella over the entire surface of the convolu- tions of the cerebrum, and of the laminae of the cerebellum: hence it has been named cortical; but the grey substance is not confined to the surface ofthe brain, as this term would imply; it is likewise situated in the centre of the spinal cord its entire length, and may be thence traced through the medulla oblongata, crura cerebri, thalami optici, and corpora striata; it enters also into the composition of the locus perforatus, tuber cinereum, commissura mollis, pineal gland, pituitary gland, and corpora rhomboidea. Two kinds of grey substance are described by Rolando as existing in the spinal cord ; the one (substantia cinerea spongiosa vasculosa) is the ordi- nary grey matter of the cord, and the other (substantia cinerea gelatinosa) forms part of the posterior cornua. The former resembles in structure the grey matter of the brain, while the latter is composed of small bodies re- sembling the blood corpuscules ofthe frog. The fibres of the cerebro-spinal axis are arranged into two classes, di- verging and converging. The diverging fibres proceed from the medulla oblongata, and diverge to every part of the surface of the brain ; while the converging fibres commence at the surface and proceed inwards towards the centre, so as to connect the diverging fibres of opposite sides. In cer- tain parts of their course the diverging fibres are separated by the grey substance and increase in number so as to form a body of considerable size, which is called a ganglion. The position and mutual relations of these fibres and ganglia may be best explained by reference to the mode of development of the cerebro-spinal axis in animals and in man. The centre of the nervous system, in the lowest animals possessed of a 31 362 NERVOUS SYSTEM—DEVELOPMENT. lengthened axis, presents itself in the form of a double cord. A step higher in the animal scale, and knots or ganglia are developed on one ex- tremity of this cord; such is the most rudimentary condition of the brain in the lowest forms of vertebrata. In the lowest fishes the anterior ex- tremity of the double cord displays a succession of five pairs of ganglia. The higher fishes and amphibia appear to have a different disposition of these primitive ganglia. The first two have become fused into a single ganglion, and then follow7 only three pairs of symmetrical ganglia. But if the larger pair be unfolded, after being hardened in alcohol, it will then be seen that the whole number of ganglia exist, but that four have become concealed by a thin covering that has spread across them. This condition of the brain carries us upwards in the animal scale even to Mammalia; e. g., in the dog or cat we find, first, a single ganglion, the cerebellum; then three pairs following each other in succession; and if we unfold the middle pair, we shall be at once convinced that it is composed of two pairs of primitive ganglia concealed by an additional development. Again, it will be observed, that the primitive ganglia of opposite sides, at first separate and disjoined, become connected by means of transverse fibres of communication (commissures; commissura, a joining). The office of these commissures is the association in function of the two symmetrical portions. Hence we arrive at the general and important conclusion, that the brain, among the low7er animals, consists of primitive cords, primitive ganglia upon those cords, and commissures which connect the substance of adjoin- ing ganglia, and associate their functions. In the development of the cerebro-spinal axis in man, the earliest indi- cation of the spinal cord is presented under the form of a pair of minute longitudinal filaments placed side by side. Upon these, towards the an- terior extremity, five pairs of minute swellings are observed, not disposed in a straight line as in fishes, but curved upon each other so as to corres- pond with the direction of the future cranium. The posterior pair soon become cemented on the middle line, forming a single ganglion ; the se- cond pair also unite with each other; the third and fourth pairs, at first distinct, are speedily veiled by a lateral development, which arches back- wards and conceals them ; the anterior pair, at first very small, decrease in side, and become almost lost in the increased development of the pre- ceding pairs. We see here a chain of resemblances corresponding with the progressive development observed in the lower animals; the human brain is passing through the phases of improving development, which distinguish the lowest from the lower creatures: and we are naturally led to the same conclusion with regard to the architecture of the human brain that we were led to establish as the principle of development in the inferior creatures, namely, that it is composed of primitive cords, primitive ganglia upon those cords, commissures to connect those ganglia, and developments from those ganglia. In the adult, the primitive longitudinal cords have become cemented together, to form the spinal cord. But, at the upper extremity, they se- parate from each other under the name of crura cerebri. The first pair of ganglia, developed from the primitive cords, have grow7n into the cere- bellum; the second pair (the optic lobes of animals) have become the corpora quadrigemina of man. The third pair, the optic thalami, and the fourth, the corpora striata, are the basis of the hemispheres, w-hich, the GREY NERVE FIBRES. 363 merest lamina in the fish, have become the largest portion of the brain in man. And the fifth pair (olfactory lobes), so large in the lowest forms, have dwindled into the olfactory bulbs of man. The microscopic elements of the nervous system, are, white nerve- fibres, grey nerve-fibres, nerve-cells, and nerve-granules. 1. White nerve fibres are the chief con- stituent of the brain, the spinal cord, and the Fis- 168* cerebro-spinal nerves, and they also enter into the composition of the sympathetic nerve. They present some variety of size in different parts of the nervous system, measuring in the brain betw-een a^an and ,4050 °f an incn m diameter, and in the cerebro-spinal nerves be- tween 0500 and Woo °f an inch. As a general rule, the white nerve-fibres are largest in the nerves, smaller where they enter the cerebro- spinal mass, and smallest at their termination, centrally, in the grey substance of the surface of the brain, and, periphe- rally, in the tissues of the body. In structure, each white nerve-fibre is composed of a transparent and structureless cylindrical tubule or sheath (vagina medullaris), and of an axis-cylinder filled with an opalescent, colourless, oil-like fluid (neurine), which coagulates after death, and then resembles a white, opaque, and curd-like matter. The vagina medullaris possesses somewhat less than one-third the thickness of the entire fibre, and gives to the latter, when examined with the microscope, the aspect of a double cylinder,—an appearance which is characteristic of the white nerve-fibre. It is thickest in the fibres of the spinal nerves, and thinnest in those of the spinal cord, brain, and nerves of special sense. Hence in these latter, the sheath, when pressed or stretched, is apt to assume a varicose appearance, and the contained substance to accumulate in small separate masses. White nerve-fibres terminate, both at the surface of the body, in the various internal organs, and in the substance of the cerebro- spinal axis, by forming loops. 2. Grey Nerve fibres (fine nerve-fibres, gelatinous fibres, sympathetic fibres) are about one-half or one-third less in diameter (3750 to ssdo of an inch, Henle) than the white fibres. They are less transparent, have no appearance of being composed of a double cylinder, and their sheath is less easily distinguishable from its contents. In structure, they consist of a thin and finely granulated sheath, filled with granular substance, and, when collected into a fasciculus, have a yellowish grey tint. The grey nerve-fibres are abundant in, and are indeed the chief constituent of, the sympathetic system. They are also present in the cerebro-spinal nerves, and, most numerously, in the nerves of sensation. They take their origin from the nerve-cells of the grey substance of the brain and spinal cord, * Minute structure of nerve. 1. The mode of termination of white nerve-fibres in loops; three of these loops are simple, the fourth is convoluted. The latter is found in situations where an exalted degree of sensation exists. 2. A white nerve-fibre from the brain, showing the varicose appearance produced by traction or pressure. 3. A white nerve-fibre enlarged to show its structure,—namely, a tubular envelope, and a contained substance, neurine. 4. A nerve-cell, showing its composition of a granular- looking capsule and granular contents. 5. Its nucleus containing a nucleolus. 6. A nerve-cell from which several processes are given off. It contains, like the preceding, a nucleolated nucleus. 7. Nerve-granules. 364 NERVE CELLS—NERVE GRANULES. from those of the ganglia on the posterior roots of the cerebro-spinal nerves, and from the nerve-cells of the ganglia of the sympathetic system. 3. The Nerve-cells are spherical or oval, or polyhedral in shape, of a reddish grey colour, and between 3^ and T^SJi of an inch in diameter. Each cell is composed of a capsular sheath, and contains in its interior a reddish-grey granular substance, and one or more nuclei and nucleoli, the nucleus being attached to the internal surface of the sheath. The sheath of the nerve-cell is constructed of three layers, the outermost con- sisting of fine granular corpuscles, the middle of nucleated cells of an oblong figure, and the internal of concentric lamellae of delicate cylindrical filaments. Dispersed through the substance of the cell are a greater or less number of pigment-granules, some being in the interior, and some in the sheath. Nerve-cells are found in the grey substance of the brain and spinal cord, in the ganglia of the cerebro-spinal nerves, and in the sympathetic ganglia and nerves. The nerve-cells of the grey substance of the brain are often very irregular in shape, and they are also remarkable for their oftness and for the thinness of their sheath. It is the pigment-granules, contained in the nerve-cells and nerve-granules, that give the peculiar tint of colour to the grey and dark substance of the cerebro-spinal axis. In the grey substance of the brain the nerve-cells may be seen in various stages of progressive development; thus, near the periphery, they are minute, spherical or oval, nucleated cells dispersed through a matrix of granular substance; more deeply, the granular substance is collected around the cells, and forms an exterior coat; while, at a greater depth, the cells have attained the size and the laminated sheaths of the fully formed nerve-cells. Nerve-cells offer many peculiarities in respect of number and arrangement in different parts of the nervous system. From the periphery of the nerve-cells one or more delicate thread-like processes, between ^^^ and Tq^ou oi" an mcn m diameter, are given off. These are the origins of the grey nerve-fibres. 4. Nerve granules present the three forms of, minute homogeneous particles, aggregated particles, and nucleated corpuscles, varying in size between go1^ and lb^v of an inch in diameter. They serve as the bond of connexion between the fibres and cells of the brain and spinal cord, particularly in the grey substance; and enter also into the composition of the various ganglia. Like nerve-cells, nerve-granules contain, and have intermix rt with them, a variable number of pigment-granules. In thi construction of a nerve the nerve-fibres are collected into small fasciculi, each fasciculus being invested by a distinct neurilemma. These fasciculi, again, are collected into bundles, forming larger fasciculi, which have also a separate neurilemma; and a bundle of the larger fasciculi, enclosed in a sheath or neurilemma of white fibrous tissue, constitutes a nerve. The neurilemma of the smaller fasciculi is smooth and semitrans- parent, and remarkable for its satiny polish,—an appearance w7hich is due to the longitudinal arrangement of the undulating fasciculi of fibrous tissue of which it is composed. Another character which the smaller nervous fasciculi possess, is that of being crossed by oblique or transverse lines, which are produced, in all probability, by the wrinkling of the neurilemma. In the fasciculi of grey fibres the tendency to wrinkle exists in the lon- gitudinal direction, and the neurilemma is composed of an inner layer of circular filaments as well as an outer layer of the longitudinal filaments of fibrous tissue. CONSTRUCTION OF NERVES. 365 The nerve-fibres have no inosculations, but pursue an uninterrupted course from their central to their peripheral termination. In some instances they return after a short curve to the cerebro-spinal centre, as, for example, in the posterior part of the optic commissure, in the two roots of each spinal nerve, and in the loop formed between the descendens noni and the upper cervical nerves. In these cases, the fibres form a simple arch, both extremities of the arch maintaining a communication with the cerebro- spinal axis. In another instance, the direction of the curve is reversed, the centre of the arch being in the anterior part of the optic commissure, and the extremities in the retina. The communications which take place between nerves are termed plexuses. These plexuses are sometimes formed by the trunks of the nerves, as, the cervical, brachial, and lumbar; and sometimes by the fas- ciculi, as in the terminal plexuses at the periphery of the body and at the surface of the brain. The nerve-fibres in the spinal cord and central parts of the brain also form a close and plexiform interlacement with each other. In the construction of the larger plexuses there is a free interchange of fasciculi, and in the terminal plexuses a similar interchange of smaller fas- ciculi and primitive fibres. It is from the terminal plexuses that the nerve- fibres pass off to form their terminal loops. The general mode of termination of nerve-fibres is by loops. There exists, however, an exception to this rule in the instance of the Pacinian* corpuscles. These corpuscles are minute bodies, about a line in length, of an oval, oblong, or spheroidal shape, and smooth and glistening aspect, connected with the terminal nerve-fibres of the digital branches of the nerves distributed to the hands and feet. As many as two or three hun- dred are met with in a single hand. They are also found, but less nume- rously, on the terminal fibres of other sensitive nerves, and on the fibres of the sympathetic plexuses of the mesentery, of the meso-colon, and of the pancreas. They occur singly and in groups of twro or three, and are each connected with the nerve by means of a short pedicle which projects into the corpuscle, and forms a conical process in its interior. The Paci- nian corpuscle and its pedicle are composed of about fifty thin and mem- branous tunics, which are closely adherent in the latter, but are separated in the corpuscle by an albuminous fluid, and towards the free end of the corpuscle, the tunics are connected by imperfect septa. IJhe central tunic or capsule is also filled with fluid, and into this fluid th. ^.'is cylin- der of a primitive nervous fibril, derived from the nerve and a mtinued through the centre of the peduncle, is prolonged. According to Henle and Kblliker, this nervous fibril generally terminates in a small rounded enlargement; at other times it bifurcates and forms two rounded heads, and occasionally escapes from the corpuscle at its free end. Each of the tunics of the Pacinian body is composed of fibres which have a circular disposition on its external surface, and are arranged in a longitudinal direction within. It is these fibres which give to the corpuscle its glisten- inn- appearance. The Pacinian corpuscles are first perceptible during the sixth month of foetal life. On certain of the nerves of the body, for example, on the posterior roots of the cranial and spinal nerves, and particularly on the sympathetic, are situated enlargements w7hich are termed ganglia. Ganglia are greyish in * Discovered and described by Pacini in 1831; described more particularly in 1840, and by Henle and Kblliker in 1844. 31* 366 CLASSIFICATION OF NERVES. colour, are invested by a smooth membranous sheath, and are composed of the three essential constituents of the nervous system, namely, nerve- cells, nerve-fibres, and nerve-granules. The nerve-cells of ganglia are firm in structure, and have stronger investing sheaths than those of the brain. From the exterior of their sheaths, filaments of fibrous tissue are given off, which interlace with each other, and hold the cells together; and at the same time form an investing network around the entire gan- glion, the nerve-fibres passing into and out of the ganglion through the interstices of this network. Besides the sheath-filaments, certain of the nerve-cells give off grey fibres, while others are free. The nerve-fibres of ganglia are of the tw7o kinds met with in the rest of the nervous system. The white-fibres are derived from the cerebro-spinal axis, and enter the sympathetic through the so-called roots of that nerve, namely, its commu- nications with the spinal nerves. In the ganglia these white fibres sepa- rate, and either pass directly onwards between the nerve-cells (traversing fibres), or make a series of turns around them (winding fibres); in either case, they collect together after a plexiform course between the nerve-cells, and form fasciculi, which pass off as branches from the ganglion. The grey nerve-fibres originate from certain of the nerve-cells within the gan- glion as finely granular threads, and pass away in the form of fasciculi, with or without association of the white fibres, to be distributed to the various organs, or to traverse other ganglia previously to their distribution. The Nerve-granules occupy the interstices between the nerve-cells and the nerve-fibres, as in the cerebro-spinal mass. They are also continued with the nerve-fibres, into some of the nerves given off by the ganglia. Like the interstitial substance of the brain, the granular substance (gela- tinous substance) of ganglia has intermingled with it minute cells and pigment-granules. Nerves are divisible into two great classes; those which proceed di- rectly from the cerebro-spinal axis, the cranial and spinal nerves, and constitute the system of animal life; and those which originate from the sympathetic system, or system of organic life. The division of nerves# into cranial and spinal is purely arbitrary, and depends on the circumstance of the former passing through the foramina of the cranium, and the latter through those of the vertebral column. With respect to origin, all the cranial nerves, with' the exception of the first, [olfacrary,] proceed from the spinal cord, or from its immediate pro- longation into the brain. The spinal nerves arise by two roots; anterior, which proceeds from the anterior segment of the spinal cord, and possesses a motor function; and posterior, which is connected with the posterior segment, and bestow7s the faculty of sensation. The motor nerves of the cranium are shown by dissection to be continuous with the motor portion of the cord, and form one system with the motor roots of the spinal cord; while the nerves of' sensation, always excepting the ol- factory, are in like manner traced to the posterior segment of the cord, and form part of the system of sensation. To these two systems a third was added by Sir Charles Bell, the respiratory system, which consists of nerves associated in the function of respiration, and arising from the side of the upper part of the spinal cord in one continuous line, which he thence named the respiratory tract. The microscope has failed in making out any structural distinction between the anterior and posterior roots of the spinal nerves; but the latter are remarkable for the possession of a \ \ ORIGIN OF NERVES--BRAIN. 367 ganglion near their attachment with the cord. This ganglion is observed upon the posterior roots of all the spinal nerves, and also upon the corre- sponding root of the fifth cranial nerve, which is thence considered a spinal cranial nerve. Upon others of the cranial nerves a ganglion is found, which associates them in function with the nerves of sensation, and estab- lishes an analogy with the spinal nerves. According to Mr. Grainger, both roots of the spinal nerves, as well as of most of the cerebral, divide into tw-o sets of fibres upon entering the cord, one set being connected with the gray substance, while the other is continuous with the white or fibrous part of the cord. The former he considers to be the agents of the excito-motory system of Dr. Marshall Hall; and the latter, the communication with the brain and the medium for the transmission of sensation and volition. He has not been able to trace the fibres which enter the gray substance to their termination ; but he thinks it probable that the ultimate fibres of the posterior root join those of the anterior root; or, in the words of Dr. Marshall Hall's system, that the incident fibres (sensitive) are continuous with the reflex (motor). The connexion of a nerve with the cerebro-spinal axis is called, for convenience of description, its origin : this term must not, however, be taken literally, for each nerve is developed in the precise situation w7hich it occupies in the body, and with the same relations that it possesses in after life. Indeed, w7e not unfrequently meet with instances, in anenceph- alous foetuses, where the nerves are beautifully and completely formed, while the brain and spinal cord are wanting. The word " origin" must therefore be considered as a relict of the darkness of preceding ages, when the cerebro-spinal axis was looked upon as the tree from which the nerves pushed forth as branches. In their distribution, the spinal nerves for the most part follow the course of the arteries, particularly in the limbs, where they lie almost constantly to the outer side and superficially to the vessels, as if for the purpose of receiving the first intimation of danger and of com- municating it to the muscles, that the latter may instantly remove the arte- ries from impending injury. The Sympathetic system consists of numerous ganglia, of communicat- ing branches passing between the ganglia, of others passing between the ganglia and the cerebro-spinal axis, and of branches of distribution which are remarkable for their frequent and plexiform communications. The sympathetic nerves also differ from other nerves in their colour, which is of a grayish pearly tint. The capillary vessels of nerves are very minute. They run parallel with the nervous fasciculi, and every here and there are connected by transverse communications, so as to give rise to a net-work composed of oblong meshes very similar to the capillary system of muscles. The nervous system may be divided for convenience of description into 1. The brain. 2. The spinal cord. 3. The cranial nerves. 4. The spinal nerves. 5. The sympathetic system. THE BRAIN. The brain is a collective term which signifies those parts of the nervous system exclusive of the nerves themselves, which are contained within the cranium; they are the cerebrum, cerebellum, and medulla oblongata.* * The weight of the human brain, according to Soemmering, is 2ft. ^3. to 3ft. I3". 7$. 368 MEMBRANES OF THE ENCEPHALON. These are invested and protected by the membranes of the brain, and the whole together constitute the encephalon (iv xecpa'hri, within the head). MEMBRANES OF THE ENCEPHALON. Dissection.—To examine the encephalon with its membranes, the upper part of the skull must be removed, by sawing through the external table and breaking the internal table with the chisel and hammer. After the calvarium has been loosened all round, it will require a considerable de- gree of force to tear the bone away from the dura mater. This adhesion is particularly firm at the sutures, where the dura mater is continuous with a membranous layer interposed between the edges of the bones; in other situations, the connexion results from numerous vessels which permeate the inner table of the skull. The adhesion subsisting between the dura mater and bone is greater in the young subject and in old persons than in the adult. On being torn away, the internal table will present numerous deeply grooved and ramified channels, corresponding with the branches of the arteria meningea media. Along the middle line will be seen a groove corresponding with the superior longitudinal sinus, and on either side may be frequently observed some small fossae, corresponding with the Pacchi- onian bodies. The membranes ofthe encephalon are the dura mater, arachnoid mem- brane, and pia mater. The Dura mater* is the firm, whitish or greyish layer which is brought into view7 when the calvarium is removed. It is a strong fibrous membrane, somewhat laminated in texture, and composed of white fibrous tissue. Lining the interior of the cranium, it serves as the internal periosteum of that cavity; it is prolonged also into the spinal column, under the name of theca vertebralis, but is not adherent to the bones in that canal as in the cranium. From the internal surface of the dura mater, processes are di- rected inwards for the support and protection of parts of the brain; while from its exterior, other processes are prolonged outwards to form sheaths for the nerves as they quit the skull and spinal column. Its external sur- face is rough and fibrous, and corresponds with the internal table of the skull. The internal surface is smooth, and lined by the thin varnish-like lamella of the arachnoid membrane. The latter is a serous membrane. Hence the dura mater becomes a fibro-serous membrane, being composed of its own proper fibrous structure, and the serous layer derived from the arachnoid. There are two other instances of fibro-serous membrane in the body, formed in the same way, namely, the pericardium and tunica albu- ginea of the testicle. On the external surface of the dura mater the branches of the middle meningeal artery may be seen ramifying; and in the middle line is a de- pressed groove, formed by the subsidence ofthe upper wall ofthe superior longitudinal sinus. If the sinus be opened along its course, it will be found to be a triangular channel, crossed at its lowrer angle by numerous white bands, called chordae Willisii ;f granular bodies are also occasion- ally seen in its interior, these are glandulae Pacchioni. * So named from a supposition that it was the source of all the fibrous membranes of the body. + Willis lived in the seventeenth century; he was a great defender of the opinions of Harvey. DURA MATER. 369 The Glandula Pacchioni* are small, round, whitish granulations, oc- curring singly or m clusters, and forming small groups of various size along the margin of the longitudinal fissure of the cerebrum, and more particu- larly near the summit of the latter. These bodies would seem to be of morbid origin; they are absent in infancy, increase in numbers in adult life, and are abundant in the aged. They are generally associated with opacity of the arachnoid around their bases, but in some instances are wanting even in the adult. They have their point of attachment in the pia mater, from which they seem to spring, carrying with them the arachnoid membrane, and then, in proportion to their size, producing various effects upon contiguous parts. For example, when small, they remain free or constitute a bond of adhesion between the visceral and parietal layer of the arachnoid ; when of larger size they produce absorption ofthe dura mater, and as the degree of absorption is greater or less, they protrude through that membrane, and form depressions on the inner surface of the cranium, or simply render the dura mater thin and cribriform. Sometimes they cause absorption ofthe wall of the longitudinal sinus, and projecting into its cavity, give rise to the granulations described in connexion with that channel. If the student cut through one side of the dura mater, in the direction of his incision through the skull, and turn it upwards towards the middle line, he will observe the smooth internal surface of this membrane. He will perceive also the large veins of the hemispheres filled with dark blood, and passing from behind forwards to open into the superior longitudinal sinus; and the firm connexion, by means of these veins and the Pacchi- onian bodies, between the opposed surfaces of the arachnoid membrane. If he separate these adhesions with his scalpel, he will see a vertical layer of dura mater descending between the hemispheres; and if he draw one side of the brain a little outwards, he will be enabled to perceive the ex- tent of the process of membrane, which is called the falx cerebri. The processes of dura mater which are sent imvards towards the interior ofthe skull, are the falx cerebri, tentorium cerebelli, and falx cerebelli. The Falx cerebri (falx, a sickle), so named from its sickle-like appear- ance, narrow in front, broad behind, and forming a sharp curved edge below, is attached in front to the crista galli process of the ethmoid bone, and behind to the tentorium cerebelli. The Tentorium cerebelli (tentorium, a tent) is a roof of dura mater, thrown across the cerebellum and attached at each side to the margin of the petrous portion of the temporal bone ; behind, to the transverse ridge of the occipital bone, which lodges the lateral sinuses ; and to the clinoid processes in front. It supports the posterior lobes of the cerebrum and prevents their pressuref on the cerebellum, leaving only a small opening anteriorly, for the transmission of the crura cerebri. The Falx cerebelli is a small process, generally double, attached to the vertical ridge of the occipital bone beneath the lateral sinus, and to the tentorium. It is received into the indentation between the two hemi- spheres of the cerebellum. The layers ofthe dura mater separate in several situations, so as to form * These bodies are incorrectly described as conglobate glands by Pacchioni, in an epistolatory dissertation, " He Glandulis conglobatis Dura? Meningis indeque ortis Lym- phaticis ad Piam Matrem prodnctis," published at Rome, in 1705. + In leaping animals, as the feline and canine genera, the tentorium forms a bony tent Y 370 ARACHNOID MEMBRANE. irregular channels which receive the venous blood. These are the sinuses of the dura mater, which have been described at page 338. The student cannot see the tentorium and falx cerebelli until the brain is removed ; but he should consider the attachments of the former on the dried skull, for he will have to incise it in the removal ofthe brain. He should now proceed to that operation, for which purpose the dura mater is to be incised all round, on a level with the section through the skull, and the scissors are to be carried deeply between the hemispheres of the brain in front, to cut through the anterior part of the falx ; then draw the dura mater backwards, and leave it hanging by its attachment to the ten- torium. Raise the anterior lobes ofthe brain carefully with the hand, and lift the olfactory bulbs from the cribriform fossae with the handle of the scalpel. Then cut across the two optic nerves and internal carotid arte- ries. Next divide the infundibulum and third nerves, and carry the knife along the margin ofthe petrous bone at each side, so as to divide the ten- torium near its attachment. Cut across the fourth, fifth, sixth, seventh, and eighth nerves in succession with a sharp knife, and pass the scalpel as far down as possible into the vertebral canal, to sever the spinal cord, cut- ting first to one side and then to the other, in order to divide the vertebral arteries and first cervical nerves. Then let him press the cerebellum gently upwards with the fingers of the right hand, the hemispheres being supported with the left, and the brain will roll into his hand. The Arteries of the dura mater are the anterior meningeal from the ethmoidal, ophthalmic, and internal carotid. The middle meningeal and meningea parva from the internal maxillary. The inferior meningeal from the ascending pharyngeal and occipital arteries; and the posterior menin- geal from the vertebral. Its JVerves are derived from the nervi molles and vertebral plexus of the sympathetic, from the Casserian ganglion, the ophthalmic nerve, and sometimes from the fourth. The branches from the two latter are given off while those nerves are situated by the side of the sella turcica; they are recurrent, and pass backwards between the layers ofthe tentorium, to the lining membrane of the lateral sinus. Purkinje describes a sympa- thetic plexus of considerable size, as being situated around the vena Galeni at its entrance into the fourth sinus. The filaments from this plexus are distributed to the tentorium. Arachnoid Membrane. The Arachnoid (dga-xyy s^°?> hke a spider's web), so named from its extreme tenuity, is the serous membrane of the cerebro-spinal centre; and, like other serous membranes, a shut sac. It envelopes the brain and spinal cord (visceral layer) and is reflected upon the inner surface of the dura mater (parietal layer), giving to that membrane its serous investment. On the upper surface of the hemispheres the arachnoid is transparent, but may be demonstrated as it passes across the sulci from one convolu- tion to another by injecting, with a blow-pipe, a stream of air beneath it. At the base of the brain the membrane is opalescent and thicker than in other situations, and more easily demonstrable from the circumstance of stretching across the interval between the middle lobes of the hemispheres. The space which is included between this layer of membrane and those parts of the base of the brain which are bounded by the optic commissure PIA MATER. 371 and fissures of Sylvius in front, and the pons Varolii behind, is termed the anterior sub-arachnoidean space. Another space formed in a similar manner, between the under part of the cerebellum and the medulla oblon- gata, is the posterior sub-arachnoidean space ; and a third space, situated over the corpora quadrigemina, may be termed the superior sub-arach- noidean space. These spaces communicate freely with each other, the anterior and posterior across the crura cerebelli, the anterior and the supe- rior around the crura cerebri, and the latter and the posterior across the cerebellum in the course of the vermiform processes. They communicate also with a still larger space formed by the loose disposition of the arach- noid around the spinal cord, the spinal sub-arachnoidean space. The whole of these spaces, with the lesser spaces between the convolutions of the hemispheres, constitute one large and continuous cavity which is filled with a limpid, serous secretion, the sub-arachnoidean fluid * a fluid which is necessary to the maintenance and protection of the cerebro-spinal mass. The quantity of the sub-arachnoidean fluid is determined by the relative size of the cerebro-spinal axis and that of the containing cavity, and is consequently very variable. It is smaller in youth than in old age, and in the adult has been estimated at about tw7o ounces. The visceral layer ofthe arachnoid is connected to the pia mater by a delicate areolar tissue, which in the sub-arachnoidean spaces is loose and filamentous. The serous secretion of the true cavity of the arachnoid is very small in quan- tity as compared with the sub-arachnoidean fluid. The arachnoid does not enter into the ventricles of the brain, as imagined by Biehat, but is reflected inwards upon the venae Galeni for a short dis- tance only, and returns upon those vessels to the dura mater of the tento- rium. It surrounds the nerves as they originate from the brain, and forms a sheath around them to their point of exit from the skull. It is then re- flected back upon the inner surface ofthe dura mater. According to Mr. Rainey,f vessels of considerable size, but few in number; and branches of cranial nerves are found in the arachnoid. He also describes, in this membrane, numberless plexuses and ganglia, which he considers to be analogous to those of the sympathetic nerve. The fibres proceeding from this source are distributed on the arteries and nerves of the cerebro-spinal axis, but particularly on the former. Pia Mater. The Pia mater is a vascular membrane composed of innumerable ves- sels held together by a thin layer of areolar tissue. It invests the whole surface of the brain, dipping into the sulci between the convolutions, and forming a fold in its interior called velum interpositum. It also forms folds in other situations, as in the third and fourth ventricles, and in the longi- tudinal fissures ofthe spinal cord. This membrane differs very strikingly in its structure in different parts of the cerebro-spinal axis. Thus, on the surface of the cerebrum, in contact with the soft grey matter of the brain, it is extremely vascular, forming re- markable loops of anastomoses in the interspaces of the convolutions, and • The presence of a «erous fluid beneath the arachnoid has given rise to the conjec- ture that a M.b-arachnoid serous membrane may exist in that situation. Such a suppo sition is quite unnecessary to explain the production of the secretion, since the pia ■nator is fully adequate to that function | Medico-Chirurgical Transactions, vol. 29. 372 CEREBRUM. distributing multitudes of minute straight vessels to the grey substance. In the substantia perforata, again, and locus perforatus, it gives off tufts of small arteries, which pierce the white matter to reach the grey substance in the interior. But upon the crura cerebri, pons Varolii, and spinal cord, its vascular character seems almost lost. It has become a dense fibrous membrane, difficult to tear off, and forming the proper sheath of the spinal cord. The pia mater is the nutrient membrane of the brain, and derives its blood from the internal carotid and vertebral arteries. Its Nerves are the minute filaments of the sympathetic, which accom- pany the branches of the arteries. CEREBRUM. The Cerebrum presents on its surface a number of slightly convex ele- vations, the convolutions, (gyri) which are separated from each other by sulci of various depth.* It is divided superiorly into two hemispheres by the great longitudinal fissure, which lodges the falx cerebri, and marks the original development of the brain by two symmetrical halves. Each hemisphere, upon its under surface, admits of a division into three lobes, anterior, middle, and posterior. The anterior lobe rests upon the roof of the orbit, and is separated from the middle by the fissure of Sylvius.f The middle lobe is received into the middle fossae of the base of the skull, and is separated from the posterior by a slight impression produced by the ridge of the petrous bone. The posterior lobe is supported by the tentorium. If the upper part of one hemisphere, at about one-third from its summit, be removed with a scalpel, a centre of white substance will be observed, surrounded by a narrow border of grey, which follows the line ofthe sulci and convolutions, and presents a zigzag form. This section from exhibit- ing the largest surface of medullary substance demonstrable in a single hemisphere is called centrum ovale minus ; it is spotted by numerous small red points (puncta vasculosa) which are produced by the escape of blood from the cut ends of minute arteries and veins. Now separate carefully the two hemispheres of the cerebrum, and a broad band of white substance (corpus callosum) will be seen to connect them ; it will be seen also that the surface of the hemisphere where it comes in contact with the corpus callosum is bounded by a large convolution (gyrus fornicatus) which lies horizontally on that body, and maybe traced forwards and backwards to the base of the brain, terminating by each ex- tremity at the fissure of Sylvius. The sulcus between this convolution and the corpus callosum has been termed, very improperly, the " ventricle of the corpus callosum," and some longitudinal fibres (striae longitudinales laterales), which are brought into view when the convolution is raised, were called by Reil the " covered band." If, now7, the upper part of each hemisphere be removed to a level with the corpus callosum, a large ex- panse of medullary matter, surrounded by a zigzag line of grey substance corresponding with the convolutions and sulci ofthe two hemispheres, will be seen; this is the centrum ovale majus of Vieussens. *In estimating the surface of the brain, which, according to Baillarger. averages in round numbers, 670 square inches, these convolutions and the laminae of the cerebellum are supposed to be unfolded. | James Dubois, a celebrated professor of anatomy in Paris, where he succeeded Vi- dius in 1550, although known much earlier by his works and discoveries, but particu larly by his violence in the defence of Galen. His name was latinised to Jacobus Sylvius. LATERAL VENTRICLES. 373 The Corpus callosum (callosus, hard) is a thick layer of medullary fibres passing transversely between the two hemispheres, and constituting their great commissure. It is situated in the middle line of the centrum ovale ma- jus, but nearer the anterior than the posterior part of the brain, and termi- nates anteriorly in a rounded border (genu), which may be traced down- wards to the base of the brain in front of the commissure of the optic nerves. Posteriorly it forms a thick rounded fold (splenium), which is continuous with the fornix. The length of the corpus callosum is about four inches. Beneath the posterior rounded bor- der of the corpus callosum is the trans- verse fissure of the cerebrum, which extends between the hemispheres and crura cerebri from near the fissure of Sylvius on one side, to the same point on the opposite side of the brain. It is through this fissure that the pia mater communicates with the velum interpositum. And it was here that Bichat conceived the arachnoid to enter the ventricles ; hence it is also named the fissure of Bichat. Along the middle line of the corpus callosum is the raphe, a linear de- pression between two slightly elevated longitudinal bands (chordae longi- tudinales, Lancisii); and, on either side of the raphe, may be seen the linee transverse, which mark the direction of the fibres of which the cor- pus callosum is composed. These fibres may be traced into the hemi- spheres on either side, and they will be seen to be crossed at about an inch from the raphe by the longitudinal fibres ofthe covered band of Red. Anteriorly and posteriorly the fibres of the corpus callosum curve into their corresponding lobes. If, now, a superficial incision be made through the corpus callosum on either side of the raphe, two irregular cavities will be opened, which ex- tend from one extremity of the hemispheres to the other: these are the lateral ventricles. To expose them completely, their upper boundary should be removed with the scissors. In making this dissection the thin and diaphanous membrane ofthe ventricles may frequently be seen. Lateral vkntricles.—Each lateral ventricle is divided into a central cavity, and three smaller cavities called cornua. The anterior cornu curves forwards and outwards in the anterior lobe; the middle cornu] de- scends into the middle lobe ; and the posterior cornu passes backwards in the posterior lobe, converging towards its fellow of the opposite side. The central cavity is triangular in form, being bounded above (roof) by the corpus callosum ; internally by the septum lucidum, which separates * A section of the brain showing the centrum ovale majus and corpus callosum 1 1 Th* anterior lobes of the brain. 2, 2. The posterior lobes. 3, 3. The longitudina. fi fr. e p1. of the falx cerebri. 4, 4. The roof of the lateral ventricles J%UT1 l\lm. of He corpus callosum. 6. Its body, upon which the lines transversa* 5, 5. The genu of he ™V caHosi s The h6. 9> 9. The striae long. are seen. 7, /. i ne >i'n-'"" i -„ •■ tudinales laterals, or covered bands of Reil. 32 374 THALAMUS OPTICUS. it from the opposite ventricle ; and below (floor) by the following parts, taken in their order of position from before backwards :— Corpus striatum, Tenia semicircularis, Thalamus opticus, Choroid plexus, Corpus fimbriatum, Fornix. The Corpus striatum is named from the striated lines of white and grey matter which are seen upon cutting into its substance. It is grey on the exte- rior, and of a pyriform shape. The broad end, directed forwards, rests against the corpus striatum of the op- posite side : the small end, backwards, is separated from its fellow by the in- terposition of the thalami optici. The corpora striata are the superior ganglia ofthe cerebrum. The Tenia semicircularis (tenia, a fillet) is a narrow band of medullary substance, extending along the poste- rior border of the corpus striatum, and serving as a bond of connexion between that body and the thalamus opticus. The tenia is partly concealed by a large vein (vena corporis striati), which ter- minates in the vena Galeni of its own side. The vein is formed by small vessels from the corpus striatum and thalamus opticus, and is overlaid by a yellowish band, a thickening of the lining membrane of the ventricle. This was first noticed and described by Tarinus, under the name of the horny band. We may therefore term it tenia Tarini.\ The Thalamus opticus (thalamus, a bed) is an oblong body, having a * The lateral ventricles of the cerebrum. 1, 1. The two hemispheres cut down to a level with the corpus callosum so as to constitute the centrum ovale majus. The sur- face is seen to be studded with the small vascular points—puncta vasculosa; and sur- rounded by a narrow margin which represents the grey substance. 2. A small portion of the anterior extremity (genu) of the corpus callosum. 3. Its posterior boundary (splenium); the intermediate portion forming the roof of the lateral ventricles has been removed so as to expose completely those cavities. 4. A part of the septum lucidum, showing an interspace between its layers—the fifth ventricle. 5. The anterior cornu of one side. 6. The commencement of the middle cornu 7. The posterior cornu. 8. The corpus striatum of one ventricle. 9. The tenia semicircularis covered by the vena corporis striati and tenia Tarini. 10. A small part of the thalamus opticus. 11. The dark fringe-like body to the left of the numeral is the choroid plexus. This plexus communicates with that of the opposite ventricle through the foramen of Monro, or fo- ramen commune anterius ; a bristle is passed through this opening (under figure 4), and its extremities are seen resting on the corpus striatum at each side. The figure 11 rests upon the edge of the fornix, on that part of it which is called the corpus fimbria tum. 12. The fornix. 13. The commencement of the hippocampus major descending into the middle cornu. The rounded oblong body in the posterior cornu of the lateral ventricle, directly behind the figure 13, is the hippocampus minor. | Peter Tarin. a French anatomist; his work, entitled "Adversaria Anatomica," was published in 1750. CHOROID PLEXUS. 375 thin coating of white substance on its surface; it has received its name from giving origin to one root of the optic nerve. It is the inferior gan- glion of the cerebrum. Part only of the thalamus is seen in the floor of the lateral ventricle ; we must, therefore, defer its further description until ,ve can examine it in its entire extent. The Choroid plexus (x<^|0V5 e^°s, resembling the chorion*) is a vascular fringe extending obliquely across the floor of the lateral ventricle, and sinking into the middle cornu. Anteriorly, it is small and tapering, and communicates with the choroid plexus of the opposite ventricle, through a large oval opening, the foramen of Monro, or foramen commune ante- rius. This foramen may be distinctly seen by pulling slightly on the plexus, and pressing aside the septum lucidum with the handle of the knife. It. is situated between the under surface of the fornix, and the an- terior extremities of the thalami optici, and forms a communication trans- versely between the lateral ventricles, and perpendicularly with the third ventricle. The choroid plexus presents upon its surface a number of minute vas- cular processes, which are termed villi. They are invested by a very delicate epithelium, surmounted by cilia, which have been seen in active movement in the embryo. In their interior the plexuses not unfrequently contain particles of calcareous matter, and they are sometimes covered by small clusters of serous cysts. The Corpus fimbriatum is a narrow white band, wirich is situated im- mediately behind the choroid plexus, and extends with it into the de- scending cornu of the lateral ventricle. It is, in fact, the lateral thin edge of the fornix, and being attached to the hippocampus major in the de- scending horn of the lateral ventricle, it is also termed, tenia hippocampi. The Fornix is a white layer of medullary substance, of which a portion only is seen in this view of the ventricle. The Anterior cornu is triangular in its form, sweeping outwards, and terminating by a point in the anterior lobe of the brain, at a short distance from its surface. The Posterior cornu or digital cavity curves inwards, as it extends back into the posterior lobe of the brain, and likewise terminates near the sur- face. An elevation corresponding with a deep sulcus between two convo- lutions projects into the area of this cornu, and is called the hippocampus minor. The Middle or descending cornu, in descending into the middle lobe of the brain, forms a very considerable curve, and alters its direction several times as it proceeds. Hence it is described as passing backwards and outwards and dow7nw7ards, and then turning forwards and inwards. This complex expression of a very simple curve has given origin to a symbol formed by the primary letters of these various terms; and by means of this the student recollects with ease the course of the cornu, bodfi. It is* the largest of the three cornua, and terminates close to the fissure of Syl- vius, after having curved around the crus cerebri. The middle cornu should now be laid open, by inserting the little finger into its cavity, and making it serve as a director for the scalpel in cutting away the side'of the hemisphere, so as to expose it completely. The Superior boundary of the middle cornu is formed by the under sur- * See the note appended to the description of the choroid coat of the eye-ball. 376 FASCIA DENTATA. face of the thalamus opticus, upon which are the two projections called corpus geniculatum internum and externum ; and the inferior wall by the various parts which are sometimes spoken of as the contents of the middle cornu : these are the— Hippocampus major, Pes hippocampi, Pes accessorius, Corpus fimbriatum, Choroid plexus, Fascia dentata, Transverse fissure. The Hippocampus major or cornu Ammonis, so called from its resem- blance to a ram's horn, the famous crest of Jupiter Ammon, is a consider- able projection from the inferior wall, and extends the whole length ofthe middle cornu. Its extremity is likened to the foot of an animal, from its presenting a number of knuckle-like elevations upon the surface, and is named pes hippocampi. The hippocampus major is the internal surface of the convolution (gyrus fornicatus) of the lateral edge of the hemisphere, the convolution which has been previously described as lying upon the corpus callosum and extending downwards to the base of the brain to terminate at the fissure of Sylvius. If it be cut across, the section will be seen to resemble the extremity of a convoluted scroll, consisting of alter- nate layers of white and grey substance. The hippocampus major is con- tinuous superiorly with the fornix and corpus callosum, deriving from the latter its medullary layer. The Pes accessorius is a swelling somewhat resembling the hippocampus major, but smaller in size; it is situated on the outer wall of the cornu, and is frequently absent. The Corpus fimbriatum (tenia hippocampi) is the narrow white band which is prolonged from the central cavity ofthe ventricle, and is attached along the inner border of the hippocampus major. It is lost inferiorly on the hippocampus. Fascia dentata:—if the corpus fimbriatum be carefully raised, a narrow serrated band of grey substance, the margin of the grey substance of the middle lobe, will be seen beneath it; this is the fascia dentata. Beneath the corpus fimbriatum will be likewise seen the transverse fissure of the brain, which has been before described as extending from near the fissure of Sylvius on one side, across to the same point on the opposite side of the brain. It is through this fissure that the pia mater communicates with the choroid plexus, and the latter obtains its supply of blood. The fissure is bounded on one side by the corpus fimbriatum, and on the other by the under surface of the thalamus opticus. The internal boundary of the lateral ventricle is the septum lucidum. This septum is thin and semi-transparent, and consists of two lamina? of cerebral substance attached above to the under surface of the corpus cal- losum at its anterior part, and below to the fornix. Between the two layers is a narrow space, the fifth ventricle, which is lined by a prcper membrane. The fifth ventricle may be shown, by snipping through the septum lucidum transversely with the scissors. The corpus callosum should now be cut across towards its anterior ex- FORNIX. 377 tremity, and the two ends carefully dissected away. The anterior portion will be retained only by the septum lucidum, but the posterior will be found incorporated with the white layer beneath, which is the fornix. Fornix. — The fornix (arch) is a triangular lamina of white substance, broad behind, and extending into each lateral ventricle: narrow in front, where it terminates in two crura, which arch downwards to the base of the brain. The two crura descend in a curved direction to the base of the brain, embedded in grey substance, in the lateral walls of the- third ventricle, and lying-directly behind the anterior commissure. At the base of the brain they make a sudden curve upon themselves and constitute the corpora albicantia, from which they may be traced upwards to their origin in the thalami optici. Opening transversely beneath these two crura, just as they are about to arch downwards, is the foramen of communication between the lateral and the third ventricles, the foramen of Monro; or foramen commune anterius. The choroid plexuses communicate, and the veins of the corpora striata pass through this opening. The lateral thin edges of the fornix are continuous posteriorly with the concave border ofthe hippocampus major at each side, and form the nar- row white band called corpus fimbriatum (posterior crus of the fornix). In the middle line the fornix is continuous with the corpus callosum, and at each side with the hippocampus major and minor. Upon the under surface of the fornix towards its posterior part, some transverse lines are seen passing between the diverging corpora fimbriata: this appearance is termed the lyra (corpus psalloides), from a fancied resemblance to the strings of a harp. The fornix may now be removed by dividing it across anteriorly, and turning it backwards, at the same time separating its lateral connexions with the hippocampi. If the student examine its under sur- face, he will perceive the lyra above described. Beneath the fornix is the velum interpositum, a duplica- ture of pia mater introduced into the interior of the brain, through the transverse fissure. The velum is continuous at each side with the choroid plexus, and contains in its in- ferior layer two large veins (the vene Galeni) which re- * The mesial surface of a longitudinal section of the brain. The incision has been carried along the middle line; between the two hemispheres of the cerebrum, and through the middle of the cerebellum and medulla oblongata. 1. The inner surface of the left hemisphere. 2. The divided surface ofthe cerebellum, showing the arbor vitse. 3. The medulla oblongata. 4. The corpus callosum curving downwards in front to ter- minate at the base of the brain, and rounded behind to become continuous with 5, the fornix. 6. One ofthe crura ofthe fornix descending to 7, one ofthe corpora albicantia. 8. The septum lucidum. 9. The velum interpositum, communicating with the pia mater ofthe convolutions through the fissure of Bichat. 10. Section ofthe middle commissure Mtuated in the third ventricle. 11. Section of the anterior commissure. 12. Section of the posterior commissure; the commissure is somewhat above and to the left of the numeral. The interspace between 10 and 11 is the foramen commune anterius. in which the cms of the fornix (0) is situated. The interspace between 10 and 12 is the 32* 378 THALAMI OPTICI--THIRD VENTRICLE. ceive the blood from the corpora striata and choroid plexuses, and termi- nate posteriorly, after uniting into a single trunk, in the straight sinus. Upon the under surface of the velum interpositum are two fringe-like bodies, which project into the third ventricle. These are the choroid plexuses of the third ventricle; posteriorly these fringes enclose the pineal gland. If the velum interpositum be raised and turned back, an operation which must be conducted with care, particularly at its posterior part, where it invests the pineal gland, the thalami optici and the cavity of the third ventricle will be brought into view. Thalami optici. — The thalami optici are two oblong, square-shaped bodies, of a white colour superficially, inserted between the two diverging portions of the corpora striata. In the middle line a fissure exists between them, which is called the third ventricle. Posteriorly and inferiorly, they form the superior wall of the descending cornu, and present two rounded elevations called corpus geniculatum externum and internum. The corpus geniculaium externum is the larger of the two, and of a greyish colour; it is the principal origin ofthe optic nerve. Anteriorly, the thalami are con- nected with the corpora albicantia by means of two white bands, which appear to originate in the white substance uniting the thalami to the cor- pora striata. Externally they are in relation with the corpora striata and hemispheres. In their interior the thalami are composed of white fibres mixed with grey substance. They are essentially the inferior ganglia of tlie cerebrum. Third ventricle.— The third ventricle is the fissure between the two thalami optici. It is bounded above by the under surface of the velum interpositum, from which are suspended the choroid plexuses of the third ventricle. Its floor is formed by the grey substance ofthe anterior termi- nation of the corpus callosum, called lamina cinerea, the tuber cinereum, corpora albicantia, and locus perforatus. Laterally it is bounded by the thalami optici; anteriorly by the anterior commissure and crura of the fornix ; and posteriorly by the posterior commissure and the iter a tertio au quartum ventriculum. The third ventricle is crossed by three com- missures, anterior, middle, and posterior; and between these are two spaces, called foramen commune anterius and foramen commune posterius. The Anterior commissure is a small rounded white cord, which enters the corpus striatum at either side, and spreads out in the substance of the hemispheres; the middle, or soft commissure consists of grey matter, which is continuous with the grey lining of the ventricle, it connects the adjacent sides of the thalami optici; the posterior commissure, smaller than the anterior, is a rounded white cord, connecting the two thalami optici posteriorly. The space between the anterior and middle commissure is called the foramen commune anterius, and is that to w7hich Monro has given his name (foramen of Monro). It is the medium of communication between foramen commune posterius. 1 3. The corpora quadrigemina, upon which is seen rest- ing the pineal gland, 14. 15. The iter a tertio ad quartum ventriculum, or aqueduct of Sylvius. 16. The fourth ventricle. 17. The pons Varolii, through which are seen pass- ing the diverging fibres of the corpora pyramidalia. 18. The crus cerebri of the left side, with the third nerve arising from it. 19. The tuber cinereum, from which pro- jects the infundibulum, having the pituitary gland appended to its extremity. 20. One of the optic nerves. 21. The left olfactory nerve terminating anteriorly in a roundpd ,ulb. FOURTH VENTRICLE. 379 the lateral and third ventricles, and it transmits superiorly the choroid plexus and the venae corporum striatorum. The foramen commune ante- rius is also termed, iter ad infundibulum, from leading downwards to the funnel-shaped cavity of the infundibulum. The crura of the fornix are embedded in the lateral walls of the foramen commune, and are concealed from view in this situation by the layer of grey substance which lines the interior of the third ventricle. If the crura be slightly separated, the an- terior commissure will be seen immediately in front of them, crossing from one corpus striatum to the other. The space between the middle and posterior commissure is the foramen commune posterius ; it is much shal- lower than the preceding, and is the origin of a canal, the aqueduct of Sylvius or iter a tertio ad quartum ventriculum, which leads backwards beneath the posterior commissure and through the base of the corpora quadrigemina to the upper part ofthe fourth, ventricle. Corpora quadrigemina.—The corpora quadrigemina, or optic lobes, are situated immediately behind the third ventricle and posterior commis- sure ; and beneath the posterior border of the corpus callosum. They form, indeed, at this point, the inferior boundary of the transverse fissure of the hemispheres, the fissure of Bichat. The anterior pair of these bodies are grey in colour, and are named nates : the posterior pair are white and much smaller than the anterior; they are termed testes. From the nates on each side may be traced a rounded process (brachium anterius) which passes obliquely outwards into the thalamus opticus; and from the testis a similar but smaller process (brachium posterius) which has the same destination. The corpus geniculatum internum lies in the interval of these two processes where they enter the thalamus, and behind the bra- chium posterius is a prominent band (laqueus) which marks the course of the superior division of the fasciculus olivaris. The corpora quadrigemina are perforated longitudinally through their base by the aqueduct of Syl- vius ; they are covered in partly by the pia mater and partly by the velum interpositum, and the nates form the base of support of the pineal gland. Pineal Gland.—The pineal gland is a small reddish grey body of a conical form (hence its synonym conarium), situated on the anterior part of the nates and invested by a duplicature of pia mater derived from the under part of the velum interpositum. The pineal gland, when pressed between the fingers is found to contain a gritty matter (acervulus) com- posed chemically of phosphate and carbonate of lime, and is sometimes hollow in the interior. It is connected to the brain by means of two me- dullary cords called peduncles and a thin lamina derived from the posterior commissure ; the peduncles ofthe pineal gland are attached to the thalami optici, and may be traced along the upper and inner margin of those bodies to the crura ofthe fornix with which they become blended. From the close connexion subsisting between the pia mater and the pineal gland, and the softness of texture of the latter, the gland is liable to be torn away in the removal ofthe pia mater. Behind the corpora quadrigemina is the cerebellum, and beneath the cerebellum the fourth ventricle. The student must therefore divide the cerebellum down to the fourth ventricle, and turn its lobes aside to ex- amine that cavity. Fourth ventricle.—The fourth ventricle (sinus rhomboidalis) is the ventricle of the medulla oblongata, upon the posterior surface of w-hich, and of the pons Varolii, it is placed. It is a lozenge-shaped cavity, 380 LINING MEMBRANE OF THE VENTRICLES. bounded on each side by a thick cord passing between the cerebellum and corpora quadrigemina, called the processus e cerebello ad testes, and by the corpus restiforme. It is covered in behind by the cerebellum, and by a thin lamella of medullary substance, stretched between the two processus e cerebello ad testes, termed the valve of Vieussens* That portion of the cerebellum which forms the posterior boundary of the fourth ventricle, presents four small prominences or lobules, and a thin layer of medullary substance, the velum medullare posterius. Of the lobules twro are placed in the middle line, the nodulus and uvula, the for- mer being before the latter; the remaining two are named amygdala, or tonsils, and are situated one on either side of the uvula. They all project into the cavity of the fourth ventricle, and the velum medullare posterius is situated in front of them. The valve of Vieussens, or velum medullare anterius, is an extremely thin lamella of medullary substance, prolonged from the w7hite matter of the cerebellum to the testes, and attached on each side to the processus e cerebello ad testes. This lamella is overlaid for a short distance by a thin, transversely-grooved lobule of grey sub- stance (linguetta laminosa) derived from the anterior border of the cere- bellum, and its junction with the testes is strengthened by a narrow slip given off by the commissure of those bodies, the frenulum veli medullaris anterioris. The anterior wall, or floor of the fourth ventricle is formed by two slightly convex bodies, processus teretes or posterior pyramids, separated by a longitudinal groove which is continuous inferiorly with the fissura longitudinalis posterior of the spinal cord. The processus teretes are crossed transversely by several white and grey fasciculi (linee trans- versa) the origin ofthe auditory nerves. And upon the lower part ofthe floor of this ventricle is an impression resembling the point of a pen, and hence named calamus scriptorius; the lateral boundaries of the calamus are the processus clavati of the posterior median columns of the spinal cord. Above, the fourth ventricle is bounded by the corpora quadrige- mina and aqueduct of Sylvius; and below by a layer of pia mater and arachnoid, called the valve of the arachnoid. It is by rupture of this lat- ter that a communication is established between the ventricles of the brain and the sub-arachnoidean space. Within the fourth ventricle and lying against the uvula and tonsils are two small vascular fringes formed by the pia mater, the choroid plexuses of the fourth ventricle. The fourth ven- tricle is lined by grey matter derived from the interior of the spinal cord, the grey matter being partly concealed by a thin expansion of white sub- stance. LINING MEMBRANE OF THE VENTRICLES. The lining membrane of the ventricles is a serous layer distinct from the arachnoid; it lines the whole of the interior of the lateral ventricles, and is connected above and below with the attached border of the choroid plexus, so as to exclude all communication between the ventricles and the exterior of the brain. From the lateral ventricles it is reflected through the foramen of Monro on each side, into the third ventricle, which it in- vests throughout. From the third it is conducted into the fourth ventricle, through the iter a tertio ad quartum ventriculum, and lines its interior, to- * Raymond Vieussens, a great discoverer in the anatomy of the brain and nervous system. His " Neurographia Universalis" was published at Lyons, in 1685. CEREBELLUM. 381 gether with a layer of pia mater which forms its inferior boundary. In this manner a perfect communication is established between all the ven- tricles, with the exception of the fifth, which has its own proper membrane. It is this membrane which gives them their polished surface, and transudes the secretion which moistens their interior. When the fluid accumulates to an unnatural degree, it may then break down this layer and the layer of pia mater at the bottom of the fourth ventricle, and thus make its way into the sub-arachnoidean space; but in the normal condition it is doubt- ful whether a communication exists between the interior of the ventricles and the serous cavity of the sub-arachnoidean space. C EREBELLUM. The Cerebellum (figs. 171, 172, 173), seven times smaller than the cerebrum, is situated beneath the posterior lobes of the latter, being lodged in the posterior fossa of the base of the cranium, and protected from the superincumbent pressure of the cerebrum by the tentorium cerebelli. Like the cerebrum, it is composed of grey and white substance, the former occupying the surface, the latter the interior, and its surface is formed of parallel lamellae separated by sulci, and here and there by deeper sulci. In form, the cerebellum is oblong and flattened, its greater diameter being from side to side, its two surfaces looking upwards and downwards, and its borders being anterior, posterior, and lateral. In consideration of its shape the cerebellum admits of a division into two hemispheres, into cer- tain prominences termed processes and lobules, and into certain divisions of its substance called lobes, formed upon the hemispheres by the deeper sulci above referred to. The two hemispheres are separated from each other on the upper surface ofthe cerebellum by a longitudinal ridge which is termed the superior vermiform process, and which forms a commissure between them. On the anterior border of the organ there is a semilunar notch, incisura cerebelli anterior, which encircles the corpora quadrigemina posteriorly. On the posterior border there is another notch, incisura cere- belli posterior, which receives the upper part of the falx cerebelli; and on the under surface of the cerebellum is a deep fissure corresponding with the medulla oblongata, and termed the vallecula (valley). Each hemisphere of the cerebellum is divided by means of a fissure (sulcus horizontalis) which runs along its free border, into an upper and a lower portion, and upon each of these portions certain lobes are marked out. Thus on the upper portion there are two such lobes separated by a sulcus, somewhat more strongly marked than the rest, and extending deeper into the substance of the cerebellum ; they are the lobus superior anterior and lobus superior posterior. Upon the under portion of the hemisphere there are three such lobes, namely, lobus inferior anterior, medius, and posterior, and two additional ones of peculiar form, the lobus inferior internus or tonsil, and the flocculus. The tonsil (amygdala) is situated on the side of the vallecula, and projects into the fourth ventricle. The flocculus or pneumogastric lobule, long and slender, extends from the side of the vallecula around the corpus restiforme to the crus cerebelli, lying behind the filaments ofthe eighth pair of nerves. The commissure between the two hemispheres is termed the worm 'vermis), that portion of the worm which occupies the upper surface of the cerebellum as far back as the horizontal fissure being the processus 382 BASE OF THE BRAIN. vermiformis superior, and that which is lodged within the vallecula being the processus vermiformis inferior. The superior vermiform process is a prominent longitudinal ridge, extending from the incisura anterior to the incisura posterior cerebelli. In imitation of the hemispheres, it is divided into lobes, of which three have received names, namely, the lobulus cen* tralis, which is a small lobe situated in the incisura anterior; the monti- culus cerebelli, a longer lobe, having its peak and declivity; and a small lobe near the incisura posterior, the commissura simplex. The lobes of the inferior vermiform process are four in number, namely,—the commis- sura brevis, situated in the incisura posterior, below the horizontal fissure; the pyramid, a small, obtusely-pointed eminence ; a larger prominence, the uvula, situated between the tonsils, and connected with them by means of a commissure ; and in front of the uvula, the nodulus. In front of the nodulus is a thin lamina of medullary substance, consisting of a central and two lateral portions, the velum medullare posterius (valvula Tarini), and between this velum in front, and the nodulus and uvula behind, is a deep fossa which is known as the swallow's nest (nidus hirundinis). The velum medullare anterius is the valve of Vieussens, described with the fourth ventricle ; both these vela proceed from the same point in the roof of that ventricle, and separate from each other at an angle, the one passing obliquely forwards, the other obliquely backwards. When a vertical incision is made into the cerebellum, that appearance is seen which has been denominated arbor vita cerebelli; the white sub- stance in the centre of such a section resembles the trunk of a tree, from which branches are given off, and from the branches branchlets and leaves, the two latter being coated by a moderately thick and uniform layer of grey substance. If the incision be made somewiiat nearer the commissure than to the lateral border ofthe organ, a yellowish grey dentated line, en- closing medullary substance traversed by the openings of numerous vessels, will be seen in the centre of the white substance. This is the ganglion of the cerebellum, the corpus rhomboideum or dentatum, from which the peduncles of the cerebellum proceed. The grey line is dense and horny in structure, and is the cut edge of a thin capsule, open towards the medulla oblongata. The cerebellum is associated with the re.st of the encephalon by means of three pairs of rounded cords or peduncles, superior, middle, and infe- rior. The superior peduncles, or processus e cerebello ad testes, proceed from the cerebellum forwards and upwards to the testes, in which they are lost. They form the anterior part of the lateral boundaries of the fourth ventricle, and give attachment by their inner borders to the valve of Vieussens, which is stretched between them. At their junction with the testes they are crossed by the fourth pair of nerves. The middle pedun- cles, or crura cerebelli ad pontem, the largest of the three, issue from the cerebellum through the anterior extremity of the sulcus horizontalis, and are lost in the pons Varolii. The inferior peduncles, or crura ad medul- lam oblongatam, are the corpora restiformia which descend to the poste- rior part of the medulla oblongata, and form the inferior portion of the lateral boundaries of the fourth ventricle. BASE OF THE BRAIN. The student should now prepare to study the base ofthe brain : for this purpose the organ should be turned upon its incised surface ; and if the BASE OF THE BRAIN. 383 dissection have hitherto been conducted with care, he will find the base perfectly uninjured. The arachnoid membrane, some parts of the pia mater, and the circle of Willis, must be carefully cleared away, in order to expose all the parts to be examined. These he will find arranged in the following order from before backwards:__ Longitudinal fissure, Infundibulum, Olfactory nerves, Corpora albicantia, Fissure of Sylvius, Locus perforatus, Substantia perforata, Crura cerebri, Commencement of the trans- Pons Varolii, verse fissure, Crura cerebelli, Optic commissure, Medulla oblongata. Tuber cinereum, The Longitudinal fissure is the space separating the two hemispheres: it is continued downwards to the base of the brain, and divides the two anterior lobes. In this fissure the anterior cerebral arteries ascend towards the corpus callosum ; and, if the two lobes be slightly drawn asunder, the anterior border (genu) of the corpus callosum will be seen descending to the base of the brain. Arrived at the base of the brain, the corpus callo- sum terminates by a concave border, which is prolonged to the commis- sure of the optic nerves by a thin layer of grey substance, the lamina cinerea. The lamina cinerea is the anterior part of the inferior boundary ofthe third ventricle. On each side ofthe lamina cinerea the corpus cal- losum is continued into the substantia perforata and crura cerebri, and upon the latter forms a narrow medullary band lying externally to, and slightly overlapping the optic tract, the medulla innominata. Upon the under surface of each anterior lobe, on either side of the lon- gitudinal fissure, is the olfactory nerve, with its bulb. The Fissure of Sylvius bounds the anterior lobe posteriorly, and sepa- rates it from the middle lobe; it lodges the middle cerebral artery. If this fissure be followed outwards, a small isolated cluster of five or six convolutions will be observed ; these constitute the island of Reil. The island of Reil, together with the substantia perforata, form the base ofthe corpus striatum. The Substantia perforata is a triangular plane of white substance, situ- ated at the inner extremity of the fissure of Sylvius. It is named perfo- rata from being pierced by a number of openings for small arteries, w-hich enter the brain in this situation to supply the grey substance of the corpus striatum. Passing backwards on each side beneath the edge of the middle lobe, is the commencement of the great transverse fissure, which extends beneath the hemisphere of one side to the same point on the opposite side. A probe passed into this fissure between the cms cerebri and middle lobe would enter the middle cornu ofthe lateral ventricle. The Optic commissure is situated on the middle line; it is the point of communication between the two optic nerves. The Tuber cinereum is an eminence of grey substance situated immedi- ately behind the optic commissure, and in front of the corpora mammil- laria. From its centre there projects a small conical body of grey sub- stance, apparently a prolongation of the tuber cinereum, the infundibulum. The infundibulum is hollow in its interior, enclosing a short caecal canal, 384 BASE OF THE BRAIN. Fig. 172* which communicates with the cavity of the third ventricle ; and below the termination of the canal, the conical process becomes connected with the pituitary gland. The infundibulum and tuber cinereum form part of the floor of the third ventricle. The Pituitary gland (hypophysis cerebri), is a small, flattened, reddish- grey body situated in the sella turcica, and closely retained in that situation by the dura mater and arachnoid. It consists of two lobes, closely pressed together, the anterior lobe being the larger of the two, and oblong in shape, the posterior round. Both lobes are connected with the infundibulum, but the latter is so soft in texture as to be generally torn through in the removal of the brain. Indeed, for the purposes of the student, it is better to effect this separation with the knife, and leave the pituitary body in situ, to be examined with the base of the cranium. The Corpora albicantia (mammillaria, pisiformia, bulbi fornicis) are two white convex bodies, having the shape and size of peas, situated behind the tuber cinereum, and between the crura cerebri. They are a part of the crura of the fornix, w-hich, after their origin from the thalami optici, descend to the base ofthe brain, and making a sudden curve upon them- selves previously to their ascent to the lateral ventricles, constitute the cor- pora albicantia. When divided by section, these bodies will be found to be composed of a capsule of white substance, containing grey matter, the grey matter of the two corpora being connected by means of a commissure. The Locus perforatus is a layer of whitish-grey substance, connect- ed in front with the corpora albi- cantia, behind with the pons Varo- lii, and on each side with the crura cerebri, between which it is situated. It is perforated by several thick tufts of arteries, which are distributed to the thalami optici and third ven- tricle, of winch latter it assists in forming the floor. It is sometimes called the pons Tarini. The Crura cerebri are two thick white cords, which issue from the anterior border of the pons Varolii, and diverge to each side to enter the thalami optici. By their outer side the crura cerebri are continu- ous with the corpora quadrigemina, and, above, they constitute the lower boundary ofthe aqueduct of * The under surface or base of the brain. 1. The anterior lobe of one hemisphere ofthe cerebrum. 2. The middle lobe. 3. The posterior lobe almost concealed by (4) the hemisphere of the cerebellum. 5. The pyramidal lobe of the inferior vermiform process of the cerebellum. 6. The pneumogastric lobule. 7. The longitudinal fissure. 8. The olfactory nerves, with their bulbous expansions. 9. The substantia perforata at the inner termination ofthe fissure of Sylvius; the three roots ofthe olfactory nerve are seen upon the substantia perforata. The commencement of the transverse fissure on each side is concealed by the inner border ofthe middle lobe. 10. The commissure of the optic nerves; the numeral is placed between the optic nerves as they diverge from the commissure, and rests upon the lamina cinerea of the corpus callosum. 11. The �74289 MEDULLA OBLONGATA. 385 Sylvius. In their interior they contain grey matter, which has a semilunai shape when the crus is divided transversely, and has been termed the locus niger. The third nerve will be observed to arise from the inner side of each, and the fourth nerves wind around their outer border from above. The Pons Varolii* (protuberantia annularis, nodus encephali), is the broad transverse band of white fibres which arches like abridge across the upper part of the medulla oblongata ; and, contracting on each side into a thick rounded cord, enters the substance ofthe cerebellum under the name of crus cerebelli. There is a groove along its middle which lodges the basilar artery. The pons Varolii is the commissure ofthe cerebellum, and associates the tw7o lateral lobes in their common function. Resting against the pons, near its posterior border, is the sixth pair of nerves. On the anterior border of the crus cerebelli, at each side, is the thick bundle of filaments belonging to the fifth nerve, and, lying against its posterior border, the seventh pair of nerves. The upper surface of the pons forms a part of the floor of the fourth ventricle. MEDULLA OBLONGATA. The medulla oblongata (bulbus rhachidicus), is the upper enlarged por- tion of the spinal cord. It is somewhat conical in shape, and a little more than an inch in length, extending from the pons Varolii to a point corre- sponding with the upper border ofthe atlas. On the middle line, in front and behind, the medulla oblongata is marked by two vertical fissures, the fissura longitudinalis anterior and posterior, which divide it superficially into two symmetrical lateral cords or columns; whilst each lateral column is subdivided by minor grooves into three smaller cords, namely, the cor- pora pyramidalia, corpora olivaria, and corpora restiformia. The Corpora pyramidalia are two narrow convex cords, tapering slightly from above downwards, and situated one on either side of the fissura lon- gitudinalis anterior. At about an inch below the pons the corpora pyra- midalia communicate very freely across the fissure by a decussation of their fibres, and at their point of entrance into the pons they are constricted into round cords. The fissura longitudinalis is somewhat enlarged by this constriction, and the enlarged space has received the name of foramen caecum of the medulla oblongata. The Corpora olivaria (named from some resemblance to the shape of an olive), are two oblong, oval-shaped, convex bodies, of about the same breadth with the corpora pyramidalia, about half an inch in length, and tuber cinereum, from which the infundibulum is seen projecting. 12. The corpora al- bicantia. 13. The locus perforatus, bounded on each side by the crura cerebri, and by the third nerve. 14. The pons Varolii. 15. The crus cerebelli of one side. 16. The fifth nerve emerging from the anterior border of the crus cerebelli; the small nerve by its side is the fourth. 17. The sixth pair of nerves. 18. The seventh pair of nerves con- sisting ofthe auditory and facial. 19. The corpora pyramidalia ofthe medulla oblongata; the corpus olivare and part of the corpus restiforme are seen at each side. Just below the numeral is the decussation ofthe fibres ofthe corpora pyramidalia. 20. The eighth pair of nerves. 21. The ninth or hypoglossal nerve. 22. The anterior root of the first cervical spinal nerve. * Constant Varolius, Professor of Anatomy in Bologna: died in 1578. He dissected the brain in the course of its fibres, beginning from the medulla oblongata ; a plan which has since been perfected by Vieussens, and by Gall and Spurzheim. The work con taining his mode of dissection, " De Resolutione Corporis Humani," was published aftei his death, in 1591. 33 z 386 DIVERGING FIBRES. somewiiat larger above than below. The corpus olivare is situated imme- diately external to the corpus pyramidale, from which, and from the corpus restiforme, it is separated by a well-marked groove. In this groove some longitudinal fibres are seen which enclose the base of the corpus olivare, and have been named funiculi siliqua, those which lie to its inner side being the funiculus internus, and those to its outer side the funiculus ex- ternus. Besides these there are other fibres which cross the corpus olivare obliquely, these are the fibre arciformes. When examined by section (Fig. 175), the corpus olivare is found to be a ganglion deeply embedded in the medulla oblongata, and meeting.its fellow at the middle line behind the corpus pyramidale. The ganglion of the corpus olivare (corpus den- tatum, nucleus olivae), like that ofthe cerebellum, is a yellowish-grey den- tated capsule, open behind, and containing medullary substance from which a fasciculus of fibres proceeds upwards to the corpora quadrigemina and thalami optici. The nervous filaments which spring from the groove on the anterior border of the corpus olivare, are those of the hypoglossal nerve; and those on its posterior border are the glosso-pharyngeal and pneumogastric. The Corpora restiformia (restis, a rope), comprehend the whole of the posterior half of each lateral column of the medulla oblongata. They are ' separated from the corpora olivaria by the grooves already spoken of; posteriorly they are divided from each other by the fissura longitudinalis posterior and by the fourth ventricle, and superiorly they diverge and curve backwards to enter the cerebellum, and constitute its inferior peduncles. Along the posterior border of each corpus restiforme, and marked off from that body by a groove, is a narrow white cord, separated from its fellow by the fissura longitudinalis posterior. This pair of narrow cords are termed the posterior median columns or fasciculi (funiculi graciles). Each fasciculus forms an enlargement (processus clavatus) at its upper end, and is then lost in the corresponding corpus restiforme. The processus clavati are the lateral boundaries of the nib of the calamus scriptorius. The cor- pus restiforme is crossed near its entrance into the cerebellum, by the au- ditory nerve, the choroid plexus of the fourth ventricle, and the pneumo- gastric lobule. _ The remaining portion of the medulla oblongata visible from the exte- rior, are the two slightly convex columns which enter into the formation of the floor of the fourth ventricle. These columns are the funiculi teretes or posterior pyramids. Diverging fibres.—The fibres composing the columns of the medulla oblongata have a special arrangement on reaching the upper part of that body, those ofthe corpora pyramidalia and olivaria enter the pons Varolii, and are thence prolonged through the crura cerebri, thalami optici, and corpora striata to the cerebral hemispheres; but those of the corpora resti- formia are reflected backwards into the cerebellum and form its inferior peduncles. From pursuing this course, and spreading out as they advance, these fibres have been termed by Gall the diverging fibres. . While situated , within the pons, the fibres of the corpus pyramidale and olivare separate and spread out, and have grey substance interposed between them ; and they quit the pons much increased in number and bulk, so as to form the crus cerebri. The fibres of the crus cerebri again are separated in the thalamus opticus, and are intermingled with grey matter, and they also FIBRES OF THE BRAIN. 387 Fig. 173.» quit that body greatly increased in number and bulk. Precisely the same change takes place in the corpus striatum, and the fibres are now so extra- ordinarily multiplied as to be ca- pable of forming a large proportion of the hemispheres. Observing this remarkable in- crease in the white fibres, appa- rently from the admixture of grey substance, Gall and Spurzheim considered the latter as the mate- rial of increase or formative sub- stance to the white fibres, and they are borne out in this conclusion by several collateral facts, among the most prominent of which is the great vascularity of the grey sub- stance; and the larger proportion of the nutrient fluid circulating through it is fully capable of effect- ing the increased growth and nu- trition of the structures by which it is surrounded. For a like rea- son, the bodies in which this grey substance occurs, are called by the same physiologists " ganglia of increase,'''' and by other authors simply ganglia. Thus the thalami optici and corpora striata are the ganglia of the cerebrum; or, in other words, the formative ganglia of the hemispheres. The fibres of the corpora pyramidalia are not all of them destined to the course above described; several fasciculi curve outwards to reach the cor- pora restiformia, some passing in front and some behind the corpus olivare on each side. These are the arciform fibre's, and they are distinguished by Mr. Solly into the superficial and deep cerebellar fibres. In the pons Varolii the continued or cerebral fibres (Solly) of the corpus pyramidale are placed between the superficial and deep layers of transverse fibres, and escaping from the pons, constitute the inferior and inner segment of the crus cerebri. From the crus cerebri they pass for the most part be- neath the thalami optici into the corpora striata. * The base of the brain, upon which several sections have been made, showing the distribution of the diverging fibres. 1. The medulla oblongata. 2. One half of the pons Varolii. 3. The crus cerebri crossed by the optic nerve (4) and spreading out into the hemisphere to form the corona radiata. 5. The optic nerve near its origin ; the nerves about the cms cerebri and cerebelli are the same as in the preceding figure. 6. Ihe olfactory nerve. 7. The corpora albicantia. On the right side a portion of the brain has been removed to show the distribution ofthe diverging fibres. 8. The fibres ofthe corpus pyramidale passing through the substance ofthe pons Varolii. 9. Ihe fibres passing through the thalamus opticus. 10. The fibres passing through the corpus striatum 11 Their distribution to the hemisphere. 12. The fifth nerve: its two roots may be traced the one forwards to the fibres of the corpus pyramidale, the other back- wards to the fasciculi teretes. 13. The fibres ofthe corpus pyramidale which pass out- wards with the corpus restiforme into the substance of the cerebellum ; these are the arciform fibres of Solly. The fibres referred to are those below the numeral, the nu- meral itself rests upon the corpus olivare. 14. A section through one of the hemi- spheres of the cerebellum, showing the corpus rhomboideum in the centre of its white substance; the arbor viae is also seen. 15. The opposite hemisphere of the cere- bellum 388 CONVERGING FIBRES. The fibres which enclose the corpus olivare, under the name of fasciculi siliquae, are separated by that body into two bands ; the innermost of the two hands, funiculus siliqua internus, accompanies the fibres of the corpus pyramidale into the crus cerebri. The funiculus siliqua externus unites with a fasciculus proceeding from the nucleus olivas, and the combined column ascending behind the crus cerebelli divides into a superior and an inferior band. The inferior band proceeds with a fasciculus presently to be described, the fasciculus innominatus, into the upper segment of the crus cerebri. The superior band (laqueus) ascends by the side of the pro- cessus e cerebello ad testes, and, crossing the latter obliquely, enters the corpora quadrigemina, in which many of its fibres are distributed, while the rest are continued onwards into the thalamus opticus. The corpora restiformia derive their fibres from the anterior as w7ell as from the posterior columns ofthe medulla oblongata; they diverge as they approach the cerebellum, and leaving behind them the cavity of the fourth ventricle, enter the substance of the cerebellum, under the form of two rounded cords. These cords envelope the corpora rhomboidea, or gan- glia of increase, and then expand on all sides so as to constitute the cere- bellum. Besides the fibres here described, there are, in the interior of the me- dulla oblongata, behind the corpora olivaria, and more or less apparent between these bodies and the corpora restiformia, two large bundles of fibres, the fasciculi innominata. These fasciculi ascend behind the deep transverse fibres of the pons Varolii, and become apparent in the floor of the fourth ventricle, under the name of fasciculi teretes, or posterior pyramids. From this point they are prolonged upwards beneath the cor- pora quadrigemina into the crura cerebri, of which they form the upper and outer segment, and are thence continued through the thalami optici and corpora striata into the hemispheres. The locus niger of the crus cerebri is a septum of grey matter interposed between these fasciculi and those of the corpora pyramidalia. Converging fibres. — In addition to the diverging fibres which are thus shown to constitute both the cerebrum and cerebellum, by their increase and development, another set of fibres are found to exist, which have for their office the association of the symmetrical halves and distant parts of the same hemispheres. These are called, from their direction, converging fibres, and from their office, commissures. The commissures of the cerebrum and cerebellum are the— Corpus callosum, Fornix, Septum lucidum, Anterior commissure, Middle commissure, Posterior commissure, , Peduncles of the pineal gland, Pons Varolii. The Corpus callosum is the commissure of the hemispheres. It is therefore of moderate thickness in the middle, where its fibres pass directly from one hemisphere to the other; thicker in front (genu), where the anterior lobes are connected; and thickest behind (splenium), where SPINAL CORD. 389 the fibres from the posterior lobes are assembled. The fibres which curve backwards into the posterior lobes from the splenium of the corpus callo- sum have been termed forceps, those which pass directly outwards into the middle lobes from the same point, tapetum, and those which curve forwards and inwards from the genu to the anterior lobes, forceps anterior. The Fornix is an antero-posterior commissure, and serves to connect a number of parts. Below, it is associated with the thalami optici; on each side, by means of the corpora fimbriata, with the middle lobes of the brain; and, above, with the corpus callosum, and consequently with the hemispheres. The Septum lucidum is a perpendicular commissure between the fornix and corpus callosum. The Anterior commissure traverses the corpus striatum, and connects the anterior and middle lobes of opposite hemispheres. The Middle commissure is a layer of grey substance, uniting the thalami optici. The Posterior commissure is a white rounded cord, connecting the thalami optici. The Peduncles of the pineal gland must also be regarded as commis- sures, assisted in their function by the grey substance of the gland. The Pons Varolii is the commissure to the two hemispheres of the cere- bellum. It consists of transverse fibres, which are split into two layers by the passage of the fasciculi of the corpora pyramidalia and corpora olivaria. These two layers, the superior and inferior, are collected together on each side, in the formation of the crura cerebelli. SPINAL CORD. The dissection of the spinal cord requires that the spinal column should be opened through its entire length by sawing through the laminae of the vertebrae, close to the roots of the transverse processes, and raising the arches with a chisel; the muscles of the back having been removed as a preliminary step. The Spinal column contains the spinal cord, or medulla spinalis; the roots of the spinal nerves; and the membranes of the cord, viz. the dura mater, arachnoid, pia mater, and membrana dentata. The Dura mater spinalis (theca vertebralis) is a cylindrical sheath of fibrous membrane, identical in structure with the dura mater of the skull, and continuous with that membrane. At the margin of the occipital fora- men it is closely adherent to the bone; by its anterior surface it is attached to the posterior common ligament, and below, by means of its pointed y extremity, to the coccyx. In the rest of its extent it is comparatively free, beino- connected, by a very loose areolar tissue only, to the walls of the spinaf canal. In this areolar tissue there exists a quantity of reddish, oily, adipose substance, somewhat analogous to the marrow of long bones. On either side and below, the dura mater forms a sheath for each of the spinal nerves, to which it is closely adherent. Upon its inner surface it is smooth being lined by the arachnoid; and on its sides may be seen double openings for the two roots of each of the spinal nerves. The Arachnoid is a continuation of the serous membrane of the brain. It encloses the cord very loosely, being connected to it only by long 33* 390 SPINAL CORD. slender filaments* of areolar tissue, and by a longitudinal lamella which is attached to the posterior aspect of the cord. The areolar tissue is most abundant in the cervical region, and diminishes in quantity from above downwards; and the longitudinal lamella is complete only in the dorsal region. The arachnoid passes off from the cord on either side with the spinal nerves, to which it forms a sheath; and is then reflected on the dura mater, to constitute its serous surface. A connexion exists in several situations between the arachnoid of the cord and that of the dura mater. The space between the arachnoid and the spinal cord is identical with that already described as existing between the same parts in the brain, the sub-arachnoidean space. It is occupied by a serous fluid, sufficient in quantity to expand the arachnoid, and fill completely the cavity of the theca vertebralis. The sub-arachnoidean fluid keeps up a constant and gentle pressure on the entire surface of the brain and spinal cord, and yields with the greatest facility to the various movements of the cord, giving to those delicate structures the advantage of the principles so use- fully occupied by Dr. Arnott in the hydrostatic bed. The Pia mater is the immediate investment of the cord ; and, like the other membranes, is continuous with that of the brain. It is not, however, like the pia mater cerebri, a vascular membrane; but is dense and fibrous in structure, and contains but few vessels. It invests the cord closely, and sends a duplicature into the fissura longitudinalis anterior, and an- other, extremely delicate, into the fissura longitudinalis posterior. It forms a sheath for each of the filaments of the nerves, and for the nerves them- selves ; and, inferiorly, at the conical termination of the cord, is prolonged downwards as a slender ligament (filum terminate), which descends through the centre of the cauda equina, and is attached to the dura mater lining the canal of the coccyx. This attachment is a rudiment of the original extension of the spinal cord into the Canal of the sacrum and coccyx. The pia mater has, distributed to it, a number of nervous plexuses derived from the sympathetic. The Membrana dentata (ligamentum dentatum) is a thin process of pia mater sent off from each side of the cord throughout its entire length, and separating the anterior from the posterior roots of the spinal nerves. The number of serrations on each side is about twenty, the first being situated on a level with the occipital foramen, and having the vertebral artery and hypoglossal nerve passing in front and the spinal accessory nerve behind it, and the last opposite the first or second lumbar vertebra. Below this point, the membrana dentata is lost in the filum terminale of the pia mater. The use of this membrane is to maintain the position of the spinal cord in the midst of the fluid by wilich it is surrounded. The Spinal cord of the adult extends from the pons Varolii to opposite the first or second lumbar vertebra, where it terminates in a rounded point; in the child, at birth, it reaches to the middle of the third lumbar vertebra, and in the embryo is prolonged as far as the coccyx. It pre- sents a difference of diameter in different parts of its extent, and exhibits three enlargements. The uppermost of these is the medulla oblongata; the next corresponds with the origin of the nerves destined to the upper extremities; and the lower enlargement is situated n£ar its termination, * According to Mr. Rainey, these filaments are nervous fasciculi, having their origin in the arachnoid, and passing to the arteries of the cord. See page 371. SPINAL CORD. 391 Fig. 174* and corresponds with the attachment of the nerves which are intended for the supply of the lower limb. In form, the spinal cord is a flattened cylinder, and presents on its an- terior surface a fissure, which extends into the cord to the depth of one- third of its diameter. This is the fissura longitudinalis anterior. If the sides of the fissure be gently separated, they will be seen to be connected at the bottom by a layer of medullary substance, the anterior commissure. On the posterior surface another fissure exists, which is so narrow be- tween the second cervical and second lumbar nerve, as to be hardly per- ceptible. This is the fissura longitudinalis posterior. It extends more deeply into the cord than the anterior fissure, and terminates in the grey substance of the interior. These two fissures divide the medulla spinalis into tw7o lateral cords, which are connected to each other by the white commissure which forms the bottom of the anterior longitudinal fissure, and by a commissure of grey matter situated behind the former. On either side of the fissura longitudinalis posterior is a slight line which bounds on each side the posterior median columns. These columns are most appa- rent at the upper part of the cord, near the fourth ventricle, where they are separated by the point of the calamus scriptorius, and where they form the bulbous enlargement at each side, called processus clavatus. Two other lines are observed on the medulla, the anterior and posterior lateral sulci, cor- responding with the attach- ment of the anterior and poste- rior roots of the spinal nerves. The anterior lateral sulcus is a mere trace, marked only by the attachment of the filaments of the anterior roots. The pos- terior lateral sulcus is more evident, and is a narrow grey- ish line derived from the grey substance of the interior. Although these fissures and sulci indicate a division of the spinal cord into three pairs of columns, namely, anterior, lateral, and posterior, the posterior median columns being regarded as a part of the posterior co- lumns, it is customary to consider each half of the spinal cord as consist- ing of two columns only, the antero-lateral and the posterior. The antero- lateral columns are the columns of motion, and comprehend all that part of the cord situated between the fissura longitudinalis anterior and the posterior lateral sulcus, the grey line of origin of the posterior roots of the spinal nerves. The posterior columns are the columns of sensation. If a transverse section of the spinal cord be made, its internal structure may be seen and examined. It will then appear to be composed of two hollow cylinders of white matter, placed side by side, and connected by a narrow7 white commissure. Each cylinder is filled with grey substance, * Sections of the spinal marrow in different portions of its length. 1. Opposite the 11th dorsal vertebra. 2. Opposite the 10th dorsal. 3. Opposite the 8th dorsal. 4. Op- posite the 5th dorsal. 5. Opposite the 7th cervical. 6. Opposite the 4th cervical. 7. Opposite the 3d cervical. S. Section of medulla oblongata through the corpora oli varia. 392 CRANIAL NERVES. Fig. 175.* which is connected by a commissure of the u same matter. The form of the grey sub- stance, as observed in the section, is that of two irregularly curved lines joined by a transverse band. The extremities of the curved lines correspond to the sulci of origin of the anterior and posterior roots of the nerves. The anterior extremities, larger than the posterior, do not quite reach this surface ; but the posterior appear upon the surface, and form a narrow grey line, the sulcus lateralis posterior. The white substance of the spinal cord is composed of parallel fibres, which are collected into longitudinal laminae and extend throughout the entire length of the cord. These laminae are various in breadth, and are arranged in a radiated manner; one border being thick and corresponding with the surface of the cord, while the other is thin and lies in contact with the grey substance of the interior. According to Rolando the white substance constitutes a simple nervous membrane, which is folded into longitudinal plaits, having the radiated disposition above described. The anterior commissure, according to his description, is merely the continua- tion of this nervous membrane from one lateral cord across the middle line to the other. Moreover, Rolando considers that a thin lamina of pia mater is received between each of the folds from the exterior, while a layer of the grey substance is prolonged between them from within. Cruveil- hier is of opinion that each lamella is completely independent of its neigh- bours, and he believes this statement to be confirmed by pathology, which shows that a single lamella may be injured or atrophied, and at the same time be surrounded by others perfectly sound. CRANIAL NERVES. There are nine pairs of cranial nerves. Taken in their order from before, backwards, they are as follows: 1st. Olfactory. 2d. Optic. 3d. Motores oculorum. 4th. Pathetici (trochleares). 5th. Trifacial (trigemini). 6th. Abducentes. 7.1 ( Facial (portio dura, ( Auditory (portio mollis). * Sections of the spinal cord. After Arnold, a. A section made across the lower part of the corpora olivaria. 1, 1. Corpora pyramidalia. 2. Fissura longitudinalis an- terior. 3. The corpus olivare; in the section of which the zig-zag outline of the corpus dentatum is seen. 4. The corpus restiforme. 5. The grey substance of the corpus restiforme. 6. The corpora pyramidalia posteriora. 7. The floor of the fourth ven- tricle. b. A section made between the third and fourth cervical nerves. 1. The fissura longitudinalis anterior. 2. An indentation corresponding in situation with the fissura longitudinalis posterior, which latter is not distinguishable at this part of the spinal cord. 3, 3. The antero-lateral columns ofthe spinal cord. 4, 4. The posterior columns. 5, The anterior cornu of grey matter. 6. Its posterior cornu, terminating at 7, the sulcus lateralis posterior. 8. The isthmus connecting the grey matter of the two sides of the cord. OLFACTORY NERVE. 393 8th. Glosso-pharyngeal, Pneumogastric (vagus, par vagum). £ Spinal accessory. 9th. Hypoglossal (lingual). Functionally or physiologically the cranial nerves admit of division into three groups, namely, nerves of special sense, nerves of motion, and com- pound nerves, that is, nerves which contain fibres both of sensation and motion. The nerves belonging to these groups are the following: f 1st. Olfactory. Special sense.....^ 2d. Optic. [ 7th. Auditory. Motion Compound 3d. Motores oculorum. 4th. Pathetici. 6th. Abducentes. 7th. Facial. k 9th. Hypoglossal. 5th. Trifacial. 8th. Glosso-pharyngeal. Pneumogastric. Spinal accessory. The fourth, facial, and eighth nerves were considered by Sir Charles Bell to form a system apart from the rest, and to be allied in the functions of expression and respiration. In consonance with this view he termed them respiratory nerves, and he gave to that part of the medulla oblongata from which they arise the name of respiratory tract. Fig. 176* First pair. Olfactory. —The olfactory nerve arises by three roots ; an inner root from the substantia perforata, a middle root from a papil- la of grey matter (caruncu- la mammillaris), embedded in the anterior lobe, and an external root, which may be traced as a white streak along the fissure of Sylvius into the corpus striatum, where it is continuous with some of the fibres of the anterior com- missure. The nervous cord formed by the union of these three roots is soft in texture, prismoid m shape, and embedded in a sulcus between two convolutions on the under surface of each anterior lobe of the brain, lying between the pia mater and the arach- noid. As it passes forwards it increases in breadth and sw-ells at its extremity, * A view of the l«t pair or olfactory, with the nasal branches ofthe 5th. 1. Frontal sinu< 2 Sphenoidal sinus. 3. Hard palate. 4. Bulb of the olfactory nerve. 5. Branches ofthe olfactory on the superior and middle turbinated bones. 6. Spheno-pala- tine nerves from the 2d of the 5th. 7. Internal nasal nerve from the 1st ofthe 5th. 8. Branches of 7 to Schneiderian membrane. 9. Ganglion of Cloquet in the foramen inn- tivum 10 Anastomosis on the inferior turbinated bone of the branches ofthe 5th pair 394 OPTIC NERVE. Fig. 177* into an oblong mass of grey and white substance, the bulbus olfactorius, which rests upon the cribriform lamella of the ethmoid bone. From the under surface of the bulbous olfacto- ries are given off the nerves which pass through the cribriform foramina and supply the mucous membrane of the nares; they are arranged into two groups, an inner group, reddish in colour and soft, which spread out upon the septum narium, and an outer group, whiter and more firm, which descend through the bony ca- nals in the outer wall of the nares, and are distributed upon the superior and middle turbinated bones. Second pair. Optic.—The optic nerve, a nerve of large size, arises from the corpora geniculata on the posterior and inferior aspect of the thalamus opticus and from the nates. Proceeding from this origin it winds around the crus cerebri as a flattened band, under the name of tractus opticus, and joins with its fellow in front of the tuber cinereum to form the ovtic commissure (chiasma). The tractus opticus is united with the crus Fig. I78.t cerebri and tuber cinereum, and -p. is covered in by the pia mater; the commissure is also connected with the tuber cinereum, from w7hich it receives fibres, and the nerve beyond the commissure diverges from its fellow, becomes rounded in form, and is enclosed in a sheath derived from the arachnoid. In passing through the optic foramen the optic nerve receives a sheath from the dura mater, which splits at this point into two layers ; one, which be- comes the periosteum of the * A view of the 2d pair or optic, and the origins of seven other pairs. 1, 1. Globe of the eye, the one on the left hand is perfect, but that on the right has the sclerotic and choroid removed to show the retina. 2. The chiasm of the optic nerves. 3. The cor- pora albicantia. 4. The infundibulum. 5. The pons Varolii. 6. The medulla ob- longata. The figure is on the right corpus pyramidale. 7. The 3d pair, motores oculi. 8. 4th pair, pathetici. 9. 5th pair, trigemini. 10th. 6th pair, abducentes. 11. 7th pair, auditory and facial. 12th. 8th pair, pneumogastric, spinal accessory, and glosso-pha- ryngeal. 13. 9th pair, hypoglossal. t The isthmus encephali, showing the thalamus opticus, corpora quadrigemina, pons Varolii, and medulla oblongata, as viewed from the side. 1. The thalamus opticus. 2. The posterior prominence of this body, tuberculum superius posterius or pulvinar. 3. The corpus geniculatum externum. 4. The corpus geniculatum internum. 5. The commencement of the tractus opticus. 6. The pineal gland. 7. The nates. 8. The MOTORES OCULORUM—PATHETICI. 395 orbit; the other, the one in question, which forms a sheath for the nerve, and is lost in the sclerotic coat ofthe eyeball. After a short course within the orbit the optic nerve pierces the sclerotic and choroid coats and ex- pands into the nervous membrane of the eyeball, the retina. Near the globe, the nerve is pierced by a small artery, the arteria centralis retinae, which runs through the central axis of the nerve and reaches the internal surface of the retina, to which it distributes branches. The commissure rests upon the processus olivaris of the sphenoid bone; it is bounded by the lamina cinerea ofthe corpus callosum in front, by the substantia perforata on each side, and by the tuber cinereum behind. Within the commissure the innermost fibres of the optic nerves cross each other to pass to opposite eyes, while the outer fibres continue their course uninterruptedly to the eye of the corresponding side. The neurilemma of the commissure, as well as that of the nerves, is formed by the pia mater. Third pair. Motores Oculorum.—The motor oculi, a nerve of mo- derate size, arises from the inner side ofthe crus cerebri, close to the pons Varolii, and passes forward between the posterior cerebral and superior cerebellar'artery. It pierces the dura mater immediately in front of the posterior clinoid process ; descends obliquely along the external wall of the cavernous sinus; and divides into two branches which enter the orbit between the two heads of the external rectus muscle. The superior branch ascends, and supplies the superior rectus and levator palpebrae. The inferior sends a branch beneath the optic nerve to the internal rectus, another to the inferior rectus, and a long branch to the inferior oblique muscle. From the latter a short thick branch is given off to the ciliary ganglion, forming its inferior root. The fibres of origin of this nerve may be traced into the grey substance ofthe crus cerebri,* into the motor tract,f and as far as the superior fibres of the crus cerebri.! I*1 the cavernous sinus it receives one or two fila- ments from the cavernous plexus, and one from the ophthalmic nerve. Fourth Pair. Pathetici (trochlearis).—The fourth is the smallest cerebral nerve ; it arises from the valve of Vieussens close to the the testis, and winding around the crus cerebri to the extremity ofthe petrous portion of the temporal bone, pierces the dura mater near the oval opening for the testis of one side. 9. The brachium anterius of the corpora quadrigemina. a. The brachium posterius. b. The origin of the fourth nerve, which may be seen descending over the crus cerebri, c. The processus e cerebello ad testem, or superior peduncle of the cerebellum, d. The band of fibres termed laqueus, the superior division ofthe fas- ciculus olivaris crossing the superior peduncle of the cerebellum to enter the corpora quadrigemina. Through the small triangular space in front of this band, crossed by the fourth nerve, some ofthe fibres of the superior peduncle ofthe cerebellum may be seen. e. The superior portion of the crus cerebri, termed tegmentum. /. Its inferior portion, g. The third nerve, h. The pons Varolii, i. The crus cerebelli, or middle peduncle of the cerebellum, k. The inferior peduncle derived from the corpus resti- forme. The mass lying in the angular interval upon these is the superior peduncle. /. The fifth nerve issuing from between the transverse fasciculi ofthe pons Varolii, m. The sixth nerve, n. The seventh nerve; the inferior and smaller cord is the facial nerve the superior and larger the auditory, o. The corpus olivare crossed inferiorly by the superficial arciform fibres, p. The corpus pyramidale. q. The median poste- rior fasciculi of the medulla oblongata, r. The corpus restiforme. s. The spinal cord. t. The fourth ventricle. • Mayo. t Solly- * Grainger. 396 TRIFACIAL. fifth nerve, and passes along the outer wall of the cavernous sinus to the sphenoidal fissure. In its course through the sinus it is situated at first below the motor oculi, but afterwards ascends and becomes the highest of the nerves which enter the orbit through the sphenoidal fissure. Upon entering the orbit the nerve crosses the levator palpebrae muscle near its origin, and is distributed upon the orbital surface of the superior oblique or trochlearis muscle; hence its syno- nyn trochlearis. Branches.—While in the cavernous sinus the fourth nerve gives off a re- current branch, some filaments of communication to the ophthalmic nerve, and a branch to assist in forming the lachrymal nerve; the recurrent branch, which consists of sympathetic filaments derived from the carotid plexus, passes backwards between the layers of the tentorium, and divides into two or three filaments, which are distributed to the lining membrane of the lateral sinus. This nerve is sometimes a branch of the ophthalmic, and occasionally proceeds directly from the carotid plexus. Fifth Pair. Trifacial (trigeminus).—The fifth nerve, the great sen- sitive nerve of the head and face, and the largest cranial nerve, is analogous to the spinal nerves in its origin by two roots, from the anterior and pos- terior columns of the spinal cord, and in the existence of a ganglion on the posterior columns of the spinal cord, and in the existence of a ganglion on the posterior root. It arises! from a tract of yellowish-white matter situated in front of the floor of the fourth ventricle and the origin of the auditory nerve, and behind the crus cerebelli. This tract divides inferiorly into two fasciculi which may be traced downwards into the spinal cord, one being continuous with the fibres of the anterior column, the other with the posterior column. Proceeding from this origin the two roots ofthe nerve pass forward, and issue from the brain upon the anterior part of the crus cerebelli, where they are separated by a slight interval. The anterior is much smaller than the posterior, and the two together constitute the fifth nerve, which in this situation consists of seventy to a hundred filaments held together by pia mater. The nerve then passes through an oval opening in the border of the tentorium, near the extremity of the petrous bone, and spreads out into a large semilunar ganglion, the Casserian. If the ganglion be turned over, it will be seen that the anterior root lies against its under * A view ofthe 3d, 4th, and 6th pairs of nerves. 1. Ball ofthe eye, the rectus exter- nus muscle being cut and hanging down from its origin. 2. The superior maxilla. 3. The third pair or motor oculi distributed to all the muscles ofthe eye except the supe- rior oblique and external rectus. 4. The 4th pair or patheticus going to the superior oblique muscle. 5. One ofthe branches of the 5th. 6. The 6th pair cr motor externus distributed to the external rectus muscle. 7. Spheno-palatine ganglion and branches. 8. Ciliary nerves from the lenticular ganglion, the short root of which is seen to connect it with the 3d pair. 11 have adopted the origin of this nerve, given by Dr. Alcock, of Dublin, as the result of his directions, in the Cyclopaedia of Anatomy and Physiology. Mr. Mayo also traces the anterior root of the nerve to a similar origin. Fig. 179* OPHTHALMIC NERVE. 397 surface without having any connexion with it, and may be followed onwards to the inferior maxillary nerve. The Casserian ganglion divides into three branches, the ophthalmic, superior maxillary, and inferior maxillary. The Ophthalmic Nerve is a short trunk, being not more than three quarters of an inch in length; it arises from the upper angle of the Casse- rian ganglion, beneath the dura mater, and passes forwards through the outer wall of the cavernous sinus, lying externally to the other nerves; it divides into three branches. Previously to its division it receives several filaments from the carotid plexus, and gives off a small recurrent nerve, that passes backwards with the recurrent branch of the fourth nerve between the two layers of the tentorium to the lining membrane of the lateral sinus. The Branches ofthe ophthalmic nerve are, the— Frontal, Lachrymal, Nasal. Fig. 180.* The Frontal nerve mounts above the levator palpebral, and runs for- ward, resting upon that muscle, to the supra-orbital foramen, through which it escapes upon the forehead, with the supra-orbital artery. It sup- plies the conjunctiva and upper eyelid, and the integument of the cranium as far as the vertex. The frontal nerve gives off but one small branch, the supra-trochlear, which passes inwards above the pulley of the superior oblique muscle, and ascends along the middle line of the forehead, distributing filaments to the integument, to the inner angle of the eye and root of the nose, and to the conjunctiva. The Lachrymal nerve, the smallest of the three branches of the ophthal- mic, receives a filament from the fourth nerve in the cavernous sinus, and passes outwards along the upper border of the external rectus muscle, and in company with the lachrymal artery, to the lachrymal gland, where it divides into two branches. The superior branch passes along the upper surface of the gland and through a foramen in the malar bone, and is distributed upon the temple and cheek, communicating with the subcutaneus malse and facial nerves. The inferior branch supplies the lower surface of the gland and con- junctiva, and terminates in the integu- ment of the upper lid communicating with the facial nerve. The Nasal nerve (naso-ciliaris) passes forwards between the two heads of the external rectus muscle, crosses the optic nerve in company with the ophthalmic artery, and enters the anterior ethmoidal foramen immediately above the internal rectus. It then traverses the upper part of the ethmoid bone to the cribriform plate, and passes downwards through the slit-like opening by the side of the * A view of the distribution of the trifacial or 5th pair.—1. Orbit. 2. Antrum of High- more. 3. Tongue. 4. Lower maxilla. 5. Root of 5th pair forming the ganglion of Casser. 6. 1st branch, Ophthalmic. 34 7. 2d branch, Superior maxillary. 8. 3d branch, 398 SUPERIOR MAXILLARY NERVE. crista galli into the nose, where it divides into two branches—an internal branch supplying the mucous membrane, near the anterior openings of the nares; and an external branch w7hich passes between the fibro-cartilages, and is distributed to the integument at the extremity of the nose. The Branches of the nasal nerve within the orbit are, the ganglionic, ciliary, and infra-trochlear; in the nose it gives off one or two filaments to the anterior ethmoidal cells and frontal sinus. The ganglionic branch passes obliquely forwards to the superior angle of the ciliary ganglion, forming its superior long root. The ciliary branches are two or three fila- ments which are given off by the nasal as it crosses the optic nerve. They pierce the posterior part of the sclerotic, and pass between that tunic and the choroid to be distributed to the iris. The infra-trochlear is given off just as the nerve is about to enter the anterior ethmoidal foramen. It passes along the superior border of the internal rectus to the inner angle of the eye, where it communicates with the supra-trochlear nerve, and supplies the lachrymal sac, caruncula lachrymalis, conjunctiva, and inner angle of the orbit. The Superior Maxillary Nerve, larger than the preceding, proceeds from the middle of the Casserian ganglion ; it passes forwards through the foramen rotundum, crosses the spheno-maxillary fossa, and enters the canal in the floor of the orbit, along which it runs to the infra-orbital fora- men. Emerging on the face, beneath the levator labii superioris muscle, it divides into a number of branches, which are distributed to the lower eyelid and conjunctiva, and to the muscles and integument of the upper lip, nose, and cheek, forming a plexus with the facial nerve. The Branches of the superior maxillary nerve are divisible into three groups: — 1. Those which are given off in the spheno-maxillary fossa. 2. Those in the infra-orbital canal; and 3. Those on the face. They may be thus arranged: C Orbital, Spheno-maxillary fossa, < Two from Meckel's ganglion, ( Posterior dental. T r. ,., , , { Middle dental, Infra-orbital canal, \ A , . , , ', J ( Anterior dental. r, .7 /. S Muscular, On the face, { n . ' J ' ( Cutaneous. The Orbital branch (n. subcutaneus malae) enters the orbit through the spheno-maxillary fissure, and divides into two branches, temporal and malar; the temporal branch ascends along the outer wall ofthe orbit, and, after receiving a branch from the lachrymal nerve, passes through a canal Inferior maxillary. 9. Frontal branch, dividing into external and internal frontal at 14. 10. Lachrymal branch, dividing before entering the lachrymal gland. 11. Nasal branch. Just under the figure is the long root of the lenticular or ciliary ganglion, and a few of the ciliary nerves. 12. Internal nasal, disappearing through the anterior ethmoidal fora- men. 13. External nasal. 14. External and internal frontal. 15. Infra-orbitary nerve. 16. Posterior dental branches. 17. Middle dental branch. 18. Anterior dental nerve. 19. Terminating branches of infra-orbital, called labial and palpebral. 20. Subcutaneus mate or orbitar branch. 21. Pterygoid or recurrent, from Meckel's ganglion. 22. Five anterior branches of 3d of 5th, being nerves of motion, and called masseter, temporal, pterygoid and buccal. 23. Lingual branch joined at an acute angle by the chorda tym- pani. 24. Inferior dental nerve terminating in, 25. Mental branches. 2G. Superficial emporal nerve. 27. Auricular branches. 28. Mylo-hyoid branch. INFERIOR MAXILLARY NERVE. 399 in the malar bone and enters the temporal fossa; it then pierces the tem- poral muscle and fascia and is distributed to the integument ofthe temple and side of the forehead, communicating with the facial and anterior auricular nerve. In the temporal fossa it communicates with the deep temporal nerves. The malar, or inferior branch, takes its course along the lower angle of the outer wall of the orbit, and emerges upon the cheek through an opening in the malar bone, passing between the fibres of the orbicularis palpebrarum muscle. It communicates with branches of the infra-orbital and facial nerves. The Two branches from Meckel's ganglion ascend from that body to join the nerve, as it crosses the spheno-maxillary fossa. The Posterior dental branches pass through small foramina, in the posterior surface of the superior maxillary bone, and running forwards in the base of the alveolus, supply the posterior teeth and gums. The Middle and anterior dental branches descend to the corresponding teeth and gums; the former beneath the lining membrane of the antrum, the latter through distinct canals in the walls of the bone. Previously to their distribution, the dental nerves form a plexus (superior maxillary plexus) in the outer wall of the superior maxillary bone immediately above the alveolus. From this plexus the filaments are given off which supply the pulps ofthe teeth, the gums, the mucous membrane ofthe floor ofthe nares, and the palate. Some gangliform masses have been described in connexion with this plexus, one being placed over the canine, and another over the second molar tooth. The Muscular and cutaneous branches are the terminating filaments of the nerve; they supply the muscles, integument, and mucous membrane of the cheek, nose, and lip, and form an intricate plexus with branches ofthe facial nerve. The Inferior Maxillary Nerve proceeds from the inferior angle of the Casserian ganglion ; it is the largest of the three divisions of the fifth nerve, and is augmented in size by the anterior or motor root, which passes behind the ganglion, and unites with the inferior maxillary as it escapes through the foramen ovale. Emerging at the foramen ovale the nerve divides into two trunks, external and internal, which are separated from each other by the external pterygoid muscle. The External trunk, into which may be traced nearly the whole of the motor root, immediately divides into five branches which are distributed to the muscles of the temporo-maxillary region ; they are— The Masseteric, which crosses the sigmoid notch with the masseteric artery to the masseter muscle. It sends a small branch to the temporal muscle, and a filament to the temporo-maxillary articulation. Temporal; two branches passing betw-een the upper border of the ex- ternal pterygoid muscle and the temporal bone to the temporal muscle. Two or three filaments from these nerves pierce the temporal fascia, and communicate with the lachrymal, subcutaneous malae, auricular and facial nerve. Buccal; a large branch which pierces the fibres of the external ptery- goid to reach the buccinator muscle. This nerve sends filaments to the temporal and external pterygoid muscle, to the mucous membrane and integument of the cheek, and communicates with the facial nerve. 400 INFERIOR DENTAL NERVE. Internal pterygoid; a long and slender branch, which passes inwards to the internal pterygoid muscle, and gives filaments in its course to the tensor palati and tensor tympani. This nerve is remarkable from its con- nexion with the otic ganglion, to which it is attached. The Internal trunk divides into three branches— Gustatory, Inferior dental, Anterior auricular. The Gustatory Nerve descends between the two pterygoid muscles to the side of the tongue, where it becomes flattened, and divides into numerous filaments, which are distributed to the papillae and mucous membrane. Relations. — It lies at first between the external pterygoid muscle and the pharynx, next between the two pterygoid muscles, then between the internal pterygoid and ramus of the jaw, and between the stylo-glossus muscle and the submaxillary gland; lastly, it runs along the side of the tongue, resting upon the hyo-glossus muscle, and covered in by the mylo- hyoideus and mucous membrane. The gustatory nerve, w7hile between the two pterygoid muscles, receives a branch from the inferior dental; lower down it is joined at an acute angle by the chorda tympani which passes downwards in the sheath of the gustatory to the submaxillary gland, where it unites with the submaxillary ganglion. On the hyo-glossus muscle some branches of communication are sent to the hypoglossal, and in the course of the nerve several small branches to the mucous membrane of the fauces, to the tonsils, submaxil- lary gland, Wharton's duct, and sublingual gland. The Inferior Dental Nerve passes downwards with the inferior den- tal artery, at first between the two pterygoid muscles, and then between the internal lateral ligament and the ramus ofthe lower jaw, to the dental foramen. It then runs along the canal in the inferior maxillary bone, distributing branches (inferior maxillary plexus) to the teeth and gums, and divides into two terminal branches, incisive and mental. The incisive branch passes forwards, to supply the incisive teeth: the mental branch escapes through the mental foramen, to be distributed to the muscles and integument ofthe chin and lowrer lip, and to the raucous membrane ofthe latter, communicating with the facial nerve. The inferior dental nerve gives off but one branch, the mylo-hyoidean, which leaves the nerve just as it is about to enter the dental foramen. This branch pierces the insertion of the internal lateral ligament, and de scends along a groove in the bone to the inferior surface of the mylo- hyoid muscle, to which, and to the anterior belly of the digastricus, it is distributed. The Anterior Auricular Nerve originates by two roots, between which the arteria meningea media takes its course, and passes directly backw-ards behind the articulation of the lower jaw, against which it rests. In this situation it divides into two branches, which reunite, and form a kind of plexus. From the plexus two branches are given off—ascending and descending. The ascending or temporal branch sends one or two considerable branches of communication to the facial nerve, and then ascends in front of the ear to the temporal region, upon which it is distri FACIAL NERVE. 401 buted in company with the branches of the temporal artery. In its course it sends filaments to the temporo-maxillary articulation, to the pinna and meatus of the ear, and to the integument in the temporal region. It com- municates on the temple with branches of the facial, supra-orbital, lachry- mal, and subcutaneus mala; nerve. The descending branch enters the parotid gland, to which it sends numerous branches; it communicates with the inferior dental and auricularis magnus nerve, and supplies the external ear, the meatus auditorius, and the temporo-maxillary articulation, and sends one or two filaments into the tympanum. Sixth Pair. Abducentes.—The abducens nerve, about half the size of the motor oculi, arises by several filaments from the upper constricted part of the corpus pyramidale close to the pons Varolii. Proceeding for- wards from this origin it lies parallel with the basilar artery, and, piercing the dura mater upon the clivus Blumenbachii of the sphenoid bone, ascends beneath that membrane to the cavernous sinus. It then runs forwards along the inner wall of the sinus below the other nerves, and, resting against the internal carotid artery, passes between the two heads of the external rectus, and is distributed to that muscle. As it enters the orbit, it lies upon the ophthalmic vein, from which it is separated by a lamina of dura mater. In the cavernous sinus it is joined by several filaments from the carotid plexus, by one from Meckel's ganglion, and one from the ophthalmic nerve. Mr. Mayo traced the origin of this nerve between the fasciculi of the corpora pyramidalia to the posterior part of the medulla oblongata; and Mr. Grainger pointed out its connexion with the grey substance of the spinal cord. Seventh Pair.—The seventh pair consists of two nerves which lie side by side on the posterior border of the crus cerebelli. The smaller and g-1 most internal of these, and, at the same time, the most dense in tex- ture, is the facial nerve or portio dura. The external nerve, which is soft and pulpy, and often grooved by contact with the preceding, is the auditory nerve or portio mollis of the seventh pair. Soemmering makes the auditory nerve the eighth pair; but, retaining the classifica- tion of Willis, we regard it as a part of the seventh with the facial. Facial Nerve (portio dura). —The facial nerve arises from the upper part of the groove between the corpus olivare and corpus restiforme, close to the pons Varolii, from which point its fibres may be traced deeply into the corpus restiforme. The nerve then passes forwards, resting upon the * A view of the origin and distribution of the portio mollis of the 7th pair or auditory nerve 1 The medulla oblongata. 2. The pons Varolii. 3 and 4. The crura cerebelli of the richt -ide 5. 8th pair. 6. 9th pair. 7. The auditory nerve distributed to the cochlea and labyrinth. 8. The 6th pair. 9. The portio dura of the 7th pair. 10. The 4th pair. 11 The 3d pair. 34* 2a 402 FACIAL NERVE. crus cerebelli, and comes into relation with the auditory nerve, with which it enters the meatus auditorius internus, lying at first to the inner side of, and then upon that nerve. At the bottom of the meatus it enters the canal expressly intended for it, the aqueductus Fallopii, and directs its course forwards towards the hiatus Fallopii, where it forms a gangliform swelling (intumescentia gangliformis), and receives the petrosal branch ofthe Vidian nerve. It then curves backwards towards the tympanum, and descends along the inner wall of that cavity to the stylo-mastoid foramen. Emerg- ing at the stylo-mastoid foramen it passes forwards within the parotid gland, crossing the external jugular vein and external carotid artery, and at the ramus of the lower jaw divides into two trunks, temporo-facial and cervico-facial. These trunks at once split into numerous branches, which, after forming a number of looped communications (pes anserinus) with each other over the masseter muscle, spread out upon the side of the face, from the temple to the neck, to be distributed to the muscles of this exten- sive region. The communications which the facial nerve maintains in its course are the following: in the meatus auditorius, it sends one or two filaments to the auditory nerve ; the intumescentia gangliformis receives the nervus petrosus superficialis major and minor, and sends a twig back to the auditory nerve; behind the tympanum the nerve receives one or twro twigs from the auricular branch of the pneumogastric; at its exit from the stylo-mastoid foramen it receives a twig from the glosso-pharyngeal, and in the parotid gland one or two large branches from the anterior auricular nerve. Besides these, the facial nerve has numerous peripheral communications, with the branches of the fifth nerve on the face, and of the cervical nerves in the parotid gland and neck. The numerous com- munications of the facial nerve obtained for it the designation of nervus sympatheticus minor. The Branches of the facial nerve are— Within, the aqueductus { Tympanic, Fallopii, ( Chorda tympani. After emerging at the \ ^^J^0"^' stylo-mastoid foramen, j^? ~ < ' J J ' ( Digastric. On the face, j Temporo-facial, J ' { Cervico-facial. The Tympanic branch is a small filament distributed to the stapedius muscle. The Chorda tympani quits the facial just before that nerve emerges from the stylo-mastoid foramen, and ascends by a distinct canal to the upper part of the posterior wall of the tympanum, where it enters that cavity through an opening situated between the base of the pyramid and the attachment of the membrana tympani, and becomes invested by mu cous membrane. It then crosses the tympanum between the handle of the malleus and long process of the incus to the anterior inferior angle of the cavity, and escapes through a distinct opening in the fissura Glaseri, and joins the gustatory nerve at an acute angle between the two pterygoid muscles. Enclosed in the sheath of the gustatory nerve, it descends to the submaxillary gland, where it unites with the submaxillary ganglion. The Posterior auricular nerve ascends behind the ear, between the AUDITORY NERVE. 403 182* meatus and mastoid process, and divides into an anterior and a poste- rior branch. The anterior branch receives a filament of communication from the auricular branch of the pneumogastric nerve, and distributes filaments to the re- trahens and attollens aurem muscles and to the pinna. The posterior branch commu- nicates with the auricularis magnus and occipitalis minor, and is distributed to the poste- rior belly of the occipito-fron- talis. The Stylo-hyoid branch is distributed to the stylo-hyoid muscle. The Digastric branch sup- plies the posterior belly of the digastricus muscle, and com- municates with the glosso- pharyngeal and pneumogastric nerve. The Temporo-facial gives off a number of branches, w-hich are distri- buted over the temple and upper half of the face, supplying the muscles of this region, and communicating with the branches of the auricular, the subcutaneus maloe, and the supra-orbital nerve. The inferior branches, which accompany Stenon's duct, and form a plexus with the terminal branches of the infra-orbital nerve. The Cervico-facial divides into a number of branches that are distri- buted to muscles on the lower half of the face and upper part of the neck. The cervical branches form a plexus with the superficialis colli nerve over the submaxillary gland, and are distributed to the platysma myoides. Auditory Nerve (portio mollis). — The auditory nerve takes its origin in the lineae transversa; (striae medullares) of the anterior wrall or floor of the fourth ventricle, and w-inds around the corpus restiforme, from which it receives fibres, to the posterior border of the crus cerebelli. It then passes forwards upon the crus cerebelli in company with the facial nerve, which lies in a groove on its superior surface, and enters the meatus * The distribution of the facial nerve and the branches ofthe cervical plexus. 1. The facial nerve, escaping from the stylo-mastoid foramen, and crossing the ramus of the lower jaw ; the parotid gland has been removed in order to see the nerve more dis- tinctly. 2. The posterior auricular branch; the digastric and stylo-mastoid filaments are seen near the origin of this branch. 3. Temporal branches, communicating with (4) the branches of the frontal nerve. 5. Facial branches, communicating with (6) the infra-orbital nerve. 7. Facial branches, communicating with (8) the mental nerve. 9. Cervico-facial branches, communicating with (10) the superficialis colli nerve, and forming a plexus (11) over the submaxillary gland. The distribution of the branches of the "facial in a radiated direction over the side of the face and their looped commu- nications constitute the pes anserinus. 12. The auricularis magnus nerve, one of the ascending branches of the cervical plexus. 13. The occipitalis minor, ascending along the posterior border of the sterno-mastoid muscle. 14. The superficial and deep de- scending branches of the cervical plexus. 15. The spinal accessory nerve, giving off a branch to the external surface ofthe trapezius muscle. 16. The occipitalis major nerve, the posterior branch of the second cervical nerve. 404 GLOSSO-PHARYNGEAL nerve. auditorius internus, and at the bottom of the meatus it divides into two branches, cochlear and vestibular. The auditory nerve is soft and pulpy in texture, and receives in the meatus auditorius several filaments from the facial nerve. Eighth Pair. — The eighth pair consists of three nerves, glosso- pharyngeal, pneumogastric, and spinal accessory; these are the ninth, tenth, and eleventh pairs of Soemmering. Glosso-pharyngeal Nerve. — The glosso-pharyngeal nerve arises by five or six filaments from the groove between the corpus olivare and resti- forme, and escapes from the skull at the innermost extremity of the jugular foramen through a distinct opening in the dura mater, lying anteriorly to the sheath ofthe pneumogastric and spinal accessory nerves, and internally to the jugular vein. It then passes forwards between the jugular vein and internal carotid artery, to the stylo-pharyngeus muscle, and descends along the inferior border of that muscle to the hyo-glossus, beneath which it curves to be distributed to the mucous membrane of the base of the tongue and fauces, to the mucous glands of the mouth, and to the tonsils. While situated in the jugular fossa, the nerve presents tw7o gangliform swellings; one superior (ganglion jugulare of Midler) of small size, and involving only the posterior fibres of the nerve ; the other inferior, nearly- half an inch below the preceding, of larger size and occupying the whole diameter of the nerve, the ganglion of Andersch* (ganglion petrosum). The fibres of origin of this nerve may be traced through the fasciculi of the corpus restiforme to the grey substance in the floor of the fourth ventricle. The Branches of the glosso-pharyngeal nerve are— Communicating branches with the Facial, Pneumogastric, Spinal accessory, Sympathetic. Tympanic, Muscular, Pharyngeal, Lingual, Tonsillitic. The Branches of communication proceed from the ganglion and from the upper part of the trunk of the nerve, and are common to the facial, eighth pair, and sympathetic; they form a complicated plexus at the base of the skull. The Tympanic branch (Jacobson's nerve) proceeds from the ganglion of Andersch, or from the trunk of the nerve immediately above the gan- glion: it enters a small bony canal in the jugular fossa (page 68) and divides into six branches, which are distributed upon the inner wall ofthe tympanum, and establish a plexiform communication (tympanic plexus) with the sympathetic and fifth pair of nerves. The branches of distribu- tion supply the fenestra rotunda, fenestra ovalis, and Eustachian tube: those of communication join the carotid plexus, the petrosal branch of the Vidian nerve, and the otic ganglion. * Charles Samuel Andersch. " Tractatus Anatomico-Physiologicus de Nervis Cor poris Humani Aliquibus, 1797." PNEUMOGASTRIC NERVE. 405 The Muscular branch divides into filaments, which are distributed to the stylo-pharyngeus and to the posterior belly of the digastricus and stylo-hyoideus muscle. The Pharyngeal branches are two or three filaments which are distri- buted to the pharynx and unite with the pharyngeal branches of the pneu- mogastric and sympathetic nerve to form the pharyngeal plexus. The Lingual branches enter the substance of the tongue beneath the hyo-glossus and stylo-glossus muscle, and are distributed to the mucous membrane of the side and base of the tongue, and to the epiglottis and fauces. The Tonsillitic branches proceed from the glosso-pharyngeal nerve near its termination ; they form a plexus (circulus tonsillaris) around the base of the tonsil, from which numerous filaments are given off to the mucous membrane ofthe fauces and soft palate, communicating with the posterior palatine branches of Meckel's ganglion. Pneumogastric Nerve (vagus).—The pneumogastric nerve arises by ten or fifteen filaments from the groove between the corpus olivare and corpus restiforme, immediately below the glosso-pharyngeal, and passes out of the skull through the inner extremity of the jugular foramen in a distinct canal of the dura mater. While situated in this canal it presents a small rounded ganglion (ganglion jugulare); and having escaped from the skull, a gangliform swelling (plexus gangliformis), nearly an inch in length,- and surrounded by an irregular plexus of white nerves, which commuuicate with each other, with the other divisions of the eighth pair, and with the trunk of the pneumogastric below7 the ganglion. The plexus gangliformis (ganglion of the superior laryngeal branch, of Sir Astley Cooper,) is situated, at first, behind the internal carotid artery, and then between that vessel and the internal jugular vein. The pneumogastric nerve then descends the neck within the sheath of the carotid vessels, lying behind and between the artery and vein, to the root of the neck. Here the course of the nerve at opposite sides becomes different. On the right side it passes betw-een the subclavian artery and vein to the posterior mediastinum, then behind the root of the lung to the oeso- phagus, which it accompanies to the stomach, lying on its posterior aspect. On the left it enters the chest parallel with the left subclavian artery, crosses the arch of the aorta, and descends behind the root of the lung, and along the anterior surface of the oesophagus, to the stomach. The fibres of origin of the pneumogastric nerve, like those of the glosso- pharyngeal, may be traced through the fasciculi of the corpus restiforme into the grey substance of the floor of the fourth ventricle. The Branches of the pneumogastric nerve are the following :— Communicating branches with the Facial, Glosso-pharyngeal, Spinal accessory, Hypo-glossal, Sympathetic. Auricular, Pharyngeal, Superior laryngeal, 406 SUPERIOR LARYNGEAL NERVE. Cardiac, Inferior or recurrent laryngeal, Pulmonary anterior, Pulmonary posterior, Oesophageal, Gastric. Fig. 183* The Branches of communication form part ofthe complicated plexus at the base of the skull. The branches to the ganglion of Andersch are given off by the superior ganglion in the jugular fossa. The Auricular nerve is given off from the lower part of the jugular ganglion, or from the trunk of the nerve immediately below, and re- ceives immediately after its origin a small branch of communication from the glosso-pharyngeal. It then passes outwards behind the jugular vein, and on the outer side of that vessel enters a small canal (page 68) in the petrous portion of the temporal bone near the stylo-mastoid foramen. Guided by this canal it reaches the descending part ofthe aqueductus Fallopii and joins the fa- cial nerve. In the aqueductus Fallopii the auri- cular nerve gives off two small filaments, one of which communicates with the posterior auricular branch of the facial, while the other is distri- buted to the pinna. The Pharyngeal nerve arises from the pneu- mogastric, immediately above the gangliform plexus, and descends behind the internal carotid artery to the upper border of the middle constric- tor, upon which it forms the pharyngeal plexus assisted by branches from the glosso-pharyngeal, superior laryngeal, and sympathetic. The pha- ryngeal plexus is distributed to the muscles and mucous membrane of the pharynx. The Superior laryngeal nerve arises from the gangliform plexus of the pneumogastric, of which it appears to be almost a continuation; hence this plexus was named by Sir Astley Cooper the " ganglion of the superior laryngeal branch.'''' The nerve descends behind the internal carotid artery to the opening in the thyro-hyoidean mem brane, through which it passes with the superior laryngeal artery, and is distributed to the mucous membrane ofthe larynx and arytenoideus muscle. On the latter, and behind the cricoid cartilage, * Origin and distribution of the eighth pair of nerves. 1, 3, 4. The medulla oblongata. 1 Is the corpus pyramidale of one side. 3. The corpus olivare. 4. The corpus resti- forme. 2. The pons Varolii. 5. The facial nerve. 6. The origin ofthe glosso-pharyn- geal nerve. 7. The ganglion of Andersch. 8. The trunk of the nerve. 9. The spinal accessory nerve. 10. The ganglion ofthe pneumogastric nerve. 11. Its plexiform gan- INFERIOR LARYNGEAL NERVE. 407 it communicates with the recurrent laryngeal nerve. Behind the internal carotid it gives off the external laryngeal branch, which sends a twig to the pharyngeal plexus, and then descends to supply the inferior constrictor and crico-thyroid muscles and thyroid gland. This branch communicates inferiorly with the recurrent laryngeal and sympathetic nerve. Mr. Hilton of Guy's Hospital, concludes from his dissections* that the superior laryngeal nerve is the nerve of sensation to the larynx, being dis- tributed solely (with the exception of its external laryngeal branch and a twig to the arytenoideus) to the mucous membrane. If this fact be taken in connexion with the observations of Sir Astley Cooper, and the dissec- tions of the origin of the nerve by Mr. Edward Cock, we shall have ample evidence, both in the ganglionic origin of the nerve and in its distribution, of its sensitive function. The recurrent, or inferior laryngeal nerve, is the proper motor nerve of the larynx, and is distributed to its muscles. The Cardiac branches, two or three in number, arise from the pneumo- gastric in the lower part of the neck, and cross the lower part of the com- mon carotid, to communicate with the cardiac branches of the sympathetic, and with the great cardiac plexus. The Recurrent laryngeal, or inferior laryngeal nerve, curves around the subclavian artery on the right, and the arch of the aorta on the left side. It ascends in the groove between the trachea and oesophagus, and piercing the lower fibres of the inferior constrictor muscle enters the larynx close to the articulation ofthe inferior cornu ofthe thyroid with the cricoid car- tilage. It is distributed to all the muscles of the larynx with the excep- tion of the crico-thyroid, and communicates on the arytenoideus muscle with the superior laryngeal nerve. As it curves around the subclavian artery and aorta it gives branches to the heart and root of the lungs ; and as it ascends the neck it distributes filaments to the oesophagus and tra- chea, and communicates with the external laryngeal nerve and sympa- thetic. The Anterior pulmonary branches are distributed upon the anterior as- pect of the root of the lungs, forming, with branches from the great car- diac plexus, the anterior pulmonary plexus. The Posterior pulmonary branches, more numerous than the anterior, are distributed upon the posterior aspect of the root of the lungs, and are joined by branches from the great cardiac plexus, forming the posterior pulmonary plexus. Upon the oesophagus the two nerves divide into numerous branches, which communicate with each other and constitute the oesophageal plexus which completely surrounds the cylinder ofthe oesophagus, and accompa- nies it to the cardiac orifice of the stomach. The Gastric branches are the terminal filaments of the two pneumogas- tric nerves; they are spread out upon the anterior and posterior surfaces ofthe stomach, and are likewise distributed to the omentum, spleen, pan- creas, liver, and gall-bladder, and communicate, particularly the right nerve, with the solar plexus. n 12 Its trunk 13. Its pharyngeal branch forming the pharyngeal plexus (14), sted bv a branch from the glosso-pharyngeal (8), and one from the superior laryn- ncrve (15) 16 Cardiac branches. 17. Recurrent laryngeal branch. 18. Anterior pulmonary branches. 19. Posterior pulmonary branches. 20. Esophageal plexus^ 21. Gatric branches 22. Origin of the spinal accessory nerve. 23. Its branches distri- buted to the sterno-mastoid muscle. 24. Its branches to the trapezius muscle. * Guy's Hospital Reports, vol. ii. glion assiste geal 408 HYPOGLOSSAL NERVE. Spinal Accessory Nerve. — The spinal accessory nerve arises by several filaments from the side of the Fig. 184 * spinal cord as low down as the fourth or fifth cervical nerve, and ascends behind the ligamentum denticulatum, and between the anterior and poste- rior roots of the spinal nerves, to the foramen lacerum posterius. It com- municates in its course with the pos- terior root of the first cervical nerve, and entering the foramen lacerum becomes applied against the poste- rior aspect of the ganglion jugulare of the pneumogastric, being con- tained in the same sheath of dura mater. In the jugular fossa it di- vides into two branches; the smaller joins the pneumogastric immediately below the jugular ganglion, and con- tributes to the formation of the pha- ryngeal nerve; the larger or true continuation of the nerve passes backwards behind the internal jugu- lar vein, and descends obliquely to the upper part of the sterno-mastoid muscle. It pierces the sterno-mastoid, and then passes obliquely across the neck, communicating with the second, third, and fourth cervical nerves, and is distributed to the trapezius. The spinal accessory sends numerous twigs to the sterno-mastoid in its passage through that muscle, and in the trapezius the nervous filaments may be traced downwards to its lower border. The pneumogastric and spinal accessory nerves together (nervus vagus cum accessorio) resemble a spinal nerve, of which the former with its ganglion is the posterior and sensitive root, the latter the anterior and motor root. Ninth Pair.| Hypoglossal Nerve (lingual). The hypoglossal nerve arises from the groove between the corpus pyramidale and corpus olivare * The anatomy of the side ofthe neck, showing the nerves ofthe tongue. 1. A frag- ment ofthe temporal bone containing the meatus auditorius externus, mastoid, and sty- loid process. 2. The stylo-hyoid muscle. 3. The stylo-glossus. 4. The stylo-pharyn- geus. 5. The tongue. 6. The hyo-glossus muscle; its two portions. 7. The genio-hyo- glossus muscle. 8. The genio-hyoideus; they both arise from the inner surface of the symphysis of the lower jaw. 9. The sterno-hyoid muscle. 10. The sterno-thyroid. 11. The thyro-hyoid, upon which the thyro-hyoidean branch ofthe hypoglossal nerve is seen ramifying. 12. The omo-hyoid crossing the common carotid artery (13), and in- ternal jugular vein (14). 15. The external carotid giving off its branches. 16. The internal carotid. 18. The gustatory nerve giving off a branch to the submaxillary gan- glion (18), and communicating a little further on with the hypoglossal nerve. 19. The submaxillary, or Wharton's duct, passing forwards to the sublingual gland. 20. The glosso-pharyngeal nerve, passing in behind the hyo-glossus muscle. 21. The hypoglos- sal nerve curving around the occipital artery. 22. The descendens noni nerve, form- ing a loop with (23) the commupicans noni; which is seen to be arising by fila- ments from the upper cervical nerves. 24. The pneumogastric nerve, emerging from between the internal jugular vein and common carotid artery, and entering the chest. 25. The facial nerve, emerging from the stylo-mastoid foramen, and crossing the exter- nal carotid artery. t The twelfth pair according to the arrangement of Soemmering. SPINAL NERVES. 409 by ten or fifteen filaments, which being collected into two bundles, escape from the cranium through the anterior condyloid foramen. The nerve then passes forwards between the internal carotid artery and internal jugu- lar vein, and descends along the anterior and inner side of the vein to a point parallel with the angle of the lower jaw. It next curves inwards around the occipital artery, with which it forms a loop, and crossing the lower part of the hyo-glossus muscle to the genio-hyo-glossus, sends fila- ments onwards with the anterior fibres of that muscle as far as the tip of the tongue. It is distributed to the muscles of the tongue, and principally to the genio-hyo-glossus. While resting on the hyo-glossus muscle it is flattened, and beneath the mylo-hyoideus it communicates with the gusta- tory nerve. At its origin the hypoglossal nerve sometimes communicates with the posterior root of the first cervical nerve. The Branches of the hypoglossal nerve are: Communicating branches with the Pneumogastric, Spinal accessory, First and second cervical nerves, Sympathetic. Descendens noni, Thyro-hyoidean branch, Communicating filaments with the gustatory nerve. The Communications with the pneumogastric and spinal accessory take place through the medium of a plexiform interlacement of branches at the base of the skull, behind the internal jugular vein. The communications with the sympathetic nerve are derived from the superior cervical ganglion. The Descendens noni is a long and slender twig, which quits the hypo- glossal just as that nerve is about to form its arch around the occipital artery, and descends upon the sheath of the carotid vessels. Just below the middle of the neck it forms a loop with a long branch (communicans noni) from the second and third cervical nerves. From the convexity of this loop branches are sent to the sterno-hyoideus, sterno-thyroideus, and both bellies of the omo-hyoideus ; sometimes also a twig is given off to the cardiac plexus, and occasionally one to the phrenic nerve. If the descendens noni be traced to its origin it will be found to be formed by a branch from the hypoglossal, and one from the first and second cervical nerves ; occasionally it receives also a filament from the pneumogastric. The'Thyro-hyoidean nerve is a small branch, distributed to the thyro hyoideus muscle. It is given off from the trunk of the hypoglossal near the posterior border of the hyoglossus muscle, and descends obliquely over the great cornu of the os Jiyoides. The Communicating filaments, with the gustatory nerve, are several small twigs, which ascend upon the hyoglossus muscle near its anterior border, and'form a kind of plexus with filaments sent down by the gusta- tory nerve. SPINAL NERVES. There are thirty-one pairs of spinal nerves, each arising by two roots, an anterior or motor root, and a posterior or sensitive root. The anterior roots proceed from a narrow white line, -interior lateral 35 410 CERVICAL NERVES. sulcus, on the antero-lateral column of the spinal cord, and gradually ap> proach towards the anterior longitudinal fissure as they descend. The posterior roots, more regular than the anterior, proceed from the posterior latera] sulcus, a narrow grey stria, formed by the in- ternal grey substance of the cord. They are larger, and the filaments of origin more nu- merous than those of the anterior roots. In the intervertebral foramina there is a ganglion on each of the posterior roots. The first cer- vical nerve forms an exception to these cha- racters ; its posterior root is smaller than the anterior; it often joins in whole or in part with the spinal accessory nerve and some- times with the hypoglossal: there is frequently no ganglion upon it, and when the ganglion J- exists it is often situated within the dura rnater, the latter being the usual position of the ganglia of the last two pairs of spinal nerves. After the formation of a ganglion, the two roots unite and constitute a spinal nerve, which escapes through the intervertebral foramen and divides into an anterior branch for the supply of the front aspect of the body, and a posterior branch for the posterior aspect. In the first cervical and two last sacral nerves this division takes place within the dura mater and in the upper four sacral nerves externally to that cavity, but within the sacral canal. The anterior branches, with the exception ofthe first two cervical nerves, are larger than the posterior; an arrangement which is propor- tioned to the larger extent of surface they are required to supply. The Spinal nerves are divided into— Cervical ..... 8 pairs. Dorsal-......12 Lumbar ..... 5 Sacral ...... 6 The cervical nerves pass off transversely from the spinal cord ; the dor- sal are oblique in their direction ; and the lumbar and sacral vertical; the latter form the large assemblage of nerves at the termination of the cord called cauda equina. CERVICAL NERVES. The cervical nerves increase in size from above downwards; the first (sub-occipital) passes out of the spinal canal between the occipital bone and the atlas ; and the last, between the last cervical and first dorsal ver- * Part of the cervical portion of the spinal cord, viewed on its posterior aspect; and showing its membranes and the posterior roots of the spinal nerves. 1, 1. The fissura longitudinalis posterior. 2, 2. The posterior roots of the cervical nerves; on the oppo- site side the corresponding roots are cut through near their origin. 3, 3. The membrana dentata. 4. The nervus accessorius, ascending between the posterior roots and the membrana dentata; on the opposite side this nerve has been removed. 5, 5. The dura mater or theca vertebralis. 6, 6. Openings in the dura mater for the passage of the roots of the nerves. 7, 7. The ganglia on the posterior roots of the spinal nerves. 8. The anterior roots of the spinal nerves. The posterior roots have been cut away in Order to show each anterior root, proceeding to join the nerve beyond the ganglion. CERVICAL PLEXUS. 411 tebra. Each nerve, at its escape from the intervertebral foramen, divides into an anterior and a posterior branch. The anterior branches of the four upper cervical nerves form the cervical plexus; the posterior branches, the posterior cervical plexus. The anterior branches of the four inferior cer- vical, together with the first dorsal, form the brachial plexus. Anterior Cervical Nerves.—The anterior branch of the first cervical nerve escapes from the vertebral canal through the groove upon the poste- rior arch of the atlas which supports the vertebral artery, beneath which it lies. It then descends in front ofthe transverse process ofthe atlas, sends several twigs to the rectus lateralis and recti antici, and forms an anasto- motic loop by communicating with an ascending branch of the second nerve. The anterior branch of the second cervical nerve at its exit from the in- tervertebral foramen between the atlas and the axis, gives twigs to the rectus anticus major, scalenus posticus and levator anguli scapulas mus- cles, and divides into three branches, viz. an ascending branch, which completes the arch of communication with the first nerve; and two de- scending branches, which communicate with the third nerve. The anterior branch of the third cervical nerve, double the size of the preceding, divides at its exit from the intervertebral foramen into numer- ous branches, some of which are distributed to the rectus major, longus colli, and scalenus posticus muscles, while others communicate and form loops and anastomoses with the second and fourth nerve. The anterior branch of the fourth cervical nerve, of the same size with the preceding, sends twigs to the rectus major, longus colli, and levator anguli scapulas, communicates by anastomosis with the third, and sends a small branch downwards to the fifth nerve. Its principal branches pass downwards and outwards across the posterior triangle of the neck, to- wards the clavicle and acromion. The anterior branches of the fifth, sixth, seventh, and eighth cervical nerves will be described with the brachial plexus, of which they form a part. cervical plexus. The cervical plexus is constituted by the loops of communication, and by the anastomoses which take place between the anterior branches of the four first cervical nerves. The plexus rests upon the levator anguli sca- pula?, posterior scalenus, and splenius muscle, and is covered in by the sterno-mastoid and platysma. The Branches ofthe cervical plexus may be arranged into three groups, superficial ascending, superficial descending; and deep- Superficial Deep C Superficialis colli, ' Ascending, < Auricularis magnus, ( Occipitalis minor. „ ,. ( Acromiales, Descending, j Claviculares< ' Communicating branches, Muscular, Communicans noni, Phrenic. 412 CERVICAL PLEXUS. The Superfidalis colli is formed by communicating branches from the s.. ond and third cervical nerves; it curves around the posterior border of the sterno-mastoid and crosses obliquely behind the external jugular veil to the anterior border of that muscle, where it divides into an ascend- ing und a descending branch; the descending branch is distributed to the integument on the side and front of the neck, as low down as the clavicle; the ascending branch passes upwards to the submaxillary region, and divides into four or five filaments, some of which pierce the platysma myoides and supply the integument as high up as the chin and lower part of the face, while others form a plexus with the descending branches of the facial nerve beneath the platysma. One or two filaments from this nerve accompany the external jugular vein. The Auricularis magnus, the largest of the three ascending branches of the cervical plexus, also proceeds from the second and third cervical nerve ; it curves around the posterior border of the sterno-mastoid, and ascends upon that muscle, lying parallel with the external jugular vein, to the parotid gland, where it divides into an anterior and a posterior branch. The anterior branch is distributed to the integument over the parotid gland, to the gland itself, communicating with the facial nerve, and to the external ear. The posterior branch pierces the parotid gland and crosses the mastoid process, where it divides into branches w7hich supply the pos- terior part of the pinna and the integument of the side of the head, and communicate with the posterior auricular branch of the facial and with the occipitalis minor. Previously to its division the auricularis magnus nerve sends off several facial branches which are distributed to the cheek. The Occipitalis minor arises from the second cervical nerve; it curves around the posterior border of the sterno-mastoid above the preceding, and ascends upon that muscle, parallel with its posterior border, to the lateral and posterior side of the head. It is distributed to the integument and to the muscles of this region, namely, to the occipito-frontalis, attollens and attrahens aurem, and communicates with the occipitalis major, auri- cularis magnus and posterior auricular branch of the facial. The Acromiales and Claviculares are two or three large nerves which proceed from the fourth cervical nerve, and divide into numerous branches which pass downwards over the clavicle, and are distributed to the inte- gument ofthe upper and anterior part ofthe chest from the sternum to the shoulder. The Communicating branches are filaments which arise from the loop between the first and second cervical nerve, and pass inwards to commu- nicate with the sympathetic, the pneumogastric, and the hypo-glossal nerve. The three first cervical nerves send branches to the first cervical ganglion ; the fourth sends a branch to the trunk of the sympathetic, or to the mi/dle cervical ganglion. From the second cervical nerve a large branch is ven off which goes to join the spinal accessory nerve. The J\j :ular branches proceed from the third and fourth cervical rerves; t are distributed to the trapezius, levator anguli scapulas, and ihomboid, .1. 'scles. The Co >municans noni is a long slender branch formed by filaments from the hist, second, and third cervical nerves; it descends upon .the outer side of the internal jugular vein, and forms a loop with the descen- dens noni over the sheath of the carotid vessels. POSTERIOR CERVICAL PLEXUS. 413 The Phrenic nerve (internal respiratory of Bell) is formed by filaments from the third, fourth, and fifth cervical nerves, receiving also a bran; h from the sympathetic. It descends to the root of the neck, resting upon the scalenus anticus muscle, then crosses the first portion ofthe subclavian artery, and enters the chest between it and the subclavian vein. \\„thin the chest it passes through the middle mediastinum, between the pleura and pericardium, and in front of the root of the lung to the diaphragm to which it is distributed, some of its filaments reaching the abdomen through the openings for the oesophagus and vena cava, and communicating with the phrenic and solar plexus, and on the right side with the hepatic plexus. The left phrenic nerve is rather longer than the right, from the inclination of the heart to the left side. Posterior Cervical Nerves.—The posterior division of the first cer- vical nerve (sub-occipital), larger than the anterior, escapes from the ver- tebral canal through the opening for the vertebral artery, lying posteriorly to that vessel, and emerges into the triangular space formed by the rectus posticus major, obliquus superior, and obliquus inferior. It is distributed to the recti and obliqui muscles, and sends one or two filaments down- wards to communicate with the second cervical nerve. The posterior branch of the second cervical nerve is three or four times greater than the anterior branch, and is larger than the other posterior cervical nerves. The posterior branch of the third cervical nerve is smaller than the preced- ing, but larger than the fourth ; and the other posterior cervical nerves go on progressively decreasing to the seventh. The posterior branches of the fourth, fifth, sixth, seventh and eighth nerves pass inwards between the muscles of the back in the cervical and upper part of the dorsal region, and reaching the surface near the middle line, are reflected outwards, to be distributed to the integument. The fourth and fifth are nearly trans- verse in their course, and lie between the semispinalis colli and complexus. The sixth, seventh, and eighth are directed nearly vertically downwards; they pierce the aponeurosis of origin of the splenius and trapezius. Posterior Cervical Plexus.—This plexus is constituted by the suc- cession of anastomosing loops and communications w7hich pass between the posterior branches of the first, second, and third cervical nerves. It is situated between the complexus and semispinalis colli, and its branches are the— Musculo-cutaneous, Occipitalis major. The Musculo-cutaneous branches pass inwards between the complexus and semispinalis colli to the ligamentum nuchas, distributing muscular filaments in their course. They then pierce the aponeurosis of the trape- zius and become subcutaneous, sending branches outwards {__, supply the integument of the posterior aspect of the neck, and upward? .> the poste- rior region of the scalp. . f .< . The Ocdpitalis major is the direct continuation of the „,* nd cervical nerve; it ascends obliquely inwards, between the obliquus,,inferior and complexus, pierces the complexus and trapezius after passing for a shori d^ance be'tween them, and ascends upon the posterior aspect ofthe head between the integument and occipito-frontalis, in company with the occi- 35 v 414 BRACHIAL PLEXUS. Fig. 186.« pital artery. The occipitalis major sends numerous branches to the mus- cles of the neck, and is distributed to the integument of the scalp, as far forwards as the middle of the vertex of the head. Its branches commu- nicate with those of the occipitalis minor. BRACHIAL PLEXUS. The Brachial or axillary plexus of nerves is formed by communications between the anterior branches of the four last cervical and first dorsal nerve. These nerves are all similar in size, and their mode of disposition in the formation of the plexus is the following: the fifth and sixth nerves unite to form a common trunk, which soon divides into two branches; the last cervical and first dorsal also unite immediately upon their exit from the intervertebral foramina, and the common trunk resulting from their union after a short course also di- vides into two branches; the seventh nerve passes outw7ards between the common trunks of the two preceding, and opposite the clavicle divides into a superior branch which unites with the inferior division of the supe- rior trunk, and an inferior branch which communicates with the superior division of the inferior trunk : from these divisions and communications the brachial plexus results. The brachial plexus communicates with the cervical plexus by means of a branch sent down from the fourth to the fifth nerve, and by the inferior branch of origin of the phrenic nerve, and also sends filaments of communication to the sympathetic. The plexus is broad in the neck, narrows as it descends into the axilla, and again en- larges at its lower part where it divides into its six terminal branches. Relations.—The brachial plexus is in relation in the neck with the two scaleni muscles, between which its nerves issue; lower down it is placed between the clavicle and subclavius muscle above, and the first rib and first serration of the serratus magnus muscle below. In the axilla, it is situated at first to the outer side and then behind the axillary artery, rest- ing by its outer border against the tendon of the subscapularis muscle. At this point it completely surrounds the artery by means of the two cords which are sent off to form the median nerve. Its Branches may be arranged into two groups, humeral and descend- ing— * A view ofthe brachial plexus of nerves and branches of arm. 1, 1. The scalenus anticus muscle, in front of which are the roots of the plexus. 2, 2. The median nerve 3. The ulnar nerve. 4. The branch to the biceps muscle. 5. The nerves of Wrisberg 6. The phrenic nerve from the 3d and 4th cervical. BRACHIAL PLEXUS. 415 Humeral Branches. Descending Branches. Superior muscular, External cutaneous, Short thoracic, Internal cutaneous, Long thoracic, Lesser internal cutaneous, Supra-scapular, Median, Subscapular, Ulnar, Inferior muscular. Musculo-spiral, Circumflex. The superior Muscular nerves are several large branches which are given off by the fifth cervical nerve above the clavicle; they are, a subclavian branch to the subclavius muscle, which usually sends a communicating filament to the phrenic nerve : a rhomboid branch to the rhomboidei mus- cles ; and frequently an angular branch to the levator anguli scapulas. The Short thoracic nerves (anterior) are two in number ; they arise from the brachial plexus at a point parallel with the clavicle, and are divisible into an anterior and a posterior branch. The anterior branch passes for- wards between the subclavius muscle and the subclavian vein, and is dis- tributed to the pectoralis major muscle, entering it by its costal surface. In its course it sends one or two twigs to the deltoid muscle and gives off a branch which forms a loop of communication with the posterior branch. The posterior branch passes forward beneath the axillary artery and unites with the communicating branch of the preceding to form a loop, from which numerous branches are given off to the pectoralis major and pecto- ralis minor. The Long thoracic nerve (posterior thoracic, external respiratory of Bell) is a long and remarkable branch arising from the fourth and fifth cervical nerves, immediately after their escape from the intervertebral foramina. It passes dow7n behind the plexus and axillary vessels, resting on the sca- lenus posticus muscle ; it then descends along the side of the chest upon the serratus magnus muscle to its lowest serration. It sends numerous filaments to this muscle in its course. The Supra-scapular nerve arises above the clavicle from the fifth cervical nerve and descends obliquely outwards to the supra-scapular notch; it then passes through the notch, crosses the supra-spinous fossa beneath the supra-spinatus muscle, and passing in front of the concave margin of the spine of the scapula enters the infra-spinous fossa. It is distributed to the supra-spinatus and infra-spinatus muscle. The Subscapular nerves are two in number; of which one arises from the brachial plexus above the clavicle, the other from the posterior aspect of the plexus within the axilla. They are distributed to the subscapularis muscle. , The Inferior muscular nerves are two or three branches which proceed from the lower and back part of the brachial plexus, and are distributed to the latissimus dorsi and teres major. The former of these is the longer, and follows the course ofthe subscapular artery. The terminal branches of the plexus are arranged in the following order: the external cutaneous, and one head of the median to the outer side of the artery • the other head of the median, internal cutaneous, lesser internal cutaneous,' and ulnar, upon its inner side; and the circumflex and mus- culo-spiral b£i»nd. 416 MEDIAN NERVE. The External Cutaneous Nerve (musculo-cutaneous, perforans Cas- serii) arises from the brachial plexus in common with the external head of the median; it pierces the coraco-brachialis muscle and passes between the biceps and brachialis anticus, to the outer side of the bend of the el- bow, where it perforates the fascia, and divides into an external and in- ternal branch. The branches pass behind the median cephalic vein, the external, the larger of the two, taking the course of the radial vein and communicating with the branches of the radial nerve on the back of the band; the internal and smaller following the direction of the supinator longus, communicating with the internal cutaneous, and at the lower third ofthe fore-arm sending off a twig, which accompanies the radial artery to the wrist, and distributes filaments to the synovial membranes of the joint. The external cutaneous nerve supplies the coraco-brachialis, biceps and brachialis anticus in the upper arm, and the integument of the outer side ofthe fore-arm as far as the wrist and hand. The Internal Cutaneous Nerve is one ofthe internal and smaller of the branches of the axillary plexus; it arises from the plexus in common with the ulnar and internal head ofthe median, and passes down the inner side of the arm in company with the basilic vein, giving off several cuta- neous filaments in its course. At about the middle of the upper arm it pierces the deep fascia by the side of the basilic vein and divides into two branches, anterior and posterior.. The anterior branch, the larger of the two, divides into several branches which pass in front of, and sometimes behind, the median basilic vein at the bend ofthe elbow, and descends in the course of the palmaris longus muscle to the wrist, distributing filaments to the integument in their course and communicating with the anterior branch of the external cutaneous on the outer side, and its own posterior branch on the inner side of the fore-arm. The posterior branch sends off several twigs to the integument over the inner condyle and olecranon, and then descends the fore-arm in the course of the ulnar vein as far as the wrist, supplying the integument on the inner side of the fore-arm and communicating with the anterior branch of the same nerve in front, and the dorsal branch of the ulnar nerve on the wrist. The Lesser Internal Cutaneous Nerve, or nerve of Wrisberg, the smallest of the branches of the brachial plexus, is very irregular in point of origin. It is a long and slender nerve, and usually arises from the common trunk of the last cervical and first dorsal nerve. Passing down- wards into the axillary space it communicates with the external branch of the first intercosto-humeral nerve, and" descends on the inner side of the internal cutaneous nerve, to the middle of the posterior aspect of the upper arm, where it pierces the fascia and is distributed to the integument of the elbow7, communicating with filaments of the posterior branch of the internal cutaneous and with the spiral cutaneous. In its course it gives off two or three cutaneous filaments to the integument of the inner and n anterior aspect of the upper arm. The Median Nerve has received its name from taking a course along the middle of the fore-arm to the palm of the hand ; it is, therefore, inter- mediate in position between the radial and ulnar nerves. It commences by two heads, which embrace the axillary artery; lies at first to the outer side of the brachial artery, which it crosses at its middle ; and descends MEDIAN NERVE. 417 Fig. 187 * on its inner side to the bend of the elbow. It then passes between the two heads of the pronator radii teres and flexor sublimis digitorum muscles, and runs down the fore-arm, between the flexor sublimis and profundus, and beneath the annular ligament, into the palm of the hand. The Branches of the median nerve are,— Muscular, Anterior interosseous, Superficial palmar, Digital. The Muscular branches are given off by the nerve at the bend of the elbow ; they are distri- buted to all the muscles on the anterior aspect of the fore-arm, with the exception of the flexor carpi ulnaris, and to the periosteum. The branch to the pronator radii teres sends off reflected branches to the elbow joint. The Anterior interosseous is a large branch ac- companying the anterior interosseous artery, and supplying the deep layer of muscles in the fore- arm. It passes beneath the pronator quadratus muscle, and pierces the interosseous membrane near the wrist. On reaching the posterior aspect of the wrist it joins a large and remarkable ganglion which gives off a number of branches for the supply of the joint. The Superficial palmar branch arises from the median nerve at about the lower fourth of the fore-arm : it crosses the annular ligament, and is distributed to the integument over the ball of the thumb and in the palm ofthe hand. The median nerve at its termination in the palm of the hand is spread out and flattened, and divides into six branches, one muscular and five digital. The muscular branch is distributed to the muscles of the ball of the thumb. The digital branches send twigs to the lumbricales muscles and are thus arranged : two pass outwards to the thumb to supply its borders; one to the radial side of the index finger; one subdivides for the supply of the adjoining sides of the index and middle fingers; and the remaining one, for the supply ofthe adjoining sides ofthe middle and rino; fingers. The digital nerves in their course along the fingers are situaied to the inner side of the digital arteries. Opposite the base of the first phalanx each nerve gives off a dorsal branch which runs along the border of the dorsum of the finger. Near the extremity of the finger the dioital nerve divides into a palmar and a dorsal branch ; the former sup- plvino- the sentient extremity of the finger, and the latter the structures around and beneath the nail. The digital nerve maintains no communica- tion with its fellow ofthe opposite side. • N>rves of front of fore-arm. 1. Median nerve. 2. Anterior branch of musculo- i dd nerve 3 Ulnar nerve. 4. Division of median nerve in the palm ITthe thumb 1st, *1, and radial side of 3d finger. 5. Division of ulnar nerve to ulnar side of 3d and both sides of 4th finger. 2b 418 ULNAR NERVE. The Ulnar Nerve is somewhat smaller than the median, behind which it lies, gradually diverging from it in its course. It arises from the bra- chial plexus in common with the internal head of the median and the in- ternal cutaneous nerve, and runs down the inner side of the arm, to the groove between the internal condyle and olecranon, resting upon the internal head of the triceps, and accompanied by the inferior profunda artery. At the elbow it is superficial, and supported by the inner con- dyle, against which it is easily compressed, giving rise to the thrilling sensation along the inner side of the fore-arm and little finger, ascribed to striking the " funny bone." It then passes between the two heads of the fiexqr carpi ulnaris and descends along the inner side of the fore-arm, crosses the annular ligament, and divides into two branches, superficial and deep palmar. At the commencement ofthe middle third ofthe fore- arm, it becomes applied against the artery, and lies to its ulnar side, as far as the hand. The Branches of the ulnar nerve are— Fig. 188.* Muscular in the upper arm, Articular, Muscular in the fore-arm, Anastomotic, Dorsal branch, Superficial palmar, Deep palmar. The Muscular branches in the upper arm are a few filaments distributed to the triceps. The Articular branches are several filaments to the elbow- joint, which are given off from the nerve as it lies in the groove between the inner condyle and the olecranon. The Muscular branches in the fore-arm are dis- tributed to the flexor carpi ulnaris and flexor pro- fundus digitorum muscle. The Anastomotic branch (n. cutaneus palmaris ulnaris) is a small nerve which arises from the ulnar at about the middle of the fore-arm, and divides into a deep and a superficial b^nch ; the former ac- companies the ulnar artery, the latter pierces the deep fascia, and is distributed to the integument, communicating with the posterior branch of the in- ternal cutaneous nerve. The Dorsal branch passes backwards beneath the tendon of the flexor carpi ulnaris, at the lower third of the fore-arm, and divides into branches, which supply the integument and two fingers and a half on the posterior aspect of the hand, communicating with the internal cutaneous and radial nerve. The Superficial palmar branch divides into three filaments, which are * A view of the nerves on the dorsal aspect of the fore-arm and hand. 1, 1. The ulnar nerve. 2, 2. The posterior interosseous nerve. 3. Termination of the nervus cutaneus humeri. 4. The dorsalis carpi, a branch ofthe radial nerve. 5, 5. A back view of the digital nerves. 6. Dorsal branch of the ulnar nerve. MUSCULO-SPIRAL NERVE. 419 distributed, one to the ulnar side of the little finger, one to the adjoining borders of the little and ring fingers, and a communicating branch to join the median nerve. The Deep palmar branch passes between the abductor and flexor minimi digiti, to the deep palmar arch, supplying the muscles of the little finger, and the interossei and other deep structures in the palm of the hand. The Musculo-spiral Nerve, the largest branch of the brachial plexus, arises from the posterior part of the plexus by a common trunk with the circumflex nerve. It passes downwards from its origin in front of the tendons of the latissimus dorsi and teres major muscle, and winds around the humerus in the spiral groove, accompanied by the superior profunda artery, to the space between the brachialis anticus and supinator longus, and thence onwards to the bend of the elbow, where it divides into two branches, the posterior interosseous and radial nerve. The Branches of the musculo-spiral nerve are— Muscular, Spiral cutaneous, Radial, Posterior interosseous. The Muscular branches are distributed to the triceps, to the supinator longus, and to the extensor carpi radialis longior. The Spiral cutaneous nerve pierces the deep fascia immediately below the insertion of the deltoid muscle, and passes down the outer side of the fore-arm as far as the wrist. It is distributed to the integument. The Radial nerve runs along the radial side of the fore-arm to the com- mencement of its lower third; it then passes beneath the tendon of the supinator longus, and at about two inches above the wrist joint pierces the deep fascia, and divides into an external and an internal branch. The external branch, the smaller of the two, is distributed to the outer border of the hand and thumb, and communicates with the posterior branch of the external cutaneous nerve. The internal branch crosses the direction of the extensor tendons of the thumb, and divides into several filaments for the supply of the ulnar border of the thumb, the radial border of the index finger, and the adjoining borders of the index and middle fingers. It communicates on the back of the hand with the dorsal branch of the ulnar nerve. In the upper third of the fore-arm the radial nerve lies beneath the border of the supinator longus muscle. In the middle third it is in rela- tion with the radial artery lying to its outer side. It then quits the artery and passes beneath the tendon of the supinator longus, to reach the back of the hand. ,. , The Posterior interosseous nerve, somewhat larger than the radial, sepa- rates from the latter at the bend of the elbow, pierces the supinator brevis muscle and emerges from its lower border on the posterior aspect of the fore-arm where it divides into branches which supply the whole of the muscles 'on the posterior aspect of the fore-arm. One branch, longer than the rest descends to the posterior part of the wrist, and forms a large o-ano-liform swelling (the common character of nerves which supply joints), from which numerous branches are distributed to the wrist joint 420 DORSAL NERVES. The Circumflex Nerve arises from the posterior part of the brachial plexus by a common trunk with the musculo-spiral nerve. It passes downwards over the border of the subscapularis muscle, winds around the neck of the humerus with the posterior circumflex artery, and ter- minates by dividing into numerous branches, which supply the deltoid muscle. The Branches of the circumflex nerve are muscular and cutaneous The Muscular branches are distributed to the subscapularis, teres minor, teres major, latissimus dorsi, and deltoid. The Cutaneous branches pierce the deltoid muscle, and are distributed to the integument of the shoulder. One of these cutaneous branches (cutaneus brachii superior), larger than the rest, winds around the posterior border of the deltoid, and divides into filaments which pass in a radiating direction across the shoulder, and are distributed to the integument. dorsal nerves. The dorsal nerves are twelve in number on each side ; the first appears between the first and second dorsal vertebra, and the last between the twelfth dorsal and first lumbar. They are smaller than the lower cervical nerves, and diminish gradually in size from the first to the tenth, and then increase to the twelfth. Each nerve, as soon as it has escaped from the intervertebral foramen, divides into two branches; a dorsal branch and the true intercostal nerve. The Dorsal branches pass directly backwards between the transverse processes of the vertebras, lying internally to the anterior costo-transverse ligament, where each nerve divides into an anterior or muscular and a posterior or musculo-cutaneous branch. The muscular branch enters the substance of the muscles in the direction of a line corresponding with the interval of separation between the longissimus dorsi and sacro-lumbalis, and is distributed to the muscles of the back, its terminal filaments reach- ing to the integument. The musculo-cutaneous branch passes inw7ards, crossing the semispinalis dorsi to the spinous processes of the dorsal verte- bras, giving off muscular branches in its course ; it then pierces the apo- neurosis of origin of the trapezius and latissimus dorsi, and divides into branches which are inclined outwards beneath the integument to which they are distributed. The dorsal branch of fhe^rstf dorsal nerve resembles in its mode of dis- tribution the dorsal branches of the last cervical. The dorsal branches of the last four dorsal nerves pass obliquely downwards and outwards into the substance of the erector spinae in the situation of the interspace between the sacro-lumbalis and longissimus dorsi. After supplying the erector spinas and communicating freely with each other they approach the surface along the outer border of the sacro-lumbalis, where they pierce the apo- neuroses of the transversalis, internal oblique, serratus posticus inferior, and latissimus dorsi, and divide into internal branches which supply the integument in the lumbar region upon the middle line, and external branches w7hich are distributed to the integument upon the side of the lumbar and in the gluteal region. Intercostal Nerves.—The Intercostal nerves receive one or two fila- ments from the adjoining ganglia ofthe sympathetic, and pass forwards in SECOND INTERCOSTO-HUMERAL NERVE. 421 the intercostal space with the intercostal vessels, lying below the veins and artery, and supplying the intercostal muscles in their course. At the termi- nation of the intercostal spaces near the sternum, the nerves pierce the in- tercostal and pectoral muscles, and incline downwards and outwards to be distributed to the integument of the mamma and front of the chest. Those which are situated between the false ribs pass behind the costal cartilages, and between the transversalis and obliquus internus muscles, and supply the rectus and the integument on the front ofthe abdomen. The first and last dorsal nerves are exceptions to this distribution. The anterior branch of the first dorsal nerve divides into tw7o branches; a smaller, which takes its course along the under surface of the first rib to the sternal extremity of the first intercostal space ; and a larger, which crosses obliquely the neck of the first rib to join the brachial plexus. The last dorsal nerve, next in size to the first, sends a branch of communication to the first lumbar nerve, to assist in forming the lumbar plexus. The Brandies of each intercostal nerve are, a muscular twig to the in- tercostal and neighbouring muscles, and a cutaneous branch which is given off at about the middle of the arch of the rib. The first intercostal nerve has no cutaneous branch. The cutaneous branches of the second and third intercostal nerves are named, from their origin and distribution, in- ter costo-humeral. The First Intercosto-humeral Nerve is of large size ; it pierces the external intercostal muscle of the second intercostal space, and divides into an internal and an external branch. The internal branch is distri- buted to the integument of the inner side of the arm. The external branch communicates with the nerve of Wrisberg, and divides into filaments which supply the integument upon the inner and posterior aspect of the arm as far as the elbow. This nerve sometimes takes the place of the nerve of Wrisberg. The Second Intercosto-humeral Nerve is much smaller than the preceding; it emerges from the external intercostal muscle of the third intercostal space between the serrations ofthe serratus magnus muscle, and divides into filaments w7hich are distributed to the integument of the shoulder. One of these filaments may be traced inwards to the integu- ment of the mamma. The two intercosto-humeral nerves not unfrequently communicate previously to their distribution. The cutaneous branches of the fourth and fifth intercostal nerve send anterior twigs to the integument ofthe mammary gland and posterior fila- ments to the scapular region of the back. The cutaneous branches of the remaining intercostal nerves reach the surface between the serrations of the serratus magnus muscle above and the external oblique below, and each nerve divides into an anterior and a posterior branch ; the former being distributed to the integument of the antero-lateral, and the latter to that of the lateral part of the trunk. The cutaneous branch of the last dorsal nerve is remarkable for its size (n. clunium superior anticus) ; it pierces the internal and external oblique muscles crosses the anterior part of the crest of the ilium, and is distri- buted to the integument ofthe gluteal region as low down as the trochanter major. 36 422 LUMBAR PLEXUS. LUMBAR NERVES. There are five pairs of lumbar nerves, of which the first makes its ap- pearance between the first and second lumbar vertebras, and the last be- tween the fifth lumbar and the base ofthe sacrum. The anterior branches increase in size from above downwrards. They communicate at their ori- gin with the lumbar ganglia of the sympathetic, and pass obliquely out- wards behind the psoas magnus or between its fasciculi, sending twigs to that muscle and to the quadratus lumborum. In this situation each nerve divides into two branches, a superior branch which ascends to form a loop of communication with the nerve above, and an inferior branch which descends to join in like manner the nerve below, the communications and anastomoses wilich are thus established constituting the lumbar plexus. The posterior branches diminish in size from above downwards; they pass backwards between the transverse processes of the corresponding vertebras, and each nerve divides into an internal and an external branch. The internal branch, the smaller of the two, passes inwards to be distri- buted to the multifidus spinas and interspinales, and becoming cutaneous supplies the integument of the lumbar region on the middle line. The external branches communicate with each other by several loops, and after supplying the deeper muscles, Fi£- 189-* pierce the sacro-lumbalis to reach the integument to which they are distributed. The external branches of the three lower lumbar nerves (nervi clunium superiores postici) descend over the superior part of the crest of the ilium, and are dis- tributed to the integument of the gluteal region. LUMBAR PLEXUS. The Lumbar plexus is formed by the communications and anas- tomoses which take place between the anterior branches of the five lumbar nerves, and between the latter and the last dorsal. It is narrow7 above and increases in breadth inferiorly, and is situated between the transverse processes of the lumbar vertebras and the quadratus lumborum behind, and the psoas magnus muscle in front. * A view of the lumbar and ischiatic plexus and the branches of the former. 14. The bodies of the lumbar vertebrae. 13. The psoas magnus muscle. 11. The iliacus internus muscle. 15. The quadratus lumborum muscle. 16. The diaphragm. 12. The three broad muscles of the abdomen. 17. The sartorius. 1. The lumbar plexus. 2. The ischiatic plexus. 3, 3. Abdomino-crural nerves. 4. External cutaneous nerve (inguino-cutaneous). 5, 6, 7. Cutaneous branches from (8) The anterior crural nerve. 9. The genito-crural nerve or spermaticus externus. 10, 10. The lower termination of the great sympathetic. EXTERNAL CUTANEOUS NERVE. 423 The Branches of the lumbar plexus are the— Musculo-cutaneous, Crural External-cutaneous, Obturator, Genito-crural, Lumbo-sacral. The Musculo-cutaneous Nerves, two in number, superior and infe- rior, proceed from the first lumbar nerve. The superior musculo-cutaneous nerve (lho-scrotal, dio-hypogastncus), passes outwards between the poste- rior fibres of the psoas magnus, and crossing obliquely the quadratus lumborum to the middle of the crest of the ilium, pierces the transversalis muscle, and gives off a cutaneous branch. It then winds along the crest of the ilium between the transversalis and internal oblique, and divides into two branches, abdominal and scrotal. The abdominal branch is con- tinued forwards parallel with the last intercostal nerve to near the rectus muscle, to which it sends branches and perforates the aponeuroses of the internal and external oblique to be distributed to the integument of the mons pubis and groin. The scrotal branch, opposite the anterior superior spinous process of the ilium, communicates with the inferior musculo- cutaneous nerve, and passes forw-ard to the external abdominal ring. It then pierces the cremaster muscle and accompanies the spermatic cord in the male, and the round ligament in the female, to be distributed to the integument of the scrotum or external labium. The inferior musculo-cuta- neous nerve (ilio-inguinal) also arises from the first lumbar nerve. It is much smaller than the preceding, crosses the quadratus lumborum below it, and curves along the crest of the ilium to the anterior superior spinous process, resting in its course upon the iliac fascia. It there pierces the transversalis fascia and muscle, communicates with the scrotal branch of the ilio-scrotal nerve, and passes along the spermatic canal with the sper- matic cord to be similarly distributed. The External Cutaneous Nerve (inguino-cutaneous) proceeds from the second lumbar nerve. It pierces the posterior fibres of the psoas muscle ; and crossing the iliacus obliquely, lying upon the iliac fascia, to the anterior superior spinous process of the ilium, passes into the thigh beneath Poupart's ligament. It then pierces the fascia lata at about two inches below the anterior superior spine ofthe ilium, and divides into two branches, anterior and posterior. The posterior branch crosses the tensor vaginas femoris muscle to the outer and posterior side of the thigh, and supplies the integument in that region. The anterior nerve divides into two branches which are distributed to the integument upon the outer bor- der of the thigh, and to the articulation of the knee. The Genito-crural proceeds also from the second lumbar nerve. It traverses the psoas magnus from behind forwards, and runs dow-n on the anterior surface of that muscle and beneath its fascia to near Poupart's ligament, where it divides into a genital and a crural branch. The genital branch (n. spermaticus seu pudendus externus) crosses the external iliac artery to the internal abdominal ring and descends along the spermatic canal, lying behind the cord to the scrotum, where it divides into branches which supply the spermatic cord and cremaster in the male, and the round ligament and external labium in the female. At the internal abdominal ring this nerve sends off a branch which after supplying the lower border 424 CRURAL NERVE. Fig. 190.* of the interna] oblique and transversalis, is distributed to the integument of the groin. The crural branch (lumbo-inguinalis), the most external of the two, descends along the outer border of the external iliac artery, and, crossing the origin of the circumflex ilii artery, enters the sheath of the femoral vessels in front ofthe femoral artery. It pierces the sheath below Poupart's ligament, and is distributed to the integument of the anterior aspect of the thigh as far as its middle. This nerve is often very small, and sometimes communicates with one of the cutaneous branches of the crural nerve. The Crural, or Femoral Nerve, is the largest of the divisions of the lumbar plexus ; it is formed by the union of branches from the second, third, and fourth lumbar nerves, and, emerging from beneath the psoas muscle, passes downwards in the groove between it and the iliacus, and beneath Poupart's ligament into the thigh, where it spreads out and divides into numerous branches. At Poupart's ligament it is separated from the femo- ral artery by the breadth of the psoas muscle, which at this point is scarcely more than half an inch in diameter, and by the iliac fascia, beneath which it lies. Branches.—While situated within the pelvis the crural nerve gives off several muscular branches to the iliacus, and one to the psoas. On emerg- ing from beneath Poupart's ligament the nerve becomes flattened and divides into numerous branches, which may be arranged into,— Cutaneous, Muscular, Branch to the femoral sheath, Short saphenous nerve, Long saphenous nerve. The Cutaneous nerves (middle cutaneous) twc in number, proceed from the anterior part of the crural, and after perforating the sartorius muscle to which they give filaments, pierce the fascia lata and are distributed to the integument of the mid- dle and lower part of the thigh and of the knee. The most external of these nerves perforates the upper part of the sartorius, communicates with the crural branch of the genito-crural, divides into two branches at about the middle of the thigh, and gives off numerous filaments to the anterior and outer aspect of the limb as far as the patella. The internal nerve perfo- rates the muscle at about its middle, pierces the fascia lata at the lower third of the thigh, descends to the inner condyle, and curves forward to the front of the knee, supplying the integument by many filaments. Be- sides these another cutaneous branch derived from the muscular branch * A view of the anterior crural nerve and branches. 1. Place of emergence of the nerve under Poupart's ligament. 2. Division of the nerve into branches. 3. Femoral artery. 4. Femoral vein. 5. Branches of obturator nerve. 6. Nervus saphenus SAPHENOUS NERVES. 425 to the vastus externus is found on the outer side of the lower third of the thigh. The Muscular branches are several large twigs which are distributed to the muscles of the anterior aspect of the thigh. One of these is sent to the rectus; one to the vastus externus, which gives off a cutaneous twig to the outer aspect of the thigh ; one to the crurasus, and one large and long branch to the vastus internus. From the two latter, filaments are distributed to the periosteum and knee joint. The sartorius receives its supply of nerves from the cutaneous nerves by which it is perforated. The Branch to the femoral sheath is a small nerve which passes inwards to the sheath of the femoral vessels at the upper part of the thigh, and di- vides into several filaments which surround the femoral and profunda ves- sels. Two of these filaments, one from the front, and the other from the posterior part of the sheath, unite to form a small nerve w-hich escapes from the saphenous opening and passes downwards with the saphenous vein. Other filaments are distributed to the adductor muscles, and com- municate with the long saphenous nerve. The Short saphenous nerve (n. cutaneus internus) inclines inwards to the sheath of the femoral vessels, and divides into a superficial and a deep branch. The superfidal branch passes downwards along the inner border of the sartorius muscle to the lower third of the thigh; it then pierces the fascia lata, joins the internal saphenous vein, and accompanies that vessel to the knee joint, where it terminates by communicating with the long saphenous nerve. The deep branch descends on the outer side of the sheath of the femoral vessels, and crosses the sheath at its lower part to a point opposite the termination of the femoral artery, where it divides into several filaments which constitute a plexus by their communication with other nerves. One of these filaments communicates with the descending branch of the obturator nerve, another with the long saphenous nerve, and two or three are distributed to the integument upon the internal and pos- terior aspect of the thigh. The Long saphenous nerve (n. cutaneus internus longus) inclines in- wards to the sheath of the femoral vessels, and entering the sheath accom- panies the femoral artery to the aponeurotic canal formed by the adductor longus and vastus internus muscles. It then quits the artery, and, pass- ing between the tendons of the sartorius and gracilis, descends along the inner side of the leg with the internal saphenous vein, crosses in front of the inner ankle, and is distributed to the integument on the inner side of the foot as far as the great toe. The internal saphenous nerve receives from the obturator nerve two branches of communication, one near its upper part, which passes through the angle of division of the femoral artery, and the other at the internal condvle The branches which it gives off in its course are, a femoral cutaneous branch, at about the middle of the thigh, distributed to the in- tegument of the inner and posterior aspect of the limb, and communicat- ing with other cutaneous filaments from the saphenous below the knee ; a tibial cutaneous branch proceeding from the nerve a little above the internal condvle passing between the sartorius and gracilis and descending the inner aspect of the leg to the ankle ; an articular branch of small size, pro- ceeding from the nerve while in the aponeurotic canal of the femoral aiterv °and passing directlv to the knee joint to supply the synovial mem- brane'- 'an anterior cutaneous branch proceeding from the saphenous at the ' 36* 426 SACRAL NERVES. inner condyle, perforating the sartorius, and dividing into a number of filaments which supply the integument over the patella and around the joint, and the integument ofthe front and outer aspect ofthe leg as far as the ankle ; lastly, cutaneous filaments below the knee to supply the inner side and front of the leg and foot, and articular branches to the ankle joint. The Obturator Nerve is formed by a branch from the third, and an- other from the fourth lumbar nerve. It passes downwards among the fibres ofthe psoas muscle, through the angle of bifurcation ofthe common iliac vessels, and along the inner border of the brim of the pelvis, to the obturator foramen, where it joins the obturator artery. Having escaped from the pelvis it gives off two small twigs to the obturator externus muscle and divides into four branches, three anterior, which pass in front of the adductor brevis, supplying that muscle, the pectineus, the adductor longus, and the gracilis ; and a posterior branch which passes downwards behind the adductor brevis, and ramifies in the adductor magnus. From the branch which supplies the adductor brevis, a communicating filament passes outwards through the angle of bifurcation of the femoral vessels to unite with the long saphenous nerve. From the branch to the adductor longus a long cutaneous nerve proceeds, which issues from be- neath the inferior border of that muscle, sends filaments of communication to the plexus ofthe short saphenous nerve, and descends to the inner side of the knee, where it pierces the fascia and communicates with the long saphenous nerve. It is distributed to the integument upon the inner side of the leg; From the posterior branch an articular branch is given off which pierces the adductor magnus muscle, accompanies the popliteal artery, and is distributed to the synovial membrane of the knee joint on its posterior aspeet. The Lumbo-sacral Nerve.—The anterior division of the fifth lumbar nerve, conjoined with a branch from the fourth, constitutes the lumbo- sacral nerve, which descends over the base of the sacrum into the pelvis, and assists in forming the sacral plexus. SACRAL NERVES. There are six pairs of sacral nerves; the first escape from the vertebral canal through the first sacral foramina, and the two last betw-een the sacrum and coccyx. The posterior sacral nerves are very small, and diminish in size from above downwards; they communicate with each other immedi- ately after their escape from the posterior sacral foramina, and divide into external and internal branches. The external branches pierce the gluteus maximus, to which they give filaments, and are distributed to the integu- ment of the posterior part of the gluteal region (n. cutanei clunium poste- riores). The internal supply the integument over the sacrum and coccyx. The anterior sacral nerves diminish in size from above downwards ; the first is large and unites with the lumbo-sacral nerve; the second, of equal size, unites with the preceding; the third, which is scarcely one-fourth so large as the second, also joins with the preceding nerves in the formation of the sacral plexus. The fourth anterior sacral nerve is about one-third the size of the preceding sacral nerve ; it divides into several branches, one of which is sent to the sacral plexus, a second to join the fifth sacral SACRAL PLEXUS. 427 Fig. 191.* nerve, a third to the viscera of the pelvis commu- nicating with the hypogastric plexus, and a fourth to the coccygeus muscle, and to the integument around the anus. The fifth anterior sacral nerve presents about half the size of the fourth; it di- vides into two branches, one of which communi- cates with the fourth, the other with the sixth. The sixth sacral nerve (coccygeal) is exceedingly small; it gives off an ascending filament which is continuous with the communicating branch of the fifth; and a descending filament which passes downwards by the side of the coccyx and traverses the fibres of the great sacro-ischiatic ligament to be distributed to the gluteus maximus and to the integument. All the anterior sacral nerves receive branches from the sacral ganglia of the sympathetic at their emergence from the sacral foramina. SACRAL PLEXUS. The Sacral plexus is formed by the lumbo-sacral and by the anterior branches of the four upper sacral nerves. The plexus is triangular in form, the base corresponding with the whole length ofthe sacrum, and the apex with the lower part of the great ischiatic foramen. It is in relation behind with the pyriformis muscle, and in front with the pelvic fascia, which latter separates it from the branches of the internal iliac artery, and from the viscera of the pelvis. The Branches of the sacral plexus are divisible into the internal and the external; they may be thus arranged :— Internal. External. Visceral, Muscular, Muscular. Gluteal, - Internal pudic, —• Lesser ischiatic, - Greater ischiatic. — The Visceral nerves are three or four large branches which are derived from the fourth and fifth sacral nerves: they ascend upon the side of the rectum and bladder; in the female upon the side of the rectum, the va- gina and the bladder; and interlace with the branches of the hypogastric plexus, sending in their course numerous filaments to those viscera. The Muscular branches given off within the pelvis are one or two twigs to the levator ani; an obturator branch; which curves around the spine of the ischium to reach the internal surface of the obturator internus mus- cle ; a coccygeal branch; and an hasmorrhoidal nerve which passes throuo-h the two ischiatic openings and descends to the termination of the rectum to supply the sphincter and the integument. • A view ofthe branches ofthe ischiatic plexus to the hip and back ofthe thigh. 1, 1. Posterior sacral nerves. 2. Nervi glutei. 3. The internal pudic nerve (nervus puden- dalis longus superior). 4. The lesser ischiatic nerve, giving off the perineal cutaneous (pudendalis longus inferior), and 5. The ramus femoralis cutaneus posterior. The re- ference to the great ischiatic has been omitted. It is seen to the right of 3. 428 LESSER ISCHIATIC NERVE. The Muscular branches supplied by the sacral plexus externally to the pelvis are, a branch to the pyramidalis; a branch to the gemellus supe- rior ; and a branch of moderate size which descends between the gemelli muscles and the ischium, and is distributed to the gemellus inferior, the quadratus femoris, and the capsule of the hip joint. The Gluteal Nerve (superior gluteal) is a branch of the lumbo-sacral; it passes out of the pelvis with the gluteal artery, through the great sacro- ischiatic foramen, and divides into a superior and an inferior branch. The superior branch follows the direction of the superior curved line of the ilium, accompanying the deep superior branch of the gluteal artery, and sending filaments to the gluteus medius and minimus. The inferior passes obliquely downwards and forwards between the gluteus medius and minimus, distributing numerous filaments to both, and terminates in the tensor vaginas femoris muscle. The Internal Pudic Nerve arises from the lower part of the sacral plexus, passes out of the pelvis through the great sacro-ischiatic foramen below7 the pyriformis muscle, and takes the course of the internal pudic artery. While situated beneath the obturator fascia it lies below that vessel and divides into a superior and an inferior branch. The Superior nerve (dorsalis penis) ascends upon the posterior surface of the ramus of the ischium, pierces the deep perineal fascia and accom- panies the arteria dorsalis penis to the glans, to w7hich it is distributed. At the root of the penis this nerve gives off a cutaneous branch which runs along the side ofthe organ, gives filaments to the corpus cavernosum, and with its fellow of the opposite side supplies the integument of the upper two-thirds of the penis and prepuce. The Inferior or perineal nerve pursues the course of the internal pudic artery in the perineum and sends off three principal branches, an external perineal branch, which ascends upon the outer side ofthe crus penis, and supplies the scrotum; a superficial perineal branch, which accompanies the artery of that name and distributes filaments to the scrotum, to the integument of the under part of the penis and to the prepuce ; and, thirdly, the bulbo-urethral branch, which sends twigs to the sphincter ani, trans- versus perinei, and accelerator urinas, and terminates by ramifying in the corpus spongiosum. In the female the internal pudic nerve is distributed to the parts analo- gous to those of the male. The superior branch supplies the clitoris ; and the inferior the vulva and parts in the perineum. The Lesser Ischiatic Nerve passes out of the pelvis through the great sacro-ischiatic foramen below the pyriformis muscle, and divides into muscular and cutaneous branches. The muscular branches, inferior glu- teal, are distributed to the gluteus maximus; some ascending in the sub- stance of that muscle to its upper border, and others descending. The cutaneous branches are, several ascending filaments to the integument over the gluteus maximus (n. cutanei clunium inferiores), perineal cuta- neous, and middle posterior cutaneous. The Perineal cutaneous nerve (pudendalis longus inferior), curves around the tuberosity of the ischium and ascends in a direction parallel to the ramus of the ischium and os pubis to the scrotum, where it communicates POPLITEAL NERVE. 429 with the superficial perineal nerve, and divides into an internal and an external branch. The internal branch passes down upon the inner side ofthe testis to the scrotum; the external branch to its outer side, and both terminate in the integument of the under border of the penis. The Middle posterior cutaneous nerve crosses the tuberosity of the is- chium and pierces the deep fascia at the lower border ofthe gluteus max- imus. It then passes downw7ards along the middle of the posterior aspect of the thigh and of the popliteal region, and is distributed to the integu- ment as far as the middle of the calf of the leg. In its course the nerve gives off several cutaneous branches to the integument of the inner and outer side of the thigh, and in the popliteal region a communicating branch which pierces the fascia of the leg and unites with the external saphenous nerve. The Great Ischiatic Nerve is the largest nervous cord in the body; it is formed by the sacral plexus, or rather is a prolongation of the plexus, and at its exit from the great sacro-ischiatic foramen beneath the pyriformis muscle measures three quarters of an inch in breadth. It descends through the middle of the space between the trochanter major and tuberosity of the ischium, and along the posterior part ofthe thigh to about its lower third, where it divides into two large terminal branches, popliteal and peroneal. This division sometimes takes place at the plexus, and the two nerves descend together side by side; occasionally they are separated at their commencement by a part or the whole of the pyriformis muscle. The nerve in its course down the thigh rests upon the gemellus superior, ten- don of the obturator internus, gemellus inferior, quadratus femoris, and adductor magnus muscle, and is covered in by the gluteus maximus, biceps, semi-tendinosus, and semi-membranosus. The Branches of the great ischiatic nerve, previously to its division, are muscular and articular. The muscular branches are given off from the upper part of the nerve, and supply both heads of the biceps, the semi- tendinosus, semi-membranosus, and adductor magnus. The articular branch descends to the upper part of the external condyle of the femur, and divides into filaments which are distributed to the fibrous capsule and to the synovial membrane of the knee joint. The Popliteal Nerve passes through the middle ofthe popliteal space, from the division of the great ischiatic nerve to the low7er border of the popliteus muscle, accompanies the artery beneath the arch of the soleus, and becomes the posterior tibial nerve. It is superficial in the whole of its course, and lies externally to the vein and artery. The Branches of the popliteal nerve are muscular or sural, and articular, and a cutaneous branch, the communicans pophtei. The Muscular branches, of considerable size, and four or five in num- ber are distributed to the two heads of the gastrocnemius, to the soleus, plantaris, and popliteus. _ ., The Articular nerve pierces the ligamentum posticum Winslowii, and supplies the interior of the knee joint. It usually sends a twig to the popliteus muscle. . . . The Communicans poplitei (communicans tibialis) is a large nerve which arises from the popliteal at about the middle of its course, and de- scends between the two heads ofthe gastrocnemius, and along the groove 430 POSTERIOR TIBIAL NERVE. formed by the two bellies of that muscle; at a variable distance below the articulation of the knee it receives a large branch, the communicans peronei, from the peroneal nerve, and the two together constitute the ex- ternal saphenous nerve. The External saphenous nerve pierces the deep fascia below the fleshy part of the gastrocnemius muscle, and continues its course down the leg, lying along the outer border of the tendo Achillis and by the side of the external saphenous vein, which it accompanies to the foot. At the lower part of the leg it winds around the outer malleolus, and is distributed to the outer side of the foot and little toe, communicating with the external peroneal cutaneous nerve, and sending numerous filaments to the integu- ment of the heel and sole of the foot Fig. 192* Fig. 193.J The Posterior Tibial Nerve is continued along the posterior aspect of the leg from the lower border of the popliteus muscle to the posterior part of the inner ankle, where it divides into the internal and external plantar nerve. In the upper part of its course it lies to the outer side of * A view of some of the branches of the popliteal nerve. 1. The popliteal nerve. ' ,'terminations of the ramus femoralis cutaneus posterior. 4, 5. The saphenous nerve, b, b. Ihe external saphenous or communicans tibiae. t A view of the posterior tibial nerve in the back of the leg. 1 and 2, indicate ita course, the upper part of the peroneal nerve being seen to the right. PERONEAL NERVE. 431 the posterior tibial artery; it then becomes placed superficially to that vessel, and at the ankle is again situated to its outer side ; in the lower third of the leg it lies parallel with the inner border of the tendo Achillis. The Branches of the posterior tibial nerve are three or four muscular twigs to the deep muscles of the posterior aspect of the leg, the branch to the flexor longus pollicis accompanies the fibular artery ; one or two fila- ments which entwine around the artery and then terminate in the integu- ment;* and two or three plantar cutaneous branches which pass down- wards upon the inner side of the os calcis, and are distributed to the integument of the heel. The Internal Plantar Nerve, larger than the external, crosses the posterior tibial vessels to enter the sole of the foot, where it lies in the interspace between the abductor pollicis and flexor brevis digitorum; it then enters the sheath of the Fis- 194-t latter muscle, and divides opposite the bases of the metatarsal bones into three digital branches ; one to supply the adjoining sides of the great and second toe; the second the adjoining sides of the second and third toe ; and the third the corresponding sides of the third and fourth toes. This distribution is precisely similar to that of the digital branches of the median nerve. In its course the internal plantar nerve gives off cutaneous branches to the integument of the inner side and sole of the foot; muscular branches to the muscles forming the inner and middle group ofthe sole; a digital branch to the inner border of the great toe ; and articular branches to the articula- tions of the tarsal and metatarsal bones. The External Plantar Nerve, the smaller of the two, foliows the course of the external plantar artery to the outer border of the musculus accesso- rius, beneath which it sends several large muscular branches to supply the adductor pollicis and the articulations of the tarsal and metatarsal bones. It then gives branches to the integument of the outer border and sole of the foot, and sends forward two digital branches to supply the little toe and one half the next. The Peroneal Nerve is one-half smaller than the popliteal; it passes downwards by the side of the tendon of the biceps, crossing the inner head of the o-astrocnemius and the origin of the soleus, to the neck of the * It is extremely interesting, in a physiological point of view, to observe the mode of distribution of these filaments. I have traced them in relation with several, and I have no doubt that they exist in connexion with all the superficial arteries. They seem to be the direct monitors to the artery of the presence or approach of danger. t A view of the termination of the posterior tibial nerve in the sole of the foot. 1. In- side of the foot. 2. Outer side. 3. Heel. 4. Internal plantar nerve. 5. External plantar nerve 6 Branch to flexor brevis. 7. Branch to outside of little toe. 8. Branch to space between 4th and 5th toes. 9, 9, 9. Digital branches to remaining spaces. 10. Branch to internal side of great toe. 432 MUSCULO-CUTANEOUS NERVE. fibula, where it pierces the origin of the peroneus longus muscle, and divides into two branches, the anterior tibial and musculo-cutaneous. The Branches of the peroneal nerve previously to its division are, the communicans peronei, cutaneous, articular, and muscular. The commu- nicans peronei, much smaller than the communicans poplitei, crosses the external head of the gastrocnemius to the middle of the leg. It there sends a large branch to join the communicans poplitei and constitute the external saphenous nerve, and descends very much reduced in size with the external saphenous vein to the side of the external ankle, to which and to the integument of the heel it distributes filaments. The cutaneous branch passes down the outer side of the leg, supplying the integument. The articular is a small branch distributed to the knee joint. The muscular branches are twigs to the short head of the biceps, peroneus longus, and tibialis anticus. The Anterior Tibial Nerve commences at the Fig. 195* bifurcation ofthe peroneal, upon the head of the fibula, and passes beneath the upper part ofthe extensor longus digitorum, to reach the outer side of the anterior tibial artery, just as that vessel has emerged through the open- ing in the interosseous membrane. It descends the an- terior aspect of the leg with the artery; lying at first to its outer side, and then in front of it, and near the ankle becomes again placed to its outer side. Reaching the ankle, it passes beneath the annular ligament; accom- panies the dorsalis pedis artery, supplies the adjoining sides of the great and second toes, and communicates with the internal peroneal cutaneous nerve. The Branches given off by the anterior tibial nerve are, muscular to the muscles in its course, and on the foot a tarsal branch which passes beneath the extensor brevis digitorum, and distributes filaments to the inter- ossei muscles and to the articulations of the tarsus and metatarsus. The Musculo-cutaneous Nerve passes downwards in the direction of the fibula, in the substance of the peroneus longus ; it then passes forwards to get between the peroneus longus and brevis, and at the lower third of the leg pierces the deep fascia, and divides into two peroneal cutaneous branches. In its course it gives off several branches to the peronei muscles. The Peroneal cutaneous nerves pass in front of the ankle joint, and are distributed to the integument of the foot and toes; the external supplying three toes and a half, and the internal one and a half. They communicate with the saphenous and anterior tibial nerves. The external saphenous nerve frequently supplies the fifth toe and the adjoining side of the fourth. * A view of the anterior tibial nerve. 1. The peroneal nerve. 2, 3. The anterior tibial nerve accompanying the artery of the same name. CRANIAL GANGLIA. 433 SYMPATHETIC NERVES. The Sympathetic system consists of a series of ganglia, extending along each side of the vertebral column from the head to the coccyx, communi- cating with all the other nerves of the body, and distributing branches to all the internal organs and viscera. It communicates with the other nerves immediately at their exit from the cranium and vertebral canal. The fourth and sixth nerves, however, form an exception to this rule ; for with these it unites in the cavernous sinus; and with the olfactory, optic, and auditory, at their ultimate ex- pansions. The branches of distribution accompany the arteries which supply the different organs, and form communications around them, which are called plexuses, and take the name of the artery with which they are associated : thus we have the mesenteric plexus, hepatic plexus, splenic plexus, &e. All the internal organs of the head, neck, and trunk are supplied with branches from the sympathetic, and some of them exclusively ; hence it is considered a nerve of organic life. It is called the ganglionic nerve from the circumstance of being formed by a number of ganglia; and from the constant disposition which it evinces in its distribution, to communicate and form small knots or ganglia. There are five sympathetic ganglia in the head; viz. the ganglion ot Ribes; the ciliary or lenticular; the spheno-palatine, or Meckel's; the otic, or Arnold's; and the submaxillary: three in the neck; superior, middle, and inferior: twelve in the dorsal region; four in the lumbar re- gion ; and four or five in the sacral region. Each ganglion may be considered as a distinct centre giving off branches in four different directions, viz., superior or ascending, to communicate with the ganglion above; inferior or descending, to communicate with the ganglion below ; external, to communicate with the spinal nerves ; and internal, to communicate with the sympathetic filaments of the opposite side, and to be distributed to the viscera. CRANIAL GANGLIA. Ganglion of Ribes, Ciliary, or lenticular ganglion, Spheno-palatine, or Meckel's ganglion, Otic, or Arnold's ganglion, Submaxillary ganglion. The Ganglion of Ribes is a small ganglion situated upon the anterior communicating artery, and formed by the union of the sympathetic fila- ments which accompany the ramifications of the two anterior cerebral arteries These filaments are derived from the carotid plexus at each side • and through their intervention, the ganglion of Ribes is brought into connexion with the carotid plexus, and with the other ganglia of the sym- pathetic. This ganglion, though of very small size is interesting as being the superior point of union between the sympathetic chains of opposite ^The Ciliary Ganglion (lenticular) is a small quadrangular and flattened 37 2c 434 CILIARY GANGLION. ganglion situated within the orbit, between the optic nerve and the exter- nal rectus muscle; it is in close contact with the optic nerve, and is sur- rounded by adipose tissue, which renders its dissection somewhat difficult. Its branches of distribution are the ciliary, which arise from its anterior angles by two groups: the upper group, consisting of about four filaments; and the lower, of five or six. They accompany the ciliary arteries in a Fig. 196« waving course, and divide into a number of filaments which pierce the sclerotic around the optic nerve, and supply the tunics of the eyeball. A small filament is said by Tiedemann, to accompany the arteria centralis retina? into the centre of the globe of the eye. Its branches of communication are three, one, the long root, which pro- ceeds from the posterior superior angle to the nasal branch of the ophthal- mic nerve ; a short thick branch, the short root, from the posterior inferior angle to the inferior division of the third nerve; and a slender filament, the sympathetic root, which passes backwards to the cavernous sinus, and communicates with the carotid plexus. Occasionally the ciliary ganglion * The cranial ganglia ofthe sympathetic nerve. 1. The ganglion of Ribes. 2. The filament by which it communicates with the carotid plexus (3). 4. The ciliary or len- ticular ganglion, giving off ciliary branches for the supply of the globe of the eye. 5. Part of the inferior division of the third nerve, receiving a short thick branch (the short root) from the ganglion. 6. Part ofthe nasal nerve, receiving a longer branch (the long root) from the ganglion. 7. A slender filament (the sympathetic root) sent directly backwards from the ganglion to the carotid plexus. 8. Part of the sixth nerve in the cavernous sinus, receiving two branches from the carotid plexus. 9. Meckel's ganglion (spheno-palatine). 10. Its ascending branches, communicating with the superior maxil- lary nerve. 11. Its descending or palatine branches. 12 Its internal branches, spheno- palatine or nasal. 13. The naso-palatine branch, one of the nasal branches. * The naso-palatine ganglion. 14. The posterior branch of the ganglion, the Vidian nerve. 15. Its carotid branch (n. petrosus profundus) communicating with the carotid plexus. 16. Its petrosal branch (n. petrosus superficialis minor), joining the intumescentia gangli- formis of the facial nerve. 17. The facial nerve. 18. The chorda tympani nerve, which descends to join the gustatory nerve. 19. The gustatory nerve. 20. The submaxillary ganglion, receiving the chorda tympani, and other filaments from the gustatory. 21. The superior cervical ganglion of the sympathetic. SPHENO-PALATINE GANGLION. 435 receives also a filament of communication (middle root) from the spheno- palatine ganglion; and it sometimes sends a twig to the abducens nerve. The Spheno-palatine Ganglion (Meckel's) the largest of the cranial ganglia of the sympathetic, is very variable in its dimensions. It is situated in the spheno-maxillary fossa. Its branches are divisible into four groups; ascending, descending, in- ternal, and posterior. The branches of distribution are the internal and the descending. The internal branches are the nasal and the naso-palatine. The nasal or spheno-palatine nerves, four or five in number, enter the nasal fossa through the spheno-palatine foramen, and are distributed to the mucous membrane of the superior meatus, and superior and middle spongy bones. Besides these, several branches issue through small openings in the palate and sphenoid bone, and supply the mucous membrane of the upper part of the pharynx and the Eustachian tube. The naso-palatine nerve (Scarpa) enters the nasal fossa with the nasal nerves, and crosses the roof of the nares to reach the septum, to which it gives several filaments. It then curves downwards and forwards to the naso-palatine canal, and enters the anterior palatine canal, where it joins with its fellow of the opposite side, and receives filaments from the ante- rior dental and palatine nerves. By this junction an enlargement is formed, the naso-palatine ganglion (Cloquet's), which distributes filaments to the mucous membrane of the palate, immediately behind the incisor teeth. The descending branches are the three palatine nerves, anterior, middle, and posterior. The anterior palatine nerve, the largest of the three, descends from the ganglion through the posterior palatine canal, and emerges at the posterior palatine foramen. It then passes forwards in the substance of the hard palate to which it is distributed, and communicates with the naso-palatine ganglion and with its branches. While in the posterior palatine canal this nerve gives off several branches, which enter the nose through openings in the palate bone, and are distributed to the middle and inferior meatus, the inferior spongy bone, and the antrum. The middle palatine nerve descends through the same canal to the pos- terior palatine foramen, and distributes branches to the tonsil, soft palate, and uvula. The posterior palatine nerve, the smallest of the three, quits the other nerves to enter a distinct canal, from which it emerges by a separate open- ing behind the posterior palatine foramen. It is distributed to the hard palate and gums near the point of its emergence, and to the tonsil and soft palate. , The branches of communication are the ascending and the posterior. The ascending branches are, one o, two to join the superior maxillary nerve- one to the abducens nerve; one to the ciliary ganglion constituting its middle root • and occasionally two filaments to the optic nerve within the orbit The posterior branch is the Vidian or pterygoid nerve. The Vidian* nerve passes directly backwards from the spheno-palatine • Guido Guidi, latinized into Vidus Vidius, was professor of anatomy and medicine in the College of France in 1542. His work is posthumous, and was pabhshed in 1611 436 OTIC GANGLION. ganglion, through the pterygoid or Vidian canal, to the foramen lacerum basio cranii, where it divides into two branches, the carotid and petrosal. The carotid branch (n. petrosus profundus) crosses the foramen lacerum, surrounded by the ligamentous substance which closes that opening and ent :lB the carotid canal by several filaments to join the carotid plexus. The petrosal branch (n. petrosus superficialis major) enters the cranium through the foramen lacerum basis cranii, piercing the ligamentous sub- stance of the latter, and passes backwards beneath the Casserian ganglion and dura mater, embedded in a groove upon the anterior surface of the petrous bone, to the hiatus Fallopii. In the hiatus Fallopii the petrosal branch of the Vidian receives a twig from Jacobson's nerve, and termi- nates in the intumescentia gangliformis of the facial nerve. While in the pterygoid canal the Vidian nerve sends off a minute branch which passes through an opening in the sphenoid bone and joins the otic ganglion. The Otic Ganglion (Arnold's)* is a small oval-shaped and flattened ganglion, resting against the inner surface of the inferior maxillary nerve, immediately below the foramen ovale ; it is in relation externally with the trunk of the inferior maxillary nerve, just at the point of union of the motor root; internally it rests against the cartilage of the Eustachian tube and tensor palati muscle ; and posteriorly it is in contact with the arteria me- ningea media. It is closely adherent to the internal pterygoid nerve, and appears like a swelling upon that branch. The branches of the otic ganglion are seven in number; two of distri- bution, and five of communication. The branches of distribution are, a small filament to the tensor tympani muscle, and one to the tensor palati muscle ; the latter is usually derived from the internal pterygoid nerve, at the point where that nerve is enclosed by the ganglion. The branches of communication are, two or three filaments to the outer portion of the inferior maxillary nerve; one or two filaments to the auri- cular nerve; a filament to the chorda tympani; filaments to the arteria meningea media to communicate with the nervi molles ; a filament which enters the cranium through the foramen spinosum with the arteria me- ningea media, and accompanies the nervus petrosus superficialis minor to the hiatus Falopii, where it joins the intumescentia gangliformis of the facial nerve; a filament which enters the cranium through a small canal behind the foramen rotundum to join the Casserian ganglion ; a filament which enters a small canal near the foramen ovale to communicate with the Vidian nerve ; and the nervus petrosus superficialis minor. The latter nerve ascends from the ganglion to a small canal situated between the foramen ovale and foramen spinosum, and passes backwards on the petrous bone to the hiatus Falopii, where it divides into two filaments. One of these filaments enters the hiatus and joins the intumescentia gan- gliformis of the facial; the other passes to a minute foramen nearer the base ofthe petrous bone and enters the tympanum, where it communicates with a branch of Jacobson's nerve. The Submaxillary Ganglion is a small round or triangular ganglion, •Frederick Arnold, "Dissertatio Inauguralis de Parte Cephalica Nervi Sympathetici," Heidelberg, 182C; and " Ueber den Ohrknoten," 1828. cervical ganglia. 437 situated upon the submaxillary gland, in close relation with the gustatory nerve and near the posterior border of the mylo-hyoideus muscle. Its branches of distribution, six or eight in number, divide into many filaments, which supply the substance of the submaxillary gland and Wharton's duct. , Its branches of communication are, two or three from and to the gusta- tory nerve ; one from the chorda tympani; and one or two filaments which pass to the facial artery and communicate with the nervi molles from the cervical portion of the sympathetic. Carotid Plexus.—The ascending branch of the superior cervical gan- glion enters the carotid canal with the internal carotid artery, and divides into two branches, which form several loops of communication with each other around the artery. These branches, together with those derived from the petrosal branch of the Vidian, constitute the carotid plexus. They also form frequently a small gangliform swelling upon the under part of the artery, which is called the carotid ganglion. The latter, however, is not constant. The continuation of the carotid plexus onwards with the artery by the side of the sella turcica, is called the cavernous plexus. The carotid plexus is the centre of communication between all the cra- nial ganglia; and being derived from the superior cervical ganglion, be- tween the cranial ganglia and those of the trunk, it also communicates with the greater part of the cerebral nerves, and distributes filaments with each of the branches of the internal carotid, which accompany those branches in all their ramifications. Thus, the Ganglion of Ribes is formed by the union of the filaments which accompany the anterior cerebral arteries, and which meet on the anterior communicating artery. The ciliary ganglion communicates with the plexus by means of the long branch w7hich is sent back to join it in the cavernous sinus. The spheno-palatine, and with it the naso-palatine ganglion, joins the plexus by means of the carotid branch of the Vidian. The submaxillary ganglion is brought into connexion with it by means of the otic ganglion, and the otic ganglion by means of the tympanic nerve and the Vidian. It communicates with the third nerve in the cavernous sinus, and through the ciliary ganglion ; frequently with the fourth in the formation of the nerve ofthe tentorium ; with the Casserian ganglion ; with the ophthalmic division of the fifth in the cavernous sinus, and by means of the ciliary ganglion ; with the superior maxillary, through the spheno-palatine gan- glion ; and with the inferior maxillary, through the otic ganglion. It sends two branches directly to the sixth nerve, which unite* with it as it crosses the cavernous sinus ; it communicates with the facial and auditory nerves, throuo-h the medium of the petrosal branch of the Vidian ; and with the glosso-pharyngeal by means of two filaments to the tympanic nerve. CERVICAL GANGLIA. The Superior cervical ganglion is long and fusiform, of a greyish colour, smooth, and of considerable thickness, extending from within an inch of * Panizza in his "Experimental Researches on the Nerves/' denies this communica- tion and states very vaguely that " they are merely lost and entwined abound it."— Edinburgh Medical and Surgical Journal January 1S36. °31* 438 INFERIOR CERVICAL GANGLION. the carotid foramen in the petrous bone to opposite the lower border of the third cervical vertebra. It is in relation in front with the sheath of the internal carotid artery and internal jugular vein; and behind with the rectus anticus major muscle. Its branches, like those of all the sympathetic ganglia in the trunk, are divisible into superior, inferior, external, and internal; to which may be added, as proper to this ganglion, anterior. The superior (carotid nerve) is a single branch which ascends by the side of the internal carotid, and divides into two branches; one lying to the outer side, the other to the inner side of that vessel. The two branches enter the carotid canal, and by their communications with each other and with the petrosal branch of the Vidian, constitute the carotid plexus. The inferior or descending branch, sometimes two, is the cord of com- munication with the middle cervical ganglion. The external branches are numerous, and may be divided into two sets: those w7hich communicate with the glosso-pharyngeal, pneumogastric, and hypoglossal nerves; and those which communicate with the three first cervical nerves. The internal branches are three in number: pharyngeal, to assist in forming the pharyngeal plexus; laryngeal, to join the superior laryngeal nerve and its branches; and the superior cardiac nerve, or nervus super- ficialis cordis. The anterior branches accompany the carotid artery with its branches, around which they form intricate plexuses, and here and there small gan- glia; they are called, from the softness of their texture, nervi molles, and from their reddish hue, nervi subrufi. The Middle cervical ganglion (thyroid ganglion) is of small size, and sometimes altogether wanting. It is situated opposite the fifth cervical vertebra, and rests upon the inferior thyroid artery. This relation is so constant, as to have induced Haller to name it the "thyroid ganglion." Its superior branch, or branches, ascend to communicate with the supe- rior cervical ganglion. Its inferior branches descend to join the inferior cervical ganglion; one of these frequently passes in front of the subclavian artery, the other be- hind it. Its external branches communicate with the third, fourth, and fifth cer- vical nerves. Its.internal branches are, filaments which accompany the inferior thyroid artery, the inferior thyroid plexus; and the middle cardiac nerve, nervus cardiacus magnus.' The Inferior cervical ganglion (vertebral ganglion) is much larger than the preceding, and is constant in its existence. It is of a semilunar form, and is situated upon the base of the transverse process ofthe seventh cervical vertebra, immediately behind the vertebral artery: hence its title to the designation " vertebral ganglion." Its superior branches communicate with the middle cervical ganglion. The inferior branches pass some before and some behind the subclavian artery, to join the first thoracic ganglion. The external branches consist of two sets; one which communicates with the sixth, seventh, and eighth cervical and first dorsal nerve; and CARDIAC NERVES. 439 Fig. 197.f one w7hich accompanies the verte- bral artery along the vertebral ca- nal, forming the vertebral plexus. This plexus sends filaments to all the branches given off by the ar- tery, and communicates in the cranium with the filaments of the carotid plexus accompanying the branches of the internal carotid artery. The internal branch is the infe- rior cardiac nerve, nervus cardiacus minor. Cardiac Nerves.*—The supe- rior cardiac nerve (nervus superfi- dalis cordis) arises from the lower part of the superior cervical gan- glion ; it then descends the neck behind the common carotid artery and parallel with the trachea, crosses the inferior thyroid artery, and running by the side of the re- current laryngeal nerve for a short distance, passes behind the arteria innominata to the concavity of the arch of the aorta, where it joins the cardiac ganglion. In its course it receives branches from the pneumogastric nerve, and sends filaments to the thyroid gland and trachea. The Middle cardiac nerve (ner- vus cardiacus magnus) proceeds from the middle cardiac ganglion, or, in its absence, from the cord of communication between the superior and inferior. It is the largest of the three nerves, and lies nearly parallel with the recurrent * There is no constancy with regard to the origin and course of these nerves; there- fore the student must not be disappointed in finding the description in discord with his dissection. . „ f A view of the great sympathetic nerve. 36. The cavity of the cranium. 34. Ihe globe of the eye 33. The septum of the nose. 32. The incisor teeth. 31. The sub- maxillary gland 30. The larynx. 29. The heart. 28. The left lung. * The cceliac axis 27 The ascending vena cava. 26. The kidney. 25. The crista of the ilium. 23 The bladder. 22. The rectum. 24. The pubes. 1. Plexus on the carotid artery in the carotid foramen. 2. Sixth nerve, (motor externus.) 3. 1st of the fifth or ophthal- mic nerve 4 Branch on the septum narium, connecting Meckel's ganglion with Clo- quets in the incisive foramen. 5. Immediately above the figure is the recurrent branch or Vidian nerve, dividing into the carotid and petrosal branches. 6. Posterior palatine branches 7 Lingual nerve joined by the chorda tympani. S. The portio dura of the seventh pair or facial nerve. 9. The superior cervical ganglion. 10. The middle cer 440 THORACIC GANGLIA. laryngeal. At the root of the neck it divides into several branches, which pass some before and some behind the subclavian artery; it communicates with the superior and inferior cardiac, and with the pneumogastric and recurrent nerves, and descends to the bifurcation of the trachea, to the great cardiac plexus. The Inferior cardiac nerve (nervus cardiacus minor) arises from the in- ferior cervical ganglion, communicates freely with the recurrent laryngeal and middle cardiac nerves, and descends to the front of the bifurcation ofthe trachea, to join the great cardiac plexus. The Cardiac ganglion is a ganglionic enlargement of variable size, situ- ated beneath the arch of the aorta, to the right side of the ligament of the ductus arteriosus. It receives the superior cardiac nerves of opposite sides of the neck and a branch from the pneumogastric, and gives off nu- merous branches to the cardiac plexuses. v The Great cardiac plexus is situated upon the bifurcation of the trachea, above the right pulmonary artery, and behind the arch of the aorta. It is formed by the convergence of the middle and inferior cardiac nerves, and by branches from the pneumogastric and descendens noni nerve, and first thoracic ganglion. The Anterior cardiac plexus is situated in front of the ascending aorta, near its origin. It is formed by the communications of filaments that pro- ceed from three different sources, namely, from the superior cardiac nerves, crossing the arch of the aorta ; from the cardiac ganglion beneath the arch ; and from the great cardiac plexus, passing between the ascending aorta and the right auricle. The anterior cardiac plexus supplies the an- terior aspect of the heart, distributing numerous filaments with the left coronary artery, which form the anterior coronary plexus. The Posterior cardiac plexus is formed by numerous branches from the great cardiac plexus, and is situated upon the posterior part of the ascend- ing aorta, near its origin. It divides into two sets of branches: one set accompanying the right coronary artery in the auriculo-ventricular sulcus; the other set joining the artery on the posterior aspect ofthe heart. They both together constitute the posterior coronary plexus. The great cardiac plexus likewise gives branches to the auricles of the heart, and others to assist in forming the anterior and posterior pulmonary plexuses. thoracic ganglia. The Thoracic ganglia are twelve in number on each side. They are flattened and triangular, or irregular in form, and present the peculiar grey colour and pearly lustre of the other sympathetic ganglia; they rest upon the heads of the ribs, and are covered in by the pleura costalis. The two first ganglia and the last are usually the largest. Their branches are superior, inferior, external, and internal. The superior and inferior are prolongations of the substance of the gan- glia rather than branches ; the former to communicate with the ganglion above, the latter with that below. vical ganglion. 11. The inferior cervical ganglion. 12. The roots of the great splanch- nic nerve, arising from the dorsal ganglia. 13. The lesser splanchnic nerve. 14. The lenal plexus. 15. The solar plexus. 16. The mesenteric plexus. 17. The lumbar ganglia. 18. The sacral ganglia. 19. The vesical plexus. 20. The rectal plexus. 2L The lumbar plexus, (cerebro-spinal.) LUMBAR GANGLIA. 441 The external branches, two or three in number, communicate with both roots of each of the spinal nerves. The internal branches of the five upper ganglia are pulmonary to join the pulmonary plexuses; oesophageal to the oesophageal plexus and aortic to the thoracic aorta and its branches; the first thoracic ganglion more- over sends branches to the cardiac plexuses. The branches of the lower ganglia are aortic, and several large cords which unite to form the two splanchnic nerves. The Great splanchnic nerve arises from the sixth dorsal ganglion, and receives branches from the seventh, eighth, ninth, and tenth, which aug- ment it to a nerve of considerable size. It descends in front of the verte- bral column, within the posterior mediastinum, pierces the diaphragm immediately to the outer side of each crus, and terminates in the semilunar ganglion. The Lesser splanchnic nerve (renal) is formed by filaments from the tenth, eleventh, and sometimes from the twelfth dorsal ganglion. It pierces the diaphragm, and descends to join the renal plexus. The Semilunar ganglion is a large, irregular, gangliform body, pierced by numerous openings, and appearing like the aggregation of a number of smaller ganglia, having spaces between them. It is situated by the side of the ccelic axis, and communicates with the ganglion of the oppo- site side, both above and below that trunk, so as to form a gangliform circle, from which branches pass off in all directions, like rays from a centre. Hence the entire circle has been named the solar plexus. The Solar plexus receives the great splanchnic nerves; part of the lesser splanchnic nerves ; the termination of the right pneumogastric nerve ; some branches from the right phrenic nerve; and sometimes one or two fila- ments from the left. It sends numerous filaments, which accompany, under the name of plexuses, all the branches given off by the abdominal aorta. Thus, we have derived from the solar plexus the— Phrenic plexuses, Renal plexuses, Gastric plexus, Superior mesenteric plexus, Hepatic plexus, Spermatic plexuses, Splenic plexus, Inferior mesenteric plexus. Supra-renal plexuses, The Renal plexus is formed chiefly by the lesser splanchnic nerve, but receives many filaments from the solar plexus. The Spermatic plexus is formed principally by the renal plexus. The Inferior mesenteric plexus receives filaments from the aortic plexus. LUMBAR GANGLIA. The Lumbar ganglia are four in number on each side, of the peculiar pearly grey colour, fusiform, and situated upon the anterior part of the bodies of the lumbar vertebras. The superior and inferior branches of the lumbar ganglia are branches of communication with the ganglion above and below, as in the dorsal ^ The' external branches, two or three in number, communicate with the lumbar nerves. . The infernal branches constst of two sets; of which the upper pass in wards in front of the abdominal aorta, and form around that trunk a plex 442 ORGANS OF SENSE. iform interlacement, which constitutes the lumbar aortic plexus; the lower branches cross the common iliac arteries, and unite over the promontory of the sacrum, to form the hypogastric plexus. The Lumbar aortic plexus is formed by branches from the lumbar gan- glia, and receives filaments from the solar and superior mesenteric plex- uses. It sends filaments to the inferior mesenteric plexus, and terminates in the hypogastric plexus. The Hypogastric plexus is formed by the termination of the aortic plexus, and by the union of branches from the lower lumbar ganglia. It is situated over the promontory of the sacrum, between the two common iliac arteries, and bifurcates inferiorly into two lateral portions, which communicate with branches from the fourth and fifth sacral nerves. It distributes branches to all the viscera of the pelvis, and sends filaments which accompany the branches of the internal iliac artery. SACRAL GANGLIA. The Sacral ganglia are four or five in number on each side. They are situated upon the sacrum, close to the anterior sacral foramina, and re- semble the lumbar ganglia in form and mode of connexion, although much smaller in size. The superior and inferior branches communicate with the ganglia above and below. The external branches communicate with the sacral nerves. The internal branches communicate very freely with the lateral divisions of the hypogastric plexus, and are distributed to the pelvic viscera. The last pair of sacral ganglia give off branches which join a small ganglion, situated on the first bone of the coccyx, called the ganglion impar, or azygos. This ganglion resembles in its position and function the ganglion of Ribes, serving to connect the inferior extremity of the sympathetic sys- tem, as does the former ganglion its upper extremity. It gives off a few small branches to the coccyx and rectum. CHAPTER X. ORGANS OF SENSE. The organs of sense, the instruments by which the animal frame is brought into relation with surrounding nature, are five in number. Four of these organs are situated within the head: viz. the apparatus of smell, sight, hearing, and taste; and the remaining organ, of touch, is resident in the skin, and distributed over the surface of the body. THE NOSE AND NASAL F O S S JE . The organ of smell consists essentially of tw7o parts: one external, the nose; the other internal, the nasal fossa. The nose is the triangular pyramid which projects from the centre of the face, immediately above the upper lip. Superiorly it is connected STRUCTURE OF THE NOSE. 443 with the forehead by means of a narrow bridge ; inferiorly, it presents two openings, the nostrils, which overhang the mouth, and are so constructed that the odour of all substances must be received by the nose before they can be introduced within the lips. The septum between the openings of the nostrils is called the columna. Their entrance is guarded by a num- ber of stiff hairs (vibrissa) w7hich project across the openings, and act as a filter in preventing the introduction of foreign substances, such as dust or insects, with the current of air intended for respiration. The anatomical elements of which the nose is composed, are—1. In- tegument. 2. Muscles. 3. Bones. 4. Fibro-cartilages. 5. Mucous membrane. 6. Vessels and nerves. 1. The Integument forming the tip (lobulus) and wings (ale) ofthe nose is extremely thick and dense, so as to be with difficulty separated from the fibro-cartilage. It is furnished with an abundance of sebiparous folli- cles, which, by their oily secretion, protect the extremity of the nose in excessive alternations of temperature. The sebaceous matter of these fol- licles becomes of a dark colour upon the surface, from the attraction of the carbonaceous matter floating in the atmosphere; hence the spotted ap- pearance which the tip of the nose presents in large cities. When the integument is firmly compressed, the inspissated sebaceous secretion is squeezed out from the follicles, and taking the cylindrical form of their excretory ducts, has the appearance of small white maggots with black heads. 2. The Muscles are brought into view by reflecting the integument: they are the pyramidalis nasi, compressor nasi, dilatator naris, levator labii superioris alaeque nasi, and depressor labii superioris alaeque nasi. They have been already described with the muscles of the face. 3. The Bones of the nose are, the nasal, and nasal processes of the su- perior maxillary. 4. The Fibro-cartilages give form and stability to the outwork of the nose, providing, at the same time, Fis- 198 by their elasticity, against injuries. They are five in number, namely, the— Fibro-cartilage of the septum, Two lateral fibro-cartilages, Two alar fibro-cartilages. The Fibro-cartilage of the septum, somewhat trian- gular in form, divides the nose into its two nostrils. It is connected above with the nasal bones and lateral fibro-cartilages ; behind, with the ethmoidal septum and vomer; and below, with the palate processes of the superior maxillary bones. The alar fibro-carti- lages and columna move freely upon the fibro-cartilage ofthe septum, being but loosely connected with it by perichondrium. The Lateral fibro-cartilages are also triangular: they are connected, in front, with the fibro-cartilage of the septum ; above, with the nasal bones; » The fibro-cartilages ofthe nose. 1. One ofthe nasal bones. 2. The fibro-cartilage •\f the septum 3 The lateral fibro-cartilage. 4. The alar fibro-cartilage. 5. The central portions of the alar fibro-cartilages which constitute the columna. 6. The ap- pendix ofthe alar fibro-cartilage. 7. The nostril. centra r. c ■lo 444 NASAL FOSSAE. behind, with the nasal processes of the superior maxillary bones ; and below with the alar fibro-cartilages. Alar fibro-cartilages.—Each of these cartilages is curved in such a man- ner as to correspond with the opening of the nostril, to which it form- a kind of rim. The inner portion is loosely connected with the same p;irt of the opposite cartilage, so as to form the columna. It is expanded and thickened at the point of the nose to constitute the lobe; and on the side forms a curve corresponding with the form ofthe ala. This curve is pro- longed downwards and forwards in the direction of the posterior border of the ala by three or four small fibre-cartilaginous plates, which are ap- pendages of the alar fibro-cartilage. The whole of these fibro-cartilages are connected with each other and to the bones, by perichondrium, which, from its membranous structure, permits ofthe freedom of motion existing between them. 5. The Mucous membrane, lining the interior of the nose, is continuous with the skin externally, and with the pituitary membrane of the nasal fossae within. Around the entrance of the nostrils it is provided with numerous vibrisse. 6. Vessels and Nerves. — The Arteries of the nose are the lateralis nasi from the facial, and the nasalis septi from the superior coronary. Its Nerves are, the facial, infra-orbital, and nasal branch of the oph- thalmic. NASAL FOSS i£. To obtain a good view of the nasal fosse, the face must be divided through the nose by a vertical incision, a little to one side of the middle line. The Nasal fosse are two irregular compressed cavities, extending back- wards from the nose to the pharynx. They are bounded superiorly by the lateral cartilage of the nose, and by the nasal, sphenoid, and ethmoid bones; inferiorly by the hard palate; and, in the middle line, they are separated from each other by a bony and nbro-cartilaginous septum. A plan ofthe boundaries ofthe nasal fossae will be found at page 91. Upon the outer wall of each fossa, in the dried skull, are three project- ing processes, termed spongy bones. The two superior belong to the ethmoid, the inferior is a separate bone. In the fresh fossae these are covered with mucous membrane, and serve to increase the surface of that membrane by their prominence and convoluted form. The space inter- vening between the superior and middle spongy bone is the superior meatus; the space between the middle and inferior the middle meatus; and that between the inferior and the floor of the fossa the inferior meatus. These meatuses are passages which extend from before backwards, and it is in rushing through and amongst these that the atmosphere deposits its odprant particles upon the mucous membrane. There are several openings into the nasal fossae: thus, in the superior meatus are the openings of the sphenoidal and posterior ethmoidal cells ; in the middle the anterior ethmoidal cells, the frontal sinuses, and the antrum maxillare ; and, in the inferior meatus, the termination of the nasal duct. In the dried bone there are two additional openings, the spheno-palatine and the anterior palatine foramen ; the former being situated in the superior, and the latter in the inferior meatus. EYE--SCLEROTIC COAT. 445 The Mucous membrane of the nasal fossae is called pituitary, or Schnri- derian* The former name being derived from the nature of its secretion, the latter from Schneider, who was the first to show that the secretion of the nose proceeded from the mucous membrane, and not from the brain, as was formerly imagined. It is continuous with the general gastro-pul- monary mucous membrane, and may be traced through the openings in the meatuses, into the sphenoidal and ethmoidal cells ; into the frontal sinuses; into the antrum maxillare ; through the nasal duct to the surface of the eye, where it is continuous with the conjunctiva; along the Eusta- chian tubes into the tympanum and mastoid cells, to which it forms the lining membrane ; and through the posterior nares into the pharynx and mouth, and thence through the lungs and alimentary canal. The surface of this membrane is furnished with a columnar epithelium supporting innumerable vibratile cilia. Ves^h and Nerves. — The Arteries of the nasal fossae are the anterior and postenoi ethmoidal, from the ophthalmic artery; and the spheno- palatine and pterygo-palatine from the internal maxillary. The Nerves are, the olfactory, the spheno-palatine branches from Meckel's ganglion, and the nasal branch ofthe ophthalmic. The ultimate filaments of the olfactory nerve terminate in papillae. THE EYE, WITH ITS APPENDAGES. The form of the eyeball is that of a sphere, of about one inch in diame- ter, having the segment of a smaller sphere engrafted upon its anterior surface, which increases its antero-posterior diameter. The axes of the two eyeballs are parallel with each other, but do not correspond with the axes of the orbits, which are directed outwards. The optic nerves follow the direction of the orbits, and therefore enter the eyeballs to their nasal side. The Globe of the Eye is composed of tunics, and of refracting media called humours. The tunics are three in number, the 1. Sclerotic and Cornea, 2. Choroid, Iris, and Ciliary processes, 3. Retina and Zonula ciliaris. The humours are also three— Aqueous, Crystalline (lens), Vitreous. First tunic—The Sclerotic and Cornea form the external tunic of the eyeball, and give it its peculiar form. Four-fifths ofthe globe are invested by the sclerotic, the remaining fifth by the cornea. The Sclerotic (te-h^k, hard) is a cense fibrous membrane, thicker behind than in front It is continuous, pos teriorly, with the sheath of the optic nerve which is derived from the du ra mater, and is pierced by that nerve as we'll as by the ciliary nerves a: d arteries. Anteriorly it presents a bevelled edge which receives the c i>rnea in the same way that a watch- • Conrad Victor Schneider, professor of. fedicine at W. tenberg. His work, entitled De Catarrhis, &c. was published in 1}6J. 38 446 STRUCTURE OF THE CORNEA. glass is received by the groove in its case. Its anterior surface is covered by a thin tendinous layer, the tunica albuginea, derived from the expansion of the tendons of the four recti muscles. By its posterior surface it gives attachment to the two oblique muscles. The tunica albuginea is covered, for a part of its extent, by the mucous membrane of the front of the eye, the conjunctiva; and, by reason of the brilliancy of its whiteness, gives occasion to the common expression, "the white ofthe eye." At the entrance of the optic nerve, the sclerotic forms a thin cribriform lamella (lamina cribrosa), w-hich is pierced by a number of minute open- ings for the passage of the nervous filaments. One of these openings, larger than the rest, and situated in the centre of the lamella, is the porus opticus through which the arteria centralis retinae enters the eyeball. Fig. 199.* The Cornea (corneus, horny) is the transparent projecting layer that constitutes the anterior fifth of the globe of the eye. In its form it is cir- cular, concavo-convex, and resembles a watch-glass. It is received by its edge, which is sharp and thin, within the bevelled border of the scle- rotic, to which it is very firmly attached, and it is somewhat thicker than the anterior portion of that tunic. When examined from the exterior, its vertical diameter is seen to be about one-sixteenth shorter than the trans- verse, in consequence of the overlapping above and below, of the margin of the sclerotica; on the interior, however, its outline is perfectly circular. The cornea is composed of four layers: namely, ofthe conjunctiva; of the cornea proper, which consists of several thin lamellae connected together by an extremely fine areolar tissue ; of the cornea elastica, a " fine, elastic, and exquisitely transparent membrane, exactly applied to the inner surface * A longitudinal section of the globe of the eye. 1. The sclerotic, thicker behind than in front. 2. The cornea, received within the anterior margin of the sclerotic, and con- nected with it by means of a bevelled edge. 3. The choroid, connected anteriorly with (4) the ciliary ligament, and (5) the ciliary processes. 6. The iris. 7. The pupil. 8. The third layer of the eye, the retina, terminating anteriorly by an abrupt border at the commencement of the ciliary processes. 9. The canal of Petit, which encircles the lens (12) ; the thin layer in front of this canal is the zonula ciliaris, a prolongation of the vascular layer of the retina to the lens. 10. The anterior chamber of the eye, con- taining the aqueous humour: the lining membrane by which the humour is secreted is represented in the diagram. 11. The posterior chamber. 12. The lens, more convex behind than before, and enclosed in its proper capsule. 13. The vitreous humour en- closed in the hyaloid membrane, and in cells formed in its interior by that membrane. 14. A tubular sheath of the hyaloid membrane, which serves for the passage of the artery of the capsule of the lens. 15. The neurilemma of the optic nerve. 16. The arteria centralis retinae, embedded in the centre of the optic nerve. SECOND TUNIC. 447 ofthe cornea proper," and of the lining membrane of the anterior chamber of the eyeball. The cornea elastica is remarkable for its perfect transpa- rency, even when submitted for many days to the action of water or alco- hol ; while the cornea proper is rendered opaque by the same immersion. To expose this membrane, Dr. Jacob suggests that the eye should be placed in water for six or eight days, and, then, that all the opaque cornea should be removed layer after layer. Another character of the cornea elastica is its great elasticity, which causes it to roll up when divided or torn, in the same manner as the capsule of the lens. The use of this layer, according to Dr. Jacob, is to " preserve the requisite permanent correct curvature ofthe flaccid cornea proper." The opacity of the cornea, produced by pressure on the globe, results from the infiltration of fluid into the areolar tissue connecting its layers. This appearance cannot be produced in a sound living eye. Dissection.—The sclerotic and cornea are now to be dissected away from the second tunic ; this, with care, may be easily performed, the only connexions subsisting between them being at the circumference of the iris, the entrance of the optic nerve, and the perforation of the ciliary nerves and arteries. Pinch up a fold of the sclerotic near its anterior circumfer- ence, and make a small opening into it, then raise the edge of the tunic, and with a pair of fine scissors, having a probe point, divide the entire circumference of the sclerotic, and cut it away bit by bit. Then separate it from its attachment around the circumference of the iris by a gentle pressure with the edge of the knife. The dissection of the eye must be conducted under water. In the course of this dissection the ciliary nerves and long ciliary arteries will be seen passing forwards between the sclerotic and choroid to be dis- tributed to the iris. Second tunic.—The second tunic of the eyeball is formed by the cho- roid, ciliary ligament, and iris, the ciliary processes being an appendage developed from its inner surface. The Choroid* is a vascular membrane of a rich chocolate-brown colour upon its external surface, and of a deep black colour within. It is con- nected to the sclerotic, externally, by an extremely fine areolar tissue, and by nerves and vessels. Internally it is in simple contact with the third tunic of the eye, the retina. It is pierced posteriorly for the passage of the optic nerve, and is connected anteriorly with the iris, ciliary processes, and with the line of junction of the cornea and sclerotic, by a dense white structure, the dliary ligament, which surrounds the circumference of the iris like a ring. The choroid membrane is composed of three layers:—an external or venous layer, which consists principally of veins arranged in a peculiar manner: hence they have been named vence vorticose. The marking on * The word choroid has been very much abused in anatomical language ; it was origi- nally applied to'the membrane ofthe foetus called chorion from the Greek word x6pt,ov, domicilium that membrane being, as it were, the abode or receptacle of the fistus. Xdptov comes from *««««, to take or receive. Now it so happens that the chorion in the ovum is a vascular membrane of peculiar structure. Hence the term choroid, yoaio fv6o< like the chorion, has been used indiscriminately to signify vascular structures, as in'the choroid membrane of the eye, the choroid plexus, &,c., and we find Cruveil- hier in his work on Anatomy, vol. iii. p. 463, saying in a note, " Choroide est synonyme de vasculeuse." 448 CILIARY LIGAMENT—IRIS. the surface of the membrane pro- duced by these veins resembles so many centres to which a number of curved lines converge. It is this layer which is connected with the ciliary ligament. The middle or ar- terial layer (tunica Ruyschiana]) is 5 formed principally by the ramifica- tions of minute arteries. It is re- flected inwards at its junction with the ciliary ligament, so as to form the ciliary processes. The internal layer is a delicate membrane (mem- brana pigmenti) composed of seve- ral laminae of nucleated hexagonal cells, which contain the granules of pigmentum nigrum, and are arranged so as to resemble a tesselated pavement. In animals, the pigmentum nigrum, on the posterior wall ofthe eyeball, is replaced by a layer of considerable extent, and of metallic brilliancy called the tapetum. The Ciliary ligament, or circle, is the bond of union between the ex- ternal and middle tunics of the eyeball, and serves to connect the cornea and sclerotic, at their line of junction, with the iris and external layer of the choroid. It is also the point to which the ciliary nerves and vessels proceed previously to their distribution, and it receives the anterior ciliary arterie? iV ough the anterior margin of the sclerotic. A minute vascular canal i; r.iuated within the ciliary ligament, called the ciliary canal, or the canal of Fontana,| from its discoverer. The Iris (iris, a rainbow,) is so named from its variety of colour in dif- ferent individuals: it forms a septum between the anterior and posterior chambers of the eye, and is pierced somewhat to the nasal side of its centre by a circular opening, which is called the pupil. By its periphery it is connected with the ciliary ligament, and by its inner circumference forms the margin of the pupil; its anterior surface looks towards the cornea, and the posterior towards the ciliary processes and lens. The iris is composed of two layers, an anterior or muscular, consisting of radiating fibres which converge from the circumference towards the centre, and have the power of dilating the pupil; and circular, which sur- round the pupil like a sphincter, and by their action produce contraction * A dissection of the eyeball, showing its second tunic, and the mode of distribution ofthe venae vorticosae ofthe choroid. After Arnold. 1. Part of the sclerotic coat. 2. The optic nerve. 3, 3. The choroid coat. 4. The ciliary ligament. 5. The iris. 6, 6. The venae vorticosae. 7, 7. The trunks of the venae vorticosae at the point where they have pierced the sclerotica. 8, 8. The posterior ciliary veins, which enter the eyeball n company with the posterior ciliary arteries, by piercing the sclerotic at 9. 10. One ofthe long ciliary nerves, accompanied by a long ciliary vein. | Ruysch was born at the Hague in 1638, and was appointed professor of Anatomy at Amsterdam in 1665. His whole life was employed in making injected preparations, for which he is justly celebrated, and he died at the advanced age of ninety-three years. He came to the conclusion that the body was entirely made up of vessels. t Felix Fontana, an anatomist of Tuscany. His " Description of a New Canal in the Eye," was published in 1778, in a Letter to the Professor of Anatt my in Upsal. THIRD TUNIC. 449 of its area. The posterior layer is of a deep purple tint, and is thence named uvea, from its resemblance in colour to a ripe grape. The Ciliary processes may be seen in two ways, either by removing the iris from its attachment to the ciliary ligament, when a front view of the processes will be obtained, or by making a transverse section through the globe of the eye, when they may be examined from behind, as in fig. 201. The ciliary processes consist of a number of triangular folds, formed apparently by the plaiting of the middle and internal layer of the choroid. According to Zinn, they are about sixty in number, and may be divided into large and small, the latter being situated in the spaces between the former. Their periphery is connected with the ciliary ligament, and is continuous with the middle and internal layer of the choroid. The central border is free, and rests against the circumference of the lens. The ante- rior surface corresponds with the uvea; the posterior receives the folds of the zonula ciliaris between its processes, and thus establishes a connexion between the choroid and the third tunic of the eye. The ciliary processes are covered with a thick layer of pigmentum nigrum, which is more abundant upon them, and upon the anterior part of the choroid, than upon the posterior part. When the pigment is washed off, the processes are of a whitish colour. Fig. 201* Fig. 202.f Third Tunic —The third tunic of the eye is the retina, which is pro- longed forwards to the lens by the zonula ciliaris. Dissection. — If, after the preceding dissection, the choroid membrane be carefully raised and removed, the eye being kept under water, the retina may be seen very distinctly. * The anterior segment of a transverse section of the globe of the eye seen from within 1 The divided edge of the three tunics; sclerotic, choroid (the dark layer), and retina 2 The pupil. 3. The iris, the surface presented to view in this section being the uvea. 4. The ciliary processes. 5. The scalloped anterior border of the retina. + The nosterior segment of a transverse section of the globe of the eye, seen from within 1 The divided edge of the three tunics. The membrane covering the whole . , * . t. _ rpt;na 9 The entrance of the optic nerve with the arteria cen- internal surface i the etina 2.Ae nt ^ ^ fhe arferia ^^ 4 The trails 'etina piercing its centre , ghade ^^ SHec :X^ 'HmbT luteu., which surround^ i . , A fo.d of the retin. Which Generally obscures the foramen of Soemmering after the eye has been opened. °38* 2d 450 RETINA--STRUCTURE. The Retina is composed of three layers:— External, or Jacob's membrane, Middle, Nervous membrane, Internal, Vascular membrane. Jacob's membrane is extremely thin, and is seen as a mere film when the freshly dissected eye is suspended in water. Examined by the micro- scope, it is found to be composed of cells having a tesselated arrangement. Dr. Jacob considers it to be a serous membrane. The Nervous membrane is the expansion of the optic nerve, and forms a thin semi-transparent bluish-white layer, which envelopes the vitreous humour, and extends forwards to the commencement of the ciliary pro- cesses, where it terminates by an abrupt scalloped margin. According to Treviranus, this layer is composed of cylindrical fibres, which proceed from the optic nerve, and, near their termination, bend abruptly inwards, to form the internal papillary layer, which lies in contact with the hyaloid membrane; each fibre constituting by its extremity a distinct papilla. The Vascular membrane consists of the ramifications of a minute artery, the arteria centralis retinae, and its accompanying vein; the artery pierces the optic nerve, and enters the globe of the eye through the poms opticus, in the centre of the lamina cribrosa. This artery may be seen very dis- tinctly by making a transverse section of the eyeball. Its branches are continued anteriorly into the zonula ciliaris. The vascular layer forms distinct sheaths for the nervous papillae, which constitute the inner surface of the retina. In the centre of the posterior part of the globe of the eye the retina pre- sents a circular spot, which is called the foramen of Soemmering ;* it is surrounded by a yellow7 halo, the limbus luteus, and is frequently obscured by an elliptical fold of the retina, which has been regarded as a normal condition of the membrane. The term foramen is misapplied to this spot, for the vascular layer and the membrana Jacobi are continued across it; the nervous substance alone appearing to be deficient. It exists only in animals having the axes of the eyeballs parallel with each other, as man, quadrumana, and some saurian reptiles, and is said to give passage to a small lymphatic vessel. The Zonula ciliaris (zonula of Zinn)f is a thin vascular layer, which connects the anterior margin of the retina with the anterior surface of the lens near its circumference. It presents upon its surface a number of small folds corresponding with the ciliary processes, between which they are received. These processes are arranged in the form of rays around the lens, and the spaces between them are stained by the pigmentum nigrum of the ciliary processes. They derive their vessels from the vas- cular layer of the retina. The under surface of the zonula is in contact with the hyaloid membrane, and around the lens forms the anterior fluted wall of the canal of Petit. * Samuel Thomas Soemmering is celebrated for the beautiful and accurate plates which accompany his works. The account " De Foramine Centrali Retinae Humanse, Limbo Luteo cincto," was published in 1779, in the Commentationes Soc. Reg. Scient. Gottingensis. -(■John Gottfried Zinn, professor of Anatomy in Gottingen; his "Descriptio Anatomica Oculi Hurnani" was published in 1755, with excellent plates. It was republished hy Wrisberg in 1780. HUMOURS. 451 The connexion between these folds and the ciliary processes may be very easily demonstrated by dividing an eye transversely into two por- tions, then raising the anterior half, and allowing the vitreous humour to separate from its attachment by its own weight. The folds of the zonula will then be seen to be drawn out from between the folds of the ciliary processes. Humours.—The Aqueous humour is situated in the anterior and poste- rior chambers ofthe eye; it is a weakly albuminous fluid, having an alka- line reaction, and a specific gravity very little greater than that of distilled water. According to Petit, it scarcely exceeds four or five grains in weight. The anterior chamber is the space intervening between the cornea in front, and the iris and pupil behind. The posterior chamber is the narrow space, less than half a line in depth,* bounded by the posterior surface of the iris and pupil in front, and by the ciliary processes, zonula ciliaris, and lens behind. The two chambers are lined by a thin layer, the secret- ing membrane ofthe aqueous humour. The Vitreous humour forms the principal bulk of the globe of the eye. It is an albuminous and highly transparent fluid, enclosed in a delicate membrane, the hyaloid. From the inner surface of this membrane, nu- merous thin lamellae are directed inwards, and form compartments in which the fluid is contained. According to Hannover, these lamellse have a radiated arrangement, like those on the transverse section of an orange, and are about 180 in number. In the centre of the vitreous humour is a tubular canal, through which a minute artery is conducted from the arteria centralis retinae to the capsule ofthe lens. This vessel is injected without difficulty in the foetus. The Crystalline humour or lens is situated immediately behind the pu- pil, and is surrounded by the ciliary processes, which slightly overlap its margin. It is more convex on the posterior than on the anterior surface, and is embedded in the anterior part of the vitreous humour, from which it is separated by the hyaloid membrane. It is invested by a peculiarly transparent and elastic membrane, the capsule ofthe lens, which contains a small quantity of fluid, called liquor Morgagni,\ and is retained in its place by the attachment of the zonula ciliaris. Dr. Jacob is of opinion that the lens is connected to its capsule by means of areolar tissue, and that the liquor Morgagni is the result of a cadaveric change. The lens consists of concentric layers, of w7hich the external are soft, the next firmer, and the central form a hardened nucleus. These layers are best demonstrated by boiling, or by immersion in alcohol, when they separate easily from each other. Another division of the lens takes place at the same time : it splits into three triangular segments, which have the sharp edge directed towards the centre, and the base towards the circum- ference. The concentric lamellae are composed of minute parallel fibres, which are united with each other by means of scalloped borders, the con- • Winslow and Lieutaud thought the iris to be in contact with the lens; it frequently adheres to the capsule of the latter in iritis. The depth of the posterior chamber is greater in old than in young persons. f John Baptist Morgagni was born in 1682. He was appointed Professor of Medi- cine in Bologna, and published the first part of his "Adversaria Anatomica" in 1706. He died in 1771. 452 ARTERIA CENTRALIS RETINAE. vexity on the one border fitting accurately the concave scallop upon the other. Immediately around the circumference of the lens is a triangular canal, the canal of Petit* about a line and a half in breadth. It is bounded, in front, by the flutings of the zonula ciliaris; behind, by the hyaloid mem- brane ; and, within, by the border of the lens. The Vessels of the globe of the eye are the long and short, and anterior ciliary arteries, and the arteria centralis retinae. The long ciliary arteries, tw-o in number, pierce the posterior part of the sclerotic, and pass forward on each side, between that membrane and the choroid, to the ciliary liga- ment, where they divide into two branches, which are distributed to the iris. The short ciliary arteries pierce the posterior part of the sclerotic coat, and are distributed to the middle layer of the choroid membrane. The anterior ciliary are branches of the muscular arteries. They enter the eye through the anterior part of the sclerotic, and are distributed to the iris. It is the increased number of these latter arteries, in iritis, that gives rise to the peculiar red zone around the circumference of the cornea which accompanies that disease. The arteria centralis retine enters the optic nerve at about half an inch from the globe ofthe eye, and passing through the poms opticus is distri- buted upon the inner surface of the retina, forming its vascular layer; one branch pierces the centre of the vitreous humour, and supplies the capsule of the lens. The Nerves of the eyeball are, the optic, two ciliary nerves from the nasal branch of the ophthalmic, and the cdiary nerves from the ciliary ganglion. Observations. — The sclerotic is a tunic of protection, and the cornea a medium for the transmission of light. The choroid supports the vessels destined for the nutrition of the eye, and by its pigmentum nigrum absorbs all loose and scattered rays that might confuse the image impressed upon the retina. The iris, by means of its pow-ers of expansion and contraction, ;ulates the quantity of light admitted through the pupil. If the iris be fLm, and the rays of light pass through its substance, they are immediately absorbed by .he uvea ; and if that layer be insufficient, they are tak<. a up t ' the black pigment of the ciliary processes. In Albinoes, where there is an absence of pigmentum nigrum, the rays of light traverse the iris, and even the sclerotic, and so overwhelm the eye with light, that sight is de- stroyed, except in the dimness of evening or at night. In the manufacture of optical instruments care is taken to colour their interior black with the same object, the absorption of scattered rays. The transparent lamellated cornea and the humours of the eye have for their office the refraction of the rays in such proportion as to direct the image in the most favourable manner upon the retina. Where the refract- ing medium is too great, as in over convexity of the cornea and lens, the image falls short of the retina (myopia, near-sightedness); and where it is too little, the image is thrown beyond the nervous membrane (presbyopia, far-sightedness). These conditions are rectified by the use of spectacles, which provide a differently refracting medium externally to the eye, and thereby correct the transmission of light. * John Louis Petit, a celebrated French surgeon: he published several surgical and anatomical Essays, in the early part ofthe 18th century. He died in 1750. EYEBROWS—EYELIDS. 453 APPENDAGES OF THE EYE. The Appendages of the Eye (lutamina oculi) are, the eyebrows, eye- lids, eyelashes, conjunctiva, caruncula lachrymalis, and the lachrymal ap- paratus. The Eyebrows (supercilia) are two projecting arches of integument covered with short thick hairs, which form the upper boundary of the orbits. They are connected beneath with the orbiculares, occipito-fron- tales, and corrugatores superciliorum muscles; their use is to shade the eyes from too vivid a light, or protect them from particles of dust and moisture floating over the forehead. The Eyelids (palpebre) are two valvular Fig. 203* layers placed in front of the eye, serving to defend it from injury by their closure. When drawn open, they leave between them an ellip- tical space, the angles of which are called A canthi. The outer canthus is formed by the meeting of the two lids at an acute angle. The inner canthus is prolonged for a short distance inwards towards the nose, and a triangular space is left between the lids in this situation, wilich is called the lacus lachrymalis. At the commencement of the lacus lachrymalis upon each of the two lids is a small angular projection, the lachrymal papilla or tubercle; and at the apex of each papilla a small orifice (punctum lachrymale), the commencement of the lachrymal canal. The eyelids have, entering into their structure, integument, orbicularis muscle, tarsal cartilages, Meibomian glands, and conjunctiva. The tegumentary areolar tissue of the eyelids is remarkable for its loose- ness and for the absence of adipose substance ; it is particularly liabl - to serous infiltration. The fibres of the orbicularis muscle covering the ye- lid- , are extremely thin and pale. •*, cf; The Tarsal cartilages are two thin lamellae of fibro-cartilage aboutf an inch in length, which give form and support to the eyelids. The superior is of a semilunar form, about one-third of an inch in breadth at its middle, and tapering to each extremity. Its lower border is broad and flat, its upper is thin, and gives attachment to the levator palpebrae and to the fibrous membrane of the lids. The Inferior fibro-cartilage is an elliptical band, narrower than the su- perior and situated in the substance of the lower lid. Its upper border is flat and corresponds with the flat edge of the upper cartilage. The lower is held in its place by the fibrous membrane. Near the inner can- thus the tarsal cartilages terminate, at the commencement of the lacus lach- * The appendages ofthe eye. 1. The superior tarsal cartilage. 2. The lower border of the cartilage on which are seen the openings of the Meibomian glands. 3. Ihe infe- rior tarsal cartilage • along the upper border of this cartilage the openings ofthe Meibo- mian elands are likewise seen. 4. The lachrymal gland ; its superior or orbital portion. 5 Its inferior or palpebral portion. 6. The lachrymal ducts. 7 The plica semilunaris. 8. The caruncula lachrymalis. 9. The puncta lachrymaha of the lachrymal canals. 10 The superior lachrymal canal. 11. The inferior lachrymal canal. 12. Ihe lachry- 14 The dilatation of the nasal duct, where it opens into the inferior meatus of'th^ncse. 'lS. The nasal duct. 454 MEIBOMIAN GLANDS. rymalis, and are attached to the margin of the orbit by the tenao oculi. At their outer extremity they terminate at a short distance from the angle of the canthus, and are retained in their position by means of a decussa- tion ofthe fibrous structure ofthe broad tarsal ligament, called the external palpebral ligament. The Fibrous membrane of the lids is firmly attached to the periosteum, around the margin of the orbit, by its circumference, and to the tarsal cartilages by its central margin. It is thick and dense on the outer half of the orbit, but becomes thin to its inner side. Its use is to retain the tarsal cartilages in their place, and give support to the lids; hence it has been named the broad tarsal ligament. The Mdbomian glands* are embedded in the internal surface of the cartilages, and are very distinctly seen on examining the inner aspect of the lids. They have the appearance of parallel strings of pearls, about thirty in number in the upper cartilage, and somewhat fewer in the lower; and open by minute foramina on the edges of the lids. They correspond in length with the breadth of the cartilage, and are consequently longer in the upper than in the lower lid. Each gland consists of a single lengthened follicle or tube, into which a number of small clustered follicles open ; the latter are so numerous as almost to conceal the tube by which the secretion is poured out upon the margin of the lids. Occasionally an arch is formed between two of them, and produces a very graceful appearance. The edges of the eyelids are furnished with a triple row of long thick hairs, wiiich curve upwards from the upper lid, and downwards from the lower, so that they may not interlace with each other in the closure of the eyelids, and prove an impediment to the opening ofthe eyes. These are the eyelashes (cilia), important organs of defence to the sensitive surface of so delicate an organ as the eye. The Conjunctiva is the mucous membrane of the eye. It covers the whole of its anterior surface, and is then reflected upon the lids so as to form their internal layer. The duplicatures formed between the globe of the eye and the lids are called the superior and inferior palpebral sinuses, of which the former is much deeper than the inferior. Where it covers the cornea the conjunctiva is very thin and closely adherent, and no ves- sels can be traced into it. Upon the sclerotica it is thicker and less ad- herent, but upon the inner surface of the lids is very closely connected, and exceedingly vascular. It is continuous with the general gastro-pul- monary mucous membrane and sympathises in its affections, as may be observed in various diseases. From the surface of the eye it may be traced through the lachrymal ducts into the lachrymal gland ; along the edges of the lids it is continuous with the mucous lining of the Meibomian glands, and at the inner angle of the eye may be followed through the lachrymal canals into the lachrymal sac, and thence downwards through the nasal duct into the inferior meatus of the nose. The Caruncula lachrymalis is the small reddish body which occupies the lacus lachrymalis at the inner canthus of the eye. In health it presents a bright pink tint; in sickness it loses its colour and becomes pale. It consists of an assemblage of follicles similar to the Meibomian glands, embedded in a fibro-cartilaginous tissue, and is the source of the whitish secretion which so constantly forms at the inner angle of the eye. It is * Henry Meibomius, " de Vasis Palpebrarum Novis," 1666. LACHRYMAL APPARATUS. 455 covered with minute hairs which are sometimes so long as to be distinctly visible to the naked eye. Immediately to the outer side of the caruncula is a slight duplicature of the conjunctiva, called plica semilunaris, which contains a minute plate of cartilage, and is the rudiment of the third lid of animals, the membrana nictitans of birds. Vessels and Nerves.—The palpebrae are supplied internally with arteries from the ophthalmic, and externally from the facial and transverse facial. Their nerves are branches of the fifth and of the facial. LACHRYMAL APPARATUS. The Lachrymal apparatus consists of the lachrymal gland with its ex- cretory ducts ; the puncta lachrymalia, and lachrymal canals; the lachry- mal sac and nasal duct. The Lachrymal gland is situated at the upper and outer angle of the orbit, and consists of two portions, orbital and palpebral. The orbital portion, about three-quarters of an inch in length, is flattened and oval in shape, and occupies the lachrymal fossa in the orbital plate of the frontal bone. It is in contact superiorly with the periosteum, with w-hich it is closely connected by its upper and convex surface; by its inferior or con- cave surface it is in relation with the globe of the eye, and the superior and external rectus ; and by its anterior border with the broad tarsal liga- ment. By its posterior border it receives its vessels and nerves. The palpebral portion, smaller than the preceding, is situated in the upper eyelid, extending downwards to the superior margin of the tarsal cartilage. It is continuous with the orbital portion above, and is enclosed in an in- vestment of dense fibrous membrane. The secretion of the lachrymal gland is conveyed away by from eight to twelve small ducts, which run for a short distance beneath the conjunctiva, and open upon its surface by a series of pores about one-twentieth of an inch apart, situated in a curved line a little above the upper border of the tarsal cartilage. Lachrymal Canals. — The lachrymal canals commence at the minute openings, puncta lachrymalia, seen upon the lachrymal papillae of the lids at the outer extremity ofthe lacus lachrymalis, and proceed inwards to the lachrymal sac, where they terminate beneath a valvular semilunar fold of the lining membrane of the sac. The superior duct at first ascends, and then turn's suddenly inwards towards the sac, forming an abrupt angle. The inferior duct forms the same kind of angle, by descending at first, and then turning abruptly inwards. They are dense and elastic in structure, and remain constantly open, so that they act like capillary tubes in ab- sorbing the tears from the surface of the eye. The two fasciculi of the tensor tarsi muscle are inserted into these ducts, and serve to draw them inwards. . . , . The Lachrymal sac is the upper extremity of the nasal duct, and is scarcely more dilated than the rest of the canal. It is lodged in the groove of the lachrymal bone, and is often distinguished, internally, from tie nasal duct, by* a semilunar or circular valve. The sac consists of mucous membrane, but is covered in and retained in its place by a fibrous expansion derived from the tendon of the orbicularis, which is inserted into the ridge on the lachrymal bone; it ;s also covered by the tensor tarsi 456 ORGAN OF HEARING. muscle, which arises from the same ridge, and in its action upon the lachrymal canals may serve to compress the lachrymal sac. The Nasal duct is a short canal about three-quarters of an inch in length, directed downwards, backwards, and a little outwards to the infe- rior meatus of the nose, where it terminates by an expanded orifice. It is lined by mucous membrane, which is continuous with the conjunctiva above, and with the pituitary membrane ofthe nose below. Obstruction, from inflammation and suppuration of this duct, constitutes the disease called fistula lachrymalis. Vessels and Nerves. — The lachrymal gland is supplied with blood by the lachrymal branch of the ophthalmic artery, and with nerves by the lachrymal branch of the ophthalmic and orbital branch of the superior maxillary. THE ORGAN OF HEARING. The apparatus of hearing is composed of three parts; the external ear, middle ear or tympanum, and internal ear or labyrinth. The External ear consists of tw7o portions, the pinna and meatus; the former representing a kind of funnel which collects the vibrations of the atmosphere, producing sounds, and the latter a tube which conveys the vibrations to the tympanum. The Pinna presents a number of holes and hollows upon its surface, which have different names assigned to them. Thus, the external folded margin is called the helix (sXif, a fold). The elevation parallel to and in front of the helix is called antihelix (dv ?• ± j? j> j. i j. j. S Annulus ovalis, Relicts offcetal structure J Fogsa ovaJia> „, „ .7 . , C Tuberculum Loweri, Structure of the auricle . J Musculi pectinati. The Superior cava returns the blood from the upper half of the body, and opens into the upper and front part ofthe auricle. The Inferior cava returns the blood from the lower half of the body, and opens through the lower and posterior wall, close to the partition between the auricles (septum auricularum). The direction of these two vessels is such, that a stream forced through the superior cava would be directed towards the auriculo-ventricular opening. In like manner, a stream rushing upwards by the inferior cava would force its current against the septum auricularum ; this is the proper direction of the two currents during foetal life. The Coronary vein returns the venous blood from the substance of the heart; it opens into the auricle between the inferior cava and the auriculo- ventricular opening, under cover of the coronary valve. The Foramina Thebesii* are minute pore-like openings, by which the venous blood exudes directly from the muscular structure ofthe heart into the auricle, without entering the venous current. These openings are also found in the left auricle, and in the right and left ventricles. • Adam Christian Thebesius. His discovery of the openings now known by his name is contained in his " Dissertatio Medica de Circulo Sanguinis in Corde," 1708. 478 RIGHT AURICLE. The Auriculo-ventricular opening is the large opening of communica tion between the auricle and ventricle. The Eustachian* valve is a part of the apparatus of foetal circulation, and serves to direct the placental blood from the inferior cava, though the foramen ovale into the left auricle. In the adult it is a mere vestige and imperfect, though sometimes it remains of large size. It is formed by a fold of the lining membrane of the auricle, containing some muscular fibres, is situated between the opening of the inferior cava and the auriculo- ventricular opening, and is generally connected with the coronary valve. The Coronary valve is a semilunar fold of the lining membrane, stretch- ing across the mouth of the coronary vein, and preventing the reflux of the blood in the vein during the contraction of the auricle. The Annulus ovalis is situated on lg' '' the septum auricularum, opposite the termination of the inferior cava. It is the rounded margin ofthe septum, which occupies the place of the fora- men ovale of the foetus. The Fossa ovalis is an oval de- pression corresponding with the fora- men ovale in the foetus. This opening is closed at birth by a thin valvular layer, which is continuous with the left margin of the annulus, and is frequently imperfect at its upper part. The depression or fossa in the right auricle results from this arrangement. There is no fossa ovalis in the left auricle. The Tuberculum Loweri\ is the portion of auricle intervening between the openings of the superior and inferior cava. Being thicker than the walls of the veins, it forms a projec- * Bartholomew Eustachius, born at San Severino, in Naples, was Professor of Medi- cine in Rome, where he died in 1570. He was one of the founders of modern anato- my, and the first who illustrated his works with good engravings on copper. f The anatomy of the heart; the organ is viewed upon the right side. 1. The cavity of the right auricle. 2. The appendix auriculas, in the cavity of which the musculi pectinati are seen. 3. The superior vena cava, opening into the upper part ofthe right auricle. 4. The inferior vena cava. 5. The fossa ovalis; the prominent ridge sur- rounding it is the annulus ovalis. 6. The Eustachian valve. 7. The opening of the coronary vein. 8. The coronary valve. 9. The entrance of the auriculo-ventricular opening, Between the numbers 1 and 9, two or three of the foramina Thebesii are seen a The right ventricle, b. c. The cavity of the right ventricle, on the walls of which the columns carneae are seen; c is placed in the channel leading upwards to the pulmonary artery, d. e. f. The tricuspid valve; e is placed on the anterior curtain, and /, on the right curtain, g. The long columna carnea, to the apex of which the anterior arid right curtains of the tricuspid valve are connected by the chorda tendineae. h The long moderator band." i. The two columnae earner of the right curtain, k The at tachment by chordae tendineae ofthe left limb of the anterior curtain. Z, I. Chords ten dineae of the « fixed curtain" of the valve, m. The valve of the pulmonary artery. The letter of reference is placed on the inferior semilunar segment, n. The apex of the right appendix auricu 83. o The left ventricle, p. The ascending aorta, q Its arch, with the three arterial trunks which arise from the arch. r. The descending aorta. i««f u-a r' M- D- " Tractatus de Corde ; item de Motu et Colore Sanguinis," 1669. His dissections were made upon quadrupeds, and his observations relate rather to animals than to man. i«."i« RIGHT VENTRICLE. 479 tion, which was supposed by Lower to direct the blood from the superior cava into the auriculo-ventricular opening. The Musculi pectinati are small muscular columns situated in the ap- pendix auriculae. They are numerous, and are arranged parallel with each other; hence their cognomen, "pectinati," like the teeth of a comb. The Right ventricle is triangular and prismoid in form. Its anterior side is convex, and forms the larger proportion of the front of the heart. The posterior side, which is also inferior, is flat, and rests upon the dia- phragm ; the inner side corresponds with the partition betw-een the two ventricles, septum ventriculorum. The right ventricle is to be laid open by making an incision parallel with, and a little to the right of, the middle line, from the pulmonary artery in front, to the apex of the heart, and thence by the side of the middle line behind to the auriculo-ventricular opening. It contains, to be examined, two openings, the auriculo-ventricular and that of the pulmonary artery; two apparatus of valves, the tricuspid and semilunar; and a muscular and tendinous apparatus belonging to the tri- cuspid valves. They may be thus arranged :— Auriculo-ventricular opening, Opening of the pulmonary artery. Tricuspid valves, Semilunar valves. Chordae tendineae, Carneae columnar. The Auriculo-ventricular opening is surrounded by a fibrous ring, co- vered by the lining membrane of the heart. It is the opening of commu- nication between the right auricle and ventricle. The Opening ofthe pulmonary artery is situated close to the septum ventriculorum, on the left side of the right ventricle, and upon the anterior aspect of the heart. The Tricuspid valves are three triangular folds of the lining membrane, strengthened by a thin layer of fibrous tissue. They are connected by their base around the auriculo-ventricular opening; and by their sides and apices, which are thickened, they give attachment to a number of slender tendinous cords, called chordae tendineae. The chorda tendinee are the tendons of the thick muscular columns (columne carnee) which stand out from the w7alls of the ventricle, and serve as muscles to the valves. A number of these tendinous cords converge to a single muscular attach- ment. The tricuspid valves prevent the regurgitation of blood into the auricie during the contraction of the ventricle, and they are prevented from being themselves driven back by the chordae tendineae and their muscular attachments. This connexion of the muscular columns of the heart to the valves has caused their division into active and passive. The active valves are the tricuspid and mitral; the passive, the semilunar and coronary. The valves consist, according to Mr. king, of curtains, cords, and * « Fs v on the Safety Valve Function in the Right Ventricle of the Human Heart," by T. w! King. Guy's Hospital Reports, vol. ii. 480 SEMILUNAR VALVES. columns. The anterior valve or curtain is the largest, and is so placed as to prevent the filling of the pulmonary artery during the distension of the ventricle. The right valve or curtain is of smaller size, and is situated on the right side of the auriculo-ventricular opening. The third valve, or '■'•fixed curtain," is connected by its cords to the septum ventriculorum. The cords (chordae tendineae) of the anterior curtain are attached, princi- pally, to a long column (columna carnea), which is connected with the "right or thin and yielding wall of the ventricle." From the lower part of this column a transverse muscular band, the "long moderator band," is stretched to the septum ventriculorum, or "solid wall" of the ventricle. The right curtain is connected, by means of its cords, partly with the long column, and partly with its own proper column, the second column, which is also attached to the "yielding wall" of the ventricle. A third and smaller column is generally connected with the right curtain. The "fixed curtain" is so named from its attachment to the "solid wall" of the ven- tricle, by means of cords only, without fleshy columns. From this arrangement of the valves it follows, that if the right ven- tricle be over distended, the thin or "yielding wall" will give way, and carry with it the columns of the anterior and right valves. The cords connected with these columns will draw down the edges of the correspond- ing valves, and produce an opening between the curtains, through which the superabundant blood may escape into the auricle, and the ventricle be relieved from over-pressure. This mechanism is therefore adapted to fulfil the "function of a safety valve." The Columne carnee (fleshy columns) is a name expressive of the appearance of the internal walls of the ventricles, which seem formed of muscular columns interlacing in almost every direction. They are divided, according to the manner of their connexion, into three sets. 1. The greater number are attached by the whole of one side, and merely form convexities into the cavity of the ventricle. 2. Others are connected by both extremities, being free in the middle. 3. A few (columnae papillares) are attached by one extremity to the w7alls of the heart, and by the other give insertion to the chordae tendineae. The Semilunar valves, three in number, are situated around the com- mencement of the pulmonary artery, being formed by a folding of its lining membrane, strengthened by a thin layer of fibrous tissue. They are attached by their convex borders, and free by the concave, which are directed upwards in the course of the vessel, so that, during the current of the blood along the artery, they are pressed against the sides of the cylinder; but if any attempt at regurgitation ensue, they are immediately expanded, and effectually close the entrance of the tube. The margins of the valves are thicker than the rest of their extent, and each valve pre- sents in the centre of this margin a small fibro-cartilaginous tubercle, called corpus Arantii,* which locks in with the other two during the closure of the valves, and secures the triangular space that would other- wise be left by the approximation of three semilunar folds. Betw-een the semilunar valves and the cylinder of the artery are three pouches, called the pulmonary sinuses (sinuses of Valsalva). Similar * Julius Caesar Arantius, Professor of Medicine in Bologna. He was a disciple of Vesalius, one of the founders of modern anatomy. His treatise "De Humano Fcetu" was published at Rome, in 1564. LEFT VENTRICLE. 481 sinuses are situated behind the valves at the commencement of the aorta, and are larger and more capacious than those of the pulmonary artery. The Pulmonary artery commences by a scalloped border, correspond- ing with the three valves which are attached along its edge. It is con- nected to the ventricle by muscular fibres, and by the lining membrane of the heart. The Left auricle is somewhat smaller, but thicker, than the right; of a cuboid form, and situated more posteriorly. The appendix auricula is constricted at its junction with the auricle, and has a foliated appear- ance ; it is directed forwards towards the root of the pulmonary artery, to which the auriculae of both sides appear to converge. The left auricle is to be laid open by a -1- shaped incision, the horizontal section being made along the border, which is attached to the base of the ventricle. It presents for examination five openings, and the muscular structure of the appendix; these are— Four pulmonary veins, Auriculo-ventricular opening, Musculi pectinati. The Pulmonary vdns, two from the right and two from the left lung, open into the corresponding sides of the auricle. The two left pulmonary veins terminate frequently by a common opening. The auriculo-ventricular opening is the aperture of communication be- tween the auricle and ventricle. The Musculi pectinati are fewer in number than in the right auricle, and are situated only in the appendix auriculae. Left Ventricle. — The left ventricle is to be opened by making an incision a little to the left of the septum ventriculorum, and continuing it around the apex of the heart to the auriculo-ventricular opening behind. The left ventricle is conical, both in external figure and in the form of its internal cavity. It forms the apex of the heart, by projecting beyond the right ventricle, while the latter has the advantage in length towards the base. Its walls are about seven lines in thickness, those of the right ventricle being about two lines and a half. It presents for examination, in its interior, two openings, two valves, and the tendinous cords and muscular columns; they may be thus arranged: Auriculo-ventricular opening, Aortic opening. Mitral valves, Semilunar valves. Chordae tendineae, Columnae carneae. The Auriculo-ventricular opening is a dense fibrous ring, covered by the linino- membrane of the heart, but smaller in size than that of the right side. , , . . . , The Mitral valves are attached around the auriculo-ventricular opening, as are the tricuspid in the risrht ventricle. They are thicker than the tri- cuspid, and consist of only two segments, of which the larger is placed 482 STRUCTURE OF THE HEART. between the auriculo-ventricular opening and the commencement of the aorta, and acts the part of a valve to that foramen during the filling ofthe ventricle. The difference in size of the two valves, both being triangular, and the space between them, has given rise to the idea of a " bishop's Fig. 213.* mitre," after w7hich they were named. These valves, like the tricuspid, are furnished with an apparatus of tendinous cords, chorda tendinea, which are attached to two very large columna carnee. The Columna carnea admit of the same arrangement into three kinds, as on the right side. Those which are free by one extremity, the columnae papillares, are two in number, and larger than those on the opposite side; one being placed on the left wall of the ventricle, and the other at the junction of the septum ventriculorum with the posterior wall. The Semilunar valves are placed around the commencement of the aorta, like those of the pulmonary artery; they are similar in structure, and are attached to the scalloped border by which the aorta is connected with the ventricle. The tubercle in the centre of each fold is larger than those in the pulmonary valves, and it was these that Arantius particularly described; but the term " corpora Arantii" is now applied indiscrimi- nately to both. The fossae between the semilunar valves and the cylinder of the artery are larger than those of the pulmonary artery; they are called the "sinus aortid" (sinuses of Valsalva). structure of the heart. The arrangement of the fibres of the heart has been made the subject of careful investigation by Mr. Searle, to whose article, "Fibres ofthe Heart," * The anatomy of the heart; the organ is viewed on its left side. 1. The cavity of the left auricle. The number is placed on that portion of the septum auricularum cor- responding with the centre ofthe fossa ovalis. 2. The cavity of the appendix auriculae, near the apex of which are seen the musculi pectinati. 3. The opening of the two right pulmonary veins. 4. The sinus, into which the left pulmonary veins open. 5. The left pulmonary veins. 6. The auriculo-ventricular opening. 7. The coronary vein, lying in the auriculo-ventricular groove. 8. The left ventricle. 9, 9. The cavity of the left ventricle; the numbers rest on the septum ventriculorum. a. The mitral valve; its flaps are connected by chordas tendineae to 6, 6. The columnae carneae. c. c. Fixed columnae carneae, forming part of the internal surface of the ventricle, d. The arch of the aorta, from the summit of which the three arterial trunks ofthe head and upper ex- tremities are seen arising, e. The pulmonary artery. /. The obliterated ductus arte- FIBRES OF THE VENTRICLES. 483 in the Cyclopaedia of Anatomy and Physiology, I am indebted for the fol- lowing summary of their distribution :— For the sake of clearness of description the fibres of the ventricles have been divided mto three layers, superficial, middle, and internal, all of which are disposed in a spiral direction around the cavities of the ventri- cles. The mode of formation of these three layers will be best understood by adopting the plan pursued by Mr. Searle in tracing the course of the fibres from the centre of the heart towards its periphery. The left surface of the septum ventriculorum is formed by a broad and thick layer of fibres, which proceed backwards in a spiral direction around the posterior aspect of the left ventricle, and become augmented on the left side of that ventricle by other fibres derived from the bases of the two columnae papillares. The broad and thick band formed by the fibres from these two sources, curves around the apex and lower third of the left ven- tricle to the anterior border of the septum, where it divides into two bands, a short or apicial band, and a long or basial band. The Short or apicial band is increased in thickness at this point by re- ceiving a layer of fibres (derived from the root of the aorta and carneae columna') upon its internal surface, from the right surface of the septum ventriculorum; it is then continued onwards in a spiral direction from left to right, around the lower third of the anterior surface, and the middle third of the posterior surface of the right ventricle to the posterior border of the septum. From the latter point the short band is prolonged around the posterior and outer border of the left ventricle to the anterior surface ofthe base of that ventricle, and is inserted into the anterior border ofthe left auriculo-ventricular ring, and the anterior part of the root of the aorta and pulmonary artery. The Long or basial band, at the anterior border of the septum, passes directly backwards through the septum, (forming its middle layer,) to the posterior ventricular groove, where it becomes joined by fibres derived from the root of the pulmonary artery. It then winds spirally around the middle and upper third of the left ventricle to the anterior border of the septum, where it is connected by means of its internal surface with the superior fibres derived from the aorta, which form part of the right wall of the septum. From this point it is continued around the upper third of the anterior and posterior surface of the right ventricle to the posterior border of the septum, where it is connected with the fibres constituting the right surface of the septum ventriculorum. At the latter point the fibres of this band begin to be twisted upon themselves, like the strands of a rope, the direction of the twist being from below upwards. This arrangement of fibres is called by Mr. Searle " the rope ;" it is continued spirally upwards, forming the brim of the left ventricle, to the anterior surface of the base of that ventricle, where the twisting of the fibres ceases. The long band then curves inwards towards the septum, and spreads out upon the left surface of the septum into the broad and thick layer of fibres with which this description commenced. The most inferior of the fibres of the left surface of the septum ventri- culorum after winding spirally around the internal surface of the apex of the left ventricle so as to close its extremity, form a small fasciculus, riosus- the letter is placed in the cleft formed by the bifurcation of the pulmonary ar- tery, 'g. The left pulmonary arteiy. h. The right ventricle, i. The point of the appendix of the right auricle. 484 STRUCTURE OF THE HEART. which is excluded from the interior of the ventricle, and expands in a radiated manner over the surface of the heart, constituting its superficial layer of fibres. The direction of these fibres is, for the most part, oblique, passing from left to right on the anterior and from right to left on the pos- terior surface of the heart, becoming more longitudinal near its base, and terminating by being inserted into the fibrous rings of the auriculo-ventri- cular openings, and of the pulmonary artery and aorta. Over the right ventricle the superficial fibres are increased in number by the addition of accessory fibres from the right surface of the septum, which pierce the middle layer, and take the same direction with the superficial fibres from the apex of the left ventricle, and of other accessory fibres from the sur- face of both ventricles. From this description it will be perceived, that the superficial layer of fibres is very scanty, and is pretty equally distributed over the surface of both ventricles. The middle layer of both ventricles is formed by the two bands, short and long. But the internal layer of the two ventricles is very differently constituted: that of the left is formed by the spiral expansion of the fibres of the rope, and of the two columnae papillares; that of the right remains to be described. The septum ventriculorum also consists of three layers, a left layer, the radiated expansion of the rope and carneae columnae ; a middle layer, the long band; and a right layer, belonging to the proper wall of the right ventricle, and continuous both in front and behind with the long band, and in front also with the short band, and with the superficial layer ofthe right ventricle. The Internal layer of the right ventricle is formed by fasciculi of fibres which arise from the right segment of the root of the aorta, from the entire circumference of the root of the pulmonary artery, and from the bases of the columnae papillares. The fibres from the root ofthe aorta, associated with some from the carneae columnae, constitute a layer which passes ob- liquely forwards upon the right side of the septum. The superior fibres coming directly from the aorta join the internal surface of the long band at the anterior border of the septum, wiiile the lower two-thirds of the layer are continuous with the internal surface of the short band, some of its fibres piercing that band to augment the number of superficial fibres. The fibres derived from the root of the pulmonary artery, conjoined with those from the base of one of the columnae papillares, curve forwards from their origin, and wind obliquely downwards and backwards around the internal surface of the wall of the ventricle to the posterior border of the septum, where they become continuous with the long band, directly that it has passed backwards through the septum. Fibres ofthe Auricles. — The fibres of the auricles are disposed in two layers, external and internal. The internal layer is formed of fasciculi which arise from the fibrous rings of the auriculo-ventricular openings and proceed upwards to enlace with each other, and constitute the appendices auricularum. These fasciculi are parallel in their arrangement, and in the appendices form projections and give rise to the appearance which is de- nominated musculi pectinati. In their course they give off branches which connect adjoining fasciculi, and form a columnar interlacement between them. External Layer.—The fibres of the right auricle having completed the appendix, wind from left to right around the right border of this auricle, and along its anterior aspect, beneath the appendix, to the anterior surface ORGANS OF RESPIRATION AND VOICE. 485 of the septum. From the septum they are continued to the anterior sur- face of the left auricle, where they separate into three bands, superior, an- terior, and posterior. The superior band proceeds onwards to the appen- dix, and encircles the apex of the auricle. The anterior band passes to the left, beneath the appendix, and winds as a broad layer completely around the base of the auricle, and through the septum to the root of the aorta, to which it is partly attached, and from this point is continued on- wards to the appendix, where its fibres terminate by interlacing with the musculi pectinati. The posterior band, crosses the left auricle obliquely to its posterior part, and winds from left to right around its base, encircling the openings of the pulmonary veins ; some of its fibres are lost on the surface of the auricle, others are continued onwards to the base of the aorta; and a third set, forming a small band, are prolonged along the anterior edge of the appendix to its apex, where they are continuous with the superior band. The septum auricularum has four sets of fibres enter- ing into its formation ; 1. The fibres arising from the auriculo-ventricular rings at each side ; 2. Fibres arising from the root of the aorta, which pass upwards to the transverse band, and to the root of the superior cava; 3. Those fibres of the anterior band that pass through the lower part of the septum in their course around the left auricle ; and, 4. A slender fascicu- lus, which crosses through the septum from the posterior part of the right auriculo-ventricular ring to the left auricle. It will be remarked, from this description, that the left auricle is consi- derably thicker and more muscular than the right. Vessels and Nerves.—The Arteries supplying the heart are the anterior and posterior coronary. The Veins accompany the arteries, and empty themselves by the common coronary vein into the right auricle. The lymphatics terminate in the glands about the root of the heart. The nerves of the heart are derived from the cardiac plexuses, which are formed by -.ommunicating filaments from the sympathetic and pneumogastric. ORGANS OF RESPIRATION AND VOICE. The organs of respiration are the two lungs, with their air-tube, the trachea, to the upper part of which is adapted an apparatus of cartilages, constituting the organ of voice, or larynx. the larynx. The Larynx is situated at the fore part of the neck, between the trachea and the base of the tongue. It is a short tube, having an hour-glass form, and is composed of cartilages, ligaments, muscles, vessels, nerves, and mucous membrane. The Cartilages are the— Thyroid, Two cuneiform, Cricoid, Epiglottis. Two arytenoid, The Thyroid (Svnk—^og, like a shield) is the largest cartilage of the larynx : it consists of two lateral portions, or ala, which meet at an angle in front and form the projection which is known by the name of pomum Adami! In the male, after puberty, the angle of union of the two alae is 41* 486 CARTILAGES OF THE LARYNX. acute; in the female, and before puberty in the male, it is obtuse. "Where the pomum Adami is prominent, a bursa mucosa is often found between it and the skin. Each ala is quadrilateral in shape, and forms a rounded border poste- riorly, winch terminates above, in the superior cornu, and below, in the inferior cornu. Upon the side of the ala is an oblique line, or ridge, di- rected downwards and forwards, and bounded at each extremity by a tubercle. Into this line the sterno-thyroid muscle is inserted ; and from it the thyro-hyoid and inferior constrictor take their origin. In the receding angle, formed by the meeting of the two alae upon the inner side of the cartilage, and near its lower border, are attached the epiglottis, the chordae vocales, the thyro-arytenoid, and thyro-epiglottidean muscles. The Cricoid (xgi'xog—eT<5os, like a ring) is a ring of cartilage, narrow in front, and broad behind, where it is surmounted by two rounded surfaces, which articulate with the arytenoid cartilages. At the middle line, poste- riorly, is a vertical ridge which gives attachment to the oesophagus, and on each side of the ridge are the depressions which lodge the crico-aryte- noidei postici muscles. On either side of the ring is a glenoid cavity, which articulates with the inferior cornu of the thyroid cartilage. The Arytenoid cartilages (dgwraiva,* a pitcher), two in number, are tri- angular and prismoid in form. They are broad and thick below where they articulate with the upper border of the cricoid cartilage; pointed above, and prolonged by twro small pyriform cartilages, cornicula laryngis (capitula Santorini), which are curved inwards and backwards, and they each present three surfaces, anterior, posterior, and internal. The poste- rior surface is concave, and lodges part of the arytenoideus muscle; the internal surface is smooth, and forms part of the lateral wall of the larynx; the anterior or external surface is rough and irregular, and gives attach- ment to the chorda vocalis, thyro-arytenoideus, crico-arytenoideus lateralis and posticus, and, above these, to the base of the cuneiform cartilage. The Cunriform cartilages are two small cylinders of fibro-cartilage, about seven lines in length, and enlarged at each extremity. By the lower end, or base, the cartilage is attached to the middle ofthe external surface of the arytenoid, and by its upper extremity forms a prominence in the border of the aryteno-epiglottidean fold of membrane. They are some- times wanting. In the male, the cartilages of the larynx are more or less ossified, par- ticularly in old age. The Epiglottis (swiyAwa, near, ofo, wro?, the ear,) the largest of the three, is situated immediately in front of the external ear, and extends superficially for a short distance over the masseter muscle, and deeply be- hind the ramus of the lower jaw. It reaches inferiorly to below- the level of the angle of the lower jaw, and posteriorly to the mastoid process, slightly overlapping the insertion of the sterno-mastoid muscle. Embedded in its substance are the external carotid artery, temporo-maxillary vein, and facial nerve ; emerging from its anterior border, the transverse facial artery and branches of the pes anserinus; and above, the temporal artery. The duct of the parotid gland (Stenon's* duct) commences at the pa- pilla upon the internal surface of the cheek, opposite the second molar tooth of the upper jaw ; and, piercing the buccinator muscle, crosses the masseter to the anterior border of the gland, where it divides into several branches, which subdivide and ramify through its structure, to terminate in the small caecal pouches of which the gland is composed. A small branch is generally given off from the duct while crossing the masseter muscle, which forms, by its ramifications and terminal dilatations, a small glandular appendage, the soda parotidis. Stenon's duct is remarkably dense and of considerable thickness, while the area of its canal is extremely small. , . , • i /. i i The Submaxillary gland is situated in the posterior angle of the sub- * Nicholas Stenon, an anatomist of great research. He discovered the parotid duct while in Paris He was appointed Professor of Medicine in Copenhagen in 1672. His work " De Musculis et Glandulis Observationes," was published in 1664. 504 PHARYNX. maxillary triangle of the neck. It rests upon the hyo-glossus and mylo- hyoideus muscles, and is covered in by the body ofthe lower jaw and by the deep cervical fascia. It is separated from the parotid gland by the stylo-maxillary ligament, and from the sublingual by the mylo-hyoideus muscle. Embedded among its lobules are the facial artery and submax- illary ganglion. The excretory duct (Wharton's) of the submaxillary gland commences upon the papilla, by the side ofthe fraenum linguae, and passes backwards beneath the mylo-hyoideus and resting upon the hyo-glossus muscle, to the middle of the gland, where it divides into numerous branches, which ramify through the structure of the gland, and terminate by csecal extremi- ties. It lies in its course against the mucous membrane forming the floor of the mouth, and causes a prominence of that membrane. The Sublingual is an elongated and flattened gland, situated beneath the mucous membrane of the floor of the mouth, on each side of the frae- num linguae. It is in relation, above, with the mucous membrane; in front, with the depression by the side of the symphysis ofthe lower jaw; externally, with the mylo-hyoideus muscle ; and, internally, with the hy- poglossal nerve and genio-hyo-glossus muode. It pours its secretion into the mouth by seven or eight small ducts, which open by small apertures on each side of the fraenum linguae. Structure.—The salivary are conglomerate glands, consisting of lobes, which are made up of polyhedral lobules, and these of smaller lobules. The smallest lobule is apparently composed of granules, which are mi- nute csecal pouches, formed by the dilatation of the extreme ramifications of the ducts. These minute ducts unite to form lobular ducts, and the lobular ducts constitute by their union a single excretory duct. The caecal pouches are connected by areolo-fibrous tissue, so as to form a minute lobule ; the lobules are held together by a more condensed areolar layer; and the larger lobes are enveloped by a dense areolo-fibrous capsule, w7hich is firmly attached to the deep cervical fascia. Vessels and Nerves.—The parotid gland is abundantly supplied with arteries by the external carotid; the submaxillary by the facial; and the sublingual by the sublingual branch of the lingual artery. The Nerves of the parotid gland are derived from the auricular branch of the inferior maxillary, from the auricularis magnus, and from the nervi molles accompanying the external carotid artery. The submaxillary gland is supplied by the branches of the submaxillary ganglion, and by filaments from ihe mylo-hyoidean nerve ; and the sublingual by filaments from the submaxillary ganglion and gustatory nerve. PHARYNX. The pharynx ( *» * ,obes 17. The notch on the posterior 44 518 LOBES OF THE LIVER. 'his point, the portal vein. At their entrance into the transverse'fissure the branches of the hepatic duct are the most anterior, next those of the artery, and most posteriorly the portal vein. The Fissure for the gall-bladder is a shallow fossa extending forwards, parallel with the longitudinal fissure, from the right extremity of the trans- verse fissure to the free border of the liver, where it frequently forms ; notch. The Fissure for the vena cava is a deep and short fissure, occasion. a circular tunnel, which proceeds from a little behind the right extremu of the transverse fissure to the posterior border of the liver, and lodges the inferior vena cava. These five fissures taken collectively resemble an inverted y, the base corresponding with the free margin of the liver, and the apex with its pos- terior border. Viewing them in this way, the two anterior branches re- present the longitudinal fissure on the left, and the fissure for the gall- bladder on the right side ; the two posterior, the fissure for the ductus venosus on the left, and the fissure for the vena cava on the right side; and the connecting bar, the transverse fissure. Lobes.—The Right lobe is four or six times larger than the left, from which it is separated, on the concave surface, by the longitudinal fissure, and, on the convex, by the longitudinal ligament. It is marked upon its under -irface by the transverse fissure, and by the fissures for the gall- b^dd- and vena cava; and presents three depressions, one, in front, for t cui(- f of the ascending colon, and two, behind, for the right supra- r- al c \k ale and kidrey. '°he Left lobe is small ->d flattened, convex upon its upper surface, and concave below, where it iies in contact with the anterior surface of th stomach. It is sometimes in contact by its extremity with the upper of the spleen, and is in relation, by its posterior border, with the cardiaj orifice of the stomach and left pneumogastric nerve. The Lobus quadratus is a quadrilateral lobe situated on the under sur- face of the right lobe ; it is bounded, in front, by the free border of the liver; behind, by the transverse fissure ; to the right, by the gall-bladder; and to the left, by the longitudinal fissure. The Lobus Spigelii* is a small triangular lobe, also situated on the under surface of the right lobe : it is bounded, in front, by the transverse fissure ; and, on the sides, by the fissures for the ductus venosus and vena cava. The Lobus caudatus is a small tail-like appendage of the lobus Spigelii, from which it runs outwards like a crest into the right lobe, and serves to s; parate the right extremity of the transverse fissure from the commence- ment of the fissure for the vena cava. In some persons this lobe is well marked, in others it is small and ill-defined. Reverting to the comparison of the fissures with an inverted y, it will be observed, that the quadrilateral interval, in front of the transverse bar, represents the lobus quadratus; the triangular space behind the bar, the lobus Spigelii; and the apex of the letter, the point of union between the inferior vena cava and the remains of the ductus venosus. Vessels and Nerves.—The vessels entering into the structure of the liver are a\so five in number; they are the * Adrian Spigel, a Belgian physician, professor at Padua after Casserius in 1616. He assigned considerable importance to this little lobe, but it had been described by Syl- vius full sixty years before his time. STRUCTURAL ANATOMY OF THE LIVER. 519 Hepatic artery, Hepatic ducts, Portal vein. Lymphatics. Hepatic veins, ' The Hepatic artery, portal vdn, and hepatic duct enter the liver at the transverse fissure, and ramify through portal canals to every part of the - rgan; so that their general direction is from below upwards, and from centre towards the circumference. The Hepatic veins commence at the circumference, and proceed from •j'efore backwards, to open into the vena cava, on the posterior border of the liver. Hence the branches of the two veins cross each other in their course. The portal vein, hepatic artery, and hepatic duct are moreover enve- loped in a loose areolar tissue, the capsule of Glisson, which permits them to contract upon themselves when emptied of their contents ; the hepatic veins, on the contrary, are closely adherent by their parietes to the surface of the canals in which they run, and are unable to contract. By these characters the anatomist is enabled, in any section of the liver, to distin- guish at once the most minute branch of the portal vein from an hepatic vein: the former will be found more or less collapsed, and always accom- panied by an artery and duct, and the latter widely open and solitary. The Lymphatics of the liver are described in the Chapter dedicated to those vessels. '": The Nerves of the liver are derived from the systems both c.1'.ini»,:al a>acked together, and surrounded by an epithelium which is conti- nuous with a similar structure lining the inner surface of the capsule. They are derived from a small artery, w7hich, after piercing the capsule, immediately divides in a radiated manner into several branches. From the interior of this little vascular ball a vein proceeds, smaller than the corresponding artery, and pierces the capsule close by the artery, to com- municate with the efferent vessels of other Malpighian bodies and consti- tute a venous plexus. The cones or mamillary processes of the interior of the kidney are in- vested by mucous membrane, which is continuous at their apices with the uriniferous tubuli, and is reflected from their sides so as to form around each a cup-like pouch, or calyx. The calices communicate with a com- mon cavity of larger size, situated at each extremity, and in the middle of the organ ; and these three cavities, the infundibula, constitute by their union the large membranous sac, which occupies the hdus renalis, the pelvis of the kidney. The kidney in the embryo and foetus consists of lobules. See the ana- tomy ofthe foetus in the succeeding Chapter. The Ureter, (oSfov, urine, rr^siv, to keep,) the excretory duct of the kid- ney, is a membranous tube of about the diameter of a goose-quill, and nearly eighteen inches in length; it is continuous superiorly with the pel- vis of.the kidney, and is constricted inferiorly, where it lies in an oblique direction between the muscular and mucous coats ofthe base ofthe blad- der, and opens upon its mucous surface. Lying along the posterior wall of the abdomen, it is situated behind the peritoneum, and is crossed by the spermatic vessels ; in its course downwards it rests against the anterior surface of the psoas, and crosses the common iliac artery and vein, and then the external iliac vessels. Within the pelvis it crosses the umbilical artery and the vas deferens in the male, and the upper part of the vagina in the female. There are sometimes two ureters to one kidney. The ureter, the pelvis, the infundibula, and the calices are composed of two coats, an external or fibrous coat, the tunica propria; and an internal mucous coat, which is continuous with the mucous membrane of the * On the intimate Structure of the Human Kidney, &c. Medico-Chirurgical Trans- actions, vol. xxix., 1846. PORTAL CIRCULATION OF THE KIDNEYS. 531 Fig. 233.* bladder inferiorly, and with that of the tubuli uriniferi above. Vessels and Nerves.—The renal artery is derived from the aorta ; it divides into several large branches before entering the hilus, and within the organ ra- mifies in an arborescent manner, terminating in nutrient twigs, and in the small inferent vessels of the corpora Malpighiana. In the Malpighian bodies the inferent vessels divide into several pri- mary twigs, which subdivide into capillaries, and the capillaries, after forming loops, converge to the efferent vein, which is generally smaller than the corresponding artery. The efferent veins proceed to and form a capillary venous plexus, which surrounds the tortuous tubuli uriniferi, and from this venous plexus the blood is conveyed, by converg- ing branches, into the renal vein. "Thus," remarks Mr. Bowman, "there are in the kidney two perfectly distinct systems of capillary vessels, through both of which the blood passes in its course from the arteries into the veins: the first, that" which forms the vascular tuft in the Malpighian bodies, and is " in immediate connexion with the arteries; the second, that enveloping the convolutions of the tubes and communicating directly with the veins. The efferent vessels of the Malpighian bodies, that carry the blood between these two systems, may collectively be termed the portal system of the kidney." The inferences draw7n by Mr. Bowman from his investigations are interest- ing ; they are, that the capillary tufts of the Malpighian bodies are the part of the kidney specially acted on by diuretics ; that they are the medium by which water, certain salts, and other substances, pass out of the system; that they are, moreover, the means of escape of certain morbid products, such as sugar, albumen, and the red particles of the blood. Respecting the capillary venous plexus, we have proof that the principal proximate constituents of urine, such as urea, lithic acid, &c, are, like the bile, de- rived from venous (portal) blood. The Veins of the kidney commence at the surface by minute converging venules, the stellated vessels, and proceed inwards, receiving in their course the veins of the cortical and tubular portions of the organ. On arriving at the pelvis, they unite to form the branches of the renal vein, which terminates in the vena cava by a single large trunk on each side ; the left renal vein receiving the left spermatic vein. Injections thrown into the renal artery, and returning by the tubuli uriniferi, make their way into those tubes by rupture. The lymphatic vessels terminate in the lum- bar glands. . The Nerves are derived from the renal plexus, which is formed partly by the solar plexus, and partly by the lesser splanchnic nerve. ^ The renal plexus gives branches to the spermatic plexus, and branches which accom- * Plan of the renal circulation; copied from Mr. Bowman's paper, a. A branch of the renal artery giving off several Malpighian twigs. 1. An efferent twig to the capil- lary tuft contained in "the Malpighian body, m; from the Malpighian body the urinife- rous tube is seen taking its tortuous course to r. 2, 2. Efferent veins ; that which pro- ceeds from the Malpighian body is seen to be smaller than the corresponding artery. The capillary venous plexus, ramifying upon the uriniferous tube. This plexus receives its blood from the efferent veins, 2, 2, and transmits it to the branch of the renal vein, v. 532 PELVIS--BLADDER. any the ureters: hence the morbid sympathies which exist between the idney, the ureter, and the testicle: and by the communications with the solar plexus, with the stomach and diaphragm, and indeed with the whole system. In the intimate structure of the kidney, the nerve-fibres are, ac- cording to Mr. Toynbee, continuous with the nucleated cells of the paren- chyma of that organ. PELVIS. The cavity of the pelvis is that portion of the great abdominal cavity which is included within the bones of the pelvis, below the level of the linea-ilio-pectinea and the promontory of the sacrum. It is bounded by the cavity of the abdomen above, and by the perineum below7; its internal parietes are formed, in front, below, and at the sides, by the peritoneum, pelvic fascia, levatores ani muscles, obturator fasciae, and muscles; and behind, by the sacrum and sacral plexus of nerves. The Viscera of the pelvis in the male are, the urinary bladder, the pros- tate gland, vesiculae seminales, and the rectum. BLADDER. The Bladder is an oblong membranous viscus of an ovoid shape, situated behind the ossa pubis and in front of the rectum. It is larger in its ver- tical diameter than from side to side; and its long axis is directed from above, obliquely downwards and backwards. It is divided into, body, fundus, base, and neck. The body comprehends the middle zone of the organ; the fundus, its upper segment; the base, the lower broad extre- mity which rests on the rectum; and the neck, the narrow constricted por- tion which is applied against the prostate gland. This organ is retained in its place by ligaments, winch are divided into true and false ; the true ligaments are seven in number, two anterior, two lateral, two umbilical, and the urachus; the false ligaments are folds of the peritoneum, and are four in number, tw7o anterior and two posterior. The anterior ligaments are formed by the pelvic fascia, which passes from the inner surface of the os pubis, on each side of the symphysis, to the front of the bladder. The lateral ligaments are formed by the reflexion of the pelvic fascia from the levatores ani muscles, upon the sides of the base of the bladder. The umbilical ligaments are the fibrous cords which result from the obliteration of the umbilical arteries of the foetus; they pass forwards on each side of the fundus of the bladder, and ascend beneath the peritoneum to the umbilicus. The urachus is a small fibrous cord formed by the obliteration of a tubular canal existing in the embryo : it is attached to the apex of the bladder, and thence ascends to the umbilicus. The false ligaments are folds of peritoneum ; the two lateral correspond with the passage of the vasa deferentia from the sides of the bladder to the internal abdominal rings, and the two posterior with the course of the umbilical arteries, to the fundus of the organ. The bladder is composed of three coats, an external or serous coat, a muscular, and a mucous coat. The serous coat is partial, and derived from the peritoneum, which invests the posterior surface and sides of the bladder, from about opposite the point of termination of the two ureters URINARY BLADDER. 533 to its summit, whence it is guided to the anterior wall of the abdomen by the umbilical ligaments and urachus. The muscular coat consists of two Fig. 234.» layers, an external layer composed of longitudinal fibres, the detrusor urinie; and an internal layer of oblique and transverse fibres irregularly distributed. The anterior longitudinal fibres commence by four tendons (the tendons of the bladder or of the detrusor urinae), two superior from the ossa pubis, and two inferior from the rami of the ischia, and spread out as they ascend upon the anterior surface of the bladder to its fundus; they then converge upon the posterior surface of the organ, and descend to its neck, where they are inserted into the isthmus of the prostate gland, and into a ring of muscular tissue, which surrounds the commencement of the prostatic portion of the urethra. Some of the anterior fibres are also attached to this ring. The lateral fibres commence at the prostate gland and the muscular ring of the urethra on one side, and spread out as they ascend upon the side of the bladder to descend upon the opposite side, and be inserted into the prostate and opposite segment of the same ring. Two bands of oblique fibres are described by Sir Charles Bell, as * A side view ofthe viscera ofthe male pelvis, in situ. The right side ofthe pelvis has been removed by a vertical section made through the os pubis near the symphysis; and another through the middle ofthe sacrum. 1. The divided surface ofthe os pubis. 2. The divided surface ofthe sacrum. 3. The body ofthe bladder. 4. Its fundus; from the apex is seen passing upwards the urachus. 5. The base of the bladder. 6. The ureter. 7. The neck of the bladder. 8, 8. The pelvic fascia; the fibres immediately above 7 are given off from the pelvic fascia, and represent the anterior ligaments ofthe bladder. 9. The prostate gland. 10. The membranous portion ofthe urethra, between the two layers ofthe deep perineal fascia. 11. The deep perineal fascia formed of two layers. 12. One of Cowper's glands between the two layers of deep perineal fascia, and beneath the membranous portion of the urethra. 13. The bulb of the corpus spongiosum. 14. The body ofthe corpus spongiosum. 15. The right crus penis. 16. The upper part of the first portion of the rectum. 17. The recto-vesical fold of peritoneum. 18. The second portion ofthe rectum. 19. The right vesicula seminalis. 20. The vas deferens. 21. The rectum covered by the descending layer of the pelvic fascia, just as it is making its bend backwards to constitute the third portion. 22. A part of the levator ani muscle investing the lower part of the rectum. 23. The external sphincter ani. 24. The in- terval between the deep and superficial perineal fascia: they are seen to be continuous beneath the number. 45* 534 PROSTATE GLAND. originating at the terminations of the ureters, and converging to the neck of the bladder: the existence of these muscles is not well established The fibres corresponding with the trigonum vesica? are transverse. It has been shown by Mr. Guthrie,* that there are no fibres at the neck of the bladder capable of forming a sphincter vesicae ; but Mr. Lanef has described a fasciculus of muscular fibres which surround the commence- ment of the urethra, and perform such an office. These fibres form a narrow bundle above the urethra, but spread out below7 behind the prostate gland: they are brought into view by dissecting off the mucous mem- brane from around the orifice of the urethra. Sir Astley Cooper has described around the urethra, within the prostate gland, a ring of elastic tissue, Or, rather, according to Mr. Lane, of mus- cular fibres, which has for its object the closure of the urethra against the involuntary passage of the urine. It is into this ring that the longitudinal fibres of the detrusor urinae are inserted, so that the muscle, taking a fixed point at the os pubis, will not only compress the bladder, and thereby tend to force its contents along the urethra, but will at the same time, by means of its attachment to the ring, dilate the entrance of the urethra, and afford a free egress to the contents of the bladder. The Mucous coat is thin and smooth, and exactly moulded upon the muscular coat, to which it is connected by a somewhat thick layer of sub- mucous tissue, called by some anatomists the nervous coat; its papillae are very minute, and there is scarcely a trace of mucous follicles. This mucous membrane is continuous, through the ureters, with the lining membrane ofthe uriniferous ducts, and, through the urethra, with that of the prostatic ducts, tubuli seminiferi, and Cowper's glands. Upon the internal surface of the base of the bladder is a triangular smooth plane of a paler colour than the rest ofthe mucous membrane, the trigonum vesicae, or trigone vesicate, (fig. 237.) This is the most sensi- tive part of the bladder, and the pressure of calculi upon it gives rise to great suffering. It is bounded on each side by the raised ridge, corre- sponding with the muscles of the ureters, at each posterior angle by the openings of the ureters, and, in front, by a slight elevation of the mucous membrane at the entrance of the urethra, called uvula vesica. The external surface of the base of the bladder corresponding with the trigonum, is also triangular, and is separated from the rectum merely by a thin layer of fibrous membrane, the recto-vesical fascia. It is bounded behind by the recto-vesical fold of peritoneum ; and on each side by the vas deferens and vesicula seminalis, which converge almost to a point at the base of the prostate gland. It is through this space that the opening is made in the recto-vesical operation for puncture of the bladder. PROSTATE GLAND. The prostate gland (t^oIo'ttjiuii praeponere) is situated in front of the neck of the bladder, behind the deep perineal fascia, and upon the rectum, through which latter it may be felt with the finger. It surrounds the com- mencement of the urethra for a little more than an inch of its extent, and resembles a Spanish chestnut both in size and form; the base being directed backwards tow7ards the neck of the bladder, the apex forwards, * " On the Anatomy and Diseases of the Neck of the Bladder and of the Urethra." f Lancet, vol i. 1842-43, p. 670. VESICULAE SEMINALES. 535 and the convex side towards the rectum. It is retained firmly in its posi- tion by the two superior and two inferior tendons of the bladder, by the attachments of the pelvic fascia, and by a process of the internal layer of the deep perineal fascia, which forms a sheath around the membranous urethra, and is inserted into the apex of the gland. It consists of three lobes, two lateral and a middle lobe or isthmus; the lateral lobes are distinguished by an indentation upon the base ofthe gland, and by a slight furrow upon its upper and lower surface. The third lobe or isthmus is a small transverse band which passes between the two lateral lobes at the base of the organ. In structure the prostate gland is composed of ramified ducts, terminating in lobules of follicular pouches, which are so closely compressed as to give to a thin section ofthe gland a cellular appearance. It is pale in colour and hard in texture, splits easily in the course of its ducts, and is surrounded by a plexus of veins which are enclosed by the strong fibrous membrane with which it is invested. Its secretion is poured into the prostatic portion of the urethra by fifteen or twenty excretory ducts. The urethra in passing through the prostate lies one-third nearer its upper than its lower surface. VESICULJE SEMINALES. On the under surface of the base of the bladder, and converging towards the base ofthe prostate gland, are tw7o lobulated and somewhat pyriform bodies, about two inches in length, the vesiculae seminales. Their upper surface is in contact with the base of the bladder; the under side rests on the rectum, separated only by the recto-vesical fascia; the larger extremities are directed back- wards and outwards, and the smaller ends almost meet at the base of the prostate. They enclose between them a triangular space, which is bounded posteriorly by the recto-vesical fold of peritoneum, and which corresponds with the trigonum vesicae on the interior of the bladder. Each vesicula is formed by the convolutions of a single tube, wilich gives off several irregular ,| caecal branches. It is enclosed in a dense |; fibrous membrane, derived from the pelvic \'. fascia, and is constricted beneath the isthmus V of the prostate gland into a small excretory duct. The vas deferens, somewhat enlarged and convoluted, lies along the inner border of each vesicula, and is included in its fibrous in- vestment. It communicates with the duct of the vesicula, beneath the isthmus of the prostate, and formsf the ejaculatory duct. The ejacula- * The posterior aspect of the male bladder ; the serous covering is removed in order to show the muscular coat. 1. The body ofthe bladder. 2. Its fundus. 3. Its inferior fundus or base. 4. The urachus. 5, 5. The ureters. 6, 6. The vasa deferentia. 7, 7. The vesiculae seminales. The triangular area, bounded by the vasa deferentia and vesiculae seminales on either side, a dotted line above and the numeral 3 below, is the space corresponding with the trigonum vesicae. It is this part of the bladder which is pierced, in puncturing the bladder through the rectum. The dotted line, forming the base of this triangular area, marks the extent of the recto-vesical fold ofthe peritoneum. f It.has been customary hitherto, in works on anatomy, to describe the course of ex- cretory ducts as proceeding from the gland, and passing thence to the point at which 536 MALE ORGANS OF GENERATION--PENIS. tory duct is about three quarters of an inch in length, and running for- wards, first between the base of the prostate and the isthmus, and then through the tissue of the veru montanum, opens upon the mucous mem- brane of the urethra, near its fellow of the opposite side, at the anterior extremity of that process. MALE ORGANS OF GENERATION. The organs of generation in the male are, the penis and the testes, with their appendages. PENIS. The Penis is divisible into a body, root, and extremity. The body is surrounded by a thin integument, which is remarkable for the looseness of its areolar connexion with the deeper parts of the organ, and for con- taining no adipose tissue. The root is broad, and firmly adherent to the rami of the ossa pubis and ischia by means of two strong processes, the crura, and is connected to the symphysis pubis by a fibrous membrane, the ligamentum suspensorium. The extremity, or glans penis, resembles an obtuse cone, somewhat compressed from above downw7ards, and of a deeper red colour than the surrounding skin. At its apex is a small ver- tical slit, the meatus urinarius, which is bounded by tw7o, more or less protuberant, labia; and, extending backwards from the meatus, is a de- pressed raphe, to which is attached a loose fold of mucous membrane, the fraenum praeputii. The base ofthe glans is marked by a projecting collar, the corona glandis, upon which are seen a number of small papillary ele- vations, the glandulae Tysoni (odoriferae). Behind the corona is a deep fossa, bounded by a circular fold of integument, the praputium, which, in the quiescent state of the organ, may be drawn over the glans, but, in its distended state, is obliterated, and serves to facilitate its enlargement. The internal surface of the prepuce is lined by mucous membrane, covered by a thin epithelium ; this membrane, on reaching the base of the glans, is reflected over the glans penis, and, at the meatus urinarius, is continuous with the mucous lining of the urethra. The penis is composed of the corpus cavernosum and corpus spongio- sum, and contains in its interior the longest portion of the urethra. The Corpus cavernosum is distinguished into two lateral portions (cor- pora cavernosa) by an imperfect septum and by a superior and inferior groove, and is divided posteriorly into two crura. It is firmly adherent, by means of its crura, to the rami of the ossa pubis and ischia. It forms, anteriorly, a single rounded extremity, which is received into a fossa in the base of the glans penis; the superior groove lodges the dorsal vessels of the organ, and the inferior receives the corpus spongiosum. Its fibrous tunic is thick, elastic, and extremely firm, and sends a number of fibrous bands and cords (trabeculae) inwards from its inferior groove, which cross its interior in a radiating direction, and are inserted into the inner walls of the tunic. These trabeculae are most abundant on the middle line, where the secretion is poured out. In the description of the vas deferens, with its connexion with the duct of the vesicula seminalis, I have adopted this plan, that I might not too far depart from established habit. But as it is more correct and consistent with the present state of science to consider the gland as a development ofthe duct, I have pur- sued the latter principle in the description of most of the other glandular organs of the body. ERECTILE TISSUE—URETHRA. 537 they are ranged vertically, side by side, somewhat like the teeth of a comb, and constitute the imperfect partition of the corpus cavernosum, called septum pectmiforme. This septum is more complete at its posterior than towards its anterior part. The tunic of the corpus cavernosum consists of strong longitudinal fibrous fasciculi, closely interwoven with each other. Its internal structure is composed of erectile tissue. The Corpus spongiosum is situated along the under surface of the corpus cavernosum, in its inferior groove. It commences by its posterior extre- mity between and beneath the crura penis, where it forms a considerable enlargement, the bulb, and terminates anteriorly by another expansion, the glans penis. Its middle portion, or body, is nearly cylindrical, and tapers gradually from its posterior towards its anterior extremity. The bulb is adherent to the deep perineal fascia by means of the tubular prolongation of the anterior layer, which surrounds the membranous portion of the urethra; in the rest of its extent the corpus spongiosum is attached to the corpus cavernosum by areolar tissue, and by veins which wind around that body to reach the dorsal vein. It is composed of erectile tissue, en- closed by a dense fibrous layer, much thinner than that of the corpus cavernosum, and contains in its interior the spongy portion ofthe urethra, which lies nearer its upper than its lower wall. Erectile tissue is a peculiar cellulo-vascular structure, entering in con- siderable proportion into the composition of the organs of generation. It consists essentially of a plexus of veins so closely convoluted and inter- woven with each other, as to give rise to a cellular appearance when ex- amined by means of a section. The veins forming this plexus are smaller in the glans penis, corpus spongiosum, and circumference of the corpus ravernosum, than in the central part of the latter, wiiere they are large and dilated. They have no other coat than the internal lining prolonged from the neighbouring veins ; and the interstices of the plexus are occupied by a peculiar reddish fibrous tissue. They receive their blood from the ca- pillaries of the arteries in the same manner with veins generally, and not by means of vessels having a peculiar form and distribution, as described by Miiller. The helicine arteries of that physiologist have no existence. Vessels and Nerves.—The arteries of the penis are derived from the in- ternal pudic ; they are, the arteries of the bulb, arteries of the corpus cavernosum, and dorsales penis. Its vdns are superficial and deep. The deep veins run by the side of the deep arteries, and terminate in the in- ternal pudic veins. The superficial veins escape in considerable number from the base of the glans, and converge on the dorsum penis, to form a large dorsal vein, which receives other veins from the corpus cavernosum and spongiosum in its course, and passes backwards between two layers of the ligamentum suspensorium, and through the deep fascia beneath the arch of the os pubis, to terminate in the prostatic and vesical plexuses. The Lymphatics terminate in the inguinal glands. The Nerves are de- rived from the internal pudic nerve, from the sacral plexus, and, as shown by Professor Miiller, in his beautiful monograph, from the hypogastric plexus. URETHRA. The urethra is the membranous canal extending from the neck of the bladder to the meatus urinarius. It is curved in its course, and is com- 538 URETHRA. posed of two layers, a mucous coat and an elastic fibrous coat. The mu- cous coat is thin and smooth ; it is continuous, internally, with the mucous membrane of the bladder; externally, with the investing membrane of the glans ; and at certain points of its extent, with the lining membrane ofthe numerous ducts which open into the urethra, namely, those of Cowper's Fig. 236* glands, the prostate gland, vasa deferentia, and vesiculae seminales. The elastic fibrous coat varies in thickness in the different parts of the course of the urethra: it is thick in the prostate gland, forms a firm investment for the membranous portion ofthe canal, and is thin in the spongy portion, w7here it serves as a bond of connexion between the mucous membrane and the corpus spongiosum. The urethra is about nine inches in length, and is divided into a prostatic, membranous, and spongy portion. The Prostatic portion, a little more than an inch in length, is situated in the prostate gland, about one-third nearer its upper than its lower surface, and extending from its base to its apex. Upon its lower circum- * A longitudinal section ofthe bladder, prostate gland, and penis, showing the urethra. 1. The urachus attached to the upper part of the fundus of the bladder. 2. The recto- vesical fold of peritoneum, at its point of reflexion from the base of the bladder, upon the anterior surface of the rectum. 3. The opening of the right ureter. 4. A slight ridge, formed by the muscle of the ureter, and extending from the termination of the ureter to the commencement of the urethra. This ridge forms the lateral boundary of the trigonum vesicae. 5. The commencement of the urethra; the elevation of mucous membrane immediately below the number is the uvula vesicae. The constriction ofthe bladder at this point is the neck ofthe bladder. 6. The prostatic portion ofthe urethra. 7. The prostate gland; the difference of thickness of the gland, above and below the urethra, is shown. 8. The isthmus, or third lobe of the prostate; immediately beneath which the ejaculatory duct is seen passing. 9. The right vesicula seminalis ; the vas deferens is seen to be cut short off, close to its junction with the ejaculatory duct. 10. The membranous portion ofthe urethra. 11. Cowper's gland ofthe right side, with its duct. 12. The bulbous portion ofthe urethra; throughout the whole length of the ure- thra of the corpus spongiosum, numerous lacunae are seen. 13. The fossa navicularis. 14. The corpus cavernosum, cut somewhat obliquely to the right side, near its lower part. The character of the venous cellular texture is well shown. 15. The right crus penis. 16. Near the upper part ofthe corpus cavernosum, the section has fallen a little to the left of the middle line ; a portion of the septum pectiniforme is consequently seen. This figure also indicates the thickness of the fibrous investment of the corpus cavernosum, and its abrupt termination at the base of (17) the glans penis. 8 The lower segment of the glans. 19. The meatus urinarius. 20. The corpus spongiosum. 2i. Ihe bulb of the corpus spongiosum. URETHRA. 539 ference or floor is a longitudinal fold of mucous Fig. 237* membrane, the veru montanum, or caput gallina- ginis, and on each side of the veru, a depressed fossa, the prostatic sinus, in which are seen the numerous openings of the prostatic ducts. At the anterior extremity of the veru montanum are the openings of the two ejaculatory ducts, and between them a third opening, which leads backwards into a small caecal sac, the sinus pocularis. The pros- tatic portion of the urethra, when distended, is the most dilated part of the canal; but, excepting dur- ing the passage of urine, is completely closed by means of a ring of muscular tissue which encircles the urethra as far as the anterior extremity of the veru montanum. In the contracted state of the urethra, the veru montanum acts as a valve, being pressed upwards against the upper wall of the canal; but, during the action of the detrusor mus- cle of the bladder, the whole ring is expanded by the longitudinal muscular fibres which are inserted into it; and the veru is especially draw7n down by two delicate tendons, which have been traced by Mr. Tyrrell from the posterior fibres of the detrusor into the tissue of this process. The Membranous portion, the narrowest part of the canal, is somewhat less than an inch in length. It is situated between the two layers of the deep perineal fascia, and is surrounded by the fan-like expansions of the upper and lower segments ofthe compressor urethrae muscle, which meet at the raphe along its upper and lower surface. It is continuous posteriorly with the prostatic urethra, and anteriorly with the spongy portion of the canal. Its coverings are, the mucous membrane, elastic fibrous layer, compressor urethrae muscle, and a partial sheath from the deep perineal fascia. The Spongy portion forms the rest of the extent of the canal, and is lodged in the corpus spongiosum from its commencement at the deep perineal fascia to the meatus urinarius. It is narrowest in the body, and becomes dilated at either extremity, posteriorly in the bulb, where it is named the bulbous portion, and anteriorly in the glans penis, where it forms the fossa navicularis. The meatus urinarius is the most constricted part of the canal; so that a catheter, which will enter that opening, may be passed freely through the whole extent of a normal urethra. Opening into the bulbous portion are two small excretory ducts about three-quar- ters of an inch in length, which may be traced backwards, between the coats of the urethra and the bulb, to the interval between the two layers * The bulbous, membranous, and prostatic urethra, with part ofthe bladder. 1. Part ofthe urinary bladder; its internal surface. 2. The trigonum vesicae. 3. The openings ofthe ureters. 4. The uvula vesicae. 5. The veru montanum. 6. The opening ofthe sinus pocularis. 7, 7. The apertures of the ejaculatory ducts. 8, 8. The openings of the prostatic ducts. The numbers 7, 7, and 8, 8, are placed on the cut surface of the supra-urethral portion of the prostate gland. 9, 9. The lateral lobes Of the prostate gland. a The membranous portion of the urethra. 6, b. Cowper's glands, c, c. The apertures of the excretory ducts of Cowper's glands, d. The commencement of the bulbous por- tion ofthe urethra, e, e. The upper surface ofthe bulb of the corpus spongiosum. /./. The crura penis, g, g- The corpus cavernosum. h. The spongy portion ofthe urethra. 540 SCROTUM--SPERMATIC CORD. of the deep perineal fascia, where they ramify in two small lobulated and somewhat compressed glands, of about the size of peas. These are Cow- per's glands; they are situated immediately beneath the membranous por- tion of the urethra, and are enclosed by the lower segment of the com- pressor urethrae muscle, so as to be subject to muscular compression. Upon the whole of the internal surface of the spongy portion of the urethra, particularly along its upper wall, are numerous small openings or lacunae, which are the apertures of mucous glands situated in the submucous areo- lar tissue. The openings of these lacunae are directed forwards, and are liable occasionally to intercept the point of a small catheter in its passage into the bladder. At about an inch and a half from the opening of the meatus, one of these lacunae is generally found much larger than the rest, and is named the lacuna magna. In a preparation of this lacuna, made by Sir Astley Cooper, the extremity of the canal presents several large primary ramifications. TESTES. The testes are two small glandular organs suspended from the abdomen by the spermatic cords, and enclosed in an external tegumentary covering, the scrotum. The Scrotum is distinguished into two lateral halves or hemispheres by a raphe, which is continued anteriorly along the under surface of the penis, and posteriorly along the middle line of the perineum to the anus. Of these two lateral portions the left is somewhat longer than the right, and corresponds with the greater length of the spermatic cord on the left side. The scrotum is composed of two layers, the integument and a proper covering, the dartos; the integument is extremely thin, transparent, and abundant, and beset by a number of hairs which issue obliquely from the skin, and have prominent roots. The dartos is a thin layer of contractile fibrous tissue, intermediate in properties betwreen muscular fibre and elastic tissue ; it forms the proper tunic of the scrotum, and sends inwards a dis- tinct septum (septum scroti), w-hich divides it into two cavities for the two testes. The dartos is continuous around the base of the scrotum with the common superficial fascia ofthe abdomen and perineum. The Spermatic cord is the medium of communication between the testes and the interior of the abdomen ; it is composed of arteries, veins, lymphatics, nerves, the excretory duct of the testicle, and investing tunics. It commences at the internal abdominal ring, where the vessels of which it is composed converge, and passes obliquely along the spermatic canal; the cord then escapes at the external abdominal ring, and descends through the scrotum to the posterior border of the testicle. The left cord is some- what longer than the right, and permits the left testicle to reach a lower level than its fellow. The Arteries of the spermatic cord are, the spermatic artery from the aorta; the deferential artery, accompanying .the vas deferens, from the superior vesical; and the cremasteric branch from the epigastric artery. The spermatic veins form a plexus, which constitutes the chief bulk of the cord ; they are provided with valves at short intervals, and the smaller veins have a peculiar tendril-like arrangement w-hich has obtained for them the name of vasa pampiniformia. The lymphatics are of large size, and terminate in the lumbar glands. The nerves are the spermatic plexus, TESTES--EPIDIDYMIS. 541 which is derived from the aortic and renal plexus, the genitai branch of the genito-crural nerve, and the scrotal branch of the ilio-scrotal. The Vas deferens, the excretory duct of the testicle, is situated along the posterior border of the cord, where it may easily be distinguished by the hard and cordy sensation which it communicates to the fingers. Its parietes are very thick and tough, and its canal extremely small, and lined by the mucous membrane continued from the urethra. The Coverings of the spermatic cord are, the spermatic fascia, cremaster muscle, and fascia propria. The spermatic fascia is a prolongation of the intercolumnar fascia, derived from the borders of the external abdominal ring during the descent of the testicle in the foetus. The cremasteric co- vering (erythroid) is the thin muscular expansion formed by the spreading out of the fibres of the cremaster, which is likewise carried down by the testis during its descent. The fascia propria is a continuation of the infundibuliform process from the transversalis fascia, which immediately invests the vessels of the cord, and is also obtained during the descent of the testis. Fig. 238.* TESTES. The Testis (testicle) is a small oblong and rounded gland, somewhat compressed upon the sides and behind, and suspended in the cavity of the scrotum by the spermatic cord. Its position in the scrotum is oblique; so that the upper extremity is directed upwards and forwards, and a little out- wards ; the lower, downw7ards and backwards, and a little inwards; the convex border looks forwards and downwards, and the flattened border, to which the cord is attached, backwards and upwards. Lying against its outer and posterior body is a flattened body which follows the course of the testicle, and extends from its upper to its lower extremity; this body is named, from its relation to the testis, epi- didymis (M, upon, 6/du(xoe, the testicle); it is divided into a central part or body, an upper extremity or globus major, and a lower extremity, globus minor (cauda) epididymis. The globus major is situated against the upper end of the testicle, to which it is closely adherent; the globus minor is placed at its low7er end, is attached to the testis by areolar tissue, and curves upwards, to become continuous with the vas deferens. The testis is invested by three tunics, tunica vagi- nalis, tunica albuginea, and tunica vasculosa, and is connected to the inner surface of the dartos by a large quantity of extremely loose areolar tissue, * A transverse section of the testicle. 1. The cavity of the tunica vaginalis: the most external layer is the tunica vaginalis reflexa; and that in contact with the organ, the tunica vaginalis propria. 2. The tunica albuginea. 3 The mediastinum testis, giving off numerous fibrous cords in a radiated direction to the internal surface of the tunica albu-inea The cut extremities of the vessels below the number belong to the rete testis*- and tho«e above, to the arteries and veins of the organ. 4. The tunica vascu- losa or nia mater testis. 5. One of the lobules, consisting of the convolutions of the ubuli seminiferi, and terminating by a single duct, the vas rectum. Corresponding lobules ar^ seen betWeen the other fibrous cords of the mediastinum. 6. Section of the epididymis. 46 542 STRUCTURE OF THE TESTIS. in which fat is never deposited, but which is very susceptible of serous infiltration. The Tunica vaginalis is a pouch of serous membrane derived from the peritoneum in the descent of the testis, and afterwards obliterated from the abdomen to within a short distance of the gland. Like other serous coverings, it is a shut sac, investing the organ, and thence reflected so as to form a bag around its circumference: hence it is divided, into the tunica vaginalis propria, and tunica vaginalis reflexa. The tunica vagi- nalis propria covers the surface of the tunica albuginea, and surrounds the epididymis, connecting it to the testis by means of a distinct duplicature. The tunica vaginalis reflexa is attached by its external surface, through the medium of a quantity of loose areolar tissue, to the inner surface of the dartos. Between the two layers is the smooth surface of the shut sac, moistened by its proper secretion. The Tunica albuginea (dura mater testis) is a thick fibrous membrane, of a bluish white colour, and the proper tunic of the testicle. It is adhe- rent externally to the tunica vaginalis propria, and from the union of a serous with a fibrous membrane is considered to be a fibro-serous mem- brane, like the dura mater and pericardium. After surrounding the tes- ticle, the tunica albuginea is reflected from its posterior border into the interior of the gland, and forms a projecting longitudinal ridge, which is called the mediastinum testis (corpus Highmorianum*), from which nume- rous fibrous cords (trabeculae, septula) are given off, to be inserted into the inner surface of the tunic. The mediastinum serves to contain the vessels and ducts of the testicle in their passage into the substance of the organ, and the fibrous cords are admirably fitted, as has been shown by Sir Astley Cooper, to prevent compression of the gland. If a transverse section be made of the testis, and the surface of the mediastinum examined, it will be observed that the blood-vessels of the substance of the organ are situated near the posterior border of the mediastinum, while the divided ducts of the rete testis occupy a place nearer the free margin. The Tunica vasculosa (pia mater testis) is the nutrient membrane of the testis; it is situated immediately within the tunica albuginea, and encloses the substance of the gland, sending processes inwards between the lobules, in the same manner that the pia mater is reflected between the convolu- tions of the brain. The substance of the testis consists of numerous conical flattened lobules (lobuli testis), the bases being directed towards the surface of the organ, and the apices towards the mediastinum. Krause found between four and five hundred of these lobules in a single testis. Each lobule is invested by a distinct sheath, formed of two layers, one being derived from the tunica vasculosa, the other from the tunica albuginea. The lobule is com- posed of one or several minute tubuli, tubuli seminiferi,] exceedingly con- voluted, anastomosing frequently with each other near their extremities, terminating in loops or in free caecal ends, and of the same diameter (y^g * Nathaniel Highmore, a physician of Oxford, in his "Corporis Humani Disquisitio Anatomica," ptiblished in 1651, considers the corpus Highmorianum as a duct formed by the convergence of the fibrous cords, which he mistakes for smaller ducts. j-Lauth estimates the whole number of tubuli seminiferi in each testis at 840, and their average length at 2 feet 3 inches. According to this calculation, the whole length of the tubuli seminiferi would be 1890 feet. STRUCTURE OF THE EPIDIDYMIS. 543 bright Fig. 239* of an inch, Lauth) throughout. The tubuli seminiferi are of i yellow colour; they become less convoluted in the apices of the lobules, and terminate by forming be- tween twenty and thirty small straight ducts of about twice the diameter of the tubuli seminiferi, the vasa recta. The vasa recta enter the substance of the mediastinum, and terminate in from seven to thirteen ducts, smaller in diameter than the vasa recta. These ducts pursue a waving course from below upwards through the fibrous tissue of the mediastinum ; they communicate freely with each other, and constitute the rete testis. At the upper extremity of the medi- astinum, the ducts of the rete testis terminate in from nine to thirty small ducts, the vasa ejferentia,\ which form by their convolutions a series of conical masses, the coni vasculosi; from the bases of these cones tubes of larger size proceed, w-hich constitute, by their complex convolutions, the body of the epi- didymis. The tubes become gradually larger towards the lower end of the epididymis, and terminate in a single large and convoluted duct, the vas deferens. The Epididymis is formed by the convolutions of the excretory seminal ducts, externally to the testis, and previously to their termination in the vas deferens. The more numerous convolutions and the aggregation of the coni vasculosi at the upper end of the organ constitute the globus major; the continuation of the convolutions downwards is the body ; and the smaller number of convolutions of the single tube at the lower extre- mity, the globus minor. The tubuli are connected together by a very delicate areolar tissue, and are enclosed by the tunica vaginalis. A small convoluted duct, of variable length, is generally connected with the duct ofthe epididymis immediately before the commencement of the vas deferens. This is the vasculum aberrans of Haller ; it is attached to the epididymis by the areolar tissue in which that body is enveloped. Sometimes it becomes dilated towards its extremity, but more frequently retains the same diameter throughout. The Vas deferens may be traced upwards in the course of the seminal fluid, from the globus minor of the epididymis along the posterior part of the spermatic cord, and along the spermatic canal to the internal abdomi- nal ring. From the ring it is reflected inwards to the side of the fundus ofthe bladder, and descends along its posterior surface, crossing the direc- tion of the ureter, to the inner border of the vesicula seminalis. In this situation it becomes somewhat larger in size and convoluted, and termi- nates at the base of the prostate gland, by uniting with the duct of the vesicula seminalis and constituting the ejaculatory duct. The ejaculatory * Anatomy of the testis. 1, 1. The tunica albuginea. 2, 2. The mediastinum testis. 3 3. The lobuli testis. 4, 4. The vasa recta. 5. The rete testis. 6. The vasa effe- rentia of which six only are represented in this diagram. 7. The coni vasculosi, constituting the globus major of the epididymis. 8. The body of the epididymis 9. The Globus minor of the epididymis. 10. The vas deferens. 11. The vasculum aberrans. ,. T , , „ . . „, + Each vas efferens with its cone measures, according to Lautti, about 8 inches. Ihe entire length ofthe tubes composing the epididymis, according to the same authority, is about 21 feet. 544 FEMALE PELVIS. Fig. 240.* duct, which is thus formed by the junction of the duct of the vesicula seminalis with the vas deferens, passes forwards to the anterior extremity of the veru montanum, where it terminates by opening into the prostatic urethra. FEMALE PELVIS. The peculiarities in form of the female pelvis have already been ex- amined with the anatomy of the bones (p. 118). Its lining boundaries are the same with those of the male. The contents are, the bladder, vagina, uterus with its appendages, and the rectum. Some portion of the small intestines also occupies the upper part of its cavity. The Bladder is in relation with the ossa pubis in front, with the uterus behind, from which it is usually separated by a convolution of small in- testine, and with the neck of the uterus and vagina beneath. The form of the female bladder corresponds with that of the pelvis, being broad from side to side, and often bulging more on one side than on the other. This is particularly evident after frequent parturition. The coats of the bladder are the same as those of the male. The Urethra is about an inch and a half in length, and is lodged in the upper wall of the vagina, in its course downwards and forwards, beneath the arch of the os pubis, to the meatus urinarius. It is lined by mucous membrane, which is disposed in longitudinal folds, and is continuous in ternally with that of the bladder, and externally with that of the vulva, the mucous membrane is surrounded by a proper coat of elastic tissue, to which the muscular fibres ofthe detrusor urinae are attached. It is to the elastic tissue that is due the remarkable dilatability of the female urethra, * Human testis injected with mercury. 1, 1. Lobules formed of seminiferous tubes. 2. Rete testis. 3. Vasa efferentia. 4. Plexuses.of the efferent vessels passing into the head of the epididymis 5, 5. 6. Body of the epididymis. 7. Its appendix; its tail or cauda. 8. Vas deferens.—(Lauth.) FEMALE PELVIS—VAGINA. 545 Fig. 241 * and its speedy return to its original diameter. The meatus is encircled by a ring of fibrous tissue, which prevents it from distending with the same facility as the rest of the canal; hence it is sometimes advantageous in performing this operation to divide the margin of the meatus slightly with the knife. VAGINA. The Vagina is a membranous canal, leading from the vulva to the uterus, and corresponding in direction with the axis of the outlet of the pelvis. It is constricted at its commencement, but near the uterus becomes dilated; and is closed by the contact of the anterior with the posterior wall. Its length is variable ; but it is always longer upon the posterior than upon the anterior wall, the former being usually about five or six inches in length, and the latter four or five. It is attached to the cervix ofthe uterus, which latter projects into the upper extremity ofthe canal In Structure the vagina is composed of a mucous lining, a layer of erectile tissue, and an external tunic of contractile fibrous tissue, resembling the dartos of the scrotum. The upper fourth of the posterior wall of the * A side view of the viscera of the female pelvis. 1. The symphysis pubis; to the upper part of which the tendon of the rectus muscle is attached. 2. The abdominal parietes. 3. The collection of fat, forming the prominence of the mons Veneris. 4. The urinary bladder. 5. The entrance ofthe left ureter. 6. The canal ofthe urethra, con- verted into a mere fissure by the contraction of its walls. 7. The meatus urinarius. 8. The clitoris, with its praeputium, divided through the middle. 9. The left nympha. 10. The left labium majus. 11. The meatus of the vagina, narrowed by the contraction of its sphincter. 12. 22. The canal of the vagina, upon which the transverse ruga? are apparent. 13. The thick wall of separation between the base of the bladder and the vagina. 14. The wall of separation between the vagina and rectum. 15. The perineum. 16 The os uteri. 17. Its cervix. IS. The fundus uteri. The cavitas uteri is seen along the centre of the organ. 19. The rectum, showing the disposition of its mucous mem- brane 20. The anus. 21. The upper part of the rectum, invested by the peritoneum. 23 The utero-vesical fold of peritoneum. The recto-uterine fold is seen between the rectum and the posterior wall ofthe vagina. 24. The reflexion ofthe peritoneum, from the apex of the bladder upon the urachus to the internal surface of the abdominal pa- rietes 25 The last lumbar vertebra. 26. The sacrum. 27. The coccyx. 46* 2k 546 VAGINA--UTERUS. vagina is covered, on its pelvic surface, by the peritoneum; while in front the peritoneum is reflected from the upper part of the cervix ofthe uterus to the posterior surface of the bladder. On each side it gives attachment, superiorly, to the broad ligaments of the uterus; and, inferiorly, to the pelvic fascia and levatores ani. The Mucous membrane presents a number of transverse papilla or ruga upon the upper and lower surfaces of the canal, the rugae extending out- wards on each side from a middle raphe. The transverse papillae and raphe are more apparent upon the upper than upon the lower surface, and the two raphe are called the columns of the vagina. The mucous mem- brane is covered by a thin cuticular epithelium, which is continued from the labia, and terminates by a fringed border at about the middle of the cervix uteri. The Middle or erectile layer consists of erectile tissue enclosed betw-een two layers of fibrous membrane ; this layer is thickest near the commence- ment of the vagina, and becomes gradually thinner as it approaches the uterus. The External, or dartoid layer of the vagina, serves to connect it to the surrounding viscera. Thus, it is very closely adherent to the under sur- face of the bladder, and drags that organ down with it in prolapsus uteri. To the rectum it is less closely connected, and that intestine is therefore less frequently affected in prolapsus. UTERUS. The Uterus is a flattened organ of a pyriform shape, having the base directed upwards and forwards, and the apex downwards and backwards in the line of the axis of the inlet of the pelvis, and forming a considerable angle with the course of the vagina. It is convex on its posterior surface, and somewhat flattened upon its anterior aspect. In the unimpregnated state it is about three inches in length, two in breadth across its broadest Fig. 242* * The uterus with its appendages viewed on their anterior aspect. 1. The body of the uterus. 2. Its fundus. 3. Its cervix. 4. The os uteri. 5. The vagina; the num- ber is placed on the posterior raphe or columna, from which the transverse rugse are seen passing off at each side. 6, 6. The broad ligament ofthe uterus. 7. A convexity of the broad ligament formed by the ovary. 8, 8. The round ligaments of the uterus. 9, 9. The Fallopian tubes. 10, 10. The fimbriated extremities of the Fallopian tubes; on the left side the mouth of the tube is turned forwards in order to show its ostium abdominale. 11. The ovary. 12. The utero-ovarian ligament. 13. The Fallopio-ova- rian ligament, upon which some small fimbriae are continued for a short distance. 14. The peritoneum ofthe anterior surface of the uterus. This membrane is removed on the left side, but on the right is continuous with the anterior layer of the broad ligament. STRUCTURE OF THE UTERUS. 547 part, and one in thickness, and is divisible into fundus, body, cervix, and os uteri. At the period of puberty the uterus weighs about one ounce and a half; after parturition from two to three ounces; and at the ninth month of utero-gestation from two to four pounds. The Fundus and body are enclosed in a duplicature of peritoneum, which is connected with the sides of the pelvis, and forms a transverse septum between the bladder and rectum. The folds formed by this du- plicature of peritoneum on either side ofthe organ are the broad ligaments of the uterus. The cervix is the lower portion of the organ ; it is distin- guished from the body by a well-marked constriction ; around its circum- ference is attached the upper end of the vagina, and at its extremity is an opening which is nearly round in the virgin, and transverse after parturi- tion, the os uteri, bounded before and behind by two labia; the anterior labium being the most thick, and the posterior somewhat the longest. The opening of the os uteri is of considerable size, and is named the ori- ficium uteri externum ; the canal then becomes narrowed, and at the upper end of the cervix is constricted into a smaller opening, the orificiura internum.* At this point the canal ofthe cervix expands into the shallow triangular cavity of the uterus, the infe- rior angle corresponding with the ori- r'g- 243-t ficium internum, and the two superior angles, which are funnel-shaped, and re- present the original bicornute condition of the organ, with the commencement of the Fallopian tubes. In the canal of the cervix uteri are two or three longitudinal folds, to which numerous oblique folds converge so as to give the idea of branches from the stem of a tree ; hence this appearance has been denominated the arbor vite uterina. Between these folds, and around the os uteri, are nu- merous mucous follicles. It is the closure of the mouth of one of these follicles, and the subsequent distention of the follicle with its proper secretion, that occasions those vesicular appearances, so often noticed within the mouth and cervix of the uterus, called the ovula of Naboth. Structure.—The uterus is composed of three tunics: of an external or serous coat, derived from the peritoneum, which constitutes the duplicatures on each side of the organ called the broad ligaments ; of a middle or muscu- lar coat, which gives thickness and bulk to the uterus; and of an internal or mucous membrane, winch lines its interior, and is continuous on the one hand with the mucous lining of the Fallopian tubes, and on the other with that of the vagina. In the unimpregnated state the muscular coat is ex- ceedinoiy condensed in texture, offers resistance to section with the scalpel, * The orificium internum is not unfrequently obliterated in old persons. Indeed, this obliteration is so common, as to have induced Mayer to regard it as normal. + S t'on of the uterus (transverse). The two bristles are introduced into the orifice* of the Fallopian tubes. 548 VESSELS AND NERVES OF THE UTERUS. and appears to be composed of whitish fibres inextricably interlaced and mingled with blood-vessels. In the impregnated uterus the fibres are of large size, and distinct, and are disposed in two layers, superficial and deep. The superficial layer consists of fibres which pursue a vertical direction, some being longitudinal, and others oblique. The longitudinal fibres are found principally on the middle line, forming a thin plane upon the anterior and posterior face of the organ and upon its fundus. The oblique fibres occupy chiefly the sides and the fundus. At the angles of the uterus the fibres of the superficial layer are continued outwards upon the Fallopian tubes, and into the round ligaments and ligaments of the ovaries. The deep layer consists of tw7o hollow cones of circular fibres having their apex at the openings of the Fallopian tubes, and intermin- gling with each other by their bases on the body of the organ. These fibres are continuous with the deep muscular layer of the Fallopian tubes, and indicate the primitive formation of the uterus by the blending of these two canals. Around the cervix uteri the muscular fibres assume a circular form interlacing with and crossing each other at acute angles. The mucous membrane is provided with a columnar ciliated epithelium, which extends from the middle ofthe cervix uteri to the extremities ofthe Fallo- pian tubes. Vessels and Nerves.—The Arteries of the uterus are the uterine from the internal iliac, and the spermatic from the aorta. The Veins are large and remarkable; in the impregnated uterus they are called sinuses, and consist of canals channeled through the substance of the organ, being merely lined by the internal membrane of the veins. They terminate on each side of the uterus in the uterine plexuses. The lymphatics terminate in the lumbar glands. The Nerves of the uterus are derived from the hypogastric and sper- matic plexuses, and from the sacral plexus. They have been made the subject of special investigation by Dr. Robert Lee, who has successfully repaired the omission made by Dr. William Hunter, in this part of the anatomy of the organ. In his numerous dissections of the uterus, both in the unimpregnated and gravid state, Dr. Lee has made the discovery of several large nervous ganglia and plexuses. The principal of these, situ- ated on each side of the cervix uteri, immediately behind the ureter, he terms the hypogastric ganglion; it receives the greater number of the nerves from the hypogastric and sacral plexus, and distributes branches to the uterus, vagina, bladder, and rectum. Of the branches to the uterus, a large fasciculus proceeds upwards by the side of the organ towards its angle, where they communicate with branches of the spermatic plexus, and form another large ganglion, which he designates the spermatic gan- glion, and which supplies the fundus uteri. Besides these, Dr. Lee de- scribes vesical and vaginal ganglia, and anterior and posterior subperitoneal ganglia and plexuses, which communicate with the preceding, and consti- tute an extensive nervous network over the entire uterus. Dr. Lee con- cludes his observations by remarking:—"These dissections prove that the human uterus possesses a great system of nerves, which enlarges with the coats, blood-vessels, and absorbents, during pregnancy, and which returns after parturition to its original condition before conception takes place. It is chiefly by the influence of these nerves that the uterus performs the varied functions of menstruation, conception, and parturition, and it is solely by their means that the whole fabric of the nervous system sympa- APPENDAGES OF THE UTERUS. 549 thises with the different morbid affections of the uterus. If these nerves of the uterus could not be demonstrated, its physiology and pathology would be completely inexplicable."* APPENDAGES OF THE UTERUS. The Appendages ofthe uterus are enclosed by the lateral duplicatures of peritoneum, called the broad ligaments. They are the Fallopian tubes and ovaries. The Fallopian! tubes or oviducts, the uterine trumpets of the French writers, are situated in the upper border of the broad ligaments, and are connected with the superior angles of the uterus. They are somewhat trumpet-shaped, being smaller at the uterine than at the free extremity, and narrower in the middle than at either end. Each tube is about four or five inches in length, and more or less flexuous in its course. The canal of the Fallopian tube is exceedingly minute ; its inner extremity opens by means of the ostium uterinum into the upper angle of the cavity of the uterus, and the opposite end into the cavity ofthe peritoneum. The free or expanded extremity of the Fallopian tube presents a double and sometimes a triple series of small processes or fringes, which surround the margin of the trumpet or funnel-shaped opening, the ostium abdominale. This fringe-like appendage to the end of the tube has gained for it the appellation of the fimbriated extremity ; and the remarkable manner in which this circular fringe applies itself to the surface of the ovary during sexual excitement, the additional title of morsus diaboli. A short liga- mentous cord proceeds from the fimbriated extremity to be attached to the distal end of the ovary, and serves to guide the tube in its seizure of that organ. The Fallopian tube is composed of three tunics, an external and loose investment derived from the peritoneum; a middle or muscular coat, con- sisting of circular [internal] and longitudinal [external] fibres, continuous with those of the uterus; and an internal or lining mucous membrane, which is continuous on the one hand with the mucous membrane of the uterus, and at the opposite extremity with the peritoneum. In the minute canal of the tube the mucous membrane is thrown into longitudinal folds or rugae, which indicate the adaptation of the tube for dilatation. The Ovaries are two oblong flattened and oval bodies of a whitish colour, situated in the posterior layer of peritoneum of the broad ligaments. They are connected to the upper angles of the uterus at each side by means of a rounded cord, consisting chiefly of muscular fibres derived from the uterus, the ligament of the ovary. By the opposite extremity they are connected by another and a shorter ligament to the fimbriated aperture of the Fallopian tube. In structure the ovary is composed of a cellulo-fibrous parenchyma or stroma traversed by blood-vessels, and enclosed in a capsule consisting of three layers: a vascular layer, which is situated most internally, and sends processes inwards to the interior of the organ ; a middle or fibrous layer of considerable density, and an external investment of peritoneum. * Philosophical Transactions for 1842. + Gabriel Fallopius, a nobleman of Modena, was one of the founders of modern ana- tomv He was Professor at Ferrara, then at Pisa, and afterwards succeeded Yesalius at Padua. His principal observations are collected in a work, " Observationes Anato- mica-,'' which he published in 1561. 550 EXTERNAL ORGANS OF GENERATION. In the cells of the stroma of the ovary the small vesicles or ovisacs of the future ova, the Graafian vesicles, as they have been termed, are developed. There are usually about fifteen fully formed Graafian vesicles in each ovary ; and Dr. Martin Barry has shown that countless numbers of micro- scopic ovisacs exist in the parenchyma of the organ, and that very few out of these are perfected so as to produce ova. After conception, a yellow spot, the corpus luteum, is found in one or both ovaries. The corpus luteum is a globular mass of yellow, spongy tissue, traversed by white areolar bands, and containing in its centre a small cavity, more or less obliterated, which was originally occupied by the ovum. The interior of the cavity is lined by a puckered membrane, the remains ofthe ovisac. In recent corpora lutea, the opening by which the ovum escaped from the ovisac through the capsule of the ovary is dis- tinctly visible; when closed, a small cicatrix may be seen on the surface of the ovary in the situation of the opening. A similar appearance to the preceding, but of smaller size, and without a central cavity, is sometimes met with in the ovaries of the virgin; this is a false corpus luteum. Vessels and Nerves.—The Arteries of the ovaries are the spermatic; their nerves are derived from the spermatic plexus. The Round ligaments are two muscular and fibrous cords situated be- tween the layers of the broad ligaments, and extending from the upper angles of the uterus, and along the spermatic canals to the labia majora, in which they are lost. They are accompanied by a small artery, by several filaments of the spermatic plexus of nerves, and by a plexus of veins. The latter occasionally become varicose, and form a small tumour at the external abdominal ring, which has been mistaken for inguinal hernia. The round ligaments serve to retain the uterus in its proper po- sition in the pelvis, and, during utero-gestation, to draw the anterior sur- face of the organ against the abdominal parietes. EXTERNAL ORGANS OF GENERATION. The female organs of generation are divisible into the internal and ex- ternal : the internal are contained within the pelvis, and have been already described ; they are the vagina, uterus, ovaries, and Fallopian tubes. The external organs are the mons Veneris, labia majora, labia minora, clitoris, meatus urinarius, and the'opening ofthe vagina. The Mons Veneris is the eminence of integument, situated upon the front of the ossa pubis. Its are- olar tissue is loaded with adipose substance, and the surface covered with hairs. The Labia majora are two large longitudinal folds of integument, consisting of fat and loose areolar tissue. They enclose an elliptical fissure, the com- mon urino-sexual opening or vulva. The vulva receives the inferior opening of the urethra and va- gina, and is bounded anteriorly by the commissura superior, and posteriorly by the commissura inferior. Stretching across the posterior commissure is a small transverse fold, the frenulum labiorum or fourchette, ** which is ruptured during parturition ; and immedi- ately within this fold is a small cavity, the fossa MAMMARY GLANDS. 551 navicularis. The length of the perineum is measured from the posterior commissure to the margin of the anus, and is usually not more than an inch. The external surface of the labia is covered with hairs; the inner surface is smooth, and lined by mucous membrane, which contains a num- ber of sebiparous follicles, and is covered by a thin cuticular epithelium. The use of the labia majora is to favour the extension of the vulva during parturition; for, in the passage of the head of the foetus, the labia are un- folded and completely effaced. The Labia minora, or nymphce, are two smaller folds, situated within the labia majora. Superiorly they are divided into two processes, which surround the glans clitoridis, the superior fold forming the praeputium cli- toridis, and the inferior its fraenulum. Inferiorly, they diminish gradually in size, and are lost on the sides of the opening of the vagina. The nymphos consist of mucous membrane, covered by a thin cuticular epi- thelium. They are provided with a number of sebiparous follicles, and contain, in their interior, a layer of erectile tissue. The Clitoris is a small elongated organ situated in front of the ossa pubis, and supported by a suspensory ligament. It is formed by a small body, which is analogous to the corpus cavernosum of the penis, and, like it, arises from the ramus of the os pubis and ischium on each side, by two crura. The extremity of the clitoris is called its glans. It is composed of erectile tissue, enclosed in a dense layer of fibrous membrane, and is susceptible of erection. Like the penis, it is provided with two small muscles, the erectores clitoridis. At about an inch behind the clitoris is the entrance ofthe vagina, an el- liptical opening, marked by a prominent margin. The entrance to the vagina is closed in the virgin by a membrane of a semilunar form, which is stretched across the opening; this is the hymen. Sometimes the mem- brane forms a complete septum, and gives rise to great inconvenience by preventing the escape of the menstrual effusion. It is then called an im- perforate hymen. The hymen must not be considered a necessary accom- paniment of virginity, for its existence is very uncertain. When present, it assumes a variety of appearances: it may be a membranous fringe, with a round opening in the centre, or a semilunar fold, leaving an opening in front; or a transverse septum, having an opening both in front and be- hind ; or a vertical band with an opening at either side. The rupture of the hymen, or its rudimentary existence, gives rise to the appearance of a fringe of papillae around the opening of the vagina; these are called caruncule myrtiformes. The triangular smooth surface between the clitoris and the entrance of the vagina, which is bounded on each side by the upper portions of the nymphae, is the vestibule. At the upper angle of the vagina is an elevation formed by the promi- nence of the upper wall of the canal, and analogous to the bulb of the urethra of the male; and immediately in front of this tubercle, and sur- rounded by it, is the opening of the urethra, the meatus urinarius. MAMMARY GLANDS. The Mamma are situated in the pectoral region, and are separated from the pectoralis major muscle by a thin layer of superficial fascia. They exist in the male as well as in the female, but in a rudimentary state, 552 ANATOMY OF THE FCETUS. unless excited into growth by some peculiar action, such as the loss or atrophy of the testes. Their base is somewhat elliptical, the long diameter corresponding with the direction of the fibres of the pectoralis major muscle; and the left mamma is generally a little larger than the right. Near the centre of the convexity of each mamma is a small prominence of the integument, called the nipple, which is surrounded by an areola having a coloured tint. In the female before impregnation, the colour of the areola is a delicate pink; after impregnation, it assumes a brownish hue, which deepens in colour as pregnancy advances; and after the birth of a child, the brownish tint continues through life. The areola is furnished with a considerable number of sebiparous folli- cles, which secrete a peculiar fatty substance for the protection of the deli- cate integument around the nipple. During suckling these follicles are increased in size, and have the appearance of small pimples, projecting from the skin. At this period they serve by their increased secretion to defend the nipple and areola from the excoriating action of the saliva of the infant. In Structure, the mamma is a conglomerate gland, and consists of lobes, which are held together by a dense and firm areolar tissue; the lobes are composed of lobules, and the lobules of minute caecal vesicles, the ulti- mate terminations of the excretory ducts. The excretory ducts (tubuli lactiferi), from ten to fifteen in number, commence by small openings at the apex ofthe nipple, and pass inwards, parallel with each other, towards the central part of the gland, where they form dilatations (ampullae), and give off numerous branches to ramify through the gland to their ultimate terminations in the minute lobules. The ducts and caecal vesicles are lined, throughout, by a mucous mem- brane, which is continuous at the apex of the nipple with the integument. In the nipple the excretory ducts are surrounded by a tissue analogous to the dartos of the scrotum, to which the power of erectility of the nipple seems due. There is no appearance of any structure resembling erectile tissue. Vessels and Nerves. — The mammae are supplied with arteries from the thoracic branches of the axillary, from the intercostals, and from the in- ternal mammary. The Lymphatics follow the border of the pectoralis major to the axillary glands. %& LEA & BLANCHARD'S PUBLICATIONS— (Anatomy.) 1 THE STUDENT'S TEXT-BOOR OF ANATOMY. New and Improved Edition. Just Issued. A SYSTEM OF HUMAN ANATOMY, GENERAL AND SPECIAL. BY ERASMUS WILSON, M. D. FOURTH AMERICAN, FROM THE LAST ENGLISH EDITION. EDITED BY PAUL B. GODDA11D, A. M., M. D., With Two Hundred and Fifty Illustrations. Beautifully printed in One large Octavo Volume of nearly Six Hundred Pages. In many, if not all the Colleges ofthe Union, it has become a standard text-book. This, of itself, is sufficiently expressive of its value. A work very desirable to the student; one. the possession of which will greatly facilitate his progress in the study of Praclical Anaiomy.—New York Journal of Medicine. Its author ranks with the highest on Anatomy.— Southern Medical and Surgical Journal. It ofTers to the student all the assistance that can be expected from such a work.—Medical Examiner. The most complete and convenient manual for ihe student we possess.—American Journal of Med. Science. In every respect this work, as an anaiomieat guide for the student and practitioner, merits our warmest and most decided praise.—London Medical Gazette. HORNER'S ANATOMY. SPECIAL ANATOMY AND HISTOLOGY. BY WILLIAM E. HORNER, M. D., Professor of Anatomy in the University of Pennsylvania, &c. &c. SEVENTH EDITION. With many improvements and additions. In two Svo. vols, of 1130 pages, with illustrations on wood. It is altogether unnecessary now to inquire into the particular merits of a work which has been so long be- fore the profession, and is so well known as the present one ; but iu announcing a new edition, it is proper to state that it has undergone several modifications, and has been much extended, so as to place it on a level with the existing advanced stale of anaiomy. The histological portion has been remodelled and rewritten since the last edition ; numerous wood-cuts have been introduced, and specific references are made through- out the work to the beautiful figures in the Anatomical Atlas, by Dr. H. H. Smith.— The American Medical Journal. NEW AND CHEAPER EDITION.—Now Ready. AN ANATOMICAL ATLAS, ILLUSTRATIVE OF THE STRUCTURE OF THE HUMAN BODY. BY HENRY H. SMITH, M. D., &c. UNDER THE SUPERVISION OF WILLIAM E. HORNER, M. D., Professor of Anatomy in the University of Pennsylvania. In one large imperial octavo volume, with about 650 beautiful figures. With the view of extending the sale of this beautifully executed and complete " Anatomical At- las," the publishers have prepared a hew edition, printed on both sides of the page, thus materi- ally reducing its cost, and enabling them to present it at a price about forty per cent, lower than former editions, while, at the same time, the execution of each plate is in no respect deteriorated, and not a single figure is omitted. MACLISE'S SURGICAL ANATOMY. Now Ready, Part I. of SURGICAL ANATOMY. BY JOSEPH xMACLISE, Surgeon. To be complete in Four Parts, Imperial Quarto, with from Twelve to Sixteen handsomely Colored Plates each ; forming, when complete, a large Imperial Quarto Volume, With from Fifty to Sixty beautiful colored Plates, drawn on Stone, in the best style of art. Mr Maclise's work bids fair to redeem our country from the stisrma of possessing no original work on sur- trica! anaiomy that could take rank in regard to completeness and beauty of execution with many continental productions that might be named. We particularly approve of ihe manner m winch the parts are brought into view bv a succession of plates, no effort being made to show loo much, but lho*e parts only being displayed which are brought into view at one time by a good dissection. Thus, as a guide to the dissector, these plates will be far more valuable than such as endeavor to display the whole anaiomy of a complicated region in one or two drawings—Mr Maclise has presented us with admirable delineations and excellent descrip- tions — The British and Foreign Medico- Chirurgical Rfiiew. It is and it must be. unique, for the practical knowledge of the surgeon, the patience and skill ofthe dissector, m combination with the genius of the artist, as here displayed, have never before been, and perhaps never will be a«-ain, associated to a similar exient in the same individual —Lancet. The drawing are executed with the skill of the most accomplished anaiomist. and the coloring of the plates is done in such a manner as to reflect high credit on the artist— Medical Times. SUBSCRIPTION PRICE TWO DOLLARS A PART. 8 LEA & BLANCHARD'S PUBLICATIONS —(Physiology.) DUNGLISON'S HUMAN PHYSIOLOGY. HUMAN PHYSIOLOGY. WITH THREE HUNDRED AND SEVENTY ILLUSTRATIONS. BY EOBLEY DUNGLISON, M. D., PROFESSOR OF THE INSTITUTES OF MEDICINE IN THE JEFFEKSON MEDICAL COLLEGE, PHILADELPHIA, ETC. ETC. SIXTH EDITION, GREATLY IMPROVED, In two large octavo volumes, containing nearly 1350 pages. It has long since taken rank as one of the medical classics of our language. To say that it is by far the best texi-book of physiology ever published in this country, is but echoing the general testimony of the profession. — A'. Y. Journal of Medicine. The most full and complete system of Physiology in our language.— Western Lancet. The most complete and satisfactory system of Physiology in the English language.—Amer. Med. Journal. The best work ofthe kind in the English language.—Silliman's Journal. We have, ou two former occasions, brought this excellent work under the notice of our readers, and we have now only ,to say that, instead of failing behind in the rapid march of physiological science, each edition brings it nearer to the van.—British and Foreign Medical Review. A review of such a well-known work would be out of place at the present time. We have looked over it, and find, what we knew would be the case, that Dr. Dunglison has kept pace with the science to which he has devoted so much study, and of which he is one ofthe living ornaments. We recommend the work to the medical student as a valuable text-book, and lo all inquirers into Natural Science, as one which will well and delightfully repay perusal.— The New Orleans Medical and Surgical Journal. CARPENTER'S HUMAN PHYSIOLOGY—Now Ready. A NEW, MUCH IMPROVED AND ENLARGED EDITION OF THE PRINCIPLES OF HUMAN PHYSIOLOGY. WITH THEIR CHIEF APPLICATIONS TO PATHOLOGY, HYGIENE, AND FORENSIC MEDICINE. BY WILLIAM B. CAKPENTEK, M. D., F. R S., Fullerian Professor of Physiology in the Royal Institution of Great Britain ; author of " Elements of Physiology," " Principles of General and Comparative Physiology," " Principles of Animal Physiology," &c. &c. FOURTH AMERICAN EDITION, REVISED, CORRECTED, AND MUCH IMPROVED BY THE AUTHOR, FOR THIS COUNTRY. Containing 314 Wood-cuts, and Two Plates. In one large and beautifully printed octavo volume of over seven hundred and fifty pages, strongly bound. In preparing a new edition of this very popular text-book, the publishers have had it completely revised by the author, who, without materially increasing its bulk, has embodied in it all the recent investigations and discoveries in physiological science, and has rendered it in every respect on a level with the improvements ofthe day. Although the number of ihe woodnigravings has been but little increased, a considerable change will be found, many new and interesting illustraiions having been introduced in place of others which were considered unnecessary, or which the advance of science had shown to be imperfect, while the plates have been altered and redrawn under the supervision ofthe author by a competent London artist. In passing the volume through the press in this country, the services of a professional gentleman have been secured, in order to insure the accuracy so necessary lo a scientific work. In every point of typographical execution, therefore, it will be (bund equal to former editions. The publishers consequently hope that the present edition will be considered worthy of the extended reputation ofthe work, and fully entitled to maintain the promi- nent place which it occupies as a textbook for the student, and as a comprehensive epitome of all that is im- portant in the department of Human Physiology, for the practitioner. Notwithstanding these improvements, the price ofthe volume is maintained al its former moderate rate. This incomparable work.— Brit, and For. Medical Review. As a text-book, it has been received into all our Colleges, and, from a careful perusal of this edition, we can recommend it to the student and to the profession at large, as the liesi exposition ofthe present condition of Physiology within their reach.—N Y. Journal of Medicine. The work, as it row stands, is the only treatise on Physiology in the English language which exhibits a clear and connected, and comprehensive view ofthe present condition of that science—London and Edin- burgh Monthly Journal. The standard English treatise on Physiology.—London Medical Gazette Dr. Carpenter's productions justly hold the first rank in Physiology, and should be read by all who wish to keep pace with the rapid advances of the study — Southern Medical and Surgical Journal. Second to no work extant upon the subject of which it treats.— III. and Ind. Medical and Surgical Journal. We know of no work in our language from which the recent views on Physiology can be so well obtained, nor any in which the subjects are so ably discussed — St. Louis Medical and Surgical Journal. Peculiarly adapted to the Medical Student.—Medical Examiner. We have much satisfaction in declaring our opinion that this work is the best systematic treatise on Physiology in our own language, and the best adapted to the student in any language.—Medico- Chirurgical Review. A work to which there has been none paiblisked of equal value in the department of which it treats.— Dr. Black's Retrospective Address. From Professor Caldwell, of Louisville, Ky. "I have already recommended it. and will continue to do so. to my class, as one ofthe richest and sound- est repositories of physiological knowledge now in the English or any other language I am capable of reading." LEA & BLANCHARD'S PUBLICATIONS .—(Physiology.) COMPENDIUM OP MULLERS PHYSIOLOGY. A MANUAL OF~PHYSIOLOGY, FOR THE USE OF STUDENTS. BY WILLIAM SENHOUSE KIRKES, M. D., Assisted by JAMES PAGET, Lecturer on General Anatomy and Physiology in St. Bartholomew's Hospital. In One Handsome Volume, Royal 12mo., of Five Hundred and Fifty Pages. ILLUSTRATED WITH UPWARDS OF ONE HUNDRED WOOD ENGRAVINGS. This is, certainly, a most able manual of Physiology. The student will find in it, not a meagre outline, a bare skeleton ofthe leading particulars embraced in the science, but a very complete and accurate—though, at the same time, concise—account ofthe facts and generally admitted principles of Physiology ; forming an admirable introduction to the study of that science, as well as a useful compendium for consultation by those who are preparing for an examination. The whole ofthe illustrations are very excellent, and calculated to render the description of the objects ihey represent clear and precise. To those who stand in need of a Manual of Physiology—and works of this description have now become, in a certain sense, indispensable portions of the apparatus of study—we can very confidently recommend the present one as well for its com- prehensiveness as for its general accuracy— American Journal ofthe Medical Sciences. April, 1S49. An excellent work, and for students one ofthe best within reach— Boston Medical and Surgical Journal. A work very much wanted, bringing modern Physiology more within the student's grasp than its prede- cessors.— Dublin Medical Press. One ofthe best little books on Physiology which we possess.— BrailhwaiteH Retrospect- The authors have succeeded in producing a work well adapted for students.—Monthly Journal and Retro- spect ofthe Medical Sciences. Particularly adapted to those who desire to possess a concise digest of the facts of Human Physiology.— British and Foreign Med.-Chirurg. Review. One ofthe best treatises on Physiology which can be put into the hands of the student.— London Medical Gazette, March, 1849. We conscientiously recommend it lo our readers as an admirable "Handbook of Physiology."—London Journal of Medici ne. As an introduction to the study of the larger works, or as a reference for those who desire to "brush up" their knowledge, we most cordially recommend the manual of Kirkes and Paget to both practitioner and stu- dent, with the firm conviction that they will not be disappointed in the end they desire to attain.— The Medical Examiner. CARPENTER'S ELEMENTS. ELEMENTS OF PHYSIOLOGY, Including Physiological Anatomy.—For the nse of the Medical Student. BY WILLIAM B. CARPENTER, M. D., F. R. S., Fullerian Professor of Physiology in the Royal Institution of Great Britain, &c. With one hundred and eighty Illustrations. In one octavo volume of 566 pages. Elegantly printed, to match his " Principles of Human Physiology." The author has shown singular skill in preserving so marked a line of distinction between the present Manual and the " Principles of Physiology" previously published by him. They are both on precisely the same subject; but. the one is neither a copy, nor an abstract, nor an abridgment of the other. In one thing, however, they are exactly alike—in their general excellence, and in their perfect adaptation lo their respect- ive purposes.—British and Foreign Medical Review. SOLLY ON THE BRAIN. THE HUMAN BRAIN; ITS STRUCTURE, PHYSIOLOGY, AND DISEASES. WITH A DESCRIPTION OF THE TYPICAL FORM OF THE BRAIN IN THE ANIMAL KINGDOM. BY SAMUEL SOLLY, F. R. S., &c, Senior Assistant Surgeon to the St. Thomas' Hospital, &c. FROM THE SECOND AND MUCH ENLAR&ED LONDON EDITION. In One Octavo Volume ; with One Hundred and Twenty Wood-cuts. The most complete account of the anatomy, physiology, and pathology of the brain that has hitherto ap- peared. We earnestly advise all our professional brethren lo enrich their libraries with this admirable treatise.—Medico- Chirurgical Review. HARRISON ON THE NERVES.—An Essay towards a correct theory of the Nervous System. Inone octavo volume, '202 pagt s. MATTEUCCI ON LIVING BEINGS.—Lectures on the Physical Phenomena of Living Beings. Edited by Pereira. In one neat royal 12mo. volume, extra cloth, with cuts—38S pages. ROGET'S PHYSIOLOGY.—A Treatise on Animal and Vegetable Physiology, with over 400 illustrations on wood. In two octavo volumes, cloth. ROGET'S OUTLINES—Outlines of Physiology and Phrenology. In one octavo volume, cloth—516 pages. ON THE CONiNF-CTlON BETWEEN PHYSIOLOGY AND INTELLECTUAL SCIENCE. Inone 12mo. volume, paper, price 25 cents. TODT) & BOWMAN'S PHYSIOLOGY—Physiological Anatomy and Physiology of Man. With numerous handsome wood-cuts. Three-fourths of this work have appeared in the Medical News and Library; the onclu«ion may be expected this year, when those who have the commencement will be enabled to procure the completion. 10 LEA & BLANCHARD'S PUBLICATIONS —(Pathology.) WILLIAMS' PRINCIPLES—New and Enlarged Edition. PRINCIPLES OF MEDICINE; Comprising General Pathology and Therapeutics, AND A Brief general view of Etiology, Nosology, Semeiology, Diagnosis, Prognosis, and Hygienics. BY CHARLES J. B. WILLIAMS, M. D., F. R. S., Fellow of ihe Royal College of Physicians. Sec. Edited, with Additions, BY MEREDITH CLYMER, M. D., Consulting Physician to ihe Philadelphia Hospital, kc. &c. THIRD AMERICAN, FROM THE SECOND AND ENLARGED LONDON EDITION. In one volume, octavo, of 440 pages. The best exposition in our language, or, we believe, in any language, of Rational Medicine, in its present improved and rapidly improving state.—Britishand Foreign Medico-Chirurg. Review. We recommend every part of Dr. Williams' excellent Principles of Pathology to the diligent perusal of every physician who is not familiar with the accessions which have been made to medical science within the last few years.— Western Journal of Medicine and Surgery. From Professor Thayer, of Boston. It fills the place for which it was intended better than any other work. From Professor S. H. Dickson, of New York. I shall be truly glad to know that a copy of it is in the hands of every member of our profession. As a public teacher, I know not how I could dispense with it. MANUALS ON Tmi^LOOD AND URINE: CONSISTING of I. A Practical Manual, containing a description ofthe General, Chemical, and Microscopical Char- acters ofthe Blood and Secretions ofthe Human Body, as well as of their compounds, including both their healthy and diseased states; with the best method of separating and estimating their ingredients. Also, a succinct account of the various concretions occasionally found in the body, and forming calculi. BY JOHN WILLIAM GRIFFITH, M. D., F. L. S., &c. II. On the Analysis ofthe Blood and Urine in health and disease, and on the treatment of Urinary diseases. BY G. OWEN REESE, M. D., F. R. S., &c. &c. III. A Guide to the Examination ofthe Urine in health and disease, for the use of students. BY ALFRED MARKWICK. The whole forming one large royal ]2mo. volume, of four hundred and sixty pages, With about one hundred figures on five plates. Although addressed especially to students, it contains almost all the information upon these matters which the practitioner requires—Dublin Medical Press. The chemical processes recommended are simple, yet scientific ; and the work will be very useful to the medical alumni for whom it is intended.—Medical Times. The author must be admitted to have attained his object in presenting a convenient bedside companion.— Dr. Ranking^ Abstract. THE PATHOLOGICAL ANATDMTToP THE HUMAN BODY. BY JULIUS VOGEL, M. D., &c. TRANSLATED FROM THE GERMAN, WITH ADDITIONS, BY GEORGE E. DAY, M. D., &c. Illustrated by upwards of One Hundred Plain and Colored Engravings, In one neat octavo volume. It is decidedly the best work on the subject of which it treats, in the English language; and Dr. Day, whose translation is well executed, has enhanced its value by a judicious selection of the most important figures from the atlas, which are neatly engraved.—The London Medical Gazette. ALISON'S PATHOLOGY—Outlines of Pathology and Practice of Medicine; containing Preliminary Ob- servations. Inflammatory and Febrile Diseases, and Chronic or non-Febrile Diseases. In one neat Svo. volume, pp. 420. ABERCROMBIE ON THE STOMACH.—Pathological and Practical Researches on Diseases of the Stomach, Intestinal Canal, &c. Fourth Edition. One small Svo. volume, pp. 321). ABERCROMBIE ON THE BRAIN.-Pathological and Practical Researches on Diseases of the Brain and Spinal Cord. A new edition, in one small 8vo. volume, pp. 324. BURROWS ON CEREBRAL CIRCULATION.—On Disorders of the Cerebral Circulation, and on the Connection between Affections of the Brain and Diseases of the Heart. In one Svo. vol., with colored plates, pp. 216. BLAKISTON ON THE CHEST.—Practical Observations on certain Diseases of the Chest, and on the Principles of Auscultation. In one volume, Svo., pp. 3S4. BII.LTNG'S PRINCIPLES.—The First Principles of Medicine. From the Fourth London Edition. In one volume, 8vo., pp. 304. BIRD ON URINARY DEPOSITS.—Urinary Deposits, their Diagnosis, Pathology, and Therapeutical Indi- cations. In one volume, Svo., pp. 22S. HASSES PATHOLOGICAL ANATOMY.—An Anatomical Descriptionof the Diseasesof Respiration and Circulation. Translated and Edited by Swaine. In one volume, Svo., pp. 379. HUGHES ON THE LUNGS AND HEART.—Clinical Introduction to ihe I'ractice of Auscultation, and other modes of Physical Diagnosis. 1 mended to simplify the study ofthe Diseases ofthe Heart and Lungs. In one 12mo. volume, with a plate, pp. 270. WALSI1E ON THE LUNGS.—Physical Diagnosis ofthe Diseasesof the Lungs. In one 12mo. vol., pp. 310. LEA &. BLANCHARD'S PUBLICATIONS.—(Practice of Medicine.) 11 DUNGLISON'S PRACTICE OF MEDICINE. ENLARGED AND IMPROVED EDITION. THE PRACTICeToF MEDICINE; A TREATISE ON SPECIAL PATHOLOGY AND THERAPEUTICS. THIRD EDITION. BY ROBLEY DUNGLISON, M. D., Professor ofthe Institutes of Medicine in the Jefferson Medical College; Lecturer on Clinical Medicine, $c. In Two large Octavo Volumes of Fifteen Hundred Pages. In Dr. Dunglison's volumes, there is a kind of pervading exactness on every page, that is at once recognized; and, in fact, the medica] public has long since decided that implicit reliance may be placed on any work which he permits to appear with his name upon the title-page. A third edition of his treatise on Special Pathology and Therapeutics has just been published. It has pass- ed through so many careful examinations, and received so many improvements, under the vigilant eye ofthe indefatigable man who first gave it existence, that it would be an anomaly in medical iiterature if it had not grown better and better. The student of medicine will find, in these two elegant volumes, a mine of facts, a gathering of precepts and advice from the world of experience, that will nerve him with courage, and faithfully direct him in his efforts to relieve the physical suf- ferings ofthe race.—Boston Medical and Surgical Journal. Upon every topic embraced in the work the latest information will be found carefully posted up. Medical Examiner. Professor Dunglison's work has rapidly passed to the third edition, and is now presented to the profession as probably the most complete work on the Practice of Medicine that has appeared in our country. It is especially characterized by extensive and laborious research, minute and accu- rate pathological, semeiological, and therapeutical descriptions, together with that fulness of detail which is so important to the student. The present edition has been considerably enlarged ; indeed, the indefatigable author seems to have explored all the labyrinths of knowledge, from which important facts and opinions could be gleaned, for the instruction of his readers. We cheerfully commend the work to those who are not already familiar with its merits. It is certainly the most complete treatise of which we have any knowledge. There is scarcely a disease which the student will not find noticed.—Western Journal of Medicine and Surgery. One ofthe most elaborate treatises ofthe kind we have.—Southern Medical and Surg. Journal. The work of Dr. Dunglison is too well known, to require at our hands, at the present time, an analysis of its contents. The call for a third edition within five years from the appearance of the first, is, of itself, a sufficient evidence of the opinion formed of it by the medical profession of our country. That it is well adapted as a text-book for the use ofthe student, and at the same time as a book of reference for the practitioner, is very generally admitted ; in both points of view, for accu- racy and completeness, it will bear a very advantageous comparison with any of the numerous co- temporary publications on the practice of medicine, that have appeared in this country or in Europe. The edition before us bears the evidence of the author's untiring industry, his familiarity with the various additions which are constantly being made to our pathological and therapeutical knowledge, and his impartiality in crediting the general sources from which his materials have been derived. Several pathological affections, omitted in the former editions, are inserted in the present, while every portion of the work has undergone a very thorough revision. It may with truth be said, that nothing of importance that has been recorded since the publication of the last edition, has escaped the attention of the author; the present edition may, therefore, be regarded as an adequate exponent of the existing condition of knowledge on the important departments of medicine of which it treats.—The American Journal of the Medical Sciences. The Physician cannot get a better work of the kind than this, and when he masters its contents, he will have mastered all that such treatises can afford him.—St. Louis Med. fy Surg. Journal, June, 1848. In the volumes before us, Dr. Dunglison has proved that his acquaintance with the present facts and doctrines, wheresoever originating, is most extensive and intimate; and the judgment, skill, and impartiality with which the materials ofthe work have been collected, weighed, arranged, and ex- posed, are strikingly manifested in every chapter. Great care is everywhere taken to indicate the source of information, and under the head of treatment, formula! ofthe most appropriate remedies are everywhere introduced. In conclusion, we congratulate the students and junior practitioners of America on possessing in the present volumes a work of standard merit, to which they may con- fidently refer in their doubts and difficulties.—Brit, and For. Med. Review. Since the foregoing observations were written, we have received a second edition of Dunglison's work, a sufficient indication of the high character it has already attained in America, and justly attained.—Ibid. DAY ON OLD AGE—Now Ready. A PRACTICAL TREATISE ON THE DOMESTIC MANAGEMENT AND MORE IMPORTANT DISEASES OF ADVANCED LIFE. With an Appendix, containing a series of cases illustrative of a new and successful mode of treating rr Lumbago, and other forms of Chronic Rheumatism. BY GEORGE E. DAY, M. D. In One Octavo Volume. A more satisfactory and truly rational train of excellent suggestions have not been ushered into being for a long time than are contained in this work.—Boston Med. <$• Surg. Journal. 12 LEA & BLANCHARD'S PUBLICATIONS.—(Practice of Medicine.) WATSON'S PRACTICE OF MEDICINE—New Edition. I FTTURFS ON THP PRINCIPLES AND PRACTICE OF PHYSICS. DELIVERED AT KING'S COLLEGE, LONDON, BY THOMAS WATSON, M.D., &c. &c. Third American, from the last London Edition. REVISED, WITH ADDITIONS, BY D. FRANCIS CONDIE, M. D., Author of a Work on the "Diseases of Children," &c. In One Octavo Volume, Of nearly ELEVEN HUNDRED LARGE PAGES, strongly bound with raised bands. To say that it is the very best work on the subject now extant, is but to echo the sentiment of the medical press ihroughout the country.— N. O. Medical Journal. Of the text-hooks recently republished Watson is very justly the principal favorite.—Holmes'' Report to Nat. Med. Assoc. By universal consent the work ranks among the very best text-books in our language.— III. and Ind. Med. Journal. Regarded on all hands as one of the very best, if not the very best, systematic treatise on practical medi- cine extant—St. Louis Med. Journal. Confessedly one ofthe very best works on the principles and practice of physic in the English or any other language.—Med. Examiner. As a text-book it has no equal; as a compendium of pathology and practice no superior.— IV. Y. Annalist. We know of no work belter calculated for being placed in the hands of the student, and for a text-book. On every important point the author seems to have posted up his knowledge to the day.—Amer. Med. Journal. One of the most practically useful books that ever was presented to the student—indeed, a more admirable summary of general and special pathology, and of the application of therapeutics to diseases, we are free to say, has not appeared for very many years. The lecturer proceeds through the whole classification of human ills, a capite ad calcem, showing at every step an extensive knowledge of his subject, with the ability of com- municating his precise ideas in a style remarkable for its clearness and simplicity.—N. Y. Journal of Medi- cine and Surgery. A careful examination of this volume has satisfied us that it merits all the commendation bestowed on it in this country and at home. It is a work adapted to the wants of young practitioners, combining, as it does, sound principles and substantial practice. It is not too much to say that it is a representative of the actual state of medicine as taught and practised by the most eminent physicians of the present day. and as such we would advise every one about embarking in the practice of physic to provide himself with a copy of it.— Western Journal of Medicine and Surgery. We have for several years considered this one of the best works extant on the Principles and Practice of Medicine. Its style is adapted to all classes of readers, and the views of the author are sound and practical. —Mo. Med. and Surg. Journal. Whoever owns this book will have an acknowledged treasure, if the combined wisdom of the highest au- thorities is appreciated.— Boston Med. and Surg. Journal. It has now become, beyond all question, the standard work on the subject of which it treats; it is in the hands of every physician, surgeon, and senior medical student in every country in which the English lan- guage is spoken; it has passed scathless through the perils of criticism. Never, within the memory of authors or publishers,has a medical work in two thick octavo volumes attained the enormous circulation of Watson's Lectures, a third edition having been called for within the space of five years, and being, we believe, already nearly exhausted ; and, in addition to this, it must be recollected that these lectures also appeared in the Medi- cal Gazette, and have been reprinted in America. We mention these facts as affording a sufficient reason why, in attempting to do tardy justice to the merits of this work, our notice of it will be comparatively brief. A work that has passed through so many editions, and that is already so widely diffused through the profes- sion, is in one point of view, that is to say. in so far as any opinion of ours can influence its popularity, be- yond the critic's province.—Edinburgh Monthly Journal and Retrospect ofthe Medical Sciences. Much Enlarged Edition of BARTLETT ON FEVERS. THE HISTORY, DIAGNOSIS, AND TREATMENT OF THE FEVERS OF THE UNITED STATES. BY ELISHA BARTLETT, M. D., Professor of the Theory and Practice of Physic in the Medical Department of Transylvania University, &c. In One Octavo Volume of 550 Pages, Beautifully printed and strongly bound. We regard it, from the examination we have made of it, Ihe best work on fever extant in our lan^ua^e and as such cordially recommend it lo the medical public—Si. Louis Med. and Surg. Journal. The most complete, methodical, and satisfactory account of our fevers anywhere to be met with.—Charles- ton Med. Journ. and Review. CLYMER AND OTHERS ON FEVERS. FEVERS; THEIR DIAGNOSIS, PATHOLOGY, AND TREATMENT, PREPARED AND EDITED, WITH LARGE ADDITIONS, FROM THE ESSAYS ON FEVER IN TWEEDIE'S LIBRARY OP PRACTICAL MEDICINE, BY MEREDITH CLYMER, M.D. In One Octavo Volume of Six Hundred Pages. One of the best works we have on fevers, and especially adapted to the wants of the American physician. —IU. and Ind. Med. and Surg. Journal. LEA & BLANCHARD'S PUBLICATIONS— (Practice of Medicine.) 13 THE GREAT MEDICAL LIBRARY. THE CYCLOPEDIA OF PRACTICAL MEDICINE; COMPRISING Treatises on the Nature and Treatment of Diseases, Materia Medica, and Thera- peutics, Diseases of Women and Children, Medical Jurisprudence, Sec. &c. EDITED BY JOHN FORBES, M. D., F. R. S., ALEXANDER TWEEDIE, M. D., F. R. S., AND JOHN CONNOLLY, M. D. Revised, with Additions, BY ROBLEY DUNGLISON, M. D. THIS WORK IS NOW COMPLETE, AND FORMS FOUR LARGE SUPER-ROYAL OCTAVO VOLUMES, Containing Thirty-two Hundred and Fifty-four unusually large Pages in Double Columns, Printed on Good Paper, with a new and clear type. THE WHOLE WELL AND STRONGLY BOUND, WITH RAISED BANDS AND DOUBLE TITLES. Or, to be had in Twenty-four Parts. This work contains no less than FOUR HUNDRED AND EIGHTEEN DISTINCT TREATISES, BY SIXTY-EIGHT DISTINGUISHED PHYSICIANS. The most complete work on Practical Medicine extant; or, at least, in our language.—Buffalo Medical and Surgical Journal. For reference, it is above all price to every practitioner.— Western Lancet. One of the most valuable medical publications of the day—as a work of reference it is invaluable.— Western Journal of Medicine and Surgery. It has been to us, both as learner and teacher, a work for ready and frequent reference, one in which modern English medicine is exhibited in the most advantageous light.—Medical Examiner. We rejoice that this work is to be placed within the reach ofthe profession in this country, it being unques- tionably one of very great value to the practitioner. This estimate of it has not been formed from a hasty ex- amination, but after an intimate acquaintance derived from frequent consultation of it during the pasl nine or ten years. The editors are practitioners of established reputation, and the list of contributors embraces many ofthe most eminent professors and teachers of London, Edinburgh, Dublin, and Glasgow. It is, indeed, the great merit of this work that the principal articles have been furnished by practitioners who have not only devoted especial attention to the diseases about which they have written, but have also enjoyed opportunities for an extensive practical acquaintance with them.—and whose reputation carries the assurance of their competency justly to appreciate the opinions of others, while it stamps their own doctrines with high and just authority.—American Medical Journal. WILLIAMS ON RESPIRATORY ORGANS. A PRACTICAL TREATISE ON DISEASES OF THE RESPIRATORY ORGANS. INCLUDING DISEASES OF THE LARYNX, TRACHEA, LUNGS, AND PLEURA, BY CHARLES J. B. WILLIAMS, M. D., &c. WITH NUMEROUS ADDITIONS AND NOTES, BY MEREDITH CLYMER, M. D. With wood-cuts. In one octavo volume, with 508 pages. BENEDICT'S CHAPMAN.—Compendium of Chapman's Lectures on the Practice of Medicine. One neat volume, 8vo., pp. 25S. BUDD ON THE LIVER.—On Diseases of the Liver. In one very neat 8vo. vol., with colored plates and wood-cuts, pp. 392. CHAPMAN'S LECTURES.—Lectures on Fevers, Dropsy, Gout, Rheumatism, &c. &c. In one neat Svo. volume, pp. 450. ESQU1ROL ON INSANITY.—Mental Maladies, considered in relation to Medicine, Hygiene, and Medical Jurisprudence. Translated by E. K. Hunt, M. D., &c. In one 8vo. volume, pp. 496. THOMSON ON THE SICK ROOM.—Domestic management of the s^ck Room, necessary in aid of Medical Treatment for the cure of Diseases. Edited by R. E. Griffith, M. D. In one large royal 12ino. volume, with wood-cuts, pp. 360. HOPE ON THE HEART.—A Treatise on the Diseases of the Heart and Great Vessels. Edited by Pen- nock. In one volume, 8vo., with plates, pp. 572. LAILEMAND ON SPERMATORRHOEA.—Tbe Causes, Symptoms, and Treatment of Spermatorrhoea. Translated and Edited by Henry J. McDougal. In one volume, Svo.( pp. 320. PROUT ON THE STOMACH.—On the Nature and Treatment of Stomach and Renal Diseases. Inone volume, Svo., with colored plates, pp. 466. PHILIP ON INDIGESTION—A Treatise on Protracted Indigestion. In one volume, Svo., pp. 240. PHILIPS ON SCROFULA.—Scrofula: its Nature, its prevalence, its Causes, and the Principles of its Treatment. In one volume, Svo., with a plate, pp. 350. WHITEHEAD ON ABORTION, &c—The Causes and Treatment of Abortion and Sterility: being the Result of an Extended Practical Inquiry into the Physiological and Morbid Conditions of the Ulerus. In one volume, Svo., pp. 368. RFNNET ON THE UTERUS.—A Practical Treatise on Inflammation, Ulceration, and Induration of the Neck ofthe Uterus. In one small 12mo. volume, pp. 146. 14 LEA &, BLANCHARD'S PUBLICATIONS —(Materia Medica, &c.) ILLUSTRATED ENCYCLOPEDIA OF MATERIA MEDICA. IHE ELEMENTS OF MATERIA MEDICA AND THERAPEUTICS. COMPREHENDING THE NATURAL HISTORY, PREPARATION, PROPERTIES, COMPOSITION, EFFECTS, AND USES OF MEDICINES, BY JONATHAN PEREIRA, M. D., F. R. S. and L. S., Member ofthe Society of Pharmacy at Paris; Examiner in Materia Medica and Pharmacy in the University of London ; Lecturer on Materia Medica at the London Hospital. &c. &c. Second American Edition, Enlarged and Improved. WITH NOTES AND ADDITIONS, BY JOSEPH CARSON, M. D. In two volumes octavo, containing Fifteen Hundred very large pages, illustrated by Two hundred and Seventy five Woodcuts. Notwithstanding the large size of this work, and the immense quantity of matter contained in ita closely printed pages, it is offered at a price so low as to place it within the reach of all. An Encyclopaedia of knowledge in that department of medical science—by the common consent ofthe pro- fession ihe most elaborate and scientific Treatise on Materia Medica in our language.— Western Journal of Medicine and Surgery. This Encyclopaedia of Materia Medica, for such it may justly be entitled, gives the fullest and most ample exposition of Materia Medica and its associate branches of any work heretofore published in the English lan- guage.— JV. Y. Journal of Medicine. The work will be found an invaluable storehouse of information for the physician and medical teacher, and we congratulate the profession of ihis country that it is now placed within their reach.— Amer. Med. Journal. An authoritative and unerring pharmacological guide.—Medical Examiner. Any quotations from a work so well known as this, and which has deservedly become one of the highest authority in the department of medical science to which it relates, would be superfluous. The untiring in- duslry ofthe author, and his extensive researches into the medical literature of every country, are impressed upon the mind ofthe reader in each page of the volume. Not a fact of any importance, bearing directly or indirectly upon his subject, is allowed by the author to escape. All are chronicled with accuracy and order; and, instead ofthe dry hisiory of a drug, the reader finds himself instructed in philology, natural history, bota- ny, physiology, or chemistry, so that he can seldom refer for informaiion on one point without acquiring some knowledge on others which had hitherto escaped his notice. This work shows that Dr. Pereira is not only an extensive reader, but a practical man. He has studiously endeavored to bring the present edition up to the scientific level of the day, and in this we need hardly say he has succeeded.—London Med. Gazette. Beyond dispute, the best work on Materia Medica.—Lancet, April, 1849. The work will be found an invaluable storehouse of information for the physician and medical teacher, and we congratulate the profession of this country that it is now placed within their reach.—Amer. Med. Journal. ELLIS'S MEDICAL FORMULARY. Improved Edition. Now Ready. 1849. THE MEDICAL" FORMULARY: BEING A COLLECTION OF PRESCRIPTIONS, DERIVED FRO VI THE WRITINGS AND PRACTICE OF MANY OF THE MOST EMINENT PHYSICIANS OF AMERICA AND EUROPE. TO WHICH IS ADDED AN APPENDIX, CONTAINING THE USUAL DIETETIC PREPARATIONS AND ANTIDOTES TOR POISONS. THE WHOLE ACCOMPANIED WITH A FEW BRIEF PHARMACEUTIC AND MEDICAL OBSERVATIONS. BY BENJAMIN ELLIS, M. D., NINTH EDITION, CORRECTED AND EXTENDED, BY SAMUEL GEORGE MORTON, M.D. In one neat octavo volume, of 268 pages. In preparing the new edition of this popular and valuable work, great care has been taken to bring it up to the advanced science ofthe day. The size of the page has been increased, thus enlarging the work without exlending its bulk, while the price is kept at the former rate. A chapter has been added on Ether and Chlo- roform, the subject of poisons has been rewritten and enlarged, and many new formulas interspersed through- out the volume. # ° DUNGLISON ON NEW REMEDIES. NEW EDITION. NEW REMEDIES, BY ROBLEY DUNGLISON, M. D., &c. &o. Fifth edition, with extensive additions. In one neat Octavo volume. A work like this is obviously not suitable for either critical or analytical review. It is, so far as it goes, a dispensatory, in which an account is given ofthe chemical and physical properties of all the articles recently added to the Materia Medica and their preparations, with a notice ofthe diseases for which they are pre- scribed, the doses, mode of administration, Sec—The Medical Examiner. LEA. & BLANCHARD'S PUBLICATIONS.—(Materia Medica, rj-c.) 15 CJURISTISOJY tC GRIFFITH'S niSFEJS'S.lTORY, .Vote Ready. A DISPENSATORY, OR COMMENTARY ON THE PHARMACOPOEIAS OF GREAT BRITAIN AND THE UNITED STATES: COMPRISING THE NATURAL HISTORY, DESCRIPTION, CHEMISTRY, PHARMACY, ACTIONS, USES AND DOSES OF THE ARTICLES OF THE MATERIA MEDICA. BY ROBERT CHRISTISON, M.D., V.P.R.S.E., PRESIDENT OF THE ROYAL COLLEGE OF PHYSICIANS OF EDINBURGH, PROFESSOR OF MATERIA MEDICA IN THE UNIVERSITY OF EDINBURGH, ETC. Second Edition, Revised and Improved, WITH A SUPPLEMENT CONTAINING THE MOST IMPORTANT NEW REMEDIES. WITH COPIOUS ADDITIONS, AND TWO HUNDRED AND THIRTEEN LARGE WOOD ENGRAVINGS, BY R. EGLESFELD GRIFFITH, M.D., AUTHOR OF "A MEDICAL BOTANY," ETC. In One very large and handsome Octavo Volume of over One Thousand closely printed Pages, with numerous Wood-cuts, beautifully printed, on fine white paper. Presenting an immense quantity of matter at an unusually low price. It is enough to say that it appears to us as perfect as a Dispensatory, in the present state of pharmaceuti- eal science, could be made. If it omits any details pertaining to this branch of knowledge which the student has aright to expect in such a work, we confess ihe omission has escaped our scrutiny. We cordially recommend this work to such of our readers as are in need of a Dispensatory. They cannot make choice of a hetter.— The Western Journal of Medicine and Surgery. In conclusion, we need scarcely say that we strongly recommend this work to all classes of our readers. As a Dispensatory and commentary on the Pharmacopoeias, it is unrivalled in the English or any other lan- guage.— The Dublin Quarterly Journal. We earnestly recommend Dr. Chrislison'S Dispensatory to all our readers, as an indispensable companion, not in the Study only, but in the Surgery also.—British and Foreign Medical Review. It is exactly the work we would give to the student for daily reading, or to the practitioner for regular refer- ence. Without being encumbered with unnecessary detail or research, it is sufficiently explicit in its litera- ture to render it an ample encyclopaedia of iis subject; and at the same time, its practical information is so condensed and summary, yet without a sacrifice of even the least important fact, that to the student it cannot but be a text-book invaluable in its kind. Had we said less concerning this volume we should have been wanting in common duty ; hut it is not necessary that we should say more to convince our readers that we consider it to be the best English work extant upon the subject it embraces.—Medical Times. There is not in any language a more complete and perfect Treatise.—N. Y. Annalist. As nearly complete as possible- a work of great authority and usefulness.— Charleston Medical Journal. One of the standards of the day, and as such must meet the favor it deserves.—Am. Jour, of the Med. Sciences. In advance of most that has been written on the subject — Buffalo Medical Journal. As perfect as such an undertaking can well be—Southern Medical and Surgical Journal. We can heartily recommend this work as one of ihe very best of its kind.—Northwestern Medical Journal. It should occupy a conspicuous place in the bureau of every physician and apothecary .—N. O. Medical and Surgical Journal. ,,,.., j t.j- The most accurate, the best arranged, and the cheapest work of the kind.—London and Edinburgh Jour- nal of Medical Science. . . . To those who do not possess Wood Sf Bache, we would say procure Christison c.) ROYLE'S MATERIA MEDICA. MATERIA MEDICA AND THERAPEUTICS; INCLUDING the Preparations of the Pharmacopoeias of London, Edinburgh, Dnblin, and of the United States. WITH MANY NEW MEDICINES. BY J. FORBES ROYLE, M. D., F. R. S., Professor of Materia Medica and Therapeutics, King's College, London, &c. &c. EDITED BY JOSEPH CARSON, M. D., Professor of Materia Medica in the Philadelphia College of Pharmacy, &c. &c. WITH NINETY-EIGHT ILLUSTRATIONS. In one large octavo volume, of about Seven Hundred Pages. Being one of the most beautiful Medical works published in this Country. This work is, indeed, a most valuable one, and will fill up an important vacancy that existed between Dr. Pereira's most learned and complete system of Materia Medica, and the class of productions on the other ex- treme, which are necessarily imperfect from their small extent.—British and Foreign Medical Review. Of the various works on the plan of the one before us, there is none more deserving of commendation. Every one who can afford it, should possess this excellent work.—Medical Examiner. We cannot too highly recommend this valuable work, both to the student and practitioner.— Southern Jour- nal of Medicine and Pharmacy This work is ably done—the botanical part with great skill; and the chemical, natural history, and thera- peutic department most perfect and complete.—Edinburgh Medical Journal. The subject is well treated, the matter practical and well arranged, and we do not hesitate to recommend it as a most useful volume to the student and practitioner.—Medical Gazette. The wood engravings by which the crystals, the vegetable products, and the medicinal animals are illus- trated, are better than anything hitherto attempted in Materia Medica, and must prove a great assistance to the student, appealing as they do more powerfully to the mind than the most careful verbal descriptions taken alone could do.—Lancet. Each substance is considered in reference to its history, its physical and chemical properties, preparations, tests, action, uses, and doses. All of these are briefly sketched in a concise and lucid manner, and in a way lo show that a master-hand was employed in the task.—JV. O. Medical and Surgical Journal. JYEW _/.V/J COMPLETE MEIHC.il, BOTAJVY. Lately Published. MEDICAL-BOTANY, OR, A DESCRIPTION OF ALL THE MORE IMPORTANT PLANTS USED IN MEDICINE, AND OF THEIR PROPERTIES, USES, AND MODES OF ADMINISTRATION. BY R. EGLESFELD GRIFFITH, M. D., &c. &c. In one large octavo volume, of 704 pages, handsomely printed, with nearly three hundred and fifty illustrations on wood. By far the most comprehensive and complete work upon »he subject which has been issued from the Ame- rican press, filling a great vacancy in themedieal literature ofthe country.— III. 8f Ind. Med. and Surg. Jour. An admirable work.—Boston Medical and Surgical Journal. One of the greatest acquisitions to American medical literature. It should by all means be introduced at the very earliest period, into our medical schools, and occupy a place in the library of every physician in the land.— Southwestern Medical Advocate. Admirably calculated for the physician and student—we have seen no work which promises greater ad- vantages to the profession —N. O. Medical and Surgical Journal. One ofthe few books which supply a positive deficiency in our medical literature.— Western Lancet. We hope the day is not distant when this work will not only be a text-book in every medical school and college in the Union, but find a place in the library of every private practitioner.—JV. Y. Jour, of Medicine. GRIFFITH'S UNIVERSAL FORMULARY.—Nearly Ready. THE UNIVERSAL FORMULARY; A SYNOPSIS OF THE PHARMACOPOEIAS, DISPENSATORIES, AND FORMULARIES OF EUROPE AND AMERICA. "With numerous Magisterial Formulas from various sources. BY R. E. GRIFFITH, M. D., &c. &c, Author of " Medical Botany," &c. &c. In one octavo volume. This work is intended to embrace all that is of practical importance in the numerous Pharmacopoeias, Form- ularies, and Dispensatories of Europe and of this country, as well as such formulas as appeared deserving of notice in the Medical Journals, Treatises of Medicine, &c. &c, together with many others derived from pri- vate sources, which have never been hitherto published. It therefore includes all that is really useful in Redwood's Edition of Gray's Supplement to the Pharmacopoeias, in Jourdan's Pharmacopoeia, and the several works of Ellis, Fee, Paris, Thomson, Beasley, Cottereau, Cooley, Bouchardat, &c. As, in accordance with its title of a Universal Formulary, it will not be confined solely to medical formulas, the publishers hope that the numerous scientific receipts embraced, will render it of much practical importance to the Chemist and Manufacturer. It will contain UPWARDS OF SIX THOUSAND FORMULAS, alphabetically arranged, with copious indexes, pointing out the diseases in which the preparations are to be used, &c. &c, and thus combining the advantages of all the different modes of arrangement and reference. LEA & BLANCHARD'S PUBLICATIONS .—(Materia Medica, £c.) 17 Mohr, Redwood, and Procter's Pharmacy. Just Issued. practical"pharmacy. COMPRISING THE ARRANGEMENTS, APPARATUS, AND MANIPULATIONS OF THE PHARMACEUTICAL SHOP AND LABORATORY. BY FRANCIS MOHR, Ph.D., Assessor Pharmacia? of the Royal Prussian College of Medicine, Coblentz. AND THEOPHILUS REDWOOD, Professor of Pharmacy in the Pharmaceutical Society of Great Britain. EDITED, WITH EXTENSIVE ADDITIONS, BY PROF. WM. PROCTER, Jr., Of the Philadelphia College of Pharmacy. In One handsomely printed Octavo Volume, of Five Hundred and Seventy Pages, with over 500 beautiful Engravings on Wood. In presenting the work of Mohr and Redwood to the American Pharmaceutical public, it is tin- der the impression that the want of a treatise on the apparatus and manipulations of Practical Phar- macy has long been felt. The Practice of Pharmacy, as conducted in England and in the United States, is sufficiently alike to render this work appropriate as a handbook for the American Apoth- ecary ; and the eminence ofthe authors in their respective countries, is a guarantee ofthe value of the information it contains. In passing through the hands of the Editor, the book has been increased more than one-fourth in size, about one hundred wood-cuts have been added, the arrangement ofthe subjects materially changed, and the work divided into chapters, each of which includes either one distinct subject, or several that have a certain generic relation to each other. One subject sought by the change of arrangement has been to fit the work as a text-book for the Editor's class in the Philadelphia College of Pharmacy, as far as its nature will admit, and some of the additions have been made with a view to the same object.—Editor's Preface. After a careful examination of this treatise, we have no hesitation in giving it our strongest recommenda- tion, as excellent both in matter and manner. The whole of it is marked by a clear sense of the objects to be gained, by ingenuity in devising means for their accomplishment, and by a facility in explanation which ren- ders every description at once intelligible. The wood engravings are of first-rate execution, and are so pro- fusely scattered through ihe volume as to leave nothing lo be desired in the way of illustration. As we do not address ourselves to the mere pharmaceutist, we shall not speak ofthe special adaptation of the work to his wants; but shall simply say that every medical practitioner who has anything to do with chemical pro- cesses, whether in the study of chemical pathology, or in the preparation and dispensing of medicines, will find in it a number of valuable hints, conducive alike to the saving of labor, and to the more effectual perform- ance of his operations. It furnishes the results of a much more extensive practical acquaintance with the subject, than our professional writers on Materia Medica and Pharmacology can be expected to possess.— The British and Foreign Medico-Chirurgical Review. The work is original in its design, and complete in its execution. The most minute details are described with great accuracy; and ihe illustrations are so well executed and so numerous, that a cursory inspection ofthe work is sufficient to convince the reader of its great practical utility. It is a kind of work for which there has long been a demand in this country, comprising a very complete account of all pharmaceutical operations, with the various modes of conducting them, as well as the apparatus.— Pharmaceutical Journal. It is in all respects well qualified for the purpose proposed. It presents, in a sensible and judicious fotm, all the requisite information as .to the detailsof conducting the businessof chemist, druggist, and apothecary, and will be found a most useful and indispensable guide in the laboratory and manufactory. The volume is alto- gether one of great and indispensable utility to the druggist and compounder, and a most useful guide to all branches ofthe profession. It is illustrated with most beautiful and correct wood-cut figures of the various sorts of apparatus.— The Edinburgh Medical and Surgical Journal. From Prof. Lewis C. Beck, ofthe Albany Medical College. It is a capital book, and ought to be in the handsof every apothecary in the country. I shall strongly recom- mend it to my class in the Albany Medical College. DISPENSATORY AND FORMULARY. A DISPENSATORY AND THERAPEUTICAL REMEMBRANCER. COMPRISING THE ENTIRE LISTS OF MATERIA MEDICA, With every Practical Formula contained in the three British Pharmacopeias. WITH RELATIVE TABLES SUBJOINED, ILLUSTRATED BY OTWARDS OF SIX HUNDRED AND SIXTY EXAMPLES. The Extemporaneous Forms and Combinations suitable for the different Medicines. BY JOHN MAYNE, M. D., L. R. C. S., Edin., &c. &c. EDITED, WITH THE ADDITION OF THE FORMULA OF THE UNITED STATES PHARMACOPEIA, BY R. EGLESFELD GRIFFITH, M. D., In one 12mo. volume, of over three hundred large pages. The neat typography, convenient size, and low price of this volume, recommends it especially to physicians, apothecaries, and students in want of a pocket manual. NOW READY. THE THREE KINDS OF COD-LIVER OIL, Comparatively considered, with their Chemical and Therapeutic Properties, BY L. J. DE JONGH, M. D. TRANSLATED, WITH AN APPENDIX AND CASES, BY EDWARD CAREY, M. D. To which is added, an article on the subject from "Dunglison on New Remedies." In one small 12mo. volume, extra cloth. 18 LEA &, BLANCHARD'S PUBLICATIONS.—(Midwifery., MEIGS' OBSTETRICS. —Now Ready. OBSTETRICS: THE SCIENCE AND THE ART. BY CHARLES D. MEIGS, M.D. Professor of Midwifery and the Diseases of Women and Children in the Jefferson Medical College, Philadelphia, &c. &c. With One Hundred and Twenty Illustrations. In One beautifully printed Octavo Volume, of Six Hundred and Eighty Large Pages. Treatise after treatise on the theory and practice of Midwifery have, within a few years past, issued from the press in rapid succession, each excellent in its kind, and ihe majonly bearing the names of the most diligent cultivators, and distinguished practitioners of obstetricy. Amid ihese, the work of Dr. Meigs will claim a high and commanding position. As an elementary treatise—concise, but. withal, clear and compre- hensive—we know of no one belter adapted for the use ofthe student; while the young practitioner will find in it a body of sound doctrine, and a series of excellent practical directions, adapted to all the condi- tions of the various forms of labor and their results, which he will be induced, we are persuaded, again and again to consult, and always with profit. The work of Dr. Meigs bears all the intrinsic marks of being the production of one who has not only had ample opportunities for studying the several subjects of which he treats, but who has carefully improved those opportunities. There is an earnestness in ihe author's style, as of one having authority. What he de- scribes, he has evidently seen—what he directs to be done, he has himself practised. From his very manner of teaching, we perceive that the obstetric science he inculcates has been deduced from, or verified by his own observations, and that the correctness of the rules of practice laid down by hirn has been tested by his own experience. This, while it constitutes in a great degree the value of the work, in relation lo every point connected with the science and the art of obstetrics, renders it likewise a more pleasing one to siudy. The reader seems rather to be listening to the earnest, truthful, and living voice of one qualified to teach, than merely perusing the dry details of doctrine and of practice from the primed pages of a book. It has seldom been our lot to peruse a work upon the subject, from which we have received greater satis- faction, and which we believe to be better calculated to communicate to the student correct and definite views upon the several topics embraced within the scope of its teachings. It is unnecessary for us to recom- mend the work to the favorable notice ofthe profession; before even our remarks shall reach them, the work, we are persuaded, will be in the hands ofthe major portion of American physicians, as well as of those who are destined shortly to become such.—American Journal of the Medical Sciences, April 1S49. Elsewhere we shall look for an elaborate review of this work—we refer to it now merely to welcome its appearance, and lo assure the student, who may be about to purchase a midwifery, thai we are acquainted with none of greater practical value.—Boston Medical and Surgical Journal. The very minuteness and particularity alluded to by the author constitute one. ofthe strong and commend- able features of the work, not for the student only, but for practitioners of all grades of experience. We most sincerely recommend it, both to the student and practitioner, as a more complete and valuable work on the Science and Art of Midwifery, than any of the numerous reprints and American Editions of European works on the same subject.—N. Y. Annalist, April 1S49. The above work will be welcomed most cordially by all who feel an interest in the study of obstetrics. Its author is well known as a practitioner of vast experience, in matters appertaining lo midwifery, and the diseases of women and children, and it is truly surprising how one, who is continually going about doing good in his way, should find time to write so much and so well as does Dr. Meigs. In conclusion, we would recommend this treatise on obstetrics to the profession as one worthy the reputa- tion of its distinguished author.—Medical Examiner, May 1849. TYLER SMITH ON PARTURITION.—A Mew Work.—Just Ready. ON PARTUKIT10N AND THE PRINCIPLES AND PRACTICE OF OBSTETRICS. Br W. TYLER SMITH, M.D. Lecturer on Obstetrics in the Hunterian School of Medicine, &c. &c. In one large duodecimo volume, of 400 pages. The work will recommend itself by its intrinsic merit to every member of the profession. Lancet, April 1849. We can imagine the pleasure with which William Hunter or Denman would have welcomed the present work; certainly the most valuable contribution lo obstetrics that has been made since their own day For ourselves we consider its appearance as the dawn of a new era in this department of medicine. We have thus givena brief, but we believe accurate and succinct, outline of the original views contained ia this volume. At every page of the work itself, practical deductions are drawn from Ihe physiological doctrines as they are advanced; but we have for the present chiefly confined ourselves to the latter In a future bibliographical sketch we shall, with equal care, go over these lectures, which are entirely devoted to practical points; and we are sure that the interest of our readers will not flag while they follow us in our lask. We would observe, that we do not pledge ourselves to all and every doctrine promulgated by Dr Tyler Smith. This would be impossible, considering the magnitude of the subject itself, and the great vari- ety and importance of the topics discussed; but we do most cordially recommend the work as one absolutely necessary to be 6tudied by every accoucheur. It will, we may add, prove equally interesting and instructive to the student, the general practitioner, and pure obstetrician." It was a bold undertaking to reclaim parturi- tion, for Reflex Physiology, and it has been well performed.—London Journal of Medicine. LEA & BLANCHARD'S PUBLICATIONS.—(Midwifery.) 19 NEW EDITION, NOW READY. THE PRINCIPLES AND PRACTICE OP OBSTETRIC MEDICINE AND SURGERY, In reference to the Process of Parturition. BY FRANCIS H. RAMSBOTHAM, M.D. Physician to the Royal Maternity Charity, &c. &c. FIFTH AMERICAN FROM THE LAST LONDON EDITION. Illustrated with One Hundred and Forty-eight Figures on Fifty-five Lithographic Plates. In one large and handsomely printed volume, imperial octavo, with 520 pages. From Professor Hodge, ofthe University of Pennsylvania. To the American public, it is most valuable, from its intrinsic undoubted excellence, and as being the best authorized exponent of British Midwifery. Its circulation will, I trust, be extensive throughout our country. We recommend the student, who desires to master this difficult subject with the least possible trouble, to possess himself at once of a copy of this work.—American Journal of the Medical Sciences. It stands at the head of ihe long list of excellent obstetric works published in the last few years in Great Britain, Ireland, and the Continent of Europe We consider this book indispensable to the library of every physician engaged in the practice of Midwifery.—Southern Medical and Surgical Journal When the whole profession is thus unanimous in placing such a work in the very first rank as regards the extent and correctness of all the details of ihe theory and practice of so important a branch of learning, our commendation or condemnation would be of little consequence; but, regarding it as the most useful of all works ofthe kind, we think it but an act of justice to urge its claims upon the profession— JV. O. Med. Journal. We are disposed to place it first on the list of the numerous publications that have appeared on this subject; for there is none within our knowledge that displays in so clear and forcible a manner every step in the pro- cess, and that, too, under all imaginable circumstances.—JV. Y. Journal of Medicine. New Edition. Revised for this Country. THEORY AND PRACTICE OF MIDWIFERY. BY FLEETWOOD CHURCHILL, M. D., Hon. Fellow ofthe Royal College of Physicians of Ireland, &c. &c. WITH NOTES AND ADDITIONS BY ROBERT M. HUSTON, M. D., &c. THIRD AMERICAN EDITION, REVISED AND IMPROVED BY THE AUTHOR. With One Hundred and Twenty-eight Illustrations, In One very handsome Octavo Volume, of Five Hundred and Twenty-Six Pages. This is certainly the most perfect system extant. It is the best adapted for the purposes of a text-book, and that which he whose necessities confine him to one book, should select in preforence to all others.—Southern Medical and Surgical Journal. The most popular work on Midwifery ever issued from the American press —Charleston Medical Journal. Certainly, in our opinion, the very best work on the subject which exists.—N. Y. Annalist. Were we reduced to the necessity of having but one work on Midwifery, and permitted to choose, we would unhesitatingly take Churchill.— Western Medical and Surgical Journal. It is impossible to conceive a more useful and elegant Manual than Dr. Churchill's Practice of Midwifery. — Provincial Medical Journal. No work holds a higher position, or is more deserving of being placed in the hands of the tyro, the advanced student, or the practitioner.—Medical Examiner. LEE'S CLINICAL MIDWIFERY. Now Ready. CLINICAL MIDWIFERY, COMPRISING THE HISTORIES OF FIVE HUNDRED AND FORTY-FIVE CASES OF DIFFI- CULT, PRETERNATURAL, AND COMPLICATED LABOR, WITH COMMENTARIES. BY ROBERT LEE, M.D., F.R. S., &c. From the 2d London Edition. In one royal 12mo. vol., extra cloth. 238 pages. More instructive to the juvenile practitioner than a score of systematic works.—Lancet. Will be consulted by every accoucheur who practices his art with the zeal which it merits.—Med. Gazette. An invaluable record for the practitioner— N. Y. Annalist. This admirable book of precedents.—Boston Medical and Surgical Journal. A storehouse of valuable facts and precedents.—American Journal ofthe Medical Sciences. DEWEES'S MIDWIFERY. A COMPREHENSIVE SYSTEM OF MIDWIFERY. ILLUSTRATED BY OCCASIONAL CASES AND MANY ENGRAVINGS. BY WILLIAM P. DEWEES, M. D., Tenth Edition with the Author's last Improvements and Corrections. In one Octavo Volume, of 660 page* 20 LEA & BLANCHARD'S PUBLICATIONS.—(Diseasesof Women and Children.) JUE1GS OSS" FEMALES. FEMALES AND THEIR DISEASES; A SERIES OF LETTERS TO HIS CLASS. BY C. D. MEIGS, M. D., Professor of Midwifery and the Diseases of Women and Children in the Jefferson Medical College of Philadelphia, &c. &c. In One large and beautifully printed Octavo Volume of 670 Pages. He has evidently seen almost every form and variety of female disease, and not only seen, but observed and reflected, and if we may judge by the innate evidence afforded by the volume itself, practised success- fully. His volume contains many practical hints and suggestions which will repay perusal.— The Charleston Medical Journal and Review. The work is written in a free, animated conversational style, and is replete with sound practical instruc- tion.— The Western Lancet. We warmly commend the work of Professor Meigs as a highly interesting and instructive volume.—N. Y. Journal of Medicine. The work contains a very large fund of valuable matter,and will, in all probability, become avery popular one.—American Medical Journal. His great reputation, the change in the book from the usual manner of writing, and the intrinsic merits with which the work abounds, will give it a wide-spread circulation, and a very general perusal.— Northern and Western Medical and Surgical Journal. The style is certainly not faultless, but yet it is one which, we venture to believe, will prove acceptable to most of the readers to whom it is especially addressed. It is fresh, buoyant, varied and sprightly, and one is carried along by it without weariness They are full of instruction. It would be difficult lo point to a vol- ume containing more valuable information relative to females and their diseases.— I'he Western Journal of Medicine and Surgery. We feel that in ihis hasty sketch we have given the reader scarcely an idea of the vast amount of useful information which the book contains, and ofthe pleasing style in which, generally, it is conveyed, and most conscientiously advise him to purchase and read it for himself. It is, nevertheless, one of the most original and pleasant medical books, and one of the most agreeable upon the subject, we have ever read ; and we cannot but acknowledge, that Professor JVIeigs has rendered by its publication a great service to his profes- sion, and done great credit to his own industry and scholarship, and to his skill as a practitioner, and his ability as a teacher.— The Annalist. The body of the book is worthy of extensive consideration, and is evidently the production of a clever, thoughtful, and sagacious physician. Dr. Meigs' letterson the diseasesof the external organs, contain many interesting and rare cases, and many instructive observations. We take our leave of Dr. Meigs, with a high opinion of his talents and originality.— The British and Foreign Medico-Chirurgical Review. Every chapter is replete with practical instruction, and bears the impress of being the composition of an acute and experienced mind. There is a terseness, and at the same time an accuracy, in his description of symptoms, and in the rules for diagnosis, which cannot fail to recommend the volume to the attention of the reader.—Ranking's Abstract. ASHWELL ON THE DISEASES OF FEMALES." A PRACTICAL TREATISE ON THE DISEASES PECULIAR TO WOMEN, Illustrated by Cases derived from Hospital and Private Practice. BY SAMUEL ASHWELL, M. D., Member ofthe Royal College of Physicians; Obstetric Physician and Lecturer to Guy's Hospital, &c. WITH ADDITIONS, BY PAUL BECK GODDABD, M. D., SECOND AMERICAN EDITION. In one octavo volume of Five Hundred and Twenty Pages. One ofthe very best works ever issued from the press on the Diseases of Females.— Western Lancet. This invaluable work.—Missouri Medical and Surgical Journal. "We strongly recommend Dr. Ashwell's Treatise to our readers as a valuable book of reference, on an ex- tensive, complicated, and highly important class of diseases.—Edinburgh Monthly Journal of Med. Sciences. ATREATISE ON THE DISEASES OF FEMALES. BY W. P. DEWEES, M. D. NINTH EDITION. In one volume, Svo. 532 pages, with plates. A TREATISE ON THE PHYSICAL AND MEDICAL TREATMENT OF CHILDREN BY W. P. DEWEES, M. D. NINTH EDITION. In one volume, 8vo. 548 pages. SECOND E DIT10 N.-Now Ready. 1850. MEIGS' TRANSLATION OF A Treatise on the Diseases of Females, and on the Special Hygiene of their Sex. BY COLOMBAT DE L'ISERE, M. D., &c. Second edition, revised. In one large octavo volume, of 720 pages. Many wood-cuts. LEA & BLANCHARD'S PUBLICATIONS.—(Diseases of Women and Children.) 21 New Edition, brought up to 1850. Now Ready. A PRACTICAL TREATISE ON THE DISEASES OF CHILDREN. BY D. FRANCIS CONDIE, M. D., Fellow ofthe College of Physicians; Member of the American Philosophical Society, &c. Third Edition, Revised and Improved. In One large Octavo Volume, of nearly 700 Pages. We feel persuaded that the American Medical profession will soon regard it. not only as a very good, but as the very best '• Practical Treatise on the Diseases of Children."— American Medical Journal. We pronounced the first edition to be the best work on the Diseases of Children in the English language, and, notwithstanding all that has been published, we still regard it in that light.—Medical Examiner. . . From Professor D. Humphreys Storer, of Boston. I consider it to be the best work on the Diseases of Children we have access to, and as such recommend it to all who ever refer to the subject. . From Professor M. M. Fallen, of St Louis. I consider it the best treatise on the Diseasesof Children that we possess, and as such have been in the habit of recommending it to my classes. Dr. Condie's scholarship, acumen, industry, and practical sense are manifested in this, as in all his nu- merous contributions lo science.—Dr. Holmes's Report to the American Medical Association. Taken as a whole, in our judgment, Dr. Condie's Treatise is the one from the perusal of which the practi- tioner in this country will rise with the greatest satisfaction.— Western Journal of Medicine and Surgery. One ofthe best works upon the Diseases of Children in the English language.— Western Lancet. CHURCHILL, OJ>r FEMALES. THE DISEASES~OF FEMALES, INCLUDING THOSE OF PREGNANCY AND CHILDBED. BY FLEETWOOD CHURCHILL, M. D., Author of Theory and Practice of Midwifery, &c. &c. FOURTH AMERICAN, FROM THE SECOND LONDON EDITION, WITH ILLUSTRATIONS, EDITED, WITH NOTES, BY ROBERT M. HUSTON, M. D., &c. &c. In one octavo volume of 604 pages. The rapid sale of three editions of this valuable work, stamp it so emphatically with the approbation of the profession of this country, that the publishers in presenting a fourth deem it merely necessary to observe, that every care has been laken by the editor, to supply any deficiencies which may have existed in former impressions, and to bring the work fully up to the dale of publication. One great and distinguishing irait of the volume is. that it embraces all the diseases peculiar to women, which can hardly be said of any other publication ; and it is this circumstance that especially recommends it lo practitioners who are without the opportunity of consulting numerous works.—Medical Examiner. MEIGS ON CERTAIN DISEASES OF INFANTS. In one octavo volume. Nearly ready. Now Ready.—CHURCHILL ON CHILDREN. ON THE DISEASES OF INFANTS AND CHILDHOOD. BY FLEETWOOD CHURCHILL, M. D., M. R. I. A. Author of'Theory and Practice of Midwifery," "Diseases of Females," &c. In one large and handsome octavo volume of six hundred pages. The author's desire to render this work a complete and accurate text-book, has caused the delay which has taken place in its appearance. This has rendered it unnecessary to have recourse to the servicesof an editor for this country, but the publishers have caused the sheets to be submitted to a professional gentleman, that no inaccuracy should occur in its passage through the press iri this country. As the book has been pre- pared by the author with a special reference to this country, it will be found sufficiently full with respect to all diseases peculiar to the United Slates, which the extensive reading of Dr. Churchill has enabled him to supply. __^^.^^^~v~v^~^ WEST ON CHILDREN.—Now Ready. LECTURES ON THE DISEASES OF INFANCY AND CHILDHOOD. BY CHARLES WEST, M. D. In one octavo volume of four hundred and fifty pages. r , • i „ „„fn, weot w^ pan scareelv do more than reiterate our former praise of him. We have dvent ffelra,VbutaDvrer7fa nt notion oMhe Icoperf his work, and of its excellent execution. It is one given, we ear, oui a ye y subject in our language-unapproached-unrivalled His knowledge ot standing by itself g W™™ • ' his OWI1 expensive experience ; and the results of both are com- ffidTn hi" viable"'pracTallecture, now offered for the guidance of others. It will be long before it finds a rival in this <;ou"'rm- . excu„ed if we say to the student and junior practitioner, let the pathology of In conclusion, we may Deexcu , pathology, be your earnest study for the future, and let CourreuidebeZ'lectures o?i?.WeT-The British and Foreign Medico-Chirurgical Review. 22 LEA & BLANCHARD'S PUBLICATIONS.— (Surgery.) "theTgreat surgTcalTIlibr ary. A SYSTEM OF SURGERY, BY J. M. CHELIUS, Doctor of Medicine and Surgery, Public Professor of General and Ophthalmic Surgery, &c. &c, in the University of Heidelberg. TRANSLATED FROM THE GERMAN, AND ACCOMPANIED WITH ADDITIONAL NOTES AND OBSERVATIONS, BY JOHN F. SOUTH, Surgeon to St. Thomas' Hospital. Now complete in three large 8vo. vols, of nearly 2200 pages, or in seventeen numbers, at 50 cents. This great work is within itself a library of reference for the surgical practitioner. Every detail of import- ance in Minor Surgery, Operative Surgery, and the Principles of Surgery will be found embodied in it, sys- tematically arranged and clearly expressed, together with a copious Surgical Bibliography. This vast mass of information is elucidated and rendered easy of reference by an index occupying one hundred and seventy double columned pages, enabling ihe surgeon to refer at once to the opinions of ihe best authorities on any disputed point. The reputation ofthe original work is sufficiently exemplified by its having passed through six editions in Germany, and having been translated into eight languages. The translation of Mr. South was undertaken with the concurrence and assistance ofthe author, and the translator has made numerous and im- portant additions to the work, embodying the facts and opinions set forth by all the principal surgeons of Con- tinental Europe, Great Britain, and the United States. With all these advantages, it is confidently presented to the profession as the most complete system of Surgical Science in the English language. In this work, the practitioner will find the fullest and ablest digest extant of all that relates to the present ad- vanced state of Surgical Pathology.—American Medical Journal. If we were confined to a single work on Surgery, that work should be Chelius's.— St. Louis Med. Journal. As complete as any system of Surgery can well be.—Southern Medical and Surgical Journal. The mo>t extensive and complete system of Surgical practice in the English language.1—222. and Ind. Med- ical and Surgical Journal. The most finished system of Surgery in the English language.— Western Lancet. The most learned and complete systematic treatise now extant.—Edinburgh Medical Journal. No work in the English language comprises so large an amount of information relative to operative medi- cine and surgical pathology.—Medical Gazette. We have, indeed, seen no work which so nearly comes up to our idea of what such a production should be, both as a practical guide and as a work of reference, as this. It is methodical and concise, clear and accu- rate.— The New York Journal of Medicine. No work on Surgery in our language is so complete, both as regards the general plan and the minutestde- tails.— Southern Journal of Medicine and Surgery. A complete encyclopedia of surgical science—a very complete surgical library—by far the most complete and scientific system of surgery in the English language.— JV. Y. Journal of Medicine. One ofthe most complete treatises on Surgery in the English language —Monthly Journal of Med. Science. We feel gratified and proud ofthe work in its English garb, and we do not hesitate to pronounce it the best and most comprehensive system of modern Surgery with which we are acquainted, and as such we earnestly recommend it to the student and practitioner.—Medico-Chirurgical Review. It is one of the most learned and practical writings extant. It must at once take a place, wherever it is known, among the standard surgical authorities — Buffalo Medical Journal. The most extensive and comprehensive accountof the art and scienceof Surgery in our language.—Lancet. The work is closed with a most elaborate and analytical index, which occupies no less than one hundred and seventy-seven closely printed pages; this forms in itself a most valuable work of reference; and deserves to be very highly appreciated by every surgeon. We consider that this product of the combined experience and researches of Professors Chelius and South is by far the most important addition that has been made to sur- gical literature since the publication of Cooper's Surgical Dictionary.—London Medical Gazette. May be regarded as the most comprehensive work on Surgery extant.— Medical Examiner. The work may now be regarded as the most complete which exists in our language on Surgery. No work in our language is so complete, both as regards the general plan and the minutest details; and it will be an imperishable monument to Mr. South's industry, talents, and attainments. An extensive analytical index adds much to its value— Southern Journal of Medicine and Surgery. One ofthe most complete works in surgical literature.— Western Journal of Medicine and Surgery. . Members ofthe profession who reside at a distance from the metropolitan centres, and who may desire, or who, from their position may find it necessary to have a book of reference at hand, which they may regard as an authority, will derive much assistance from this work, as supplying a desideratum long wanted in the profession.—Medical Times. jyow re An jr. A TREATISE ON THE DISEASES OF THE BONES; BY EDWARD STANLEY, F. R S., In one octavo volume. RICORD ON VENEREAL. A Practical Treatise on Venereal Diseases. With a Therapeutical Summary and Special Formulary. Translated by Sidney Doane, M. D. Fourth edition. 1 vol. Svo. 340 pp. COOPER (SIR ASTLEY) ON THE ANATOMY AND TREATMENT OF ABDOMINAL HERNIA. 1 large vol., imp. 8vo., with over 130 lithographic figures. COOPER ON THE STRUCTURE AND DISEASES OF THE TESTIS, AND ON THE THYMUS GLAND. 1 vol., imp. 8vo., with 177 figures on 29 plates. COOPER ON THE ANATOMY AND DISEASES OF THE BREAST, WITH TWENTY-FIVE MISCELLANEOUS AND SURGICAL PAPERS. 1 large vol., imp. Svo., with 252 figures on 36 plates. COOPER ON DISLOCATIONS AND FRACTURES OF THE JOINTS.—Edited by Bransby Cooper and J.C.Warren. 1 vol. 8vo., with 133 cuts. 500 pp. DURLACHER ON CORNS. BUNIONS. &c—A Treatise on Corns, Bunions, the Diseases of Nails, and the General Management of the Feet. In one 12mo. volume, cloth. 134 pp. GUTHRIE ON THE BLADDER, &c.—The Anatomy of the Bladder and Urethra, and the Treatment ofthe Obstructions to which those Passages are liable. In one vol. 8vo. 150 pp. LEA & BLANCHARD'S PUBLICATIONS.—(Surgery.) 23 THE STUDENT'S TEXT-BOOK OF SURGERY. .Vew and Improved Edition. Just Issued. THE PRINCIPLES AND PRACTICE OF MODERN SURGERY, BY ROBERT DRUITT, Fellow ofthe Royal College of Surgeons. A New American from the last and improved London Edition. EDITED BY F. W. SARGENT, M. D., Author of "Minor Surgery," &c. Illustrated with One Hundred and Ninety-three Wood Engravings. In one very handsomely printed octavo volume of 576 large pages. In preparing the new edition of this popular text-book, every care has been taken so to improve it in every respect as to raise it still higher in the estimation of the profession. The edition from which this is printed has large and important additions by the author; while the present editor, Dr. Sargent, has added whatever appeared necessary to render the book a correct exponent ofthe present state of surgical science in this country. The illustrations have been entirely remodelled 5 numerous new ones added by both author and editor ; and many superior ones substituted for those rejected. The amount of these changes may be estimated from the fact, that ofthe 193 wood-cuts at present in this volume, more than one-half have appeared in no former American edition. In mechanical execution, also, the work will be found much improved; in clear type, white paper, and handsome printing, it will compare favorably with the best-executed works published in the country, while the price is still kept so low as to place it within the reach of all. An unsurpassable compendium, not only of Surgical, but of Medical Practice—London Medical Gazette. No work, in our opinion, equals it in presenting so much valuable surgical matter in so small a compass.— St. Louis Medical and Surgical Journal. The author has fully succeeded in producing a complete system of surgical science and prance in the smallest practicable compass, and at the cheapest possible price.—Edinburgh Monthly Medical Journal. It is the most accurate and ample r£sum6 ofthe present state of surgery that we are acquainted wnh .— Dublin Medical Journal. This is the best work of its size, on the subject of surgery, that has made its appearance on our desk. For the use of the general practitioner, it may be preferable to many of ihe larger works, as it has the inportant facts he wants, in a more condensed form, from which he can get his information with less labor and time, if not with clearer views ofthe subject.— The Northwestern Medical and Surgical Journal. Admirably adapted to the wants ofthe student.— Provincial Medical and Surgical Journal. A belter book on the principles and practice of surgery has not been given to the profession.—Boston Medi- cal and Surgical Journal. SARGENT'S MINOR SURGERY. A NEW WORK. ON BANDAGING, AND OTHER POINTS OF MINOR SURGERY. BY F. W. SARGENT, M. D. In one handsome volume, royal 12mo., with nearly 400 Pages, and 128 Wood-cuts. The very besi manual of Minor Surgery we have seen—Buffalo Medical and Surgical Journal. Admirably adapted lo the use of the student — Charleston Medical Journal. We can unhesitatingly recommend this volume as one of the very best of its kind.—American Med. Journal. We will adopt it as a text-book for the use of our own pupils, and we must recommend our fellow practi- tioners in all partsof the country to do likewise.— N. Y. Journal of Medicine. Nothing perhaps in the whole routine of practice redounds more decidedly to the upbuilding of a young sur- geon's reputation, and certainly none contributes more to the comfort ofthe suffering patient, than dexterity in the performance ofthe minor surgical operations, and the neat and skilful arrangement of dressings. In view of these facts, it is amatterof some degree of astonishment that a due consideration of this subject should have been deferred so long. We strongly recommend Dr. Sargent's treatise to all our readers, believing that it will prove abundantly useful to those who consult its pages for information upon the important subjects therein discussed.—The Ohio Medical and Surgical Journal. LISTON AND MUTTER'S SURGERY. LECTURES ON" THE OPERATIONS OP SURGERY, And on Diseases and Accidents requiring Operations. DELIVERED AT UNIVERSITY COLLEGE, LONDON. BY ROBERT LISTON, Esq., F. R. S.r &c. EDITED, WITH NUMEKOUS ALTERATIONS AND ADDITIONS, BY T. D. MUTTER, M. D.T &C. &C, In one large and handsome octavo volume of 566 pages, with 216 Wood-cuts, It is a compendium ofthe modern practice of Surgery as complete and accurate as any treatise of similar dimensions in the English language.— Western Lancet. LAWRENCE ON RUPTURES.—A Treatise on Ruptures, from the fifth London Edition. In one 8v©-. vol. sheep 4^0 pp. MATTRV^ DENTAL SURGERY.—A Treatise on the Dental Art, founded on Actual Experience. Illus- trated by 241'lithographic figures and 54 wood-cuts. Translated by J. B. Savier. In- 18to. vol.,sheep. 2S6pp. ROBERTSON ON THE TEETH.—A Practical Treatise on the Human Teeth, with Plates. One small volume, 8vo. 230 PP- nitPTON ON THE EAR— The Nature andTreatmentof Deafness and Diseases of the Ear; audita* Trealr mentof theDeaf and Dumb. One small 12mo. volume. 120 pp. 24 LEA & BLANCHARD'S PUBLICATIONS.—(Surgery.) FERGUSSON'S OPERATIVE SURGERY. NEW EDITION. A SYSTEM OF PRACTICAL SURGERY. BY WILLIAM FERGUSSON, F. R. S. E., Professor of Surgery in King's College, London, &c. &c. THIRD AMERICAN, FROM THE LAST ENGLISH EDITION. Willi Two Hundred and Seventy-four Illustration*, from Itraivlng-s by Itag-g, Engraved by Gilbert t> Hi lion. In one large and beautifully printed octavo volume, of six hundred and thirty pages. Ttis with unfeigned satisfaction that we call the attention ofthe profession in this country lo this excellent work. It richly deserves the reputation conceded to it, of being the best practical Surgery extant, at least in the English language.—Medical Examiner. Professor Fergusson's work, we feel persuaded, will be as great a favorite as it deserves, for it combines the powerful recommendations of cheapness and elegance, with aclear. sound, and practical treatment of every subject in surgical science. The illustrations, by Bagg, are admirable—inhis very best style—Edinburgh Journal of Medical Science. MILLER'S PRINCIPLES OF SURGERY. THE PRINCIPLES OP SURGERY. BY JAMES MILLER, F. R. S. E., Professor of Surgery in the University of Edinburgh, &c. SECOND AMERICAN EDITION, In one octavo volume of five hundred and thirty-eight pages. BY THE SAME AUTHOR. THE PRACTICE OF SURGERY. SECOND AMERICAN EDITION. In one octavo volume, of five hundred pages. These two works are printed and bound to match, forming together a complete System of Surgery. Taken together they form a very condensed and complete system of Surgery, not surpassed, as a text-book, by any work with which we are acquainted— 111. and Ind. Medical and Surgical Journal Mr. Miller has said more in a few words than any writer since the days of Celsus— JV. O. Med. and Surg, Journal. LIBRARY OF OPHTH ALM IC_M EDICI N E AND SURGERY. A TREATISE ON THE DISEASES OF THE EYE. BY W. LAWRENCE, F. R. S., Surgeon Extraordinary to the Queen, Surgeon to St. Bartholomew's Hospital, &c. &c. A NEW EDITION. With many Modifications and Additions, and the introduction of nearly two hundred Illustrations. BY ISAAC HAYS , M. D., In one very large Svo. vol. of 860 pages, with twelve plates and many wood-cuts through the text. This book contains all that is necessary for the student or practitioner to know.—Dublin Medical Press The work of Mr. Lawrence, with the numerous additions of the American Editor, is allowedly one of if not the best. The library of no medical man can be complete without it.—JV. Y. Journal of Medicine. JONES ON_THE EYE. THE PRINCIPLES AND PRACTICE OF OPHTHALMIC MEDICINE AND SURGERY. BY T. WHARTON JONES, F. R. S., &c. &c. EDITED BY ISAAC HAYS, M. D., &c. In one very neat volume, large royal 12mo. of 529 pages, with four plates, plain or colored, and ninety-eight well-executed wood-cuts. From Professor Mott, of New York. The work on Ophthalmic Surgery, by Jones, is undoubtedly ihe best on that subject in the English language. It will give me pleasure to aid in its circulation in every way in my power. Mr. Jones'Manual is a very elaborate compilation, and will, in this age of condensing, epitomizing and manualizing, doubtless occupy the foremost piace.—Medico-Chirurgical Review. BRODIE'S SURGICAL LECTURES.—ClinicalTe^tuTeToTsu^gery. 1 vol. 8vo., cloth. 350 pp. BRODIE ON THE JOINTS —Pathological and Surgical Observations on the Diseases ofthe Joints. 1 vol 8vo., cloth. 216 pp. BRODIE ON URINARY ORGANS.—Lectures on the Diseases of the Urinary Organs. 1 vol. 8vo., cloth. »#* These three works may he had neatly bound together, forming a large volume of" Brodie's Surgical Works." 7S0 pp. LEA & HLVNCHARD'S PUBLICATIONS —(Chemistry.) 25 FOWNBS' CHEMISTRY FOR STUDENTS. New and Improved Edition. ELEMENTARY CHEMISTRY, THEORETICAL AND PRACTICAL, BY GEORGE FOTTNES, Ph. D., Chemical Lecturer in the Middlesex Hospital Medical School, &c. &c. With Numerous Illustrations. Second American Edition. Edited, with Additions, BY ROBERT BRIDGES, M. D., Professor of General and Pharmaceutical Chemistry in the Philadelphia College of Pharmacy, &c. &C. In one large royal 12mo. volume, of 460 pages, sheep or extra cloth. We know of no treatise in the language so well calculated lo aid the student in becoming familiar with the numerous facls in the intrinsic science on which it treats, or one better calculated as a text-book for those at- tending Chemical lectures. * * * * The best text-book on Chemistry that has issued from our press.-^wert- can Medical Journal. We again most cheerfully recommend it as the best text-hook for students in attendance upon Chemical lectures that we have yet examined— III. and Ind. Medical and Surgical Journal. A first-rale work upon a first-rate subject.- St. Louis Medical and Surgical Journal. No manual of Chemistry which we have met, comes so near meeting the wants of the beginner.— Western Journal of Medicine and Surgery. We know of none within the same limits, which has higher claims to our confidence, as a college class- book, both for accuracy of detail and scientific arrangement.— Augusta Medical Journal. GARDNER'S MEDICAL CHEMISTRY—Now Ready. MEDICAL CHEMISTRY, FOR THE USE OF STUDENTS AND THE PROFESSION; BEING A MANUAL OF THE SCIENCE, WITH ITS APPLICATIONS TO TOXICOLOGY, PHYSIOLOGY, THERAPEUTICS, HYGIENE, &c. &c. BY D. PEREIRA GARDNER, M. D., Late Professor of Chemistry in the Philadelphia College of Medicine, &c. In one handsome royal 12oto. volume of 400 pages, with illustrations. By far the greater number of medical students will find this work of Dr. Gardner belter adapted to their wants than any other with which we are acquainted.- Ohio Medical and Surgical Journal. Admirably adapted to the end and design. We shall be much disappointed if it is not adopted as a text- book in all our American Colleges— N. Y. Journ. of Medicine. An excellent work—one likely lo be of great use to the student, and of no small value to the practitioner. —Charleston Medical Journal. ... ,. i j- ■ It is an admirable exposition ofthe facts of Chemical science in their application to practical medicine in its various branches. The work is sufficiently exiended, and very accurate in its details, and cannot fail to prove most useful as a book of study or of reference— The Lancet, March 10, lf-49. We know of no work exactly like it by any English author. The reader will find here, in a concise form, informalion for which he would otherwise have to seek in many elaborate and expensive treatises.—London Medical Gazette, March, 1849. BOWMAN'S PRACTICAL, CHEMISTRY. Now Ready. INTRODUCTION TO PRACTICAL CHEMISTRY, INCLUDING ANALYSIS. By JOHN E. BOWMAN, Demonstrator of Chemistry, King's College. In one handsome volume, royal 12mo., of over 300 pages. WITH NEARLY ONE HUNDRED ENGRAVINGS ON WOOD. One ofthe most complete manuals that has for a long time been given to the medical sluAein.-Athentrum. We ?e^a?cnt as realizing almost everything lo be desired in an introduction 10 Practical Chemistry. It n by far the bestAdapted ferine Chemical .tude'nt of any that has yet fallen ,n our way.-J?r,f«A and Foreign ^^bSKS^^ork on the .u«.ct with which we are acquainted -Edinburgh Monthly Journal, February, 1849. __^.^^ ANIMAL CHEMISTRY, WITH REFERENCE TO THE PHYSIOLOGY AND PATHOLOGY OF MAN. BY DR. J. FRANZ SIMON. TRANSLATED AND EDITED BY GEORGE E. DAY, M. A. & L. M. Cantab., &c. With plates In one octavo volume of over seven hundred pages, sheep. No treatise on Physiological Chemistry approaches this in turner and accuracy of detail.- Western Journal of Medicine and Surgery. New Edition, Preparing—THE ELEMENTS OF CHEMISTRY, " SCIENCE TO THE ARTS. WITH NUMEROUS ILLUSTRATIONS. INCLUDIN0THEBY THOMAS GRAHAM, F. R. S., L. & E. D. With Notes and Additions, by ROBERT BRIDGES, M. D., &c. &c. In one very large Svo. vol. 26 LEA & BLANCHARD'S PUBLICATIONS. TAYLOR O.V l'OISOJYS. ON POISONS, IN RELATION TO MEDICAL JURISPRUDENCE AND MEDICINE. BY ALFRED S. TAYLOR, F. R. S., &c. Edited, with Notes and Additions, BY R. E. GRIFFITH, M. D. In one large octavo volume, of 688 pages. The most elaborate work on the subject that our literature possesses.— Brit, and For. Medico- Chirur. Review. One ofthe most practical and trustworthy works on Poisons in our language.— Western Journal of Med. It contains a vast body of facts, which embrace all that is important in toxicology, all that is necessary to the guidance of the medical jurist, and all that can be desired by the lawyer.—Medico-Chirurgical Review. It is, so far as our knowledge extends, incomparably the best upon the subject; in the highest degree credit- able to the author, entirely trustworthy, and indispensable to the student and practitioner.—N. Y. Annalist. TAYLOR'S MEDICAL JURISPRUDENCE. MEDICAL JURISPRUDENCE. BY ALFRED S. TAYLOR, Lecturer on Medical Jurisprudence and Chemistry at Guy's Hospital, &c. With numerous Notes and Additions, and references to American Practice and Law. BY R. E. GRIFFITH, M. D. In one octavo volume of five hundred and forty pages. We recommend Mr. Taylor's work as the ablest, most comprehensive, and, above all, the most practically useful book which exists on the subject of legal medicine. Any man of sound judgment, who has mastered the contents of Taylor's " Medical Jurisprudence," may go into a court of law with the most perfect confi- dence of being able to acquit himself creditably.—Medico-Chirurgical Review. The most elaborate and complete work that has yet appeared. It contains an immense quantity of cases lately tried, which entitle it lo be considered what Beck was in its day.—Dublin Medical Journal. TRAILL'S MEDICAL JURISPRUDENCE—Outlines of a Course of Lectures on Medical Jurisprudence. Revised, with numerous Notes. In one small octavo volume of 234 pages. DUJYGLISOJX* OJY HUMAJY HEALTH. HUMAN "HEALTH, OR THE INFLUENCE OF ATMOSPHERE AND LOCALITY, CHANGE OF AIR AND CLIMATE\ SEASONS, FOOD, CLOTHING, BATHING, EXERCISE, SLEEP, &C &C. &C, ON HEALTHY MAN, CONSTITUTING ELEMENTS OF HYGIENE. Second Edition, with many Modifications and Additions. BY ROBLEY DUNGLISON, M. D., &c. &c. In one octavo volume of 464 pages. MITCHELL ON THE ORIGIN OF FEVERS—A New Work—Just Ready. ON THE CRYPTOGAMOUS ORIGIN OF MALARIOUS AND EPIDEMIC FEVERS. BY J. K. MITCHELL, M. D., Professor of Practical Medicine in the Jefferson Medical College of Philadelphia, &c. In one small volume of 138 pages, extra cloth. BARTLETT OJY CERTAIJYT1T IJY MEDICIJVtE—J\"bw Ready. AW INQUIRY INTO THE DEGREE OF CERTAINTY IN MEDICINE, AND INTO THE NATURE AND EXTENT OF ITS POWER OVER DISEASE. BY EI.ISHA BARTLETT, M. D„ Author of " Fevers of the United States," " Philosophy of Medical Science." In One small Volume of 84 pages, crown 8vo., extra cloth. AN ESSAY ON THE PHILOSOPHY OF MEDICAL SCIENCE. BY ELISHA BARTLETT, M. D., Author of " Fevers ofthe United States." In one handsome octavo volume of three hundred and twelve pages. A NEW EDITION OF THE MEDICAL STUDENT; Or, Aids to the Study of Medicine. A REVISED AND MODIFIED EDITION. BY ROBLEY DUNGLISON, M. D. In one neat 12mo. volume. _________ LEA AND BLANCHARD'S PUBLICATIONS. 27 MANUALS FOR EXAMINATION. Now Ready. an analyticalTcompendtum OF THE VARIOUS BRANCHES OF MEDICAL SCIENCE, FOR THE USE AND EXAMINATION OF STUDENTS. BY JOHN NEILL, M. D., DEMONSTRATOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA. LECTURER ON ANATOMY IN THE MEDICAL INSTITUTE OF PHILADELPHIA, ETC., FRANCIS GURNEY SMITH, M.D., LECTURER ON PHYSIOLOGY IN THE PHILADELPHIA ASSOCIATION FOR MEDICAL INSTRUCTION, ETC. ETC. Forming One very large and handsomely printed Volume in royal, duodecimo, of over Nine Hundred large Pages, with about Three Hundred and Fifty Wood Engravings, strongly bound in leather, with raised bands. While this work is not offered as a substitute for the regular text-books, for the purpose of study, its convenient form, and the amount of information condensed in its pages, together with the ful- ness of its illustrations, render it eminently suited as a work of reference for the office table of the practitioner. To render it more convenient for the student, it is divided into seven por- tions, corresponding to the leading divisions of medical and surgical science. These are paged separately, and may be had done up in stout covers, each being perfect in itself, and forming con- venient volumes to carry in the pocket to the lecture room, or fitting them to be sent by mail. It will thus be seen that this work affords, at a price unprecedentedly low, a series of digests ofthe medical and surgical sciences, clearly and conveniently arranged, and forming a complete set of HANDBOOKS FOR STUDENTS, as follows:— ANATOMY: '80 large pages, with 157 Illustrations. Price 75 Cents. PHYSIOLOGY: 134 pages, with 40 Illustrations. Price 60 Cents. SURGERY: 122 pages, with 51 Illustrations. Price 60 Cents. OBSTETRICS: 114. pages, wilh 37 Illustrations. Price 50 Cents. MATERIA MEDICA AND THERAPEUTICS; 116 pages, with 29 Illustrations. Price 50 Cents. CHEMISTRY: 94 pages, with 19 Illustrations. Price 40 Cents. THE PRACTICE OF M E D I CI N E; 152 pages, with 3 Illustrations. 50 Cents. Any one of which may be had separate; or, the whole will be done up and mailed, with the postage prepaid, on the remittance of $4; or, if $5 is remitted j The Medical News will be sent in addition. It should be noticed that the amount of matter on a page is unusually large, thus making these Handbooks not only low priced, but extraordinarily cheap. We do not share in the opinion entertained by some, that compendiums of science are not desirable, or with the still smaller number, who esteem them useless. On the contrary, when well executed, they are of essential service to the student; and, so far as we have seen, most of them have contained an amount of in- formation which older individuals—even they who disparage ihem—may be presumed to be far from pos- sessing. Taking the work before us, we can certainly say that no one who has not occupied himself with the different scientific treatises and essays that have appeared recently, and has withal a rare memory, could pretend to possess the knowledge contained in it; and hence we can recommend it lo such—as well as to students especially—for its general accuracy and adequacy for their purposes; and lo the well-informed practitioner to aid him in recalling what may easily have passed from his remembrance. We repeat our favorable impression as to the value of this book, or series of books; and recommend it as decidedly useful to those especially who are commencing the study of their profession.— The Medical Examiner. We have no hesitation in recommending il to students— Southern Medical and Surgical Journal, Dec.lF48. Books of this description are most erroneously denounced, from the supposition that they are intended to take the place of elaborate treatises ; but their object is rather lo assist the student in mastering the elements of medicine, and to aid the practitioner by refreshing his recollection of former studies. In short, a manual or compendium is to the standard text-books in medicine and surgery what "the finder" is to the telescope of the astronomer. It gives to the inquirer a key to the object of his pursuit, and enables him to trace out those parts which require to be especially studied. We have looked through this compendium,and we find that the authors have really succeeded in compressing a large amount of valuable information into a very small com- pass. We recommend this work especially to ihe notice of our junior readers. To those who are about to commence their studies in a medical school it will be found a serviceable guide.—London Medical Gazette. It aims to give a condensed account of every question touching the several branches of medicine, and on this account will arrest the attention of every candidate for his doctorate. It is not simply a work for the in- struction ofthe novices, it may be consulted by the general practitioner with infinite advamage The different departments of which it treats are illustrated by handsome plates, and will serve to impress the mind of the student with clear and definite ideas on the various subjects comprehended in ihe work It is. we think, an excellent book of the kind, and will no doubt become highly popular with the students throughout the United Siates To the medical student it may be confidently recommended as well as to the general prac- titioner whose constant occupation will not allow him the necessary leisure to read more elaborate and comDrehensive works— The New Orleans Medical and Surgical Journal. I will materially assist the student and practitioner in relreshing his knowledge on points previously ac- Quired but upon which he may have become i.i a measure, rusty-tor this purpose .1 is admirably adapted, and we believe will not only prove acceptable to the student of medicine, but also 10 ihe profession at large. — N. Y. Journal of Medicine. Th« irrnrio-emeiii adopted will be found al once concise and clear : while its mechanical execution, its co- aioii/Dictonal illustrations in the branches of anaiomy, physiology, surgery, obstetrics materia medica and jiious ptcioiim ^.^ .^ ]eut cneap,and convenient form, will recommend it lo all such students and cnemistry, TOo£ m des[re t() avnll themselves of whin cannot fail to prove, it kept within ils proper sphere, a convenient *»"" usefuI remembrancer.—jiwiertcan Journal ofthe Medical Sciences. 28 LEA & BLANCHARD'S NEW PUBLICATIONS. LIBRARY OF ILLUSTRATED SCIENTIFIC WORKS, UNDER THIS TITLE LEA & BLANCHARD ARE PUBLISHING A SERIES OF BEAUTIFULLY ILLUSTRATED WORKS, ON VARIOUS BRANCHES OF SCIENCE, BY THE MOST DISTINGUISHED MEN IN THEIR RESPECTIVE DEPARTMENTS. Printed in the handsomest style, and embellished in the most efficient manner. IHt^No expense has been or will be spared to render this series worthy ofthe support of the scientific pub- lic, and at the same time one of the handsomest specimens of typographical and artistic execution which have appeared in this country. Specimens ofthe Engravings and style ofthe volumes may be had on application to the publishers. MTJLLER'S PHYSICS-LATELY ISSUED. P EIN C~I P L E S OF PHYSICS AND METEOROLOGY. BY PROFESSOR J. MULLER, M. D. EDITED, WITH ADDITIONS, BY R. EGLESFELD GRIFFITH, M. D. In one large and handsome octavo volume, with 550 wood-cuts, and two colored plates. This is a book of no ordinary or ephemeral value. It is one of a series, now republishing in London, on the different branches of science, which, from its thorough character and extended range, is much needed in this country. Its design is to render more easily accessible an extensive knowledge of the general principles of physics and meteorology; and the distinguished author has certainly realized the design to a wonderful extent. The subjects treated upon are very numerous—statics, hydrostatics, dynamics, hydrodynamics, pneu- matics, the laws of the motions of waves in general, sound, the theory of musical notes, the voice and hearing. geometrical and physical optics, magnetism, electricity and galvanism, in all their subdivisions, heat and meteorology. The size is nevertheless convenient—one handsome octavo volume, of six hundred pages- ill clear, bold type, and profusely illustrated. In the execution of the illustrations we have rarely seen any thing equal to this American edition.— iV. Y. Commercial. This is a large, elegant, and most admirable volume—the first of a series of scientific books now passing through the press in London, and which cannot fail to commend themselves to the favor of all who take any interest in the progress of science among the great mass of the people. The author is one of the most distin- guished scientific men in Germany, and these works have been prepared with the utmost care, and are put forth in a form admirably adapted to secure that wide circulation and universal favor which they deserve.— JV. Y. Courier and Inquirer. The Physics of Muller is a work superb, complete, unique: the greatest want known to English Science could not have been better supplied. The work is of surpassing interest. The value of this contribution to the scientific records of this country may be duly estimated by the fact that the cost ofthe original drawings and engravings alone has exceeded the sum of £2.000.— Lancet. A work of which all parties may be proud.—Colonization Herald. An excellent work, fully and elegantly illustrated.—Silliman's Journal. From Professor Renwick, of Princeton University. I have been much gratified with the style in which the work is got up. It is not only highly creditable to the publishers, in comparison with other American books of a similar character, but will stand on an equality with the best foreign editions. From Professor W. H. Bartlett, U. S. Military Academy, West Point. I deem this work a most valuable addition to the educational facilities of the country, and a rich source of information to the general reader, as it is truly an elegant specimen of typography. NOW READY. PRACTICAL PHARMACY. COMPRISING THE ARRANGEMENTS, APPARATUS, AND MANIPULATIONS OF THE PHARMACEUTICAL SHOP AND LABORATORY. BY FRANCIS MOHR, Ph. D., Assessor Pharmacia; ofthe Royal Prussian College of Medicine, Coblentzj AND THEOPHILUS REDWOOD, Professor of Pharmacy in the Pharmaceutical Society of Great Britain. EDITED, WITH EXTENSIVE ADDITIONS, BY PROFESSOR WILLIAM PROCTER, Of Ihe Philadelphia College of Pharmacy. In one handsomely printed octavo volume, of 570 pages, with over 500 engravings on wood. Such a manual as the work before us has long been a desideratum in this country. There has heen a great want of a proper text-book of Pharmacy, and io this want may be attributed much of the ignorance which prevails on this subject, in places remote from the large cities. The minute practical instruction which it conveys, will introduce a new era in the shop ofthe apothecary throughout the United States. We recom- mend it, in the strongest manner, to the attention ofthe apothecary and druggist, as well as to the physician who prepares his own prescriptions, as a unique compendium of valuable, practical knowledge m Pharmacy. — Transylvania Med. Journal, August, 1849. In preparation, works on Metallurgy, Food, the Steam Engine, Machines, Astronomy, Rural Economy, tCc. LEA & BLANCHARD'S NEW PUBLICATIONS. 29 Library of Illustrated Scientific Works. (Continued.) KNAPP'S CHEMICAL TECHNOLOGY. TECHNOLOGY; OR, CHEMISTRY APPLIED TO TIIE ARTS AND TO MANUFACTURES. BY DR. F. KNAPP, Professor at the University of Giessen. JSdlted, with numerous J\'otes and Additions, by DR. EDMUND RONALDS and DR. THOMAS RICHARDSON. First American Edition, with Notes and Additions, By Professor WALTER R. JOHNSON. In two handsome octavo volumes, printed and illustrated in the highest style of art. Volume One, lately published, with two hundred and fourteen large wood engravings. Volume Two, now ready, with two hundred and fifty wood engravings. One of the best works of modern times.—New York Commercial. We think it will prove the most popular, as it is decidedly the best of the series. Written by one who has for many years studied both theoretically and practically the processes which he describes, the descriptions are precise, and conveyed in a simple unpretending style, so that they are easily understood, while they are sufficiently full in detail, to include within them everything necessary to the entire comprehension of the operations. The work is also carefully brought down to include the most recent improvements introduced upon the continent of Europe, and thus gives us full descriptions of processes to which reference is fre- quently made in other works ; while many of them are. we believe, now for the first time presented in a com- plete state to the English reader.— Franklin Institute Journal. In addition lo the valuable scientific matter contained in the original work, very extensive American addi- tions have been made to ilby the editor, which are exceedingly valuable, and of much interest to the general reader. The publishers have spared no pains in bringing out a work of superior mechanical execution and rare excellence, with numerous skilfully engraved cuts, designed to illustrate the various subjects treated in this work. We feel confident that, as a truly useful publication, it will be eagerly sought after and highly appreciated—N. Y. Farmer and Mechanic. We nail the pleasure of noticing, in a former number, the first volume of this excellent work, and of ex- pressing our high sense of its value. We need say little more, therefore, of its continuation, than thai it fully sustains the character Of its predecessor, both in regard to the value ofthe original treatise, and the number and importance of the additions which have been made to it by the- English editors.—The British and Foreign Medico-Chirurgical Review. When we say that this volume begins another of the superb J' Library of Illustrated Books," republished from the London scries by Lea & Blanchard, of which Muller's Physics and Meteorology, and Weisbach's Mechanics and Engineering (the first volume ofthe latter), have already appeared; that the present work is on a subject coming home to the business and bosoms, because to the economic interests of Americans; that its American editor is Prof. Walter R. Johnson, who has enriched it with numerous valuable additions, the results of his own industrious researches in the technological sciences ; and that it is illustrated and printed in the same superb style which marked the previous works:—we have sufficiently explained to our readers the value of a work which will not need any other commendation.—North American. No mechanic, student of chemistry, miner, or manufacturer should omit purchasing this work. It will be found useful, interesting, and instructive to all.—Pittsburgh Commercial Journal. WEISBACH'S MECHANICS. PRINCIPLES OF THE MECHANICS OF MACHINERY AND ENGINEERING, By Professor JULIUS WEISBACH. TRANSLATED AND EDITED BY PROFESSOR GORDON, OF GLASGOW. First American Edition, with Additions By Professor WALTER R. JOHNSON. IN TWO OCTAVO VOLUMES, BEAUTIFULLY PRINTED. Volume One, with 550 illustrations, just issued. Volume Two, with 350 illustrations, now ready. The second volume of this work embraces the application of the Principles of Mechanics to Roofs, Bridges, Platform Scales, Water Powers, Dams, Water Wheels, Turbines, Water Engines, &c. &c. This work is one ofthe rrost interesting to mathematicians that has been laid before us for some time ; and we may safely term it a. scientific gem.— The Builder. -,.,_■. .... The most valuable contribution to practical science that has yet appeared in this country— Athenaum. Unequalled by anything ofthe kind yet produced in this country-the most standard book on mechanics, machinery, and engineering now extant— N. Y. Commercial. Tn,.rm„-, In every way worthy of being recommended to our readers -Franklin Institute Journal. What the " MCcanique Celeste" is to the astronomer, a treasury of principles, facts, and formulae, on which he may draw on almost any and every occasion, that can be conceived to arise hi the field either of demon- stration or operation.—Methodist Quarterly Review. From Charles H. Haswell, Esq., Engineer in Chief, U. S. N. Tt«. ,t*«i ror me j-m i||us,rationSi i„ the fullness of their construction, and in typographical execution, are wihmat"a parallel. It will afford me much pleasure to recommend its use to the members of the profession with which 1 am eonnected. ■v 30 LEA & BLANCHARD'S PUBLICATIONS. YOUATT &, SKINNER'S GREAT WORK ON THE HORSE. THE HORSE. By William Youatt. A NEW EDITION, WITH NUMEROUS ILLUSTRATIONS: Containing a full account of the Diseases of the Horse, with their mode of treatment; his Ana- tomy, and the usual operations performed on him; his Breeding, Breaking, and Manage- ment; and hints on his Soundness, and the Purchase and Sale. TOGETHER WITH A GENERAL HISTORY OF THE HORSE; A Dissertation on the American Trotting Horse, how Trained and Jockeyed, an account of hia remarkable performances; and AN ESSAY ON THE ASS AND THE MULE. BY J. S. SKINNER, Assistant Postmaster-General, and Editor of the Tnrf Register. In one large and handsome octavo volume, with numerous wood-cuts. This edition of Youatt's well-known and standard work on the Management, Diseases, and Treatment of the Horse, has already obtained such a wide circulation throughout the country, that the Publishers need say nothing to attract to it the attention and confidence of all who keep Horses or are interested in their improve- ment. CLATER'S FARRIER. EVERY MAN HIS OWN FARRIER: CONTAINING THE CAUSES, SYMPTOMS, AND MOST APPROVED METHODS OF CURE OF THE DISEASES OF HORSES. BY FRANCIS CLATER, Author of "Every Man his own Cattle Doctor," AND HIS SON, JOHN CLATER. FIRST AMERICAN, FROM THE TWENTY EIGHTH LONDON EDITION. WITH NOTES AND ADDITIONS BY J. S. SKINNER. In one 12mo. volume, cloth. CRATER'S CATTLE DOCTOR. EVERY MAN HIS OWN CATTLE DOCTOR. Containing the Causes, Symptoms, and Treatment of all Diseases incident to Oxen, Sheep, and Swine; And a Sketch of the Anatomy and Physiology of Neat Cattle. BY FRANCIS CLATER. Edited, Revised, and almost Rewritten, by William Youatt. With Numerous Additions, em- bracing an Essay on the Use of Oxen, and the Improvement in the Breed of Sheep, by J. S. Skinner, Assistant Postmaster-General. In one duodecimo volume, cloth, with numerous illustrations. YOUATT ON THE PIG. THE PIG: A Treatise on the Breeds, Management, Feeding, and Medical Treatment of Swine, with Directions for Salting Pork, and Curing Bacon and Hams. By WM. YOUATT, V. S., Author of " The Horse," " The Dog," " Cattle," " Sheep," &c. &c. ILLUSTRATED WITH ENGRAVINGS DRAWN FROM LIFE, BY WILLIAM HARVEY. In one handsome duodecimo volume, extra cloth, or in neat paper cover, price 50 cents. YOUATT ON THE DOG. THE DOG. By William Youatt, Author of "The Horse/' &c. WITH NUMEROUS AND BEAUTIFUL ILLUSTRATIONS. EDITED BY E. J. LEWIS, M.D., &c. &c. In one beautifully printed volume, crown octavo. JOHNSON AND LANDRETH ON FRUIT. KITCHEN, AND FLOWER GARDENING. A DICTIONARY OF MODERN GARDENING. By George William Johnson, Esq., Aulhor of the " Principles of Practical Gardening," "The Gardener's Almanac," &c. With one hundred and eighty wood-cuts. Edited, with Numerous Additions, by David Laudreth. of Philadelphia. In one large royal duodecimo volume, extra cloth, of nearly six hundred and fifty double-columned pages. THE COMPLETE FLORIST. A MANUAL OF GARDENING: containing Practical Instructions for the Management of Greenhouse Plants, and for the Cultivation of the Shrubbery, the Flower Garden, and the Lawn; wiih Descriptions of those Plants and Trees most worthy of Culture in each Department. With Additions and Amendments, adapted to the Climate of the United States. In one small volume. Price only twenty-five cents. THE COMPLETE KITCHEN AND FRUIT GARDENER. A SELECT MANUAL OF KITCHEN GARDENING, and the Culture of Fruits; containing Familiar Directions for the most approved Practice in each Department, Descriptions of many valuable Fruits, and a Calendar of Work to be performed each Month in the Year. The whole adapted to the Climate of ihe United Slates. In one small volume, paper. Price only twenty-five cents. LANDRETH'S RURAL REGISTER and ALMAMC for 1848, WITII NUMEROUS ILLUSTRATIONS, niill on hand, a few copies of the REGISTER for 1847, with over one hundred wood-cuts. This work has 150 large 12mo. pages, double columns. Though published annually, and containing an almanac, the piin- cipal part of the matter is of permai.ent utility lo the horticulturist and farmer. i . M CONTENTS OF THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES. April, 1849. ORIGINAL COMMUNICATIONS. . . . . Memoirs and Cases pp. 277-410. n i u ,r\t °n the Intima,e Structure and History of the Articular Cartilages. (With two plates.) It. Jack.-oi\ s Observations on Hydrophobia, with cases, in one of which chloroform was administered with a favorable result. III. Meigs' Hisiory of Five C;ises of Psruclo-membranous Laryngitis or true Croup; in three of which the Operation of Tracheotomy was performed, and in two successfully. IV. Parkman's Ex- tracts from the Records ofthe Boston Society for Medical Improvement. V. Sargent's Report of the Cases ot ™i 1',, recelved """ tne Philadelphia City Hospital in 1.-45-6. VI. Peaslee's Case of Ovarian Dropsy. VII. Warren on the Effects of Chloroform as a Narcotic Agent. VIII. Bond's Cases of Retroversion of ihe Uterus, with a description ofa Newlnstrument for its Restoration. (With two wood-cuts.) IX. Ruschenber- ger's Cases of Extraction of a glass goblet from the Rectum—Fracture of the Penis. (With a wood-cut.) „ _., Reviews, pp. 411-441. X. Obstetncs,the Science and the Art. By CD. Meigs, M. D. With 121 cuts, 8vo. pp. 685. XI. Reports on Lunacy. Bibliographical Notices, pp. 442-464. XII. Ames on Epidemic Meningitis. XIII. Mauley's Anniversary Discourse. XIV. Stevens's Plea of Humanity in Behalf of Medical Education. XV. Kirkesand Paget's Manual of Phvsiology. XVI. Bowman's Introduction to Practical Chemistry, including Analysis. XVII. Morfit and Muckle's Chemical and Phar- maceutical Manipulations. XVIII. New York Report on the subject of Asiatic Cholera. XIX. Philadel- phia Report on Public Hygiene. XX. Summary ofthe Transactions ofthe CollegeofPhysiciansof Philadel- phia, from September 16, lS48,to January 2,1S49, inclusive. QUARTERLY SUMMARY OF THE IMPROVEMENTS AXD DISCOVERIES IN THE MEDICAL SCIENCES, FOREIGN INTELLIGENCE. Anatomy and Physiology, pp. 465-467. I. Paget on the Blood Corpuscles of the Human Embryo. 2. Schiffon the Changes in the Lungs after Di- vision of the Pneumogastric Nerves. 3. Hamernik on the Mechanism of the Heart. Organic Chemistry, pp 467-470. 4. Lehmann on the Nature ofthe Gastric Juice. 5. Wohler and Frerichs on the Changes of Organic Sub- stances on their passage into the Urine. 6. Regnault and Reiset on the Chemical Changes of Respiration. 7. Dr. Bernard ou the Source of Sugar in the Animal Economy. Materia Medica and Pharmacy, pp. 470-476. 8. Pereira on Cod-Liver Oil. 9. Bouchardat and Stuart- Cooper on the Physiological and Therapeutic Ac- tion of Atropia. 10. Chavannes on the advantages of Chloride of Gold as a Causlic. 11. Millon on the Nutritive Properties of Bran. 12. Donovan on Vegetable Infusions. Medical Pathology and Therapeutics and Practical Medicine, pp. 476 499. 13. Dr. MomberCs Case of Hydrophobia Spontanea. 14. Valleix on Muscular Rheumatism. 15. Solon on Bilious Pneumonia. 16. Rilliet on Melaena Neonatorum. 17 Elam on Chorea. 18. Schneider on Sangui- neous Perspiration. 19 Dr. Pickford^s Case in which the Physical Signs ofthe posiuon ofthe Heart werede- cepiive. 20. Jaksch on ihe Signs of Diseased Heart afforded to the hand laid over the Praecordium. 21. Bellingham on Polvform Concretions in the Cavities of the Heart. 22. O'Ferrel on Pleuritis simulating Pericarditis. 23. Greene on Encysted Tubercles in the Lungs. 24. Mayne on Phthisis in the Infant. 25. M. Levy on Acute Tubercular Meningitis in the Adult. 26. Patterson's Case of Variola in which the Eruption was found in the Mucous Membrane of the Colon. 27. Watson on Intra-Utenne Small-Pox. 2-i. Gamberini on Nocturnal Neuralgia of the Forearm. 29. Bennet on Spontaneous cure of Ovarian Dropsy, by means of an Ulcerative Opening of the Cyst into the Bladder. 30 Delasiauve on the Treatment of Epilepsy. 31. Melsens on Iodide of Potassium in Saturnine Affections. 32. Wtlige on the external use of Iodine in Croup. 33. Koreffon Spigelia Marylandicain Pruritus Ani. 34. Owen Reese on Lemon Juice in Rheumatic Gout. 35. Necins on the employment of Nux Vomica in the Diarrhosa of Exhaustion. 36. Dr. Pickford on the Beneficial Effects of Coffee in Infantile Cholera. 37. Palsy of the Tongue cured by galvano-puncture. 38. Manzolini and Quaglino on the Injection of various substances into the Veins. Surgical Pathology and Therapeutics and Operative Surgery, pp. 499-508. 39. Guthrie on Hospital Gangrene. 40. Toynbee's Pathological Researches into the Diseases of the Ear. 41. Till on Ovarian Dropsy. 42. Hancock on Aneurism ofthe Axillary Artery. 43. Cooper on Ligature of Subclavian followed by incessant Cough. 44. Willis on Inguinal Aneurism—Ligature ofthe left external Iliac Artery. 45. Tufnell on Femoral Aneurism—Compression tried without success—Amputation. 46. Blandin on Wound of the Right Kidney successfully treated. 47. Sewell on Lateral Transfixiure of the Chest by a Scythe Blade, followed by complete recovery. 48. Neuhold and Hasserbronc on the Employment of Sugar of Lead in Sirangulated Hernia. 49. Vidal's New Method of Treating Urethral Pains following Gonorrhoea. 50. Thevenot and Boyer on Luxation of the Astragalus inwards ; Reduction. 51. Mendoza on Vertical Dislocation ofthe Patella. 52 Greenhow on Excision of the Os Calcis. 53. Syme on Excision of the head ofthe Femur in Morbus Coxarius. 54. Christophers'1 new mode of removing Naevi. Ophthalmology, pp. 50S-509. 55. Mackenzie's Case of Cysticercus Cellulosa in the Human Eye 56. Dixon's Case of Foreign Body in the Eye. Midwifery, pp. 509-517. 57. Routh on the Causesof the Endemic Puerperal Fever of Vienna. 58. Burdonon the Influence ofthe Mother's Imagination upon the Production of Monstrous Children. 59. Mitchell on Ulceration of the Os and Cervix Uteri treated with Solution of Gun-Cotton. 60 Webster on the Siatistics, Pathology, and Treatment of Puerperal Insanity. 61. In what cases (other than of Contracted Pelvis) is it proper to induce abortion or Premature Labor. By Dubois. 62. Scanzoni on the Cause of Hemorrhage in the latter months of Preg- nancy in Cases of Placenta Prasvia. 63. Ducresl on Cerebral and Meningeal Phlebitis in Puerperal Women. Cholera, pp. 517-524. 64. Taylor on the Chemical Examination of tjie Liquid Vomited during Cholera. 65. Boehm on the Micro- scopic Examinations of the Mucous Membrane of the Stomach and Bowels in Cholera 66. Lamprey on Terchlonde of Carbon as a Remedy for Cholera. 67 Little on Quinine in Cholera. 68. Robertson on Blood- Letting in Cholera 09. Robertson on the Injeciion of Saline Solution into the Veins in Cholera. 70. Fretten- bacher's Conclusion respecting the mode of Propagation of Cholera in Russia, in lt47-43. Anesthetic Agents, pp. 524-530. 71. Malgaigne on the Action of Chloroform. 72. Deaths from Chloroform. 73. Nunneley on the Chloride of Olefiaiit Gas as an Anaesthetic. 74 Simpson on Naphtha as an Anaesthetic. 75. Higginson on Anaesthesia from the local application of Chloroform. 76. Snow on Chloroform iu Midwifery. Medical Jurisprudence and Toxicology, pp. 530-532. 77. Boucheton the Lunatic Asylum, Nantes. 78. Smith on Early Menstruation and Pregnancy. Miscellaneous, p. 532. 79 Dr. Spengler on Influenza and Ozone. (For remainder of Contents, see next page.) 31 Two Medical Periodicals for Five Dollars. THE AMERICAN" JOURNAL OF THE MEDICAL SCIENCES, EDITED BY ISAAC HAYS, M. D., Is Published Quarterly ON THE FIRST OF JANUARY, APRIL, JULY, AND OCTOBER. Each Number contains about Two Hundred and Eighty Large Octavo Pages, And is appropriately Illustrated with Engravings on Copper, Stone, Wood, &c. The variety and extent of its contents may be estimated from the very condensed summary ofthe Number for April, 1849, on the preceding page. THE MEDICAL NEWS AND LIBRAKY Is Published Monthly, and consists of THIRTY-TWO VERY LARGE OCTAVO PAGES, Containing the Medical Information of the day, as well as a Treatise of high character on a prominent department of Medicine. WATSON'S LECTURES ON THE PRACTICE OF PHYSIC, BRODIE'S CLINICAL LECTURES ON SURGERY, AND TODD & BOWMAN'S PHYSIOLOGY Have thus appeared in it, and the work at present publishing is WEST OS THE DISEASES OF INFANCY AND CHILDHOOD. Which will be completed in the present year. TERMS. THE SUBSCRIPTION TO THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES IS FIVE DOLLARS PER ANNUM. When this amount is paid in advance, the subscriber thereby becomes entitled to the MEDICAL NEWS AND LIDRARY FOR ONE YEAR, Without further charge. For the small sum, therefore, of FIVE DOLLARS, the subscriber can obtain a Quarterly and a Monthly Journal ofthe highest character, presenting about FIFTEEN HUNDRED LARGE OCTAVO PAGES, "With appropriate Illustrations: Or, for TEN DOLLARS, the Publishers will furnish TWO COPIES OF THE JOURNAL, AND THREE OF THE NEWS; Or, for TWENTY DOLLARS, FIVE COPIES OF THE JOURNAL AND FIVE OF THE NEWS. Presenting strong inducements to Clubs, and rendering these among THE CHEAPEST OF AMERICAN MEDICAL PERIODICALS. When the News is ordered separately, the price is One Dollar per annum, invariably in advance. CONTENTS OF JOURNAL. (Continued from preceding Page.) AMERICAN INTELLIGENCE. Original Communications, pp. 533-536. Clements Case of Trismus Nascentium, illustrative ofthe influence of position of the patient. Housloun't Case of Ovarian Dropsy cured by the long Abdominal Incision in 1701. Domestic Summary, pp 536-552. Leidy on the Development ofthe Purkinjean Corpuscle in Bone. -Leidy on the Arrangement of the Areolar Sheath of Muscular Fasciculi and its relation to the Tendon. Leidy on the Intermaxillary Bone in the Em- bryo of the Human Subject. (With two wood-cuts.) Eve on Lithotomy—117 Calculi weighing 4i ounces, successfully removed. Van Buren's Case of Inguinal Aneurism—Compression tried without success— Ligature of the Artery. Holster ou Trephining for Epilepsy. Whitmire on Iodine in the Treatment of Snake- bites. Fenner on Cholera in New Orleans. Iron Rod weighing 13J pounds driven through the Head—Re- covery. By Dr. Harlow. Hamilton on Death from pressure of an enlarged Thyroid Gland. Taylor on Superfcelation and Mixed Births. Jackson's Case in which a large quantity of Chloroform was used. Hays on Local Aneesthesia in Neuralgia. Stille on Chloroform in Nephritic Colic. Army Surgeons. Table of Contents, Index. &c. 20 pages. J /T\ \ i frrml (If Of MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONA I \,