i$*w; iiOi i NATIONAL LIBRARY OF MEDICINE Bethesda, Maryland c > G> i Q\ A SYSTEM n OF HUMAN ANATOMY, GENERAL AND SPECIAL. BY ERASMUS WILSON, M.D., LECTURER ON ANATOMY, LONDON. FOURTH AMERICAN FROM THE LAST LONDON EDITION. EDITED BY PAUL B. GODDARD, A.M., M.D., PROFESSOR OF ANATOMY AND HISTOLOGY IN THE FRANKLIN MEDICAL COLLEGE OF PHILADELPHIA. /T~^.l WITH BY G^BE3^ I U. S. NavalTecTiea'- So o^. , PHILA.DJBL.PHIA:^ BLA N CH A RDJN D J.EA. ■ J 1853. Entered, according to Act of Congress, in the year 18>», uy LEA AND BLANCHARD, in the clerk's office of the District Court of the United States lor t Eastern District of Pennsylvania. Printed by T K & P. G Collin*. f)\.2-7 TO 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, &\>t8 carork IS RESPECTFULLY INSCRIBED 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 now, 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) rin 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 ch'anges 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, 1S44. PREFACE TO THE FOURTH LONDON EDITION. [n 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. T'o 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 stanflird 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, throughout, 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. Paere Definition.........................33 Chemistry of the tissues..............33 Nitrogenized substances..............35 Non-nitrogenized substances...........3C 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 vertebras...................53 Lumbar vertebra?..................53 General considerations.............54 Development.....................55 Attachment of muscles.............56 Sacrum ........................5G 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......................V8 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. Orbits........................... 90 Nasal fossae....................... 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.................112 Phalanges......................113 Pelvis and lower extremity...........114 Os innominatum.................114 Ilium..........................H4 Ischium........................ 115 Os pubis.......................H6 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 vertebrae......... 144 Pag* 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 extremity 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 Metacarpo-phalangeal 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..... 107 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 Arrangement 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-thy roideus. 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 uvula—Palato-glossus......195 Palato-pharyngeus—Actions ... .195, 196 Praevertebral muscles—Dissection......19P Rectus anticus major—Rectus anticus minor.....................19fi 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 .........202 Fourth layer—Dissection..........202 Sacro-lumbalis—Longissimus dorsi 203 Spinalis dorsi.................203 Cervicalis ascendens—Transversa- ls colli....................204 Trachelo-mastoideus — Complexus 204 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 spinas—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 urethras..............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 Snpra-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—Jjissection...........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 radiahs longior ... 235 Extensor carpi radialis brevior.. .. 235 Extensor communis digitorum.... 235 Extensor minimi digiti..........236 Page 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 vaginae 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. XVII CHAPTER V. THE FASCIAE. Page General anatomy...................263 Fascia of the head and neck......264 Temporal fascia..................264 Cervical fascia...................264 Fascije 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 fasda................269 Fascije of the upper extremity ... 271 Fasci.b 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 Superficialis crrvicis..............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.................31'7 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 Xvili CONTENTS. CHAPTER VII. THE VEINS. Page 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 Pagfl Venae innominataa................345 Superior vena cava.......,.......345 Iliac veins......................345 Inferior vena cava................346 Azygos veins....................349 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 Lymphatics of the trunk............356 Page Lymphatics of the viscera............357 Lacteals........................358 Thoracic duct.....................359 Ductus lymphaticus dexter...........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...................443 CONTENTS. XIX CHAPTER X. ORGANS Nasal 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 THE V 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 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 gland.....................556 Thymus gland.....................556 DF SENSE. Page 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 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 Vesicula? 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 THE F02TUS. Pare Foetal 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 CHAPTER XI. CHAPTER XII. V 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 ' f 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. Pa$« 46. Capsule of temporary incisor..... 97 47. Temporary tooth with capsule of permanent..................• 98 48. Os hyoides................... 99 49. Thorax....................i. 101 50. Scapula......................104 51. Humerus....................106 52. Ulna and radius...........----108 53. Bones of the carpus; posterior view 109 54. Hand; anterior view.......t. ... 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 14b 84. Id. id. id---148 85. Ligaments of the sternal end of the clavicle and costal cartilages.... 150 88. Ligaments of the scapula and shoulder joint...............151 (xxi) XXli TABLE OF ILLUSTRATIONS. Fists. 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. P«g« 134. Muscles of the posterior tibial region, deep layer..................256 135. Dorsal interossii...............259 136. Muscles of the sole of the foot; 1st layer......................259 137. Muscles of the sole of the foot; 2d layer......................260 138. Deep-seated muscles............261 139. Plantar interossii..............263 140. Section of the neck, showing the distribution of the deep cervical fascia....................•• 265 141. Transverse section of the pelvis, showing the distribution of the fasciae.....................269 142. Deep perineal fascia ...........270 143. Distribution of the deep perineal fascia ; side view.............270 144. Distribution of the fasciae at the femoral arch................273 145. The great vessels of the chest .... 278 146. Branches of the external carotid artery......................284 147. External carotid...............289 148. Branches of the subclavian artery. 296 149. The circle of Willis............298 150. Axillary and brachial arteries .... 301 151. Arteries of the fore-arm—Radial and ulnar...................304 152. Branches of the abdominal aorta. . 310 153. Cceliac axis with its branches..». 312 154. The superior mesenteric artery ... 313 155. The inferior mesenteric artery.... 314 156. The internal iliac artery with its branches...................317 157. The arteries of the perineum.....319 158. The femoral artery with its branches 323 159. The anterior tibial artery........328 160. Posterior tibial and peroneal artery 330 161. Arteries of the sole of the foot____332 162. Sinuses of the dura mater.......339 163. Sinuses of the base of the skull... 340 164. Veins and nerves of the bend of the elbow......................342 165. Veins of the trunk and neck.....346 166. The portal vein...............350 167. The thoracic duct.............360 168. Minute structure of nerve.......363 169. The centrum ovale majus and cor- pus callosum................373 170. The lateral ventricles of the cere- brum ......................374 171. Longitudinal section of the brain. . 377 172. Base of the brain..............384 173. Distribution of the fibres of the brain 387 .174. Sections of the spinal marrow .... 391 175. Sections of the spinal cord.......392 176. The olfactory nerve............393 177. Origin of the optic and fourth nerves 394 178. The isthmus encephali, showing the thalamus opticus, corpora quadri- gemina, pons Varolii, and medulla oblongata...................394 TABLE OF ILLUSTRATIONS. XX1U Pipp. 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.......417 188. 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. Great sympathetic..............439 198. Fibro-cartilages of the nose......443 199. Longitudinal section of the globe of the eye...................446 200. Venae vorticosae 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...........453 204. 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 vesiculse 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......546 243. 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 56] A SYSTEM OF HUMAN ANATOMY. CHAPTER I. INTRODUCTORY. BY THE EDITOR. Anatomy (derived from avars^nv, 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 tifle 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 Dulk 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, and fluorine. 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 ut the pineal gland. Phosphate of soda and ammonia, in urine and blood; but probably only 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 caecum. 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 ename.. Silica and oxide of manganese, in the hair. Alumina, in the enamel. HISTOLOGY. 35 Oxide of iron, in blood, black pigment, lens, and hair. 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 •>f NH and the other of CH; their elements may only have united tor 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, arid is so called because, itself a primary sub- stance, it originates so many dissimilar substances. It consists of C40 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. Fibtin(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 C48 HJ2 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+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 0M. 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, biliphcdn, 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 laciis, and composed of Cs H4 04 + HO. It crystallizes in four-sided prisms, and has a sp. pr of 1.543. It also contains an acid called lactic (C6 H5 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 TI SSUES. 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 the nucleated corpuscle or cell, which is a little vesicle or bag, containing a fluid in its early stage, ahd 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 (evanesced). 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. Simple membrane, 2. Pigmentary membrane, 3. Tesselated epithelium, 4. Cylindroid epithelium, 5. Ciliated epithelium, 6. Aggregated epithelium. White fibrous tissue (inelastic). Yellow fibrous tissue (elastic). Epithelial tissue, presenting several < varieties. • A group of vegetable cells. 4 ]. Nucleus. 2. Nucleoli in nucleus. 38 HISTOLOGY. 4. Cartilaginous tissue. 5. Osseous tissue. 6. Petrous tissue. Compound Tissues: , ,, i £1 ^- ( 1. Striped muscular fibre, 1. Muscular fibrous tissue, j ^ Uns^riped 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 lamina?, 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 tneir 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, w^hich 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 undei 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 been 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 wrater 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 twro 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 permanent 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 wre 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 Fi # size; a transparent wall is seen to spring up like a watch-glass from one • ® 0 £\ iT) (T^) Si(ie °f the Sranule> wnicn swells up ^ W \J $J 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. 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 fig1. 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 Flg* • 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 occu. 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. 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. § ilode 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; thty ^ive 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 Fluateoflime...........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. of vessels and nerves. They articulate with long bones by means of smooth surfaces plated with cartilage, and with 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, diplde. 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, vertebrae, 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 Fig. n* (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 E1?5T} 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 21 (j 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- diu«vig» 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 tha 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 thn 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, wTith the first tw^o pieces. Articulations.—With four bones; the last lumbar vertebra, ossa inno- minata, 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 (xo'xjcug 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 female 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,Hs divisible into two parts,—\the craniumvajrid 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 22* Ss^4/ Occipital BoNE.-^This bone is situated at the posterior part and base of the cranium. J It is trapezoid in figure, and divisible into two surfaces, rfour 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 thetexternal occipital Xjprotuberance; 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. (JJirectly behind each condyle is an irregular fossa, and a small opening, the (posterior condyloid foramen, fox 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. Tn 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; I 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 Jthe internal occipital protuberance, which corre sponds with the similar process situated upon the external surface of the bone. The convergence of the four grooves forms 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. The 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 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 of the pddita- 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 afre 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 condy'oid 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. Fig. 24.* Parietal Bone. — The parietal bone is situated at the side and ver- tex of the skull; it is quadrilateral ini 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'tonporal fascia is attached. In the middle of this line, and nearly in the (MmtreTof 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 ; below7 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 f 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 bpposite 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- 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 portion is a projection, the frontal eminence.j Below these points are the superciliary ridges, large towards their inner termination, and becoming gradually smaller as they arch outwards: they support the eyebrows. Beneath the superciliary ridges are the sharp and prominent arches which form the upper margin of the orbits/the supra-orbital ridges.} Externally the supra-orbital ridge terminates in the (external angular process, and internally in the"internal angular process; at the inner third of this ridge is a notch, sometimes converted into ayforamen, the Uupra-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-j 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 wThich 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. •5. 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. 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- i jecting process, the nasal spineJ 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 Cforamen caecum. 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 calledfdigital fossae, which correspond with the convolutions of the anterior lobes of the cerebrum. The superior border 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 whicn the figure 8 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 Bhow the orbito-nasal portion. 1. The grooved ridge for the lodgment of the superior longitudinal sinus and attachment of the falx. 2. The foramen caecum. 3. The superior Fig. 27.-J- 64 TEMPORAL BONE. through life. The frontal sinuses make their appearance during the firs' 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, mafetpid, 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 and lengthened process, the zygomal) Near the commencement of the zygo- ma, upon its lowTer border, is a project. tion called the tubercle, to which is at- 1 tached the external lateral ligament of J 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 ooetiing 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 j it is thick, and hollowred 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.f The meatus auditorius 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 branch of the 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- sure, and a minute foramen ; 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 aquceductus 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 aquceductus cochleae, 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 arnoiged in a curved line from above downwards, are four or * The left temporal bone, seen from within. 1. The squamous portion. 2. The mastoid por*ion. 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 aquaeductus cochleae, while the num- ber itself is situated on the bony lamina which overlies the opening of the aquaeductus 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. tA. 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 aquaeductus Fallopii. The openings following that of the aquaeductus Fallopii in a curved direction require no reference. 3. The cluster of three or four oblique Fig. 30.t TEMPORAL BONE. e: five openings, the two upper ones being the largest, and occupying the superior compartment of the reniform fossa, and the two or three ini'erioi 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 aquaeductus 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, thestyloid process, occasionally connected with the bone only by cartilage, aucTTost during maceration, particularly Unjhe young subject. At the base of this process is a rough sheath-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 aquasductus Fallopii. 7. Part of the carotid canal. c. The annulus membranas tympani or temporal bone of the foetal skull, right side. 63 TEMPORAL BONE. large oval opening, the carotid foramen, the commencement of the caiotid 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 difleren in different bones; but in all, the fossa presents a vertical ridge on it inner side, which cuts off a small portion from the rest. The upper par 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 lowTer 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 memhrance tympani; and one for the styloid process. Ossification occurs in these pieces in the following order: in the squamous portion immediately aftei 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.—Ho 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, dieastricus and retrahens aurem; by the styloid process, to the stylo- pnaryngeus, 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 (chiura, and one (not constant) for the angle of the os pubis. Ossification PELVIS. 117 commences in the pnmitive pieces, immediately after that in the vertebra?, 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 vaginae 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 urethras. 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 urethra?, and obturator internus; and by the ramus, the adductor magnus, and accelerator urinae. PELVIS. The pelvis considered 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 Iv.mbar vertebra with the fourth and sacrum. 3. The promontory 118 PELVIS. the symphysis pubis, expanded on each side, and encroached upon be- 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 with 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 knowledge 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 fcetus during parturition. There are certain striking differences between the male and female pel- vis. In the male jthe 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 of the 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 of the sacrum, on which its transverse lines and foramina are seen. 5. The tip of the 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. {. The spine of the pubes ; the prominent ridge between h and t 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 of the 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. Fig. 57.« FEMUR. 110 J~i 1. - -. 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 fivelnches. 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- / — 'r. The shaft of the femur is convex and rounded in * The right femur, seen upon the anterior aspect. 1. The shaft. 2. The head. 2 The neck. 4. The great trochanter. 5. The anterior intertrochanteric line. 6 Tha 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 of the popliteus muscle. 11. The tuberosity for the attachment of the interna*. 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, wThich descend to the twro 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 upwards. 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 of the 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, which 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 q f 'he linea quadrati, into which the quadratus femoris is inserted. The outer lip is occu pied by g m, the gluteus maximus; and 6, 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 cruraeus 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 wdiich 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, cruraeus, 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- moid 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 w7ith 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 patellae, 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 tht 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 of the 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 (rfsfo'vv), 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. ,,,,.. . • ,, , H ' The lower extremity is flattene'd 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 1 .order oetween 1 and 6 is the crest of the tibia. FIBULA. 123 downwards beyond the articular surface of the tibia, forming the externa*) malleolus. Its external side presents a rough and triangular surface, which is subcutaneous. Upon the internal surface is a smooth triangular facet, to articulate writh the astragalus; and a rough depression, for the attach- ment of the interosseous ligament. The anterior mirder 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 jpart. 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 of the 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 of the external malleolus. The external border begins at the base of the styloid process upon the head of the 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- cess. 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 muscie. o. The po- Dliteal 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 innei .Tialleolus. 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 by the oblique line immediately above the number. 11. The styloid process on the head of the fibula for the attachment of the tendon of the biceps rruscle. 12. The subcutaneous surface of the lower part of the shaft of the fibula. 13. The external malleolus formed by the lower extremity of the fibula. 14. The groove upon the pos- terior part of the external malleolus for the tendons of the peronei muscles. Fig. 60.* 124 TARSUS—ASTRAGALUS—CALCANEUS. taking place in the inferior epiphysis during the second year, and in tne 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 two 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. (f£he external presents a lar^e triangular arttcuTar 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. f 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. fThe superior I 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 posteriorlyT5y~tKe two' inferior tuberosities, of wdiich the internal is broad and large, and the ex- ternal smaller and prominent. The external surface is convex and sub- v cutaneous, and marked towards its anterior third by two grooves, often v separated by a tubercle, for the tendons of the 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 ^Jiis SCAPHOID AND CUNEIFORM BONES. 125: surface is a projecting process (sustentaculum tali), Fis- 61-* wrhich supports the anterior articulating surface of the 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 two 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 two grooves sulcus tali and calcanei. This groove is called the sinus tarsi, and serves to lodge a strong interosseous ligament which binds the two 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, v 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 o[ the first and second toes. 10. The first phalanx of the great toe. 11. The second phalanx of the great toe. 12. The first phalanx of the second toe. 13. Its second phalanx. 14. Its third phalanx. 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 wdiich 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.A 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 the 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 whule,N 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. .27 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 bone. 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 writh 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'N 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\Jhree articular facets, for die 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. Y The fifth is recognised by its broad baseband 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 digital 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 vertc- 128 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.—Ho fourteen; to the first, the peroneus longus and first dorsal interosseous muscle; to the second, two dorsal interossei and transversus pedis; to the third, two dorsal and one plantar interosseous, adductor pollicis and transversus pedis; to the fourth, twTo 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. The middle cuneiform bone. 9. The external cuneiform bone. 10, 11. The cuboid bone. 11. Refers to the groove for the tendon of the peroneus longus : the prominence between this groove and figure 10 is the tuberosity. 12, 12. The metatarsal bones. 13, 13. The first phalanges. 14, 14. The second phalanges of the four lesser toes. 15, 15. The third, or ungual phalanges of the four lesser toes. 16. The last phalanx of the great toe. 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 the 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 of the common tendon of the extensor longus and extensor brevis digitorum, and flexor brevis digitorum. Third phalanges; twro 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 of the 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 metacarpo-phalangeal 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 of the 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 i 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 ( false. ICO 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 patellae, is the prolongation of the tendon of the extensor muscles of the thigh downwards to the tubercle of the tibia. It is, therefore, no ligament; and, as we have before stated, that the patella is simply a sesamoid bone, developed in the tendon of the 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 patellae, near its insertion. 4, 4. The synovial membrane. 5. The internaj .oteral ligament. 6. The long external lateral ligament. 7. The anterior supeiioj tbio- tibular 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 of the 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-cartilage, 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 two 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. 8. The tendon of the 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* h Fig. 94.f 1G2 KNEE JOINT. 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 of the 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- Fig. 95* 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 innei surface of the ligaments 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 tnents. 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 patella? turned down. 9. The bursa, situated between the ligamentum patetla? and the head of the tibia; it has been laid open. 10. The anterior superior tibio-fibular ligament. 11. The upper part of the interosseous membrane; the opening above this membrane is for the passage of the anterior tibial artery. ■j- A longitudinal section of the left knee joint, showing the reflection of its synovial membrane. 1. The cancellous structure of the lower part of the femur. 2. The tendon of the extensor muscles of the leg. 3. The patella. 4. The ligamentum patella?. 5. The cancellous structure of the head of the tibia. 6. A bursa situated between the ligamentum patella? 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 inent (10) ; then over the head of the tibia, forming a sheath to the crucial ligamenrs; then upwards along the posterior ligament and condyles of the femur to the sacouins, whence its examination commenced. TIBIO-FIBULAR ARTICULATIONS. 163 die folds in the interior of the 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. Between 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 patellae 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. Anterior, ) , Interosseous membrane, Posterior, ) ' Interosseous inferior, Anterior, ) , , Transverse. r, , • ' } below. Posterior, ) 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 proprius 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 .11 164 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 upcn th posterior surface of the articulation. Both ligaments project somewha below 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 of the synovial membrane of the 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. Fig. 96 * Fig. 97.f * An internal view of the ankle joint. 1. The internal malleolus of the tibia. 2, 2 Pait of the astragalus : the rest is concealed by the ligaments. 3. The os calcis. 4. The bcaphoid 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 of the external lateral ligament attached to the astragalus. 7. Its middle fasciculus, attached to the os calcis. 8. Its posterior fasciculus, attached to the astra gal us 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 bj 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 of the 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 onfy, without lateral motion. 5. Articulations of the 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-astragaloid, 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 between 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 of the 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 fibro-cartilaginous band of ligament, which passes forwards from the anterior and inner bor- der of the os calcis and scaphoid bone. In addition tn 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 plantae, 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 plantae, 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 twTo 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 backwards 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. 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 u, 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 articul* tion, like those of the articulation between the first phalanges and meta- carpal bones of the hand, are, Anterior or plantar, Two lateral, Transverse. • The ligaments of the sole of the foot. 1. The os calcis. 2. The astragalus. 3. Tne tuberosity of the scaphoid bone. 4. The long calcaneo-cuboid ligament. 5. Part of the Ehort calcaneo-cuboid ligament. 6. The calcaneo-scaphoid ligament. 7. The plantar tarsal ligaments. S, 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. 168 STRUCTURE OF MUSCLE. The anterior or plantar ligaments are thick and fibro-cartilaginous, and form part of the 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 of the metatarsal bones, are flexion, extension, adduction and abduc- tion. 8. Articulation of the 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 of the 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 tke 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 a tendon; and the union is so firm, that, under extreme violence, the bone itself rather breaks than permits of the separation of the tendon from its attachment. In the broad muscles the tendon is spread so as to form an expansion, called aponeurosis (o. subsequent examinations proved to be incorrect. Mr. Bowman employs the term " Sai- colemina," 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^, while that of the male is 3!5, the average of both being 4^3. The largest fibres are met with in fishes, in which animals they average 522 ; the next largest are found in man, while in other classes they range in the following order:—insects ?}g ; reptiles ^4; mammalia SJT; birds ff£7. 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 fibrillar. 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, fibriHae, 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 fas, iculus, there are transverse striae, showing divisions into discs, and longitudinal striae, 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. f 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 theii composition of ultimate fibrils. t An ultimate fibre, in which the transverse splitting into discs, in the direction of the constrictions of the ultimate fibrils is seen. From Mr. Bowman's paper. STRUCTURE OF MUSCLE. 171 102.* Fig. 1034 both surfaces, and containing, somewhere near the centre, one, two, or liree 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 fcetus, 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 of the 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 ^tjJuo" oi* an inch, and is composed of a suc- cession of cells connected by their flat surfaces. The cells are filled with a transparent substance, which I have termed myoline. The myoline differs in density in different cells, and from this circumstance bestows a peculiarity of character on certain of the cells; for example, when a fibril in its passive state is examined, there will be seen a series of dark oblong bodies se- parated by light spaces of equal length ; now the dark bodies are each composed of a pair of cells contain- ing the densest form of myoline, and are hence highly refractive while the transparent spaces are constituted by a pair of cells containing a more fluid myoline. When the fibrils are collected together so as to form an ultimate fibre or fasciculus, the appearance of the cell is altered; those which look dark in the single fibril, that is, the most refractive, being * Mass of ultimate fibres from the pectoralis major of the human fcetus, at nine months. These fibres have been immersed in a solution of tartaric acid, and their 'numerous corpuscles, turned in various directions, some presenting nucleoli," are shown. From Mr. Bowman's paper. ■j- These were made on dissections of fresh human muscle, prepared with great care by Mr. Lealand, partner of the eminent optician, Mr. Powell. $ Structure of the ultimate muscular fibril and fibre of animal life. a. An ultimate muscular fibril in the state of partial contraction. u. A similar fibril in the state of ordinary relaxation. This fibril measured -5—--^ of an inch in diameter. c. A similar fibril put upon the stretch, and measuring ^g-^^nr of an inch in diameter. n. Plan of a portion of an ultimate fibre, showing the manner in which the transverse strire are produced by the collocation of the fibrils. Nos. 1, 1. The pair of highly-refractive cells; they form the dark parts of the single fibrils, but the bright parts of the fibre d. In the stretched fibril c, each cell has the appearance of being double. 2, 2. The pair of less refractive cells, light in the single fibrils, but forming the shaded stria in d. The transverse septum between these cells is very conspicuous; and in c two other septa are seen to exist, making the number of transparent cells four. In n, the tier of cells immediately above the Tensor tarsi. Dissection. — The dissection of the face is to be effected by continuing' the longitudinal incision of the vertex of the previous dissection onwards to the tip of the nose, and thence downwards to the margin of the upper lip ; then carry an incision along the margin of the lip to the angle of the mouth, and transversely across the face to the angle of the lower jaw. Lastly, divide the integument in front of the external ear upwards to the transverse incision which was made for exposing the occipito-frontalis. Dissect the integument and superficial fascia carefully from the whole of the region included by these incisions, and the present with the two fol- lowing groups of muscles will be brought into view. The Orbicularis Palpebrarum is a sphincter muscle, surrounding the orbit and eyelids. It arises from the internal angular process of the frontal bone, from the nasal process of the superior maxillary, and from a short tendon (tendo oculi) which extends between the nasal process of the supe- rior maxillary bone, and the inner extremities of the tarsal cartilages of the eyelids. The fibres encircle the orbit and eyelids, forming a broad and thin muscular plane, which is inserted into the lower border of the tendo oculi, and into the nasal process of the superior maxillary bone. Upon the eyelids the fibres are thin and pale, and possess an involuntary action. The tendo oculi, in addition to its insertion into the nasal process of the superior maxillary bone, sends a process inwards which expands over the .achrymal sac, and is attached to the ridge of the lachrymal bone: this is the reflected aponeurosis of the tendo oculi. Relations.—By its superficial surface it is closely adherent to the integu- ment from which it is separated over the eyelids by a loose areolar tissue. By its deep surface it lies in contact above with the upper border of the orbit, with the corrugator supercilii muscle, and with the frontal and supra-orbital vessels and supra-orbital nerve; below, with the lachrymal sac, with the origins of the levator labii superioris alaeque nasi, levator labii superioris proprius, zygomaticus major and minor muscles, and malar bone ; and externally with the temporal fascia. Upon the eyelids it is in relation with the broad tarsal ligament and tarsal cartilages, and by its upper border gives attachment to the occipito-frontalis muscle. The Corrugator Supercilii is a small narrow and pointed muscle, situated immediately above the orbit and beneath the upper segment of the orbicularis palpebrarum muscle. It arises from the inner extremity of the superciliary ridge, and is inserted into the under surface of the orbi- cularis palpebrarum at a point corresponding with the middle of the super- ciliary arch. Relations.—By its superficial surface with the pyramidalis nasi, occipito frontalis and orbicularis palpebrarum muscle; and by its deep surface, with the supra-orbital vessels and nerve. 176 OCULAR GROUP. The Tensor Tarsi (Horner's* muscle) is a thin plane of muscular fibres, about three lines in breadth and six in length. It is best dissected by separating the eyelids from the eye, and turning them over the nose without. disturbing the tendo oculi; then dissect away the small fold of mucous membrane called plica semilunaris, and some loose cellular tissue under which the muscle is concealed. It arises from the orbital sur- face of the lachrymal bone, and passing across the lachrymal sac divides into two slips, which are inserted into the lachry- mal canals as far as the puncta. Actions. — The palpebral portion of the orbicularis acts involuntarily in closing the lids, and from the greater curve of the upper lid, upon that principally. The entire muscle acts as a sphincter, drawing at the same time, by means of its osseous attachment, the integument and lids inwards towards the nose. The corrugatores superciliorum draw the eyebrows downwards and inwards, and produce the vertical wrinkles of the fore- head. The tensor tarsi, or lachrymal muscle, draws the extremities of the lachrymal canals inwards, so as to place the puncta in the best posi- tion for receiving the tears. It serves also to keep the lids in relation with the surface of the eye, and compresses the lachrymal sac. Dr. Hor- ner is acquainted with two persons who have the voluntary power of drawing the lids inwards by these muscles so as to bury the puncta in the angle of the eye. 3. Ocular group.—Levator palpebral, Rectus superior, Rectus inferior, Rectus internus, Rectus externus, Obliquus superior, Obliquus inferior. Dissection.—To open the orbit (the calvarium and brain having been re- moved) the frontal bone must be sawn through at the inner extremity of the orbital ridge, and, externally, at its outer extremity. The roof of the or- bit may then be comminuted by a few light blows with the hammer ; a pro- cess easily accomplished, on account of the thinness of the orbital plate of the frontal bone and lesser wing of the • W. E. Horner, M. D., Professor of Anatomy in the University of Pennsylvania. The notice of this muscle is contained in a work published in Philadelphia in 1827, entitled •• Lessons in Practical Anatomy." f A view of the tensor tarsi muscle. 1, 1. Bony margins of the orbit. 2. Opening between the eyelids. 3. Internal face of the orbit. 4. Origin of the tensor tarsi. 5 5. Insertion into the neighbourhood of the puncta lachrymalis. i The muscles of the eyeball; the view is taken from the outer side of the right orbit 1. A small fragment of the sphenoid bone around the entrance of the optic nerve into Hi" orbit. 2. The optic nerve. 3. The globe of the eye. 4. The levator palpebras RECTUS EXTERNUS. 177 sphenoid. The superciliary portion of the orbit may now be driven for- wards by a smart blow, and the external angular process and external wall of the orbit outwards in the same manner; the broken fragments of the roof of the orbit should then be removed. By this means the perios- teum will be exposed unbroken and undisturbed. Remove the periosteum from the whole of the upper surface of the exposed orbit, and examine the parts beneath. The Levator Palpebrje is a long, thin, and triangular muscle ; situated in the upper part of the orbit on the middle line; it arises from the upper margin of the optic foramen, and from the fibrous sheath of the optic nerve, and is inserted into the upper border of the superior tarsal cartilage. Relations.—By its upper surface with the fourth nerve, the supra-orbital nerve and artery, the periosteum of the orbit, and in front with the inner surface of the broad tarsal ligament. By its under surface it rests upon the superior rectus muscle, and the globe of the eye; it receives its nerve and artery by this aspect, and in front is covered for a short distance by the conjunctiva. The Rectus Superior (attollens) arises from the upper margin of the optic foramen, and from the fibrous sheath of the optic nerve, and is in- serted into the upper surface of the globe of the eye at a point somewhat more than three lines from the margin of the cornea. Relations.—By its upper surface with the levator palpebrae muscle; by the under surface with the optic nerve, the ophthalmic artery and nasal nerve, from which it is separated by a layer of fascia and by the adipose tissue of the orbit, and in front with the globe of the eye, the tendon of* the superior oblique muscle being interposed. The Rectus Inferior (depressor) arises from the inferior margin of the optic foramen by a tendon (ligament of Zinn) which is common to it, the internal and the external rectus, and from the fibrous sheath of the optic nerve ; it is inserted into the inferior surface of the globe of the eye at a little more than two lines from the margin of the cornea. Relations.—By its upper surface with the optic nerve, the inferior oblique branch of the third nerve, the adipose tissue of the orbit, and the under surface of the globe of the eye. By its under surface with the periosteum of the floor of the orbit, and with the inferior oblique muscle. The Rectus Internus (adductor), the thickest and shortest of the straight muscles, arises from the common tendon, and from the fibrous sheath of the optic nerve; and is inserted into the inner surface of the globe of the eye at two lines from the margin of the cornea. Relations.—By its internal surface with the optic nerve, the adipose tissue of the orbit and the eyeball. By its outer surface with the perios- teum of the orbit; and by its upper border with the anterior and posterior ethmoidal vessels, the nasal and supra-trochlear nerve. The Rectus Externus (abductor), the longest of the straight muscles, arises by two distinct heads, one from the common tendon, the other with muscle. 5. The superior oblique muscle. 6. Its cartilaginous pulley. 7. Its reflected tendon. 8. The inferior oblique muscle; the small square knob at its commencement is a piece of its bony origin broken off. 9. The superior rectus. 10. The internal rectus almost concealed by the optic nerve. 11. Part of the external rectus, showing its two heads of origin. 12. The extremity of the external rectus at its insertion; the inter mediate portion of the muscle having been removed. 13. The inferior rectus. 14 The tunica albuginea, formed by the expansion of the tendons of the four recti. M 178 OBLIQUUS INFERIOR. the origin of the superior rectus from the margin of the optic foramen; the nasal, third and sixth nerves passing between its heads. It is inserted into the outer surface of the globe of the eye at a little more than two lines from the margin of the cornea. Relations.—By its internal surface with the third, the nasal, the sixth, and the optic nerve, the ciliary ganglion and nerves, the ophthalmic artery and vein, the adipose tissue of the orbit, the inferior oblique muscle and the eyeball. By its external surface with the periosteum of the orbit; and by the upper border with the lachrymal vessels and nerve and the lachry- mal gland. The recti muscles present several characters which are common to -all; thus they are thin, have each the form of an isosceles triangle, bear the same relation to the globe of the eye, and are inserted in a similar manner into the sclerotica, at about two lines from the circumference of the cornea. The points of difference relate to thickness and length; the internal rectus is the thickest and shortest, the external rectus the longest of the four, and the superior rectus the most thin. The insertion of the four recti muscles into the globe of the eye forms a tendinous expansion, which is continued as far as the margin of the cornea, and is called the tunica albuginea. The Obliquus Superior (trochlearis) is a fusiform muscle arising from the margin of the optic foramen, and from the fibrous sheath of the optic nerve ; it passes forwards to the pulley beneath the internal angular pro- cess of the frontal bone ; its tendon is then reflected beneath the superior rectus muscle, to the outer and posterior part of the globe of the eye, where it is inserted into the sclerotic coat, near the entrance of the optic nerve. The tendon is surrounded by a synovial membrane, while passing through the cartilaginous pulley. Relations. — By its superior surface with the fourth nerve, the supra- trochlear nerve, and with the periosteum of the orbit. By the inferior surface with the adipose tissue of the orbit, the upper border of the inter- nal rectus and the vessels and nerves in relation with that border. The Obliquus Inferior, a thin and narrow muscle, arises from the inner margin of the superior maxillary bone, immediately external to the lachrymal groove, and passes beneath the inferior rectus, to be inserted into the outer and posterior part of the eyeball, at about two lines from the entrance of the optic nerve. Relations. — By its superior surface with the inferior rectus muscle and with the eyeball; and by the inferior surface with the periosteum of the floor of the orbit, and the external rectus muscle. According to Mr. Farrall* the muscles of the orbit are separated from the globe of the eyeball and from the structures immediately surrounding the optic nerve, by a distinct fascia, which is continuous with the broad tarsal ligament and with the tarsal cartilages. This fascia the author terms the tunica vaginalis oculi,\ it is pierced anteriorly for the passage of the six orbital muscles, by six openings through which the tendons of the muscles play as through pulleys. The use assigned to it by Mr. Farrall is to protect the eyeball from the pressure of its muscles during their ac- tion. By means of this structure the recti muscles are enabled to impress * In a paper read before the Royal Society, on the 10th of June, 1841. \ This fascia was first described by Mr. Dalrymple in his work on the "Anatomy ol the Human Eye." 1834. NASAL GROUP. 179 a rotatory movement upon the eyeball; and in animals provided with a -etractor muscle, they also act as antagonists to its action. Actions.—The levator palpebrae raises the upper eyelid. The four recti, acting singly, pull the eyeball in the four directions ; upwards, downwards, inwards, and outwards. Acting by pairs, they carry the eyeball in the diagonal of these directions, viz. upwards and inwards, upwards and out- wards, downwards and inwards, or downwards and outwards. Acting all together, they directly retract the globe within the orbit. The superior oblique muscie, acting alone, rolls the globe inwards and forwards, and carries the pupil outwards and downwards to the lower and outer angle of the orbit. The inferior oblique, acting alone, rolls the globe outwards and backwards, and carries the pupil outwards and upwards to the upper and outer angle of the eye. Both muscles acting together, draw the eye- ball forwards, and give the pupil that slight degree of eversion which en- ables it to admit the largest field of vision. 4. Nasal Group.—Pyramidalis nasi, Compressor nasi, DilatetorTiaTis. The Pyramidalis Nasi is a small pyramidal slip of muscular fibres sent downwards upon the bridge of the nose by the occipito-frontalis. It is inserted into the tendinous expansion of the compressores nasi. Relations.—By its upper surface with the integument; by its under sur- face with the periosteum of the frontal and nasal bone. Its outer border corresponds with the edge of the orbicularis palpebrarum, and its inner border with its fellow, from which it is separated by a slight interval. The Compressor Nasi is a thin and triangular muscle ; it arises by its apex from the canine fossa of the superior maxillary bone, and spreads out upon the side of the nose into a thin tendinous expansion, which is con- tinuous across its ridge with the muscle of the opposite side. Relations. — By its superficial surface with the levator labii superioris proprius, the levator labii superioris alaeque nasi, and the integument; by its deep surface with the superior maxillary and nasal bone, and with the alar and lateral cartilages of the nose. The Dilatator Naris is a thin and indistinct muscular apparatus ex- panded upon the ala of the nostril, and consisting of an anterior and a posterior slip. The anterior slip (levator proprius alae nasi anterior) ex- tends between the lateral and alar cartilage at about midway between the tip and the attached margin of the nose. The posterior slip (levator pro- prius alae nasi posterior) is attached above to the margin of the nasal pro- cess of the superior maxillary bone, and below to the small cartilages of the ala nasi. These muscles are difficult of dissection from the close adherence of the integument to the nasal cartilages. Actions. — The pyramidalis nasi, as a point of attachment of the occi- pito-frontalis, assists that muscle in its action: it also draws down the inner angle of the eyebrow, and by its insertion fixes the aponeurosis of the compressores nasi. The compressores nasi appear to act in expanding rather than in compressing the nares; hence probably the compressed state of the nares from paralysis of these muscles in the last moments of life, or in compression of the brain. The use of the dilatator naris is ex pressed in its name. ISO SUPERIOR LABIAL GROUP. 5. Superior Labial Group.—forbicularis oris, (Levator labii superioris alaeque nasi, [Levator labii superioris proprius, (Levator anguli oris, Zygomaticus major, ■^Zygomaticus minor, Repressor labii superioris alaeque nasi. ; The Orbicularis Oris is a sphincter muscle, completely surrounding the mouth, and possessing consequently neither origin nor insertion. It is composed of two thick semicircular planes of fibres, which embrace the rima of the mouth, and interlace at their extremities, where they are con- tinuous with the fibres of the buccinator, and of the other muscles con- nected with the angle of the mouth. The upper segment is attached by means of a small muscular fasciculus (naso-labialis) to the columna of the nose ; and other fasciculi connected with both segments and attached to the maxillary bones are termed " accessorii." Relations.—By its superficial surface with the integument of the lips, with which it is closely connected. By its deep surface with the mucous membrane of the mouth, the labial glands and coronary arteries being interposed. By its circumference with the numerous muscles which move the lips, and by the inner border with the mucous membrane of the rima of the mouth. , The Levator Labii Superioris Al^que Nasi is a thin triangular piuscle : it arises from the upper part of the nasal process of the superior maxillary bone; and becoming broader as it descends, is inserted by two distinct portions into the ala of the nose and upper lip. Relations.—By its superficial surface with part of the orbicularis palpe- brarum muscle, the facial artery, and the integument. By its deep surface with the superior maxillary bone, compressor nasi, alar cartilage, and with a muscular fasciculus attached only to the bone, and thence called musculus anomalus. / The Levator Labii Superioris Proprius j> a thin quadrilateral mus- cle : it arises from the lower border of the orbit, and passing obliquely downwards and inwards, is inserted into the integument of the upper lip; its deep fibres being blended with those of the orbicularis. Relations.—By its superficial surface with the lower segment of the orbicularis palpebrarum, with the facial artery, and with the integument. By its deep surface with the origins of the compressor nasi and levator anguli oris muscle, and with the infra-orbital artery and nerve. The Levator Anguli Oris arises from the canine fossa of the superior maxillary bone, and passes outwards to be inserted into the angle of the mouth, intermingling its fibres with those of the orbicularis, zygomatici, and depressor anguli oris. Relations.—By its superficial surface with the levator labii superioris proprius, the branches of the infra-orbital artery and nerve, and inferiorly with the integument. By its deep surface with the superior maxillary bone and buccinator muscle. The Zygomatic muscles are two slender fasciculi of fibres which arise from the malar bone, and are inserted into the angle of the mouth, where they are continuous with the other muscles attached to this part. The zygomaticus minor is situated in front of the major, and is continuous at INFERIOR LABIAL GROUP. 181 its insertion with the levator labii superioris proprius; it is not unfre- quently wranting. Relations.—The zygomaticus major muscle is in relation by its superficial surface with the lower segment of the orbicularis palpebrarum above, and the fat of the cheek and integument for the rest of its extent. By its deep surface with the malar bone, the masseter, and buccinator muscle, and the facial vessels. The zygomaticus minor, being in front of the major, has no relation with the masseter muscle, while inferiorly it rests upon the evator anguli oris. /The Depressor Labii Superioris Aljeque Nasi (myrtiformis) is seen by drawing upwards the upper lip, and raising the mucous membrane. It is a small oval slip of muscle, situated on each side of the fraenum, arising from the incisive fossa, and passing upwards to be inserted into the upper lip and into the ala and columna of the nose. This muscle is continuous by its outer border with the edge of the compressor nasi. Relations.—By its superficial surface with the mucous membrane of the mouth, the orbicularis oris and levator labii superioris alaeque nasi muscle; and by its deep surface with the superior maxillary bone. Actions.—The orbicularis oris produces the direct closure of the lips by means of its continuity at the angles of the mouth with the fibres of the buccinator. When acting singly in the forcible closure of the mouth, the integument is thrown into wrinkles in consequence of its firm connexion with the surface of the muscle. The levator labii superioris alaeque nasi lifts the upper lip with the ala of the nose, and expands the opening of the nares. The depressor labii superioris alaeque nasi is the antagonist to this muscle, drawing the upper lip and ala of the nose downwards, and con- tracting the opening of the nares. The levator labii superioris proprius is the proper elevator of the upper lip ; acting singly it draws the lip a little to one side. The levator anguli oris lifts the angle of the mouth and draws it inwards, while the zygomatic pull it upwards and outwards, as in laughing. 6. Inferior Labial Group.---Depressor labii inferioris, ('Depressor anguli oris, I Levator labii inferioris. Dissection.—To dissect the inferior labial region continue the vertical section from the margin of the lower lip to the point of the chin. Then carry an incision along the margin of the lower jaw to its angle. Dissect off the integument and superficial fascia from the whole of this surface, and the muscles of the inferior labial region will be exposed. / The Depressor Labii Inferioris (quadratus menti) arises from the oblique line by the side of the symphysis of the lower jaw, and passing upwards and inwards is inserted into the orbicularis muscle and integu- ment of the lower lip. Relations.—By its superficial surface with the platysma myoides, part of the depressor anguli oris, and with the integument of the chin, with which it is closely connected. By the deep surface with the levator labii inferioris, the labial glands and mucous membrane of the lower lip, and with the mental nerve and artery. The Depressor Anguli Oris (triangularis oris) is a triangular plane of muscle arising by a broad base from the external oblique ridge of the 16 182 MAXILLARY GROUP. lower jaw, and inserted by its apex into the angle of the moutli, where it is continuous with the levator anguli oris and zygomaticus major. Relations.—By its superficial surface with the integument; and by its deep surface with the depressor labii inferioris, the buccinator, and tne branches of the mental nerve and artery. ((iThe Levator Labii Inferioris (levator menti) is a small conical slip of muscle arising from the incisive fossa of the lower jaw, and inserted into the integument of the chin. It is in relation with the mucous mem- brane of the mouth, with its fellow, and with the depressor labii inferioris. Actions. — The depressor labii inferioris draws the lower lip directly downwards, and at the same time a little outwards. The depressor an- guli oris, from the radiate direction of its fibres, will pull the angle of the mouth either downwards and inwards, or downwards and outwards, and be expressive of grief; or acting with the levator anguli oris and zygo- maticus major, it will draw the angle of the mouth directly backwards. The levator labii inferioris raises and protrudes the integument of the chin. 7. Maxillary group.—(Masseter, /Temporalis, (Buccinator, Pterygoideus externus, Pterygoideus internus. Dissection.—The masseter has been already exposed by the preceding dissection. / The Masseter ((xafftfao/xai, to chew,) is a short, thick, and sometimes quadrilateral muscle, composed of two planes of fibres, superficial and deep. The superficial layer arises by a strong aponeurosis from the tuberosity of the superior maxillary bone, the lower border of the malar bone and zygoma, and passes backwards to be inserted into the ramus and angle of the inferior maxilla. The deep layer arises from the poste- rior part of the zygoma, and passes forwards, to be inserted into the upper half of the ramus. This muscle is tendinous and muscular in its structure. Relations.—By its external surface with the zygomaticus major and risorius Santorini muscle, the parotid gland and Stenon's duct, the trans- verse facial artery, the pes anserinus and the integument. By its internal surface with the temporal muscle, the buccinator, from which it is separated by a mass of fat, and with the ramus of the lower jaw. By its posterior border with the parotid gland; and by the anterior border with the facial artery and vein. Dissection. — Make an incision along the upper border of the zygoma, for the purpose of separating the temporal fascia from its attachment. Then saw through the zygomatic process of the malar bone, and through the root of the zygoma, near to the meatus auditorius. Draw down the zygoma, and with it the origin of the masseter, and dissect the latter muscle away from the ramus and angle of the inferior maxilla. Now re- move the temporal fascia from the rest of its attachment, and the whole of the temporal muscle will be exposed. ^The Temporal is a broad and radiating muscle occupying a considera- ble extent of the side of the head and filling the temporal fossa. It is covered in by a very dense fascia (temporal fascia) which is attached along BUCCINATOR—PTERYGOIDEI. 183 the temporal ridge on the side of the skull, extending from the external angular process of the frontal bone to the mastoid portion of the temporal; inferiorly, it is connected to the upper border of the zygoma. The muscle arises by tendinous fibres from the whole length of the temporal ridge, and by muscular fibres from the temporal fascia and entire surface of the temporal fossa. Its fibres converge to a strong and narrow7 tendon, which is inserted into the apex of the coronoid process, and for some way down upon its inner surface. Relations. — By its external surface with the temporal fascia, which se- parates it from the attollens and attrahens aurem muscle, the temporal vessels and nerves ; and with the zygoma and masseter. By its internal surface with the bones forming the temporal fossa, the external pterygoid muscle, a part of the buccinator, and the internal maxillary artery with its deep temporal branches. By sawing through the coronoid process near to its base, and pulling it upwards, together with the temporal muscle, which may be dissected from the fossa, we obtain a view of the entire extent of the buccinator and of the external pterygoid muscle. /The Buccinator (buccina, a trumpet), the trumpeter's muscle, arises from the alveolar process of the superior maxillary and from the external oblique line of the inferior maxillary bone, as far forward as the second bicuspid tooth, and from the pterygo-maxillary ligament. This ligament is the raphe of union between the buccinator and superior constrictor muscle, and is attached by one extremity to the hamular process of the internal pterygoid plate, and by the other to the extremity of the molar ridge. The fibres of the muscle converge towards the angle of the mouth where they cross each other, the superior being continuous with the infe- rior segment of the orbicularis oris, and the inferior with the superior segment. The muscle is invested externally by a thin fascia. Relations.—By its external surface, posteriorly with a large and rounded mass of fat, which separates the muscle from the ramus of the lower jaw, the temporal, and the masseter; anteriorly with the risorius Santorini, the zygomatici, the levator anguli oris, and the depressor anguli oris. It is also in relation with a part of Stenon's duct, which pierces it opposite the second molar tooth of the upper jaw, with the transverse facial artery, the branches of the facial and buccal nerve, and the facial artery and vein. By its internal surface with the buccal glands and mucous membrane of the mouth. The External Pterygoid is a short and thick muscle, broader at its origin than at its insertion. It arises by two heads, one from the pterygoid ridge on the greater ala of the sphenoid; the other from the external pterygoid plate and tuberosity of the palate bone. The fibres pass back- wards, to be inserted into the neck of the lower jaw and the interarticular fibro-cartilage. The internal maxillary artery frequently passes between the two heads of this muscle. Relations. — By its external surface, with the ramus of the lower jaw, the temporal muscle, and the internal maxillary artery; by its internal surface, with the internal pterygoid muscle, internal lateral ligament of the lower jaw, arteria meningea media, and inferior maxillary nerve ; and by its upper border, with the muscular branches of the inferior maxillary nerve ; the internal maxillary artery passes between the two heads of this muscle, ani i*s lower origin is pierced by the buccal nerve. ].84 AURICULAR GROUP. The external pterygoid muscle must now be removed, the ramus of the lower jaw sawn through its lower third, and the head of the bone dislo cated from its socket and withdrawn, for the purpose of seeing the ptery goideus internus. The Internal Pterygoid is a thick quadrangular muscle. It arises from the pterygoid fossa, and descends obliquely backwards, to be in- serted into the" ramus and angle of the lower jaw: it resembles the masse- ter in appearance and direction, and was named by Winslow the internal masseter. Relations.—By its external surface, with the external pterygoid, the in- ferior maxillary nerve and its branches, the internal maxillary artery and branches, the internal lateral ligament, and the ramus of the lower jaw By its internal surface, with the tensor palati, superior constrictor ana fascia of the pharynx; and by its posterior border, with the parotid gland. Actions.—The maxillary muscles are the Fig. 108* active agents in mastication, and form an ap- paratus beautifully fitted for that office. The buccinator circumscribes the cavity of the mouth, and with the aid of the tongue, keeps the food under the immediate pressure of the teeth. By means of its connexion with the superior constrictor, it shortens the cavity of the pharynx from before backwards, and be- comes an important auxiliary in deglutition. The temporal, the masseter, and the internal pterygoid, are the bruising muscles, drawing the lowrer jaw against the upper with great force. The two latter, by the obliquity of their direction, assist the ex- ternal pterygoid in grinding the food, by carrying the lower jawr forward upon the upper; the jaw being brought back again by the deep portion of the masseter and posterior fibres of the temporal. The whole of these muscles, acting in succession, produce a rotatory movement of the teeth upon each other, which, with the direct action of the lower jaw against the upper, effects the proper mastication of the food. 8. Auricular Group.—Attollens aurem, Attrahens aurem, Retrahens aurem. Dissection.—The three small muscles of the ear may be exposed by removing a square of integument from around the auricula. This opera- tion must be performed with care, otherwise the muscles, which are ex tremely thin, will be raised with the superficial fascia. They are best dissected by commencing with their tendons, and thence proceeding in the course of their radiating fibres. The Attollens aurem (superior auris), the largest of the three, is a thin triangular plane of muscular fibres arising from the edge of the aponeurosis of the occipito-frontalis, and inserted into the upper part of the concha. It is in relation by its external surface with the integument, and by the internal with the temporal aponeurosis. * The two pterygoid muscles. The zygomatic arch and the greater part of the ramus uf the lower jaw have been removed, in order to bring these muscles into view. i. The spheroid origin of the external pterygoid muscle. 2. Its pterygoid origin. 3. The internal pterygoid mus&e. MUSCLES OF THE NECK. 185 The Attrahens Aurem (anterior auris), also triangular, arises from the edge of the aponeurosis of the occipito-frontalis, and is inserted into the anterior part of the helix, covering in the anterior and posterior tem- poral arteries. It is in relation by its external surface with the integument; and by the internal with the temporal aponeurosis and with the temporal artery and veins. The Retrahens Aurem (posterior auris), arises by three or four mus- cular slips from the mastoid process. They are inserted into the posterior surface of the concha. It is in relation by its external surface with the integument, and by its internal surface with the mastoid portion of the temporal bone. Actions.—The muscles of the auricular region possess but little action in man; they are the analogues of important muscles in brutes. Their use is sufficiently explained in their names. MUSCLES OF THE NECK. The muscles of the neck may be arranged into eight groups correspond- ing with the natural divisions of the region; they are the— 1. Superficial group. 2. Depressors of the os hyoides and larynx. 3. Elevators of the os hyoides and larynx. 4. Lingual group. 5. Pharyngeal group. 6. Soft palate group. 7. Praevertebral group. 8. Proper muscles of the larynx. And each of these groups consist of the following muscles:— viz. 1. Superficial Group. Stylo-glossus, Platysma-myoides, Palato-glossus. Sterno-cleido-mastoideus. 5. Muscles of the Pharynx. 2. Depressors of the os hyoides Constrictor inferior, and larynx. Constrictor medius, Sterno-hyoideus, Constrictor superior, Sterno-thyroideus, Stylo-pharyngeus, Thyro-hyoideus, Palato-pharyngeus. Omo-hyoideus. 6. Muscles of the soft Palate. 3. Elevators of the os hyoides Levator palati, and larynx. Tensor palati, Digastricus, Azygos uvulae, Stylo-hyoideus, Palato-glossus, Mylo-hyoideus, Palato-pharyngeus. Genio-hyoideus, Genio-hyo-glossus. 7. Praevertebral Group. Rectus anticus major, 4. Muscles of the Tongue. Rectus anticus minor, Genio-hyo-glossus, Scalenus anticus, Hyo-glossus, Scalenus posticus, Lingualis, Longus colli. 16* 186 PLATYSMA MYOIDES. 8 Muscles of the Larynx. Crico-arytsenoideus, lateralis, Crico-thyroideus, Thyro-arytaenoideus. Crico-arytaenoideus, posticus, Arytaenoideus. Dissection.—The dissection of the neck should be commenced b) making an incision along the middle line of its fore part from the chin to the sternum, and bounding it superiorly and inferiorly by two transverse incisions; the superior one being carried along the margin of the lower jaw, and across the mastoid process to the tubercle on the occipital bone, the inferior one along the clavicle to the acromion process. The square flap of integument thus included should be turned back from the entire side of the neck, which brings into view the superficial fascia, and on the removal of a thin layer of superficial fascia the platysma myoides will be exposed. The Platysma Myoides (TrXarvg, p.vg siSog, broad muscle-like lamella), is a thin plane of muscular fibres, situated between the two layers of the superficial cervical fascia; it arises from the integument over the pectoralis major and deltoid muscles, and passes obliquely upwards and inwards along the side of the neck to be inserted into the side of the chin, oblique line of the lower jaw, the angle of the mouth, and into the cellular tissue of the face. The most anterior fibres are continuous beneath the chin, with the muscle of the opposite side ; the next interlace with the depressor anguli oris, and depressor labii inferioris, and the most posterior fibres are disposed in a transverse direction across the side of the face, arising in the cellular tissue covering the parotid gland, and inserted into the angle of the mouth, constituting the risorius Santorini. The entire muscle is ana- logous to the cutaneous muscle of brutes, the panniculus carnosus. Relations.—By its external surface with the integument, with which it is closely adhe- rent below, but loosely above. By its internal surface, below the clavicle, with the pectoralis major and deltoid; in the neck, with the external jugular vein and deep cervical fascia; on the face, with the parotid gland, the masseter, the facial artery and vein, the buccinator, the depressor anguli oris, and the depressor labii inferioris. On raising the platysma throughout its whole extent, the sterno-mastoid is brought into view. The Sterno-cleido-mastoid is the large oblique muscle of *The muscles of the anterior aspect of the neck; on the left side the superficial mus- cles are seen, and on the right the deep. 1. The posterior belly of the digastricus mus- cle. 2. Its anterior belly. The aponeurotic pulley, through which its tendon is seen passing, is attached to the body of the os hyoides. 3, 4. The stylo-hyoideus muscle transfixed by the posterior belly of the digastricus. 5. The mylo-hyoideus. 6. The Fig. 109* DEPRESSORS OP THE OS HYOIDES AND LARYNX. 187 the neck, and is situated between two layers of the deep cervical fascia It arises, as implied in its name, from the sternum and clavicle (xAeioVov), and passes obliquely upwards and backwards to be inserted into the mas- toid process and into the superior curved line of the occipital bone. The sternal portion arises by a rounded tendon, increases in breadth as it ascends, and spreads out to a considerable extent at its insertion. The clavicular portion is broad and fleshy, and separate from the sternal portion below, but becomes gradually blended with its posterior surface as it ascends. Relations.—By its superficial surface with the integument, the platysma myoides, the external jugular vein, superficial branches of the anterior cervical plexus of nerves, and the anterior layer of the deep cervical fascia. By its deep surface with the deep layer of the cervical fascia; with the sterno-clavicular articulation, the sterno-hyoid, sterno-thyroid, omo-hyoid, scaleni, levator anguli scapulae, splenii, and the posterior belly of the di- gastric muscle; with the phrenic nerve, and the posterior, and supra-sca- pular artery; with the deep lymphatic glands, the sheath of the common carotid and internal jugular vein, the descendens noni nerve, the external carotid artery and its posterior branches, the commencement of the internal carotid artery; with the cervical plexus of nerves, the pneumogastric, the spinal accessory, the hypoglossal, the sympathetic and the facial nerve, and with the parotid gland. It is pierced on this aspect by the spinal ac- cessory nerve and by the branches of the mastoid artery. The anterior border of the muscle is the posterior boundary of the great anterior triangle, the other two boundaries being the middle line of the neck in front, and the lower border of the jaw above. It is the guide to the operations for the ligature of the common carotid artery and arteria innominata, and for uesophagotomy. The posterior border is the anterior boundary of the great posterior triangle ; the other two boundaries being the anterior border of the trapezius behind, and the clavicle below. Actions.—The platysma produces a muscular traction on the integu- ment of the neck, which prevents it from falling so flaccid in old persons as would be the case if the extension of the skin were the mere result of elasticity. It draws also upon the angle of the mouth, and is one of the depressors of the lower jaw. The transverse fibres draw the angle of the mouth outwards and slightly upwards. The sterno-mastoid muscles are the great anterior muscles of connexion between the thorax and the head. Both muscles acting together bow the head directly forwards. The cla- vicular portions, acting more forcibly than the sternal, give stability and steadiness to the head in supporting great weights. Either muscle acting singly would draw the head towards the shoulder of the same side, and carry the face towards the opposite side. Second Group.—Depressors of the Os Hyoides and Larynx. Sterno-hyoid, Thyro-hyoid, Sterno-thyroid, Omo-hyoid. genio-hyoideus. 7. The tongue. 8. The hyo-glossus. 9. The stylo-glossus. 10. The stylo-pharyngeus. 11. The sterno-mastoid muscle. 12. Its sternal origin. 13. Its cla vicular origin. 14. The sterno-hyoid. 15. The sterno-thyroid of the right side. 16. The thyro-hyoid. 17. The hyoid portion of the omo-hyoid. 18, 18. Its scapular portion t on the left side, the tendon of the muscle is seen to be bound down by a portion of the deep cervical fascia. 19. The clavicular portion of the trapezius. 20. The scalenui anticus of the right side. 21. The scalenus posticus. 188 DEPRESSORS OF THE OS HYOIDES AND LARYNX. Dissection.—These muscles are brought into view by removing the «leep fascia from off the front of the neck between the two sterno-mastoid muscles. The omo-hyoid to be seen in its whole extent requires that the sterno-mastoid muscle should be divided from its origin and turned aside. The Sterno-hyoideus is a narrow riband-like muscle, arising from the posterior surface of the first bone of the sternum and inner extremity of the clavicle. It is inserted into the lower border and posterior surface of the body of the os hyoides. The sterno-hyoidei are separated by a con- siderable interval at the root of the neck, but approach each other as they ascend: they are frequently traversed by a tendinous intersection. Relations.—By its external surface with the deep cervical fascia, the platysma myoides and sterno-mastoid muscle; by its internal surface with the sterno-thyroid, and thyro-hyoid muscle, and the superior thyroid artery. The Sterno-thyroideus, broader than the preceding beneath which it lies, arises from the posterior surface of the upper bone of the sternum, and from the cartilage of the first rib ; it is inserted into the oblique line on the great ala of the thyroid cartilage. The inner borders of these muscles lie in contact along the middle line, and they are generally marked by a tendinous intersection at their lower part. Relations.—By its external surface with the sterno-hyoid, omo-hyoid, and sterno-mastoid muscle ; by its internal surface, with the trachea and inferior thyroid veins, with the thyroid gland, the lower part of the larynx, the sheath of the common carotid artery and internal jugular vein, with the subclavian vein and vena innominata and on the right side with the arteria innominata. The middle thyroid vein lies along its inner border. The Thyro-hyoideus is the continuation upwards of the sterno-thyroid muscle. It arises from the oblique line on the thyroid cartilage, and is inserted into the 'lower border of the body and great cornu of the os hyoides. Relations.—By its external surface with the sterno-hyoid and omo-hyoid muscle; by its internal surface with the great ala of the thyroid cartilage, the thyro-hyoidean membrane, and the superior laryngeal artery and nerve. The Omo-hyoideus (oV°r, shoulder) is a double-bellied muscle passing obliquely across the neck from the scapula to the os hyoides: it forms an obtuse angle behind the sterno-mastoid muscle, and is retained in that position by means of a process of the deep cervical fascia which is con- nected to the inner border of its tendon. It arises from the upper border of the scapula, and from the transverse ligament of the supra-scapular notch, and is inserted into the lower border of the body of the os hyoides. Relations.—By its superficial surface with the trapezius, the subclavius and clavicle, the deep cervical fascia and platysma myoides, the sterno- mastoid, and the integument. By its deep surface with the brachial plexus, the scaleni muscles, the phrenic nerve, the sheath of the common carotid artery and jugular vein, the descendens noni nerve, the sterno-thyroid, and thyro-hyoid muscle, and the sterno-hyoid at its insertion. The sca- pular portion cf the muscle divides the great posterior triangle into a su- perior or occipital triangle ; and an inferior or subclavian triangle, which contains the subclavian artery and brachial plexus of nerves; the other two boundaries of the latter being the sterno-mastoid in front and the cla- vicle below. The hyoid portion of the muscle divides the great anterior ELEVATORS OF THE OS HYOIDES. 189 triangle into an inferior carotid triangle situated below the muscle, and into a superior triangle which lies above the muscle and is again subdi- vided by the digastricus into the submaxillary triangle and the superior carotid, triangle. The other two boundaries of the inferior carotid triangle, are the middle line of the neck in front and the anterior border of the sterno-mastoid behind. The other boundaries of the superior carotid tri- angle are the posterior belly of the digastricus muscle above and the an- terior border of the sterno-mastoid behind. Actions.—The four muscles of this group are the depressors of the os hyoides and larynx. The three former drawing these parts downwards in the middle line, and the two omo-hyoidei regulating their traction to the one or other side of the neck, according to the position of the head. The omo-hyoid muscles by means of their connexion with the cervical fascia are rendered tensors of that portion of the deep cervical fascia which covers in the lower part of the neck, between the two sterno-mastoid muscles. Third Group.—Elevators of the Os Hyoides. Digastricus, Genio-hyoid, Stylo-hyoid, Genio-hyo-glossus. Mylo-hyoid, Dissection. — These are best dissected by placing a high block beneath the neck, and throwing the head backwards. The integument has been already dissected away, and the removal of the cellular tissue and fat brings them clearly into view. The Digastricus (5!g, twice, yatf-n^, belly) is a small muscle situated immediately beneath the side of the body of the lower jaw; it is fleshy at each extremity, and tendinous in the middle. It arises from the digastric fossa, upon the inner side of the mastoid process of the temporal bone, and is inserted into a depression on the inner side of the lower jaw, close to the symphysis. The middle tendon is held in connexion with the body of the os hyoides by an aponeurotic loop, through which it plays as through a pulley; the loop being lubricated by a synovial membrane. A thin layer of aponeurosis is given off from the tendon of the digastricus at each side, which is connected with the body of the os hyoides, and forms a strong plane of fascia between the anterior portions of the two muscles. This fascia is called the supra-hyoidean. Relations. — By its superficial surface with the platysma myoides, the sterno-mastoid, the anterior fasciculus of the stylo-hyoid muscle, the parotid gland, and submaxillary gland. By its deep surface with the styloid muscles, the hyo-glossus, the mylo-hyoid muscle, the external carotid artery, the lingual and the facial arteries, the internal carotid artery, the jugular vein, and the hypoglossal nerve. The digastric muscle forms the two inferior boundaries of the submaxillary triangle, the superior boun- dary being the side of the body of the lower jaw. In the posterior half of the submaxillary triangle are situated the submaxillary gland and the facial artery. The Stylo-hyoideus is a small and slender muscle situated in imme- diate relation with the posterior belly of the digastricus muscle, being pierced by its tendon. It arises from the middle of the styloid process, and is insetted into the body of the os hyoides near the middle line. 190 MYLO-HYOIDEUS--GENIO-HYOIDEUS. Relations. — By its superficial surface with the posterior belly of the digastricus, the parotid gland and submaxillary gland ; its deep relations are similar to those of the posterior belly of the digastricus. The digastricus and stylo-hyoideus must be removed from their con- nexion with the lower jaw and os hyoides, and turned aside in order to see the next muscle. The Mylo-hyoideus (fxuXrj, 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 awray 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 (ysvsov, 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 of the body of the os hyoides. It is a short and slender muscle, very closely connected with the border of the following. 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 (yXuada, 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 of the 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 Hyo-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, *o 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 of the 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. 13. The thyro-hyoidean membrane. 14. The thyroid cartilage. 15. The thyro-hyoideus muscle arising from the oblique line on the thyroid cartilage. 16. The cricoid cartilage. 17. The crico-thyroidean membrane, through which the ope- ration of laryngotomy is performed. 18. The trachea. 19. The commencement of tL" u^ophagus. 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 transverse 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 of the 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 of the 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 power of closing the fauces com pletely, an action which takes place in deglutition. Fifth Group.—Muscles of the Pharynx. Constrictor inferior, Constrictor medius, Constrictor superior, Stylo-pharyngeus, Palato-pharyngeus. Dissection.—To dissect the pharynx, the trachea and oesophagus are to )e 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 tow 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 ihe 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 of the 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- pharyngeal 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 17 N 194 MUSCLES OF THE SOFT PALATE. Pic, 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 upwrards, and with the aid of the uvula close the opening of the fauces. Sixth Group.—Muscles of the 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-maxil'ary liga- ment. 15. The buccinator muscle. 16. The orbicularis oris. 17. The mylo-hyoideus. PALATO-GLOSSUS—PA LATO-PHARYNGEUS. 195 This muscle must be turned down from Fig. 112* 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 of the Eustachian tube. It descends to the hamular process, around wrhich it turns and expands into a tendinous aponeu- rosis, which is inserted into the transverse ridge on 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 UvuL.as 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 of the soft palate. They arise from the spine of the 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 of the tongue. It is the projection of this small muscle, covered b\ 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- mular process of the internal pterygoid plate of the 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. 8. The azygos uvula? muscle. 9. The internal pterygoid plate. 10. The external pterygoid plate. 11. The tensor pa- lati muscle. 12. Its aponeurosis expanding in the structure of the soft palate. 13. The external pterygoid muscle. 14. The attachments of two pairs of muscles cut short; the superior pair belong to the genio-hyo-glossi muscles; the inferior pair to the genio- hyoidei. 15. The attachment of the mylo-hyoideus of one side and part of the opposite. 16. The anterior attachments of the 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 trwo-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, wihie 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 of the 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.—Praevertebral 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 which 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 upwards 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 of the 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 of the 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. 197 113.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 two 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 ( 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 1841 by Mr. Joseph Rogers, the subclavian artery of the left side was placed with the vein in front of the scalenus anticus muscle. \ The prevertebral group of muscles of the 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* J 98 MUSCLES OF THE BACK. processes of the five superior cervical vertebrae above, and to the boaies of the 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 vertebra. 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 of the 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 of the Back.—The region of the 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 maybe arranged into six layers. First Layer. (Cervical Group.) r^ . Cervicalis ascendens, _ P . ' _ Trcmet'Arecilie r>r»lli Latissimus dorsi. Transversalis colli, Trachelo- m astoideus, Second Layer. Complexus. r ... Fifth Layer. Levator anguli scapulae, ._ ^ , _ Rhomboideus minor, _ . (Dorsal Group.) Rhomboideus major. Semi-sp.na is dorsi, Semi-spinalis colli. Third Layer. _, (Cervical Group.) Rectus posticus major, Serratus posticus superior, Rectus posticus minor, Serratus posticus inferior, Rectus lateralis, Splenius capitis, Obliquus inferior, Splenius colli. Obliquus superior. „ ., T Sixth Layer. fourth Layer. ,, ,.,,, . J a 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 alonp- 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 aero 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 spinae, 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 nuchae is a thin cellulo-fibrous layer extended from tht 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 renin! 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 hack and loins. It arises from the spinous processes of the seven inferior dorsal vertebrae, from all the lumbar an.d sacral spinous processes, from the posterior third of the crest of the ilium, and from the three lower ribs; tht* 200 MUSCLES OF THE BACK. latter origin takes place by muscular slips, which indigitate with the ex- ternal oblique muscle of the abdomen. The fibres from this extensive Fig. 114.* origin converge as they ascend, and cross the inferior angle of the scapula; they then curve 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 muscle. 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 acromicn process and spine of the scapula. 4. The latissimus dorsi muscle. 5. The deltoid. 6. Tho muscles of the dorsum of the scapula, infra-spinatus, teres minor, and teres major. 7. The external oblique muscle. 8. The gluteus medius. 9. The glutei maximi. 10. The levator anguli scapulae. 11. The rhomboideus minor. 12. The rhomboideus major. 13. The splenius capitis ; the muscle immediately above, and overlaid by the splenius, is the complexus. 14. The splenius colli, only partially seen; the common origin of the splenius is seen attached to the spinous processes below the lower border of the rhom- boideus major. 15. The vertebral aponeurosis. 16. The serratus posticus inferior. 17. The supra-spinatus muscle. 18. The infra-spinatus. 19. The teres minor muscle. 20. The teres major. 21. The long head of the triceps, passing between the teres minor ind major to the upper arm. 22. The serratus magnus, proceeding forwards from its origin at the base of the scapula. 23. The internal oblique muscle. | A small muscular fasciculus from the pectoralis major is sometimes found connected with 'his tendon. MUSCLES OF THE BACK. 201 another between its tendon and that of the teres major. The muscle fre- quently receives a small fasciculus from the scapula as it crosses its inferior angle. Relations.—By its superficial surface with the integument and superficial fascia; the latter is very dense and fibrous in the lumbar region; and with the trapezius. By its deep surface from below upwards, with the erector spinae, serratus posticus inferior, intercostal muscles and ribs, rhomboideus major, inferior angle of the scapula and teres major. The latissimus dorsi, with the teres major, forms the posterior border of the axilla. Second Layer. Dissection.—This layer is brought into view by dividing the two pre- ceding muscles near their insertion, and turning them to the opposite side. The Levator Anguli Scapula arises by distinct slips, from the posterior tubercles of the transverse processes of the four upper cervical vertebrae, and is inserted into the upper angle and posterior border of the scapula, as far as the triangular smooth surface at the root of its spine. Relations.—By its superficial surface with the trapezius, sterno-mastoid and integument. By its deep surface with the splenius colli, transversalis colli, cervicalis ascendens, scalenus posticus, and serratus posticus supe- rior. The tendons of origin are interposed between the attachments of the scalenus posticus in front, and the splenius colli behind. The Rhomboideus Minor (rhombus, a parallelogram with four equal sides) is a narrow slip of muscle, detached from the rhomboideus major by a slight cellular interspace. It arises from the spinous process of the two last cervical vertebrae and ligamentum nuchae, and is inserted into the edge of the triangular surface, on the posterior border of the scapula. The Rhomboideus Major arises from the spinous processes of the last cervical and four upper dorsal vertebrae and from the inter-spinous liga- ments ; it is inserted into the posterior border of the scapula as far as its inferior angle. The upper and middle portion of the insertion is effected by means of a tendinous band which is attached in a longitudinal direction to the posterior border of the scapula. Relations.—By their superficial surface the two rhomboid muscles are in relation with the trapezius, and the rhomboideus major with the latis- simus dorsi and integument. By their deep surface they cover in the ser- ratus posticus superior, part of the erector spince, the intercostal muscles and ribs. Third Layer. Dissection.—The third layer consists of muscles which arise from the spinous processes of the vertebral column, and pass outwards. It is brought into view by dividing the levator anguli scapulae near its insertion, and reflecting the two rhomboid muscles upwards from their insertion into the scapula. The latter muscles should now be removed. The Skrratus Posticus Superior is situated at the upper part of the thorax ; it arises by the ligamentum nuchae, from the spinous processes of the three last cervical and those of the two upper dorsal vertebrae. The muscle passes obliquely downwards, and outwards, and is inserted by four 202 MUSCLES OF THE BACK. serrations into the upper border of the second, third, fourth, and fifth ribs. Relations.—By its superficial surface with the trapezius, rhomboideus major and minor, and serratus magnus. By its deep surface with the splenius, the upper part of the erector spinae, the intercostal muscles and ribs. The Serratus Posticus Inferior arises from the processes and inter- spinous ligaments of the two last dorsal and three upper lumbar vertebrae, and passing obliquely upwards is inserted by four serrations into the lower border of the four lower ribs. Both muscles are constituted by a thin aponeurosis for about half their extent. Relations.—By its superficial surface with the latissimus dorsi, its tendi- nous origin being inseparably connected with the aponeurosis of that muscle. By its deep surface with the aponeurosis of the obliquus internus, with which it is also closely adherent; with the erector spinae, the intercostal muscles and lower ribs. The upper border is continuous with a thin ten- dinous layer, the vertebral aponeurosis. The Vertebral aponeurosis is a thin membranous expansion composed of longitudinal and transverse fibres, and extending the whole length of the thoracic region. It is at- tached mesially to the spinous processes of the dorsal vertebrae, and exter- nally to the angles of the ribs; superiorly it is continued upwards beneath the serratus posticus superior, with the lower border of which it is some- times connected. It serves to bind down the erector spinae, and separate it from the superficial muscles. The serratus posticus superior must be removed from its origin and turned outwards, to bring into view the wiiole extent of the splenius muscle. The Splenius Muscle is single at its origin, but divides soon after into two portions, which are destined to distinct insertions. It arises by the lower half of the ligamentum nuchae, from the spinous processes of the five last cervical, and from the spinous processes and interspinous liga- ments of the six upper dorsal vertebrae ; it divides as it ascends the neck into the splenius capitis and colli. The splenius capitis is inserted into the rough surface of the occipital bone between the two curved lines, and into the mastoid portion of the temporal bone. The splenius colli is inserted into the posterior tubercles of the trans- verse processes of the three or four upper cervical vertebrae. Relations.—By its superficial surface with the trapezius, sterno-mastoid, levator anguli scapulae, rhomboideus minor and major, and serratus pos- ticus superior. By its deep surface with the spinalis dorsi, longissimus dorsi, semi-spinalis colli, complexus, trachelo-mastoid, and transversalis colli. The tendons of insertion of the splenius colli are interposed between the insertions of the levator anguli scapulae in front, and the transversalis colli beMnd. xhe splenii of opposite sides of the neck leave between them a trian- gular interval, in which the complexus is seen. Fourth Layer. Dissection.—The two serrati and two splenii muscles must be removed by cutting them away from their origins and insertions, to bring the fourth layer into view. Three of these muscles, viz. sacro-lumbalis, longissimus dorsi, and MUSCLES OF THE BACK. 203 spinalis dorsi, are associated under the name of erector spinae. They occupy the lumbar and dorsal portion of the back. The remaining four are situated in the cervical region. The Sacro-lumbalis and Longissimus Dorsi arise by a common origin from the posterior third of the crest of the ilium, from the posterior surface of the sacrum, and from the lumbar vertebrae; opposite the last rib a line of separation begins to be perceptible between the two muscles. The sacro-lumbalis is inserted by separate tendons into the angles of the six lower ribs. On turning the muscle a little out- wards, a number of tendinous slips will be seen taking their origin from the ribs, and terminating in a muscular fasciculus, by which the sacro- lumbalis is prolonged to the upper part of the thorax. This is the musculus accessorius ad sacro-lumbalem: it arises from the angles of the six lower ribs, and is inserted by separate ten- dons into the angles of the six upper ribs. The longissimus dorsi is inserted into all the ribs, between their tubercles and angles. The Spinalis Dorsi arises from the spinous processes of the two upper lumbar and three lower dorsal vertebrae, and is inserted into the spinous processes of all the upper dorsal verte- brae ; the two muscles form an ellipse, which appears to enclose the spinous processes of all the dorsal vertebrae. Relations. — The erector spinae muscle is in relation by its superficial surface (in the lumbar region) with the conjoined aponeurosis of the transversalis and internal oblique muscle, which separates it from the aponeurosis of the serratus posticus inferior, and longissimus dorsi; (in the dorsal region) with the vertebral aponeurosis, which separates it from the latissimus dorsi, trapezius, and serratus posticus superior, and with the splenius. By its deep surface (in the lumbar region) with the multifidus spinae, trans- verse processes of the lumbar vertebrae, and with the middle layer of the aponeurosis of the transversalis abdominis, which separates it from the quadratus lumborum; (in the dorsal region) with the multifidus spinae, semi-spinalis dorsi, levatores costarum, intercostal muscles, and ribs as far as their angles. Internally or mesially with the multifidus spinae, and semi-spinalis dorsi, which separate it from the spinous processes and arches of the vertebrae. The two layers of aponeurosis of the transversalis abdominis, together * The fourth and fifth, and part of the sixth layer of the muscles of the back. 1. The common origin of the erector spina? muscle. 2. The sacro-lumbalis. 3. The longissi- mus dorsi. 4. The spinalis dorsi. 5. The cervicalis ascendens. 6. The transvessalis colli. 7. The trachelo-mastoideus. 8. The complexus. 9. The transversalis colli, showing its origin. 10. The semi-spinalis dorsi. 11. The semi-spinalis colli. 12. The rectus posticus minor. 13. The rectus posticus major. 14. The obliquus superioi. 15. The obliquus inferior. 16. The multifidus spina?. 17. The levatores costarum IS. Intertransversales. 19. The quadratus lumborum. 204 MUSCLES OF THE BACK. with the spinal column in the lumbar region, and the vertebral aponeu- rosis with the ribs and spinal column in the dorsal region, form a com- plete osseo-aponeurotic sheath for the erector spinae. The Cervicalis Ascendens is the continuation of the sacro-lumbalis upwTards into the neck. It arises from the angles of the four upper ribs, and is inserted by slender tendons into the posterior tubercles of the trans- verse processes of the four lower cervical vertebrae. Relations.—By its superficial surface with the levator anguli scapulae; by its deep surface with the upper intercostal muscles and ribs, and with the intertransverse mu cles; externally with the scalenus posticus; and internally with the transversalis colli. The tendons of insertion are inter- posed between the attachments of the scalenus posticus and transversalis colli. The Transversalis Colli would appear to be the continuation up- wards into the neck of the longissimus dorsi; it arises from the transverse processes of the five upper dorsal vertebrae, and is inserted into the pos- terior tubercles of the transverse processes of the five middle cervical vertebrae. Relations. — By its superficial surface with the levator anguli scapulae, splenius and longissimus dorsi. By its deep surface with the complexus, trachelo-mastoideus and vertebrae ; externally with the musculus accesso- rius ad sacro-lumbalem, and cervicalis ascendens; internally with the trachelo-mastoideus and complexus. The tendons of insertion of this muscle are interposed between the tendons of insertion of the cervicalis ascendens on the outer side, and of origin of the trachelo-mastoid on the inner side. The Trachelo-mastoid is likewise a continuation upwrards from the longissimus dorsi. It is a very slender and delicate muscle, arising from the transverse processes of the four upper dorsal and four lower cervical vertebrae, and inserted into the mastoid process to the inner side of the digastric fossa. Relations.—The same as those of the preceding muscle, excepting that it is interposed between the transversalis colli and the complexus. Its tendons of attachment are the most posterior of those which are connected with the posterior tubercles of the transverse processes of the cervical ver- tebrae. The Complexus is a large muscle, and with the splenius forms the great bulk of the back of the neck. It crosses the direction of the splenius, arising from the transverse processes of the four upper dorsal, and from the transverse and articular processes of the four lower cervical vertebrae, and is inserted into the rough surface on the occipital bone between the two curved lines, near the occipital spine. A large fasciculus of the com- plexus is so distinct from the principal mass of the muscle as to have led to its description as a separate muscle under the name of biventer cervicis. This appellation is not inappropriate, for the muscle consists of a central tendon, with two fleshy bellies. The complexus is crossed in the upper part of the neck by a tendinous intersection. Relations. — By its superficial surface with the trapezius, splenius, tra- chelo-mastoid, transversalis colli, and longissimus dorsi. By its deep sur- face with the semi-spinalis dorsi and colli, the recti and obliqui. It is separated from its fellow of the opposite side by the ligamentum nuchae, and from the semi-spinalis colli by the profunda cervicis artery and prin- MUSCLES OF THE BACK. 205 reps cervicis branch of the occipital, and by the posterior cervical plexus of nerves. Fiflh Layer. Dissection.—The muscles of the preceding layer are to be removed by dividing them transversely through the middle, and turning one extremity upwards, the other downwards. In this way the whole of the muscles of the fourth layer may be got rid of, and the remaining muscles of the spine brought into a state to be examined. The Semi-spinales Muscles are connected with the transverse and spinous processes of the vertebrae, spanning one half of the vertebral column ; hence their name semi-spinales. The Semi-spinalis Dorsi arises from the transverse processes of the six lower dorsal vertebrae, and is inserted into the spinous processes of the four upper dorsal, and two lower cervical vertebrae. The Semi-spinalis Colli arises from the transverse processes of the four upper dorsal vertebrae, and is inserted into the spinous processes of the four upper cervical vertebrae, commencing with the axis. Relations.—By their superficial surface the semi-spinales are in relation from below upwards with the spinalis dorsi, longissimus dorsi, complexus, splenius, with the profunda cervicis and princeps cervicis artery, and pos- terior cervical plexus of nerves. By their deep surface with the multifidus spinoe muscle. Occipital Group.—This group of small muscles is intended for the varied movements of the cranium on the atlas, and the atlas on the axis. They are extremely pretty in appearance. The Rectus Posticus Major arises from the spinous process of the axis, and is inserted into the inferior curved line of the occipital bone. The Rectus Posticus Minor arises from the spinous tubercle of the atlas, and is inserted into the rough surface on the occipital bone, beneath the inferior curved line. The Rectus Lateralis is extended between the transverse process of the atlas and the occipital bone ; it arises from the transverse process of the atlas, and is inserted into the rough surface of the occipital bone, ex- ternal to the condyle. /The Obliquus Inferior arises from the spinous process of the axis, and passes obliquely outwards to be inserted into the extremity of the trans- verse process of the atlas. The Obliquus Superior arises from the extremity of the transverse pro- cess of the atlas, and passes obliquely inwards to be inserted into the rough surface of the occipital bone, between the curved lines. Relations.—By their superficial surface the recti and obliqui are in rela- tion with a strong aponeurosis which separates them from the complexus. By their deep surface with the atlas and axis, and their articulations. The rectus posticus major partly covers in the rectus minor. The rectus lateralis is in relation by its anterior surface with the internal jugular vein, and by its posterior surface with the vertebral artery. Sixth Layer. Dissection.—The semi-spinales muscles must both be removed to obtain a good view of the multifidus spinae which lies beneath them, and fills up the concavity between the spinous and transverse processes, the whole length of the vertebral column. 206 MUSCLES OF THE BACK. The Multifidus Spinae* consists of a great number of fleshy fascicul. extending between the transverse and spinous processes of the vertebrae, from the sacrum to the axis. Each fasciculus arises from a transverse pro- cess, and is inserted into the spinous process of the first or second vertebra above. Some deep fasciculi of the multifidus spinae have recently been described by Professor Theile under the name of rotatores spinae. Relations.—By its superficial surface with the longissimus dorsi, semi- spinalis dorsi, and semi-spinalis colli. By its deep surface with the arches and spinous processes of the vertebral column, and in the cervical region with the ligamentum nuchae. The Levatores Costarum, twelve in number on each side, arise from the transverse processes of the dorsal vertebrae, and pass obliquely out- wards and downwards to be inserted into the rough surface between the tubercle and angle of the rib below them. The first of these muscles arises from the transverse process of the last cervical vertebra, and the last from that of the eleventh dorsal. The levatores of the inferior ribs, besides the distribution here described, send a fasciculus downwards to the second rib below their origin, and consequently are inserted into two ribs. Relations.—By their superficial surface with the longissimus dorsi and sacro-lumbalis. By their deep surface with the intercostal muscles and ribs. The Supra-spinalis is a small and irregular muscle lying upon the spinous processes in the cervical region and composed of several fasciculi. The fasciculi arise from the inferior cervical and superior dorsal vertebrae, and are inserted into the spinous process of the axis. From its analogy to the spinalis dorsi this muscle has been named spinalis colli. It is sometimes wanting. The Interspinales are small muscular slips arranged in pairs and situ- ated between the spinous processes of the vertebrae. In the cervical re- gion there are six pairs of these muscles, the first being placed between the axis and third vertebra, and the sixth between the last cervical and first dorsal. In the dorsal region, rudiments of these muscles are occa- sionally met with between the upper and lower vertebrae, but are absent in the rest. In the lumbar region there are six pairs of interspinales, the first pair occupying the interspinous space between the last dorsal and first lumbar vertebra, and the last the space between the fifth lumbar and sacrum. They are thin and imperfectly developed. Rudimentary inter- spinales are occasionally met with between the lower part of the sacrum and the coccyx; these are the analogues of*the caudal muscles of brutes; in man they have been named collectively the extensor coccygis. ' The Intertransversales are small quadrilateral muscles situated be- tween the transverse processes of the vertebrae. In the cervical region they are arranged in pairs corresponding with the double conformation of the transverse processes, the vertebral artery and anterior division of the cervical nerves lying between them. The rectus anticus minor and rectus lateralis represent the intertransversales between the atlas and cranium. In the dorsal region the anterior intertransversales are represented by the intercostal muscles, while the posterior are mere tendinous bands, mus- cular only between the first and last vertebrae. In the lumbar region, the * Professor Theile of Berlin has examined this muscle very closely, and describes a portion of it under the name of Rotatores spixs, which seems to be an unnecessary complication.—G. MUSCLES OF THE BACK. 2C7 anterior intertransversales are thin, and occupy only part of the space be- tween the transverse processes. Analogues of posterior intertransversales exist in the form of small muscular fasciculi (interobliqui) extended be tween the rudimentary posterior transverse processes of the lumbar ver- tebrae. With regard to the origin and insertion of the muscles of the back, the student should be informed, that no regularity attends their attachments. At the best, a knowledge of their exact connexions, even were it possible to retain it, would be but a barren information, if not absolutely injurious, as tending to exclude more valuable learning. I have therefore endea- voured to arrange a plan, by which they may be more easily recollected, by placing them in a tabular form (p. 208), that the student may see, at a single glance, the origin and insertion of each, and compare the natural grouping and similarity of attachments of the various layers. In this manner also their actions will be better comprehended, and learnt with greater facility. .'frtions.—The upper fibres of the trapezius draw the shoulder upwards and backwards; the middle fibres, directly backwards; and the lower downwards and backwards. The lower fibres also act by producing ro- tation of the scapula upon the chest. If the shoulder be fixed the upper fibres will flex the spine towards the corresponding side. The latissimus dorsi is a muscle of the arm, drawing it backwards and downwards, and at the same time rotating it inwards; if the arm be fixed, the latissimus dorsi will draw the spine to that side, and, raising the lower ribs, be an inspiratory muscle ; and if both arms be fixed, the two muscles will draw the whole trunk forwards, as in climbing or walking on crutches. The levator anguli scapulae lifts the upper angle of the scapula, and with it the entire shoulder, and the rhomboidei carry the scapula and shoulder up- wards and backwards. In examining the following table, the student will observe the constant recurrence of the number four in the origin and insertion of the muscles. Sometimes the four occurs at the top or bottom of a region of the spine, and frequently includes a part of two regions, and takes two from each, as in the case of the serrati. Again, he will perceive that the muscles of the upper half of the table take their origin from spinous processes, and pass outwards to transverse, whereas the lower half arise mostly from transverse processes. To the student, then, we commit these reflections, and leave it to the peculiar tenor of his own mind to make such arrange- ments as will be best retained by his memory. The serrati are respiratory muscles acting in opposition to each other, the serratus posticus superior drawing the ribs upwards, and thereby ex- panding the chest; and the inferior drawing the lower ribs downwards and diminishing the cavity of the chest. The former is an inspiratory, the latter an expiratory muscle. The splenii muscles of one side draw the vertebral column backwards and to one side, and rotate the head to- wards the corresponding shoulder. The muscles of opposite sides, acting together, will draw the head directly backwards. They are the natural antagonists of the sterno-mastoid muscles. The sacro-lumbalis with its accessory muscle, the longissimus dorsi, and spinalis dorsi, are knowTn by the general term of erectores spince, which sufficiently expresses their action. They keep the spine supported in the vertical position by their broad origin from below, and by means of theii 20S TABLE OF ORIGIN AND INSERTION l~ Layers. 1st Layer, Trapezius . . . < Latissimus dorsi . < 2d Layer. ;uli sea-) Levator anguli sca- pulae Rhomboideus mi nor .... Rhomboideus major 3d Layer. Serratus posticus superior . . Serratus posticus inferior . . Splenius capitis Splenius colli .{ itis . S 1 • i 4th Layer. Sacro-lumbalis . . Accessorius ad sa-) cro-lumbalem . ) 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 .....3 Rectus lateralis Obliquus inferior . Obliquus superior . 6th Layer. Multifidus spinae . Levatores costarum Supra-spinales . . Inter-spinales . .< Inter-transversales Spinous Processes. ORIGIN. Transverse Pro- cesses. last cervical, 12 dorsal 6 lower dorsal, 5 lumbar lig. nuchae and last cervical 4 upper dorsal lig. nuchae, last cervical, 2 upper dorsal 2 lower dorsal, 2 upper lumbar lig. nuchae, last cervical, 6 upper dorsal 2 lower dorsal, 2 upper lumbar axis atlas cervical Cervical and lumbar 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 of 4 upper Additional. occipital bone and' ligamentum nuchae^ sacrum and ilium . sacrum and ilium . sacrum and lumbar ? vertebra . 3 OF THE MUSCLES OF THE BACK. 209 INSERTION. Spinous Processes. Transverse Processes. Ribs. 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 upper dorsal, ( 2 lower cervical. 14 upper cervical, ( except atlas. (from last lumbar to ( axis. cervical. cervical and lumbar. 4 lower cervical. 4 lower cervical. atlas. 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* o 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, draws the head backwards, and counteracts the muscles on the anterior part of the neck. It assists also in the rotation of the head. The semi-spinales and multifidus spinae 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 recti 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- rioily 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 interna] 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 of the 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 of the 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 of the abdominal muscles is to be commenced by making 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 ABDOMEM. 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 of the muscle at once. If the external oblique muscle be dissected on both sides, a white ten- dinous line will be seen along the middle of the 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 linece semilunares. Some transverse lines, linece transversce, three or four in number, connect the linese 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 betwTeen corresponding pro- cesses of the serratus magnus, and the three lower of the latissimus do^si. Soon after its origin it spreads out into a broad aponeurosis, which is in- serted into the outer lip of the crest of the ilium for one half its length, the anterior superior spinous process of the ilium, spine of the os pubis, pecti- neal line, front of the 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 of the aponeuro- sis of the 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. T'he 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 of the 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 alone Poupart's ligament and the crest of the ilium. Poupart's ligamen4 Fig. 116.* * The muscles of the anterior aspect of the trunk; on the left side the superficial .ayer i9 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 muscle. 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 linea? 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 inte*rcolumnar fibres are seen proceeding upwards from Poupart's ligament to strengthen the ring. The numbers 14 and 15 are situated upon the fascia lata of the 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 of the anterior segment of its sheath : * the posterior segment of its sheath with the divided edge of the anterior segment. 17 The pyramidalis muscle. IS. 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 vertebra;. 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 lamella;, 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 of the 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 lower border of the muscle, which ac- company the cord downwards 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 of the 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 externa) 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 A'ill 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 of the 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 libs, 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 of the 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 tho transversalis abdominis. 1. The costal origin of the latissimus dorsi muscle. 2. The serratus magnus. 3. The upper part of the external oblique muscle, divided in the di- rection best calculated to show the muscles beneath, without interfering with its indigi- tations with the serratus magnus. 4. Two of the 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. 9. The lower part of the left rectus, with the aponeurosis of the 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 vagina? 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 lower 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, twTo 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 of the 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 formalfon of its sheath. The sheath of the 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 wiien 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 crus. 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 cesophagus and pneu- mogastric nerves ; and a third, the aortic, which is formed by a tendinous 19 218 MUSCLES OF THE ABDOMEN. arch thrown from the tendon of one cms to that of the other, beneath which pass the aorta, the right vena azygos, and thoracic duct. The great splanchnic nerves pass through openings in the lesser muscle on each side, and the lesser splanchnic nerves through the fibres which arise from the ligamentum arcuatum inter- num. Relations.—By its superior surface with the pleurae, the pericardium, the heart, and the lungs. By its inferior surface with the peritoneum; on the left with the stomach and spleen ; on the right with 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 pyramid ales, 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 of the linea alba. The abdominal are expiratory muscles, and the chief agents of expulsion ; by their action the fcetus 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, wmch 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 or shorter tendon of the lesser muscle. 11. The aortic opening occupied by the aorta which is cut short off. 12. A portion of the 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 Iigamenium 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. Fig. 118.* 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- bial 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, Sphincter ani, Erector penis, Levator ani, Compressor urethrae, Coccygeus. 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 of the perineum. And as this is a dissection which demands some degiee 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, carry 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 of the ischium and of the pubes, to the opposite side of the scrotum, where 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 off 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 every other situation. The common superficial 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 URiNiE (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 of the 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 Ureth^e (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 lower 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 mimed between the prostate gland and rectum, the recto-vesical fascia. TRANSVERSUS PERINET. 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 Relutions.—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 urethrae, 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 of the perineum. 1. The acceleratores urinse 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 of the ischium (S) 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 coccygeuj muscle. The boundaries of the perineum are well seen in this engraving. + 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. Tha 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 urinse. 19* ooo MUSCLES OF THE PERINEUM. down the bladder from its attachment to the os pubis, and removed u plexus of veins and the posterior layer of the deep perineal fascia. The Sphincter Ani is a thin and elliptical plane of muscie closely ad- herent to the integument, and surrounding the opening of the anus. It arises posteriorly in the superficial fascia around the coccyx, and by a fibrous raphe from the apex of that bone ; and is inserted anteriorly into die 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 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 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 lower 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 vaginae 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- 'iae, and the levator ani into the side of the vagina. The other muscles are precisely similar in their attachments to those in ihe 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 draw 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 Cowper'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 Ihe 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 of the pelvis to bear a greatej 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. Lateral Thoracic Region. Serratus magnus. Anterior Scapular Region Subscapularis. 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 jppei 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 of the 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 whole 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 of the upper portion of the 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 trie 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 muscle outwards. 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- p 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 Subclavius muscle arises by a round tendon from the cartilage of the first rib, and is inserted into the under surface of the clavicle. This muscle is concealed by the costo-coracoid membrane, an extension of the deep cervical fascia, by which 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 wiiole 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 Ihe posterior border, and an inferior portion consisting of the last five serrations which in digitate 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 bj 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, wiiere 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 tiumerus. 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 supi a-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 of the 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 lower 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 integument. 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, scapula head of the triceps and integument. By its anterior surface, with th subscapularis, latissimus dorsi, coraco-brachialis, short head of the biceps axillary vessels, and branches of the 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, which 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; efdos, resemblance), which arises from the outer third of the clavicle, from the acromion process, and from the wiiole 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 view7 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 of the biceps, tendon of the pectoralis major, tendon of the 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 horder is thin and tendinous above, where it is connected with the apo- neurotic covering of the infra-spinatus muscle, and thick below. Actions. — The deltoid is the elevator muscle of the arm in a direct ANTERIOR HUMERAL REGION. 229 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 ilhiM ration of a lever of the third power, so common in the animal machine, by which velocity is gained ?t 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—xstpaXai, two heads) arises by two tendons, one the short head, from the coracoid process in common with the coraco-brachi- alis ; the other the long head, from the upper part of the glenoid cavity. The muscle is inserted by a rounded tendon, into the tubercle of the ra- dius. The long head, a long slender tendon, passes through the capsular ligament of the shoulder joint enclosed in a sheath of the synovial mem- brane ; after leaving the cavity of the joint, it is lodged in the deep groove that separates the two tuberosities of the humerus, the bicipital groove. A small synovial bursa is interposed between the tendon of insertion, and the tubercle of the radius. At the bend of the elbow, the tendon of the biceps gives off from its inner side a broad tendinous band, which protects the brachial artery, and is continuous with the fascia of the fore-arm. Relations.—By its anterior surface with the deltoid, pectoralis major, superficial and deep fascia and integument. By its posterior surface the • The muscles of the anterior aspect of the upper arm. 1. The coracoid process o'' the scapula. 2. The coraco-clavicular ligament (trapezoid), passing upwards to th" scapular end of the clavicle. 3. The coraco-acromial ligament, passing outwards to the acromion. 4. The subscapularis muscle. 5. The teres major; the triangular space above this muscle is that through which the dorsalis scapulae vessels pass. 6. The oraco-brachialis. 7. The biceps. S. The upper end of the radius. 9. The brachialis anticus; a portion of the muscle is seen on the outer side of the tendon of the biceps 1U. The internal head of the triceps. 20 230 POSTERIOR HUMERAL REGION. short head rests upon the subscapularis, from which it is separated by a bursa. In the rest of its extent the muscle is in relation with the humerus, the teres major, latissimus dorsi, and brachialis anticus ; from the latter it is separated by the external cutaneous nerve. By its inner border with the coraco-brachialis, brachial artery and veins, and median nerve ; the brachial vessels crossing its tendon at the bend of the elbow. By its outer border with the deltoid and supinator longus. The Brachialis Anticus is a broad muscle covering the whole of the anterior surface of the lower part of the humerus; it arises by twro fleshy serrations from the depressions on either side of the insertion of the del- toid, from the anterior surface of the humerus, and from the intermuscular septa attached to the condyloid ridges. Its fibres converge to be inserted into the coronoid process of the ulna. Relations.—By its anterior surface with the biceps, external cutaneous nerve, brachial artery and veins, and median nerve. By its posterior sur- face with the humerus, anterior ligament of the elbow joint, and inter- muscular aponeurosis. The latter separates it from the triceps. By its external border with the supinator longus, extensor carpi radialis longior, musculo-spiral nerve, and recurrent radial artery. By its internal border with the intermuscular aponeurosis, which separates it from the triceps and ulnar nerve, and with the pronator radii teres. Actions.—The coraco-brachialis draws the humerus inwards, and assists in flexing it upon the scapula. The biceps and brachialis anticus are flexors of the fore-arm, and the former a supinator. The brachialis anticus is a powerful protection to the elbow joint. Fig. 121.* Posterior Humeral Region. Triceps extensor cubiti. Dissection.—Remove the integument and fascia from the posterior aspect of the upper arm. The Triceps (ehind it. the tendon of the 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 the 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 of the ankle joint. Posterior Tibial Region. Superficial Group. Gastrocnemius, Plantaris, Soleus. Dissection.—Make an incision from the middle of the popliteal space, down tne middle of the posterior part of the leg to the heel, bounding it inferiorly by a transverse incision, passing between 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 (yatfcPoxvvjfjuov, the bellied part of the leg) arises. by two heads, from the two condyles of the femur, the inner head being PLANTARIS—SOLEUS. 255 me 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 jeing 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 VfflPf//;] 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 power (these muscles) at the other extremity. They are, therefore, the walking muscles, and perform all movements that require the support of the wrhole 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 posticm and flexor longus digitorum passing into the foot behind the inner ankle. 256 FLEXOR LONGUS DIGITORUM. 'I 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 strong 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.* S1de °f trie 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 of the knee joint and with the upper part of the 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 nasses 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 .he 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 of the 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 of the 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 muscle. 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, wiiich 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 of the tarsu* 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* k 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 (negivvi, fibula, extensor tarsi fibularis longioi) 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 of the 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 y> 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 lower 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, wiiich 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 uones; 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^rs^ dorsal interosseous is inserted into the inner side of the 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. 135.* Fig. 136-f 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 tertn. 4. Adductor quarti. | 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 brevi? bgitorum. 260 MUSCLES OF THE SOLE OF THE FOOT. 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 outei 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 of the 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 of the 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, wiiich 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 of the second layer of muscles of the sole of the foot. 1. The divided edge of the plantar fascia. 2. The musculus accessorius. 3. The tendon of the flexor longus digitorurr 4. The tendon of the flexor longus pollicis. 5. The flexor brevis pollicis. f. The adductor pollicis. 7. The flexor brevis minimi digiti. 8. 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 Fig. 138* Dissection. — The three preceding muscles must be divided from their origin, and anteriorly through their tendons, and removed, in order to hring 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 of the extensor tendons, and into the base of the first phalanx of the four lesser toes. Relations. — By their superficial surface, with the tendons of the flexor brevis digitorum. By tiieir 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 of the 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 of the tendon of the 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 of the foot. 1. Tendon of the flexor longus pollici.s 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. fourtn 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 from the base of the 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 of the 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. , • { one dorsal, Interossei, three dorsal, 15 I three plantar. Abductor minimi digiti. THE FASCIAE. 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 FASCIiE. Fascia (fascia, a bandage) is the name assigned to laminae of various extent and thickness, which are distributed through the different regions of the 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 ; while it forms at the same time a yield- ing tissue, through which the minute vessels and nerves pass to the papil- lary layer of the 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 c\u • Plant ir interossei. 1. Abductor tertii. 2. Abductor quarti. 3. Interosseous minimi duuii. 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 lowTer, 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 vaginae 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 of the 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. FASCIA 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 wiiich invests the muscles of the neck, and retains and supports the vessels and nerves. It commences posteriorly at the ligamentum nuchae, 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 FASCLE 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 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 cf the sterno-mastoid muscle, the deep fascia is attached to the border of the 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 of the 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 br- 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 of the deep cervical fascia of opposite sides of the neck. 8. Section of the 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 scapulfE. 22. Complexus. 23. Trachelo-mastoid. 24. Trans- versalis colli. 25. Cervicalis ascendens. 26. The semi-spinalis colli. 27. The multi- fidus spina3. 28. 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 ^n v' e " Anatoinv of the Thymus Gland." 23 266 ABDOMINAL FASCIAE. ascending layer is attached to the trachea, and becomes continuous with the sheath of the carotid vessels, and with the deep cervical fascia; the 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 filjrou^ 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 of the 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 of the latter cavity is reflected inwards to the sides of the bladder. This fascia is continuous throughout the wiiole 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 ihe 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 Jie 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 oorder 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. ___________________________ Behina. Aponeurosis of exter- c . , r iii- Spermatic canal. nal oblique. r Below. Grooved border of Poupart"s ligament. Transversalis fascia. Conjoined tendon of internal oblique and transversalis. 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 fcetus. 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 liernia (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 vertebrae, 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 two 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 FASCLE. 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. Tig. 141.« The obturator fascia passes directly downwards from the splitting of the layers of the 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 below 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 downwards 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 die 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. Tne 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 FASCIAE. 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 of the 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 duplicature in its proper situa- tion. *The pubic arch with the attachments of the perineal fascia;. 1, 1, 1. The superfl 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 of the deep perineal fascia, corresponding with the position of Cowper's glands. t A side view of the viscera of the pelvis, showing the distribution of the perineal and pelvic fascia?. 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 ti e 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 distmct layer of fascia, covering in a considerable plexus of veins. FASCIJE 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 of the 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 of the 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, which spread out over the sides of the hand, and are continuous with the dorsal fascia. The central portion is strong and tendinous: it is narrow at the wrist, where it is attached to the annular ligament, and broad over the heads of the 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 of the bladder, formed by the reflection of the pelvic fascia, from the internal surface of the os pubis to the neck of the bladder. 13. The edge of the 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 of the scrotum (18). 19. The layer of the 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. Ihe attachment of this fascia to the recto-vesical fold of peritoneum is seen at 2'2. 272 FASCIAE OF THE LOWER EXTREMITY. fascia is strengthened at its point of division into slips, by slrong 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. FASCIJE 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, wiiich 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 saphenous 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 of the femoral vessels, and the lower 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 outwards 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 Fis-144* 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 of the 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 of the 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,! 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 of the 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 liga- ment. 2, 2. The iliac portion of the fascia lata, attached along the margin of the crest 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 (G) and iliacus (7) ; the other (8) is lost upon the capsule of the hip joint (9). 10. The crural nerve, 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 femoial ar tery; the two vessels and the ring are surrounded by the femoral sheath, and thir, septa are sent between the anterior and posterior wall of the sheath, dividing the arCery from the vein, and the vein from the femoral ring. f This areolar tissue is sometimes very considerably thickened by a deposit of fa within its areolae, and forms a thick stratum over the hernial sac. 274 FASCLE 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 bursae. 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 of1 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 down 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 cf 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 AKTERIES. 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 (a^ t^sTv, 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 would 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 cceliac axis. In the division of an artery into two branches, it is observed that th combined areae of the two branches are somewhat greater than that of th single trunk; and if the combined areae 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 distributing 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 of the 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, tfrofxa mouth). This increase in the frequency of anastomosis in the smaller branches is a provision for counteracting the greater liability to impediment existing in them than in the larger branches. Where free- dom of circulation is of vital importance, this communication of the arteries is very remarkable, as in the circle of Willis in the cranium, or in the dis- tribution of the arteries of the heart. It is also strikingly seen in situations where obstruction is most likely to occur, as in the distribution to the ali- mentary canal, around joints, or in the hand and foot. Upon this free communication existing everywhere between arterial branches is founded the principle of cure in the ligature of large arteries; the ramifications of the branches given off from the artery above the ligature inosculate with those which proceed from the trunk of the vessel below the ligature; these anastomosing branches enlarge and constitute a collateral circulation, in which, as is shown in the beautifiul preparations made by Sir Astley Cooper, several large branches perform the office of the single obliterated trunk.* The arteries do not terminate directly in veins; but in an intermediate system of vessels, which, from their minute size (about 3^00" °f an incn m diameter), are termed capillaries (capillus, a hair). The capillaries con- stitute a microscopic network, which is distributed through every part of the body, so as to render it impossible to introduce the smallest needle point beneath the skin without wounding several of these fine vessels. It is through the medium of the capillaries, that all the phenomena of nutri- tion and secretion are performed. They are remarkable for their unifor- mity of diameter, 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 Ihe abdominal aorta; the animal died from over-feeding nearly two years after the operation STRUCTURE OF ARTERIES. 277 inoscvdate 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 ongitudinal 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 of the nerves is at present unknown. In the consideration of the arteries, we shall first describe the aorta, and * The second or middle coat of the 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 evidenties of belonging lo the muscular system of organic life ; so that the coat may, I think, be fairly staled to be a mixed one, composed of yellow, elastic, and organic muscular fibres. ' It is best studied in tl e 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 pul- monary artery as the efferent trunk of the pulmonary circulation. Fig. 145.» The aorta arises from the left ventricle, at the middle of the root of the 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 ascendingaorta. 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 oft" 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 of the corresponding lungs, and the relative posi- tion of these vessels is preserved. 20. Bronchial arteries. 21, 21. Intercostal arteries; •die 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. s Right pulmonary artery, Right pulmonary veins. Arch.—The upper border of the arch of the aorta is parallel with tho upper border of the second sterno-costal articulation of the right side in 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 of the Relations of the Arch of the Aorta. Move. 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 of the Relations of the Thoracic Aorta. In Front. ffisophagus, 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 of the Relations of the 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 semilunai gan- glion, Sympathetic ne- ve ARTERIA INNOMINATA. 281 Branches.—The branches of the aorta, arranged into a tabular form, are, Ascending aorta Arch of the aorta Thoracic aorta Abdominal aorta Coronary. ... • ( Right carotid, Arteria innominata, < r>b, , u i • T c. ,. , ' / Right subclavian. Left carotid, *• b 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 oi 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 of the left ventricle 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 thymus 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. 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 (xoc^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 neai 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. Left Side. Left carotid. 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. Interna, 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. Arteria innominata, Pleura. Thoracic duct. OUsophagus. EXTERNAL CAROTID ARTERY. The External carotid artery ascends nearly perpendicularly from oppo- site the upper borcer of the thyroid cartilage, to the space between the neck of the 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. 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. Posterior. 1. Superior thyroid, 4. Mastoid, 2. Lingual, 5. Occipital, 3. Facial. 6. Posterior auricular. Superior. 7. Ascending pharyngeal, 8. Parotidean, 9. Transverse facial. 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 downwrards to the thyroid gland to which 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 cc pital. 10. The posterior auricutai. 11. The transverse facial artery. 12. The internal maxillary 13. The 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 of the 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-fhyroi- dean membrane along the lower border of the thyroid cartilage. It sends branches through the membrane, to supply the mucous lining of the 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 snippino- the fraenum in children. 3. Facial artery. — The Facial artery arises a little above the great cornu of the 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 qngular 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, Superiof 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 of the body of the lower jaw, and anastomoses with branches of the 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 of the lower lip. The Inferior coronary runs along the edge of the lower 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 lip 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 of the 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 svmmetrical 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 of the 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 aquaeductus Fallopii and tympanum. 7. The Ascending pharyngeal artery, the smallest of the branches of the external carotid, arises from that trunk near its bifurcation, and as- cends between the internal carotid and the side of the 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 of the 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.—Orb itar, 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 of the 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 ; wre 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, ajid 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, Fig. H7.» 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 portion lies between the two heads of the external pterygoid muscle, and, in the spheno-maxillary fossa, is in relation with Meckel's ganglion. Maxillary Portion. Tympanic, Inferior dental, Arteria meningea media, Arteria meningea parva. Branches. 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 jawr in company with the dental nerve. Opposite the bicuspid teeth it divides into two 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 ; tno limits are bounded by the arrows. 6. The third or pterygo-maxillary portion. The branches of the 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 of the artery makes as it turns inwards to enter the pterygo-.naxillary fossa. 25 i 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 jaw, 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 of the 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 die 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 jaw, 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 wrould 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 jaw, 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 witn 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 small 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 wiiich 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, wiiich 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 ryajor. The Petrous portion is separated from the bony wall of the carotin canal by a lining of dura mater; it is in relation with the carotid plexus, and is covered in by the Casserian ganglion. ' * Fo* the boundaries of this space see page 188. 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 i 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. It 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 anil 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 die cheek, and anastomose with the transverse facial. OPHTHALMIC ARTERY. 293 The Supra-orbital artery follows the course of the frontal nerve, resting on the levator palpebrae 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, while the other, the dorsalis nasi, runs along the ridge of the 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 between 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 retinae 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 of the 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, sometimea 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.—Theirs/ portion, on the right side, is in relation, in 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 SLBCLAVIAN ARTERY—RELATIONS. 295 Plan of the Relations of the First Portion of the 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. Oesophagus. 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. Move. In Front. Subclavian vein, Subclavius. Supra-scapular artery, Platysma myoides. Subclavian artery, Third portion. Below. First rib. Behind. Brachial plexus, Scalenus posticus 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, j 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 lower 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 mammarj arteiy. 14. The superior intercostal. ■\ Edinburgh Medical and Surgical Journal, 1839. BASILAR artery 297 Lateral spinal, Posterior meningeal, Vertebral, \ 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 two 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 die 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 of the 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 die 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 of the diaphragm, and enters the sheath of the 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 of the 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 of the 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 side 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, First serration of serra- Tendon of sub- scapularis, Pectoralis major, Pectoralis minor, Pectoralis major. tus magnus, Plexus of nerves. Coraco-brachialis. Branches.—The branches of the Axillary artery are seven in number:—• Fig. 150." Thoracica acromialis, 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 .he deep fascia of the fore-arm. It is this process which separates the median basilic vein from the brachial artery. 4. The outer border of the 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 lowTer 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 scapula:, 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 two 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 wiiich 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. Tha 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. TI13 anterior circumflex is observed, between the two heads of the biceps, crossing the aeck 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 wiiich 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. Outer Side. Brachial artery. Coraco-brachialis, Biceps. Behind. Short head of triceps, Coraco-brachial is, Brachialis anticus, Tendon of biceps. The brandies 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 which 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 of the 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. l.The lower part of the biceps muscle. 2. The inner condyle of the humerus with the humeral origin of the pronator radii teres and flexoi 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 volse. 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 nor interosseous, as it is passing through fhe 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 of the hand, forming the deep palmar arch, and terminates by inoscu lating widi 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 wTrist 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, ( Muscular. ' 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 of the superioi profunda. This vessel gives off numerous muscular branches. The Muscular branches are distributed to the muscles on the radial side of the 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; wiien of large size it supplies the palmar side of the thumb and the radial side of the 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 of the 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 two small branches which run along the sides of the dorsal aspect of the thumb. The Princeps pollicis descends along the border of the 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 Interossece, 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, being 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 nervp for the lower two-thirds of its extent. Plan of the Relations of the 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 of the flexor sublimis digitorum, The Branches of the ulnar artery may be arranged, like those of the radial, into three groups:— Anterior ulnar recurrent, Posterior ulnar recurrent, Fore-arm, ^ Interosseous< S A^erior interosseous, Posterior interosseous. Wrist, Hand, Muscular. Carpalis anterior, Carpalis posterior. Digitales. The Anterior ulnar recurrent arises immediately below the elbow, and ascends in front of the joint between the pronator radii teres and brachialis anticus, wiiere 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 backwards beneath the origins of the 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 Detween 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, which 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 wrrist 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, wiiich 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 minimi digiti near their origins, and terminates by inosculating with the superfi- cialis volae upon the ball of the 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 parsing 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 off 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 vertebrae, 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, C 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, which 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 cceliao 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 Fig. 152* j^h jn length, and divides into three large branches, gastric, he- patic, and splenic. Relations. — The trunk of the cceliac 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 of the three branches of the cceliac axis, ascends between the two layers of the 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 lowrer 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 which 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 of the 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. 1'he femoral artery. ■j- 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, „ i j v ^ Gastro-epiploica dextra, Gastro-duodenahs, j PancreatJco-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 cceliac 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 Pancreaticce parvce are numerous small branches distributed to the pancreas, as the splenic border runs along its 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, betwten the layers of the gastro-splenic omentum, to the great end of the stomach, to which they are distributed, inosculating with branches of the 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 twenty in number, and are dis- * The distribution of the branches of the 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 of the duodenum. 9. The pancreas. 10. The spleen. 11. The aorta. 12. The coeliac 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 of the 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 portioCi »f 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 which 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 of the supe- rior mesenteric artery, which inosculates with the pancreatico-duodenalis. 14. The co hca dextra. 15. The ileo-colica. 16, 16. The branches from the convexity of the supe- rior mesenteric to the small intestines. 27 314 SPERMATIC ARTERIES. The Colica dextra arises from about the middle of the concavity of the superior mesenteric, and divides 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 which arise from the front of the aorta below 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 uV 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 caecum and appendix* cseci. 3. The ascending colon. 4. The transverse 'jolon 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 of the superior mesenteric artery. 12,12 Sigmoid branches. 13. The superior haemorrhoidal artery. 14. The pancreas. 15. The descending portion of the 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 ot 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 two 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 of the 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 Rexal 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 which passes backwards between the transverse pro- cesses, and is distributed to the vertebrae and spinal cord and to the mus ^les 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 Branches of the 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 cceliac 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 two 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 diac 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- nor 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, Middle vesical, Middle haemorrhoidal, Ami in the female the— Uterine, And of the posterior trunk, the— Ilio-lumbar, Obturator, Ischiatic, Internal pudic. Vaginal. Lateral sacral, 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 of the bladder. The cord may ♦The distribution and branches of the 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 trunk. 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 of the 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 lacro-ischiatic foramen. 20. The sacra media. 21. The right common iliac artery cut ihort. 22. The femoral ai'ery. 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 of the body of the 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 of the 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 irunk 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 of the ischium, and re-enters the pelvis through the lesser sacro-ischiatic foramen; it then crosses the internal obturator muscle to the ramus of the 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 of the 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. 319 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 of the 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 forward 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 of the perineum; on the right side the superficial arteries are seen, and on (ho 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 urinaa muscles, enclosing the bulbous portion of the 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 of the ischium. 7. The lesser sacro-ischiatic ligament, attached by its small extremity to the spine of the ischium. 8. The coccyx. 9. The internal pudic artery, crossing the spine of the ischium, and entering the perineum. 10. External haemorrhoidal 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 of the 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 doisalis penis, ascends upon the dorsum of the crgan. 320 OBTURATOR ARTERY. resting on the transversus perinei muscle, and is named the transversalis 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 between 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 of the venous structure of the 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 lattei 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 twro 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 of the 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 and 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 of the 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 of the 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 aptery 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 wrorthy 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 which 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 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 of the 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 external 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. The 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 of the ilium. 2. The superficial epigastric artery. 16. The two external pudic arteries, superficial and deep. 17. The profunda artery, giving off 18, its external circumflei branch; and lower down the three perforantes. A small bend of the internal circum flex artery (8) is seen behind the inner margin of the femoral, just below the de»p ex tornal pudic artery. 19. The anastomotica magna, descending to the knee, upon which it ramifies (0). 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 down 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. 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- Inner Side. Femoral vein, Pectineus, Adductor longus, Sartorius. 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. Branches.—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 326 POPLITEAL ARTERY. divisions of the crural nerve, then between the rectus and aureus 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 of the 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 of the adductor magnus, where it anastomoses with the ischiatic, external circumflex, and superior perforating artery. It supplies the muscles of the upper and inner side of the 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 of the 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 of the anterior aspect of the 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- dtilar artery. The Anastomotica magna arises from the femoral wmile 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 of the 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. Outer Side. Biceps, External condyle, Gastrocnemius, Plantaris, Soleus. 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, Avith 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 femui. 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 die two external lateral ligaments of the joint, and the in 328 ANTERIOR TIBIAL ARTERY. 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, wiiich 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 downwards 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 between the tibialis anticus and extensor longus digitorum, lower down between the tibialis 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 vena 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 ei tensor 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 ey 'disor muscle. 2. The insertion of the ligamentum patellae into the lower border of the ,-atelIa. 3. The tibia. 4. The extensor proprius pollicis muscle. 5. The extensor Ion. 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 tlie 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. Tendon 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. 14. The tarsea and metatarsea arteries; the tarsea is nearest the Hiikle, the metatarsea is seen giving off the interossece. 15. The dorsalis hallucis artery. 16. The communicating branch. 28* 330 POSTERIOR TIBIAL ARTERY. Fig. 160.» Branches.—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, Ihe peroneal arteries, and the external plantar. 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 forward 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 of the 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. W4 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 t bialis posticus. 6. The fibula; immediately below the figure is the origin of the flexor iongus 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 |) illicis 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 of the 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 of the 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. Inner Side. Vein. Posterior Tibial Artery. Outer Side. Posterior tibial nerve, Vein. Deeply. Tibialis posticus, Flexor longus digitorum, Tibia. Branches.—The branches of the posterior tibial artery are the- Peroneal, Nutritious, Muscular, Internal calcanean, Internal plantar, 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 ongus* pollicis, having the fibula to its outer side. Plan of the Relations of tlve Peroneal Artery, In Front. Soleus, Intermuscular fascia, Flexor longus pollicis. Peroneal Artery. Behind. Tibialis posticus. Outer Side. Fibula. 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 lowei 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 arteryproceeds 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 outwards 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 of the os calcis; to which the origins of the first layei 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 of the three external toes, and the outer side of the 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 wiiich 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 lowrer 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 of the peroneus longus. 5. The termination of the 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 ir>*«r 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 we 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. Relations.—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 side is the appendix of the corresponding auricle with a coronary artery; and above, the cardiac ganglion and the remains of the ductus arteriosus. The Right pulmonary artery passes beneath the arch and behind the ascending 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; while 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 wiiich 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 when 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 Dlood, 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 body, and generally in relation with the arteries ; in the limbs they are enclosed in the same sheath with those vessels, and they return the venous blood from the capillaries of the deep tissues. In company with all the smaller, and also with the secondary arteries, as the brachial, radial, and ulnar in the upper, and the tibial and peroneal in the lower extremity, there are two veins, placed one on each side of the artery, and named vene 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 \\je\\ 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 their 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 hypertrophicd. 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 two 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, venas 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 of the 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 of the head and neck may be arranged into three groups, viz. 1. Veins of the exterior of the 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 of the opposite side by a communicating trunk which constitutes the nasal zrch. 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 of the 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 of the masseter muscle, crossing the body of the 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 wiiich 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 of the 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, which collects the blood from the temporal muscle, and around the outer segment of the 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 of the 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 lower 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 of the head, follows the direction of the occipital artery, and passing deeply beneath the muscles of the back part of the 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 thy 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 of the 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 die 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 Vene 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 extremity of the sagittal suture Fig. i62.« the parietal veins, from the peri- cranium and scalp. Examined in its interior, it presents numer- ous transverse fibrous bands (tra- beculce), 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 vense 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 of the 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 of the 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 vena? 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. f Torcular (a press), from a supposition entertained by the older anatomists that tho columns of blood, coming in different directions, compressed each other at this poin; 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 inteinal carotid artery, accompanied by several filaments of the carotid plexus, and crossed by the sixth nerve; and, in its external wall, 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 of the tentorium, on the upper margin of the 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 of the base of the 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. I . 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 wiiich return the blood from the head are the— External jugular, Anterior jugular, Internal jugular, Vertebral. The External jugular vein is formed by the union of the 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 of the 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 of 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 vene 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— Fig. 164.* 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 (/3a e^0S, 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, wiiich 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 poi^t 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 downwards, 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 die fissure of Syl- vius, after having curved around the crus cerebri. The middle cornu should now be laid open, by inserting the little fingei 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 stir- See the note appended t6 the deainption of the choroid coat of the eye-ball 376 FASCIA DENTATA. face of the thalamus opticus, upon which are the two projections calleq 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 die— 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 of the 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 of the 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 luddum. This septum is thin and semi-transparent, and consists of two laminae 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 twc layers is a narrow space, the fifth ventricle, which is lined by a prrper 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 tremit) , 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, wiiich 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 of the 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- Fig- 171.* face, he will perceive the lyra above described. Beneath the fornix is the velum interporitum, 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 incisior. 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 of the cerebellum, showing the arbor vitce. 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 of the crura of the fornix descending to 7, one of the corpora albicantia. S. The septum lucidum. 9. The velum interpositum, communicating with the pia mater of the convolutions through the fissure of Bichat. 10. Section of the middle commissure situated 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 crus of the fornix (6) is situated. The interspace between 10 and 12 is tha 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 geniculatum externum is the larger of the two, and of a greyish colour; it is the principal origin of the 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 compiled of white fibres mixed with grey substance. They are essentially the inferior ganglia cf the 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 fioor is formed by the grey substance of the anterior termi- nation of the corpus callosum, called lamina cinerea, the tuber einereum, 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 wiiich Monro has given his name (foramen of Monro). It is the medium of communication between foramen commune posterius. 13. 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 einereum, 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 rounded ^lb. 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 of the 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 ca-llosum. 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 of the pineal gland are attached to the thalami optici, and may be traced along the upper and inner margin of those bodies to the crura of the 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 of the 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 wiiich, Bnd 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 diick 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 two are placed in the middle line, the nodulus and uvula, the for- mer being before the latter; the remaining two are named amygdale, 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 white 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 fioor 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 (linea trans- verse) the origin of the auditory nerves. And upon the lower part of the 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 veK.ricle, 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 " Neurog-aphia Universalis" was published at Lyons, in 16S5. CEREBELLUM. 381 gether with a layer of pia mater which forms its inferior boundary. In diis 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 of the 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, indsura 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 tondl, 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 of the 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- cuius 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 vite 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 somewhat nearer the commissure than to the lateral border of the 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 rest 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 of the brain : for this ourpose the organ should be turned upon its incised surface; and if die 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 tte 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 einereum, 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 dnerea. The lamina cinerea is the anterior part of the inferior boundary of the third ventricle. On each side of the 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 of the 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, which 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 crus cerebri and middle lobe would enter the middle cornu of the lateral ventricle. The Optic commissure is situated on the middle line; it is the point of communication between the two optic nerves. The Tuber dnereum is an eminence of grey substance situated immedi- ately behind the optic commissure, and in front of the corpora mammii- laria. From its centre there projects a small conical body of grey sub- stance, apparently a prolongation of the tuber einereum, the infundibulum. Ihe infundibulum is hollow in its interior, enclosing a short caecal canal 384 BASE OF THE BRAIN. 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 einereum 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 pituitar) 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 einereum, and between the crura cerebri. They are a part of the crura of the fornix, which, after their origin from the thalami optici, descend to the base of the brain, and making a sudden curve upon them- a 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 wiiitish-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 which 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 of the aqueduct of • The under surface or base of the brain. 1. The anterior lobe of one hemisphere of the cerebrum. 2. The middle lobe. 3. The posterior lobe almost concealed by (<1) 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. h. The olfactory nerves, with their bulbous expansions. 9. The substantia perforata at ihe inner termination of the fissure of Sylvius; the three roots of the olfactory nerve are seen upon the substantia perforata. The commencement of the transverse fissure on each side is concealed by the inner border of the middle lobe. 10. The commissure of 'he 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. Tha MEDULLA OBLONGATA. 385 Sylvius. In their interior they contain grey matter, wiiich has a semilunar shape when the crus is divided transversely, and has been termed the locm 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 a bridge across the upper part of the medulla oblongata ; and, contracting on each side into a thick rounded cord, enters the substance of the 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 of the cerebellum, and associates the two 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 of the 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, taperin^r sligKjJJy from above downwards, and situated one on either side of the nsfiira ion- 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 die corpora pyramidalia, about half an inch in length, and tuber einereum, 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. Tho 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 of the auditory and facial. 19. The corpora pyramidalia of the medulla oblongata; the corpus olivare and part of the corpus restiforme are seen at each side. Just below the numeral is the decussation of the fibres of the 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 Gail and Spurzheim. The work con taming his mode of dissection, " De Resolutione Corporis Humani," was published afte« Lis death, in 1591. 33 z 386 DIVERGING FIBRES. somewhat 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 silique, 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 of the 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 fourtn 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 of the 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. WThile 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 die 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 fibres,,and they are distinguished I 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 ^ arolii. 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 crus cerebri and cerebelli are the same as in the preceding figure. 6. The olfactory nerve. 7. The corpora albicantia. On the right side a portion of the brain has been removed to show the distribution of the diverging fibres. 8. The fibres of the corpus pyramidale passing through the substance of the pons Varolii. 9. The 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 of the 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 vitas is also seen. 15. The opposite hemisphere of the cere- Dellum r 388 CONVERGING FIBRES. The fibres which enclose the corpus olivare, under the name of fascicud siliquse, are separated by that body into two bands; the innermost of the two bands, funiculus silique internus, accompanies the fibres of the corpus pyramidale into the crus cerebri. The funiculus silique externus unites with a fasciculus proceeding from the nucleus olivae, 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 well as from the posterior columns of the 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, twro large bundles of fibres, the fasdculi 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 wiiich 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, wiiich 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 beniispheres. The Septum luddum 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. 1'he 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 larainoe 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 o the posterior common ligament, and below, by means of its pointed extremity, to the. coccyx. In the rest of its extent it is comparatively free, being connected, by a very loose areolar tissue only, to the walls of die spinal 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 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 which 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 lowTer enlargement is situated near 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, wiiich 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 two 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, wiiere 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 anterolateral 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 narrow 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 cervigal. 6. Opposite the 4th cervical. 7 Opposite the 3d cervical. 8. Section of medulla oblongata through the corpora oli vana. r 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 lamina; 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. -,, ( 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 rlentatum 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-Iateral columns of the 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 •jord. OLFACTORY NERVE. 393 ( Glosso-pharyngeal, 8th. < 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: {1st. Olfactory. 2d. Optic. 7th. Auditory. Motion Compound 3d. Motores oculorum. 4th. Pathetici. 6th. Abducentes. j 7th. Facial. [ 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. 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 in 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 swells at its extremity, * A view of the 1st pair or olfactory, with the nasal branches of the 5th. 1. Frontal sinus. 2. Sphenoidal sinus. 3. Hard palate. 4. Bulb of the olfactory nerve. 5. Branches of the 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 of the 5th. 8. Branches of 7, to Schneiderian membrane. 9. Ganglion of Cloquet in the foramen inci- tivum. 10. Anastomosis on the inferior turbinated bone of the branches of the 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 gemculata 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 einereum to form the ovtic commissure (chiasma). The tractus opticus is united with the crus cerebri and tuber einereum, and is covered in by the pia mater; the commissure is also connected with the tuber einereum, from which 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, wiiich 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. + 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 nervv, and is lost in the sclerotic coat of the 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 die eyeball, the retina. Near the globe, the nerve is pierced by a small artery, the arteria centralis retina?, 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 of the corpus callosum in front, by the substantia perforata on each side, and by the tuber einereum behind. Within the commissure die 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. Motor es Oculorum.—The motor oculi, a nerve of mo- derate size, arises from the inner side of the 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 palpebra?. 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 of the crus cerebri,* into the motor tract,f and as far as the superior fibres of the crus cerebri.:}: In 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 of the 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 of the 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 of the fibres of the superior peduncle of the 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 of the 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. f Sollv- * 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 palpebral 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 of the 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 of the 3d, 4th, and 6th pairs of nerves. 1. Ball of the 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 of the eye except the supe- rior oblique and external rectus. 4. The 4th pair or patheticus going to the superior oblique muscle. 5. One of the branches of the 5th. 6. The 6th pair or 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. fi have adopted the origin of this nerve, given by Dr. Alcock, of Dublin, as the result of his dissections, in the Cyclopaedia of Anatomy and Physiology. Mr. Mayo also traces the an'.erior 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 of the 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 Hgh more. 3 Tongue. A. Lower maxilla. 5. Root of 5th pair forming the ganglion of Lasser. 6. l»t branch, Ophthalmic. 7. 2d branch, Superior maxillary. 8. 3d branch, 34 398 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 wiiich 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 j. ,., , , ( Middle dental, Infra-orbital canal, { A , . i . i J ( Anterior dental. ^ .7 /• ^ Muscular, On the face, < n , ' J ' ( Cutaneous. The Orbital branch (n. subcutaneus malse) enters the orbit through the spheno-maxillary fissure, and divides into two branches, temporal and malar; the temporal branch ascends along the outer wall of the 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. I0/. Terminating branches of infra-orbital, called labial and palpebral. 20. Subcutaneus malse 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- oani. 24. Inferior dental nerve terminating in, 25. Mental branches. 26. Superficial oinporal 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 of the 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 oibicularis palpebrarum muscle. It communicates with branches of the infra-orbital and facial nerves. The Two branches from Meckel's ganglion ascend from diat body to join the nerve, as it crosses the spheno-maxdlary 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 distmct canals in the walls of the bone. Previously to their distribution, the dental nerves form a plexus (superior maxdlary 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 of the teeth, the gums, the mucous membrane of die floor of the 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 of the 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. Entering at the foramen ovale the nerve divides into two trunks, external and internal, wiiich 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 between 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, wiiere 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, while between the two pterygoid muscles, receives a branch from the inferior dental; lowrer 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 of the 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 of the chin and lower lip, and to the mucous membrane of the 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 backwards behind the articulation of the lower jaw, against wiiich 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 twu considerable branches of communication to the facial nerve, and then ascend* 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 malae 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 twro nerves which lie side by side on the posterior border of the crus cerebelli. The smaller and 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 fhe facial. Facial Nerve (portio dura). — The facial nerve arises from the ipper 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 right side. 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 4*h pair. 11. The 3d pair. 34* 2 a 402 FACIAL NERVE. crus cerebelli, and comes into relation with the auditory nerve, with whicK 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 canai 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 of the 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-fadal. 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 two 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. an • , ,. (Posterior auricular, After emerging at the \ „ . , .. ' stylo-mastoid foramen, j -p/ " 7 ' 3 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 Uie submaxillary gland, where it unites with the submaxillary ganglion The Posterior auricular nerve ascends behind the ear, between the AUDITORY NERVE. 403 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 Fig 182« 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-fadal gives off a number of branches, which 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 malae, 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 Cervicofacial 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 wTall or floor of the fourth ventricle, and winds 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 of the cervical plexus. 1. The facial nerve, escaping from the stylo-mastoid foramen, and crossing the ramus of the Jnver 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-mastoH 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. Cervioo-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 of the trapezius muscle. 1G. 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 of the 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 twro 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 of the 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 of the 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 communicate with each other, with the other divisions of the eighth pair, and with the trunk of the pneumogastric below 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 diat 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 between 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- haryngeal, may be traced through the fasciculi of the corpus restiforme nto 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. Fig. 183* Cardiac, Inferior or recurrent laryngeal, Pulmonary anterior, Pulmonary posterior, Oesophageal, Gastric. The Branches of communication form part of the complicated plexus at the base of the skull. The branches to the ganglion of Andersch are giveu 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 of the aqueductus Fallopii and joins the fa- cial nerve. In the aqueductus Fallopii the auri- cular nerve gives off two small filaments, one of XM 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 nsimed 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 superioi laryngeal artery, and is distributed to the mucous membrane of the 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 of the glosso-pharyn- geal nerve. 7. The ganglion of Andersch. 8. The trunk of the nerve. 9. The spinal accessory nerve. 10. The ganglion of the 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 of the inferior cornu of the 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 oesophao-us 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 of the oesophagus, and accompa- nies it to the cardiac orifice of the stomach. The Gastric branches are the terminal filaments of the two pneumoo-as- tric nerves; they are spread out upon the anterior and posterior surfaces of the 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. glion. 12. Its trunk. 13. Its pharyngeal branch forming the pharyngeal plexus (14), assisted by a branch from the glosso-pharyngeal (8), and one from the superior laryn' geal nerve (15). 16. Cardiac branches. 17. Recurrent laryngeal branch. 18. Anterior pulmonary branches. 19. Posterior pulmonary branches. 20. Oesophageal plexus. 21. Gastric 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. * Guv's Hospital Reports, vol. ii. 408 HYPOGLOSSAL NERVE. Fig. 184* Spinal Accessory Nerve. — The spinal accessory nerve arises by several filaments from the side of the 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.f Hypoglossal Nerve (lingual). The hypoglossal nerve arises from the groove between the corpus pyramidale and corpus olivare * The anatomy of the side of the neck, showing the nerves of the tongue. 1. A frag- ment of the 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 of the 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 communicans 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. &5. 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 Dy 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 die 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 hyoides. The Communicating filaments, with the gustatory nerve, are several sma I 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. 6 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. Fig. 185* 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 Ihe anterior, proceed from the posterior lateral 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 exists it is often situated within the dura mater, 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 mto 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 of the 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 Dorsal Lumbar Sacral 12 5 6 pairs. 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 thcca 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. 41] 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 of the transverse process of the 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 scapulae 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 scapuke, 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- pulae, posterior scalenus, and splenius muscle, and is covered in by the sterno-mastoid and platysma. The Branches of the cervical plexus may be arranged into three groups, superficial ascending, superficial descending; and deep— Superficial C Superficialis colli, Ascending, < Auricularis magnus, ( Occipitalis minor. Descending, » ^romiales, °' ( Claviculares. f Communicating branches, Deep J Muscular» 1 ] Communicans noni, Phrenic. 412 CERVICAL PLEXUS. The Superfirialis colli is formed by communicating branches from the second and third cervical nerves; it curves around the posterior border of the sterno-mastoid and crosses obliquely behind the external jugular vein to the anterior border of that muscle, where it divides into an ascend- ing and 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 which 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 of the upper and anterior part of the 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 middle cervical ganglion. From the second cervical nerve a large branch is given off which goes to join the spinal accessory nerve. The Muscular branches proceed frbm the third and fourth cervical nerves; they are distributed to the trapezius, levator anguli scapulae, and rhomboidei muscles. The Communicans noni is a long slender branch formed by filaments from the first, second, and third cervical nerves; it descends upon the outer side of the internal jugular vein, and forms a loop with die 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 branch from the sympathetic. It descends to the root of the neck, resting upon the scalenus anticus muscle, then crosses the first portion of the subclavian artery, and enters the chest between it and the subclavian vein. Within the chest it passes through the middle mediastinum, between die 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 die 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 which 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 nuchae, distributing muscular filaments in their course. They then pierce the aponeurosis of the trape- zius and become subcutaneous, sending branches outwards to supply the integument of the posterior aspect of the neck, and upwards to the poste- rior region of the scalp. The Ocripitalis major is the direct continuation of the second cervical nerve; it ascends obliquely inwards, between the obliquus inferior and complexus, pierces the complexus and trapezius after passing for a short distance between them, and ascends upon the posterior aspect of the head between the integument and occipito-frontalis, in company with the occi- 414 BRACHIAL PLEXUS. Fig. 1S6.» pital artery. The occipitalis majoi 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 outwards 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 of the 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 Wrisbeig 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 scapulae. The Short thoradc 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 down 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 of the 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 interna] cutaneous, and ulnar, upon its inner side; and the circumflex and mus- culo-spiral Lci.!;id. 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 hand; the internal and smaller following the direction of the supinator longus, communicating with the internal cutaneous, and at the lower third of the fore-arm sending off a twig, wiiich 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 of the fore-arm as far as the wrist and hand. The Internal Cutaneous Nerve is one of the internal and smaller of the branches of the axillary plexus; it arises from the plexus in common with the ulnar and internal head of the 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 of the 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 elbow, 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 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 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 Superfirial 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 of the 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 of the adjoining sides of the middle and ring fingers. The digital nerves in their course along the fingers are situaled 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 digital nerve divides into a palmar and a dorsal branch ; the former sup- plying 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 of the opposite side. • Nerves of front of fore-arm. I. Median nerve. 2. Anterior branch of musculo spiral or radial nerve. 3. Ulnar nerve. 4. Division of median nerve in the palm to the thumb, 1st, 2d, and radial side of 3d finger. 5. Division of ulnar nerve to ulna; ude of 3d and both sides of 4th finger. 2b Fig. 187; 418 ULNAR NERVE. The Ulnar Nerve is somewhat smaller than the median, behind wnicn 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 dowTn 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 flexor 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 of the middle third of the 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 bianch; 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 the integument and two fingers and a half on the posterior aspect hand, communicating with the internal cutaneous and radial nerve. Superfidal 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 of the radial nerve. 5, 5. A back view of the digital nerves. 6. Dorsal branch of the ulnar nerve. supply of the The 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 joih the median nerve. The Deep palmar branch passes between the abductor and flexor minimi digiti, to ihe 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 ner~ve 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 wiiole 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 gangliform 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 vertebrae, and the last between the twelfth dorsal and first lumbar. They are smaller than the lowTer 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 vertebrae, 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 inwards, crossing the semispinalis dorsi to the spinous processes of the dorsal verte- brae, 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 the first 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 spinae and communicating freely with each other they approach the surface along the outer border of the sacro-lumbalis, where diey 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 wnich 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 of the sympathetic, and pass forwards in SECOND INTERCOSTO-HUMERAL NERVE.* 421 the intercostal space with the intercostal vessels, lying below the veins ano 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 of the abdomen. The first and last dorsal nerves are exceptions to this distribution. The anterior branch of the first dorsal nerve divides into two 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 Branches of each intercostal nerve are, a muscular twig to t*ne 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- tercosto-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 of the serratus magnus muscle, and divides into filaments which 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 of the 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 dial 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 of the gluteal region as low down as the trochante* 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 vertebrae, and the last be- tween the fifth lumbar and the base of the 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 which 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 vertebrae, 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 spinae 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, Fig- ig9-* 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 vertebrae 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. P. The genito-crural nerve or spermaticus externus. 10, 10. The lower termination of •he great sympathetic. EXTERNAL CUTANEOUS NERVE. 423 The Branches of the lumbar plexus axe 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 (ilio-scrotal, ilio-hypogastricus), 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 forward 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 of the ilium, and divides into two branches, anterior and posterior. The posterior branch crosses the tensor vaginae 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 down on the anterior surface of that muscie 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 wiiich after supplying the lower border 424 CRURAL NERVE. Fig. 190.* of the internal 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 of the 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 vnder Poupart's ligament. 2. Division of the nerve into branches. 3. Femoial 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 lowTer third of the Uiigh. The Muscular branches are several large twigs which are distributed to die muscles of the anterior aspect of the thigh. One of these is sent to die rectus; one to the vastus externus, which gives off a cutaneous twig to the outer aspect of the thigh; one to the cruraeus, 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 which 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 superficial 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 wiiich 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 condyle. 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 condyle, 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 artery, and passing directly to the knee joint to supply the synovial mem- brane ; an anterior ataneous branch proceeding from the saphenous at the .16* 42G 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 of the front and outer aspect of the 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 of the psoas muscle, through the angle of bifurcation of the 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 of the 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 between 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 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 die 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 of the 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 haemorrhoidal nerve which passes through the two ischiatic openings and descends to the termination of the rectum to supply the sphincter and the integument. • A view of the branches of the ischiatic plexus to the hip and back of the 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 vaginae 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 below 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 which it is distributed. At the root of the penis this nerve gives off a cutaneous branch which runs along the side of the 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 of the 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 urinae, 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. ctitanei 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 i 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 of the 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 of the gluteus max- imus. It then passes downwards 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 of the 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 of the popliteal space, from the division of the great ischiatic nerve to the lower 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 poplitei. 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 poplitd (communicans tibialis) is a large nerve which arises from the popliteal at about the middle of its course, and de scends between die two heads of the gastrocnemius, and along the groovp 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.f 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. 2, 3. The terminations of the ramus femoralis cutaneus posterior. 4, 5. The saphenous !ierve. 6, 6. The external saphenous or communicans tibiae. t A view of the posterior tibial nerve in the back of the leg. 1 and 2, indicate it* 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 De Struc- ture Fenestras Rotunda;, et de Tympano Secundario.*' TONGUE—PAPILLAE. 467 According to Treviranus and Gottsche, the ultimate terminations of the filaments assume the form of papillae. The Arteries of the labyrinth are derived principally from the auditory branch of the superior cerebellar artery. 0 RGAN OF TASTE. The Tongue is composed of muscular fibres, which are distributed in layers arranged in various directions: thus, some are disposed longitudi- nally ; others transversely ; others, again, obliquely and vertically. Between the muscular fibres is a considerable quantity of adipose substance. The tongue is connected, posteriorly, with the os hyoides by muscular attachment; and to the epiglottis by mucous membrane, which forms the three folds called frena epiglottidis. On either side it is held in connex- ion with the lower jaw by mucous membrane, and in front a fold of that membrane, which is named frenum lingue, is formed beneath its under surface. The surface of the tongue is covered by a dense layer analogous to the corium of the skin, which gives support to papillae. A raphe marks the middle line of the organ, and divides it into symmetrical halves. The Papille of the tongue are the— Papillae circumvallatae, Papillae conicae, Papillae filiformes, Papillae fungiformes. The Papille circumvallate (p. lenticulares) are Fis- 207-* of large size, and from fifteen to twenty in number. They are situated on the dorsum of the tongue, near its root, and form a row on each side, which meets its fellow at the middle line, like the two branches of the letter A. Each papilla resembles a cone, attached by its apex to the bottom of a cup-shaped depression : hence they are also named papillae calyciformes. This cup-shaped cavity forms a kind of fossa around the papilla, whence their name circumvallate. At the meeting of the two rows of these papillae upon the middle of the root of the tongue, is a deep mucous follicle called for- amen cecum. The Papille conice and filiformes cover the whole surface of the tongue in front of the circum- vallatae, but are most abundant towards its anterior part. They are conical and filiform in shape, and many of them are pierced at the extremity by a minute aperture. Hence, they may be regarded as * The tongue with its papilla?. 1. The raphe, which in some tongues bifurcates on the dorsum of the organ, as in the figure. 2, 2. The lobes of the tongue. The rounded eminences on this part of the organ, and near its tip are the papillce fungiformes. The binaller papilkp. among which the former are dispersed, are the papilla? conicae and liliformes. 3. The tip of the tongue. 4. 4. Its sides, on which are seen the lamellated and fringed papillae. 5, 5. The A-shaped row of papillae circumvallatfe. 6. The fora men caecum. 7. The mucous glands of the root of the tongue. 8. The epiglottis. 9,9, The fraena epiglottidis." 10, 10. The greater cornua of the os hyoides. 468 ORGAN OF TOUCH. follicles rather than sentient organs; the true sentient papillae being f?x tremely minute and occupying their surface, as they do that of the othci papillae of the tongue. The Papille fungiformes (p. capitatae) are irregularly dispersed over the dorsum of the tongue, and are easily recognised among the other papillae by their rounded heads and larger size. A number of these papillae will generally be observed at the tip of the tongue. Behind the papillae circumvallatae, at the root of the tongue, are a num- ber of mucous glands, which open upon the surface. They have been im- properly described as papillae by some authors. Vessels and JYerves.—The tongue is abundantly supplied with blood by the lingual arteries. The JYerves are three in number, and of large size: The gustatory branch of the fifth, which is distributed to the papillae, and is the nerve of common sensation and taste. The glosso-pharyngeal, which is distributed to the mucous membrane, follicles, and glands of the tongue, is a nerve of sensation and motion ; it also serves to associate the tongue with the pharynx and larynx. The hypoglossal is the motor nerve of the tongue, and is distributed to the muscles. To these may be added the chorda tympani, which conveys a motor influence from the facial nerve to the lingualis muscle. The Mucous membrane wiiich invests the tongue, is continuous with the derma along the margin of the lips. On either side of the fraenum linguae it may be traced through the sublingual ducts into the sublingual glands, and along Wharton's* ducts into the submaxillary glands : from the sides of the cheeks it passes through the openings of Stenon'sf ducts to the parotid glands: in the fauces, it forms the assemblage of follicles called tonsils, and may thence be traced downwards into the larynx and pharynx, where it is continuous with the general gastro-pulmonary mucous membrane. Beneath the mucous membrane of the mouth are a number of small glandular granules, which pour their secretion upon the surface. A con- siderable number of them are situated within the lips, in the palate, and in the floor of the mouth. They are named from the position which they may chance to occupy, labial, palatal glands, &c. ORGAN OF TOUCH. The SIdn is the exterior investment of the body, which it serves to cover and protect. It is continuous at the apertures of the internal cavities with the lining membrane of those cavities, the internal skin or mucous membrane, and is composed essentially of two layers, derma and epiderma. The Derma or cutis is chiefly composed of areolo-fibrous tissue, besides which it has entering into its structure elastic and contractile fibrous tissue, together with blood-vessels, lymphatic vessels and nerves. The areolo- fibrous tissue exists in greatest abundance in the deeper stratum of the derma, which is consequently dense, white, and coarse ; the superficial * Thomas Wharton, an English physician, devoted considerable attention to the ana- •->my of the various glands; his work, entitled " Adenographia," &c., was published in 1656. ■j- Nicholas Stenon, a Danish anatomist: he was made professor in Copenhagen in 1672. STRUCTURE OF THE DERMA. 469 stratum, on the otiier hand, is fine in texture, reddish in colour, soft, raised into minute papillae, and highly vascular and sensitive. These dif- ferences in structure have given rise to a division of the derma into the deep stratum, or corium, and the superficial, or papillary layer. In the Corium the areolo-fibrous tissue is collected into fasciculi, which are small and closely interwoven in the superficial strata, large and coarse in the deep strata; in the latter forming an areolar network with large areolae, which are occupied by adipose tissue. These areolae are the channels by which the branches of vessels and nerves find a safe passage to the papillary layer, in which and in the superficial strata of the corium they are principally distributed. The yellow elastic tissue is found chiefly in the superficial strata, the red contractile tissue in the deep. It is to the latter that the nipples and scrotum owe their contractile powers, and the general surface of the skin the contraction which is known by the name of cutis anserina. The corium presents some variety in thickness in dif- ferent parts of the body. Thus in the more exposed regions, as the back, the outer sides of the limbs, the palms, and the soles, it is remarkable for its thickness; while on protected parts it is comparatively thin. On the eyelids, the penis, and the scrotum, it is peculiarly delicate. It is con- nected by its under surface with the common superficial fascia of the body. The Papillary layer of the derma is raised in the form of conical promi- nences or papillae. On the general surface of the body the papillae are short and exceedingly minute ; but in other situa- tions, as the palmar surface of the hands and fingers, and the plantar surface of the feet and toes, they are long and of large size. They also differ in arrangement; for, on the general surface they are distributed at equal distances and without order; whereas, on the palms and soles, and on the corre- sponding surfaces of the fingers and toes, they are collected into little square clumps containing from ten to twenty papillae ; and these little clumps are disposed in parallel rows. It is this arrangement in rows that gives rise to the characteristic parallel ridges and furrows which are met with on the hands and feet. The papillae in these little square clumps are for the most part uniform in size and length, but every here and there one papilla may be observed which is longer than the rest. The largest * Anatomy of a portion of skin taken from the palm of the hand. 1. The papillary layer, in which the longitudinal furrows (2) marking the arrangement of the papillae into ridges is shown. Each ridge is moreover divided by transverse furrows (3) into small quadrangular clumps. The quadrangular clumps consist of a tuft of minute conical papillae, of which one or two are frequently longer and larger than the rest. In this figure the long papilla? are alone seen, the rest being too numerous to introduce into a wood-engraving. 4. The rete mucosum raised from the papillary layer and turned back; the under surface of this stratum presents an accurate impression of the papillary layer; on which are seen longitudinal ridges corresponding with the longitudinal fur- rows, transverse ridges corresponding with the transverse furrows, and quadrangula- depressions corresponding with the quadrangular clumps of papilla?. Moreover, wher- ever one of the long papilla? exists, a distinct conical sheath will be found in the rete mucosum 5, 5. Perspiratory ducts drawn out straight by the separation of the rete mu eosum from the papillary layer; the point at which each perspiratory duct issues from the papillary layer, and pierces the rete mucosum, is the middle of the transverse furrow between the quadrangular masses. 40 470 STRUCTURE OF THE EPIDERMA. papillae of the derma are those wiiich produce the nail; in the dtrmal follicle of the nail they are long and filiform, while beneath its concave surface they form longitudinal and parallel plications which extend for nearly the entire length of that organ. In structure each papilla is com- posed of a more or less convoluted capillary and a more or less convoluted nervous loop. The Epiderma or cuticle (scarf-skin) is a product of the derma, which it serves to envelope and defend. That surface of the epiderma which is exposed to the influence of the atmosphere and exterior sources of injury is hard and horny in texture, while that which lies in contact with the papillary layer is soft and cellular. Hence the epiderma, like the derma, is divisible into two layers, external and internal, the latter being termed the rete mucosum. Moreover, the epiderma is laminated in structure, and the laminae present a progressively increasing tenuity and density as they advance from the inner to the outer surface. This difference of density is dependent on the mode of growth of the epiderma, for as the external surface is constantly subjected to destruction from attrition and chemical action, so the membrane is continually reproduced on its internal surface; new layers being successively formed on the derma to take the place of the old. The theory of growth of the epiderma, deduced from the observations of Schwann, is as follows:—A stratum of plastic lymph (liquor sanguinis) is poured out upon the surface of the derma. This fluid, by virtue of the vital force inherent in itself, and communicated to it by contact with a living tissue, is converted into granules, which are termed cell-germs, or cyto-blasts. By endosmosis, these cyto-blasts imbibe serum from the. plastic lymph and adjacent tissues, and the outermost layer or pellicle of the cyto-blast becomes gradually distended by the imbibed fluid. The cyto-blast has now become a cell, and the solid portion of the cyto-blast, which always remains adherent to some one point of the internal surface of the cell-membrane, is the nucleus of the cell. Fig. 209* Moreover, within the nucleus one or several nuclei c^==mm=^, are formed which are termed'nucleoli. By a con- s _. tinuance of the process of imbibition, the cell be- comes more or less spherical; so that, after a time, * <2iS> /fj\^. every part of the surface of the papillary layer of 3 © ^-f^/'$ J *ne derma is coated by a thin and membranous stratum, consisting of spherical cells lying closely pressed together, and corresponding with every irregularity which the papillae present. But, as this production of cells is a function constantly in operation, a new layer is formed before the first is completed, and the latter is separated by subsequent formations farther and farther from the surface of the papillary layer. As a consequence of loss of contact with the derma, the vital force is progressively dimi- * A diagram illustrative of the development of the epiderma, and of epithelia in general, according to the theory of Schwann. 1. A granule or cyto-blast. 2. The cell seen rising on the cyto-blast; the latter is now a nucleus, and a nucleolus may be de- tected in its interior. 3. The spheroidal cell. 4. The oval cell. 5. The elliptical cell. K. The flattened cell; which, by contact of its walls, is speedily converted into a scaie in which the nucleus is lost. 7. A nucleated scale as seen upon its flat surface. 8. A cluster of such scales STRUCTURE OF THE EPIDERMA. 471 nished; the cell becomes subject to the influence of physical laws, and evaporation of its fluid slowly ensues. In consequence of this evapora- tion, the cell becomes collapsed and flattened, and assumes an elliptical form ; the latter is by degrees converted into the flat cell with parallel and contiguous layers, and an included nucleolated nucleus ; and lastly, the flattened cell desiccates into a thin membranous scale, in which the nucleus is no longer apparent. My own investigations* have shown that, after the original granules of the liquor sanguinis have become aggregated into a granular nucleus, other granules are formed in successive circles, around the circumference of the nucleus, until the entire breadth of the epidermal scale is attained; that the cell never acquires a greater thickness than that of the original nucleus, and, that the formation of the scale results from the desiccation of the cell, as it is gradually pushed outwards from the derma towards the surface. Consequently, the cell never possesses any other than the flattened form ; all its phases of growth are perfected in the deepest layer of the epiderma ; and, in its internal structure, it is a parent cell containing secondary and tertiary cells and granules, its growth being the result of the growth of these secondary formations. The under surface of the epiderma is accurately modelled on the papil- lary layer of the derma, each papilla having its appropriate sheath in the newly-formed epiderma or rete mucosum, and each irregularity of surface of the former having its representative in the soft tissue of the latter. On the external surface, this character is lost; the minute elevations corre- sponding with the papillae, are, as it were, polished down, and the surface ■ is rendered smooth and uniform. The palmar and plantar surfaces of the hands and feet are, however, an exception to this rule ; for here, in con- sequence of the large size of the papillae and their peculiar arrangement in rows, ridges corresponding with the papillae are strongly marked on the superficial surface of the epiderma. The epiderma is remarkable for its thickness in situations where the papillae are large, as in the palms and soles. In other situations, it assumes a character which is also due to the nature of the surface of the derma; namely, that of being marked by a network of linear furrows, wiiich trace out the surface into small polygonal and lozenge-shaped areae. These lines correspond with the folds of the derma produced by its movements, and are most numerous where those movements are the greatest, as in the flexures and on the convexities of joints. The dark colour of the skin among the natives of the South is due to the coloration of the primitive granules of which the cell is composed, es- pecially the nucleus. As the cells desiccate, the colour of the granules is gradually lost; hence the deeper hue of the rete mucosum. The pores of the epiderma are the openings of the perspiratory ducts, hair follicles, and sebiparous glands. Vessels and JYerves.—The Arteries of the derma which enter its struc- ture through the areolae of the under surface of the corium, divide into in- numerable intermediate vessels, which form a rich capillary plexus in the superficial strata of the skin and in its papillary layer. In the papillae of some parts of the derma, as in the longitudinal plications beneath the nail, the capillary vessels form simple loops, but in other papillae they are con- voluted to a greater or less degree in proportion to the size and importance * Diseases of the Skin, 2d edition, p. 5. 472 APPENDAGES OF THE SKIN. of the papillae. The Lymphatic vessels probably form, in the superficiaj strata of the derma, a plexus, the meshes of which are interwoven widi those of the capillary and nervous plexus. No lymphatics have as yet been discovered in the papillae. The JYerves of the derma, after entering the areolae of the deeper part of the corium, divide into minute fasciculi, which form a terminal plexus in the upper strata of the corium. From this plexus the primitive fibres pass off to their distribution, as loops, in the papillae. In the less sensitive parts of the skin the loops are simple and more or less acute in their bend, in conformity with the figure of the papilla. In the sensitive parts, how- ever, and especially in the tactile papillae of the pulps of the fingers, the loop is convoluted to a greater or less extent, and acts as a multiplier of sensation. APPENDAGES OF THE SKIN. The appendages of the skin are the nails, hairs, sebiparous glands, and perspiratory glands and ducts. The Nails are horny appendages of the skin, identical in formation with the epiderma, of which they are a part. A nail is convex on its ex- ternal surface, concave within, and implanted by means of a thin margin or root in a fold of the derma (matrix), which is nearly two lines in depth, and acts the part of a follicle to the nail. At the bottom of the groove of the follicle are a number of filiform papillae, which produce the margin of • the root, and, by the successive formation of new cells, push the nail on- wards in its growth. The concave surface of the nail is in contact with the derma, and the latter is covered by papillae, which perform the double office of retaining the nail in its place, and giving it increased thickness by the addition of newly-formed cells to its under surface. It is this constant change occurring in the under surface of the nail, co-operating with the continual reproduction taking place along the margin of the root, which ensures the growth of the nail in the proper direction. The nail derives a peculiarity of appearance from the disposition and form of the papillae on the ungual surface of the derma. Thus, beneath the root, and for a short distance onwards towards its middle, the derma is covered by papillae which are more minute, and consequently less vascular than the papillae somewhat farther on. This patch of papillae is bounded by a semilunar line, and that part of the nail covering it being lighter in colour than the rest, has been termed lunula. Beyond the lunula the papillae are raised into longitudinal plaits, which are exceedingly vascular, and give a deeper tint of redness to the nail. These plait-like papillae of the derma are well calculated by their form to offer an extensive surface both for the adhesion and formation of the nail. The granules and cells are developed on every part of their surface, both in the grooves between the plaits and on their sides, and a horny lamina is formed between each pair of plaits. When the under surface of a nail is examined, these longitudinal laminae, corre- sponding with the longitudinal papillae of the ungual portion of the derma, are distintly apparent, and if the nail be forcibly detached, the laminae may be seen in the act of parting from the grooves of the papillae. It is this structure that gives rise to the ribbed appearance of the nail. The papil- lary surface of the derma which produces the nail is continuous around the circumference of the attached part of that organ with the derma of the sur- STRUCTURE OF HAIRS. 473 Fig. 210* rounding skin, and the horny structure of the nail is consequently continu- ous with that of the epiderma. Hairs are horny appendages of the skin produced by the involution and subsequent evolution of the epiderma ; the involution constituting the fol- licle in which the hair is enclosed, and the evolution the shaft of the hair. Hairs vary much in size and length in different parts of the body; in some they are so short as not to appear beyond the folli- cle ; in others they grow to a great length, as on the scalp ; while along the margins of the eyelids and in the whis- kers and beard, they are remarkable for their thickness. Hairs are generally more or less flattened in form, and when the extremity of a transverse section is examined it is found to possess an el- liptical or reniform outline. This ex- amination also demonstrates that the centre of the hair is porous and loose in texture, while its periphery is dense; thus affording ground for its division into a cortical and a medullary portion. The free extremity of a hair is generally pointed, and sometimes split into two or three filaments. Its attached extremity is implanted deeply in the integument extending through the derma into the sub-cutaneous areolar tissue, where it is surrounded by adipose cells. The central extremity of a hair is larger than its shaft, and is called the root or bulb. It is usually conical in its shape. The process of formation of a hair by its follicle is identical with that of the formation of the epiderma by the papillary layer of the derma. Plastic lymph is in the first instance exuded by the capillary plexus of the follicle, the lymph undergoes conversion, first into granules, then into cells, and the latter are elongated into fibres. The cells which are destined to form the surface of the hair go through a different process. They are converted into flat scales, which enclose the fibrous structure of the interior. These scales, as they are successively produced, overlap those which precede and give rise to the prominent and waving lines which may be seen around the circumference of a hair. It is this overlapping line that is the cause of the roughness which we experience in drawing a hair, from its point to its bulb, between the fingers. The bulb is the newly formed portion of the hair; its expanded form is due to the greater bulk of the fresh cells compared with the fibres and scales into which they are subse- quently converted in the shaft. * The anatomy of the skin. 1. The epiderma. 2. The rete mucosum or deep layer of the epiderma. 3. Two of the quadrilateral papillary clumps, such as are seen in tha palm of the hand or sole of the foot; they are composed of minute conical papilla?. 4. Ihe deep layer of the derma, the corium. 5. Adipose cells. 6. A sudoriparous gland With its spiral duct, such as is seen in the palm of the hand or sole of the foot. ". Another sudoriparous gland with a straighter duct, such as is seen in the scalp. 8 Two hairs from the scalp, enclosed in their follicles; their relative depth in the skin is preserved. 9. A pair of sebiparous glands, opening by short ducts into the follicle of the hair. 40* 93621� 474 SUDORIPAROUS GLANDS. The colour of the hair, like that of the epiderma, is due to the colora tion of the primitive granules of the cells. The Sehiparous glands are sacculated glandular organs embedded in the substance of the derma, and presenting every variety of complexity, from the simplest pouch-like follicle to the sacculated and lobulated gland. In some situations, the excretory ducts of these glands open independently on the surface of the epiderma; while in others, and the most numerous, they terminate in the follicles of the hairs. The sebiparous glands asso- ciated with the hairs are racemiform and lobulated in structure, consisting of sacculi which open by short pedunculated tubuli into a common excre- tory duct, and the latter, after a short course, terminates in the hair-follicle. In the scalp there are two of these glands to each hair-follicle. On the nose and face the glands are of large size, distinctly lobulated, and con- stantly associated with small hair-follicles. In the meatus auditorius the sebiparous (ceruminous) glands are also large and lobulated, but the largest are those of the eyelids, the Meibomian glands. The excretory ducts of sebiparous glands offer some diversity in different parts of the body: thus, in many situations they are short and straight, while in others, as in the palms of the hands and soles of the feet, where the epiderma is thick, they assume a spiral arrangement. The sebiferous ducts are lined by an inversion of the epiderma, which forms a thick and funnel-shaped cone at its commencement, but soon becomes uniform and soft. Sebi- parous glands are met with in all parts of the body, but are most abundant in the skin of the face, and in those situations which are naturally exposed to the influence of friction. The sebaceous substance, when it collects in inordinate quantities within the excretory ducts, becomes the habitat of a very remarkable parasitic animal, the steatozoon folliculorum. The Sudoriparous glands are situated deeply in the corium and also m the subcutaneous areolar tissue, where they are surrounded by adipose cells. They are small, oblong bodies, composed of one or more convo- luted tubuli, or of a congeries of globular sacs, which open into a common efferent duct. The latter ascends from the gland through the derma and epiderma, and terminates on the surface by a funnel-shaped and oblique aperture or pore. The efferent duct presents some variety in its course upwards; thus within the derma it is curved and serpentine, and if the epiderma be thin, it proceeds more or less directly to the excreting pore. Sometimes it is spirally curved within the derma, and having passed the latter, is regularly and beautifully spiral in its passage through the epi- derma, the last turn forming an oblique and valvular opening on the sur- face. The spiral course of the duct is especially remarkable in the thick epiderma of the palm of the hand and sole of the foot. On those parts of the skin where the papillae are irregularly distributed, the efferent ducts of the sudoriparous glands open on the surface also irregularly, while on the palmar and plantar surfaces of the hands and feet, the pores are situated at regular distances along the ridges, at points corresponding with the inter- vals of the small, square-shaped, clumps of papillae. Indeed, the aper- tures of the pores, seen upon the surface of the epidermal ridges, give rise to the appearance of small transverse furrows, which intersect the ridges from point to point. The efferent duct and the component sacs and tubuli of the sudoriparous gland are lined by an inflection of the epiderma. This inflection is thick OF THE VISCERA. 475 and infundirjuliform in the upper stratum of the derma, but soon becomes uniform and soft. The infundibuliform projection is drawn out from the duct when the epiderma is removed, and may be perceived on the under surface of the latter as a nipple-shaped cone. A good view of the sudo- riferous ducts is obtained by gently separating the epiderma of a portion of decomposing skin; or they may be better seen by scalding a piece of skin, and then withdrawing the epiderma from the derma. In both cases it is the lining sheath of epiderma which is drawn out from the duct. CHAPTER XI. OF THE VISCERA. That part of the science of anatomy wiiich treats of the viscera is named splanchnology, from the Greek words (Sir'ka.yyym, viscus, and Xoyo?. The viscera of the human body are situated in the three great internal cavities : cranio-spinal, thorax, and abdomen. The viscera of the cranio- spinal cavity, namely, the brain and spinal cord, with the principal organs of sense, have been already described, in conjunction with the nervous system. The viscera of the chest are : the central organ of circulation, the heart; the organs of respiration, the lungs; and the thymus gland. The abdominal viscera admit of a subdivision into those which properly beiong to that cavity, viz., the alimentary canal, liver, pancreas, spleen, kidneys, and supra-renal capsules; and those of the pelvis; the bladder and internal organs of generation. THORAX. The thorax is the conical cavity, situated at the upper part of the trunk of the body ; it is narrow above and broad below, and is bounded by the sternum, six superior costal cartilages, ribs, and intercostal muscles in front; laterally, by the ribs and intercostal muscles ; and, behind, by the same structures, and by the vertebral column, as low down as the upper border of the last rib and the first lumbar vertebra; superiorly, by the thoracic fascia and first rib ; and inferiorly, by die diaphragm. This cavity is much deeper on the posterior than on the anterior wall, in con- sequence of the obliquity of the diaphragm, and contains the heart en- closed in its pericardium, with the great vessels; the lungs, with their serous coverings, the pleurae; the oesophagus; some important nerves; and, in the foetus, the thymus gland. THE HEART. The central organ of circulation, the heart, is situated between the two layers of pleura which constitute the mediastinum, and is enclosed in a proper membrane, the pericardium. Pericardium,.—The pericardium is a fibro-serous membrane like the dura mater, and resembles that membrane in deriving its serous layer from the reflected serous membrane of the viscus which it encloses. It consists, therefore, of two layers, an external fibrous and an internal serous. The 476 THE HEART. fibrous layer is attached, above, to the great vessels at the coot of the heart, where it is continuous with the thoracic fascia; and below, to the tendinous portion of the diaphragm. The serous membrane invests the heart with the commencement of its great vessels, and is then reflected upon the internal surface of the fibrous layer. Fig. 211.* The Heart is placed obliquely in the chest, the base being directed up- wards and backwards towards the right shoulder; the apex forwards and to the left, pointing to the space be- tween the fifth and sixth ribs, at about two or three inches from the sternum. Its under side is flattened, and rests upon the tendinous portion of the dia- phragm ; its upper side is rounded and convex, and formed principally by the right ventricle, and partly by the left. Surmounting the ventricles are the corresponding auricles, whose auricu- lar appendages are directed forwards, and slightly overlap the root of the pulmonary artery. The pulmonary artery is the large anterior vessel at the root of the heart; it crosses ob- liquely the commencement of the aorta. The heart consists of two auri- cles and two ventricles, which are respectively named, from their position, right and left. The right is the venous side of the heart; it receives into its auricle the venous blood from every part of the body, by the superior and inferior cava and coronary vein. From the auricle the blood passes into the ventricle, and from the ventricle through the pulmonary artery, to the capillaries of the lungs. From these it is returned as arterial blood to the left auricle ; from the left auricle it passes into the left ventricle; and * The anatomy of the heart. 1. The right auricle. 2. The entrance of the superior vena cava. 3. The entrance of the inferior cava. 4. The opening of the coronary vein, half closed by the coronary valve. 5. The Eustachian valve. 6. The fossa ovalis, surrounded by the.annulus ovalis. 7. The tuberculum Loweri. 8. The musculi pecti- nati in the appendix auricula?. 9. The auriculo-ventricular opening. 10. The cavity of the right ventricle. 11. The tricuspid valve, attached by the chorda? tendinea? to the carnea? columnse (12). 13. The pulmonary artery, guarded at its commencement by three semilunar valves. 14. The right pulmonary artery, passing beneath the arch and behind the ascending aorta. 15. The left pulmonary artery, crossing in front of the de scending aorta. * The remains of the ductus arteriosus, acting as a ligament between the pulmonary artery and arch of the aorta. The arrows mark the course of the venous blood through the right side of the heart. Entering the auricle by the superior and in ferior cava?, it passes through the auriculo-ventricular opening into the ventricle and thence through the pulmonary artery to the lungs. 16. The left auricle. 17. The open ings of the fourth pulmonary veins. 18. The auriculo-ventricular opening. 19. The left ventricle. 20. The mitral valve, attached by its chorda? tendinea? to two large co- Jumna? carnea?, which project from the walls of the ventricle. 21. The commencement and course of the ascending aorta behind the pulmonary artery, marked by an arrow. The entrance of the vessel is guarded by three semilunar valves. 22. The arch of the aorta. The comparative thickness of the two ventricles is shown in the diagram. The course of the pure blood through the left side of the heart is marked by arrows. Tho blood is brought from the lungs by the four pulmonary veins into the left auricle, and passes through the auriculo-ventricular opening into the left ventricle, whence it is con veyed by the aorta to eveyy part of the body. RIGHT AURICLE. 477 from the left ventricle is carried through the aorta, to be distributed to every part of the body, and again returned to the heart by the veins This constitutes the course of the adult circulation. The heart is best studied in situ. If, however, it be removed from the body, it should be placed in the position indicated in the above descrip- tion of its situation. A transverse incision should then be made along the ventricular margin of the right auricle, from the appendix to its right border, and crossed by a perpendicular incision, carried from the side of the superior to the inferior cava. The blood must then be removed. Some fine specimens of white fibrin are frequently/ound with the coagula; occasionally they are yellow and gelatinous. This appearance deceived the older anatomists, who called these substances "polypus of the heart:" they are also frequently found in the right ventricle, and sometimes in the left cavities. The Right Auricle is larger than the left, and is divided into a prin- cipal cavity or sinus, and an appendix auriculae. The interior of the sinus presents for examination five openings ; two valves ; two relicts of foetal structure; and two peculiarities in the proper structure of the auricle. They may be thus arranged:— ' Superior cava, Inferior cava, Openings.....< Coronary vein, Foramina Thebesii, Auriculo-ventricular opening. fT , ( Eustachian valve, Valves......\ n , ' ( Coronary valve. „,. . r - . , , , \ Annulus ovalis, Relicts of foetal structure < ^ r J J ( r ossa ovalis. a, , /..7 •/ { Tuberculum Loweri, structure of t/ie auricle . < AT ,- .• .. ' J ( Musculi pectmati. The Superior cava returns the blood from the upper half of the body, and opens into the upper and front part of the 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 vdn 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 of the 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 ht* name is contained in his " Dissertatio Medica de Circulo Sanguinis in Corde,'' 170S. 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 the septum auricularum, opposite the termination of the inferior cava. It is the rounded margin of the 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 auricula?, in the cavity of which the musculi pectinati are seen. 3. The superior vena cava, opening into the upper part of the 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 columna? carnea? 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 and right curtains of the tricuspid valve are connected by the chorda? tendinea?. h. The " long moderator band." i. The two columna? carnea? of the right curtain, k. The at tachment by chorda? tendineap of the left limb of the anterior curtain. I, I. Chorda? ten dinta; 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 auricula?, 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. * Richard Lower, 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 tl an to man. Fig. 212.J 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 between 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 columnae. 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 of the 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 chorde tendinee are the tendons of the thick muscular columns (columne carnee) which stand out from the walls 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 auricle 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 * " F.s caecum and colon. In the descending colon the posterior bands usually unite and form a single band. From this point the bands are continued down- wards upon the sigmoid flexure to the rectum, around which they spread out and form a thick and very muscular longitudinal layer. The circular fibres in the caecum and colon are exceed- ingly thin; in the rectum they are thicker, and at its lower extremity they are aggregated into the thick mus- cular ring which is known as the internal sphincter ani. Between the latter and the mucous membrane are several narrow fasciculi of longitudi- nal muscular fibres, somewhat more than an inch in length, which have been described by Horner of Philadelphia. M;-m Serous Coat.—The pharynx and oesophagus have no covering of serous membrane. The alimentary canal within the abdomen has a serous layer, derived from the peritoneum. * A vertical section of the parietes of the anus, passing through the middle line of one of the columns of the rectum, and the neighbouring parts. 1. The internal sphincter, with its arched fibres transversely divided. 2, 2. The plane of arched fibres of the muscular coat, similarly divided. 3. The point of greatest contraction of the internal sphincter. 4. The external sphincter. 5. The point of greatest contraction of the same muscle. 6. The plane of longitudinal fibres of the muscular coat, longitudinally divided. 7. Some of these fibres terminating in the internal sphincter. 8. Others, terminating in the external sphincter. 9. The remaining longitudinal fibres, collected into a semiten- dinous fasciculus, passing over the lower margin of the internal sphincter, to be reverted ipward within the duplicature of the column. 10. These reverted fibres again becom- ing muscular, and terminating in the mucous coat. 11. The mucous coat. 12. A bristle in one or the sacs.—G. THE LIVER. 515 The Stomach is completely surrounded by peritoneum, excepting along the line of junction of the great and lesser omentum. The first or oblique portion of tire duodenum is also completely included by the serous mem- brane, with the exception of the points of attachment of the omenta. The descending portion has merely a partial covering on its anterior surface. The transverse portion is also behind the peritoneum, being situated be- tween the two layers of the transverse meso-colon, and has but a partial covering. The rest of the small intestine is completely invested by it, excepting along the concave border to which the mesentery is attached. The cecum is more or less invested by the peritoneum, the more frequent disposition being that in which the intestine is surrounded for three-fourths only of its circumference. The ascending and the descending colon are covered by the serous membrane only in front. The transverse colon is invested completely, with the exception of the lines of attachment of the greater omentum and transverse meso-colon. And the sigmoid flexure is entirely surrounded, with the exception of the part corresponding with the junction of the left meso-colon. The upper third of the rectum is com- pletely enclosed by the peritoneum; the middle third has an anterior covering only, and the inferior third none whatsoever. Vessels and JYerves.—The Arteries of the alimentary canal, as they supply the tube from above downwards, are the pterygo-palatine, ascend- ing pharyngeal, superior thyroid, and inferior thyroid, in the neck; oeso- phageal, in the thorax ; gastric, hepatic, splenic, superior and inferior mesenteric, in the abdomen; and inferior mesenteric, iliac, and internal pudic, in the pelvis. The veins from the abdominal alimentery canal unite to form the vena portae. The lymphatics and lacteals open into the thoracic duct. The JYerves of the pharynx and oesophagus are derived from the glosso- pharyngeal, pneumogastric, and sympathetic. The nerves of the stomach are the pneumogastric, and sympathetic branches from the solar plexus; and those of the intestinal canal are the superior and inferior mesenteric and hypogastric plexuses. The extremity of the rectum is supplied by the inferior sacral nerves from the spinal cord. THE LIVER. The liver is a conglomerate gland of large size, appended to the'ali- mentary canal, and performing the double office of separating impurities from the venous blood of the chylo-poietic viscera previously to its return into the general venous circulation, and of secreting a fluid necessary to chylification, the bile. It is the largest organ in the body, weighing about four pounds, and measuring through its longest diameter about twelve inches. It is situated in the right hypochondriac region, and extends across the epigastrium into the left hypochondriac, frequently reaching, by its left extremity, the upper end of the spleen. It is placed obliquely in the abdomen ; its convex surface looking upwards and forwards, and the concave downwards and backwards. The anterior border is sharp and free, and marked by a deep notch, and the posterior rounded and broad. It is in relation, superiorly and posteriorly, with the diaphragm ; and infe- riorly, with the stomach, ascending portion of the duodenum, transverse colon, right supra-renal capsule, and right kidney; and corresponds, by its free border, with the lower margin of the ribs. 51G LIGAMENTS OF THE LIVER. Ligaments.—The liver is retained in its place by five ligaments ; four of which are duplicatures of the peritoneum, and are situated on the con- vex surface of the organ; the fifth is a fibrous cord which passes through a fissure in its under surface, from the umbilicus to the inferior vtna cava. They are the— Longitudinal, Coronary, Two lateral, Round. The Longitudinal ligament (broad, ligamentum suspensorium hepatis is an antero-posterior fold of peritoneum, extending from the notch on the anterior margin of the liver to its posterior border. Between its two layers in the anterior and free margin, is the round ligament. The Lateral ligaments are formed by the twTo layers of peritoneum, which pass from the under surface of the diaphragm to the posterior border of the liver; they correspond with its lateral lobes. The Coronary ligament is formed by the separation of the two layers forming the lateral ligaments near their point of convergence. The poste- rior layer is continued unbroken from one lateral ligament into the other; but the anterior quits the posterior at each side, and is continuous with the corresponding layer of the longitudinal ligament. In this way a large oval surface on the posterior border of the liver is left uncovered by peritoneum, and is connected to the diaphragm by areolo-fibrous tissue. This space is formed principally by the right lateral ligament, and is pierced near its left extremity by the inferior vena cava, previously to the passage of that vessel through the tendinous opening in the diaphragm. The Round ligament is a fibrous cord resulting from the obliteration of the umbilical vein, and situated between the two layers of peritoneum in the anterior border of the longitudinal ligament. It may be traced from the umbilicus, along the longitudinal fissure of the under surface of the liver to the inferior vena cava, to which it is connected. / Fissures.—The under surface of the liver is marked by five fissures, < • The upper surface of the liver. 1. The right lobe. 2. The left lobe. 3. The ante- rior or free border. 4. The posterior or rounded border. 5. The broad ligament. 6. The round ligament. 7, 7. The two lateral ligaments. 8. The space left uncovered by Ihe peritoneum, and surrounded by the coronary ligament. 9. The inferior vena cava. 10. The point of the lobus Spigelii. 3. The fundus of the gall-bladder seen projecting beyond the anterior border of the right lobe. FISSURES OF THE LIVER. 517 which divide its surface into five compartments or lobes, two principal and tnree minor lobes ; they are the— Fissures. Lobes. Longitudinal fissure, Right lobe, \ Fissure of the ductus venosus, Left lobe, \ i Transverse fissure, Lobus quadratus, Fissure for the gall-bladder, Lobus Spigelii, ^Fissure for the vena cava. Lobus caudatus. The Longitudinal fissure is a deep groove running from the notch upon the anterior margin of the liver, to the posterior border of the organ. At about one-third from its posterior extremity it is joined by a short but deep fissure, the transverse, which meets it transversely from the under part of the right lobe. The longitudinal fissure in front of this junction lodges the fibrous cord of the umbilical vein, and is generally crossed by a band of hepatic sub- stance called the pons hepatis. The Fissure for the ductus venosus is the shorter portion of the longitu- dinal fissure, extending from the junctional termination of the transverse fissure to the posterior border of the liver, and containing a small fibrous cord, the remains of the ductus venosus. This fissure is therefore but a ■ part of the longitudinal fissure. .:) • Vy Figv227* I ■#/-£ '&U> The Transverse fissure is the short and deep fissure, about two inches in length, through which the hepatic ducts, hepatic artery, and portal vein enter the liver. Hence this fissure'was considered by the older anatomists as the gate (porta) of the liver; and the large vein entering the organ at * The under surface of the liver. 1. The right lobe. 2. The left lobe. 3. The lobus quadratus. 4. The lobus Spigelii. 5. The lobus caudatus. 6. The longitudinal fissure; the numeral is placed on the rounded cord, the remains of the umbilical vein. 7. The pons hepatis. 8. The fissure for the ductus venosus; the obliterated cord of the ductus is seen passing backwards to be attached to the coats of the inferior vena cava (9). 10. The gall-bladder lodged in its fossa. 11. The transverse fissure, containing, from before backwards, the hepatic duct, hepatic artery, and portal vein. 12. The vena cava. 13. A depression corresponding with the curve of the colon. 14. A double de- pression produced by the right kidney and its supra-renal capsule. 15. The rough sur face on the posterior border of the liver left uncovered by peritoneum ; the cut edge of peritoneum surrounding this surface forms part of the coronary ligament. 16. Tha notch on the anterior border, separating the two lobes. 17. The notch on the posterior border, corresponding with the vertebral column. 44 51S 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 a notch. The Fissure for the vena cava is a deep and short fissure, occasionally / a circular tunnel, which proceeds from a little behind the right extremity i of the transverse fissure to the posterior border of the liver, and lodges the y 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 surface by the transverse fissure, and by the fissures for the gall- bladder and vena cava; and presents three depressions, one, in front, for the curve of the ascending colon, and two, behind, for the right supra- renal capsule and kidney. The Left lobe is small and flattened, convex upon its upper surface, and concave below, where it lies in contact with the anterior surface of the stomach. It is sometimes in contact by its extremity widi the upper end of the spleen, and is in relation, by its posterior border, with the cardiac 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 ■i liver; behind, by the transverse fissure ; to the right, by the gall-bladder; v^nd 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. V^ 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 4 separate 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 y, marked, in others it is small and ill-defined. v 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 JYerves.—The vessels entering into the structure of the liver are also 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. 51 y 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 pan of the organ; so that their general direction is from below upwards, and from the centre towards the circumference. The Hepatic vdns commence at the circumference, and proceed from before 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 die 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, todistin- 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 JYerves of the liver are derived from the systems both of animal and organic life ; the former proceed from the right phrenic and pneumo- gastric nerves, and the latter from the hepatic plexus. Structure and Minute Anatomy of the Liver. The Liver is composed of lobules, of a connecting metlium called Glis- son's capsule, of the ramifications of the portal vdn, hepatic duct, hepatic artery, hepatic veins, lymphatics, and nerves, and is enclosed and retained in its situation by the peritoneum. The Lobules are small granular bodies, of about the size of a millet seed, of an irregular form, and presenting a number of rounded promi- Fig. 229.f * The lobules of the liver. The lobules as they are seen upon the surface of the liver, or when divided transversely. 1. The intralobular vein in the centre of each lobule. 2. The interlobular fissure. 3. The interlobular space. | A longitudinal section of two lobules. 1. A superficial lobule, terminating abruptly, »nd resembling a section at its extremity. 2. A deep lobule, showing the foliated ap- pearance of its section. 3. The interlobular vein, with its converging venules; the vein terminates in a sublobular vein. 4. The external, or capsular surface of the lobule Fig. 228* 520 STRUCTURAL ANATOMY OF THE LIVER. nences on their surface. When divided longitudinally, they have a foli- ated appearance, and transversely, a polygonal outline, with sharp or rounded angles, according to the smaller or greater quantity of Glisson's capsule contained in the liver. Each lobule is divided upon its exterior into a base and a capsular surface. The base corresponds with one ex- tremity of the lobule, is flattened, and rests upon an hepatic vein, which is thence named sublobular. The capsular surface includes the rest of the periphery of the lobule, and has received its designation from being en- closed in an areolar capsule derived from the capsule of Glisson. In the centre of each lobule is a small vein, the intralobular, which is formed by the convergence of six or eight minute venules from the rounded promi- nences of the periphery. The intralobular vein thus constituted takes its course through the centre of the longitudinal axis of the lobule, pierces the middle of its base, and opens into the sublobular vein. The periphery of the lobule, with the exception of its base, which is always closely at- tached to a sublobular vein, is connected by means of its areolar capsule with the capsular surfaces of surrounding lobules. The interval between the lobules is the interlobular fissure, and the angular interstices formed by the apposition of several lobules are the interlobular spaces. The lobules of the centre of the liver are angular, and somewhat smaller than those of the surface, from the greater compression to which they are submitted. The superficial lobules are incomplete, and give to the sur- face of the organ the appearance and all the advantages resulting from an examination of a transverse section. " Each lobule is composed of a plexus of biliary ducts, of a venous plexus, formed by branches of the portal vein, of a branch (intralobular), of an hepatic vein, and of minute arteries; nerves and absorbents, it is to be pre- sumed, also enter into their formation, but cannot be traced into them." " Examined with the microscope, a lobule is apparently composed of nume- rous minute bodies of a yellowish colour and of various forms, connected with each other by vessels. These minute bodies are the adni of Malpighi." "If an uninjected lobule be exa- mined and contrasted with an injected lobule, it will be found that the acini of Malpighi in the former are identi- cal with the injected lobular biliary plexus in the latter, and the blood- vessels in both will be easily distin- guished from the ducts."f Glisson's capsule is the areolo- fibrous tissue which envelopes the he- patic artery, portal vein, and hepatic duct, during their passage through the right border of the lesser omentum, and which continues to surround them to their ultimate distribution in the substance of the lobules. It forms for • Horizontal section of three superficial lobules, showing the two principal systems oi blood-vessels.—(Kiernan.) -j- The Anatomy and Physiology of the Liver, by Mr. Kiernan, Phil. Trans. 1833, Irom which this and 'he other paragraphs within inverted commas, on the structure of the liver, are quoted Fig. 230* STRUCTURAL ANATOMY OF THE LIVER. 521 each lobule a distinct capsule, which invests it on all sides with the ex- ception of its base, connects all the lobules together, and constitutes the proper capsule of the entire organ. But Glisson's capsule is not mere areolar tissue; " it is to the liver what the pia mater is to the brain ; it is a cellulo-vascular membrane, in which the vessels divide and subdivide to an extreme degree of minuteness; which lines the portal canals, forming sheaths for the larger vessels contained in them, and a web in which the smaller vessels ramify; which enters the interlobular fissures, and with the vessels forms the capsules of the lobules; and which finally enters the lobules, and with the-blood-vessels expands itself over the secreting biliary ducts." Hence arises a natural division of the capsule into three portions, a v ginal, an interlobular, and a lobular portion. The vaginal portion is that which invests the hepatic artery, hepatic duct, and portal vein, in the portal canals; in the larger canals it com- pletely surrounds these vessels, but in the smaller is situated only on that side which is occupied by the artery and duct. The interlobular portion occupies the interlobular fissures and spaces, and the lobular portion forms the supporting tissue to the substance of the lobules. The Portal vdn, entering the liver at the transverse fissure, ramifies through its structure in canals, which resemble, by their surfaces, the ex- ternal superficies of the liver, and are formed by the capsular surfaces of the lobules. These are the portal canals, and contain, besides the portal vein with its ramifications, the artery and duct with their branches. In the larger canals, the vessels are separated from the parietes by a web of Glisson's capsule ; but, in the smaller, the portal vein is in contact with the surface of the canal for about two-thirds of its cylinder, the oppo- site third being in relation with the artery and duct and their investing capsule. If, therefore, the portal vein were laid open by a longitudinal incision in one of these smaller canals, the coats being transparent, the outline of the lobules, bounded by their interlobular fissures, would be as distinctly seen as upon the external surface of the liver, and the smaller venous branches would be observed entering the interlobular spaces. The branches of the portal vein are, the vaginal, interlobular, and Fis- 231-* lobular. The vaginal branches a z are those which, being given off aic muoc vihilii, ucmg given uu /'.ftSA. v; ]v_ in the portal canals, have to pass z \^ ,'*iM f^ through the sheath (vagina) of p- iff1 Glisson's capsule, previously to &MSS0MM/ entering the interlobular spaces. ^o*«v Wr$ i'i^f-f^'' In this course they form an intri- z^%^ 'u> V» V\ cate plexus, the vaginal plexus, vj^|v which, depending for its exist- VjjSS? \, ■',!^3 ence on the capsule of Glisson, i^Si necessarily surrounds the vessels, as does that capsule in the larger canals, and occupies the capsular side only in the smaller canals. The interlobular branches are given off from die vaginal portal plexus where it exists, and directly from the portal veins, in that part of the smaller canals where the coats of the vein are in contact with the walls of the canal. They then enter the interlobular * Horizontal section of two superficial lobules, showing interlobular plexus of biliary ducts.—(Kiernan.) 44* 522 STRUCTURAL ANATOMY OF THE LIVER. spaces and divide into branches, which cover with their ramifications every part of the surface of the lobules, with the exception of their bases and those extremities of the superficial lobules which appear upon the surfaces of the liver. The interlobular veins communicate freely with each other, and with the corresponding veins of adjoining fissures, and establish a general portal anastomosis throughout the entire liver. The lobular branches are derived from the interlobular veins; they form a plexus with- in each lobule, and converge from the circumference towards the centre, where they terminate in the minute radicles of the intralobular vein. " This plexus, interposed between the interlobular portal veins and the intralobular hepatic vein, constitutes the venous part of the lobule, and may be called the lobular venous plexus." The irregular islets of the sub- stance of the lobules, seen between the meshes of this plexus by means of the microscope, are the acini of Malpighi, and are portions of the lobular biliary plexus. The portal vein returns the venous blood from the chylopoietic viscera, to be circulated through the lobules; it also receives the venous blood which results from the distribution of the hepatic artery. The Hepatic duct, entering the liver at the transverse fissure, divides into branches, which ramify through the portal canals, with the portal vein and hepatic artery, to terminate in the substance of the lobules. Its branches, like those of the portal vein, are vaginal, interlobular, and lobular. The Vaginal branches ramify through the capsule of Glisson, and form a vaginal biliary plexus, which, like the vaginal portal plexus, surrounds the vessels in the large canals, but is deficient on that side of the smaller canals near which the duct is placed. The branches given off by the vaginal biliary plexus are interlobular and lobular. The interlobular branches proceed from the vaginal biliary plexus where it exists, and directly from the hepatic duct on that side of the smaller canals against which the duct is placed. They enter the interlobular spaces, and ramify upon the capsular surface of the lobules in the interlobular fissures, where they communicate freely with each other. The lobular ducts are derived chiefly from the interlobular; but to those lobules forming the walls of the portal canals, they pass directly from the vaginal plexus. They enter the lobule, and form a plexus in its interior, the lobular biliary plexus, which constitutes the principal part of the substance of the lobule. The ducts terminate either in loops or in caecal extremities. The coats of the ducts are very vascular, and are supplied with a num- ber of mucous follicles, wiiich are distributed irregularly in the larger, but are arranged in two parallel longitudinal rows in the smaller ducts. The Hepatic artery enters the liver with the portal vein and hepatic duct, and ramifies with those vessels through the portal canals. Its branches are the vaginal, interlobular, and lobular. The vaginal branches, like those of the portal vein and hepatic duct, form a vaginal plexus, which exists throughout the whole extent of the portal canals, with the exception of that side of the smaller canals which corresponds with the artery. The interlobular branches, arising from the vaginal plexus and from the parietal side of the artery (in the smaller canals), ramify through the interlobular fissures, and are principally distributed to the coats of the interlobular ducts. " From the superficial interlobular fissures small arteries emerge, and STRUCTURAL ANATOMY OF THE LIVER. 523 ramify in the proper capsule, on the convex and concave surface of the liver, and in the ligaments. These are the capsular arteries." Where the capsule is well developed, " these vessels cover the surfaces of the liver with a beautiful plexus," and " anastomose with branches of the phrenic, internal mammary, and supra-renal arteries," and with the epi- gastric. The Lobular branches, extremely minute and few in number, are the nutrient vessels of the lobules, and terminate in the lobular venous plexus. All the venous blood resulting from the distribution of the hepatic artery, even that from the vasa vasorum of the hepatic veins, is returned into the portal vein. The Hepatic veins commence in the substance of each lobule by minute venules, which receive die blood from the lobular venous plexus, and converge to form the intralobular vein. The intralobular vdn passes through the central axis of the lobule, and through the middle of its base, to terminate in a sublobular vein ; and the union of the sublobular veins constitutes the hepatic trunks, which open into the inferior vena cava. The hepatic venous system consists, therefore, of three sets of vessels; intralobular veins, sublobular veins, and hepatic trunks. The Sublobular vdns are contained in canals formed solely by the bases of the lobules, with which, from the absence of Glisson's capsule, they are in immediate contact. Their coats are thin and transparent; and, if they be laid open by a longitudinal incision, the bases of the lobules will be distinctly seen, separated by interlobular fissures, and perforated through the centre by the opening of the intralobular vein. The Hepatic trunks are formed by the union of the sublobular veins; they are contained in canals (hepatic-venous) similar in structure to the portal canals, and lined by a prolongation of the proper capsule. They proceed from before backwards, and terminate, by two large openings (corresponding to the right and left lobe of the liver) and several smaller apertures, in the inferior vena cava. Summary.—The liver has been shown to be composed of lobules; the lobules (excepting at their bases) are invested and connected together, the vessels supported, and the whole organ enclosed, by Glisson's capsule, and they are so arranged, that the base of every lobule in the liver is in contact with an hepatic vein (sublobular). The Portal vein distributes its numberless branches through portal canals, which are channeled through every part of the organ; it brings the returning blood from the chylopoietic viscera; it collects also the venous blood from the ultimate ramifications of the hepatic artery in the liver itself. It gives off branches in the canals, which are called vaginal, and form a venous vaginal plexus; these give off interlobular branches, and the latter enter the lobules and form lobular venous plexuses, from the blood circulating in which the bile is secreted. The Bile in the lobule is received by a network of minute ducts, the lobular biliary plexus; it is conveyed from the lobule into the interlobular ducts; it is thence poured into the biliary vaginal plexus of the portal canals, and thence into the excreting ducts, by which it is carried to the duodenum and gall-bladder, after being mingled in its course with the mucous secretion from the numberless muciparous follicles in the walls of the ducts. The Hepatic artery distributes branches through every portal canal; 524 STRUCTURAL ANATOMY OF THE LIVER. gives off vaginal branches which form a vaginal hepatic plexus, from which the interlobular branches arise, and these latter terminate ultimately in the lobular venous plexuses of the portal vein. The artery ramifies abundantly in the coats of the hepatic ducts, enabling them to provide their mucous secretion; and supplies the vasa vasorum of the portal and hepatic veins, and the nutrient vessels of the entire organ. The Hepatic vdns commence in the centre of each lobule by minute radicles, which collect the impure blood from the lobular venous plexus and convey it into the intralobular vdns ; these open into the sublobular veins, and the sublobular veins unite to form the large hepatic trunks by which the blood is conveyed into the vena cava. Physiological and Pathological Deductions. — The physiological deduc- tion arising out of this anatomical arrangement is, that the bile is wholly secreted from venous blood, and not from a mixed venous and arterial blood, as stated by Midler; for although the portal vein receives its blood from two sources, viz. from the chylopoietic viscera arid from the capil- laries of the hepatic artery, yet the very fact of the blood of the latter vessel having passed through its capillaries into the portal vein, or in ex- tremely small quantity into the capillary network of the lobular venous plexus, is sufficient to establish its venous character.* The pathological deductions depend upon the following facts: —Each lobule is a perfect gland; of uniform structure, of uniform colour, and possessing the same degree of vascularity throughout. It is the seat of a double venous circulation, the vessels of the one (hepatic) being situated in the centre of the lobule, and those of the other (portal) in the circum- ference. Now the colour of the lobule, as of the entire liver, depends chiefly upon the proportion of blood contained within these two sets of vessels; and so long as the circulation is natural, the colour will be uni- form. But the instant that any cause is developed which shall interfere with the free circulation of either, there will be an immediate diversity in the colour of the lobule. Thus, if there be any impediment to the free circulation of the venous blood through the heart or lungs, the circulation in the hepatic veins will be retarded, and the sublobular and the intralobular veins will become congested, giving rise to a more or less extensive redness in the centre of each of the lobules, while the marginal or non-congested portion presents a distinct border of a yellowish white, yellow, or green colour, according to the quantity and quality of the bile it may contain. " This is ' passive congestion' of the liver, the usual and natural state of the organ after death;" and, as it commences with the hepatic vein, it may be called the first stage of hepatic-venous congestion. But if the causes which produced this state of congestion continue, or be from the beginning of a more active kind, the congestion will extend through the lobular venous plexuses " into those branches of the portal vein situated in the interlobular fissures, but not to those in the spaces, which being larger, and giving origin to those in the fissures, are the last to be congested." In this second stage the liver has a mottled appear- ance, the non-congested substance is arranged in isolated, circular, anr7 ramose patches, in the centres of which the spaces and parts of the fissures are seen. This is an extended degree of hepatic-venous congestion; it is * For arguments on this contested question, see the article "Liver." in the " Cyclo jiaedia of Anatomy and Physiology," edited by Dr. Todd. GALL-BLADDER. 525 " active congestion" of the liver, and very commonly attends disease of the heart and lungs. These are instances of partial congestion, but there is sometimes general congestion of the organ. " In general congestion the whole liver is of a red colour, but the central portions of the lobules are usually of a deeper hue than the marginal portions." GALL-BLADDER. The Gall-bladder (fig. 166) is the reservoir of the bile ; it is a pyriform sac, situated in a fossa on the under surface of the right lobe of the liver, and extending from the right extremity of the transverse fissure to the free margin. It is divided into a body, fundus, and neck: the fundus or broad extremity in the natural position of the liver is placed downwards, and ' frequently projects beyond the free margin of the liver, while the neck, small and constricted, is directed upwards. This sac is composed of three ^ coats, serous, fibrous, and mucous. The serous coat is partial, is derived \ from the peritoneum, and covers that side only wiiich is unattached to the j liver. The middle or fibrous coat is a thin but strong fibrous layer, con- / nected on one side to the liver, and on the other to the peritoneum. The ^ internal or mucous coat is but loosely attached to the fibrous layer; it is \ everywhere raised into minute rugae, wiiich give it a beautifully reticulated-7 \ appearance, and forms, at the neck of the sac, a spiral valve. It is con- tinuous through the hepatic duct with the mucous membrane lining all the ducts of the liver, and through the ductus communis choledochus, with the mucous membrane of the alimentary canal. The Biliary ducts are, the ductus communis choledochus, the cystic, and the hepatic duct. The Ductus communis choledochus (x^v bilis, <5s'^o,aa» recipio) is the common excretory duct of the liver and gall-bladder; it is about three inches in length, and commences at the papilla situated on the inner side of the cylinder of the perpendicular portion of the duodenum. Passing obliquely between the mucous and muscular coat, it ascends behind the duodenum, and through the right border of the lesser omentum ; and divides into two branches, the cystic duct and the hepatic duct. It is constricted at its commencement in the duodenum, and becomes dilated in its progress upwards. The Cystic duct, about an inch in length, passes outwards from the /preceding to the neck of the gall-bladder, with which it is continuous. The Hepatic duct continues onwards to the transverse fissure of the liver, and divides into two branches, which ramify through the portal canals to every part of the liver. The coats of the hepatic ducts are an external or fibrous, and an internal or raucous coat. The external coat is composed of a contractile fibrous tissue, which is probably muscular; but its muscularity has not yet been demonstrated in the human subject. The mucous coat is continuous on the one hand with the lining membrane of the hepatic ducts and gall bladder, and on the other with that of the duodenum. Vessels and JYerves. — The gall-bladder is supplied with blood by the cystic artery, a branch of the hepatic. Its veins return their blood into the portal vein. The nerves are derived from the hepatic plexus. r>2fi PANCREAS—SPLEEN. THE PANCREAS. The pancreas is a long, flattened, conglomerate gland, analogous to the salivary glands. It is about six inches in length, and between three ind four ounces in weight; is situated transversely across the posterior wall of the abdomen, behind the stomach, and resting on the aorta, venaportae, inferior vena cava, the origin of the superior mesenteric artery, and the left kidney and supra-renal capsule; opposite the first and second lumbar vertebrae. It is divided into a body, a greater and a smaller extremity: the great end or head is placed towards the right, and is surrounded by the curve of the duodenum ; the lesser end extends to the left as far as the spleen. The anterior surface of the body of the pancreas is covered by the ascending posterior layer of peritoneum, and is in relation with the stomach, the first portion of the duodenum, and the commencement of the transverse arch of the colon. The posterior surface is grooved for the splenic vein, and tunnelled by a complete canal for the superior mesenteric and portal vein, and superior mesenteric artery. The upper border pre- sents a deep groove, sometimes a canal, for the splenic artery and vein, and is in relation with the oblique portion of the duodenum, the lobus Spigelii, and cceliac axis. And the lower border is separated from the transverse portion of the duodenum by the superior mesenteric artery and vein. Upon the posterior part of the head of the pancreas is a lobular fold of the gland which completes the canal of the superior mesenteric vessels, and is called the lesser pancreas. In structure, the pancreas is composed of reddish-yellow polyhedral lobules ; these consist of smaller lobules, and the latter are made up of the arborescent ramifications of minute ducts, terminating in caecal pouches. The pancreatic duct commences at the papilla on the inner and posterior surface of the perpendicular portion of the duodenum by a small dilatation which is common to it and the ductus communis choledochus, and, pass- ing obliquely between the mucous and muscular coats, runs from right to left through the middle of the gland, lying nearer its anterior than its pos- terior surface. At about the commencement of the apicial third of its course it divides into twTo parallel terminal branches. The duct gives off numerous small branches, which are distributed through the lobules, and constitute, with the latter, the substance of the gland. The duct which receives the secretion from the lesser pancreas is called the ductus pancre- aticus minor; it opens in the principal duct neai the duodenum, and some- times passes separately into that intestine. As a variety, two pancreatic ducts are occasionally met with. Vessels and JYerves.—The arteries of the pancreas are branches of the splenic, hepatic, and superior mesenteric; the vdns open into the splenic vein ; the lymphatics terminate in the lumbar glands. The nerves are fila- ments of the splenic plexus. THE SPLEEN. The spleen is an oblong flattened organ, of a dark bluish-red Colour, situated in the left hypochondriac region. It is variable in size and wreight, spongy and vascular in texture, and exceedingly friable. The external surface is convex, the internal slightly concave, indented along the middle line, and pierced by several large and irregular openings for the entrance THE SUPRA-RENAL CAPSULES. 527 ■ c c ■/■■■' ■ ' " ' and exit of vessels; this is the hilus lienis. The upper extremity is some- what larger than the lower, and rounded; the inferior is flattened ; the posterior border is obtuse, the anterior is sharp, and marked by several notches. The spleen is in relation by its external or, convex surface with the diaphragm, which separates it from the ninth, tenth, and eleventh ribs; by its concave surface, with the great end of the stomach, the extremity of the pancreas, the gastro-splenic omentum and its vessels, the left kidney and supra-renal capsule, and the left crus of the diaphragm ; by its upper end, with the diaphragm, and sometimes with the extremity of the left lobe of the liver; and, by its lower end, with the left extremity of the transverse arch of the colon. It is connected to the stomach by the gastro-splenic omentum, and by the vessels contained in that duplicature. A second spleen (lien succenturiatus) is sometimes found appended to one of the branches of the splenic artery, near the great end of the stomach ; when it exists, it is round and of small size, rarely larger than a hazel-nut. I have seen two, and even three, of these bodies. The spleen is invested by the peritoneum and by a tunica propria of yellow elastic tissue, which enables it to yield to the greater or less distension of its vessels. The elastic tunic forms sheaths for the vessels in their ramifications through the organ, and from these sheaths small fibrous bands are given off in all di- rections, which become attached to the internal surface of the elastic tunic, and constitute the areolar framework of the spleen. The substance occu- pying the interspaces of this tissue is soft, granular, and of a bright red colour; and frequently interspersed with small, white, soft corpuscles (Malpighian bodies). These corpuscles, according to the researches of Oesterlen and Mr. Simon, are aggregations of cyto-blasts enclosed in a kind of capsule of capillary vessels. There are, besides, separate cyto- blasts scattered through the red substance. Vessels and JYerves.—The Splenic artery is of very large size in propor- tion to the bulk of the spleen ; it is a division of the cceliac axis. The branches which enter the spleen are distributed to distinct sections of the organ, and anastomose very sparingly with each other. The veins by their numerous dilatations constitute the principal part of the bulk of the spleen; they pour their blood into the splenic vein, which is one of the two great formative trunks of the portal vein. The lymphatics are remarkable for their number and large size ; they terminate in the lumbar glands. The nerves are, the splenic plexus, derived from the solar plexus. THE SUPRA-RENAL CAPSULES. The supra-renal capsules are two small yellowish and flattened bodies surmounting the kidneys, and inclining inwards towards the vertebral column. The right is somewhat three-cornered in shape, the left semi- lunar ; they are connected to the kidneys by the common investing areolar tissue, and each capsule is marked on its anterior surface by a fissure which appears to divide it into two lobes. The right supra-renal capsule is closely adherent to the posterior and under surface of the liver, and the left lies in contact with the pancreas. Both capsules rest against the crura of the diaphragm on a level with the tenth dorsal vertebra, and, by their inner border, are in relation with the great splanchnic nerve and semilunar ganglion. They are larger in the foetus than in the adult, and appear to 528 THE KIDNEYS. perform some office connected with embryonic life. The anatomy of these organs in the foetus will be found in the succeeding chapter. In structure they are composed of two substances, cortical and medul- lary. The cortical substance is of a yellowish colour, and consists of straight parallel columns placed perpendicularly side by side. The me- dullary substance is generally of a dark brown colour, double the quantity of the yellow substance, soft and spongy in texture, and contains within its centre the trunk of a large vein, the vena supra-renalis. It is the large size of this vein that gives to the fresh supra-renal capsule the appearance of a central cavity: the dark-coloured pulpy or fluid contents of the cap- sule, at a certain period after death, are produced by softening of the me- dullary substance. Dr. Nagel* has shown, by his injections and micro- scopic examinations, that the appearance of columns in the cortical substance is caused by the direction of a plexus of capillary vessels. Of the numer- ous minute arteries, supplying the supra-renal capsule, he says, the greater number enter the cortical substance at every point of its surface, and, after proceeding for scarcely half a line, divide into a plexus of straight capil- lary vessels. Some few of the small arteries traverse the cortical layer, and give off, in the medullary substance, several branches which proceed in different directions, and re-enter the cortical layer to divide into a ca- pillary plexus in a similar manner with the first described. From the capillary plexus, composing the cortical layer, the blood is received hy numerous small veins which form a venous plexus in the medullary sub- stance, and terminate at acute angles in the large central vein. According to the more recent researches of Oesterlen and Mr. Simon, the appearance of columns is due to groups of small corpuscles or cyto- blasts associated with elementary granules and fat-cells collected together in the form of parallel cylinders or cones, each group being enclosed in a tube of delicate membrane (limitary membrane). The medullary sub- stance and intercolumnar spaces contain cyto-blasts uniformly scattered and interspersed with granules and fat-cells. Oesterlen found also, occa- sionally, in the medullary substance elongated spaces, without lining membrane, containing a thick greyish-white fluid. Vessels and JYerves.—The supra-renal arteries are derived from the aorta, from the renal, and from the phrenic arteries; they are remarkable for the innumerable minute twigs into which they divide previously to entering the capsule. The supra-renal vein collecting the blood from the medullary venous plexus, and receiving several branches which pierce the cortical layer, opens directly into the vena cava on the right side, and into the renal vein on the left. The Lymphatics are large and very numerous; they terminate in the lumbar glands. The nerves are derived from the renal and from the phrenic plexus. THE KIDNEYS. The kidneys, the secreting organs of the urine, are situated in the lum- bar regions, behind the peritoneum, and on each side of the vertebral column, which latter they approach by their upper extremities. Each kidney is between four and five inches in length, about two inches and a half in breadth, somewhat more than one inch in thickness, and weighs between three and five ounces. vThe kidneys are usually enclosed in a * Miiller's Archiv. 1836. STRUCTURE OF THE KIDNEYS. 529 quantity of fat; they rest on the diaphragm, on the anterior lamella of the transversalis muscle, which separates them from the quadratus lumborum, and on the psoas magnus. The right Iddney is somewhat lower than the left, from the position of the liver; it is in relation, by its anterior surface, with the liver and descending portion of the duodenum, which rest against it; and it is covered in by the ascending colon and by its flexure. The left kidney, higher than the right, is covered, in front, by the great end of the stomach, by the spleen, descending colon with its flexure, and by a portion of the small intestines. The anterior surface of the kidney is convex, while the posterior is flat; the superior extremity is in relation with the supra-renal capsule ; the convex border is turned outwards to- wards the parietes of the abdomen; the concave border looks inwards towards the vertebral column, and is excavated by a deep fissure, the hilus renalis, in wiiich are situated the vessels and nerves and pelvis of the kidney; the renal vein being the most anterior, next the renal artery, and lastly the pelvis. The kidney is dense and fragile in texture, and is invested by a proper fibrous capsule, which is easdy torn from its surface. When divided by a longitudinal incision, carried from the convex to the concave border, it is found to present in its interior two structures, an external or vascular (cortical), and an internal or tubular (medullary) substance. The tubular portion is formed of pale reddish-coloured conical masses, corresponding by their bases with the vascular structure, and by their apices with the hilus of the organ ; these bodies are named cones (pyramids of Malpighi), and are from eight to fifteen in number. The vascular portion is com- posed of blood-vessels and of the plexiform convolutions of uriniferous tubuli, and not only constitutes the surface of the kidney, but dips be- tween the cones and surrounds them nearly to their apices. The cones or pyramids of the tubular portion of the kidney are com- • posed of minute straight tubuli uriniferi, of about the diameter of a fine hair. The tubuli commence at the apices of the cones, and pursue a pa- rallel course towards the periphery of the organ, bifurcating from point to point, and separated only by minute straight blood-vessels, and a small quantity of parenchymatous substance. At the bases of the pyramids the tubuli collect into smaller conical fasciculi, which are prolonged into the substance of the cortical portion of the kidney, and have interposed be- tween them processes of the vascular structure. In the smaller pyramids the fasciculi separate into their component tubules, which, after a course marked by " tortuosities, plexuses, convolutions, and dilatations," ter- minate, according to Mr. Bowman,f in small round bodies, the corpora • A section of the kidney, surmounted by the supra-renal capsule ; the swellings in the surface mark the original constitution of the organ of distinct lobes. 1. The supra renal capsule. 2. The vascular portion of the kidney. 3, 3. Its tubular portion, con- sisting of cones. 4, 4. Two of the papilla? projecting into their corresponding calices. 5. 5, 5. The three infundibula; the middle 5 is situated in the mouth of a calyx. tJ The pelvis. 7. The ureter. f On ihe Structure and Use of the Malpighian Bodies of the Kidney. Philosophica' Transactions, 1842. 45 21 530 STRUCTURE OF THE KIDNEYS. Malpighiana, or, according to Krause and the recent investigations of Mr. Toynbee,* by anastomoses and caecal extremities. The average . lowing analytical* results: one hundred parts of the fluid contained six teen parts of solid matter, which consisted of, Incipient fibrine, Albumen, Mucus, and muco-extractive matter, Muriate and phosphate of potass Phosphate of soda, Phosphoric acid, a trace. According to the researches of Mr. Simonf and Oesterlen the thymus is composed of polygonal and mutually flattened membranous cells, measur- ing from half a line to two lines in diameter and arranged in conical masses around a central cavity. Each cell is surrounded by a capillary plexus and connected to neighbouring cells by areolar tissue intermingled with elastic fibres. The corpuscles found in the fluid of the thymus are dotted nuclei measuring 353^ of an inch in diameter; and are subject to conver- sion into nucleated cells and fat-cells. The Arteries of the thymus gland are derived from the internal mam- mary, and from the superior and inferior thyroid. The Vdns terminate in the left vena innominata, and some small branches in the thyroid veins. The JYerves are very minute, and are derived chiefly, through the in- ternal mammary plexus, from the superior thoracic ganglion of the sympa- thetic. Sir Astley Cooper has also seen a branch from the junction of the pneumogastric and sympathetic pass to the side of the gland. The Lymphatics terminate in the general union of the lymphatic vessels at the junction of the internal jugular and subclavian veins. Sir Astley Cooper has injected them only once in the human foetus, but in the calf he finds two large lymphatic ducts, wiiich commence in the upper extre- mities of the glands, and pass downwards, to terminate at the junction of the jugular and subclavian vein at each side. These vessels he considers to be the "absorbent ducts of the glands; 'thymic ducts;' they are the carriers of the fluid from the thymus into the veins." Sir Astley Cooper concludes his anatomical description of this gland with the following observations:— "As the thymus secretes all the parts of the blood, viz. albumen, fibrine, and particles, is it not probable that the gland is designed to prepare a fluid well fitted for the foetal growth and nourishment from the blood of the mother, before the birth of the foetus, and, consequently, before chyle is formed from food ?—and this process continues for a short time after birth, the quantity of fluid secreted from the thymus gradually declining as 4>at of chylification becomes perfectly established." FCETAL LUNGS. The Lungs, previously to the act of inspiration, are dense and solid in structure, and of a deep red colour. Their specific gravity is greater than water, in which they sink to the bottom ; wiiereas lung which has respired will float upon that fluid. The specific gravity is, however, no test of the * This analysis was conducted by Dr. Dowler of Richmond. ■j- "A Physiological Essay on the Thymus Gland," 4to. 1S4G. VISCERA OF THE ABDOMEN. 559 real weight of the lung, the respired lung being actually heavier than the foetal. Thus the weight of the foetal lung, at about the middle period of uterine life, is to the weight of the body as 1 to 60.* But, after respira- tion, the relative weight of the lung to the entire body is as 1 to 30. FCETAL HEART. The Heart of the foetus is large in proportion to the size of the body; it is also developed very early, representing at first a simple vessel, and un- dergoing various degrees of complication until it arrives at the compound character which it presents after birth. The two ventricles form, at one period, a single cavity, which is afterwards divided into two by the septum ventriculorum. The two auricles communicate up to the moment of birth, the septum being incomplete, and leaving a large opening between them, the foramen ovale (foramen of Botalf). The Ductus arteriosus is another peculiarity of the foetus connected with the heart; it is a communication between the pulmonary artery and the aorta. It degenerates into a fibrous cord after birth, from the double cause, of a diversion in the current of the blood towards the lungs, and from the pressure of the left bronchus, caused by its distension with air. VISCERA OF THE ABDOMEN. At an early period of uterine life, and sometimes at the period of birth, as I have twice observed in the imperfectly developed foetus, two minute fibrous threads may be seen passing from the umbilicus to the mesentery. These are the remains of the omphalo-mesenteric vessels. The Omphalo-mesenteric are the first developed vessels of the germ: . they ramify upon the vesicula umbilicalis, or yolk-bag, and supply the newly formed alimentary canal of the embryo. From them, as from a centre, the general circulating system is produced. After the establish- ment of the placental circulation they cease to carry blood, and dwindle to the size of mere threads, which maybe easily demonstrated in the early periods of uterine life; but are completely removed, excepting under pe- culiar circumstances, at a later period. The Stomach is of small size, and the great extremity but little deve- loped. It is also more vertical in direction the earlier it is examined, ? position that would seem due to the enormous magnitude of the liver, anc particularly of its left lobe. The Appendix vermiformis ced is long and of large size, and is con- tinued directly from the central part of the cul-de-sac of the caecum, of which it appears to be a constricted continuation. This is the character of the appendix cseci in the higher quadrumana. The large intestines are filled wkh a dark green viscous secretion, called meconium (m-^xwv, poppy), from its resemblance to the inspissated juice of the poppy. The Pancreas is comparatively larger in the foetus than in the adult. The Spleen is comparatively smaller in the foetus than in the adult. • Cruveilhier, Anatomie Descriptive, vol. ii. p. 621. ■j- Leonard Botal, of Piedmont, was the first of the moderns who gave an account of this opening in a work published in 1565. His description is very imperfect. The foramen was well known to Galen. 560 FCETAL LIVER—TESTES. FCETAL LIVER. The Liver is the first formed organ in the embryo. It is developed from the alimentary canal, and at about the third week, fills the whole abdomen, and is one-half the weight of the entire embryo. At the fourth month the liver is of immense size in proportion to the bulk of the foetus. At birth it is of very large size, and occupies the whole upper part of the abdomen. The left lobe is as large as the right, and the falciform liga- ment corresponds with the middle line of the body. The liver diminishes rapidly after birth, probably from obliteration of the umbilical vein. KIDNEYS AND SUPRA-RENAL CAPSULES. The Kidneys present a lobulated appearance in the foetus, which is their permanent type amongst some animals, as the bear, the otter, and cetacea. The Supra-renal capsules are organs which appear, from their early, and considerable development, to belong especially to the economy of the fcetus. They are distinctly formed at the second month of embryonic life, and are greater in size and weight than the kidneys. At the third or fourth month, they are equalled in bulk by the kidneys; and at birth, they are about one-third less than those organs. VISCERA OF THE PELVIS. The Bladder in the fcetus is long and conical, and is situated altogether above the upper border of the ossa pubis, which are as yet small and un- developed. It is, indeed, an abdominal viscus, and is connected supe- riorly with a fibrous cord, called the urachus, of which it appears to be an expansion. The Urachus is continued upwards to the umbilicus, and becomes con- nected with the umbilical cord. In animals it is a pervious duct, and is continuous with one of the membranes of the embryo, the allantois. It has been found pervious in the human foetus, and the urine has been passed through the umbilicus. Calculous concretions have also been found in its course. The Uterus, in the early periods of embryonic existence, appears bifid, from the large size of the Fallopian tubes, and the small development of the body of the organ. At the end of the fourth month, the body assumes a larger bulk, and the bifid appearance is lost. The cervix uteri in the foetus is larger than the body of the organ. The Ovaries are situated, like the testicles, in the lumbar region, neai the kidneys, and descend from thence, gradually, into the pelvis. TESTES. The Testicles in the embryo are situated in the lumbar regions, imme- diately in front of and somewhat below the kidneys. They have, con nected with them inferiorly, a peculiar structure, which assists in their descent, and is called the gubernaculum testis. The Gubernaculum is a soft and conical cord composed of areolar tissue containing in its areolae a gelatiniform fluid. In the abdomen it lies in front of the psoas muscle, and passes along the spermatic canal, which il DESCENT OF THE TESTIS. 561 ?erves to distend for the passage of the testis. It is attached by its supe- rior and larger extremity to the lower end of the testis and epididymis, and by the inferior extremity to the bottom of the scrotum. The gubernaculum is surrounded by a thin layer of muscular fibres, the cremaster, which pass upwards upon this body to be attached to the testis. Inferiorly, the mus- cular fibres divide into three processes, which, according to Mr. Curling,* are thus attached: " The external and broadest is connected to Poupart's ligament in the inguinal canal; the middle forms a lengthened band, which escapes at the external abdominal ring, and descends to the bottom of the scrotum, where it joins the dartos; the internal passes in the direc- tion inwards, and has a firm attachment to the os pubis and sheath of the rectus muscle. Besides these, a number of muscular fibres are reflected from the internal oblique on the front of the gubernaculum." The Descent of the testicle is gradual and progressive. Between the fifth and sixth months it has reached the lower part of the psoas muscle, and during the seventh it makes its way through the spermatic canal, and descends into the scrotum. While situated in the lumbar region, the testis and gubernaculum are placed behind the peritoneum, by which they are invested upon their, an- terior surface and sides. As they descend, the investing peritoneum is carried downwards with the testis into the scrotum, forming a lengthened Fig. 248.f Fig. 2494 pouch, which by its upper extremity opens into the cavity of the perito- neum. The upper part of this pouch, being compressed by the spermatic canal, is gradually obliterated, the obliteration extending downwards along the spermatic cord nearly to the testis. That portion of the perito- neum which immediately surrounds the testis is, by the above process, cut off from its continuity with the peritoneum, and is termed the tunica * See an excellent paper " On the Structure of the Gubernaculum," &c, by Mr. Curl- ing, Lecturer on Morbid Anatomy in the London Hospital, in the Lancet, vol. ii. 1840-41, p. 70. f A diagram illustrating the descent of the testis. 1. The testis. 2. The epididymis. 3, 3. The peritoneum. 4. The pouch formed around the testis by the peritoneum, the future cavity of the tunica vaginalis. 5. The pubic portion of the cremaster attached to the lower part of the testis. 6. The portion of the cremaster attached to Poupart's liga- ment. The mode of eversion of the cremaster is shown by these lines. 7. The guber- naculum, attached to the bottom of the scrotum, and becoming shortened by the con- traction of the muscular fibres which surround it. 8, 8. The cavity of the scrotum. * In this figure the testis has completed its descent. The gubernaculum is shortened to its utmost, and the cremaster completely everted. The pouch of peritoneum above the testis is compressed so as to form a tubular canal; 1. A dotted line marks the point at which the tunica vaginalis will terminate superiorly; and the number 2 its cavity 3. The peritoneal cavity. 2l 562 DESCENT OF THE TESTIS. vaginalis ; and as this membrane must be obviously a shut sac, one por- tion of it investing the testis, and the other being reflected so as to form a loose bag around it, its two portions have received the appellations of tunica vaginalis propria, and tunica vaginalis reflexa. The descent of the testis is effected by means of the traction of the muscle of the gubernaculum (cremaster). " The fibres," writes Mr. Curl- ing,* " proceeding from Poupart's ligament and the obliquus internus, tend to guide the gland into the inguinal canal; those attached to the os pubis, to draw it below the abdominal ring; and the process descending to the scrotum, to direct it to its final destination." During the descent, " the muscie of the testis is gradually everted, until, when the transition is completed, it forms a muscular envelope external to the process of peri- toneum, which surrounds the gland and the front of the cord." " The mass composing the central part of the gubernaculum, which is so soft, lax, and yielding as in every way to facilitate these changes, becomes gra- dually diffused, and, after the arrival of the testicle in the scrotum, con- tributes to form the loose cellular tissue which afterwards exists so abun- dantly in this part." The attachment of the gubernaculum to the bottom of the scrotum is indicated throughout life by distinct traces. • Loc. cit. v. INDEX. A. Abdomen, 496 Abdominal regions, 496 Abdominal ring, 212, 266 Abductor oculi, 177 Acetabulum, 116 Acini, 519 Adductor oculi, 177 Adipose tissue, 136 Air-celts. 494 Albino, 452 Alcock, Dr., researches of, 396 Alimentary canal, 501 Allantois, 560 Amphi-arthrosis, 130 Ampulla, 459 Amygdalae, 503 cerebri, 380 Andersch, notice of, 404 Annulus ovalis, 478 Antihelix, 456 Antitragus, 456 Antrum of Highmore, 74 pylori, 506 Anus, 509-514 Aorta, abdominal, 280 arch, 279 ascending, 279 thoracic, 280 Aortic sinuses, 278 Aponeurosis, 168 Apophysis, 48 Apparatus ligamentosus colli, 141 Appendices epiploicae; 501 Appendix vermiformis, 507 Aqua Iabyrinthi, 463 Aqueductus cochlea?, 463 vestibuli, 462 Aqueduct of Sylvius, 379 Aqueous humour, 451 Arachnoid membrane, 370 Arantius, notice of, 480 Arbor vitae, 382 uterina, 547 Arch, femoral, 273 palmar, superficial, 308 Arciform fibres, 386 Areola, 552 Areolar tissue, 136 Arnold, Frederick, researches, 435 Arteries. General anatomy, 275 structure, 277 anastomotica, femor. 326 brachial, 304 Arteries—continued. angular, 285 aorta, 278 articulares genu, 327 auricula anterior. 268 posterior, 287 axillary, 300 basilar, 296 brachial, 303 bronchial, 308 bulbosi, 320 calcanean, 332 carotid, common, 282 external, 283 internal, 291 carpal ulnar, 308 radial, 306 cavernosi, 320 centralis retina, 293, 452 cerebellar inferior, 297 superior, 297 cerebral, 293,. 294 cervicalis anterior, 299 posterior, 299 choroidean, 294 ciliary, 293 circumflex anterior, 302 external, 325 circumflex ilii, 322, 324 internal, 326 posterior, 302 coccygeal, 318 cceliac, 310 colic, 314, 315 comes nervi ischiatici, 319 phrenici, 300 communicans cerebri, 294 pedis, 330 coronaria cordis, 281 dextra, 281 labii, 286 sinistra, 281 ventriculi, 310 corporis bulbosi, 320 cavernosi, 320 cremasteric, 322 cystic, 311 dental, 2SJ? digitales mantis, 308 pedis, 333 dorsales pollicis, 306 dorsalis linguae, 285 carpi, 306 hallucis, 330 nasi, 293 pedis, 333 (563) 561 INDEX. Arteries—-continued. penis, 320 scapulae, 302 emulgent, 315 epigastric, 322 superficial, 325 ethmoidal, 293 facial, 285 femoral, 323 frontal, 293 gastric, 310 gastro-duodenalis 311 epiploica dextra, 311 sinistra, 311 gluteal, 321 inferior, 318 haemorrhoidal, external, 319 middle, 318 superior, 315 inferior, 318 hepatic, 310 ileo-colic, 313 iliac, common, 316 external, 321 internal, 317 ileo-lumbar, 320 infra-orbital, 290 innominata, 281 intercostal, 309 anterior, 300 superior, 299 inter-osseous, 307, 308 intestini tenuis, 312 ischiatic, 318 labial, 286 lachrymal, 292 laryngeal, 285 lateralis nasi, 286 lingual, 285 lumbar, 315 malleolar, 329 mammary, internal, 299 masseteric, 286 mastoid, 287 maxillary, internal, 288 mediastinal, 300 meningea, anterior, 292 inferior, 287 media, 290 parva, 290 posterior, 297 mesenteric, 312 inferior, 315 metacarpal, 306 metatarsal, 330 musculo-phrenic, 300 nasal, 293 obturator, 320 occipital, 287 oesophageal, 308 ophthalmic, 292 orbitar, 288 palatine, inferior, 286 posterior, 290 palpebral, 293 pancreatica magna, 311 ' pancreaticse parvae, 311 pancreatico-duodenalis, 311 parotidean, 287 perforantes, femoral, 326 palmares, 306 plantare6, 332 pericardiac, 300 perineal, superficial, 319 Arteries—continued. peroneal, 331 pharyngea ascendens, 287 phrenic, 309 plantar, external, 332 internal, 332 popliteal, 326 princeps cervicis, 287 pollicis, 306 profunda cervicis, 299 femoris, 325 inferior, 304 superior, 303 pterygoid, 286 pterygo-palatine, 290 pudic, external, 325 internal, 318 pulmonary, 334 pyloric, 311 radial, 304 radialis indicis, 306 ranine, 285 recurrens interosseous, 308 radialis, 305 tibialis, 329 ulnaris, 307 renal, 315 sacra media, 316 lateralis, 321 scapular, posterior, 299 sigmoid, 315 spermatic, 314 spheno-palatine, 290 spinal, 297 splenic, 311 stylo-mastoid, 287 subclavian, 294 sublingual, 285 submaxillary, 286 submental, 286 subscapular, 302 superficialis cervicis, 299 volae, 306 supra-orbital, 293 supra-renal, 315 scapular, 298 sural, 328 tarsea, 330 temporal, 288 temporales profundae, 290 thoracic, 302 thyroidea inferior, 298 media, 282 superior, 284 tibialis antica, 328 postica, 330 transversalis colli, 299 faciei, 287 humeri, 298 perinei, 320 tympanic, 289 ulnar, 306 umbilical, 317 uterine, 320 vaginal, 320 vasa brevia, 311 intestini tenuis, 312 vertebral, 296 vesical, 318 Vidian, 291 Arthrodia, 130 Articulations, 137 Arytenoid cartilages, 486 Arytenoid glands, 491 INDEX. 566 Auricles of the heart, 477, 481 Auriculo-ventricular openings, 478, 481 B. Barry, Dr., researches of, 550 Base of the brain, 382 Bauhini, valvula, 510 Bell, Sir C, researches of, 366 Berzelius, analysis of bone, 43 Biliary ducts, 525 Bladder, 532 Bones, chemical composition, 43 development, 46 general anatomy, 43 structure, 44 astragalus, 124 atlas, 51 axis, 52 calcis, 124 carpus, 109 clavicula, 103 coccyx, 58 costae, 102 cuboides, 126 cuneiforme carpi, 110 externum tarsi, 125 internum, 126 medium, 128 ethmoides, 72 femur, 119 fibula, 122 frontale, 62 humerus, 105 hyoides, 99 ilium, 114 innominatum, 114 ischium, 115 lachrymale, 77 magnum, 111 malare, 77 maxillare superius, 74 maxillare inferius, 81 metacarpus, 112 metatarsus, 127 nasi, 74 naviculare, 125 occipitale, 59 palati, 77 parietaie, 61 patella, 121 phalanges manus, 113 pedis, 128 pisiforme, 110 pubis, 116 radius, 107 sacrum, 56 scaphoides carpi, 109 tarsi, 125 scapula, 103 semilunare, 109 sesamoidea manus, 129 pedis, 129 sphenoides, 69 sternum, 100 tarsus, 124 temporal, 64 tibia, 121 trapezoides, 111 trapezium, 110 triquetra, 84 lurbinatum inferius, 80 superius, 73 ulna, 106 48 Bones—continued. unciforme, 112 unguis, 77 vertebra prominens, 52 vertebra dentata, 52 vertebrae, cervical, 50 dorsal, 53 lumbar, 53 vomer, 80 Wormiana, 84 Botal, foramen of, 559 notice of, 559 Bowman, Mr., researches of, 170, 529 Brain, 367 Bronchi, 494 Bronchial cells, 494 tubes, 494 Bronchocele, 392 Brunn, Von, notice of, 512 Brunner's glands, 512 Bulb, corpus spongiosum, 537 Bulbi fornicis, 384 Bulbous part of the urethra, 539 Bulbus olfactorius, 394 Bursa? mucosae, 137 C. Caecum, 507 Calamus scriptorius, 380 Calyces, 530 Camper's ligament, 269 Canal of Fontana, 447 Petit, 452 Sylvius, 379 Canals of Havers, 44 Canthi, 453 Capillaries, 276 Capitula Santorini, 486 Capsule of Glisson, 521 Capsules supra-renal, 527 Caput gallinaginis, 539 Cardia, 505 Carpus, 109 Cartilage, 46, 132 Cartilages. inter-articular of the clavicle, 150 inter-articular of the jaw, 144 inter-articular of the wrist, 155 semilunar, 161 Cartitaginification, 132 Caruncula lachrymalis, 454 mammillaris, 384 Carunculae myrtiformes, 551 Casserian ganglion, 391 Cauda equina, 390 Cava, vena, 346 Cementum, 94 Centrum ovale majus, 373 minus, 374 Cerebellum, 381 Cerebro-spinal axis, 367 Cerebrum, 372 Ceruminous follicles, 457 Cervical ganglia, 437 Chambers of the eye, 451 Cheeks, 502 Chiasma nerv. opt. 394 Chorda tympani, 402 Chorda? longitudinales, 390 tendineae, 479, 482 vocales, 488 Willisii, 368 Choroid membrane, 448 566 INDEX. Choroid plexus, 375 Ciliae, 453 Ciliary canal, 448 ligament, 448 processes, 448 Circle of Willis, 298 Circulation, adult, 276 foetal, 585 Circulus tonsillaris, 287 Clitoris, 551 Clivus Blumenbachii, 69 Cochlea, 463 Cock, Mr., researches of, 407 Cceliac axis, 310 Colon, 508 Columna nasi, 443 Columnae carneae, 479, 482 Commissures, 362, 378 great, 373 Conarium, 379 Concha, 456 Congestion of the liver, 523 Coni renales, 529 vasculosi, 543 Conjunctiva, 454 Converging fibres, 388 Cooper, Sir Astley, researches of, 55 Corium, 469 Cornea, 446 Cornicula laryngis, 486 Cornu Ammonis,' 376 Cornua of the ventricles, 373, 375 Corona glandis, 536 Coronary valve, 478 Corpora albicantia, 384 Arantii, 480 cavernosa, 536 geniculata, 378 Malpighiana, 530 mammillaria, 384 olivaria, 385 pisiformia, 384 pyramidalia, 385 quadrigemina, 379 restiformia, 386 striata, 374 Corpus callosum, 37 cavernosum, 536 dentatum, 382 fimbriatum, 376 geniculatum externum, 378 internum, 378 Highmorianum, 542 luteum, 550 psalloides, 398 rhomboideum, 382 spongiosum, 537 striatum, 374 Costal cartilages, 102 Cotunnius, notice of, 463 Cowper's glands, 540 Cranial nerves, 392 Cribriform fascia, 272 Cricoid cartilage, 486 Crico-thyroid membrane, 487 Crura cerebelli, 382 cerebri, 378 penis, 536 Crural canal, 272 ring, 273 Crystalline lens, 451 Cuneiform cartilages, 486 Cupola, 461 Curling, Mr., researches of, 561, 562 Cuticle, 470 Cutis, 468 Cystic duct, 525 Cyto-blast, 470 D. Dartos, 540 Davy, Dr., researches of, 296 Derbyshire neck, 392 Dermis, 468 Detrusor urinae, 533 Diaphragm, 217 Diaphysis, 48 Diarthrosis, 130 Digital cavity, 375 Diverging fibres, 386 Dorsi-spinal veins, 348 Ductus ad nasum, 456 arteriosus, 553 comm. choledochus, 525 cysticus, 525 ejaculatorius, 537 hepaticus, 525 lymphaticus dexter, 360 pancreaticus, 526 prostaticus, 535 thoracicus, 360 venosus, 553 Duodenum, 506 Dura mater, 368 E. Ear, 456 Ejaculatory duct, 537 Elastic tissue, 135 Enamel, 94 Enarthrosis, 131 Encephalon, 367 Endolymph, 462 Ensiform cartilage, 100 Entozoon follicuTorum, 474 Epidermis, 470 Epididymis, 543 Epigastric region, 496 Epiglottic gland, 491 Epiglottis, 486 Epiglotto-hyoidean ligament, 488 Epiphysis, 48 Epithelium, 511 Erectile tissue, 537 Eustachian tube, 460 valve, 478 Eustachius, notice of, 478 Eye, 445 brows, 453 globe, 445 lashes, 453 lids, 453 F. Falciform process, 273 Fallopian tubes, 549 Fallopius, notice of, 549 Falx cerebelli, 369 cerebri, 369 Fascia. general anatomy of, 263 cervical, deep, 264 superficial, 264 cribriform, 272 dentata, 376 INDEX. 5C7 Fascia—continued. iliaca, 268 inter-columnar, 212 lata, 272 lumbar, 215 obturator, 269 palmar, 271 pelvica, 268 perineal, 269 plantar, 274 propria, 274 recto-vesical, 269 spermatica, 212 temporal, 264 thoracic, 265 transversalis, 266 Fasciculi innominati, 387 siliquae, 388 teretes, 389 Fauces, 502 Femoral arch, 273 canal, 273 hernia, 273 ring, 273 Fenestra ovalis, 460 rotunda, 460 Fibres of the heart, 483 Fibro-cartilage, 133 inter-articular of the clavicle, jaw, 144 knee, 161 wrist, 155 cellular tissue, 136 Fibrous tissue, 135 V Filum terminate, 390 Fimbriae, Fallopianae, 549 Fissure of Bichat, 361 Sylvius, 372 Fissures of the liver, 517 Flocculus, 381 Foetal circulation, 553 Fcetus, anatomy of, 552 Follicles of Lieberkuhn, 543 Fontana, notice of, 449 Foramen of Botal, 478 caecum, 467 commune anterius, 381 posterius, 381 Monro, of, 378 ovale, 553 saphenum, 273 Soemmering, of, 449 Winslow, of, 500 Foramina Thebesii, 477 Fornix, 377 Fossa innominata, 456 navicularis urethrae, 537 pudendi, 551 ovalis, 478 scaphoides, 456 Fourchette, 550 Fraena epiglottidis, 467, 488 Fraenulum labiorum, 550 veli medull., 380 Fraenum labii, 468 linguae, 467 praeputii, 536 Funiculi siliquae, 386 graciles, 386 6. Galea capitis, 174 Galen, 275 Gall-bladder, 525 Ganglia, cervical, 437 of increase, 361 lumbar, 441 sacral, 442 semilunar, 441 structure of, 361 thoracic, 440 Ganglion of Andersch, 404 Arnold's, 436 azygos, 442 cardiac, 440 carotid, 439 Casserian, 396 ciliary, 433 Cloquet's, 435 impar, 442 jugular, 403 lenticular, 433 Meckel's, 435 naso-palatine, 435 otic, 436 petrous, 403 plexiforme, 404 Ribes, of, 433 spheno-palatine, 435 submaxillary, 436 thyroid, 438 vertebral, 438 Gimbernat's ligament, 216 Ginglymus, 130 Gland, epiglottic, 491 lachrymal, 455 parotid, 503 pineal, 379 pituitary, 384 prostate, 534 thymus, 556 thyroid, 492 Glands, aggregate, 513 arytenoid, 491 Brunner's, 512 concatenated, 354 Cowper's, 540 duodenal, 512 gastric, 512 inguinal, 355 lachrymal, 455 Lieberkuhn's, 513 lymphatic, 358 mammary, 583 mesenteric, 361 Meibomian, 454 oesophageal, 512 Pacchionian, 369 Peyer's, 513 pharyngeal, 512 salivary, 503 sebaceous, 474 solitary, 513 sublingual, 504 submaxillary, 503 sudoriparous, 474 tracheal, 492 Glandulae odoriferae, 5 irt> Pacchioni, 369 Tysoni, 536 Glans clitoridis, 551 penis, 536 Glisson, notice of, 500 Glisson's capsule, 519 Globus major-epididymis, 54J minor epididymis, 543 Glottis, 490 5G8 Goodsir, Mr., researches of, 95 Goitre, 392 Gomphosis, 130 Graafian vesicles, 550 Grainger, Mr., researches of, 367 Gubernaculum testis, 560 Gums, 502 Guthrie, Mr., researches of, 534 Guthrie's muscle, 220 Gyrus fornicatus, 376 H. Hair, 473 Hall, Dr. Marshall, researches of, 367 Harmonia, 130 Haversian canals, 44 Heart, 475 Helicine arteries, 537 Helico-trema, 464 Helix, 456 Hepatic duct, 525 Hernia, congenital, 267 diaphragmatic, 217 direct, 268 encysted, 267 femoral, 273 infantilis, 267 , inguinal, 266 scrotal, 268 Highmore, notice of, 542 Hilton's muscle, 484 Hilus lienis, 557 renalis, 529 Hippocampus major, 376 minor, 376 Horner's muscle, 176 Horner, W. E., observations of, 514 Houston, Mr., researches of, 511 Humours of the eye, 451 Hyaloid membrane, 451 Hymen, 551 Hyoid bone, 99 Hypochondriac regions, 496 Hypogastric region, 496 Hypophysis cerebri, 384 I. Ileo-caecal valve, 510 Ileum, 507 Iliac regions, 496 Incus, 458 Infundibula, 530 Infundibulum, 383 Inguinal region, 496 Inter-articular cartilages of the clavicle, jaw, 144 • wrist, 155 Inter-columnar fibres, 212 Inter-vertebral substance, 138 Intestinal canal, 501 Intumescentia gangliformis, 401 Iris, 448 Isthmus of the fauces, 502 Iter ad infundibulum, 379 a tertio ad quartum ventriculum, 379 J. Jacob'8 membrane, 450 Jejunum, 507 Joint, ankle, 165 elbow, 15? INDEX. Joint, hip, 158 lower jav, 14S knee, 160 shoulder, 152 wrist, 155 Jones, Mr., researches of, 464 K. Kidneys, 528 Kiernan, Mr., researches of, 520 King, Mr. T. W., researches of, 479 Krause, researches of, 222 L. Labia majora, 550 minora, 550 Labyrinth, 461 Lachrymal canals, 455 gland, 455 papillae, 455 puncta, 455 sac, 456 tubercles, 453 Lacteals, 358 Lacunae, 540 Lacus lachrymalis, 455 Lamina cinerea, 382 cribrosa, 446 spiralis, 464 Laqueus, 388 Laryngotomy, 487 Larynx, 485 Lateral ventricles, 378 Lauth, researches of, 542 Lee, Dr., researches of, 548 Lens, 451 Lenticular ganglion, 433 Lieberkuhn's follicles, 513 Lien succenturiatus, 528 Ligament, 135 Lisaments, 129 acromio-clavicular, 151 alar, 141, 162 ankle, of the, 164 annular, of the ankle, 274 radius, 153 wrist, anterior, 155 posterior, 271 arcuatum externum, 217 internum, 217 atlo-axoid, 141 bladder, of, 532 breve plantae, 166 calcaneo-astragaloid, 165 cuboid, 165 scaphoid, 166 capsular of the hip, 158 jaw, 143 rib, 145 shoulder, 152 thumb, 157 carpal, 156 carpo-metacarpal, 156 common anterior, 138 posterior, 138 conoid, 151 coracoid, 151 coraco-acromiaLj.51 clavicular**^! humeral, 152 coronary, 154 of the knee, 161 INDEX. 553 Liqaments—continued. costo-clavicular, 150" sternal, 145 transverse, 145 vertebral, 144 xiphoid, 146 cotyloid, 159 crico-thyroidean, 487 crucial, 161 cruciform, 142 dentatum, 382 deltoid, 165 elbow, of the, 152 epiglotto-hyoidean, 488 glenoid, 152 hip joint, of the, 158 hyo-epiglottic, 487 ilio-femoral, 159 inter-articular, of ribs, 145 inter-clavicular, 150 inter-osseous, 163, 166 calcaneo-astragal., 166 peroneo-tibial, 163 radio-ulnar, 153 inter-spinous, 139 inter-transverse, 140 inter-vertebral, 138 knee, of the, 160 lateral of the ankle, 165 elbow, 153 jaw, 143 knee, 160 phalanges, foot, 168 phalanges, hand, 157 wrist, 155 liver, of the, 516 longum plantae, 166 lumbo-iliac, 146 lumbo-sacral, 146 metacarpo-phalangeal, 157 metatarsal-phalangeal, 167 mucosum, 162 nuchae, 199 oblique, 154 obturator, 149 occipito-atloid, 140 axoid, 141 odontoid, 141 orbicular, 154 palpebral, 453 patellae, 160 peroneo-tibial, 163 phalanges of the foot, 167 of the hand, 157 plantar, long, 166 plantar, short, 166 posticum Winslowii, 160 pterygo-maxillary, 142 pubic, 149 radio-ulnar, 153 rhomboid, 150 rotundum, hepatis, 516 sacro-coccygean, 148 6acro-iliac, 147 sacro-ischiatic, anterior, 147 posterior, 148 stellate, 144 sternal, 145, 146 sterno-clavicular, 149 stylo-maxillary, 265. sub-flava, 139 ^fc sub-pubic, 149 supra-spinous, 139 euspensorium hepatis, 516 48* Ligaments—continued. suspensorium penis, 536 tarsal, 165 tarso-metatarsal, 167 teres, 159 thyro-arytenoid, 487 thyro-hyoidean, 487 tibio-fibular, 163 transverse, 164 of the acetabulum, 159 of the ankle, 164 of the atlas, 141 of the knee, 159 of the metacarpus, 157 of the metatarsus, 167 of the scapula, 151 of tO semilunar cartilages, 161 trapezoid, 151 tympanum, of the, 468 umbilical, 532 wrist, of the, 155 Zinn, of, 177 Ligamentum nucha?, 199 Limbus luteus, 449 Linea alba, 212 Linea? semi-lunares, 212 transversae, 212, 373 Linguetta laminosa, 380 Lips, 502 Liquor Cotunnii, 465 Morgagni, 451 Scarpa, of, 466 Liver, 515 Lobules of the liver, 519 Lobuli testis, 542 Lobulus auris, 456 pneumogastricus, 381 Lobus caudatus, 518 , quadratus, 518 Spigelii, 518 Locus niger, 383 perforatus, 383 Lower, notice of, 478 Lumbar fascia, 215 regions, 496 Lungs, 492 Lunula, 472 Lymphatic glands and vessels, 351 axillary, 354 bronchial, 357 cardiac, 358 cervical, 354 head and neck, 353 heart, 357 iliac, 357 inguinal, 355 intestines, 358, 359 kidney, 359 lacteals, 358 liver, 358 lower extremity, 355 lungs, 357 mediastinal, 356 mesenteric, 358 pelvic viscera, 359 popliteal, 355 spleen, 358 stomach, 358 testicle, 359 trunk, 356 upper extremity, 354 viscera, 357 Lyra, 377 570 INDEX. M. Malleus, 458 Malpighian bodies, 528, 530 Mammae, 551 Mammary gland, 552 Mastoid cells, 460 Matrix, 546 Maxillo-pharyngeal space, 192 Mayo, Mr., researches of, 395 Meatus, auditorius, 457 urinarius, female, 545 male, 536 Meatuses of the nares, 444 Meckel's ganglion, 435 Meconium, 559 Mediastinum, 496 testis, 542 Medulla of bones, 44 innominata, 383 oblongata, 385 Meibomian glands, 454 Meibomius, notice of, 454 Membrana dentata, 390 nictitans, 455 pigmenti, 448 pupillaris, 555 sacciformis, 153 tympani, 458 Membrane, choroid, 448 hyaloid, 451 Jacob's, 450 of the ventricles, 380 Membranous urethra, 539 Meniscus, 133 Mesenteric glands, 358 Mesentery, 498 Meso-colon, 498 Meso-rectum, 499 Metacarpus, 112 Metatarsus, 127 Mitral valves, 482 Modiolus, 463 Mons Veneris, 550 Monticulus cerebelli, 382 Morgagni, notice of, 451 Morsus diaboli, 549 Motor tract, 391 Mouth, 502 Mucous membrane, structure, 511 M tiller, researches of, 45 Muscles, 168 general anatomy of, 168 development of, 172 structure, 169 abductor min. digiti, 240 abduc. min. dig. pedis, 260 indicis, 241 oculi, 177 pollicis, 238 pedis, 260 accelerator urinae, 220 accessorius, 261 adductor brevis, 250 longus, 250 magnus, 250 min. digiti, 260 oculi, 177 pollicis, 239 pedis, 261 anconeus, 236 anterior auris, 185 anti-tragicus, 45~ arytenoideus, 489 Muscles—continued. aryteno-epiglot. inf.. 489 superior, 489 attollens aurem, 184 oculum, 177 attrahens aurem, 185 auricularus, 236 azygos uvulae, 195 basio-glossus, 191 biceps flexor cruris, 251 cubiti, 229 biventer cervicis, 204 brachialis anticus, 230 buccinator, 183 bulbo-cavernosus, 220 cerato-glossus, 191 cervicalis ascendens, 204 circumflexus palati, 195 coccygeus, 222 complexus, 204 compressor nasi, 179 urethra?, 220 constrictor inferior, 192 isth. faucium, 192, 195 medius, 193 pharyngis, 192 superior, 193 vaginae, 223 coraco-brachialis, 229 corrugator supercilii, 175 cremaster, 214 crico-arytenoid lat., 488 posticus, 488 thyroideus, 488 crureus, 248 cucullaris, 199 deltoid, 228 depressor ang. oris, 181 labii inferioris, 181 labii sup. alaeque nasi, 181 depressor oculi, 177 detrusor urinae, 532 diaphragm, 217 dilatator naris, 179 digastricus, 189 erector clitoridis, 551 penis, 220 spina?, 203 extensor carpi rad. brev. 235 carpi rad. long., 235 carpi ulnaris, 236 coccygis, 206 digiti minimi, 236 digitor. brevis, 258 digitor. com., 235 digitor. longus, 253 indicis, 238 ossis metacarpi, 237 pollicis proprius, 254 primi internodii, 237 sec. internodii, 237 flexor accessorius, 261 brevis digiti minimi, 240 digiti minimi pedis, 262 carpi radialis, 232 ulnaris, 233 digitorum brevis, 260 profundus, 233 sublimis, 232 longus digitjredis, 256 longus pojflnnanus, 233 pedis, 256 ossis metacarpf;W239, 240 pollicis brevis, 239 INDEX. 1>7J Muscles—continued. pedis, 261 longus, 256 gastrocnemius, 254 gemellus inferior, 246 superior, 245 genio-hyo-glossus, 190 hyoideus, 190 gluteus maximus, 244 medius, 244 minimus, 245 gracilis, 251 helicis major, 457 minor, 457 hyo-glossus, 190 iliacus, 249 indicator, 238 infra-spinatus, 227 inter-costales e\terni, 210 interni, 210 interossei manus, 241 pedis, 259 tavter-spinales, 206 mter-transversales, 2o5 Intra-costales, 210 Sechio-cavernosus, 290 larynx, of the, 488 latissimus dorsi, 199 laxator tympani, 459 levator anguli oris, 180 scapulae, 201 ani, 222 glandulae thyroid., 02, labii inferioris, 182 superioris, 180 sup. alaaq. nasi, 163 menti, 182 palati, 194 palpebrae, 177 levatores costarum, 20w lingualis, 191 longissimus dorsi, 203 longus colli, 197 lumbricales manus, 240 pedis, 261 mallei externus, 459 internus, 459 masseter, 182 multifidus spina?, 206 mylo-hyoideus, 190 myrtiformis, 181 naso-Iabialis, 180 obliquus abdom. ext., 212 abdom. int., 214 capitis inferior, 205 superior, 205 oculi inferior, 178 superior, 178 obturator externus, 246 internus, 245 occipito-frontalis, 174 omo-hyoideus, 188 opponens digit, min., 240 pollicis, 239 orbicularis oris, 180 palpebrarum, 175 palato-glossus, 192, 195 pharyngeus, 195 palmaris brevis, 240 longus, 232 . ^ pectineus, 250 ^J^* pectoralis major, 225 minor, 225' peroneus Previa. 258 Muscles—continued. longus, 258 tertius, 254 plantaris, 255 platysma-myoides, 186 popliteus, 256 posterior auris, 185 pronator quadratus, 234 radii teres, 231 psoas magnus, 249 parvus, 216 pterygoideus ext., 183 int., 184 pyramidalis abdom., 216 nasi, 179 pyriformis, 245 quadratus femoris, 246 lumborum, 216 menti, 181 rectus abdominis, 216 capitis ant. maj., 196 min., 196 lateralis, 205 post, maj., 205 min., 205 femoris, 248 oculi externus, 177 inferior, 177 internus, 177 superior, 177 retrahens aurem, 185 rhomboideus major, 201 minor, 201 risorius Santorini, 186 sacro-lumbalis, 203 sartorius, 247 scalenus anticus, 196 posticus, 197 semi-spinalis colli, 205 dorsi, 205 semi-membranosus, 252 semi-tendinosus, 251 serratus magnus, 226 posticus inf., 202 sup., 201 soleus, 255 sphincter ani, 222 internus, 222 spinalis dorsi, 203 splenius capitis, 202 colli, 202 stapedius, 459 sterno-hyoideus, 188 mastoideus, 186 thyroideus, 188 stylo-glossus, 192 hyoideus, 189 pharyngeus, 193 subclavius, 226 subcrureus, 248 subscapularis, 226 superior auris, 184 supinator brevis, 237 longus, 234 supra-spinalis, 206 supra-spinatus, 227 temporal, 182 tensor palati, 195 tarsi, 176 tympani, 459 vagina? fern., 247 teres major, 228 minor, 227 thyro-arytenoideus. 488 572 INDEX. Muscles—continued. epiglottideus, 489 hyoideus, 188 tibialis anticus, 253 posticus, 257 trachelo-mastoideus, 204 tragicus, 457 transversalis abdom., 215 colli, 204 transversus auris, 457 pedis, 262 perinei, 221, 223 trapezius, 199 triangularis oris, 181 sterni, 211 triceps extens. cruris, 248 cubiti, 230 trochlearis, 178 ureters, of the, 533 vastus externus, 248 internus, 248 zygomaticus major, 181 minor, 181 Muscular fibre, 169 Musculi pectinati, 479 Myolemma, 169 Myoline, 171 Myopia, 452 N. Naboth, ovula of, 547 Nagel, Mr., researches of, 528 Nails, 472 Nares, 444 Nasal duct, 456 fossae, 442 Nasmyth, Mr., researches of, 94, 511 Nates cerebri, 379 Nerves. general anatomy, 361 abducentes, 401 accessorius, 404 acromiales, 412 auditory, 403 auricularis anterior, 400 magnus, 412 posterior, 402 brachial, 414 buccal, 399 cardiac, 407 cardiacus inferior, 438 magnus, 439 medius, 438 minor, 439 superior, 438 cervical, 410 cervico-facial, 403 chorda tympani, 402 ciliary, 398 circumflex, 420 claviculares, 412 coccygeal, 426 cochlear, 404 communicans noni, 412 peronei, 428 poplitei, 429 cranial, 393 crural, 424 cutaneous ext. brach., 416 ext. femoralis, 423 int. brachialis, 416 minor, 416 med femoralis, 424 Nee ves—continued. post, femoralis, 429 spiralis, 419 dental anterior, 399 inferior, 400 posterior, 399 descendens noni, 409 digastric, 402 dorsal, 420 eighth pair, 404 facial, 401 femoral, 424 fifth pair, 396 first pair, 393 fourth pair, 395 frontal, 397 gastric, 407 genito-crural, 423 glosso-pharyngeal, 404 gluteal, 428 inferior, 428 gustatory, 400 hypo-glossal, 408 ilio-scrotal, 423 inferior maxillary, 399 infra-trochlear, 396 inguino-cutaneous, 423 intercostal, 420 intercosto-humeral, 421 interosseous anterior, 417 posterior, 419 ischiaticus major, 429 minor, 428 Jacobson's, 404 lachrymal, 397 laryngeal inferior, 407 superior, 406 lingual, 396 lumbar, 422 lumbo-sacral, 426 masseteric, 399 maxillaris inferior, 399 superior, 396 median, 416 molles, 438 motores oculorum, 395 musculo-cutan., arm, 416 leg, 432 musculo-spiral, 419 mylo-hyoidean, 397 nasal, 397 naso-ciliaris, 397 palatine, 435 ninth pair, 408 obturator, 426 occipitalis major, 413 minor, 412 olfactory, 393 ophthalmic, 397 optic, 394 orbital, 398 palatine anterior, 435 posterior, 435 palmar, deep, 417 superficial, 417 pathetici, 395 perforans Casserii, 416 perineal, 428 peroneo-cutaneous, 428 peroneal, 431 £^ petrosal, 434 'I petrosus minor, 436 pharyngeal, 405, 406 phrenic, 413 INDEX. Nerves—continued. plantar, external, 431 internal, 431 pneumogastric, 405 popliteal, 429 oortio dura, 401 mollis, 403 pterygoid, 399 pudendalis, 429 pudic, internal, 428 pulmonary, 407 radial, 419 recurrent, 407 respiratory, external, 415 sacral, 426 saphenous, external, 430 long, 425 short, 425 second pair, 394 seventh pair, 401 sixth pair, 401 spheno-palatine, 435 spinal, 409 spinal accessory, 408 splanchnicus major, 441 minor, 441 stylo-hyoid, 403 subcutaneus malae, 398 sub-occipital, 403 subrufi, 438 subscapular, 415 superficialis colli, 412 cordis, 438 superior maxillary, 398 6upra-orbital, 396 scapular, 415 trochlear, 395 sympatheticus major, 433 temporal, 399 temporo-facial, 403 malar, 400 third pair, 395 thoracic, long, 415 short, 415 thyro-hyoidean, 409 tibialis anticus, 432 posticus, 430 trifacial, 396 trigeminus, 396 trochlearis, 395 tympanic, 402 ulnar, 418 vagus, 404 vestibular, 404 Vidian, 435 Wrisberg, of, 416 Neurilemma, 361 Nipple, 552 Nodulus, 382 Nodus encephali, 3P5 Nose, 442 Nucleus Olivae, 386 Nympha?, 550 O. Oesophagus, 5'J5 Omentum, gastro-splenic, 498 great, 498 lesser, 498 ».%h. Omphalo-mesenteric vessels, 559 Optic commissure, 393 thalami, 378 Orbiculare, os, 459 Orbits, 90 Ossicula auditus, 458 Ossification, 49 Ostium abdominale, 549 uterinum, 549 Otoconites, 466 Ovaries, 549 Ovula Graafiana, 550 Naboth, of, 47 P. Pacchionian glands, 371 Palate, 502 Palmar arch. 306 Palpebrae, 4IJ3 Palpebral ligaments, 454 sinuses, 454 Pancreas, 526 Panizza, researches of, 437 Papilla? of the nail, 472 of the skin, 469 of the tongue, 467 calyciformes, 467 circumvallatae, 467 conicae, 467 filiformes, 467 fungiformes, 468 Parotid gland, 503 Pelvis, 117 viscera of, 532 Penis, 536 Pericardium, 475 Perichondrium, 46 Pericranium, 46 Periosteum, 46 Peritoneum, 497 Perspiratory ducts, 474 Pes accessorius, 37 anserinus, 401 hippocampi, 376 Petit, notice of, 452 Peyer, notice of, 513 Peyer's glands, 513 Phalanges, 113, 128 Pharynx, 504 Pia mater, 371 Pigmentum nigrum, 448 Pillars of the palate, 503 Pineal gland, 379 Pinna, 456 Pituitary gland, 384 membrane, 445 Pleura?, 495 Plexus, aortic, 441 axillary, 414 brachial, 414 cardiac, 440 carotid, 436 cavernosus, 436 cervical, anterior, 411 posterior, 413 choroid, 375 coeliac, 440 coronary, 439 gangliformis, 401 gastric, 440 hepatic, 440 hypogastric, 442 lumbar, 419 mesenteric, inferior, 441 superior, 441 oesophageal, 404 pharyngeal, 402 j74 INDEX. P :.exus—continued. phrenic, 441 prostatic, 340 pterygoid, 330 pulmonary, 403, 439 renal, 441 sacral, 424 solar, 441 spermatic, 441 splenic, 441 submaxillary, 397 supra-renal, 441 uterine, 341 vertebral, 437 vesical, 341 Plica semilunaris, 455 Plicae longitudinales, 509 Pneumogastric lobule, 382 Polypus of the heart, 476 Pomum Adami, 485 Pons Tarini, 385 Varolii, 385, 389 Pores, 471 Portal vein, 349 Portio dura, 401 mollis, 403 Porus opticus, 446 Poupart's ligament, 212 Prepuce, 536 Presbyopia, 452 Processus e cerebello ad testes, 382 clavatus, 386 vermiformes, 384 Promontory, 460 Prostate gland, 534 Prostatic urethra, 538 Protuberantia annularis, 385 Pulmonary artery, 494 plexuses, 494 sinuses, 480 veins, 351 Puncta lachrymalia, 455 vasculosa, 373 Piipil, 448 _ Purkinje, corduscies oi," 45 Pylorus, 506 J Pyramid, 460J Pyramids, anterior, de)6 posteriori 380 of WistaJ, 72 ) • cj I R* ' Raphe, corporis callosi, 373,^ ^ u i Receptaculum chyli, 359 Rectum, 513L.^ Regions, abaominaT7 '4M6"""""""" Reil, island of, 383 Respiratory nerves, 495 tract, 388 Rete mucosum, 471 testis, 543 Retina, 449 Ribs, 101 Ribes, ganglion of, 433 Rima glottidis, 488 Ring, external abdominal, 212 femoral, 278 internal abdominal, 271 Ruga?, 510, 546 Ruysch, notice of, 449 S. MO Vf« ^*U<; Sacculus communis, 465 • -_,.. trai LlB.URtfr Sacculus laryngis, 490 proprius, 465 Salivary glands, 503 Saphenous opening, 273 veins, 344 Scala tympani, 463 vestibuli, 463 Scarf-skin, 430 Scarpa, notice of, 466 Schindylesis, 83 Schneider, notice of, 445 Schneiderian membrane, 445 Sclerotic coat, 445 Scrotum, 540 Searle, Mr., researches of, 482 Sebaceous glands, 470 Semicircular canals, 452 Semilunar fibro-cartilages, 161 valves, 480 Septum auricularum, 478 crurale, 273 lucidum, 376, 389 pectiniforme, 537 scroti, 540 Serous membrane, structure, 5G1 Sesamoid bones, 129 Sheath of the rectus, 216 Sigmoid valves, 480 Sinuses, structure, 337 Sinus, aortic, 480 basilar, 340 cavernous, 340 circular, 340 fourth, 339 lateral, 339 longitudinal, inferior, 339 superior, 338 occipital, anterior, 339 posterior, 339 petrosal, inferior, 340 superior, 340 pocularis, 539 prostatic, 539 pulmonary, 480 ectus or straight. 339 rnomboiaar transverse, 341 "V lsalva, of, 480 Skeleton, 49 Skin, 468 Skull. 58 , ■ „ Socia parotid^ #$ O 1 , Soemmering, notice of, 450 Soft palate, 502 SpeWatifc caMai, 271 cord, 540 Spigel, notice of,"518" Spinal cord, 389 nerves, 409 veins, 348 Spleen, 526 Spongy part of the urethra, 539 Stapes, 458 Stenon, notice of, 503 Stenon's duct, 503 Stomach, 505 Striae, medullares, 376 muscular, 169' Sub-arachnoidean fluid, 371 space, 371 tissue, 372 Sublingual gland, 504 Submaxillary gland, 503 INDEX. Substantia, cinerea, 372 perforata, 383 Sudoriferous ducts, 471 Sudoriparous glands, 471 Sulcus hepatis, 518 longitudinal corda? spinal., 391 Supercilia, 453 Superficial fascia, 264 Supra-renal capsules, 527 Suspensory ligament, liver, 516 penis, 536 Sutures, 83 Sylvius, notice of, 372 Sympathetic nerve, 438 Symphysis, 130 Synarthrosis, 130 Synovia, 137 Synovial,membrane, 136 T. Tapetum, 449 Tarin, Peter, notice of, 374 Tarsal cartilages, 453 Tarsus, 124 Teeth, 92 Tendo Achillis, 254 oculi, 175 Tendon, 169 Tenia'hippocampi, 3*6 semicircularis, 374 Tarini, 374 Tentorium cerebelli, S4>9 Testes cerebri, 379 Testicles, 540 descent, 561 Thalami optici, 378 Thebesius, notice of, V/7 Theca vertebralis, 38* Thoracic duct, 359 Thorax, 475 Thymus gland, 556 Thyro-hyoid membrane, 487 Thyroid axis, 298 cartilage, 485 gland, 492 Tod, Mr., researches of, 457 Tongue, 467 Tonsils, 503 cerebelli, 381 Torcular Herophili, 339 Toynbee, Mr., researches of, 530 Trachea, 491 Tractus motorius, 391 opticus, 390 spiralis, 463 Tragus, 456 Triangles of the neck, 188 Tricuspid valves, 479 Trigone vesicale, 534 Trochlearis, 178 Tuber einereum, 385 Tubercula quadrigemina, 380 Tuberculum Loweri, 478 Tubuli lactiferi, 552 seminiferi, 542 uriniferi, 529 Tunica albuginea oculi, 445 testis, 542 erythroides, 541 nervea, 446 Ruyschiana, 449 vaginalis, 542 oculi, 445 Tunica vasculosa testis, 542 Tutamina oculi, 453 Tympanum, 458 Tyrrell, Mr., researches of, 268 Tyson's glands, 536 U. Umbilical region, 496 Urachus, 532 Ureter, 530 Urethra, female, 544 male, 537 Uterus, 546 Utriculus communis, 465 Uvea, 447 Uvula cerebelli, 382 palati, 503 vesicae, 534 V. Vagina, 545 Vallecula, 371 Valsalva, sinuses of, 480 Valve, arachnoid, 370 Bauhini, 510 coronary, 478 Eustachian, 478 ileo-caecal, 510 mitral, 481 pyloric, 510 rectum, of the, 511 semilunar, 480 Tarin, of, 372 tricuspid, 478 Vieussens, of, 370 Valvula? conniventes, 510 Varolius, notice of, 385 Vasa efferentia, 543 lactea, 358 lymphatica, 357 pompiniformia, 543 recta, 543 vasorum, 281 Vasculum, aberrans, 543 Vas deferens, 540 Veins, 334 structure, 335 angular, 337 auricular, 337 axillary, 343 ozygos major, 348 minor, 348 basilic, 342 cardiac, 349 cava, inferior, 346 superior, 345 cephalic, 343 cerebellar, 338 cerebral, 338 coronary, 349 corpora striata, 374 diploe, 337 dorsalis penis, 346 dorsi-spinal, 348 emulgent, 347 facial, 336 femoral, 344 frontal, 336 Galeni, 338, 377 gastric, 350 hepatic, 348 iliac, 345 576 INDEX. Veins—continued. innominata, 345 intercostal, superior, 348 jugular, 341 lumbar, 347 mastoid, 337 maxillary, internal, 337 median, 343 basilic, 343 cephalic, 343 medulli-spinal, 349 meningo-rachidian, 342, 348 mesenteric, inferior, 349 superior, 349 occipital, 337 ovarian, 347 parietal, 339 popliteal, 344 portal, 349 profunda femoris, 344 prostatic, 346 pulmonary, 351, 495 radial, 343 renal, 347 salvatella, 342 saphenous, external, 344 internal, 344 spermatic, 347 spinal, 348 splenic, 350 subclavian, 343 temporal, 337 temporo-maxillary, 337 Thebesii, 349 thyroid, 342 ulnar, 342 uterine, 346 vertebral, 341, 348 vesical, 346 Velum interpositum, 377 medullare, 380 pendulum palati, 503 Venae comites, 339 Galeni, 378 vorticosae, 448 Ventricle of Arantius, 380 Ventricles of the brain, 378 fifth, 376 fourth, 379 lateral, 373 third, 377 of the heart, 479, 481 of the larynx, 490 Vermiform process, 382 Vertebral aponeurosis, 200 column, 50 Veru montanum, 539 Vesicula? seminales, 535 Vestibule, 462 Vestibulum vaginae, 551 Vibrissa?, 453 Vidius,Vidus, notice of, 435 Vieussens, notice of, 380 Villi, 512 Vitreous humour, 451 Vulva, 550 W Wharton, notice of, 468 Wharton's duct, 504 Willis, notice of, 368 Wilson's muscles, 220 Winslow, notice of, 5*V) Wistar, pyramids of, 73 Wrisberg, nerve of, 416 K. Zinn, notice of, 450 Zonula ciliaris, 450 of Zinn, 450 Zygoma, 64 CATALOGUE OF BLANCHARD & LEA'S MEDICAL AND SURGICAL PUBLICATIONS. PHILADELPHIA, MAY 1, 1854. TO THE MEDICAL PROFESSION. In submitting the following catalogue of our publications in medicine and the collateral sciences, we beg to remark that no exertions are spared to render the issues of our press worthy a continuance of the confidence which they have thus far enjoyed, both as regards the high character of the works themselves, and in respect to every point of typographical accuracy, and mechanical and artistical execution. Gentlemen desirous of adding to their libraries from our list, can in almost all cases procure the works they wish from the nearest bookseller, who can readily order any which he may not have on hand. From the great variation in the expenses of transportation through territories so extensive as those of the United States, prices cannot be the same in all sections of the country, and therefore we are unable to affix retail prices to our publications. Information on this point may be had of booksellers generally, or from ourselves, inquiries in relation to which we shall always be happy to answer. Philadelphia, May 1, 1854. BLANCHARD & LEA. TWO MEDICAL PERIODICALS, FREE OF POSTAGE, FOR FIVE DOLLARS PER ANNUM. THE AMERICAN JOURNAL OF THE MEDICAL SCIENCES, subject to postage, when not paid for in advance,.......$5 00 THE MEDICAL NEWS AND LIBRARY, invariably in advance, - - 1 00 or, both periodicals furnished, free of postage, for Five Dollars remitted in advance. 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 at least two hundred and eighty large octavo pages, appropriately illustrated, wherever necessary, by engravings. It has now been issued regularly for a period of thirty-five years, during a quarter of a century of which it has been under the control of the present editor. Throughout this long space of time, it has maintained its position in the highest rank of medical periodicals both at home and abroad, and has received the cordial support of the entire profession in this country. Its list of Collaborators will be found to contain a large number of the most distinguished names of the pro- fession in every section of the United States, rendering the department devoted to ORIGINAL COMMUNICATIONS full of varied and important matter, of great interest to all practitioners. As the aim of the Journal, however, is to combine the advantages presented by all the different varieties of periodicals, in its > REVIEW DEPARTMENT will be found extended and impartial reviews of all important new works, presenting subjects of novelty and interest, together with very numerous BIBLIOGRAPHICAL NOTICES, including nearly all the medical publications of the day, both in this country and Great Britain, with a choice selection of the more important continental works. This is followed by the a BLANCHARD & LEA'S MEDICAL QUARTERLY SUMMARY, being a very full and complete abstract, methodically arranged, of the IMPROVEMENTS AND DISCOVERIES IN THE MEDICAL SCIENCES. This department of the Journal, so important to the practising physician, is the object of especial care on the part of the editor. It is classified and arranged under different heads, thus faciliiating the researches of the reader in pursuit of particular subjects, and will be found to present a very full and accurate digest of all observations, discoveries, and inventions recorded in every branch of medical science. The very extensive arrangements of the publishers are such as to afford to the editor complete materials for this purpose, as he not only regularly receives ALL THE AMERICAN MEDICAL AND SCIENTIFIC PERIODICALS, but also twenty or thirty of the more important Journals issued in Great Britain and on the Conti- nent, thus enabling him to present in a convenient compass a thorough and complete abstract of everything interesting or important to the physician occurring in any part of the civilized world. An evidence of the success which has attended these efforts may be found in the constant and steady increase in the subscription li^t, which renders it advisable for gentlemen desiring the Journal, to make known their wishes at an early day, in order to secure a year's set with certainty, the publishers having frequently been unable to supply copies when ordered late in the year. To their old subscribers, many of whom have been on their list for twenty or thirty years, the publish- ers teel that no promises are necessary; but those who may desire for the first time to subscribe, can rest assured that no exertion will be spared to maintain the Journal in the high position which it has occupied for so long a period. Bv reference to the terms it will be seen that, in addition to this large amount of valuable and practical information on every branch of medical science, the subscriber, by paying in advance, becomes entitled, without further charge, to THE MEDICAL NEWS AND LIBRARY, a monthly periodical of thirty-two large octavo pages. Its "News Department" presents the current information of the day, while the " Library Department" is devoted to presenting stand- ard works on various branches of medicine. Within a few years, subscribers have thus received, without expense, the following works which have passed through its columns :— WATSON'S LECTURES ON THE PRACTICE OF PHYSIC. BRODIE'S CLINICAL LECTURES ON SURGERY. TODD AND BOWMAN'S PHYSIOLOGICAL ANATOMY AND PHYSIOLOGY OF MAN. 724 pages, with numerous wood-cuts, being all that has yet appeared in England. WEST'S LECTURES ON THE DISEASES OF INFANCY AND CHILDHOOD. MALGAIGNE'S OPERATIVE SURGERY, with wood-cuts, and SIMON'S LECTURES ON GENERAL PATHOLOGY. While the year 1854, presents BENNETT ON PULMONARY TUBERCULOSIS, BEAUTIFULLY ILLUSTRATED ON WOOD. 1^° Subscribers for 1853, who do not possess the commencement of Todd and Bowman's Physiology, can obtain it, in a handsome octavo volume, of 552 pages, with over 150 illustrations, by mail, free of postage, on a remittance of $2 50 to the publishers. It will thus be seen that for the small sum of FIVE DOLLARS, paid in advance, the subscriber will obtain a Quarterly and a Monthly periodical, EMBRACING ABOUT FIFTEEN HUNDRED LARGE OCTAVO PAGES mailed to any part of the United States, free of postage. These very favorable terms are now presented by the publishers with the view of removing all difficulties and objections to a full and extended circulation of the Medical Journal to the office of every member of the profession throughout the United States. The rapid extension of mail facili- ties, will now place the numbers before subscribers with a certainty and dispatch not heretofore attainable; while by the system now proposed, every subscriber throughout the Union is placed upon an equal footing, at the very reasonable price of Five Dollars for two periodicals, without further expense. Those subscribers who do not pay in advance will bear in mind that their subscription of Five Dollars will entitle them to the Journal only, without the News, and that they will be at the expen?e of their own postage on the receipt of each number. The advantage of a remittance when order- ing the Journal will thus be apparent. As the Medical News and Library is in no case sent without advance payment, its subscribers will always receive it free of postage. It should also be borne in mind that the publishers will now take the risk of remittances by mail, only requiring, in cases of loss, a certificate from the subscriber's Postmaster, that the money was duly mailed and forwarded. Ep3 Funds at par at the subscriber's place of residence received in payment of subscriptions. Address, BLANCHARD 5c LEA, Philadelphia. AND SCIENTIFIC PUBLICATIONS. 3 ANALYTICAL COMPENDIUM OF MEDICAL SCIENCE, containing Anatomy, Physiology, Surgery, Midwifery, Chemistry, Materia Medica, Therapeutics, and Practice of Medicine. By John Neill, M. D., and F. G. Smith, M. D. Second and enlarged edition, one thick volume royal l2mo. of over 1000 pages, with 350 illustrations. [2F1 See Neill. ABEL (F. A.), F. C. S. Professor of Chemistry in the Royal Military Academy, Woolwich. AND C. L. BLOXAM, Formerly First Assistant at the Royal College of Chemistry. HANDBOOK OF CHEMISTRY, Theoretical, Practical, and Technical, with a Recommendatory Preface by Dr. Hofmann. In one large octavo volume of 662 pages, with illustrations. {Now Ready.) There was still wanting some book which should ] who resolves to pursue for himself a steady search aid the young analytical chemist through all the , into the chemcal mysteries of creation. For such phases of the science. The " Handbook" of Messrs. ! a student the 'Handbook' will prove an excellent Abel and Bloxam appears to supply that want. As ■ guide, since he will find in it, in t merely the most Dr. Hofmann says in his brief Preface. " The pre- approved modes of analytical investigation, but sent volume is a synopsis of their (the authors') ex- j descriptions of the apparatus necessary, with such perience in laboratory teaching ; it gives the neces- \ manipulatory details as rendered Faraday's ' Che- sary instruction in chemical manipulation, a concise inical Manipulations' so valuable at the time of its account of general chemistry as far as it is involved publication. Beyond this, the importance of the in the operations of the laboratory, and lastly, quali- work is increased by the introduction of much of the tative and quantitative analysis. It must be under- | technical chemistry of the manufactory."—Athe- stood that this is a work fitted for the earnest student, nmum. ASHWELL (SAMUEL), M.D. A PRACTICAL TREATISE ON THE DISEASES PECULIAR TO WOMEN. Illustrated by Cases derived from Hospital and Private Practice. With Additions by Paul Beck Goddard, M. D. Second American edition. In one octavo volume, of 520 pages. ARNOTT (NEILL), M. D. ELEMENTS OF PHYSICS; or Natural Philosophy, General and Medical. Written for universal use, in plain or non-technical language. A new edition, by Isaac Hays, M. D. Complete in one octavo volume, of 484 pages, with about two hundred illustrations. BENNETT (J. HUGHES), M.D., F. R. S. E., Professor of Clinical Medicine in the University of Edinburgh, &c. THE PATHOLOGY AND TREATMENT OF PULMONARY TUBERCU- LOSIS, and on the Local Medication of Pharyngeal and Laryngeal Diseases frequently mistaken for or associated with, Phthisis, in one handsome octavo volume, with beautiful wood-cuts. Now publishing in the " Medical News and Library" for 1854, and furnished gratis to advance- paying subscribers to the American Journal of the Medical Sciences. How it may be most effectually carried into prac- tice, our readers will leurn from Dr. Bennett's pages, especially from the histories of the valuable and in- teresting cases which he records. Indeed, if the au- thor had only reported these cases he would have benefited his profession, and deserved our thanks. As it is, however, his whole volume is so replete with valuable matter, that we feel bound to recommend our readers, one and all, to peruse it.—Lond. Lancet. The elegant little treatise before us shows how faithfully and intelligently these investigations have been pursued, and how successfully the author's Btudies have resulted in clearing up some of the most doubtful points and conflicting doctrines hitherto entertained in reference to the history and treatment of pulmonary tuberculosis.—N. Y. Journal of Medi- cal and Collateral Science, March, 1854. BENNETT (HENRY), M. D. A PRACTICAL TREATISE ON INFLAMMATION OF THE UTERUS, ITS CERVIX AND APPENDAGES, and on its connection with Uterine Disease. Fourth American, from the third and revised London edition. In one neat octavo volume, of 430 pages, with wood-cuts. (Now Ready.) This edition will be found materially improved over its predecessors, the author having carefully revised it, and made considerable additions, amounting to about seventy-five pages. This edition has been carefully revised and altered, and various additions have been made, which render it more complete, and, if possible^ more worthy of the high appreciation in which it is held by the medical profession throughout the world. A copy should be in the possession of every physician.— Charleston Med. Journal and Review, March, 1854. We are firmly of opinion that in proportion as n knowledge of uterine diseases becomes more appre- c ated. this work will be proportionably established ■A3 a text-book in the profession.—The Lancet. When, a few years back, the first edition of the present work was published, the subject was one almost entirely unknown to the obstetrical celebrities of the day; and eveu now we have reason to know that the bulk of the profession are not fully alive to the importance and frequency of the disease of which it takes cognizance. The present edition is so much enlarged, altered, and improved, that it can scarcely be considered the same work.—Dr. Banking's Ab- stract. Few works issue from the medical press which are at once original and sound in doctrine j but such, we feel assured, is the admirable treatise now before us. The important practical precepts which the author inculcates are all rigidly deduced from facts. . . . Every page of the book is good, and eminently practical. ... So far as we know and believe, it is the best work on the subject of which it treats.— Monthly Journal of Medical Science. 4 BLANCHARD &: LEA'S MEDICAL BEALE (LIONEL JOHN), M. R. C. S., Sec. THE LAWS OF HEALTH IN RELATION TO MIND AND BODY. A Series of Letters from an old Practitioner to a Patient. In one handsome volume, royal 12mo., extra cloth. BILLING (ARCHIBALD), M. D. THE PRINCIPLES OF MEDICINE. Second American, from the Fifth and Improved London edition. In one handsome octavo volume, extra cloth, 250 pages. BLAKISTON (PEYTON), M. D., F. R. S., &.C. PRACTICAL OBSERVATIONS ON CERTAIN DISEASES OF THE CHEST, and on the Principles of Auscultation. In one volume.. Svo., pp. 384. BURROWS (GEORGE), M. D. ON DISORDERS OF THE CEREBRAL CIRCULATION, and on the Con- nection between the Ailectiuns of the Brain and Diseases of the Heart. In one Svo. vol., wiih colored plates, pp. 216. BUDD (GEORGE), M. D., F. R. S., Professor of Medicine, in King's College, London. ON DISEASES OF THE LIVER. Second American, from the second and enlar^d London edition. In one very handsome octavo volume, with four beautifully colored plate" and numerous wood-cuts. pp.'4>S. New edition. (Just Issued.) The reputation which this work has obtained as a full and practical treatise on an important class of diseases will not be diminished by this improved and enlarged edition. It has been carefully and thoroushlv revised by the author; the number of plates has been increased, and the style of it* me- chanical execution will be found materially improved. work must be the authority of the great mass ■ «' British practitioners on the hepatic diseases ; ami ii is satisfactory that the subject has been taken up by The full digest we have given of the new matter introduced into the present volume, is evidence of the value we place on it. The fact that the profes- sion has required a second edition of a monograph such as that before ns, bears honorable testimony to its usefulness. For many years, Dr. Budd's so able and experienced a physician.—British and Foreign Medieo-Chimrgical Review. BUCKLER (T. H.), M. D., Formerly Physician to the Baltimore Almshouse Infirmary, 4kc. ON THE ETIOLOGY, PATHOLOGY, AND TREATMENT OF FIBRO- BRONCH1TIS AND KHEUMATIC PNEUMONIA. In one handsome octavo volume, extra cloth. (-Vote Ready.) The concluding chapter on Treatment is full of [ rather than the mere closet student.—.V. J. Medical sound practical suggestions, which make this emi- Reporter, March, l?o-l. nently a book to be prized by the '• working doctor" | BLOOD AND URINE (MANUALS ON). BY JOHN WILLIAM GRIFFITH, G. OWEN REESE, AND ALFRED MARKWICK. One thick volume, royal 12mo., extra cloih, with plates, pp. 460. BRODIE (SIR BENJAMIN O, M. D., &.c. CLINICAL LECTURES OX SURGERY. 1 vol. Svo., cloth. 350 pp. BY THS SAME AUTHOR. SELECT SURGICAL WORKS. 1 vol. Svo. leather, containing Clinical Lectures on Surgery, Diseases of the Joints and Diseases of the Urinary Orjjan*. BIRD (GOLDING), A. M., M. D., fitc. URINARY DEPOSITS: THEIR DIAGNOSIS, PATHOLOGY, AND THERAPEUTICAL INDICATIONS. A new and enlarged American, from the last improved London edition. With over sixty illustration*. In one royal 12mo. volume, extra cloth. Tne new edition of Dr. Bird's work, though not' suits of those microscopical and chemical researches increased iu size, has been greatly modified, and regarding the physiology and pathology of the uri- mueu o( it rewritten. It now presents, in a com- nary secretion, which have contribureii so much lo pendiousform. the gist of all that is known and re- j the increase of our diagnostic powers, and to the halite in this department. From its terse style and ; extension and satisfactory employment of our thera- convenientsize.it is particularly applicable to the peutic resources. In the preparation of this new stutietit. to whom we cordially commend it — The edition of his work, it is obvious that Dr. Golding Medical Examiner. Bird has spared no pains to render it a faithful repre- It can scarcely be necessary for nsto sav anything sentation of the present state of scientific knowledge of the merits of This wellWwn Treatise winch so | ^^S^^/SSJ^***"1***"* ^r"*» admirably brings into practical applicant the re- • Medtco-Chirurgttal Rtvtew. BY THE SAMS AUTHOR. ELEMENTS OF NATURAL PHILOSOPHY; being an Experimental Intro- duction to the Phvsical Science*. Illustrated with nearly four hundred wood-cuts. From the third London edition. In one neat volume, royal 12mo. pp. 402. AND SCIENTIFIC PUBLICATIONS. 5 BARTLETT (ELISHA), M. D., Professor of Materia Medica and .Medical Jurisprudence in the College of Physicians and Surgeons, New York. THE HISTORY, DIAGNOSIS, AND TREATMENT OF THE FEVERS OF THE UNITED STATES. Third edition, revised and improved. In one octavo volume, of six hundred pages, beautifully printed, and strongly bound. In preparing a new edition of this standard work, the author has availed himself of such obser- vations and investigations as have appeared since the publication of his last revision, and he has endeavored in every way to render it worthy of a continuance of the very marked favor with which it has been hitherto received. The masterly and elegant treatise, by Dr. Bartlett is invaluable to the American student and practi- tioner.—Dr. Holmes-s Report to the Nat. Med. Asso- ciation. We regard it, from the examination we have made of it, the best work on fevers extant in our language, and as such cordially recommend it to the medical public.—St. Louis Medical and Surgical Journal. Take it altogether, it is the most complete history of our fevers which has yet been published, and every practitioner should avail himself of its con- tents.— The Western Lancet. Of the value and importance of such a work, it is needless here to speak; the profession of the United States owe much to the author for the very able volume which he has presented to them, and for the careful and judicious manner in which he has exe- cuted his task. No one volume with which we are acquainted contains so complete a history of our fevers as this. To Dr. Bartlett we owe our best thanks for the very able volume he has given us, as embodying certainly the most complete, methodical, and satisfactorv account of our fevers anywhere to be met with.— The Charleston Med. Journal and. Review. BOWMAN (JOHN E.), M.D. PRACTICAL HANDBOOK OF MEDICAL CHEMISTRY. In one neat volume, royal 12mo., with numerous illustrations, pp. 288. BY THE SAME AUTHOR. INTRODUCTION TO PRACTICAL CHEMISTRY, INCLUDING ANA- LYSIS. With numerous illustrations. In one neat volume, royal 12mo. pp.350. BARLOW (GEORGE H.), M. D. A MANUAL OF THE PRINCIPLES AND PRACTICE OF MEDICINE. In one octavo volume. (Preparing.) CYCLOP/EDIA OF PRACTICAL MEDICINE. Edited hy Dunglison, Forbes, Tweedie, and Conolly, in four large octavo volumes, strongly bound. B®~ See Dunglison. COLOMBAT DE L'ISERE. A TREATISE ON THE DISEASES OF FEMALES, and on the Special Hygiene of their Sex. Translated, with many Notes and Additions, by C. D. Meigs, M. D. Second edition, revised and improved. In one large volume, octavo, with numerous wood-cuts. pp. 720. The treatise of M. Colombat is a learned and la- I M. Colombat De L'Isere has not consecrated ten borious commentary on these diseases, indicating years of studious toil and research to the frailer sex very considerable research, great accuracy of judg- I in vain; and although we regret to hear it is at the ment, and no inconsiderable personal experience. . expense of health, he has imposed a debt of gratitude With the copious notes and additions of its experi- | as well upon the profession, as upon the mothers and enced and very erudite translator and editor, Dr. daughters of beautiful France, which that gallant Meigs, it presents, probably, one of the most corn- i nation knows best how to acknowledge.—New Or- plete and comprehensive works on the subject we leans Medical Journal. possess.—American Med. Journal. COPLAND (JAMES), M. D., F. R. S., &c. OF THE CAUSES, NATURE, AND TREATMENT OF PALSY AND APOPLEXY, and of the Forms, Seats, Complications, and Morbid Relations of Paralytic and Apoplectic Diseases. In one volume, royal 12mo., extra cloth, pp. 326. CHAPMAN (PROFESSOR N.), M. D., &.c. LECTURES ON FEVERS, DROPSY, GOUT, RHEUMATISM, &c. &c. In one neat 8vo. volume, pp. 450. CLYMER (MEREDITH), M. D., &.c. FEVERS: THEIR DIAGNOSIS, PATHOLOGY, AND TREATMENT. Prepared and Edited, with large Additions, from the Essays on Fever m Tweedie's Library of Practical Medicine. In one octavo volume, of 600 pages. CARSON (JOSEPH), M. D., Professor of Materia Medica and Pharmacy in the University of Pennsylvania. SYNOPSIS OF THE COURSE OF LECTURES ON MATERIA MEDICA AND PHARMACY, delivered in the University of Pennsylvania. In one very neat octavo volume, of 208 pages. 6 BLANCHARD & LEA'S MEDICAL CARPENTER (WILLIAM B.), M. D., F. R. S., &c, Examiner in Physiology and Comparative Anatomy in the University of London. PRINCIPLES OF HUMAN PHYSIOLOGY; with their chief applications to Psychology, Pathology, Therapeutics, Hygiene, and Forensic Medicine. Fifth American, from Ihe fourth and enlarged London edition. With three hundred and fourteen illustrations. Edited, with additions, by Francis Gurney Smith, M. D., Professor of the Institutes of Medicine in the Pennsylvania Medical College, &c. In one very large and beautiful octavo volume, of about 1100 large pages, handsomely printed and strongly bound in leather, with raised bands. New edition. (Lately Issued.) This edition has been printed from sheets prepared for the purpose by the author, who has introduced nearly one hundred illustrations not in the London edition; while it has also enjoyed the advantage of a careful superintendence on the part of the editor, who has added notices of such more recent investigations as had escaped the author's attention. Neither care nor expense has been spared in the mechanical execution of the work to render it superior to former editions, and it is confidently presented as in every way one of the handsomest volumes as yet placed before the medical profession in this country. The most complete work on the science in our language.—Am. Med. Journal. The most complete exposition of physiology which any language can at present give.—Brit, and For. Med.-Chirurg. Review. The best text-book in the language on this ex- tensive subject.—London Med. Times. A complete cyclopaedia of this branch of science. —N. Y. Med. Times. The standard of authority on physiological sub- jects. * * * In the present edition, to particularize the alterations and additions which have been made, would require a review of the whole work, since scarcely a subject has not been revised and altered, added to, or entirely remodelled to adapt it to the present state of the science.—Charleston Med. Journ. Any reader who desires a treatise on physiology may feel himself entirely safe in ordering this.— Western Med. and Surg. Journal. From this hasty and imperfect allusion it will be Been by our readers that the alterations and addi- tions to this edition render it almost a new work— and we can assure our readers that it is one of the best summaries of the existing facts of physiological science within the Teach of the English student and physician.—iV. Y. Journal of Medicine. The profession of this country, and perhaps also of Europe, have anxiously and for some time awaited the announcement of this new edition of Carpenter's Human Physiology. His former editions have for many years been almost the only text-book on Phy- siology in all our medical schools, and its circula- tion among the profession has been unsurpassed by tended notice in this place. At every point where I any work in any department of medical science. the recent diligent labors of organic chemists and It is quite unnecessary for us to speak of this mlcrographers have furnished interesting and valu- work as its merits would justify. The mere an- able facts, they have been appropriated, and no pains nouncement of its appearance will afford the highest have been spared, in so incorporating and arranging pleasure to every student of Physiology, while its them that the work may constitute one harmonious perusal will be of infinite service in advancing system.—Southern Med. and Surg. Journal. ' physiological science.—Ohio Med. and Surg. Journ. BY THE SAME AUTHOR. (In PreiS.) PRINCIPLES OF GENERAL AND COMPARATIVE PHYSIOLOGY. Intended as an Introduction to the Study of Human Physiology; and as a Guide to the Philo- sophical pursuit of Natural History. New and improved edition. In one large and handsome octavo volume, with several hundred beautiful illustrations. The very thorough revision, and extensive alterations made by the author, have caused a delay in the promised appearance of this work. It is now, however, at press, and may be expected for publication during the ensuing summer. A very large number of new and important illustrations have been prepared for it, and the publishers trust to render the volume worthy of its extended reputation in every point of typographical finish, as one of the handsomest productions of the American press. A few notices of the former edition are appended. We have thus adverted to some of the leading "additions and alterations," which have been in- troduced by the author into this edition of his phy- siology. These will be found, however, very far to exceed the ordinary limits of a new edition, "the old materials having been incorporated with the now, rather than the new with the old." It now certainly presents the most complete treatise on the subject within the reach of the American reader; and while, for availability as a text-book, we may perhaps regret its growth in bulk, we are sure that the student of physiology will feel the impossibility of presenting a thorough digest of the facts of the science within a more limited compass.—Medical Examiner. The greatest, the most reliable, and the best book on the subject which we know of in the English language.—Stethoscope. The most complete work now extant in our lan- guage.—N. O. Med. Register. The changes are too numerous to admit of an ex- Without pretending to it, it is an Encyclopedia of the subject, accurate and complete in all respects— a truthful reflection of the advanced state at which the science has now arrived.—Dublin Quarterly Journal of Medical Science. A truly magnificent work—in itself a perfect phy- siological study.—Ranbing's Abstract. This work stands without its fellow. It is one few men in Europe could have undertaken; it is one no man, we believe, could have brought to so suc- cessful an issue as Dr. Carpenter. It required for its production a physiologist at once deeply read in the labors of others, capable of taking a general, critical, and unprejudiced view of those labors and of combining the varied, heterogeneous materials at his disposal, so as to form an harmonious whole. We feel that this abstract can give the reader a very imperfect idea of the fulness of this work, and no idea of its unity, of the admirable manner in which material has been brought, from the most various sources, to conduce to its completeness, of the lucid- ity of the reasoning it contains, or of the clearness of language in which the whole is clothed. Not the profession only, but the scientific world at large, must feel deeply indebted to Dr. Carpenter for this great work. It must, indeed, add largely even to his high reputation.—Medical Times. by the same author. (Preparing.) THE MICROSCOPE AND ITS REVELATIONS. In one handsome volume, beautifully illustrated with plates and wood-cuts. AND SCIENTIFIC PUBLICATIONS. 7 CARPENTER (WILLIAM B.), M. D., F. R. S., Examiner in Physiology and Comparative Anatomy in the Upiversity of London. ELEMENTS (OR MANUAL) OF PHYSIOLOGY, INCLUDING PHYSIO- LOGICAL ANATOMY. Second American, from a new and revised London edition. With one hundred and ninety illustrations. In one very handsome octavo volume. In publishing the first edition of this work, its title was altered from that of the London volume, by the substitution of the word " Elements" for that of " Manual," and with the author's sanction the title of " Elements" is still retained as being more expressive of the scope of the treatise. A comparison of the present edition with the former one will show a material improvement, the author having revised it thoroughly, with a view of rendering it completely on a level with the most advanced state of the science. By condensing the less important portions, these numerous additions have been introduced without materially increasing the bulk of the volume, and while numerous illustrations have been added, and the general execution of the work improved, it has been kept at its former very moderate price. To say that it is the best manual of Physiology now before the public, would not do sufficient justice to the author.—Buffalo Medical Journal. In his former works it would seem that he had exhausted the subject of Physiology. In the present, he gives the essence, as it were, of the whole.—N. Y. Journal of Medicine. Those who have occasion for an elementary trea- tise on Physiology, cannot do better than to possess themselves of the manual of Dr. Carpenter.—Medical Examiner. The best and most complete expose^ of modern Physiology, in one volume, extant in the English language.—St. Louis Medical Journal. With such an aid in his hand, there is no excuse for the ignorance often displayed respecting the sub- jects of which it treats. From its unpretending di- mensions, it may not be so esteemed by those anxious to make a parade of their erudition; but whoever masters its contents will have reason to be proud of his physiological acquirements. The illustrations are well selected and finely executed.—Dublin Med. Press. BY THE SAME AUTHOR. A PRIZE ESSAY ON THE USE OF ALCOHOLIC LIQUORS IN HEALTH AND DISEASE. New edition, with a Preface by D. F. Condie, M. D., and explanations of scientific words. In one neat 12mo. volume. (Now Ready.) This new edition has been prepared with a view to an extended circulation of this important little work, which is universally recognized as the best exponent of the laws of physiology and pathology applied to the subject of intoxicating liquors, in a form suited both for the profession and the public. To secure a wider dissemination of its doctrines the publishers have done up copies in flexible cloth, suitable for mailing, which will be forwarded through the post-office, free, on receipt of fifty cents. Societies and others supplied in quantities for distribution at a liberal deduction. CHELIUS (J. M.), M. D., Professor of Surgery in the University of Heidelberg, &c. A SYSTEM OF SURGERY. Translated from the German, and accompanied with additional Notes and References, by John F. South. Complete in three very large octavo volumes, of nearly 2200 pages, strongly bound, with raised bands and double titles. We do not hesitate to pronounce it the best and most comprehensive system of modern surgery with which we are acquainted.—Medico-Chirurgical Re- view. The fullest and ablest digest extant of all that re- lates to the present advanced state of surgical pa- thology.—American Medical Journal. As complete as any system of Surgery can Well be.—Southern Medical and Surgical Journal. The most learned and complete systematic treatise now extant.—Edinburgh Medical Journal. A complete encyclopaedia of surgical science—a very complete surgical library—by far the most complete and scientific system of surgery in the English language.—N. Y. Journal of Medicine. The most extensive and comprehensive account of the art and science of Surgery in our language.— Lancet. CHRISTISON (ROBERT), M. D., V. P. R. S. E., &.C A DISPENSATORY; or, Commentary on the Pharmacopoeias of Great Britain and the United States; comprising the Natural History, Description, Chemistry, Pharmacy, Ac- tions, Uses, and Doses of the Articles of the Materia Medica. Second edition, revised and im- proved, with a Supplement containing the most important New Remedies. With copious Addi- tions, and two hundred and thirteen large wood-engravings. By R. Eglesfeld Griffith, M. D. In one very large and handsome octavo volume, of over 1000 pages. It is not needful that we should compare it with the other pharmacopoeias extant, which enjoy and merit the confidence of the profession : it is enough to say that it appears to us as perfect as a Dispensa- tory, in the present state of pharmaceutical science, could be made. If it omits any details pertaining to this branch of knowledge which the student lias a right to expect in such a work, we confess the omis- sion has escaped our scrutiny. We cordially recom- mend this work to such of our readers as are in need of a Dispensatory. They cannot make choice of a better.—Western Journ. of Medicine and Surgery. There is not in any language a more complete and perfect Treatise.—N. Y. Annalist. In conclusion, we need scarcely say that we Btrongly recommend this work to all classes of our readers. Asa Dispensatory and commentary on the Pharmacopoeias, it is unrivalled in the English or any other language.—The Dublin Quarterly Journal. We earnestly recommend Dr. Christison'g Dis- pensatory to all our readers, as an indispensable companion, not in theStudy only, but in the Surgery also.—British and Foreign Medical Review. 8 BLANCHARD & LEA'S MEDICAL CONDIE (D. F.), M. D., &c. A PRACTICAL TREATISE ON THE DISEASES OF CHILDREN. Fourth edition, revised and augmented. In one large volume, 8vo., of nearly 750 pages. (Just Issued.) From the Author's Preface. The demand for another edition has afforded the author an opportunity of again subjecting the entire treatise to a careful revision, and of incorporating in it every important observation recorded since the appearance of the last edition, in reference to the pathology and therapeutics of the several diseases of which it treats. In the preparation of the present edition, as in those which have preceded, while the author has appropriated to his use every important fact that he has found recorded in the works of others, having a direct bearing upon either of the subjects of which he treats, and the numerous valuable observations—pathological as well as practical—dispersed throughout the pages of the medical journals of Europe and America, he has, nevertheless, relied chiefly upon his own observations and experience, acquired during a long and somewhat extensive practice, and under circumstances pe- culiarly well adapted for the clinical study of the diseases of early life. Every species of hypothetical reasoning has, as much as possible, been avoided. The author has endeavored throughout the work to confine himself to a simple statement of well-ascertained patho- logical facts, and plain therapeutical directions—his chief desire being to render it what its title imports it to be, a practical treatise on the diseases of.children. Dr. Condie's scholarship, acumen, industry, and practical sense are manifested in this, as in all his numerous contributions to 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 practitioner in this country will rise with the great- est satisfaction —Western Journal of Medicine and Surgery. One of the best works upon the Diseases of Chil- dren in the English language.—Western Lancet. Perhaps the most full and complete work now be- fore the profession of the United States; indeed, we may say in the English language. It is vastly supe- rior to most of its predecessors.—Transylvania Med. Journal. We feel assured from actual experience that no physician's library can be complete withont a copy of this work.—N. Y. Journal of Medicine. A veritable pediatric encyclopaedia, and an honor to American medical literature.—Ohio Medical and Surgical Journal. We feel persuaded that the American medical pro- fession 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. COOPER (BRANSBY B.), F. R. S., Senior Surgeon to Guy's Hospital, &c. LECTURES ON THE PRINCIPLES AND PRACTICE OF SURGERY. In one very large octavo volume, of 750 pages. (Lately Issued). For twenty-five years Mr. Bransby Cooper has been surgeon to Guy's Hospital; and the volume before us may be said to consist of an account of the results of his surgical experience during that long period. We cordially recommend Mr. Bransby Cooper's Lectures as a most valuable addition to our surgical literature, and one which cannot fail to be of service both to students and to those who are actively engaged in the practice of their profes- sion.—The Lancet. COOPER (SIR ASTLEY P.), F. R. S., &c. A TREATISE ON DISLOCATIONS AND FRACTURES OF THE JOINTS. Edited by Bransby B. Cooper, F. R. S , &c. With additional Observations by Prof. J. C. Warren. A new American edition. In one handsome octavo volume, with numerous.illustra- tions on wood. BY THE SAME AUTHOR. ON THE ANATOMY AND TREATMENT OF ABDOMINAL HERNIA. One large volume, imperial 8vo., with over 130 lithographic figures. BY THE SAME AUTHOR. ON THE STRUCTURE AND DISEASES OF THE TESTIS AND ON THE THYMUS GLAND. -One vol. imperial 8vo., with 177 figures, on29 plates'. BY THE SAME AUTHOR. ON THE ANATOMY AND DISEASES OF THE BREAST, with twenty- hve Miscellaneous and Surgical Papers. One large volume, imperial 8vo., with 252 figures on 36 plates. These last three volumes complete the surgical writings of Sir Astley Cooper. They are very handsomely printed, with a large number of lithographic plates, executed in the best style, and are presented at exceedingly low prices. AND SCIENTIFIC PUBLICATIONS. 9 CHURCHILL (FLEETWOOD), M. D., M. R. I. A. ON THE THEORY AND PRACTICE OF MIDWIFERY. A new American, from the last and improved English edition. Edited, with Notes and Additions, by D. Francis Condie, M. D., author of a "Practical Treatise on the Diseases of Children," dec. With 139 illustrations. In one very handsome octavo volume, pp. 510. (Lately Issued.) To bestow praise on a book that has received such marked approbation would be superfluous. We need only say, therefore, that if the first edition was thought worthy of a favorable reception by the medical public, we can confidently affirm that this will be found much more so. The lecturer, the practitioner, and the student, may all have recourse to its pages, and derive from their pelusal much in- terest and instruction in everything relating to theo- retical and practical midwifery.—Dublin Quarterly Journal of Medical Science. A work of very great merit, and such as we can confidently recommend to the study of every obste- tric practitioner.—London Medical Gazette. 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 preference to all others.—Southern Medical and Surgical Journal. The most popular work on midwifery ever issued from the American press.—Charleston Med. Journal. Were we reduced to the necessity of having but one work on midwifery, and permitted to choose, we would unhesitatingly take Churchill.—Western Med. and Surg. Journal. It is impossible to conceive a more useful and elegant manual than Dr. Churchill's Practice of Midwifery.—Provincial Medical Journal. Certainly, in our opinion, the very best work on the subject which exists.—N. Y. Annalist. We regard this volume as possessing more claims to completeness than any other of the kind with which we are acquainted. Most cordially and earn- estly, therefore, do we commend it to our profession- al brethren, and we feel assured that the stamp of their approbation will in due time be impressed upon it. After an attentive perusal of its contents, we hesitate not to say, that it is one of the most com- prehensive ever written upon the diseases of chil- dren, and that, for copiousness of reference, extent of research, and perspicuity of detail, it is scarcely lo be equalled, and not to be excelled, in any lan- guage.—Dublin Quarterly Journal. After this meagre, and we know, very imperfect notice of Dr. Churchill's work, we shall conclude by saying, that it is one that cannot fail from its co- piousness, extensive research, and general accuracy, to exalt still higher the reputation of the author in this country. The American reader will be particu- larly pleased to find that Dr. Churchill has done full justice throughout his work to the various A merican authors on this subject. »The names of Dewees, Eberle, Condie, and Stewart, occur on nearly every page, and these authors are constantly referred to by the author in terms of the highest praise, and with the most liberal courtesy.— The Medical Examiner. To these papers Dr. Churchill has appended notes, embodying whatever information has been laid be- fore the profession since their authors' time. He has also prefixed to the Essays on Puerperal Fever, which occupy the larger portion of the volume, an interesting historical sketch of the principal epi- i No work holds a higher position, or is more de- i serving of being placed in the hands of the tyro, s the advanced student, or the practitioner.—Medical b Examiner. s e Previous editions, under the editorial supervision e of Prof R. M. Huston, have been received with - marked favor, and they deserved it; but this, re- ■ printed from a very late Dublin edition, carefully / revised and brought up by the author to the present time, does present an unusually accurate and able exposition of every important particular embraced 1 in the department of midwifery. * * The clearness, directness, and precision of its teachings, together with the great amount of statistical research which its text'bxhibits, have served to place it already in . the foremost rank of works in this department of re- ; medial science.—N. O. Med. and Surg. Journal. In our opinion, it forms one of the best if not the very best text-book and epitome of obstetric science 1 which we at present possess in the English lan- . guage.— Monthly Journal of Medical Science. ' The clearness and precision of style in which it is ' written, and the great amount of statistical research 1 which it contains, have served to place it in the first rankof works in this department of medical science. 1 —N. Y. Journal of Medicine. Few treatises will be found better adapted as a text-book for the student, or as a manual for the i frequent consultation of the young practitioner.— American Medical Journal. The present volume will sustain the reputation acquired by the author from his previous works. The reader will find in it full and judicious direc- tions for the management of infants at birth, and a compendious, but clear account of the diseases to which children are liable, and the most successful mode of treating them. We must not close this no- tice without calling attention to the author's style, which is perspicuous and polished to a degree, we regret to say, not generally characteristic of medical works. We recommend the work of Dr. Churchill most cordially, both to students and practitioners, as a valuable and reliable guide iu the treatment of the diseases of children.—Am. Journ. of the Med. Sciences. We know of no work on this department of Prac- tical Medicine which presents so candid and unpre- judiced a statement or posting up of our actual knowledge as this.—N. Y. Journal of Medicine. Its claims to merit both as a scientific and practi- cal work, are of the highest order. Whilst we would not elevate it above every other treatise on the same subject, we certainly believe that very few are equal to.it, and none superior.—Southern Med. and Surgical Journal. demies of that disease. The whole forms a very valuable collection of papers, by professional writers of eminence, on some of the most important accidents to which the puerperal female is liable.—American Journal of Medical Sciences. BY THE SAME AUTHOR. ON THE DISEASES OF INFANTS AND CHILDREN. In one large and handsome volume of over 600 pages. BY THE SAME AUTHOR. ESSAYS ON THE PUERPERAL FEVER, AND OTHER DISEASES PE- CULIAR TO WOMEN. Selected from the writings of British Authors previous to the close of the Eighteenth Century. In one neat octavo volume, of about four hundred and fifty pages. 10 BLANCHARD & LEA'S MEDICAL CHURCHILL (FLEETWOOD), M. D., M. R. I. A., &c. ON THE DISEASES OF WOMEN; including those of Pregnancy and Child- bed. A new American edition, revised by the Author. With Notes and Additions, by D Fran- cis Condie, M. D., author of "A Practical Treatise on the Diseases of Children." In one large and handsome octavo volume, with wood-cuts, pp. 684. (Just Issued.) From the Author's Preface. In reviewing this edition, at the request of my American publishers, I have inserted several new sections and chapters, and I have added, I believe, all the information we have derived from recent researches; in addition to which the publishers have been fortunate enough to secure the services of an able and highly esteemed editor in Dr. Condie. We now regretfully take leave of Dr. Churchill's book. Had our typographical limits permitted, we should gladly have borrowed more from its richly stored pages. In conclusion, we heartily recom- mend it to the profession, and would at the same time express our firm conviction that it will not only add to the reputation of its author, but will prove a work of great and extensive utility to obstetric practitioners.—Dublin Medical Press. Former editions of this work have been noticed in previous numbers of the Journal. The sentiments of high commendation expressed in those notices, have only to be repeated in this; not from the fact that the profession at large are not aware of the high merits which this work really possesses, but from a desire to see the principles and doctrines therein contained more generally recognized, and more uni- versally carried out in practice.—N. Y. Journal of Medicine. We know of no author who deserves that appro- bation, on "the diseases of females," to the same extent that Dr. Churchill does. His, indeed, is the only thorough treatise we know of on the subject; and it may be commended to practitioners and stu- dents as a masterpiece in its particular department. The former editions of this work have been com- mended strongly in this journal, and they have won their way to an extended, and a well-deserved popu- larity. This fifth edition, before us, is well calcu- lated to maintain Dr. Churchill's high reputation. It was revisedand enlarged by the author, for hia American publishers, and it seems to us that there ia scarcely any species of desirable information on its subjects that may not be found in this work.—The Western Journal of Medicine and Surgery. We are gratified to announce a new and revised edition of Dr. Churchill's valuable work on the dis- eases of females We have ever regarded it as one of the very best works on the subjects embraced within its scope, in the English language; and the present edition, enlarged and revised by the author, renders it still more entitled to the confidence of the profession. The valuable notes of Prof. Huston have been retained, and contribute, in no small de- gree, to enhance the value of the work. It is a source of congratulation that the publishers have permitted the author to be, in this instance, his own editor, thus securing all the revision which an author alone is capable of making.—The Western Lancet. Asa comprehensive manual for students, or a work of reference for practitioners, we only speak with common justice when we say that it surpasses any other that has ever issued on the same sub- ject from the British press.—The Dublin Quarterly Journal. DEWEES (W. P.), M.D., &c. A COMPREHENSIVE SYSTEM OF MIDWIFERY. Illustrated by occa- sional Cases and many Engravings. Twelfth edition, with the Author's last Improvements and Corrections. In one octavo volume, of 600 pages. (Just Issued.) BY THE SAME AUTHOR. A TREATISE ON THE PHYSICAL AND MEDICAL TREATMENT OF CHILDREN. Tenth edition. In one volume, octavo, 548 pages. (Just Issued.) BY THE SAME AUTHOR. A TREATISE ON THE DISEASES OF FEMALES. one volume, octavo, 532 pages, with plates. (Just Issued.) Tenth edition. In DICKSON (PROFESSOR S. H.), M.D. ESSAYS ON LIFE, SLEEP, PAIN, INTELLECTION, HYGIENE, AND DEATH. In one very handsome volume, royal 12mo. DANA (JAMES D). ZOOPHYTES AND CORALS. In one volume, imperial quarto, extra cloth, with wood-cuts. ALSO, AN ATLAS TO THE ABOVE, one volume, imperial folio, with sixty-one mag- nificent plates, colored after nature. Bound in half morocco. ALSO, ON THE STRUCTURE AND CLASSIFICATION OF ZOOPHYTES. Sold separate, one vol., cloth. DE LA BECHE (SIR HENRY T.), F. R. S., &c. THE GEOLOGICAL OBSERVER. In one very large and handsome octavo volume, of 700 pages. With over three hundred wood-cuts. (Lately Issued.) AND SCIENTIFIC PUBLICATIONS. 11 DRUITT (ROBERT), M.R. C.S., &c. THE PRINCIPLES AND PRACTICE OF MODERN SURGERY. A new American, from the 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. Dr. Druitt's researches into the literature of his subject have been not only extensive, but well di- rected ; the most discordant authors are fairly and impartially quoted, and, while due credit is given to each, their respective merits nre weighed with an unprejudiced hand. The grain of wheat is pre- served, and the chaff is unmercifully stripped off. The arrangement is simple and philosophical, and the style, though clear and interesting, is so precise, that the book contains more information condensed into a (ew words than any other surgical work with which we are acquainted.—London Medical Times and Gazelle, February 18, 1654. No work, in our opinion, equals it in presenting so much valuable surgical matter in so small a compass.—St. Louis Med. and Surgical Journal. Druitt's Surgery is too well known to the Ameri- can medical profession to require its announcement anywhere. Probably no work of the kind has ever been more cordially received and extensively circu- lated than this. The fact that it comprehends in a comparatively small compass, all the essential ele- ments of theoretical and practical Surgery—that it is found to contain reliable and authentic informa- tion on the nature and treatment of nearly all surgi- cal affections—is a sufficient reason for the liberal patronage it has obtained. The editor, Dr. F. W. Sargent, has contributed much to enhance the value of the work, by such American improvements as are calculated more perfectly to adapt it to our own views and practice in this country. It abounds everywhere with spirited and life-like illustrations, which to the young surgeon, especially, are of no minor consideration. Every medical man frequently needs just such a work as this, for immediate refe- rence in moments of sudden emergency, when he has not time to consult more elaborate treatises.—The Ohio Medical and Surgical Journal. The author hag evidently ransacked every stand- ard treatise of ancient and modern times, and all that is really practically useful at the bedside will be found in a form at once clear, distinct, and interest- ing.—Edinburgh Monthly Medical Journal. Druitt's work, condensed, systematic, lucid, and practical as it is, beyond most works on Surgery accessible to the American student, has had much currency in this country, and under its present au- spices promises to rise to yet higher favor.—The Western Journal of Medicine and Surgery. ' The most accurate and ample resume of the pre- sent state of Surgery that we areacquaintedwith.— Dublin Medical Journal. A better book on the principles and practice of Surgery as now understood in England and America, has not been given to the profession.—Boston Medi- cal and Surgical Journal. An unsurpassable compendium, not only of Sur- gical, but of Medical Practice.—London Medical Gazette. This work merits our warmest commendations, and we strongly recommend it to young surgeons as an admirable'digest of the principles and practice of modern Surgery.—Medical Gazette. It may be said with truth that the work of Mr. Druitt affords a complete, though brief and con- densed view, of the entire field of modern surgery. We know of no work on the same subject having the appearance of a manual, which includes so many topics of interest to the surgeon ; and the terse man- ner in which each has been treated evinces a most enviable quality of mind on the part of the author, who seems to have an innate power of searching out and grasping the leading facts and features of the most elaborate productions of the pen. It is a useful handbook for the practitioner, and we should deem a teacher of surgery unpardonable who did not recommend it to his pupils. In our own opinion, it is admirably adapted to the wants of the student.— Provincial Medical and Surgical Journal. DUNGLISON, FORBES, TWEEDIE, AND CONOLLY. THE CYCLOPEDIA OF PRACTICAL MEDICINE: comprising Treatises on the Nature and Treatment of Diseases, Materia Medica, and Therapeutics, Diseases of Women and Children, Medical Jurisprudence, &c. &c. In four large super royal octavo volumes, of 3254 double-columned pages, strongly and handsomely bound. *,(.* This work contains no less than four hundred and eighteen distinct treatises, contributed by sixty-eight distinguished physicians. unquestionably one of very great value to the prac- titioner. This estimate of it has not been formed from a hasty examination, but after an intimate ac- quaintance derived from frequent consultation of it during the past nine or ten years. The editors are practitioners of established reputation, and the list of contributors embraces many of the most eminent professors and teachers of London, Edinburgh, Dub- lin, and Glasgow. It is, indeed, the great merit of this work that the principal articles have been fur- nished 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 Journ. 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 prac- titioner.—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 of the profession in this country, it being DUNGLISON (ROBLEY), M.D., Professor of the Institutes of Medicine, in the Jefferson Medical College, Philadelphia. HUMAN HEALTH; or, the Influence of Atmosphere and Locality, Change of Air and Climate, Seasons, Food, Clothing, Bathing, Exercise, Sleep, &c. &c, on Healthy Man; constituting Elements of Hygiene. Second edition, with many modifications and additions. In one octavo volume, of 464 pages. 12 BLANCHARD & LEA'S MEDICAL DUNGLISON (ROBLEY), M.D., Professor of Institutes of Medicine in the Jefferson Medical College, Philadelphia. MEDICAL LEXICON; a Dictionary of Medical Science, containing a concise Explanation of the various Subjects and Terms of Physiology, Pathology, Hygiene, Therapeutics, Pharmacology, Obstetrics, Medical Jurisprudence, &c. With the French and other Synonymes; Notices of Climate and of celebrated Mineral Waters; Formulae for various Officinal, Empirical, and Dietetic Preparations, etc. Eleventh edition, revised. In one very thick octavo volume, of over nine hundred large double-columned pages, strpngly bound in leather, with raised bands. (Just Issued.) Every successive edition of this work bears the marks of the industry of the author, and of his determination to keep it fully on a level with the most advanced state of medical science. Thus nearly fifteen thousand words have been added to it within the last few years. As a complete Medical Dictionary, therefore, embracing over FIFTY THOUSAND DEFINITIONS, in all the branches of the science, it is presented as meriting a continuance of the great favor and popularity which have carried it, within no very long space of time, to an eleventh edition. Every precaution has been taken in the preparation of the present volume, to render its mecha- nical execution and typographical accuracy worthy of its extended reputation and universal use. The very extensive additions have been accommodated, without materially increasing the bulk of the volume by the employment of a small but exceedingly clear type, cast for this purpose. The press has been watched with great care, and every effort used to insure the verbal accuracy so ne- cessary to a work of this nature. The whole is printed on fine white paper ; and, while thus exhi- biting in every respect so great an improvement over former issues, it is presented at the original exceedingly low price. We welcome it cordially; it is an admirable work, and indispensable to all literary medical men. The labor which has been bestowed upon it is something prodigious. The work, however, has now been done, and we are hnppy in the thought that no hu- man being will have again to undertake the same gigantic task. Revised and corrected from time to time, Dr. Dunglison's "Medical Lexicon" will last for centuries.—British and Foreign Med. Chirurg. Review, July, 1853. The fact that this excellent and learned work has passed through eight editions, and that a ninth is rendered necessary by the demands of the public, affords a sufficient evidence of the general apprecia- tion of Dr. Dunglison's labors by the medical pro- fession in England and America. It is a book which will be of great service to the student, in teaching him the meaning of all the technical terms used in medicine, and will be of no less use to the practi- tioner who desires to keep himself on a level with the advance of medical science.—London Medical Times and Gazette. In taking leave of our author, we feel compelled to confess that his work bears evidence of almost incredible labor having been bestowed upon its com- position.— Edinburgh Journal of Med. Sciences, Sept. 1853. A miracle of labor and industry in one who has written able and voluminous works on nearly every branch of medical science. There could be no more useful hook to the student or practitioner, in the present advancing age, than one in which would be found, in addition to the ordinary meaning and deri- vation of medical terms—so many of which are of modern introduction—concise descriptions of their explanation and employment; and all this and much more is contained in the volume before us. It is therefore almost as indispensable to the other learned professions as to our own. In fact, to all who may have occasion to ascertain the meaning of any word belonging to the many branches of medicine. From a careful examination of the present edition, we can vouch for its accuracy, and for its being brought quite up to the date of publication ; the author states in his preface that he has added to it aboutfour thou- sand terms, which are not to be found in the prece- ding one. — Dublin Quarterly Journal of Medical Sciences. On the appearance of the last edition of this valuable work, we directed the attention of our readers to its peculiar merits; and we need do little more than state, in reference to the present reissue, that, notwithstanding the large additions previously made to it, no fewer than four thou- sand terms, not to be found in the preceding edi- tion, are contained in the volume before us.— Whilst it is a wonderful monument of its author's erudition and industry, it is also a work of great practical utility, as we can testify from our own experience; for we keep it constantly within our reach, and make very frequent reference to it, nearly always finding in it the information we seek. —British and Foreign Med.-Chirurg. Review. It has the rare merit that it certainly has no rival in the English language for accuracy and extent of references.- The terms generally include short physiological and pathological descriptions, so that, as the author justly observes, the reader does riot possess in this work a mere dictionary, but a book, which, while it instructs him in medical etymo- logy, furnishes him with a large amount of useful information. The author's labors have been pro- perly appreciated by his own countrymen ; and we can only confirm their judgment, by recommending this most useful volume to the notice of our cisat- lantic readers. No medical library will be complete without it__London Med. Gazette. It is certainly more complete and comprehensive than any with which we are acquainted in the English language. Few, in fact, could be found better qualified thun Dr. Dunglison for the produc- tion of such a work. Learned, industrious, per- severing, and accurate, he brings to the task all the peculiar talents necessary for its successful performance; while, at the same time, his fami- liarity with the writings of the ancient and modern " masters of our art," renders him skilful to note the exact usage of the several terms of science, and the various modifications which medical term- inology has undergone with the change of theo- ries or the progress of improvement. — American Journal of the Medical Sciences. One of the most complete and copious known to the cultivators of medical science.—Boston Med. Journal. The most comprehensive and best English Dic- tionary of medical terms extant.—Buffalo Medical Journal. BT THE SAME AUTHOR. THE PRACTICE OF MEDICINE. A Treatise on Special Pathology and The rapeutics. Third Edition. In two large octavo volumes, of fifteen hundred pages. Upon every topic embraced in the work the latest information will be found carefully posted up.— Medical Examiner. 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- we have.—Southern Med. and Surg. Journal ferings of the race—Boston Medical and Surgical Journal. It is certainly the most complete treatise of which we haveany knowledge.— Western Journal of Medi- cine and Surgery. One. of the most elaborate treatises of the kind AND SCIENTIFIC PUBLICATIONS. 13 DUNGLISON (ROBLEY), M.D., Professor of Institutes of Medicine in the Jefferson Medical College, Philadelphia. HUMAN PHYSIOLOGY. Seventh edition. Thoroughly revised and exten- sively modified and enlarged, with nearly five hundred illustrations. In two large and hand- somely printed octavo volumes, containing nearly 1450 pages. It has long since taken rank as one of the medi- j Physiology in the English language, and is highly eal classics of our language. To say that it is by j creditable to the author and publishers.—Canadian fur the best text-book of physiology ever published | Medical Journal. '- country, is but echoing the general testi- m tin mony of the profession.—N. Y. Journal of Medicine. • There is no single book we would recommend to the student or physician, with greater confidence than tin: present, because in it will be found a mir- ror of almost every standard physiological work of the day. We most cordially recommend the work to every member of the profession, and no student should be without it. It is the completest work on The most complete and satisfactory system of Physiology in the English language.—Amer. Med. Journal. The best work of the kind in the English lan- guage.—Silliman's Journal. The most full and complete system of Physiology in our language.—Western Lancet. BY THE SAME AUTHOR. (Just Issued.) GENERAL THERAPEUTICS AND MATERIA MEDICA; adapted for a Medical Text-book. Fifth edition, much improved. With one hundred and eighty-seven illus- trations. In two large and handsomely printed octavo vols., of about 1100 pages. The new editions of the United States Pharmacopoeia and those of London and Dublin, have ren- dered necessary a thorough revision of this work. In accomplishing this the author has spared no pains in rendering it a complete exponent of all that is new and reliable, both in the departments of Therapeutics and Materia Medica. The book has thus been somewhat enlarged, and a like ini provemeut will be found in every department of its mechanical execution. As a convenient text- book for the student, therefore, containing within a moderate compass a satisfactory resume of its important subject, it is again presented as even more worthy than heretofore of the very great favor which it has received. In this work of Dr. Dunglison, we recognize the same untiring industry in the collection and em- bodying of facts on the several subjects of which he treats, that has heretofore distinguished him, and we cheerfully,point to these volumes, as two of the most interesting that we know of. In noticing the additions to this, the fourth edition, there is very little in the periodical or annual literature of the profession, published in the interval which has elapsed since the issue of the first, that has escaped the careful search of the author. As a book for reference, it is invaluable.—Charleston Med. Jour- nal and Review. It may be said to be the work now upon the sub- jects upon which it treats.—Western Lancet. As a text-book for students, for whom it is par- ticularly designed, we know of none superior to it.—St. Louis Medical and Surgical Journal. It purports to be a new edition, but it is rather a new book, so greatly has it been improved, both in the amount and quality of the matter which it contains.—N. O. Medical and Surgical Journal. We bespeak for this edition, from the profession, an increase of patronage over any of its former ones, on account of its increased merit. — iV. Y. Journal of Medicine. We consider this work unequalled.—Boston Med. and Surg. Journal. BV THE SAME AUTHOR. NEW REMEDIES, WITH FORMULAE FOR THEIR ADMINISTRATION. Sixth edition, with extensive Additions. In one very large octavo volume, of over 750 pages. One of the most useful of the author's works.— Southern Medical and Surgical Journal. This well-known and standard book has now reached its sixth edition, and has been enlarged and improved by the introduction of all the recent gifts to therapeutics which the last few years have so richly produced, including the anaesthetic agents, &c. This elaborate and useful volume should be found in every medical library, for as a book of re- ference, for physicians, it is unsurpassed by any other work in existeuce, and the double index for diseases and for remedies, will be found greatly to enhance its value.—Xcw York Med. Gazette. The great learning of the author, and his remark- able industry in pushing his researches into every source whence information is derivable, has enabled him to throw together an extensive mass of facts and statements, accompanied by full reference to authorities; which lust feature renders the work practically valuable to investigators who desire to examine the original papers.—The American Journal of Pharmacy. DURLACHER (LEWIS). A TREATISE ON CORNS, BUNIONS, THE DISEASES OF NAILS, AND THE GENERAL MANAGEMENT OF THE FEET. pp. 134. In one 12mo. volume, cloth. DE JONGH (L. J.), M. D., &c. THE THREE KINDS OF COD-LIVER OIL, comparatively considered, with their Chemical and Therapeutic Properties. 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. DAY (GEORGE E.), M. D. A PR ACTICAL TREATISE ON THE DOMESTIC MANAGEMENT AND MORE IMPORTANT DISEASES OF ADVANCED LIFE. With an Appendix on a new and successful mode of treatiiij octavo, 2^0 pages. ; Lumbago and other forms of Chronic Rheumatism. One volume 14 BLANCHARD & LEA'S MEDICAL ELLIS (BENJAMIN), M.D. THE MEDICAL FORMULARY: being a Collection of Prescriptions, derived from the writings and practice of many of the most eminent physicians of America and Europe. Together with the usual Dietetic Preparations and Antidotes for Poisons. To which is added an Appendix, on the Endermic use of Medicines, and on the use of Ether and Chloroform. The whole accompanied with a few brief Pharmaceutic and Medical Observations. Tenth edition, revised and much extended bv Robert P. Thomas, M. D., Professor of Materia Medica in the Philadelphia College of Pharmacy. In one neal octavo volume, of two hundred and nmety-six pages. (Now Ready. Revised and enlarged to 1854.) This work has received a very complete revision at the hands of the editor, who has made what- ever alterations and additions the progress of medical and pharmaceutical^cience has rendered ad visable. introducing fully the new remedial agents, and revising the whole by the latest improvements of the Pharmacopoeia. To accommodate these additions, the size of the page has been increased, and the volume itself considerably enlarged, while every effort has been made to secure the typo- graphical accuracy which has so long merited the confidence of tbe profession. After an examination of the new matter and the It will prove particularly useful to students and alterations, we believe the reputation of the work yonng practitioners, as the most important presenp- built up by the author, and the late distinguished tions employed in modern practice, which lie scat- editor, will continue to nourish under the auspices tered through our medical literature, are here col- of the present editor, who has the industry and accu- lected and conveniently arranged for reference.— racy, and, we would say, conscientiousness requi- Charleston Med. Journal and Review. site for the responsible task.—American Journal of Pharmacy, March, 1854. ERICHSEN (JOHN)., Professor of Surgery in University College, London, &.C. THE SCIENCE AND ART OF SURGERY; being a Treatise on Surgical Injuries, Diseases, and Operations. With Notes and Additions by the American Editor. Il- lustrated with over three hundred engravings on wood. In one large and handsome octavo volume, of nearly nine hundred closely printed pages. (NowReady.) This is a new work, brought up to May, 1854. This work, which is designed as a text-book for the student and practilioner, will be found a very complete treatise on the principles and practice of surgery. Embracing both these branches of the subject simultaneously, and elucidating the one by the other, it enables the reader to take a compre- hensive view of the objects of his study, and presents the subjects discussed in a clear and con- nected manner. The author's style will be found easy and flowing, and the illustrations having been drawn under his especial supervision, are with few exceptions new, and admirably adapted to elucidate the text to which they refer. In every point of mechanical execution, it will be one of the handsomest works issued from the American press The aim of Mr. Erichsen appears to be to improve upon the plan of Samuel Cooper; and by connecting in one volume the science and art of Surgery, to' supply the student with a text-book and the practi- tioner with a work of reference, in which scientific principles and practical details are alike included. We may say, afier a careful perusal of some of the chapters, and a more hasty examination of the remainder, that it must raise the character of the author, and reflect great credit upon the College to which he is Professor, and we can cordially recom- mend it as a work of reference, both to students and practitioners.—Medical Times and Gazette. " We do not hesitate to say that the volume before us gives a very admirable practical view of the sci- ence and art of surgery of the present day, and we have no doubt that it will be highly valued as a sur- gical guide as well by the surgeon as by the student of surgery.—Edinburgh Med. and Surg. Journal. FERGUSSON (WILLIAM), F. R. S., Professor of Surgery in King's College, London, &c. A SYSTEM OF PRACTICAL SURGERY. Fourth American, from the third and enlarged London edition. In one large and beautifully printed octavo volume, of about seven hundred pages, with three hundred and ninety-three handsome illustrations. (Just Issued.) The most important subjects in connection with practical surgery which have been more recently brought under the notice of, and discussed by, the surgeons of Great Britain, are fully and dispassion- ately considered by Mr. Fergusson, and that which was before wanting has now been supplied, so that we can now look upon it as a work on practical sur- gery instead of one on operative surgery alone. And we think the author has shown a wise discretion in making the additions on surgical disease which are to be found in the present volume, and has very much enhanced its value; for, besides two elaborate chapters on the diseases of bones and joints, which were wanting before, he has headed each chief sec- tion of the work by a general description of the sur- gical disease and injury of that region of the body which is treated of in each, prior to entering into the consideration of the more special morbid conditions and their treatment. There is also, as in former editions, a sketch of the anatomy of particular re- gions There was some ground formerly for the complaint before alluded to, that it dwelt too exclu- sively on operative Surgery ; but this defect is now removed, and the book is more than ever adapted for the purposes of the practitioner, whether he confines himself more strictly to the operative department, or follows surgery on a more comprehensive scale.— Medical Times and Gazette. No work was ever written which more nearly comprehended the necessities of the student and practitioner, and was more carefully arranged to that single purpose than this.—N. Y. Med. and Surg. Journal. The addition of many new pages makes this work more than ever indispensable to the student and prac- titioner.—Ranking's Abstract. Among the numerous works upon surgery pub- lished of late years, we know of none we value more highly than the one before us. It is perhaps the very best we have for a text-book and for ordi- nary reference, being concise and eminently practi- cal.—Southern Med. and Surg. Journal. FRICK (CHARLES), M. D. RENAL AFFECTIONS; their Diagnosis and Pathology. One volume, royal 12mo., extra cloth. With illustrations. AND SCIENTIFIC PUBLICATIONS. 15 FOWNES (GEORGE), PH. D., &c. ELEMENTARY CHEMISTRY; Theoretical and Practical. With numerous illustrations. A new American, from the last and revised London edition. Edited, with Addi- tions, by Robert Bridges, M. D. In one large royal 12mo. volume, of over 550 pages, with 181 wi 'od-cuts, sheep, or extra cloth. (Now Ready.) The lamented death of the author has caused the revision of this edition to pass into the hands of Jnose distinguished chemists, H. Bence Jones and A. W. Hoimann, who have fully sustained its reputation by the additions which they have made, more especially in the portion devoted to Organic Chemistry, considerably increasing the size of the volume. This labor has been so thoroughly performed, that the American Editor has found but little to add, his notes consisting chiefly of such matters as the rapid advance of the science has rendered necessary, or of investigations which had apparently been overlooked by the author's friends. The volume is therefore again presented as an exponent of the most advanced slate of chemical science, and as not unworthy a continuation of the marked favor which it has received as an ele- mentary text-book. We know of no better text-book, especially in the difficult department of organic chemistry, upon which it is particularly full and satisfactory. We would recommend it to preceptors as a capital " office book" for their students who are beginners in Chemistry. It is copiously illustrated with ex- cellent wood-cuts, and altogether admirably " got up."—X J. Medical Reporter, March, 1854. A standard manual, which has long enjoyed the reputation of embodying much knowledge in a small space. The author hasachieved the difficult task of condensation with masterly tact. His book is con- cise without being dry, and brief without being too dogmatical or general.— Virginia Med. and Surgical Journal. The work of Dr. Fnwr.es has long been before the public, and its merits have been fully appreci- ated as the best text-book on chemistry now in existence. We do not, of course, place it in a rank superior to the works of Brunde, Graham, Turner, Gregory, or Gmelin, but we say that, as a work for students, it is preferable to any of them.—Lon- don Journal of Medicine. A work well adapted to the wants of the student. It is an excellent exposition of the chief doctrines and facts of modern chemistry. The size of the work. and still more the condensed yet perspicuous style in which it is written, absolve it from the charges very properly ur-jed against most manuals termed popular.—Edinburgh Monthly Journal of Meiical Science. GRAHAM (THOMAS), F.R.S., Professor of Chemistry in University College, London, &c. THE ELEMENTS OF CHEMISTRY. Including the application of the Science to the Arts. With numerous illustrations. With Notes and Additions, by Robert Bridges, M. D., &c. &c. Second American, from the second and enlarged London edition PART I. (Lately Issued) large 8vo., 430 pages, 185 illustrations. PART II. (Preparing) to match. The great changes which the science of chemistry has undergone within the last few years, ren- der a new edition of a treatise like the present, almost a new work. The author has devoted several years to the revision of his treatise, and has endeavored to embody in it every fact and inference of importance which has been observed and recorded by the great body of chemical investigators who are so rapidly changing the face of the science. In this manner the work has been greatly increased in size, and the number of illustrations doubled ; while the labors of the editor have been directed towards the introduction of such matters as have escaped the attention of the author, or as have arisen since the publication of the first portion of this edition in London, in IS-'iO. Printed in handsome style, and at a very low price, it is therefore confidently presented to the pro- fession and the student as a very complete and thorough text-book of this important subject. GROSS (SAMUEL D.), M. D., Professor of Surgery in the Louisville Medical Institute, &c. A PRACTICAL TREATISE ON THE DISEASES AND INJURIES OF THE URINARY ORGANS. In one large and beautifully printed octavo volume, of over seven hundred pages. With numerous illustrations. A volume replete with truths and principles of the utmost value in the investigation of these diseases.— American Medical Journal. Dr. Gross has brought all his learning, experi- ence, tact, and judgment to the task, and has pro- duced a work worthy of his high reputation. We feel perfectly safe in recommending it to our read- ers as a monograph unequalled in interest and practicnl value by any other on the subject in our language.—Western Journal of Med. and Surg. It has remained for an American writer to wipe away this reproach ; and so completely has the task been fulfilled, that we venture to predict for Dr. Gross's treatise a permanent place in the literature of surgery, worthy to rank with the best works of the present age. Not merely is the matter good, this department of art. We have, indeed, unfeigned pleasure in congratulating all concerned in this pub- lication, on the result of their labours; and expe- rience a feeling something like what animates a long- expectant husbandman, who, often times disappointed by the produce of a favorite field, is at last agree- ably surprised by a stalely crop which may bear comparison with any of its former rivals. The grounds of our high appreciation of the work will be obvious as we proceed; and we doubt not that the present facilities for obtaining American books will induce many of our readers to verify our re- commendation by their own perusal of it.—British and Foreign Medico-Chirurgical Review. Whoever will peruse the vast amount of valuable practical information it contains, and which we but the getting up of the volume is most creditable | have been unable even to notice, will, we think, to transatlantic enterprise; the paper and print agree with us, that there is no work in the English would do credit toa first-rate London establishment; language which can make any just pretensions to and the numerous wood-cuts which illustrate it, de- ' be its equal.—N. Y. Journal of Medicine. monstrale that America is making rapid advances in | by the same author. (In Press.) A PRACTICAL TREATISE ON FOREIGN BODIES IN THE AIR-PAS- SAGES. In one handsome octavo volume, with illustrations. BY THE same author. (Preparing.) A SYSTEM OF SURGERY; Diagnostic, Pathological, Therapeutic, and Opera- tive. With very numerous engravings on wood. 16 BLANCHARD & LEA'S MEDICAL GLUGE (GOTTLIEB), M.D., Professor of Physiology and Pathological Anatomy in the University of Brussels, &c. AN ATLAS OF PATHOLOGICAL HISTOLOGY. Translated, with Notes and Additions, by Joseph Leidy, M. D., Professor of Anatomy in the University of Pennsylva- nia. In one volume, very large imperial quarto, with three hundred and twenty figures, plain and colored, on twelve copperplates. This being, as far as we know, the only work in which pathological histology is separately treated of in a comprehensive manner, it will, we think, for this reason, be of infinite service to those who desire to investigate the subject systematically, and who have felt the difficulty of arranging in their mind the unconnected observations of a great number of authors. The development of the morbid tissues, and the formation of abnormal products, may now be followed and studied with the same ease and satisfaction as the best arranged system of phy- siology.—American Med. Journal. GRIFFITH (ROBERT E.)f M. D., &.C. A UNIVERSAL FORMULARY, containing the methods of Preparing and Ad- ministering Officinal and other Medicines. The whole adapted to Physicians and Pharmaceu- tists. Second Edition, thoroughly revised, with numerous additions, by Robert P. Thomas, M. D., Professor of Materia Medica in the Philadelphia College of Pharmacy. In one large and handsome octavo volume, of over six hundred pages, double columns. (Just Ready.) The speedy exhaustion of a large edition, and the demand for a second, sufficiently show the posi- tion which this work has so rapidly attained as an authoritative and convenient work of reference for the physician and pharmaceutist. The opportunity thus afforded for its improvement has not been neglected. In its revision, Professor Thomas (to whom this task has been confided in consequence of the death of the author), has spared no labor, in the hope of rendering it the most complete and correct work on the subject as yet presented to the profession. All the newly introduced articles of the Materia Medica have been inserted, such formulae as had escaped the attention of Ihe author have been added, and the whole has been most carefully read and examined, to insure the absolute correctness, so indispensable in a work of this nature. The amount of these additions may be esti- mated from the fact that not only has the page been considerably enlarged, but the volume has also been increased by about fifty pages, while the arrangement of the formulae and the general typo- graphical execution will be found to have undergone great improvement. To the practitioner, its copious collection of all the forms and combinations of the articles of the Pharmacopoeia render it an invaluable book of reference, while its very complete embodiment of officinal preparations of all kinds, derived from all sources, American, English, and Continental, make it an indispensable assist- tant to the apothecary. Dr. Griffith's Formulary is worthy of recommen- dation, not only on account of the care which has been bestowed on it by its estimable author, but. for its general accuracy, and the richness of its details. —Medical Examiner. Most cordially we recommend this Universal Formulary, not forgetting its adaptation to drug- gists and apothecaries, who would find themselves vastly improved by a familiar acquaintance with this every-day book of medicine.—The Boston Med. and Surg. Journal. A very useful work, and a most complete compen- dium on the subject of materia medica. AVe know of no work in our lang-uage, or any other, so com- prehensive in all its details.—London Lancet. Pre-eminent among the best and most useful com- pilations of the present day will be found the work before us, which can have been produced only at a very great cost of thought and labor. A short de scription will suffice to show that we do not put too high an estimate on this work. We are not cog- nizant of the existence of a parallel work. Its value will be apparent to our readers from the sketch of its contents above given. We strongly recommend it to all 'who are engaged either in practical medi- cine, or more exclusively with its literature.—Lond. Med. Gazette. A valuable acquisition to the medical practitioner, and a useful book of reference to the apothecary on numerous occasions.—Amer. Journal of Pharmacy. BY THE SAME AUTHOR. MEDICAL BOTANY; or, a Description of all the more important Plants used in Medicine, and of their Properties, Uses, and Modes of Administration. In one large octavo volume, of 704 pages, handsomely printed, with nearly 350 illustrations on wood. One of the greatest acquisitions to American medi- cal 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.—South-western Medical Advocate. Admirably calculated for the physician and stu- dent — we have seen no work which promises greater advantages to the profession.—N. O. Med. and Surg. Journal. One of the few books which supply a positive de- ficiency 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 li- brary of every private practitioner.—^V. Y. Journal of Medicine. GREGORY (WILLIAM), F. R. S. E., Professor of Chemistry in the University of Edinburgh, &c. LETTERS TO A CANDID INQUIRER ON ANIMAL Description and Analysis of the Phenomena. Details of Facts and Cases. royal 12mo., extra cloth. GARDNER (D. PEREIRA), M. D. MAGNETISM. In one neat volume, AND SCIENTIFIC PUBLICATIONS. 17 HASSE (C. E.), M. D. AN ANATOMICAL DESCRIPTION OF THE DISEASES OF RESPIRA- TION AND CIRCULATION. Translated and Edited by Swaine. In one volume, octavo. HARRISON (JOHN), M.D. AN ESSAY TOWARDS A CORRECT THEORY OF THE NERVOUS SYSTEM. In one octavo volume, 292 pages. HUNTER (JOHN). TREATISE ON THE VENEREAL DISEASE. With copious Additions, by Dr. Ph. Ricord, Surgeon to the Venereal Hospital of Paris. Edited, with additional Notes, by F. J. Bumstead, M. D. In one octavo volume, with plates (Now Ready.) EF* See Ricord. Also, HUNTER'S COMPLETE WORKS, with Memoir, Notes, &c. &c. In four neat octavo volumes, with plates. HUGHES (H. M.), M. D.f Assistant Physician to Guy's Hospital, &c. A CLINICAL INTRODUCTION TO THE PRACTICE OF AUSCULTA- TION, and other Modes of Physical Diagnosis, in Diseases of the Lungs and Heart. Second American from the Second and Improved London Edition. In one royal ]2mo. vol. (Just Ready.) It has been carefully revised throughout. Some small portions have been erased; much has been, I trust, amended; and a great deal of new matter has been added; so that, though funda- mentally it is the same book, it is in many respects a new work.—Preface. HORNER (WILLIAM E.), M. D., Professor of Anatomy in the University of Pennsylvania. SPECIAL ANATOMY AND HISTOLOGY. Eighth edition. Extensively revised and modified. In two large octavo volumes, of more than one thousand pages, hand- somely printed, with over three hundred illustrations. This work has enjoyed a thorough and laborious revision on the part of the author, with the view of bringing it fully up to the existing state of knowledge on the subject of general and special anatomy. To adapt it more perfectly to the wants of the student, he has introduced a large number of additional wood-engravings, illustrative of the objects described, while the publishers have en- deavored to render the mechanical execution of the work worthy of the extended reputation which it has acquired. The demand which has carried it to an EIGHTH EDITION is a sufficient evi- dence of the value of the work, and of its adaptation to the wants of the student and professional reader. HOBLYN (RICHARD D.), A. M. A DICTIONARY OF THE TERMS USED IN MEDICINE AND THE COLLATERAL SCIENCES. Second and Improved American Edition. Revised, with nu- merous Additions, from the second London edition, by Isaac Hays, M. D., &c. In one large royal 12mo. volume, of over four hundred pages, double columns. (Nearly Ready.) In passing this work a second time through the press, the editor has subjected it to a very tho- rough revision, making such additions as the progress of science has rendered desirable, and sup- plying any omissions that may have previously existed. As a concise and convenient Dictionary of Medical Terms, at an exceedingly low price, it will therefore be found of great value to the stu- dent and practitioner. HOPE (J.), M. D., F. R. S., &c. A TREATISE ON THE DISEASES OF THE HEART AND GREAT VESSELS. Edited by Pennock. In one volume, octavo, with plates, 572 pages. HERSCHEL (SIR JOHN F. W.), F. R. S., &.c. OUTLINES OF ASTRONOMY. New American, from the third London edition. In one neat volume, crown octavo, with six plates and numerous wood-cuts. (Just Issued.) HUMBOLDT (ALEXANDER). ASPECTS OF NATURE IN DIFFERENT LANDS AND DIFFERENT CLIMATES. Second American edition, one vol. royal 12mo., extra cloth. JONES (T. WHARTON), F. R. S., See. THE PRINCIPLES AND PRACTICE OF OPHTHALMIC MEDICINE AND SURGERY. Edited by Isaac Hays, M. D., ips. (Just issued.) JOHNSTON'S ATLAS OF PHYSICAL GEOGRA- PHY. 1 vol., with 20 colored plates, hf. bound. LARDNER'S HANDBOOKS OF NATURAL PHI- LOSOPHY AND ASTRONOMY. First Course, containing Mechanics, Hydrosta- tics, Hydraulics, Pneumatics, Sound, and Optics. 1 very large vol., royal 12mo., sheep, 424 cuts. Second Course, containing Heat, Electricity, Mag- netism, and Galvanism. 1 vol. royal 12mo.,sheep, 250 cuts. Third Course, containing Astronomy and Meteo- rology. 1 very large vol., royal 12mo., 37 plates and 216 wood-cuts. (Now ready.) MULLER'S PHYSICS AND METEOROLOGY. 1 vol. 8vo., over 500 beautiful cuts and two colored plates, extra cloth. NATIONAL SCHOOL MANUAL. 4 pans. 12mo. ORR'S PHYSIOLOGY OF ANIMAL AND VEGE- TABLE LIFE. A new and popular work. lvol. royal 12mo. with illustrations. (Just Ready.) 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Gentlemen who receive this, and Postmasters, are requested to forward us, by mail, lists of the physicians and principals of academies in their counties. For all such lists, received free of postage, we will in return send a copy of "Carpenter on the Use and Abuse of Alco- holic Liquors," done up in flexible cloth, postage paid. BLANCHARD & LEA, Philadelphia. * tt': i I— ^-......-■; /■