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E. HORNER, M. D. ADJUNCT PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA, ONE OF THE SURGEONS OF THE PHILADELPHIA ALMS-HOUSE, &C. PHILADELPHIA: PUBLISHED BY EDWARD PARKER. WiUiam Brown, Printer, 1823. ISB3 Eastern District of Pennsylvania, to -wit : BE IT REMEMBERED, That on the twenty-sixth day of June, in the forty-seventh year of the Independence of the United States of America, A. D. 1823, William E. Horner, M. D. of the said district, hath deposited in this office the title of a book the right whereof he claims as author in the words following, to wit: " Lessons in Practical Anatomy, for the use of Dissectors. By W. E. Hor- ner, M. D. Adjunct Professor of Anatomy in the University of Pennsylva- nia, one of the Surgeons of the Philadelphia Aims-House, &c." In conformity to the act of the Congress of the United States, intitled, " An act for the encouragement of learning, by securing the copies of maps, charts, and books, to the authors and proprietors of such copies, during the times therein mentioned;"—and also to the act, entitled, " An act supple- mentary to an act, entitled,' An act for the encouragement of learning, by securing the copies of maps, charts, and books, to the authors and proprie- tors of such copies during the times therein mentioned,' and extending the benefits thereof to the arts of designing, engraving, and etching historical and other prints." D. CALDWELL, Clerk of the Eastern District of Pennsylvania, TO PHILTP S. PHYSICK, M. D. PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA. Dear Sir, Permit me to dedicate to you this little work, proceeding from a course of Anatomical Studies in which your patronage has been incessantly active, and which, without your disinterested protection and encouragement, might probably have long since been relinquished. I consider it a feeble and insufficient testimony of the large debt of gratitude that I owe you, and wish that it was more'worthy of your notice; how- ever, as it is the best at present in my power, I hope that it will be accepted in the sense in which it is offer- ed. That a life so usefully employed as yours in miti- gating the ills of human existence, and in enlarging the boundaries of the science of medicine, may be protracted through a long series of years with undi- minished physical and mental vigour, is the sincere prayer of, Dear Sir, Your Obedient Servant, W. E. HORNER Philadelphia, July 1, 1823. CONTENTS. Pase Preface,............... v" Introduction—On Dissecting, and on the method of mak- ing Anatomical Preparations,.......xv PART I. Of the Head and Neck,.......... 1 Chap. I. External Parts of the Head and Neck, ... 1 Sect. I. Of the Muscles and Fasciae of the Head and Neck,......... 2 II. Of the Glands of the Head and Neck, . 23 III. Of the Blood-vessels of the Neck and Head,..........29 IV. Of the Nerves of the Head and Neck, . 38 Chap. II. Of the Internal Parts of the Head and Neck, . 51 Sect. I Of the Brain and Spinal Marrow, ... 51 II. Of the Brain and Spinal Marrow accord- ing to Gall and Sfurzheim, ... 77 III. Of the Eye,......... 112 IV. Of the Ear,.........129 V. Of the Nose,.........142 VI Of the Mouth,........146 VII. Of the Pharynx and (Esophagus, . . 151 VIII. Of the Larynx,.......154 PART II. Of the Trunk,.............'64 Chap. I. Of the Thorax,..........164 Sect. I. Of the Muscles in front, and on the sides of the Thorax,.......164 II. Of the Viscera of the Thorax, .... 168 Chap. II. Of the Abdomen,.........191 Sect. I- Of the Muscles of the Abdomen, ... 192 II'. Of the Parts concerned in Inguinal Hernia, 203 vi CONTENTS. Page Sect. HI. Of the Parts concerned in Femoral Hernia, 211 IV. Of the Contents of the Abdomen, . . 221 V. Of the Diaphragm,.......255 Chap. III. Of the Male Pelvis,........261 Sect. I. Of the Viscera of the Male Pelvis, . . 262 II. Of the Perineum and the Fasciae of the Male Pelvis,........282 Chap. IV. Of the Organs in the Female, for the Genera- tion and Nourishment of the Infant, . . 296 Sect. I. Of the Female Pelvis,......296 II. Of the Female Mammas,.....310 Chap. V. Of the Nerves and Vessels of the Trunk, . . 315 Sect. I. Of the Nerves,........315 II. Of the Blood-vessels,......325 III Of the Thoracic Duct,.....338 Chap. VI. Of the Muscles of the Back,......340 PART III. Of the Extremities and Ligaments,......355 Chap. I. Of the Upper Extremities,.......355 Sect. I. II. HI. Of the Fascia and Muscles, . . 355 IV. Of the Blood-vessels,......385 V. Of the Nerves,........400 Chap. II. Of the Lower Exiremities,......408 Sect. I. Of the Fascia and Muscles, .... 408 II. Of the Blood-vessels,......445 III. Of the Nerves,........459 Chap. III. Of the Ligaments,.........471 Sect. I Ligaments of Head and Spine, . . . 471 II. Ligaments of Thorax,......475 III. Ligaments of Pelvis,......477 IV. Ligaments of the Upper Extremities, . 480 V. Ligaments of the Inferior Extremities, . 487 Of the Skin,..............495 Hair,..............498 Nails,..............499 Sebaceous Organs,..........499 Index,................501 PREFACE. The following sheets were put together with a hope of their contributing, in some measure, to facilitate the most difficult and important part of a medical education, the study of Anatomy. They are the result of many dissections performed in the course of ten years by myself, and by the young men who have con- fided in me by submitting to my instructions. The arrangement is in some respects unusual, as regards a work on Practical Anatomy; but has arisen from much reflection on the subject, and from a careful observation of that course which students are most disposed to adopt when left to themselves. There are but few men possessed of moderate activity of mind who do not, in the prosecution of a study even new to them, adopt some labour-saving means, overlooked and sometimes unknown, to such as are much further advanced. It has happened to me frequently, while su- perintending the studies of others, to observe this fact, viii PREFACE. and that none of the books in common use answered continually as objects of reference; either in conse- quence of the actual plan of the books not being suitable to the course of dissections, or in consequence of the partition of the subject among several students causing the dissection of one person to interfere with that of another. The idea of founding a text-book on corresponding arrangements, was derived from this source; and I trust therefore that it will, in most cases, be found to answer either where several students dis- sect together on the same subject, or where the stu- dent dissects alone upon a section of the body. In the original conception of the work it appeared to me that I might introduce advantageously remarks on Morbid Anatomy, on Surgical Operations, and on Physiology; but in computing the number of pages that the descriptive anatomy alone would occupy, I found that such latitude of materials would convert it into a system, and interfere much with the simplicity and conciseness that I wished should predominate in the character of the performance. I have therefore intentionally indulged very seldom in such remarks; but in case of J;he present effort meeting the sanction PREFACE. ix of public approbation, may be tempted at a future day to give an additional volume appropriated to these subjects. As the introduction of such observations is very common in manuals of Anatomy, I will state other objections to my pursuing the usual course. \n my own progress as a student, I had a hand-book of this kind, but it very frequently happened that the subject that I was engaged in dissecting, had none of the diseases or morbid appearances with which the page that I was reading referred to. The author in- deed seemed to labour under the presumption that the young anatomist was working on just such a subject as he had in view, and therefore blended his morbid and descriptive anatomy so much by alternate sen- tences for each, and sometimes in the same sentence, that the eye could not, without much trouble, disen- tangle the two. A positive inconvenience was thus sustained. In regard to surgical operations, the young student seldom performs them in his first period of dissections; his mind is closely and laboriously oc- cupied in pursuing the dissection, in getting out the parts properly, and he thinks he has quite enough to do in following the most simple description. As b x PREFACE. regards physiology, the reasons just stated must appiy with more force to it. I do not wish to be understood as giving a diminished importance to Morbid Ana- tomy, on the contrary, I have the highest opinion of its value, as the whole practice of medicine is founded on it; I mean only that a text-book for young stu- dents should present the task of Anatomy in its most simplified form. When the parts become familiar and well understood by frequent dissection, the ad- vanced student may then draw in as many collateral branches as he chooses, and he will never attempt it without pleasure and instruction. At this point any of the treatises on surgery and morbid anatomy will answer his pur, ose. I have been concise on another subject: Directions how to proceed, to which some Anatomists give the highest importance, so high indeed that in many in- stances the subject matter is lost in the directions how it is to be found out. In the opinions of some, I may here have fallen into error: my general intention has been, in all cases, to assist by directions where the novelty and obscurity of the operation left no clue for the student; but where the dissection or mode of ex- PREFACE. Xi animation was a plain appeal to common sense, con- nected with common powers of vision, I have thought it superfluous, and even ridiculous to write down what was to be done. In the common operation of walk- ing, it would be quite philosophical to tell a being of another world, who knew nothing of this, and was differently constituted, that it was accomplished by putting one leg before the other; but perhaps there is no human being, in the rational exercise of his facul- ties, who would thank any one for such information. On this ground I have omitted many directions; but it is not improbable that things which seem perfectly plain and appreciable to one in the daily exercise of Anatomy, may be more obscure to another in differ- ent circumstances. It will be seen that the work consists of three Parts; the Head and Neck, with the contained organs, form one part, the Trunk a second, and the Extremities a third. The division is obviously artificial, as probably every other plan must be; for in following the details of Anatomy, it is impossible to avoid chasms in the description. The human body is a whole, but made up of such a multitude of parts that no mind can com- Xii PREFACE. prehend or receive at once all of them. In this di- lemma, each writer will probably have an arrange- ment, which to him, appears better than all others. It may be asked, why I have put the most difficult part of Anatomy first? I answer, that it is only first to him who chooses to study it as such. The plan of the book enables the student to commence >vith either of the parts, with nearly equal advantage. In adopting this plan, the most prominent objection in my mind to it, was the necessity of repeating the same observations in different places. In writing I have had this continually in view; and though it could not always be avoided, I have nevertheless endeavoured to curtail so much its frequency, that, I trust, it will not be considered a fault of much magnitude. In regard to recent observations in Anatomy, I have for the most part quoted them when they were of such a cast as to be comprehended in the general ob- ject of the work. I have also added a few new things of an original character with myself; they consist prin- cipally in a muscle at the inner canthus of the eye, not heretofore described, and in an explanation of the method of closing the upper part of the glottis in PREFACE. xiil swallowing or vomiting, not commonly alluded to by physiologists. It may be asked why, with such a quantity of simi- lar works in circulation, I have taken the trouble to write this? I reply candidly, because I think their plans and manner of execution do not hit precisely the case for which they are intended. I have however neither the disposition nor intention to decry them, because my own ware is in the market. I have felt much their value in many respects, and take pleasure in giving my feeble tribute of praise to the works of Messrs. Fyfe, Bell, Shaw, and the London Dissector, among the English; and to the works of M M. Mar- jolin and Maygrier, among the French. On the sub- ject of Hernia, I am much indebted to Sir Astley Cooper and to Mr. Laurence. On the Anatomy of the Pelvis, to Messrs. Colles and Breschet. Among the Systematic Treatises of Anatomy, I owe much to Dr. Wistar's System, to Bichat, Sabatier, Portal, Bell, and above all to the very splendid and surpass- ing work of Antonius and Caldani published in Ve- nice, which contains all things excellent in our art, selected from Soemmering, Loder, Meckel, Scarpa, xiv PREFACE. Vicq. D'Azyr, the Hunters, Gall and Spurzheim, & &c, which was put into my hands by the liberality Dr. Physick. INTRODUCTION. On Dissecting, and on Anatomical Preparations.-. The dress of a student of anatomy should consist of an apron, extending from the neck to half-way down the legs, and of a pair of sleeves, attached to the apron or not, according to the fancy of the wearer. It should be so loose as to give him perfect facility in all his motions. The instruments are contained in a box called a Dissecting Case. They should consist of four knives, one single hook, one double hook, one pair of forceps, one pair of scissors, one blow pipe, and two crooked needles. Cleanliness is of the first importance; the dissector should, therefore, never suffer his table to become foul from blood or pieces of flesh standing on it, neither should he suffer blood to remain in the differ- ent depressions about the subject where it can be conveniently got out. He should keep a sponge for himself, for where a sponge is used by several it be- comes nobody's business to clean it; the consequence is that it is seldom fit for use. When the integuments of a subject are laid open, the parts exposed either Xvi INTRODUCTION dry or putrefy rapidly. A constant rule is hence esta- blished not to turn down more skin than there is oc- casion for, and to save it as much as possible in order to cover the parts again, when the dissection is sus- pended for an interval. When there is not enough of it for this purpose, a damp linen cloth several folds thick should be at hand to assist in covering. The knife should be held like a writing pen in the right hand; when muscles are dissected it should be exclusively used for cutting, as the scissors do not an- swer. The integuments or the parts covering the muscles should be held perfectly tense with the other hand or with the forceps. The knife should be pass- ed with a steady and light stroke in the direction of the muscular fibres, and in such a way as just to graze them. This latter rule is indispensable; no one can dissect a muscle well without observing it, and it should be continually present to the mind of the stu- dent. OF INJECTIONS. There are three kinds of injections in use among anatomists, the Course, the Fine, and the Minute; which are applied to the filling of the arteries and the veins in order to demonstrate their courses more sa- tisfactorily. INTRODUCTION. xvii No. I. For Course injection take the following propor- tions: Yellow Bees-wax, pure, sixteen ounces, Bleached Rosin, eight ounces, Turpentine Varnish, by measure, six ounces. Mix and liquefy them over a slow fire, or, what is still better, in boiling water. For making this mixture red; add Vermilion, §iij. do. do. yellow; King's Yellow, Jijss. do. do. white; Best Flake White, gvss. rBest Flake White, ^iijss. do. do. pale blue; | ^ filue ^^ ^ do. do. dark blue; Blue Verditer, ^xss. do. do. black; Lamp-Black, §i. ( Powdered Verdigris, ^ivss. do. do. green; 1 Best Flake White, |iss. ( Gamboge, powdered, ^i, No. II. For Fine injection take the following proportions: Brown Spirit Varnish, ^iv. White Spirit Varnish, |iv. Turpentine Varnish, ^i. Mix and heat xviii INTRODUCTION. To make this mixture red; add Vermilion, ^i. do. do yellow; Kings Yellow, §ii: do. do. white; Best Flake White, §ij. rFine Blue Smalt, ^iss. do. do. - light blue; J Be3tFlakeWhite,|ii. do. do. dark blue; Blue Verditer, ^iv. do. do. black; Lamp-Black, 5ss. No. III. For Minute injection take the following propor- tions: Most Transparent Glue broken to pieces, ^viij. Water, Ibiss. Mix. Let the mixture stand till the glue is dissolved, which will take from one to two days. Then heat it gently till the mixture is uniform, or a perfect size is made. To make this mixture red; add Vermilion, 5v. Kings Yellow, 5iv. Best Flake White, gv. Fine Blue Smalt, iviij. C Powdered Verdigris, 5iij. do. do. green; 1 Best Flake White, 31J. ^ Gamboge powdered, gij. do. do. black; Lamp-Black, 5i. In all of these formulas for injections, it is of the utmost importance to success in throwing them in to do. do. yellow; do. do. white; do. do. blue; INTRODUCTION. xix have the colours in the purest condition and reduced to the finest powder by levigation or trituration. In Philadelphia they are found, for the most part, in a state fit for use in the Druggist's, and Painter's and Glazier's shops. But to render injection still more certain it is better to strain the mixtures after the co- lours are added, through a fine flannel cloth, which arrests the impurities both in the original mixture and in the colouring ingredients. No. IV. A commodious injection, and, for the most part, a very successful one. has been in use amongst us for many years. It is also much approved, I have un- derstood, in other parts of the United States. It is commonly called the Cold Injection. To make it, take White Lead and Red Lead, of each ^iv. Linseed Oil enough to form a thick paste by rubbing them well together. Liquefy this paste with Turpentine Varnish, viii. Just before injecting sprinkle this mixture with cold water, which disposes it to set or coagulate. The advantage of it is, that it does not require the subjec to be previously heated. The colour may be improv- ed with vermilion. xx INTRODUCTION. White Lead, treated in the same way with linseed oil and turpentine varnish, may have its colour chang- ed to fancy by any of the colouring matters mention- ed. It is not necessary to strain these lead mixtures. No. V. When the student wishes only to prosecute the dissection of the vessels without making a preparation of them, the following injection will answer. Tallow, ffcij. Turpentine Varnish, ^x. Red Lead, !VUJ- Mix. This mixture retains its fluidity, when melted, for a long time, and may be thrown from the arch of the aorta through the primitive and many of the secon- dary arterial trunks without heating the subject. Its cheapness makes it very advantageous. The success of this injection will be increased by throwing in first, a syringe full of No. II. properly heated, with a view of warming somewhat the vessels and removing their rigidity. In the use of No. I, II., and III. it is indispensable to warm the subject thoroughly by previous immer- sion in water hot enough to excite the sensation of INTRODUCTION. XXl scalding in the finger. If the water be warmer it will cause the parts to contract and become rigid instead of softening them. The injections must be of a pro- portionate temperature. The more limited the range of an injection is, the more likely it will be to succeed well, as the force of the syringe is thereby concentrated. Hence a rule is established to put the pipe as near as possible to the part intended to be injected. No. I. is used for dried preparations. No. II. is sometimes used as the precursor to No. I. No. III. is adopted in wet preparations and such as are intend- ed to demonstrate minute vascularity. No. IV. an- swers remarkably well for dried preparations; it takes about twenty-four hours to harden; the part injected should, therefore, not be disturbed till the expiration of that period. The student acquainted with the circulation of the blood will always know where to fix his pipes when an injection is to be accomplished, whether arterial or venous, or both. It is therefore unnecessary to extend this paper by describing the method of pro- ceeding in each individual preparation, general rules being sufficient, and to the intellectual mind much more acceptable. xxii INTRODUCTION. DRIED PREPARATIONS. Whenever a section of the body, as the head, the arm, leg, and so on, is to be injected, the arterial pipe must be fixed into the principal trunk or trunks of the part: the venous pipe into one of the extreme branches. A very common, and, indeed, the most frequent source of misfortune to the young anatomist, is the neglecting to take up such vessels as were cut in the separation of the part. It may be avoided by blowing into the pipes when fixed, which distending all the ramifications, such as are cut can be thus easily found out and secured. Male subjects, from birth till the age of twenty-five or thirty, answer best for dried preparations of the greater part of the arterial system. After thirty, few subjects answer well in consequence of the profusion of adeps blending itself with the muscles, and not un- frequently a diseased state of the arterial system. In dried preparations the arteries should be fairly traced in all their ramifications, and the muscles sepa- rated from each other. All other parts not essential to the object of the preparation must be cut away When the part is to be dried, care should be taken to put every portion of it in a proper posture, and to fix INTRODUCTION. xxiii it so till it becomes stiff. The muscles are to be sepa- rated with strips of wood. When the preparation is thoroughly dried, and not before, it should be varnished. But before the lat- ter is done the preparation should be washed twice with a solution of caustic potash, in order to remove a greasy coat which it is apt to form on its surface. It should afterwards be washed with water to remove the soap that results from the application of the potash. Soap-boiler's ley answers perfectly in the place of the caustic potash of the shops. Dried preparations suf- fer much from insects, and the best security from them is obtained by immersion in a solution of corrosive sublimate, till they become impregnated with it; they may afterwards be put in position and dried. If they are too large to subject to this process, even after they are dried they may be washed advantageously with this mixture four times. Corrosive Sublimate 31. Muriate of Ammonia, 3iss. Water, fl^i. Mix. At the two last washings add Common Glue, dissolved, ^i. to the foregoing mixture. The glue makes the mixture adhere to the prepa- Xxiv INTRODUCTION. ration, and also lays a basis or ground for the varnish which makes it stick and dry well. Two thin coats of copal varnish must afterwards be laid on with a soft brush. CORRODED PREPARATIONS. The heart, lungs, liver, spleen, pancreas, kidneys, and penis are most commonly used in making corrod- ed preparations. Their vessels, excretory ducts, and cavities, as the case may be, should be distended mo- derately with the coarse injection, observing to give to each system in the structure of the viscus a colour different from the rest. The successful injection of these requires good management, because, if too much force be used, extravasation will occur and the pre- paration will be materially disfigured. After injection, the preparation is to be laid in a mixture of three parts of muriatic acid with one of water, which corrodes the fleshy part and leaves the injection exposed. The process of corrosion occupies from three weeks to two months, according to the bulk of the viscus. The acid becomes weakened during the time, and we should, therefore, every week add enough fresh to bring it to its original strength. The fleshy part being converted in a soft pulp, the preparation is to be taken out of the mixture with the INTRODUCTION. XXV greatest care and subjected to a small gentle stream of water, which washes off the pulp and leaves the vessels bare. If the corrosion be unfinished, after this process, the part must be replaced in the acid mixture and kept there till it is completed. The pulp being removed, let the preparation remain floating in water for twenty hours in order to remove any acid which may adhere to it; then d:y it by suspension in the air or by laying it on a heap of soft carded cotton, covered with a thin muslin cloth in order to prevent the cotton from sticking to its vessels. The preparation should be fixed on a plaster of Paris pedestal, and varnished by dipping it into copal varnish diluted with one-half its quantity of spirits of turpentine. It should, after drying, be varnished in the same way once more. Such preparations, when kept under glass bells or cases, are among the most beautiful that can be made. WET PREPARATIONS. Minute injections, for the most part, and all mor- bid appearances are proper articles for wet prepara- tions. The natural structure of many parts is also very advantageously displayed in this way. The pre- paration should be previously steeped in water, chang- ed daily, till all the blood is out. d xxvi INTRODUCTION. Spirits of wine, spirits of turpentine, and asolu'ion of corrosive sublimate are each excellent for suspend- ing such preparations in. The latter answers parti- cularly well for eyes and for thin membranous parts, as an intestine, &c. Two grains of corrosive subli- mate, with an equal quantity of muriate* of ammonia, to an ounce of water, makes a solution sufficiently anti- putrescent for an eye, and contracts the preparation much less than spirits of wine. WThen larger bodies are preserved the quantity of corrosive sublimate must be increased proportionally. Bottles for wet preparations should have wide mouths, short necks, and broad heavy bottoms. The preparation being properly displayed and suspended, the mouth of the bottle must be secured with a blad- der; over this sheet lead must be placed about the thickness of a quarter of a dollar, being trimmed so as to correspond in size with the top of the bottle, and over this lead another piece of bladder is to be stretch- ed and secured. The outside bladder, being properly trimmed, should be varnished twice with copal var- nish coloured with lampblack. QUICKSILVER INJECTIONS. These constitute a beautiful and interesting depart- ment in the occupations of the practical anatomist. The parts most frequently subjected to this process INTRODUCTION. xxvii are the lymphatic and lacteal systems. In the extre- mities we introduce the tube at the point farthest from the heart, and having injected one trunk, the pipe must be withdrawn and introduced into another, and so on till all the trunks are filled. In injecting for the lac- teals we must introduce the pipe into a lacteal trunk in the mesentery and inject backwards; the lacteals, on the intestine itself, being, for the most part, too small to admit of its introduction into them. The Liver has a great many lymphatics in its peri- toneal coat; they may be injected from one of the trunks on the broad ligament. It is unnecessary to preserve the whole liver; a section of it half an inch thick, dried and hung in spirits of turpentine answers very well. The Parotid Gland affords a fine preparation by having its duct injected with quicksilver. The injec- tion must be made before the gland is removed from the body; the blood should afterwards be soaked out, and the gland dried and hung in spirits of turpentine. The Vesiculae Seminales and the Testicles injected with quicksilver are also excellent subjects for this kind of preparation. The lactiferous ducts of the mammae are very favourably displayed in the same manner; they are injected separately from the nipple. XXviii INTRODUCTION. V woman who has died during lactation is the best subject for it. The hand of a thin, aged female may be readily in- jected, both arteries and veins, by a pipe fixed into the radial artery. After it is filled it should be macerated in water frequently changed till all the blood is re- moved and the cuticle comes off; it should then be dried and varnished. The Veins of the kidney of a cat are said to afford a beautiful preparation with quicksilver. PREPARING BONES. Bones are best prepared by maceration in warm weather, and a dropsical subject is much better than any other, from the marrow being less abundant and mixed with serum. The skeleton should be roughly cleaned and put into a macerating vessel, the brain being removed. The water should be changed daily as long as it is discoloured by the blood. Afterwards it should be left till putrefaction has softened and dis- solve^ all the ligaments and soft parts. The skeleton should then be taken out and washed well in clean water with a little ley added to it. It is then to be dried and is fit for use. If the maceration be pro- perly conducted no bleaching is necessary; if other- wise, the process adopted in whitening linen and cot- INTRODUCTION. XX1X ton clothing answers well, that is, exposure to the sun and frequent wetting with water. A cranium from four to ten years old treated in this way affords a fine preparation for studying its bones in a state of separation. To accomplish the latter it is only necessary to fill its cavity with peas or beans after the maceration is over, and to immerse it in warm water. The beans in a short time begin to swell and open the sutures completely. The bones of the face must be taken asunder with the fingers. In order to show the animal part of bone only, take a section of it and immerse it in an acid mixture com- posed of muriatic acid one ounce, and water one quart. In from one to four months, according to the size and solidity of the bone, the calcareous part will be taken away by the acid. On such a preparation one may demonstrate the pliability and the lamellated and fibrous texture of the hardest bone. A bone, by being thrown into a strong fire, will have all its animal part destroyed and nothing but the calcareous left. This preparation is the reverse of the last. To demonstrate the vascularity of bone, cut off the limb of a fcetus or young child and fix a pipe into the principal artery. By filling'the part with the minute xxx INTRODUCTION. injection, the vessels of the bone will also be injected. Remove the flesh when it becomes cold, and macerate in water till the blood is washed out. Place the bone in the acid mixture just mentioned till the calcareous partis removed; soak it in pure water again for a day, then dry it, and finally immerse it in spirits of turpen- tine to make it transparent. ON FUMIGATION. The air of rooms where dead bodies are kept, as well as the walls and furniture, become exceedingly offensive; to correct which we resort to the following mixture with great advantage. Take Black Oxyd of Manganese, ^i. Common Salt, 5ij. Sulphuric Acid, 3vi. Water, ^ss* The water and the acid should be previously mix- ed and allowed to cool. Then stir all the ingredients well together in a stone vessel. When the room is abandoned for the night, close its doors and windows and commence this fumigation. The next morning it will be found much sweetened, and on ventilating freely its atmosphere will loose still more of its offensiveness and be in a great mea- sure renovated. INTRODUCTION. XXxi The fumes of this mixture are very penetrating; they give their peculiar smell to clothing for several days, and rust metallic surfaces intensely. All articles, therefore, which are not intended for such depuration should be removed. / LESSONS IN PRACTICAL ANATOMY. PART I. OF THE HEAD AND NECK. CHAPTER I. Of the External Parts of the Head and Neck. The integuments of the head are remarkably thick and hard, but give the sensation, when felt exter- nally, of being a very thin layer spread over the bones. The latter is particularly the case as far as the hair extends. They consist of skin, and below it of small, compact, granulated masses of fat enclosed in the cells of a cellular substance, which has very much of a ligamentous character, and adheres closely to the muscle beneath. The muscles of the face should always be dissected as early as possible after death; under the most fa- vourable circumstances they are difficult for the stu- A 2 OF THE HEAD AND NECK. dent to make out, and are rendered unintelligible to him in a few days by the changes which their dimi- nution of volume, infiltration, and confusion of colour with contiguous parts produce. I would also advise one side of the face and neck to be appropriated exclusively to the dissection of the fasciae, muscles, and glands; every thing, therefore, should be removed which interferes with a thorough examination of them. The student having accom- plished this, may afterwards work on the other side of the subject for the blood-vessels and nerves. To trace the arteries properly, they ought to be filled previously with common injection; tallow, coloured with red lead, answers very well; the veins it is of less importance to inject. It is unnecessary to heat the subject for such injection. Section I. OF THE MUSCLES AND FASCIAE. The Occipito-frontalis muscle consists of two symmetrical parts, and coming from the back of the head is inserted into the front of it; it has four bellies of muscular fibres, two behind and two before, con- nected by a thin tendon which covers all the top of the head. The dissection of this muscle is difficult, from the close adhesion of its tendon to the pericranium MUSCLES AND FASCIA. .3 below, and to the integuments of the head above. It is best, therefore, to commence by making one inci- sion through the integuments only, from the root of the nose to the end of the sagittal suture, and another from the commencement of this, along the upper mar- gin of the eyebrows to the external angular process of the os frontis; by raising up this flap it leads to the dissection of the whole muscle. It arises from the superior transverse ridge of the os occipitis by tendinous and fleshy fibres, which form two distinct bellies about an inch and a half long, one on each side of the bone. Its tendon, when care- fully traced, will be found terminating a little in front of the coronal suture in the two anterior fleshy bellies which cover the whole front part of the os frontis. The internal edges of these latter are in conjunction below. It is inserted fleshy, on each side, into the superior margin of the orbicularis oculi and corrugator super- cilii, and by its nasal slip into the internal angular process of the os frontis and into the root of the ossa nasi. It pulls the skin of the head backwards and for- wards, and throws the forehead into horizontal wrin- kles. It also elevates the supercilia. The Compressor Naris arises by a pointed begin- ning from the root of the ala nasi; it spreads like a fan over the lateral parts of the nose below, is inserted into i OF THE HEAD AND NECK. its fellow of the opposite side on the dorsum of the nose. and into the lower part of the os nasi where it is con^ hected with the nasal slip of the occipito frontalis. This muscle consists of thin and pale fibres imme- diately under the skin. If it act from both extremi- ties, by its curved fibres being made straight, it will compress the nostril; but if it act from its dorsal mar- gin assisted by the nasal slip of the occipito frontalis, it will dilate the ala nasi, and has, therefore, been called dilatans nasum by Columbus. The Orbicularis Palpebrarum is a broad circu- lar muscle, lying immediately under the skin of the eye- lids, and over the tarsi cartilages. It covers the whole front of the bony orbit and extends from four to eight lines beyond its margin, being connected to subjacent parts by cellular tissue; its temporal section is firmly fastened to the temporal fascia beneath. It arises fleshy from the internal angular process of the frontal bone and from the upper edge of the round horizontal tendon that fixes the internal commissure of the eyelids to the nasal process of the superior max- illa. These fibres perform the circuit of the eyelids, and, coming around to the internal canthus again, are inserted into the orbital margin of the nasal process, and of the orbitar process of the upper maxilla, into the lower edge of the horizontal tendon, and into the nasal process just beneath it. MUSCLES AND FASCIAE. 5 The Ciliaris muscle is the internal margin of the orbicularis planted on the edges of the tarsi cartilages. As the Orbicularis muscle is fixed at its nasal and temporal sections more than elsewhere, it is obvious that the contraction of its circular or curved fibres by bringing them straight, will close the eyelids and wrinkle the skin on them. This muscle frequently has a slip from its lower border to the upper lip, an- terior to the zygomaticus minor. The Corrugator Supercilii is placed at the in- ternal end of the superciliary ridge. It arises from the internal angular process of the os frontis, and passing obliquely upwards and outwards between the lower edge of the occipito frontalis and the upper edge of the orbicularis, is concealed by them. It is inserted into the former principally, but its fibres also blend with the latter. It draws the forehead into vertical wrinkles. The Levator Labii Superioris Al^iqui Nasi is fixed just at the side of the nose. It arises by a point- ed production from the nasal process of the superior maxilla at the internal canthus of the eye, and by a broad origin from the anterior margin of the orbitar process of the same bone. Passing downwards it is inserted into the side of the ala nasi, and into the up- per lip, being narrower below than above. Tt draws the upper lip and the ala nasi upwards (j OF THE HEAD AND NECK The Levator Anguli Oris is a small muscle con- cealed very much by the last; it arises from the ante- rior part of the superior maxillary bone, between the foramen infraorbitarium and the first small grinder. and is inserted into the corner of the mouth. It raises up the angle of the mouth. The Zygomaticus Minor is a small muscle some- times deficient, arising from the fore part of the os make; it descends obliquely and is inserted into the upper lip just above the corner of the mouth. The Zygomaticus Major, being just on the out- side of the last and much larger, arises from the malar bone externally, at its posterior inferior part just above the lower edge, where this bone contributes to form the zygoma, and passing obliquely downwards it is inserted into the corner of the mouth, running into the depressor anguli oris. These two last muscles draw the corner of the mouth towards the cheek bone, or obliquely upwards and outwards as in smiling. The Depressor Labii Superioris Al^equi Nasi is concealed by the orbicularis oris and the levator labii superioris alaequi nasi. To get a view of it the upper lip must be inverted and the lining membrane of the mouth removed on the side of the frsenum of the lip. This muscle arises from the inferior part of the MUSCLES AND FASCIJE. 7 upper maxilla in front t>f the alveolar processes for the dens caninus and the incisores, and is inserted into the side of the ala nasi and into the contiguous part of the upper lip. It depresses the upper lip and the ala nasi. The Depressor Anguli Oris arises broad and fleshy from the base of the lower jaw on the side of the chin; being somewhat triangular, its apex is inserted into the corner of the mouth. This muscle draws the corner of the mouth down- wards. It lies immediately under the skin, and blends above with the zygomaticus major and with the leva- tor anguli oris. The Depressor Labii Inferioris is in part be- neath the last muscle, and, like it, arises broad and fleshy from the basis of the lower jaw on the side of the chin; its fibres pass obliquely upwards and inwards and are inserted into the whole side of the lower lip. It draws the lip downwards. These two last muscles are much obscured by be- ing mixed with a quantity of adipose matter; the skin, also, is closely blended with them, and the roots of the beard penetrate between the intervals of their fibres. The Levator Labii Inferioris, being placed be- neath the depressor labii inferioris, is demonstrated by 8 OF THE HEAD AND NECK. turning downwards the lower lip and dissecting away its lining membrane on the side of the fraenum; it will then be seen to arise in front of the alveolar process of the external incisor and the canine tooth, and pass- ing obliquely downwards to be inserted into the lower up. It elevates the lower lip. The Buccinator muscle arises from the root of the coronoid process of the lower jaw bone, from the back part of the upper maxilla near the pterygoid process, and from the roots of the alveolar processes of both bones as far forwards as the dentes bicuspides. It is inserted into the corner of the mouth and into the contiguous parts of the upper and lower lip. It draws the corners of the mouth directly back- wards. The Orbicularis Oris is a circular muscle just beneath the skin, much blended with adipose matter externally, but more plain on the surface contiguous to the lining membrane of the mouth. It constitutes a considerable part of the thickness of the lips, sur- rounding the mouth entirely. It has no bony origin, but arises from the fibres of the several muscles which join each other at the corner of the mouth, and, there- fore, consists of two semicircular planes, one for the upper, and the other for the lower lip. It is the antagonist to most of the other muscles of MUSCLES AND FASCLE. 9 the mouth. From its superior part a pyramidal slip goes to the tip of the nose called by Albinus, Nasalis Labii Superioris. The Masseter is placed immediately under the skin, and forms the fleshy protuberance on the back of the face before the ear. It arises tendinous and fleshy from the malar process of the upper max- illa, and from the inferior edge of the malar bone be- tween the maxillary and zygomatic sutures; it arises also from the temporal bone between the zygomatic suture and the tubercle. The masseter covers all the exterior surface of the ramus of the lower jaw as low down as its base. It is divided into two portions which lie one beneath the other; the internal is the smaller, and is inserted tendinous into the outer part of the root of the coronoid process. The external ex- tends from the malar bone to the angle of the inferior maxilla, where it is inserted tendinous and fleshy. A part of the internal portion may be seen at the zygo- matic suture behind the external, without the latter being raised up. It closes the jaws. The Temporalis lies on the side of the head oc- cupying its middle inferior region; it is covered exter- - nally by a thick dense tendinous membrane, the fas- cia temporalis, which arises from the semicircular B 10 OF THE HEAD AND NECK. ridge on the side of the cranium, and is inserted into the upper margin of the zygoma. By removing this fascia, the temporal muscle is seen to arise fleshy from its inner surface, from the semicircular ridge on the side of the os frontis and parietale its whole length, also from the surfaces of bone below this ridge and above the zygoma including a part of the frontal bone, the lower part of the parietal, and the squamous por- tion of the temporal. From this extensive origin, the fibres converge towards the zygoma and are in- serted tendinous into the coronoid process of the lower jaw, surrounding it on every side; some of these ten- dinous fibres in front go down nearly as low as the last dens molaris. The temporalis receives a small accession of fleshy fibres from the internal face of the zygoma. It pulls the lower jaw directly upwards. Of ihe Muscles of the .Keck. The dissection of this part can now be advantageously pursued; with this view, make one incision through the skin along the clavicle and upper edge of the sternum, another from the chin over the thyroid cartilage to the ster- num, and a third frotn the chin to the upper part of the ear. The flap which is thus marked out is to be • raised carefully without cutting up a superficial mem- brane that lies immediately below the skin called Fas- cia Superficialis. This fascia is a continuation of the MUSCLES AND FASCIA. 11 one placed in front of the abdominal muscles, which passes from them to the thorax and afterwards to the neck. Its connection with the clavicle and sternum is not very strong, and it goes from them along the neck to the face, being slightly fastened to the base of the lower jaw in advance of the masseter muscle. It is spread over the parotid gland, is fixed to the mastoid process, to the meatus auditorius, and to the zygoma; in the latter place it is continuous in some measure with the fascia temporalis. The existence of this membrane is thought, by Mr. Colles of Dub- lin, to obscure very much the affections of the neck and of the parotid gland, checking the development of tumours, rendering their fluctuation and particular feel very equivocal, and giving a wrong course to their pus when they suppurate. The fascia superficialis is better expressed over the parotid gland and about the base of the jaw than lower down. The Platysma Myoides muscle, or the Musculus Cutaneus, is immediately beneath the fascia superfi- cialis, covering a very considerable portion of the side of the neck, and extending from the thorax obliquely to the face. It arises from the condensed cellular membrane on the upper part of the pectoralis major muscle and the « deltoid, just below the clavicle and nearly the whole length of this bone. Its fibres are much more pale [2 OF THE HEAD AND NECK. than those of other muscles, are collected into longi- tudinal fasciculi, constituting a plane of scarcely a line in thickness, and terminate in the integuments of the lower jaw and cheek. It is slightly attached to the lower jaw, and sometimes has the appearance of run- ning into the muscles of the lower part of the face. When the whole muscle is in action it elevates the skin of the neck. The external jugular vein is seen running nearly in the centre of it in the same direc- tion with the fibres of this muscle between it and the sterno-mastoid. The Sterno-Cleido-Mastoideus is beneath and decussates the last muscle. It forms always a pro- minent feature in the outline of the neck, passing ob- liquely from the upper front part of the thorax to the base of the cranium. It arises tendinous and fleshy from the edge of the upper part of the sternum, and fleshy from the sternal end of the clavicle. These portions are separated by a considerable fissure; they soon unite and are insert- ed tendinous into the mastoid process and part of the transverse ridge of the occipital bone next to it. It draws the chin towards the sternum. This mus- cle is to be detached from its origin, and allowed to hang aside by its insertion, in order to get at the parts beneath. We shall then see two narrow, handsome ribbon-like muscles on each side of the middle line of MUSCLES AND FASCIJE. IS the trachea; they are the sterno-hyoideus and sterno- thyroideus. But before we go to the dissection of them, it is necessary to look at another fascia of the neck. When the origin of the sterno-cleido-mastoideus is turned to one side, beneath the fascia superficialis and somewhat separated from it by a lamina of cellular adipose matter, is the Fascia Profunda of the neck. This membrane arises from the larynx, forms a thin capsule to the thyroid gland, and, being closely attach- ed to its inferior margin, it descends by investing the sterno-hyoid and thyroid muscles, being strong and well marked on their anterior surfaces. It is firmly fastened to the upper edge of the sternum, the sternal end of the clavicle, and to the cartilages of the first ribs, forming an elastic and resisting membrane from the larynx to the thorax. By turning off the sterno- hyoid and thyroid muscles from their attachment to the sternum, the fascia profunda will be seen still more distinctly passing behind them from the inferior mar- gin of the thyroid gland to the upper bone of the ster- num, this lamina of it being inserted into the sternum twelve or fifteen lines below its upper edge. It en- closes or surrounds the transverse vein and the ar- teria innominata. Beneath the fascia profunda, are the trachea, the roots of the arteries of the head and upper extremities, and the trunks of their veins. There is much loose cellular and adipose matter plac- 14 OF THE HEAD AND NECK. ed at the lower part of the neck beneath this fascia, between it and the trachea, through which the thyroid veins with their ramifications pass. This last circum- stance must always render suppurations and opera- tions in the part highly dangerous, as there are no means to prevent the pus from forming fistulas under the sternum; moreover, the continual motion of the part in respiration prevents adhesion from forming, and, therefore, disposes to ulceration. An ingenious idea on the uses of this fascia and of the sterno-hyoid and thyroid muscles as connected with it, was sug- gested by the late Allan Burns; he conceived that they were a defence to the upper part of the thorax, and sustained the atmospheric pressure, which, without them, would fall upon the trachea and produce diffi- culty of breathing, from the air not passing through the larynx sufficiently rapidly to keep pace with the dilatation of the thorax. He illustrates the opinion by a case very much in point, of a gentleman who had lost this fascia and the muscles by suppuration, and who was afterwards incommoded by atmospheric pressure upon the trachea at this point.* The external borders of the fascia profunda are * Dr. Laurance informs-me that this fascia profunda is well developed in the neck of a cat, and that having occasion to re- move it in an experiment; the respiration of the animal was conducted with great difficulty, amounting almost to suffoca- tion. This is a good confirmatian of Mr. Burns's hypothesis. MUSCLES AND FASCLE. 15 continued into the sheaths of the great vessels of the neck. It and the fascia superficialis are also continu- ous with each other along the anterior edge of the sterno-cleido-mastoideus. Within the inferior maxilla, at its angle, a ligamen- tous expansion arises from the pterygoideus externus muscle, and is spread out between the styloid process and the ramus of the lower jaw. This membrane is joined by the fascia superficialis at its inferior edge, just before the upper part of the sterno-mastoideus, which increases its breadth downwards in the neck, giving it somewhat the condition of a vertical septum of that region, and at its lower edge it runs into the theca of the great vessels of the neck. Through its lower part penetrate the stylo-hyoideus and digastricus muscles, and the upper part separates the parotid from the submaxillary glands. It is felt like a chord ex- tending downwards and backyvards below the angle of the maxilla inferior. It is connected at its internal edge with the compages of the nerves and vessels of the part in such a manner as to forbid description, but which the practical anatomist will find no diffi- culty in discovering and understanding. Below this septum a round ligament like a nerve passes from the extremity of the styloid process to the appendix of the os hyoides. The Sterno Hyoideus arises thin and fleshy from 16 OF THE HEAD AND NECK. the interior of the thorax on the approximated sur- faces of the cartilage of the first rib, the clavicle, and the first bone of the sternum; it passes upwards some- what obliquely and is inserted into the inferior edge of the base of the os hyoides. It drayvs the os hyoides towards the sternum. The Sterno Thyroideus is below the last and concealed in a considerable degree by it. It arises fleshy from the interior surface of the sternum, about an inch below its upper margin, and from the carti- lage of the first rib, and diminishing in breadth some- what as it ascends, is inserted obliquely into the side of the thyroid cartilage. It draws this cartilage towards the sternum. The Omo Hyoideus passes obliquely across the neck from the superior edge of the scapula to the os hyoides. It is a thin narrow muscle divided into two bellies, one at each end, by an intermediate tendon, its inferior part is concealed by the trapezius muscle, its middle, where the tendon exists, crosses the great vessels of the neck and is covered by the sterno- cleido-mastoid muscle, and its upper extremity is over- lapped by the platysma myoides. It arises from the scapula just behind the notch in its superior costa, and curving somewhat downwards MUSCLES AND FASCIjE. 17 in its course, is inserted into the lower edge of the base of the os hyoides next to its corner. It drayvs the os hyoides downwards. The Digastricus is a double-bellied muscle at the upper side of the neck, passing from the back part of the base of the head to the chin. It arises from the fossa of the temporal bone at the inside of the mas- toid process, principally fleshy; as the muscle descends towards the os hyoides, a round tendon forms its mid- dle part, which passes through the stylo hyoideus mus- cle, and is fixed, by a ligamentous loop, to the cor- nu of the os hyoides. After this the muscle becomes again fleshy, and is so inserted into the inside of the base of the maxilla inferior at the side of the chin. It receives an accession from the base of the os hy- oides. It draws the os hyoides upwards. By raising the posterior belly of this muscle we get a better view of the styloids, which are three in number, and placed within it. The Stylo Hyoideus, being the more superficial of the three, arises tendinous from the middle and in- ferior part of the styloid process of the temporal bone, and being perforated, as mentioned, by the tendon of the digastricus, is inserted tendinous into the cartila- c 18 OF THE HEAD AND NECK. ginous juncture of the base and cornu of the os hy- oides. It draws the os hyoides upwards and backwards. The Stylo Glossus is within and above the other; it arises from the upper internal part of the styloid process, tendinous and fleshy, and is inserted into the side of the root of the tongue forming a part of its structure. It draws the tongue backwards. The Stylo Pharyngeus is more deeply situated than either of the other two muscles. It arises from the inner side of the styloid process near its root, and is inserted into the side of the pharynx between the middle and lower constrictors, and into the posterior edge of the thyroid cartilage. It draws the larynx and pharynx upwards. The Mylo-Hyoideus forms the floor of the mouth and suspends the tongue; it arises from a ridge at the root of the alveolar processes of the lower jaw ex- tending from the last dens molaris to the chin. Its fibres converge towards a white tendinous line placed between it and its fellow, and extending from the base of the os hyoides to the chin. This muscle lies im- mediately below the anterior belly of the digastricus, and when it contracts, it draws the os hyoides up- wards and projects the tongue. MUSCLES AND FASCLE. 19 The Genio-Hfoideus is immediately below the last, by turning down the anterior edge of which, it is seen. I arises tendinous from the tubercle on the side of the symphysis of the lower jaw posteriorly, and, increasing somewhat in breadth, is inserted into the anterior part of the base of the os hyoides. It draws the os hyoides upwards and forwards. By removing this muscle we bring into view The Genio-Hyo-Glossus, which arises also ten- dinous from the tubercle on the inside of the maxilla inferior near the symphysis, and is inserted into the base of the os hyoides and into the tongue its whole length, constituting a part of its substance. The mus- cles of the opposite sides are in contact and throw the tongue into a great variety of positions, according to the fibres which are brought into action. The Hyo-Glossus is just on the exterior of the last. It arises from the base and part of the cornu of the os hyoides broad and fleshy, and is inserted into the side of the tongue. It draws the tongue inwards and downwards. The Lingualis may also be seen in part in this dissection. It is one of the intrinsic muscles of the tongue, and lies on the outer side of the last. For a 20 OF THE HEAD AND NECK. further account of thes'e muscles .of the tongue, see the article Mouth. There are four pairs of muscles situated behind the pharynx and oesophagus close to the cervical ver- tebrae, which can only be seen imperfectly in this dis- section. 1. The Longus Colli is next to the middle line of the vertebrae, and arises from the sides of the bo- dies of the three superior vertebrae of the back, and from the anterior edges of the transverse processes of the five lower cervical vertebrae. Its fibres pass somewhat obliquely upwards and inwards to be in- serted into the front of the bodies of all the cervical vertebrae. It bends the neck forwards and to one side. 2. The Rectus Capitis Internus Major arises tendinous and fleshy from the fronts of the transverse processes of the third, fourth, fifth and sixth cervical vertebrae, forms a considerable fleshy belly, and is in- serted into the cuneiform process of the os occipitis just before the condyle. It is placed on the outside of the longus colli, and bends the head forwards. 3. The Rectus Capitis Internus Minor arises fleshy from the front of the body of the first cervical MUSCLES AND FASCLE. 21 vertebrae near its transverse process, and is inserted under the rectus major before the root of the condy- loid process of the occipital bone. It bends the head forwards. 4. The Rectus Capitis Lateralis arises fleshy from the front of the transverse process of the atlas, and is inserted tendinous and fleshy into the ridge on the outside of the condyle of the occiput, leading from it to the mastoid process. It pulls the head a little to one side. On the outside of these muscles, passing from the exterior edges of the cervical vertebrae to the upper parts of the thorax, are the Scaleni muscles, being three in number, named from their situation. 1. The Scalenus Anticus arises by three distinct tendinous heads from the transverse processes of the fourth, fifth and sixth cervical vertebrae, and is in- serted tendinous and fleshy into the upper edge of the first rib just anteriorly to its middle. 2. The Scalenus Medius arises by distinct ten- dons from the transverse processes of all the cervical vertebrae, and is inserted tendinous and fleshy into the upper part of the first rib, in all the space from its middle to its tubercle. 22 OF THE HEAD AND NECK. 3. The Scalenus Posticus arises from the trans- verse processes of the fifth and sixth cervical vertebrae, and is inserted into the upper face of the second rib j"ust beyond its tubercle. These muscles are concealed by the sterno-cleido- mastoideus and the anterior edge of the trapezius; to be well seen, the clavicle should be loosened from the sternum and thrown off to one side. The third Sca- lenus is best seen in dissecting the muscles of the spine, and resembles very much one of that class to which Albinus gives the name of Levatores Costarum. All the Scaleni elevate the ribs and bend the neck to one side. They are particularly interesting as con- nected with the course of the large blood-vessels and nerves of the upper extremity, which will be more particularly alluded to in the dissection of the axilla. This is a proper place also for looking at the Pte- rygoid muscles; they are, however, but imperfectly seen. The only way to get a very good view of them is to make the dissection on a vertical section of the head, or on a head detached from the cervical ver- tebrae, which can be done very conveniently when we are engaged in the study of the nose, or of the pharynx. The Pterygoideus Externus arises fleshy from the outer side of the external pterygoid process of the GLANDS. 23 sphenoid bone, from the tuber of the upper maxilla, and from the under surface of the temporal process of the sphenoid bone. It passes outwards and back- wards horizontally, and is inserted into the inner side of the neck of the inferior maxilla and into the cap- sular ligament of the articulation. The Pterygoideus Internus arises from the outer side of the internal plate of the pterygoid process of the sphenoid bone, at its upper part, just by the Eus- tachian tube, by tendinous and fleshy fibres. It fills up the most of the pterygoid fossa, and passing down- wards and backwards, is inserted tendinous and fleshy into the interior face of the angle of the lower jaw. Both of these muscles are important in mastica- tion; they close the jaws, throw the lower one for- ward, and produce the grinding motion by acting al- ternately. Section If of the glands of the head and nbck. The Thyroid Gland, (Gland. Thyroidea,) con- sisting of two lobes united by an isthmus, is placed on each side of the upper part of the trachea, extending 24 OF THE HEAD AND NECK. upwards laterally by the cricoid cartilage to the thy- roid. It resembles a pair of saddle-bags in its gene- ral outline, the upper edge, however, being very much excavated or crescentic, with the horns pointing up- wards. The isthmus passes over the second ring of the trachea, and is firmly fixed to it by a short cellu- lar substance. Loder in his plates of this body re- presents a muscle, quoted from Soemmering's Ana- tomy, passing on the left side of the larynx, from the base of the os hyoides to the upper edge of the thy- roid gland, to which he gives the name of Musculus Glandulae Thyreoideae. Its occurrence in this coun- try is, I presume, exceedingly rare, as out of several hundred subjects which I have superintended the dissection of, not one example of it has been noticed. This gland is covered by the sterno-hyoid and thy- roid muscles. It is of a dark brown colour, has a capsule from the contiguous cellular membrane or fascia, besides its own proper coat. The structure of it is very imperfectly understood; the most that we know is, that it is extremely vascular; when cut into or inflated it exhibits a great number of cells com- municating with each other, of different sizes, and containing an unctuous and somewhat transparent fluid, and that it has no excretory duct. On each side of the neck are three large salivary glands, the Parotid—the Submaxillary—and the Sub- lingual. GLANDS. 25 The Parotid Gland (Glandula Parotis) is the inost considerable of the three, and its form is very irregular, depending on the space into which it is crowded. It extends from the zygoma downwards to the angle of the jaw, occupying the space from the mastoid process and meatus auditorius to the ramus of the jaw, and extending from the skin externally to the internal carotid artery internally; its connections are numerous and exceedingly intricate. It is re- moved in the dead subject from the contiguous parts with great difficulty, and in the living subject its safe extirpation would be next to a miracle. The portio dura nerve and several large branches of the exter- nal carotid have to penetrate directly through its sub- stance in order to arrive at their destinations. It has been observed that this gland is covered ex- ternally by an extension of the fascia superficialis of the neck; from the interior face of this fascia many prolongations are sent out which penetrate the gland in every direction, separating its lobules from each other and conducting the blood-vessels and nerves through its substance. The parenchyma of the gland is formed of small rounded granulations of a light pink colour, united into lobules of various forms; an arte- riole may be injected, going to each of them. The parotid gland is elongated at its anterior mar- gin into a point, lying on the posterior part of the masseter muscle. From the upper part of this point D 26 OF THE HEAD AND NECK. proceeds the parotid duct and crosses the masseter muscle about eight lines below the zygoma, and, ac- cording to the observations of Dr. Physick, in a line from the under part of the lobe of the ear to the tip of the nose. The parotid duct, or Ductus Slenonia- nus, is about the size of a crow quill; it arises from the granulations of the gland, by ramuscules which, uniting successively, form this large duct. The gland being sometimes divided into two lobes, each has an excretory duct which joins the other, half an inch in front of the anterior edge of the gland. The common duct lies close to the masseter muscle, and may easily be overlooked by the young anatomist; for- wards it dips over the edge of this muscle into a fatty mass between it and the buccinator, and, perforating the latter, has its orifice in the mouth, opposite the second large molar tooth of the upper jaw. At the posterior part of this duct, between it and the zygoma, a small gland, varying, however, in its size and form, is situated, called by Haller the ac- cessory of the parotid. It is not always found. The Submaxillary Gland (Gland. Sub-Maxil- laris) is irregularly ovoid. It is situated below the musculus cutaneus in the space bounded by the di- gastric muscle below, the mylo hyoid towards the mouth, and the body of the lower, jaw externally,__ is in contact with the facial artery and the lingual GLANDS. 27 branch of the fifth pair of nerves. It almost touches the parotid gland behind, being separated from it only by the septum sent in from the fascia superficia- lis, and at the posterior edge of the mylo hyoideus it touches the sublingual gland. Its structure is the same with that of the parotid gland, except the capsule with its internal prolonga- tions of cellular membrane, which are much looser. It has an excretory duct, (Ductus Warthonianus,) arising in the same way by ramuscules, but much thinner and more extensible than the parotid duct; it penetrates between the back edge of the mylo hyoid and the hyo-glossus muscles, and continues between the genio-hyo-glossus and the sublingual gland; from the latter it receives occasionally several branches, and terminates by an orifice on the side of the frae- num linguae near its edge. The Sublingual Gland (Glandula Sublingualis) is placed under the lining membrane of the mouth between the side of the tongue and the mylo hyoid muscle, and being oblong it is parallel with the genio- hyo-glossus where it is about to join the tongue. This gland is not uniform in the arrangement of its excretory ducts. Sometimes it has eighteen or twenty excretory orifices in the lining membrane of the mouth; on other occasions several of these short ducts are collected into one or two principal trunks 28 OF THE HEAD AND NECK. which open either directly into the mouth or into the duct of Wharton. By turning up the tip of the tongue, the projection of this gland is readily seen, as well as several salivary granulations, or little glands, which border on it. Lymphatic Glands. Medical men are often con- sulted on the subject of indurated and not very pain- ful swellings in the neck, which most frequently are enlarged lymphatic glands. In a course of dissections these should by no means be overlooked, as they are very numerous. They vary much in size and num- ber; being for the most part flattened ovals, some are not more than two lines in their long diameters; others are nine or ten lines long. They are both su- perficial and deep-seated. Between the skin and the insertion of the sterno- mastoid muscle there are from four to six; in the in- terstice just above the clavicle between the posterior edge of the sterno-mastoid muscle and the anterior edge of the trapezius, bordering on the external ju- gular vein, there are half a dozen. Between the skin and the parotid gland there are two, one above and the other below. On the submaxillary gland, and at its anterior and posterior extremities, there are eight or nine. It is supposed, by respectable surgeons, that the reputed cases of extirpation of the parotid and of the submaxillary gland, have amounted acta- BLOOD-VESSELS. 29 ally only to the removal of some of these lymphatic glands in a state of enlargement. The deep-seated lymphatic glands are also very abundant; along the course of the great cervical ves- sels, but principally between them and the anterior edge of the trapezius muscle, there are about twenty. Between the lower edge of the thyroid gland and the sternum on the trachea there are four, and this chain is continued downwards towards the heart by the ex- istence of several on the side of the oesophagus, tra- chea, and great blood-vessels. Section III. of the blood-vessels of the neck and head. The Right Carotid Artery is a branch of the arteria innominata, and the left a branch of the aorta; their course differs somewhat at first, the right being more oblique; afterwards the course and distribution are uniform in both. A regular ascent is performed in front of the cervical vertebrae at the side of the oesophagus and pharynx, no branch being sent off till the carotid is near the os hyoides and just below its cornu. Here it divides into two branches of nearly equal size, the internal and external carotids; the first 30 OF THE HEAD AND NECK. is intended for the brain, and the last for the external parts of the neck and head. In the lower and middle part of the neck the carotid is covered by the anterior edge of the sterno-cleido-mastoideus, and at an inch below its bifurcation it is crossed obliquely by the omo-hyoideus muscle. In its whole course it is in- volved with the par vagum, sympathetic and descen- dens noni nerves. Parallel with the larynx the carotid may be felt pulsating very distinctly, being here covered only by the platysma myoides. It is continued in a sheath of condensed cellular membrane common to it, the in- ternal jugular vein and the par vagum nerve. The External Carotid, at the place of bifurca- tion, is interior and anterior to the internal carotid, and it immediately begins to send off branches as follow: 1. The Arteria Thyroidea Superior passes in a meandering direction to its principal destination the thyroid gland, through which it is minutely dis- tributed, anastomosing freely with the other arteries of the same body. In its course it sends off the laryngeal branch, which penetrates to the muscles of the larynx, either between the os hyoides and thyroid cartilage or the thyroid and cricoid. It also sends off some smaller branches to contiguous parts. BLOOD-VESSELS. 31 2. The Arteria Lingualis arises just above the last; it goes very near the cornu of the os hyoides, crossing it obliquely by penetrating the hyo-glossus muscle. At the root of the tongue it sends off a trans- verse branch (the Dorsalis Linguae), and a little further forwards it divides into two branches, one going to the Sublingual Gland (the Ramus Sublingualis), the other distributed through the tongue (the Ranina). 3. The Arteria Facialis arises near and above the other; it is tortuous, passing under the stylo hyoid and the tendon of the digastric muscles. It is much in- volved with the submaxillary gland, to which it sends branches. The submental branch arises from it here, which passes forwards to the symphysis of the jaw, near the exterior margin of the mylo hyoid muscle. The Arteria Facialis mounts over the lower jaw just before the masseter muscle; to the latter it sends a branch; forwards it sends another towards the front of the chin called Inferior Labial. On a line with the corner of the mouth, it sends to the lips the inferior and the superior coronary arteries, which are very tor- tuous and surround the mouth, anastomosing freely with those of the other side. After this the facial artery ascends to the internal canthus of the eye, sending off intermediately a branch to the ala nasi, and another which anastomoses with the inferior orbitar artery; at the internal canthus it $2 OF THE HEAD AND NECK. anastomoses with branches from the ophthalmic and terminates. 4. The Arteria Pharyngea Inferior arises from the carotid opposite to the lingual; it is small, being distributed on the pharynx and sending a branch up- wards through the foramen lacerum to the dura mater. 5. The Arteria Occipitalis is large, arising oppo- site to the facial and sometimes higher up. It crosses over the internal jugular vein and the eighth pair of nerves, passes the base of the cranium under the in- sertion of the muscles going to the mastoid process, and is distributed to the parts lying on the occipital bone, its upper branches anastomosing with those of the temporal artery. Its collateral branches are, one to the dura mater through the posterior foramen lacerum, another to the interior parts of the ear, and a considerable one to the complexus and adjacent muscles of the neck. 6. The Posterior Auris, or Arteria Stylo Mastoidea, arises from the carotid at the lower edge of the parotid gland, and passes backwards and up- wards between the meatus externus and the mastoid process terminating behind the ear. It is distribut- ed principally to the contiguous superficial parts, but BLOOD-VESSELS. 33 one branch goes up the stylo mastoid foramen, being distributed to the tympanum and to the labyrinth. The External Carotid, while dispatching these branches, becomes very deeply situated under the di- gastric and stylo-hyoid muscles, and the inferior end of the parotid gland, afterwards it penetrates the sub- stance of the gland, becoming much involved in it, and sending off several small twiggs. It ascends through the gland and exhibits itself superficially just before the meatus externus, in mounting over the root of the zygoma. When it arrives on a line with the neck of the jaw bone it sends off a very large branch, the internal maxillary, to the parts underneath the ra- mus of the bone. The origin of this branch is to be considered as the termination of the name external carotid, and the trunk is afterwards called temporal. The Arteria Temporalis terminates on the side of the head; while it is still imbedded in the parotid, it sends off the Transversalis Faciei, which crosses the masseter muscle below the Parotid Duct, and is dis- tributed to the contiguous parts. The temporal artery then rises over the zygoma, where a branch leaves it which penetrates the temporal fascia, and is distributed to the muscle, it is the middle temporal artery. The temporal artery having got an inch or so above the zygoma, divides into an anterior and a pos F, 34 OF THE HEAD AND NECK terior branch. The first is distributed forwards on the temple, inosculating with its follow of the other side, and with the facial and the ophthalmic artery. The second is distributed laterally on the parietal re- gion, also anastomosing with its fellow of the opposite side and with the occipital artery. The Arteria Maxillaris Interna can be got at only by removing the ramus of the jaw; it winds around the neck of the inferior maxilla, and proceeds in" a very- tortuous manner to the bottom of the zygo- matic fossa, touching, in its course, the inferior sur- face of the temporal bone. It passes between the in- ternal and external pterygoid muscles immediately after leaving the carotid artery, and sends off, in its course, several branches, generally in the following order: 1. To the cavity of the tympanum through the gle- noid fissure. 2. The lesser meningeal, to the dura mater through the foramen ovale. 3. The greater meningeal, to the dura mater through the for. spinale. 4. The inferior maxillary, to the teeth of the lower jaw through the posterior mental foramen. 5. Two branches to the temporal muscle, the first is the exterior deep, the second the interior deep temporal artery. BLOOD-VESSELS. 35 6. Branches to the pterygoid muscles and to the masseter. 7. A branch to the buccinator and zygomaticus major. 8. The alveolar artery to the great and small mo- lar teeth of the upper jaw. 9. The infra orbitar, through that canal to the ca- nine and incisor teeth and to the cheek. 10. The superior palatine artery through the pos- terior palatine canal to the soft palate. 11. The superior pharyngeal artery to the upper part of the pharynx. 12. The spheno palatine, which is the terminat- ing branch to the internal maxillary artery, and is very minutely distributed to the Schneiderian mem- brane by two trunks, one on the septum of the nose, and the other on its external side. The Internal Carotid Artery, at its commence- ment, is generally dilated like an incipient aneurism; it curves much in getting to the foramen caroticum, and is in contact with the par vagum and sympathe- tic nerves; it sends off nQ intermediate branches. In the canal, it gives a branch to the tympanum, and as it lies on the side of the sella turcica, it gives the an- terior and posterior arteries of the cavernous sinus. Its subsequent history is merged in that of the oph- thalmic and cerebral arteries. The arteries of the lower part of the neck are de- 36 OF THE HEAD AND NECK. rived from the subsclavian, as it is about to get be- tween the scaleni muscles.' The Arteria Thyroidea Inferior, having this origin, passes up obliquely to the thyroid gland be- tween the great vessels of the neck and the vertebrae; in its distribution it anastomoses very freely with the other thyroid arteries. The Vertebral Artery goes into the canal of the transverse processes of the neck at the sixth ver- tebra, and, following its course, enters the foramen magnum occipitis and is distributed to the brain. It is very tortuous at the first and second vertebrae. The Cervicalis Anterior is a small artery of unsettled origin, distributed along the course of the scaleni muscles. It comes frequently from the infe- rior thyroid. The Cervicalis Posterior is also of unsettled ori- gin; it is very tortuous, and runs horizontally across the root of the neck, or the upper part of the thorax to the trapezius muscle and the subjacent ones. It arises either from the subclavian or the inferior thy- roid most frequently. The Veins of the Face and external parts of the Head correspond so nearly with the distribution of BLOOD-VESSELS. 37 the arteries, that they may be considered as having the same course; to undertake the description of them, therefore, would be almost a repetition of what has been said of the arteries. Towards the angle of the jaw they are collected into a common trunk, the ex- ternal jugular (Jugularis Externa), which crosses ob- liquely the sterno-cleido-mastoid muscle under the platysma myoides in the direction of the fibres of the latter, and runs into the subclavian vein just behind the clavicle at the posterior edge of the sterno-cleido- mastoid muscle. Sometimes the external jugular, almost immediately after its formation, joins the internal jugular. On other occasions the facial vein joins the external ju- gular; and the temporal vein, with slight accessions from the side of the face, forms a trunk which de- scends almost vertically under the platysma myoides and outside of the sterno-cleido-mastoideus, and joins the subclavian vein in front of the scaleni muscles. The varieties are, in short, too numerous to recount in this work. The Internal Jugular Vein (Jugularis Interna) may, with propriety, be considered as the great ve- nous trunk of the brain, being a continuation of the lateral sinus. It lies on the outside of the internal and the common carotid arteries, enclosed in the same sheath, descends into the upper mediastinum in con- tact with the pleura, and is joined at the internal 38 OF THE HEAD AND NECK. edge of the scalenus anticus muscle by the subclavian vein. The jugular vein is occasionally much dilated, and in the contractions of the auricle, spreads over the carotid artery. One vein is sometimes much larger than the other. The Upper Thyroidal Veins discharge into the internal or external jugulars, the Lower Thyroidal Veins into the transverse or subclavian veins; some- times a trunk is formed across the upper edge of the sternum from one subclavian to the other, and above the great transverse vein; into this the inferior thy- roidal veins discharge in whole or in part. The va- riety of arrangement is here also too great to admit of a standard description. Section IV. OF THE NERVES OF THE HEAD AND NECK. A minute dissection of these will scarcely be un- dertaken by the young student; to perform it success- fully requires much time, patience, and address; when, by advanced study, these qualities are obtained, the labour of it will be fully compensated by the plea- sure and information it affords. For a very minute dissection a lean subject is indispensable; for a com- mon one, it is less important, and much of the dissec- NERVES. 39 tion may be performed on the subject appropriated to the arteries. The Portio Dura comes out at the stylo-mastoid foramen, is almost immediately afterwards deeply in- volved in the parotid gland, and divides into fasciculi in its substance. Emerging at different points it is distributed very minutely on the side of the face, sending branches to the temple which join those of the supra-orbitar nerve, branches to the cheek which join those of the infra-orbitar nerve, branches to the chin which join those of the inferior maxillary nerve, and branches to the upper parts of the neck which join those of the superior cervical nerves. The distribution of this nerve is too minute to ad- mit of more than a general reference to it. Its branches join each other frequently, forming the net- work called pes anserinus. The dissection of it should be commenced at the stylo-jnastoid foramen, or in the parotid gland, and the skin should be raised only as its branches are exposed; without this pre- caution the dissection will fail. The Trigeminus, or Fifth Pair of Nerves, comes next. Its branches are brought into view by sawing off the ramus of the lower jaw and detaching it en- tirely, observing to leave the pterygoid muscles by cutting close to the bone through their insertions; when the adipose and cellular membrane is then cleared away, the second and third branches of this 40 OF THE HEAD AND NECK- nerve are seen deep in the bottom of the zygomatic fossa. For the distribution of the first or ophthalmic trunk, see the " Auxiliary parts of the eye." The Second, or Superior Maxillary branch of the Fifth, comes out of the cranium through the fora- men rotundum, and is first seen in the upper part of the pterygoid fossa. It immediately sends forwards a branch into the infra-orbitar canal of the upper jaw bone, which passes through it, comes out at the infra- orbitar foramen, and terminates by branches .on the cheek. This is the infra-orbitar nerve which, just be- fore entering the canal, sends off two twigs to supply the three or four last molares, and which forwards sends off the anterior dental nerve to supply the small molar, canine, and incisor teeth. Afterwards, the Superior Maxillary Nerve passes downwards to a level with the spheno palatine fora- men in two divisions; here they unite, form the spheno palatine ganglion, or the ganglion of Meckel, from which proceed the Pterygoid, the Lateral Na- sal, and the Palatine Nerves. The Pterygoid Nerve, retrograding through the foramen of the same name, gets into the cavity of the cranium through the anterior foramen lacerum at the point of the petrous portion of the temporal bone and there divides; one branch joins the carotid artery, (see Sympathetic Nerve,) and the other passing into NERVES. 41 the vidian foramen has a singular course through the ear. (See Chorda Tympani.) The Lateral Nasal Nerve consists of several filaments passing from the spheno palatine ganglion; getting into the nose they are distributed to the pitui- tary membrane of the outside of the nose, and also to the same membrane which covers the septum. One of the branches of the latter makes a long sweep, dips into the foramen incisivum, and, according to Mons. J. Cloquet, forms a ganglion with its fellow near the bottom of the canal. With this ganglion communi- cate branches of the palatine nerve. The Palatine Nerve passes through the poste* rior palatine canal to the roof of the mouth; it there divides into filaments supplying its lining membrane, the soft palate, the uvula, and the tonsils. In its way downwards, it sends several small twigs to that por- tion of the pituitary membrane which covers the in- ferior turbinated bone. The Inferior Maxillary Nerve, or the Third Branch of the Fifth Pair, comes through the foramen ovale into the zygomatic fossa, and divides immedi- ately into two branches, one of which is distributed in minute ramifications to the muscles of mastication, as the pterygoid, masseter, and temporal; it also sends a branch, the size of a knitting-needle, which joins F i2 OF THE HEAD AND NECK the portio dura on the face, and, in order to get to it, adheres closely to the neck of the inferior maxilla. This last branch, from being blended with the portio dura, must, of course, as long as it remains undivided, render nugatory the division of the portio dura for tic doloureux. It is omitted by many respectable anato- mists. The Second Branch of the Inferior Maxillary Nerve passes between the pterygoid muscles and di- vides into two trunks, one of which proceeding to the tongue is the lingual or gustatory nerve, and the other going to the lower jaw bone is the proper Infe- rior Maxillary Nerve. The first in its progress be- tween the pterygoid muscles is joined by the chorda tympani; it there passes above the mylo-hyoid muscle near the duct of Wharton, and advancing to near the end of the tongue is divided very minutely among the papillae. The inferior maxillary nerve enters the posterior maxillary foramen; but while doing so des- patches a branch to the submaxillary gland and the muscles under the jaw; it then continues in a canal in the spongy part of the bone, dismissing ramifications to all the teeth successively. Much of the nerve, how- ever, remains to come out at the anterior maxillary foramen, which is spent upon the contiguous muscles. In order to proceed properly in this dissection of the Nerves of the Neck, the skin must be carefully raised from the sterno-cleido-mastoid muscle- bv NERVES. 43 which means we shall see the spinal accessory nerve emerging from the muscle, and after having given a few branches to it, passing backwards to be distribut- ed on the anterior edge of the trapezius muscle. By detaching the sterno mastoid muscle from its origin and turning it aside, the spinal accessory nerve will be seen coming from the posterior foramen la- cerum where it adheres to the Par Vagum, Glosso- pharyngeal and Ninth pair; and passing obliquely be- hind the internal jugular vein downwards and back- wards, in order to reach the sterno mastoid muscle. At this stage of the dissection a multitude of ner- vous filaments is seen upon the neck going to its muscles, integuments and other parts, and interwoven with its blood-vessels. They form an intricate plexus derived from various combinations of the eighth and ninth pairs, the sympathetic and the proper cervical nerves, the detailed description of which is too elaborate for a dissector's manual. It is best, there- fore, for the attention to be confined to leading trunks. The Glosso-Pharyngeus is a small nerve coming from under the internal jugular vein, adhering to it, and to the other branches of the eighth pair, by con- densed cellular membrane; it passes to the tongue be- tween the stylo-glossus and stylo-pharyngeus muscles, and on the outside of the internal carotid artery. Following the course of the stylo-glossus muscle at 44 OF THE HEAD AND NECK. its internal edge, it gets to the root of the tongue, where it is distributed on its side and middle, and to the papillae maximae. In its course, it sends several branches to the muscles of the pharynx, and to its internal membrane. The Ninth Pair, or the Nervus Hypoglossus, is also very deeply seated, where it emerges from the cranium at the anterior condyloid foramen. Adhering for some distance to the par vagum, by condensed cellular membrane, it abandons the par vagum by get- ting between the internal carotid artery and the in- ternal jugular vein, and crossing them obliquely about half an inch below the glosso-pharyngeal. It descends much lower in the neck than the glosso-pharyngeal, forming a large curve with the convexity downwards. It is the next large nerve below the glosso-pharyn- geal, the order of descent being the lingual branch of the fifth pair first, the glosso-pharyngeal second, and ninth nerve third. In its descent the Ninth nerve winds externally around the external carotid artery, just below the origin of the occipital artery. Here it is below the posterior belly of the digastricus, and the stylo hy- oideus. It then passes forwards somewhat horizon- tally under the external jugular vein towards the root of the tongue, where it is at the side of the hyo-glos- sus muscle a little above the os hyoides, and crossed externally by the stylo hyoideus and the tendon of the NERVES. 45 digastricus. It now ascends on the inside of the mylo hyoideus, and divides abruptly into many ramifi- cations distributed to all the muscles of the tongue, from the space between the genio-hyo-glossus and lingualis muscles. Where the Ninth nerve winds externally around the external carotid, it dismisses the descendens noni, which descends externally along the common carotid, connected with its theca as far as midway between the sternum and os hyoides; here it unites with rami- fications from the first, second, and third cervical nerves, and forms a bow under the sterno mastoid mus- cle. Above this bow the descendens noni detaches branches to the upper parts of the sterno hyoid and thyroid muscles, and from the bow branches proceed to the lower parts of these muscles. The Par Vagum, a famous nerve, is immediately seen on separating the common carotid, and the inter- nal jugular from each other. It lies in the sheath of these vessels at their back part and between them. Emerging from the cranium at the posterior foramen lacerum it is somewhat swollen, adheres to the ninth pair, and to the superior cervical ganglion of the in- tercostal nerve. It leaves them after a short distance, assumes the position, just expressed, and maintains it down the neck till it reaches the upper margin of the thorax. Shortly after quitting the cranium, it sends to the 46 OF THE HEAD AND NECK. middle constrictor of the pharynx, the Nervus Pha~ ryngeus. Just below the pharyngeal nerve, the Laryngeus Superior is sent off, which descends obliquely under the Internal Carotid, and divides at the posterior edge of the thyro-hyoid membrane into an internal and external branch. The former being the largest and above, proceeds between the os hyoides and the thy- roid cartilage under the thyro-hyoideus muscle, to the internal parts of the larynx where it is distributed by minute ramifications to the arytenoid muscles, epi- glottis and lining membrane. The external branch descending, is disposed of by ramifying to the pharynx, to the lower part of the larynx, and to the thyroid gland. In the upper part of the thorax, or the lower part of the neck, the par vagum abandons the common ca- rotid, and passes before the subclavian artery on the right side, and before the aorta on the left. Imme- diately after passing these vessels it divides into an anterior and a posterior trunk, the first being the con^ tinued par vagum, the second the recurrent, or the inferior laryngeal. The Laryngeus Inferior has the same distribution on both sides, but it is to be observed that on the right, it winds around the subclavian artery, and on the left it winds around the arch of the aorta. The nerve is then deeply situated on the side of the trachea and ascends to the larynx, sending branches to the tra- NERVES. 47 chea, the oesophagus and the thyroid gland. It is minutely distributed by terminating ramifications to the small muscles of the larynx, and to its lining membrane. One of its branches at the inferior part of the larynx, communicates with filaments from the laryngeus superior. The Laryngeus Inferior has branches connecting it with the inferior cervical ganglion of the sympa- thetic; the cardiac plexus, and the pulmonary plexus of nerves. i The Nervus Sympatheticus is also on the back part of the great vessels of the neck close to the vertebrae; it is commonly said to be in their sheath; this, however, is a loose if not an inaccurate style of speech, as by passing a knife handle below the sheath and raising it up, it will be seen that the sympathetic is not one of its contents; but, on the contrary, that it is fastened somewhat tightly to the longus colli, and the contiguous muscles by cellular membrane. The sympathetic nerve arises by filaments of the pterygoid and of the sixth nerve, which form a net- work in the carotic canal around the artery; a little above or below the termination of the canal, they unite by two principal trunks to form one nerve. This cord is close to the eighth and ninth nerves, and opposite to the second cervical vertebra, it swells out into the superior cervical ganglion; it then descends, and, op- posite to the space between the fifth and the sixth 48 OF THE HEAD AND NECK. cervical vertebrae, it forms the Middle Cervical Gan- glion, which is much smaller and more irregular than the first. The sympathetic is traced with some diffi- culty from this, in consequence of the numerous branches coming from it; a trunk, however, may be found, as the continuation of it, which passes to the interval between the head of the first rib and the transverse process of the last cervical vertebrae, where another enlargement occurs, denominated Inferior cervical, or First Thoracic Ganglion. The First Ganglion is increased by filaments from the sub-occipital, the first, second and third cervical nerves, and the eighth and ninth. The Second Gan- glion receives filaments from the fourth, fifth and sixth cervical nerves. The Third Ganglion receives filaments from the sixth and seventh cervical, and the first and second dorsal nerves. From these ganglions proceed the cardiac nerves. The Nervus Phrenicus is a small, straight, insu- lated nerve coming principally from the third cervical, but also derived, in part, by filaments from the second and fourth. It is found on the humeral side of the great vessels of the neck, removed a considerable dis- tance from them and lying upon the anterior face of the scalenus anticus muscle. It descends into the thorax between the subclavian artery and vein and within the anterior end of the first rib. Each of the cervical nerves, including the sub-oc- r NERVES. 49 cipital, after its ganglion is formed by the posterior fasciculus of the spinal marrow, exists as a trunk which is joined by the anterior fasciculus of the same. This common trunk gets out between the transverse processes of the cervical vertebrae, and is immediately divided into anterior and posterior branches. The posterior branches are distributed to the muscles and to the integuments which lie on the posterior part of the cervical vertebrae, but the ante- rior branches are variously disposed of. The suboc- cipital and the three first cervical nerves have their anterior branches going principally to the muscles which arise from the transverse processes of the ver- tebrae, and to the skin of the neck. Each of these anterior branches is united by filaments to the nerve above and below it, and a sort of plexus is formed which lies over the levator scapulae muscle. Fila- ments are also sent from the anterior branches of the cervical nerves which join with the spinal accessory nerve, the hypoglossal, the portio dura, the sympa- thetic, and the phrenic in various ways, which are too numerous to be mentioned here. The Third Cervical Nerve sends off a large fila- ment which is the commencement of the phrenic nerve, and this filament is joined by smaller ones from the second and from the fourth. The Axillary Plexus, from which the nerves of the upper extremity are principally derived, arises 50 OF THE HEAD AND NECK. from the anterior branches of the four inferior cervi- cal nerves and of the first dorsal. These branches are much larger than the posterior, and emerge be- tween the anterior and middle scalenus muscles. They send some very small filaments to the lower and middle cervical ganglions of the sympathetic. PART I. CHAPTER II. Section I. Of the Encephalon, or Brain, and Spinal Marrow The best way to get at the Brain, both in public and private dissection, is to make a cut through the scalp across the top of the head from ear to ear, then to turn down the scalp over the face, and behind the back of the neck. The scull cap may then be cut around with a saw carried only through the external table of the scull, just above the tips of the ears and about an inch above the superciliary ridges. With the aid of an iron wedge and a mallet the bone is then easily broken through and separated from the dura mater. Bichat breaks the scull to pieces with a ham- mer and then removes it. The medullary mass placed within the cavity of the cranium is termed in common language Brain. It affords the following parts for separate exami- nation. 1. The Membranes. 2-. The Cerebrum. 52 OF THE HEAD AND NECK. 3. The Cerebellum. 4. The Pons Varolii and the Medulla Oblongata. 1. The membranes are three: The Dura Mater, Tunica Arachnoidea, and Pia Mater. The Dura Mater lies immediately in contact with the bones of the cavity of the cranium, being closely connected to them by blood-vessels and filaments of fibres. It is a white, shining, semitransparent mem- brane consisting of two layers, the internal of which forms several processes. The most conspicuous is the Falx Major, which arises from the centre of the anterior part of the sphenoid bone, from the crista galli of the aethmoid, from under the whole of the middle line of the frontal bone, the sagittal suture, and superior part of the occipital bone as far as the juncture of the limbs of its cross. It is narrow be- fore and broader behind, where it joins with the ten- torium. The next process is the Tentorium, which forms an arch slightly convex above, and crescentic in its general figure. It is connected to the horizon- tal limbs of the occipital cross, to the superior ridge of the petrous bones, and to the posterior clinoid apo- physis on each side. Immediately under the centre of the tentorium, and running towards the occipital foramen, is the Lesser Falx. On each side of the sella turcica is a process of dura mater forming its lateral boundaries. At the anterior edge of the ten- BRAIN AND SPINAL MARROW. 53 torium is the foramen ovale through which the cere- brum and cerebellum unite by their crura. In the angle formed by the reflection of the inter- nal lamina of the dura mater, from the external are some large triangular cavities called Sinuses. The first is the Superior Longitudinal Sinus, which commences by a small beginning near the crista galli. It enlarges by a continual accession of veins from the pia mater and terminates at the occipital cross. On cutting into it we see it lined by a delicate smooth membrane, its sides retained together by many little tendinous chords called the Chordae Willisii, and the veins of the pia mater running into it obliquely forwards so as to produce the effect of valves. In this sinus and under the dura mater near the top of the head are many small bodies of various sizes, the Glandulae, Paccioni, from a line and under to three or four lines in diameter. One of the largest of these bodies, on each side actually protrudes from the surface of the brain through the dura mater, and makes a deep pit into the parietal bone. From the posterior extremity of the longitudinal sinus proceeds on each side in the posterior margin of the tentorium, the Lateral Sinus, terminating in the foramen lacerum posterius. At the inferior edge of the falx major between its duplication, is the Inferior Longitudinal Sinus. And at the junction of the falx major and tentorium is the Torcular Herophili or fourth sinus, formed by the 54 OF THE HEAD AND NECK. inferior longitudinal sinus and a vessel from the inte- rior of the brain called the Vena Galeni. It joins the superior longitudinal sinus at the crucial angle. Around the pituitary gland in the sella turcica is the Circular sinus of Ridley, and surrounding the sella turcica is the Cavernous Sinus. On the occiput and about the petrous bone there are several smaller sinuses which, together with the circular and caver- nous, empty into the lateral. The Dura Mater is supplied with nerves from the fifth pair which are traced with some difficulty. Its principal artery is from the internal maxillary, passing through the foramen spinale, and making the deep arborescent indentations in the parietal bones. There are some other branches derived from the internal carotid and vertebral. The veins accompany the ar- teries, and do not discharge in the sinuses. Under the Dura Mater and covering the whole ex- terior surface of the pia mater, is a delicate transpa- rent membrane with no red vessels in its composition, the Tunica Arachnoidea. It forms an uniform cover- ing, not dipping into the convolutions of the encepha- lon. It may be seen distinctly on the superior surface of the brain like a shining, smooth surface to the Pia Mater, but cannot readily be raised up from it. On the basis of the brain it is a lamina naturally separat- ing itself about the medulla oblongata and the conti- guous parts, from the membranes between which it is placed. The Dura Mater is simply in contact, but does BRAIN AND SPINAL MARROW. 55 not adhere to it;.some anatomists, however, as Bichat, believe that it lines the internal surface of the Dura Mater, having the same reflections as a synovial mem- brane. It is supposed to secrete the lubricating fluid which facilitates the motions of the brain. The Pia Mater is a tender and highly vascular membrane, lying in close contact with the brain, dip- ping into its convolutions and spread over the sur- face of its ventricles in a manner difficult to be un- derstood without dissection. It is much thinner and more delicate in the cavities of the brain than exte- riorly, and seems there more like a vascular net-work than a continuous membrane. It is highly useful in conducting vessels into the substance of the brain by being so extensively spread over its surface, and by dividing them minutely before they penetrate it. Its blood-vessels are exceedingly numerous, being received from the vertebral and internal carotid arte- ries at the basis of the cranium in a manner which will be explained at the end of the chapter. Its veins, it has been said, are inserted into the sinuses of the dura mater, and therefore do not accompany the ar- teries. 2. The Cerebrum fills by far the greater part of the cavity of the cranium, extending from the tentorium and anterior basis of the cranium to its vault. It is par- tially divided above into two equal parts by the falx ma- ( 9 56 OF THE HEAD AND NECK. jor, called the Hemispheres; and below we see that each of these hemispheres is divided into three lobes. The anterior lobe is upon the orbitar process of the frontal bone, the middle lobe in the middle fossa of the basis of the cranium, and the posterior lobe upon the tentorium. Between the anterior and middle lobes there is a deep indentation which prescribes their boundaries, formed by the edge of the little wings of the sphenoid bone; it is the Fossa, or Fissura Mag- na Sylvii. The middle and posterior lobes are not so well separated from each other. The external surface of the cerebrum is arranged into many convolutions which, at a little distance, give it the appearance of intestines. The pia mater, it was said, dips down to the bottom of them and keeps their opposite faces in contact. If a section be made into the brain, it will be seen to consist of matter of differ- ent colours and consistence. The external matter, varying from a line to three or four in depth, is the Cineritious or Cortical, being of a yellowish red co- lour, and somewhat less consistent than the other, and covering all the convolutions. Within the corticul is the Medullary Matter, very abundant in the cerebrum, but not in the same proportion in the cerebellum. It is by a mixture of these two substances that the pro- tuberances to be described afterwards are formed. Proceeding to an examination of the interior struc- ture, by separating the hemispheres, we shall see that just below the edge of the falx major they adhere by the BRAIN AND SPINAL MARROW. 57 pia mater of the opposite sides. Dissect this adhesion through, which brings into view a broad expansion of medullary matter, the Corpus Callosum, extending from the anterior to the posterior edge of the falx, and marked in its centre by two white lines running longitudinally and slightly curved with their convexi- ties towards each other. Between these lines is a fossa called Rapha. Other lines pass laterally and at right angles to the first two. By pulling the hemisphere still more from its fellow, we shall bring into view its edge, which laps over the corpus callosum and is se- parated from it by a fossa six lines deep, running the whole length of the corpus callosum. The hemis- pheres above the corpus callosum must now be re- moved with a sharp knife, which affords a view of the Centrum Ovale of Vieussens, and also of the connex- ion formed between the hemispheres by the Corpus Callosum. The Centrum Ovale is properly speaking the oval nucleus of medullary matter which is left when the cortical is scraped or cut away, but it is most commonly described as the oval disk which is formed by the aforesaid section. The corpus callosum is placed in its middle, and forms the great medullary commissure between its two sides and the roof of the lateral ventricles. By removing the corpus callosum the Lateral Ven- ticles are brought into view. They are very irregular cavities consisting each of three parts, and extending from the anterior to the posterior portions of the he- h 58 OF THE HEAD AND NECK. mispheres. In the anterior lobes are the Anterior Cornua of the ventricles separated only by the Sep- tum Lucidum. In the middle lobes are the Inferior or Middle Cornua passing in a winding direction downwards and forwards; and in the posterior lobes are the Posterior Cornua, also called Digital Cavities. In the fore part of the lateral ventricle is the Corpus Striatum, a long convex body, broad before and com- ing to a point behind; it is cineritious or cortical ex- ternally and medullary within; when scraped the lat- ter looks fibrous. At the posterior part of the corpus striatum is the Thalamus Nervi Optici, a large convex body, the surface of which is medullary and the inte- rior cortical; it has a node on its upper and another on its posterior side, of different sizes in different sub- jects. Between the thalamus and the corpus stria- tum is a streak of matter called Taenia Striata. In the posterior cornu of the lateral ventricle is a rising called Hippocampus Minor, and in the inferior cornu is a larger rising passing to its bottom and increasing in breadth as it descends, called Hippocampus Ma- jor. Its lower end puts on the appearance of a claw, being called, from that cause, Pes Hippocampi. A considerable part of the Thalami Nervorum Op- ticorum is concealed by the Fornix, a triangular arched body of medullary matter, extending from their anterior to their posterior extremities, being nar- row before and broad behind. It commences for- wards by two crura which are very much curved BRAIN AND SPINAL MARROW. 59 with their concavity backwards, and arise deeply from the sides of the thalami near their union with the cor- pora striata. These crura come afterwards into con- tact, increase much in breadth, conceal the thalami, and form a triangular membrane which posteriorly is lost in the back of the corpus callosum and the hip- pocampi majores. The angle formed by the back and lateral margins is elongated and accompanies the hip- pocampus major for some distance, consisting of a thin crus which is easily demonstrated by raising it on the knife handle. It is called Corpus Fimbriatum, or Taenia Hippocampi. The under surface of the fornix is called Lyra. Between the lateral ventricles, at their fore part, is fixed the Septum Lucidum, connected above to the corpus callosum, and below to the fornix. It con- sists of two laminae with a cavity between them at their fore part, called occasionally the fifth ventricle. To get a good view of the septum lucidum, it should be examined as the corpus callosum is raised up. In many subjects, particularly when there has been a small dropsical effusion into the ventricles, the sep- tum looks like a continuation of the middle of the fornix, a lamina of it being contributed by the inter- nal margin of each crus. Under the fornix and lining the cavities of the la- teral ventricles, as well as the other ventricles, is placed a very delicate reflection of pia mater with many vessels in it, but so very thin that it can scarcely 60 OF THE HEAD AND NECK. be raised up as a perfect membrane. This mem- brane gets into the lateral ventricles from the fossa of Sylvius and under the back of the corpus callosum. Along the hippocampus major and the exterior mar- gin of the fornix, on each side, is placed a fold of it quite loose and floating, consisting of a great congeries of small veins. This fold is the Plexus Choroides, which, becoming smaller anteriorly, dips under the anterior crus of the fornix, and its veins unite into a large trunk which runs under the fornix to terminate posteriorly in the vena galeni. That portion of the pia mater lying under the fornix and bounded on each side by the plexus choroides, is called the Ve- lum Interpositum. The fornix should now be raised with the velum interpositum, by cutting through its anterior crura and turning it backwards, which gives a more per- fect view of the thalami. From these bodies on the opposite sides being in contact, a kind of junction is formed by their convexities called the Commissura Mollis. Anterior to this junction is a triangular space called Vulva. It is here that the lateral ventri- cles communicate, under the anterior crura of the fornix, with the third ventricles. This communica- tion is called the Foramen of Monro. Behind the commissura mollis is a similar triangular space the Anus. The third ventricle is brought fully into view by separating the thalami, and we shall find that is formed of the space between them. At its lower BRAIN AND SPINAL MARROW. 61 front part is an open way leading to the basis of the brain, the Iter ad Infundibulum, and at its posterior part is the aqueduct of Sylvius, or the Iter e Tertio ad Quartuum Ventriculum. Situated at the posterior part of the thalami, are the Tubercula Quadrigemina, or Nates and Testes, the former being above. They are each about three or four lines in diameter, consisting of medullary and cineritious matter, and constitute a means of commu- nication between the cerebrum and cerebellum by being united to the valve of the brain, which is in- serted into their lower part. The Pineal Gland, a small oval cineritious body, is found on the top of the nates. It is commonly four lines in its longest dia- meter, and contains a small quantity of calcareous matter feeling and looking like fine sand. It is, how- ever, occasionally collected into one or more irregu- lar masses a line in diameter. This sandy matter is called Acervulus Cerebri. The pineal gland is situ- ated between the nates and the back of the fornix being closely connected with the under surface of, and surrounded by, the velum interpositum, so that, most frequently, when this membrane is raised along with the fornix, the pineal gland is torn from its place. If we are careful to avoid this accident, we shall find, passing along the upper edge of the thalami, on each side, above the commissura mollis, a medullary streak which goes from the pineal gland to the anterior crus 62 OF THE HEAD AND NECK. of the fornix. It is the Pedunculus of the Pineal Gland. At the anterior part of the third ventricle, just be- fore the crura fornicis, and seen between them at their lower part where they diverge, is the Commissura An- terior, a medullary line passing from one thalamus, near the corpus striatum, to the other. At the back part of the third ventricle, just under the tubercula quadrigemina, is the Commissura Posterior passing in the same way from one thalamus to the other. By cutting off the posterior lobes of the cerebrum, removing the tentorium, and dissecting away the pia mater just behind and below the tubercula quadrige- mina, we get a good view of the valve of the brain, which is seen to pass up as a broad lamina of me- dullary matter an inch wide from the central part of the cerebellum to the inferior portion of the testes. By passing a probe from the third ventricle through the aqueduct of Sylvius, it will be seen how this valve forms the roof of the fourth ventricle. It will then also be observed to be thinner in its middle than on either side. The further examination of the Encephalon should be prosecuted by detaching it from the basis of the cranium and turning it out, the nerves being left as long as possible, and the spinal marrow also. The Cerebellum is now seen fully, and one is struck with the difference between its size and that of the Cere- brum, as it occupies only the space between the ten- BRAIN AND SPINAL MARROW. 63 torium and the posterior fossa of the basis of the cra- nium. It is divided into two hemispheres or lobes by the falx minor. Though covered by the same mem- branes, its appearance differs somewhat from that of the cerebrum in consequence of its having no con- volutions. In their place is substituted longitudinal fissures separating its surface into laminae, which pass for the most part horizontally and penetrate to very different depths, from four lines to more, thereby in creasing the surface for the entrance and exit of the vessels. The upper surface of the cerebellum is slight- ly convex corresponding with the concavity of the tentorium. The under surface has a double convex- ity corresponding with the double concavity in the inferior part of the occipital bone. And at the place where the under and upper surfaces meet anteriorly on each side of the crura, is an oblong rounded eleva- tion which, from the transverse fissures in it and its shape, is like a grub worm, and called therefore Ver- mis. The upper central part of it, just above the fourth sinus, is also called vermis. When the cerebellum is cut into, its substance is seen to be firmer than that of the cerebrum, and the cortical matter bears a more considerable proportion than in the cerebrum, constituting nearly a half. The medullary being found principally in its centre, it sends off processes in every direction into the cor- tical. From this circumstance all vertical sections made into the cerebellum will result in giving an arbo- 64 OF THE HEAD AND NECK. rescent outline to the medullary matter. Hence the name of Arbor Vitae, which is merely expressive of this arrangement without designating any particular part of it. The two Crura of the cerebellum pass from its medullary portion, being in fact a mere con- tinuation of it, one on each side, separated from the other by the fourth ventricle; and they are inserted into the posterior upper part of the Pons Varolii. The Brain, when inverted, shows the following parts as uppermost: The anterior and middle lobes of the cerebrum, the two lobes of the cerebellum, the Pons Varolii and the Medulla Oblongata. The Pons is between the anterior part of the ce- rebellum and the posterior part of the middle lobes of the cerebrum. It is nearly spherical on its inferior surface, and about sixteen lines in diameter, divided into two halves by a middle longitudinal fissure with transverse ridges passing from it on each side. In the substance of the Pons or Tuber Annulare is much cortical matter, arranged into striae running in differ- ent directions. The tuber annulare is formed of the crura cerebri and cerebelli. The latter have been de- scribed; the former two arise from the medulla of all the lobes, make their first appearance at the back of the anterior and between the middle lobes; their in- ternal margins touch; they pass backwards to be con- nected with the anterior superior part of the tuber, and are lost in its substance. The crura cerebri are formed of a mixture of medullary and cineritious mat- BRAIN AND SPINAL MARROW. 65 ter; the latter predominates in one part, and from its particular colour is called Locus Niger. The Pons Varolii, thus constituted by the blending of the sub- stance of the four crura, is fixed upon the posterior part of the body of the sphenoid bone and on the cu- neiform process of the os occipitis. The Medulla Oblongata is that portion of en- cephalic substance between the Pons and the supe- rior margin of the first cervical vertebra. Arising from the back of the former, it swells considerably almost immediately, and then tapers down gradually to form the commencement of the spinal marrow. There is - a circular indentation defining its boundaries above with the Pons, but below there is none. A longitu- dinal fissure on its fore part divides it equally. On each side of this fissure above is an oblong eminence tapering to a point below, and disappearing gradually, called Corpus Pyramidale. On the outer side of that again, and separated from it by a fissure on the side of the medulla oblongata, is an ovoid and still more pro- minent convexity, but not so long, called Corpus Oli- vare. And on the outside of this is another and smaller eminence, the Corpus Pyramidale Laterale, or Corpus Restiforme. The Medulla Oblongata consists of me- dullary matter externally, and cineritious internally. By lifting it up from the cerebellum and dissecting away the tunica arachnoidea and pia mater, a good view may be got of the Fourth Ventricle of the brain, i 66 OF THE HEAD AND NECK. which is closed below and separated from the spinat canal by these membranes. It will now be easy to understand that the parietes of the fourth ventricle are formed by the valve of Vieussens and by the ce- rebellum above and posteriorly, by the pons varolii anteriorly, by the Medulla Oblongata below, and by the crura cerebelli laterally. The posterior face of the Medulla is marked by an arrangement of its sur- face corresponding in some measure with the slit and nib of a writing pen, from which it has the name of Calamus Scriptorius. Between the Crura Cerebri at their anterior part are two small round bodies, three lines thick, in con- tact with each other; they are the Corpora Albican- tia or Eminentiae Mammillares. They are placed in a cineritious substance, the Pons Tarini, forming with them the floor of the third ventricle. The Infundibulum is a flattened funnel-shaped tube alluded to in the account of the third ventricle, but best seen in this period of the dissection. It is placed just before the corpora albicantia, and passes from the third ventricle to the pituitary gland, having its apex in contact with the latter, and its broad part opening into the ventricle. It is impervious at its apex. It is cineritious externally, which gives it a red cast, and medullary internally. The Glandula Pituitaria occupies the sella tur- BRAIN AND SPINAL MARROW. 67 dca, and is somewhat spherical, being about six or seven lines in diameter. Its structure is firm and re- sisting, formed of a tough cineritious matter exter- nally, and of a kind of medullary internally. It is al- most concealed by a close reflection of dura mater over it. There are nine pairs of nerves going from the ba- sis of the brain. I. The Olfactory, appropriated to the nose, arise by three striae from the corpora striata, and make their appearance on the back and inferior part of the anterior lobes. Their structure is soft and pulpy, and they are protected from the weight of the brain by being deposited in a triangular groove formed by a convolution. They swell out into bulbs at their fore part on the sides of the crista galli, and perfo- rate the cribriform plate.of the oethmoid bone by nu- merous filaments. They get a coat from the dura mater which gives them great strength, and are then distributed as mentioned in the account of the nose. 2nd Pair, or the Optic Nerves, are of considera- ble magnitude, and differ somewhat in their texture from the other nerves in consequence of having a ge- neral investment of pia mater before it surrounds their particular fasciculi, and also from having more medullary matter in them. They arise from the pos- terior parts of the thalami and make their appear- 68 OF THE HEAD AND NECK. ance between the middle lobes and the crura cerebri. There is a very close intertexture of the nerves of the opposite sides just before the infundibulum, so that it is a questiqn whether they decussate each other, or simply unite. They pass to the ball of the eye, being the nerves of vision, through the foramina optica and are expanded into the retina. 3rd Pair, or the Motores Oculorum, arise from the inner margins of the crura cerebri near the pons varolii by several filaments. They pass outwards and penetrate the dura mater near the posterior cli- noid process, and traversing the upper part of the ca- vernous sinus they get into the orbits through the fo- ramina lacera. They are distributed to the mus- cles of the eye, except the trochlearis and rectus ex- ternus, and contribute to the ophthalmic ganglion. 4th Pair, or Trochleares. Each arises by two filaments, which quickly unite, from the valve of Vieussens just below the tubercula quadrigemina. It is not larger than a common sewing thread, and makes its appearance at the anterior lateral margin of the pons varolii. It penetrates the edge of the tentorium not far from the entrance of the third nerve, and run- ning in an investment of dura mater through the ca- vernous sinus at the outer side of this nerve, it after- wards crosses it above, and, getting into the orbit BRAIN AND SPINAL MARROW. 69 through the foramen lacerum, is appropriated to the trochlearis muscle. 5th Pair, or Trigemina, the largest of all. Each arises from the side of the tuber annulare just where it is blended with the crus cerebelli, by two portions, the anterior being smallest. Their fibres are collect- ed into one cord, which passes into a canal of the dura mater, lying on the anterior part of the petrous bone. It is not connected to the canal except at the lowest part, where it receives a coat from it. The nerve is then expanded like a fan, being divided into seventy or eighty filaments. At their circumference is a brownish substance, the ganglion of Gasser, from the convexity of which pass off three great divi- sions, named from their appropriations. The Oph- thalmic nerve goes out of the cranium at the foramen lacerum of the orbit, the Superior Maxillary at the foramen rotundum, and the Inferior Maxillary at the foramen ovale. 6th Pair, or Motores Externi. Each nerve arises from the commencement of the medulla oblon- gata between the tuber annulare and corpus pyrami- dale. It passes forward through the dura mater, at _ the cavernous sinus, in a canal, on the inside of the fifth nerve, and lying between this nerve and the ca- rotid artery, it detaches one or more filaments to form the commencement of the sympathetic nerve, which 70 OF THE HEAD AND NECK. accompanies the carotid artery through the carotid canal to the neck. The trunk of the motor externus then gets into the orbit through the foramen lacerum and is appropriated to the rectus externus muscle of the eye. 7th Pair, composed of two nerves, Portio Mollis and Portio Dura. The first arises from the poste- rior face of the medulla oblongata, where it forms the fourth ventricle, being separated from its fellow of the opposite side by the slit of the calamus scriptorius. The second, or portio dura, arises from the place of junction for the pons, medulla oblongata, and crus ce- rebri. A third nerve which, in a little distance, joins the dura, and is a mere fibril called Portio Media, arises near the latter. The seventh nerve, thus con- stituted of a bard and of a pulpy portion, dips into the meatus auditorius internus. The mollis goes to the ear being spent on the labyrinth;,the dura, passing along the aqueduct of Fallopius, gets out at the stylo-mas- toid hole and goes to the face. 8th Pair, consists of three portions having different destinations: The Glosso-Pharyngeal, Par Vagum or Pneumo-gastric, and the Spinal Accessory nerve of Willis. The two first arise near each other from the Medulla Oblongata at its side, behind the corpora oli- varia, at the Corpora Pyramidalia Lateralia. The Glos- so-Pharyngeal is before the other, and consists of one BRAIN AND SPINAL^ MARROW. 71 chord. The Par Vagum is composed of several fasci- culi having a flattened appearance, which afterwards unite together. The Spinal Accessory has a remark- able origin from the Medulla Spinalis, occasionally as low down as the seventh cervical nerve, between the anterior and posterior fasciculi. Its fibres succes- sively form a round trunk, assisted also by contribu- tions from the side of the Medulla Oblongata, which trunk, passing up the spinal canal and into the cavity of the cranium through the foramen magnum, is asso- ciated with the nerves just mentioned. They all pass out of the cranium at the posterior foramen lacerum, anterior to the internal jugular vein, separated from it by a spine of bone and by a process of dura mater. The distinction of the nerves from each other is also kept up here by processes of dura mater between them. They adhere on the outside of the cranium and then part for their different destinations; the Glosso-pharyngeal for the tongue and pharynx, the Par Vagum for the lungs and stomach, and the Spi- nal Accessory for the muscles and integuments of the neck. 9th Pair, or Linguales. Each nerve arises from the side of the medulla oblongata at the groove be- tween the corpus pyramidale and olivare, by three or four fasciculi. These fasciculi unite into a trunk, ^ which gets from the cranium through the anterior condyloid foramen, and is distributed to the tongue 72 OF THE HEAD AND NECK. OF the medulla spinalis. This is a continuation of the medulla oblongata, and passes from it to the second vertebra of the loins, where it terminates in a conical point, being contain- ed in the vertebral cavity. It has the same number of membranes with the Brain; that is the Dura Ma- ter, Tunica Arachnoidea and Pia Mater. The Dura Mater resembles very much the same membrane of the brain except that it has more elas- ticity; it does not adhere closely to the bone, but lies loosely enveloping the spinal marrow and nerves un- til it touches the foramina through which the latter pass out. The spinal cavity is lined its whole length by a ligamentous membrane which strengthens the articulations of the vertebrae, being in close contact with them. Between this membrane and the dura mater is interposed a soft watery and vascular fat, which forms a sort of bed for the dura mater and fills up many of the inequalities between the two mem- branes. At the egress of the dura mater from the cranium just around the foramen magnum, it adheres closely to the ligamentous lining, but is loose all the rest of the way down with the exception stated. The Pia Mater is in close union with the Medulla Spinalis, and is commonly to be found with its veins injected in the same way with the pia mater of the brain: it is however not quite so vascular as the for- BRAIN AND SPINAL MARROW. 75 mer. The Tunica Arachnoidea lies loosely between the dura and pia mater, preserving its character of extreme tenuity and transparency; it may be elevated any where with a pair of forceps, and continues downwards to the end of the spinal cavity connecting the fasciculi of nerves together. On each side of the spinal marrow running between the anterior and posterior fasciculi of nerves, is a narrow semitransparent band called Ligamentum Denticulatum, fixed beneath the tunica arachnoidea, and connected to the pia mater by cellular substance. It is first observed arising from the dura mater at the occipital foramen, and then passing below, between the lateral fasciculi of nerves, is united to the pia ma- ter and to its fellow at the conical termination of the medulla spinalis. The ligament from each side being thus incorporated with its fellow, they descend in the form of a single round chord which is attached to the os coccygis, and resembles a continuation of the me- dulla spinalis. As the ligament above passes between the anterior and posterior fasciculi of nerves, it de- taches little round tooth-like processes, fixed to the inner surface of the dura mater, and carrying the tu- nica arachnoidea along with them. From these pro- cesses it derives its name. The medulla spinalis being a continuation of the medulla oblongata, like it consists of two kinds of matter, cortical and medullary; the latter being placed externally. It has anteriorly and posteriorly a fissure K 74 OF THE HEAD AND NECK. penetrating almost to its centre and extended its whole length, which divides it into two equal parts. These halves are again divided each into anterior and poste- rior portions by a long lateral fissure which is not so deep as the other. These several divisions of the spi- nal marrow being connected by the internal cineri- tious matter, when a horizontal cut is made, the latter puts on a crucial appearance. From the anterior and posterior sections of the spinal marrow flat fasciculi of nerves proceed, which penetrate the dura mater separately and derive a coat from it. This coat exists for some distance as a sheath, united to the nerve by cellular substance, but is closely fixed to it near the foramen of the spine. The posterior fasciculus, at this place, forms a gan- glion which sends out a nerve at its fore part; this nerve, just at its origin, is united to the anterior fas- ciculus, and thus forms the commencement of the spinal nerve. As soon as the spinal nerve clears the foramen in the bones, it sends branches backwards to the muscles of the spine, others forwards to join the sympathetic, and the middle trunk goes accord- ing to the part of the body to be supplied. There are thirty pairs of spinal nerves, including one which passes between the occiput and first ver- tebra called Sub-occipital; seven to the neck, twelve to the back, five to the loins, five to the sacrum. The nerves of the neck, from their origin to the in- tervertebral holes, are short and nearly horizontal: BRAIN AND SPINAL MARROW. 75 those of the back pass obliquely downwards, increas- ing in obliquity as they descend. The lumbar and sacral nerves are extremely oblique, the lowest being almost vertical; they arise very much in a cluster close to each other, and form, in the dura mater, the Cauda Equina. of the blood-vessels of the brain and spinal MARROW. The brain is supplied by the internal carotids and the vertebral arteries. The former, passing in a very tortuous manner through the canal in the temporal bone, appear in the cavernous sinus at the sides of the anterior clinoid processes. They there send off, each anteriorly, the ophthalmic artery through the optic foramen, and, in a short space afterwards, a branch which goes backwards, the Arteria Commu- nicans, to join the posterior artery of the cerebrum; the main trunk is continued into the fossa of Sylvius, and forms the Arteria Media Cerebri, and from this is sent off the Arteria Anterior, which supplies the anterior lobe and the corpus callosum. The ante- rior trunk communicates by a short transverse branch with its fellow. The vertebral arteries come up through the fora- men magnum and unite with each other at the pos- 76 OF THE HEAD AND NECK. terior part of the pons varolii, forming the basilar trunk. The Basilar artery divides anteriorly into two branches which run to the posterior lobes of the brain; they constitute the Arteriae Posteriores Cerebri. From the basilar near the vertebrals, arises, on each side, a trunk, the Arteria Inferior Cerebelli, and from its anterior part the Arteria Anterior Cerebelli. The circle of Willis is formed by the anterior bifurcation. of the basilar, connected to the internal carotid by the Arteriae Communicantes. The veins of the brain have been mentioned as all emptying into the sinuses of the dura mater. The arteries of the spinal marrow are derived from the vertebrals, intercostals, and arteries of the neck. The veins accompany the arteries forming sinuses on the outside of the dura mater, one on each side, which empties into the occipital and lateral sinus, anastomosing; however, very freely with a plexus of veins which surrounds the spinal column. BRAIN AND SPINAL MARROW. 77 Section II. of the anatomy of the brain and spinal marrow, according to gall and spurzheim. I have thought proper to add this chapter on ac- count of the recent interest which has been felt in Philadelphia, for the peculiar tenets of these gentle- men, and because I am persuaded that their's is a very improved and simplified mode of studying the anatomy of the brain, and of the nervous system. Whatever may be the ultimate fate of their physiolo- gical opinions, it should have no influence on their anatomical observations, as the two subjects are in their nature intrinsically distinct, and ought not to be considered in any other manner. One is an obvious matter of fact, and, for the most part, as susceptible of demonstration as the contents of the thorax; the other rests on a more uncertain foundation, is there- fore liable to error, and should not yet be considered as having passed its period of infancy, and the ordeal of public criticism. The brain and spinal marrow, these gentlemen say, consist of two kinds of substance, cineritious and fibrous. The first is found abundantly on the surface of the brain, within its substance at particular places, and diffused through the spinal marrow. Its consist- 78 OF THE HEAD AND NECK. ence is pulpy and gelatinous, varying in degree in dif- ferent subjects, and of a yellowish red colour for the most part. It is extremely vascular, in consequence of which, some anatomists have considered it to con- sist entirely of blood-vessels, but Albinus and Soem- mering have both proved by injections, that there is some other substance which is probably secreted by them. This substance is the matrix or soil of the nervous fibres constituting the other part of the brain. A very general error has prevailed in regard to what is called the medullary portion of the brain; some consider it to be solid, others that it consists of hollow tubes, some that it has no vessels, others that it consists entirely of them. The fact is that it is fibrous, which may be demonstrated by scraping it from the centre to the circumference in the direction of its fibres, by boiling its convolutions in oil, or ma- cerating them in nitric or muriatic acid diluted with alcohol. For these reasons Messrs. Gall and Spurz- heim reject the term Medullary as communicating a false idea, and call it the Nervous Mass. The Spinal Marrow in worms and caterpillars, consists of a series of ganglions united to each other by nervous branches, giving it the form of a chord with small tubercles of various shapes and sizes. For every superficial ring or segment of these animals, there is one of these knots or ganglia for the origin of nerves, and the size and number of the nerves BRAIN AND SPINAL MARROW. 79 emanating from one of these ganglia, will always be in proportion to the size of the ganglion itself. In fishes, amphibia, and birds the same arrangement pre- vails, only in not so distinct a shape, the ganglia be- ing nearer to each other, and with the uniting bands forming a chord of more equal size, swollen how- ever where large nerves go off. The same knotted condition is observed in the mammalia and in man, but not so evidently in the latter; one may, however, be convinced of it by removing the spinal marrow, de- taching the tunica arachnoidea, and observing the pro- file between the eye and the light. The outline is every where more or less waving, corresponding with the origins of the nerves, the largest swellings being where the nerves of the extremities go off, which are the largest nerves of the medulla spinalis. The spinal marrow, for these reasons, is enlarged from the third vertebra of the neck to the first dorsal; it is then gra- dually diminished to the tenth dorsal; it afterwards enlarges to the first lumbar vertebra, and forms an elongated point where it terminates. In the medulla spinalis are two fissures going in a vertical direction, one in the middle before, and the other in the middle behind, which divide it into two equal parts or halves; the first is wider and more visi- ble, the second is deeper. There are no lateral ver- tical fissures, as some anatomists assert.* At the bot- * See p. 74 80 OF THE HEAD AND NECK. torn of the anterior fissure the two halves of the spi- nal marrow are united by transverse fibres which pass from side to side, forming a layer, and at the bottom of the posterior fissure there is also a corresponding layer of fibres uniting the two halves, but passing longitudinally. The medulla spinalis is medullary or fibrous exter- nally, and cineritious or cortical within. The cineri- tious substance forms a distinct arch in each half, which has its concavity laterally, its two extremities will of course be before and behind. The fasciculi of nervous fibres follow the course of the ends of these arcs from within outwards, some coming out before and others behind; the consequence of which is, that there are on each side two rows of nervous fibres, an anterior and a posterior. The posterior fas- ciculi are the larger, from which cause, probably, it is that the posterior fissure penetrates more deeply. The Encephalon is considered by all anatomists to consist of Cerebrum or Brain, and of Cerebellum or little Brain, each of which is formed of two sym- metrical halves called Hemispheres. Besides which there exist the Pons Varolii and the Medulla Oblon- gata, till lately considered as emanations from the Ce- rebrum and the Cerebellum. On each side of the Medulla Oblongata there are three protuberances; the most anterior is the Corpus BRAIN AND SPINAL MARROW. 81 Pyramidale, just behind it is the Corpus Olivare, and behind it again is the Corpus Restiforme; these pro- jections being named from their exterior configura- tion. The medulla oblongata consists of cortical and fibrous or medullary matter. The latter is composed of fasciculi which may be traced into the brain above, and into the spinal marrow below. Messrs. Gall and Spurzheim consider the cerebral mass to arise from these fasciculi instead of the latter coming from the cerebral mass, as is most commonly taught and believed. The corpora pyramidalia, like the other eminences, are fibrous, and their fibres arise in a pe- culiar manner from the lower part of the medulla ob- longata. This peculiarity consists in the fibres of the right corpus pyramidale arising from the left side of the medulla oblongata, and the fibres of the left corpus pyramidale arising from the right side of the medulla oblongata. These fibres decussate each other an inch and a quarter below the pons varolii, sometimes in single bands, but commonly by an in- tertexture of three, four, or five fasciculi from each side. When traced, their origin is found to be in the cortical substance of the lower part of the medulla oblongata. This arrangement is readily seen by stripping off the pia mater and tunica arachnoidea, and then separating the two sides of the fissure in front of the medulla oblongata. This peculiarity in the origin of the pyramids is supposed to explain the fact of blows on one side of L 82 OF THE HEAD AND NECK. the head paralysing the opposite side of the body, as the sa;ne fibres are continued from the origin of the pyramids to the part of the brain which is injured in these cases. In regard to the other portions of the medulla oblongata, the fibres of which they consist have no such arrangement, but arise fairly on the side to which they belong, and they are continued into the cerebral mass above and communicate with the me- dulla spinalis below. THE CEREBELLUM. The Cerebellum consists of two lobes or hemis- pheres separated in part by a fissure, which makes them very distinguishable from each other. By open- ing this fissure behind we get a view of another or third part of the cerebellum, called by many anato- mists Vermes, but by G. and S. the Fundamental Portion. They are induced to give it this name as it expresses in a measure a fact of some importance, viz. that it always exists in animals that have a cere- bellum, whereas, the lateral parts or lobes do not. Fishes and reptiles are in the latter predicament, but all warm-blooded animals, with man at their head, have the lobes. In man the cerebellum is more complicated and perfect, nevertheless, a constant uniformity is observ- ed in all animals in regard to its origin from the me- dulla oblongata. In the interior of the medulla ob- BRAIN AND SPINAL MARROW. 83 longata on each side, within the corpus restiforme, an accumulation of cineritious substance is observed from which springs an elementary chord of fibrous matter. This chord increases as it ascends towards the cerebellum, and near the latter is covered by the auditory nerve and its ganglion. These should be carefully scraped away; we then see the fasciculus of fibres entering into the interior of the hemisphere of the cerebellum. Proceeding two or three lines, the fibrous chord meets with a collection of cineritious matter of an oval shape with serrated edges, called Corpus Dentatum. The fibres become so blended with this body, that it is impossible to pursue them in any determinate course. The corpus dentatum is considered as a ganglion or accumulation of cineri- tious substance, for the purpose of giving origin to more fibres in the cerebellum. Accordingly several new fasciculi of medullary or fibrous matter arise in it, and ramify in different directions towards the periphery of the cerebellum. Wherever a large rami- fication of fibres departs from it, the quantity of cineritious substance about their root is increased, hence results the fringed or serrated margin. That the corpus serratum is a pabulum for the fibrous structure of the cerebellum, seems proved by the fact, that the greater number of viviparous animals have the cerebellum proportionably smaller than man, and in them the corpus is so little developed that they are said by some to be destitute of it. 84 OF THE HEAD AND NECK The Corpus Dentatum detaches inwardly a large branch which contributes, with a corresponding one from the other side, to form the Vermes, or the Fun- damental Portion of the Cerebellum. In the vermes, the fibrous or medullary matter radiates by seven branches towards its circumference, their extremities and subdivisions being covered by cineritious mat- ter. The corpus dentatum also sends off other branches which go upwards, downwards, and outwards towards the periphery of the hemisphere, which expand into horizontal layers, and have their peripheral extremi- ties covered with the cineritious substance. Such as are nearest to the middle of the cerebellum are longest, and the others gradually decrease in length as they are nearer the place where the original chord entered the corpus dentatum. If the cerebellum be cut vertically through the middle of the corpus den- tatum, eleven principal branches are found proceeding from it; but this number diminishes if the cut be made near the circumference of the cerebellum. It is this arborescent arrangement which, resembling the Thuya, or Tree of Life, gives occasion to the name Arbor Vitae. " Horizontal or transverse cuts of these branches or leaves present only a white substance; therefore, anatomists are wrong in maintaining that the quantity BRAIN AND SPINAL MARROW. 85 of the cineritious mass is more considerable in the cerebellum than in the brain." COMMISSURES OF THE CEREBELLUM. A description of fibrous matter exists in the cere- bellum which cannot be traced, either to the primi- tive fasciculi from the corpora restiformia, or to the new fibres derived from the corpus dentatum. These fibres come from the cineritious matter on the surface of the cerebellum, pass in various directions through the diverging fibres; but always so as to converge to- wards the anterior external margin of the cerebellum, where they form a large and thick layer of fibrous matter. The anterior fibres cross in front, but the middle and posterior pass transversally through, the longitudinal bands of the tuber annulare which are distributed through the hemispheres of the cerebrum; and these transverse fibres, from the opposite sides of the cerebellum, unite, with their congeners, in the middle vertical line of the pons varolii. The pons varolii is, therefore, the place of union for the fibrous structure of the two hemispheres of the cerebellum, and as such is called, by M M. Gall and Spurz- heim, the Great Commissure of the Cerebellum. Considerable light is thrown upon this subject by comparative anatomy, for this great commissure has its dimensions always in strict proportion to the de- S6 OF THE HEAD AND NECK. velopment of the lateral parts or hemispheres of the cerebellum. In the mammalia, as the lateral parts of the hemispheres are small, the tuber annulare is small. In fishes, reptiles, and birds it does not ex- ist at all, because they have no hemispheres to the cerebellum. On the contrary, in man, the hemis- pheres of whose cerebellum are so large, the tuber annulare is remarkably broad and prominent, so much so as to conceal the origins of several nerves which are visible in other animals, and, therefore, to assume fallaciously the appearance of giving origin to them. Although such animals as are destitute of hemis- pheres are without the great commissure of the ce- rebellum, yet as they all have the fundamental por- tion, so they have a Lesser Commissure belonging to it. This commissure is formed of the fibres which come from the upper and lower parts of the funda- mental portion, and join each other in constituting the Valvula Cerebelli, or the Valve of Vieussens, which runs upwards and forwards to join the Infe- rior Tubercula Quadrigemina. This primitive com- missure of the cerebellum forms, in common descrip- tion, the roof of the fourth ventricle. i ) BRAIN AND SPINAL MARROW. 87 THE CEREBRUM. The cerebrum is derived from the corpora pyra- midalia under the following circumstances. As the pyramids are about entering the pons varolii, they contract so as to give the appearance of a neck. The pons varolii has a considerable quantity of cineritious substance in it; the fibres of the corpora pyramidalia, in passing through, are divided into several fasciculi which derive an increment from the cineritious mat- ter, some of the fibres being disposed in layers and others interwoven with transverse chords coming from the cerebellum. Besides the filaments from the cor- pora pyramidalia, others arise from the posterior part of the medulla oblongata and from the corpora oliva- ria to penetrate into the pons varolii. The several fas- ciculi thus formed from the different points of the me- dulla oblongata by passing through the cineritious substance of the pons varolii are so reinforced and multiplied, that on issuing from the latter they form the pedunculi or crura of the brain. And in man the inferior or pyramidal fasciculi receive the greatest accession of new fibres; they, therefore, form two- thirds of these crura. In order to see the course just described of the fibres of the medulla oblongata, remove its membranes and those of the pons, and make an incision one line deep through the front of the pons from the crus of the cerebrum to the base of the corpus pyramidale of 88 OF THE HEAD AND NECK. the same side. With the handle of a scalpel intro- duced to the bottom the incision scrape or push the surface of the pons towards the crus of the cerebellum on the one hand, and towards the middle line of the pons on the other. We thus obtain a distinct sight of the transverse medullary fasciculi constituting the anterior superficial layer of the pons, and when all these are removed we also see plainly the longitudinal fibres coming from the pyramidal bodies; by scraping still deeper more of the fibrous structure of the tuber annulare is brought into view. The anterior and external fasciculi of the crura of the cerebrum are derived from the continuation and the successive increase of the primitive pyramidal bundles, or the corpora pyramidalia. The incessant reinforcement of the corp. pyramid, is produced by their meeting continually in the Tuber Annulare and the Crura Cerebri with cineritious substance. At the upper extremity of the crus where the optic nerve crosses it, the corpus striatum, a large mass of cineri- tious substance, exists, and is mixed with the fibres of the crus, by which an immense number of new fibres is generated and added to the course of the others. These fibres, shortly after their origin, begin to di- verge, and being expanded in several directions termi- nate in the convolutions of the anterior and middle lobes of the brain; not in all of the convolutions belong- ing to these lobes, but in the inferior anterior and ex- terior. In this way the original fibres of the corpora BRAIN AND SPINAL MARROW. 89 pyramidalia may be traced through the medulla ob- longata, tuber annulare, crura cerebri, and corpora striata, to their terminations. The fibrous fasciculi on the posterior and external part of the medulla oblongata formed by the corpora olivaria, and a few others just behind, ascend in the same manner as the corpora pyramidalia through the transverse fasciculi of the pons varolii which come from the cerebellum. By meeting also with cineritious substance they are multiplied, but less considerably than the fasciculi from the corpora pyramidalia. They form the interior and posterior part of the crura cere- bri and pass through the thalami nervorum opticorum. The thalamus consists principally of cineritious sub- stance, through which the fasciculus of the corpus olivare having to pass, the fasciculus has an accession of many new fibres. M M. Gall and Spurzheim reject the opinion of the optic nerve arising from the thalamus, and rather consider the thalamus as one of the ganglions of the brain, being appropriated to the production of a great number of fine fibres, which as- cend in a diverging direction, and which at their exit from the superior margin of this ganglion form large fasciculi. The anterior fasciculi of the thalamus pe- netrate the corpus striatum where it forms a part of the lateral ventricle, and receive from it a considera- ble accession of new fibres. All the several fasciculi of the thalamus, by radiating very widely, are finally distributed in the convolutions of the posterior lobes M 90 OF THE HEAD AND NECK. of the brain, and in the superior convolutions of the anterior and the middle lobes. From the pyramidal fasciculi passing through the corpora striata and being there multiplied, and from the olivary fasciculi passing through the thalami and being also multiplied, the corpora striata and the tha- lami are said to be ganglions, or an apparatus of in- crease where many new fibres arise and join others. By such arrangement new cerebral fasciculi are added to the old in the same way that many branches might be engrafted upon the stock of a tree. commissures of the cerebrum. "The Hemispheres of the Brain offer the same phenomena as the cerebellum in regard to the two or- ders of nervous fibres. The fibrillae which come from the crura cerebri in expanding in order to form the duplicatures or convolutions at the periphery of the hemispheres, stop, as has been observed, with their points in the cineritious substance. But it is certain that besides these fibres there may be demonstrated in all the circumference of the hemispheres beyond the tissue on which rests the base of the convolutions, a particular nervous substance, which appears to be at first spread in layers, and which is afterwards united into filaments, and lastly into distinct fasciculi. The fasciculi converge or incline towards the interior of the brain in order to form with their congeners of the BRAIN AND SPINAL MARROW. 91 opposite side a commissure between the two hemis- pheres. In some convolutions of the part folded below the posterior lobe, this converging mass may be fol- lowed in an uninterrupted bed till it forms distinct filaments. For this reason it is that we presume that this white and soft substance to be met with in all the convolutions, is continued every where in the same manner to the commissures, although it be not sus- ceptible of distinct demonstration." u As these fibres converge, and as they have in eve- ry part a different course, and indeed in some places one altogether different from the diverging fibres, or such as come from the course of the brain, parti- cularly in the anterior and posterior parts of it: As, besides this, they are separated from them, and much softer and more white, we believed ourselves author- ized to consider them as a particular nervous system." The Corpus Callosum, or Great Commissure, is derived from the converging or returning fibres of the hemispheres of the cerebrum; the fibres from the opposite sides uniting at the rapha. The anterior and posterior lobes are so disposed, that their returning fibres do not cross transversely, but in a radiated man- ner; hence the great commissure is shorter than the hemispheres, occupying only their middle part. Also as these fibres areitollected very much in consequence of their converging, the anterior and posterior edges of the corpus callosum are thicker than its middle, 92 OF THE HEAD AND NECK. presenting the appearance of a fold not unlike that of the pectoralis major at the arm-pit. The Commissura Anterior is derived from the converging fibres of the front convolutions of the middle lobe. These fibres pass through the corpora striata without adhering to them, and present on both sides of the brain the form of a bow with its con- vexity forward. The Commissura Posterior is derived from the posterior convolutions of the middle lobes of the brain, and from some of those of the posterior lobes. It also consists of converging nervous fibres, which are lost in the posterior duplicature of the Commissura Magna. It forms, at its junction with its fellow, a flat band and not a round chord, and is much smaller than the anterior commissura. The Middle Commis- sure of the cerebrum is a mass of very soft and deli- cate transverse fibres, going from one thalamus to the other, in the space between the anterior and posterior commissures. These transverse fibres are almost always torn, upon separating the hemispheres. Several other parts of the cerebrum are considered as commissures by G. and S., or consisting of con- verging fibres, as the Taenia Striata, the Posterior Crura of the Fornix, and the Lj»a or under surface of the Fornix. They do not consider the obliquity of the course of the fibres of these bodies, an objec- BRAIN AND SPINAL MARROW. 93 jection to their being commissures, inasmuch as the returning filaments of the middle parts of each hemis- phere, are the only ones which have a transverse di- rection. The Septum Lucidum is also a commissure arising by a fasciculus of fibres sometimes strongly marked, from the most internal convolution, at the anterior extremity of the middle lobe, on each side. It ascends in front of the anterior commissure, above the junc- tion of the optic nerves, and is spread into a delicate membrane, forming with its fellow the septum of the lateral ventricles. Between the two laminae compos- ing it, is a cavity called the fifth ventricle of the Brain. These laminae are extended through the middle of the great commissure, and assist in forming the rapha by means of perpendicular fibres, the direction of which is diverging towards the convex or superior part of the great commissure. It is probable that all the nerves of animal life have those commissures, and at any rate they are visi- ble in many other places. For example, they exist in the transverse fibres at the bottom of the anterior fissure of the spinal marrow and the medulla oblon- gata, in the latter of which we must take care not to confound them with the decussation of the pyramids. And besides this, the longitudinal band at the bottom of the posterior fissure, extending the whole length of the spinal marrow, keeps its several nerves concate- 94 OF THE HEAD AND NECK. nated. The transverse band behind the commissure of the cerebellum in mammiferous animals, the junc- tion of the tubercula quadrigemina and the trans- verse band at the origin of the fourth pair of nerves are similar unions or commissures. It is not possible to say with propriety that these commissures are positive unions of the converging fibres, from the corresponding parts on each side; for a perpendicular cut through the middle line of the corpus callosum, of the tuber annulare, and the mid- dle of the spinal marrow, demonstrates perpendicu- lar striae accompanied with blood-vessels. Possibly the vertical laminae on each side of the middle line, may form a seam by juxtaposition; but it is more probable that the converging fibres are continued across these. Besides the commissures, there are Transverse Bands which should be attended to. Messrs. G. and S. consider them as corresponding with the trans- verse bands at the joints of straw. They say that at every point of considerable increase there is one of them, as at the lower end of the Corpus Olivare, in the middle of the Crus Cerebri, at the external margin of the optic nerve in the Crus Cerebri, be- tween the Thalamus and Corpus Striatum, at the external margin of the Corpus Sriatum. The Eminentije Mammillares are separated ,in the human subject, but adhere forming only one body BRAIN AND SPINAL MARROW. 95 in other mammalia. Each emiuentia contains three chords, two internal and one external. The external unites with the transverse band under the optic nerve in the crus cerebri. The foremost of the two internal chords unites with the anterior crus of the fornix of the same side, and the other sinking into the interior of the thalamus, unites with another transverse band. They are true ganglions. The Pineal Gland is erroneously named, as it has nothing of a glandular structure, but is composed of cineritious and medullary substance. Four nervous threads are produced in it which go to contiguous parts, two on each side; one goes along the superior internal margin of the thalamus, and ends in one of the transverse fasciculi found in the divergent fibres. The second goes backwards and downwards, and ad- heres to the commissure of the Tubercula Ctuadri- gemina. "The Pituitary Gland is a collection of cineri- tious substance, placed behind the junction of the optic nerves. It is obviously traversed by white fila- ments which arise in it, and it is prolonged into the Infundibulum/' The Tubercula Quadrigemina. The anterior ones or the nates, are evidently ganglions for the origins of the optic nerves, (see the account of these 96 OF THE HEAD AND NECK. nerves). They are flattened and somewhat cineri- tious externally, and are united to each other by a strong and broad fasciculus, considered as a commis- sure of the optic nerves. The testes are of a more conical and elevated form, the medullary matter in them is more external, and they have also a transverse band which unites them. The use of the testes is unknown, but they are supposed to give origin to the olfactory nerves, though it cannot be demon- strated. OF THE VENTRICLES AND CONVOLUTIONS OF THE BRAIN. It has been stated that the brain has two orders of medullary fibres, the one called diverging, because they have their rudiments in the medulla oblongata, and are so spread as to have their extremities termi- nating near the periphery of the brain in the cineri- tious substance forming it. The other order of fibres is called converging, because they pass from the cir- cumference of the brain to the interior parts or mid- dle line, constituting the Commissures. These con- verging fibres cross the diverging at various angles, sometimes obliquely, sometimes in a rectangular di- rection. It is uncertain whence they proceed, whe- ther they are derived from the imperceptible and curved extremity of the diverging fibres in the same way that the veins are continuations of the arteries, or whether they are a new creation in the cortical cir- BRAIN AND SPINAL MARROW. 97 cumference of the brain when they have their pri- mitive radicules in a manner corresponding with the origins of other nerves in the different ganglions. As the diverging fibres or mass is extended in every di- rection towards the circumference of the brain, and as the converging fibres come from all parts of the same circumference, and form large layers in the upper portion of the brain, as for instance the corpus cal- losum, it results that between the two orders of fibres there are vacuities; and these are called the Ventricles of the brain. The convolutions of the Brain have generally been considered by anatomists, as intended merely to in- crease its surface, in order that the blood-vessels of the pia mater might have more convenient access to it. This opinion is renounced by Messieurs Gall and Spurzheim on account of its being too mechanical, and they think, that the convolutions are the result of a more important and finished arrangement, which is as follows. Immediately after the diverging fibres decussate the converging, which they do at the external mar- gins of the ventricles, they separate from each other and are prolonged into the convolutions, forming a fibrous expansion. These fibres are not all of the same length, for some stop near the sides of the ventri- cles at the bases of the convolutions, and others are ex- tended to the surface of the brain. By such arrange- N 98 OF THE HEAD AND NECK. ment the convolutions are also of different dephths. Each convolution consists of two layers of. the di- verging fibrous or medullary matter, which are sym- metrical, are in juxtaposition, and adhere to each other by their contiguous surfaces. Besides this, as has been several times stated, each convolution has its covering of cineritious matter, about a line or a line and a half deep. The medullary fibres penetrate somewhat into the internal face of this covering, from which it is paler and more firm than the exte- rior surface. The fibrous matter being successively inserted into the sides of the cortical covering of the convolutions, its quantity of course is diminished at the summit of the convolution; hence each simple convolution is wider at its base than at its summit. Some of the convolutions however reverse this rule, for they are flattened or depressed at their summits, like a ridge or duplicature of cloth having its top pushed a little inwards. The convolutions do not all stand out in a radiated direction as regards the cen- tre of the brain, for some of them are bent either to one side or the other. Each convolution, besides being formed by the ends of the diverging fibres covered with cineritious mat- ter, has, in its structure, nervous fibres more minute and soft than the diverging ones. These are the commencements of the converging fibres, and can be seen only in the convolutions of the posterior lobes of the brain; the inference, however, is made that they BRAIN AND SPINAL MARROW. 99 exist in all the convolutions. It is these fibres which accumulate at their decussation with the diverging ones, or immediately after, into the large fasciculi which form the ventricles and the commissures. If we separate a convolution from the brain and make a perpendicular cut across it, the cut surface is plain and exhibits no mark of being divisible into two lami- nae. Yet it does consist of two laminae with their op- posite faces in contact, and agglutinated to each other by a loose cellular tissue, in all probability. This fact is proved by the effects of hydrocephalus, for here the water acting constantly with a distending force, sepa- rates the two laminae of fibrous matter from each other, and sometimes effaces the appearance of con- volution, converting it into a membrane. The pro- longations or convolutions of the cerebellum are formed after the same fashion, except that they are divided into branches and leaves and are smaller than those of the brain. In the case of a woman affected with hydrocepha- lus, Dr. Gall found the following condition of the brain. The cerebral mass was extended into a large bladder, by which the total or partial disappearance of all the convolutions had been produced. In places where they had disappeared entirely the cineritious substance was of almost uniform thickness. All the interior surface of the enlarged ventricles was per- fectly white, and, in a majority of places, not only the 100 OF THE HEAD AND NECK nervous fibres were distinctly seen, but the blood-ves sels which accompany them. The ventricles con- tained about four pints of clear and limpid water. The fibrous structure and the blood-vessels had no where been impaired. This woman died at the age of fifty-four of an inflammation of the bowels, but from her earliest infancy she had been afflicted with hydrocephalus. She was not very thin, and was as active and intelligent as Women of her class in gene- ral. This observation led to a train of reflections which terminated in Dr. Gall separating, artificially, the two laminae of the convolutions of the brain. His plan is to remove the pia mater from the whole surface of the brain, and then to introduce the fingers through the inferior part of the brain into the inferior process of the lateral ventricle along the course of the taenia striata. By this means they may be carried into the body of the lateral ventricle, and by gently extending and separating them, the convo- lutions are easily unfolded into a membrane without destroying of their fibres. During this operation a slight resistance is felt at the circumference of the ven- tricles and at the base of the convolutions at the place where the diverging and converging fibres cross each other. But the tissue which connects them being la- cerated, the remainder of the separation is effected without much difficulty. All the interior of the ce- rebral expansion, thus produced, resembles a case of hydrocephalus; the fibrous structure being unimpair- BRAIN AND SPINAL MARROW. 101 ed, white, and smooth, and covered externally by the cineritious matter. The crossing of the two orders of fibres is easily demonstrated, but they cannot be detached from each other without tearing their texture; this, however, may likewise take place in hydrocephalus, by the slow and uniform pressure of the water continually increas- ing in the ventricles. . A much easier way to demonstrate the convolution as consisting of two layers, is to remove it from the rest of the cerebral mass and to make a transverse cut through it, from its summit to its base; by a gentle pressure then with the finger and thumb from the summit to the base, the two laminae of fibrous matter may be readily separated from each other, leaving their faces, which were in contact, smooth and unin- jured. Take a section of the periphery of the hemisphere which has been detached a little distance from the circumference of the ventricles, and consequently nearer the surface than the intertexture which unites the diverging and converging fibres. If the convex part of this be laid in the palm of the hand so as to allow the weight of the section to operate in drawing the convolutions asunder, a very slight additional ef- fort will be sufficient to separate them and to show \02 OF THE HEAD AND NECK. that their laminae are only agglutinated to each other. While this process is going on a little groove or fis- sure is seen at the place of separation, as well as the perpendicular direction of the fibres and of the blood- vessels. Let sections of the brain be hardened for some time in alcohol, or in nitric or muriatic acid diluted with alcohol, or be boiled in oil for ten or twelve mi- nutes, the laminae of the convolutions may then be separated without difficulty, (and only in the middle line where they are joined together,) by pressing from their summit to their base with the finger and the thumb. The fibrous expansion will be demonstrated clearly, but there will be no vestige or appearance of lacerated fibres. The following experiment is thought by the author of this system, to prove incontestably that each con- volution consists of two fibrous layers, and that these layers do not grow together, but are lightly adherent the one to the other. By blowing with a small tube transversally on a convolution, the convolution is broken to pieces, and no distinct result follows; but by blowing with the same pipe in the direction in which the natural fissure of the convolution is sup- posed to exist, the convolution splits from top to bot- tom. By trying the same experiment on a convolu- tion somewhat depressed at its summit, it opens at the base by a simple fissure, and at the superior part BRAIN AND SPINAL MARROW. 103 this fissure is extended towards each angle by being bifurcated. By injecting water in the direction of a fissure through a finely pointed syringe, the separa- tion of the convolution is made with still greater fa- cility than with air, so that the water passes for the distance of an inch or more into the convolution, and even extends itself into the convolutions communicat- ing with this one: of which the examiner may be assured by cutting off the tops of such convolutions. This last experiment will succeed by injecting the water in a transverse direction upon a convolution; so soon as the water has washed away the lamina first opposed to it and gets to the middle, it extends itself laterally in the direction of the fissure of the convo- lution.* Under the conclusiveness of such demonstrations the authors of the system very justly complain, that instead of considering the convolutions both of the Cerebrum and Cerebellum as consisting of two lami- nae of fibrous matter placed one against the other and covered by cineritious substance, anatomists still con- tinue to talk of a substance in the convolutions, which is white, soft, and pulpy. * In all these experiments on the convolutions, it is better to ■ have the pia mater removed previously. 104 OF THE HEAD AND NECK. OF the nerves of the head. These nerves are studied in a way the reverse of the old systematic plan. The most of them can be traced very satisfactorily to the medulla oblongata, and therefore they are considered from below upwards. Gall breaks up the association forming the 8th pair, and describes each as a distinct nerve. The Accessory Nerve. It forms a natural com- munication between the nerves of the neck and those of the head, for some of its branches arise in the neck and others in the head. They all come from the posterior segments of the spinal marrow and medulla oblongata; but their origin varies in dif- ferent individuals, and in the two sides of the same in- dividual, sometimes beginning at the fifth, and some- times at the seventh cervical nerves. They arise for the most part by single threads which unite successively into a common chord, but sometimes these threads are multiplied, and then form a single chord, which joins with the main nerve. This nerve is spent upon the Sterno-Mastoid and Scapular Muscles, and upon the Pharynx. Hence the sympathy of the stomach and oesophagus with these muscles. The convulsive motions of the shoulders, oesophagus and pharynx^ in hydrophobia, and the stiff- BRAIN AND SPINAL MARROW. 105 aess of the shoulder and sterno-mastoid muscle in stomach complaints. The Hypoglossal Nerve, arises in part between the Corpus Pyramidale and Olivare, and partly below them. Its threads issue after the manner of the spi- nal nerves, separately. These threads unite and form three or four fasciculi, which join successively into a common chord. The hypoglossal nerve is distribut- ed to the tongue and to all the muscles attached to the os hyoides and to the salivary glands. It is con- nected also to nearly all the nerves found in the neck and throat by anastomosis. It does not taste, but acts in the motions of the tongue performed in mastication, deglutition, &c. Gall says its communication with the cervical nerves, explains how the voice is lost in inju- ries of the cervical medulla. The Par Vagum, or Nerve of Voice, arises by numerous filaments from the side of the medulla ob- longata between the corpus olivare and restiforme, nearer the latter. At their origin these filaments are distinct, but they afterwards unite to form a flattened cylinder, which passes out with the internal jugular vein. It is united with nearly all the nerves of the neck by anastomosis, and being distributed to the larynx, lungs and stomach, it performs an extremely interesting part in the animal economy. From this we understand how its injuries impair the voice; how nausea, cough and vomiting follow the tick- o 106 OF THE HEAD AND NECK. ling of the pharynx; the connexion between th* speech and the voice, &c.; and the oppression and cough from sordes in the stomach. The Glossopharyngeal Nerve, composed of several filaments, arises from the medulla oblongata near the tuber annulare, and just above the par va- gum. It is united by ramifications in the neck to the facial and sympathetic, and is spent upon the constric- tors of the pharynx, and the muscles of the tongue. All the nerves as yet described correspond very closely with those of the spinal marrow, inasmuch as they arise in the cineritious substance placed interi- orly in regard to the point at which they issue, and unite into one or several fasciculi. The nerves that follow have the peculiarity of being successively pro- duced by cineritious substance, and of uniting in the cerebral mass into a fasciculus which rises towards its surface, being more or less visible according to cir- cumstances. The Motor Externus. The origin of this nerve is better seen in the bullock or sheep than in the hu- man subject. In man it sometimes appears to come from the tuber or medulla oblongata, or from between the two, according to the breadth of the tuber. But arising, in fact, from the lower part of the medulla oblongata, it ascends the whole length of the pyra- mids at their side in the form of a little fasciculus, BRAIN AND SPINAL MARROW. 107 and divides commonly behind the pons into two smaller fasciculi which depart from the common mass of the medulla, one behind the other. The pons va- rolii being much larger in man than in the animals just mentioned, frequently some of its transverse fibres cover the motor externus at its point of depar- ture. In this case it appears to arise from the pons, and as its filaments do ot all come from the same place, a different origin is assigned to them. The Facial Nerve is considered to arise from the place of union between the pons, medulla oblong. and crus cerebelli, but its origin is better illustrated in the sheep than in the human subject, in the for- mer of which it departs from the medulla below the posterior edge of the pons. It ascends as a fascicu- lus in the medulla oblongata between the corpus py- ramidale and the glosso-pharyngeal nerve, to a trans- verse band at the back edge of the pons in these ani- mals. Passing below this band it pierces it at the in- ternal edge of the auditory nerve. When in the human subject, there is an appearance of this nerve arising from the pons, it is a consequence of the pons being broad enough to conceal a part of its origin. This nerve explains the motions of the face in laughing or in crying, and the pains in the head and ears during the toothach. The Auditory Nerve. On the anterior face of 108 OF THE HEAD AND NECK. the fourth ventricle, transverse white medullary striae exist, supposed to be the origin of this nerve. These striae vary in number and distinctness in different in- dividuals, being arranged sometimes in rays, occasion- ally as pencils, at other times they are parallel. Of- ten those of one side are higher than those of the other; sometimes they form little bands and then again are rounded and projecting, being, in all cases, sepa- rated from each other by a fissure in the median line, Gall says he has never seen their decussation from the opposite sides spoken of by Portal. Many of these medullary striae go to the auditory nerve, but others go in part to the anterior lobules, or thrust themselves into the middle of the cerebellum. Mammiferous animals want these medullary striae; one may, therefore, assert confidently, that many of the filaments of the auditory nerve arise in the cine- ritious substance of the fourth ventricle. This cine- ritious substance is in less quantity in man, but forms an oblong elevation called Ruban Gris by the French anatomists; in the sheep, hog, horse, beef, it is the size of a pea. This body may be considered the gan- glion of the auditory nerve, and is placed precisely where this nerve winds around the corpus restiforme,. its size being always proportionate to that of the au- ditory nerve. In animals immediately behind the pons a large BRAIN AND SPINAL MARROW. 109 transverse band is extended from one auditory nerve to the other, which passes above all the other ascend- ing nervous fasciculi with the exception of the pyra- mids. In man it is covered by the posterior part of the pons, and is considered by Gall as a commissure of the auditory nerves. The Trigeminus, or 5th Pair. Comparative ana- tomy affords the surest aid in regard to the origin of this nerve, also, according to Gall. " In fish the ganglion from which this nerve proceeds is insulated, and its nervous fibres from their beginning are sepa- rated from the common mass. In mammiferous ani- mals a large fasciculus exists at the exterior edge of the under surface of the medulla oblongata, which passes beneath the transverse band already mentioned, and projects itself between it and the pons. In the ape and in man this fasciculus is covered in part by the pons, hence the opinion prevails that it arises at the side of the pons. By removing cautiously the posterior part of the pons till the fasciculus of this nerve be reached, it will then be easy to follow its en- tire course to the lower part of the exterior edge of the corpus olivare. In this manner it will be seen very readily, that even in the interior of the pons it divides into three principal fasciculi, and that its fibres are increased by the cineritious substance in different places." 110 OF THE HEAD AND NECK. The Trochlears, 4th Pair, arises from the side of the valve of the brain, but much lower down than is generally supposed, sometimes by one fila- ment, and at others by several. Gall observes, that at the place indicated generally as its origin, it only projects from the valve, which is a very different thing from its actual origin. The Motor Oculi, 3rd Pair, issues from the in- ternal edge of the peduncles of the brain between the pons and the eminentiae- mammillares. Its origin penetrates to the third ventricle, but is separated from it by an interposed stratum of medullary matter. Many filaments compose its roots which are reinforc- ed by additions from the cineritious substance called Pons Tarini, but it has no filament from the eminen- tiae mammillares, as has been asserted. The Optic Nerve. In man, but more distinctly in mammiferous animals, this comes as a large fasciculus of fibres from the nates, winds around the exterior edge of the optic thalamus, where it is united to a con- siderable mass of cineritious substance, called Corpus Geniculatum Externum, and is by it reinforced. So far the fasciculus is attached to the optic thalamus, but afterwards is only placed upon the peduncle of the cerebrum to which it adheres, by its anterior edge being united to the neighbouring cerebral fibres In front of this, the nerve becomes rounder and adheres BRAIN AND SPINAL MARROW. HI to a firm bed of cineritious substance, (tuber cinere- um,) and receives from it, particularly above, several nervous filaments which unite to each of its sides. The optic nerve is so much reinforced by these fila- ments that the increase of its bulk is very percepti- ble, particularly after its junction with its fellow. In birds the optic nerve comes very distinctly from the nates, which establishes more fully that it must have the same origin in man and in the mammalia. In the left hemisphere of the brain of a deranged fe- male, Dr. Gall found the thalamus almost destroyed by an ulcer, the corpus striatum and the hemisphere much diminished, but the optic nerve of the same side remained entire and like its fellow. The nates were in a natural state. When, on the contrary, he has found the optic nerve dwindled away, it has been at- tended with a corresponding diminution of the natis which belongs to it. In the horse, bullock, deer, &c. the optic thalami are smaller than in man, while the optic nerves themselves are larger; no proportion therefore exists between them, while it does exist as regards the nates. Messieurs Gall and Spurzheim believe that the optic nerves decussate each other, and they quote the experience of Dr. Soemmering, who had observed the fact in seven one-eyed men; and in the horse, the dog, the hog, the cat, the goat, the rat, and the rabbit. The Olfactory Nerve issues from the cineritious 112 OF THE HEAD AND NECK. substance, in the inferior surface of the hemispheres. Its first filaments are seen at the anterior part of the internal convolutions of the middle lobes; they are soft and delicate, and are surrounded for some dis- tance by cineritious substance. These filaments ap- proach each other and form commonly three princi- pal roots, the internal of which is shorter and broader than the two external. The most exterior, which is the longest, may be followed to the bottom of the fis- sura sylvii. These are the only nerves of which there is any doubt whether they take their origin in the hemispheres or not, but even if they do, they are not continuations of the medullary fibres of the hemis- pheres. Section III. of the eye. The hairs on the superior edge of the orbit are called Supercilia, and on the edges of the eyelids the Cilia. The Orbicularis Palpebrarum muscle being remo- ved, immediately beneath it are the two Tarsi Carti- lages, which form the margins and a considerable part of the breadth of the upper and of the lower eyelids. The upper cartilage is of a semi-oval figure, the broad- THE EYE. H3 est part being not quite half an inch; the lower carti- lage is of an uniform breadth, not exceeding in any part one-fourth of an inch. Their external extre- mities are united with each other arid kept in their places by a ligamentous expansion connecting them with the orbitar margin of the malar bone, and inter- nally they are fixed to the nasal process of the supe- rior maxillary bone by the tendon which affords origin in part to the orbicularis palpebrarum. The edges of these bodies are slanting so that a groove is formed posteriorly where they are in contact, by which the tears are conducted to the inner corner of the eye. Near the internal extremity of each, but not in the cartilage itself, is to be found in the centre of a small eminence a foramen (the Punctum Lachrymale) ca- pable of receiving a bristle, which is the orifice of a canal (the Ductus Lachrymalis) conveying the tears into the Sacculus Lachrymalis. On the posterior surface of the tarsi cartilages, are placed a number of white tortuous canals in contact with each other, and having their extremities on the edges of the eyelids; they are called the glands of Meibomius, and secrete an unctuous substance. In the upper lid are about thirty, and in the lower about twenty. At the internal junction of the eyelids is placed the caruncula lachrymalis, a small granulated body inferior in size to a grain of wheat. The ball of the eye is connected to the lids by a delicate, vas- cular, and highly sensible membrane, the Tunica p 114 OF THE HEAD AND NECK. Conjunctiva, which is spread over its anterior third, not excepting the cornea, but there it becomes per- fectly transparent. At the inner corner of the eye, the conjunctiva is thrown into a fold corresponding with the membrana nictitans of some animals. The Lachrymal Ducts are under the skin of the internal canthus, are three-eighths of an inch long, aiMi terminate by separate foramina in the sacculus lachrymalis. This sacculus lachrymalis occupies all of the concavity in the os unguis, and extends from a short distance above the tendon of the orbicularis muscle to the cavity of the nose, under the anterior part of the inferior spongy bone; it is contracted to the size of a small crow-qu 11 at its nasal orifice, and the e ssume the name of Ductus ad Nasum. In the superior and external part of the orbit, near its margin, is placed the Lachrymal Gland for the se- cretion of tears; it is about five-eighths of an inch long and half an inch wide, being flattened so as to suit the parts with which it is in contact. It is placed on the outer side of the tunica conjunctiva, and sends five or six small ducts through it, whose orifices are in the tunica conjunctiva of the upper eyelid near the external junction of the tarsi cartilages. The muscles in the orbit are as follow; 1. Levator Palpebr^ Superiors, arises near the superior margin of the optic foramen, and is in- THE EYE. 115 serted into the upper margin of the superior cartilage of the eyelid. Use, to draw the lid upwards. 2. Levator Oculi, arises from the superior mar- gin of the optic foramen, and inserted into the upper part of the ball of the eye near the cornea, by a flat tendon. It turns the cornea upwards. 3. Depressor Oculi, arises from the inferior mar- gin of the optic foramen, and is inserted into the lower part of the ball of the eye near the cornea. It draws the cornea downwards. 4. Adductor Oculi, arises from the internal mar- gin of the optic foramen, and is inserted into the in- ternal part of the ball of the eye near the cornea. It draws the cornea inwards. 5. Abductor Oculi, arises from the external mar- gin of the optic foramen, and is inserted into the ex- ternal part of the ball of the eye. It turns the cor- nea outwards. 6. Obliquus Superior, arises from the internal margin of the optic foramen, runs along in contact with the orbitar plate of the os frontis, passes through the trochlea near its internal angular process, and, being inclosed in a sheath sent off from the trochlea, its round tendon is inserted about half-way between 116 OF THE HEAD AND NECK. the cornea and optic nerve in the superior and inter- nal part of the eye. It turns the cornea outwards and downwards. 7. Obliquus Inferior, arises from the orbitar plate of the superior maxillary bone near the os un- guis, and is inserted into the outer part of the eyeball half-way between the cornea and optic nerve. It turns the eye inwards and downwards. At the internal canthus of the orbit is a small mus- cle belonging to the internal commissure of the eye- lids which has not been observed before, or is omitted in the descriptions of the part. That it does not be- long to either of the above, or to the Orbicularis Pal- pebrarum, a reference to very minute accounts of them given by the most eminent anatomists will prove. This muscle is about three lines broad and six lines long; it arises from the posterior flat surface of the os unguis near its junction with the os aethmoides, and passes forwards and outwards, lying on the posterior face of the lachrymal ducts. As it approaches the commissure of the lids, it splits into two parts nearly equal, each of which is appropriated to a duct, and inserted along its course almost to the punctum la- chrymale. To get a distinct view of it, the eyelids must be se- parated from the eye and turned over the nose, leav- ing the tendinous attachment of the orbicularis and THE EYE. 117 ciliaris muscles. The valvula semilunaris is brought into sight by this process, which must be dissected away, and also the fat and cellular membrane under- neath it. The muscle is now seen, and by passing bristles through the lachrymal ducts its connection with them is rendered evident, at the same time that we get a good idea of its size, origin, and insertion. While making this inspection, by turning the muscle somewhat aside, we shall be rendered sensible of an- other fact of some importance, that the attachment of the inner commissure of the eyelids to the inter- nal canthus of the orbit is imperfectly described, even by anatomists of much minuteness in their accounts. It is attributed exclusively to the tendon of the orbicu- laris muscle, so much so that in the operation for fis- tula lachrymalis we are strictly enjoined not to cut through the tendon lest a puckering of the eyelids be produced by their line of extension being destroyed. The fact, on the contrary, is, that a ligamentous matter behind this tendon passes between the internal ends of the eyelids and the posterior flat surface of the os unguis, so that admitting the tendon of the orbicu- laris to be cut through, this ligament, assisted by the little muscle described, would prevent the dreaded deformity. The internal extremity of this posterior ligament is at least half an inch from the insertion of the orbicularis tendon into the nasal process, and it brings the eyelids into the curve commonly seen at their junction. The lachrymal ducts are involved 118 OF THE HEAD AND NECK. in this posterior ligament, passing along it into the sac instead of going along the edges of the commis- sure, as commonly described, just under the skin. The muscle attempted to be described must influence considerably the position of the puncta lachrymalia by drawing them towards the ball of the eye and keeping them in close contact with it; it is, therefore, a very efficient means for regulating so far the lachry- mal passages and for securing the course of the tears. I ani indebted to Dr. Physick for a further sugges- tion in regard to its other uses, which appears highly probable. In cases of extreme emaciation it is well known that the adipose matter around the ball of the eye is more or less absorbed, causing the eye to sink deeper into the orbit, and consequently to retire some- what from the lids. The effect of the muscle is to draw the lids backwards and to keep them ap lied on the ball. Again, in the elevation of the upper lid, or rather the drawing of it within the orbit by the le- vator palpebrae, the tendency of the margin of the lid is to leave the ball; the upper part of the little mus- cle obviates this tendency. As such appears to be the actions of the part, I must, therefore, coincide with him in calling it Tensor Tarsi, a name expressive of its functions. I am acquainted with a lady who possesses, in a striking degree, the use of this muscle, its action in her being increased much beyond what is commonly observed. It is demonstrated by an ability to draw THE EYE. 119 both the eyelids of one eye towards the nose, at the same time shortening so much the space between the puncta lachrymalia and the junction of the eyelids* that the puncta are buried in the corner of the eye and carried out of sight. It would be interesting to know what is its healthy influence on the condition of the sacculus lachrymalis and lachrymal ducts in forwarding the tears from the eye to the nose, and whether we are right in attri- buting this circumstance entirely to the capillary at- traction of the puncta and to the pressure of the or- bicularis muscle. It is somewhat surprising that the idea of an appa- ratus, more perfect than what is commonly described for regulating the position of the puncta lachryma- lia, had not occurred before, and that anatomists in the dissection of the part had not observed it. The latter, I think, has arisen from the manner in which the dissection for the muscles of the eyelids is gene- rally performed; removing the skin and exposing the orbicularis and ciliaris muscles, we think the dissec- tion completely made, whereas a most interesting part of the structure is unattended to. Also in working for the lachrymal ducts and sac this muscle is indis- criminately cut away with the orbicularis. While investigating this subject my attention was called to a fact by Dr. Harlan, the observation of which is original with him. The puncta lachrymalia have a power of projecting themselves beyond the 120 OF THE HEAD AND NECK. plane of the eyelid in which they lie, and have an equally obvious power of retracting themselves so as r to do away all appearance of prominence. I do riot understand the cause of the first motion, but the se- cond depends upon the muscle just described.* The ball of the eye is composed of several coats and humours. As the human subject can seldom be obtained sufficiently fresh for a proper display of its structure, it is recommended to use the eyes of sheep, bullocks, or pigs, which can be got at any time The eye is to be removed from the orbit and cleared of its fat, muscles, and so on. Anatomists have devised va- rious means for fixing it for dissection, and any of them will answer sufficiently well; for my own part I have never found any thing necessary besides a com- mon saucer, and water enough in it to float the or- gan; the specific gravity of this fluid approaches so nearly to that of the eye, that it affords a very good support to its delicate membranes, and sufficient sta- bility for most purposes of examination. The first coat of the eye, called Tunica Sclerotica, is to be examined by opening the ball very freely and turning all of its contents out. We shall then see that it has considerable thickness, being of a compact fibrous texture, possessed of little elasticity, and there- * The foregoing account of the Tensor Tarsi muscle was communicated to the American Philosophical Society in March 1822. " See Transactions for the present year. THE EYE. \2\ fore well calculated for giving support to the interior structure. It is white and tendinous like the dura mater, and has few vessels or nerves. It is connect- ed behind to the optic nerve, where it is perforated by several small holes for the passage of the nerve, and before to the Cornea. The cornea is a perfectly transparent membrane, consisting of many lamina? united by a delicate cellular substance. It is much more convex than the sclerotica, and is united to it by a broad sloping edge, where the two membranes ad- here very firmly to each other, by the sclerotica over- lapping the cornea. They may be separated by pu- trefaction. The cornea in a healthy state has no red blood circulating through it. It is covered before by the tunica conjunctiva, which there becomes assi- milated in its sensible properties to it, and behind by the capsule of the aqueous humour. An eye being floated in the manner just mention- ed, a puncture is to be made with a lancet or sharp- pointed scalpel, through the sclerotica about half way from its centre; and the blunted blade of a pair of scissors being introduced through the opening, a cir- cular cut should be made all around, taking great care not to injure the coat below. By making radiated sections from this circular to the optic nerve we shall be able to peel off, with but little difficulty, all the posterior part of the sclerotica, taking care however to leave the optic nerve. What remains of the anterior Q [22 OF THE HEAD AND NECK part of the sclerotica may be easily drawn away along with the cornea. This stage of the dissection gives a good view of the Tunica Choroides, lining all the interior surface of the sclerotica; of a white circle, seeming to terminate it before, called the Ciliary Ligament; and of the Iris placed upon the fore part of the eye, an opening in the middle of which affords a glimpse of the internal structure. The tunica choroides is a much thinner and more delicate membrane than the sclerotica; it appears black, and is covered on the outside with a flocculent cellular substance connecting it with the sclerotica. Its black colour depends upon a large quantity of colouring matter deposited principally on its inner surface, and called pigmentum nigrum. The tunica choroides abounds with blood-vessels, which make it look perfectly red in living animals devoid of the black pigment. It has a singular arrangement of veins, which can be made distinct only by injection. They are called Vasa-Vorticosa. It is well furnish- ed with nerves, which appear like flattened pieces of white thread lying on its outside. If the Iris be torn away, the anterior edge of the membrane is seen ter- minating in a fringe called Corpus Ciliare, and this fringe, if closely observed, will be seen to consist of a great number of short and distinct processes, cover- ed with pigmentum nigrum. The Iris is a membrane placed across the eye just behind the cornea; it is highly vascular, but having a THE EYE. Igg large quantity of pigmentum nigrum on its posterior surface, the vessels are not evident in a living state. Its anterior surface determines the colour of the eye. In its centre is a round hole, called the Pupil, for ad- mitting light, which is increased or diminished by the action of circular and radiated fibres composing the body of the membrane. In the foetus the pupil is closed by the Membrana Pupillaris till the seventh month. The Ciliary Ligament is a circle of whitish sub- stance, consisting of short fibres, which is placed around the anterior part of the eye, and serves to connect strongly the Iris with the Tunica Choroides; and these again with the anterior edge of the Sclero- tica and the margin of the cornea. In it is a canal called the Aqueduct of Fontana. Having finished the examination of these parts, with two pair of fine forceps strip off the whole of the Tunica Choroides. This is one of the most delieate manipulations in the whole dissection, and must there- fore be done with the greatest care. If it be well done, the most delicate membrane in the human frame will be found lining the choroid coat; it was lately discovered in Dublin, by Mr. Jacobs, and may be sa- tisfactorily demonstrated, by commencing at the optic nerve with the extremity of a knife-handle, and turn- ing it down by scraping towards the anterior part of 124, OF THE HEAD AND NECK. the eye. It extends from the optic nerve to the an- terior edge of the Retina. Beneath the Tunica Jacobi, is placed the Retina, a delicate, transparent, and pulpy membrane, extend- ing from the optic nerve distinctly to the commence- ment of the Ciliary Processes; and some anatomists maintain that it goes on as far as the circumference of the Crystalline Humour, which is by no means so obvious. The optic nerve, after penetrating the cri- briform part of the Tunica Sclerotica, forms a bulb on its inside; from this bulb the membrane called Retina, is expanded over the interior surface of the eye. The Retina consists of two layers; the internal is a very delicate and a vascular net-work, consisting of fine meshes; the external is the proper nervous matter, having a consistence not much stronger than common mucus. In the centre of the optic nerve is seen the artery which supplies the Retina, called the Arteria Centralis; the branches of veins correspond with the arterial ramifications, and it is the latter which we commonly see distended with blood in our dissections. In the centre of the Retina is the fora- men of Soemmering, found only in man and the mon- key, surrounded by a yellow spot, and having a fold connecting it to the bulb of the optic nerve. Impres- sions made on the Retina are supposed, generally, to be the cause of vision, and of the contractions and dilatations of the pupil. Dr. Physick believes, in regard to the latter, that the Iris is immediately sti- THE EYE. 125 mulated by the light, as he has seen cases where the motions of it were active, and well marked in paraly- sis of the Retina. The Humours of the Eye are three, the Vitreous. Crystalline, and Aqueous. They are all perfectly transparent, but differ much in their consistence and structure. The Vitreous occupies nearly all the eye posterior to the Iris; it is like melted glass, from whence its name. When minutely examined, it is found to consist of a fluid like water contained in a very delicate membrane or capsule, which is cellular: the peculiar consistence of it is therefore derived from the latter. This capsule, called Tunica Hyaloidea, is fixed at the bottom of the eye by a branch of the central artery of the Retina, and before, by a close adhesion to the Ciliary Body. The Retina lies loose upon it. The Crystalline Humour is fixed on the anterior part of the Vitreous just behind the pupil. It is a double convex lens, about five lines in diameter, the posterior convexity of which is much the greatest. Its consistence is that of half dissolved gum arabic, but becoming more solid towards its centre. By putting it in boiling water for half an hour, it becomes hard and opake, and enables one to unravel its structure. It consists entirely of concentric lamellas, which, with a needle, may be separated into very fine fibres. It is enclosed in a capsule of the same shape, and be- tween it and the capsule is found a small quantity of 126 OF THE HEAD AND NECK. transparent fluid called Liquor Morgagni. Anato- mists do not agree in regard to the origin of the cap- sule, some thinking that it is entirely derived from the tunica hyaloidea, others that it is totally distinct from it. The Professor of Anatomy in this Univer- sity, is decidedly in favour of the first opinion. To common inspection on the sheep's eye, the tunica hy- aloidea approaches the circumference of the lens, and then splits mto two laminae, one going before and the other behind it, to form the capsule. If this be the fact, the structure of the tunica hyaloidea is unques- tionably much altered, especially in front, as the cap- sule is possessed of more thickness, is elastic, and cuts very much like the thin shavings of a finger nail. In die tunica hyaloidea surrounding the circumference of the capsule of the lens, is placed the Canal of Pe- tit, which, when inflated or injected, is seen to be di- vided in a radiated manner by a number of incom- plete partitions. The Aqueous Humour is placed between the lens and the cornea, and is nearly as thin as water. The Iris floats in it, which has occasioned the division of the space occupied by the aqueous humour into An- terior and Posterior Chambers of the Eye; all the space of the aqueous humour behind the Iris being called the Posterior Chamber, and all the space before the Iris being called Anterior Chamber. Both of these chambers are said to be lined by the capsule of the aqueous humour; this membrane, however, is not THE EYE. 121 very evident except on the posterior surface of the Cornea.* The ball of the eye and the muscles surrounding it, are imbedded in a considerable quantity of adipose matter, the profusion of which, in health, gives pro- minence to the organ; and the absorption of which, in disease, produces the sunken eye. of the vessels and nerves met with in the orbit. To display these parts, the roof of the orbit must be entirely removed. The Internal Carotid Artery, as it lies near the anterior clinoid process of the Sphe- noid Bone, detaches a large branch; the Ophthalmic, which is first under the optic nerve, then gets to the outside of it, and finally winds over to the inside of fhe nerve passing through the optic foramen. Near the posterior part of the eye it sends off a branch which penetrates to the centre of the optic nerve, and is distributed to the retina. It afterwards divides into several branches which go to the Lachrymal gland,—to the muscles of the Eyeball,—to the Tuni- ca Choroides, constituting the Long, Short, and An- terior Ciliary Arteries ;—and finally, branches which pass through the anterior and posterior asthmoidal foramina and through the superciliary foramen. At the bottom of the orbit, and coming out at the infra- * See Journal Universelle. A paper by Mr. J. Cloquet. 128 OF THE HEAD AND NECK orbitar foramen upon the face, is found a large branch of the Internal Maxillary. The veins of the orbit have very much the same course with the arteries, some being connected with the facial vein at the internal angle of the eye, and passing into the external jugular; and others, sending a trunk through the foramen opticum, which runs into the cavernous sinus, and consequently into the la- teral sinuses. Five trunks of Nerves are to be found in the Orbit 1st. The Optic, which is expanded into the Re- tina. 2d. The Third Pair, or Motor Oculi, which pass- ing through the foramen lacerum into the orbit, di- vides into two branches. One goes to the upper part of the orbit, and is distributed to the Levator Oculi and the Levator Palpebrae Superioris; the other goes to the Adductor, the Depressor, and the Obliquus In- ferior, From the second branch is sent a filament which runs to the Lenticular or Ophthalmic ganglion, situated on the outside of the optic nerve near its entrance into the orbit. 3. The Trochlears, or Fourth pair of nerves, is exclusively appropriated to the Obliquus Superior muscle, and also gets into the orbit through the Su- perior foramen lacerum THE EAR. 129 4. The Motor Externus, or Sixth nerve, passes through the superior foramen lacerum of the orbit, and is spent on the Musculus Abduetor. 5. The first branch of the Fifth nerve, or the Oph- thalmic, passing also through the foramen lacerum, divides into the Frontal, Nasal, and Lachrymal. The first has but little to do with the Orbit, as it simply passes along its superior part to get out upon the fore- head, through the supra-orbitar foramen and Trochlea of the os frontis. The second passes along the inner side of the orbit, sends a filament to the Lenticular ganglion: another through the anterior aethmoidal foramen which goes ultimately to the nose, and what remains is distributed to the lachrymal sac and the contiguous parts. The third branch goes to the La- chrymal Gland, whence its name. Section IV. OF THE EAR. The organ of hearing may, for the purpose of study, be divided into three parts, the boundaries of which, even by nature, are well defined; to wit, the External Ear, the Tympanum, and the Labyrinth. R 130 OF THE HEAD AND NECK. 1. The External Ear consists of the structure exterior to Hie head, and of the passage leading to the interior of the petrous portion of the temporal bone, called Meatus Auditorius Externus. The part, in common language called Ear, is prin- cipally cartilaginous, but to the lower edge of the car- tilage is appended a softer structure consisting of de- licate granulated adeps, with a kind of tendinous cel- lular membrane. The cartilaginous portion is called Pinna, the other Lobus. The pinna presents a very unequal surface both on the outside and on the in- side. The former being the part employed in collect- ing rays of sound and converging them through the meatus externus, merits our principal attention. The deep concavity in the middle of it is called Concha. In the upper part of the concha, and dividing it into two unequal fossae, we find a ridge of cartilage com- mencing, which is traced in the form of a scroll along the circumference of the pinna till it terminates in- sensibly in the posterior part of the lobus. This fold is called Helix; within it is a ridge of cartilage ter- minating above by a bifurcation, which is the Anti- helix. On the anterior part of the concha, and over- lapping it obliquely, is the cartilaginous process called Tragus, and opposite to it at the lower end of the an- tihelix is the Antitragus. Under the fold of the helix is the Cavitas Innominata, and between the bifurca- tion of the antihelix is the Scapha. THE EAR. 131 The Meatus Auditorius Externus is about one inch in depth, calculating from the bottom of the concha; it proceeds obliquely forwards in a course corre- sponding to the situation of the petrous bone, and be- sides that has a curve with the convexity upwards. The internal half is bony, but the outer half is com- posed of cartilage and of ligamentous matter. If the skin be removed from the ear it will be seen that the concha is formed not entirely by cartilage, but at the bottom of it, and connecting it and the commence- ment of the helix with the tragus, is a ligamentous expansion which contributes also to the meatus ex- ternus. In the antitragus cartilage, near the bone, are found two fissures filled up with elastic ligamen- tous substance; they are called Incisurae. The whole of this arrangement of cartilaginous and membranous matter is highly favourable to the exercise of the sense, as the former, by its resistance, is well calcu- lated for reverberating sound, and the latter affords great facility of motion as a kind .of hinge is formed by the several incisurae. The cartilaginous is joined to the bony meatus by the exterior edge of the pe- trous bone being rough and irregular for this pur- pose; there are also three ligaments, one sent to the mastoid process, one to the zygomatic process, and a third to the temporal aponeurosis. The external ear is covered by a delicate skin hav- ing a great number of sebaceous follicles in it; as the skin descends into the meatus it becomes still more 132 OF THE HEAD AND NECK. delicate and sensible, is beset with hairs, and under it are found, in considerable numbers, the glandulae ce- ruminosse which secrete the wax. On the external ear are five muscles, which can sel- dom be seen distinctly enough to merit the name. On the superior and anterior part of the helix is the Helicis Major; on its inferior part is the Helicis Mi- nor; on the posterior side of the tragus is the Tragi- cus; on the anterior part of the antitragus is the An- titragicus; and on the outside of the ear is the Trans- versa Auris. In most persons there are three muscles appropri- ated to the movement of the external ear on the head, which, though sufficiently well developed, are scarcely ever employed. The Attollens Auris, which arises by a broad membrane from the tendon of the occipito frontalis and the fascia of the temporal muscle, and is inserted into the prominence made by the Scapha or Fossa Naviculars. The Anterior Auris, which arises from the temporal fascia just above the posterior part of the zygoma, and is inserted into the anterior part of the helix. And the Retrahentes Auris, consisting of two slips, the inferior of which arises from the ante- rior edge of the root of the mastoid process, and is inserted into the prominence made by the concha below; and the second slip arises from the temporal bone higher up than the former, inserted also into the back of the concha above the first. The names of these muscles express their action. THE EAR. 133 2. The Tympanum is situated in the outer part of the Petrous Bone, and separated from the Meatus Externus by a partition called Membrana Tympani. The membrana tympani is placed just at the bottom of the meatus, very obliquely, the upper part being the outermost. It is not flat, but has its centre drawn inwards by the handle of the malleus. It consists of four layers, the cuticle, the true skin, the proper membrane, and the lining membrane of the tympa- num. When successfully injected, it shows a high degree of vascularity. The two outer layers are easily separated from the others, and do not partake much of their vascularity. The tympanum contains a great deal of curious and interesting structure; its depth is about three lines; its antero-posterior diameter, six lines; and its verti- cal diameter rather more. On its superior posterior part is an oval opening communicating with an exten- sive cellular arrangement in the Mastoid Portion of the temporal bone; and on its anterior side is seen the canal of Eustachius going to the Posterior Nares. In the bottom and central part of the tympanum, is a striking convexity, the Promontory, just above the superior edge of which is the Foramen Ovale, and be- low and somewhat behind it, is the Foramen Rotun- dum. On the posterior surface of the tympanum, in a line with the foramen ovale, is a very small bony process, the Pyramid, which is hollow, and has a hole m its apex. 134 OF THE HEAD AND NECK. Four small bones are found in the tympanum, which form a chain between the membrana tympani and the Labyrinth; they are the Malleus, Incus, Os Orbi- culare, and Stapes. The Malleus is placed before the others, and con- sists of a spherical head, a neck just below the head, uniting it with a tapering handle; a long and crooked projection on the anterior part of the neck, called Processus Gracilis, and a short one on the outside below the other, called Processus Brevis, which sends out a round ligament to the edge of the tympanum. The Incus resembles somewhat a molar tooth, with two fangs widely separated, and one much longer than the other. The superior and anterior part of the body of the bone is excavated for articulating with the head of the Incus. From the lower part of the body proceeds the Processus Longus; and from the back part looking into the orifice of the mastoid cells is the Processus Brevis. The Os Orbiculare is a flattened sphere about the size of a mustard-seed, placed between the extre- mity of the long process of the Incus and the Stapes The Stapes resembles very much a stirrup-iron, and is placed horizontally at right angles with the malleus. It has a small head articulating with the os orbiculare THE EAR. 135 from which proceed an anterior and a posterior crus. On the inner side of each crus is a fossa running its whole length. The crura diverging in their progress and gently bent, are united by a broad base, which corresponds in its dimensions with the foramen ovale over which it is placed. To get a good view of the malleus and incus, we must cut away the superior margin of the tympa- num, their bodies will then be seen placed vertically and in contact, a complete articulation being formed by them. The cavity of the tympanum is lined by a delicate and vascular membrane, continued through the Eu- stachian tube from the pharynx, and into the Mastoid Cells. The little bones are all covered by a reflec- tion of the same, and the foramen rotundum is closed up by it. There are three muscles appropriated to the move- ment of these bones, two to the Malleus, and the other to the Stapes. The Laxator Tympani, placed in the glenoid fis- sure of the temporal, and arising from the spinous process of the sphenoid bone, is inserted into the pro- cessus gracilis of the Malleus. It draws the Malleus outwards, and consequently relaxes the membrane of the tympanum. The Tensor Tympani arises from the cartilage of 136 OF THE HEAD AND NECK. the Eustachian tube, lies in its upper bony part, and is inserted by a tendon into the neck of the malleus, a little below the processus gracilis. It draws the handle of the malleus inwards. The Stapedius occupies the conical cavity of the pyramidal process, and is inserted by a delicate round tendon into the head of the Stapes. It draws this bone backwards, and detaches it somewhat from the foramen ovale. 3. The Labyrinth. To obtain a good view of this structure, a foetal bone must be procured, as the laby- rinth is more accessible in it and nearly as fully de- veloped as in the adult. The petrous bone here has a condensed, but thin structure on its surface, which being removed, brings into view a soft and cellular bone easily managed with a pen-knife. By paring it away, we come in contact with the labyrinth, which is readily recognized by its hardness and brittleness, and may be got out with but little trouble. Having pro- ceeded thus far, the labyrinth is seen to consist of three parts; above and posteriorly are the Semicircular Canals, in the centre is the Vestibule, and below is the Cochlea. The whole of this structure is hol- low. The Semicircular Canals attached to the back and upper part of the vestibule, are so situated that one THE EAR. 137 is Superior, another Posterior, and the third Exte- rior. The superior and posterior are united together at their upper extremities, and therefore have a com- mon canal entering into the vestibule; their other extremities are widely divergent from each other, and enlarged, each forming an ampulla before it enters into the vestibule. The exterior canal is shorter than the others, lies nearly horizontal, and has its exterior extremity enlarged also into an ampulla which is placed near the ampulla of the superior canal. These three canals, from two of them uniting, have only five orifices in the vestibule. The vestibule has a cavity about the size of a grain of barley, and is placed just on the inner part of the bottom of the tympanum. The foramen ovale is the common orifice between them. On the superior and exterior part of the cavity contiguous to the openings of the canals is the semi-elliptical depres- sion, and below this and somewhat more internally is the hemispherical depression, the recollection of both of which will be useful to us at a subsequent period of the description. At the lower part of the vesti- bule is a foramen communicating with the cavity of the cochlea. The Cochlea, consisting of a conical tube wound spirally two and a half times on itself, is fixed at the anterior part of the vestibule. It has a broad cribri- form base forming the bottom of the meatus audito- rius internus, and an apex which occasions the pro- s 138 OF THE HEAD AND NECK montory in the tympanum. Passing from its base towards the apex is a pillar of bone called Modiolus, on which the conical tube is wound. This pillar ta- pers almost to a point, and then is spread out into a cavity resembling a funnel, from whence the name of Infundibulum. The apex of the cochlea from its covering over the Infundibulum is called the Cupola. When the conical tube is cut open freely a parti- tion is seen to divide it into two equal portions from the base to the summit. This partition, called Lamina Spiralis, arises by two delicate lamellae of bone with an intermediate cellular structure from the Modiolus, but does not go completely across the canal, for on minute examination the lamina spiralis is seen to con- sist besides of cartilage, of a cellular portion contain- ing a fluid, and of a membrane. These portions are called zones, we therefore have Zona Ossea, Coria- cea, Vesicularis, and Membranacea. The lamina spi- ralis terminates in the infundibulum by a process call- ed Hamulus. The divisions in the Cochlea thus made by the lamina spinalis form the scalae. The lowest of these scalae has the foramen rotundum looking into its base, and the upper communicates by the foramen at the bottom of the vestibule with the cavity of the vesti- bule. From these communications we have the names Scala Tympani, and Scala Vestibuli. The scalse communicate also with each other just at the hamulus in the infundibulum, THE EAR. 139 The whole labyrinth is lined by a highly vascular membrane, exhibited by our preparations in the uni- versity, which seems to be very different from com- mon periosteum. Thus far the description has applied only to the bony labyrinth, but by removing it we shall find besides the vascular membrane just mentioned, the following parts: Membranous semicircular canals within the bony, conforming to their figure and con- taining a pellucid fluid. These canals all communi- cate by their extremities with a sac, situated in the semi-elliptical depression of the vestibule, called Al- veus Communis. Within the vestibule, and occupy- ing the hemispherical cavity, is anottier sac smaller and distinct from the former, like a bubble filled with a transparent fluid; it is the Sacculus Sphericus. To complete this part of the description of the labyrinth, it is to be observed that between the bony and mem- branous canals, in the vestibulum on the outside of the sacs, and in the scalae of the cochlea, is to be found a transparent fluid, which can pass from one of these cavities into the other by the foramina already mentioned. It is in connection with this fluid that we find two aqueducts for its removal, one for the Vestibule, an- other for the Cochlea called after Cotunnius. The first arises near the common orifice of the superior and posterior semicircular canals, and discharges it- self just behind the meatus auditorius internus. The 140 OF THE HEAD AND NECK. other comes from the cochlea near the foramen ro- tundum, and runs into the jugular fossa just at the root of the spine for separating the eighth pair of nerves from the internal jugular vein. The Nerve of Hearing, or the Portio Mollis, is distributed throughout the labyrinth. The bottom of the meatus internus being divided into two unequal parts by a ridge; the uppermost is the smaller and per- forated with several foramina, all of which, except the anterior large one, are appropriated to the pas- sage of the portio mollis to the vestibule. The larger fossa at the bottom of the meatus is also cribriform, and forms the basis of the cochlea; through it pass fibrillae to the cochlea, vestibule, and semicircular canals. The portio mollis, descending to the bottom of the meatus, passes then, in several divisions, to the soft structure within the bony labyrinth. One divi- sion, entering the vestibule, is spent on the alveus communis and membranous canals; another division goes to the sacculus sphericus. A third division, pe- netrating from the base of the modiolus, runs through it and comes out upon the lining membrane of the cochlea, between the plates of the lamina spiralis and through the infundibulum and other parts. The fibrillar of the portio mollis, during this distribution, continue exceedingly delicate, and are finally found in a pulpy state resembling the retina upon the inter- nal surface of the cavities and sacs just mentioned. THE EAR. 141 The Portio Dura, though not concerned in the function of hearing, passes through the petrous bone in a curious manner. Entering into the large fora- men in the upper fossa of the meatus internus, it goes forward almost as far as the vidian foramen and there makes a very abrupt turn backwards, forming an acute angle called its elbow. It then runs just above the foramen ovale making a ridge in the tympanum, con- tinues its course so as to surround the back part of the tympanum, and emerges at the foramen stylo-mas- toideum. It is afterwards distributed to the face. Its canal in the bone is called the aqueduct of Fallo- pius. The Chorda Tympani, a branch of the pterygoid nerve, passes into the vidian foramen and joins the portio dura, running closely connected with it almost to the stylo-mastoid hole. It then leaves the portio dura at an acute angle and enters into the back part of the tympanum, crosses this cavity completely, going between the long leg of the incus and the handle of the malleus. It gets from the tympanum through a foramen in the fissure of the glenoid cavity, and joins ultimately the lingual branch of the fifth pair of nerves, it sends fibres to the membrana tympani and to the muscles of the malleus. The labyrinth is principally supplied with blood from a branch of the vertebral artery which gets to it through the meatus internus. The tympanum and 142 OF THE HEAD AND NECK. external ear are supplied from the stylo-mastoid and temporal arteries. Section V. OF THE NOSE. In order to understand this part of our structure it is necessary to be well acquainted with the bones constituting its cavity, both individually and collec- tively. Being thus prepared, we shall see that the nostrils which are incompletely separated from each other in the skeleton have a perfect septum in the recent dissection, which renders them two distinct ca- vities. This is effected by a cartilage placed at the anterior parts of the vomer and of the nasal lamella of the aethmoid bone. At the junction of this carti- lage with the nasal suture it spreads out on each side into a wing, and is attached to the lower edge of the nasal bones, extending, by such means, the bridge of the nose. Proceeding from the lower edge of the wing of this cartilage, and from the external bony margin of the anterior naris, is an elastic ligamentous mem- brane forming the side of the nostril. At the ante- rior part of this membrane is an oval cartilage which forms two-thirds of a ring, the exterior portion of it THE NOSE. 143 is the broadest; the internal portion, placed in con- tact with the corresponding part of the oval cartilage of the other side, runs backwards, and they form, by their union, the tip of the nose and the Columna Nasi. In the back of the ligamentous membrane there are several detached pieces of cartilage which give firmness to the structure and produce the pro- minence of the ala nasi. It is by means of these se- veral cartilages that the orifice of the nostril is kept open. The posterior nares, separated by the vomer, are oval, and do not present an outline differing much from that produced by the naked bone. At the pos- terior extremities of the inferior turbinated bones are the orifices of the Eustachian tubes placed obliquely, and large enough to admit the end of the little finger. It is not difficult to reach them with an instrument gently curved introduced through the inferior meatus of the nose. They are here partly membranous and partly cartilaginous, running upwards and outwards to the bony canal leading into the cavity of the tym- panum. The Schneiderian membrane is spread over all the bones composing the nostril, and by its thickness diminishes the foramina leading into the sinuses. Under the anterior part of the middle spongy bone is an orifice which leads through the aethmoidal cells into the frontal sinus. At the middle part of the mid- 144 OF THE HEAD AND NECK. die meatus, or that between the lower and middle spongy bones, is the opening into the Antrum High- morianum capable of giving entrance to a common quill. In the meatus formed posteriorly in the aeth- moid bone, under the cornet of Morgagni, are the orifices of the posterior aethmoidal cells; at the back part of this cornet, and a little above it, is the orifice of the Sphenoidal Sinus. Immediately under the fore part of the inferior spongy bone is the orifice of the Ductus ad Nasum. This membrane is laid smoothly on the septum of the nose. The Schneiderian or mucous membrane, when well injected, shows great vascularity; its reflections into the sinuses are not, however, so thick or vascular as the other parts of it. The surface which looks to- wards the cavity of the nose is villous like velvet, and is studded with many mucous follicles which pass ob- liquely into it, some of them being arranged in rows. It adheres closely to the bones, and that surface in the closeness of its texture resembles periosteum. Its nerves are derived from three sources. 1. The Olfactory, or Nerves of Smelling. They pass on each side of the crista galli in two rows per- forating the cribriform plate, and taking a coat of dura mater which renders them strong and fibrous. One row is spread on membrane covering the upper part of the aethmoid bone, not descending below the inferior edge of the middle spongy bone; the other is THE NOSE. 145 distributed to the membrane of the nasal septum, and its fibres descend somewhat lower. The fibrillse of these nerves terminate on the mucous surface of the membrane. 2. The Lateral Nasal Nerve comes from the Spheno Palatine Ganglion through the spheno pala- tine hole, and gives fibres to the septum and lateral parts of the nose. One of the former dips into the anterior palatine hole, joins with its fellow from the other side, and forms a ganglion near the roof of the mouth. 3. The Nasal Nerve of the First Branch of the Fifth Pair, passing through the anterior aethmoidal foramen into the cranium, dips down at the side of the crista galli into the nose, and may be traced along the nasal bone to the tip of the nose. The nose is supplied principally with blood from the internal maxillary artery and from the aethmoidal branches of the ophthalmic. Its veins accompany the arteries. T 146 OF THE HEAD AND NECK Section VI. mouth. The cavity of the mouth is chiefly formed by the palatine processes of the upper maxillary and palate bones, above; by the tongue and the muscles connect- ed with it, below; by the cheeks laterally; by the lips before, and by the soft palate behind. The Tongue has its root at the os hyoides; it is there thin, but broad; its tip and sides, owing to the lining membrane passing a considerable way under them before it is reflected to the organ, are left free. Four pairs of muscles compose its bulk. The Stylo- glossus, which arises from the anterior part of the sty- loid process, and is inserted into the side of the tongue near its root, the fibres going to the tip. The Hyo- glossus, which arises broad and thin from the cornu, appendix, and body of the os hyoides, and forms a considerable part of the bulk of the tongue on its side, as far as the tip. The Lingualis, arising indis- tinctly from the root of the tongue, on the inner side of the former muscle, and its fibres are to be traced as far as the tip. And lastly, the Genio-Hyo-glossus muscle, the most internal of the four, lying in con- tact with its fellow of the opposite side. It arises from the tubercle on the posterior face of the sym- THE MOUTH. 147 physis of the lower jaw; its fibres radiate so as to be inserted from the body of the os hyoides to the tip of the tongue. Besides these regular and well defined muscles, there are many fibres which cross the or- gan in various directions, and facilitate much its mo- tion. The superior surface of the tongue is rough from the presence of a number of eminences on it, called Papillae. At the posterior part are about nine of them, arranged like the letter V, with the point back- wards, much larger than the others. They are fixed in pits, and surrounded by a fold of the integuments; from their particular form, they have been called Pa- pillae Capitatae, or Maximae. Distributed over the tongue, and scattered at irregular distances from each other, are the Papillae Mediae, more numerous than the others, and smaller. A third class of them occu- pies, by far, the greater part of the surface of the tongue, and are called Papillae Villosae. And a fourth set of them, filling up the intervals left between the others, and being the smallest of any, are called Papil- lae Filiformes. It is probable that these papillae, ex- cept the first, are essentially connected with the func- tion of taste, as they are abundantly supplied with nerves and blood-vessels, having a peculiar arrange- ment. At the posterior part of the tongue is a fold of the membrane covering it, which rises up to join the Epi- glottis cartilage; and on each side of it is a small pouch 148 OF THE HEAD AND NECK. which occasionally produces some trouble from arti- cles of food lodging in it. A little anterior to this fold is a small blind hole, into which some mucous glands discharge their contents, called the Foramen Caecum of Morgagni. And scattered about the root of the tongue we find, many mucous glands. The lining membrane of the mouth, when the cu- ticle is separated from it by maceration, exhibits a sur- face covered with fine villi. On the lips and cheeks, under it, are situated many small glandular bodies, called Glandulae Labiales, and Buccales. It forms a fraenum where it is reflected from the upper and lower lips to the centre of the Jaw Bones. On the alveolar processes, its texture is more dense, constituting the gums, which closely surround the necks of the teeth. This membrane is also united to the lowTer side of the tongue by a fraenum, on each side of which we see the orifices of the ducts of the sub-maxillary glands. Under the tongue, at its side, and projecting into the cavity of the mouth, but covered by the lining mem- brane, is the Sublingual Gland, opening by fifteen or twenty distinct orifices. On the cheeks, opposite the interstice of the second and third molar tooth of the upper jaw, is found the orifice of the duct of the Pa- rotid Gland. The lining membrane of the roof of the mouth, is of a dense structure, having a ridge in it just under the middle palate suture, and on each side of that transverse ridges, extending towards the alveolar pro- THE MOUTH. 149 cesses. It adheres very closely to the bone, and be- neath are to be found many mucous glands of various sizes, having their excretory ducts terminating on the surface of the palate. OF THE FAUCES. At the posterior part of the mouth may be seen, very distinctly, by opening the lower jaw, an incom- plete partition which divides it from the pharynx. It is the Velum Pendulum Palati, formed by the lining membrane of the mouth reflected over several mus- cles. In the centre is a projection termed Uvula. On each side of the uvula the soft palate has its infe- rior margin terminating in two crescentic edges call- ed its lateral half arches. The anterior half arch is rather more distinct than the posterior, and arising from the side of the uvula, runs around to be insert- ed into the side of the basis of the tongue. The pos- terior half arch, arising from the side of the uvula near the anterior, runs backwards and outwards, and is lost insensibly about the middle of the pharynx. Between the half arches, on each side, is placed the Tonsil Gland, the surface of which is commonly so reticulated, that it might readily be mistaken for ul- ceration. The space between the lateral half arches is the Fauces, and the anterior opening into it, is the Isthmus of the Fauces. By dissecting off the membrane of the soft palate 150 OF THE HEAD AND NECK. which is continued from the mouth, several mucous glands are brought into view lying immediately under it, and also the muscular structure, which is as follows. 1. In the anterior half arch is the Constric- tor Isthmii Faucium, which arises from the side of the tongue near its root, and is inserted into the middle of the velum near the root of the uvula. It tends to close the opening from the mouth into the pharynx. 2. In the posterior half arch is the Palato Pha- ryngeus. It arises from the middle of the soft palate behind, near the root of the uvula, and is inserted in the pharynx between the middle and lower con- strictors and into the superior posterior part of the Thyroid Cartilage. It draws the velum palati down- wards. 3. The Azygos Uvulae arises from the posterior termination of the palate suture, runs through the cen- tre of the soft palate, and ends in the point of the uvula. It draws the uvula upwards and diminishes the breadth of the soft palate. 4. Circumflexus or Tensor Palati, arises from the spinous process of the sphenoid bone behind the foramen ovale, and from the contiguous part of the Eustachian tube, it passes in contact with the pterygoi- PHARYNX AND OESOPHAGUS. 151 deus internus muscle, and terminates in a broad ten- don below, which winds around the hook of the in- ternal pterygoid process, and is inserted into the soft palate near its middle, and into the posterior lunated edge of the palate bone. It spreads the palate. 5. Levator Palati, arises from the point of the petrous bone and contiguous part of the Eustachian tube; it is on the inner side of the former muscle, and passes downwards to be inserted into the soft palate. It draws the soft palate upwards. Section VII. OF THE PHARYNX AND OESOPHAGUS. The Pharynx is a large membranous cavity placed at the posterior part of the nose and of the mouth for opening an external communication for the cavities of the thorax and abdomen. It lies before the cervical vertebrae, being connected to them by cellular mem- brane, is closely attached to the basis of the skull before the foramen magnum, to the posterior margin of the bony face including the upper and under jaws, to the back parts of the os hyoides and of the thyroid cartilage, and below it contracts so as to be continu- ous with the oesophagus. In consequence of these 152 OF THE HEAD AND NECK. several attachments it constantly remains a patulous unoccupied cavity, having a free communication with the nostrils and Eustachian tubes above, with the mouth just below them, with the larynx still lower down, and with the oesophagus at its bottom. The lining membrane which is expanded over.it is conti- nuous with the lining membranes of these several ca- vities. To get a good view of the pharynx, the head ought to be cut off at the root of the neck and all the cer- vical vertebrae removed; the cavity being then stuffed with baked hair, we proceed to the dissection of the muscles which form it, of which there are three pair. 1. Constrictor Pharyngis Inferior, arises from the side of the cricoid and of the thyroid cartilage; it unites with its fellow in a white line in the centre of the posterior part of the pharynx. Its superior fibres are very oblique, covering the lower edge of the next muscle, and its inferior fibres are more trans- verse, being connected with the oesophagus. 2. Constrictor Pharyngis Medius, arises from the appendix and cornu of the os hyoides, and from the round ligament connecting the latter with the cornu of the thyroid cartilage. It is inserted, in the same way as the foregoing, into its fellow and into the cuneiform process of the os occipitis just before the foramen magnum. PHARYNX AND (ESOPHAGUS. 153 3. Constrictor Pharyngis Superior, arises from the cuneiform process of the os occipitis, from the pterygoid process of the sphenoid bone, and from the upper and under jaw bones behind the last molar teeth being connected with the buccinator muscle. Inserted into its fellow by a white line in the mid- dle, and having its lower edge concealed by the pre- ceding. These muscles all assist in conveying the food from the mouth into the oesophagus. The pharynx, after the dissection of these muscles, may be cut open vertically at its back part, when a very satisfactory view of all the cavities connected with it will be obtained. > THE 02S0PHAGUS. ' This is a tube leading from the pharynx to the sto- mach, it is placed between the trachea and cervical vertebrae above, passes into the thorax between the laminae of the mediastinum and in contact with the dorsal vertebrae, penetrates through the left foramen of the diaphragm and terminates in the cardiac ori- fice of the stomach. (See posterior mediastinum). The (Esophagus is formed of three coats, the mus- cular, the nervous and the mucous. When distended it is cylindrical, but larger above than below. The muscular coat is very strong, consisting of two planes of fibres, the external being longitudinal and the in- u 154 OF THE HEAD AND NECK. ternal circular. The nervous coat connects together the other two; it is formed of loose cellular membrane which allows them to move very freely upon each other, and conducts the blood-vessels through their structure. The mucous coat is a continuation of that of the pharynx, it is covered by a very delicate cuti- cle, which is continued into the stomach, and forms in some animals an abrupt and well marked termination just at the cardiac orifice. The internal coat of the oesophagus is most frequently found in longitudinal folds, which are removed by its distention; it abounds with mucous follicles, and is well furnished with blood- vessels. Section VIII. OF THE LARYNX. By the term Larynx is understood the irregular cartilaginous tube and its contiguous structure which forms the upper termination of the windpipe. The basis of the structure is five distinct cartilages, and a crooked bone the os hyoides; which is intermediate to the larynx and the tongue, serving the purposes of both. The Os Hyoides resembles much the letter U, di- visible into its basis or curved part and its cornua or THE LARYNX. 155 lateral projections. It is parallel with the lower jaw and about half an inch below it. It acts as a root to the tongue, as two arms in holding out the bag-like orifice of the Pharynx, and from it is suspended the Larynx. The base of the os hyoides is broad and convex anteriorly, above it is flattened on each side by the insertion of muscles from the lower jaw, and at its posterior part it is excavated sufficiently to re- ceive the tip of the little finger. At the ends of the base the two cornua arise, separated from it by car- tilage and therefore moveable; they are about an inch long, somewhat flattened, and have a tuberculated ter- mination behind. On the cartilaginous interval of each side, is placed a bony body about the size of a grain of wheat, the Appendicula, which stands up ob- liquely towards the styloid process and is connected to its tip by a round ligament resembling a nerve; this ligament in some cases has been found ossified in the greater part of its length. The five cartilages of the Larynx are the Thyroid, Cricoid, two Aryte- noid, and the Epiglottis. The Thyroid Cartilage, (C. Thyroidea,) is about an inch below the os hyoides, and forms a very striking prominence in the male neck. It consists of two flat sides which are symmetrical, and united to each other by an angle slightly acute at its anterior part; the upper place of union forms the projection called Pomum Adami. The sides of this body lean 1 156 OF THE HEAD AND NECK. over somewhat, by which its transverse diameter above is somewhat larger than that below. The upper edge is notched in front, and terminates behind by a long process on both sides termed Cornua Majora, which look towards the ends of the cornua of the os hyoides and are connected to them by round liga- ments. The inferior edge is somewhat incurvated, and terminates behind by a short process on both sides, the inferior cornua, or Cornua Minora, by which it is fastened to the sides of the cricoid carti- lage and establishes a centre of motion between the two. The Cricoid Cartilage, (Cart. Cricoides,) is an oval ring of unequal breadth and thickness placed im- mediately below the thyroid cartilage. Its lower mar- gin is horizontal and affixed to the first ring of the trachea; the upper margin is very oblique, rising from before backwards, till the breadth behind is, three times as great as that before. In front the cricoid cartilage is thin, behind it is thick. On the upper edge behind, on each side, a little head or convexity is formed for establishing a sort of ball and socket joint with the arytenoid cartilages. The interior sur- face is flat, the exterior is marked by the muscles which lie on it. The Arytenoid Cartilages, (Cart. Arytaenoideae, Triquetrae,) two in number, one on each side of the THE LARYNX. 157 upper back part of the cricoid, resemble each a tri- angular pyramid curved backwards and having an excavated base. The internal sides of the two face each other, and by the action of their muscles may be brought together; when thus joined they resemble the spout of a pitcher. On the top of each is a little car- tilaginous tubercle about the size of a grain of wheat, (Corniculum Laryngis,) which is included in the soft parts and is extremely moveable. There is a regular articular cavity between the cricoid and arytenoid cartilages. The Epiglottis Cartilage, (Epiglottis,) is an oval disk with an elongated pedicle below, its upper edge being thin and rounded. It is fixed behind the base of the os hyoides and the thyroid cartilage, and has its pedicle connected to the entering angle on the poste- rior face of the latter. The flat surfaces of this car- tilage present forwards and backwards, and are above the level of the arytenoids; from this position of the epiglottis it is said to be placed as a valve over the opening of the larynx; its valvular office, however, I have great cause to disbelieve, for subsequent rea- sons. It is very elastic, having a fibro-cartilaginous structure, and is perforated with many foramina giv- ing it a cribriform appearance. The upper edge of the Thyroid Cartilage is con- nected to the internal edge of the Os Hyoides, by a thin and somewhat elastic membrane which fills up 158 OF THE HEAD AND NECK. the whole of this interval, and completes the front and lateral parietes of the Larynx. Between this membrane and the cavity in the base of the Os Hy- oides, is a small sac, very rarely mentioned by anato- mists, and considered by such as speak of it, as a Bur- sa Mucosa. I have never seen a fluid in it corre- sponding to that of the Bursae; and without previous knowledge on the subject, was induced to look for it in the human subject, from its existence in monkeys. It has no connection with any other cavity, and is occasionally the seat of disease. Its natural secre- tion being converted into a meliceris, it is disposed to ulcerate, and form a fistulous sore in the neck, not to be cured except by extirpation. This remark, on its disease, I have got from Dr. Physick, in whose prac- tice it is not uncommon; and lately, I have seen him operate for it in the encysted state. Between the Epiglottis and the Thyroid Cartilage, and on the posterior face of the Thyreo-hyoid mem- brane, is a quantity of loose fatty matter intermixed with small mucous glands; the perforations in the Epi- glottis are supposed to conduct the excretory tubes of the latter into the Larynx. Between the Thyroid and Cricoid cartilages, in front, there is a ligamentous membrane which fills up this interval; it is the Crico-thyroid membrane, and in Laryngotomy, is indicated as the proper place for this operation. From the anterior part of the base of each Aryte- THE LARYNX. 159 noid cartilage, a ligament passes horizontally to the entering angle of the Thyroid. These ligaments are not parallel, but converge from the Arytenoid carti- lages, and are very near each other in front. At the distance of three lines above these, are two other li- gaments passing also horizontally from the Arytenoids to the thyroid cartilages; they are more parallel, but have not their ligamentous character so well defined. There are several pairs of muscles belonging to the Larynx. 1. The Crico-Thyroideus, arises tendinous and fleshy from the anterior lateral surface of the cri- coid cartilage, and passes upwards and backwards, to be inserted into the inferior cornu of the thy- roid cartilage, and the adjacent part of its inferior edge. Use, to draw these cartilages obliquely to- gether. 2. The Thyreo-Hyoideus, arises obliquely from the side of the thyroid cartilage externally, and is in- serted into part of the base, and nearly all of the cor- nu of the os hyoides. Use, to approximate these two bodies. 3. The Crico-Arytenoideus Posticus, arises from the back of the cricoid cartilage, occupying its excavation, and is inserted into the posterior part of 160 OF THE HEAD AND NECK. the base of the arytenoid cartilage. To draw the arytenoid backwards, and make the ligaments tense. 4. The Crico-Arytenoideus Lateralis, arises from the side of the cricoid cartilage, and is inserted into the side of the base of the arytenoid. Use, to draw this cartilage outwards, and open the chink of the glottis. 5. The Thyreo-Arytenoideus, arises from the posterior face of the thyroid cartilage, and the liga- ment connecting it with the cricoid, and is inserted into the anterior edge of the arytenoid cartilage. Use, to relax the ligaments of the glottis. 6. The Arytenoideus Obliquus, arises from the base of one arytenoid cartilage, and is inserted into the tip of the other. It is a very small fasciculus, and sometimes only one muscle exists. Use, to close the chink of the glottis. 7. The Arytenoideus Transversus, arises pos- teriorly from the whole length of one arytenoid carti- lage, excepting a little part of the tip, and is inserted in a corresponding manner, into the other. Use, to close the chink of the glottis. 8. The Thyreo-Epiglottideus, arises by a few fibres, from the posterior face of the thyroid carti- THE LARYNX. 161 lage near its entering angle, and is inserted into the side of the Epiglottis. Use, to draw the Epiglottis downwards. 9. The Aryteno-Epiglottideus, arises by a few indistinct fibres, from the superior lateral parts of the arytenoid cartilage, and is inserted into the side of the Epiglottis. Use, to draw the Epiglottis down- wards. These two last muscles are generally so small and undefined, that they cannot be satisfactorily distin- guished from the adjacent soft parts. The cavity of the Larynx is lined by a continua- tion of the mucous membrane of the Pharynx. This membrane, where it establishes the upper boundary of the Laryngeal cavity, forms a fold on each side, extending from the Epiglottis to the Arytenoid Car- tilage; it then sinks into the cavity beneath. In ex- tending from the upper to the lower ligament of the glottis, on each side, it forms a pouch between them, called the ventricle of Galen or Morgagni. From the lower ligament this membrane passes to line the Cricoid Cartilage, and thence into the Trachea. The fissure between the two lower ligaments, is the Rima Glottides; and the cavity above the upper ligaments is the Glottis. For an account of the Trachea, see the article Thorax. Notwithstanding the Epiglottis is considered as a x 162 OF THE HEAD AND NECK. valve which shuts over the larynx in swallowing and prevents articles of food from descending into it, I am much inclined to doubt the entire correctness of the opinion; for there is no muscular apparatus in the structure capable of producing this position, and, therefore, where it does occur, it must depend essen- tially on the mechanical pressure of the morsel which we swallow. But this explanation does not account for our ability to swallow fluids, or to swallow a very small body, as a crumb of bread; neither does it ac- count for the manner in which the larynx is protect- ed in vomiting. It is more than probable that in all these acts the motion of the larynx is the same. Al- ways impressed with the insufficiency of these doc- trines, and knowing also that they had been rendered still more questionable by cases in which the upper part of the epiglottis had been lost by wounds or ul- ceration, I remained unsatisfied till very lately. The last spring, in dissecting a muscular subject, I had oc- casion to observe a position of these parts which will account for all. The upper part of the glottis was closed, but in a manner precisely the reverse of the received opinion; the epiglottis, instead of being drawn down over this opening, had the opening drawn up to it. The natural position of the epiglottis is not vertical, but somewhat obliquely backwards. Consi- dering the upper opening of the larynx as constituted by a plane passing from the tip of the arytenoid car- tilages along the superior line of the cricoid cartilage, THE LARYNX. 163 we shall then have a surface which, by being brought somewhat obliquely forwards, will come in contact with, or nearly so, and be parallel to the posterior face of the epiglottis, while the latter is in its natural po- sition. It is, I believe, in this manner that the upper opening of the windpipe is closed, nor are we defici- ent in pointing out the agent. By examining the po- sition and strength of the crico-thyroid muscle it u ill be obvious that the shortening of the larynx, which this muscle is said to produce, is, in a strict analysis of it, no other motion than what I have just describ- ed. If the glottis be protected in this way it shows satisfactorily why the soldier, mentioned by Larrey, whose epiglottis was cut off by a musket ball, when the wound cicatrized, could swallow as well as usual, and why such as have the upper part of the epiglot- tis cartilages removed by venereal ulceration suffer no inconvenience from it of consequence. PART II. OF THE TRUNK. CHAPTER I. Of the Thorax. The dissection of the cavity of the Thorax should be preceded by that of the muscles which lie upon its front part and sides. Section I. OF THE MUSCLES. The Pectoralis Major is the most superficial, forming the large and swelling cushion of flesh under the skin of the breast. It arises tendinous from the anterior face of the sternum, its whole length, fleshy from the cartilages of the fifth and sixth ribs, and by a fleshy slip from the upper part of the tendon of the external oblique muscle. It arises also fleshy from MUSCLES OF THE THORAX. 165 the interior two-thirds of the clavicle. The clavicu- lar and sternal portions of the origin are separated by an interval, giving the appearance of two muscles. The fibres converge and terminate by a broad, thin tendon, which is inserted into a roughness on the ex- terior edge of the fossa of os humeri for the biceps tendon. The under edge of the muscle, near its in- sertion, is folded inwards, which gives the rounded thick margin to the fore part of the axilla. That part of the broad tendon belonging to the clavicular portion of the muscle is inserted lower down than the sternal, which produces a decussation of the fibres of the tendon. The Pectoralis Major moves the arm upwards and inwards. 2. The Pectoralis Minor is brought into view by raising the last muscle. It is comparatively small and somewhat triangular, arising by thin tendinous digitations from the upper edges of the third, fourth, and fifth ribs. It soon becomes fleshy, and is insert- ed, by a short flat tendon, into the inner facette of the coracoid process of the scapula. Its use is to draw the scapula inwards and downwards. 3. The Subclavius is a small muscle placed im- mediately under the clavicle, arising from the carti- lage of the first rib, and inserted into the inferior face of the clavicle from near the sternum to the conoid 166 OF THE TRUNK. ligament, which connects the coracoid process and the clavicle together. It draws the clavicle down- wards. 4. The Serratus Major Anticus is a broad mus- cle lying on the sides of the ribs, between them and the scapula, and arising from a line anterior to their middle. In well defined bones the precise points of origin are readily seen. It arises froni the nine up- per ribs by fleshy digitations, the Superior one of which seems almost like a distinct muscle, the five lower are connected to the obliquus externus abdo- minis, the digitations of the two muscles interlocking with each other. The fibres >con verge, and are in- serted into the base of the scapula its whole length. Its action is to draw the scapula forwards. 5. The Intercostales fill up the spaces between the ribs. There are two in each space. The Exter- nal arises from the spine and from the inferior acute edge of each rib almost to its cartilage, and is inserted into the superior rounded edge of the rib below for the same distance, its fibres passing obliquely forwards. The Internal Intercostal, arises from the inferior edge of the rib, beginning at the sternum, and going back- wards to the angle of the rib, it is inserted into the superior rounded edge of the rib below on its inner side, its fibres passing obliquely backwards. They draw the ribs together. MUSCLES OF THE THORAX. 167 6. The Levatores Co^tarum are twelve on each side, and seem to belong to the external intercostals. Each one arises from a transverse process, and is in- serted into the first or second rib below. The supe- rior one arises from the transverse process of the last cervical vertebra, and is inserted into the rib below near its tubercle; the remainder arise from the trans- verse processes of the dorsal vertebrae. The three or four last are inserted into the second rib below their origin, which circumstance induced Albinus to divide them into Levatores Costarum Longiores et Breviores. As their name expresses, they elevate the ribs. These muscles are best seen in the dissection of the back. With a view to examine the cavity of the thorax, the sternum along with the cartilages of the ribs, (their whole length being preserved,) is to be taken out. We then see, on their inner faces, a muscle called 7. Triangularis Sterni, which arises from the whole length of the cartilago ensiformis at its edge, and from the inferior half of the edge of the second bone of the sternum. The fibres go obliquely up- wards and outwards to be inserted into the cartilages of the third, fourth, fifth and sixth ribs by fleshy and tendinous digitations. Its use is to depress the ribs, and consequently to diminish the cavity of the thorax. 168 OF THE TRUNK. Section II. viscera of the thorax. The most usual manner of getting into the cavity of the Thorax is that just mentioned ; but there is a much better one introduced here, by the late Profes- sor Wistar, in which the five middle true ribs on each side are removed, all the rest with the sternum being left. This plan gives an excellent view of the seve- ral viscera, and also of their relative situation and extent; and it is such as I would recommend the student to adopt, in at least one dissection. The principal objection to it is, that it renders the upper parts of the trunk unfit for farther investigation, in- asmuch as the superior extremities must be removed in the first place. If the muscles connecting the up- per extremities to the trunk, on its fore and back parts, should have been previously dissected, this ob- jection is no longer valid. Approaching the cavity of the thorax, by either of the methods mentioned, we see at once its most strik- ing contents, viz. the Heart and Lungs, each covered by its appropriate membrane, the heart being between the sternum and the dorsal vertebrae; the lungs on each side of it, in a healthy state, always collapsing when the thorax is opened. Tb^re are two lungs, a VISCERA OF THE THORAX. 169 right and left, which are perfectly distinct from each other. Each lung has its appropriate membrane, called Pleura; which covers its external surface, and giving it a glistening smooth appearance, is reflected from the internal face of the lung over the proper mem- brane of the heart to the sternum before, and is re- flected to the spine behind. The membrane then lines the ribs, intercostal muscles and diaphragm, of that side of the thorax to which it belongs. Above, it passes up as high as the head of the first rib, and below, it goes as low down as the last rib. That part of the pleura which covers the lung, is the Pleu- ra Pulmonalis, and that which lines the ribs, the Pleura Costalis. As the pleurae are bags, one on each side of the thorax, it is very demonstrable that the contiguous faces of them form a septum, which extends from the sternum in front to the spine behind, and from the upper part of the thorax to the diaphragm. The heart is placed in the middle of this septum. Between the heart and sternum is the Anterior Mediastinum; be- tween the heart and spine is the Posterior Mediasti- num; and between the heart and the upper part of the thorax, is the Superior Mediastinum; each of which merits strict attention. It is obvious then, that the septum consists of two laminae, one from each pleura. These two la- minae are somewhat separated, where they are called 170 OF THE TRUNK. Anterior Mediastinum, by the remains of the thymus? gland above, and by adipose and cellular membrane below. The anterior mediastinum is attached to the middle of the sternum, except at its lower part, where it inclines somewhat to the left side. To get a good view of its contents, the sternum must be sawed through longitudinally, and the two halves separated an inch by a small block of wood. The contents of the posterior mediastinum and of the superior, are best seen and understood at a subsequent stage of the dissection. The Pleura is a thin and transparent membrane connected to the parts on which it lies by a short cel- lular substance. No red vessels, in its healthy state, are to be observed. In the young subject, it is free from adeps; but in advanced life, attended with cor- pulency, considerable masses of fat are found in the anterior mediastinum, and between it and the pericar- dium. The exhalent vessels of the pleura are derived from the intercostal, internal mammary, phrenic, and some other arteries, and secrete a fluid which lubri- cates its surface. Between the pleurae, and under the sternum, is the Pericardium, containing the heart. It is a white, se- mitransparent membrane, of a condensed fibrous structure, possessed of little or no elasticity, which renders it highly appropriate for sustaining the action of the heart in its dilatation. It is a complete sac, consisting of two laminae, and VISCERA OF THE THORAX. 171 '& reflected over the surface of the heart, so as to give it an investing membrane. This investment com- mences at the back part or base of the heart, and is continued over the whole of it, being extended on the aorta to the branches which arise from the top of its curvature; on the pulmonary artery to its bifurcation; on the pulmonary veins to their first branches; on the ascending cava to the diaphragm; and on the descend- ing cava to the middle of the space between the en- trance of the Vena Azygos and the Transverse Vein. The exterior lamina has not these reflections, it is only united to the several parts where the reflections commence. An analogy is observable in this arrange- ment with the membranes of the joints; the exterior lamina of the pericardium corresponding with the capsular ligament, and the internal lamina with the synovial membrane. It is the exterior membrane which supports the heart, and the interior which fur- nishes the lubricating fluid, found in general in the pericardium, to the amount of a drachm. The ante- rior part of the pericardium lies loosely on the heart. The pericardium is attached strongly, by all its infe- rior surface, to the tendon of the diaphragm. the heart. The Heart is a hollow muscle consisting of four cavities, two auricles, and two ventricles. Its shape is somewhat conical, but flattened on one surface. 172 OF THE TRUNK. The base of the cone is formed by the auricles, the body by the ventricles, and the apex by the point of the left ventricle projecting beyond that of the other. The heart being fixed as mentioned between the ster- num and the dorsal vertebrae, has its base turned ob- liquely towards the right side, and its apex about the junction of the fifth rib with its cartilage. Its flat part reposing on the flat tendon in the centre of the diaphragm is on a horizontal line, or nearly so, with the inferior end of the second bone of the sternum. The heart, in consequence of being tied down to the diaphragm by the pericardium, is, excepting its pulsa- tions, exposed to but little motion, and is therefore almost uniformly in the same position. It has, between the internal membrane of the pericardium and its own substance, more particularly along the course of the coronary vessels, adipose matter in great abundance in old subjects, and this adipose matter sometimes penetrates so deeply between the fasciculi of its fibres as to give them a very loose texture, and apparently to disqualify them in some measure from performing their functions. The parietes of the heart are formed principally of muscular fibres, which are variously arranged; some pass spirally around the heart, others in an irregular and indeterminate manner, but all in such a direction as to concur, by contracting, in effacing its cavities. The cavities are lined by a smooth elastic membrane which is a continuation of, and resembles the internal VISCERA OF THE THORAX. 173 coat of the arteries and veins. Between the auricles and ventricles, and at the orifices of the great arteries, this membrane is raised up and reflected so as to con- stitute valves. The heart is divided into Right and Left Sides, each consisting of an auricle and of a ventricle. The Right Auricle receives the two great trunks of the Venous System, the Ascending and the Descending Vena Cava. The Left Auricle receives the pulmo- nary veins. The Right Ventricle sends off the Pul- monary Artery, and the Left Ventricle the Aorta. The Right Auricle, situated at the right posterior part of the heart, is an oblong cavity about a line in thickness. To view its internal arrangement it should be slit open in front from cava to Cava, we shall then see that its posterior surface is smooth and is formed by a continuation of the structure of the great veins, which meet each other at an obtuse angle, and form a projection into the auricle. This last circumstance, connected with a slight thickening of the part, has given occasion to the name Tuberculum Loweri. Anteriorly the auricle is swelled into a pouch in which the muscular fibres, instead of being uniformly spread into a coat, are collected into fasciculi lying parallel to and near each other; they are called Mus- culi Pectinati. At the upper part of the sinus is the proper auricular portion of the cavity, whence it got its name; it is not marked by any peculiarity except that the musculi pectinati prevail in it. The auricles 174 OF THE TRUNK. have a common septum, and in it, just below the tu- berculum loweri, is situated the Fossa Ovalis, which in the foetal state was an opening between the auri- cles, and indeed at the upper part of this depression we often find a foramen large enough to admit a probe into the left auricle, in subjects advanced into old age. The edges of the fossa ovalis are elevated and thickened, being the Columnae or Annulus Fossae Ovalis. Beneath the fossa ovalis is the Eustachian valve. It is formed by a duplicature of the lining membrane of the auricle and of the ascending cava, being spread somewhat obliquely across the orifice of the latter. It is of a crescentic shape, about half an inch wide, but occasionally reticulated, and commences at the left pillar of the annulus ovalis; it terminates anteriorly about the junction of the auricle and the vein. It is connected by its convex edge to the parietes of the au- ricle, and its concave or floating edge looks somewhat upwards. Just before and below the Eustachian valve is another much smaller, but also seminulated. which covers the orifice of the coronary vein. At the left of the right auricle is an opening of more than an inch in diameter, the Ostium Venosum, through which it communicates with the right ven- tricle. In the right auricle are many small orifices of co- ronary veins called Foramina Thebesii; they also ex- ist in all the other cavities, but are not so numerous VISCERA OF THE THORAX. 175 there. They are said to be particularly conspicuous in cases of diseased lungs. The next cavity to be examined is the Right Ven- tricle; to expose it satisfactorily it should be divided extensively along the septum ventriculorum superi- orly and inferiorly. It is of a triangular form, and its sides are much thicker than the sides of the auricle, as they measure, most commonly, about three lines. Its internal surface is very irregular and rough, the muscular structure of it being thrown into project- ing columns of very indeterminate figures, arrange- ment, and dimensions. Some of them jut out, and are connected to the valves at the ostium venosum by in- termediate tendons; others pass from one side of the ventricle to the other, and a third series present a re- ticulated appearance, lying on the face of the ventri- cle and connected with it. Their general object is to strengthen the ventricle, to enable it to expel its con- tents entirely, and to agitate well and mix the blood. The Ostium Venosum has a tendinous margin, from which is reflected the lining membrane of the ventri- cle, so as to form a broad fold surrounding it. This fold being eight or ten lines wide, is irregularly divid- ed at its floating edge, into three parts, whence the name of Tricuspid Valve has been given to it. The tricuspid valve, situated in the ventricle, has its mar- gin attached to the round tendinous chords just men- tioned, called the Chordae Tendineae, which again arise from the Columnae Carneae. These tendinous 176 OF THE TRUNK. attachments of the tricuspid valves prevent them from being thrown into the auricle when the ventricle con- tracts. At the upper part of the ventricle is the orifice of the pulmonary artery, which conveys the blood to the lungs; provision for it is made by the upper part of the ventricle becoming smooth. The orifice of the artery is round, and about twelve lines in diameter. From the internal surface of the artery, a little be- yond its orifice, three valves arise, called Semilunar, which may be compared, each to a semicircular plane, connected by its circumference, to a cylindri- cal cavity. The diameter of the plane is loose; in the centre of it, is a small cartilaginous body, the Corpusculum Aurantii; and on each side of the cor- pusculum, the diameter of the valve, instead of being a straight line, is slightly festooned. The valve is al- most diaphanous, and seems to be produced by a re- flection of the lining membrane of the artery. Be- tween the coats of this reflection is, however, to be found another substance very much like that of the artery, which also forms a festooned edge a little be- low the one just described. As the three valves are placed in a row surrounding the artery, in its action they are thrown down, forming thereby a complete septum against the return of the blood into the ven- tricle ; and the Corpusculum Aurantii being in the mid- dle of each form a point d'appui or abutment at which the edges of the valves support each other. Between VISCERA OF THE THORAX. 177 the outer face of the valve and the internal face of the artery a pocket, attended with a dilatation of the arte- ry, is formed, called the Sinus of Valsalva. The Pulmonary Artery is a large white fibrous tube given off in the manner mentioned; under the arch of the aorta, it divides into two branches of equal mag- nitude, right and left, which go to the lungs of their respective sides. The right branch passes under the arch, and is then minutely distributed to the lung. The left is in front of the descending aorta, and is dis- tributed to the left lung with equal minuteness. The blood is brought from the lungs by the pulmo- nary veins, which are four in number, two on each side. The branches constituting the trunk of each of these veins, are generally united before the trunk pe- netrates the pericardium. This trunk afterwards unites to the auricle at one of its corners. The Left Auricle has about the same cubic con- tents with the right, but differs from it somewhat in its figure, by being more square. Its broad internal surface looks towards the spine. It is fixed to the pos- terior part of the left ventricle, and is divided like the right auricle, into the Sinus Venosus, sometimes call- ed Sinus Pulmonalis, and into Proper Auricle. The latter is situated at the left side of the aorta, and is somewhat longer, narrower, more crooked, and more notched at its margins than the other proper auricle. z 178 OF THE TRUNK When the left auricle is cut open, which should be done by a slit down its middle, it will be perceived that its parietes are thicker than those of the right, and that both externally and internally, its surfaces are perfectly smooth, except in the proper auricular part, where the Musculi Pectinati prevail. The Septum between the auricles, viewed on this side, is smooth, not presenting any remarkable ap- pearance; when held up to the light, it is seen to be thinner and more transparent at the place correspond- ing with the fossa ovalis of the other side. At the anterior and inferior side of the auricle is its ostium venosum, communicating with the left ventricle. It has a tendinous margin, and is rather more than an inch in diameter. The Left Ventricle differs from the right in shape, being more conical. It is equally capacious. Its anterior part constitutes the apex of the heart, and strikes against the ribs. The best mode of examin- ing its cavity is to make an incision through its parie- tes near the septum, and to separate it completely on that side from its fellow. Another incision should be made so as to detach it from the auricle, also, near their septum. The latter cut is to be executed with particular care, so as to avoid wounding the interior structure. That done, we see its general arrange- ment within, corresponding with the right ventricle. The parietes of this ventricle are eight lines through, being about three times as thick as the other. Itb VISCERA OF THE THORAX. 179 columnae carneae are larger and stronger, but arrang- ed on the same principle, some passing from side to side of the cavity, others being reticulated and easily raised up from the part of the ventricle on which they lie, and a third set being accessory to the valvu- lar apparatus at the ostium. The Mitral Valve exists at the left ostium venosum, and is formed by a duplicature of the lining membrane of the ventricle. It is partially divided into two parts, which are pointed at their edges. Its columnae car- neae are numerous and strong, and its chordae tendi- neae are of corresponding characters. The mitral valve prevents the regurgitation of blood into the au- ricle, and is so placed that the upper half of it, when the blood is rushing into the ventricle, conceals the orifice of the aorta. Towards the orifice of the aorta, which is at the posterior superior part of the ventricle, the surface of this cavity is smooth to facilitate the passage of blood. The septum between the ventricles is of the same thickness with the left ventricle; it is formed partly by the right ventricle, but principally by the left. The Mouth of the Aorta is about an inch in di- ameter, and is furnished with three Semilunar Valves, Corpuscula Aurantii, and Sinuses of Valsalva, after the same manner with the pulmonary artery, so that the description of one will suit the other with the addition that those parts of the aorta are stronger and more 180 OF THE TRUNK. developed. The coats of the aorta are nearly three times as thick as those of the pulmonary artery, to qualify it for bearing the increased pressure of the blood. At the upper part of its curvature the aorta is dilated, to form the large Sinus of Valsalva. The aorta lies first at the back of the pulmonary artery, it then gets to its right, being between it and the su- perior vena cava; part of it is there to the right of the spine, it then makes its arch which brings it to the left of the spine and in contact with it about the third dorsal vertebra. The superior part of its arch is about eight lines below the upper edge of the sternum. The heart being a mere machine for propelling blood, requires another source for its nourishment besides the fluid circulating through its great cavities; this is furnished by the Coronary Arteries, which are two in number. The first, called Right Coronary, becomes visible between the pulmonary artery and the right auricle, and passing on the septum between the right auricle and ventricle, extends around the heart to its flat side, distributing branches to the con- tiguous parts which, for the most part, pass off at right angles. The second, or Left Coronary Artery ap- pears between the pulmonary artery and the left au- ricle; before it has become very obvious, it divides into two branches, one passes on the septum ventri- culorum to the apex of the heart; the other winds on the septum between the left auricle and the left ven- VISCERA OF THE THORAX. 181 tricle, and some of its branches pass on the flat sur- face of the heart to its apex. The Coronary Veins receive the blood of the coro- nary arteries; a common trunk is formed by them, which passes for some distance on the septum, between the left auricle and ventricle, and then opens into the right auricle just anterior to the Eustachian Valve, at the spot already indicated. of the lungs. The Lungs occupy, by far, the greater part of the cavity of the thorax, and consist of two distinct bodies placed on each side of the heart, from which cir- cumstance they are called right and left Lung. Their external shape and dimensions, with an incon- siderable exception, are the same, as they correspond in their periphery with the symmetrical sides of the thorax. The apex of the heart, from being pushed into the lung of the left side, gives the surface to- wards the mediastinum, a somewhat different figure from the lung of the right side. Each lung is divided by deep fissures into lobes; the right lung has three lobes, the left two. To ap- preciate the extent and form of the lung, it must be recollected that the cavity of the thorax is much deep- er behind than it is before; the vertical diameter before, amounting only to the length of the two upper bones of the sternum, whereas the same diame- 182 OF THE TRUNK. ter behind, implies the whole length of the column formed by the dorsal vertebrae. The figure of each lung is also modified by the convexity of the Dia- phragm; for this body, extending from the lower point of the dorsal vertebrae obliquely upwards to the end of the second bone of the sternum, would, if it were only a plain surface, influence the contiguous faces of the lungs so as to make them resemble, when united, the inferior part of an ox's hoof; but this resemblance is much increased by the diaphragm forming a convex- ity towards the thorax, which rises much above what its plane would. The similitude of the lungs to the ox's hoof, with the back part foremost, is therefore sufficiently exact for anatomical comparison, and particularly as it regards the inferior surface of the lungs. The lung lies loose every where, except at the sur- face corresponding to the side of the basis of the heart; here it is attached to the heart by the pulmonary veins, pulmonary artery, and by a branch of the tra- chea. These tubes constitute the Root of the Lung, and over the root is reflected the pleura from the pe- ricardium. The pleura which covers the root of the lung is extended downwards, under the name of Lateral Ligament, and serves to fix the posterior edge of the lung to the vertebrae, as low down as the dia- phragm. The structure of the lung is of extreme delicacy. It consists of small cells which are the ultimate ter- VISCERA OF THE THORAX. 183 minations of the bronchium. The Bronchium may be compared to the stalk of a bunch of grapes, and the cells of the lungs to the fruit; each grape, which is the cell, adhering to its pedicle or stem, which is a ramification of the Bronchium. On these cells the pulmonary artery and vein ramify very minutely, for the purpose of airing the blood. These cells are in contact one with the other, and are kept together by common cellular membrane, such as forms the me- dium of connection for other parts of the body. The lung of the bullock exhibits this structure better than the human lung, and in it we also see, by a little tearing of the parts asunder, the manner in which each lobe is divided into Lobuli or smaller lobes, which again are constituted by the cells of the lung. These lobuli are well seen in the foetus, and in very young subjects. The term Bronchia is given to the two parts result- ing from the bifurcation of the Trachea. The latter is a tube almost cylindrical, which passes in front of the oesophagus and of the vertebrae, from the inferior part of the larynx to the third dorsal vertebrae; it there divides into the Bronchia, and is placed between the pleurae of the two sides of the thorax. The right Bronchium is shorter, larger, and less slanting than the left; it sinks below the pulmonary artery, and pe- netrates the lung opposite to the fourth dorsal verte- bra; the left being long and narrow, enters the lung below the pulmonary artery, opposite to the fifth dor- 184 OF THE TRUNK. sal vertebra. The Bronchia then divide and subdi- vide through the structure of the lung, till the ulti- mate extremities of the tube terminate in the air cells. The Trachea preserves its cylindrical shape, and is kept open by a cartilaginous structure, which is composed of from sixteen to twenty pieces, more or less distinct from each other: some being separat- ed entirely; some united to the contiguous ones by their middle, and others by their extremities. Thus arranged, the cartilages form about two-thirds of the circumference of a circle, occupying the front of the trachea, and giving it the appearance, anteri- orly, of a cartilaginous tube. The remaining third is membranous. The cartilages of the trachea are de- posited in a kind of Perichondrium, possessed of ex- treme elasticity, which has continually a tendency to approximate the cartilages, and is resisted only by the attachments of the two extremities of the trachea. The effect of this elasticity is demonstrated in the living body by attempts at suicide, where the trachea being cut through, so great a gap is made in the throat that it presents the appearance of a part hav- ing been removed. The deficiency at the back part of the cartilages, is filled up by a continuation of this elastic membrane. On the interior surface of this membrane, transverse muscular fibres are placed, passing between the extremities of the cartilages, and in their contraction bringing them towards each other. The trachea is lined by a continuation of the VISCERA OF THE THORAX. 185 membrane which covers the mouth; it is perforated with a great number of holes through which the mu- cus passes. Under the membrane are many glands, from the size of a millet-seed to that of the head of a small.pin; these glands have their excretory tubes terminating in the orifices just mentioned. At the lower end of the trachea, and about the root of the lungs, is found the commencement of a chain of glands which follows, for some distance, the bronchia. In the adult they are black, numerous, and vary from the dimension of a large pin's head to that of a kidney bean. No excretory ducts are found belonging to them, and anatomists generally consider them as lymphatic. The bronchia, in dividing, still preserve, for some length, the cartilaginous structure of the trachea, but as they approach their termina- tions the deficiency at their back part ceases and the cartilages form sections of circles which produce, by the apposition of several of them, complete cylinders. This arrangement holds till finally the cartilaginous structure ceases, and only membrane is left. It is probable, from the elasticity of the lung and from its collapsing when the thorax is opened, that the elastic membrane, in which the cartilages are deposited, forms the essential cellular structure of this organ on which the blood-vessels are ramified. The lungs are furnished with nutritious vessels from the aorta called Bronchial Arteries; they follow the course of the bronchia and communicate freely a a 186 OF THE TRUNK with the pulmonary arteries; notwithstanding the lat- ter they have their proper veins, which empty on the right side into the vena azygos, and on the left into the subclavian vein. The bronchial veins also com- municate freely with the pulmonary veins. While studying the contents of the thorax it is of the first importance to attend to the relative situation of the parts included in the description. One of the most useful and interesting points is the space be- tween the two upper ribs, bounded laterally by the pleurae, anteriorly by the sternum, and posteriorly by the upper dorsal vertebrae, and having the top of the pericardium for its basis. This cavity is too irregu- lar to admit of comparison with any thing else with- out a hazard of communicating false ideas of its shape. The course of the pleura, on each side, must be well attended to, and in order to understand it, the obli- quity of the first rib must be taken into consideration. Considering the spine as a vertical column, the first rib, so far from being horizontal, is, in a majority of subjects, inclined downwards so much, that it makes an angle of about forty-five degrees with the spine; and the pleura, being reflected from the internal edge of the first rib from its head to its front part, will, of course, observe a similar obliquity. It is probably this circumstance which Sabatier, Soemmering, and Colles allude to when they speak of the pleura rising above the level of the first rib. This arrangement should influence the considerations arising from a wound in VISCERA OF THE THORAX. 187 the lower part of the neck, as a ball or sword passing through horizontally just above the sternal end of the clavicle, would certainly enter the cavity of the pleura in a great number of persons. In this upper section of the mediastinum, just at the upper edge of the sternum, are the remains of the Thymus Gland, much shrivelled, and having a liga- mentous feel with a light pink colour. In contact with the pleura on the right is the Descending Vena Cava. The common trunk of the left subclavian and internal jugular, after crossing, by an oblique de- scent, the upper portion of the sternum, joins the de- scending cava about an inch above the place where the latter penetrates into the pericardium. Behind this transverse vein is the top of the arch of the aorta and the origin of the Arteria Innominata, the left Carotid, and the left Subclavian. The oesophagus makes a vertical descent just before the dorsal verte- brae, the trachea is placed before it, and we see the arteria innominata crossing the latter obliquely from left to right. The arteria innominata is placed much more superficially than the left subclavian, being re- moved from the upper end of the sternum only the thickness of the transverse vein, and is very accessi- ble, as proved by Dr. Mott's operation; whereas the other, being the last branch given off from the curve of the aorta in its course backwards, is an inch deeper and inaccessible in the living body. The arteria in- nominata varies much in length before its division 188 OF THE TRUNK into subclavian and carotid; I have examples of n from half an inch to two inches, but the general length is about sixteen lines. In this dissection the phrenic nerve is seen to de- scend in contact with the internal edge of the scale- nus anticus muscle, and passing between the subcla- vian artery and vein to proceed vertically in contact with the pleura at first, and afterwards between it and the pericardium to the diaphragm. The par vagum is on the inner or mesial side of the internal jugular vein, and gets into the thorax between the subclavian artery and vein, near the origin of the subclavian ar- tery. The trunk of it passes along the side of the trachea, and behind the root of the lungs to the oeso- phagus and terminates at the stomach. On a level with the subclavian artery, the Recurrent or Inferior Laryngeal Nerve is sent off, which, to get to the larynx, winds around the subclavian of the right, and the aorta of the left side. About the root of the lungs, the Pulmonary Plexus is detached from the Par Va- gum nerve. The sympathetic nerve lies closer to the vertebra, and sends off from its two inferior cervical ganglions principally, the branches which supply the heart, by the cardiac plexus. In the thorax it conti- nues its course by the heads of the ribs, and sending off the greater and lesser Splanchnic nerves, is distri- buted in a manner to be described hereafter. In making this dissection it must be observed that, from the lower part of the thyroid gland, the condens-= VISCERA OF THE THORAX. 189 ed membrane or fascia is extended to the upper edge of the sternum, which seems to afford protection to the opening in the thorax, and beneath it, connecting the vessels and other parts together, is a loose, vas- cular, adipose, and cellular matter, which must be re- moved by dissection before the rest of the structure can be rendered distinct. The plan for opening the thorax, by the sternum being sawed in two longitudi- nally and kept open to the distance of an inch or so, is by far the most exact and satisfactory manner of studying these parts. This stage of the dissection having been accom- plished, the sternum must be removed, and by turn- ing up one side of the lungs, we see what is meant by posterior mediastinum and the parts contained in it. To the left is the aorta, which gradually gets to the front of the dorsal vertebrae in the lower part of the thorax, as it penetrates the crura of the dia- phragm. The (Esophagus is in the middle above, but in getting to its own opening in the diaphragm it crosses the aorta very obliquely and is then to the left of the lower dorsal vertebrae. The Vena Azygos, made up of the six lower intercostal veins on the left side and the ten lower of the right, occupies the right side of the mediastinum and forms an arch in its ter- mination where it joins the descending cava, over the right root of the lung. The Thoracic duct enters the thorax between the crura of the diaphragm, and passes nearly in the middle line between the aorta i90 OF THE TRUNK. and the vena azygos, till it reaches the third dorsal vertebra; it then inclines to the left side, and rising into the root of the neck, forms an arch which termi- nates in the angle formed by the junction of the left internal jugular and subclavian veins. The Par Va- gum is strictly within the limits of the posterior me- diastinum, the sympathetic is not. / PART II. CHAPTER II. Of the Abdomen. Before the commencement of the dissection of the Abdomen, it is useful to acquire a knowledge of its regions, the boundaries of which are thus esta- blished by imaginary planes passing through the sub- ject. Draw a line from the superior part of one Ileum as it appears through the skin, to the superior part of the other; strike a perpendicular then from the anterior superior spinous process of the Ileum on each side through the cartilages of the ribs above; then draw a fourth line parallel with the first through the points where the latter touch the cartilages. These four lines, two vertical and two horizontal, which re- present as many planes, form with the periphery of the abdomen nine regions. The one above on the right, is the right Hypochondriac, that in the middle the Epigastric, and that to the left, the left Hypo- chondriac. The region which has the navel in its centre is the Umbilical, and on its sides are the right and the left Lumbar Regions. Below the umbilical 192 OF THE TRUNK. is the Hypogastric Region, and on the wings of the latter are the right and the left Iliac Regions. Some anatomists call the pit around the ensiform cartilage the Scrobiculus Cordis, and a small space just be- hind, and elevating itself about an inch above the pubis, the Regio Pubis. The boundaries of the latter are rather undefined, but the terms are in use Section I. OF THE MUSCLES OF THE ABDOMEN. To begin the dissection of the muscles of the ab- domen, a straight cut must be made through the skin from the end of the second bone of the sternum to the symphysis pubis; another is to cross this at its commencement above, extending obliquely towards the arm-pit, till it reaches the side of the chest. The second terminates there, and a third commences which has a sweep backwards, corresponding in its direction with the margin of the cartilages of the ribs and equidistant from it. The third cut by be- ing extended to the spine affords an opportunity of opening the integuments still further by a vertical cut over the spinous processes down to the small end of the sacrum. This manner of opening the iqtegu- MUSCLES OF THE ABDOMEN. 193 vnents of the side of the belly, describes in a great measure the outline of the external oblique muscle, makes it thoroughly accessible in the progress of the dissection, and enables one to see and to display every part of it. One of the greatest obstacles (sim- ple as the circumstance may appear,) to understand- ing the broad muscles of the abdomen well, is the imperfect manner in which the integuments are open- ed by dissectors, and there is no dissection more often spoiled, than the very one in which we are now engag- ed, owing to the want of a plan (founded on some previous knowledge of the parts,) for commencing operations. Having thus marked off the section of the subject on which to work, begin by dissecting at the upper part of the flap to turn it downwards. But few strokes of the knife will be made before the fibres of the external oblique muscle at its upper part will be exposed. The flap is now to be entirely dissect- ed off as far down as the hip and thigh, exposing, by such means, the superior margin of the pelvis from the spine to the symphysis pubis. The beginner must cut very slowly on the muscular fibre, seeing that he detaches it fully from the cellular membrane, by cut- ting in the same direction with it; he will leave it clean and brilliant, and the transition from it to the broad tendon connected with it, will be comparatively easy. In this dissection, as indeed in all other muscular ones, I cannot attach too much importance to cutting in the course of the fibre; it is absolutely essential to Bb 194 OF THE TRUNK. the beauty of the display, and indispensable to a per- son desirous of doing well in his practical anatomy. A dissection done in any other manner is unfit for study from its obscurity, and offensive to inspect from its roughness. If I were under the necessity of sum- ming up directions to make a good muscular dissec- tor, I would say, always cut in the direction of the fibres, close to them, and keep the cellular membrane tense. There are five pair of muscles to the abdomen, three broad and two narrow. 1. Musculus Obliquus Externus, arises from the eight inferior ribs by muscular and fleshy digita- tions attached to their anterior extremities. The first head is covered by a slip from the pectoralis major, - the five upper heads are interlocked with the serratus major anticus, and the three inferior with the latissi- mus dorsi. The fibres pass obliquely downwards, and terminate in a broad thin tendon. This tendon extends over the whole front of the abdomen from the lower end of the second bone of the sternum to the symphysis of the pubis. Inserted into the whole length of the linea alba, and into the anterior half or two-thirds of crista of the Ileum, by muscular fibres posteriorly, and tendi- nous anteriorly. From the anterior superior spinous process, the tendon extends to the body of the pubis, forming the ligament of Poupart. MUSCLES OF THE ABDOMEN. 195 In the middle line of the body, the tendons of the three broad muscles on each side of the abdomen unite to form the Linea Alba, which extends from the sternum to the pubis. From two to three inches in the adult on each side of the linea alba, but more dis- tant from it above than below, is another line formed by a similar union of the same tendons, which is the Linea Semilunaris. The navel, which originally was a hole for the passage of the umbilical vessels, and which, in the adult, is commonly depressed into a pit, now appears as a protuberance in the linea alba com- posed of condensed cellular membrane. Just at the navel there appears a line crossing the linea alba, and extending from one linea semilunaris to the other. At the lower end of the Cartilago Ensiformis, there is another, and half-way between this and the navel, a third. About half-way between the navel and the pubis is a fourth, but it is generally imperfect. These are the Lineae Transversae, and they are form- ed by tendinous matter in the substance of the recti muscles, connecting them with their tendinous thecae in front. The most curious insertion of the tendon of the external oblique is, that part which is connected with the formation of Poupart's ligament. The latter, as it approaches the pubis from the Ileum, splits so as to leave a hole for the passage of the Spermatic Chord in the male, and of the Round Ligament of the Uterus in the female. This opening obtains the name 196 OF THE TRUNK. of Abdominal Ring. The tendon forming its upper boundary, is inserted into the symphysis pubis, and into the pubis of the opposite side, by fibres which are interwoven with and decussate those of its fellow. The tendon forming the lower margin of the ring, is inserted into the spine of the pubis, and into its crest for an inch. The portion inserted into the crest of the pubis, is Gimbernat's ligament, which, it will be readily understood, means only a part of Pou- part's. The ring in the External Oblique is rather trian- gular than round; its base is formed by the body of the pubis, and its point is at the place where the ten- don separates. The latter is kept from parting still further, by a fasciculus of tendinous fibres which runs across it. The sides of this opening are called its Columns, and from their situation, internal and exter- nal, or upper and lower Columns. There are several small round holes in the tendon of this muscle, which afford passage to nerves and to veins. When, by the cleanness of the dissection, the tendon has its characteristic gloss and polish, they are very distinct. Use. This muscle compresses the abdomen, and brings the pubis and thorax towards each other. The External Oblique is now to be turned over to the other side, by dissecting up its origin from the ribs, and its insertion into the crista of the Ileum. This process will enable the student to gain a more satis- MUSCLES OF THE ABDOMEN. 197 factory view of its insertion into the spine and crista of the pubis. 2. The Obliquus Internus lies beneath the last, and its fibres pass in a contrary direction to the fibres of the other. It arises tendinous, by the fascia lum- borum, from the three inferior spinous processes of the loins, and from all those of the sacrum, tendinous and fleshy, from the whole length of the crista of the Ileum, and fleshy from the upper half of Poupart's ligament. Though the fibres of this muscle, in gene- ral, are said to decussate the fibres of the external oblique, it must not be understood as applying to all of them, for the lower gradually are brought to pur- sue the same direction towards the symphysis of the pubis. Near the Linea Semilunaris, the muscular fibres cease, and the tendon begins. Inserted into the cartilaginous margin formed by the six inferior ribs; by tendons resembling condensed cellular membrane, into the cartilages of the seventh, eighth, and ninth ribs, and by flesh into the tenth, eleventh, and twelfth. It is inserted also into the side of the ensiform cartilage, its whole length, and into the linea alba from the sternum to the pubis. The tendon of this muscle divides into two laminae, in a manner which will be better explained presently, after the rectus and pyramidalis muscles have been dissected and turned down 198 OF THE TRUNK. Its use is the same as that of the External Oblique. The Internal Oblique is now to be dissected up from its attachments to the ribs, vertebrae, ileum, and external part of Poupart's ligament, beginning near the spine of the ileum, where it is separated more distinctly from the muscle below, by an artery, a vein, and cellular substance. 3. The Transversalis Abdominis, arises by the Fascia Lumborum, from the transverse processes of the last dorsal, and of the four upper lumbar ver- tebrae, and from the back part of the spine of the Ileum; fleshy from the anterior two-thirds of the spine of the Ileum, and from the exterior half of Pou- part's ligament; tendinous and fleshy alternately, from the inferior margin of the thorax formed by the car- tilages of the six or seven inferior ribs, at their inner surfaces, where they are concerned in the origin of the diaphragm. The fleshy part of this muscle occupies about one- third of its extent. It is inserted, above, into the sides of the ensiform cartilage, filling up the vacancy be- tween it and the cartilages of the sixth and seventh ribs, and into the linea alba, from the extremity of the sternum to the pubis, observing the arrangement of the tendon of the internal oblique, in a manner which will be presently mentioned. Use, to compress the contents of the abdomen. MUSCLES OF THE ABDOMEN. 199 4. The Rectus Abdominis muscle is seen beneath the tendons of the other muscles on each side of the linea alba. A longitudinal cut, its whole length, is to be made on its inner edge through these tendons, and they turned over towards the linea semilunaris. Its origin will then be seen as a flat tendon of an inch or more in breadth from the symphysis pubis and the upper posterior part of the body of the pubis. The muscle increases gradually to the breadth of three inches in its ascent. The tendinous intersections, confining it to the tendinous sheath in front, are es- tablished at the places mentioned as lineae transversa?, but, for the most part, they do not extend through the muscle. Inserted, fleshy, into the cartilago ensiformis and into the cartilages of the fifth, sixth and seventh ribs. It draws the thorax towards the abdomen. 5. The Pyramidalis is at the lower front part of the rectus. It arises somewhat thick, tendinous, and fleshy from the upper part of the pubis, from near its spine to the symphysis, between the rectus behind and the insertion of the external oblique before. It is fixed in a sheath formed by the separation of the tendons of the broad muscles. It tapers to a point above, and is Inserted into the linea alba and internal edge of the rectus, half-way between the umbilicus and the pubis. 200 OF THE TRUNK. It strengthens the lower part of the abdomen.* The Rectus and the Pyramidalis muscles are now to be detached from their origins and turned aside. By doing so we become sensible of an ar- rangement of the tendons of the broad muscles always difficult to describe, and generally imperfectly under- stood. It is this; at the linea semilunaris the tendons of the in ■ rnal oblique and transversalis unite inti- mately, and just beyond this junction two laminae are formed, which enclose the rectus muscle. The an- terior lamina is one-half of the tendon of the internal oblique, which, after passing half an inch or an inch, is joined to the tendon of the external oblique, goes in front of the rectus muscle, and covers it from ori- gin to insertion. The posterior lamina, made by the posterior half of the tendon of the internal oblique, is united already at the linea semilunaris to the tendon of the transversalis; in this manner they pass behind the rectus muscle from the cartilago ensiformis to a line half-way between the umbilicus and the pubis. From this line downwards, all the tendons go in front of the rectus muscle. The obliquus externus tendon may, however, be dissected from the common tendon of the others, without much difficulty, almost to the linea alba. The term insertion is very inadequate to express the manner in which the tendons of these broad mus- * This muscle is often wanting. MUSCLES OF THE ABDOMEN. £01 cles all terminate in the linea alba from the thorax to the pelvis, but the inspection of the part will now qualify the term so as to prevent mistakes. The Cremaster muscle is commonly attributed exclusively to the internal oblique, as it is said to be a detachment of fibres from it. The dissection is now in a stage to exhibit what is really the fact in regard to this muscle,—that it is also formed by fibres from the lower edge of the transversalis muscle. The history of its formation is as follows: in the descent of the testicle, the testicle has to pass beneath that edge of the transversalis and of the internal oblique which is extended from the upper part of Poupart's ligament to the spine of the pubis. As it descends it comes in contact with a fascicelus of these fibres and takes it along. This constitutes the Cremaster mus- cle, which, in adult life and in a strong muscular sub- ject, is seen descending on the outside of the sperma- tic chord, and spreading over the anterior part of the tunica vaginalis in arches with their convexities down- wards, then rising on the inner side of the chord and inserted into the spine of the pubis.* It draws up the testicle. As one becomes acquainted with the dissection of * Mr. J. Cloquet of Paris has given this explanation of the formation of the cremaster; it is, however, not in accord with Mr. Hunter's account of it. C C 202 OF THE TRUNK. this part by operating on a number of subjects, he will be sensible that there are differences in subjects which render many established descriptions occasion- ally erroneous. One of the most usual is the defici- ency of the transverse muscle in that part, the origin of which is usually attributed to the external portion of Poupart's ligament. In this case the internal ob- lique has increased thickness, and, of course, the cre- master will be exclusively derived from it. In other instances the two muscles are so much blended that they cannot be satisfactorily separated from each other. The Transversalis and the Internal Oblique per- form so important a part in the doctrines of Hernia that one desirous of understanding them well should, at this time, pay attention again to the mode of their insertion into the pubis. It will thus be seen that they form below a common tendon, which is inserted, for an inch, into the crista of the pubis behind Gim- bernafs ligament, into its spine, and into that part of its body which is behind the annulus abdominalis; and that just within and above their insertion the same common tendon splits into two laminae, one going be- fore and the other behind the pyramidalis muscle, thus forming a sheath for it. In examining the origins of the Recti muscles from behind, the peritoneum being stripped off, it will be seen that a protusion of intestine between them is prevented by the internal edge of the one tendon INGUINAL HERNIA. 203 overlapping the internal edge of the other, and by a triangular ligament called, by Mr. Breschet its disco- verer, the Superior Pubic Ligament. Section II. ON the parts concerned in inguinal hernia. It is better for the student to postpone the subject of Hernia until he has become acquainted with the abdominal muscles and the contents of the abdomen. When he has paid due attention to what is remarked concerning them, the rest of the investigation will be comparatively easy. Make an incision through the skin and fat, from the Umbilicus to the dorsum of the Penis; commence another at right angles with this, and continue it from the umbilicus in a straight line towards either flank; make a third incision parallel with the first, begin- ning an inch behind the anterior superior spinous process of the ilium, and terminating in the second incision. The flap thus marked out, must be turned down over the thigh by a careful dissection, which will expose fully the tendon of the External Oblique and Poupart's Ligament. In dissecting at the Abdo- minal Ring? do not work too closely between the sper- 204 OF THE TRUNK. matic cord and the margin of the ring; by which pre- caution we avoid cutting a fascia that unites the two. This fascia arises from the margin of the ring all round; it passes immediately to the spermatic cord, and is lost insensibly on the exterior surface of the cremaster muscle. A quantity of loose cellular sub- stance, intermixed with fat, is placed between the constituent parts of the cord and the cremaster mus- cle. This cellular substance, the cremaster muscle, and the fascia, form, in scrotal ruptures, a thick la- mina over the hernial sac, called Tunica Vaginalis Communis. Next make an incision through the tendon of the external oblique, commencing at the Linea Semiluna- ris, a quarter of an inch above the upper margin of the ring, and ending a quarter of an inch above the anterior superior spinous process of the Ilium. This incision should be regularly curved, its convexity be- ing downwards, and almost touching the middle of Poupart's ligament. The tendon of the external ob- lique, bordering on the incision, should be then turn- ed upwards and downwards, by which a good view is given of the inferior part of the internal oblique mus- cle where it arises from the iliac or upper half of Pou- part's ligament, and is inserted into the crista of the pubis just behind the external abdominal ring. The origin of the cremaster muscle^is- well seen, and the INGUINAL HERNIA. 205 constituent parts of the cord, as it is about to enter into the external ring. Separate the inferior margin of the internal oblique from Poupart's ligament, and turn it upwards, be- ginning near the anterior spine of the ilium, where the distinction between the internal oblique and the transversalis is better expressed. The lower part of the transversalis is thus exhibited placed behind the internal oblique, and having the same origin from Poupart's ligament and insertion into the Crista of the Pubis. The raising of the internal oblique brings into view more of the spermatic cord near the external ring. The Transversalis Muscle is then to be detached from Poupart's ligament, and raised up. This gives a complete view of the spermatic cord, consisting here, of its vessels, nerves, and excretory duct, united by cellular membrane. The upper part of the visible portion of the chord is about half way between the anterior spine of the ilium and the symphysis of the pubis, and penetrates the fascia transversalis. The fascia transversalis is placed immediately behind the transversus muscle, between it and the peritoneum. The opening of the fascia transversalis, which per- mits the cord to pass, is called the Internal Abdomi- nal Ring, in order to distinguish it from the opening in the tendon of the external oblique, called now the 206 OF THE TRUNK. External Ring. The internal ring is rather nearer to the symphysis pubis than to the spine of the ilium. It will now be understood that the space between the internal ring and the external ring, is about eighteen lines in the adult, and that it is very properly called the Abdominal Canal, as giving passage to the sper- matic cord. The anterior side of the canal is formed by the tendon of the external oblique; the inferior part in the erect posture, is formed by Gimbernat's ligament; the posterior parietes are formed by the fas- cia transversalis, and above this canal is overhung by the internal oblique and transversalis muscles. It should be observed that the spermatic cord, after pe- netrating the fascia transversalis, does not cross, di- rectly, the inferior edge of the internal oblique and transversalis muscle at right angles; but it crosses them very obliquely, its inclination being towards the pubis, so that the spermatic cord can only be consi- dered as disengaged from the inferior edge of these muscles, about the middle of the abdominal canal. The opening in the Fascia Transversalis is not abrupt and well defined; but the fascia, where it transmits the spermatic cord, is reflected by a thin process to the cord, and insensibly terminates on its cellular substance. At the posterior or ventral face of the External Ring, the fascia transversalis is not in contact with the cord, but that part of the tendon of the internal oblique and transversalis which is in- INGUINAL HERNIA. 207 serted into the crista of the pubis, and forms a sheath for the pyramidalis muscle, is placed between them, and secures this opening. » The incisions which were originally made through thejskin of the abdomen only, are now to be carried through the parietes of the abdomen into its cavity, and the flap thus constituted, to be turned down in order to get a view of its posterior or ventral face. This surface covered by peritoneum is divided in the iliac region near the middle of Pouparts ligament into two superficial fossae by a narrow falciform process of the peritoneum. The process arises from the side of the bladder and extends upwards and inwards to- wards the umbilicus, stopping about two inches short of the umbilicus. It is broader below than it is above, and its loose edge is turned towards the abdomen. By stripping down the peritoneum we shall see that this falciform process is simply a duplicature of it, occasioned by a fibrous cord, the umbilical ligament of the bladder, which once was the umbilical artery of the foetus. The cord passes near the pubic mar- gin of the internal abdominal ring. Replacing the peritoneum we become convinced that the bottom of the superficial fossa on the outer or iliac side of the falciform process, corresponds with the internal ab- dominal ring, and frequently a little pouch of perito- neum enters the internal ring. The fossa on the in- ner or pubic side of the falciform process is just be- 208 OF THE TRUNK. hind the external ring, but separated from it by the fascia transversalis and the tendons of the lower parts of the internal oblique and the transversalis muscles where they are inserted into the pubis, and form the sheath of the pyramidalis. The two fossae indicate the points where inguinal herniae commence, the proper inguinal profusion beginning in the exter- nal fossa, and the ventro-inguinal in the internal fossa. We should here notice the looseness of the attach- ment of the peritoneum by cellular substance to the parietes of the abdomen, and consequently the little resistance which it, unsupported, can afford against intestinal protusion. The view of the Fascia Transversalis from be- hind, is extremely satisfactory. For a knowledge of this membrane the profession is indebted to the la- bours of Sir Astley Cooper, and much of the zeal with which the anatomy of hernia has in latter years been investigated, is attributable to him. The fascia transversalis is a thin tendinous membrane most generally, occasionally it resembles more condensed cellular membrane. It arises from the internal or abdominal edge of Poupart's ligament, and from the crista of the pubes just behind the insertion of the tendon of the internal oblique and transversalis mus- cles, and is extended upwards on the posterior face of the transversalis muscle towards the thorax. At its origin it is attached to the inferior edge of the INGUINAL HERNIA. 209 tfansversalis and internal oblique, particularly the part of the edge between the internal ring and the pubis. It is also attached to the exterior margin of the rectus abdominis. The internal ring or opening in this fas- cia marks it out in some measure as consisting of two portions, that on the iliac side of the ring is not so thick as the other, or the one on its pubic side, and both portions are much more tendinous near the cru- ral arch than they are higher up. Removing the peritoneum from the iliacus internus muscle, we see the spermatic vessels descending from the loins to the internal ring, where they are joined by the vas deferens coming from the pelvis. As they engage under the edge of the internal oblique mus- cle, after penetrating the ring, the cremaster muscle is detached to spread itself over them. The sperma- tic cord, thus constructed, passes through the abdo- minal canal in the manner mentioned, obliquely down- wards and inwards; emerging from the external ring it descends vertically, lying rather upon the outer column of the ring than upon its base. On the posterior face of the fascia transversalis, between it and the peritoneum, is the Epigastric Ar- tery. The epigastric arises from the external iliac as the latter is about to go under the crural arch; it ascends inwardly along the internal margin of the in- ternal abdominal ring to the exterior margin of the d d ^10 OF THE TRUNK. rectus abdominis muscle, which it reaches after a course of two and a half or three inches. The sper- matic cord, in getting from the abdomen to the ab- dominal canal, therefore, winds, in part, around the epigastric artery, in the first of its course being at the iliac edge of the artery and then in front of it. Two epigastric veins attend the artery, one on each side, which end by a common trunk in the external iliac vein. From what has been said it will now be more fully understood that this structure admits of two places of protusion. In the first the intestine protudes the pe- ritoneum through the internal ring and along the ab- dominal canal into the groin, the constituent parts of the cord being below the sac and separated from the cremaster muscle, which, in this case, forms one of the envelopes of the sac. In the second, from weakness of the fascia transversalis and the pubic in- sertion of the internal oblique and transversalis mus- cles, a protusion may occur immediately from behind the external ring in which the whole cord, including the cremaster, is at the outer margin of the sac and does not cover the latter. In the first species, or the Inguinal, the epigastric artery is at the pubic side of the neck of the sac; but in the second, or the Ventro- inguinal, it is at the iliac side of the neck of the sac. The anatomical arrangement of the parts concern- FEMORAL HERNIA. 211 ed in inguinal hernia in the female is the same as in the male, except that the round ligament of the uterus supplies the place of spermatic cord. Section III. OF the parts concerned in femoral hernia. The study of Femoral Hernia should be commenc- ed with precise ideas of the concave edge of the os in- nominatum, terminated externally by the anterior su- perior spinous process of the ilium, and internally by the symphysis pubis—also of the muscles of the lower extremity which are connected with this edge,—and of the insertion of the tendon of the external oblique. A muscular subject without much fat answers suf- ficiently well for this dissection; the male black is, therefore, most frequently resorted to in our school. If the subject have suffered somewhat from a previ- ous infiltration or dropsy of the cellular membrane, the facility of separating the different layers of fascia from each other is much increased. Make an inci- sion through the skin from the umbilicus to the root of the penis, and extend the lower end of the incision around the penis along the internal margin of the thigh for six inches. Commence a second incision 212 OF THE TRUNK. at the umbilicus, and carry it out to the flank of the side on which you operate. Begin a third incision through the skin at the termination of the first and carry it to the outer side of the thigh. A flap, con- sisting simply of skin, being thus described, is to be carefully raised and turned out of the way. In raising this flap of skin'guard against cutting up with it the fascia superficialis which lies immediately beneath. This fascia consists of condensed cellular membrane, which may be considered as taking its ori- gin on the front of the thigh, and extending, in front of the abdominal muscles, as high up as the thorax; indeed, if we are disposed to trace it to its whole ex- tent, there is no difficulty in following it over the front of the thorax also, to the neck and even to the face. In ordinary cases its aponeurotic, character is very equivocal, but where the parts on the thigh have been pressed upon and thickened by the irritation of hernial protusion it is better expressed. On the thigh it is blended with fat, and encloses between its laminae the lymphatic glands of the groin, and the small ves- sels given off from the femoral artery immediately below Poupart's ligament. On the tendon of the ex- ternal oblique it is more condensed; branches of the femoral artery are also seen in it there; one longer and larger than the others, winds over Poupart's li- gament and runs upwards somewhat in the line of the epigastric artery, being distributed to the skin of the abdomen. It may properly enough be called FEMORAL HERNIA. 213 the External Epigastric Artery, as the division of it wi4f produce sufficient hemorrhage to require atten- tion. On the symphysis pubis and about the ex- ternal ring the laminae of the fascia superficialis are multiplied, and it has more of the character of com mon adipose matter, as in all cases the adeps there is abundant. This fascia is more loosely connected to the parts beneath it, along the anterior margin of Poupart's ligament than elsewhere, which disposes the femoral hernia to observe that course in its in- crease. From the pubis it may be traced along the penis as a condensed cellular membrane to its extre- mity, and, according to Mr. Colles of Dublin, when matter is formed beneath it, it is apt to create fistu- lous sores on this organ. A thin edge of this mem brane may be traced for some distance reflected along the spermatic cord. The Fascia Superficialis, under the name of Tu nica Abdominalis, is well developed in animals with a large and projecting belly, particularly in the large ruminantia and the solipedia. It has a yellowish tinge, is very elastic and strong, and well calculated to sup- port the viscera in them. The Fascia Femoris is beneath the fascia super- ficialis; its general character and arrangement is in- troduced into the account of the lower extremity, but there are other and minute circumstances in its dis- 214 OF THE TRUNK. position at the groin, indispensable to a knowledge of femoral hernia. When the fascia superficial^ is cleared away, the fascia femoris is seen to arise from the anterior edge of Poupart's ligament, from the spine of the ilium to within a short distance of the spine of the pubis. This portion of it is thin, and through it the sartorius muscle may be seen. The fascia arises also from the crest of the pubis, and from the ileo pectineal ridge of the pubis, which is a con- tinuation of the same; this latter portion covers the pectineus muscle. Hence the one is called the sarto- rial, and the other the pectineal fascia. The pectineal fascia is behind the femoral artery and vein, and the sartorial fascia is before them. The Saphena Vein, placed between the fascia femoris and the fascia superficialis, runs up along the inner side of the thigh, and joins the femoral vein an inch and a half below Poupart's ligament. Raise the saphena where it joins the femoral vein, and be- neath this junction a rounded semicircular edge of the fascia femoris is seen, where the sartorial fascia becomes continuous with the pectineal. Apply the end of a finger to this edge and draw it downwards. Immediately on its being made tense, the sartorial fascia will show itself to terminate by a thin edge in front of the femoral vein. This edge is concave or crescentic, and extends from the junction of the sar- torial and pectineal fascia to near the crista of the FEMORAL HERNIA. 215 pubis. At the upper end of this crescent, the sarto- rial fascia terminates in a point or angle which is turned, inwards towards the pubis. The upper mar- gin of the angle is closely connected with Gimber- nat's ligament near its edge, and the point is inserted jnto the pectineal fascia over the crista of the pubis and for a line or two below it, just at the internal margin of the femoral vein, or rather about half-way between it and the spine of the pubis. This angular production or elongation of the sartorial fascia is called Hey's or the Femoral Ligament. By introducing a finger under Hey's ligament into the abdomen, we find that the crural arch or Poupart's ligament, and the sartorial fascia exercise a mutual tension on each other like the falx major and the ten- torium; by abducting the limb very much and turning the toe outwards, the greatest rigidity is given to both, but by making the limb cross the other and turning the toe inwards, both are relaxed. A posterior view must now be taken by opening the abdomen. The peritoneum must be separated from the abdominal muscles and from the iliacus in- ternus and psoas magnus, which brings into view the fascia iliaca. The Fascia Iliaca is a tendinous membrane which lies on the iliacus internus and psoas magnus, and 216 OF THE TRUNK. is continued into the tendon of the Psoas Parvus. Externally it is connected to the margin of the crista of the ilium, at the internal edge of the psoas mag- nus it is connected with the brim of the pelvis and sinks into the cavity of the pelvis, being continu- ous with the Aponeurosis Pelvica, and below it is in- serted into the edge of the crural arch from the an- terior superior spinous process of the ilium almost to the pubis. The external iliac vessels are upon this fascia between it and the peritoneum; by raising them with a knife-handle it will be seen that the fascia iliaca goes over that part of the pubis which gives origin to the pectineus muscle, and that it is continuous with the pectineal fascia. If the student should have a prepa- ration in which every thing is removed from the os in- nominatum except the insertion of the tendon of the external oblique, it will be of essential service to him here: for by it will be seen the arched form of the edge of the tendon next to the bone, from whence the name Crural Arch; the vacancy which exists be- tween the bone and the arch; and the insertion of Gimbernat's ligament from the spine of the pubis, an inch or more along its crista. He will then under- stand how this space is only partly filled by the iliacus internus and psoas magnus, and that if the fascia iliaca had not an attachment to the crural arch so as to keep it down towards these muscles, hernial profu- sions would be constantly occurring. FEMORAL HERNIA. 217 The iliac vessels pass beneath the crural arch on the inner margin of the psoas magnus muscle, the vein being nearest the pubis and the artery at the outer side of the vein. Close inspection will satisfy us that the fascia iliaca is inserted into the crural arch as far as the vein, and may indeed bp traced to the crista of the pubis, and that it is so connected with the vessels that no opening for hernia exists between them, nor indeed in all the space from the internal margin of the vein to the spine of the ilium. But at the inner side of the vein between it and Gimber- nat's ligament an opening appears called the Crural Ring, and is the place where femoral hernia com- mences. This opening is generally occupied by a lym- phatic gland and a lamina of condensed but loosely attached cellular substance continuous with the Apo- neurosis Pelvica. Make a cross cut of an inch in length, through the Fascia Iliaca; then, by introducing the finger, or a knife-handle through this cut, downwards, our con- ceptions of the attachment of the fascia iliaca with the crural arch, and its continuity with the fascia pec- tinea, will be much improved. The femoral vessels are enveloped by a sheath. In order to see this distinctly, separate the fascia trans- versalis from the transverse muscle; cut vertically through the falciform process of the fascia lata, over e e 218 OF THE TRUNK the artery, and continue the cut also through Pou- part's Ligament, taking care to injure the fascia trans- versalis as little as possible. In order to render this part of the examination convenient, only a narrow flap of the abdominal muscles should be left at the groin. By turning towards the symphysis pubis, the falciform process, with that part of Poupart's liga- ment to which it adheres, we shall see that the fascia transversalis is not only attached to the edge of the crural arch, but that it continues to the thigh in front of the femoral vessels. The fascia iliaca, besides its connection with the pectineal fascia, gives a layer to the posterior face of the femoral vessels. The crural sheath is then formed from the fascia transversalis in front, and the fascia iliaca behind. Mr. Colles has adopted a very satisfactory mode of describing the formation of the crural sheath, which I think more expressive than such as are most in use. The fascia transversalis and iliaca, he considers as a continuous membrane, which may be compared to a funnel, from the manner in which it lines the lower part of the abdomen. The inner side of the funnel is deficient. From its lower part proceeds the membranous neck which surrounds the femoral vessels, and constitutes their sheath. This sheath is very separable from the fascia lata in front, and the pectineal fascia behind, and may be traced, easily, to the entrance of the sa- phena vein into the femoral. On the thigh, just be- low Poupart's ligament, it has a number of foramina FEMORAL HERNIA. glfi *n it occasioned by the passage of the lymphatic ves- sels from the surface of the thigh. At the place where the fascia iliaca is united to the crural arch, a white line appears, formed by their union; in this is fixed the Arteria Circumflexa Ilii, coming from the external iliac. The epigastric ar- tery is about half an inch distant from the Femoral or Crural Ring, at its outer side. Occasionally, the Obturator Artery comes from the Epigastric, and winds around the internal margin of the ring. As the iliac vessels enter the sheath beneath Poupart's li- gament, a close connection is formed by the reflection of a membrane from them to the sheath, both ante- riorly and posteriorly, which membrane sends a par- tition between the artery and the vein, and a partition also on the inner side of the vein. By such arrange- ment, hernial profusions are prevented at this spot; the only opening for them, being at the inner side of the vein between it and Gimbernat's ligament, or at the CruraLRing, as stated. When an intestine descends, it passes into the fe- moral sheath on the inner side of the iliac vein, it fol- lows the course of this vein down the sheath, till it comes to an aperture made by one of the lymphatic vessels; it then protrudes through this aperture, and gets under the fascia superficialis. Afterwards, if the hernia increase, instead of continuing to descend, it 220 OF THE TRUNK. turns upwards and outwards, towards the anterior spine of the ilium. From this, it is obvious, that the places of stricture may be: First, the opening in the femoral sheath for the lymphatic: Secondly, Hey's Ligament; and Thirdly, the edge of Gimbernat's li- gament which looks towards the iliac vein. Mr. Colles, whose opinions are entitled to the utmost re- spect, thinks that surgeons err in regard to the third place, and that the stricture is formed there, by the internal margin of the commencement of the femoral sheath instead of Gimbernat's ligament. He says that this orifice remains with a sharp and distinct edge, even when Gimbernat's ligament is taken completely out of the way, and that the edge of Gimbernat's li- gament, supposed to constitute this stricture, stops se- veral lines short of the Crural Ring. A dissection performed in the manner that he recommends, is un- questionably in favour of his position. The Anterior Crural Nerve has but little to do with this dissection, as it is placed beneath the fascia iliaca, and is on the outside of the artery. CONTENTS OF THE ABDOMEN. 221 Section IV. OF THE CONTENTS OF THE ABDOMEN. For common examination, a crucial incision through the parietes of the Abdomen, from the ster- num to the pubis, on the left of the navel, and from one side to the other, on a line with the umbilicus, but a little below it, answers very well. The flaps, thus made, being turned aside, and kept down, the viscera of the abdomen can be easily seen. 1. The Liver is in the Right Hypochondriac region; it occupies nearly the whole of it; the upper part of the Epigastric, and the right superior part of the left Hypochondriac. The fundus of the gall-bladder pro- jects from its right inferior surface beyond its ante- rior edge. 2. The Stomach, when not distended much, is confined to the Epigastric region below, and to the right inferior part of the left Hypochondriac. 3. The Spleen, if not large, recedes into the back part of the left Hypochondriac so much, that to be seen it must be drawn out. 222 OF THE TRUNK. 4. The small Intestines lie in the Umbilical, Hypo- gastric, part of the Iliac regions, and also in the Pel- vis, when the viscera of the latter are not distended. 5. The Colon begins in the right Iliac region, passes up into the right Lumbar and Hypochondriac, and through the upper part of the Umbilical, or the lower of the Epigastric, according to the distention of the stomach; it then gets to the left Hypochondriac, being commonly higher up in it than in the right Hy- pochondriac; thence it passes into the left Lumbar and Iliac, forms its sigmoid flexure, and dips into the pelvis, where it is continuous with the rectum. 6. In front of the small intestines, is the Omentum, most frequently found gathered up in the Umbilical region. If it be not diseased, it may be drawn down- wards to the pelvis, and spread out so as to conceal all the front of the intestines. 7. At the back of the Epigastric Region, behind the stomach, is the Pancreas; it lies horizontally, and ex- tends from the right of the spine into the left Hypo- chondriac. It cannot be seen without cutting through the omentum, and turning the stomach upwards. 8. In the Lumbar Regions, at their back parts, are the Kidneys and Capsula Renales. They should not be sought for at this stage of the dissection. CONTENTS OF THE ABDOMEN. 223 It is useful to know that the position of the viscera of the abdomen is influenced much by the position of the body, and that what is said of the occupancy of the regions, is from a consideration of the subject be- ing on his back. When one stands upright, the lum- bar vertebrae are more convex in front, and the abdo- men more protuberant below. The pelvis is so adjusted that the acetabula are nearly in a vertical line with the spine, which gives great obliquity to the superior strait, mounts the sacrum up on high, and brings the bodies and rami of the pubis not many degrees from the horizontal line. All of the viscera descend, but more particularly the liver, which being no longer sustained by the false ribs, and being in- fluenced by its heavy inert mass, may, in many cases, be felt externally along the margin of the ribs. This descent of the liver will be according to the degree of vacuity of the stomach, intestines, and bladder. It is said by Winslow, that the uneasiness, pain, and faintness we feel in a vacuity of the stomach, &c. from the want of food, arise from the liver drawing the diaphragm downwards. Portal informs us, that in order to ascertain the descent of the liver in the erect posture, he has often thrust poignards below the false ribs of dead bodies, and that he has invariably found the wounds much higher up than when they were inflicted in the horizontal posture. It should be well recollected that the abdominal cavity is always full, there being no unoccupied space 224 OF THE TRUNK. in it; hence, whenever any viscus has an inordinate growth, or a tumour forms on it, or an effusion occurs in the peritoneal cavity, the other viscera are en- croached upon. In a treatment for sickness, when the stomach and bowels have been evacuated by low diet and purging, air supplies the place of more solid matter, and keeps them distended. It is indeed ex- ceedingly rare to find the small intestines contracted; in the large, it is more common. Having become generally informed on the viscera of the abdomen, by repeated handling, we should, in the next place, proceed to an examination of their forms and structure. The Peritoneum is a thin, delicate, semitranspa- rent membrane, very extensible, and spread out so as to line the cavity of the abdomen, and to give an external covering to the greater number of its viscera. In man, it is a complete sac, having no hole in it; but in woman, its cavity communicates externally through the fallopian tubes. It has a double use; in consequence of covering the viscera, it is so re- flected from them to the sides of the abdomen, that its processes keep the viscera in their proper places, and are therefore called Ligaments. Again, its in- ternal surface being smooth, and indeed highly po- lished, and continually lubricated by a thin albumi- nous fluid corresponding with the synovial membrane of the joints, the motions which the viscera have upon CONTENTS OF THE ABDOMEN. 225 each other in exercise, and in the peristaltic move* ments of the bowels, are much facilitated. The manner in which a double night-cap is applied to the head, will afford the most simple conception of the reflections of the peritoneum. If there were only one viscus in the belly, and that of a somewhat regu- lar outline, as the liver, the comparison would be rigid, and perfectly appreciable. One part of the cap is close to the head, and compares with the peritoneal coat of the liver; the other is loose, and is equivalent to the peritoneum, which is in contact with the pa- rietes of the belly. It is also evident from this, how none of the viscera can be said to be within the ca- vity of the peritoneum; that they are all on its out- side, and that a viscus, in getting a coat from the pe- ritoneum, merely makes a protusion into its cavity. Starting with this most simple part of the proposition, it is easy to conceive of a second, a third body, and so on, deriving an external coat from a protusion into the same sac. Admitting these bodies to be spheres, the conception of the proposition is immediate; and as a last step from this, the idea is not rendered much more complex by substituting any bodies, even the most irregular in form, for these spheres. Such, then, is the fact, in regard to the stomach, intestines, &c.; they all, except the kidneys, derive an external coat from the peritoneum. The reflections of peritoneum forming the liga- ments of the liver will be best described in connec- Ff 226 OF THE TRUNK. tion with that viscus. Its reflections over the viscera of the pelvis will be described with them; we will merely say for the present that it covers the upper and back part of the urinary bladder, and is reflected from it to the rectum. The reflections for immediate study are the Omen- tums, Fatty Appendages of the Colon, and the Me- senteries. 1. There are four Omentums. Omentum Minus or Hepatico Gastricum, Omentum Majus or Gastro- Colicum, Omentum Gastro-Splenicum, Omentum Colicum. a. The Omentum Minus extends in a transverse direction from the transverse fissure of the liver where the capsule of Ghsson is connected, from the left of the lobulus spigelii, and from the inferior face of the diaphragm to the lesser curvature of the stomach be- tween the end of the oesophagus and the pylorus and duodenum. It is composed of two laminae which, near the stomach, are separated by the coronary ves- sels. It has always but an inconsiderable quantity of fat in it. b. The Omentum Majus, or Gastro-Colicum, is an irregular quadrilateral membrane having its base upwards. The latter is fixed anteriorly to the greater curvature of the stomach, and posteriorly to the trans- CONTENTS OF THE ABDOMEN. 221 verse arch of the colon. It hangs loose in its infe- rior part, and is sometimes found spread over the in- testines as low as the pelvis; it is, therefore, not im- properly compared to an apron. On its right side it is continued into the omentum colicum, and on the left into the gastro-splenicum; It consists of two la- minae, the anterior is fixed to the stomach, the poste- rior to the colon. Each of these laminae again is composed of two, so that it may be compared to two bags, one within the other, connected at their upper or open end to the stomach and colon. The inter- nal and external bags are very separable above, but below they are closely united. In corpulent subjects a great deal of fat is found in this membrane. c. The Omentum Colicum is a prolongation of peritoneum from the internal side of the caecum and right ascending colon, and from the inferior part of the transverse colon. It is sometimes seen to extend itself as far as the spleen under the omentum gastro- colicum. It is also filled with fat from the same causes as the preceding, but consists of only two sin- gle laminae somewhat separated by the colic arteries and veins. d. The Omentum Gastro-Splenicum is that pro- cess of peritoneum which extends from the large ex- tremity of the stomach to the spleen; it may be con- sidered a prolongation of the omentum majus, and en- 228 OF THE TRUNK. closes in its duplicature the arteries and veins called Vasa Brevia. e. The Appendicul^e Epiploic^: are little pro- cesses of peritoneum, filled with fat, appended at ir- regular intervals to the anterior sides of the caecum, colon, and the upper part of the rectum. By searching for the neck of the gall-bladder we shall find near it, under the capsule of Glisson, the Foramen of Winslow, an opening which conducts into the bag of the omentum majus. It is large enough to admit two fingers easily. By detaching the omentum majus from the stomach, and turning it down, we shall see the nature of its cavity, its extent, and all the parts constituting its parietes. This ca- vity is bounded above, by the omentum minus and stomach; below, and in front, by the two laminae sent from the stomach; behind, and below, by these laminae being reflected upwards and joining the co- lon, and posteriorly and above by the upper lamina of the mesocolon which is extended to the lobulus spigelii. By a little reflection it will be understood that I have described an uninterrupted cavity, be- ginning at the lobulus spigelii by the omentum mi- nus, and terminating with the lobulus spigelii by the upper lamina of the mesocolon. It is acknowledged on all sides to be one of the most difficult propositions in descriptive anatomy, even when the subject is be- fore a young student. It is a point well worth mas- CONTENTS OF THE ABDOMEN. 229 tering, as, when this is well done, all other embarrass- ments, in studying the reflections of the peritoneum, are much ameliorated. The Mesenterium is extended obliquely across the spine from a line parallel with the second lumbar vertebra to the right iliac fossa. This part, called its root, in the adult, is about six inches in length and flat, but the inferior edge, which is loose and pendu- lous having the intestines connected with it, has its circumference increased to many feet, which causes it to lie in folds. The mesentery attaches the left ex- tremity of the duodenum, the jejunum, and ileum to the spine. It consists of two laminae of peritoneum separated by the mesenteric arteries and veins, the lacteal glands and vessels, and the nerves derived from the solar plexus. There is also some fat between them. The Mesocolon fixes the large intestines to the back of the abdomen. The posterior part of the caecum is devoid of peritoneal coat, and is of course in contact with the internal iliac muscle where it is tied down. The colon in the right and left lumbar regions is also for the most part immoveably fixed, the mesocolon being there of very little length, but the transverse colon is long, and forms a complete and moveable portion between the upper and the lower parts of the abdomen, which permits the colon to ascend and descend according to the distention of th<» 230 OF THE TRUNK. small bowels and stomach. In the left iliac region the mesocolon is elongated so much as to allow very free motion to the sigmoid flexure of the gut, and con- tinues into the meso-rectum. of the ventriculus, or stomach. The Stomach is a sac curved considerably. As was stated, it is in the epigastric region, in con- tact above with the diaphragm, the left lobe of the liver and the lobulus spigelii, on the left with the spleen, on the right with the duodenum and pancreas, and below with the colon and mesocolon. The sto- mach has a very great obliquity in its situation, the right extremity being much lower down than the left. The exterior of the stomach presents two faces, two curvatures, two orifices, and one tuberosity. When the stomach is nearly empty it becomes some- what flattened, and then exhibits an anterior and a posterior face; in a state of distention, the first looks obliquely upwards, and the latter obliquely down- wards. The angle, formed with the oesophagus, is increased according to the degree of distention. The orifices are the Pyloric and the Cardiac. The pyloric viewed externally presents nothing remarkable but seems to be a continuation of the right extremity of the stomach into the duodenum. The cardiac, formed by the junction of the oesophagus with it, is at the upper edge of the stomach about one-third of the length of the organ from its extreme left. CONTENTS OF THE ABDOMEN. 231 The curvatures are the Great and Small. The first includes the great extremity and the inferior edge of the stomach to the pylorus; the smaller is the upper margin between the orifices. The Tuber or great extremity of the stomach is the part to the left of a vertical plane passing through the cardia; it is smaller in proportion in children than in adults. The stomach consists of four laminae. The ex- ternal is peritoneal, and derived from the separation of the two leaves of the omentum minus. The second is muscular, its thickness is inconsiderable, and the fibres which compose it are remarkably pale. They are best seen near the cardia and at the pylo- rus. At the latter they are collected into a ring of considerable thickness, which produces a marked prominence internally, constituting the valve of the pylorus. The muscular fibres go in three directions. The first longitudinal, and continued from similar ones of the oesophagus, extend to the pyloric orifice. The principal part of them is collected into two bands, the thicker of which passes along the lesser curvature, and the thinner along the greater. The second set of muscular fibres surrounds the stomach by segments of circles, none of them going completely around. It is this set which forms the pyloric valve. The third set of muscular fibres is oblique, and has been indicated by Gavard, as form- ing two large bands. One is extended from the left 2S2 OF THE TRUNK. side of the cardia over the anterior and posterior faces of the stomach, and the other is prolonged from the right side of the same orifice over the great ex- tremity, where it supplies the want of transverse or circular fibres. The third coat of the stomach consists of a very dense compact short cellular membrane, which unites the muscular and internal coat, and conducts the vessels and nerves to the latter.- The fourth, or Internal Coat of the stomach, some- times called the Mucous or Villous, is of a light red. It is formed of villosities like velvet, which terminate at the cardiac orifice; it is thrown into very irregular folds, according to the degree of dilatation of the sto- mach, and by its reflection over the circular plane of fibres at the pylorus increases the projection of the valve. OF THE INTESTINAL CANAL. This Canal is from thirty to thirty-five feet long, in the human subject, and extends from the Pylorus to the Anus. It consists of two portions, the longer forming four-fifths of the whole, extends from the stomach to the ileo-caecal valve, the other from this latter to the anus. The first is Intestinum Tenue, the second Intestinum Crassum. This canal consists of four coats, peritoneal, muscular, nervous, and vil- lous. CONTENTS OF THE ABDOMEN. 233 The small Intestine, or Intestinum Tenue, is di- vided, somewhat unnaturally, into three parts, by ana- tomists, Duodenum, Jejunum, and Ileum. The first, from peculiar circumstances, is perhaps named pro- perly enough; but several distinguished men, as Chaus- sier, Soemmering, &c. think that the two last may be treated of more advantageously, under the name of Mesenteric Portion of Small Intestine. The Duodenum deduces its name from its length, which has been fixed at twelve fingers breadth. It is also called Ventriculus Succenturiatus. Beginning at the pylorus, it passes to the right, and upwards, to- wards the neck of the gall-bladder; it then forms a right angle, and passes downwards before the right kidney, to the third lumbar vertebra behind the superior la- mina of the transverse mesocolon. Here it forms a round elbow, and crosses the spine obliquely upwards, making its appearance to the left of the second lum- bar vertebra, where it is continued into the mesen- teric portion of intestine. The head of the Pancreas lies in the bend of the duodenum, and fixes it firmly just there. The first part, where it emanates from the pylorus, is moveable, and covered with peritoneum; the second and third portions are between the laminae of the mesocolon, but have no peritoneal coat; and the fourth portion is both moveable, and has a peritoneal coat. The partial deficiency of peritoneal coat, is said to be the 6 g 234 01 THE TRUNK. cause why the duodenum is susceptible of an enlarge ment, in some cases, but little inferior to the stomach. The muscular coat of this intestine consists of two planes of fibres, the external one longitudinal, the other circular and much the most numerous. Be- neath is the coat of cellular membrane connecting it with the mucous or villous coat. The internal coat is reddish, tinged with bile, and occupied by a great num- ber of rugae or folds. They are transverse and ob- lique, very near each other, about three lines broad, and as prominent in the distended as the undistend- ed gut; these constitute the Valvulae Conniventes. Many mucous follicles exist in this intestine, and mu- cous glands, called Glandulae Brunneri; the latter are particularly accumulated about the pyloric orifice. It is, in its posterior part, about four inches from the stomach, that the orifices of the pancreatic and he- patic ducts are found. The Inferior, or Mesenteric portion of the Intesti- num Tenue, has the same coats with the preceding. In the upper two-fifths, called Jejunum, the valvulae conniventes are numerous, and arranged transversely; but in the lower three-fifths, called Ileum, they gra- dually diminish, and near its termination, cease en- tirely. There is a gradual diminution of the diame- ter of this intestine from above downwards. From the length of the mesentery, great latitude of motion is allowed to it. It presents a very irregular and con- fusing appearance at first, but one soon becomes ac- CONTENTS OF THE ABDOMEN. 235 customed to its course and convolutions; and then its commencement and termination are as readily found as those of any other organ. It is probable that in the distentions of this bowel, the peritoneal coat does not stretch much, as the laminae of mesentery are loosely applied against each other where they join the intes- tine, and are separated in its distentions, as far as the first row of the mesenteric arches of blood-vessels. Cases are reported, in which it has had appendicu- lae epiploicae and cul-de-sacs projecting from its sides. I have never seen the former, but of the lattef, a spe- cimen was presented to me a few years ago, taken from a child by the late Dr. Edward Barton; and another specimen now belongs to the Wistar Mu- seum, obtained the last winter in the dissecting rooms. The mucous or nervous coat of the Intestinum Te- nue, differs from that of the stomach, in resembling more the downy cuticle of an unripe peach. The little projections from it, are called Villi; on the sur- faces of which, open the orifices of the lacteals. It abounds with mucous follicles and glands; the latter, called Gland ulae Peyeri, are particularly conspicuous near its junction with the mesentery. The large Intestine, or the Intestinum Crassum, has already been explained in regard to its course. It is more obviously a conical tube than the small in- testine, being very large at its commencement when inflated, and diminishing much before it terminates. 236 OF THE TRUNK. Anatomists call its commencement, or that part be- low the ileo-colic valve Caecum, or Caput Coli; and the remaining portion, which is by far the longest, the Co- lon, until it reaches the pelvis, when it becomes Rec- tum. The Caput Coli is about two inches in length, and is fixed to the iliac fossa by peritoneum and loose cellular membrane. At its inferior extremity, on the left side, is the Appendix Vermiformis, a blind cavity of four coats, about four inches long, and of the size of a turkey quill, enclosed in a duplicature of perito- neum. It floats loose, and occasionally becomes a cause of mischief, by getting around the ileum, and inflaming, by which it adheres and produces, in some measure, strangulation. The Colon makes a large sweep around the abdomen, and in passing under the gall-bladder, touches it, and thus becomes tinged with bile after death. In its transverse course, we fre- quently find it passing through the umbilical region. The coats of the Intestinum Crassum, correspond in number with those of the small intestine; but there are some differences in structure. The longitudinal muscular fibres are much more conspicuous; they are collected into three bands, which commence at the head of the colon, and extend to the upper part of the rectum; one is superior, another inferior, and a third anterior. They are equidistant from each other. These longitudinal bands produce the cells of the co- lon, by drawing its extremities nearer together. The CONTENTS OF THE ABDOMEN. 237 cells are separated laterally, by partitions or but- tresses formed of a doubling of all the coats of the in- testine; whereas in the small intestine, the valve or doubling belongs exclusively to the mucous mem- brane. These cells are not so numerous or well formed in the sigmoid flexure and thereabouts; the channel is therefore more open and unobstructed. By dividing the longitudinal bands, the cells are re- moved, and the intestine elongates considerably. The Ileo Colic Valve, or valve of Bauhen, or Tul- pius, is a great curiosity in the anatomical structure of this gut. The ileum runs into the left side of the colon, and continues its cellular and mucous coat into the corresponding coats of the colon, the muscular coat of the latter being simply parted. To prevent the further separation of the muscular fibres, a little transverse ligamentous arrangement prevails at each end, called Retinacula Morgagni. When viewed from within the colon, the opening appears as a transverse or very narrow elliptical slit, established by two lips, the superior smaller, that is, narrower than the infe- rior. They meet like the gates of the common ship dock or hydraulic lock; and from being placed trans- versely, in regard to the cavity of the intestine, every distention which the latter may suffer from accumu- lation of faeces, having a tendency to force this valve, will, by stretching its extremities, make the lips tighter and more resisting. The internal coat of the large intestine differs verv 238 OF THE TRUNK. materially from that of the small. It has no villi. Near its commencement, it preserves the fungous ap- pearance of the stomach, but about the sigmoid flex- ure, it is a plain smooth surface, having a great many mucous follicles and mucous glands in it. It has lac- teals, but they are not so numerous. The Rectum will be described with the Pelvis. OF THE LIVER, (HEPAR SIVE IECUR.) Its position in the abdomen and the space it occu- pies have been mentioned. It is placed in the follow- ing relations: above, it is in contact with the conca- vity of the diaphragm; below, are the Omentum Mi- nus, the Stomach, and the Transverse Arch of the Colon; behind, are the Vertebral Column and the As- cending Cava. When we lie on the right side it is sustained by the ribs in the easiest posture; when on the left it sometimes occasions uneasiness by press- ing on the stomach; and when on the back it com- presses the ascending cava. Its form is happily compared, by Professor Chaus- sier, to the section of an ovoid made in the direction of its greatest diameter, the thick end being to the right? side. It is fastened in its situation by the fol- lowing reflections of the peritoneum. From the cen- tre of the diaphragm, and extending from the umbi- licus backwards to near the ascending cava, is the Falciform or Suspensory Ligament, consisting of two CONTENTS OF THE ABDOMEN. 239 laminae; it is thickened at its anterior edge by what was once umbilical vein in the foetus, but is now con- verted into a fibrous substance called Round Liga- ment. This falciform ligament divides the upper surface of the liver unequally into two, the left being the smaller; it also penetrates a notch in the anterior edge of the liver. On the right of the falciform pro- cess, and extending from the diaphragm to the poste- rior edge of the liver, is the Right Lateral Ligament; to the left of the same process, and also extending from the diaphragm to the back edge of the liver, is the Left Lateral Ligament; and that portion of peri- toneum concerned in the union of these three liga- ments forms the Coronary Ligament. Within the circumference of the coronary ligament the surface of the liver is not covered by peritoneum, and it is at- tached to the diaphragm by loose cellular substance. The precise shape of the liver is best seen in one removed from the body. Its colour is a reddish brown. The following parts are noticed by anato- mists: its upper surface, its lower surface, its right extremity, its left extremity, its anterior edge, and its posterior edge. The upper surface is uniformly convex, and pre- sents nothing remarkable but its unequal division by the falciform ligament. The lower surface is very irregularly concave, and on it are to be remarked the following appearances: From the front to the back edge is a deep fissure cor- 240 OF THE TRUNK. responding, in situation, with the suspensory ligament above, and, with it, giving occasion to divide the liver into right and left lobes. This is the Sulcus Umbi- licalis, formed in front by what was umbilical vein, and in the rear by what was ductus venosus, both vessels in the adult being in a ligamentous state. Crossing this fissure at right angles, passing from the right to the left lobe, and occupying about the middle third of the long diameter of the liver, is the Sulcus Transversalis. In it are the Vena Portarum, Hepa- tic Artery, and Ducts. The Lobulus Spigelii or pos- terior lobe is at the back of the livCr just to the left of the posterior part of the sulcus umbilicalis. It is like a ridge, and terminates forwards in a papillae which is one of the portae of the liver; to the right, the lobulus spigelii sends off a small process which unites it with the greater lobe of the liver, and is call- ed the Lobulus Caudatus. On the front of the infe- rior surface between the fore part of the umbilical fissure and the gall-bladder is a flat rising, the Lobu lus Anonymus or Quadratus; its posterior extremity, opposite to the anterior of the lobulus spigelii, is the second pula or porta of the liver. The right extremity of the liver is very thick and almost fills the right hypochondriac region, but the left tapers to a verv thin edge. The posterior border or edge is thick, but the anterior is thin. The former is marked by a short large sulcus for the descending vena cava, sometimes converted into a complete canal; CONTENTS OF THE ABDOMEN. 241 the latter only has the notch for the suspensory liga- ment already mentioned. Besides the peritoneal coat, the liver has a second, which covers its whole exterior surface, adhering very closely to the peritoneum on one stde, and to the liver on the other; it penetrates into the substance of the liver, and holds together its granulated structure* This tunic is easily seen by stripping off the perito- neum, and in parts which naturally are left uncover- ed by the latter. The Blood-vessels are of three kinds. The two first bring the blood to the liver, the third takes it away. The hepatic artery, a branch of the coeliac, after having detached some smaller ramifications, gets to the transverse fissure of the liver and divides into three branches; one to the right lobe, one to the left lobe, and another to the Lobulus Spigelii; they, how- ever, subdivide before they reach the substance of the liver. These branches are between the vena porta- rum and the biliary duct. The vena portarum is formed from the union of all the veins of the intes- tines, stomach, pancreas, and spleen, forming a single trunk about three inches long. It gets to the trans- verse fissure of the liver, over the duodenum and under the pancreas, and immediately sends off, at right angles, two branches which, collectively, are * See Soemmering's Anatomy. Laennec's Journal de Me- decine. Hh 24,2 OF THE TRUNK, called the sinus of the vena portarum. The right branch, being the shortest and largest, is distributed to the great right lobe; the left sends its branches to the lobulus spigelii, anonymus, and left lobe. At the bottom of the transverse fissure is a lamel- lated fibrous cellular tissue, closely adhering to the liver, which accompanies the vena portarum, the he- patic artery, and hepatic duct in their ramifications, forming sheaths for them as they go off successively. As the branches of these tubes keep together they are united by the cellular sheaths. Glisson believed these sheaths to be muscular, and they have obtained the name of his capsule; and, indeed, the capsule is generally spoken of as lying on the aforementioned ves- sels, even before they reach the liver. The hepatic veins arise from the capillary extremities of the hepa- tic artery and vena portarum; there are three princi- pal trunks of them coming, two from the right and one from the left lobe of the liver, and emptying into the ascending cava just below the diaphragm; there are also, occasionally, five or six little trunks, coming from the eminences on the inferior surface of the liver, which empty into the ascending cava below the others. The hepatic veins have no valves, and may, in a section of the liver, be readily distinguished from other vessels by their lonely course, by their crossing the others at right angles, and by their thin- ness. All of these vessels of the liver are remark- able by the number of their anastomoses and the CONTENTS OF THE ABDOMEN. 24$ facility of their communication with each other. A minute injection of either shows all parts of the liver as pervaded, and a continuation of the injection will fill all the other vessels. By tearing the substance of the liver a good view of its organization may be ob- tained; it will then be seen to be composed of an im- mense number of spherical or polyhedral grains united to each other by the cellular tissue of the in- ternal coat. These grains contain the essential and ultimate points of the glandular arrangement, the anas- tomoses of the vessels are formed in them, and also the capillaries of the hepatic duct; but what the final organization is by which bile is formed no one has told. The nerves of the Liver will be mentioned at ano- ther place, along with the general account of such as belong to the Abdomen. The Gall-bladder, (Vesicula sive Cistis Fellea,) is fixed on the inferior surface of the great lobe, in a broad shallow fossa for the purpose. It is not placed in the line of the short diameter of the liver, but ob- liquely, its anterior end, which reaches to the edge of the liver, being turned to the right, and its posterior, which goes to the transverse fissure, being turned to- wards the left. Its shape is conical, the base being rounded off and the apex curved; the body diminishes gradually to the apex. The gall-bladder has three coats; the peritoneal is only partial, from the upper face of the gall-bladder being in contact with the liver. The second coat is cellular membrane, in which 244 OF THE TRUNK. ramifies a great number of blood-vessels and lympha- tics. The third may be considered a continuation of the mucous coat of the intestines, but has some pecu- liarities. On its internal face, it is thrown into irre- gular tortuous folds or wrinkles of extreme delicacy, in the intervals of which are many round or polyhe- dral cells; some small, others a line and a half deep, particularly about the middle of the body. In the neck or apex of the gall-bladder, from three to seven elevated semilunar folds are formed, of the internal membrane. The gall-bladder and the contiguous parts, after death, are always tinged with bile, which does not oc- cur in the living body. I have, however, in one case in our dissecting rooms, seen a gall-bladder in an old African woman, filled by a pint of very fluid watery greenish bile, and the tissue of which had been so lax, that a quart or more of the same secretion had exuded into the abdomen probably before death. The Hepatic Duct arises, by very delicate branches, from the granuli of the Liver. These branches are united into three or four trunks, in the transverse fissure, which trunks again unite into one about the size of a writing quill, and eighteen or twenty lines long. The Hepatic Duct joins, at a very acute angle, with the Cystic Duct, which is somewhat smaller and shorter, and the two form the Ductus Communis Choledochus. The biliary canals thus CONTENTS OF THE ABDOMEN. 245 formed, are situated in the right side of the Hepato- gastric, or lesser Omentum, in what is commonly call- ed Capsule of Glisson. The Ductus Communis be- ing three inches, or three and a half long, is to the right of the Vena Portarum and the Hepatic artery, descends behind the pancreas and the upper part of the duodenum, and passes obliquely between the coats of this intestine, for the distance of an inch, its orifice being, as mentioned, at the back of the second turn of the intestine. The Biliary ducts have two coats. The external is a lamellated fibrous membrane, highly extensible, and having many blood-vessels. The internal is of the same character with that of the gall-bladder. In the cystic canal, and towards the lower part of the Ductus Communis, are several longitudinal folds. OF THE SPLEEN, (LIEN. SPLEN.) This organ, as mentioned, is situated deeply in the left hypochondriac region, in the concavity of the Dia- phragm, at the left extremity of the stomach, and above the Colon. Its form approaches to the longitu- dinal section of an oval, being commonly four and a half inches long, and two and a half wide. But there is no viscus in which more frequent varieties of magni- tude occur. I have seen it extending almost to the Ilium, and but little smaller than the liver; and again, not by any means the length just expressed as a medium 246 OF THE TRUNK. size. Its transitions of magnitude are frequent and rapid in the same individual, depending on the stage of digestion, upon sickness, and probably on mental sensations. Several spleens sometimes exist in the same person. In such cases the supernumerary ones are, for the most part, very small. The Spleen has a partial division lengthwise, by a fossa, where the blood-vessels are connected with it Its circumference is generally notched. Its colour varies from a deep blue, which it is in early life, to a very dark brown. It is fixed by three processes of pe- ritoneum, the names of which indicate their attach- ments; the Gastro-splenic, the Splenico-phrenic, and the Splenico-colic ligaments. The external coat of the spleen is obtained from the peritoneum, being a continuation of the ligaments just mentioned. The internal coat is a greyish, thick, extensible, elastic membrane, in close adherence with the external; at the longitudinal fissure, it sends in processes to accompany the blood-vessels. It seems to be intended to sustain the natural shape of the spleen, and to support its parenchymatous structure. The spleen is remarkably well furnished with blood- vessels. It derives a large artery from the coeliac, distinguished by its tortuous course, by the branches which it furnishes to the stomach and to the pancreas. It divides into several trunks just before it enters the spleen. The veins come out by an equal number of trunks, unite into one trunk, and attend the artery CONTENTS OF THE ABDOMEN. 247 along the upper edge of the pancreas; it joins the Vena Portarum. In the body of the spleen are found many greyish, soft, semitransparent gelatinous corpuscles, from an almost imperceptible magnitude to that of a pin's head. By Malpighi, they were considered glandular; and by Ruysh, as convoluted vessels. The mass of the spleen, upon a superficial examination, seems to consist in a bloody dark brown pulp, contained in numerous cells resembling the structure of a sponge. (See Wistar Museum, Case 13.) On this cellular structure, the vessels pass. M. Assolont considers that blood forms the basis of the peculiar organization of the spleen; that, besides existing in the arteries and veins, it is placed in a state of particular combination, and of in- timate union with the other organic elements of the viscus, and with a large quantity of albumen; that this peculiar combination of the blood forms the dark grumous fluid just mentioned, which may be easily seen by scraping the spleen with the handle of a scal- pel. Of the latter, there can be no doubt; but a ques- tion arises whether it is contained in the cells I have just spoken of, or in the extremities of the vessels. Slight examination is in favour of the former, butM. Marjolin denies it, on the following grounds: That injections, cautiously made, pass immediately from its arteries into the veins; and that when the spleen, successfully injected, is frozen, one can see no ice in the interstices of the vessels, while the capillary rami* 248 OF THE TRUNK fications of the vessels distended by the injected fluid, are distinctly seen. The probability then is, that the parenchymatous structure of the spleen is formed essentially, of arterial and venous capillary vessels, with very delicate and extensible coats, and that they communicate with each other, without the interme- dium of any cell; and that the extreme tenuity of these vessels, and their extensibility in every direction, are sufficient to explain the augmentation of volume which the spleen affords, under different circum- stances, and the promptitude with which it diminishes in the experiments made on it. OF THE PANCREAS, (PANCREAS.) This is an oblong conglomerate gland, fixed in the back and lower part of the epigastric region, extend- ing across the spine. It is connected to the spleen on the left, to the duodenum on the right, is behind the stomach and between the laminae of the transverse mesocolon. The Pancreas is of a light grey colour, being about seven inches long and two wide; it would represent tolerably a parallellogram if, at its right extremity, it were not swollen out into a head, to which WinsloW gave the name of Small Pancreas. It has two faces, two edges, and two extremities. The anterior face is turned obliquely upwards and corresponds with the superior lamina of the mesocolon. The posterior CONTENTS OF THE ABDOMEN. 249 face is obliquely downwards, has a long fossa in its upper part for the splenic vessels, and is in contact with the aorta, vena cava ascendens, the superior mesenteric vessels, and several nerves. The pancreas has no peritoneal coat, neither has it a proper tunic, unless one should consider as such the lamina of condensed cellular membrane which envelopes it, and which sends in processes between its lobules. The structure of the pancreas strongly resembles that of the salivary glands as it consists of granuli, united into lobules, which form lobes whose interstices are occupied with numerous vessels. The excretory duct of the gland arises by very fine radicules from these granulations, which, uniting, form larger cylin- ders inclining from left to right. These latter empty successively into a long tube going the whole length of the gland and situated near the very centre of its substance, (the Ductus Wirsungii;) it is small at the splenic extremity, but gradually increases till it be- comes as large as a crow's quill at the other end. It is there joined by the duct of the lesser pancreas, and in a short course afterwards empties into the ductus communis choledochus, or sometimes runs at its side and makes a distinct opening into the duodenum at the posterior part of its second curvature. The arteries of the pancreas are principally deriv- ed from the splenic. The veins empty into the sple- nic. i i 250 OF THE TRUNK. OF THE KIDNEYS, (RENES.) To get a good view of them, the other abdominal viscera should be removed, and at least the intestines. The Kidneys are two glandular bodies for the se- cretion of urine, fixed one on each side of the spine. They are in the back part of the lumbar regions in a space extending from the upper part of the eleventh dorsal vertebra to the lower part of the second lum- bar, though the right, in consequence of the pressure of the liver from above, is lower down than the left. They are deposited on the upper part of the great psoas and the quadrati lumborum muscles, and on the lower of the diaphragm in a large quantity of fat. The shape of the kidney is a compressed ovoid ex- cavated on one side like a bean, the broad end of the ovoid being above, and the excavation presenting ob- liquely forwards and inwards. The excavation has a deep fissure in it for the blood-vessels and excre- tory duct. The kidney is hard and solid; its colour is brown. The kidney has not a peritoneal coat, but it has a proper capsule, which completely envelopes it and pe- netrates deeply into its fissure, till it reaches its pel- vis; it is here perforated with many foramina for transmitting blood-vessels. This membrane is fibrous, semitransparent, and somewhat elastic; it is easily peeled from the surface of the kidney, and in doing CONTENTS OF THE ABDOMEN. 251 so we see that it adheres by a very delicate cellular and fibrous tissue and by some small vessels. The kidney being originally formed in lobes which subse- quently unite, the vestige of this union is frequently preserved. In regard to the structure of the kidney; it receives from ^the aorta, at right angles, a large artery, the Emulgent, which divides into several branches as it approaches the fissure; these terminate by penetrat- ing to all parts of the structure in a vast crowd of ar- terioles, so that when they are injected with wax and corroded, the figure of the gland is preserved Some of these minute arterial branches terminate in cor- responding veins, others in the parenchymatous struc- ture of the organ, and others on the branches of the excretory duct. The kidney being laid open longi- tudinally, we shall obtain an idea of its internal ar- rangement. It is seen obviously to consist of two parts of different appearance, the external which, from its position, is called Cortical, and the Internal or Tubular. The cortical part is the most vascular; it is, at an average, about two lines in depth, and forms the periphery of the gland, but different portions of it project and form partial partitions between the tu- bular sections. It tears with facility, with a some- what granulated edge or surface, and its colour is a dark or reddish brown. When viewed with a micro- scope the granulations are distinctly seen of extreme minuteness, and formed by the capillary extremities of 252 OF THE TRUNK! arteries and veins. 1 have more than once injected these granulations from the arteries, and observed the fluid coming through the ureters and the emulgent vein. The second or Tubular portion of the parenchy- matous organization of the kidneys, to the naked eye, consists of conoidal fasciculi of fibres presenting their bases to the periphery of the organ, and their apices towards its centre. These cones are from twelve to eighteen in number, being, as mentioned, partially se- parated from each other by processes from the corti- cal part; they are dense, of a lighter brown, and tear with facility in the course of the fibres. Each cone is formed by a great number of very fine converging canals, close to each other near the apex, and conti- nuous at the other end with the vessels of the cor- tical part. They appear only to give passage to the urine, as cases have occurred in which they were entirely removed by suppuration and ulceration. (See Wristar Museum, Case 12.) The technical name for these canals is Tubuli Uriniferi. The termina- tions of the cones are called Papillae, and an attempt has been made to establish for them some peculi- arity of organization; but that idea is now abandoned, and they are generally admitted to be the same with the other portions of the tubular part. They have many orifices in them which are the terminations of the tubes, and from which urine in most subjects can be readily squeezed. CONTENTS OF THE ABDOMEN. 253 Around the base of each papilla and adhering to it is a membrane also conoidal, the Infundibulum, or funnel-shape canal, for conducting the urine into a large cavity in the kidney called the Pelvis, which in fact is made up by the concurrence of the infundi- bula. There are about twelve infundibula, generally three of them discharge by their little ends into a common tube, and the union of three or four of these tubes, as the case may be, constitutes the pelvis of the kidney.' Sometimes two papillae have a common in- fundibulum; there are in truth many modifications in the collateral arrangement of the gland, which could not be introduced into an abbreviation like the pre- sent. The Ureter arises from the pelvis, and is the excretory duct. It is a continuation of the same membrane consisting of two coats, the external of which is fibrous and the internal mucous. The latter is said to be continued over the papillae, and may probably enter into the tubuli uriniferi. The Ureter is about the size of a writing quill, en- joys an exalted degree of extensibility and contractility of tissue, and its sensibility not perceptible in health, is exquisite in disease. It is in contact behind with the psoas magnus muscle and the iliac and hypogas- tric vessels, it crosses the vas deferens at the back part of the bladder, and passing obliquely through the coats of the latter, has its orifice a little behind that of the Urethra. 254 OF THE TRUNK. The emulgent veins are parallel with the arteries, ^ and terminate in the vena cava ascendens. OF THE RENAL CAPSULES, (CAPSULJE RENALES.) They are two little triangular pyramidal bodies, placed one upon each kidney at its superior part: they are of a yellowish brown colour somewhat tinged with red, and being connected with some process of foetal existence, are much larger there than- in the adult; their structure also seems to be much changed in the latter. From being placed precisely on the upper extremity of the kidney they have the lower surface which touches it of a corresponding conca- vity. On the exterior of this body is a proper eoat form- ed of lamellated and condensed cellular tissue, which furnishes from its internal surface many prolonga- tions, dividing the gland into lobes. These lobes are divisible into lobules, which again consist of a granu- lated structure that seems susceptible of other divi- sions. These granulations are not firm and resisting. In the centre of the Capsula Renalis is a triangu- lar cavity which may be readily demonstrated by thrusting a tube into it, and inflating, or by an inci- sion. The sides of this cavity are smooth, but below there is a small rising. In the foetus this cavity con- tains a reddish viscid fluid coagulable by alcohol: in children it becomes yellow: in adults it is dark brown; DIAPHRAGM. 255 and in old people it is either wanting or in a remark- ably small quantity. The arteries of these bodies come from the emul- gents, the phrenics and the aorta. The veins, termi- nate on the right side in the cava, and on the left in the emulgent. Section V. THE DIAPHRAGM, (DIAPHRAGMA,) Is a complete, though moveable septum, placed be- tween the thoracic and abdominal cavities; it is ex- tremely concave below and convex above, the con- cavity being occupied by several of the abdominal vis- cera. To view it properly, all the abdominal viscera should be removed, a large billet of wood placed under the loins of the subject, and the peritoneum carefully dissected off. It is particularly necessary to attend to the latter direction in order to get a good view of the various structure of this important or- gan, and the dissector, while performing it, is con- tinually liable to the accident of making a puncture through it into the thorax, in which case the dia- phragm loses its concavity, and becoming flabby and displaced, the value and beauty of the display are much impaired. 256 OF THE TRUNK. The dissection being properly achieved, exhibits a broad concave muscle connected with the inferior margin of the bony thorax on all sides, and having for its centre a silvery tendon resembling in its outline the heart of a playing card. This cordiform tendon occupies a considerable part of the extent of the dia- phragm, having its apex next to the sternum and its notch towards the spine; the muscular part of the diaphragm is inserted all around its circumference. The cordiform tendon is nearly horizontal in the erect posture, its elevation being on a line with the lowest end of the second bone of the sternum. On each side of this tendon the muscular fibres rise so high upwards before they join it, that they are on a horizontal level with the anterior end of the fourth rib. The fasciculi of muscular fibres are, for the most part, convergent from the circumference of the thorax, and are easily separated from each other. In the diaphragm are three remarkable foramina. The first is in the back of the muscle between the spine and the notch of the cordiform tendon, a little to the left. It gives passage to the oesophagus and the par vagum as connected with it, and is rather a fis- sure or a long elliptical foramen made by the separa- tion and reunion of the muscular fibres; for above and below at each end of the ellipsis these fibres decussate each other in columns. To the right of this foramen and a little above its horizontal level in the back part of the cordiform tendon, is a very large and patulous DIAPHRAGM. 251 foramen for the ascending vena cava. It is between an irregular quadrilateral figure and a circle; its edges are composed of fasciculi of tendon rounded off, and are not susceptible of displacement or of alteration in their relative position to each other, with a view of obviating any impediment which might arise from a different arrangement, to the course of the blood in the ascending cava. Almost in a vertical . line below, but about three inches from the foramen for the oesophagus, is the third hole in the diaphragm, which affords passage to the aorta. It is just in front of the bodies of the three upper lumbar vertebrae, and is a much longer elliptical hole than the oesopha- geal; its lowest extremity or pole is constituted by the tendinous crura of the diaphragm, and its upper by a decussation of muscular fasciculi arising from them. Through it, besides the aorta, pass the Thoracic Duct, and the Great Splanchnic Nerve from each side. In the horizontal position of either the dead or the living body, the right side of the diaphragm ascends higher in the thorax than the left, but the weight of the liver makes it descend lower than the other in the vertical posture. Thus circumstanced, the Diaphragm arises fleshy, from the internal face of the upper edge of the Xi- phoid Cartilage, from the internal face of the carti- lages of the seventh true, and of the succeeding false ribs, on each side. That is, from the cartilages of the k k 258 OF THE TRUNK. eighth and ninth, from the osseous extremities of the tenth and eleventh, and from both the osseous and cartilaginous termination of the twelfth rib. As the line described includes almost the whole of a circle, and the fibres all converge to the cordiform tendon, they, of course, will pass in different radiated directions and be of different lengths, which it is unnecessary to specify. Between the sternal and costal portions, on each side, there is a triangular fissure filled with fatty cellular tissue, which sometimes leaves an opening for Hernia. I have seen a case of this kind, in which the transverse part of the Colon was the subject of protrusion into the Thorax; and it is probable that the great displacement of abdominal viscera, found in the thorax of adults or children, may have had a conge- nital origin in this very fissure, which is subsequently, when the parts are modified to this unnatural situa- tion, set down as Lusus Naturae. The part describ- ed, is called the greater muscle of the Diaphragm. Besides these origins, the Diaphragm has several from the vertebrae of the loins, called its crura, there being four on each side of the foramen for the aorta. The first pair, entirely tendinous, comes from the front of the body of the third vertebra of the loins, and is pre- vented from being very distinct in its origin, in conse- quence of running into the ligament in front of the bodies of all the vertebrae. The second pair of heads is on the outside of the first, and arises tendinous from the Intervertebral ligament, between the second and DIAPHRAGM. 259 third vertebrae. The third pair of heads arises ten- dinous from the upper parts of the lateral margins of the second lumbar vertebra. And the fourth pair of heads comes also tendinous from the fore part of the root of the transverse process of the second lumbar vertebra. These tendinous heads terminate in what is called the Lesser muscle of the Diaphragm, which is inserted into the notch of the cordiform tendon. It will now be understood that the aorta passes be- tween the heads of the lesser muscle, and that the oesophagus has a hole in the upper part of its belly.* The origin of the Diaphragm is completed between its greater and lesser muscles, by a tense ligament, called Ligamentum Arcuatum, which passes from the root of the transverse process of the first lumbar ver- tebra to the inferior part of the middle of the twelfth rib; with the upper edge of this ligament the Dia- phragm is connected; and with the lower, the psoas magnus muscle. At the margin of the other ribs, this muscle is connected with the transversalis abdominis. The action of this muscle, in assisting respiration, is very obvious; its fibres passing in a curved line with their convexity, towards the thorax, from the bony margin of the thorax to the cordiform tendon, and * This origin of the lesser muscle of the Diaphragm is given by Albinus, but it is difficult to make out fairly, and for the most part it would be much better to say that it arises tendi- nous, from the first, second, and third vertebrae. The heads are occasionally much smaller on one side than the other. 260 OF THE TRUNK. having a tendency to become straight, by contracting will descend, and thereby enlarge the thorax. It is not certain that the cordiform tendon descends, its connections being too strong and numerous to admit of much motion. In expiration, the relaxation of the Diaphragm, with the contraction of the abdomi- nal muscles, restore the former to its first state. In vomitingf the Diaphragm and abdominal muscles con- cur to expel the contents of the stomach. PART II. CHAPTER III. Of the Male Pelvis. I have chosen to give this a distinct chapter, not only on account of its importance, but because the dissections which are performed on it have but little connection with the parts just described, are perform- ed in very different postures of the subject from the preceding, and have in them an intrinsic difficulty re- quiring them to be made in several ways in order to exhibit well the relative position and anatomy of the parts. I conceive that the first step of the student, after a short examination in situ of the contents of the pelvis, should be to detach the penis from its bony connections and to remove it, with the bladder and rectum, from the pelvis. Then to make a fair and clean dissection of these organs by detaching the sur- rounding fat, cellular membrane, and muscles. This dissection is best made with the scissors, and its uti- lity is in proportion to its cleanness; the latter is much assisted by inflating the bladder and by stuffing the 262 OF THE TRUNK. rectum. The scrotum may be separated and laid aside for future examination. Section 1. OF THE VISCERA OF THE MALE PELVIS. The Rectum, being the termination of the colon, has its origin at the left side of the fifth lumbar ver- tebra; from thence it passes down obliquely towards the middle of the sacrum about one-half of its length; its course afterwards is directly downwards before the sacrum and os coccygis till it terminates in the anus, its orifice there points backwards and downwards. When not distended by foecal matter its volume is always less considerable than that of the colon. It is cylindrical till just before its termination, it then di- lates into a pouch which is spread on each side of the prostate, and is apt to be cut in lithotomy. The inferior third of the rectum is destitute of pe- ritoneum, its anterior face is in contact with the lower fundus of the bladder, the vesiculae seminales, and the prostate gland. Posteriorly and above it is con- fined to the sacrum by the mesorectum, which con- ducts its nerves and blood-vessels. The dip of the peritoneum, between the vesiculae seminales so as al- MALE PELVIS. 263 most to touch the base of the prostate gland, should be remarked. The muscular structure of this gut is remarkably strong, consisting, externally, of vertical and parallel fasciculi of fibres close together, and internally of cir- cular fibres which form a thick and continued plane, particularly on a level with the lower fundus of the bladder. Just below the pouch of the rectum these circular fibres form the Internal Sphincter Muscle. The mucous membrane of the gut is smooth above, but at the lower part it is thrown into several longi- tudinal folds, called the Columns of the Rectum, con- nected together by transverse or oblique folds, the edges of which are inclined upwards and form little pockets. The villosities of this surface are distin- guishable, as well as its mucous lacunae which are numerous. The inferior orifice of the rectum is thrown into radiated folds from the influence of the sphincter ani. The Bladder, (Vesica Urinaria,) is fixed just be- hind the symphysis of the pubis, and from being pressed upon by the neighbouring viscera, when dis- tended, it is somewhat flattened before and behind; but removed from the body it resembles an elongated sphere, of which the greatest diameter is vertical in regard to the linea ileo pectinea. The technical name for each end of the sphere is Fundus, distin- guished by the terms upper and lower, the lower be- 264 OF THE TRUNK ing somewhat the more obtuse. From the upper end proceeds a long conical ligament, the Urachus, to the navel, and at the anterior part of the lower fundus, the bladder is somewhat elongated into a process, (re- sembling a truncated cone,) the commencement of the urethra, and called its Neck. By putting the ante- rior parietes of the abdomen on the stretch wre shall see starting out and protruding the peritoneum on each side of the urachus, the remains of the umbilical ar- teries of the foetus which now are called the Round Ligaments of the bladder, though they have but little or no influence on it. The bladder consists of four tunics; the Peritoneal, Muscular, Cellular, and Miacous. The Peritoneal is a very incomplete coat placed upon the upper and posterior parts of the bladder, and passing from it to the muscles of the abdomen before, and to the rectum behind. It is connected to the muscular coat by very loose cellular membrane, which prevents it from participating in very considerable distentions of the organ, and permits it to leave the anterior face of the bladder, so that its reflection to the recti muscles, in these cases, is placed much above the pubis. Tapping is performed here as well as the high operation for the stone. The Muscular coat consists of flattened fasciculi of white fibres passing in very irregular directions, MALE PELVIS. 265 and separated to some distance from each other. Many of them arise from the neck of the bladder and pass before and behind upwards towards the urachus, where they end; others, arising laterally from the same place, pass up in a corresponding course and also terminate at the urachus. There are many transverse and oblique fibres uniting these together, but still leaving interstices through which the internal coat occasionally protudes, and thus forms cells in the cavity of the bladder. There is an accumulation of these fibres about the neck of the bladder and the urachus, which gives it an increased thickness at these points. The Cellular coat consists of a close, dense, la- mellated, and fibrous tissue, highly extensible and dif- ficult to tear. It is impervious to water, closely ad- herent to the muscular and mucous membranes, and pervaded by many vessels. The Mucous; or internal coat of the bladder, though called villous, has less of this appearance than that of the stomach. It is white with a slight tinge of red; abounds with mucous follicles which, in a state of health, are difficult to be discerned; possesses great extensibility and but little contractility, from whence, when the bladder is not very full, it is thrown into folds passing in various directions. It offers several points for observation. 1. A triangular space be- l! 266 OF THE TRUNK. tween the orifice of the urethra and those of the ure- ters, (the Trigone Vesicale of the French,) which is bounded by elevated lines passing between these holes, and within is a plain smooth surface. Mr. Charles Bell thinks the lateral elevations are muscular and in- tended to regulate the orifices of the ureters. 2. The Uvula Vesicae, a small pointed production terminating the trigone in front, and formed by a projection of the third lobe of the prostate gland into the cavity of the bladder. 3. The orifices of the ureters, about an inch behind the orifice of the urethra and situated be- fore an oblong elevation of the mucous membrane. 4. The Inferior Fundus, (bas-fond of the French,) a depression of the general concavity of the bladder making it lower than any other part, placed between the base of the trigone and the posterior side of the bladder. 5. The Internal Orifice of the neck of the bladder, resembling somewhat a crescent, extending its horns around the uvula vesicae. The Neck of the Bladder is thicker than any other part; it is surrounded by cellular tissue in which a great number of veins is found, and it penetrates, in front, the prostate gland, which has a continual ten- dency to close it. The muscular fibres concurring in its formation have not been considered, by the greater number of anatomists, as sufficiently regular to form a distinct sphincter muscle, but Mr. Charles Bell differs from them and gives the following ac- count of it: " Begin the dissection by taking off the MALE PELVIS. 267 inner membrane of the bladder from around the ori- fice of the urethra. A set of fibres will be discovered on the lower harr of the orifice which, being carefully dissected, will be found to run in a semicircular form round the urethra. These fibres make a band of about half an inch in breadth, particularly strong on the lower part of the opening, and, having mounted a little above the orifice on each side, they disperse a portion of their fibres in the substance of the bladder. A. smaller and somewhat weaker set of fibres will be seen to complete their course, surrounding the orifice on the upper part; to these sphincter fibres a bridle is joined, which comes from the union of the mus- cles of the ureters." prostate gland, (glandula PARASTATA.) This is a body about the size and form of a horse chesnut, fixed on the neck of the bladder, and pene- trated by the urethra, which traverses it much nearer its superior than its inferior surface. The base of it is turned backwards, and the point forwards; its infe- rior surface rests upon the rectum, and its sides, in the distentions of this organ by faeces, are overlapped by it. The Prostate has, posteriorly, a notch in its cen- tre, which divides it into two lateral lobes, and by raising the Vesiculae Seminales, we shall see where their excretory ducts penetrate the gland, and sepa- rate from the body of it the little tubercle, to which Jb'tf OF THE TRUNK Sir Everard Home has particularly called the atten- tion of the profession, and considered as a Third Lobe, it being certain that it is frequently the seat of disease and tumefaction. (See Wistar Museum, Case \2.) The organization of this body seems to consist in a condensed white, extensible, though easily lacerat- ed cellular tissue, and within it are placed a great number of mucous follicles, which form from eight to twelve ducts, passing obliquely forwards, and ter- minating in the urethra on each side of the urethral crest or Caput Gallinaginis. The fluid secreted is thick, ropy, white,, and semitransparent in a healthy state. The Prostate is surrounded by a fibrous cap- sule, of which more hereafter.* The Seminal Vesicles, (Vesiculae Seminales,) are two convoluted bodies of two inches in length, one on each side of the lower fundus of the bladder, ap- proaching each other very nearly at the base of the Prostate, but diverging much as they recede. They are separated before, by the interposition of the vasa deferentia, and being fixed between the rectum and the bladder, they are matted to the latter by a close * An opinion prevails among the anatomists of Philadelphia that the prostate is larger in the African than in whites. In- deed this much may be said of all the organs of generation in both sexes, MALE PELVIS. 269 cellular membrane, having many large veins pervad- ing it. When inflated and dried, they present the sem- blance of cells, but are in fact long tubes, which, by being convoluted, are reduced to the apparent dimen- sions mentioned: there are also several pouches on each side of this long tube which increase the num- ber of cells. The convolutions are preserved by the intermediate cellular tissue. These bodies consist of two coats, an external, which is fibrous and cellular; and an internal, which is mucous, being a continua- tion of the lining membrane of the bladder. They are commonly filled by a drab-coloured thick fluid, supposed to be a mixture of the semen, and of their own proper secretion, though, of this, Mr. Hunter doubted.* The excretory ducts of these vesicles are about a line and a half long, when each joins in the substance of the prostate with the vas deferens of the same side; a common canal (Ductus Ejaculatorius) is thus formed, which runs parallel with its fellow, be- low the urethra. The Ductus Ejaculatorius, is about an inch long, and opens by an oblong orifice, at the lateral and anterior faces of the Caput Gallinaginis; it is larger behind than before, which gives it very much * See Observations on the Universal GLconomy. 270 OF THE TRUNK. of a conical shape, and allows fluids injected to pass freely from the vas deferens to the vesiculae, or vice versa. OF THE PENIS, (MEMBRUM VIRILE, MENTULA.) It is a membranous and vascular body affixed to the inferior margin of the pelvis, and appropriated to the excretion of urine and semen. It is formed by the common integuments, by cellular tissue, by the corpus cavernosum, and by the corpus spongiosum. The skin covering the penis is more thin and deli- cate than in most other parts of the body, and is furnished with a considerable number of sebaceous follicles, more particularly about the root of the organ. It is very loosely connected by cellular mem- brane to the parts beneath, so that it is easily made to correspond with all states of the penis. At the anterior extremity a duplicature or fold, the Pre- putium, is produced by it, which is inserted just be- hind the glans; and the inferior part of the prepuce is connected with the extremity of the glans by a process called Fraenum. The penis, besides arising from the bones of the pelvis in a manner which will be presently expressed, is fixed to the symphysis pubis by a ligament, (Ligamentum Suspensorium,) which is a triangular fibrous body, flattened transversely and lost insensibly on the fascia of the thigh covering the adductor muscles. The portion of it which goes to MALE PELVIS. 271 the penis arises in front of the symphysis pubis and is inserted into the dorsum of the penis near its root; from this insertion it is extended laterally over the penis, and according to Mr. Colles constitutes one of its coverings, going as far as the glans. Professor Marjolin says that he has seen on several occasions muscular fibres entering into its composition, and in that case it draws the organ with more force to- wards the anterior parietes of the abdomen. The Corpus Cavernosum of the penis, forms by much the most considerable portion of the whole organ. Externally it is a white fibrous membrane of a dense structure, enjoying extensibility and an extreme degree of contractility; its fibres passing for the most part longitudinally, except about the root where they are blended with the periosteum of the bone, and with the tendons of the muscles. This coat of the penis is occasionally called its elastic liga- ment. It arises by two conical crura, one from the internal face of the crus of each pubis and ischium to within a little distance of the anterior part of the tuber ischii. At the lower part of the symphysis pu- bis these crura join and form a body, which, when stripped of its connections, resembles two cylinders lying along side of each other and united; anteriorly they terminate in common by a truncated cone cover- ed obliquely by the glans. At the posterior part of the corpus cavernosum, in its centre, there is a tole- rably complete septum of the same kind of substance. 272 OF THE TRUNK. separating its two halves from each other, but ante- riorly this septum is imperfect, having an arrange- ment like the teeth of a comb, whence the term Sep- tum Pectiniforme. In the middle of the corpus cavernosum above, is a longitudinal sulcus for lodging the veins of the penis, and in the same manner below, another for the corpus spongiosum urethrae. The cavity of this membrane is filled by a spongy tissue, which arises from its internal face, and is formed of filaments and little laminae; they, by crossing each other, form a multitude of cells which have a perfectly free com- munication with each other, and generally are some- what occupied by blood. The Corpus Spongiosum Urethrae extends from ten or twelve lines behind the junction of the crura of the corpus cavernosum, to the anterior extremity of the penis. Externally it is covered by a coat re- sembling that of the corpus cavernosum, except that it is thinner, and in its centre is the canal for the urine; between the canal and the coat is a spongy structure, much finer than that of the corpus caver- nosum, and though the cells communicate freely, still they have the appearance of convoluted veins. The corpus spongiosum is not of the same thickness in its whole course, its commencement in the perineum where it is pendulous, is enlarged into what is termed its Bulb, from this it diminishes gradually to the end of the corpus cavernosum, where it is again enlarged MALE PELVIS. 273 into the glans penis. The transverse diameter of the glans being larger than that of the body of the penis, it forms all around a projecting shoulder, the Corona Glandis. The glans is covered by a very delicate epithelium, which shows a great number of papillae for the distribution of nerves. Several oblong tuber- cles also exist about the corona glandis, supposed to secrete the sebaceous fluid which collects 'there in persons who are not cleanly. The Urethra is a canal whose length varies ac- cording to the degree of erection in the penis, and extends from the neck of the bladder to the extremity of the glans. It has several curvatures and receives in its course the ductus ejaculatorii, the excretory ducts of Couper's glands, and the mucous lacunae of its internal membrane. The first part of this canal which traverses the prostate gland is about eighteen lines in length; it is the Prostatic Portion, and is well supported by this body, although its own sides are very thin. Here are to be found on its infe- rior surface the Verumontanum or Caput Gallinagi- nis, an oblong projection of the lining membrane an inch in length, broad behind where it commences a little in advance of the Uvula Vesicae, and coming to a point very gradually before: in its posterior ridge is a long cleft, which is the orifice of a large lacuna observed first by Morgagni; and near it, a little behind on each side, is the orifice of the ductus ejaculatorius. On each side of the caput gallinaginis m m 274 OF THE TRUNK. the canal of the urethra is depressed into something like a cul-de-sac, where are to be found from four to six very small orifices, or according to Loder from sixteen to twenty-two on each side, belonging to the lacunae of the prostate gland. Between the Prostate and the Bulb is the Membra- nous Part of the urethra, about eight or ten lines long; it is unprotected except by a soft covering which seems in some measure to be a mixture of gelatinous matter and muscular fibre. The former was consi- dered by Littre as a glandular body which secreted a viscid humour into the interior of the canal; the latter probably is the part described by Wrinslow as the inferior prostatic muscle, which arising on each side of the membranous canal goes to be inserted into the corresponding branch of the pubis near the symphysis. The membranous part of the urethra does not get into the end of the bulb, but penetrates it from above, half an inch or more occasionally, from its extremity, just below the junction of the Corpora Cavernosa. The canal varies in its dimensions; at its com- mencement it is large; it then contracts at the back of the caput gallinaginis and immediately enlarges in the fore part of the prostate. The membranous part is small; the canal enlarges in the bulb and forms, to- ward the basis of it, a shallow pouch, the Sinus Po- cularis, which may arrest the point of a catheter. At the middle of the penis the canal is again diminished. MALE PELVIS. 275 and just behind the glans it is so much enlarged as to get the name of Fossa Navicularis; it terminates by a short vertical slit at the extremity of the glans. In the whole length of the canal there are two whitish middle lines, one above and the other below, and in the membranous and spongy portions, except- ing the fossa navicularis, longitudinal folds of the lining membrane, which are effaced by distention. In the upper part of the canal there are a great many mucous lacunae; Loder, in his plates, has marked about sixty-five; there is one particularly large in the upper surface of the fossa navicularis, which, it is said, has stopped the point of a bougie and been mistaken for stricture.* At the posterior part of the bulb are Couper's Glands, two small bodies about the size of a garden pea. Their excretory ducts are about an inch long, and, passing very obliquely under the internal mem- brane of the urethra, they terminate at the anterior part of the bulb, in the lower side of the canal. Other glands, but smaller, of the same kind are said to ex- ist occasionally; I have never seen Them except in a preparation in the museum of Mr. Bell in London. * Sir Everard Home has lately communicated to the Royal Society a highly interesting paper on the structure of the lining membrane of the urethra. From his microscopical observa- tions he is induced to think that there can be no doubt of its muscularity. 276 OF THE TRUNK. Morgagni and Couper describe them. Marjolin says their existence is not constant, though they have been described by many anatomists. Mr. Shaw of London has described a set of vessels immediately on the outside of the internal membrane of the urethra, which, when empty, are very similar, in appearance, to muscular fibres. He says he has discovered that these vessels form an internal spongy body which passes down to the membranous part of the urethra, and forms even a small bulb there. See Med. Chir. Trans, vol. x. His preparation, with a quicksilver injection of the part, is certainly a very satisfactory demonstration of its existence. OF THE TESTICLES, (TESTES.) These bodies, two in number, are surrounded by several coats, the most external of which, formed of skin, is common to the two, and called Scrotum; the others are proper. The scrotum is a sac formed by a continuation of skin from the internal sides of the thighs, from the. inferior part of the penis, and from the anterior part of the perineum. It is very thin, darker than the rest of the skin, sparingly covered with hairs, has many sebaceous follicles in it, and is closely united to the cellular membrane beneath. It is very extensible, and has a great power of contrac- tion, its surface being covered with wrinkles which are more apparent when it is contracted. It consists MALE PELVIS. 277 of two symmetrical halves marked off from each other by an elevation of skin, the Rapha, which extends from the perineum over the scrotum along the infe- rior surface of the penis to the end of the latter. Beneath the scrotum is the Dartos, a fibrous mem- brane, which is vascular, reddish, and deprived of fat; it arises from the inferior margins of the crura of the ischium and pubis, and passing downwards, it joins the rapha; it is then reflected upwards, forms a sep- tum between the two sides of the scrotum, and goes up to the inferior part of the urethra.# This mem- brane has been confounded with cellular substance, but it appears from the reports of Messieurs Chaus- sier, Lobsteiu, and Breschet, that it does not exist in the scrotum till the descent of the testicle, and that it is an expansion of the gubernacuium testis. Notwithstanding its great contractility, the ques- tion of its muscular structure is not settled, and cer- tainly, in the greater part of its extent, there is not much appearance of muscular fibre, but at its poste- rior part, just at the anterior point of the sphincter ani, I have often seen a broad muscular expanse, the character of which could scarcely be misconceived. The contractility of the scrotum has been attributed to the cremaster muscle instead of to this membrane, but common observation will convince most persons that the elevation of the testicles in the scrotum by the contraction of the cremaster is very distinguish- able from that contraction of the scrotum by which 278 OF THE TRUNK. the testicles are squeezed against the sides of the pu- bis and the scrotum brought into a hard corrugated mass. The Cremaster muscle is rather an imperfect coat; its course has been explained in the account of the abdominal muscles. Its fibres are much separated on the tunica vaginalis, lying on its front part and on the internal and external sides of the spermatic cord. The Tunica Vaginalis Testis was originally a pro- cess of peritoneum, though it appears in the adult as a complete sac. It is reflected from behind over the epididymis and testicle, being very closely connected to them; and in front it is loose like nearly all the other reflected membranes. It passes up some dis- tance on the cord; its internal cavity is smooth, po- lished, and moistened by a synovial halitus which al- lows the surfaces to move freely upon each other. Its exterior connection is so slight that it may be with- drawn from the dartos membrane with but little force. The Tunica Albuginea is the proper coat of the testicle which preserves its form, and is in immediate contact with the glandular structure. It is a dense, strong, white, and fibrous membrane, corresponding very much in its general characters with the tunica sclerotica of the eye. From the internal surface of the albuginea, several membranous processes forming partial partitions pass off, and terminate at the pos- terior part of the cavity in the Corpus Highmori- anum. These septulae conduct the blood-vessels MALE PELVIS. 279 through the substance of the gland, and form little apartments filled up by the seminiferous tubes. The corpus highmorianum is a longitudinal projection of the tunica albuginea, somewhat broader above than below; its upper part is perforated by the vasa effe- rentia. The form of the testicle as communicated by the tunica albuginea, is very much that of an oval, some- what compressed laterally, the edges presenting for- wards and backwards; it does not hang with its long diameter vertical, but the upper end is advanced a little forwards, and the lower points somewhat back- wards. They are both of the same size generally, but in case of a difference the right preponderates; it is also higher up than the left, a circumstance which has been marked by sculptors in all ages. The parenchymatous structure of the testicle con- sists of a congeries of convoluted tubes, stated by Monro to amount to three hundred, whose diameters do not exceed individually the one two-hundredth part of an inch, and when extended to their full length in the aggregate, would form a tube 5208 feet long. These tubes, almost inconceivably fine as they are, can be injected in a retrograde course through the vas deferens with mercury, but the task is one of exceed- ing difficulty, and scarely ever succeeds. This is con- sequently a very rare preparation in anatomical cabi- nets; I have seen but two. One made by Mr. Shaw of London for the Museum of Mr. Bell, and the 280 OF THE TRUNK. other at Leyden, made by the present Professor San- difort. Haller has introduced the plate of one in his Opusculum Minus, which was highly distinguished in its time, but in this the mercury does not seem to have pervaded fully the tubuli seminiferi, notwith- standing which, it went far to establish the structure of the testis, and to settle the dispute in regard to the organization of the corpus highmorianum. The Tubuli Seminiferi, it has been stated, fill up nearly the whole of the cavity of the albuginea, being kept from each other by the processes termed Sep- tulae. Towards the back of the testis these tubes send out a great number of trunks, which, from their observing a strait course, obtain the name of Vasa Recta. These vasa recta unite and form a net-work, the Rete Testis. From the rete testis there proceed from twelve to eighteen tubes, which pass through the upper part of the corpus highmorianum, and get to the outside of the tunica albuginea; these are the Vasa Efferentia. Each of these vasa is rolled up ex- ternally so as to give the outline of a cone, at this place, therefore, it gets the name of Conus Vasculo- sis. Each cone successively empties into a single tube on the back of the testes, which is prodigiously convoluted and forms a large body, the Epididymis. The Epididymis is a triangular arch enlarged at both extremities, and seeming to rest vertically on the testicle at its back part, being connected with it by the tunica vaginalis. The enlargement above is the MALE PELVIS. 281 Globus Major, and is formed of the coni vasculosi, and what remains of this body below consists of one tube excessively convoluted. The enlargement be- low is the Globus Minor; after this is formed, the tube becomes less convoluted and turns upwards on the inside of the epididymis, and a little further on it becomes nearly straight, and is called Vas Deferens. There is a blind duct which commences at the top of the epididymis and terminates below, the inten- tion of which is not known. The Vas Deferens is a white tube about two lines in diameter, having a cartilaginous feel; its cavity is large enough to admit a bristle. It passes on the back of the spermatic cord and continues with it through the abdominal canal; at the internal ring it leaves the residue of the cord, and dipping into the pelvis by the side of the bladder it passes between it and the ureter to the lower fundus, approaching its fellow on the inside of the vesicalae seminales and ending in the prostate gland. About two and a half inches from its termination it becomes somewhat tor- tuous and enlarges. The Spermatic Cord is formed of the Vas Defe- rens, the Spermatic Artery and Veins, Lymphatics, Nerves, and Cellular Membrane, all covered by the Cremaster muscle. The artery arises from the aorta and keeps its proper size till it arrives at the testis, it then divides, some of its branches being spent on the epididymis, and the remainder going into the testis and n n 282 OF THE TRUNK. terminating on the tubes. The veins in ascending form a remarkable plexus, the Corpus Pampiniforme, at the internal ring they have united into one trunk which on the right joins the ascending cava, and on the left the emulgent vein. Having thus become acquainted with the structure of the viscera of the male pelvis, I advise the student in the next place to put a subject in the posture re- commended for Lithotomy, in order that he may work on the Perineum. Section II. OF THE PERINEUM AND THE FASCLE OF THE MALF PELVIS. The subject being fixed in the posture indicated, make a horizontal cut at the junction of the rapha of the perineum with the scrotum, through the skin extending it on each side three inches, drop perpen- dicular cuts of the same depth from both extremities of the first, to a line which would pass horizontally through the extremity of the os coccygis. The skin constituting this flap being raised up carefully, so as not to cut deep enough to injure subjacent parts, the structure of the perineum is sufficiently opened for the time. MALE PELVIS. 28S The Perineal Fascia is first exposed; it occupies nearly all the space between the anus and the poste- terior margin of the scrotum, (insensibly blending with the latter,) and between the rami of the pubis and the ischium on each side, being very firmly fixed to these bones. This fascia, in case of rupture in the posterior part of the urethra, prevents the urine from showing itself in the perineum, and drives it into the cellular structure of the scrotum. In ab- scesses of the perineum, it also prevents the fluc- tuation from being very evident. Having studied well its connections, structure and influence, it is to be cleared away in order to bring into view the Perineal Muscles. The Erector Penis is so situated as to cover the whole of the crus of the penis which is not in contact with the bony margin of the pelvis. It arises, there- fore, from the anterior part of the tuber ischii tendi- nous and fleshy, its fleshy fibres, adhering to the in- ternal and external margins of the rami of the pubis and ischium, proceed upwards, and, just before the crura of the penis unite, it ends in a flat tendon which is lost on the side of the elastic membrane of the penis.* Its use is not well understood. The Accelerator Urinae lies on the bulb and * Dr. Laurance informs me that he has frequently found muscular fibres between the bone and the crus penis. ^84 OF THE TRUNK back part of the corpus spongiosum urethrae; it is a thin muscle consisting of oblique fibres. It arises by a pointed production from the side of the body of the penis; its origin is continued obliquely across the inferior surface of the crus penis where it begins to form the body of the penis. It arises also from the inner side of the ramus of the pubis be- tween the crus penis and the triangular ligament of the urethra. The muscles of the opposite sides are inserted into each other by a white line which marks the middle of the bulb of the urethra, and by a point into the anterior extremity of the sphincter ani, where they are joined by the transversales perinei. In order to see the origin of these muscles very distinctly, separate them from each other in the mid- dle line and dissect them from the corpus spongiosum. Cut transversely through the corpus spongiosum about three inches before the triangular ligament and dis- sect it clearly from the corpus cavernosum, turning it downwards so that it may hang by the membranous part of the urethra. By putting the two accelera- tores on the stretch it will be seen that, besides the origins mentioned, they arise also from each other by a tendinous membrane that is interposed between the corpus spongiosum and cavernosum, so that they li- terally surround the bulb of the urethra constituting a complete sphincter muscle for it. These two muscles are considered by M. Chaus- sier as forming but one; in that case its origin will be MALE PELVIS. 285 reversed, and commence in the middle line of the pe- rineum instead of terminating there. The contact of this muscle and the erector penis should be observed in order to appreciate the difficulty of getting into the membranous part of the urethra in lithotomy without cutting through the muscular fibres of one or the other. It propels the urine and semen forward. The Transversus Perinei, as its name implies, passes directly across the perineum; it arises from the inner side of the tuber ischii just at the origin of the erector penis, and is inserted where the sphincter ani and acceleratores join. I have observed that when the lower part of the acceleratores was extended much below its usual line and strongly developed, that the transversus was very irregular in its origin and course, consisting frequently of a few fibres which did not deserve the name of a distinct muscle, and lying almost unappropriated in the adipose matter of the part. Occasionally a fasciculus of muscular fibres exists, called, by Albinus, Transversus Perinei Alter, which arises in front of the former muscle, and is inserted into the perineal junction just behind it. The use of these muscles seems to be to contribute to fix the bulb of the urethra. The Sphincter Ani muscle consists in a plane of fibres which surrounds the anus in order'to keep it closed. It has two fixed points, the last bone of the 286 OF THE TRUNK os coccygis behind and the perineal union of the other muscles in front; its lateral diameter occupies about one-half of the space between the tuberosities of the ischium, as it is in the middle of this space. Besides closing the orifice of the rectum it will draw the bulb of the urethra backwards, or the point of the os coccygis forwards. The Coccygeus muscle rather belongs to the inte- rior of the pelvis, but is well enough seen here. It arises by a small, tendinous, and fleshy beginning from the spine of the ischium, and, lying on the an- terior face of the anterior sacro sciatic ligament, it is inserted into the sides of the last bone of the sacrum and of all those of the os coccygis. It draws the os coccygis forwards. The Erectores Penis, Acceleratores Urinae, and Transversi Perinei are now to be removed. A large quantity of adipose and cellular matter will be found on the side of the rectum between it and the parietes of the pelvis, concealing the levatores ani muscles, which it is better to leave for the present in situ. The muscles being removed, the bulb of the ure- thra is seen to great advantage extending in the mid- dle of the perineum almost to the anus. It is not loose and pendulous as described, but is connected by its superior face to the Triangular Ligament of the urethra, a membrane which fills up the space below the symphysis of the pubis. This ligament is a sep- tum between the perineum and pelvis, and, when MALE PELVIS. 287 closely examined, is seen to connect itself to the in- ternal edges of the rami of the pubes and ischii on the inner posterior sides of the crura penis as far down as the origins of the latter. At its lower edge its liga- mentous character is not so well defined. It extends from the top of the pubic arch downwards to the line mentioned, filling up all the intermediate space be- tween the bones. On its anterior surface is the bulb of the urethra, and just at the extremity of the lat- ter, enclosed by the ligament and adhering to it, are Couper's Glands. A perforation exists in it through which passes the membranous part of the urethra*, to get a view of which the corpus spongiosum must be cut through an inch anterior to the symphysis pubis, dissected carefully from the corpus cavernosum, and turned down on the perineum. The opening at first is not very; apparent in consequence of its edges be- ing continued a little distance on the canal, but by detaching them the hole becomes well defined. Here it becomes necessary to attend to the relative situation of the bulb, and of the membranous part of the urethra. The former has just been described going towards the anus, the latter passes upwards towards the neck of the bladder, they consequently form a considerable angle with each other, and the membranous part of the urethra is much the deepest, the recollection of which is all important in lithotomy, as it teaches us to avoid the one, and to cut into the other. It will also be observed that the hole in the 288 OF THE TRUNK. triangular ligament is an inch below the edge of the symphysis pubis. By dissecting off the upper corner of the triangular ligament, we are made acquainted with another just behind it which is totally distinct. This ligament is half an inch broad, thick and strong particularly at its lower edge, and is very firmly attached laterally to each pubis just below the symphysis. Mr. Colles calls it pubic ligament, with great propriety; I would sug- gest, as somewhat more expressive, the term Inter-Pu- bic ligament, as it serves to distinguish it from another called pubic, which is above the pubis* The breadth of this having been stated at half an inch, it is obvi- ous that the hole in the triangular ligament is half an inch below its lower edge. We have now seen as much as can be viewed ad- vantageously from the perineum at this stage of the dis- section, and I recommend an inspection of the parts from above on the side of their abdominal surfaces. The pelvis is therefore to be separated from the trunk at the last lumbar vertebra and the posterior part of the pelvis to be removed, sawing through the os ileum from its crista to the upper margin of the sciatic notch on each side; the os coccygis however must remain in situ, as it is very material to the description of the Levatores Ani muscles. Care must be taken not to injure the rectum in these sections. * See Abdominal Muscles MALE PELVIS. 289 Begin by raising the peritoneum from the anterior surface of the rectum, after which by letting the rec- tum fall backwards and putting the raised peritoneum on the stretch, an excellent view is obtained of the line of attachment of the latter to the lower part of the bladder. It is seen that the peritoneum is reflected from the bkdder at the posterior end of the vesiculae seminales, but that a pouch or process of it is sent down between them which goes within a short dis- tance of the prostate gland, and that a very small space of the bladder lies naked below this process of the peritoneum, which can be punctured from the rectum without injuring either the cavity of the peritoneum or the vesiculae seminales. By distending the bladder moderately, the different reflections of the peritoneum from it to the abdomi- nal parietes and to those of the pelvis will be better understood, and the possibility of puncturing the for- mer above the pubis without getting into the cavity of the abdomen will be demonstrated fully, as well as the freedom with which its neck may be divided in the lateral operation for the stone. Next strip the peritoneum from the sides of the pelvis, which brings into view the Aponeurosis Pelvica connecting the bladder to the sides of the pelvis. " This fascia descends from the ileo-pectineal line to about midway in the depth of the pelvis; here it is reflected from the suiface of the muscles (the Leva- tores Ani) and applies itself to the prostate gland and o o 290 OF THE TRUNK bladder, on the body of which it is ultimately lost. A1- ihe angle of its reflection this fascia appears parti- cularly strong and white, but becomes more weak and thin as it lines the muscles and covers the bladder." In tracing this membrane it will be seen that from the pubis just below the symphysis, a pointed pro- duction of it constituting its anterior margin is fixed into the side of the neck of the bladder. This point- ed production on each side is called by most anato- mists the Anterior ligaments of the bladder. Between them just beneath the symphysis of the pubis a pouch large enough to receive the end of the finger is formed by the union of the fasciae of the two sides; this pouch connects the middle anterior part of the neck of the bladder to the lower margin of the sym- physis pubis." A good account of this fascia is published by M. Breschet in his Thesis on Hernia, p. 130, presented to the Faculty of Medicine in Paris for the place of Chef des Travaux Anatomiques in the year 1819. He says, " that when the aponeurosis which covers the iliac fossa arrives at the internal margin of the iliacus internus and psoas magnus muscles, near the superior strait of the pelvis, it plunges into this cavity in order to line its sides and to cover the muscles which are applied on its several openings. Having got very low down it embraces the rectum, is reflect- ed upon the bas-fond of the bladder, the prostate gland, and in woman upon the vagina. From which MALE PELVIS. 261 cause these viscera may be said to be in part in the cavity of the pelvis, and partly out of it; if we consider this cavity as the space on the outside of the aponeu- rosis. Some practitioners have observed that the consequences of the operation of lithotomy are dif- ferent when the instrument penetrates more or less deeply behind or on the side. Inflammations, suppu- rations, abscesses in the cavity of the pelvis occur when the instrument is thrust in too much, while no such accidents follow an instrument introduced mode- rately deep. Distinguished practitioners* have asked the reason of these differences, and I believe that I have found them in the arrangement of the aponeu- rosis pelvica. If the instrument does not penetrate beyond this fascia, there is no abscess in the pelvis, or if a small quantity of pus be formed, it readily finds an issue externally. On the contrary, if the pelvic aponeurosis be injured, inflammation deve- lops itself, suppuration takes place beyond this apo- neurotic barrier, the liquid cannot get out, and it makes ravages which sometimes cause the death of the patient." This description of the aponeurosis pelvica is true, but rather too general; the.most common condition of it is found to be as follows. It adheres closely to the periosteum of the pubis between the upper mar- gin of the thyroid foramen and the crista of the pu- * Scarpa's Memoir on Hawkins' Gorget. 292 OF THE TRUNK. bis; about the middle third of the linea innominata it is obviously a continuous membrane with the iliac fas- cia, but behind this again it arises from the remain- ing third of the linea innominata. The portion of this fascia which Mr. Colles speaks of as particularly strong and white, forms a bow, the concavity of which looks upwards, one end of the bow being fastened to the pubis above the foramen thyroideum, and the other end to the spine of the ischium. The perineal surface of this bow is an im- portant point of the origin of the levator ani. Above the bow this fascia is very thin, for the fibres of the obturator internus can be readily seen through it. At the bow this fascia divides into two laminae, one having the course indicated, the other covers the lower part of the obturator internus muscle constituting the obturator fascia. The levator ani is interposed be- tween the two laminae. The aponeurosis pelvica also forms a bow or semilunar edge in front of the sacral nerves. The levator ani muscle is essentially connected with the aponeurosis pelvica. In order then to get a view of it, make a cut through the fascia, from the symphy- sis pubis backwards to the sciatic notch about half an inch above the middle of the fascia. As the muscle is placed nearer to the perineum, the fascia must be turned down towards the bladder as low as possible, the upper surface of the muscle is thus exposed, and also the manner in which it may be said to arise, MALE PELVIS. 293 particularly at its posterior part from the under or perineal surface of the fascia. The Levator Ani muscle arises fleshy from the back of the pubis near its symphysis, and from near the superior margin of the foramen thyroideum above the obturator internus muscle. It also arises from the aponeurosis pelvica, where this membrane is ex- tended as a thickened semilunar cord from the supe- rior margin of the thyroid foramen to the spinous process of the os ischium. This second part of the origin of the levator ani is defectively described in most books on anatomy. It is then seen to cross ob- liquely, as far as the spine of the ischium, that portion of the obturator internus which arises from the plane of the ischium. From this extensive origin the fibres converge and descend backwards, and have three distinct places of insertion; the posterior fibres are inserted into the two last bones of the os coccygis; the middle, and by far the greater number are inserted into the semi- circumference of the rectum between its longitudi- nal fibres and the circular fibres of the sphincter ani; and finally, the most anterior fibres pass oliquely downwards and backwards on the side of the vesical end of the membranous part of the urethra and on the side of the prostate gland, and are inserted into the common point of the perineal muscles. These insertions of the levatores ani, to be well understood. 294 OF THE TRUNK. must be studied both from the perineal and abdomi- nal surfaces. It yet remains to speak more definitively of the tri- angalar ligament; it has been seen from the perineum, and is now to be viewed from the pelvis. Bemove the anterior part of the levatores ani; the ligament is then seen occupying the interval under the symphysis and between the rami of the pubes and ischii, extend- ing downwards an inch and a half. Its base or infe- rior edge is crescentic, and half an inch above the base is the hole for the membranous part of the ure- thra. This hole is, in fact, not very distinct, for the triangular ligament is reflected backwards from its edges along the membranous part of the urethra, which obscures the hole. The prostate gland also gets a li- gamentous capsule from a continuation of this same reflection, and is thereby very firmly fixed in its place. The edges of the triangular ligament, fastened to the side of the pelvic arch, are continuous with the fascia covering the obturator internus muscle. The triangular ligament is a membrane consisting of two laminae; the bulb of the urethra is fastened to the an- terior lamina, and the prostate gland is fixed to the posterior lamina; between these laminae above is the interpubic ligament and several blood-vessels derived from the vena ipsius penis. Mr. Colles says: " If we attempt, in conformity to the custom of anatomical writers, to describe all these continuous fasciae which connect the bladder and MALE PELVIS. 295 urethra to the pubis, as productions of one and the same fascia, we might say that the triangular liga- ment, by its outer edges, is fixed into the rami of the pubes and is there continuous with the liagment lining the obturator muscles, that the edges of the opening for receiving the membranous portion of the urethra are produced backward along the prostate, and hav- ing ascended as high as the arch of the pubis, it there splits into two laminae, one continuing its course over the upper surface of the gland and bladder, the other lining the upper portion of the levator ani." The description of the fasciae of the pelvis is one of the most difficult and perplexed in the whole range of anatomy, and the proof of it is that almost every writer on the subject considers the labours of his pre- decessors imperfect, and, with a very laudable spirit, hoping to improve the defect, invites the attention of the profession to his new views. In this, however, I do not participate, and feel equally happy in draw- ing materials from Mr. Colles's excellent work on Surgical Anatomy. Here I cannot help expressing a regret that a gentleman whose views are so lumi- nous on a most intricate subject should have con- fined his descriptive talents within such small boun- daries as those of his Surgical Anatomy. PART II. CHAPTER IV Of the Organs in the Female for the Generation and Nourishment of the Infant. Section I. OF THE FEMALE PELVIS. r The viscera of the female pelvis should be first studied in their natural situations; they should then be removed and dissected neatly for more satisfactory examination. The whole study may afterwards be concluded with a side view, as in the male subject. The Female Pelvis contains the Urinary Bladder and Rectum, besides the Organs of Generation. The two first do not demand particular description here, as enough has been said concerning them in the account of the male pelvis. The Organs of Generation are situated between them, and consist of the Vulva ex- FEMALE PELVIS. 291 ternally,of the Vagina in the middle, and of the Ute- rus with its appendages internally. Under the term Vulva we consider the Mons Ve- neris, the Labia Majora or Externa, the Labia Mi- nora or Interna, the Clitoris, the Vestibulum, the Orifice of the Urethra, the Fourchette, and the Fossa Navicularis. The Mons Veneris is an eminence on the fore part of the pubes which is produced by the deposit of a great quantity of fat under the skin. In very cor- pulent women its size is occasionally enormous. The skin covering it, at the age of puberty, is studded with hair, and under it is a considerable number of sebaceous glands. On each side of the mons veneris an oblong eminence is continued from below; they are the Labia Externa which unite with each other by the fourchette at the anterior part of the perineum. These labia are protruded in the same way with the mons veneris by a deposit of adipose matter beneath their skin or integuments; they are broader and more prominent above than below. On the side which looks to the thighs they are covered by the common skin, but on the internal face the integument is form- ed by a kind of mucous membrane, a continuation of that in the vagina. These bodies are only partially covered with hairs, but have many sebaceous glands externally, and mucous orifices internally on them. In their interior structure much cellular mem- p p 298 OF THE TRUNK brane, like that of the scrotum, is found, possessed of great extensibility in order to favour the dilatation of the parts in parturition. Between them is a lon- gitudinal rima about twice the length of the orifice of the vagina for favouring still more the expulsion of the foetus. It is the Fissura Vulvae of authors. The Clitoris is a small body corresponding, in part, with the male penis, situated between the upper extremities of the labia externa on the lower part of the symphysis pubis. It is furnished with a suspen- sory ligament, and curved towards the urethra. It consists of a body and of two crura; the body is about an inch long, and the crura each of the same length, having their attachments to the internal faces of the crura of the pubes and ischia. It is covered by an elastic ligamentous membrane, and has an internal spongy body capable of erection like the penis, divid- ed by a septum pectiniforme, and having a similar supply of blood-vessels and of nerves. It has also an erector clitoridis muscle lying upon its crus and ex- tended to the side of its body in the same way with the erector penis. The extremity of the body of the clitoris project- ing into the upper part of the bottom of the rima is called its Glans, but it does not resemble, in structure, the glans penis. A kind of hood is thrown over it by a duplicature of the integuments of the part, which gives some resemblance to the prepuce; it is there- FEMALE PELVIS. 299 fore called the Prepuce, (Preputium.) This prepuce is occasionally much elongated and its orifice con- stricted, so that the secretion from its mucous cryptae is imperfectly discharged and produces much itching and irritation. Mr. Marjolin relates the case of a Spanish girl of four years in whom he performed cir- cumcision successfully, in order to free her of a very bad habit to which she was addicted in consequence of this disease. The Labia Interna, or Nymph^e, are two mem- branous productions passing downwards, one from each side of the prepuce. They arise from the in- ternal sides of the labia majora, are seldom so broad naturally as to project beyond them, and, being wider in the middle than elsewhere, they terminate insensi- bly about half-way down the orifice of the vagina. They consist principally of a duplicature of the mu- cous membrane of the part, between the laminae of which is placed a vascular cellular membrane giving to them, when excited, a somewhat erectile condition. In young subjects their vascularity gives them a ver- milion tint, which is lost in the progress of life. They are supposed to direct, in some measure, the stream of urine; but it is more probable that, as they are effaced during parturition, they facilitate the enlarge- ment of the vulva. The Vestibulum is the triangular space at the 300 OF THE TRUNK. upper part of the rima, bounded by the clitoris above and the nymphae laterally; in it are many mucous follicles. At the middle inferior part of the vestibulum, about an inch below the glans clitoridis, is the Ori- fice of the Urethra, (Orificium Urethrae.) It belongs to the canal leading from the bladder, and is generally marked by a slight rising or tubercle which is easily distinguished by the sensation of touch alone; its lips are closed by a little caruncle on each side. The urethra itself is an inch long, larger and much more dilatable than that of the male; its course is obliquely downwards and forwards from the neck of the blad- der, passing under the symphysis of the pubis, and be- ing slightly curved from that cause. It consists of two membranes, a lining and an external one. The lining membrane is a continuation of that of the blad- der; it is thrown into several longitudinal folds, and has many mucous follicles in it. The external coat of the urethra consists of condensed laminated cellu- lar membrane forming a cylindrical body of half an inch in its transverse diameter, which has given the idea of the existence of a prostate gland in the fe- male. The lower and lateral surfaces of this cylin- der are in contact with the vagina, forming a protu- berance into its cavity, and the upper surface is firmly connected to the triangular ligament of the pubis. FEMALE PELVIS. 301 The Fourchette, or Frenulum Vul'vje, is situ- ated at the inferior junction of the labia externa; it is a narrow duplicature of skin extending across the vulva from one side to the other, and is, most fre- quently, ruptured at the first parturition. That por- tion of the rima betwixt it and the orifice of the ure- thra is called, by many anatomists, the Fossa Navicu- laris. The Vagina, is the intermediate part of the sex- ual organs, extends from the Vulva to the Uterus, be- ing placed between the Bladder and Rectum, and compressed anteriorly and posteriorly by them. In virgins its external extremity is contracted into a smaller canal than the internal, and besides this, is closed by a membrane called the Hymen. The Hymen, situated just within the orifice of the vagina, is a partial septum formed by a reflection or duplicature of its lining membrane; it varies very much in shape, breadth, and thickness. Most com- monly it is crescentic and fixed to the inferior part of the vaginal orifice by its convex edge, the horns being upwards, in other cases it is to the side. Sometimes it is a circular membrane having a hole in the centre. It is generally so weak^jtftat it is ruptured at the first act of copulation,, feffu occasionally so resisting that it has required artificial division to make it yield even to the expulsive efforts of the uterus in parturition. 302 OF THE TRUNK. Its presence then is not invariably a proof of virginity, nor is its absence a proof of improper indulgence. The vagina is a membranous canal of about five or six inches in length, varying however according to age and pregnancy, being much shorter in women who have borne children than in virgins. Its shape varies somewhat, near the vulva its greatest diameter is vertical, but behind near the uterus the greatest diameter is transverse. Its anterior and posterior surfaces are in contact from the circumstances just mentioned of pressure between the bladder and the rectum. It is shorter before than behind, correspond- ing in this respect with the pelvis by wrhich it is influenced, and also in consequence of being at- tached to the uterus higher up on the sacral than on the pubic side. The peritoneum, in descending from the uterus anteriorly, touches the top of the vagina for a little distance and is then reflected to the bladder, but pos- teriorly nearly the upper half of the vagina has a peritoneal coat before this membrane is reflected to the rectum. The attachment of the vagina to the bladder is strong and close just about the urethra, but its connection to the rectum is by rather loose cellu- lar membrane. It consists of two coats, a fibrous and elastic one externally, and a mucous one internally. The first is of a reddish colour and seems to be formed of condensed cellular membrane, its fibres not passing FEMALE PELVIS. 303 in any determinate direction. Many blood-vessels are found in its structure, and it has an abundance of large venous sinuses surrounding it. On the anterior part of this coat externally, there is a flat spongy body, (Corpus Spongiosum Vaginae,) about one inch broad and a line or two thick, which is placed on its superior and lateral surfaces, covering about one-half or two-thirds of the whole circumfe- rence of the vagina. The structure of this body closely resembles that of the corpus spongiosum urethrae, and from being very vascular is probably subject to distention in its cells during sexual ex- citement. This body is covered by the sphincter va- ginae muscle. The Sphincter Vaginae arises from the body of the clitoris, forms an expanse of an inch and a quarter around the anterior end of the vaginae, and is inserted into a dense whitish substance in the centre of the perineum, common to it, the sphincter ani and the transversi perinei muscles. The transverse perineal muscles existing in the female, have the same circumstances of origin and insertion, but are not so strong as in the male. Anterior to the corpus spongiosum on each side of the vagina, near its middle, is a mucous gland about the size of a garden pea, which is the Couper's gland of the female. To bring into view satisfactorily the internal mem- brane of the vagina, the canal should be slit up late- 304 OF THE TRUNK. rally from its external orifice to the uterus; this mem- brane being mucous will then be observed as continu- ous with the mucous membranes of the vulva and uterus. Near the vulva it is of a vermilion tinge, but near the uterus it is greyish with several dark spots giving it a marbled appearance; its thickness diminishes as it recedes from the external orifice. In females in whom the hymen is ruptured its place is indicated by from two to six small tubercles, the Carunculae Myrtiformes. On its anterior or pu- bic wall the internal surface of the vagina is divided longitudinally by a ridge commencing in a sort of tubercle at the anterior orifice of the vagina just under the meatus urinarius; this ridge proceeds back- wards, but becomes indistinct in approaching the uterus; from it on each side proceed transverse ridges or folds'of the mucous membrane, which are parti- cularly numerous and prominent before, but become indistinct and irregular near the uterus. The infe- rior side of the vagina has the same sort of arrange- ment as the superior, only not so well marked. By cleaning the vagina and suspending it in water an abundance of mucous cryptae may be observed on its whole internal surface, which by an increased dis- charge produce leucorrhcea. FEMALE PELVIS. 305 the uterus and its appendages, the fallopian tubes and ovaria. The Uterus is a compressed pyriform body with a cavity in its centre, which is placed between the blad- der and rectum; having the small intestines above it, and the vagina below. Unimpregnated it is two inches and a half long, and an inch and a half wide at its broadest part; its anterior surface is much flatter than the posterior. It is divided into fundus, body, and neck. The fundus is the superior convex edge, the neck the narrow part below about an inch long, and the body the portion between these two. The uterus is maintained in its situation in the centre of the pelvis by the reflections of the perito- neum, which are called ligaments. The peritoneum, after covering the uterus completely is reflected an- teriorly upon the vagina, and at each side of this re- flection is a duplicature of the membrane denominated the Anterior Ligaments, which go to the bladder. The peritoneum in passing from the back part of the uterus to the vagina and subsequently to the rectum, has on each side of this reflection also a duplicature, which constitutes the Posterior Ligaments. The peritoneum is also reflected from the whole length of each side of the uterus to the corresponding part of the cavity of the pelvis; these reflections are termed the Lateral or the Broad Ligaments. The peritoneum covers Q q 306 OF THE TRUNK. much more of the vagina posteriorly, than it does anteriorly. These Broad Ligaments, with the uterus, form a transverse septum in the middle of the pelvis. At the superior edge of this septum, on each side, is the Fallopian Tube, and on the posterior face of the sep- tum, below the edge and about an inch or a little more from the uterus, on each side, is an Ovarium. The peritoneum adheres to the uterus by a cellular tissue, which is somewhat loose and can be easily dis- sected from it. Besides the ligaments mentioned, the uterus has two more, one on each side, called the Round Liga- ments. They arise from the side of its body, between the duplicatures of the broad ligaments, and pass un- der the peritoneum to the abdominal ring, through which they penetrate and are lost upon the fat of the labia majora. They are of a fibrous structure, and have many blood-vessels in them. The neck of the uterus is enclosed by the cavity of the vagina in such a way that it projects into the lat- ter. In the centre of this projection is the Orifice of the Uterus, (Os Tincae,) which is not perfectly cylin- drical but somewhat flattened or oval; this orifice is bounded before and behind by the lips or projections of the neck, which are transverse. The posterior lip is somewhat thinner than the anterior, but, in conse- quence of the insertion of the vagina on that side be FEMALE PELVIS. 307 ing higher up, it projects more into the vagina and is easily distinguished by the finger. Behind the os tincae is the Cavity of the Neck, which is a paraboloid cylinder, larger in the middle than at either end; its termination forwards is about the size of a small writing quill, the posterior extre- mity is somewhat larger. In the middle of this ca- vity, before and behind, longitudinally, is a line form- ed by an elevation of the lining membrane, and on each side of this line, transversely, there .are others presenting an arborescent arrangement. This is the Arbor Vitae. In the interstices of the transverse lines there are small mucous glands called Ovula Nabothi, in consequence of this anatomist mistaking them for eggs. The cavity of the body of the uterus is triangular, the sides of the triangle being curved inwards so as to present their convexities to its cavity. The cavity is nearly equilateral, and has its anterior and posterior surfaces in contact; the angle below is continued into the cavity of the neck, and the angles above are con- tinuous with the fallopian tubes, being extended very far through the parietes of the uterus in order to meet them. This cavity is divided into two symme- trical halves by elevated lines on its anterior and pos- terior surfaces running from above downwards. It is said that, in some cases, they have formed a com- plete partition. The internal membrane of the uterus is a conti- 308 OF THE TRUNK. nuation of that of the vagina, and adheres so closely that its existence has been doubted. It has very little thickness, is extremely smooth, and presents villosi- ties so fine that they are seen with difficulty by the naked eye. It is of a light pink colour, which changes into a deeper vermilion a few days before and during menstruation. It abounds with mucous cryptae and exhalent orifices. The texture of the uterus is essentially fibrous and of a whitccolour tinged with red, from having a great number of blood-vessels in its composition. The fibres have no determinate course, but are blended and interwoven in every direction. Its muscularity is not apparent in the unimpregnated state. The Fallopian Tubes, (Tubae Uterinae,) are two membranous canals fixed, as mentioned, in the upper edges of the broad ligaments. They are about four inches long, somewhat serpentine, and extend from the upper angles of the uterine cavity to the sides of the pelvis. At their uterine extremities these tubes scarcely admit a hog's bristle, but as they proceed ex- ternally, about half-way of their length, they begin to increase and continue to do so very rapidly almost to their termination, where they become somewhat con- tracted, and immediately afterwards end by an ob- lique edge, singularly fringed, called Morsus Diaboli, or Corpus Fimbriatum. This latter part of the tube FEMALE PELVIS. 309 is loose and pendulous, overhanging the ovarium on the back part of the broa^ ligament. The Fallopian Tube seems to be a continuation of the structure of the uterus, having a fibrous mem- brane externally and an internal mucous one; the latter is principally concerned in forming its large extremity, and is probably rendered erectile in sexual excitement by its great vascularity. The Ovaries, (Ovaria, Testes Muliebres,) are si- tuated one on each side of the uterus and on the pos- terior face of the broad ligament enclosed in a dupli- cature of it. They are compressed ovoids about half the size of the testicle, of a very light pink colour; are connected to the uterus by a small vascular and fibrous cord called Ligament of the Ovary, which is inserted into the uterus just below the fallopian tube. The external end of the ovary has one of the pro- cesses of the corpus fimbriatum or morsus diaboli adhering to it. The surface of the ovary is rendered somewhat uneven by a number of round projections and marks resembling cicatrices. It has a complete peritoneal coat, and within this is another of a strong, compact, fibrous character sending many processes internally, which corresponds with the tunica albuginea. The structure of this body is imperfectly known; a good deal of vascular fibrous matter enters into its composition, containing from fifteen to twenty vesi- 310 OF THE TRUNK. cles of various sizes from the head of a small pin to a French pea. The parietes of these vesicles are very thin, transparent, and vascular, and contain an albuminous light coloured fluid. The Bladder and Rectum, with unimportant ex- ceptions, are the same in both sexes. The arteries of the viscera of the pelvis, in both cases, are derived from the internal iliacs. The Levator Ani, Coccygeus, and Sphincter Ani muscles have the same arrangement as in males. The Fasciae connecting the bladder to the sides of the pelvis and the triangular ligament of the urethra also exist. Section II. OF THE FEMALE MAMMJE. The Mammae are two glandular bodies situated over the thorax upon the great pectoral muscles be- tween the arm-pits and the sternum, and intended, in the female, for the secretion of milk. They are he- mispherical in their mechanical shape, and vary very much in size according to the age of the person and the state of the uterine system. The skin which covers the mamma is very fine and thin, and through it may be seen readily the veins FEMALE MAMMAE. 311 which creep beneath it. It is very extensible, but does not possess much power of contraction. Be- neath the skin, between it and the surface of the gland, there is an abundance of cellular substance in- termixed with lobules of fat, which together make a greater volume of matter than the gland itself. The exterior surface of the gland is rendered very unequal by being penetrated at different depths by this cellu- lar and adipose matter, and its lobules are divided by irregular fossae from each other. The substance of the gland is united to the pectoralis major muscle by a loose cellular tissue which contains very little fat. The mamma is composed of lobes of different sizes united together in such a way by cellular texture that they cannot be separated without injury to them. These lobes are composed of Lobuli, which again are formed by granuli of a white colour tinged with red. These granuli are the size of a millet-seed, and, ac- cording to some anatomists, consist of vesicles which are very apparent in a gland filled with milk, by the aid of a microscope.* The roots of the excretory vessels, or the lactife- rous ducts, arise from these grains; they are ex- tremely fine, and unite, after a short course, to con- tiguous ones by successive accumulations resembling the branches of a tree; large trunks are finally form- ed which terminate each in its respective sinus placed * See Marjolin. vol. ii. p. 295 312 OF THE TRUNK. in the centre of the gland at the base of the nipple. There are about fifteen lactiferous ducts in all, which converge from the circumference of the gland to its centre; their course, however, is very tortuous and their coats are thin, semitransparent, and very capa- ble of extension and contraction. The sinuses in which the lactiferous tubes terminate are of different diameters; the largest are about three lines wide, but others scarcely exceed the diameter of the lactiferous tubes. From the external extremity of each sinus arises the excretory duct which conducts the milk to the surface of the nipple. This excretory duct is of a conical shape, sometimes dilated in its middle, and is curved and folded upon itself when the nipple is not in a state of erection, by which means the milk is prevented from flowing through it. The sinuses and the excretory ducts are united to each other by condensed cellular membrane; they have no valves, neither have they lactiferous tubes in any part of their course. An opinion was entertained by Haller, and by many other anatomists after him, that some of the lactiferous ducts originated in the surrounding cellu- lar texture; this has been refuted by the researches of Cuboli. The excretory ducts of the different lobes are kept distinct from each other, there being no anastomoses between them; hence it happens that in the injection of the gland with mercury it is neces- sary to inject each lactiferous tube separately. Some FEMALE MAMMJE. 318 anatomists have thought that there is a direct com- munication between the roots of the lactiferous tubes and the arteries, veins and lymphatics. Mascagni, after a very successful injection of the gland in which he filled its vesicles with quicksilver, not meeting with such an occurrence, was induced to think that when such communication did happen it was by rupture. The Areola is a rose-coloured circle in virgins which surrounds the base of the papilla or nipple. In women who have borne children or in those whose age is advanced it becomes of a dark brown. The skin of the areola is extremely delicate, and on its surface, particularly in pregnant or nursing females, there are from four to ten tubercles which sometimes form a regular circle near its circumference, and in other subjects are irregularly distributed. Each of these tubercles has, near its summit, three or four foramina, which are the orifices of the excretory ducts, of a little gland forming the tubercle. From this gland is se- creted an unctuous fluid for protecting the surface of the areola. The areola consists of a spongy tissue beneath which there is no fat; it is susceptible of dis- tention during lactation or from particular excite- ment. The Papilla is a truncated cone in the centre of the mamma, of the same colour with the areola and surrounded by it. The lactiferous ducts terminate r r 314 OF THE TRUNK. on its extremity. It is collapsed and in a very pli- able state for the most part, but when excited it swells, becomes more prominent and of a deeper co- lour. Its skin is rough and provided with numerous and very small papillae. Its internal structure con- sists of the lactiferous ducts united by condensed cel- lular membrane. The mamma is supplied with blood from the tho- racic, axillary, intercostal, and internal mammary ar- teries. Its veins attend their respective arteries. The nerves come from the brachial plexus and the intercostals. Its lymphatics run into the internal mammary and axillary trunks. PART II. CHAPTER V. Of the Nerves and Vessels of the Trunk. I have thought it better to give a separate consi- deration to the nerves and vessels of the trunk, not involving them with the viscera; because it is the easi- est manner of studying them, and such as young men most frequently adopt when left to their own discre- tion, which alone is in some measure a proof of its being the most natural and agreeable method. The arteries should be filled with either of the coarse in- jections; it is less important for the veins, and may be dispensed with. Section I. of the nerves. The Phrenic Nerve passes into the thorax from the neck, by the side of the descending cava on the right, between it and the pleura, it then continues on 316 OF THE TRUNK. the side of the pericardium in a direction almost straight to the diaphragm, going before the root of the lungs. On the left side, with the exception of the descending cava and of its being turned somewhat out of its way by the projection of the point of the heart, its course is the same.* The nerve getting to the diaphragm is spread out in a radiated direction on its muscular wing, both on its upper and lower surface. Anatomists of sufficient respectability report branches from the sympathetic mounting up to the diaphragm, and having their ter- minating ramifications united with those of the phre- nic. Portions of the renal plexus of nerves, are also said to be bestowed on the diaphragm. The Par Vagum, before it gives off the recurrent nerve, sends off one or more twigs to join the car- diac plexus, it also contributes to the same when the recurrent nerve is separating from it. From a little below this place the par vagum sends off the Anterior Pulmonary Plexus, derived principally from two branches, a large and a small one, which subdivide and ga in front of the trachea and of the root of the lungs. The ramifications of this plexus follow gene- rally the bronchium and blood-vessels into the sub- stance of the lungs, but some of them are turned into the cardiac plexus. * For a further account of this nerve see the Neok NERVES. 317 The trunk of the par vagum proceeds on the out- side of the bronchium and a little lower down, behind it, then passes in contact with the posterior surface of the root of the lungs. Here it gives off succes- sively five or six branches of different magnitudes which leave the main trunk almost at right angles, divide and subdivide, and following the bronchium, are spent upon its ultimate ramifications in the lungs. These branches constitute the Posterior Pulmonary Plexus. After the posterior pulmonary plexus is given off, the par vagum remaining still considerable, betakes itself to the oesophagus, being split into three or four fasciculi which spread out and unite again. From the crossing of the bronchium to the joining with the oesophagus a great many small ramifications are sent to the oesophagus forming a plexus on it, some are sent also to the aorta. The Left Par Vagum is situated on the anterior lateral surface of the oesophagus, and the Right Par Vagum on the posterior lateral surface, each however adhering to its own side, and forming a plexus which partially surrounds the oesophagus. They pass through the foramen of the diaphragm, along with the oesophagus, and their fibres are reassembled into more considerable trunks. The left par vagum is dis- tributed along the lesser curvature of the stomach, between the cardia and pylorus, to the anterior side of the stomach, to the lesser omentum, and some of its 318 OF THE TRUNK. branches extend to the left hepatic and solar plexus. The right par vagum surrounds with its branches the cardiac orifice of the stomach, supplies the under side and great curvature, sends branches along the coro- nary artery to unite to the hepatic and splenic plex- uses, and one trunk to the solar plexus The Sympathetic or Intercostal Nerve, is principally employed in the thorax in supplying the heart. With this view it sends to it three nerves on the right side, and two on the left called Cardiac. The Right Superior Cardiac is derived by several filaments from the upper cervical ganglion, joined by some from the superior laryngeal nerve. They unite into one trunk, which accompanies the common carotid on its external surface as far as the middle cervical ganglion; here the trunk divides, one part of it and the smaller running along the carotid and arteria in- nominata to the aorta, the other joining a plexus just below the middle cervical ganglion. The Middle or Great Cardiac Nerve arises from the inferior part of the middle cervical ganglion, passes along the external surface of the carotid artery, and crosses the subclavian in front just at its root, it then goes along with the arteria innominata for a little distance, and terminates in the upper part of the cardiac plexus. The Third or Small Cardiac Nerve comes from the lower cervical ganglion by several filaments which NERVES. 319 unite into a smaller number forming a plexus, which descends behind the subclavian artery and between the innominata and trachea to the posterior part of the arch of the aorta. On the left side the Upper Cardiac nerve originates in the same way as on the right, from the first cervi- cal ganglion and upper laryngeal; attending the com- mon carotid, it is increased by fibrillae from the sym- pathetic between the first and second ganglions. In the upper part of the thorax this nerve is between the carotid and subclavian arteries, and at their roots some of its branches go in front of the aorta and others behind it. The second cardiac nerve of the left side, is derived from the middle and lower cervical ganglions of the sympathetic. Several branches being dispatched by the two ganglions, they form a plexus which surrounds the subclavian at the origin of the inferior thyroid and transversalis colli arteries. From this plexus-several cords proceed longi- tudinally behind and before the subclavian artery to the aorta, and here being joined to branches from the upper cardiac nerve, they form a plexus on the anterior and posterior faces of the aorta. The Cardiac Plexus consists of a very considera- ble number of nervous filaments formed by the com- bination of the cardiac nerves on both sides with branches sent off from the recurrent nerves and the par vagum. It is placed between the aorta and the 320 OF THE TRUNK. trachea and bronchia, and extends from the lower cer- vical ganglion to the top of. the base of the heart where the aorta and pulmonary artery come out. It is fixed in loose cellular and adipose membrane at its upper part; below its meshes are much involved with the glands about the bifurcation of the trachea, and on the aorta its branches lie very close to this vessel, being bound to it by the internal lamina of the pericardium. Several branches of the plexus wind over to the front of the aorta and pulmonary artery, where they are also confined closely to these vessels by the inter- nal lamina of the pericardium, and seen to enter into their structure. The cardiac plexus, penetrating from the base of the heart to the root of the aorta, is diffus- ed through themuscular structure of the former, its trunks following the courses of the coronary arteries. The Sympathetic Nerve, from the last cervical gan- glion, proceeds over the head of the first rib and de- scends through the thorax in contact with the heads of all the ribs and exterior to the pleura. At the up- per edge of the head of each rib it forms a ganglion which unites with the intercostal nerve behind it by two branches. At the lower part of the thorax it pe- netrates into the abdomen beneath the crus of the diaphragm; it then proceeds forwards and downwards on the spine between the tendinous crus of the dia- phragm and the psoas magnus muscle, and lies on NERVES. 321 the sides of the bodies of the lumbar vertebrae, being near the vena cava on the right side and the aorta on the left. About the middle of the body of each lum- bar vertebra it forms a ganglion which dismisses one or two nervous filaments to the corresponding lum- bar nerve, which filaments pass between the bone and the psoas muscle. From the loins, the sympathetic descends into the pelvis on the inner side of the fora- mina of the sacrum; here also it forms a ganglion cor- responding with each sacral nerve, and detaches a filament to join it. Finally the sympathetic termi- nates on the os coccygis where the ultimate branches of the opposite sides unite. From several of the upper ganglions of the sympa- thetic in the thorax, fibrillae depart which join the posterior pulmonary plexus, and also are distributed in the form of a plexus on the aorta. From the fifth, sixth, seventh, eighth, ninth, and tenth thoracic gan- glions branches are sent off which, descending ob- liquely on the sides of the vertebrae, unite succes- sively so as to form a considerable trunk, the Great Splanchnic Nerve, which gets into the abdomen through the foramen in the diaphragm for the aorta. From the tenth, eleventh, and twelfth dorsal gan- glions filaments are, in like manner, successively sent off which form one or two trunks that penetrate into the abdomen through the crus of the diaphragm; this constitutes the Lesser Splanchnic Nerve, which, in s s 322 ®F THE TRUNK. part, unites to the great splanchnic nerve, and the re- mainder goes to the renal plexus. The Great Splanchnic Nerve, having entered the abdomen, is associated with the semilunar ganglion. This ganglion is situated on the crus of the diaphragm and on the sides of the coeliac and superior mesen- teric arteries. It is formed rather by a congeries of small ganglions arranged in a lunated form than by a single one. These small ganglions are united by a reticular work of nerves, and from them proceeds a very intricate and combined net-work of nervous fibres called the Solar Plexus. The Solar Plexus is behind the stomach and above the pancreas, and surrounds, with its branches, the coeliac and superior mesenteric arteries. It is form- ed from the semilunar ganglions of both sides, and to their ramifications are added some from the par va- gum and phrenic nerves. That portion of the solar plexus on the coeliac artery assuming its name dis- misses ramifications in the course of the gastric, he- patic, and splenic arteries to the viscera supplied by them, as the stomach, liver, pancreas, and spleen. The Superior Mesenteric Artery has around it the Superior Mesenteric Plexus, which accompanies the arterial branches to the right side of the colon, to its transverse portion, and to all the small intestines NERVES. 323 From the inferior part of this plexus proceeds a de- tachment in front of the aorta to the inferior mesen- teric artery which supplies the left side of the colon and the rectum. From the lower part of the solar plexus arises the Renal Plexus, which surrounds the emulgent artery and is distributed to the kidney and to the capsula renalis. The renal plexus detaches near the kidney a few fibres, which, being joined by others from the first or second lumbar nerves, accompany the sper- matic artery, and are therefore called the Spermatic Plexus. In the male they are distributed on the cord and testis, and in the female on the ovarium and fal- lopian tube. From the lower part of the renal and solar plexuses there proceeds a reticulated structure of nerves in front of the aorta as low down as its bifurcation. This is joined by fibres on each side from the sym- pathetic of the loins. It divides and, following the course of the hypogastric artery on each side, is dis tributed to the bladder, rectum, and vesiculae semi- nales of the male, and to the uterus, vagina, bladder, and rectum of females. This is the Hypogastric Plexus, which is further increased by filaments from the sacral parts of the sympathetic. The other nerves of the trunk consist of the Dor- 324 OF THE TRUNK. sal, the Lumbar, and the Sacral. Each arises as a solitary trunk from its appropriate spinal ganglion, which very soon divides into anterior and posterior fasciculi. The posterior is distributed to the mus- cles of the back, but the anterior has a destination not so uniform. The anterior branches of the Dorsal nerves are all connected to the ganglions of the sympathetic, and, running between the internal and external intercostal muscles, are distributed to the parietes of the thorax and abdomen. The first dorsal nerve joins the axil- lary plexus also. The second sends a branch through the external intercostal muscle to the axilla which joins with a branch of the internal cutaneous nerve of the arm, and is supposed, as it also sends a filament to the lower cervical ganglion of the sympathetic, to establish the sympathy between the arm and the heart in angina pectoris. The third dorsal also sends a branch to the axilla. The upper lumbar nerves are employed upon the integuments of the abdomen and in the formation of the lumbar plexus which supplies the front of the thigh and leg. The lower lumbar nerves and the sa- cral form the sciatic plexus, which supplies the poste- rior parts of the lower extremity. The further consideration of the spinal nerves is referred to the Anatomy of the Limbs. BLOOD-VESSELS. 325 Section II. OF THE BLOOD-VESSELS OF THE TRUNK. The course of the aorta, from its origin to its pas- sage through the diaphragm, has already been men- tioned, (see Thorax;) as well as that a line to subtend the base of its curvature must be drawn from the ster- nal extremity of the third rib on the right, to the dor- sal extremity of the third rib on the left side. The first branches given off after the coronary arteries are the Arteria Innominata, the Left Carotid, and the Left Subclavian. The Arteria Innominata is in ad- vance of the others, and divides, after an inch and a quarter of length, into right carotid and subclavian. For an exposition of the course of the Carotids see the article Neck. The Subclavian Artery, before it passes between the scaleni muscles, sends off five branches: the Infe- rior Thyroid, the Vertebral, and the Transverse Ar- tery of the neck have been mentioned in the article Neck; the other two belong to the trunk. The first is the Arteria Mammaria Interna, which comes from the subclavian commonly before any of the others; and the second is the Superior Intercostal Artery. about the last of the cluster. The Internal Mammary Artery, after its origin, de- 326 OF THE TRUNK. scends immediately and fixes itself between the pleura and the cartilages of the true ribs about three-fourths of an inch from the outer edge of the sternum; it gets into the abdomen"and is distributed finally to the rec- tus muscle, anastomosing in it with the epigastric ar- tery. It sends a branch which attends the phrenic nerve on the side of the pericardium; it supplies the intercostal muscles, anastomoses with the intercostal arteries, and sends some branches to the mamma. The Superior Intercostal Artery runs across the heads of the first and second ribs, and supplies the inV tercostal spaces corresponding to them; it also, some- times, supplies the third intercostal space. Below its curvature, in the thorax, the aorta gives off the (Esophageal, the Bronchial, and the Intercos- tal Arteries. The Bronchial Arteries are vessels intended for the nourishment of the lungs; the right comes from the superior intercostal artery, and the left from the aorta; this arrangement is not uniform, for sometimes both come from the aorta. The (Esophageal Arteries are five or six in num- ' ber, and are spent upon the oesophagus, as their name implies; the lowermost descends to the stomach. The Aortic Intercostals supply, commonly, the ten inferior intercostal spaces. The upper ones have to BLOOD-VESSELS. 327 rise somewhat obliquely to get to their destination, whereas the lower ones pass nearly horizontally. The right are longer than the left, and the oesophagus is in front of them. Each one joins the rib near its tu- bercle, and keeps at its lower edge between the inter- nal and external intercostal muscles in the groove of the bone. The first branch is the dorsal, given off near the spine, which passes to the muscles of the back, and dispatches an arteriole through the inter- vertebral foramen to the medulla spinalis. When the intercostal arrives near the middle of the rib it sends off a branch which passes near the upper edge of the lower rib; and when it has got two-thirds the length of the rib it leaves its lower edge to be distributed to the intercostal space and contiguous parts. The Abdominal Aorta passes almost in front of the vertebrae, being pushed but very little to the left of the median line. It gives off several large branches to the viscera, and at the intervertebral space of the fourth and fifth vertebrae of the loins it divides into the two Primitive Iliacs. The Phrenic Arteries come from the aorta imme- diately on the latter emerging from between the crura f of the diaphragm. They are two in number, and named from their situations, Right and Left; they ra- mify on the concave surface of the diaphragm. Their origin is subject to variations. The Coeliac Artery is immediately below the phre- 328 OF THE TRUNK. nic; it is a large vessel about half an inch long stand- ing from the aorta at right angles, and divides into the Hepatic, Gastric or Coronary, and Splenic Arte- ries. The Arteria Hepatica goes to the liver through the capsule of Glisson, and is distributed through this vis- cus. Near the liver it sends off the Arteria Gastrica Dextra, which is distributed to the great curvature of the stomach and the contiguous parts. The Arteria Gastrica is between the other two; it joins the stomach near the cardia and proceeds along the lessure curvature to the pylorus, supplying conti- guous parts. The Arteria Splenica is the largest of the three. It goes tortuously along the upper edge of the pan- creas to the spleen; in its course it sends to the sto- mach the Gastrica Inferior Sinistra, which is spent on its greater extremity and the left side of the greater curvature. From this vessel also are deriv- ed the Vasa Brevia of the stomach and the Arteries of the Pancreas. The Arteria Mesenterica Superior is about half an inch below the coeliac, and is nearly of the same size; it passes downwards under the pancreas and above the duodenum, supplying all the small intestines, the right side of the colon, and its transverse arch. It has a great many anastomoses in it constituted by a series of arcades, one upon the other, diminishing in BLOOD-VESSELS, 329 size as they approach the intestine. That portion of the artery which supplies the junction of the ileum with the colon is called Arteria Ileo-Colica; that which supplies the right side of the great intestine is the Arteria Colica Dextra; and that which supplies the arch of the colon is the Colica Media. The Emulgent Arteries are two in number, one from each side of the aorta coming off at right angles from it, and not much inferior in size to the mesen- teric. The right is the longest and passes behind the ascending vena cava. They go to the kidneys and to the capsulae renales. The arterial distribution from the aorta here is subject to variations, the arte- ries of the capsulae renales coming sometimes from the aorta, and on other occasions from the emulgents. There are also several arteries going to the adipose matter in which the kidneys are placed equally un- settled in their origin. The Spermatic Arteries arise immediately below the emulgents one on each side, they are about the size of a crow-quill, and are remarkable for their length; sometimes the left arises from the emulgent of that side. They pass downwards to the testicles behind the peritoneum and before the psoas muscles, not far from the ureters, spermatic plexuses of nerves, and spermatic veins. At the internal abdominal ring they meet with the vasa deferentia, and constituting a t t 330 OF THE TRUNK. part of the spermatic cords, are distributed on the testi- cles in the manner expressed in the account o! these organs. In the female these arteries go to the ovaria, fallopian tubes, and uterus. The Arteria Mesenterica Inferior arises below the spermatics; it is much smaller than the superior. Three branches proceed from it called the Left Colic Arteries, from their distribution to the left side of the colon, and are distinguished from each other by the terms Superior, Middle, and Inferior. The superior anastomoses with the colica media, forming with it the great Mesocolic Arch- The others supply the sigmoid fleslihre of the colon and the part just above it. A branch is continued from the inferior me- senteric to the rectum, constituting the superior he- morrhoidal artery. From the centre of the fork formed by the bifur- cation of the aorta, there proceeds a small arterial tube about the size of a crow-quill called the Arteria Sacra Media, from its running down to the os coc- cygis just over the middle line of the sacrwm. It sends branches on each side towards the foramina in the sacrum. The Arteriae Lumbales are five in number on each side; they pass off at right angles from the aorta over the sides of the lumbar vertebrae, some of their BLOOD-VESSELS. 331 branches penetrate the intervertebral foramina to get to the medulla spinalis, others pass to the muscles of the back. Besides which the lower parts of the pa- rietes of the abdomen are supplied by them. They inosculate with the circumflexa ilii, with the epigas- tric and with the internal mammary arteries. The Primitive Iliacs, (Iliacae Communes,) one on each side, are formed by the termination of the abdo- minal aorta; they extend from the fourth lumbar ver- tebra to the sacro-iliac junction, opposite to which they divide into two trunks, the External Iliac Artery and the Hypogastric. In this course they give off no collateral branch of any consequence, and are crossed by the ureters. The Hypogastric or Internal Iliac, (Iliaca Interna or Ramus Hypogastrics,) gives off several branches the origins of which vary considerably, the main trunk itself is therefore of various lengths. It is dis- tributed to the viscera of the pelvis and to the mus- cles on its external surface. 1. The Ileo Lumbalis is commonly the first branch of the hypogastric. Arising from its posterior exter- nal part it passes outwardly between the psoas mag- nus and iliacus internus muscles, and divides into two branches, one of which is distributed to the loins, and the other upon the iliacus internus muscle. 2. The Arteriae Sacrae Laterales come next, aris- 332 OF THE TRUNK. ing by one or more trunks from the hypogastric or one of its large branches; they commonly equal in number the foramina of the sacrum, and passing into them are distributed upon the inferior part of the me- dulla spinalis anastomosing with the middle sacral artery. 3. The Obturator Artery, (Arteria Obturatoria,) comes from the front of the hypogastric, it passes along parallel with the brim of the pelvis, and going through the obturator foramen is distributed to the hip joint and to the muscles on the upper internal part of the thigh. Its origin is occasionally from the epigastric. 4. The Middle Hemorrhoidal, (Hemorrhoidea Media,) comes sometimes from the gluteal, &c. It is thus named from its relative position to the upper and lower hemorrhoidal on the rectum. Besides going to this organ it supplies the prostate gland and the vesiculae seminales of the male, and the vagina and bladder in females. 5. The Uterine Artery, (Art Uterina,) is peculiar to females, and gets to the uterus between the lamina? of the broad ligaments. 6. The Vesical Arteries, (Arteriae Vesicales,) are derived from what was the umbilical artery of the foetus, and are distributed to the bladder. The hypogastric artery terminates below in two large branches, the Gluteal and the Ischiatic. The Gluteal Artery, (Arteria Glutaea,) passes out of the pelvis at the upper part of the ischiatic foramen BLOOD-VESSELS. 333 above the pyriformis muscle, it is situated in contact with the edge of the bone, and its trunk is accessible from the external parts of the pelvis. Having got to its outside, the trunk of the gluteal divides immedi- ately into two branches which pass forwards towards the anterior margin of the pelvis, one of them rami- fying between the gluteus minimus and medius, and the other between the medius and maximus. The Ischiatic Artery, (Arteria Ischiadica,) coming from the inferior part of the hypogastric, is situated before the belly of the pyriformis muscle, and issues from the pelvis below its inferior edge and in front of the sciatic nerve. It pursues its course downwards on the back part of the thigh between the trochanter major and the tuberosity of the ischium, being then at the internal edge of the sciatic nerve. In the pel- vis it sends off the Internal Pudic, and on the outside of it, is distributed to the inferior edge of the gluteus maximus and to the muscular structure near the sa- crum and coccyx; also to the muscles on the back and upper parts of the thigh. The Internal Pudic, (Arteria Pudica Interna,) di- verging from the ischiatic, passes between the two sacro-sciatic ligaments to the inner side of the tube- rosity of the ischium, and continues on the inner side of the rami of the ischium and pubis towards the sym- physis. In this course it gives off several branches 334 * OF THE TRUNK. in the following order: to the lower part of the rec- tum and to the sphincter ani muscle, the Lower He- morrhoidal Artery; to the back part of the scrotum, between the transversus perinei muscle and the skin originating near the muscle and passing in its direc- tion, the Perineal Artery. Upon the arrival of the internal pudic near the penis it detaches to this body a branch which penetrates and ramifies minutely through the structure of the corpus spongiosum urethrae. At the symphysis of the pubis it sends off a branch which gets to the dorsum of the penis and extends longitudinally as far as the glans, being dis- tributed to the elastic ligament, to the integuments, and to the prepuce; this is the Superficialis Dorsi Penis. Finally, the terminating branch of the internal pudic penetrates into the corpus cavernosum, passes straight forwards, and is distributed, by very minute branches, to its cells, some of which go to the other side. The External Iliac Artery, (Iliaca Externa,) seems to be the continuation of the common iliac; it passes along the brim of the pelvis on the inner side of the psoas magnus muscle to Poupart's Ligament. Here it is in front of the junction of the psoas magnus and iliacus internus muscles about half way between the symphysis of the pubis and the anterior superior spi- nous process of the ileum, having the anterior crural nerve on its outside and the internal iliac vein on its BLOOD-VESSELS. 335 inside. It gives off no branches till it reaches Pou- part's ligament, when the Epigastric arises from it. The Arteria Epigastrica at first passes downwards and inwards; it then rises upwards obliquely till it reaches the exterior edge of the rectus muscle. Con- tinuing afterwards to ascend, it is spent upon the an- terior parietes of the abdomen by many branches, some of which inosculate with the internal mammary. The Circumflex Artery, (Arteria Circumflexa Ilei,) arises from the external iliac opposite to the epigas- tric. It runs along the posterior edge of Poupart's ligament to the spinous process of the ilium; thence it continues its course near the internal margin of the crista, being distributed to the iliacus internus mus- cle. A branch of it, near the spinous process, rises upwards and is spent upon the abdominal muscles. • It anastomoses with the arteria ileo lumbalis. VEINS OF THE TRUNK. The Superior Cava, (Cava Descendens,) is suffici- ently alluded to in the description of the thorax, to render a minute notice of it here unnecessary. It receives the blood from the left arm and side of the head by a trunk common to the two, which crosses the sternum obliquely a little below its superior edge. This venous trunk and the one belonging to the right arm and the right side of the head constitute the De- scending Cava, properly speaking. 336 OF THE TRUNK. On a horizontal line with the upper edge of the root of the right lung is the point where the descend- ing cava is joined by the vena azygos. The latter is formed by the union, into one trunk successively, of the ten inferior intercostal veins of the right side. About the sixth dorsal vertebra this trunk is joined by one formed by the successive union of the six in- ferior intercostal veins of the left side. The trunk of the vena azygos, as stated, is on the right side of the posterior mediastinum, and forms a regular and beau- tiful arch over the root of the right lung. The Superior Intercostal Veins of the left dis- charge into the subclavian vein by a common trunk; the two superior of the right side into the descending cava. The Internal Mammary Vein has nothing very pe- culiar; it observes the course of its artery, and empties into the subclavian vein near its origin. The Cava Ascendens is formed, in the lower part of the trunk, by the union of the external and internal iliac veins, into the common iliacs and the subsequent junction of the latter at the fourth dorsal vertebra. This vein ascends on the right of the aorta, receives many accessions in its course, penetrates the right opening of the diaphragm, and terminates in the right auricle. Each artery of the pelvis has its corresponding BLOOD-VESSELS. 337 vein; it is therefore unnecessary to describe the latter, except in regard to peculiarities. About the neck of the bladder, vesiculae seminales, and the base of the prostate there is a considerable accumulation of veins forming a very vascular plexus of them; they come originally from the vena ipsius penis and from the proper vesical veins. The several veins of the pelvis derived from the ischiatic, gluteal, and internal pudic arteries, &c. ac- cumulate at the sacro-iliac junction into one trunk, which ascends by the side of the hypogastric artery and joins the external iliac vein. The Ascending Cava is joined, at its fork, by the middle sacral vein, and above it by the lumbar veins on each side. The right spermatic vein discharges into the ascending cava, but the left into the emul- gent of that side. The emulgent and capsular veins correspond with the arteries, the right being shorter than the left, from the position of the vena cava. The left emulgent vein is in front of the aorta. The ascending cava is next joined by the hepatic veins which have been mentioned, and lastly by the phrenic. The Venous Trunks, derived from the superior and inferior mesenteric arteries and from those of the coeliac which do not go to the liver, as the splenic and gastric, form the large trunk of the vena porta- u u 338 OF THE TRUNK. rum, the history of which is given in the account of the liver. Section III. THE THORACIC DUCT, (VAS CHYLIFERUS.) The common trunk of the absorbent system com- mences most commonly at the second or third lum- bar vertebra, in front of its body, by the union of the absorbent vessels of the lower extremities, pelvis, and intestines. This vessel, immediately after its forma- tion, is subjected to a dilation of various shapes and lengths called the Receptaculum Chyli; after which it proceeds regularly upwards in front of the vertebrae, between the vena azygos and the aorta, to the upper part of the thorax. It passes between the crura of the diaphragm and, for some part of its course, is immediately behind the oesophagus. At the fourth dorsal vertebra it begins to incline to the left, and, preserving that direction, it gets into the neck as high as the upper edge of the seventh cervical vertebra and just to its left side. Here it forms an arch which descends forwards and outwards in front of the sub- clavian artery and between the internal jugular vein and the scalenus anticus muscle, and there terminates, by an orifice protected by two valves, in the fork form- THORACIC DUCT. 339 ed by the junction of the left internal jugular and sub- clavian veins. Several interesting varieties occur in the vas chy- liferus; sometimes two trunks are formed originally on the lumbar vertebrae which run parallel with each other, and there unite at the lower dorsal vertebrae. The thoracic portion of the duct varies in size and con- tinuity, being divided, once or oftener, into two trunks which unite again, and being also contracted at par- ticular points. The cervical or terminating portion of the duct is occasionally divided into two tubes, which have separate orifices. There is a very good plate in Caldani representing the terminations of the several lymphatic trunks in the region of the neck; in this plate the thoracic duct empties, after a considerable dilatation, into the inter- nal jugular vein about an inch above its junction with the subclavian; and the lymphatics of the left side of the head and neck form two trunks which discharge separately into the convex side of the Thoracic duct. The lymphatics of the left upper extremity form a trunk whose orifice is in the subclavian vein about an inch below its junction with the internal jugular. The lymphatics of the right arm, lung, right side of the neck and head converge, by four trunks, towards the junction of the right subclavian and internal jugu- lar, and then unite into one, which discharges itself at the posterior face of this junction. The venous ori- fice of each of these lymphatic vessels is secured from a regurgitation of blood by one or more valves^ PART 11. CHAPTER VI. Of the Muscles of the Back Make an incision through the integuments from the lower part of the occiput to the os coccygis, di- rectly over the spinous processes of the vertebrae. Make a second incision from the lobe of the ear to the acromion process. Unite the upper ends of these incisions. Make a third cut through the integu- ments from the acromion process to the posterior fold of the arm-pit, extend the latter downwards to the middle of the crista of the ilium, in a direction some- what curved, the convexity of the line being back- wards. Lastly, make a cut horizontally from the acromion process to the spine. Begin the dissection at the last cut, and raise the upper and then the lower flap in the direction of the muscular fibres as they make their appearance. In this manner is exposed the two superficial broad muscles of the back, the Trapezius and the Latissimus Dorsi. MUSCLES OF THE BACK. 341 The Trapezius is a beautiful broad muscle imme- diately under the skin, covering the back parts of the neck and thorax, extending from the bottom of the latter to the top of the former. Its anterior edge above is parallel with the posterior edge of the sterno cleido mastoideus. Its posterior edge is joined with that of its fellow, and below it overlaps the latissimus dorsi in part. It arises from the occipital protuberance and from eight or ten lines, sometimes more, of the upper transverse ridge of the occiput, by a tendinous mem- brane. From the five superior spinous processes of the neck through the intervention of the Ligamentum Nuchae, tendinous from the two lower spinous processes of the neck, and from all of the back. It is inserted fleshy into the external third of the clavicle, tendinous and fleshy into the acromion pro- cess, and into all the spine of the scapula. Its fibres having a very extended origin must of course con- verge in getting to these insertions; the upper fibres descend, the lower ascend, and the middle are hori- zontal. It draws the scapula towards the spine. In the cervical portion of these muscles, formed by the ori- gins of both muscles united, is an elliptical expanse of tendon lying over the ligamentum nuchae and ex- tended on each side. The ligamentum nuchae itself is a vertical septum of ligamentous matter extending 542 OF THE TRUNK. from the central line of the occipital bone, to the spi- nous processes of all the vertebrae of the neck. At its upper part where the spinous processes of the neck are short, this membrane is very broad, and di- vides completely the muscles of the two sides of the neck from each other. The Latissimus Dorsi is situated under the skin at the lower part of the back, so as to cover its whole posterior portion. It arises by a thin tendinous ex- panse from the seven inferior spinous processes of the back, and by a thick tendinous membrane from all the spines of the loins and sacrum. This mem- brane is the fascia lumborum, is common to several of the muscles which have their origin in this region, and extends along the iliac margin of the sacrum, so as to arise also from the posterior third of the spine of the ilium.* Besides these origins the latissimus dorsi has four fleshy heads from the sides of the four inferior false ribs, which are interlocked with the four inferior heads of the obliquus externus abdominis. From this extended origin the fibres converge so as to form the fold of the axilla and terminate in a flat thick tendon of two inches in breadth, which is in- serted into the postertor ridge of the groove of the os humeri. The upper part of this muscle passes * This origin frequently is tendinous at the back part of the ilium, and fleshy in front. MUSCLES OF THE BACK. 343 over the inferior angle of the scapula and derives a fasciculus of fibres from it. It draws the os humeri downwards and backwards. Detach now the trapezius from its origin and turn it over the shoulder. Begin also to detach the latissi- mus dorsi from its origin above, turning downwards the upper edge of the muscle as the separation goes on. By doing so in a little time is brought into view the upper edge of the Serratus Inferior Posticus. The origin of this muscle is inseparably united to that of the latissimus dorsi. therefore to view it properly let the fleshy part of the latissimus be detached from the fascia lumborum. We shall then see that the serra- tus arises by a tendinous membrane from the two in- ferior spines of the back, and the three superior of the loins. It is inserted by fleshy digitations into the under edge of the four inferior ribs. It draws the ribs downwards, and is an antagonist to the diaphragm in some respects, but more particu- larly to the serratus superior posticus. The removal of the trapezius above, brings into view several muscles, the most superficial of which are the rhomboid, there being two together looking very much like one. The Rhomboideus Minor is above. It is a nar- 344 OF THE TRUNK. row muscle which arises by a thin tendon from the three inferior spines of the neck, and passing obliquely downwards, is inserted into the base of the scapula opposite the origin of its spine. The Rhomboideus Major arises also by a thin tendon from the last spine of the neck and from the four superior of the back, and is inserted into all the base of the scapula below its spine. These muscles draw the scapula upwards and back wards. Detach them from their origins, which shows next, The Serratus Superior Posticus, arising by a thin tendon from the three inferior spines of the neck and the two superior of the back, and inserted into the second, third, fourth and fifth ribs by tendinous and fleshy slips, a little beyond their angles. This muscle draws the ribs upwards. A good view of the serratus major anticus where it is inserted into the base of the scapula, and of its situation between the thorax and scapula, is obtajned at this stage of the dissection. The muscle itself, in consequence of aris- ing on the anterior lateral parts of the thorax, has been considered in the remarks preliminary to the study of that cavity. The Levator Scapulje is placed between the MUSCLES OF THE BACK. 345 posterior edge of the sterno-cleido-mastoideus and the anterior, of the trapezius, its lower end is just above the Rhomboideus Minor. It arises by five rounded tendons from the five superior transverse processes of the neck, (frequently however only the three upper can be made out,) between the scaleni musdes and the splenius colli. It is inserted fleshy into that part of the base of the scapula above the origin of its spine. As its name expresses, it draws the scapula upwards. A good view of this muscle may be obtained in the front dis section of the neck. The Splenius muscle comes next; its inferior ex- tremity is under the serratus superior, but the prin- cipal part of it is covered by the trapezius. It arises from the spinous processes of tfye five inferior cervi- cal, and of the four superior dorsal vertebrae. It is inserted into the back of the mastoid process and a small part of the adjacent portion of the os oc- cipitis, and also into the transverse processes of the three superior cervical vertebrae. It is customary to consider the part which goes to the head as Splenius Capitis, and the part below as Splenius Colli; the lat- ter, in that case, is said to arise from the third and fourth dorsal vertebrae. It draws the head and neck backwards. Between the spinous processes of the vertebrae and x x 346 OF THE TRUNK. the angles of the ribs, on each side, there is a deep fossa filled up by muscles, some of them large and powerful; the most striking are the Sacro Lumbalis and the Longissimus Dorsi. The Sacro Lumbalis and Longissimus Dorsi have a common origin from the back of the pelvis and the lumbar vertebrae, and extend to the top of the thorax. They arise, tendinous externally and fleshy internally, from the posterior surface of the sacrum by its external margin and spinous processes; they arise also tendinous from the spinous processes, and fleshy from the ends of the transverse processes of all the vertebrae of the loins and from the posterior part of the spine of the ilium. From the under surface of this common belly two tendinous and fleshy heads are inserted into the inferior edge of the transverse process of each lumbar vertebra, the smaller near its root and the larger near its extremity. On a level with the lowest rib, and, indeed, somewhat below it, a fissure occurs in the muscle which divides it into the two parts. The Longissimus Dorsi is nearest the spine; it is inserted, by small double tendons proceeding from its internal surface, into the ends of the transverse pro- cesses of all the vertebrae of the back except the first. It also, from its outer edge, sends long slender ten- dons by which it is inserted into all the ribs just be- yond their tubercles, except the two inferior. MUSCLES OF THE BACK. 347 The Sacro Lumbalis is inserted into all the ribs on the spinal side of their angles by long and thin ten- dons, from its outer edge, which are longer, the higher they are inserted. By turning this muscle from the other, over towards the ribs, one may see eight slips coming from the eight lower ribs which run into the under surface of the sacro lumbalis; they are the Musculi Accessorii ad Sacro Lumbalem. These two muscles keep the spine erect and draw down the ribs. Between the ends of the spinous processes and the edge of the longissimus dorsi is a muscle almost en- tirely tendinous and scarcely to be distinguished from the latter both in consequence of its close connection with it and of its insignificant size. At its lower part it is absolutely a portion of the Longissimus, and can be separated from it only by an unnatural division. It is a mere string lying along the sides of the spinous processes, and is called from its origin and insertion the Spinalis Dorsi. The Spinalis Dorsi arises tendinous from the spi- nous processes of the two superior lumbar and of the three inferior dorsal vertebrae, and is inserted tendi- nous into the spinous processes of the nine superior dorsal vertebrae except the first. It tends to keep the spine erect. Turn now the 348 OF THE TRUNK. splenius from its insertions, wh.ch exhibits several muscles under it. The Cervicalis Descendens is a small muscle placed at the upper portion of the thorax between the insertions of the sacro lumbalis and of the longissi- mus dorsi into the upper ribs; it looks, at first, very much like a continuation or appendix of the first, run- ning to the cervical vertebrae. This muscle arises from the upper edges of the four superior ribs by long tendons; it forms a small belly which is inserted into the transverse processes of the fourth, fifth, and sixth vertebrae of the neck be- tween the levator scapulae and splenius colli by three distinct tendons. It draws the neck backwards. The Transversalis Cervicis is on the inner side of the last and in contact with it, being about the same size and having very much the same course and ap- pearance. It is considered as an appendage to the longissimus dorsi. It arises from the transverse processes of the five superior dorsal vertebrae by distinct tendons and forms a narrow fleshy belly which is inserted, by distinct tendons also, into the transverse processes of the six superior cervical vertebrae except the first. It draws the head backwards. MUSCLES OF THE BACK. 349 The Trachelo Mastoideus is at the inner side of the last muscle, in contact with it. It arises, by distinct tendinous heads, from the transverse processes of the three superior vertebrae of the back and of the five inferior of the neck, and is inserted, by a thin tendon, into the posterior edge of the mastoid process. The dorsal origins are frequently deficient or irre- gular. It draws the head backwards. The Complexus, a fine large muscle, is situated at the inner face of the trachelo mastoideus, and is readily recognized by showing itself between the bellies of the two splenii capitis, just below the occiput. A quantity of tendinous matter exists in its middle which gives it the complicated appearance, from whence its name is derived. It arises, by tendinous heads, from the seven supe- rior dorsal, and the four inferior cervical vertebrae by their transverse processes; also by a fleshy slip from the spinous process of the first dorsal. It is inserted into the inferior part of the os occipitis by the surface between the upper and lower transverse ridges, and on the outside of the vertical ridge which exists in the middle of the bone. It draws the head backwards. The Semispinals Colli is a muscle which passes obliquely from transverse to spinous processes, and is 350 OF THE TRUNK. situated between the complexus and the multifidus spinae; the course of its fibres renders it difficult to be distinguished from the latter. It arises from the transverse processes of the six upper vertebrae of the back by tendons which are in- volved with those of the adjacent muscles, and passes up to the neck to be inserted into the sides of the spi- nous processes of the five middle cervical vertebrae. It extends the neck obliquely backwards. The Semispinals Dorsi is lower down on the spine and with difficulty distinguished from the mul- tifidus, like the other passing from transverse to spi- nous processes. It lies under the longissimus dorsi, between it and the multifidus. This muscle arises by tendons, connected with those of the other muscles, from the transverse pro- cesses of the seventh, eighth, ninth, and tenth dorsal vertebrae, and passes upwards obliquely to be inserted tendinous into the sides of the spinous processes of the two lower cervical, and five upper dorsal vertebrae. It draws the spine obliquely backwards. The Multifidus Spinje lies under the muscles as yet mentioned, close to the bones of the spine; in or- der to see it well, they, therefore, should all be cut away. It has its commencement, tendinous and fleshy, on the back of the sacrum, being connected to its spi- MUSCLES OF THE BACK. 351 nous processes and posterior surface, also to the back part of the spine of the ilium. It there forms a belly of sufficient magnitude to fill up much of the cavity between the spines of the sacrum and the posterior part of the ilium. It arises also from the roots of the oblique and transverse processes of all the vertebrae of the loins, of the back, and of the four inferior of the neck. The multifidus is inserted, tendinous and fleshy, into the roots and sides of the spinous processes of all the vertebrae of the loins, of the back, and of the five inferior of the neck. This muscle consists of a great number of small bellies which are parallel to each other, arising from a transverse process and going to the spinous process either of the first or second vertebra above it. It twists the spine backwards and keeps it erect. Between the head and the first and second verte- brae, and between the two latter, there are, on each side, four small muscles intended for the motion of these parts upon each other. They are brought into view by the removal of the complexus. The Rectus Capitis Posticus Major arises ten- dinous and fleshy from the extremity of the spinous process of the dentata, and is inserted into the infe- rior transverse ridge of the os occipitis and part of the surface below it. 352 OF THE TRUNK. Its shape is pyramidal, the apex being below. It turns the head and also draws it backwards. The Rectus Capitis Posticus Minor is at the internal edge of the first. It arises tendinous from the tubercle on the back part of the first vertebra, and is inserted into the internal end of the inferior transverse ridge of the os occipitis and into part of the surface between it and the foramen magnum. It is also pyramidal with the apex downwards. It draws the head backwards. The Obliquus Capitis Superior arises from the transverse process of the first cervical vertebra, and is inserted into the inferior transverse ridge of the os occipitis behind the posterior part of the mastoid pro- cess and beneath the complexus muscle. It draws the head backwards. The Obliquus Capitis Inferior arises from the side of the spinous process of the dentata, and is in- serted into the back part of the transverse process of the first vertebra of the neck. It rotates the first vertebra on the second. The Interspinales are small short muscles placed between the spinous processes of contiguous verte- brae. In the neck they are double in consequence of its spinous processes being bifurcated: in the back MUSCLES OF THE BACK. 353 they are almost entirely tendinous; in the loins they are single and well marked. They draw the spinous processes together and keep the spine erect. The Intertransversarii are also short muscles placed in a similar manner between the transverse processes of the vertebrae. In the neck they are double, in the back they are small, tendinous, and not well expressed, and in the loins they are single and well expressed. They draw the transverse processes together, and will, of course, bend the spine to one side. The Levatores Costarum are small muscles con- cealed by the sacro lumbalis and longissimus dorsi, which pass from the transverse processes of the last cervical and the eleven superior dorsal vertebrae to the upper edges of all the ribs. They are twelve on each side of the spine, are tendinous in their origins and insertions, with intermediate muscular bellies. The upper ones are small and thin, and they in- crease in magnitude as they descend. From the infe- rior edge of nearly all these muscles a fleshy slip is detached which passes over the rib next below its ori- gin to the second rib below, and occasionally to the third. These slips are called Levatores Costarum Longiores. The others which descend from the Yy 354 OF THE TRUNK. transverse process to the rib next below are called Levatores Costarum Breviores. These muscles are parallel, in their obliquity, with the external intercostals, and are not very obviously separated from them. They perform the same ser- vice, that of elevating the ribs. The Quadratus Lumborum is an oblong muscle passing from the spine of the ilium, at its back part, by a tendinous and fleshy origin of two inches in length. It lies at the side of the lumbar vertebrae. into all the transverse processes of which it is insert- ed by short tendinous slips. It is also inserted into the lower edge of the last rib just by its head, and into the transverse process of the last vertebra of the back. It bends the loins to one side, and will draw down the last rib. This muscle is covered posteriorly by the tendinous origin of the transversalis abdominis muscle which separates it from the sacro lumbalis and longissimus dorsi. Besides the demonstration from behind, it should be viewed anteriorly in connection with the origin of the diaphragm, the psoas muscle. and the iliacus internus. PART III. OF THE EXTREMITIES AND LIGAMENTS, CHAPTER I. Of the Upper Extremity. Section I. OF the muscles. The Upper Extremity, consisting of shoulder, arm, fore-arm, and hand, has not so regular or so strong an investment of fascia as the thigh. In the shoulder and arm the membrane, corresponding with the fas- cia, is merely condensed cellular membrane which ought, in dissection, to be removed with the skin; but in the fore-arm its character is better expressed, the fascia having there a decided aponeurotic condition. The aponeurosis of the fore-arm forms a complete 356 OF THE UPPER EXTREMITIES. envelop for its muscles. It arises from the bony prominences at the elbow joint, more particularly the external and internal condyle, and the ulnar side of the tendon of the biceps muscle, the olecranon pro- cess of the ulna, and passes down to the carpus where it terminates both anteriorly and posteriorly in the annular ligament of the wrist. It is connected with the ulna along its internal margin, from the elbow joint to the wrist, and several muscles arise from its interior surface. It is unnecessary to undertake, from the first, a re- gular dissection of this fascia, inasmuch as it will be gradually exposed in proceeding with the muscles. This extremity is most conveniently studied by de- taching it from the trunk, taking care to have the clavicle with it. Section II. OF THE MUSCLES OF THE UPPER EXTREMITY. The Muscles situated on the shoulder are six in number; they extend from the scapula, for the most part, to the head and neck of the os humeri. 1. The Deltoides arises from the inferior edge MUSCLES. 357 of the whole spine of the seapula, from the margin of the acromion process, and from the exterior third of the clavicle. Its origin, for the most part, is ten- dinous and fleshy mixed, but at its posterior part it is entirely tendinous. It is inserted, by a tendinous point, into the trian- gular rough surface on the outer side of the os hu- meri near its middle. It raises the os humeri to a horizontal line with the acromion. The deltoid is situated just beneath the skin, and forms the cushion which protects and gives rotundity to the shoulder joint. Its general configuration is triangular, and, when spread out, its upper margin is much more extensive than one would suppose, being opposed to the insertion of the trapezius. Its fibres do not converge regularly to its insertion like the radii of a circle, but the whole muscle is divided into several parts; the interposition of intermuscular ten- dons into which, affecting the course of the fibres, makes several portions of the deltoid look penniform, and others like smaller deltoids introduced into the larger. The deltoid covers the insertion of the pectoralis major, latissimus dorsi, and teres major, besides that of the other muscles of the shoulder. It also con- ceals the origin of the biceps flexor cubiti and of the coraco brachialis. Its insertion is between the tri- ceps extensor and the biceps flexor, and above the origin of the brachialis internus. 358 OF THE UPPER EXTREMITIES. The deltoid should be detached from its origin and thrown down, which gives a good view of the other muscles. 2. The Supra Spinatus arises fleshy from the whole fossa supra spinata which it fills up, and from its margins. Forwards it terminates in a thick ro- bust tendon closely connected with the capsular liga- ment of the joint, which passes under the jugum formed by the articulation of the acromion with the clavicle. It is inserted tendinous into the inner face of the great tubercle of the os humeri, and will assist in rais- ing it , 3. The Infra Spinatus arises fleshy from all that portion of the dorsum scapulae below its spine, from the spine as far as the cervix, and from the several margins of the fossa infraspinata. Its fibres pass ob- liquely to a middle tendon, which adheres closely to the capsular ligament and goes under the projection of the acromion. This tendon is inserted into the middle facette of the greater tubercle of the os humeri. The infra spinatus rolls the os humeri outwards and assists in raising it. 4. The Teres Minor is situated at the inferior margin of the infraspinatus, in the fossa of the infe- MUSCLES. 359 rior costa scapulae, and looks very much like a part of the infra spinatus, to which it occasionally adheres so closely as to be separated with difficulty. It arises fleshy from the whole of the fossa, and the margins of the inferior costa, from the cervix of the bone to within an inch or so of its angle. It is inserted tendinous and fleshy into the outer face of the great tuberosity of the os humeri, just be- low the infra spinatus. It draws the humerus downwards and backwards and rotates it outwards. 5. The Teres Major is situated at the inferior edge of the teres minor. It arises fleshy from the posterior surface of the angle of the scapula and from a small part of its inferior costa; the interstice be- tween it and the teres minor is considerable. It is inserted, by a broad tendon, into the internal ridge of the groove of the os humeri along with the tendon of the latissimus dorsi. Their tendons, at first, are closely united, but afterwards there is an inter- mediate cavity lubricated with synovia. The tendon of the latissimus dorsi is anterior, and the lower edge of the teres extends further down the arm than the other. It rolls the humerus inwards and draws it down- wards and backwards. 6. The Subscapulars occupies all the thoracic 360 OF THE UPPER EXTREMITIES. surface of the scapula, being between it and the ser- ratus major anticus. It arises fleshy from the whole base, superior and inferior costa, and venter of the scapula; it is divided into several columns which look somewhat like distinct muscles, but which all termi- nate in a thick robust tendon that adheres to the in- ferior surface of the capsular ligament. This tendon is inserted into the lesser tubercle of the os humeri. The subscapularis rolls the bone in- wards and draws it downwards. The Muscles of the arm are four in number, two anteriorly and one posteriorly. 1. The Biceps Flexor Cubiti is situated imme- diately beneath the integuments, and forms the swell so obvious in the middle front part of most arms. It arises by two heads; the first called the long, is a round tendon which comes from the superior extremity of the glenoid cavity of the scapula, passes through the shoulder joint and through the groove of the os hu- meri. The second head arises tendinous from the extremity of the coracoid process of the scapula in company with the coraco-brachialis muscle. The fleshy bellies in which these tendons terminate, unite with each other a few inches below the shoulder joint to form a common muscle. At first they are only connected by loose cellular substance, but about half way down the arm they are inseparably united. MUSCLES. 3gj The biceps terminates below in a flattened oval tendon, and passes in front of the elbow joint to be inserted into the posterior rough part of the tubercle of the radius. A bursa mucosa is placed between the tendon and the front of the tubercle, the surface of the latter being covered with cartilage. From the ulnar side of this tendon proceeds a fascia running into that of the fore-arm. The relative position of the biceps is as follows: Its long head is first within the cavity of the capsular ligament, and then between the tendons of the latissi- mus dorsi and pectoralis major, where it is bound down by strong ligamentous fibres. The tendon be- low is superficial, and may be easily felt by flexing the extremity, but its insertion dips down between the pronator teres and supinator radii longus. This muscle flexes the fore-arm. 2. The Coraco Brachialis is situated at the up- per internal side of the arm at the inner edge of the short head of the biceps muscle, with which it is con- nected for three or four inches. It arises tendinous and fleshy from the middle face of the point of the coracoid process of the scapula, in common with the short head of the biceps muscle. It is inserted, tendinous and fleshy, into the inter- nal side of the middle of the os humeri, by a rough ridge, just below the tendons of the latissimus dorsi and teres major and in front of the brachialis exter- z z 362 OF THE UPPER EXTREMITIES. nus. From the lower end of this muscle proceeds an intermuscular ligament to the internal condyle of the humerus, which separates the brachialis from the third head of the triceps. This muscle draws the arm upwards and forward*. 3. The Brachialis Internus is situated immedi- ately beneath the biceps and is concealed by it, ex- cepting its outer edge. It has a bifurcated fleshy ori- gin from the middle front face of the os humeri on each side of the insertion of the deltoid, and its origin is continued fleshy from this point downwards, from the whole front of the bone to within a very small distance of its articular surface. It is inserted, by a strong short tendon, into the rough surface at the root of the coronoid process of the ulna. The brachialis flexes the fore-arm, and, by passing in front of the elbow joint, strengthens the latter very much. Its lower part lies under the tendon of the biceps and between the pronator teres and the supi- nator longus. 4. The Triceps Extensor Cubiti forms the whole of the fleshy mass on the back of the arm; it therefore occupies the space between the integuments and the bone. It arises by three heads. The first, called Longus, comes, by a flattened tendon, from a rough ridge on the inferior edge of the cervix scapu- MUSCLES. 363 8ae. The second, called the Brevis, arises, by a sharp, tendinous, and fleshy beginning, from a slight ridge on the outer back part of the os humeri just below its head. The third head, called Brachialis Exter- nus, arises, by an acute fleshy beginning, from the inner side of the os humeri near the insertion of the teres major. This muscle, both at its external and internal edge, is separated from the muscles in front of the arm by a ligamentous septum, which arises near the middle of the os humeri and runs to its con- dyles. The whole back of the os humeri, as well as the posterior surface of these intermuscular septa, is occupied by the origin of the triceps. The mus- cular fibres run in various directions according to their respective heads and places of origin. At the inferior end of the muscle is found a broad tendon which covers its posterior face. This tendon is inserted into the base or back part of the olecranon and into the ridge leading down the ulna on its ra- dial side. The triceps extends the fore-arm. Its bellies unite above the middle of the os humeri, but the interstices between them may be observed much lower down. Connected with the last is a muscle which should be dissected at the same time, as it has corresponding functions and looks very much like an appendage of the triceps j it is the 364 OF THE UPPER EXTREMITIES, Anconeus. This is a small triangular muscle just beneath the skin at the outer posterior part of the elbow joint. It arises tendinous from the posterior lower part of the external condyle of the os humeri, adheres to the capsular ligament of the joint, and is partly covered by the tendon of the triceps. It is inserted, fleshy and thin, into the ridge on the outer part of the head of the ulna leading from the olecranon, and fills up the triangular depression found there. It extends the fore-arm. Section III. OF the muscles in front of the fore-arm. The most of these muscles arise from the inner condyle of the os humeri and from the ridge leading to it, and are, either directly or indirectly, flexors of the fore-arm upon the arm. This fact should, there- fore, be impressed on the mind of the student, as it simplifies much the act of committing these muscles to heart. The systematic treatises of anatomy de- scribe the origin of each muscle as if it were totally distinct from the rest; the student will soon correct the error arising from this, and learn that the heads of all these muscles aie connected to contiguous heads muscles. 365 by adhesion and by intermuscular ligaments, and that there would be almost as much propriety in describ- ing them altogether as having a common origin, as there is in considering them so insulated. There are eight muscles situated on the front of the fore-arm, some of which are superficial and others deep-seated. 1. The Pronator Radii Teres is just beneath the fascia of the fore-arm, and forms the radial side of the muscles of the internal condyle. It arises fleshy from the anterior face of the internal condyle of the humerus, and tendinous from the coronoid process of the ulna. It passes very obliquely across the fore- arm at the internal edge of the brachialis internus muscle, and is Inserted, tendinous and fleshy, into the external back part of the radius just below the insertion of the supinator radii brevis, occupying about two inches of the middle of the bone. It rolls the hand inwards. 2. The Flexor Carpj Radialis is placed at the ulnar side of the last muscle, and is also superficial It arises, by a narrow tendon, from the lower front part of the internal condyle of the humerus, fleshy from the intermuscular ligaments, fascia, and from the upper part of the ulna. It forms a thick fleshy 366 OF THE UPPER EXTREMITIES. belly, terminating below in a tendon, which passes under the anterior annular ligament of the wrist, and runs through a groove in the os trapezium. It is inserted tendinous into the base of the meta- carpal bone of the fore-finger, in front. It bends the hand. 3. The Palmaris Longus is at the ulnar side of the flexor carpi ulnaris, and is superficial. Sometimes it does not exist. It is a small short muscle termi- nating in a long slender tendon, and arises by a small tendon from the internal condyle, and fleshy from the intermuscular ligaments on each of its sides. It is inserted, tendinous, into the humeral margin of the ligamentum annulare anterius near the root of the thumb, and a division of its tendon passes on to the aponeurosis palmaris. It bends the hand and makes tense the palmar apo neurosis. 4. The Flexor Carpi Ulnaris occupies, among the superficial muscles, the ulnar side of the fore-arm. It arises, tendinous, from the internal condyle of the humerus, fleshy from the upper internal side of the olecranon, and, by a tendinous expansion much con- nected with the fascia of the fore-arm, from the ridge at the internal side of the ulna to within three or four inches of the wrist. It is inserted into the humeral side of kthe os pisi- MUSCLES. 367 forme by a round tendon which arises high up at the radial margin of the muscle, and into which the mus- cular fibres run. Sometimes the tendon is continu- ed over the os pisiforme so as to be likewise inserted into the base of the metacarpal bone of the little fin- ger. It bends the hand. 5. The Flexor Sublimis Perforatus is conceal- ed very much by the muscles just enumerated in Con- sequence of being placed between them. To get a good view of its origin they all should be cut away from the os humeri. It arises, tendinous and fleshy, from the internal condyle of the os humeri, tendinous from the coronoid process of the ulna, and fleshy from the tubercle of the radius, the latter part of its origin being extended, tendinous obliquely, for three or four inches from that line of the radius which is at the lower margin of the pronator teres. With these ori- gins the muscle spreads over the front of the fore- arm at its upper part, from the radial to the ulnar mar- gin. Four distinct tendons pass from the lower end of the muscle, which commence much above the wrist, pass beneath its anterior ligament, and, having got to the palm of the hand, diverge to the several fingers. A tendon is appropriated to each finger which passes in front of the metacarpal bone to the phalanges, be- ing inserted, after having split into two, into the an- 368 OF THE UPPER EXTREMITIES. gles formed by the junction of the cylindrical and flat surfaces of the second phalanx near its upper part. It bends the second phalanges on the first; its ac- tion may also be continued so as to clench the hand and to bend it on the arm. 6. The Flexor Profundus Perforans is beneath the flexor sublimis and the flexor ulnaris. It arises fleshy from the oblong concavity of the ulna between the coronoid and olecranon processes, fleshy from the carpal margin of the base of the coronoid process, from the ulnar portion of the interosseous ligament, and from the front of the upper two-thirds of the ulna. The tendons of this muscle are different from those of the other; they commence, like a tendinous mem- brane, in front of it, which is gradually divided into several fasciculi adhering to each other by cellular membrane. The fasciculated character of the ten- dons is still preserved when they go under the ante- rior carpal ligament, and until they begin to disperse as distinct tendons to the four fingers. Each tendon, going in front of its metacarpal bone and of the corresponding phalanges, gets through the slit in the flexor sublimis, and is inserted into the front part of the root of the third phalanx of the fin- ger. It bends the last joint of the fingers, and may flex the hand by increased action like the preceding mus- cle. MUSCLES. 369 7. The Flexor Longus Pollicis lies in front of the radius, but beneath the flexor sublimis. It arises, by an acute fleshy beginning, from the radius just be- low its tubercle; also fleshy from the middle two- thirds of the front of the bone and from the radial portion of the interosseous ligament. The body of the muscle is joined by a small fleshy slip having a tendinous origin from the internal condyle of the hu- merus. A tendon is formed early on the ulnar margin of this muscle, to which the fibres pass obliquely. This tendon goes under the annular ligament of the wrist, through the fossa formed in the short flexor muscle of the thumb, and between the sesamoid bones, to be inserted into the base of the second phalanx of the thumb. It bends the last joint of the thumb. While performing this dissection there are several minutiae which deserve attention. The annular liga- ment of the wrist in front, is a very strong membrane passing across the carpus from the projection of the scaphoides and trapezium on the radial side of the wrist, to the unciform process on the ulnar side. Be- tween it and the concavity of the carpus, an oval foramen is formed for transmitting the tendons of the several flexors. These tendons, though they slide with perfect freedom upon each other, are connected by a dense and elastic cellular membrane, which has 3 A 370 OF THE UPPER EXTREMITIES. the power of keeping them lubricated by a synovial secretion. The Vaginal Ligaments of the fingers extend from the roots of the fingers to the bases of the third phalanges. They are of a ligamento-cartilaginous structure, are attached on each side to the anterior edges of the phalanges, and are much thinner as they pass over the fronts of the finger joints than else- where. They are inelastic, their internal surface is extremely smooth, and kept continually lubricated by synovial fluid. Within the vaginal ligaments small tendinous fraena are found to arise from the first and second phalanges, they run obliquely forwards and terminate in the ten- dons of the two flexor muscles. We may also ob- serve that in front of each joint independently of the swelling of the articular extremities of the bones, the capsular ligament is thickened by an addition of car- tilaginous matter, by which a trochlea is formed. This trochlea facilitates the sliding of the tendons by its smoothness, and the flexions of the phalanges by removing the tendons further from the axis of motion after the same manner with the patella. 8. The Pronator Quadratus is just above the carpal surfaces of the radius and ulna, and between the other muscles and the bone. In the adult it is about two inches wide, and its fibres run across the fore-arm. It arises fleshy and tendinous from the MUSCLES. 371 ridge at the inner surface of the ulna near its lower extremity, and from the front of the bone. It is inserted into the corresponding front surface of the radius. It rotates the radius inwards. of the muscles on the back of the fore-arm. These muscles are ten in number. They arise for the most part from the external condyle and the ridge leading to it, and are extensors either of the fore-arm or of the fingers and thumb. Their origins are less blended with each other than those of the flexor mus- cles, nevertheless between several of them there are intermuscular ligaments which connect them closely. They are superficial and deep seated. 1. The Supinator Radii Longus is situated along the radial edge of the fore-arm immediately beneath the integuments. It arises, fleshy and tendinous, from the higher part of the ridge leading to the external condyle, commencing just below the insertion of the deltoid muscle, and being here placed between the brachialis internus and the short head of the triceps. It forms a thick fleshy belly constituting the external margin of the arm about the elbow joint, and termi- nates about the middle of the radius in a flat tendon. It is inserted, by the tendon, into a small rough ridge on the outer side of the radius just above its styloid process. It rolls the radius outwards. 372 OF THE UPPER EXTREMITIES 2. The Extensor Carpi Radialis Longior is situated beneath the former muscle. It arises, tendi- nous and fleshy, from the space of the external ridge of the os humeri between the supinator longus and the external condyle. It forms a short fleshy belly which terminates in a flat tendon above the middle of the radius. It is inserted, by this tendon, into the posterior part of the root of the metacarpal bone of the fore-finger near the thumb. It extends the hand. 3. The Extensor Carpi Radialis Brevior is beneath the last, but projects somewhat beyond it. It arises, tendinous, from the posterior and lower part of the external condyle and from the external lateral ligament of the elbow joint. It forms a thick fleshy belly placed along the radius which terminates in a flat tendon about the middle of that bone. Its tendon, becoming rounded, is inserted into the posterior part of the base of the metacarpal bone of the second finger. It extends the hand. 4. The Extensor Carpi Ulnaris is superficial, and placed principally parallel with the ulna. It arises, tendinous, from the external condyle, fleshy from the intermuscular ligament and inside of the fas- cia. Crossing very obliquely the upper part of the MUSCLES. 373 radius and the ulna, it also arises fleshy from the back part of the latter bone. Its fibres terminate obliquely in a tendon which goes through the groove of the ulna. It is inserted, by its tendon, into the ulnar side of the base of the metacarpal bone of the little finger. It extends the hand. 5. The Extensor Digitorum Communis is super- ficial, being placed between the extensor ulnaris and the extensor radialis brevior. It arises, tendinous, from the external condyle, and fleshy from the inter- muscular ligament of the contiguous muscles. As it approaches the wrist it sends off four tendons which pass together through a common groove on the back of the radius. On the back of the hand these ten- dons diverge, and near the roots of the fingers send cross slips to each other. Each tendon goes to its respective finger and covers the whole posterior part of it, being spread out into a membrane which adheres to the phalanges from the root of the first to the root of the last. The section of this muscle appropriated to the little finger has a distinct appearance, and sometimes its tendon goes through a distinct fossa in the radius. from which causes it has obtained the name of Auri- cularis. This muscle extends all the joints of the fingers. being the antagonist of the flexors. 374 OF THE UPPER EXTREMITIES. 6. The Sufinator Radii Brevis can only be well seen by detaching the origins of the aforesaid mus- cles; it will then be found in contact with the radius, making a close investment of its head and upper third. It arises, tendinous, from the external condyle of the humerus, tendinous and fleshy from the ridge on the posterior radial edge of the ulna which descends from its coronoid process. Its fibres surround, obliquely, the upper external part of the radius, and are inserted into its tubercle and into the oblique rough ridge corresponding with the upper margin ofuhe pronator teres. At the inter- stice between the radius and ulna, near the anterior edge of this muscle, a fleshy slip is occasionally seen which passes from the radial side of the coronoid pro- cess to the ulnar edge of the radius. This muscle rotates the radius outwards. 7. The Extensor Ossis Metacarpi Pollicis Manus arises, fleshy, from the posterior part of the ulna immediately below the anconeus, from the inter- osseous ligament, and from the back part of the ra- dius just below the insertion of the supinator brevis. It terminates in a rounded tendon which passes over the tendons of the radial extensors and through a groove on the styloid side of the head of the radius. It is inserted, by its tendon, into the base of the metacarpal bone of the thumb and into the external side of the trapezium. MUSCLES. 375 It extends the metacarpal bone of the thumb. 8. The Extensor Minor Pollicis Manus is at the ulnar side of the last muscle. It arises, tendinous, from the back of the ulna below its middle, and fleshy from the interosseous ligament. It adheres to the ra- dius and terminates in a tendon which passes through a groove in the styloid side of the radius along with the last named muscle. It is inserted into the first phalanx of the thumb by its tendon, which is extended to the root of the se- cond phalanx. It extends the first phalanx. 9. The Extensor Major Pollicis Manus arises, by a small tendinous and extensive fleshy origin, from the back of, the ulna above its middle and from the interosseous ligament; it terminates near the wrist in a tendon which passes through a groove on the back of the radius near the ulna. The belly of this mus- cle conceals, very much, the other extensors of the thumb. It is inserted, by its tendon, into the oblong trans- verse tubercle on the back of the base of the second phalanx of the thumb. It extends the second phalanx. The tendons of the two last muscles are much con- nected with each, and are spread in the form of a 376 OF THE UPPER EXTREMITIES. membrane on the back of the thumb, after the man- ner of the extensor tendons of the fingers. 10. The Indicator is a small muscle on the back of the ulna, concealed by the extensor communis and extensor ulnaris. It arises, tendinous and fleshy^ from the back of the ulna commencing near its middle and from the contiguous part of the interosseous ligament. It terminates in a tendon which goes through the same fossa with the extensor communis; it afterwards is joined, about the head of the first phalanx, to the tendon of the common extensor belonging to the fore- finger. With the tendon of the extensor communis it is inserted along the back of the fore-finger to the base of the third phalanx. It extends the fore-finger. At this stage of the dissection it is proper to notice the Posterior Carpal Ligament, which passes from the side of the radius to the side of the ulna. It is two inches in breadth, and seems much like a continuation of the fascia of the fore-arm. It will be found, how- ever strongly attached to the different ridges of the radius and ulna, and from its want of elasticity, per- fectly adapted to prevent the tendons from springing out of their respective grooves. It forms one jugum for the two first extensors of the thumb, another for the radial extensors of the hand, a third for the ten- MUSCLES. 377 don of the third extensor of the thumb, a fourth for the indicator and extensor communis, and a fifth for the extensor ulnaris. OF THE SMALL MUSCLES OF THE HAND. The skin and fat being carefully removed from the palm of the hand, we bring into view the Aponeuro- sis Palmaris. This is a triangular tendinous mem- brane which covers all the hollow of the hand, and is spread over its muscles. It arises from the anterior carpal ligament somewhat narrow; it then spreads out, and dividing into four sections, is fixed to the heads of the metacarpal bones. Each section bifur- cates, to allow the flexor tendons to pass to the fin- gers, and is united to the contiguous sections by trans- verse bands or fraena. The Palmaris Brevis is apt to be cut away un- consciously; it is just below the skin at the inner side of the hand. It consists of separate fasciculi un- equally divided, and arises from the ligament of the wrist, and from the ulnar side of the palmar aponeu- rosis. It is inserted into the skin and fat at the inner mar- gin of the hand, and covers the muscles of the little finger. It contracts the skin of the hand. Sb 378 OF THE UPPER EXTREMITIES. The Aponeurosis being removed, a good view is obtained of the flexor tendons and many of the small muscles of the hand. The Lumbricales are conspicuous; they are four in number, of the size and shape of earth worms. They arise, tendinous and fleshy, from the radial sides of the tendons of the flexor profundus beneath the li- gamentum carpi annulare and a little beyond its ante- rior edge. They terminate in little flat tendons which run along the outer or radial edges of the fingers, and are inserted into the tendinous expansion on the back of the first phalanx of each finger about its middle. They bend the first phalanges. Four muscles constitute the ball of the thumb. 1. The Abductor Pollicis Manus arises, tendi- nous and fleshy, from the anterior surface of the liga- mentum carpi annulare and from the projecting ends of the trapezium and scaphoides. It is inserted, tendinous, into the outer side of the base of the first phalanx of the thumb and into the tendinous membrane derived from the extensors on its back part. It draws the thumb from the fingers. Trfis muscle is next to the skin. MUSCLES. 379 2. The Opponens Pollicis is beneath the abduc- tor, and without its removal can scarcely be seen. It arises, tendinous and fleshy, from the projecting point of the os trapezium and from the adjacent part of the annular ligament. It is inserted, tendinous and fleshy, into the radial edge of the metacarpal bone of the thumb from its base to its head. It draws the metacarpal bone inwards. 3. The Flexor Brevis Pollicis Manus is be- neath the abductor pollicis and at the side of the op- ponens pollicis. A groove is formed in it by the ten- don of the flexor longus pollicis, which divides it into two heads The first head arises,, fleshy, from the points of the trapezoides, trapezium, and from the contiguous part of the internal surface of the annular ligament, and is inserted into the outer sesamoid bone; the sesamoid bone, like a patella, being connected to the first pha- lanx of the thumb by tendon. The second or internal head arises, fleshy, from near the metacarpal surfaces of the magnum and un- ciforme, and from the base of the metacarpal bone of the middle finger. It is inserted into the inner sesa- moid bone, which, like the external, is connected, by ligament, to the first phalanx. The short flexor, as its name implies, bends the first joint of the thumb. 380 OF THE UPPER EXTREMITIES. 4. The Adductor Pollicis Manus lies in the palm of the hand beneath the lumbricales and the tendons of the flexor sublimis and profundus. It arises, fleshy, from the ulnar edge of the metacarpal bone of the second finger between its base and head. It is inserted, tendinous, into the inner part of the base of the first phalanx of the thumb just above the sesamoid bone. It pulls the thumb towards the fingers. The Abductor Indicis Manus is on the radial edge of the hand between the metacarpal bones of the fore-finger and thumb, and is just beneath the skin. It arises, tendinous, from the trapezium, fleshy from the ulnar edge of the metacarpal bone of the thumb between its base and head. Being placed along the side of the metacarpal bone of the fore-finger, it is inserted, by a short tendon, into the radial side of the first phalanx. It draws the fore-finger from the others. There are three muscles constituting the ball of the ulnar side of the hand or of the little finger. 1. The Abductor Minimi Digiti Manus is the most superficial. It arises, fleshy, from the protube- rance on the internal side of the os pisiforme and from the contiguous parts of the annular ligament. It is inserted, tendinous, into the ulnar side of the MUSCLES. 381 first phalanx of the little finger and into the tendinous membrane which covers its back part. It draws the little finger from the rest. 2. The Flexor Parvus Minimi Digiti Manus is beneath the abductor. It arises, fleshy, from the un- ciform process of the os unciforme and from the con- tiguous parts of the annular ligament. It is inserted, tendinous, into the ulnar side of the base of the first phalanx of the little finger, being unit- ed with the tendon of the abductor and with the ten- dinous membrane expanded over the back of the fin- ger. It bends the little finger. The Adductor Metacarpi Minimi Digiti is placed beneath the Abductor and Flexor, next to the metacarpal bone. It arises, fleshy, from the unciform process of the os unciforme and from the contiguous part of the annular ligament of the wrist. It is inserted, tendinous and fleshy, into the fore part of the metacarpal bone of the little finger from its base to its head. It brings the metacarpal bone of the little finger to- wards the wrist, and thereby deepens the hollow of the hand. The Interosseous Muscles fill up the interstices of the metacarpal bones; they are seven in number, four 382 OF THE UPPER EXTREMITIES. On the palm, and three on the back of the hand. The back ones arise by double heads from the contiguous sides of two metacarpal bones; the inner ones have a single head, which comes only from the metacarpal bone of the finger which such interosseous muscle is intended to serve. As a general description they all may be said to arise, fleshy and tendinous, from the base and sides of the metacarpal bones, and to be in- serted tendinous, into the sides of the first phalanges, and into the tendinous membranes on the back of the fingers derived from the tendons of the extensor com- munis. The four first must be looked for on the palm, the three others on the back of the hand. 1. The Prior Indicis is along the radial side of the first metacarpal bone, and arises from the base and side of the same. It is inserted, tendinous, into the radial side of the first phalanx. It draws the fore-finger towards the thumb. 2. The Posterior Indicis is at the ulnar side of the first metacarpal bone. It arises from the base and ulnar side of the same bone, and is Inserted, tendinous, into the ulnar side of the first phalanx of the fore-finger. It draws the fore-finger towards the others. 3. The Prior Annularis is at the radial side of 9 MUSCLES. 383 the metacarpal bone of the third or ring finger. It arises from the base and radial side of the said bone. It is inserted, tendinous, into the radial side of the first phalanx of the ring finger. It draws that finger towards the thumb. 4. The Interosseus Digiti Auricularis is at the radialside of the metacarpal bone of the little finger. It arises from the radial side and base of said bone. It is inserted, tendinous, into the radial side of the first phalanx of the same finger. It draws the little finger towards the others. By removing the tendons of the extensor commu- nis from the back of the hand, we see the three poste- rior or double-headed interosseous muscles. 5. The Prior Medii is between the metacarpal bones of the fore and middle fingers. It arises from the opposite roots and sides of these bones. It is inserted, tendinous, into the radial side of the first phalanx of the middle finger. It draws the mid- dle finger towards the thumb. 6. The Posterior Medii is between the meta- carpal bones of the middle and ring fingers. It arises from the opposite sides and roots of these bones. It is inserted, tendinous, into the ulnar side of the 384 OF THE UPPER EXTREMITIES. first phalanx of the middle finger. It draws the mid- dle finger towards the little. 7. The Posterior Annularis is between the me- tacarpal bones of the ring and little finger. It arises from the opposed sides and roots of these metacarpal bones. It is inserted tendinous into the ulnar side of the first phalanx of the ring finger. It draws the middle towards the little finger. BLOOD-VESSELS. 385 Section IV. OF THE BLOOD-VESSELS OF THE UPPER EXTREMITIES. The Arteries of the Upper Extremity are derived from the Subclavian, the course of which, to the sca- leni muscles, is described in the account of the neck. The subclavian passes over the middle of the first rib between the scalenus anticus and posticus muscles, and afterwards goes between the first rib and the sub- clavius muscle to the arm-pit. Here it is called Ax- illary Artery, (Arteria Axillaris,) and its position is under the tendinous insertion of the pectoralis minor and almost touching it; it then passes, at the internal inferior part of the head of the humerus, parallel with, and bordering on, the internal edge of the coraco bra- chialis muscle. At the posterior fold of the arm-pit it is placed very near the tendon of the latissimus dorsi, between it and the coraco brachialis. Emerg- ing from the axilla at this place, its name is changed into that of Arteria Brachialis. The Arteria Brachialis descends the arm at the internal margin of the lower part of the coraco bra- chialis, and afterwards at the internal margin of the biceps flexor cubiti. At the bend of the arm it is at the inner edge of the tendon of the biceps, and passes 3c 386 OF THE UPPER EXTREMITIES. under its aponeurosis, and a little below the joint it splits into two branches of nearly equal magnitude, thon#adial and the Ulnar Arteries. The relative situation of the great artery with the nerves and veins of the part, should be closely observ- ed; between the scaleni muscles, the greater part of the nerves, forming afterwards the axillary plexus, is above and somewhat posterior to the subclavian ar- tery, but when this artery becomes axillary the nerves unite in various combinations, and surround it like so many cords of a platted whip thong. The axillary vein is below and somewhat in front of the artery, and very near it. These several parts are united by a loose, vascular, adipose, and cellular membrane con- taining many lymphatic glands. 1. The Arteria Dorsalis Superior Scapula varies much in its origin; it comes sometimes from the subclavian, and on other occasions from the up- per part of the axillary. Not unfrequently it is a branch of the inferior thyroid. In either the first or the last case its course is very important to the sur- geon, for it runs along the posterior margin of the clavicle towards its acromial extremity, and in an ope- ration, by being opened, might be mistaken for the subclavian arterj itself. When it cOmes from the ax- illary artery it is tortuous, and has to ascend to its des- tination, being completely out of the way of an ope- ration from above, upon the subclavian artery. Its BLOOD-VESSELS. 38", final distribution is always the same, for it passes through the notch in the upper costa of the scapula, and there divides into branches supplying the supra- spinal muscle and the shoulder joint. 2. The Arteria Mammaria Externa arises from the axillary just above the pectoralis minor. Its dis- tribution into four principal branches, going to cer- tain parts, is uniform, but the origin of these branches varies, for sometimes they come as originally distinct trunks from the axillary artery. They are a. Thoracica Superior, distributed to the parts of the pectoralis major muscle just below the clavicle, some branches going to the pectoralis minor. b. Thoracica Longa, supplying the inferior parts of the great pectoral muscle, the mamma, and integu- ments. c. Thoracica Acromialis, making for the fissure be- tween the deltoid and great pectoral muscle, and distributed to them along the margins of this fissure upwards and downwards. d. Thoracica Axillaris, very irregular in origin and size; when small it is distributed generally to the fat and glands of the axilla; when large it is a trunk, the size of a goose-quill, running on the scapular surface of the serratus major anticus, and distributed to it by branches coming off at right angles. 3. The Scapularis arises from the axillary artery 388 OF THE UPPER EXTREMITIES. about the anterior margin of the teres minor muscle. It passes downwards towards the angle of the scapula in contact with this muscle, and is distributed to the teres major and minor, subscapularis and latissimus dorsi muscles. A little below the neck of the sca- pula a large trunk, the Dorsalis Inferior Scapulae, arises from the scapularis, which winds around the bone to be distributed to the infraspinatus and the contiguous muscles, an anastomosis being formed un- der the neck of acromion process between the dorsa- lis inferior and superior. 4. The Circumflexa Anterior is a small artery about the size of a crow-quill. It arises from the ax- illary just above the superior or posterior margin of the tendon of the teres major and latissimus dorsi. It surrounds half the os humeri just below its head, go- ing between the bone and the coraco brachialis and biceps muscle, being distributed to the articulation and to the contiguous muscles. 5. The Circumflexa Posterior arises from the axillary about the same place with the last, but com- monly a little below; sometimes they have a common trunk. It surrounds the back part of the os humeri, going between the long head of the triceps and the bone by passing between the teres minor and major muscles in the first instance. It is distributed to the BLOOD-VESSELS/ 389 shoulder joint and the contiguous muscles, especially the deltoid. 6. The Profunda Humeri or Spiralis arises from the great artery of the upper extremity just below the tendon of the teres major, where the artery is called Brachial or Humeral. It passes downwards a little distance, and there enters the interstice between the first and the third heads of the triceps muscle. It winds between this muscle and the bone very obliquely downwards, and appears, at last, on the outer side of the arm between the brachialis internus and the supi- nator longus, reaching to the external condyle. In this course the profunda sends many branches to the triceps and to the contiguous muscles. Its origin is sometimes from the scapular or from the posterior circumflex artery. 7. The Profunda Minor is uncertain in its origin, but comes commonly from the humeral two inches below the last; sometimes it is a branch of the last. It is distributed on the internal surface of the triceps extensor, and extends to the internal condyle. 8. The Nutritia is a very small branch from the humeral, arising near the medullary foramen of the os humeri, which it penetrates, and is distributed to the lining membrane. 390 OF THE UPPER EXTREMITIES. J 9. The Anastomotica is a small branch from the humeral, arising about the place where the os humeri begins to expand in order to form the elbow joint. It passes on the internal face of the brachialis inter- nus muscle, and then over the ridge of the internal con- dyle to the groove between the condyle and the ole- cranon process, where it anastomoses with a recurrent branch of the ulnar artery. Several arterioles are also sent from the humeral artery to the biceps, brachialis, triceps, and coraco brachialis, which are too irregular and too small to de- serve description. The Humeral Artery, it has been stated, is divid- ed a little below the elbow joint into two principal trunks, Radial and Ulnar. Sometimes this division is on a line with the joint; at other times it occurs nearer the insertion of the brachialis muscle. The division, however, does occasionally occur in all the space be- tween the axilla and the elbow joint, in which case the radial artery sometimes is just beneath the skin at the elbow, and continues uncommonly superficial to the wrist. The Radialis, in the early part of its course, is at the bottom of the fissure between the pronator teres and the supinator radii longus; afterwards it crosses the insertion of the former, runs parallel with, and in BLOOD-VESSELS. 391 front of the radius to the wrist between the tendons of the supinator longus and of the flexor radialis. At the styloid process it gets between the carpus and the extensors of the thumb, runs a little distance on the radial side of the back of the hand, and then pene- trates to the palm between the bases of the metacar- pal bones of the thumb and of the fore-finger. It fur- nishes the following branches, collateral and termi- nating. 1. The Recurrens Radialis arises about the neck of the radius. It winds around the joint externally between the external condyle and the muscles Coming from it, and anastomoses with the spiralis or pro- funda of the humeral artery, being distributed, in many collateral branches, to the joint and contiguous mus- cles. 2. Several small and irregular muscular branches arise from the radial artery in its progress to the wrist; they have no appropriated names. 3. The Superficialis VoLiE arises from the radial about the inferior margin of the pronator quadratus muscle. It passes superficially over the process of the trapezium to the muscles of the ball of the thumb, and one of its terminating branches joins the arcus sublimis. Sometimes the superficialis volae is the principal branch of the radial. 392 OF THE UPPER EXTREMITIES. 4. The Dorsalis Carpi arises from the radialis at the carpus, runs transversely across the back of the latter, and detaches the posterior interosseous arte- ries of the back of the hand. They anastomose with branches from the ulnar and interosseous arteries of the fore-arm. 5. The Magna Poli^cis, a termininating branch of the radial, comes from it in the palm of the hand just at the root of the metacarpal bone of the thumb. It runs beneath the abductor indicis, and at the head of the metacarpal bone divides into two branches, which run along the sides of the thumb to its extre- mity, where they anastomose and terminate. 6. The Radialis Indicis, arising at the same place with the latter, runs along the metacarpal bone of the fore-finger, and along the radial side of the same fin- ger to its extremity. 7. The Palmaris Profunda is the third terminat- ing branch of the radial artery. It arises near the same place with the two last; crosses the hand be- tween the metacarpal bones and the flexor tendons, thus forming the Arcus Profundus, from which branches proceed to the interossei muscles, and which ends on the ulnar side of the palm of the hand by a branch to the Arcus Superficialis, BLOOD-VESSELS. 393 The Ulnar Artery, (Arteria Ulnaris,) one of the forks of the brachial at the elbow, passes more in a line with it than the radial artery does. It goes, im- mediately after its origin, under several of the muscles of the internal condyle and between the flexor subli- mis and profundus, being deeply seated; getting from beneath the flexor sublimis it afterwards runs paral- lel with the ulna or nearly so, lying on the flexor pro- fundus between the flexor ulnaris and the ulnar mar- gin of the flexor sublimis, and concealed two-thirds of the way down the fore-arm by the overlapping of these muscles. At the thin part of the fore-arm, commonly called the wrist, it is superficial, and may be felt pulsating in the living body at the radial mar- gin of the tendon of the flexor ulnaris. The ulnar artery, at the carpus, takes a very dif- ferent course from the radial, for it passes over the anterior annular ligament of the carpus just at the radial side of the os pisiforme, to which it is held by a small ligamentous noose, and then proceeds to the palm of the hand. Between the aponeurosis palma- ris and the flexor tendons it forms that curve from the ulnar to the radial side of the hand called the Arcus Sublimis. This curve commonly begins a little be- yond the anterior margin of the annular ligament, and presenting its convexity forwards, terminates about the middle of the ball of the thumb at its inner margin. 3d 394 OF THE UPPER EXTREMITIES. The branches sent from the ulnar artery are as fol- low: 1. The Recurrens Ulnaris arises from the ulnar about the lower part of the tubercle of the radius, and winding upwards is distributed in small branches to the muscles of the internal condyle. One of its ra- muscules goes between the internal condyle and the olecranon process to anastomose with the arteria anastomotica of the humeral. 2. The Interossea arises from the ulna just be- low the other. It is a large trunk, and proceeds but a little distance when it divides into two principal branches called anterior and posterior interosseal ar- teries. a. The Interossea Anterior is much the larger; it runs in contact with the interosseous ligament to the upper margin of the pronator quadratus, giving off branches to the deep-seated muscles of the fore-arm in its course. Under the pronator it perforates the in- terosseous ligament and distributes branches to the back of the carpus and of the hand, which anastomose with branches of the radial and posterior interosseal. b. The Interossea Posterior is sometimes a sepa- rate trunk, arising from the ulnar just above the for- mer. In either case it soon perforates the interosseous ligament to get to the back of the fore-arm. Here it sends backwards a Recurrent Branch to the back of BLOOD-VESSELS. S95 the elbow, which anastomoses with the recurrens ul- naris and radialis. It then proceeds downwards, being deeply seated and distributed to the different muscles on the back of the fore-arm. Some of its branches, as was mentioned, reach the wrist, and anastomose with the carpal arteries. 3. The ulnar artery, in its descent on the fore-arm; sends off many small and irregular muscular branches called by Professor Chaussier, Cubito-musculaires: they do not require description. 4. The Dorsalis Manus leaves the ulnar at the lower end of the fore-arm, and passes under the ten- don of the flexor ulnaris to the back of the hand. It there meets ramuscules of the radial and interosseous, and conjointly they supply with very small branches the back of the wrist, of the metacarpus and of the fingers. 5. As the Arcus Superficialis is about beginning, the ulnar artery sends superficial but small branches to the integuments of the palm. And a little further on, a considerable branch, which dives into the bot- tom of the palm, through the muscles of the little finger, and joins the ulnar extremity of the arcus profundus; this is the Cubitalis manus profunda of Haller. 396 OF THE UPPER EXTREMITIES 6. The Arcus Sublimis then sends a branch to the ulnar side of the little finger. Afterwards in suc- cession three digital branches are sent off, which, ar- riving at the interstices between the heads of the me- tacarpal bones, each divides into two branches to supply the sides of the fingers which are opposite to each other; one branch is called Digito radial, the other Digito ulnar, according to the side of the fin- ger on which the artery may be placed. The Digital Arteries, before they divide, receive each a small branch from the arcus profundus. The digito radial, and ulnar arteries pass along the front sides of the fingers to their extremities; at the joints and extremities anastomoses between the arteries of the two sides of the same finger frequently occur. The Arcus Superficialis terminates on the radial side of the palm by a branch which joins the artery of the thumb coming from the radial. The most frequent arrangement of the arteries of the hand is what has been just described; anatomists are, however, not all agreed on this point. It would probably be more just to say, judging from our col- lection in the University, that this occurs more often than any other single arrangement. The variety, in fact, is so great that before a hand is opened it is not possible to say in what manner its arteries will be dis- BLOOD-VESSELS. 397 tnbuted. Sometimes the radial artery furnishes one- half of the arcus sublimis, and the ulnar the other. On other occasions the interosseous artery is conti- nued as a large trunk over the ligament of the wrist and across the root of the thumb to join the arcus sublimis. veins of the upper extremitv • These Veins are abundantly supplied with valves, and are superficial and deep-seated; the former lying beneath the skin have original names; the latter at- tending the arteries, on all occasions, are called after them. Anastomoses are numerous in both sets, but are particularly so in the superficial, where plexuses are formed which surround the arm. Three principal superficial trunks are formed on the lower part of the fore-arm, one on its radial side, another on its ulnar, and the third between the two. 1. The Cephalica first arises about the root of the thumb and fore-finger on the back of the hand; a dis- tinct trunk is formed which winds obliquely over the radius, and then runs along the external edge of the fore-arm to the elbow joint. The cephalic ascends afterwards along the external edge of the biceps flexor muscle, lies over the interstice between the pectoralis major and deltoid muscles, and ascends to within 398 OF THE UPPER EXTREMITIES. eight or ten lines of the clavicle, when it dips into the axilla to join the axillary vein. In the whole of this course it may be seen easily beneath the skin. 2. The Vena Basilica arises, by several branches, from the back of the hand, principally on the ulnar side, one of which, placed between the metacarpal bone of the little finger and the ring finger, is called Salvitella. From this origin the basilic vein* gets to the ulnar side of the fore-arm and continues so to the elbow joint, receiving, on either side, anterior and pos- terior ulnar branches. At the elbow it is on the in- ner edge of the biceps muscle, and the pulsation of the brachial artery may be felt beneath it. It ascends regularly at the inner edge of the biceps, and about the middle of the arm becomes, by a junction with other veins, the Brachial Vein. 3. The Vena Mediana arises, by branches, from the wrist and from the palm of the hand; it forms a trunk in the front of the fore-arm which, three or four inches below the bend of the arm, bifurcates. One branch, the Mediana Cephalica, joins the cephalic vein; the second, called the Mediana Basilica, joins the basilic vein. The deep-seated Veins, called Venae Satellites or Comites, are found in company with every artery of the upper extremity, there being, for the most part, BLOOD-VESSELS. 399 one vein to each side of the artery. They anastomose frequently by branches which cross the artery. At the elbow, the radial, ulnar, and interosseous satellites unite and form a plexus over the bifurcation of the brachial artery; from which plexus a short large branch goes outwards to join one of the superficial veins. The trunk, formed by the union of the satellites of the fore-arm, passes upwards on the inner side of the brachial artery and receives the small veins from the different muscles. Sometimes it joins the basilic about the middle of the humerus; on other occasions it joins it near or in the axilla, from which union re- sults the axillary vein. The Vena Axillaris receives the veins corre- sponding with the circumflex, scapular, and thoracic arteries, in their proper succession. It is fixed be- neath the artery and very near it in the same sheath of cellular substance. Under the clavicle it becomes Vena Subclavia; and as such it passes between the cla- vicle and the first rib at the inner side of the subcla- vian artery. It then leaves the artery to go in front of the scalenus anticus, whereas the artery goes be- tween this muscle and the medius. After crossing the first rib it receives the superior dorsal vein of the sca- pula, the external jugular, and afterwards the internal jugular, besides several small veins from the skin and muscles of the neck. 400 OF THE UPPER EXTREMITIES. Section V. OF the nerves of the upper extremities. The four inferior cervical and the first dorsal nerves supply the upper extremity by an appropria- tion of nearly the whole of their anterior branches, which are of considerable magnitude, especially the three intermediate ones. They come out between the anterior and middle scalenus muscles, being situ- ated above and posterior to the subclavian artery, at various heights according to the origin of the nerve individually. Almost immediately after disengaging themselves from the scaleni muscles, they commence the formation of a plexus which surrounds the artery and continues with it to the lower part of the axilla. The fourth and fifth cervical nerves unite into a com- mon trunk which splits into two; the seventh cervical and the first dorsal do the same; the sixth cervical also bifurcates. It is under various combinations of these different primary divisions that the axillary plexus is formed, from which proceeds the different nerves of the upper extremity. This plexus, from its close connection witji the great artery, must, of course, go between the scalenus muscle and the first rib, and, in the upper part of the axilla, separate the vein from NERVES. 40, the artery in some measure. The following branches are given off by the brachial plexus, besides the fila- ments to the sympathetic and phrenic in front, from its roots already mentioned in the account of the Neck. i 1. The Nervus Scapularis is a small branch com- ing from the upper part of the plexus, commonly the fourth cervical nerve. It accompanies the arteria dor- salis scapulae superior to the foramen in the upper costa of the scapula, and is distributed to the muscles on the back of the scapula. 2. The Nervi Thoracici are primarily two or three in number. They arise from the middle of the plexus, and are divided into anterior and posterior branches, the former being distributed upon the pec- toralis major and minor, the latter upon the serratus major anticus. 3. The Nervi Subscapulares of Bichat are about three in number; they come also from the central parts of the plexus to be distributed upon the teres major, latissimus dorsi, and subscapularis. 4. The Nervus Axillaris, or Circumflexus, comes from the lower part of the brachial plexus. It follows the course of the posterior circumflex artery, winding around the upper part of the os humeri be- 3 e 402 OF THE UPPER EXTREMITIES. tween the teres minor and major in order to get to the internal surface of the deltoid muscle, where it ter- minates. In its passage it also furnishes branches to the subscapularis, the teres major and minor, the in- fraspinatus, and to the integuments on the back of the shoulder and arm. 5. The Nervus Cutaneus Internus proceeds from the lower part of the brachial plexus, and follows the course of the basilic vein to the elbow or near it. In its descent it detaches small cutaneous filaments anteriorly to the integuments of the biceps, and poste- riorly to those of the triceps. A little above the bend of the elbow, commonly where the median basilic joins the basilic vein, it divides into two terminating branches of nearly equal magnitude. The one next the internal condyle lies in front of the basilic vein just at its junction with the median basilic, and conti- nues in front and parallel with it for some inches. It is distributed, by many ramifications, to the skin of the ulnar side of the fore-arm and back of the hand, some of the branches winding around to the back part of the fore-arm. The other branch of the inter- nal cutaneous passes beneath the median basilic vein about six lines from its junction with the basilic, and is distributed to the integuments on the middle front of the fore-arm. Before this latter branch reaches the median basilic vein it sends off a cutaneous filament NERVES. 403 which crosses the median basilic in front, about half- way in the course of this vein. 6. The Nervus Musculo Cutaneus comes from the middle of the brachial plexus. It perforates ob- liquely the upper part of the coraco-brachialis muscle, to which it dispenses filaments, it then passes between the biceps and brachialis internus muscles, giving also filaments to both of them. Its course being remark- ably oblique under the biceps muscle, it makes its appearance superficially, only a little above the elbow joint near the external condyle. It then passes su- perficially between the skin and the supinator radii longus muscle, distributing filaments in its course, and near the lower part of the radius divides into two orders of fibres, one of which is distributed on the palmar side of the hand, and the other on the dorsal to the integuments. 7. The Nervus Radialis, or Musculo Spiralis, arises from the upper portion of the brachial plexus. It is a large trunk which winds spirally around the os humeri between the triceps muscle and the bone, entering the fissure between the third and the first head of the triceps. It appears on the outside of the os humeri between the brachialis internus and the triceps muscles, running for some inches in con- tact with their intermuscular ligament. While beneath the triceps it sends several branches to its heads 404 OF THE UPPER EXTREMITIES. There are three principal trunks afterwards to thi& nerve. a. The Ramus Superficialis Dorsalis is sent from it on a line with the point of the deltoid muscle. This branch, then, goes just below the skin parallel with and over the external ridge of the os humeri, it of course crosses the origin of the muscles of the ex- ternal condyle. It continues superficial on the pos- terior external edge of the supinator radii longus mus- cle, and terminates in the integuments on the back of the hand. The continued trunk of the muscular spiral goes in the interstice between the extensor muscles and the brachialis internus, and at the external condyle divides into the other two branches, from which fila- ments proceed to the contiguous heads of the mus- cles. b. The Ramus Dorsalis Profundus perforates the supinator brevis muscle, getting beneath the radial extensors to the back of the fore-arm, it is then dis- tributed in numerous filaments to the muscles on the back of the fore-arm, some of its branches reaching to the wrist. c. The Ramus Superficialis Anterior seems to be a continuation of the main trunk of the nerve, and descending at the anterior margin of the supinator radii longus muscle, it joins with the radial artery and continues in its company to a short distance below the middle of the radius. Here it crosses the bone NERVES. 405 obliquely beneath the tendon of the supinator lon- gus, and then divides into a palmar and a dorsal ra- muscule; the first being distributed to the muscles and integuments of the thumb, the second terminating so as to supply the-back of the hand, of the thumb, fore, middle, and ring fingers to their extremities. 8. The Nervus Medianus, like the other nerves, arises from the brachial plexus. It descends the arm at the inner edge of the biceps muscle along the anterior surface of the humeral artery, adhering firmly to it and the deep-seated veins by cellular sub- stance. As far as the elbow it sends off no branch of importance. There, it lies at the side of the biceps tendon, crossing the lower part of the brachialis in- ternus, and being beneath the aponeurosis of the biceps. It then perforates the pronator teres and gets between the flexor sublimis digitorum, and the flexor longus pollicis, and enters the palm of the hand under the ligamentum carpi at the radial edge of the tendons of the flexor sublimis. In the palm it is situated beneath the aponeurosis and the arcus sub- limis. The median nerve dispenses the following branches: At the bend of the arm it furnishes filaments to the heads of the first layer of muscles, of the fore-arm, and a little below, it detaches the nervus interosseus which supplies filaments to the flexor longus pollicis and flexor profundus. The interosseous nerve then 406 OF THE UPPER EXTREMITIES. descends with the interosseous artery in front of the interosseous ligament, and terminates in the pro- nator quadratus. Before the median nerve reaches the wrist it sends a branch which supplies with filaments the muscles and integuments of the ball of the thumb. In the palm of the hand it divides and subdivides so as to furnish the two sides of the thumb, of the fore, of the middle, and one side of the ring finger with branches, which reach their ex- tremities along with the digital arteries. 9. The Nervus Ulnaris comes from the lowest section of the brachial plexus. It descends along the internal anterior part of the triceps muscle in a groove formed between it and the intermuscular ligament. diverging in this course gradually from the median nerve till it reaches the elbow, when it is at its greatest point of separation. At the elbow it is behind the internal condyle, in the groove between it and the olecranon, and separates the two heads of the flexor ulnaris muscle. It then gets to the fore-arm between this muscle and the flexor profundus digitorum, and continues between them to within two inches of the wrist joint, when it detaches the Ramus Dorsalis. The Ramus Dorsalis slips between the ulna and the tendon of the flexor ulnaris, runs along the inter- nal margin of the ulna to the carpus, when it divides into ramuscules which supply the ulnar side of the integuments on the back of the hand and the backs NERVES. 407 of the two last fingers. At the interval between the heads of the metacarpal bones of the middle and ring fingers, a considerable ramuscule joins one from the anterior branch of the radial nerve. The Ulnar Nerve, having given off this dorsal branch, descends along the radial margin of the ten- don of the flexor ulnaris and of the os pisiforme above the annular ligament to the palm of the hand. Get- ting beneath the aponeurosis, it there detaches first a deep-seated branch, which penetrates the muscles of the little finger to supply them, the interossei, and the short flexor of the thumb. The ulnar nerve then furnishes a superficial branch, and afterwards divides into three; one for the ulnar side of the little finger, another for the opposing sides of the little and ring finger, and a third which joins the most internal digi- tal branch of the median nerve. To conclude; the dissector should also attend to what are called the Intercosto-Humeral Nerves. They consist of a branch from the second, and an- other from the third intercostal, which pass out at the fore and lateral parts of the thorax, the first from beneath the second rib, and the other from beneath the third rib. The first intercosto-humeral, being connected with a filament from the internal cutaneous, is distributed upon the axillary glands, and the integuments of the axilla and inner side of the arm. The second, being 408 OF THE UPPER EXTREMITIES. joined by filaments from the first, is chiefly distributed to the integuments on the back of the arm, some of its branches reaching the elbow. The numbness of the inner side of the arm in angina pectoris, is sup- posed to be owing to the sympathy of these nerves with the cardiac. PART III. CHAPTER II. Of the Lower Extremities. Section I. of the muscles. There are several muscles, common to the lower extremities and to the trunk, under either of which heads they may be properly placed. It suits my ar* rangement better to consider them under the first, as they are most frequently studied in that way, by the young dissector. The lower Extremity, from the pelvis to the foot, is enveloped by a strong Fascia or Tendinous Mem- brane, lying between the skin and the muscles. This fascia consists, for the most part, of ligamentous fibres, passing in the direction of the length of the limb, se- cured together by transverse filaments, of the same matter, but by no means so abundant. Its structure undergoes some variations; its greater part is decid- edly of the character just mentioned; but at the groin 3f 410 OF THE LOWER EXTREMITIES. it is between ligament and cellular membrane; the latter occasionally predominates so much, that the appearance of the first is lost, particularly in corpu- lent subjects. On the contrary, in the lean and such as have suffered from pressure and irritation of the part by hernial protrusion, the ligamentous structure is well expressed. On the Gluteus Maximus also this fascia exists as a condensed Cellular membrane, sending in its processes between the fasciculi of the muscle. The thickness of the Fascia Femoris is not uni- form. On the outer side of the thigh, knee, and hip, it is very thick and strong; on the inner side it is thin, and, compared with the other, weak. It is thick on the anterior part of the leg, and somewhat thinner on the posterior, but in neither is it so thick as at the outer part of the thigh. At the ancle it is connected with the bony prominences around it, and increasing in thickness, it constitutes the annular ligament of the joint for confining the tendons on its anterior part. It is also extended over the foot, and is connected at different points to its periphery so as to keep itself tense. This membrane is very closely attached to the cellular membrane at every point of its external sur- face; and is kept tense all over by its bony connec- tions. Above it arises from the exterior margin of the pelvis, as constituted by the pubis, Poupart's liga- ment, the crista of the ilium, the side of the sacrum MUSCLES. 411 and the ischium. At the knee it is fastened to the condyles of the os femoris, and to the heads of the tibia and fibula. On the posterior part of the thigh it sends in a long process, by which it adheres to the li- nea aspera. Its connection with the knee and ancle below, fixes it on the leg, besides which it adheres to the spine of the tibia. Its connection with the muscles of the lower extre- mity is very interesting; to some of them it adheres by its internal face, and to others it does not. To the muscles of the hip it adheres closely, and gives origin to some of the fibres of the gluteus medius. To the muscles of the exterior face of the thigh its adherence is generally loose, and indeed in some parts scarcely deserves to be considered as such, as where the inter- nal surface of the fascia is opposed to the tendinous facing of the vastus externus muscle. On the internal semicircumference of the thigh, it adheres somewhat closely to the muscles by cellular membrane. On the leg it is in close connection with the muscles of its an- terior and fibular side, many of their fibres arising from it, but on the posterior face of the leg it is rather loosely fixed to them. From the internal face of the fascia, prolongations of cellular membrane of various densities, sometimes ligamentous, are sent in between most of the muscles. These prolongations separate the muscles from each other, form sheaths in which they repose, and preserve them in their position in some instances. As an envelop to the muscles of the 412 OF THE LOWER EXTREMITIES leg the fascia is highly useful in supporting and sus- taining their action. The knowledge of its peculiar connection at different parts of the lower extremity, is all important in the management of abscesses of that region. Though useful, it is not indispensable to make a complete dissection of the fascia at once, but the cir- cumstances mentioned should be very carefully ob- served in extending downwards the muscular dissec- tion. The dissection of the fascia would not inter- fere with the preservation of the limb for the mus- cles. The Psoas Magnus muscle arises, fleshy, from the sides of the bodies of the last dorsal and of the four upper lumbar vertebrae, and from the transverse pro- cesses of all the lumbar vertebrae. It forms an ob- long fleshy cushion on the side of the lumbar verte- brae, and, constituting the lateral boundary of the in- let to the pelvis, it passes out of the pelvis under Pou- part's ligament about its middle. It is inserted, tendinous, into the trochanter minor of the os femoris, and fleshy for an inch below it. It bends the body forwards, or draws the thigh up- wards. The Iliacus Internus occupies the concavity of the ilium, being on the outside of the psoas magnus, It arises, fleshy, from the transverse process of the MUSCLES. 41g last lumbar vertebra, from the inner margin of the crista of the ilium, from its whole concavity, from the anterior edge of the concavity of the ilium at and above the anterior inferior spinous process, and from that part of the capsule of the hip joint nearthis process. This muscle terminates in the tendon of the psoas magnus just above the insertion into the trochanter minor. It has the same action with the psoas magnus. The Psoas Parvus arises, fleshy, from the conti- guous edges of the last dorsal and first lumbar verte- brae at their sides, and from the intervertebral liga- ment. It is at the anterior and internal edge of the psoas magnus; has a short belly and a long tendon by which it is inserted into the linea innominata, about half-way between the spine of the pubis and the junc- tion of this bone with the ilium. The tendon, be- sides, is expanded into the fascia iliaca. Its use seems to be to draw upwards the sheath of the femoral vessels which is derived from the fascia iliaca, and consequently to draw upwards the vessels themselves, which probably diminishes the tendency to injury from their too great or sudden flexion. This muscle is sometimes wanting. I have thought best to place it in this part of the description, from its connection with the psoas mag- nus and femoral vessels, though it does not come es- 414 OF THE LOWER EXTREMITIES. sentially under the structure belonging to the lower extremity. The Sartorius arises, by a short tendon, from the anterior superior spinous process of the ilium; a mus- cle of various breadths in different subjects is then formed, whose fibres are in the direction of its length. It passes in a spiral course to the inner side of the thigh and the internal condyle, and, winding under the head of the tibia, advances forwards so as to be inserted into the side of the lower part of its tubercle by a broad tendon. The lower part of the tendon is continued into the fascia of the leg, by which this muscle is preserved in its spiral direction. It is superficial, lying its whole course immediately beneath the fascia femoris; it crosses the rectus femoris, vastus internus, and triceps adductor; at the lower part of the thigh, just above the knee, it is between the tendon of the latter and that of the gracilis. It bends the leg and draws it obliquely inwards. The Tensor Vaginae Femoris is a short muscle just on the outer side of the origin of the sartorius; it arises, tendinous, from the anterior superior spinous process of the ilium, and passes downwards and some- what backwards between two laminae of the fascia fe- moris. It is inserted, a little below the level of the trochan- MUSCLES. 415 ter major, into the inner face of the fascia femoris. It rotates the foot inwards, and makes the fascia tense. The Rectus Femoris is in front of the thigh bone and just beneath the fascia femoris. It is a complete penniform muscle, fleshy in front for the most part, but faced behind with tendon. It arises, by a round tendon, from the anterior inferior spinous process, which is joined by another tendon coming from the superior margin of the acetabulum. It is inserted into the superior surface of the pa- tella by a strong tendon, and intermediately by the ligamentum patellae into the tubercle of the tibia. It extends the leg. Under the rectus femoris the anterior and lateral parts of the thigh bone are enveloped by a large mus- cular mass, considered, by most anatomists, as three distinct muscles, called Vastus Externus, Vastus In- ternus, and Cruraeus or Cruralis. Their heads are very distinguishable from each other, but below they are inseparably united and join with the patella. The Vastus Externus, a very large muscle on the outside of the thigh, arises, tendinous and fleshy, from the upper part of the os femoris immediately be- low the trochanter major. Its origin commences in front, and passes obliquely around the bone to the linea aspera. It continues afterwards to arise the 416 OF THE LOWER EXTREMITIES. whole length of the linea aspera, and from the upper half of the line running from it to the external con- dyle. Its fibres pass inwards and downwards, and are in- serted, by a flat tendon, into the external edge of the tendon of the rectus, and also into the external upper part of the patella. This muscle has a broad tendi- nous surface exteriorly and above; at its lower part it has a tendinous facing on the side next to the bone. It also extends the leg. The Vastus Internus covers the whole inside of the os femoris. It arises, by a fleshy and pointed ori- gin, in front of the os femoris just on a level with the trochanter minor, tendinous and fleshy from the whole length of the internal edge of the linea aspera, and from the line leading from it to the internal condyle. It fibres descend obliquely, and are inserted by a flat tendon into the internal edge of the tendon of the rectus, and into the upper internal edge of the patella. It also extends the leg. The Cruraeus Muscle is almost completely over- lapped and concealed by the two vasti, and is imme- diately behind the rectus femoris. The edge of the vastus externus above is very distinguishable from it, as it overlaps it, and is rounded off, besides being somewhat separated by vessels. But the origin of the vastus internus is not so distinguishable, as the MUSCLES. 417 fibres of the two muscles run into each other, it is therefore necessary most frequently to cut through some of the fibres on the internal face of the os fe- moris on a level with the trochanter minor. The cruraeus will then be seen to arise, fleshy, from all the fore part of the bone, and from all its outside as far as the linea aspera Between the internal edge of this muscle and the linea aspera, the interior face of the os femoris is naked the breadth of an inch along the whole shaft of the bone, which is very readily seen by turning off the vastus internus. The Cruraeus is inserted into the posterior face of the tendon of the rectus below, and into the upper surface of the patella. It also extends the leg. The Ligamentum Patellae is the common cord by which the action of the four last named muscles is communicated to the tibia. It is a flattened thick tendon an inch and a half wide, arising from the in- ferior edge of the patella, and inserted into the tuber- cle of the tibia. Besides this a fascia or tendinous expansion comes from the inferior ends of these mus- cles, which extends itself over the whole of the an- terior and lateral parts of the knee joint, and is in- serted into the head of the tibia and of the fibula. Through this it happens that even when the patella or its tendon is fractured, some motion or extension may be communicated to the leg from the thigh.* * A case of this kind is now in the Philadelphia Alms-house, 3 G 418 OF THE LOWER EXTREMITIES. The Gracilis is a beautiful muscle at the inner margin of the thigh, which lies immediately under the fascia, and extends from the pelvis to the leg. It arises, by a broad thin tendon, from the front of the os pubis just at the lower part of its symphysis, and from its descending ramus; the muscle tapers to a point below, and a little above the knee terminates in a round tendon which passes behind the internal condyle of the os femoris and the head of the tibia. It then makes a curve forwards and downwards at the internal side of the latter, and is inserted at the late- ral and inferior part of its tubercle. The tendon at the knee is beneath the tendon of the sartorius. This muscle is a flexor of the leg. The Pectinalis is a short fleshy muscle at the inner edge of the psoas magnus. It arises, fleshy, from the concavity on the upper face of the pubis between the linea innominata and the ridge above the obturator foramen, and is inserted, tendinous, into the linea aspera immediately below the trochanter minor. It draws the thigh inwards and forwards. The Triceps Adductor Femoris is a large mus- cular mass consisting of three distinct portions, which are placed at the inner side of the thigh, and contri- bute much to fill up the vacuity between the thigh bones above. MUSCLES. 419 1. The Adductor Longus comes, by a rounded short tendon, from the upper front part of the pubis near its symphysis; it forms a triang-dar belly which increases in breadth in its descent, and is inserted into the middle third of the linea aspera at its inner edge. This muscle, as the subject lies on its back, is up- permost; its origin is between that of the pectinalis and of the gracilis, its upper edge is in contact with the lower edge of the pectinalis. 2. The Adductor Brevis is the smallest of the three; it is situated beneath the adductor longus and pectinalis, and on the outside of the gracilis. It arises by a rounded tendon from the middle front part of the pubis between its symphysis and the foramen thyroideum, just below the origin of the first adduc- tor. It is inserted into the upper third of the inner edge of the linea aspera, between the trochanter minor and the upper edge of the adductor longus, by a flat thin tendon. 3. The Adductor Magnus is below the other two, and is by far the largest. It arises, fleshy, from the lower part of the body of the pubis and from its descending ramus, also from the ascending ramus of the ischium as far as its tuberosity, occupying the 4,20 OF THE LOWER EXTREMITIES. whole bony surface between the foramen thyroideum below, and the margin of the pelvis. It is inserted, fleshy, the whole length of the linea aspera, and on its internal margin a tendon is gradu- ally generated which passes downwards to be insert- ed into the upper part of the internal condyle of the os femoris, and by a thin edge or expansion into the line leading from the linea aspera to the internal con- dyle. The adductor magnus separates the muscles on the anterior from such as are on the posterior part of the thigh, and its insertion is closely connected with the origin of the vastus internus, the two surfaces adher- ing by a short and compact cellular membrane. The three adductors contribute to the same end, that of drawing the thigh inwards. The subject should now be turned over in order to enable us to study the muscles on the back of the limb. The Gluteus Magnus arises, fleshy, from the pos- terior third of the spine of the ilium, from the side of the sacrum below it, from the side of the os coccygis, and from the posterior surface of the large sacro- sciatic ligament. The fibres of this muscle are col- lected into large fasciculi with deep interstices be- tween them, and the lower edge of it is folded over the sciatic ligament. MUSCLES. 421 Its fibres pass obliquely forwards and downwards, and terminate in a thick broad tendon, the upper part of which goes on the outside of the trochanter major, and is very strongly inserted into the fascia femoris, and the lower part is inserted into the upper third of the linea aspera, going down as far as the origin of the short head of the biceps flexor cruris. This muscle is placed immediately under the skin, the fasciculi being separated to some depth by pro- cesses from the fascia femoris. It covers nearly all the other muscles on the back part of the pelvis, laps over its inferior margin laterally, and conceals the origins of the hamstring muscles. It draws the thigh backwards. The Gluteus Medius arises from the whole length of the spine of the ilium, except its posterior part, and from that part of the dorsum of the bone which is between its spine and a semicircular ridge extend- ing from the anterior superior spinous process to the sciatic notch; also from the lunated edge of the os ilium between the anterior superior and anterior in- ferior spinous processes, and from that part of the in ner face of the fascia femoris which covers it. The anterior superior part of this muscle is not co- vered by the gluteus magnus, but lies before it. Its fibres converge, and are inserted, by a broad thick tendon, into the upper surface of the trochanter ma- 422 OF THE LOWER EXTREMITIES. jor, and into the upper anterior part of the shaft of the bone just in front of the trochanter. It draws the thigh backwards and outwards. The Gluteus Minimus arises from that part of the dorsum of the ilium between the semicircular ridge just spoken of and the margin of the capsular ligament of the hip joint. It is entirely concealed by the gluteus medius. Its fibres converge and terminate in a round ten- don, which is inserted into the anterior and superior part of the trochanter major, just within the anterior insertion of the gluteus medius. It abducts the thigh, and can also rotate the limb inwards. There are several small muscles about the hip joint, the most of which can be seen by the removal of the gluteus magnus. The Pyriformis arises, fleshy and tendinous, with- in the pelvis, from the anterior face of the second, third, and fourth bones of the sacrum. It forms a conical belly which passes out of the pelvis at the up- per part of the sacro-sciatic foramen, receiving a slip of fibres from the posterior inferior spinous process of the ilium. It is inserted, by a round tendon, into the upper MUSCLES 423 middle part of the trochanter major within the inser- tion of the gluteus medius. It rotates the limb outwards. The Gemini are two small muscles closely con- nected with each other, which are situated lower down on the limb than the pyriformis. The upper one arises from the posterior part of the root of the spinous process of the ischium; the lower from the upper back part of the tuberosity of the ischium. Being parallel to each other, and connected by their contiguous edges, they are inserted together into the posterior part of the thigh bone at the root of the trochanter major, where the deep cavity is. They also rotate the limb outwards. The Obturator Internus muscle is principally situated within the cavity of the pelvis. It arises, fleshy, from all the pelvic margin of the foramen thy- roideum, except where the obturator vessels go out, and from the internal face of the ligamentous mem- brane stretched across it; also from the upper part of the plane of the ischium and just below the linea in- nominata; its fibres converge, and, forming a tendon, pass out of the pelvis over the trochlea of the ischium between the sacro-sciatic ligaments. The tendon is placed between the gemini muscles, which form a sheath for it: and it is inserted into the 424 OF THE LOWER EXTREMITIES. pit on the back of the os femoris at the root of the trochanter major. It rotates the limb outwards. The Qijadratus Femoris is below the other mus- cles. It arises, tendinous and fleshy, from the ridge on the outer side of the ischium which constitutes the exterior boundary of the tuberosity. Its fibres are transverse, and are inserted, fleshy, into the rough ridge of the os femoris on its back part which goes from one trochanter to the other. It rotates the limb outwards. The Obturator Externus is concealed, in front, by the pectineus and triceps adductor, and behind by the quadratus femoris; to get a satisfactory view of it, therefore, these muscles should be detached from the bone. It arises from the whole exterior circumfer- ence of the foramen thyroideum, excepting the place where the obturator vessels come out, and from the exterior face of the ligamentous membrane stretched across it. The fibres of this muscle converge, pass beneath the capsular ligament of the hip joint adhering to it, and terminate successively in a round tendon which is inserted into the inferior part of the cavity on the posterior surface of the os femoris, at the root of the trochanter major. The course of the tendon of this MUSCLES. 425 muscle is marked on the neck of the thigh bone by a superficial fossa. It rotates the thigh outwards. The Biceps Flexor Cruris constitutes the outer hamstring, and is situated on the posterior outer part of the thigh; it arises by two heads. The first, called the long head, has an origin, in common with the se- mitendinosus, from the upper back part of the tube- rosity of the ischium by a short tendinous head which, in its descent, is changed into a thick fleshy belly. The other, called the short head, arises, by an acute fleshy beginning, from the linea aspera just below the insertion of the gluteus magnus, and is continued along the lower part of the linea aspera from the ridge leading to the external condyle. A thick tendon is gradually formed on the outside of the muscle which is inserted into the upper part of the head of the fibula. This muscle flexes the leg on the thigh. The Semitendinosus is on the inside of the thigh between the biceps and gracilis; it is superficial, be- ing immediately under the fascia, and arises, in cdm- mon with the biceps, from the back part of the tu- berosity of the ischium; it also adheres, for three or four inches, to the inner edge of the tendon of the long head of the biceps. About four inches above the knee it terminates in 3h 426 OF THE LOWER EXTREMITIES. a longjround tendon which passes behind the internal condyle and the head of the tibia, and is reflected for- wards to be inserted into the side of the tibia just be- low its tubercle and very near it, being lower down than the insertion of the tendon of the gracilis. It flexes the leg on the thigh. The Semimembranosus is at the inner side of the thigh, its upper part is concealed by the semitendi- nosus and the origin of the long head of the biceps, and below it projects between these two muscles. It is in contact with the posterior surface of the triceps magnus. It arises, by a thick round tendon, from the exterior upper part of the tuberosity of the ischium, which tendon soon becomes flattened and sends off the mus- cular fibres obliquely from its exterior edge, to a cor- responding tendon below. The latter passes behind the internal condyle and the head of the tibia, dis- patches a thin aponeurotic membrane under the inner head of the gastrocnemius, to cover the posterior part of the capsule of the joint, and to be fastened to the external condyle. It is inserted, by a round tendon, into the inner and back part of the head of the tibia just below the joint. The unfavourable insertion of this muscle is compensated by the course of its fibres, which gives it great increase of strength. It flexes the leg on the thigh. MUSCLES. 421 muscles of the leg. These muscles are situated anteriorly, posteriorly, and externally. The Tibialis Anticus muscle is situated superfici- ally under the fascia of the leg, at the outside of the spine of the tibia, and in front of the interosseous ligament. It arises, fleshy, from the head of the tibia, from its outer surface, spine, and from the interosse- ous ligament to within three or four inches of the ancle. It also arises by its front surface from the? internal face of the fascia of the leg. A rounded long tendon is formed below, which passing through a distinct noose of the annular liga- ment in front of the maleolus internus, crosses the astragalus and os naviculare, and is inserted into the anterior part of the base of the cuneiforme inter- num, and into the adjacent part of the metatarsal bone of the great toe. It bends the foot, and presents the sole obliquely in- wards. The Extensor Longus Digitorum Pedis, is also superficially placed just under the fascia of the leg" and in front of the fibula, being in contact above with the tibialis anticus, and below with the extensor pro- prius pollicis. It arises, tendinous and fleshy, from the 428 OF THE LOWER EXTREMITIES. outer part of the head of the tibia, from the head of the fibula, and almost the whole length of its anterior spine; also from the upper part of the interosseous ligament and the internal face of the fascia of the leg. About the middle of the leg this muscle splits into four tendons, which are confined by the annular liga- ment of the ancle, and then diverging, are inserted into the base of each small toe, and expanded over its back part as far as the last phalanx. It extends all the joints of the small toes and flexes the foot. The Peroneus Tertius is rather an appendage of the extensor longus, is found at its lower outer part, and cannot be naturally separated from it. It arises from the anterior angle of the fibula, and extends between its middle and lower end. It is inserted, by a flattened tendon, into the base of the metatarsal bone of the little toe, and assists in bending the foot. The Extensor Proprius Pollicis Pedis is be- tween the lower parts of the tibialis anticus, and the extensor longus. It arises from the fibula between its anterior and internal angles, by a tendinous and fleshy origin, which commences about four inches be- low the head of the fibula, and continues almost to • its inferior extremity. A few fibres also come from MUSCLES. 429 the interosseous ligament, and from the lower part of the tibia. The muscle being half penniform, the fibres run obliquely to a tendon at its fore part, which passes under the annular ligament, and over the astragalus and scaphoides and upper internal parts of the foot, to be inserted into the base of the first and second phalanges of the great toe. On the outside of the leg, between the fibula and fascia, are the two Peronei muscles. The Peroneus Longus arises, tendinous and fleshy, from the fore and outside of the head of the fibula, from the space on its outer side above, between the external and anterior angles, also from its external angle to within a short distance of the ancle. A flattened thick tendon constitutes the outer face of the muscle, to which the fibres pass obliquely. This tendon is lodged in the groove at the posterior part of the malleolus externus, being confined to it by a thick ligamentous noose, and traverses the outer side of the os calcis, where its passage is marked by a superficial sulcus. It then runs through the groove of the os cuboides, and lying deep in the sole of the foot next to the tarsal bones, is inserted into the base of the internal cuneiform bone, and into the adjacent part of the metatarsal bone of the great toe. 430 OF THE LOWER EXTREMITIES. It extends the foot and inclines the sole obliquely outwards. The Peroneus Brevis is concealed in a great de- gree by the peroneus longus, being situated between the latter and the extensor longus digitorum. It arises, tendinous and fleshy, from the outer surface of the fibula,, commencing about one third of the length of the bone from its head, and continuing almost to the ancle. A tendinous facing exists externally also in this muscle, to which its fibres proceed obliquely. This tendon is continued through the fossa at the back part of the malleolus externus, being covered by the tendon of the peroneus longus, and confined by the same ligamentous noose, and passing through the superfi- cial fossa at the outer side of the oscalcis, is inserted into the external part of the base of the metatarsal bone of the little toe. It extends the foot and pre- sents the sole obliquely downwards. The Gastrocnemius is the most superficial mus- cle on the back of the leg, and conceals the others in consequence of its breadth. It arises from the con- dyles of the femur by two heads. One head arises, tendinous, from the upper back part of the internal condyle, and fleshy from the ridge leading to the li- nea aspera; the other head arises, by a broad ten- don in the same way, from the external condyle and MUSCLES 431 the line above it. A triangular vacancy is left be- tween the heads of the muscle for the passage of the popliteal vessels; they then join together, but in such a way that the appearance of two bellies is distinctly preserved, of which the internal is the largest. The muscular fibres pass from a broad tendinous facing on the back to a corresponding one on the front sur- face of the muscle, from the latter of which comes the Tendo Achillis. The heads of the gastrocnemius being detached from their origin, we then see the Soleus or Gastroc- nemius Internus. The Soleus arises, fleshy, from the posterior part of the head of the fibula and from the external angle of that bone for two-thirds of its length down, behind the peroneus longus. It also arises, fleshy, from the oblique ridge on the posterior surface of the tibia, just at the lower edge of the popliteus muscle, and from the internal angle of the tibia for four or five inches. The two heads are separated for the passage of the posterior tibial vessels. The body of this muscle has a great intermixture of tendinous matter in it, and from its lower extremity proceeds the other origin of the tendo achillis; about three or four inches above the heel this tendon joins the anterior face of the tendon of the gastrocnemius, and by the union of the two is formed the Tendo 432 OF THE LOWER EXTREMITIES. Achillis, which is inserted into the posterior inferior surface of the os calcis at its tubercles. These two muscles extend the foot, and are all-im- portant in walking. The Plantaris is a singular little muscle conceal- ed by the gastrocnemius, which has a short fleshy belly and a long tendon. It arises, fleshy, from the ridge of the os femoris just above the external con- dyle, passes across the capsular ligament of the joint, and adheres to it in its course; the belly terminates somewhat below the head of the tibia in a long deli- cate tendon which descends between the inner head of the soleus and the gastrocnemius. At the place where these tendons unite the tendon of the soleus emerges from between them, and, run- ning at the inner edge of the tendo achillis, is insert- ed into the inside of the os calcis just before the in- sertion of the tendo achillis. It extends the foot. The Popliteus is a triangular muscle on the back of the knee joint. It arises, by a thick round tendon, from a deep depression on the exterior face of the external condyle, passes through the capsular liga- ment, being connected with the external semilunar cartilage, and then forms a fleshy belly which passes obliquely inwards and downwards. It is inserted, fleshy, into the oblique ridge on the MUSCLES. 43$ back of the tibia just below its head, and into the tri- angular depression above it. It bends the leg, and when bent, rotates it inwards. By removing the soleus we expose three other mus- cles on the back of the leg, the Tibialis Posticus, the Flexor Longus Digitorium Pedis, and the Flexor Lon- gus Pollicis Pedis. These muscles are covered by a thick strong fascia, from which some of their fibres originate, and which should be removed. The Flexor Longus Digitorum Pedis Perfo- rans is behind the tibia, and at the inner edge of the tibialis posticus. It arises, by an acute tendinous and fleshy beginning, from the back of the tibia a little be- low the popliteus muscle, its origin being continued from the internal angle of the tibia almost to the an- cle joint. It arises also, by tendinous and fleshy fibres, from the outer edge of the tibia just above its connection with the fibula at the ancle, and between this double order of fibres the tibialis posticus lies. The fibres pass obliquely into a tendon at the pos- terior edge of the muscle which runs in the groove of the internal malleolus, and is confined there by a strong ligamentous sheath. The tendon then gets to the sole of the loot along the sinuosity of the os cal- cis, and, being joined by a considerable tendon de- tached from the flexor longus pollicis, it divides into 3 i 434 OF THE LOWER EXTREMITIES. four branches which are appropriated to the foul small toes. These tendons are inserted into the bases of the last phalanges of the lesser toes, are very near the tarsal bones, and, from perforating the tendons of the flexor brevis, correspond with the flexor perforans of the hand. This muscle flexes the small toes and extends the foot. The Flexor Longus Pollicis Pedis is a stout muscle formed of oblique fibres, situated on the back part of the fibula and at the outer side of the tibialis posticus. It arises by an acute tendinous and fleshy beginning from the posterior flat surface of the fibula, commencing about three inches from its head, and continuing almost to the ancle. The tendon of this muscle is large and round, it forms gradually, and constitutes a facing to the poste- rior edge of the muscle. It passes through a super- ficial fossa of the tibia at the back of the ancle near its middle, and from thence through a notch in the back edge of the astragalus to the sole of the foot, where it crosses the tendon of the flexor longus digi- torum, giving off the branch just mentioned to join it. This tendon is deeper seated in the foot than the other. The tendon of the flexor longus pollicis is inserted into the last joint of the great toe. It bends the great MUSCLES. 4S5 toe, and from its connection with the others will bend them also. The Tibialis Posticus is placed between, and concealed by the two last muscles. It arises, by a narrow fleshy beginning, from the front of the tibia, at the under surface of the process which joins it to the fibula, and then gets to the back of the leg through a hole in the interosseous ligament. It con- tinues its origin from the whole of the interosseous ligament, and from the surfaces of the tibia and fibula bordering on this ligament, excepting one-third of the lower part of the fibula, and rather more of the lower part of the tibia. The fleshy fibres run obliquely to a middle tendon which passes in the groove at the back of the malle- olus internus, and is inserted into the upper internal part of the os naviculare. This tendon also divides in^uch a way as to be inserted into the internal and external cuneiform bones, into the os cuboides, and os calcis. It extends the foot, and presents the sole obliquely inwards. OF THE MUSCLES OF THE FOOT. The Extensor Brevis Digitorum Pedis is the only muscle on the superior surface of the foot. It is placed beneath the tendons of the extensor longus, 436 OF THE LOWER EXTREMITIES and arises, tendinous and fleshy, from the fore upper part of the os calcis. It forms a short fleshy belly, which is partially divided into four parts; from these bellies proceed as many tendons, which crossing very obliquely the tendons of the extensor longus, are in serted into the great toe, and the three next toes by joining with the tendons of the extensor longus, which are spread over their backs. It extends the toes. The Sole of the Foot is protected, in the first place, by an unusual thickness of its cuticle, which is in- creased in such parts as are most pressed upon, as the heel, and the ball of the great toe. Beneath it, is a thick layer of adipose matter, found, in the most emaciated as well as the most corpulent subjects, which seems to be less under the influence of the causes producing a diminution or increase of fat, than the adipose matter in any other part of the body. It is collected into granulations separated from each other by processes of condensed cellular mem- brane resembling ligament, that pass from the inte- rior surface of the skin to the aponeurosis plantaris. It fills up completely all the fissures in this aponeu- rosis, and adheres very closely to it, so that it requires much trouble to get out a fair dissection of the apo- neurosis. The Aponeurosis, or Fascia Plantaris, is a liga- mentous membrane, extending from the tubercle of MUSCLES. 43*5 the os calcis, to the anterior ends of the metatarsal bones. It is triangular, and corresponds with the out- line of the foot, by being narrow behind, and broad before. It is divided into three parts, according to the division of the muscles of the foot, one part lying on the muscles at the outside of the sole, another on the muscles at the inside of the sole, and the third being between the other two. The internal and ex- ternal portions are thin, and reticulated; they extend from the tubercles of the os calcis to the roots of the internal and external metatarsal bones, and are scarcely seen beyond them. But the central portion is re- markably well expressed, it is thick behind near the heel, and diminishes in thickness as it spreads out. Anteriorly it is divided into five portions, one for each metatarsal bone; each of these portions is bifur- cated, and dips down to be inserted on each side of the metatarsal bone near its head. Between the prongs of each bifurcation pass the tendons, nerves, &c. to the toes. The interior face of this membrane affords origin to many of the muscular fibres, and from it proceed vertical partitions separating the muscles of the middle of the foot from such as are on each side of it. When the Aponeurosis Plantaris is removed, we see three muscles; the middle one under the large central portion of the aponeurosis, is the Flexor Brevis Digitorum Pedis, the outer is the Abductor 438 OF THE LOWER EXTREMITIES. Minimi Digiti, and the inner the Abductor Pollicis Pedis. The Flexor Brevis Digitorum Pedis arises, fleshy, from the tubercle of the os calcis by a narrow beginning, also from the interior surface of the apo- neurosis, and the tendinous septa between it and the contiguous muscles. It forms a fleshy belly going nearly as far forwards as the middle of the metatarsal bones, there it divides into four tendons, which go to the smaller toes. These are perforated by the tendons of the flexor longus, and are inserted into the sides of the second pha- langes. The tendon for tne little toe is often defi- cient. It bends the second joint of the toes. By detaching this muscle from its origin and turn- ing it down, we bring into view the tendon of the Flexor Longus Digitorum Pedis, and its attachments behind, to the tendinous slip from the Flexor Longus Pollicis, and to the Massa Carnea Jacobi Sylvii, or Flexor Accessorius, and before, to the Lumbricales muscles. The Flexor Accessorius is at the outside of the tendon of the flexor longus. It arises, fleshy, from the inside of the sinuosity of the os calcis, and, by a MUSCLES. 439 thin tendon, from the outside of the bone before its tubercle. It is inserted, fleshy, into the outside of the tendon of the flexor longus, just at its division into four ten- dons. Like a second hand at a rope, it assists in flex- ing the toes. The Lumbricales Pedis are four small tapering muscles which arise from the tendon of the flexor longus just after its division, or while it is in the act of dividing. One of them is appropriated to each lesser toe, and is inserted into the inside of its first phalanx, and into the tendinous expansion that is sent off from the extensor muscle to cover its dorsum. They increase the flexion of the toes and draw them inwards. The Abductor Pollicis Pedis arises, tendinous and fleshy, from the internal anterior part of the tu- berosity of the os calcis, from a ligament extended from the tuberosity to the sheath of the tendon of the tibialis posticus, from the internal side of the navicu- lar, and from the cuneiforme internum. It forms the internal margin of the sole of the foot, and is inserted, tendinous, into the internal sesamoid bone and into the base of the first phalanx of the great toe. It draws the great toe from the rest 440 OF THE LOWER EXTREMITIES. The Flexor Brevis Pollicis Pedis is situated iin~ mediately at the exterior edge of the abductor polli- cis. It consists of two bellies, separated by the ten- don of the flexor longus pollicis, which are parallel with each other; one is inseparably connected with the tendon of the abductor pollicis, and the other with the adductor pollicis. It arises, tendinous, from the under part of the os calcis, just behind its connection with the os cu- boides, and from the under part of the external cu- neiform bone. The internal belly is inserted, tendinous, into the internal sesamoid bone along with the tendon of the * abductor pollicis, and the external belly is inserted, tendinous, into the external sesamoid bone along with the tendon of the adductor pollicis. Each insertion is continued on to the base of the first phalanx of the great toe. It flexes the great toe. The Adductor Pollicis Pedis is situated at the outside of the flexor brevis, and is extended obliquely across the metatarsal bones. It arises, tendinous, at the external part of the foot, from a strong ligament which is stretched from the os calcis to the os cu- boides, and from the roots of the second, third, and fourth metatarsal bones. It is inserted, tendinous, into the external sesamoid bone, which insertion is continued to the first pha- MUSCLES. 441 lanx of the great toe, and is closely united to the ten- don of the external head of the flexor brevis pollicis. It draws the great toe towards the others. The Abductor Minimi Digiti Pedis forms the external margin of the sole of the foot, and is imme- diately beneath the aponeurosis plantaris. It arises, tendinous and fleshy, from the outer side of the tuber of the os calcis, and also from the exterior part of the base of the metatarsal bone of the little toe. It is inserted, by a rounded tendon, into the exte- rior part of the base of the first phalanx of the little toe. It draws the little toe from the other toes. The Flexor Brevis Minimi Digiti Pedis is just within the tendon of the abductor minimi digiti. It arises from the ligament which is extended from the tuberosity of the cuboid bone to the heads of all the metatarsal bones; also from the root of the fifth me- tatarsal bone. It is inserted, by a tendon, into the lower part of the first phalanx of the little toe at its base, and into the head of the metatarsal bone of the same toe. It bends the little toe. The Transversalis Pedis is placed beneath the tendons of the flexor muscles. It is small, and lies across the anterior extremities of the metatarsal bones. 3k 442 OF THE LOWER EXTREMITIES. It arises, tendinous, from the capsular ligament of the first joint of the little toe; it also arises from the capsule of the first joint of the next toe. It is inserted into the exterior face of the common tendon of the adductor and flexor brevis pollicis at the external sesamoid bone. It approximates the heads of the metatarsal bones. The Interosseous Muscles are seven in number, four of which may be seen on the upper surface of the foot. There are two to the first small toe, two to the second, two to the third, and one to the fourth or little toe. The muscles seen on the upper side of the foot are for the most part double headed, that is, they arise from the contiguous surfaces of the meta- tarsal bones. The Interosseus Primus Digiti Primi Pedis, or the Abductor Indicis Pedis, is seen superiorly. It is placed between the metatarsal bone of the great toe and the first small toe, and arises, fleshy, by a double head, from the opposed surfaces of their roots. It is inserted, tendinous, into the inside of the root of the first joint of the first small toe, and pulls it in- wards. The Interosseus Secundus Primi Digiti, or the Adductor Indicis Pedis, is also external or above. It is situated between the metatarsal bones of the first MUSCLES. 443 and second small toes, arising from the opposed sur- faces of their roots by a double fleshy and tendinous head. It is inserted into the outside of the first phalanx of the same toe by a tendon. It draws this toe out- wards. The Interosseus Primus Secundi Digiti Pedis, or the Abductor Medii Digiti, is at the bottom of the foot, and arises from the inside of the metatarsal bone of the second small toe. It is inserted into the inside o'f the first phalanx of the second toe. It draws this toe inwards. The Interosseus Secundus Digiti Secundi, or the Adductor Medii Digiti, is seen at the upper part of the foot, between the second and third meta- tarsal bones of the lesser toes, arising from the op- posite surfaces of their roots. It is inserted, tendinous, into the outside of the base of the first phalanx of the second small toe. It draws this toe outwards. The Interosseous Primus Digiti Tertii, or the Abductor Tertii Digiti, is in the sole of the foot. It arises from the inside of the metatarsal bone of the third toe near its not, and is Inserted, tendinous, into the inside of the base of 444 OF THE LOWER EXTREMITIES. the first phalanx of the third toe. It draws this toe inwards. The Interosseus Secundus Digiti Tertii, or the Adductor Tertii Digiti, is seen on the upper surface of the foot, occupying the interval of the me- tatarsal bones of the third and fourth small toes, and arises, by a double head, from the opposite surfaces of their roots. It.is inserted, tendinous, into the outside of the root of the first phalanx of the third small toe. It draws this toe outwards. The Interosseus Digiti Minimi is on the under surface of the foot. It arises from the inside of the base of the metatarsal bone of the fourth small, or the little toe, and is Inserted, tendinous, into the inside of the first phalanx of the little toe. It draws this toe inwards. It is also called, Abductor Minimi Digiti Pedis; but this name, has rather a tendency to confuse, as one of the muscles, as stated, on the outer side of the sole of the foot, has the same name. V BLOOD-VESSELS. 445 Section II. of the blood-vessels of the lower extremities, The Femoral Artery, (Arteria Femoralis,) is a continuation of the external iliac. It appears first on the thigh, half-way, or nearly so, between the sym- physis pubis and the anterior superior spinous process of the ilium; emerging from beneath Poupart's liga- ment, it is there only covered by the skin and fascia of the part, having the femoral vein at its inside, and the trunk of the anterior crural nerve, about half an inch from it on the outside. It lies upon the belly of the psoas magnus muscle, crosses the pectinalis, and the whole of the insertion of the adductor longus mus- cle, and about one-third of the length of the thigh bone from below, it penetrates the insertion of the adductor longus and gets to the ham, being then behind the leg. For the upper third of its course the femoral artery is at the inner edge of the rectus femoris, and but a lit- tle distance from it, it then inclines inwards and occu- pies the angle formed by the contact of the vastus in- ternus, and the adductor longus. Above, the sartorius is at its outside; but as this muscle inclines very ra- pidly inwards, immediately after its origin, it in a lit- tle time begins to pass along the external margin of the artery, and shortly afterwards covers the artery com- 446 OF THE LOWER EXTREMITIES. pletely to the place where it penetrates the adductor. Where the artery lies in the angle formed by the ad- ductor longus, and the vastus internus, it is covered by a strong interlacement of tendinous fibres from the muscles, and is also enveloped by its own cellular coat. To cut upon the femoral artery in any part of its course, lay the subject horizontally, and turn the leg outwards, so that the external margin of the sole of the foot will be in contact or nearly so with the table. A line drawn then from midway between the anterior superior spine of the ilium, and the symphysis pubis, to the centre of the internal condyle of the os femoris, will be precisely over it. The following branches come from the Femoral Artery. 1. The first is called by Haller, Arteria Ad Cutem Abdominis. From this a branch is sent upwards to- wards the umbilicus under the skin, and one more to supply the inguinal glands. 2. The External Pudic, (PudewdaeExternae,) two or three in number; they are sent to the integuments and lymphatic glands of the groin, also to the skin of the penis and scrotum, or to the labia externa. One of these trunks arises from the upper internal part of the femoral artery, and the other sometimes from the profunda. BLOOD-VESSELS. 447 The arteries as yet mentioned, anastomose freely with each other, are irregular in their number,size, and origin, but for the most part do not exceed the size of a common knitting needle. 3. The Profound Artery, (Profunda Femoris,) is very happily called, in consequence of its distribu- tion, by Professor Chaussier, La Grande Musculaire De La Cuisse. It is almost equal in size to the femo- ral itself, and arises from its posterior part on a level with the trochanter minor. It almost immediately begins to give off branches externally and internally, but the main trunk of the artery continues for seve- ral inches in contact with the femoral artery or nearly so, and beneath it. It then terminates gradu- ally by branches which penetrate to the back of the thigh. The profunda femoris is distributed as follows: a. The External Circumflex, (Circumflexa Ex- terna,) arises from its external superior part, some- times, however, from the femoral itself; it passes out- wards under the sartorius and the rectus femoris, and divides into two secondary branches. The superior and shorter of these is distributed to the parts about the trochanter major, as the anterior edges of the gluteus medius and minimus, the capsule of the hip joint, and the heads of the extensor muscles. The second goes along the outside of the thigh to the pa- 448 OF THE LOWER EXTREMITIES. tella, and is about the size of a crow-quill. It first passes obliquely between the rectus and the crureus, and then vertically under the anterior margin of the vastus externus, between it and the crureus till it ter- minates about the knee, anastomosing with the articu- lar arteries, being, however, principally distributed to the crureus and vastus externus. b. The Internal Circumflex, (Circumflexa In- terna,) arises from the inner side of the profunda, just below the external circumflex, but sometimes it also comes from the femoral. It is somewhat under the size of the other, and penetrates between the psoas magnus and pectinalis; it winds around the internal side of the neck of the os femoris, and divides into two branches which supply the contiguous parts, as the heads of the muscles and the joint. c. Several ramifications are also sent from the pro- funda to supply the anterior faces of the adductor muscles; they are irregular in number, size, and place of origin, and have no appropriated names. d. The Perforating Arteries* (Rami Profundi Perforantes,) three or four in number, are given off successively, are numerically named, and all penetrate the adductor muscles near the thigh bone to get to the back of the thigh. The first arises immediately below the little tro- BLOOD-VESSELS. 449 chanter, and gets through the adductor magnus just below the quadratus femoris, being distributed about the heads of the hamstring muscles. The second penetrates the adductor magnus at the lower part of the insertion of the gluteus maximus into the linea aspera, being distributed about there and to the corresponding section of the long head of the biceps flexor cruris. The third penetrates the adductor magnus a little below the commencement of the origin of the short head of the biceps, being distributed thereabouts. The fourth penetrates the adductor magnus about an inch and a half above the hole for the femoral ar- tery, being distributed to the neighbouring part of the adductor and to the hamstring muscles. After the origin of the profunda, the femoral artery gives off three or four twigs the size of a large knit- ting-needle, which are disposed of, upon the sartorius, adductors, vastus internus, and integuments, but they are too irregular in number, origin, and course for systematic description. The Anastomosing Artery, (Arteria Anastomo- tica,) the last branch of the femoral, is sent from it just before it enters the aperture in the adductor mag- nus. This artery descends, in the course of the ten- don of the adductor, to the knee, in front of the ten- don, between it and the vastus internus muscle. It is distributed to the parts lying along its course. Sl 150 OF THE LOWER EXTREMITIES. The Popliteal Artery, (Arteria Poplitaea,) is thi continuation of the femoral after the latter has passed through the adductor tendon, and extends from this point to the opening in the interosseous ligament of the leg, just below the heads of the bones. Its first act is to cross obliquely the os femoris as far as its middle; it then passes in a vertical line downwards, very nearly over the centre of the os femoris, knee joint, and head of the tibia, being only separated from these parts in consequence of a thick envelop of fat, filling up the hollow of the ham, which protects the artery from the effects of sudden flexions of the part and of bruises. The popliteal artery sends off the following branches: 1. The Superior Internal Articular Artery, (Arti- cularis Superior Interna,) sometimes exists as two trunks; it arises just above the internal condyle, per- forates the adductor tendon, and, going horizontally, is spent on the inner side of the joint above. 2. The External Superior Articulating Artery. (Articularis Superior Externa,) arises just above the external condyle, passes horizontally between the fe- mur and the biceps flexor, and is distributed to the up- per external parts of the joint. 3. The Middle Articular, (Articularis Media,) some- times comes from one of the others; it is distributed to the posterior middle parts of the knee joint. 4. The Internal Inferior Articular Artery, (Articu- laris Inferior Interna,) arises on a level with the infe- BLOOD-VESSELS. 451 rror part of the internal condyle. It descends ob- liquely, passes between the lateral ligament and the head of the tibia, and then mounts towards the patella, being distributed in numerous branches. 5. The External Inferior Articular Artery, (Arti- cularis Inferior Externa,) arises on a level with the last, and sometimes they are derived from a common trunk. It passes between the external lateral liga- ment and the head of the tibia, mounts afterwards to- wards the patella, and is then minutely ramified on the lower external parts of the knee joint. The upper articular arteries anastomose with the lower, and also with the anastomotic and the long branch of the external circumflex. Below the knee, the popliteal artery is over the po- pliteus muscle and between the heads of the gastroc- nemius. Here it sends off a large branch to each head of the gastrocnemius muscle, and small irregu- lar branches to the other muscles, and sometimes the nutritious artery of the tibia. On a level with the aperture of the interosseous ligament, the popliteal artery may be considered as terminating by a division into two large branches, the Anterior Tibial, and the Posterior Tibial. The Anterior Tibial Artery, (Tibialis Anterior,) after getting through the interosseous foramen, passes down the leg in front of the interosseous ligament and in contact with it, it passes also over the middle 452 OF THE LOWER EXTREMITIES. of the ancle joint to the dorsum of the foot, and is continued in a straight line to the interval between the metatarsal bones of the great toe, and the one next to it. This artery is situated under a line drawn from the middle anterior part of the head of the fibula, to the middle of the ancle joint in front, and is continued in the course of a line drawn from this latter point to the junction of the two first me- tatarsal bones. Above, it is placed between the tibialis anticus and the extensor longus digitorum; below, on the leg between the extensor pollicis and the tibialis anticus; and while engaged with the tendons of the muscles under the annular ligament of the joint, it gets to the fibular side of the tendon of the extensor pollicis. The anterior tibial artery gives off'several branches. 1. The Recurrent Tibial, (Tibialis Recurrens,) penetrates the head of the tibialis anticus muscle, and is distributed about the exterior and anterior part of the head of the tibia, and of the patella. Several small arterial twigs are then sent to the muscles and periosteum on the fore part of the leg, but they have no name. 2. The Internal Malleolar, (Malleolaris Inter- na,) arises from the anterior tibial somewhat above the joint, it passes under the tendon of the tibialis BLOOD-VESSELS. 453 anticus, and is distributed to the internal ancle, and the contiguous part of the foot. 3. The External Malleolar, (Malleolaris Ex- terna,) exists most commonly as two small branches, one arising on a level with the joint, and the other an inch or two above, which pass beneath the tendons of the extensor communis and the peroneus tertius, to the lower part of the fibula, and inosculate with the peroneal artery. 4. The Tarsal Artery, (Arteria Tarsea,) arises from the anterior tibial just below the ancle joint, it runs outwardly under the tendons and the belly of the extensor brevis, being distributed to the upper outer part of the tarsus. 5. The Metatarsal Artery, (Arteria Metatar- sea,) arises just below the last, and is distributed by many branches on the upper part of the metatarsus. A successful injection demonstrates an artery in each interosseous interval of the metatarsal bones above, which comes from the metatarsal. 6. The Dorsal Artery of the Great Toe, (Dor- salis Hallucis,) arises from the anterior tibial at the root of the first metatarsal bone, it runs in the supe- rior part of the first metatarsal interval, and termi- 454 OF THE LOWER EXTREMITIES. nates in two branches which go to the opposed faces of the great toe, and the second toe. After this the anterior tibial artery sinks down and joins the external plantar in the sole of the foot. The Posterior Tibial Artery, (Tibialis Posti- ca,) extends from the head of the tibia to the hollow of the os calcis; it is on the tibial side of the leg, and is placed between the soleus posteriorly, and the flexor longus digitorum anteriorly, and beneath the fascia of the part. It is distributed in the following manner. 1. The Peroneal Artery, (Arteria Peronea,) arises a little below the commencement of the poste- rior tibial, and is extended from the inferior edge of the popliteus muscle to the external ancle. It is placed at the tibial edge of the fibula, between the flexor longus pollicis muscle, and the external edge of the tibialis posticus. Its situation is therfore deep and of difficult access in the living body. After de- scending along two thirds of the fibula, it divides into anterior and posterior branch. The first traverses the interosseous ligament, and descending in front of it, is ramified on the upper external part of the foot. The second descends posteriorly along the fibula, and is distributed about the peroneo-tibial articulation and the adjacent parts. BLOOD-VESSELS. 455 2. Several small irregular muscular and cutaneous branches afterwards arise from the posterior tibial, and at its upper part the Arteria Nutritia Tibiae, most commonly. At the ancle the posterior tibial is between the in- ternal edge of the tendo achillis and the tibia, still confined by the fascia of the part. It passes to the sole of the foot in the hollow of the os calcis, between the bone and the abductor muscle of the great toe. At the ancle it is on a line with the internal margin of the joint behind, and in contact with the posterior malleolus, between the tendon of the flexor longus pollicis and that of the tibialis posticus. Having got to the sole of the foot it terminates by dividing into two branches, the Internal and External Plantar Ar- teries. The Internal Plantar, (Plantaris Interna,) is the smaller of the two; it is covered by the abductor pollicis, and passing between it and the internal in- ferior margin of the foot, it terminates at the ante- rior end of the first metatarsal bone in the internal digital artery of the great toe. In this course it sends several branches to the contiguous parts, which give them a high degree of vascularity. One of the most remarkable is given off about the os scaphoides and cruizes along the internal margin of the abductor pollicis to its anterior end. Another makes its ap- 456 OF THE LOWER EXTREMITIES. pearance superficially in the sole of the foot, in the fissure between the abductor pollicis and the flexor brevis digitorum, and goes as faT forward as the other. The External Plantar, (Plantaris Externa,) in- clines towards the outer margin of the foot between the flexor brevis digitorum and the flexor accessorius, it then advances at the internal edge of the abductor minimi digiti to the root of the metatarsal bone of the fourth toe, and makes a curvature forwards and in- wards between the tendons of the flexor longus and the metatarsal bones to the first metatarsal interval, where it is joined by the anterior tibial artery from above. This sweep forms the plantar arch (arcus plantaris). The distribution of the internal plantar is as fol- lows. a. Half an inch from its origin it detaches a multi- fidous branch backwards and outwards to the inferior and to the external parts of the heel, which also sends an arteriole along the external edge of the abductor minimi digiti. b. At the root of the fourth metatarsal bone a branch arises, called the External Plantar Artery of the Little Toe, which goes first along the internal mar- gin of the muscles of this organ, and afterwards at the head of its metatarsal bone, gets between them and the bone, and is distributed along the external margin of the little toe. c. The Digital Arteries come next, which arise sue- BLOOD-VESSELS. 457 cessively at the fourth, third, second, and first meta- tarsal intervals, or near them, from the convex side of the plantar arch. They get forward between the transversalis pedis and the interosseous muscles, and, arriving at the roots of the toes, each artery bifurcates and goes to the opposed sides of the adjacent toes, like the corresponding arteries of the hand. The digital artery that supplies the great toe and the opposite side of the toe next to it, is derived from the united trunks of the anterior tibial and the exter- nal plantar. At the head of the metatarsal bone it detaches a branch which runs along the inner edge of the great toe, and is united, by anastomoses, with the internal plantar artery. OF THE VEINS OF IHE LOWER EXTREMITIES. These veins are superficial and deep-seated. The more important of the first are the Saphena Major and the Minor. 1. The Great Saphena arises from the inside of the foot, about the great toe and from its sole; it passes in front of the internal ancle, along the inside of the leg, over the internal condyle of the femur, along the inner front part of the thigh, and terminates in the fe- moral vein just below Poupart's ligament. As it as- cends it collects branches from the anterior and pos- 3 m 458 OF THE LOWER EXTREMITIES. terior parts q/ the lower extremity. It may be seen very readily in the living subject beneath the skin. 2. The Saphena Minor is also readily seen through the skin. It arises from the external superior parts of the foot, passes behind the external ancle, and as- cends on the outside of the leg to the ham, receiving • contributions in its course; here it crosses the exter- nal head of the gastrocnemius muscle, and, dipping nto the ham, empties into the popliteal vein. Frequent anastomoses occur between the saphena major and minor. The origin and course of the femoral veins are so similar to the distribution and course of the femoral artery, that a description is needless. A venous tube always attends an arterial one, being in contact with it, enclosed in the same sheath, and called by the same name. The smaller arterial branches in the leg and thigh have each two veins called Venae Comites. The relative situation of the large venous trunks is, important. At Poupart's ligament the femoral vein is at the inside of the artery; at the passing of the ad- ductor tendon, the vein is nearest the thigh bone; and in the ham, the popliteal vein is behind the artery and consequently more superficial. NERVES. 459 Section III. OF TH^ NERVES OF THE LOWER EXTREMITIES. The Nerves of the Lower Extremity are derived from that part of the medulla spinalis which is situat- ed in the lumbar vertebrae and in the sacrum. The lumbar nerves form a plexus behind the psoas mag- nus muscle, from which proceeds a cluster of nerves to supply the front part of the lower extremity, in- cluding both its skin and muscles. The sacral nerves form a plexus in the pelvis at the side of the rectum, fljpm which proceeds the largest nerve in the body, the Sciatic, appropriated to the supply of the skin and muscles on the back part of the lower extremity. The lower part of the lumbar plexus is continued into the upper of the sciatic or sacral, so that, under a more general classification than what is adopted, both of these plexuses may be considered as forming but one. The Plexus Lumbalis is seen by dissecting the psoas magnus muscle from its origin and turning it aside; the primitive nerves, constituting this plexus, sometimes pass through the substance of the muscle instead of going behind it. The plexus is formed by the four upper lumbar nerves with a filament from the last dorsal. The anterior branches only of these 4C0 OF THE LOWER EXTREMITIES. nerves are concerned in forming it, as the posterior branches all go to the muscles of the back. In the distribution of this plexus to the lower ex- tremity, it will be seen, shortly after the commence- ment of the dissection, that its branches may be con- sidered under two divisions; first, such as go to the skin, and secondly, such as go to the muscles. From the upper part of the plexus fibrillae pass out- wards and downwards over the quadratus muscle; some of their ramuscules are spent on the sides of the abdominal muscles; others wind over the crista of the ilium about its middle part and are distributed to the integuments of the hip. The Spermaticus Externus arises also from the upper part of this plexus; it crosses the iliacus internus muscle, shaping its course towards the ante- rior superior spinous process of the ilium. Here it involves itself in the edge of abdominal muscles, and, going on the posterior face of Poupart's ligament, at the internal abdominal ring it joins the spermatic cord of the male, or the round ligament of the uterus of the female. In the first case it is distributed to the sper- matic cord and scrotum; in the second to the labia externa and mons veneris. The Cutaneus Externus arises from the lumbar plexus below the external spermatic. It passes across NERVES. 461 the iliacus internus towards the anterior superior spi- nous process about an inch below the spermaticus externus, and crosses the latter nerve just at that pro- cess. Emerging from the abdomen, by penetrating the commencement of Poupart's ligament, it is distri- buted, in several branches, to the integuments of the vastus externus muscle and along the edge of the rectus femoris; one of the latter extends to the pa- tella. The Cutaneus Medius is given from the anterior crural, an inch or so above Poupart's ligament, com- ing from it, among the cluster of branches which arise there to be distributed to the iliacus internus muscle and to the muscles of the thigh. It appears superfi- cially on the thigh, for the first time, by penetrating the sartorius muscle, about the internal edge of the rectus femoris; it descends then along the same edge of the latter muscle, and is distributed to its integu- ments. It does not descend so low as the other nerve. The Cutaneus Anterior arises also from the cru- ral nerve: it is on the inner side of the cutaneus me- dius, emerges from the fascia of the thigh, and crosses the sartorius muscle two or three inches below the cutaneus medius. It is distributed on the integuments of the vastus internus muscle, and some of its branches extend to the internal edge of the patella. 462 OF THE LOWER EXTREMITIES. The Cutaneus Internus arises from the anterior crural nerve among the same cluster above Poupart's ligament. It divides into four or five branches of different lengths, and is distributed to the integu- ments of the adductor muscles and along the inner front side of the thigh. One branch observes, very much, the course of the tendon of the adductor mag- nus, and reaches as far down as the inner side of the knee. The Cruralis Anterior arises from the middle nerves of the lumbar plexus; at first it is beneath the psoas magnus muscle; it then gets to its outside and passes from the abdomen, under Poupart's liga- ment, about half an inch from the femoral artery on its outside. Before it Teaches Poupart's ligament it gives off a cluster of nerves, several of which go to the iliacus internus muscle, others form the superfi- cial or cutaneous nerves of the thigh, and others the deep-seated or muscular branches. The distribution of the cutaneous nerves has just been mentioned; the muscular ones supply the adductor muscles, the four extensors, the pectineus, the sartorius, and the gra- cilis. One of the branches of the anterior crural nerve is seen to accompany the femoral artery, till the artery penetrates the adductor magnus; it then runs along the front margin of the tendon of the adductors in a theca formed by this tendon and the origin of the NERVES. 463 vastus internus. The nerve alluded to is the Saphe- nus; it passes afterwards between the internal con- dyle of the femur and the sartorius muscle, attaches itself to the saphena vein, and is distributed to the in- teguments of the inner side of the leg and of the up- per internal parts of the foot. The Nervus Obturatorius is. derived from the middle of the lumbar plexus also, and has very much the same position in regard to the psoas magnus as the anterior crural nerve. It descends into the pelvis from beneath the psoas magnus near the sacro-iliac suture, and passes forwards and downwards to the obturator foramen, having got through which, it divides into an anterior and a posterior branch. The first is distri- buted to the heads of the adductor longus and brevis, and to the gracilis and integuments. The second terminates in the obturator externus, and the adduc- tor magnus. The Sciatic Plexus, (Plexus Ischiadicus,) is formed by the union of the last lumbar with the four upper sacral nerves; the last lumbar, before it joins the plexus, receives the branch of the fourth lumbar nerve, which is left after the lumbar plexus is formed. This plexus is situated at the side of the rectum be- fore the pyramidalis muscle. The sacral nerves amount to six in number, sonle- times only to five. They arise from the lower part of 464 OF THE LOWER EXTREMITIES. the cauda equina, and pass in a very oblique direction in order to arrive at the sacral foramina. Like the other nerves of the spine they form ganglions by the union of their anterior and posterior fasciculi, and then pass outwards from the spinal canal, each one by an an- terior branch which goes through the foramen in front of the sacrum, and a posterior branch much smaller, which gets through the foramen on the back of the sacrum. The volume of the posterior branches in- creases till the fourth, but the fifth and the sixth are much smaller, in fact only fibrillae. These posterior branches all communicate with each other, being distributed to the heads of the sacro-lumbalfs and lon- gissimus dorsi, to the posterior edge of the gluteus magnus, to the integuments of the buttock, margin of the anus, arid to the internal parts of the thigh. The anterior branches of the sacral nerves are much larger than the posterior. The four first communicate with the sacral ganglions of the great sympathetic, besides forming the ischiatic plexus. The third and the fourth, assisted by the sympathetic, form the hypogastric plexus. The fifth, and the sixth when it exists, are distributed to the coccygeus, sphincter, and levator ani.* * This is only given as the most frequent arrangement of the sciatic plexus, and of the branches of nerves which proceed from it; other arrangements will often be met with in the cavity of the pelvis, in which not so many sacral nerves are sent to NERVES. 465 The Small Sciatic Nerve, (Nervus Ischiadicus Alter,) is the first considerable branch from the sciatic plexus, arising from its upper part by branches from the two first sacral nerves. It sends off the following branches. a. Nervi Glutaei, one passing through the upper part of the sciatic notch along with the artery to the glutaeus medius and minimus, the other below the py- riformis muscle to the glutaeus magnus. b. Nervus Pudendalis Longus Inferior, which passes under the tuber of the ischium to the glutaeus magnus, perineal muscles, urethra and integuments of the penis, and scrotum in men, and to the inferior parts of the labia externa in women. c. Ramus Femoralis Cutaneus Posterior. This nerve is placed between the integuments of the thigh, and the muscles which arise from the tuberosity of the ischium. It sends many branches successively to the skin on the back of the thigh; one of its branches longer than the others goes down to the ham, and there divides into several filaments which are distri- buted to the integuments on the back of the leg. The Nervus Pudendalis Superior comes from the third and fourth sacral, occasionally receiving a contribution from the small sciatic. It goes in com- the plexus, and the several branches proceeding from it, depart in a different manner. 3n 466 OF THE LOWER EXTREMITIES. pany with the internal pudic artery between the sa- cro-sciatic ligaments, and then divides into two branches; the inferior of which is distributed to the integuments and muscles of the perineum, to the urethra and scrotum; the superior passing along the ramus of the ischium and pubis with the trunk of the internal pudic artery, is distributed to the obtu- rator internus, accelerator urinae, urethra, and after- wards getting between the symphysis of the pubis and the penis, terminates on its integuments and the glans penis. The Nervus Ischiadicus, or the Great Sciatic, is the common trunk formed from the sciatic plexus; it is much the largest nerve in the body, and passes from the pelvis between the pyriformis and the ge- minus superior. It crosses vertically the small rota- tor muscles of the thigh, being concealed by the in- ferior edge of the glutaeus magnus; it is there about half-way between the tuberosity of the ischium and the trochanter major. Thence it descends on the back of the adductor magnus at the outer edge of the long head of the biceps flexor cruris. About half-way down the thigh, sometimes a little lower, the Sciatic nerve divides into the Popliteal or Posterior Tibial, and Peroneal nerves. Occasionally this division7 takes place as high as'the exit of the nerve from the pelvis, but in this case the fasciculi are parallel with each other as far as the middle of the thigh. From NERVES. 467 the trochanter minor to its usual place of division, this nerve is parallel with, and on the back of the thigh bone, but there the two branches begin to di- verge. The popliteal nerve continues straight down- wards to the back and middle of the knee joint, and to the interstice between the heads of the gastrocnemii muscles, whereas the fibular nerve goes along the in- ner posterior edge of the biceps flexor cruris, and passes between its tendinous insertion and the exter- nal head of the gastrocnemius muscle. In this course the following branches are sent from the sciatic: Twigs to the little rotator muscles of the thigh. The Cutaneus Internus Superior, which arises near the upper part of the thigh, and is distributed to the skin of the corresponding part. The Cutaneus Internus Inferior, which arises just below the last, and descending upon the inner head of the gastroc- nemius externus, is distributed to the integuments of the calf of the leg. A large trunk, and sometimes instead of it, distinct branches which go to the Adduc- tor Magnus, Semimembranosus, Biceps and Semiten- dinosus. The Peroneal Nerve, (Nervus Peroneus,) at the head of the fibula divides into two branches, the Pe- roneus Externus and the Tibialis Anterior; but be- fore this division it sends a small branch to the ex- ternal parts of the knee joint and two cutaneous 468 OF THE LOWER EXTREMITIES. branches called Peroneo-Cutaneous. The internal of the Peroneal Cutaneous descends behind the exter- nal head of the gastrocnemius, and at the bottom of the leg is united to a division of the posterior tibial called the External Saphenus or Communicans Tibiae. The external branch of the peroneo-cutaneous is dis- tributed to the skin along the fibula. The External Peroneal Nerve, (Peroneus Exter- nus,) gets between the head of the peroneus longus and the fibula, then between the peroneus longus and the extensor longus digitorum; it descends at the outer edge of the last muscle to the inferior third of the leg, giving out, in the mean time, many muscular branches. Here it penetrates the aponeurosis and divides into subcutaneous branches, which supply the lower part of the leg and the upper surface of the foot and toes. This nerve is called, by the French, the Musculo Cu- taneous of the leg. The Anterior Tibial Nerve, (Tibialis Anterior,) gets obliquely between the fibula, the peroneus longus, and the extensor longus digitorum to the front of the interosseous ligament, where it accompanies the ante- rior tibial artery. It passes with the artery under the annular ligament of the ancle, and has its terminating filaments going to the muscles and integuments of the upper surface of the foot as far as the end of the two first toes. One of its branches sinks down with the anterior tibial artery to the sole of the foot. High up in the leg it gives filaments to the knee joint, and, in NERVES. 469 its course downwards, it furnishes the muscles on the front of the leg. The Popliteal Nerve, (Nervus Popliteus,) having the direction mentioned, is placed between the skin and the popliteal vein. It gets between the heads of the gastrocnemii muscles and perforates the origin of the soleus, going with the posterior tibial artery be- tween this muscle and the flexor longus digitorum to the bottom of the leg. It gives off a. The External Saphenus, (Saphenus Externus or Communicans Tibiae,) which arises above the knee joint, and, descending between the skin and the gas- trocnemius, turns outwardly and anastomoses with the cutaneous branch alluded to of the peroneal nerve. The common trunk passes behind the external ancle, along the external margin of the foot, and terminates on the two last toes, having given off a great number of cutaneous branches. b. Branches to the heads of the gastrocnemius, so- leus, plantaris, and popliteus. c. Branches to the flexor longus digitorum, tibialis posticus, and to the flexor longus pollicis pedis. d. A branch through the interosseous ligament' above to the tibialis anticus. e. At the inferior part of the leg many cutaneous filaments, one of which gets to the sole of the foot. The Posterior Tibial Nerve, having given off these 470 OF THE LOWER EXTREMITIES. branches, divides in the hollow of the os calcis int© Internal and External Plantar Nerves. The Internal Plantar, (Plantaris Internus,) pro- ceeds along side the tendon of the flexor muscle of the great toe and the flexor longus and gives filaments to the contiguous muscles. It then divides in such a way as to furnish the two sides of the three first toes and the internal side of the fourth. The External Plantar, (Plantaris Externus,) proceeds with the artery of the same name to the outer edge of the foot between the flexor brevis digi- torum and the flexor accessorius. It is distributed to the two sides of the little toe and to the external side of the fourth toe. One branch penetrates to the in- terosseous muscles and to the transversalis pedis. A branch of considerable size is detached near the heel to the muscles and integuments connected with the os calcis. PART III. CHAPTER III. Of the Ligaments, Section I. OF the ligaments of the head and spine, Articulation of the Lower Jaw. The condyle of the lower jaw is invested by a capsular ligament which arises from the margin of the glenoid cavity of the temporal bone, and the front edge of its tuber- cle, and is inserted into the place where the condyle and neck of the lower jaw unite. This ligament has an accumulation of fibres internally and externally, which gives the joint the appearance of lateral liga- ments. By cutting open the capsular ligament, we shall see that a moveable cartilage is interposed between the glenoid cavity and the condyle, having its upper and under surfaces accommodated to the opposite articu- lar surfaces of these parts. There are also two dis- 472 OF THE LIGAMENTS. tinct synovial membranes, one passing from the move- able cartilage to the glenoid cavity, and the other from the lower surface of the cartilage to the condyle. The moveable cartilage is also attached by its circum- ference to the internal face of the capsular ligament The Stylo Maxillary Ligament is seen here, which runs from the styloid process, to the angle of the lower jaw, where it is inserted between the mas- seter and the internal pterygoid muscles. Also a small round ligament which goes from the styloid pro- cess to the appendix of the os hyoides. the ligaments of the spine. There is a capsular ligament with its synovial membrane, which surrounds the superior oblique pro- cess of the first vertebra, and is inserted into the root of the corresponding condyle of the os occipitis. A circular ligament arises from the whole supe- rior margin of the first vertebra, and is inserted into the margin of the great occipital foramen. The Occipito-Dentatum Ligament passes from the point of the processus dentatus, and is inserted into the anterior part of the margin of the occipital fora- men* ^ HEAD AND SPINE. 473 The two Moderator or Lateral Ligaments, one on each side from the lateral margin of the processus dentatus, and inserted into the corresponding surfaces of the first vertebra, and into the inner margin of of the foramen magnum. The Transverse Ligament which subtends the cavity in the first vertebra for the reception of the pro- cessus dentatus. The upper edge of this ligament is fixed to the foramen magnum, and the lower edge into the root of the processus dentatus. It keeps this process in its place. On each side there is a loose capsular ligament with its synovial membrane passing between the con- tiguous oblique processes of the first and second ver- tebrae. Between the bodies of all the vertebrae except the first and second, a ligamento-cartilaginous matter is placed, which is fixed to their bodies, and is a very potent means of union. This substance is more fibrous and hard externally, but near its centre it is of a pulpy consistence. A horizontal cut seems to demonstrate it as formed of concentric fibres, but there are also many others whose course is oblique, and irregular. The central pulpy part is confined by the other, and also in a state of compression, it makes So 474 OF THE LIGAMENTS. an articulation in some degree equivalent to the ball and socket joint. The Anterior Vertebral Ligament extends from the second vertebra to the sacrum. It consists of longi- tudinal white fibres, and is placed on the convex fore part of the spine. It adheres very closely to the intervertebral substance, and sends off processes on each side to fix it more securely to the bodies of the vertebrae. Where much motion is admitted, as in the neck and the loins, it is thinner than on the dorsal vertebrae. The Posterior Vertebral Ligament is in the spinal cavity. It arises from the edge of the foramen mag- num, and passes down to the sacrum on the posterior surface of the bodies of all the vertebrae, adhering to them and to the intervertebral substance. It is nar- rower on the bodies of the vertebrae than on the in- tervertebral snbstance. The Yellow Ligaments; there are twenty three pairs of them. They pass between the adjoining ver- tebrae one on each side, between the spinous and ob- lique process, and are best seen from the inside of the vertebral cavity. The first pair passes from the bony bridges of the second vertebra to that of the third, and so on successively to the sacrum. They are very elastic. THORAX. 475 Ligamentous fibres pass also between the spinous processes, and there are others between the trans- verse processes. The Ligamentum Nuchae is a tendinous septum beginning at the spinous process of the seventh cer- vical vertebra, and running up to the occiput, where it is fixed into its vertical ridge. It is connected in- termediately to the spinous processes of all the verte- brae above the seventh, so that it forms a partition be- tween the muscles of the two sides of the neck. All the Oblique Processes have their capsular and synovial membranes. Section II. LIGAMENTS OF THE THORAX. The heads of the ribs and their tubercles are fur- nished with capsular and synovial membranes uniting them with the corresponding articular surfaces of the vertebrae, and admitting of motion. The Ligamenta Transversaria Interna arise from the inferior surface of each transverse process, and are inserted into the upper margin of the neck of 476 OF THE LIGAMENTS. the adjacent rib. The Ligamenta Transversaria Ex- terna pass between the points of the transverse pro- cesses and the back of the necks of the ribs. The Ligamenta Cervicum Costarum Externa arise from the margin of each of the inferior oblique pro- cesses, and pass downwards and outwards to the up- per and outer part of the necks of the ribs. At its anterior extremity there is a cavity in the rib into which the sternal cartilage fits and is there unit- ed. This junction is strengthened by short ligamen- tous fibres surrounding the part and going from the rib to the cartilage. The cartilages of the seven true ribs run into pits in the sternum, and are there secured by the radiat- ed ligaments which lie in front of the joint. The Sternum is covered, both in front and behind, by a strong ligamentous expansion adhering very closely to it. From the second bone of the sternum and from the inferior margins of the seventh true ribs, near it, ligamentous fasciculi are sent to the cartilago ensiform is. PELVIS. 477 Section III. OF THE LIGAMENTS OF THE PELVIS. At the posterior part of the junction of the ilium with the sacrum, several distinct ligaments are found. The Ileo Lumbar Ligament is stretched from the transverse process of the last vertebra of the loins to the posterior superior spinous process of the ilium and the adjoining part of the crista. It is much mix- ed with fat. Just below this is the Ligamentum Sa- cro-Spinosum, which is extended between the poste- rior superior spinous process and the two or three uppermost transverse processes of the sacrum. The Sacro Iliac Ligament is an assemblage of very short strong compact fibres which lie on the back of this articulation. It is connected to the sacrum by its transverse processes and by the rough surface just on the iliac side of them, and to the ilium by the rough edge just behind its articular surface with the sacrum. In front also this articulation is covered by short strong fibres. The Os Coccygis is united to the sacrum by inter- 478 OF THE LIGAMENTS. vertebral substance and also by longitudinal ligaments on its front and back. The anterior ligament is not very distinct, but the posterior is, as it arises from the inferior margin of the spinal canal of the sacrum, and, contributing to finish the canal or to close it up, is then distributed on the back of the os coccygis to its extremity. The foramina, on the posterior part of the sacrum, are much diminished by ligamentous fibres which pass in every direction. The Posterior Sacro Sciatic Ligament arises from the inferior posterior spinous process of the ilium, from the side of the sacrum which is below it, and r ' from the side of the os coccygis. Its fibres converg- ing, it becomes thicker in the middle, and is inserted into the ridge at the inner margin of the tuberosity of the ischium, and is prolonged towards the pubis by a continued attachment along the inner margin of the ramus of the ischium. The Anterior Sacro Sciatic Ligament has its ori- gin somewhat confounded with that of the posterior. It arises from the side of the sacrum, below its junc- tion with the ilium, and from the upper part of the side of the os coccygis. Its course is more horizon- tal than that of the posterior, and it is inserted into the spinous process of the ischium. PELVIS. 479 The articular surfaces of the sacrum and ilium are covered, each with its appropriate cartilage; that on the sacrum is somewhat thicker than the one on the ilium. The contiguous surfaces of these cartilages are rough, and are separated by a yellow half-fluid te- nacious substance. The Obturator Ligament closes the obturator fora- men, arising from its margin; it is defective at the su- perior part when the obturator vessels go out. It is also frequently defective, or extremely thin below. The obturator muscles arise from it. The Ossa Pubis are joined together by a ligamento- cartilaginous matter which fills up the space between them. It is more fibrous externally, and is there form- ed of concentric lamellae which surround the articu- lation. In men there is more of this fibrous matter than in women; in the latter, one frequently finds in the posterior part of the symphysis, a little flat oblong cavity occasioned by a distinct plate of cartilage on each bone. This cavity is moistened by a white or yellowish fluid. The Sub-Pubic Ligament is a strong tendinous membrane of half an inch in breadth, occupying the very top of the arch of the pubis, and passing from one bone to the other; it is spoken of in the account of the fasciae of the pelvis. 480 OF THE LIGAMENTS. In front of this joint there are several other fasci culi of fibres, which get collectively the name of the Anterior Pubic Ligament. Section IV. OF THE LIGAMENTS OF THE UPPER EXTREMITIES. The Clavicle and the Sternum are very firmly united from the breadth of their articulating surfaces, and by the thickness of their ligaments. The Radi- ated Ligament arises from the front of the internal end of the clavicle, and is inserted around the mar- gin of the corresponding part of the articular surface of the sternum. The Interclavicular Ligament lies on the posterior surface of the upper end of the ster- num, and passes from one clavicle to the other. The Capsular Ligament proceeds from around the internal end of the clavicle, and is inserted into the margin of the articular surface of the sternum. By cutting it open we find that there is a moveable carti- lage interposed between the two bones, connected by its margin with the internal surface of the capsular ligament, and that on each side of this cartilage there is a distinct synovial membrane. The Costo-Clavicular or Rhomboid Ligament UPPER EXTREMITIES. 48I arises from the cartilage of the first rib, and is insert- ed into the tubercle on the under surface of the clavi- cle, near the sternum. The Scapulo-Clavicular Ligaments are two in num- ber. The first is a capsular ligament with its syno- vial membrane, which unites the acromial end of the clavicle to the acromion process. This ligament be- ing thickened above and below, these parts are called the Superior and the Inferior ligaments; occasionally a moveable cartilage is found also in this joint. The second ligament is the Conoidal; its apex arises from the tubercle at the root of the coracoid process, and its base is inserted into the tubercle near the acromial end of the clavicle. From the sternal margin of the conoid, a ligamentous membrane is extended in front of the subclavius muscle, called the Trapezoid Ligamant. The Triangular Ligament of the Scapula is ex- tended over the shoulder joint. Its basis arises from the acromial margin of the coracoid process, and its apex is fixed to the back part of the sternal margin of the acromion. It is thinner in the middle than at either edge. The Posterior Ligament of the Scapula is stretched across the semilunar notch, and converts it into a foramen for the vessels. Sp 482 OF THE LIGAMENTS. OF THE SHOULDER JOINT. The Scapulo-Humeral Articulation is formed by the glenoid cavity of the scapula, and the head of the os humeri. A capsular ligament arises from the neck of the former, and is inserted into the neck of the latter. A fold or thickening of it called the Acces- sory Ligament, passes from the coracoid process to- wards the great tuberosity of the os humeri. By cutting open the joint we see the synovial mem- brane lining its cavity, and sending a process into the groove of the os humeri, which is afterwards reflect- ed along the tendon of the biceps in such a way as to keep its cavity entire. This tendon is connected with the upper margin of the glenoid cavity, and sends on each side a fibrous pad which surrounds the mar- gin of the cavity, and deepens it. OF THE ELBOW JOINT. The Elbow Joint has a capsular ligament arising from the margin of the articular surface of the os hu- meri, and inserted into the margin of the articular surface of the ulna, and into the coronary ligament of the radius. This capsule has additional fibres in- ternally and externally, called Lateral Ligaments, or Brachio-Ulnar, and Brachio-Radial The first arises from the internal condyle, and spreads in a radiated UPPER EXTREMITIES. 483 manner to be inserted into the inner side of the coronoid process. The second arises from the exter- nal condyle, and is inserted into the coronary ligament of the radius. The Coronary Ligament of the Radius arises from one side of the sigmoid cavity of the coronoid pro- cess of the ulna, and surrounding the neck of the radius it is inserted into the other side of the same cavity. Its upper margin is blended with the capsu- lar ligament, and its lower is loosely attached to the root of the neck of the radius. On the anterior and posterior surfaces of the cap- sule of the elbow joint, there are small and irregular fibres, termed accessory ligaments, but the capsule is particularly thin under them, in order to accommo- date the flexions of the joint. By cutting open the capsule we see the extent of the synovial membrane, and the cartilaginous surfaces of the bones. At the bottom of the greater sigmoid cavity of the ulna, a small quantity of vascular adi- pose matter is found. The Interosseous Ligament fills up the space be- tween the radius and the ulna, being fixed on each side to their sharp edges. It is composed principally of oblique fibres interwoven with each other, and in 484 OF THE LIGAMENTS. it are several perforations for blood-vessels. One particularly large is just at the tubercle of the ra- dius. OF THE wrist joint. The Wrist Joint is formed between the lower ends of the radius and ulna, and the three first bones of the upper row of the carpus. A capsular ligament passes from the margin of the cartilaginous surface of the radius, and from the part of the same cartilage which is continued between the ulna and the cuneiform bone, and is inserted into the margin of the articular head formed by the scaphoid, lunar, and cuneiform bones. The External Lateral Ligament arises from the styloid process of the radius, and is inserted into the scaphoid bone. The Internal Lateral Ligament arises from the styloid process of the ulna, and is inserted into the inner side of the cuneiform bone, and the corresponding part of the anterior ligament, which confines the flexor tendons. By cutting open this articulation we see the syno- vial membrane of the part, and a fold of it called the Mucous Ligament, which passes from between the scaphoides and lunare to the end of the radius. We also see the cartilage of the radius projecting be- UPPER EXTREMITIES. 485 fween the cuneiform bone and the head of the ulna, and forming a distinct joint with the head of the ulna, surrounded by a capsule called the Sacciform Liga- ment. The Articulation between the first and the second row of carpal bones is performed by a capsular liga- ment which goes from the first to the second row, be- ing strengthened laterally by a multiplication of its fibres, constituting lateral ligaments internally and ex- ternally. There are also several fasciculi of fibres which run in varied directions, some oblique and some transverse, fastening the two rows together as well as the individual bones of the same row. When this joint is opened we find but one synovial membrane for the two rows of bones where they are in contact, and this membrane sends in digital processes between the lateral surfaces of the several bones which are opposite to each other. There are strong ligaments which go from the car- pal to the bases of the metacarpal bones, but owing to the irregular surfaces of these bones but little mo- tion is allowed, although the apparatus of articulation is complete with its capsular ligaments and synovial membranes. The metacarpal bone of the little finger has more motion than those of the other fingers; the ring-finger is next; the middle and fore-fingers are almost stationary 486 OF THE LIGAMENTS. The Metacarpal Bones of the fingers are connect- ed to each other at their bases by transverse ligamen- tous fasciculi; they are also connected at their heads in the same manner. A strong capsular ligament, with its synovial mem- brane, is applied to the articulation between the tra- pezium and the thumb. This capsule is of nearly an uniform thickness, being very similar, in that respect, to the capsule of the shoulder joint, and, therefore, ad- mits of every variety of motion. Between the heads of the metacarpal bones and the first phalanges there is a capsule and a synovial membrane. The capsule is thickened at its sides by which lateral ligaments are formed. In front it has a cartilaginous thickening which forms a trochlea for the flexor tendon. Behind it is thin, its principal strength being derived from the tendon of the exten- sor muscle. The Phalanges are articulated in the same way with each other that they are articulated with the me- tacarpal bones. INFERIOR EXTREMITIES. Section V. LIGAMENTS OF THE INFERIOR EXTREMITIES. The Hip Joint is formed by the acetabulum and the head and neck of the os femoris, which parts are enclosed in a strong capsular ligament arising on the outer circumference of the margin of the acetabulum, and inserted into the root of the neck of the os femo- ris. The capsular ligament varies in its thickness at different places; in front it is a fourth of an inch thick, internally it is somewhat thinner, and posteri- orly where it is covered by the quadratus muscle it is thinnest. The surface of the ligament which looks towards the cavity of the joint, is reflected some- what at its junction with the neck towards the head of the os femoris, and forms regions or retinacula. From the anterior inferior spinous process, a number of accessory filaments arise, giving to. the capsule an increased thickness above. By cutting open the capsule we see that its inter- nal face as well as the surfaces of the bones are covered by a delicate synovial membrane; that a strong ligamentous cord passes from one side of the notch in the lower part of the acetabulum to the other. 488 OF THE LIGAMENTS. leaving an opening below for the introduction of ves- sels into the cavity of the articulation. The Ligamentum Teres arises from the pit in the head of the os femoris, and seems to be inserted into the bottom of the acetabulum, but by dissecting the synovial membrane from it, its insertion into the infe- rior margin of the cord, subtending the notch, will be established. The depth of the acetabulum is increased by a ligamentous margin which surrounds it, and is within the origin of the capsular ligament. A quantity of loose vascular adipose matter fills up the pit in the bottom of the acetabulum, and is covered by the synovial membrane. By some anatomists it is called the Gland of the Hip Joint. OF THE KNEE JOINT. The Knee Joint is formed by the os femoris, tibia, and patella. It is surrounded by a capsular ligament which is very thin and loose on each side of the ten- don of the patella, and which is placed in contact with the fascia of the lower extremity as the latter is continued over the knee. The External Lateral Ligament arises from the tu- bercle of the external condyle, and is inserted into- the INFERIOR EXTREMITIES. 489 head of the fibula. The internal lateral ligament arises from the tubercle of the internal condyle, and is in- serted into the inner side of the head of the tibia, being continued for some distance down the internal side of the bone. The front of the joint is much strenghthened by the ligament which passes from the point of the patella to the tubercle of the tibia. On the posterior face of the capsular ligament is found an irregular collection of fibres passing obliquely from the upper back part of the external condyle, to be inserted into the back of the head of the tibia; these constitute the Ligament of Winslow. By opening the joint in front, so as to let the pa- tella fall upon the tibia, a good view of its internal arrangement may be obtained. The synovial mem- brane will be seen arising from the cartilaginous mar- gin of the head of the tibia and around that of the patella; but it is reflected on the os femoris half an inch or more above the margin of its cartilaginous surface, at the front and sides of the condyles, there- by supplying the place of periosteum. On both sides of the ligament of the patella, and between it and the synovial membrane, a large mass of fat is found filling up the vacuity between the condyles and the head of the tibia. This fat projects into the cavity of the articulation, and forms on each side of the pa- tella an oblong ridge covered by the synovial mem- brane, which is called, on the outside of the patella, 3q 490 OF THE LIGAMENTS the Ligamentum Alare Majus, and on its inside, the Ligamentum Alare Minus. These ligaments terminate each in a point below the patella where they are in contact with each other, and from this place a du- plicature of synovial membrane is extended to the posterior part of the articulation, terminating on the crucial ligaments and on the os femoris between its condyles. This duplicature is the Ligamentum Mu- cosum. At the posterior part of the joint, are fixed the Crucial ligaments, two in number, the Anterior and the Posterior. The first arises from the internal face of the external condyle, and is inserted in front of the ridge on the top of the tibia, its fibres being blended with those of the semilunar cartilages. The Posterior arises from the external face of the inter- nal condyle of the os femoris, and is inserted into the head of the tibia behind the ridge on its top, some of its fibres being blended with the external semilunar cartilages. These ligaments are exterior to the syno- vial membrane. The Semilunar Cartilages are two in number, placed between the tibia and the os femoris; to see them well the last bone must be removed, leaving them on the tibia. These cartilages are thick at their exterior circumference and are brought to a thin edge inter- nally ; they are fastened to the capsular ligament by INFERIOR EXTREMITIES. 491 their outer margins, the internal are loose; their upper and under surfaces are covered by the synovial mem- brane. The internal is longer from before back- wards than transversely, it is therefore nearly semi- circular; the external is almost circular, in each of which cases they exactly conform to the articular surfaces of the tibia. The posterior end of both of these cartilages is fixed to the tibia behind the spine on its top, and in front of the posterior crucial liga- ment, their anterior ends are inserted into the tibia before the same spine. Occasionally a transverse ligamentous band is seen to unite their anterior ex- tremities. The height to which the synovial membrane as- cends above the patella, should be noticed by the stu- dent, as well as a large bursa just behind the tendon of the extensor muscles which occasionally communi- cates with the joint. OF THE PERONEO-TIBIAL ARTICULATION. The head of the fibula, where it is united to the tibia, has all the apparatus of a moveable joint. The capsular ligament is thickened in front and behind, which occasions the names of Anterior and Posterior Ligaments. But this joint is particularly strengthened by the insertion of the external lateral ligament of the knee and by the tendon of the biceps muscle, 492 OF THE LIGAMENTS. The Interosseous Ligament fills the interstice be tween the two bones, being attached to ridges which lie on their opposing surfaces and run the greater part of their length. It consists of oblique fibres going from one bone to the other, and forming a thin strong membrane. Just below the head of the tibia it is perforated by a large foramen which transmits the ti- bialis posticus muscle and the anterior tibial artery and vein; near the ancle joint it is perforated also by the fibular artery. Below, the tibia and fibula are approximated at the ancle joint by triangular surfaces, concave on the part of the tibia, and convex on the part of the fibula. These surfaces are held together by intermediate li- gamentous matter, as well as a ligament expanded on the front and back of the junction called the Anterior and the Posterior Ligaments. The cartilaginous crust, on the ends of the tibia and the fibula, contributing to the ancle joint, are continued for the sixth of an inch on the opposed surfaces of the tibia and the fibula. OF THE ANCLE JOINT. The Ancle Joint is formed by the tibia, fibula, and astragalus. The capsular ligament is extremely thin, and, indeed, has no very evident existence before and behind, the fatty matter which surrounds the joint ap- pearing to be in immediate contact with the synovial INFERIOR EXTREMITIES. 493 membrane, and to protrude it, in some places, inwards towards the cavity of the articulation. There are very strong lateral ligaments on both sides. The Deltoid arises from the inferior extremity of the malleolar process of the tibia, and is inserted, by radiating considerably, into the internal side of the os calcis, astragalus, and scaphoides. The ligaments on the external side of the ancle are divisible into three fasciculi. The Anterior arises from the ante- rior part of the end of the malleolus externus, and passes obliquely forwards to be inserted into the up- per and outer part of the astragalus. The Middle Ligament or Fasciculus arises from the extremity of the fibula, and descends perpendicularly to be insert- ed into the outside of the os calcis. The Posterior Ligament comes from the back of the extremity of the malleolus externus, and passes very obliquely to be inserted into the outer back part of the astragalus On cutting open this joint, it will be seen that the synovial membrane is connected to the several bones at the margins of the cartilaginous articular surfaces. LIGAMENTS OF THE FOOT. The os calcis and the astragalus are united by cap sular ligaments investing their articulating surfaces; the capsule belonging to their posterior surface is in- 494 OF THE LIGAMENTS. sulated, but the anterior is extended into that which unites the os astragalus and the naviculare. Between the two bones there is a very strong ligament arising from the fossa of one to be inserted into the fossa of the other; it is their strongest means of union. The Naviculare and the Astragalus are united by a capsular ligament with its synovial membrane. This capsule is thickened by additional slips above and in- ternally; the whole arrangement of the joint is such as to admit of much motion. The Os Calcis and Cuboides, besides their capsu- lar ligament and synovial membrane, have an acces- sion of fibres called Superior, Lateral, and Inferior Ligaments. i A very strong ligament passes from the anterior in- ternal part of the os calcis, and is fixed into the tuber- cle on the under surface of the scaphoides. This li- gament supports the astragalus. There are many other strong ligaments connecting the bones of the tarsus together; their course is varied and complicated. Besides which there are capsular and synovial membranes to the several opposed arti- cular surfaces of bones. The Ligaments of the Metatarsus and of the Pha- OF THE SKIN. 495 langes correspond so nearly with those of the meta- carpus and the phalanges of the fingers, that the reader is referred to the account of the Ligaments of the Hand. Of the Skint Hair, NaUs, and the Sebaceoum Organs, OF THE SKIN. The Skin consists of Cuticle, Corpus Mucosum, and the Cutis Vera. These parts are easily separat- ed from each other by maceration, and by boiling or immersion into hot water for a few minutes and im- mediately afterwards throwing the part, thus heated, into cold water. Vesicatories also, applied to the liv- ing body, cause the cuticle to detach itself from the parts below. The Cuticle is a very thin semitransparent mem- brane, for the most part distributed over the surface of the body. In some parts from birth it is much thicker than in others, as in the palms of the hands and the soles of the feet, and from friction and pressure in after life, it increases further in its proportionate thick- ness. The cuticle presents every where, but more obviously in the hands and feet, a multitude of fur- rows depending on the surface of the cutis vera, which are arranged in straight, curved, or spiral lines. It 496 OF THE SKIN. adheres by filaments to the cutis vera, and is perforat- ed by the exhalent or perspiring vessels, by the ex- cretory ducts of the sebaceous glands, by the hairs, and according to some anatomists by the origin of ab- sorbent vessels. These perforations are best seen on the nose, ears, external parts of generation, the palms of the hands, and the soles of the feet. From the inter- nal surfaoe of the cuticle processes are sent in, which line the different foramina of the cutis vera. When the cuticle is raised by a blister these processes be- come collapsed, by which their sides are approximat- ed, and the fluid effused beneath is prevented from escaping. The cuticle has but little elasticity, no vascularity, and no sensibility. Its use seems to be to diminish evaporation from the surface of the body, and to shield the pulpy terminations of the nerves of the cutis vera. The Corpus or Rete Mucosum is the second layer of the skin, and on it depends the great variety of co- lours observed in the human species. It covers every part of the cutis vera except under the nails. Its consistence is mucilaginous, from which its name is derived. Mr. Gaultier gives the following account of it in Marjolin's Anatomy, vol. ii. p. 587. On the soles of the feet in negroes the corpus mucosum is seen to be disposed in the following manner: 1st. On the in- OF THE SKIN. 497 equalities of the cutis vera bloody pimples, (Bour- geons Sanguins,) are placed. 2d. Next to them is a layer which he calls Albida Profunda, on account of its constant colour and situation. 3d. Small points, constituting a layer placed over the last, of a very dark brown in negroes, which he calls Gemmula. And 4th, a layer next to the cuticle spread over the last, called Albida Superficialis. In cutting through the skin, from the heel to the toes, at right angles to its furrows, in negroes, this arrangement may be readily recognized. And in cases where it has been rendered indistinct from sick- ness it may be improved by immersing the skin for three or four days in lime water, a solution of potash or bar} tes, and afterw ards keeping it the same length of time in a solution of corrosive sublimate. The existence of this arrangement of the corpus. mucosum may be established in other parts of the body by the effects of blisters. The fluids being thus locally attracted, infiltrate the corpus mucosum and separate its layers, in part, in order to form a vesicle, frequently very thick, particularly in fat persons. The Cutis Vera gives a covering to the whole body. It consists of fibres variously blended and running in every direction. Its blood-vessels and nerves are so numerous that the prick of the finest needle in any 3r 498 OF THE HAIR. part will occasion pain and produce blood. Its inte- rior surface is in close connection with the subjacent cellular and adipose membrane, from which it may be separated by dissection. The cutis vera is extremely elastic. Its thickness varies; on the back, on the soles of the feet, and on the palms of the hands it is thicker than elsewhere. On the lips and on the margin of the anus it is very thin. The cutis vera, on its external face, is divided by numerous lines running in different directions. When the cuticle is removed, this surface is seen to be stud- ded with papillae which are extremely sensitive and vascular. They are very obvious on the palms of the hands and on the soles of the feet, where they are ar- ranged in double rows on the ridges of the cutis vera. OF THE hair. The Hair grows in the cellular membrane beneath the skin. It is best studied on the mustachios of the larger animals, as the horse, ox, and so on. Around the root of each hair there are two capsules, one within the other. The internal is very vascular, antl the blood reaches it, not from the bottom, but near the surface of the cutis. In the root of the hair'there is a hollow canal filled with a pulpy substance. OF THE SEBACEOUS ORGANS. 499 OF THE NAILS. The Nails are fibrous, and derived from the cuticle. If they are torn off by pincers or separated by mace- ration, their form and origin may be readily seen. OF THE SEBACEOUS ORGANS. These consist of follicles and glands. The follicles are placed around the roots of the hair in the interior of the capsules. They secrete an unctuous fluid which, by inspissation, becomes of the consistence of suet. Being seated under the skin they are more abundant in some parts than in others, as, for exam- ple, in the nose, ears, groins, and external parts of generation. The Sebaceous Glands are about the size of millet seeds, and are placed also under the cutis vera. They are particularly numerous under the skin of the mons veneris. INDEX. Page Axillary Plexus, .... 49^ Artery, .... 385 Vein,.....399 Arbor "Vitae, ...... 64 Accessory Nerve, .... 104 Gall. Auditory Nerve,.....107 Gall. Adductor Oculi,.....115 Aqueducts'of Ear, . . . . 139 Azygos Uvulae, ......150 Aorta,.....179,325, 327 Abdomen,......., 191 regions of, ... 191 muscles of, . . . 192 contents of, . . . 221 Abdominal Kings, .... 205 Canal, .... 206 Appendicular Epiploicae, . . 228 Aponeurosis Pelvica, . . . 289 Areola,........313 Anconoeus,.......364 Anastomotica,......390 Arcus Profundus,.....392 Sublimis,.....397 Adductor Muscles of Thigh, . 419 Articular Arteries of Knee, . 450 Anterior Tibial Artery, . . 454 Auricle, Right,.....173 Left,......177 Back, Muscles of,.....340 Buccinator, ...... 8 Brain,.......51, 77 arteries of, . ... 75 basis of, .....62 Bronchia,.......183 Bronchial Arteries, . . 185, 326 Bladder, ....... 263 Biceps Flexor Cubiti, . . . 360 Cruris, ... 425 Brachialis Internus, .... 362 Brachial Artery,.....385 Basilic vein,......398 Ciliaris, ........ 5 Corrugator Supercilii, ... ib. Compressor Naris, .... 3 Page Carotid Artery,.....29 Cervical Nerves,.....49 Cerebrum,......55,87 Centrum Ovale,.....57 Corpus Striatum...... . 58 Commissura Mollis, .... 60 Anterior, ... 62 Posterior, ... ib. Commissures of Cerebellum, . 85 Gall. of Cerebrum, . 90 Gall. Cerebelluwf, ..... 62, 82 Gall. Crura Cerebri,.....64 Cerebelli,.....ib. Corpora Albicantia, .... 66 Cauda Equina,.....75 Convolutions of Brain, ... 97 Gall. Cornea,........121 Choroides Tunica, .... 122 Ciliary Ligament, . . . . 123 Cochlea,........137 Constrictor Isthmi Faucium, . 150 Constrictors of Pharynx, . . 152 Cremaster,.......201 Corpus Cavei-nosum, . . . 271 Spongiosum, . . . 272 Couper's Glands,.....275 Coccvgeus.......286 Clitoris,........298 Carunculae Myrtiformes, . . 304 Cardiac Plexus,.....319 Creliac Artery,.....327 Cervicalis Descendens, . . . 348 Complexus, ......349 Coraco Brachialis, .... 361 Circumflex Arteries, . . . 388 Cephalic Vein,.....397 Cutaneus Internus, .... 402 Corpus Callosum, . . , . 57 Cruraeus,.......416 Cutaneous Nerves of Thigh, . 460 Cruralis Anterior, .... 462 Cuticle,........493 Cutis vera,.......497 Cervicalis Ant. Arteria, . . 36 Post. Arteria, . . ib. 502 INDEX. of, External Carotid, Eighth pair of Nerves, Eye,...... Humours of, . . Vessels and Nerves Ear,...... Muscles of, . . Bones of, . . . Nerves of, . . Eustachian Tube, Epididymis, . . . Emulgent Arteries, . External Iliac Artery, Epigastric Artery, Extensors of Fore-arm, of Thumb, Extensor Long. Digit. Pedis, Pollicis Pedis, External Circumflex Artery, Plantar, . . . is, Depressor Labii Sup. -Masque Nasi,..... Anguli Oris, Labii Inferior Oculi, . . Digastricus, . . . Diaphragm, . . . Ductus Ejaculatorius, Dorsalis Sup. Scapulae, DeltoMes, .... Dura Mater, . . . 6 7 ib. 115 17 255 269 386 357 52 30 70 112 125 127 129 132 134 140 143 280 329 334 335 374 375 427 4V8 447 456 Fascia Superficialis of Neck, . 10 Profunda of do, . . 13 Facial Artery,......31 Fifth pair of Nerves, ... 39 Fossa Sylvii,......56 Fornix,........58 Foramen of Monro, .... 60 Facial Nerve, ....... 107 Fauces,........149 Fascia Transversalis, . . . 206 Superficialis Abdominis, 213 Femoris, .... 213,410 Iliaca.......215 Falciform process of Perito- neum, .......207 Femoral Hernia,.....211 Sheath,.....218 Foramen of Winslow, . . . 228 Female Pelvis,.....296 Fallopian Tubes,.....308 Flexors of wrist,.....365 of fingers, .... 367 of thumb, .... 369 of toes,.....43? Page Foot, Muscles of,.....435 F.-iscia of, ..... 436 Femoral Artery, ..... 445 Fore-arm, Muscles of, . . . 364 Genio Hyo-Glossus, .... 19 Hyoideus,.....ib. Glosso Pharyngeal Nerve, 43, 106 Gall. Glandulae Labiales et Buccales, 148 Glisson's Capsule, .... 242 Gall-bladder,......243 Gracilis,........418 Gluteal Muscles, ..... 420 Gastrocnemius,.....430 Glottis,........161 Gemini,........423 Head and Neck,..... 1 Hyo-Glossus,......19 Hypoglossal Nerve, .... 105 Gall. Hey's Ligament,.....215 Hepatic Duct,......244 Hymen, ........ 301 Hepatic Artery,.....328 Hypogastric Artery, .... 331 Hand, Muscles of, .... 377 Hair,.........498 Heart,........171 Internal Carotid,.....35 Inferior Maxillary Nerve, . . 41 Infundibulum,......66 Iris,.........122 Intercostal Muscles, .... 166 Arteries, .... 326 Inguinal Hernia,.....203 Internal Mammary Artery, . 325 Ilir.c Arteries,......331 Interspinals,......352 Intertransversarii, .... 353 Infraspinatus,......358 Indicator,.......376 Intercosto-Humeral Nerves, . 407 Iliacus Internus,.....412 Internal Plantar Artery, . . 454 Intestinal canal,.....232 Jugularis Interna, .... 37 Externa, .... ib. Kidneys, .......250 Levator Labii Sup. Alzequi Nasi, 5 Anguli Oris, .... 6 Labii Inferioris, ... 7 Scapulae, .... 344 INDEX. 503 Page Lingualis Muscle, .... 19 Longus Colli, ......20 Lingual Artery,..... 31 Lateral Nasal Nerve, ... 41 Lateral Ventricles of Brain, . 58 Ligamentum Denticulatum, . 73 Patellae, ... 471 Lachrymal Passages, ... 113 Gland, . . . *. 114 Levator Palpebrae, .... 114 Oculi,.....115 Palati,.....151 Ani, .... 293 Labyrinth, ......136 Larynx, .......154 Muscles of ... . 159 Levatores Costarum, . . 167, 353 Lungs,........181 Large Intestines, .... 235 Liver,........238 Blood-vessels of, . . . 241 Labia Externa,.....297 Tnterna,.....299 Lumbar Arteries, .... 330 Latissimus Dorsi, .... 342 Longissimus Dorsi, .... 346 Lower Extremities, . . . 409 Blood-vessels of, 445 Veins of, . . 457 Nerves of, . 459 Lumbar Plexus,.....459 Ligaments of Head, .... 471 Spine, .... 472 Thorax, . » . . 475 Pelvis, .... 477 Upper Extremities, 480 Lower Extremities, 487 ... 9 ... 18 34 '. ' 65, 80 Gall. . 68, 110 Gall. . 69, 106 Gall. . 72,78 Gall. Meatus Auditorius Externus, . 131 Mouth,........146 Morgagni, Ventricles of, . . 161 Mediastina,.......169 Mesentery,.......229 Mesocolpn, ....... ib. Mons Veneris, .....297 Masseter, .... Mylo Hyoideus, . . Maxillaris Interna Art. Medulla Oblongata, Motores Oculorum, Externi, Medulla Spinalis, Mammae,..... Mesenterica, Superior, . Inferior, . Middle Sacral Artery, . Multifidus Spinae, . • Mammariae Externae, Median Vein, .... Musculo-Cutaneus Nerve, Spiralis Nerve, Median Nerve, . . . Meibomius, Glands of, . Page 310 328 330 ib. 350 387 398 403 ib. 405 113 Ninth Pair of Nerves, 44, 71, 105 Gall. Nose, ........142 . 144 . 499 Nerves of Nails, Occipito Frontalis, . . Orbicularis Palpebrarum, Oris, . . . Omo Hyoideus, . . . Occipital Artery, . . Olfactory Nerves, . . Optic Nerve, . . . Obliquus Sup. Oculi, Inferior Oculi, Os Hyoides, .... Obliquus Externus Abdom Internus Abdom. Omentum, .... Orrficium Urethrae, . QSsophagus, . . . Oesophageal Arteries, Obliquus Capitis Sup. Inferior, OBturator Internus, . Externus, , Obturator Nerve, Ovaries,..... Platysma Myoides, .... 11 Pterygoideus Externus, . . 22 Internus, . . 23 Parotid Gland,.....25 Pharyngeal Artery Inf. . . 32 Portio Dura,......39 Palatine Nerve,.....41 Par Vagum, .... 45, 316 Pia Mater, ".......55 Plexus Choroides, .... 60 Pineal Gland,.....61, 95 Gall. Pons Varolii,.....64, 8^ Gall. 8 . 16 . 32 67, 111 Gall. ib. 115 . 116 , 154 194 . 197 , 226 . 300 , 153 . 326 352 ib. 423 424r , 463 . 309 504 INDEX. Pnge . 66, 95 Gall. 70, 107 Gall. Par Vagum,......105 Gall. Pituitary Gland, Portio Mollis and Dura, Papillae of Tongue, . Palato Pharyngeus, . Pharynx, .... Pectoralis Major, Minor, . . Pleura,..... Pericardium, . . . Pulmonary Artery, . Posterior Mediastinum, Pyramidalis, . . . Peritoneum, . . . Pancreas, .... Pelvis, Male, . . . Viscera of, Prostate Gland, . . Penis,..... Perineum of Male, . Muscles of, Perineal Fasciae, . . Pubic Ligaments, Papilla of Female Mamma Phrenic Nerve, . . Arteries, Pronator Teres, . . Quadratus, Palmaris Longus, Psoas Magnus, . . Parvus, . . . Pectinalis, .... Pyriformis, . . . Peroneus Tertius, . Longus, . Brevis, Plantaris, .... Popliteus, .... Profunda Femoris, . Popliteal Artery, Posterior Tibial Artery Peroneal Artery, Pudendalis Sup. Nerve Peroneal Nerve, Popliteal Nerve, Pterygoid Nerve, Quadratus Lumborum, Femoris, . 149 . 150 . 151 . 164 . 165 . 169 . 170 . 177 . 189 . 199 . 224 . 248 . 261 . 262 . 267 . 270 . 282 . 283 . 283 203,288 . 313 48, 315 . 327 . 365 . 370 . 366 . 412 . 413 . 418 . 422 . 427 . 429 . 430 . 432 . ib. . 447 . 450 . 454 . 454 . 465 . 467 . 469 40 . 354 . 424 Rectus Capitis Posticus Major Minor Abdominis, Femoris, . Retina, .... Renal Capsules, . Rhomboideus, Radial Artery, Rete Mucosum, . Rectus Capitis Internus Major, 20 Minor, ib. Lateralis, . . 21 Sterno-Cleido Mastoideus, Stylo Maxillary Ligament, Hyoid do., . Sterno Hyoideus, Thyroideus, Stylo Hyoideus, . Glossus, Pharyngeus, Scalenus Anticus, Medius, Posticus, Submaxillary Gland, Sublingual Gland, Stylo Mastoid Artery, Superior Maxillary Nerve, Sympathetic Nerve, Sinuses of Dura Mater, Schneiderian Membrane, Semicircular Canals, Subclavius, .... Serratus Major Anticus, Superior Mediastinum, Stomach, .... Small Intestines, Spleen,..... Seminal Vesicles, Scrotum, .... Spermatic Cord, . . Sphincter Vaginae, . Solar Plexus, . . . Splenic Artery, . . Spermatic Arteries, Serratus Posticus Sup. Inferior, Sacro Lumbalis, . Splenius, . . . Semi-spinalis Colli, Dorsi, Supinator Longus, Brevis, . Scapular Artery, . Spiral Artery, . . Scapular Nerve, . Sartorius, . . . Semitenciinosus, . Semimembranosus, r»g« 351 352 199 415 124 254 343 391 487 INDEX. 505 Page Soleus,........431 Saphena vein,......457 Spermaticus Externus, . . . 460 Sciatic Plexus,.....463 Nerve,......466 Skin,.........492 Septum Lucidum, ... 59, 93 Gall. Spinalis Dorsi,.....347 Supra Spinatus,.....358 Subscapulars, .....359 Shoulder and arm, Muscles of, 356 Sebaceous organs, .... 490 Temporalis Muscle, .... 9 Artery, .... 33 Thyroid Gland,.....23 Arteries, ... 30,36 Veins,.....38 Tunica Arachnoidea, ... 54 Thalamus Nervi Opt. . . 58, 89 Gall. Third Ventricle,.....61 Tubercula Quadrigemina, . 61, 95 Gall. Trochleares Nerves, . . 68, 110 Gall. Trigemini Nerves, . . . 69, 109 Gall. Tunica Jacobi, .....124 Tympanum,......133 Muscles of, . . 135 Tongue,........146 Tonsil Gland,......149 Tensor Palati,......150 Thorax,........164 Triangularis Sterni, .... 167 Trachea,...... . 184 Thymus Gland,.....187 Tunica Vaginalis Communis, 204 Transversalis Abdominis, . . 198 Testicles,.......276 Tunica Vaginalis Testis, . . 278 Albuginea, .... ib. Page Tubuli Seminiferi, .... 279 Triangular Ligament of Ure- thra......286, 294 Thoracic Duct,.....338 Trapezius,.......341 Transversalis Cervicis, . . . 349 Trachelo Mastoideus, ... ib. Teres Minor,......358 Major,......359 Tensor Vaginae Femoris, . . 414 Tibialis Anticus,.....427 Posticus,.....435 Triceps Extensor Cubiti, . . 362 Thoracici Nervi,.....401 Ureter,........253 Urethra,........273 Membranous part of, 274 Uterus,........305 Upper Extremity, . . . . 355 Vessels of, . 385 Veins of, . 397 Nerves of, . 400 Ulnar Artery,......393 Nerve,......406 Valve of Brain,.....62 Vestibule of Ear, .... 137 Velum Palati,......149 Ventricle, Right,.....173 Left,.....177 Vas Deferens,......281 Vagina,........301 Veins of Trunk,.....335 Vena Cava Descendens, . . ib. Ascendens, . . . 336 Portarum, . . . 241 Vaginal Ligaments, .... 370 Vastus Externus,.....415 Internus,.....416 Vertebral Artery, .... 36 Zygomaticus Major, .... 6 Minor, ... ib. THE END. 3 8 s, %," ■# * ERRATA. Page xiii, line 8, for nor read or. xvi, 22, for Course read Coarse. xvii, 2, for Course read Coarse. 3, 20, for os read ossa. 15, 17, for glands read gland. 19, 3, for I read It. 30, 11, for continued read contained. 60, 24, for ventricles read ventricle. 28, after that read it. 69, 3, for Trigemina read Trigemini. 70, 12, for cerebri r£id cerebelli. 92, 16, for Commissura read commissure. 96, 25, for Extremity read Extremities. 98, 1, for dephths read depths. 159, 6, for cartilages read cartilage. 161, 24, for glottides read glottidis. 176, 28, for form read forms. 194, 25, for Uieum read ilium. 269, Note, for Universal read Animal. 312, line 19, for they read the. 356, Section II. for Upper Extremity read Shoulder and Arm. 443, line 22, for Interosseous read Interosseus >-; IRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICIN Un- RARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINI uvaen ivnouvn 3Ni3iQ3w jo uvubii ivnouvn 3Ni3ia3w jo *<»nii ivnouvi : >> L^l)£>. 1 X-'P '^\4^>\m\4f ° \V& N sU<& BRARY OF MEDICINE NATIONAL LIBRARY OF MEDICINE NATIONAL LIBRARY OF MEDICI VBfllT IVNOUVN 3NI3I03W JO ABVB9 ,, „.,!!.• I«»«" '° »»»•«" "N°" 1 „IBRARY OF MEDICINE N A T I O N A L L I B R A R - / J5S&m\\ z. 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