LESSONS IN PRACTICAL ANATOMY, for the w&im ®s* n»is©ia©©(DiBP« By W. E. HORNER, M. D., PROFESSOR OF ANATOMY IN THE UNIVERSITY OF PENNSYLVANIA J SURGEON AT THE PHILADELPHIA HOSPITAL, Blockhy, &C. THIRD AND x.viPROVED EDITION. PHILADELPHIA: PUBLISHED BY J. G. AUNER, NO. 331 MARKET STREET. 1836, •i f«.i>n. aj$. Sz^l mc-Zf Entered, according to the Act of Congress, in the year 1823, by William E. Horner, M.D., in the Clerk's Office of the District Court of the United States for the Eastern District of Pennsylvania. Printed by T. K. &. P. G. Collins, No. 1 Lodge Alley TO PHILIP S. PHYSICK, M. I)., 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 en- couragement, 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 }^our notice; however, as it is the best at present in my power, I hope that it will be accepted in the sense in which it is offered. That a life so usefully employed as yours in mitigating 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 1st, 1823. CONTENTS. Page Preface,.......- - vii Introduction.—On Dissecting, and on the method of making Anatomical Preparations,......xiii 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, - 50 Sect. I. Of the Brain and Spinal Marrow, - - 50 II. Of the Brain and Spinal Marrow, according to Gall and Spurzheim, 76 III. Of the Eye,......110 IV. Of the Ear,......126 V. Of the Nose,......139 VI. Of the Mouth,.....143 VII. Of the Pharynx and (Esophagus, - - 148 VIII. Of the Larynx,.....152 PART II. Of the Trunk,........159 Chap. I. Of the Thorax,......159 Sect. I. Of the Muscles in front, and on the sides of the Thorax, - - - - - - 159 II. Of the Viscera of the Thorax, - - - 162 Chap. II. Of the Abdomen, - - - * - - - 186 Sect. I. Of the Muscles of the Abdomen, - - 187 II. Of the Parts concerned in Inguinal Hernia, 198 III. Of the Parts concerned in Femoral Hernia, 207 IV. Of the Contents of the Abdomen, - - 216 V. Of the Diaphragm, &c. ... 250 vi CONTENTS. Page Chap. III. Of the Male Pelvis, - 258 Sect. I. Of the Viscera of the Male Pelvis, - - 258 II. Of the Perineum and the Fasciae of the Male Pelvis,......278 Chap. IV. Of the Organs in the Female, for the Generation and Nourishment of the Infant, - 292 Sect. I. Of the Female Pelvis, .... 292 II. Of the Female Mammae, 306 Chap. V. Of the Nerves and Vessels of the Trunk, - - 311 Sect. I. Of the Nerves,.....311 II. Of the Blood vessels, .... 320 III. Of the Thoracic Duct, - - - --334 Chap. VI. Of the Muscles of the Back, .... 336 PART III. Of the Extremities, - - - - - - -351 Chap. T. Of the Upper Extremities, .... 351 Sect. I. Of the Fascia, .....351 II. III. Of the Muscles, .... 352 IV. Of the Blood vessels, - - - - 380 V. Of the Nerves,.....395 Chap. II. Of the Lower Extremities, .... 404 Sect. I. Of the Fascia, - - . - - - . 404 II. Of the Muscles,.....407 III. Of the Blood vessels, .... 437 IV. Of the Nerves,.....451 PART IV. Of the Ligaments, -.-.,.. 453 Chap. I. Ligaments of the Head and Trunk, - - - 463 Sect. I. Ligaments of Head and Spine, - - - 463 II. Ligaments of Thorax, .... 457 III. Ligaments of Pelvis, .... 459 Chap. II. Ligaments of the Upper Extremities, - - 472 III. Ligaments of the Inferior Extremities, - 480 PART V. Of the Integuments, -----.. 439 Chap. 1. Skin, -- - - - - . . ^gg II. Hair, - - -.....493 III. Nails, - ... . . .493 IV. Sebaceous Organs, - 494 Index,..........495 PREFACE TO THE THIRD EDITION. The following sheets were put together originally, with a hope of their contributing to facilitate the most diffi- cult and important part of a medical education, the study of Practical Anatomy, or of Anatomy by person- al dissections; and are the result of many observations made in the course of twenty-four years by myself, or by the young men who have confided in me by submitting to my instructions. The arrangement is in some re- spects unusual, as regards a work on this branch of science; 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 mo- derate activity of mind, who do not, in the prosecution of a study even new to them, adopt some labour-sav- ing means, overlooked and sometimes unknown, to such as are much further advanced. It has happened to me frequently, while superintending the studies of others, to observe this fact; and also that none of the books in common use answered continually for reference, either VI11 PREFACE. in consequence of their actual plan not being suitable to the course of dissections, or from the partition of the subject among several students, causing the dissection of one person to interfere with that of another. The idea of forming a text-book to obviate the latter was thus suggested; and I trust, therefore, that the present treatise will, in most cases, be found to answer either where several students dissect together on the same subject, or where the student dissects alone upon a por- tion of the body. In the original conception of the work it appeared to ma that I might introduce advantageously remarks on Morbid Anatomy, &c; but in computing the number of pages that the descriptive anatomy alone would oc- cupy, I found that such a mass of materials would be- come a system, and interfere much with the simplicity and conciseness that I wished to predominate in the character of the performance. I have therefore inten- tionally indulged very seldom in such remarks. But as their introduction is common in manuals of Ana- tomy, I will state why it has not been imitated in the present. In my own progress as a student, I had a hand-book of that kind, but it very frequently happen- ed that the subject 1 was engaged in dissecting, had none of the diseases or morbid appearances, that the page I was reading referred to. The author indeed PREFACE. ix 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 de- scriptive anatomy so much by alternate sentences for each, and sometimes in the same sentence, that the eye could not without much trouble, distinguish what was appropriate. A positive inconvenience was thus sus- tained. 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 committed a fault: my general intention has been, in all cases, to assist by directions where the novelty and obscurity of the operation left no clew for the student; but where the dissection or mode of ex- amination 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 dif- ferently 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 faculties, who B x PREFACE. 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 less occupied with it. 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 pro- bably 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 comprehend or receive at once all of them. In this dilemma 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 first. The plan of the book enables the student to commence with either of the parts, with nearly equal advantage. In adopting it, the most prominent objection to my mind was the necessity of repeating the same observations in differ- * This arrangement has been slightly altered in the present edition but not in such a way as to affect the general plan of the work. PREFACE. xi ent 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 blem- ish of much magnitude. As the objects of this book are limited to what its title page proposes, any deficiency in it must be made up by consulting my Treatise on Special and General Anatomy, 4th Ed. 1836. 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 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 freedom 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 different de- pressions about the subject, when it can be conveni- ently got out. He should keep a sponge for himself, for where a sponge is used by several it becomes nobody's business to clean it; the consequence is that xiv INTRODUCTION. it is seldom fit for use. When the integuments of a subject are laid open, the parts exposed either dry or putrefy rapidly. A constant rule is hence established not to turn down more skin than the freedom of dissec- tion requires, and to save it as much as possible to cover the parts again, when the dissection is suspended for an interval. When there is not enough of it for this purpose, a damp 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 answer. The integuments of the parts covering the muscles, should be held perfectly tense with the other hand, or with the forceps. The knife should be passed 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 student. of injections.* There are three kinds of injections in use among anatomists, the Coarse, the Fine, and the Minute; which * Swammerdam first used wax injections and that about the year 1672. Corroded preparations were first made by Francis Nicolls, INTRODUCTION. are applied to the filling of the arteries and of the veins, in order to demonstrate their course more satisfactorily. No. I. * For coarse injections, take the following ingredients: Yellow Bees-Wax, pure, sixteen ounces, Bleached Rosin, eight ounces, Turpentine Varnish, by measure, six ounces.* Or, No. II. Yellow Resin, two pounds. Yellow Wax, one do. Turpentine Varnish, a sufficient quantity to make the mix- ture flexible when cold.f Or, No. III. Tallow, two pounds, White Wax, ten ounces, Common Oil, six ounces, Venice turpentine, four ounces.J Mix and liquefy them over a slow fire, or, what is still better, in boiling water. Professor of Anatomy at Oxford, about the beginning of the last cen- tury. Rouhaut, a surgeon of the King of Sardinia, first dissolved glue to inject small vessels with. Homberg of Paris, proposed a mixture of equal parts of tin, bismuth and brass, wherewith to inject blood-vessels by means of a pneumatic apparatus for forcing it in. * Fyfe,....Pole. t Nicholls. } Munro. XVI INTRODUCTION. do. do, do. do. do. do, do. do. do. do. For making either mixture red; add Vermilion -iij. yellow; King's Yellow, gijss. white; Best Flake White, gvss. rBest Flake White, ^iijss. pale blue; | pine BJue Smalt? ^.^ dark blue; Blue Verditer, gxss. black; Lamp-Black, §i. r Powdered Verdigris, fivss. do. do. green; < Best Flake White, ^iss. L Gamboge, powdered, ^i. No. IV. For Fine injection take the following: Brown Spirit Varnish, oiv. White Spirit Varnish, ^iv. Turpentine Varnish, §i. Mix and heat. To make this mixture red; add Vermilion, gi. do. do. yellow; King's Yellow, gii. do. do. white; Best Flake White, gij. r Fine Blue Smalt, §iss. do. do. light blue; | Best Flake White,si^. do. do. dark blue; Blue Verditer, giv. do. do. black; Lamp Black, gss. Or, No. V. According to Dr. Munro, a fine injection maybe obtained, by pouring oil of turpentine on any finely powdered colouring matter, till it reaches a proper consistence. INTRODUCTION. xvii No VI. For Minute injection take the following: Most Transparent Glue, broken to pieces, or isinglass,* ^viij. Water, Ibiss. Mix. Let it stand till the glue is soft, which will take from one to two days. Then heat it gently till the consist- ence is uniform, or a perfect size is made. To make this mixture red; add Vermilion, 3 v. do. do. yellow; King's Yellow, %iv. do. do. white; Best Flake White, £v. do. do. blue; Fine Blue Smalt, gviij. r Powdered Verdigris, gi do. do. green;-< Best Flake White, ^ij. 1 Gamboge powdered, 3 do. do. black; Lamp-Black, §i. In all of these formulae for Injections, it is of the utmost importance to success in throwing them in, to 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 * The Isinglass is much more expensive, but more minute. C xvm INTRODUCTION. colours are added, through a fine flannel cloth, which will arrest the impurities both in the original mixture and in the colouring ingredients. No. VII. A commodious preparation, 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 under- stood, in other parts of the United States, and is com- monly called the Cold Injection. To make it, take White Lead and Red Lead, of each giv. Linseed Oil enough to form a thick paste by rubbing them well together. Liquefy this paste with Turpentine Varnish, gviij. Just before injecting sprinkle this mixture with cold water. The advantage of it is, that it does not re- quire the subject to be previously heated. The colour may be improved with vermilion.* These ingredients are used in various proportions * As making a mixture for each time one has to inject is rather troublesome, a larger quantity of the ingredients with the exception of the varnish may be blended, and then kept fluid for a long period by pouring water in the vessel. After the varnish is once added the mixture must be used immediately, as it then begins to thicken. This is a very common injection, and several persons have supposed them- selves to be the inventors of it. I have lately been informed by the Right Rev. Bishop Onderdonk of Pennsylvania that it originated with Mr. Allan Ramsay a Scotch Anatomist. INTRODUCTION. xix by different anatomists, and it may be found advan- tageous to increase or diminish their relative quantity according to circumstances. The Red Lead is more drying than the White, and is sometimes used without the other as follows: No. VIII. Red Lead. Linseed Oil sufficient to bring it to the consistence of putty. Then equal parts of Spirits of Turpentine and Turpentine Var- nish, until it is reduced to a semifluid state. Just before injecting sprinkle it with a little water and stir it.* White Lead, treated in the same way with linseed oil and turpentine varnish, may have its colour changed to fancy by any of the colouring matters mentioned. It is not necessary to strain these lead mixtures. No. IX. When the student wishes only to prosecute the dis- section of the vessels without making a preparation of them, the following injection will answer. Tallow, ibij. Turpentine Varnish, §x. Red Lead, Sviij. Mix. * Chailes Bell's system of Dissections, London, 1809. XX INTRODUCTION. 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 secondary arterial trunks, without heating the subject. Its cheap- ness makes it very advantageous. The success of this injection will be increased by throwing in first, a syringe full of Nos. IV. or V. pro- perly heated, with a view of warming somewhat the vessels and removing their rigidity. In the use of these formulae, excepting Nos. VII. VIII. and IX., it is indispensable to warm the subject thoroughly by previous immersion in water hot enough to excite the sensation of scalding in the finger. If the water be warmer, it will cause the parts to contract and become rigid instead of softening them. The in- jections must be of a proportionate 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 corroded and dried preparations. Nos. II. and III. for the latter alone. Nos. IV. and V. are sometimes used as the precursor to the three first. No. VI. is adopted in wet preparations and such as are INTRODUCTION. xxi intended to demonstrate minute vascularity. Nos. VII. and VIII. answer remarkably well for dried prepara- tions; 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 ve- nous, or both. It is therefore unnecessary to extend this paper by describing the method of proceeding in each individual preparation, general rules being suffi- cient, and to the intellectual mind much more accept- able. dried preparations. Whenever a section of the body, as the head, the arm, leg, or any other part, is to be injected, the arte- rial pipe must be fixed into its principal trunk or trunks: and 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, whereby all the ramifications being inflated, such as are cut can be thus easily found out and secured. XX11 INTRODUCTION. 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 a profusion of adeps blending itself with the muscles, and not unfrequently of a diseased state of the arterial sys- tem. In dried preparations the arteries should be fairly traced in all their ramifications, and the muscles sepa- rated from each other. Every thing not essential to the object of the preparation must be cut away. When the part is fully dissected, care should be taken to put every portion of it in a proper posture, and to fix it so till it becomes stiff by exposure to the air. The muscles are to be kept asunder by strips of wood. When the preparation is thoroughly dried, and not before, it should be varnished. But previously to the latter process, it 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 after- wards be washed with water to remove the soap that results from the application of the potash. Soap-boil- er's ley answers perfectly, in the place of the caustic potash of the shops. Dried preparations suffer much from insects, and the best security for them is obtained by immersion in a solution of corrosive sublimate, till INTRODUCTION. xxiii 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 four times advantageously with this mixture: Corrosive Sublimate gi. Muriate of Ammonia, giss. Water, fti. At the two last washings add to the foregoing. Common Glue, dissolved, gi. The glue makes the mixture adhere to the prepara- tion, and also furnishes for the varnish a basis or ground, 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 chosen in making cor- roded preparations. Their vessels, excretory ducts, and cavities, as the case may be, should be distended moderately with No. I. observing to give to each sys- tem in the structure of the viscus, a colour different from the rest. The successful injection of these re- quires good management, because, if too much force xxiv INTRODUCTION. be used, extravasation will occur and the preparation will be materially disfigured. After injecting it, 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 of the fresh, to bring it to its original strength. When the fleshy part is converted into a soft pulp, the preparation must be taken out of the mixture with the greatest care and subjected to a small gentle stream of water, which washes off the pulp and leaves the vessels bare. If the corroding process be unfinished the part must be replaced in the acid mixture and kept there till it is completed. On the pulp being removed, let the preparation remain floating in water for twenty four hours in order to remove any acid which may adhere to it; then dry it by suspension in the air or by laying it on a heap of soft carded cotton, covered with a thin cambric cloth, in order to prevent the cotton from sticking to its vessels. As corroded preparations break from the slightest violence, I have latterly used with great improvement to their strength, a size of isinglass, into which they INTRODUCTION. XXV were dipped; by repeated applications of this they be- come well coated with it, and thereby too strong to be injured by slight jars. The preparation should be fixed on a pedestal of plaster of Paris, 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 generally, and all morbid derange- ments, are proper subjects for wet preparations. The natural structure of many parts is also very advan- tageously displayed in this way. The article previ- ously to being put up, should be steeped in water changed daily, till all the blood is out. Spirits of wine, spirits of turpentine, and a solution of corrosive sublimate, are each excellent for suspend- ing such preparations in. The latter answers particu- larly well for eyes and for thin membranous parts, as an intestine, &c. Two grains of corrosive sublimate, with an equal quantity of muriate of ammonia, to an ounce of water, make a solution sufficiently antipu- D xxvi INTRODUCTION. trescent for an eye, and which contracts the prepara- tion much less than spirits of wine. When larger bodies are preserved the quantity of corrosive sublimate must be increased proportionately. 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 bladder; over this must be placed sheet lead, about the thick- ness of a quarter of a dollar, and trimmed so as to correspond in size with the top of the bottle; over this lead another piece of bladder is to be stretched and secured. The outside bladder, being properly trimmed, should be varnished twice with copal varnish 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 are the lymphatics and lacteals. In the extremities we introduce the pipe 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 INTRODUCTION. xxvii in the mesentery and inject backwards; as the lacteals on the intestine itself are, 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 injected with quicksilver, from its duct, affords a fine preparation. The injection 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 of the adult, are also excellent subjects for this kind of prepa- ration. The lactiferous ducts of the mammae are very favourably displayed in the same manner; they are in- jected separately from the nipple.* A woman who has died during lactation is the best subject for it. * Bristles should be previously introduced into each duct, and with- drawn successively as the injection advances, otherwise we may com- mit the mistake of injecting a duct twice. As each duct is injected, it should be secured with a ligature. xxviii INTRODUCTION. 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 remo- ved 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 seium. 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- solved 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 properly conduct- ed no bleaching is necessary; if otherwise, the process adopted in whitening linen and cotton clothing answers well, that is, exposure to the sun, frequent wetting with water, and chlorine. INTRODUCTION. xxix 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 only of bone, 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 foetus, or of a young child, and fix a pipe into the principal artery. By filling the part with the size injection, the vessels of the bone will also be injected. * The acid is to be renewed from time to time. XXX INTRODUCTION. 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 part is 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. It is called the Guyto- nian from its inventor. Take Manganese or peroxyd of 1 part Common salt 7 parts Water 4 parts Sulphuric acid at 66° 4 do each by weight. The water and the acid should be previously mixed 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. * For a very valuable and instructive exposition in detail, of the art of making anatomical preparations; I would recommend the treatise on this subject by Usher Parsons, M. D., Professor, &c. INTRODUCTION. XXXI The next morning it will be found much sweetened, and on ventilating freely, its atmosphere will lose still more of its offensiveness and be in a great measure renovated. 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. A milder fumigation which may be used beneficially in sick chambers is obtained by pouring in successive portions, five parts of hydrochloric acid upon one of peroxyd of manganese. Students of Anatomy have their fears much excited on the score of the constitutional symptoms, arising from small wounds inflicted during their dissections; under an erroneous impression, that a spe- cific virus is, thereby, introduced into the system. Inconveniences of this kind, though they do occasionally occur, are by no means fre- quent; and are just as apt to be produced from the prick of a needle, of a brier, or of an oyster-shell. The first intimation of such mischief, is the part becoming painful, red, and swollen, and the arm getting somewhat stiff; if in the early stage of these symptoms, a blister be applied according to the recommendation of Dr. Physick, the person live lightly, and take a saline cathartic, the treatment is almost invaria- bly sufficient for the cure. Such accidents are much more liable to occur from the prick of a spicula of bone, than from any other cause to which the Anatomist is exposed, furnishing thereby, a useful hint for him, never to break a bone, but always to saw it off smoothly. \ t 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 cranium are remarkably thick and hard, but give the sensation, when felt externally, 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 cel- lular substance; which has very much of a ligamen- tous character, and adheres closely to the muscle and tendinous matter beneath. The muscles of the face should always be dissected as early as possible after death; under the most 1 2 OF THE HEAD AND NECK. favourable circumstances they are difficult for the student to make out, and are rendered unintelligible to him in a few days by the changes which their diminution of volume, infiltration, and confusion of colour with contiguous parts, produce. I would also advise that one side of the face and neck 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; it is of less importance to inject the veins. It is unnecessary to heat the subject for such injection. SECTION I. Of the Muscles and Fascial. 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, M-USCLES AND FASCIAE. 3 from the close adhesion of its tendon to the pericra- nium below, and to the integuments of the head above. It is best, therefore, to commence by making one incision, through the integuments only, from the root of the nose to the fore end of the sagittal suture, and another from the commencement of the first along the upper margin of each eyebrow to the external angular process of the os frontis; by raising up this flap and enlarging it in an appropriate manner on each side, it leads to the dissection of the whole muscle. It arises from the superior semicircular ridges 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 carefully 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 su- percilii, and by its nasal slip into the internal angular process of the os frontis and into the root of the os nasi. It pulls the skin covering it 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- 4 OF THE HEAD AND NECK. ning from the root of the ala nasi; it spreads like a fan over the lateral parts of the nose below, is inserted into its fellow of the opposite side, on the dorsum of the nose; and into the lower part of the os nasi, where it is connected with the nasal slip of the occipitb frontalis. This muscle consists of thin and pale fibres imme- diately under the skin. If it act from both extremities by its curved fibres being made straight, it will compress the nostril; but if it act from its dorsal margin 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 circular muscle lying immediately under the skin of the eyelids, 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 fastened to the temporal fascia beneath. It arises fleshy from the internal angular process of the frontal bone, from the upper end of the nasal pro- cess of the os maxillare superius and the os unguis, and from the upper edge of the round horizontal tendon called internal palpebral ligament that fixes the internal commissure of the eyelids to the nasal process of the superior maxilla. These fibres perform the circuit of the eyelids, and, coming around to the internal canthus MUSCLES AND FASCIAE. 5 again, are inserted into the orbital margin of the nasal process, and of the orbitar process of the upper maxilla, and into the lower edge of the same horizontal tendon. 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 portions more than elsewhere, it is obvious that the contraction of its circular or curved fibres by making 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 internal 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^q,ue Nasi is fixed just at the side of the nose. It arises by a pointed production from the nasal process of the os maxillare superius near the internal canthus of the eye, and by a broad origin from the anterior margin of the orbitar process of the same bone. Passing 6 OF THE HEAD AND NECK. downwards it is inserted into the side of the ala nasi, and into the upper lip, being narrower below than above. It draws the upper lip and the ala nasi upwards. The Levator Anguli Oris is a small muscle con- cealed very much by the last; it arises from the anterior part of the superior maxillary bone, between the foramen infra-orbitarium 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 malse; it descends obliquely and is inserted into the upper lip just above the corner of the mouth. The Zygomaticus Major, being on the outside 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 is inserted into the corner of the mouth, by 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 Superiors AljEciue Nasi is MUSCLES AND FASCIJE. 7 concealed by the orbicularis oris and by the levator labii superioris ateque 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 frgenum of the lip. This muscle arises from the inferior part of the upper maxilla in front of 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 levator anguli oris. The Depressor Labii Inferioris is in part beneath 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 being mixed with a quantity of adipose matter; the skin, also, 8 OF THE HEAD AND NECK. is closely blended with them, and the roots of the beard penetrate between the intervals of their fibres. The Levator Labii Inferioris, being placed beneath the depressor labii inferioris, is demonstrated by turn- ing downwards the lower lip and dissecting away its lining membrane on the side of the frsenum; It will then be seen to arise in front of the alveolar process of the external incisor and the canine tooth of the lower jaw, and passing obliquely downwards to be inserted into the lower lip. 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 pro- cess 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 considerable part of the thickness of the lips, and MUSCLES AND FASCIiE. 9 surrounds 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 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 maxilla, and from the inferior edge of the malar bone between 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 extends 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 zygomatic suture behind the external, without the latter being raised up. It closes the jaws. 2 10 OF THE HEAD AND NECK. The Temporalis lies* on the side of the head occu- pying its middle inferior region; it is covered externally by a thick dense tendinous membrane, the fascia temporalis, which arises from the semicircular 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, between this ridge and the zygoma including a part of the frontal bone, the lower part of the parietal, and the squamous portion 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. This is a proper place also for looking at the Ptery- goid 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 vertebrae, which can be done very conveniently when we are engaged in the study of the nose, or of the pha- rynx. MUSCLES AND FASCIJE. 11 The Pterygoideus Externus arises fleshy from the outer side of the external pterygoid process of the sphenoid bone, from the tuber of the upper maxillary, and from the under surface of the temporal and spi- nous process of the sphenoid bone. It passes out- wards and backwards horizontally, and is inserted into the inner side of the neck of the inferior maxilla and into the capsular ligament of the articulation. The Pterygoideus Internus arises by tendinous and fleshy fibres from the internal plate of the ptery- goid process of the sphenoid bone, at the outer side of the Eustachian tube. It fills up the most of the pterygoid fossa, and passing downwards and back- wards, is inserted tendinous and fleshy into the interior face of the angle of the lower jaw. Both of these muscles are important in mastication; they close the jaws, throw the lower one forward, and produce the grinding motion by acting alternately. Of the Muscles of the Neck. The dissection of this part can now be advantageously pursued; with which 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 sternum, and a third from the chin to the upper part of the ear. The flap thus marked out is to be raised carefully without cutting up a superficial membrane that lies below the skin called Fascia Superficialis. 12 OF THE HEAD AND NECK. The Fascia Superficialis Cervicis or Colli is a con- tinuation of the one placed in front of the abdominal muscles, and which passes from them to the thorax and afterwards to the neck. Its connexion 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 audi- torius, and to the zygoma; in the latter place it is con- tinuous in some measure with the fascia temporalis. The existence of this membrane is thought, by Mr. Colles of Dublin, to obscure the affections of the neck and of the parotid gland, by checking the development of tumours, rendering their fluctuation and particular feel very equivocal, and giving a wrong course to the pus when they suppurate. The fascia superficialis is better marked over the parotid gland, and about the base of the jaw, than lower down. The Platysma Myodes muscle, or the Musculus Cutaneus, is immediately beneath the fascia superfici- alis, or rather is between two laminae of it, the thicker one being the innermost. It covers a very consider- able portion of the side of the neck, and extends 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 MUSCLES AND FASCIA. 13 length of this bone. Its fibres are much more pale than those of other muscles, are collected into longitudinal 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 runs 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 nearly in the centre of it, in the same direction with the fibres of this muscle, between it and the sterno- mastpid. The Sterno-Cleido-Mastoideus is beneath and decussates the last muscle. It forms always a promi- nent feature in the outline of the neck, by passing obliquely 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 ster- nal end of the clavicle. These origins are separated by a considerable fissure; they soon unite and are inserted tendinous into the mastoid process and into that part of the superior transverse ridge of the head next to it. It draws the head towards the sternum. This muscle 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, hand- 14 OF THE HEAD AND NECK. some ribbon-like muscles on each side of the middle line of the trachea; they are the sterno-hyoideus and sterno thyroideus. But before we go to the dissec- tion of them, it is necessary to look at another fascia of the neck; the Fascia Profunda Colli or Cervicis. When the origin of the sterno-cleido mastoideus is turned to one side, the Fascia Profunda of the neck is brought into view. This membrane arises from the larynx, forms a thin capsule to the thyroid gland, and being closely attached to its inferior margin, it descends by investing the sterno-hyoid and thyroid muscles, being well mark- ed on their anterior surfaces. It is firmly fastened to the upper edge of the sternum, the sternal end of the clavi- cles, and to the cartilages of the first ribs, forming an elastic and resisting membrane from the larynx t6 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 be- hind them from the inferior margin of the thyroid gland to the upper bone of the sternum, this lamina of it being inserted into the sternum twelve or fifteen lines below its upper edge. It encloses or surrounds the trans- verse vein and the arteria 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 placed at the lower part of MUSCLES AND FASCIA. 15 the neck beneath this fascia, between it and the tra- chea, and through which the thyroid veins with their ramifications pass. This last circumstance must always render suppurations and operations in the part highly dangerous, as the pus may form fistulae under the sternum; moreover, the continual motion of the part in respiration prevents adhesion from occurring, 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, with- out them, would fall upon the trachea, and produce difficulty 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 place. * The external borders of the fascia profunda are * The late Dr. Jason O. B. Lawrence, who, to the great regret of all who knew him, died prematurely, in" 1823, in the midst of his la- bours and usefulness in anatomy, informed me that this fascia pro- funda is well developed in the neck of a cat; and that having occasion to remove it in an experiment, the respiration of the animal was con- ducted with great difficulty, amounting almost to suffocation. This is a good confirmation of Mr. Burns's hypothesis. 16 OF THE HEAD AND NECK. 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, is a liga- mentous expansion connected with the pterygoideus externus muscle, and spread out between the styloid process and the ramus of the lower jaw. This mem- brane called the stylo-maxillary ligament, is joined with the fascia superficialis at its inferior edge just before the upper part of the sterno-mastoideus, whereby its breadth is increased 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 cellular sheath of the great vessels of the neck. Through its lower part, penetrate the stylo-hyoideus and the digas- tricus muscle, and the upper part separates the parotid from the submaxillary gland. It is felt like a cord ex- tending downwards and backwards 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 the practical anatomist will find no difficulty in dis- covering and understanding it. 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 on the MUSCLES AND FASCIAE. 17 interior of the thorax from the approximated surfaces 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. Jt draws the os hyoides towards the sternum. The Sterno-Thyroideus is beneath 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 cartilage of the first rib; diminishing in breadth somewhat as it ascends, it is inserted obliquely into the side of the thyroid cartilage. It draws this cartilage towards the sternum. The Thyreo-Hyoideus arises obliquely from the side of the thyroid cartilage externally, and is inserted into a part of the base and nearly all the cornu of the os hyoides. It looks like a continuation of the last. Use; To draw up the thyroid cartilage. The Omo-Hyoideus passes obliquely across the neck from the superior edge of the scapula to the os hyoi- des. 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 ves- sels of the neck and is covered by the sterno-cleido- 3 18 OF THE HEAD AND NECK. mastoid muscle, and its upper extremity is over-lapped by the platysma myodes. It arises from the scapula just behind the notch in its superior costa, and curving somewhat downwards in its course is inserted into the lower edge of the base of the os hyoides next to its cornu. It draws 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, principally fleshy, from the fossa of the temporal bone at the in- side of the mastoid process; as the muscle descends towards the os hyoides, its middle part is formed by a round tendon which passes through the stylo-hyoideus muscle, and is fixed, by a ligamentous loop, to the cornu of the os hyoides. After this the - muscle be- comes again fleshy, and is 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 hyoides. 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 inferior' part of the styloid process of the temporal bone, and being perforated, as mentioned, by the tendon of the MUSCLES AND FASCLE. 19 digastricus, is inserted tendinous into the cartilaginous juncture of the base and cornu of the os hyoides. 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 thereby 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 inside of the pharynx between the middle and upper constrictors, opposite the tonsil gland. It afterwards continues between the lining membrane of the pharynx and the middle and lower constrictors, to the posterior margin 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, extend- ing from the last dens molaris to the chin. Its fibres converge inwards, and are inserted into the correspond- ing fibres of the opposite side by a white tendinous line placed between it and its fellow, and extending from the base of the os hyoides to the chin. This 20 OF THE HEAD AND NECK. muscle lies above, so as to be concealed by the anterior belly of the digastricus, and when it contracts it draws the os hyoides upwards, and projects the tongue. The Genio-Hyoideus is immediately above the last, by turning down the anterior edge of which, it is seen. It arises tendinous from the tubercle on the posterior side of the symphysis of the lower jaw, 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 tendi- nous from the tubercle on the inside of the maxilla in- ferior, 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 muscles 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 down- wards. The Lingualis may also be seen in part in this dis- MUSCLES AND FASCIA. 21 section. It is one of the intrinsic muscles of the tongue, and lies on the inner side of the last. For a further account of the muscles of the tongue, see the article Mouth. There are four pairs of muscles situated behind the pharynx and oesophagus, close to the cervical vertebras, which can only be seen imperfectly in this dissection. 1. The Longus Colli is next to the middle line of the vertebras, and arises from the sides of the bodies of the three superior vertebras of the back, and from the anterior edges of the transverse processes of the five lower cervical vertebras. Its fibres pass somewhat obliquely upwards and inwards, to be inserted into the front of the bodies of all the cervical vertebras. It bends the neck forwards, and to one side., 2. The Rectus Capitis Anticus Major arises ten- dinous and fleshy from the fronts of the transverse processes of the third, fourth, fifth and sixth cervical vertebras, 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 Anticus Minor arises fleshy from the front of the first cervical vertebras near its transverse process, and is inserted under the rectus 22 OF THE HEAD AND NECK. major before the root of the condyloid 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 out- side 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 vertebras to the upper parts of the thorax, are the Scaleni muscles, three in number, and 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 vertebras, and is inserted tendinous and fleshy into the upper edge of the first rib, just anteriorly to its middle. 2. The Scalenus Medius arises by distinct tendons from the transverse processes of all the cervical verte- bras, and is inserted tendinous and fleshy into the upper part of the first rib, in all the space from its middle to its tubercle. 3. The Scalenus Posticus arises from the transverse MUSCLES AND FASCLE. 23 « processes of the fifth and sixth cervical vertebrae, and is inserted into the upper face of the second rib just anterior to 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 Scale- nus 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 connected 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. SECTION II. Of the Glands of the Head and Neck. The Thyroid Gland, (Gland. Thyroidea,) consist- ing of two lobes united by an isthmus, is placed on each side of the upper part of the trachea, and extends upwards laterally by the cricoid cartilage to the thy- roid. It resembles a pair of saddle-bags in its general outline; the upper edge, however, being very much ex- 24 OF THE HEAD AND NECK. cavated or crescentic, with the horns pointing upwards. The isthmus passes over the second ring of the tra- chea, and is firmly fixed to it by a short cellular sub- stance. Duverney and Soemmering in their plates represent a muscle, passing on the left side of the larynx, from the base of the os hyoides to the upper edge of the thyroid gland, to which they give the name of Musculus Glandulas Thyroideas. Its occurrence in this country is, I presume, exceedingly rare, as out of several hundred subjects which I have superintended the dissection of, but few examples of it have been noticed. It may be observed, however, that a process of the isthmus looking like a muscular slip is frequently formed on the left side, and goes up to the base of the os hyoides, and that sometimes a few filaments are detached to the gland from the thyreo-hyoid or crico- thyroid muscle. 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 commu- nicating with each other, of different sizes, and con- taining an unctuous and somewhat transparent fluid, and that it has no excretory duct. MUSCLES AND FASCIiE. 25 On each side of the neck are three large salivary glands, the Parotid—the Submaxillary—and the Sub- lingual. The Parotid Gland (Glandula Parotis) is the most considerable of the three, and its form is very irregu- lar, depending on the space into which it is crowded. It reaches from the zygoma downwards to the angle of the jaw, occupying the space from the mastoid pro- cess and meatus auditorius to the ramus of the jaw, and extending from the skin externally to the styloid process, styloid muscles, and the tendon of the digas- tricus internally; it is there only separated from the internal carotid artery by these parts internally; its connexions are numerous and exceedingly intricate. It is removed in the dead subject from the contiguous parts with great difficulty, and in the living subject its complete and safe extirpation is nearly impracticable. The portio dura nerve and the external carotid have to penetrate directly through its substance 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 pro- longations are sent off, which penetrate the gland in every direction, separating its lobules from each other and conducting the blood-vessels and nerves through its substance. The substance of the gland is formed of small rounded granulations of a light pink colour, 4 26 OF THE HEAD AND NECK. united into lobules of various forms; an arteriole 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 proceeds the parotid duct across the masseter muscle, about eight lines below the zygoma; and according 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, {Ductus Stenonianus^) is about the size of a crow quill; it arises from the granulations of the gland, by ramuscles which, unite successively, to form it. The gland is sometimes divided into two lobes, in which case each has an excretory duct that joins the other, half an inch in front of the an- terior edge of the gland. The common duct lies close to the masseter muscle, and may easily be overlooked by the young anatomist; forwards 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. Sometimes at the posterior part of this duct, between it and the zygoma, a small gland is situated, varying in its size and form, and called by Haller the accessory of the parotid. The Submaxillary Gland {Gland. Sub-Maxillaris) is irregularly ovoid. It is situated below the Platysma MUSCLES AND FASCLE. 27 myodes in the space bounded by the digastric muscle below, the mylo-hyoid towards the mouth, and the body of the lower jaw externally—and is in contact with the facial artery. It almost touches the parotid gland behind, being separated from it only by the sep- tum sent in from the fascia superficialis; and at the posterior edge of the mylo-hyoideus it touches the sub- lingual gland. Its structure is the same with that of the parotid gland, except the capsule of cellular membrane with its internal prolongations, being much looser. It has an excretory duct, {Ductus Whartonianus,) arising in the same way by ramuscles, but much thinner and more extensible than the parotid duct; it penetrates between the back edge of the mylo-hyoid and the hyo- glossus muscle, and continues between the genio-hyo- glossus and the sublingual gland; from the latter it re- ceives occasionally several branches; it terminates by an orifice on the side of the fraenum linguae near its anterior edge. The Sublingual Gland {Glandula Sublingualis) is placed under the lining membrane of the mouth be- tween the side of the tongue and the mylo-hyoid mus- cle, and being oblong it is parallel with the genio-hyo- glossus where the latter is about to join the tongue. This gland is not uniform in the arrangement of its excretory ducts. Sometimes it has fifteen or twenty excretory orifices in the lining membrane of the mouth; 28 OF THE HEAD AND NECK. on other occasions several of these short ducts are collected into one or two principal trunks .{Ductus Riviniani) 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 painful swellings in the neck, which most frequently are en- larged 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 number; 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 superficial 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 jugu- lar 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 several asserted cases of extirpation of the parotid and MUSCLES AND FASCLE. 29 of the submaxillary gland, have amounted actually only to the removal of some of these lymphatic glands in a state of enlargment. 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 ar- teria 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 vertebras 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 the external carotid; the 30 OF THE HEAD AND NECK. first is intended for the brain, and the last for the ex- ternal parts of the neck and head. In the lower part of the neck the carotid is covered by the sterno-hyoi- deus and thyroideus and the anterior edge of the sterno-cleido-mastoideus, and at an inch and a half below its bifurcation it is crossed obliquely by the omo-hyoideus muscle. This point may be ascertained before the skin is opened by a horizontal line drawn across the neck over the first ring of the trachea, and consequently below the larynx. In its whole course it is joined with the par vagum, sympathetic and descen- dens noni nerves. Parallel with the larynx the carotid may be felt pul- sating very distinctly, being there covered only by the platysma myodes. It is contained in a sheath of con- densed cellular membrane commom to it, the internal jugular vein and the par vagum nerve. The External Carotid, (Carotis Externa) at the place of bifurcation, is interior and anterior to the in- ternal carotid, and it immediately begins to send off branches in the following order: 1. The Arteria Thyroidea Superior passes in a meandering direction to its principal destination the thyroid gland, through which it is minutely distributed 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, between MUSCLES AND FASCIAE. 31 the os hyoides and thyroid cartilage and also some twigs to the same between the thyroid and cricoid. It sends off some smaller branches to contiguous parts. 2. The Arteria Lingualis arises just above the last; it goes very near the cornu of the os hyoides, by penetrating the hyo-glossus muscle. At the root of the tongue it sends off a transverse branch (the Dor- salis 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 Arteria 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 muscle. It is much involved 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 tortuous and surround the mouth, anastomosing freely with those of the other side. After this the facial artery ascends to the internal 32 OF THE HEAD AND NECK. 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 anastomoses with branches from the ophthalmic and then 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, and arises op- posite 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 insertion of the muscles going to the mastoid pro- cess, and is distributed to the parts lying on the occip- ital bone; its upper branches anastomose with those of the temporal artery. Its collateral branches are, one to the dura mater through the posterior foramen lacerum, or the mastoid foramen, 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-Mas- toidea, arises from the carotid at the lower edge of the parotid gland, and passes backwards and upwards between the meatus externus and the mastoid process, MUSCLES AND FASCIA. 33 to terminate behind the ear. It is distributed princi- pally to the contiguous superficial parts but, one branch goes up the stylo-mastoid foramen, to the tympanum and to the labyrinth. The External Carotid, while detaching 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 twigs. It ascends through the gland and exhibits itself superficially just before the meatus externus, in mounting over the root of the zygoma. When 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 ramus 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 goes to the side of the head; while it is still bedded in the parotid, it sends off the Transversalis Faciei, which crosses the masseter muscle below the Parotid Duct, and is distributed to the contiguous parts. The temporal artery then rises over the zygoma, where a branch leaves it which pen- etrates the temporal fascia, and is distributed to the muscle beneath; this is the Middle temporal artery. The temporal artery having got an inch or so above 5 34 OF THE HEAD AND NECK. the zygoma, divides into an anterior and a posterior branch. The first is distributed forwards on the tem- ple, inosculating with its fellow of the other side, and with the facial and the ophthalmic artery. The second is distributed laterally on the parietal region, also anas- tomosing 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 surface of the temporal bone. It passes between the internal and external pterygoid muscles immediately after leav- ing the carotid' artery; and sends off 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 foramen spinale. From this trunk sometimes pro- ceeds the lesser meningeal to the dura mater through the foramen ovale. 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 posterior deep, the second the anterior deep tem- poral artery. MUSCLES AND FASCIA. 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 molar teeth of the upper jaw. 9. The infra orbitar, through the infra-orl?itar canal, to the canine and incisor teeth, and to the cheek. 10. The palatine artery through the posterior pala- tine canal to the soft palate. 11. The superior pharyngeal artery to the upper part of the pharynx. 12. The spheno-palatine, which is the terminating branch of the internal maxillary artery, and is very minutely distributed to the Schneiderian membrane by two trunks, one on the septum of the nose, and the other on its external side. The Internal Carotid Artery, (Carotis Interna) at its commencement, is generally dilated like an in- cipient aneurism; it curves much in getting to the fora- men caroticum and is in contact with the par vagum and sympathetic nerves; it sends off no intermediate branches. In the canal, it gives a branch to the tym-- panum, and as it lies on the side of the sella turcica, it gives the anterior and posterior arteries of the ca- vernous sinus. Its subsequent history is merged in that of the ophthalmic and cerebral arteries. 36 OF THE HEAD AND NECK. The following arteries belonging to the neck, are de- rived from the subclavian, as it is about to get between the scaleni muscles. 1. The Arteria Vertebralis which goes into the canal of the transverse processes of the vertebrae of the neck at the sixth, and, following its course, enters the fo- ramen magnum occipitis to be distributed to the brain. It is very tortuous at the first and second vertebrae. 2. The Arteria Thyroidea Inferior, which passes up obliquely to the thyroid gland between the great vessels of the neck and the vertebras; in its distribution it anastomoses very freely with the other thyroid arte- ries. This artery generally sends off The Cervicalis Anterior, a small artery, which is distributed along the course of the scaleni muscles, and which comes frequently from some other branch of the subclavian. 3. The Cervicalis Posterior; it is very tortuous, and runs horizontally across the root of the neck, to the trapezius muscle and the subjacent ones. It arises most frequently, either from the subclavian or the in- ferior thyroid. The veins of the face and external parts of the Head correspond so much with the distribution of the arte- MUSCLES AND FASCIiE. 37 ries, that they may be considered as having nearly the same course; to undertake the description of them, therefore, would be almost a repetition of what has been said. Towards the angle of the jaw they are collected into a common trunk, the external jugular (Jugularis Exter- na,) which crosses obliquely the sterno-cleido-mastoid muscle under the platysma myodes 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 ex- ternal jugular, almost immediately after its formation, joins the internal jugular. On other occasions the fa- cial vein joins the external jugular; and the temporal vein, with slight accessions from the side of the face, forms a trunk which descends almost vertically under the platysma myodes and outside of the sterno-cleido- mastoideus to join the subclavian vein in front of the scaleni muscles. The varieties are, in short, too nu- merous to be recounted in this work. The Internal Jugular Vein (Jugularis Interna) may, with propriety, be considered as the great venous trunk of the brain, being a continuation of the lateral sinus. It lies on the outside of the internal and of the common carotid artery, enclosed in the same sheath, descends into the upper mediastinum in con- tact with the pleura, and is joined at the internal edge 38 OF THE HEAD AND NECK. of the scalenus anticus muscle by the subclavian vein. This jugular vein is occasionally much dilated, and in the contractions of the right auricle, spreads over the carotid artery. One vein is sometims much larger than the other. The Upper Thyroidal Veins discharge into the in- ternal or external jugulars; the Lower Thyroidal Veins into the transverse or subclavian veins; sometimes 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 thyroidal veins discharge in whole or in part. The variety of ar- rangement 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 under- taken by the young student; to perform it successfully requires much time, patience, and address; when, by advanced study, the two latter are obtained, the labour will be fully compensated, by the pleasure and infor- mation it affords. For a very minute dissection a NERVES. 39 lean subject is indispensable; for a commnn one, it is less important, and much of this dissection may be performed on the subject appropriated to the arteries. The Portio Dura comes out at the stylo-niastoid 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, send- ing branches to the temple which join those of the su- pra-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 part of the neck, which join those of the superior cervical nerves. The distribution of this nerve is too minute to admit 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 com- menced at the stylo-mastoid foramen, or in the parotid gland, and the skin should be raised only as its branches are exposed; without this precaution the dis- section 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 entire- ly, observing to leave the pterygoid muscles by cutting close to the bone through their insertions; when the 40 OF THE HEAD AND NECK. adipose and cellular membrane is then cleared away, the second and third branches of this 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 foramen 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 face. This is the infra-orbitar nerve, which, just be- fore entering the canal, sends off the Posterior Dental Nerve to supply the three last molares, and afterwards sends off the Anterior Dental Nerve to supply the ca- nine, and incisor teeth. The Bicuspate teeth are sup- plied by an union of filaments from the anterior and posterior dental nerves. Afterwards, the Superior Maxillary Nerve passes downwards in two divisions, sometimes to a level with the spheno-palatine foramen, and forms the spheno- palatine ganglion, or the ganglion of Meckel, from which proceed the Pterygoid, the Lateral Nasal, and the Palatine Nerves. The Pterygoid Nerve, retrograding through the fo- ramen of the same name, gets into the cavity of the NERVES. 41 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 the vidian foramen has a singular course through the ear. (See Chorda Tympani.) The Lateral Nasal Nerve consists of several fila- ments from the spheno-palatine ganglion; getting into the nose they are distributed to the pituitary, mem- brane 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 M. J. Cloquet, forms a ganglion with its fellow near the bottom of the canal. With this ganglion communicate branches of the palatine nerve. The Palatine Nerve passes through the posterior palatine canal to the roof of the mouth; it there divides into filaments supplying the lining membrane, the soft palate, the uvula, and the tonsils. In its way down- wards, it sends several small twigs to that portion of the pituitary membrane which covers the inferior 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 imme- 6 42 OF THE HEAD AND NECK. diately 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 Superficial Temporal, the size of a knit- ting-needle, which joins the portio dura, 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 section of the portio dura for tic doloureux. The Second Branch of the Inferior Maxillary Nerve passes between the pterygoid muscles and divides 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 Inferior Maxillary Nerve. The first in its progress between the ptery- goid muscles is joined by the chorda tympani; it then 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 papillas. The in- ferior maxillary nerve enters the posterior maxillary foramen; but while doing so despatches a branch, the Mylo-hyoid, to tne submaxillary gland and the muscles under the jaw; it then goes in a canal in the spongy part of the bone. Very frequently it divides into two branches, the upper of which is literally the dental nerve, and is spent by dismissing ramifications to all the teeth successively. The nerve below, however, remains to come out, at the anterior maxillary foramen, and is spent on the chin. NERVES. 43 In order to proceed properly in the dissection of the Nerves of the Neck, the skin must be carefully raised from the sterno-cleido-mastoid muscle; by 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 distributed on the anterior edge of the trapezius muscle. By detaching next the sterno-mastoid muscle from its origin and turning it aside, the spinal accessory nerve will be seen, coming from the posterior foramen lacerum where it adheres to the Par Vagum, Glosso- pharyngeal and Ninth Nerve; and passing obliquely behind 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 nervous filaments is seen upon the neck going to its muscles, integuments and other parts, attd 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, therefore, for the at- tention 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 condensed cellular membrane; it passes to the tongue between the stylo-glossus and stylo-pharyngeus muscle, and 44 OF THE HEAD AND NECK. on the outside of the internal carotid artery. Follow- ing the course of the stylo-glossus muscle at its in- ternal 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 mem- brane. 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 mem- brane, it abandons the par vagum by getting between the internal carotid artery and the internal jugular vein, and crossing them obliquely about half an inch be- low the glosso-pharyngeus muscle. It descends much lower in the neck than the glosso-pharyngeal, forming a large curve with the convexitv downwards. It is the nearest large nerve below the glosso-pharyngeal, the order of descent being first the lingual branch of the fifth pair, the glosso-pharyngeal second, and the ninth nerve third. In its descent the Ninth nerve winds externally around the external carotid artery, just below the ori- gin of the occipital artery. Here it is below the pos- terior belly of the digastricus, and the stylo-hyoideus. It then passes forwards somewhat horizontally under the external jugular vein towards the root of the tongue, where it is at the side of the hyo-glossus muscle a NERVES. 45 little above the os hyoides, and crossed externally by the stylo-hyoideus and the tendon of the digastricus. It now ascends on the inside of the mylo-hyoideus, and divides abruptly info many ramifications distributed to all the muscles of the tongue, from the space between the genio-hyo-glossus and the lingualis muscle. Where the Ninth nerve winds externally around the external carotid, it dismisses the Descendens Noni. The latter descends externally along the common ca- rotid, connected with its theca as far as midway be- tween the sternum and os hyoides; and unites with ramifications from the first, second, and third cervical nerves, to form a bow under the sterno-mastoid muscle. Above this bow the descendens noni detaches branches to the upper parts of the sterno-hyoid and thyroid mus- cles, and from the bow branches proceed to the lower parts of these muscles. The Par Vagum, an important 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 nerve and to the superior cervical ganglion of the sympathetic. It then leaves them after a short dis- tance, assumes the position, just expressed, and main- tains it down the neck till it reaches the upper margin of the thorax. 46 OF THE HEAD AND NECK. Shortly after quitting the cranium, it sends to the middle constrictor of the pharnyx, 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 thyreo-hyoid membrane into an internal and ex- ternal branch. The former being the largest and above, proceeds between the os hyoides and the thyroid cartilage under the thyreo-hyoideus muscle, to the inter- nal parts of the larynx where it is distributed by minute ramifications to the arytenoid muscles, epiglottis and lining membrane. The external branch descending, is disposed of by ramifications 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 carotid, and passes before the subclavian artery on the right side, and before the aorta on the left. Immediately after passing these vessels it divides into an anterior and a posterior trunk; the first is the continued 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 as- cends to the larynx, sending branches to the trachea; NERVES. 47 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 su- perior. The Laryngeus Inferior has branches connecting it with the inferior cervical ganglion of the sympathetic; the cardiac plexus; and the pulmonary plexus of nerves. The Nervus Sympatheticus is also on the back part of the great vessels of the neck close to the vertebras; it is commonly said to be in their sheath; this, how- ever, 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 carotid 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 chord is close to the eighth and ninth nerves and oppo- site to the second cervical vertebra, it swells out into the Superior Cervical ganglion; it then descends, and, opposite to the space between the fifth and the sixth cervical vertebrae, it forms the Middle Cervical Gan- 43 OF THE HEAD AND NECK. glion, which is much smaller and more irregular than the first. The sympathetic is traced with some diffi- culty from this, in consequence of 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 vertebra, where another enlargement occurs, denominated Inferior Cervical, or First Thora- cic Ganglion. The first Ganglion is increased by filaments from the sub-occipital, the first, second and third cervical nerves. The second Ganglion receives filaments from the fourth, fifth and sixth cervical nerves. The Third Ganglion receives filaments from the sixth and seventh cervical, and the first dorsal nerves. From these ganglions proceed the cardiac nerves. The Nervus Phrenicus is a small, straight, insulated 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 distance 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- cipital, after its ganglion is formed by the posterior NERVES. 49 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 pro- cesses of the cervical vertebras, and is immediately divided into an anterior and a posterior branch. The posterior branches are distributed to the muscles and to the integuments which lie on the posterior part of the cervical vertebras, but the anterior branches are va- riously disposed of. The sub-occipital and the three first cervical nerves have their anterior branches going principally to the muscles which arise from the trans- verse processes of the vertebras, 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 sca- pulae muscle. Filaments are also sent from the anterior branches of the cervical nerves which join with the spinal accessory nerve, the hypo-glossal, the portio dura, the sympathetic, and the phrenic in various ways, which are too numerous to be mentioned here. The Axillary Plexus, from which the nerves of the upper extremity are principally derived, arises from the anterior branch of the four inferior cervical nerves and of the first dorsal. These branches are much larger than the posterior, and emerge between the anterior and the middle scalenus muscle. They send some very small filaments to the lower and middle cervical ganglions of the sympathetic. 7 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 skull cap may be separated by a saw carried only through the external table just above the tips of the ears, and about an inch above the su- perciliary ridges. With the aid of an iron chisel, and a mallet, the bone is afterwards easily broken through and separated from the dura mater. Should the adhesion of the latter be great a common spatula is very well adapted to destroy it. Bichat breaks the skull-cap to pieces with a hammer and then removes it, which is a BRAIN AND SPINAL MARROW. , 51 much inferior mode to the other, and objectionable from the spiculae of bone made by it. The medullary mass placed within the cavity of the cranium is termed in common language Brain. It af- fords the following parts for separate examination. 1. The Membranes. 2. The Cerebrum. 3. The Ce- rebellum. 4. The Pons Varolii and the Medulla Ob- longata. 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 ante- rior 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 junction of the limbs of its cross at the internal occipital protube- rance. It is narrow before and broader behind, where it joins with the tentorium. The next process is the Tentorium, which forms an arch slightly convex above, and crescentic in its gene- 52 OF THE HEAD AND NECK. ral figure. It is connected to the horizontal limbs of the occipital cross, to the superior ridge of the petrous bones, and to the posterior clinoid apophysis on each side. Immediately under the centre of the tentorium and running towards the occipital foramen, is the Falx Minor. On each side of the sella turcica is a process of dura mater forming its lateral boundaries. At the anterior edge of the tentorium is the Foramen Ovale through which the crura of the cerebrum pass to the Pons Varolii. In the angle formed by the reflection of the internal lamina of the dura mater from the external, are some large cavities called Sinuses. The first is the superior Longitudinal Sinus, and is triangular; it commences by a small beginning near the crista galli having accord- ing to some a small vein from the nose joining it through the foramen caecum. It enlarges by a contin- ual accession of veins from the pia mater and termi- nates 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 strings called the Chordae Willisii;—and the veins of the pia mater running into it obliquely forwards, so as to pro- duce the effect of valves. In this sinus, and also under the dura mater near the top of the brain are many small bodies of various sizes, the Glandules Pacchioni, from a line or less to three or four lines in diameter. One of the largest of these bodies BRAIN AND SPINAL MARROW. 53 on each side, actually protrudes from the surface of the brain through the dura mater, and makes a deep pit into the parietal bone, near the sagittal suture. 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 fo- ramen 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 Fourth Sinus, formed by the inferior longitudinal sinus and a vessel from the interior of the brain called the Vena Galeni. The fourth sinus joins the superior lon- gitudinal sinus at the internal occipital protuberance where the general meeting of the vessels is called Torcular Hierophili. Around the pituitary gland, in the sella turcica, is the Circular sinus of Ridley; and at the side of 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 sympathetic which are traced with some difficulty. Its principal artery is from the internal maxillary, and passes through the foramen spinale, making the deep arborescent indentations in the parietal bones. There are some other branches derived from the internal 54 OF THE HEAD AND NECK. carotids and vertebrals. The veins accompany the ar- teries, and do not discharge into the sinuses except very partially. Within 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 coat, not dipping into the convolutions of the encephalon. 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 separating itself about the medulla oblongata and the contiguous parts, from the membranes between which it is placed. It lines the internal surface of the Dura Mater, having the same reflections as a synovial membrane, and se- cretes a 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 surface of its ventricles in a manner difficult to be understood without dissection. It is much thinner and more deli- cate in the cavities of the brain than exteriorly, and seems there more like a vascular net-work than a per- fect membrane. It is highly useful in conducting ves- BRAIN AND SPINAL MARROW. 55 sels 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 the manner which will be explained at the end of the chapter. Its veins, are all inserted into the sinuses of the dura mater, and therefore do not accompany the arteries. 2. The Cerebrum fills by far the greater part of the cavity of the cranium, and extends from the tento- rium and anterior basis of the cranium to the vault of the latter. It is partially divided above by the falx major, into two equal parts called Hemispheres, and below we see that each of these hemispheres is sub- divided into three lobes. The Anterior Lobe is upon the orbitar process of the frontal bone; the Middle Lobe is 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 indenta- tion, the Fossa or Fissura Magna Sylvii, formed by the posterior edge of the little wing of the sphenoid bone, which prescribes their boundaries. 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, dip- OF THE HEAD AND NECK. ping down to the bottom of them keeps their opposite faces in contact. If a section be made into the brain, it will be seen to consist of matter of different colours and consis- tence. The external matter, varies from a line to three or four in depth; is the Cineritious or Cortical; is of a yellowish red colour; somewhat less consistent than the other; and covers all the convolutions. Within the cortical is the Medullary or Fibrous Matter, which is of a white colour, with small spots or dots of red owing to the blood vessels. By separating the hemispheres, we see that just be- low the edge of the falx major they adhere together by the pia mater of the opposite sides. Dissect this ad- hesion through, which brings into view a broad expan- sion 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 convexities towards each other. Between these lines is a fossa called Raphe. Other lines not so distinct pass laterally and at right angles to the first two. By pulling the hemisphere still more from its fellow, we bring into view its edge, which laps over the corpus callosum and is separated from it by a fissure running the whole length of the latter. The hemispheres above the corpus callosum must now be removed with a sharp knife, whereby a view is got of the Centrum Ovale of Vieussens, and also of BRAIN AND SPINAL MARROW. 57 the connexion formed between the hemispheres by the Corpus Callosum. The centrum ovale is properly speaking the oval nucleus of medullary matter which is left wThen the cortical is scraped or cut away, but 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, also the roof of the lateral ventricles. By removing the corpus callosum, the Lateral Ven- tricles, one on each side, are brought into view. They are very irregular cavities consisting each of a cen- tral portion or body and three processes or cornua, and extend from the anterior to the posterior portions of the hemispheres. In the anterior lobe is the Ante- rior cornu separated only by the Septum Lucidum from its fellow. In the middle lobe is the Inferior or Middle Cornu passing in a winding direction downwards and forwards, and in the posterior lobe is the Posterior Cor- nu, also called Digital Cavity. In the anterior part of the lateral ventricle is the Corpus Striatum, a long convex body, broad before and coming to a point behind; it is cineritious or cortical externally and medullary within; when scraped the latter looks fibrous. At the posterior part of the-cor- pus striatum is the Thalamus Nervi Optici, a large convex body, the surface of which is medullary and the interior cortical; it has a node or tubercle on its upper anterior face, and three on its posterior side; they 8 58 OF THE HEAD AND NECK. are of different sizes in different subjects. Between the thalamus and the corpus striatum is a streak of medul- lary matter called Tasnia Striata. In the posterior cornu of the lateral ventricle is a rising called Hippocampus Minor; and in the inferior cornu is a larger rising the Hippocampus Major, pass- ing to its bottom and increasing in breadth as it de- scends. 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. This is a trian- gular arched body of medullary matter narrow before and broad behind, and extending from the anterior to the posterior extremity of the thalami. It commences forwards by two crura very much curved, with their concavity backwards, and which arise deeply from the sides of the thalami near their union with the corpora striata. These crura come afterwards into contact, increase much in breadth, conceal the thalami, and form the fornix, which posteriorly is lost in the back of the corpus callosum and the hippocampi majores. The angle formed by the back and lateral margins is elongated and accompanies the hippocampus major for some distance, in the form of a thin crus which is easily demonstrated by raising it on the knife handle. This crus is the Corpus Fimbriatum, or Tasnia Hippo- campi. The under surface of the fornix is called Lyra. The Septum Lucidum is fixed between the lateral ventricles, at their fore part; is connected above to the BRAIN AND SPINAL MARROW. 59 corpus callosum, and below to the fornix. It consists of two laminae with a cavity between them at their front, called 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, par- ticularly when there has been a small dropsical effu- sion into the ventricles, the septum looks like a contin- uation of the middle of the fornix, a lamina of it being contributed by the internal margin of each crus. Under the fornix and lining the cavities of the late- ral ventricles, as well as the other ventricles, is placed a delicate reflection of pia mater with many vessels in it, but so very thin that it can scarcely be raised up as a perfect membrane. This membrane 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 margin of the fornix, on each side, is placed a fold of it quite loose and floating, and consisting of a great congeries of small veins arid arteries. 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 for- nix 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, being a more complete membrane, is called the Velum Inter- positum. The fornix should now be raised with the velum in- 60 OF THE HEAD AND NECK. terpositum, by cutting through its anterior crura and turning it backwards, which gives a more perfect view of the thalami. From these bodies on the opposite sides being in contact, a kind of junction, the Commis- sura Mollis is formed by their convexities. Anterior to this junction, is a triangular space called Vulva. It is here that the lateral ventricles communicate, under the anterior crura of the fornix, with the third ventri- cle. The communication is 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 it is formed of the space between them. At its lower front part is an open way, the Iter ad Infun- dibulum, leading to the basis of the brain, and at its posterior part is the aqueduct of Sylvius, or the Iter e Tertio ad Quartum Ventriculum. The Tubercula Quadrigemina, or Nates and Testes, are situated at the posterior part of the thalami, the nates being above. They are each about three or four lines in diameter; consist 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 cerebellum, also called the Valve of Vieussens, which is inserted into their lower part. The Pineal Gland, a small conoidal cineritious body, is found on the top of the nates. It is commonly four ftnes in its longest diameter, and contains a small BRAIN AND SPINAL MARROW. 61 quantity of calcareous matter, feeling and looking like fine sand, which, however, is occasionally collected into one or more irregular masses a line in diameter. This sandy matter is the Acervulus Cerebri. The pineal gland is situated between the nates and the back of the fornix, being closely connected with the under surface of, and surrounded by, the velum inter- positum, 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 the Peduncle of the pineal gland, which goes from the latter to the anterior crus of the fornix. At the anterior part of the third ventricle, just be- low the crura fornicis, and seen between their curva- ture where they diverge, is the Commissura Anterior, a medullary band like a nerve near the corpus stria- tum, and passing from the lower anterior part of one thalamus, to the other. At the back part of the third ventricle just under the pineal gland, is the Commis- sura Posterior passing also from one thalamus to the other, and being a semicylindrical fold of medullary matter. The Valve of the Cerebellum, is seen by cutting off the posterior lobes of the cerebrum, removing the ten- torium, and dissecting away the pia mater just behind 62 OF THE HEAD AND NECK. and below the tubercula quadrigemina. It passes up as a broad lamina of medullary matter an inch wide, from the central part of the cerebellum to the inferior portion of the testes. By introducing a probe from the third ventricle through the aqueduct of Syl- vius, it will be seen that this valve forms the roof of the fourth ventricle; and that it is 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. When inverted it has the following parts uppermost. The anterior and the middle lobes of the Cerebrum; The two hemispheres or lobes of the Cerebellum; The pons Varolii or Tuber Annulare; and the Medulla Oblongata. The Cerebellum is remarkable for the difference between its size and that of the Cerebrum, as it occu- pies only the space between the tentorium and the posterior fossas of the basis of the cranium. It is di- vided into two hemispheres or lobes by the falx minor. Though covered by the same membranes, its appear- ance differs from that of the cerebrum in consequence of its convolutions being straight and thin, and re- sembling horizontal laminae. The latter are separated by fissures penetrating, from four lines to twelve, and thereby increasing the surface for the entrance and exit of the vessels. The upper surface of the cere- BRAIN AND SPINAL MARROW. 63 bellum is slightly convex corresponding with the con- cavity of the tentorium; The under surface has a double convexity corresponding with the double con- cavity in the inferior part of the occipital bone. The upper central part of it, just above the fourth ventricle is called vermis superior; and when the two hemi- spheres are separated below, a prominence like a third lobe is seen between them, and is the vermis inferior. This central part of the cerebellum is the fundamental portion of Gall. When the cerebellum is cut into, the medullary matter is found principally in its centre, and sends off processes in every direction into the cortical. From this circumstance the medullary matter has an arbo- rescent outline upon all vertical sections made into the cerebellum and has obtained the name of Arbor Vitas, which is merely expressive of this arrangement with- out designating any particular part of it. If horizontal cuts be made the arbor vitas resemblance is not mani- fested, and the proportion of medullary matter appears more considerable. The two Crura of the cerebellum one on a side pass from the medullary portion, being in fact a mere continuation of the latter. They are se- parated from each other by the fourth ventricle and are inserted into the posterior upper part of the Pons , Varolii. In their centre is a denticulated oval ring of cineritious matter called Corpus Dentatum or Rhom- boideum. 64 OF THE HEAD AND NECK. The crura Cerebri arise from the medulla of all the lobes, make their first appearance at the back of the anterior, and between the middle lobes; their internal margins touch; they pass backward to be connected with the anterior superior part of the pons varolii and are lost in its substance. They are formed of a mix- ture of medullary and cineritious matter. The Pons Varolii, thus constituted by the blending of the substance of the four crura, two from the cere- brum and two from the cerebellum, is fixed upon the posterior part of the body of the sphenoid bone and on the cuneiform process of the os occipitis. It is between the anterior part of the cerebellum and the posterior part of the middle lobes of the cere- brum. It is hemispherical on its inferior surface, and about sixteen lines in diameter; is divided into two halves by a superficial middle longitudinal depression with transverse ridges passing from it on each side. In its substance is much cortical matter blended with medul- lary, the latter is arranged into striae running in differ- ent directions. The Medulla Oblongata is that portion of ence- phalic substance between the Pons and the superior 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 BRAIN AND SPINAL MARROW. 65 circular indentation above defining its boundaries at the Pons, but below there is none. A longitudinal fis- sure on its fore part, divides it equally. On each side of this fissure above, is an oblong eminence called Corpus Pyramidale, coming to a point below, and dis- appearing gradually. On the outer side of that again, and separated from it by a fissure on the side of the medulla oblongata, is an ovoidal and still more promi- nent convexity, but not so long, called Eminentia Olivaris. And on the outside of this is another and smaller eminence, the Corpus Pyramidale Laterale, or Corpus Restiforme. The Medulla Oblongata consists of medullary matter externally, and has some cineri- tious 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 Ventri- cle of the brain, which is closed below and separated from the spinal 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 cerebellum, 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 arrange- ment of its surface 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 contact 9 66 OF THE HEAD AND NECK. with each other; they are the Corpora Albicantia or Eminentiae Mamillares. They are placed in a cineri- tious substance, the Pons Tarini, or Tuber Cinereum, forming with them the floor of the third ventricle. The Infundibulum is a flat 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 generally impervious at its apex. It is cineritious externally, which gives it a red cast, and medullary internally. The Glandula Pituitaria occupies the sella turcica, and is somewhat spherical, being about six or seven lines in diameter. Its structure is firm and .resisting, formed of a tough cineritious matter externally, and of a kind of medullary internally. It is almost con- cealed by a close reflection of dura mater over it. There are nine pairs of nerves going from the basis of the brain, and named numerically by beginning in front. The 1st Pair, the Olfactory (Nervi Olfactorii,) appropriated to the nose, arise by three strias from the corpora striata, and make their appearance on the BRAIN AND SPINAL MARROW. 67 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 perforate the cribriform plate of the cethmoid bone by numerous 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. The 2nd Pair, the Optic Nerves (Nervi Optici,) are of considerable magnitude, and differ somewhat in their texture from the other nerves in consequence of having a general investment of pia mater before it sur- rounds their particular fasciculi; and also from having more medullary matter in them. They arise from the posterior end of the thalami and from the testes, and make their appearance between the middle lobes and the crura cerebri. There is a very close intertexture of the nerves of the opposite sides just before the in- fundibulum, so that it is a question whether they de- cussate each other, or simply unite. Being the nerves of vision, they pass to the ball of the eye, through the foramina optica and are expanded into the retina. The 3rd Pair, (Motores Oculorum,) arise from the inner margins of the crura cerebri near the pons va- rolii by several filaments. They pass outwards and 68 OF THE HEAD AND NECK. penetrate the dura mater near the posterior clinoid process and traversing the upper part of the cavernous sinus they get into the orbits through the foramen sphenoidale. They are distributed to the muscles of the eye, except the obliquus superior and rectus externus, and contribute to the ophthalmic ganglion. The 4th Pair, (Trochleares.) Each arises by two filaments which quickly unite, from the valve of Vieus- sens just below the testes. 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 running in an in- vestment of dura mater through the cavernous sinus at the outer side of this nerve, it afterwards crosses it above, and getting into the orbit through the fora- men sphenoidale, is appropriated to the trochlearis muscle. The 5th Pair, (Trigemini,) are the largest of all. Each arises by three portions, the middle being largest, from the side of the tuber annulare just where it is blended with the crus cerebelli. Their fibres may be traced through the pons into the posterior column of the medulla oblongata and are collected into one cord, which passes into a canal of the dura mater, lying on the anterior part of the petrous bone. They are not connected to the canal except at its lowest part, where BRAIN AND SPINAL MARROW. 69 they receive a coat from it. The nerve is then ex- panded like a fan, into seventy or eighty filaments. At the lower end of the latter is a brownish substance, the ganglion of Gasser, formed principally upon the middle root of the Trigeminus. The nerve then passes off in three great divisions, named from their appro- priations; the Ophthalmic nerve which goes out of the cranium at the foramen sphenoidale of the orbit; the su- perior Maxillary, at the foramen rotundum; and the Inferior Maxillary, at the foramen ovale. The 6th Pair, (Motores Externi.) Each nerve arises from the commencement of the medulla oblon- gata in the base of the corpus pyramidale, its root being frequently overlapped by theypns. It passes forward through the dura mater, in a canal, of the cavernous sinus, on the inside of the fifth nerve, and lying between this nerve and the carotid artery, it detaches one'or more filaments to form the commencement of the sympathetic nerve, and which 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 sphenoidale and is appropriated to the rectus externus muscle of the eye. The 7th Pair, is composed of two nerves the Portio Mollis and the Portio Dura. The first arises from the posterior face of the medulla oblongata, at the calamus scriptorius and corpus restiforme, being sepa- 70 OF THE HEAD AND NECK. rated from its fellow of the opposite side by the slit of the calamus scriptorius. The second, or portio dura, arises from the superior part of the corpus restiforme behind near the pons. A third nerve which, at a little distance, joins the portio dura, and is a mere fibril of it called portio Media, arises near the latter. The seventh nerve, thus constituted of a hard and of a pulpy portion, dips into the meatus auditorius internus. The mollis goes to the ear and is spent upon the la- byrinth; the dura, passing along the aqueduct of Fal- lopius, gets out at the stylo-mastoid hole and goes to the face. The 8th Pair, consists of three portions having diffe- rent destinations: The Glosso-Pharyngeal; The Par Vagum or Pneumo-gastric; and the Spinal Accessory nerve of Willis. The two first arise near each other behind the Corpora Olivaria from the side of the Me- dulla Oblongata. The Glosso-Pharyngeal is before the other, and consists of one cord. The Par Vagum is composed of several fasciculi having a flattened ap- pearance, which afterwards unite together. The Spi- nal Accessory has a remarkable origin from the posterior fasciculus of the Medulla spinalis, occasionally as low down as the seventh cervical nerve. Its fibres successively form a round trunk, which passing up the spinal canal and then into the cavity of the cranium through the foramen magnum, is associated with the nerves just mentioned; it is assisted also by contribu- BRAIN AND SPINAL MARROW. 71 tions from the side of the Medulla Oblongata. The eighth pair passes out of the cranium at the posterior foramen lacerum, anterior to the internal jugular vein, and separated from it by a spine of bone as well as 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 ad- here 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 Spinal Accessory for the muscles and integuments of the neck. The 9th Pair, (Hypoglossi.) Each nerve arises from the side of the medulla oblongata in 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 con- dyloid foramen, and is distributed to the tongue. Of the Medulla Spinalis. This is in continuation with the medulla oblon- gata, and is contained in the vertebral canal. It passes down as far as the first or second vertebra of the loins; and there terminates in a conical point. It has the same number of membranes with the 72 OF THE HEAD AND NECK. Brain; to wit, the Dura Mater, Tunica Arachnoidea and Pia Mater. The Dura Mater resembles very much the same membrane of the brain except that it has more elasti- city. It does not adhere closely to the bone, but lies loosely enveloping the spinal marrow and nerves, until it touches the foramina through which the latter pass out. Between the spinal canal 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 of the canal. At the egress of the dura mater from the cranium just around the foramen magnum, it adheres very closely to it and also to the first cervical vertebra. The Pia Mater is in close union with the Medulla Spinalis, and is commonly found with its veins injected after the same way, with the pia mater of the brain; it is, however, not so vascular, it ends by a conical cord below which goes to the lower end of the sacrum with the dura mater. The Tunica Arachnoidea lies loosely between the dura and the pia mater, preserving a character of extreme tenuity and transparency; it may be elevated any where with a pair of forceps; continues down- wards to the end of the spinal cavity, and connects the fasciculi of nerves together. On each side of the spinal marrow running between the anterior and posterior fasciculi of nerves, is a nar- BRAIN AND SPINAL MARROW. 73 , row semitransparent band, called Ligamentum Denti- culatum, fixed beneath the tunica arachnoidea, and con- nected to the pia mater by its internal margin. It is first observed arising at the occipital foramen; it then descends, and as it passes between the anterior and pos- terior fasciculi of nerves, it detaches many little round tooth-like processes, fixed to the inner surface of the dura mater, and carrying the tunica arachnoidea along with them. From these processes it derives its name. The Medulla Spinalis from being a continuation of the medulla oblongata, like it consists of two kinds of matter, cineritious and medullary. The latter is placed externally. The medulla spinalis has anteriorly and posteriorly a fissure penetrating almost to its cen- tre and extended its whole length, which divides it into two equal parts. These halves are again divided each into an anterior and posterior column, by a lateral fissure which is not so deep or long as the other, but terminates in the thoracic portion of the canal, and is nearer the posterior than the anterior fissure. The posterior column is again divided into two. These several divisions of the spinal marrow being connected by the internal cineritious matter, when a horizontal cut is made, the latter puts on the appearance of a line with a crescent at each end. At the upper end of the medulla spinalis near the oblongata, a considerable part of the anterior portions or columns crosses from the side to which they belong to the opposite one, and in doing so they are interwoven. 10 74 OF THE HEAD AND NECK. In the bottom of the anterior fissure there is a com- missure of transverse fibres, said to be like the teeth of a saw; and at the bottom of the posterior fissure there is a commissure of longitudinal fibres. From the anterior and posterior portions of the spinal marrow flat fasciculi of nerves proceed by double roots which penetrate the dura mater separately and derive a coat from it. This coat exists for some dis- tance as a sheath, united to the nerve by loose cellular substance, but is closely fixed to it near the interverte- bral foramen. The posterior fasciculus, at this place, forms a ganglion, which sends out a nerve at its fore part; this nerve, just at its origin, is united to the an- terior fasciculus, and thus forms the commencement of the spinal nerve. As soon as the spinal nerve clears the foramen between the bones, it sends branches backwards to the musoles of the spine, others forwards to join the sympathetic, and the middle trunk goes ac- cording to the part of the body to be supplied. There are thirty pairs of spinal nerves; seven to the neck, twelve to the back, five to the loins, five to the sacrum, and one which passes between the occiput and first vertebra called Sub-occipital. The nerves of the neck, from their origin to the intervertebral holes, are short and nearly horizontal; those of the back pass ob- liquely downwards, increasing in obliquity as they de- scend. 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, while still within the dura mater, the Cauda Equina. BRAIN AND SPINAL MARROW. 75 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 tempo- ral bones, 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, the Arteria Communicans Posterior, a branch which goes backwards, to join the posterior artery of the cere- brum; 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 sup- plies the anterior lobe of the brain and the corpus callosum. The arteria anterior communicates by a a short transverse branch, the Communicans Anterior, with its fellow. The Vertebral Arteries come up through the fora- men magnum and unite with each other at the poste- rior part of the pons varolii, to form the basilar artery. The Basilar artery divides anteriorly into two branches which run to the posterior lobes of the brain; they constitute the Arterias Posteriores Cerebri. From the basilar near the vertebrals, arises, on each side, a OF THE HEAD AND NECK. trunk, the Arteria Inferior Cerebelli; and from its an- terior part the Arteria Superior Cerebelli. The cir- cle of Willis is formed by the anterior bifurcation of the basilar, with the internal- carotids and the Arterias 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, lumbar and sacral arteries. The veins accompany the arteries and form 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. SECTION II'. Of the Anatomy of the Brain and Spinal Marrow, ac- cording to the system of MM. Gall and Spurzheim. The brain, and spinal marrow, as stated, consist of two kinds of substance, cineritious and fibrous or medul- lary. The cineritious is found abundantly on the surface of the brain, within its substance at particular places, and diffused through the spinal marrow; its consist- BRAIN AND SPINAL MARROW. 77 ence is pulpy and gelatinous, varying in degree in dif- ferent subjects. It is of a yellowish-red colour for the most part; and 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, according to Gall and Spurz- heim, is the matrix or soil of the fibrous substance con- stituting 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 con- sists 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 macerating them in nitric or muriatic acid diluted with alcohol. For these reasons Messrs. Gall and Spurzheim reject the term Medullary as communicating a false idea, and call it the Nervous Mass. The Spinal Marrow, according to these gentlemen, in worms and caterpillars, consists of a series of gang- lions 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 seg- 78 OF THE HEAD AND NECK. ment of these animals, there is one of these knots or ganglia for the origin of nerves, and the size and number of the nerves 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 prevails, only in not so distinct a shape, the ganglia being nearer to each other, and with the uniting bands forming a chord of more equal size, swollen however 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, detaching the tunica arachnoidea, and ob- serving the profile between the eye and the light. The outline is every where more or less waving, corres- ponding 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 en- larged from the third vertebra of the neck to the first dorsal; it is then gradually diminished to the tenth dorsal; it afterwards enlarges to the first lumbar vertebra, and forms an elongated point where it ter- minates. 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 symme- trical halves called Hemispheres. Besides which there BRAIN AND SPINAL MARROW. 79 exist the Pons Varolii and the Medulla Oblongata, till lately considered as emanations from the Cerebrum and the Cerebellum. On each side of the Medulla Oblongata there are three protuberances; the most anterior is the Corpus Pyramidale, just behind it is the Eminentia Olivaris, and behind it again is the Corpus Restiforme; these projections 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 those fasciculi instead of the latter coming from the cerebral mass, as is most commonly taught and be- lieved. The corpora pyramidalia, like the other emi- nences, are fibrous, and their fibres arise in a peculiar manner. This peculiarity consists in the fibres of the right corpus pyramidale arising from the left side of the medulla spinalis and the fibres of the left corpus pyramidale arising from the right side of the medulla spinalis. These fibres decussate each other an inch and a quarter below the pons Varolii, sometimes in single batfds, but commonly by an intertexture of three, four, or five fasciculi from each side. This arrange- ment 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. 80 OF THE HEAD AND NECK. This peculiarity in the origin of the pyramids is sup- posed to explain the fact of blows on one side of the head paralysing the opposite side of the body, as the same fibres are continued from the origin of the pyra- mids 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 crossing; are continued into the cerebral mass above and communicate with the medulla spinalis below. The principal facts worthy of notice being that a portion of the anterior columns retreat to form the bottom of the fourth ventricle, and that of the posterior column one part terminates in the borders of the same ventricle while the remainder is continued as corpus restiforme into the fundamental portion of the cerebellum. The Cerebellum. The Cerebellum consists of two lobes or hemi- spheres separated below in part by a groove wrhich makes them very distinguishable from each other. By opening this groove behind we get a view of the other or third part of the cerebellum, called Vermis Inferior, or, by Gall and Spurzheim, 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 cerebellum, BRAIN AND SPINAL MARROW. 81 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 per- fect; nevertheless, a constant uniformity is observed in all animals in regard to the origin from the medulla oblongata. In the interior of the medulla oblongata on each side, within the corpus restiforme, an accumu- lation 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 it 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 im- possible to pursue them in any determinate course. The corpus dentatum is considered as a ganglion or accumulation of cineritious substance, for the purpose of giving origin to more fibres in the cerebellum. Ac- cordingly 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 ramification of fibres departs from it, the quantity of cineritious substance about its root is increased, 11 82 OF THE HEAD AND NECK. hence results the fringed or serrated margin. That the corpus dentatum, is a matrix for the fibrous struc- ture 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. The Corpus Dentatum detaches inwardly a large branch which contributes to form the vermis or the Fundamental Portion of the Cerebellum. In the ver- mis, the fibrous or medullary matter radiates by seven branches towards its circumference, their extremities and subdivisions being covered by cineritious matter. The corpus dentatum also sends off other branches which go upwards, downwards, and outwards, towards the periphery of the hemisphere; expand into horizon- tal layers, and have their peripheral extremities cover- ed 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 dentajum; eleven principal branches are found proceeding from it; but this num- ber diminishes if the cut be made near the circumfer- ence of the cerebellum. It is this arborescent arrange- ment which, resembling the Thuya, or tree of Life, gives occasion to the name Arbor Vitas. BRAIN AND SPINAL MARROW. 83 " Horizontal or transverse cuts of these branches or leaves present only a white substance; therefore ana- tomists are wrong in maintaining that the quantity of the cineritious mass is more considerable in the cere- bellum 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 primitive 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 di- verging fibres; but always so as to converge towards the anterior external margin of the cerebellum, where they form a large and thick layer of fibrous matter. The anterior fibres cross in front of the tuber annulare, but the middle and posterior pass transversely through it, getting between the longitudinal bands of the tuber annulare which are distributed to the hemispheres of the cerebellum. These transverse fibres, from the op- posite sides of the cerebellum, unite with their con- geners, 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 MM. Gall 84 OF THE HEAD AND NECK. and Spurzheim, the Great Commissure of the Cere- bellum. Considerable light is thrown upon this subject by comparative anatomy, for this great commissure has its dimensions always in strict proportion to the de-, velopement of the lateral parts or hemispheres of the cerebellum. In the mammalia generally, as the lateral parts of the hemispheres are small, the tuber annulare is small. In fishes, and reptiles, it does not exist at all, because they have no hemispheres to the cerebel- lum. On the contrary, in man, the hemispheres of whose cerebellum are so large, the tuber annulare is remarkably broad and prominent: so much so as to con- ceal the origins of several nerves which are exposed in other animals, and, therefore, to assume fallaciously the appearance of giving origin to them. Although such animals as are destitute of hemi- spheres are without the great commissure of the cere- bellum, yet as they all have the fundamental portion, 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 fundamental portion, and join each other in constituting the Val- vula Cerebelli, or the Valve of Vieussens, which runs upwards and forwards to join the Inferior Tubercula Quadrigemina or the Testes. This primitive commis- BRAIN AND SPINAL MARROW. 85 sure of the cerebellum forms, in common description, the roof of the fourth ventricle. 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 con- tract 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 matter, some of the fibres deing disposed in layers and others interwoven with transverse chords coming from the cerebellum. Besides the filaments from the corpora pyramidalia, others arise from the posterior part of the medulla oblongata and from the corpora olivaria to penetrate into the pons varolii. The several fasciculi, thus formed from the different points of the medulla 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 cerebrum. And as in man, the infe- rior or pyramidal fasciculi receive the greatest acces- sion of new fibres; they, therefore form two thirds of these crura. In order to see the course just described of the 86 OF THE HEAD AND NECK. 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 the same side. With the handle of a scalpel intro- duced to the bottom of the incision, scrape or push the surface of the pons towards the crus of the cere- bellum 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 also called the great commissure of the cerebellum, and when all these are removed we 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 fibres 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 reinforce- ment of these fibres is produced by their meeting con- tinually in the Pons and the Crura Cerebri with cine- ritious substance. At the upper extremity of the crus where the optic nerve crosses it, the corpus striatum, a large mass of cineritious substance exists, and with which blend the fibres of the crus, whence an immense number of new fibres is generated and added to the course of the others. These fibres, shortly after their origin, begin to diverge, and being expanded in several BRAIN AND SPINAL MARROW. 87 directions terminate in the convolutions of the anterior and middle lobes of the brain; not in all of the convo- lutions belonging to these lobes, but in the inferior, anterior and exterior. In this way the original fibres of the corpora pyramidalia may be traced through the medulla oblongata, Pons Varolii, 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 those of the corpora pyramidalia through the tranverse 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 pyra- midalia. They form the interior and posterior part of the crura cerebri and pass through the thalami nervo- rum opticorum. The thalamus consisting principally of cineritious substance, through which the fasciculus of the corpus olivare has to pass, the fasciculus has an accession of many new fibres. MM. Gall and Spurz- heim reject the opinion of the optic nerve arising from the thalamus, and rather consider the thalamus as one of the ganglions of the brain, from its being appro- priated to the production of a great number of fine fibres, which ascend 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 penetrate the corpus striatum where it forms 88 OF THE HEAD AND NECK. a part of the lateral ventricle, and receive from it a considerable accession of new fibres. All the several fasciculi of the thalamus, by radiating very widely, are finally distributed in the convolutions of the posterior lobe of the brain, and in the superior convolutions of the anterior and the middle lobe. From the pyramidal fasciculi passing through the corpora striata and being there multiplied, and from the olivary fasciculi passing through the thalami and being there also multiplied, the corpora striata, and the thalami are said to be ganglions, or an appa- ratus of increase 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 orders of nervous fibres. The fibrillas 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 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 BRAIN AND SPINAL MARROW. 89 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. These fasciculi converge or incline towards the inte- rior of the brain in order to form with their congeners of the opposite side, a commissure between the two hemispheres. In some convolutions of the lower part of the posterior lobe, this converging mass may be followed 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 suscep- tible of distinct demonstration." " As these fibres converge, and as they have in every part a different course, and indeed in some places one altogether different from the diverging fibres, or such as come from the base of the brain, particularly 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 authorized to consider them as a particular nervous system." The Corpus Callosum, or Great Commissure, is, therefore, derived from the converging or returning fibres of the hemispheres of the cerebrum; the fibres from the opposite sides uniting at the raphe. The an- terior and posterior lobes are so disposed, that their 12 90 OF THE HEAD AND NECK. returning fibres do not cross transversely, but in a radiated manner; hence the great commissure is shorter than the hemispheres, as it occupies only their middle part. Also as these fibres are collected very much in consequence of their converging, the an- terior and posterior edges of the corpus callosum are thicker than its middle, and present the appearance of a fold not unlike that of the pectoralis major at the arm-pit. The Commissura Anterior is derived from the con- verging fibres of the front convolutions of the middle lobes. 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 convexity forward. The Commissura Posterior is derived from the pos- terior 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 ante- rior commissure. The Middle Commissure of the ce- rebrum is a mass of very soft and delicate 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. BRAIN AND SPINAL MARROW. 91 Several other parts of the cerebrum are considered as commissures by G. and S., or consisting of converg- ing fibres, as the Tasnia Striata, the Posterior Crura of the Fornix, and the Lyra or under surface of the Fornix. They, do not consider the obliquity of the course of the fibres of these bodies, an objection to their being commissures, inasmuch as the returning filaments of the middle parts of each hemisphere, are the only ones which have a transverse direction. The Septum Lucidum is also a commissure arising by a fasciculus of fibres sometimes strongly marked, from the most internal Convolution, at the anterior ex- tremity of the middle lobe, on each side. It ascends, in front of the anterior commissure, above the junction of the optic nerves, and is spread into a delicate mem- brane forming with its fellow the septum of the lateral ventricles. Between the two laminae composing 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 raphe by means of perpendicular fibres, the direction of which is diverg- ing 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 visible in many other places. For example, they exist in the transverse fibres at the bottom of the anterior fissure of the spinal marrow and of the medulla oblongata, in 92 OF THE HEAD AND NECK. the latter of which we must take care not to confound them with the decussation of the pyramids. And be- sides this, the longitudinal band at the bottom of the posterior fissure, extending the whole length of the spinal marrow, keeps its several nerves concatenated. The transverse band behind the commissure of the cerebellum in mammiferous animals, the junction of the tubercula quadrigemina and the transverse band at the origin of the fourth pai f 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 middle of the spinal marrow, demonstrates perpendicular 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 {Complicationes Transversa^,) which should be attended to. Messrs. G. and S. consider them as corresponding with the transverse bands at the joints of straw. They say that at every point of consider- able increase there is one of them, as at the lower end of the Corpus Olivare, in the middle of the Crus Cere- bri, at the external margin of the optic nerve in the Crus Cerebri, between the thalamus and Corpus Stri- BRAIN AND SPINAL MARROW. 93 atum, at the external margin of the Corpus Stri- atum. The Eminenti.e Mammillares are separated in the human subject, but adhere so as to form only one body in other mammalia. Each eminentia contains three, chords, two internal and one external. The ex- ternal unites with the transvevse band under the optic nerve in the crus cerebri. The foremost of the two internal chords unites with the anterior crus of the for- nix 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 Quadri gemina. " The Pituitary Gland is a collection of cineritious substance placed behind the junction of the optic nerves. It is obviously traversed by white filaments which arise in it, and is prolonged into the Infundi- bulum." 94 OF THE HEAD AND NECK. The Tubercula Quadrigemina. The anterior ones or the nates, are evidently ganglions for the origins of the optic nerves, (see the account of these nerves.) They are flattened^and somewhat cineritious externally and are united to each other by a strong and broad fasciculus, considered as a commissure of the optic nerves. The testes are of a more conical and ele- vated form, the medullary matter in them is more ex- ternal, 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 optic nerves. 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 terminating near the periphery of the brain, in the cineritious substance forming it. The other order of fibres is called converging, because they pass from the circum- ference of the brain to the interior parts or middle line, and constitute the Commissures. These con- verging fibres cross the diverging at various angles, sometimes obliquely, sometimes in a rectangular direc- tion. It is uncertain whence they proceed, whether they are derived from the imperceptible and curved extremities of the diverging fibres in the same way BRAIN AND SPINAL MARROW. 95 that the veins are continuations of the arteries, or whether they are a new creation in the cortical cir- cumference of the brain where they have their primi- tive radicles, 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 por- tion of the brain, as for instance the corpus callosum, 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 margins of the ventricles, they separate from each other and are prolonged into the convolutions, forming a fibrous ex- pansion. These fibres are not all of the same length, for soriie stop near the sides of the ventricles at the 96 OF THE HEAD AND NECK. bases of the convolutions, and others are extended to the surface of the brain. By such arrangement the convolutions are also of different depths. Each con- volution consists of two layers of the diverging fibrous or medullary matter, which are symmetrical, are in juxtaposition, and adhere to each other by their con- tiguous surfaces. Besides this, as has been several times stated, each convolution has its covering of ci- neritious matter, about a line deep. The medullary fibres penetrate somewhat into the internal face of this covering, from which it is paler and more firm than the exterior surface. The fibrous matter being suc- cessively inserted into the sides of the cortical cover- ing of the convolutions, its quantity of course is di- minished 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 centre 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 matter, has, in its structure, nervous fibres more minute and soft than the diverging ones. These are the com- mencements of the converging fibres, and can be seen only in the convolutions of the posterior lobes of the BRAIN AND SPINAL MARROW. 97 brain; the inference, however, is made that they exist in all the convolutions. It is these fibres which accu- mulate 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 laminae. Yet it does consist of two laminae with their opposite faces in contact, and agglutinated in all probability to each other by a loose cellular tissue. This fact is proved by the effects of hydrocephalus, for here the water, acting constantly with a distending force, separates.the two laminae of fibrous matter and sometimes effaces the appearance of convolution, con- verting it into a membrane. The prolongations or convolutions of the cerebellum are formed after the same manner, 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 hydroce- phalus, Dr. Gall found the following condition of the brain. The cerebral mass was distended 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 perfectly 13 98 OF THE HEAD AND NECK. white, and, in a majority of places not only the nervous fibres were distinctly seen, but the blood-vessels which accompany them. The ventricles contained about four pints of clear and limpid water. The fibrous structure and the blood-vessels had no where been im- paired. 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 general. This observation led to a train of reflections which terminated in Dr. Gall separating, artificially, the two laminae of the convolu- tions 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 by the side of pons varolii into the inferior process of the lateral ventricle, along the course of the taenia hippocampi. By this means they may be carried into the body of the lateral ventricle, and by gently extending and se- parating them, the convolutions are easily unfolded into a membrane without destroying their fibres. Dur- ing this operation a slight resistance is felt at the cir- cumference of the ventricles, 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 lacerated, the remainder of the separation is effected without much difficulty. All the interior of the cerebral expansion, thus produced, BRAIN AND SPINAL MARROW. 99 resembles a case of hydrocephalus; the fibrous struc- ture being unimpaired, 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 increasing 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 mat- ter 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 cir- cumference of the ventricles, and consequently nearer the surface than the intertexture which unites the di- verging 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 convo- lutions asunder, a very slight additional effort will be sufficient to separate them and to show that their lam- 100 OF THE HEAD AND NECK. inas are only agglutinated to each other. While this process is going on, a little groove or fissure is seen at the place of separation, as well as the perpendicular direction of the fibres and of the blood-vessels. Let the 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 authors 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 slightly adherent the one to the other. By blowing with a small tube transversely 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 supposed to exist, the convolution splits from top to bottom. By trying the same experiment on a convolution somewhat depressed at its summit, it opens at the base by a simple fissure, and at the superior part this fissure is extended towards each angle by being bifurcated. By injecting water in the direction of a fissure through a BRAIN AND SPINAL MARROW. 101 finely pointed syringe, the separation of the convolu- tions is made with still greater facility 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 communicating with this one: of which the examiner may be assured by cutting off the tops of such convolutions. This last experiment will suc- ceed 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 convolution. * Under the conclusiveness of such demonstrations the authors of the system very justly complain, that in- stead of considering the convolutions both of the Cere- brum and Cerebellum as consisting of two laminas of fibrous matter placed one against the other and cover- ed by cineritious substance, anatomists still continue to talk of a substance in the convolutions, which is white, soft, and pulpy. Of the Nerves of the Head. The most of them can be traced very satisfactorily to the medulla oblongata, and therefore they are con- * In all these experiments on the convolutions, it is better to have the pia mater removed previously. OF THE HEAD AND NECK. sidered from below upwards. Gall breaks up the association forming the 8th pair, and describes each as a distinct nerve. The Accessory Nerve forms a natural communica- tion 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 different individuals, and in the two sides of the same individual, sometimes be- ginning at the fifth, and sometimes at the seventh cer- vical 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- ness 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 spinal nerves, separately. These threads unite and form three or four fasciculi, which join successively into a BRAIN AND SPINAL MARROW. 103 common chord. The hypoglossal nerve is distributed to the tongue and to all the muscles attached to the os hyoides and to the salivary glands. It is connected also by anastomosis to nearly all the nerves found in the neck and throat. 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 injuries of the cervical medulla. The Par Vagum, or Nerve of Voice, arises by nu- merous 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 tickling of the pharynx; the connexion between the speech and the voice, &c; and the. oppression and cough from sordes in the stomach. The Glosso-Pharyngeal Nerve, composed of several filaments, arises from the medulla oblongata near the tuber annulare, and just above the par vagum. 104 OF THE HEAD AND NECK. It is united by ramifications in the neck to the facial and sympathetic; and is spent upon the constrictors 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 rise in the cineritious substance placed interiorly 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 produced by cineritious substance, and of uniting in the cere- bral 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, [n man it sometimes appears to come from the pons or medulla oblongata, or from between the two, according to the breadth of the former. But arising, in fact, from the lower part of the medulla ob- longata, it ascends the whole length of the pyramids at their side in the form of a little fasciculus, and di- vides commonly behind the pons into two smaller fasciculi which depart from the common mass of the medulla, one behind the other. The pons varolii be- ing much larger in man than in the animals just men- tioned, frequently some of its transverse fibres cover the motor externus at its point of departure. In this case it appears to rise from the pons, and as its fila- BRAIN AND SPINAL MARROW. 105 ments do not 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 oblongata and crus cerebelli, but its origin is better illustrated in the sheep than in the human subject, in the former of which it departs from the medulla below the posterior edge of the pons. It ascends as a fasciculus in the medulla oblongata between the corpus restiforme and the glosso-pharyngeal nerve, to a transverse band at the back edge of the pons in these animals. Passing below this band it pierces it at the internal 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 laugh- ing or in crying, and the pains in the head and ears during the toothach. The Auditory Nerve. On the anterior face of 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 individuals, being arranged sometimes in rays, occasionally as pencils, at other times they are parallel. Often those of one side are higher than those of the other; some- times they form little bands and then again are 14 106 OF THE HEAD AND NECK. rounded and projecting, being, in all cases, separated from each other by a fissure in the median line. Gall says he has never seen their decussation from the op- posite 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 strias; 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 cineri- tious substance is in less quantity in man, but forms an oblong elevation, the Fasciola Cinerea, called Ruban Gris by the French anatomists; in the sheep, hog, horse, ox, it is the size of a pea. This body may be considered the ganglion 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 auditory nerve. In animals, immediately behind the pons a large 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. BRAIN AND SPINAL MARROW. 107 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 separa- ted from the common mass. In mammiferous animals 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 poste- rior part of the pons till the fasciculus of this nerve be reached, it will then be easy to follow its entire 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." The Trochlearis, 4th Pair, arises from the side of the valve of the brain, but much lower down than is generally supposed, sometimes by one filament, 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. 108 OF THE HEAD AND NECK. The Motor Oculi, 3d Pair, issues from the in- ternal edge of the crura of the brain between the pons and the eminentias mammillares. Its origin penetrates to the third ventricle, but is separated from it by an interposed stratum of medullary matter. Many fila- ments compose its roots which are reinforced by addi- tions from the cineritious substance called Pons Tarini, but it has no filament from the eminentias mammilla- res as has been asserted. The Optic Nerve, in man, but more distinctly in mammiferous animals, 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 consider- able mass of cineritious substance, called Corpus Geni- culatum Externum, and is by it reinforced. So far the fasciculus is attached to the optic thalamus, but after- ' wards is only placed upon the crus 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 to a firm bed of cineritious substance, the tuber cinereum, and re- ceives from it, particularly above, several nervous fila- ments which unite to each of its sides. The optic nerve is so much reinforced by these filaments that the increase of its bulk is very perceptible, 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 BRAIN AND SPINAL MARROW. 109 have the same origin in man and in the mammalia. In the left hemisphere of the brain of a deranged female, 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 re- mained 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 attended with a corresponding diminution of the nates 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 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 distance by cineritious substance. These filaments approach each other and form commonly three principal roots, the internal of which is shorter and broader than the two external. The most exterior, which is the longest, 110 OF THE HEAD AND NECK. may be followed to the bottom of the fissura 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 hemispheres. 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 removed, immediately beneath it are the two Tarsi Cartilages, which form the margin and a considerable part of the breadth of the upper and of the lower eyelid. The upper cartilage is of a semi-oval figure, the broadest part being not quite half an inch; the lower cartilage is of an uniform breadth, not exceeding in any part one- fourth of an inch. Their external extremities are united with each other and kept in their places by a ligamentous expansion {Ligamentum palpebrale ex- ternum) connecting them.with the orbitar margin of the malar bone, and internally they are fixed to the nasal process of the superior maxillary bone by the THE EYE. Ill tendon {Ligamentum palpebrale internum) which affords origin in part to the orbicularis palpebrarum. The edge of these bodies is 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 car- tilage itself, is to be found in the centre of a small eminence, a foramen the Punctum Lachrymale, capable of receiving a bristle, and being the orifice of a canal, the Ductus or Canaliculus Lachrymalis, which conveys the tears into the Sacculus Lachrymalis. On the posterior surface of the tarsi cartilages, are placed several white tortuous canals in contact with each other, and having their extremities on the edges of the eyelids; they are the glands of Meibomius, and secrete an unctuous substance. In the upper lid there 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 infe- rior in size to a grain of wheat, and of a glandular structure for secreting an unctuous fluid. The lids are connected to the ball of the eye by a delicate vascular, and highly sensible membrane, the Tunica Conjunctiva, which is spread over the anterior third of the eye, not excepting the cornea, but there it becomes perfectly transparent. At the inner surface of the eye, the conjunctiva is thrown into a fold, the 112 OF THE HEAD AND NECK. Valvula Semilunaris, corresponding with the membrana nictitans of some animals. The Lachrymal Ducts (Canaliculi Lachrymales) are under the skin of the internal canthus, are from five to six lines long, and terminate by separate foramina in the sacculus lachrymalis. There is a sort of flap of the internal membrane of the sac which falls over these orifices. The Lachrymal Sac occupies all 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-quill at its nasal extremity, and there has the name of Duc- tus ad Nasum. A duplicature of the membrane of the nose resembling a valve, is frequently found at the orifice below. The Lachrymal Gland for the secretion of tears is placed in the superior and external part of the orbit, near its margin; it is about ten twelfths 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 exter- THE EYE. 113 nal junction of the tarsi cartilages. It is divided into an anterior and posterior lobe by a small ligamentous band attaching it to the depression of the os frontis. The muscles in the orbit are as follow: 1. Levator Palpebr^e Superioris arises near the superior margin of the optic foramen, and is inserted into the upper margin of the superior cartilage of the eyelid. Use, to draw the lid upwards. 2. Levator Oculi, or Rectus Superior, arises from the superior margin of the optic foramen, and is in- serted 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, or Rectus Inferior, arises from the inferior margin 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, or Rectus Internus, arises from the internal margin of the optic foramen, and is in- serted into the internal part of the ball of the eye near the cornea. It draws the cornea inwards. 5. Abductor Oculi, or Rectus Externus, arises from the external margin of the optic foramen, and is in- serted into the external part of the ball of the eye. It turns the cornea outwards. 15 114 OF THE HEAD AND NECK. 6. Oblmiuus 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 enclosed in a sheath sent off from the trochlea, its round tendon is inserted about half-way between the cornea and optic nerve in the superior part of the eyeball. It turns the eye on its axis. 7. Obliqjjus Inferior, arises from the orbitar plate of the superior maxillary bone near the os unguis, and is inserted into the outer part of the eyeball half-way between the cornea and optic nerve. It turns the eye on its axis. 8. Tensor Tarsi. At the internal canthus of the orbit is a small muscle belonging to the internal com- missure of the eyelids. 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 asthmoides, 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 lachrymale. To get a distinct view of it, the eyelids must be THE EYE. 115 separated from the eye and turned over the nose, leav- ing the tendinous attachment of the orbicularis and ciliaris muscle. The valvula semilunaris being brought into sight by this process, must be dissected away, and also the fat and cellular membrane underneath it. The muscle is now seen, and by passing bristles through the lachrymal ducts its connexion with them is render- ed 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 another fact of some im- portance, that the attachment of the inner commissure of the eyelids to the internal canthus of the orbit is imperfectly described, even by anatomists of much mi- nuteness in their accounts. It is attributed exclusively to the tendon of the orbicularis muscle, so much so that in the operation for fistula 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 ad- mitting the tendon of the orbicularis 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 116 OF THE HEAD AND NECK. curve commonly seen at their junction. The lachry- mal ducts are involved in this posterior ligament, pass- ing along it into the sac instead of going along the edges of the commissure, as commonly described, just under the skin. The muscle 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 lachrymal passages and for securing the course of the tears. I am indebted to Dr. Physick for a further suggestion in regard to its use, which appears highly probable. In cases of ex- treme emaciation, it is well known that the adipose matter around the ball of the eye is more or less ab- sorbed, causing the eye to sink deeper into the orbit, and consequently to retire somewhat from the lids. The effect of this muscle is to draw the lids backwards and to keep them applied on the ball. Again, in the elevation of the upper lid, or rather the drawing of it within the'orbit by the levator palpebras, the tendency of the margin of the lid is to leave the ball; the upper part of the little muscle 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. The puncta lachrymalia have a power noticed by Richter, of projecting themselves beyond the plane of he eyelid in which they lie, and have an equally obvi- THE EYE. 117 ous power of retracting themselves so as to do away all appearance of prominence. I do not understand the cause of the first motion, but the second 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 the 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, and muscles. Anatomists have devised various means for fixing it for dissection; for my own part I have found a common saucer sufficient, and water enough in it to float the organ; the specific gravity of this fluid approaches so nearly to that of the eye, that it affords a very good support to its delicate mem- branes, and sufficient stability for most purposes of ex- amination. The Tunica Sclerotica, the first coat of the eye, is to be examined by opening the ball very freely and turn- ing out all of its contents. We shall then see that it has considerable thickness, being of a compact fibrous texture, possessed of little elasticity, and therefore 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 connected behind, to the optic nerve, where it is perforated by several small 118 OF THE HEAD AND NECK. holes for the passage of the nerve; and before to the Cornea. The Cornea is a perfectly transparent membrane, consisting of many laminae united by a delicate cellular substance. It is much more convex than the sclero- tica, and is united to it by a broad sloping edge, where the two membranes adhere very firmly to each other by the sclerotica overlapping the cornea. They may be separated by putrefaction. The cornea in a healthy state has no red blood circulating through it. It is covered before by the tunica, conjunctiva, which there becomes assimilated in its sensible properties to it; and behind by the capsule of the aqueous humour. An eye being floated in the manner just mentioned, 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 circular cut should be made all around, taking great care not to injure the coat below. By making radiated sections to the optic nerve from this circular one, we shall be able to peel off, with but little difficulty, all the posterior part of the sclerotica; observing, however, to leave the optic nerve. What remains of the anterior part of the scle- rotica may be easily drawn away along with the cornea. This stage of the dissection gives a good view of the Tunica Choroidea; of a white circle called THE EYE. 115 the Ciliary Ligament seeming to terminate it before, 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 Choroidea lines all the interior of the sclerotica and is a much thinner and more delicate membrane than it; it appears black, and is covered on the outside with a flocculent cellular substance con- necting 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 choroidea 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 furnished 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 terminating in a fringe called Corpus Ciliare, and this fringe, if closely observed, will be seen to con- sist of a great number of short and distinct processes, arising from small folds called the Ciliary Striae, and covered with pigmentum nigrum. The Iris is a membrane placed across the eye just behind the cornea; it is highly vascular, but having a large quantity of pigmentum nigrum on its posterior 120 OF THE HEAD AND NECK. 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, and which is increased or diminished by the action of circular and radiated filaments composing the body of the membrane. They are considered by many as muscular. In the foetus the pupil is closed by the Membrana Pupillaris till the seventh month. The Ciliary Ligament as stated is a circle of whitish substance which is placed around the anterior part of the eye, and serves to connect strongly the Iris with the Tunica Choroidea; and these again with the an- terior edge of the Sclerotica and the margin of the cor- nea. 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 Choroidea. This is one of the nicest, manipula- tions in the whole dissection, and must therefore be done with great care. If it be well executed, the most delicate membrane in the human frame, will be found lining the choroid coat; it was discovered in Dub- lin, by Mr. Jacobs, and may be satisfactorily demon- strated, by commencing at the optic nerve with the ex- tremity of a knife-handle, and turning the membrane down, by scraping towards the anterior part of the eye. It extends from the optic nerve to the anterior edge of the Retina. THE EYE. 121 Beneath the Tunica Jacobi, is placed the Retina, a delicate, transparent, and pulpy membrane, extending from the optic nerve distinctly to the commencement of the Ciliary Striae of the Choroid Coat; and some anato- mists maintain that it goes on as far as the circumfer- ence of the Crystalline Humour, which is by no means so obvious. The optic nerve, after penetrating the cribriform 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 we commonly see them distended with blood in our dissections of ani- mals killed by a blow on the head. In the centre of the Retina is the foramen of Soemmering, surrounded by a yellow spot, and having a fold connecting it to the bulb of the optic nerve. Impressions made on the Retina are supposed, generally, to be the ca'ise of vision, and of the contractions and dilatations of the pupil. Dr. Physick believes, in regard to the latter, that the Iris is immediately stimulated by the light, as he has seen cases where the motions of it were active and well marked, in paralysis of the Retina. 16 122 OF THE HEAD AND NECK. 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 mem- brane or capsule, which is cellular; the peculiar con- sistence 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 Stris and Body. The Retina lies loo'se 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 three and a half or four lines in diameter, the posterior convexity of which is much the greatest. Its consistence is that of half dissolved glue, but it becomes more solid towards the centre. By putting it in boiling water for half an hour, it becomes hard and opake, and one is enabled to unravel its structure. It consists entirely of con- . centric lamellas, which, with a needle, may be separated into very fine fibres. It is enclosed in a capsule of the same shape, and between it and the capsule is found a small quantity of transparent fluid called Liquor Mor- gagni. Anatomists do not agree in regard to the THE EYE. 123 origin of the capsule, some thinking that it is entirely derived from the tunica hyaloidea, others that it is totally distinct from it, an opinion which I am disposed to consider the correct one. Admitting the opposite to be correct, the structure of the tunica hyaloidea is unquestionably much altered, especially in front, as the capsule there is possessed of more thickness, is elastic; and cuts very much like the thin shavings of a finger nail. In the tunica hyaloidea surrounding the circumference of the capsule of the lens, is placed the Canal of Petit, which, when inflated or injected is seen to be divided in a radiated manner by a number of incomplete 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 Ante- rior and Posterior Chambers of the Eye; all the space of the aqueous humour behind the Iris is called the Posterior Chamber, and all the space before the Iris is called Anterior Chamber. Both of these chambers are said by M. J. Cloquet to be lined by the capsule of the aqueous humour; this membrane, however, is not 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 124 OF THE HEAD AND NECK. 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 sphenoid Bone, detaches a large branch, the Ophthalmic; which in passing through the optic foramen is first under the optic nerve, then gets to the outside of it, and finally winds over to the inside of the nerve. Near the pos- terior part of the eye it sends off a branch which pene- trates to the centre of the optic nerve, and is distri- buted to the retina. It also divides into several branches which go to the Lachrymal gland;—to the muscles of the eyeball;—to the Tunica Choroides, con- stituting the Ciliary Arteries;—and finally, branches which pass through the anterior and posterior aethmoi- dal foramina and through the superciliary foramen. At the bottom of the orbit, and coming out at the infra- orbitar foramen upon the face, is found a large branch of the Internal Maxillary Artery. 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 THE EYE. 125 passing into the external jugular; and others, sending a trunk through the foramen opticum, which runs into the cavernous sinus, and consequently into the lateral sinuses. Five trunks of Nerves are to be found in the Orbit. 1st. The Optic, which is expanded into the Retina. 2d. The Third Pair, or Motor Oculi, which, pass- ing through the foramen sphenoidale 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 Palpebras Superioris; the other goes to the Adductor, the Depressor, and the Obliquus Inferior. From it is sent a filament which runs to the Lenticular or Ophthalmic ganglion; the latter is 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 fora- men sphenoidale. 4. The Motor Externus, or Sixth nerve, passes through the foramen sphenoidale of the orbit, and is spent on the Museums Abductor. 5. The first branch of the Fifth nerve, or the Oph- 126 OF THE HEAD AND NECK. i. thalmic, passing also through the same foramen, di- vides 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 at the Trochlea of the os frontis. The second passes along the inner side of the orbit, sends a filament to the Len- ticular ganglion; another through the anterior asthmoi- dal 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 Lachrymal 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. The External Ear consists of the structure exterior to the head; and of the passage called Meatus Audi- torius Externus, leading to the interior of the petrous portion of the temporal bone. THE EAR. 127 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 inside. The former being the part employed in collecting rays of sound and converging them through the meatus ex- ternus, merits our principal attention. The deep con- cavity in the middle of it, is called Concha. In the up- per part of the concha, and dividing it into two unequal fossas, we find a ridge of cartilage commencing, which is traced in the form of a scroll along the circumfer- ence of the pinna till it terminates insensibly in the posterior part of the lobus. This fold is the Helix; within it is a ridge of cartilage which is the Antihelix, terminating above by a bifurcation. On the anterior part of the concha, and overlapping it obliquely, is the cartilaginous process called Tragus, and opposite to it at the lower end of the antihelix is the Antitragus. Under the fold of the helix is the Cavitas Innominata, and between the bifurcation of the antihelix is the Scapha. The Meatus Auditorius Externus is about one inch in depth, calculating from the bottom of the concha; it proceeds obliquely forwards in a course correspond- ing to the situation of the petrous bone, and besides OF THE HEAD AND NECK. that, has a curve with the convexity upwards. The internal half is bony, but the outer half is composed 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 commencement of the helix with the tragus, is a ligamentous expansion which contributes also to the meatus externus. In the tragus cartilage, near the bone, are found two fissures filled up with elastic ligamentous substance; they are the Incisures. The whole of this arrangement of carti- laginous and membranous matter is highly favourable to the exercise of the sense, as the former, by its re- sistance, is well calculated for reverberating sound, and the latter affords great facility of motion as a kind of hinge is formed by the incisures. The cartilaginous is joined by ligaments to the bony meatus, the exterior edge of the petrous bone being rough and irregular for this purpose; there are also three ligaments, one sent to a point above 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 de- licate and sensible, is beset with hairs, and under it are found, in considerable numbers, the glandulae cerumi- nosae which secrete the wax. THE EAR. 129 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 He- licis Major; on its inferior part is the Helicis Minor; on the anterior side of the tragus is the Tragicus; on the anterior part of the antitragus is the Antitragicus; and on the cranial side of the ear is the Transversus Auris. In most persons there are also three muscles appro- priated to the movement of the external ear, upon the head, and which, though sufficiently well developed, are scarcely ever employed. The Attollens Auriculae, 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 Navicularis. The anterior Auri- culas, 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 Retrahens Auriculae, consisting of two or three slips, the inferior of which arises from near the root of the mastoid pro- cess, and is inserted into the prominence made by the concha below; while the second slip arises from the temporal bone higher up than the former, to be insert- ed alsointo the back of the concha above the first. The names of these muscles express their action. 2. The Tympanum is situated in the outer part of the Petrous Bone, and is separated from the Meatus Externus by a partition called Membrana Tympani. 17 130 OF THE HEAD AND NECK. The membrana tympani is placed very obliquely, just at the bottom of the meatus, its upper part being the outermost. It is not flat, but has its centre drawn in- wards by the handle of the malleus. It consists of four layers, the cuticle, the true skin, the proper mem- brane, and the lining membrane of the tympanum. When successfully injected, it shows a high degree of vascularity. The two outer layers are easily sepa- rated 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 vertical diameter rather more. On its superior posterior part is an oval opening communicating with an extensive 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 Naris. 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 in its apex. Four small bones are found in the tympanum, which THE EAR. 131 form a chain between the membrana tympani and the Labyrinth; they are the Malleus, Incus, Os Orbiculare? 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 of the anterior part of the neck, called Pro- cessus 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 Malleus. From the lower part of the body pro- ceeds the Processus Longus; and from the back part looking into the orifice of the mastoid cells is the Pro- cessus Brevis. The Os Orbiculare is a flattened sphere about the size of a mustard-seed placed between the extremity of the long process of the Incus and the Stapes. The Stapes resembles very much a stirrup-iron, and * This ligament is described by some as the Laxator Tympani Minor Muscle. 132 OF THE HEAD AND NECK. is placed horizontally at right angles with the malleus. It has a small head, articulating with the os orbiculare, 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 tympanum; 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 Eus- tachian tube from the pharynx, and into the Mastoid Cells. The little bones are all covered by a reflection 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 fissure of the temporal, and arising from the spinous process of the sphenoid bone, is inserted into the processus gracilis of the Malleus. It draws the Malleus out- wards, and consequently relaxes the membrane of the tympanum. THE EAR. 133 The Tensor Tympani arises from the cartilage of 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. 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 proceeded 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 hollow. The Semicircular Canals attached to the back and upper part of the vestibule, are so situated that one is Superior, another Posterior, and the third Exterior. 134 OF THE HEAD AND NECK. The superior and posterior are united together at their upper extremities, and therefore have a common 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 external extremity en- larged 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 depression, and be- low this and somewhat more internally is the hemi- spherical 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 vestibule is a foramen communicating with the cavity of the cochlea. The Cochlea, consists of a conical tube wound spirally two and a half times on itself, and is fixed at the anterior part of the vestibule. It has a broad cribriform base forming the bottom of the meatus audi- THE EAR. 135 torius internus, and an apex which occasions the pro- montory in the tympanum. Passing from its base torwards the apex is a pillar of Done called Modiolus, on which the conical tube is wound. This pillar tapers almost to a point, and then is spread out into a cavity resembling a funnel, from whence the name Infundibu- lum. The apex of the cochlea from its covering over the Infundibulum is called the Cupola. When the conical tube is cut open freely a partition 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, Coriacea, Vesicularis, and Membranacea. The lamina spiralis terminates in the infundibulum by a process called Hamulus. The divisions in the Cochlea thus made by the lamina spiralis form the scalas. The lowest of these scales 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 vestibule. From these communications we have the names Scala Tympani, and Scala Vestibuli. The scalae commu- 136 OF THE HEAD AND NECK. nicate also with each other just at the hamulus in the infundibulum. 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. Three Membranous Semicircular Canals within the bony, conforming to their figure' and containing a pellucid fluid; these canals all communicate by their extremities with a sac called Alveus Communis, situated in the semi-ellipitical depression of the vestibule.— Within the vestibule, and occupying the hemispherical cavity, is another and smaller sac like a bubble filled with a transparent fluid ; distinct from the former, and called the Sacculus Sphericus. To complete this part of the description of the labyrinth, it is to be observed that between the bony and membranous 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 connexion with this fluid that we find two supposed aqueducts for its removal, called after Cotun- nius, one for the Vestibule, another for the Cochlea. THE EAR. 137 The first arises near the common orifice of the supe- rior and posterior semicircular canals, and discharges itself just behind the meatus auditorius internus. The other comes from the cochlea near the foramen rotun- dum, 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 dis- tributed throughout the labyrinth. The bottom of the meatus internus being divided into two unequal fossae by a ridge; the uppermost is the smaller and perforated with several foramina, all of which, except the anterior large one are appropriated to the passage 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 fibrillas to the cochlea, vestibule, and semicircular canals. The portio mollis, descending to the bottom of the meatus, passes in several divisions, to the soft structure wifch- in the bony labyrinth. One division entering the vestibule, is spent on the alveus communis and mem- branous canals; another division goes to the sacculus sphericus. A third division, penetrating 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 * M. Ribes has ascertained that they only conduct blood-vessels. 18" 138 OF THE HEAD AND NECK. and other parts. The fibrillas of the portio mollis, during this distribution, continue exceedingly delicate, and are finally found in a pulpy state resembling the retina upon the internal surface of the cavities and sacs just mentioned. The Portio Dura, though not concerned in the function of hearing, passes through the petrous bone in a curious manner. Entering into the large foramen in the upper fossa of the meatus internus, it goes out- wards 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-mastoi- deum. It is afterwards distributed to the face. Its canal in the bone is called the aqueduct of Fallopius. Near the vidian foramen it sends a filament to the teisor tympani and at the "base of the pyramid one to the stapedius. 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, by going between the long leg of the incus and the handle of the THE NOSE. 139 malleus. It gets from the tympanum through a fora- men in the fissure of the glenoid cavity, and joins ulti- mately the lingual branch of the fifth pair of nerves. 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 ex- ternal ear are supplied from the stylo-mastoid and tem- poral 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 con- stituting its cavity, both individually and collectively. 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 sub- ject, which renders them two distinct cavities. This is effected by a cartilage placed at the anterior part of the vomer and of the nasal lamella of the aethmoid bone. At the junction of this cartilage with the nasal suture, it spreads out on each side into a wing, which is attached to the lower edge of the nasal bones, and the adjoining margin of the nasal process of the upper 140 OF THE HEAD AND NECK. maxillary, and extends, 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 membrane forming the side of the nostril. At the anterior part of this membrane is an oval cartilage which forms two- thirds of a ring, the exterior portion of it is the broad- est; the internal portion, placed in contact with the corresponding part of the oval cartilage of the other side, runs backwards, and forms by the union, the Columna Nasi. In the back of the ligamentous mem- brane there are several detached pieces of cartilage which give firmness to the structure and produce the prominence of the ala nasi. It is by means of these several cartilages that the orifice of the nostril is kept open. The posterior nares, being separated by the vomer, are oval, and do not present an outline differing much from that produced by the naked bone. At the poste- rior 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 to the cavity of the tympa- num. THE NOSE. 141 The Schneiderian membrane is spread over all the bones composing the nostril, and by its thickness dimi- nishes the foramina leading into the sinuses. Under the anterior part of the middle spongy bone is an orifice which leads through the asthmoidal cells into the fron- tal sinus. At the middle part of the middle meatus, or that between the lower and middle spongy bones, is the opening into the Antrum Highmorianum capable of giving entrance to a common quill. In the meatus formed posteriorly in the aethmoid bone, under the cor- net of Morgagni, are the orifices of the posterior asth- moidal 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 towards the cavity of the nose is villous like velvet, and is studded with many mucous follicles which pass obliquely into it, some of them being arranged in rows. It adheres closely to the bones, and that surface in the compact- ness 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, perfo- 142 OF THE HEAD AND NECK. rating the cribriform plate, and taking a coat of dura matter which renders them strong and fibrous. One row is spread on the membrane covering the upper part of the aethmoid bone, and descends as low as the inferior edge of the middle spongy bone; the other is distributed to the membrane of the nasal septum and its fibres descend somewhat lower. The fibrillae of these nerves terminate on the mucous surface of the membrane. 2. The Spheno-Palatine Nerve comes from the Spheno-Palatine Ganglion through the spheno-palatine 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 asthmoidal fora- men 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 asthmoidal branches of the ophthalmic. Its veins accompany the arteries. THE MOUTH. 143 SECTION VI. Mouth. The cavity of the mouth is chiefly formed by the palatine process of the upper maxillary and palate bones, above; by the tongue and the muscles connected with it, below; by the cheeks laterally; by the lips be- fore; 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 styloid 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. The lingualis, which arises indistinctly 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 contact with its fellow of the opposite side. It arises from the tubercle on the posterior face of the symphysis of the lower jaw; its 144 OF THE HEAD AND NECK. 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 organ in various directions and facili- tate much its motion. They are the superficialis linguae forming a thin layer on the upper surface of the tongue; the Transversales Linguas being scattered fasciculi going horizontally, and the Verticales Linguas which are also scattered and go vertically. The superior surface of the tongue on its anterior two thirds 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 backwards, 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 Papillae Capitatas or Maximas. Distributed over the tongue, and scattered at irregular distances from each other, are the Papillas 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 Pa- pillas Filiformes. It is probable that these Papillas, ex- cept the first, are essentially connected with the function of taste, as they are abundantly supplied with nerves and blood-vessels, having a peculiar ar- rangement. THE MOUTH. 145 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 within this duplicature is a liga- mentous bridle serving to keep the Epiglottis cartilage erect; muscular fibres from the base of the tongue form its commencement. On each side of it is a small pouch which occasionally produces some trouble from articles of food lodging in it. A little anterior to this fold is a small blind hole, receiving the central papilla maxima and into which some mucous glands discharge their contents, it is called the foramen Cascum of Morgagni; and sometimes behind it is another foramen cascum but without a papilla. Scattered about the root of the tongue we find many mucous glands. The lining membrane of the mouth, when the cuti- cle is separated from it by maceration, exhibits a sur- face covered with fine vilii. On the lips and cheeks, under it, are situated many small glandular bodies, called Glandulas Labiales, and Buccales. It forms a frasnum 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 lower side of the tongue by a frasnum, 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 19 146 OF THE HEAD AND NECK. twenty distinct orifices. On the cheeks, opposite the interstice of the second and third molar teeth of the upper jaw, is found the orifice of the duct of the Parotid 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, trans- verse ridges extending towards the alveolar processes. It adheres very closely to the bone, and beneath 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 depressing the lower jaw, an incomplete partition which divides it from the pharynx. It is the Velum Pendulum Palati, formed by the lining mem- brane of the mouth reflected over several muscles. In the centre is a projection termed Uvula. On each side of the uvula the soft palate has its inferior margin ter- minating in two crescentic ridges called 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 inserted into the side of the basis of the tongue. The posterior half arch, arising from the side of the uvula near the anterior, runs back- THE MOUTH. 147 wards 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 ulceration. The .space between the lateral half arches is the Fauces, and the anterior open- ing into it, is the Isthmus of the Fauces. By dissecting off the membrane of the soft palate 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 Constrictor Isthmi Faucium, which arises from the middle of the soft palate near the root of the uvula, and is inserted into the side of the tongue near its root in a line with the papillas maximas. 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 constric- tors and into the superior posterior margin of the Thyroid Cartilage. It draws the velum palati down- wards. 3. Circumflexus or Tensor Palati, arises from the spinous process of the sphenoid bone behind the fora- 148 OF THE HEAD AND NECK. men ovale, and from the contiguous part of the Eus- tachian tube, it passes m contact with the pterygoideus internus muscle, and terminates in a broad tendon be- low, which winds around the hook of the internal 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. 4. 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. 5. The Azygos UvuLiE arises from the posterior ter- mination of the palate suture, runs through the centre of the soft palate, and ends in the point of the uvula. It draws the uvula upwards and diminishes the verti- cal breadth of the soft palate. SECTION VII. Of the Pharynx and (Esophagus. . The Pharynx is a large membranous cavity placed at the posterior part of the nose and of the mouth for PHARYNX AND OZSOPHAGUS. 149 opening an external communication with the cavities of the thorax and abdomen. It lies before the cervi- cal vertebras, being connected to them by cellular mem- brane, is closely attached to the basis of the skull be- fore the foramen magnum, to the posterior margin of the upper and under jaws, to the back parts of the os hyoides and of the thyroid and cricoid cartilage, and below it contracts so as to be continuous with the oesophagus. In consequence of these several attach- ments 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 continuous with the lining membrane of these several cavities. 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 be 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 pairs. 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 150 OF THE HEAD AND NECK. muscle, and its inferior fibres are more transverse, 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 cunei- form process of the os occipitis just before the foramen magnum. 3. Constrictor Pharyngis Superior, arises 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. It is in- serted into its fellow by a white line in the middle of the pharynx and the upper end of which adheres to the cuneiform process of the os occipitis; it has its lower edge concealed by the preceding. 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. PHARYNX AND OZSOPHAGUS. 151 The (Esophagus. 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 vertebras, penetrates through the left foramen of the diaphragm and terminates in the cardiac orifice 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 below than above. The muscular coat is very strong, consisting of two planes of fibres, the external being longitudinal and the in- ternal circular. The nervous coat connects together the other two; it is formed of 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 cuticle, 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 distension; it abounds with mucous follicles, and is well furnished with blood- vessels. 152 OF THE HEAD AND NECK. SECTION VIII. Of the Larynx. By the term Larynx is understood the irregular cartilaginous tube which forms the upper termination of the windpipe. The basis of the structure is made by 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 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 receive the tip of the little finger. At the ends of the base the two cornua arise, separated from it by cartilage and there- fore moveable; they are about an inch long, are some- what flattened, and have a tuberculated termination 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 obliquely towards THE LARYNX. 153 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 Arytenoid, and the Epiglottis. The Thyroid Cartilage, (Cartilago Thyroidea,) is about an inch below the os hyoides, and forms a very striking prominence in the male neck. It consists of 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 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 pro- cess on each side, the Cornu Majus, which looks to- wards the end of the cornu of the os hyoides and is connected to it by a round cord the posterior thyro- hyoid ligament. The inferior edge is somewhat in- curvated, and terminates behind by a short process on each side, the inferior cornu, or Cornu Minus, by which it is fastened by the posterior crico-thyroid ligament to the side of the cricoid cartilage 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- 20 154 OF THE HEAD AND NECK. 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 cartilage. The interior surface is flat, the exterior is marked by the muscles which lie on it. The Arytenoid Cartilages, (Cart. Arytaenoideae, Triquetras,) two in number, one on each side of the upper back part of the cricoid, resemble each a trian- gular pyramid curved backwards and having an ex- cavated base. The internal sides of the two are flat, face each other, and by the action of their muscles may be brought together; when thus joined they re- semble the spout of a pitcher. In front they are ex- cavated somewhat irregularly. On the top of each is a little cartilaginous 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 aryte- noid 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 THE LARYNX. 155 of the os hyoides and has its pedicle connected to the entering angle on the posterior face of the thyroid car- tilage. The broad surfaces of this cartilage 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. It is very elastic, having a fibro- cartilaginous structure, and is perforated with many foramina giving it a cribriform appearance. The upper edge of the Thyroid Cartilage is connect- ed to the internal edge of the Os Hyoides, by a thin and somewhat elastic membrane the middle thyro-hyoid ligament, which fills up 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 Hyoides, is a small sac, very rarely men- tioned by anatomists, and considered by such as speak of it, as a Bursa Mucosa. It has no connexion with any other cavity, and is occasionally the seat of dis- ease. Between the Epiglottis and the Thyroid Cartilage, and on the posterior face of the Thyro-hyoid liga- ment, 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 156 OF THE HEAD AND NECK. front, there is a ligamentous membrane which fills up this interval; it is the middle Crico-thyroid ligament, and in Laryngotomy, is indicated as the proper place for the operation. From the anterior part of the base of each Aryte- noid cartilage, a ligament passes horizontally to the entering angle of the Thyroid. These ligaments are not parallel, but converge from the Arytenoid cartilages, and are very near each other in front. At the distance of three lines above these, are two other ligaments passing also horizontally from the Arytenoids to the thyroid cartilage; they are more parallel, but have riot 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, which is described in the account of the neck. 3. The Crico-Arytenoideus Posticus, arises from THE LARYNX. 157 the back of the cricoid cartilage, occupying its excavation, and is inserted into the posterior part of the base of the arytenoid cartilage. Use, 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 pos- terior face of the thyroid cartilage, and the ligament connecting it with the cricoid, and is inserted into the anterior edge of the arytenoid cartilage. Use, to re- lax 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 some- times only one muscle exists. Use, to close the chink of the glottis. 7. The' Arytenoideus Transversus, arises poste- riorly 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. 158 OF THE HEAD AND NECK. 8. The Thyreo-Epiglottideus, arises by a few fibres, from the posterior face of the thyroid cartilage 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 downwards. These two last muscles are frequently so small and undefined, that they cannot be satisfactorily dis- tinguished from the adjacent soft parts. • The cavity of the Larynx is lined by a continuation of the mucous membrane of the Pharynx. This mem- brane, where it establishes the upper boundary of the Laryngeal cavity, forms a fold on each side, extending from the Epiglottis to the Arytenoid Cartilage; it then sinks into the cavity beneath. In extending 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 Glottidis; and the cavity above the upper liga- ments is the Glottis. For an account of the Trachea, see the article Thorax. 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. 1. The Pectoralis Major is the most superficial, and forms the large swelling cushion of flesh under the skin of the breast. It arises tendinous from the ante- rior face of the two upper bones of the sternum their 160 OF THE TRUNK. 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 the interior two-thirds of the clavicle. The clavicular and sternal portions of the origin are separated by an interval, giving the appear- ance of two muscles. The fibres converge and terminate by a broad, thin tendon, which is inserted into a roughness on the exte- rior edge of the fossa of the os humeri for the biceps tendon, and into the bracial fascia. The under edge of the muscle, near its insertion, is folded inwards, which gives the rounded thick margin to the fore part of the axilla. That part of the broad tendon belong- ing to the clavicular portion of the muscle is inserted lower down than the sternal, which produces a decus- sation 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 digita- tions from the upper edges of the third, fourth, and fifth ribs. It soon becomes fleshy, and is inserted, by a short flat tendon, into the inner face of the coracoid process of the scapula. Its use is to draw the scapula inwards and downwards. MUSCLES OF THE THORAX. 161 3. The Subclavius is a small muscle placed imme- diately under the clavicle. It arises from the cartilage of the first rib, and is inserted into the inferior face of the clavicle from near the sternum to the conoid liga- ment, which connects the coracoid process and the clavicle together. It draws the clavicle downwards. 4. The Serratus Major Anticus is a broad muscle 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 from the nine upper ribs by fleshy digitations, the superior one of which seems almost like a distinct muscle, the five lower are con- nected to the obliquus externus abdominis, the digita- tions of the two muscles interlocking with each other. The fibres converge, and are inserted into the base of the scapula its whole length. Its action is to draw the scapula forwards. 5. The, Intercostals fill up the spaces between the ribs. There are two in each space. The External 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 21 162 OF THE TRUNK. superior rounded edge of the rib below on its inner side, its fibres passing obliquely backwards. They draw the ribs together. With a view to examine the cavity of the thorax, the sternum along with the cartilages of the ribs, is to be taken out. We then see, on their posterior faces, a muscle called 6. 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 upwards and outwards to be inserted into the cartilages of the third, fourth, fifth and sixth ribs by fleshy and tendi- nous digitations. Its use is to depress the ribs, and consequently to diminish the cavity of the thorax. 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 Professor Wis- tar, in which the five middle true ribs on each side are removed, all the rest with the sternum being left. VISCERA OF THE THORAX. 163 This plan gives an excellent view of the several visce- ra, and also of their relative situation and extent; and 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, inasmuch as the superior ex- tremities must be removed in the first place. If the muscles connecting the upper extremities to the trunk, on its fore and back parts, should have been previously dissected, this objection 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 an appropriate membrane. The heart is between the sternum and the dorsal vertebras; the lungs are on each side of it and when in a healthy state, always collapse upon the thorax being opened. The Pleura,. Each of the two lungs has an 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 side of the pericardium to the sternum before, and to the spine behind. This membrane also 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 164 OF THE TRUNK. 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 Pleura 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 opposing faces of them form a septum, which extends from the ster- num in front to the spine behind, and from the upper part of the thorax to the diaphragm. This septum is the Mediastinum; and the heart is placed in its middle. The portion of the septum between the heart and ster- num is the Anterior Mediastinum; between the heart and spine is the Posterior Mediastinum; and between the heart and the upper part of the thorax, is the Supe- rior Mediastinum; each of which merits strict at- tention. It is obvious then, that the septum consists of two laminas, one from each pleura. These two laminas are somewhat separated, where they are called 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 longitu- dinally, 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. VISCERA OF THE THORAX. 165 The Pleura is a thin and transparent membrane con- nected to the parts on which it lies by a short cellular 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 Avith corpulency, considerable masses of fat are found in the anterior me- diastinum, and between it and the pericardium. The exhalent vessels of the pleura are derived from the inter- costal, internal mammary, phrenic, and some other ar- teries, and secrete a fluid which, lubricates its surface. The Pericardium. Between the pleuras, and under 'the sternum, is the Pericardium, containing the heart. It is a white, semi- transparent membrane, of a condensed fibrous struc- ture internally, and possessed of little or no elasticity, which renders it highly appropriate for sustaining the action of the heart in its dilatation. It is lined by a serous lamina which forms a com- plete bag in being reflected over the surface of the heart, so as to give it an investing membrane. This investment comnences at the back part or base of the heart, and is continued over the whole of it, being ex- tended 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; 166 OF THE TRUNK. and on the descending cava to the middle of the space between the entrance 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 arrangement with the membranes of the joints; the exterior lamina of the pericardium corresponds 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 furnishes the lubricating fluid, found in general in the pericardium, to the amount of a drachm. The fore part of the pericardium lies loosely on the heart. The pericardium is attached strongly, by all its inferior surface, to the tendon of the diaphragm. The Heart. The Heart is a hollow muscle consisting of four cav- ities, two auricles, and two ventricles. Its shape is somewhat conical, but flattened on the under surface. 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 sternum and the dorsal vertebrae, has its base turned obliquely towards the right side, while its apex is about the junc- VISCERA OF THE THORAX. 167 tion of the fifth left rib with its cartilage. Its flat part reposes on the flat tendon in the centre of the dia- phragm, also 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 it, others in an irregular and in- determinate manner, but all in such a direction as to concur, by contracting, in effacing its cavities. The cavities are lined by a fine membrane which is a con- tinuation of, and resembles the internal coat of the arteries and veins. Between the auricles and ventri- cles, and at the orifices of the great arteries, this membrane is raised up and reflected so as to constitute valves. The heart is divided into Right and Left sides, each consisting of an auricle and of a ventricle. The Right 168 OF THE TRUNK. Auricle receives the two great trunks of the Venous System, to wit, the ascending and the descending Vena Cava. The Left Auricle receives the pulmonary veins. The Right Ventricle sends off the Pulmonary 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 auricles. This last circumstance, connected with a slight thickening of the part, has given occasion to the name Tuberculum Loweri. An- teriorly the auricle is swelled into a pouch,. (Sinus Ve- nosus) in which the muscular fibres, instead of being uniformly spread into a coat, are collected into trans- verse fasciculi lying parallel to and near each other; they are called Musculi.Pectinati. At the upper part of the pouch or sinus is the proper auricular portion of the cavity, whence it got its name; it is not marked by any striking peculiarity except that the musculi pectinati prevail in it. The auricles have a common septum, and on it, just below the tuberculum Loweri, is situated the Fossa Ovalis, which in the foetal state was an opening between the auricles, and indeed at the upper part of this depression we often find a fora- VISCERA OF THE THORAX. 169 men large enough to admit a probe into the left auricle even in subjects advanced into old age. The edges of the fossa ovalis, are elevated and thickened, being the Columnas 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 side of the annulus ovalis; it terminates anteriorly about the junction of the auricle and the vein. It is con- nected by its convex edge to the parietes of the auri- cle, and its concave or floating edge looks somewhat upwards. Just before and below the Eustachian valve is another much smaller, but also semilunated, the Valve of Thebesius, which covers the orifice of the great coronary vein. At the left side 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 coro- nary veins called Foramina Thebesii; they also exist in all the other cavities, but are not so numerous there. They are said to be particularly conspicuous in cases of diseased lungs. The next cavity to be examined is the Right Ventri- 22 170 OF THE TRUNK. cle; to expose it satisfactorily it should be divided extensively along the septum ventriculorum superiorly 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 inter- nal surface is very irregular and rough, the muscular structure of it being thrown into projecting columns the Columnas Carneae of very indeterminate figures, arrangement and dimensions. Some of them jut out and are connected to the valve at the ostium venosum by the Chordas Tendineae; others pass from one side of the ventricle to the other, and a third series presents a reticulated appearance, lying on the face of the ven- tricle and connected with it. Their general object is to strengthen the ventricle, to enable it to expel its contents 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 divided at its floating edge, into three parts, whence the name of Tricuspid Valve has been given to it. The tricuspid valve, is situated in the ventricle, has its loose margin attached to the round tendinous chords just mentioned, called the Chordas Tendineae, which again arise from the Columnae Carneas. These tendinous attachments of the tricuspid valve prevent it from being thrown into the auricle when the ventricle contracts. At the upper part of the ventricle is the orifice of VISCERA OF THE THORAX. 171 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 beyond its orifice, three valves arise called Semilunar, which may be compared, each to a semicircular, plane, con- nected by its circumference, to a cylindrical cavity. The diameter of the plane is loose; in the centre of it, is a small cartilaginous body, the Corpusculum Au- rantii; and on each side of the corpusculum, the diam- eter of the valve, instead of being a straight line, is slightly festooned. The valve is almost diaphanous, and seems to be produced by a reflection of the lining membrane of the artery. Between 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 below 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 ventricle; and the Corpuscula Aurantii being in the middle of each form a point of support or abutment at which the edges of the valves sustain each other. Between the outer face of the valve and the internal face of the artery, a pocket attended with a dilatation of the artery is formed, called the Sinus of Valsalva. 172 OF THE TRUNK. 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, right and left, which go to the lungs of their respective sides. The right branch is the larger of the two, and passing under the arch, is then minutely distributed to its lung. The left is in front of the descending aorta, and is distributed to the left lung with equal mi- nuteness. 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 pene- trates the pericardium. This trunk afterwards unites to the auricle at one of its corners. The Left Auricle has about the same cubic capacity 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 posterior part of the left ventricle, and is divided like the right auricle, into the Sinus Venosus, sometimes called Sinus Pulmonalis, and into Proper Auricle. The latter is situated at the left side of the pulmonary artery, and is somewhat longer, narrower, more crooked, and more notched at its margins than the other proper auricle. When the left auricle is cut open, which should be done by a slit down its middle, it will be perceived that VISCERA OF THE THORAX. 173 its parietes are thicker than those of the right, and that both externally and internally, its surfaces are per- fectly 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 appear- ance; when held up to the light, it is seen to be thinner and more transparent at the place corresponding with the fossa ovalis of the other side. At the anterior and inferior side of the auricle is the ostium venosum, communicating with the left ventricle; it has a ten- dinous margin, and is rather more than an inch in diameter. The left Ventricle differs from the right in shape, by being more conical, but it is equally capacious. Its anterior part constitutes the apex of the heart, and strikes against the ribs. The best mode of examining its cavity is to make an incision through its parietes 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 parti- cular care, so as to avoid wounding the interior struc- ture. That done, we see its general arrangement .within, corresponding with the right ventricle. Its parietes are eight lines through, being about three times as thick as the other. Its columnae carneae 174 OF THE TRUNK. are larger and stronger, but arranged 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 aiding the valvular apparatus at the ostium venosum. 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 columnas car- neae are numerous and strong, and its chordas tendineae are of corresponding characters. The mitral valve prevents the regurgitation of blood into the auricle, 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 diame- ter, 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 ad- dition that those parts of the aorta are stronger and more developed. The coats of the aorta are nearly VISCERA OF THE THORAX. 175 three times as thick as those of,the pulmonary artery, to qualify it for bearing the increased pressure of the blood. The aorta is dilated shortly after its com- mencement so as 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 superior 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 be- sides the fluid circulating through its great cavities; this is furnished by the Coronary Arteries, which are two in number. The first, called Right Coronary, be- comes visible between the pulmonary artery and the right auricle, and passing on the septum between the right auricle aud ventricle, extends around the heart to its flat side, distributing to the contiguous parts branches which, for the most part, pass off at right angles. The second, or Left Coronary Artery appears between the pulmonary artery and the left auricle; before it has become very obvious, it divides into two branches, one passes on the septum ventriculorum to the apex of the heart; the other winds on the septum between the left auricle and the left ventricle, and 176 OF THE TRUNK. some of its branches pass on the flat surface 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 are of a bluish colour, and occupy by far the greater part of the cavity of the thorax ; they are two distinct bodies placed one at either side of the heart, from which circumstance they are called right and left Lung. Their external shape and dimensions with an inconsiderable exception, are the same, as they correspond in their periphery with the symme- trical sides of the thorax. The apex of the heart, from being pushed into the lung of the left side, gives its surface towards the mediastinum, a somewhat different figure from the lung of the right side; the left lung is also the smaller. To appreciate the extent and form of the lung, it must be recollected that the cavity of the thorax is much deeper behind than it is before. The vertical diameter before, amounts only to the length of the two upper bones of the sternum, whereas the same diame- VISCERA OF THE THORAX. 177 ter behind, is the whole length of the column formed by the dorsal vertebrae. The figure of each lung is also modified by the convexity of the Diaphragm; for this body, extending from the lower point of the dorsal ver- tebras obliquely upwards to the end of the second bone of the sternum, would, if it were only a plain surface, in- fluence 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 convexity 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 ana- tomical comparison, and particularly as it regards their inferior surface. 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 trachea. These tubes constitute the Root of the Lung, and over the root is reflected the pleura, from the pericar- dium. The pleura which covers the root of the lung is extended downwards, under the name of Ligamentum Pulmonis, and serves to fix the posterior edge of the lung to the pericardium, as low down as the dia- phragm. The right lung is divided by an oblique and a hori- zontal fissure passing from it, into three lobes—the 23 178 OF THE TRUNK. left lung has a single oblique fissure dividing it into two lobes. Each lobe consists of a multitude of lobules adhering laterally by cellular substance: and each Ipbule is formed of a congeries of air vesicles, which communicate freely through their sides from the im- perfection of the latter. Though the cells of different lobules do not communicate in that direct way. . The parietes of the air vesicles are of extreme tenuity and have the pulmonary artery and vein rami- fying with exceeding minuteness on them for the pur- pose of respiration. The lung of the bullock exhibits the structure better than that of the human lung, by a little tearing of the parts asunder. The lobuli are also well seen in the foetus, and in very young subjects. The Trachea, the bifurcation of which forms the Bronehias is a tube almost cylindrical, which passes in front of the oesophagus and of the vertebras, from the inferior part of the larynx to the third dorsal vertebra; it there divides into the Bronehias, and is placed be- tween the pleurae of the two sides of the thorax. The right Bronchia is shorter, larger, and less slanting than the left; it sinks below the pulmonary artery, and penetrates the lung opposite to the fourth dorsal ver- tebra ; the left being long and narrow, enters the lung below the pulmonary artery, opposite to the fifth dorsal vertebra. The bronehias then divide and subdivide VISCERA OF THE THORAX. 179 through the structure of the lung, till the ultimate ex- tremities terminate in the air vesicles. The trachea preserves its cylindrical shape, and is kept open by a cartilaginous structure, which is com- posed of from sixteen to twenty pieces, more or less distinct from each other. Thus arranged, the carti- lages, form about two thirds of the circumference of a circle, occupying the front of the trachea, and giving it the appearance, anteriorly, of a cartilaginous tube. The remaining third is membranous. The cartilages of the trachea are deposited in a kind of perichondrium, possessed of extreme elasticity, which has continually a tendency to approximate the cartilages, and is re- sisted only by the attachments of the two extremities of the trachea. The effect of this elasticity is demon- strated 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 having been removed. The deficiency at the back part of the cartilages, is filled up by a condensed cel- lular substance in continuation with this elastic mem- brane. Transverse muscular fibres are placed between the extremities of the cartilages, and by their contrac- tions bring them towards each other; according to the opinion of Dr. Physick, by diminishing the size of the trachea they assist in the expulsion of mucus. A con- tinuation of the mucous membrane of the Pharynx and Larynx lines the trachea; it is studded with a great number of follicles which secrete mucus. Under the 180 OF THE TRUNK. membrane are many glands, from the size of a millet- seed to that of the head of a small pin and which have their excretory tubes terminating in the trachea. These glands are also abundant on the posterior face of the transverse muscular fibres. The Bronehias, in dividing, still preserve, for some length, the cartilaginous structure of the trachea, but as they approach their terminations, 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 car- tilages are deposited, forms the essential cellular structure of this organ on which the blood vessels are ramified. At the lower end of the trachea, and about the root of the lungs, is found the commencement of a chain of lymphatic glands which follow, for some distance, the bronchiae. In the adult they are black, numerous, and vary from the dimension of a large pin's head to that of a kidney bean. The lungs are furnished from the aorta with nutri- tious vessels, called Bronchial Arteries; they follow the course of the bronchiae and communicate freely with the pulmonary arteries; notwithstanding the latter they VISCERA OF THE THORAX. 181 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 communicate 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 between the two upper ribs, bounded laterally by the pleuras, ante- riorly by the sternum, posteriorly by the upper dorsal vertebras, and having the top of the pericardium for its basis. This cavity is too irregular to admit of com- parison with any thing else without a hazard of com- municating 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 obliquity of the first rib must be taken into consideration. Considering the spine as a vertical column, the first rib, so far from be- ing 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 con- siderations arising from a wound in the lower part of the neck, as a ball or sword passing through horizon- . 182 OF THE TRUNK. tally 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, having a ligamentous feel, and of 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, (Vena Innominata) after crossing, by an ob- lique descent, the upper portion of the sternum, joins the descending cava about an inch above the place where the latter penetrates into the pericardium. Be- hind this transverse vein are the top of the arch of the Aorta, the origin of the Arteria Innominata, the left Carotid, and the left Subclavian Artery. The oeso- phagus makes a vertical descent just before the dorsal vertebras, 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 removed from the upper end of the sternum only the thickness of the transverse vein, and is very accessible 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 innominata * Eclectic Repertory, Vol. 9, p. 1. VISCERA OF THE THORAX. 183 varies much in length before its division into subclavian and carotid; I have examples of it from half an inch to two inches, but the general length is about sixteen lines. In this dissection the phrenic nerve is seen to descend in contact with the internal edge of the scalenus anticus muscle, and passing between the subclavian 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 side of the internal jugular vein, and gets into the thorax between the subclavian artery and vein near the origin of the subclavian artery. The trunk of it passes along the side of the trachea, and behind the root of the lungs to the oesophagus 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 sub- clavian of the right, and the aorta on the left side. About the root of the lungs, the Pulmonary Plexus is detached from the Par Vagum nerve. The sympa- thetic nerve lies closer to the vertebras, and sends off from its two inferior cervical ganglions principally, the branches which supply the heart, by the cardiac plexus. In the thorax it continues its course by the heads of the ribs, and sending off the greater and lesser Splanch- nic nerves is distributed in a manner to be described hereafter. In making this dissection it must be observed that 184 OF THE TRUNK. from the lower part of the thyroid gland, the con- densed membrane called Fascia Profunda Cervicalis, which seems to afford protection to the upper opening in the thorax, and is extended to the upper edge of the sternum, has beneath it, connecting the vessels and other parts together, a loose, vascular, adipose, and cellular matter, which must be removed 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. longitudinally 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 the lungs, we see the parts contained in the posterior mediastinum and what is meant by it. To the left is the aorta, which gradually gets to the front of the dorsal vertebras in the lower part of the thorax, as it penetrates the crura of the diaphragm. 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 me- diastinum and forms an arch at its termination where it joins the descending cava, over the root of the right lung. The Thoracic duct enters the thorax between VISCERA OF THE THORAX. 185 the crura of the diaphragm, and passes nearly in the middle line between the aorta 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 terminates in the angle produced by the junction of the left internal jugular and sub- clavian vein. The Par Vagum is strictly within the limits of the posterior mediastinum, the Sympathetic is not. ' 24 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 established by imaginary planes passing through the subject. Draw a line from the superior part of the crista of one Ilium, as it appears through the skin, to the superior part of the other; strike a perpendicular then from the anterior inferior spinous process of the Ilium 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 of the ribs. These four lines, two vertical and two horizontal, which represent as many planes, form with the peri- phery 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 Hypochondriac. The region which has the navel in its centre is the Umbilical, and on its sides are the Right and the Left Lumbar Region. Below the um- MUSCLES OF THE ABDOMEN. 187 bilical is the Hypogastric Region, and on the wings of the latter are the Right and the Left Iliac Region. Some anatomists call the pit around the ensiform cartilage the Scrobiculus Cordis, and a small space just behind, 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 abdo- men, 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 com- mencement above, extending obliquely towards the armpit, till it reaches the side of the chest. The second terminates and a third commences there, having a sweep backwards, parallel in its direction with the margin of the cartilages of the ribs, and equidistant from it. The third cut by being 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 integuments of the side of the belly, de- 188 OF THE TRUNK. scribes 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 (simple as the circumstance may appear,) to under- standing the broad muscles of the abdomen well, is the imperfect manner in which the integuments are opened by dissectors: and there is no dissection more apt to be spoiled, than the one in which we are now engaged, 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 to turn the flap downwards. But few strokes of the knife will be made, before the upper fibres of the exter- nal oblique muscle will be exposed. The flap is now to be entirely dissected 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, seeing that he detaches fully the cellular membrane from the muscular fibres; by cutting in the same direction with the latter, he will leave them clean and brilliant, and the transition to the broad tendon connected with them, will be com- paratively easy. In this dissection, as indeed in all others of the mus- cles I cannot attach too much importance to cutting parallel with the fibres; it is absolutely essential to the beauty of the display, and indispensable to a person MUSCLES OF THE ABDOMEN. 189 desirous of success in practical anatomy. A dissec- tion done in any other manner is unfit for study from its obscurity, and offensive to inspect from its rough- ness. The sum of directions to make a good dis- sector of muscles, is to cut in the line of the fibres, close to them, and to keep the cellular membrane tense. There are five pairs of muscles to the abdomen, three broad and two narrow. 1. Musculus Obliquus Externus, arises from the eight inferior ribs by muscular and tendinous digitations attached near 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 sternnm, to the symphy- sis of the pubes. It is inserted into the whole length of the linea alba, and into the anterior half or two thirds of crista of the Ilium, by muscular fibres posteriorly, and tendinous anteriorly. And from the anterior superior spinous process, the tendon stretches to the body of the pubes, forming thereby the ligament of Poupart. In the middle line of the body, the tendons of the three broad muscles on each side of the abdomen unite 190 OF THE TRUNK. to form the Linea Alba, which extends from the ster- num to the pubes. From two to three inches in the adult on each side of the linea alba, but more distant from it above than below, is another line formed by the same tendons, which is the Linea Semilunaris. The navel, which originally was a hole for the passage of the umbilical vessels, and in the adult, is commonly depressed into a pit, now appears in the linea alba as a protuberance composed of condensed cellular mem- brane. Just at the navel there appears a line crossing the linea alba, and extending from one linea semiluna- ris 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 pubes is a fourth, but it is generally imperfect. These are the Lineas Transversas, and they are formed by tendinous matter in the substance of the recti muscles, connecting them to their tendi- nous sheath in front. The most interesting insertion of the tendon of the external oblique is, the part constituting Poupart's Lig- ament. The latter, as it approaches the pubes from the Ilium, 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 of External Abdominal Ring. The tendon forming its upper boundary, is inserted into the symphysis pubis, and into the pubes of the opposite side, by fibres which are interwoven with and decussate MUSCLES OF THE ABDOMEN. 191 those of its fellow. The tendon forming the lower margin of the ring, is inserted into the spine of the pubes, and into its crest for an inch. The portion in- serted into the crest of the pubes, is Gimbernat's ligament, which, it will be readily understood, means only a part of Poupart's. The ring in the external oblique is rather triangular than round; its base is formed by the body of the pubes, and its point is at ,the place where the tendon separates. The latter is kept from parting still further, by a fasciculus of tendinous fibres which runs across it. The tendinous sides of this opening are called its Columns, and from their situation, internal and external, 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 viscera of the ab- domen, and brings the pelvis 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 Ilium. This process will enable the student to gain a a more satis- factory view of its insertion into the spine and crista of the pubes. 192 OF THE TRUNK. 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 Ilium, and fleshy from the upper half of Poupart's ligament. Though the fibres of this muscle, in gene- ral, decussate the fibres of the external oblique all of them do not, for the lower are brought gradually to pursue the same direction towards the symphysis of the pubes. Near the Linea Semilunaris, the muscular fibres cease, and the tendon begins. It is inserted into the cartilaginous margin, formed by the six inferior ribs; that is, by fibrous 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 pubes. The tendon of this muscle divides into two laminas, in a manner which will be better explained presently, after the rectus and pyramidalis muscles have been dis- sected and turned down. 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, vertebras, ilium, and exter- MUSCLES OF THE ABDOMEN. 193 nal half of Poupart's ligament; by beginning near the spine of the ilium, where it is separated more distinctly from the muscle below, by an artery, a vein, and cel- lular substance. 3. The Transversalis Abdominis, arises by the Fascia Lumborum, from the transverse processes of the last dorsal, and of the four upper lumbar vertebras, and also by it from the posterior third of the spine of the ilium. It likewise arises fleshy from the anterior two- thirds of the spine of the ilium, and from the upper half of Poupart's ligament; tendinous and fleshy alter- nately, from the inferior margin of the thorax formed by the cartilages 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, into the side of the ensiform cartilage, filling up the vacancy between it and the cartilages of the sixth and seventh ribs, and into the linea alba, from the extremity of the sternum to the pubes. Use, to compress the contents of the abdomen. 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 25 194 OF THE TRUNK. origin will then be seen as a flat tendon of an inch or more in breadth, coming from the symphysis pubis and the upper posterior part of the body of the pubes. The muscle increases gradually to the breadth of three or four inches in its ascent. The tendinous intersec- tions, confining it to the tendinous sheath in front, are established at the places mentioned as lineas transversae, 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 and is about three inches long. It arises somewhat thick, tendinous, and fleshy from "the upper part of the pubes, from near its spine to the symphysis between the rectus behind and the insertion of the ex- ternal oblique before, and is fixed in a sheath formed by the separation of the common tendon of the trans- versalis and internal oblique muscles. It tapers to a point above, and is Inserted into the linea alba and internal edge of the rectus, two thirds of its own length, by beginning about an inch above the pubes. It strengthens the lower part of the abdomen.* The Rectus and the Pyramidalis muscles are now * This muscle is often wanting. MUSCLES OF THE ABDOMEN. 195 to be detached from their origins and turned aside. By doing so we become sensible of an arrangement of the tendons of the broad muscles always difficult to de- scribe intelligibly, and generally imperfectly understood. It is this; at the linea semilunaris the tendon of the internal oblique and that of the transversalis unite in- timately, and just beyond this junction two laminas are formed, which enclose the rectus muscle. The anterior lamina is one-half of the tendon of the internal ob- lique 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 origin to insertion. The posterior lamina is made by the posterior half of the tendon of the internal oblique united at the linea semilunaris to the tendon of trans- versalis; and which in this manner passes behind the rectus muscle from the cartilago ensiformis to a line half-way between the umbilicus and the pubes. 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 muscles all terminate in the linea alba from the thorax to the pelvis, but the inspection of the part will qualify the the term so as to prevent mistakes. 196 OF THE TRUNK. The Cremaster muscle is commonly attributed ex- clusively 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 his- tory 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 pubes, and as it descends it comes in contact with a fasciculus of these fibres and takes it along. This fas- ciculus constitutes the Cremaster muscle, which, in adult life and in a strong muscular subject, is seen descend- ing on the outside of the spermatic chord, and spread- ing over the anterior part of the tunica vaginalis in arches with their convexities downwards, then rising on the inner side of the chord and inserted into the spine of the pubes.* It draws up the testicle. As one becomes acquainted with the dissection of this part by operating on a number of subjects, he will be sensible that there are differences in individuals * Mr. J. Cloquet, of Paris, has given this explanation of the forma- tion of the cremaster and it sometimes is manifest in the adult; it is, however, not in accord with Mr. Hunter's account of it, neither does it'correspond with what I have witnessed in the male buffalo, in a specimen given to me by Dr. R. Harlan. Mr. Hunter has seen it running up to the testis, while the latter was still in the loins. MUSCLES OF THE ABDOMEN. 197 which render the established descriptions occasionally unsuitable. One of the most usual is the deficiency of the transverse muscle in that part, the origin of which is usually attributed to the upper half of Pou- part's ligament. In this case the internal oblique has increased thickness, and of course, the cremaster 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 pubes. It will thus be seen that they form below, a common tendon, which is inserted, for an inch, into the crista of the pubes behind Gimber- nat's ligament, into its spine, and into that part of its body which is behind the external abdominal ring; and that just within and above their insertion the same common tendon splits into two laminas, one going before, the other behind the pyramidalis muscle, thus forming a sheath for it as just stated. 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 over- lapping the internal edge of the other; and by a triangular ligament called, by Mr. Breschet its dis- coverer, the Superior Pubic Ligament. 198 OF THE TRIJNK. 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, and for three or four inches along the inner margin of the thigh; commence another at right angles with the beginning of this, and continue it from the umbilicus in a straight line towards either flank; make a third incision parallel with the first, beginning an inch behind the anterior superior spinous process of the ilium, and terminating in the second incision. The flap of skin thus marked out, must be turned down over the thigh by a careful dissection, which will bring into view the fascia super- ficialis abdominis. The Fascia Superficialis consists of condensed cel- lular membrane, which may be considered as taking its origin on the front of the thigh, and extending in front of the abdominal muscles, as high up as the thorax; INGUINAL HERNIA. 199 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 about the groin have been pressed upon and thickened by the irritation of hernial protusion it is better developed. 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 be- low Poupart's ligament. On the tendon of the external oblique it is more condensed; branches of the femoral artery are also seen in it there; one longer and larger than the others, the arteria ad cutem abdominis of Haller, winds over Poupart's ligament and runs upwards somewhat in the line of the epigastric artery, being distributed to the skin of the abdomen; the division of it will produce sufficient hemorrhage to require atten- tion. On the symphysis pubis and about the external ring the laminas of the fascia superficialis are multi- plied, and it has more of the character of common adipose matter, as in most 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 increase. From the pubes it may be traced as a condensed cel- lular membrane along the penis to its extremity, and, according to Mr. Colles of Dublin, when matter is * 200 OF THE TRUNK. formed beneath it, it is apt to create fistulous sores on this organ. A thin lamina o( this membrane may also be traced for some distance along the spermatic chord, to the testicle. The Fascia Superficalis, under the name of Tunica Abdominalis, is well developed in animals with a large and projecting belly, particularly in the large ruminan- tia and the solipedia. It has a yellowish tinge, is very elastic and strong, and well calculated to support the viscera in them. In dissecting at the Abdominal Ring, do not work too closely between the spermatic chord and the margin of the ring; by which precaution we avoid cutting the process of the fascia superficialis that unites the two. This process arises from the margin of the ring all around: it passes immediately to the spermatic chord, 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 con- stituent parts of the chord and the cremaster muscle. This cellular substance, the cremaster muscle, and the fascia superficialis form, in scrotal ruptures, a thick lamina over the hernial sac, called Tunica Vaginalis Communis. Next make an incision through the fascia superficialis and the tendon of the external oblique, commencing at INGUINAL HERNIA. 201 the Linea Semilunaris a quarter of an inch above the upper margin of the external 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 being downwards, and almost touching the middle of Poupart's ligament. The tendon of the ex- ternal oblique, bordering on the incision, should be then turned upwards and downwards, by which a good view is given of the inferior part of the internal oblique muscle where it arises from the iliac or upper half of Poupart's ligament, and is inserted into the crista of the pubes just behind the external abdominal ring. The origin of the cremaster muscle is well seen, and the constitu- ent parts of the chord, as they are about to enter into the external ring. Separate the inferior margin of the internal oblique from Poupart's ligament, and turn it upwards, begin- ning near the anterior spine of the ilium, where the distinction between the internal oblique and the trans- versalis is better marked. The lower part of the transversalis is thus exhibited placed behind the inter- nal oblique, and having the same origin from Poupart's ligament and insertion into the Pubes. The raising of the internal oblique brings into view more of the sper- matic chord near the external ring. The Transversalis Muscle is then to be detached from Poupart's ligament, and raised up. This gives a 26 202 OF THE TRUNK. complete view of the spermatic chord, consisting here of its vessels, nerves, and excretory duct, united by cellular membrane. The upper part of the visible por- tion of the chord, is about half-way between the anterior spine of the ilium and the symphysis of the pubes, and penetrates the fascia transversalis. The fascia trans- versalis is placed immediately behind the transversus muscle, between it and the peritoneum. The opening of the fascia transversalis, which permits the chord to pass, is called the Internal Abdominal Ring, in order to distinguish it from the opening in the tendon of the external oblique, called the External Ring. The in- ternal ring is rather nearer to the symphysis pubis than to the spine of the ilium. It will now be under- stood 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, Inguinal, or Spermatic Canal as giving passage to the spermatic chord. 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 fascia transversa- lis, and above, this canal is overhung by the internal oblique and transversalis muscles. It should be ob- served that the spermatic chord, after penetrating the fascia transversalis, does not cross, directly, the inferior edge of the internal oblique and transversalis at right angles; but it crosses them very obliquely, its inclina- tion being towards the pubes, so that the spermatic INGUINAL HERNIA. 203 chord can only be considered 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 trans- mits the spermatic chord is reflected by a thin process to the chord, and insensibly terminates in its cellular substance. At the posterior or ventral face of the Ex- ternal Ring, the fascia transversalis is not in contact with the chord, but that part of the tendon of the in ternal oblique and transversalis which is inserted into the crista of the pubes, and forms a sheath for the pyramidalis muscle, is placed between them, and secures this opening. The incisions which were originally made only through the skin of the abdomen are now to be carried through the parietes of the same 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 sur- face covered by peritoneum is divided in the iliac region near the middle of Poupart's ligament into two super- ficial fossae by a narrow falciform process of the peri- toneum. The process arises from the side of the bladder and extends upwards and inwards towards the umbilicus, stopping about two inches short of the um- bilicus. It is broader below than it is above, and its loose edge is turned towards the abdomen. By strip- c 204 OF THE TRUNK. ping down the peritoneum we shall see that this falci- form process is simply a duplicature of it, occasioned by a fibrous chord, the umbilical ligament of the blad- der, which once was the umbilical artery of the foetus. This chord passes near the pubic margin 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, corres- ponds with the internal abdominal ring, and frequently a little pouch of peritoneum enters the latter. The fossa on the inner or pubic side of the falciform pro- cess is just behind the external ring, but separated from it by the fascia transversalis, and the tendon of the lower parts of the internal oblique, and the trans- versalis muscles where they are inserted into the pubes, and form the sheath of the pyramidalis. The two fossae indicate the points where inguinal hernias com- mence, the proper inguinal protusion beginning gene- rally in the external fossa, and the ventro-inguinal in the internal fossa. We should here notice the looseness of the attachment of the peritoneum by cellular sub- stace 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 behind is extremely satisfactory. For a proper knowledge of this membrane, the profession is indebted to the labours of Sir Astley Cooper, and much of the zeal with which INGUINAL HERNIA. 205 the anatomy of hernia has been investigated, in latter years is attributable to him. The fascia transversalis is a thin tendinous membrane most generally, occasion- allv it more resembles condensed cellular membrane. It arises from the internal or abdominal edge of Pou- part's ligament, and from the crista of the pubes just behind the insertion of the tendon of the internal ob- lique and transversalis muscles, and is extended up- wards on the posterior face of the transversalis muscle to the thorax. At its origin it is attached to the in- ferior edge of the transversalis and internal oblique, particularly the part of the edge between the internal ring and the pubes. It is also attached to the exterior margin of the rectus abdominis. The internal abdo- minal ring or opening in this fascia 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 crural arch than they are higher up.* Removing the peritoneum from the iliacus internus muscle, we see the spermatic vessels descending from * Were it not for the important influence of the fascia superficialis and the fascia transversalis upon hernia, and the consequent necessity of a minute knowledge of them, the description might be much curtailed in considering them in their proper light, to wit, as the sheaths of muscles; for it is now sufficiently apparent that the first is contiguous to the external oblique and the second to the transverse muscle. 206 OF THE TRUNK. the loins to the internal ring, where they are joined by the vas deferens coming from the pelvis. As they en- gage under the edge of the internal oblique muscle, after penetrating the ring, the cremaster muscle is de- tached to spread itself over them. The spermatic chord, thus constructed, passes through the abdominal canal in the manner mentioned, obliquely downwards and inwards; emerging from the external ring it de- scends vertically, lying rather upon the outer column of the ring than upon its base. On the posterior face of the fascia transversalis, be- tween it and the peritoneum, is the Epigastric Artery. The epigastric arises from the external iliac as the latter is about to go under Poupart's Ligament; it ascends inwardly along the internal margin of the internal ab- dominal ring to the exterior margin of the rectus ab- dominis muscle, which it reaches after a course of two and a half or three inches. The spermatic chord, in getting from the abdomen to the abdominal 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 peri- toneum through the internal ring and along the abdo- FEMORAL HERNIA. 207 minal canal into the groin, the constituent parts of the chord being behind the sac and separated by it 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 insertion of the internal oblique and transversalis muscles, a protusion immediately from behind the external ring may occur, in which the whole chord, including the cremaster, is at the outer margin of the sac. In the first species, or the Inguinal Hernia, 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. The anatomical arrangement of the parts concerned in inguinal hernia in the female is the same as in the male, except that the round ligament of the uterus sup- plies the place of spermatic chord, and there is no cre- master muscle. SECTION III. Of the parts concerned in Femoral Hernia. The study of Femoral Hernia should be commenced with precise ideas, of the concave edge of the os inno- minatum, which terminates externally by the anterior 208 OF THE TRUNK. superior 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 suffi- ciently well for this dissection; the male black is, there- fore, most frequently resorted to in our school. If the subject have suffered somewhat from a previous infil- tration or dropsy of the cellular membrane, the facility of separating the different layers of fascia from each other is much increased. Make an incision through the skin from the umbilicus to the root of the penis, dnd extend the lower end of the incision around the penis along the internal margin of the thigh for six inches. Commence a second incision 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 termi- nation of the first and carry it to the outer side of the thigh. A flap, consisting 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 abdominis, which lies immediately beneath, and which is next to be dissected up. The Fascia Femoris is beneath the fascia superficialis abdominis; its general character and arrangement are FEMORAL HERNIA. 209 introduced into the account of the lower extremity, but there are other and minute circumstances in its dispo- sition at the groin, indispensable to a knowledge of femoral hernia. When the fascia superficialis is clear- ed away, the fascia femoris is seen to arise at the groin along the anterior edge of Poupart's ligament, from the spine of the ilium to within a short distance of the spine of the Pubes. This portion of it is thin, and through it the sartorius muscle'may be seen;'jt is there- fore called the sartorial fascia. The fascia femoris arises also from the crest and spine of the pubes, and along its ilio-pectineal ridge which is a continuation of the same; this latter portion covers the pectineus muscle, and is called the pectineal fascia. The pecti- neal fascia is behind the femoral artery and vein, and the sartorial fascia is before them. The Saphena Vein, placed between the fascia fe- moris 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 beneath 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. Imme- diately 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, 27 210 OF THE TRUNK. and extends from the junction of the sartorial and pec- tineal fascia to the crista of the pubes; it is frequently reticulated. At the upper end of this crescent, the sartorial fascia terminates in a point or angle which is directed deeply towards the pubes. The upper margin of the angle is closely connected with the edge of Gimbernat's ligament and the point is inserted into the crista of the pubes in the same line with Gimber- nat's ligament but exterior to it, just at the internal margin of the femoral vein. This angular production or elongation of the sartorial fascia is called Hey's or the Femoral Ligament. The free edge of it is turned towards the femoral Blood-vessels by a sort of half twist. By introducing a finger under Hey's ligament into the abdomen, we find that the crural arch of 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, from the iliacus internus and psoas magnus, which brings into view the fascia iliaca. The Fascia Iliaca is a tendinous membrane which FEMORAL HERNIA. 211 lies on the iliacus internus and psoas magnus muscles, and 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 magnus it is connected with the brim of the pelvis, and sinks into the cavity of the pelvis, being continuous with the Aponeurosis Pelvica; and below, it is inserted into the edge of the crural arch from the anterior superior spinous process of the ilium almost to the pubes. 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 pubes which gives origin to the pec- tineus muscle, and that it is continuous with the pec- tineal fascia. If the student should have a preparation in which every thing is removed from the os innomi- minatum except the insertion of the tendon of the ex- ternal 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 between the bone and the arch; and the insertion of Gimbernat's ligament from the spine of the pubes, an inch or more along its crista. He will then understand 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 profusions would be constantly occurring. 212 OF THE TRUNK. The iliac vessels pass beneath the crural arch on the inner margin of the psoas magnus muscle, the vein be- ing nearest the pubes and the artery at the outer £ide 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 be traced to the crista of the pubes, and that it is so connected with the vessels that no opening for hernia exists between them, or 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 Gimbernat's ligament an opening appears called the Crural or Femoral Ring, and is the place where femoral hernia commences. This open- ing is generally occupied by a lymphatic gland and a lamina of condensed but loosely attached cellular sub- stance, called sometimes the Cribriform Fascia, conti- nuous with the Aponeurosis 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 concep- tions of the attachment of the fascia iliaca with the crural arch, and its continuity with the fascia pectinea, will be much improved. The femoral vessels are enveloped Dy a sheath. To see this distinctly, separate the fascia transversalis from the transverse muscle; cut vertically through the falciform process of the fascia lata femoris, over the FEMORAL HERNIA. 213 artery, and continue the cut also through Poupart's Ligament, taking care to injure the fascia transversalis as little as possible. To render this part of the exami- nation convenient, only a narrow flap of the abdomi- nal muscles should be left at the groin. By turning towards the symphysis pubis the falciform process, with that part of Poupart's ligament to which it ad- heres, 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 connexion with the pecti- neal fascia, gives a layer to the posterior face of the femoral vessels. The sheath of the femoral vessels is by this method of examination proved to be formed from the fascia transversalis in front, and the fascia iliaca behind. Mr. Colles has adopted a very satis- factory 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 pro- ceeds the membranous neck which surrounds the femo- ral vessels, and constitutes their sheath. This sheath is very separable from the sartorial fascia in front, and the pectineal fascia behind, and may be traced, easily, to the entrance of the saphena vein into the femoral. On the thigh, just below Poupart's ligament 214 OF THE TRUNK. it has a number of foramina in it occasioned by the passage of the lymphatic vessels 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 artery 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 ligament, a close fibrous connexion is formed from them to the sheath both anteriorly and posteriorly, which sends a partition between the artery and the vein, and a partition also on the inner side of the vein. By such arrangement hernial protusions 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 Crural Ring, as stated. When an intestine descends, it passes into the femo- ral sheath on the inner side of the iliac vein, it follows 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. The route thus indicated con- stitutes the Femoral Canal of Cloquet. Afterwards, FEMORAL HERNIA. 215 if the hernia increase; instead of continuing to descend, it turns upwards and outwards, towards the anterior spinous process of theJlium. 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 Ligament 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 in- ternal margin of the commencement of the sheath of the femoral vessels instead of by Gimbernat's liga- ment. He says that this orifice remains with a sharp and distinct edge, even when Gimbernat's liga- ment is taken completely out of the way, and that the edge of Gimbernat's ligament, supposed to consti- tute this stricture, stops several lines short of the Crural Ring. A dissection performed in the manner that he recommends, is unquestionably 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. 216 OF THE TRUNK. SECTION IV. Of the Contents of the Abdomen. For common examination, a crucial incision through the parietes of the Abdomen: from the sternum to the pubes on the left of the navel; and from one side to the other, on a line with the umbilicus, but a little be- low it, answers very well. The flaps, thus made, be- ing 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 anterior edge. 2. The Stomach, when not distended much, is confined to the lower half of the Epigastric region and to the right inferior part of the left Hypochon- driac. 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. CONTENTS OF THE ABDOMEN. 217 4. The small Intestines lie in the Umbilical, Hypo- gastric, part of the Iliac regions, and also in the Pelvis, when the viscera of the latter are not dis- tended. 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 distension of the stomach; it then gets to the left Hypochondriac, being commonly higher up in it than in the right Hypochon- driac; 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. The Omentum Ma jus is in front of the small in- testines, and most frequently found gathered up in the Umbilical region. If it be not diseased, it may be drawn downwards to the pelvis, and spread out so as to conceal all the front of the intestines. 7. The Pancreas is at the back of the Epigas- tric Region, behind the stomach; it lies horizontally, and extends from the right of the spine into the left Hypochondriac region. It cannot be seen without cutting through the omentum majus, and turning the stomach upwards. 8. The Kidneys and Capsulas Renales are in the 28 218 OF THE TRUNK. Lumbar Regions, at their back parts. They should not be sought for at this stage of the dissection. 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 in what is said of the occupancy of the regions, it is understood that the subject is on his back. Wrhen one stands upright, the lumbar vertebras are more convex in front, and the abdomen more pro- tuberant 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 pubes not many degrees from the hori- zontal line. Most of the viscera descend, but more particularly the liver, which being no longer sustained by the false ribs, and being influenced by its heavy inert mass, may, in many cases, be felt externally along the right inferior margin of the thorax. 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 dia- phragm 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. CONTENTS OF THE ABDOMEN. 219 It should be well recollected that the abdominal cavity is always full, there being no unoccupied space in it; hence, whenever any viscus has an inordinate growth, or a tumour forms on it, or an effusidn 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, semitransparent 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 Fal- lopian tubes. It has a double use; in consequence of covering the viscera, it is so reflected from them to the sides of the abdomen, that its processes keep the viscera in their proper places, and therefore answer as liga- ments. Again, its internal surface being smooth, highly polished, and continually lubricated by a thin albuminous fluid corresponding with the synovia of the 220 OF THE TRUNK. joints, the motions which the viscera have upon each other in exercise, and in the peristaltic movements of the bowels, are much facilitated. The manner in which a double night-cap is applied to the head, will afford the easiest conception of the reflections of the peritoneum. If there were only one viscus in the belly, and that of a somewhat re- gular outline, as the spleen, 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 spleen; the other is loose, and is equivalent to the peritoneum, where it is in contact with the parietes of the belly. It is also evident from this, that none of the viscera can be said to be within the cavity of the peritoneum; that they are all on its outside; and that a viscus in getting a coat from the peritoneum, merely makes a protusion into its cavity. Starting with this most simple 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 proposition is imme- diately intelligible; and as a last step from it, 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, with exceptions to be stated, derive an external coat from the peritoneum. The reflections of peritoneum forming the ligaments of the liver will be best described in connexion with CONTENTS OF THE ABDOMEN. 221 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 Omenta, Fatty Appendages of the Colon, the Mesentery and the Mesocolon. 1. There are four Omentums. Omentum Minus or Hepatico-Gastricum, Omentum Majus or Gastro-Coli- cum, Omentum Gastro-Splenicum, Omentum Colicum. a. The Omentum Minus extends in a transverse di- rection from the transverse fissure of the liver; from the right of the lobulus Spigelii at the posterior half of the umbilical fissure; and from the inferior face of the diaphragm; to the lesser curvature of the stomach from the end of the oesophagus to the pylorus and duodenum, It is composed of two laminas which, near the stomach, are separated by the coronary vessels. It has always but an inconsiderable quantity of fat in it. Its right margin is commonly called the Capsule of Glisson, and contains the hepatic vessels. b. The Omentum Majus, or Gastro-Colicum, is an irregular quadrilateral membrane having its base up- wards. The latter is fixed anteriorly to the greater curvature of the stomach, and posteriorly to the trans- 222 OF THE TRUNK. verse arch of the colon. It hangs loose in its inferior part, and is sometimes found spread over the intestines as low as the pelvis; it is, therefore not improperly compared to an apron. On its right side it is contin- ued into the omentum colicum, and on the left into the gastro-splenicum.. It consists of two laminas, the an- terior is fixed to the stomach, the posterior to the colon. Each of these laminas 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 internal 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. By searching for the neck of the gall bladder, we shall find near it under the capsule of Glisson, the Fo- ramen of Winslow, an opening which conducts into the bag of the omentum majus. It is large enough to admit easily two fingers. 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 cavity is bounded above by the omentum minus and stomach; in front by the two laminas sent from the stomach; behind and below, by these laminas being reflected upwards and joining the colon, and posteriorly and above, by the upper lamina of the mesocolon which is extended to the Lob- ulus Spigelii. By a little reflection it will be understood CONTENTS OF THE ABDOMEN. 223 that I have described an uninterrupted cavity, begin- ning at the lobulus spigelii by the omentum minus, 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 obscure propositions in descriptive anatomy, even when the subject is before a young student. It is a point well worth mastering, as, when this is accomplished all other difficulties, in studying the reflections of the peritoneum, are much diminished. c. The Omentum Colicum is a prolongation of the omentum majus, from the internal side of the right ascending colon, and from the adjacent part of the transverse. It is filled with fat from the same causes as the preceding, but consists of only two single laminas. d. The Omentum Gastro-Splenicum is that process of peritoneum which extends from the large extremity of the stomach to the spleen; it may be considered a prolongation of the omentum majus, and encloses in its duplicature the arteries and veins called Vasa Brevia. e. The Appendicul^e Epiploic*: are little processes of peritoneum, filled with fat, appended at irregular in- tervals to the anterior sides of the cascum, colon, and the upper part of the rectum. 224 OF THE TRUNK. The Mesenterium is extended obliquely across the spine from a line parallel with the second lumbar ver- tebra 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 pendulous having the intestines connected with it, has its circum- ference increased to many feet, which causes it to lie in folds. The mesentery attaches the left extremity of the duodenum, the jejunum, and ileum to the spine. It consists of two laminas 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 intestine to the back of the abdomen. The posterior part of the cascum is in contact with the iliac fascia and is tied down to it. 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 mesocolon is long, and forms a complete and moveable parti- tion between the upper and the lower parts of the abdomen, which permits the colon to ascend and de- scend according to the distension of the 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 continues into the meso- rectum. CONTENTS OF THE ABDOMEN. 225 Of the Ventriculus, or Stomach. The stomach is a conoidal sac curved considerably. As was stated, it is in the epigastric region; in contact above with the diaphragm, with the left lobe of the liver and the lobulus spigelii; on the left with the spleen; behind with the pancreas; and below with the colon and mesocolon. The stomach has a very great ob- liquity in its situation, the right extremity being much lower down than the left. The exterior of the stomach presents two faces, two orifices, two curvatures, and two extremities. When the stomach is nearly empty it becomes somewhat flattened, and then exhibits the Anterior and the Posterior face; in a state of distention, the first looks obliquely upwards, and the latter obliquely downwards. The angle, formed with the oesophagus, is increased according to the degree of distension. 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, form- ed by the junction of the oesophagus with it, is at the upper edge of the stomach, and some distance from the extreme left. The curvatures are the Great and Small. The first includes the great extremity and the inferior edge of the 29 226 OF THE TRUNK. stomach to the pylorus; the small 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 cardiac orifice; it is smaller in proportion in children than in adults. The stomach consists of four laminas. The external 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 pylorus. At the latter they are collected into a ring of considerable thickness, which, making a marked prominence internally, helps to constitute the valve of the pylorus. The muscular fibres go in three directions. The first being longitu- dinal, are continued from similar ones of the oesophagus and 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, in an especial manner, which assists in forming the pyloric orifice. The third and most profound set of muscular fibres is oblique, and forms two large bands. One is extended from the left side of the cardia over the an- terior and posterior faces of the stomach; and the other is prolonged from the right side of the same orifice CONTENTS OF THE ABDOMEN. 227 over the great extremity also before and behind, where it supplies the scarcity 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 ves- sels and nerves to the latter. The fourth or Internal Coat of the stomach, called, also the Mucous or Villous, is of a light red. It is like velvet, and is thrown into very irregular folds, accord- ing to the degree of contraction of the stomach. At the pyloric orifice it forms a circular fold constitut- ing the pyloric valve and having a round hole in the centre. At the base of this valve the muscular fibres make a distinct ring. • 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-colic valve, the other from this latter to the anus. The first is Intestinum Tenue, the second Intestinum Crassum. This canal like the stomach consists of four coats, peritoneal, muscular, nervous, and villous. 228 OF THE TRUNK. The small Intestine, or Intestinum Tenue, is divided somewhat artificially, by anatomists, into three parts, Duodenum, Jejunum, and Ileum. 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 between the two laminas of the Mesocolon on the right side. Here it forms a round elbow, and crosses the spine obliquely upwards, making its appearance to the left of the second lumbar vertebra, where it is continued into the mesenteric 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 laminas of the mesocolon, but have no peritoneal coat; and the termination is both moveable, and has a peritoneal coat. The partial de- ficiency of peritoneal coat, is said to be the cause why the duodenum is susceptible of an enlargement, 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. Beneath is the CONTENTS OF THE ABDOMEN. 229 coat of cellular membrane connecting it with the mu- cous or villous coat. The internal coat is reddish, tinged with bile, and occupied by a great number of rugas or folds. They are transverse and oblique, very near each other, about three lines broad, and as pro- minent in the distended as the undistended gut; these constitute the Valvulas Conniventes. Many mucous follicles exist in this intestine, and mucous glands, call- ed Glandulas Brunneri; the latter are particularly ac- cumulated about the pyloric orifice. It is, in the pos- terior part about four inches from the stomach, that the orifices of the pancreatic and hepatic 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 valvulas 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 diameter 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 accus- tomed 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 laminas of mesentery are 230 OF THE TRUNK. loosely applied against each other where they join the intestine, and are separated in its distentions, as far as the first row of the mesenteric arches of blood-ves- sels. Cases are reported, in which it has had appen- dicular epiploicas and cul-de-sacs projecting from its sides. I have never seen the former, but of the latter, a specimen was presented to me some years ago, taken from a child by the late Dr. Edward Barton; and another specimen now belongs to the Wistar Museum, obtained in the dissecting rooms. The mucous or internal coat of the Intestinum Tenue, differs from that of the stomach, in resembling more the downy cuticle of an unripe peach. The little pro- jections from it, are called Villi. It abounds with mucous follicles and glands; the latter consist in those of Brunner which are insulated from each other and may be seen at intervals along the whole intestine: and in those of Peyer which make about thirty patches of an elliptical shape and of various sizes towards the lower end of the Ileum. 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 intestine, being very large at its commencement when inflated, and diminishing much to the lower end of the sigmoid flexure. Anatomists call its commencement, or that part below the ileo-colic valve, Cascum or Caput Coli; CONTENTS OF THE ABDOMEN. 231 and the remaining portion, which is by far the longest, the Colon, until it reaches the pelvis, when it becomes Rectum. The Caput Coli is about two inches in length, and is fixed to the Iliac fascia by peritoneum and loose cel- lular membrane. At its inferior extremity, towards the left is the Appendicula Vermiformis, a blind cavity of four coats, about four inches long, and of the size of a turkey quill, enclosed in a duplicature of peritoneum. 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, stran- gulation. 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 frequently 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 mus- cular fibres are much more conspicuous ; they are col- lected into three bands, which commence at the head of the colon, and extend to the upper part of the rec- tum; one is superior, another inferior, and a third an- terior. They are equidistant from each other. These longitudinal bands produce the cells of the colon, by drawing its extremities nearer together. The cells are separated laterally, by partitions or buttresses formed of a doubling of all the coats of the intestine; whereas 232 OF THE TRUNK. in the small intestine, the valve or doubling belongs ex- clusively to the mucous membrane. 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 removed, and the intestine elongates consider- ably. The Ueo-Colic Valve, or valve of Bauhin, or Tulpius, 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 cor- responding coats of the colon, the muscular coat of the latter being simply parted. To prevent the further sepa- ration of the muscular fibres, a little ligamentous ar- rangement, called the Retinaculum Morgagni, prevails at each end. When viewed from within the colon, the opening appears as a transverse, or very narrow ellip- tical slit, established by two lips, the superior broader than the inferior. They meet like the gates of the common ship-dock or hydraulic lock; and from being placed transversely, in regard to the cavity of the in- testine, every distention which the latter may suffer from the accumulation of fasces, has a tendency to force this valve, and will, by stretching its extremities, make the lips tighter and more resisting. The internal coat of the large intestine differs very materially from that of the small. It has few or no villi. Near its commencement, it preserves the fungous ap- pearance of the stomach, but about the sigmoid flexure, CONTENTS OF THE ABDOMEN. 233 it is a plain smooth surface. A great many mucous follicles and mucous glands are in it. It has lacteals, but they are not so numerous as in the small intestines. The Rectum will be described with the Pelvis. Of the Liver, {Hepar, Sive Jecur.) The Liver secretes the bile. Its position in the ab- domen and the space it occupies have been mentioned. It is placed in the following relations: above, it is in contact with the concavity of the diaphragm; below, are the Omentum Minus, the Stomach, and the Trans- verse Arch of the Colon; behind, is the Vertebral Column, intercepted however by the lesser muscle of the diaphragm, and the Ascending 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 un- easiness by pressing on the stomach; and when on the back it compresses the ascending cava. Its colour is reddish brown. Its form is happily compared, by Professor Chaussier, 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 following reflections of the peritoneum. From the centre of the diaphragm, and extending from the umbilicus backwards to near the ascending cava, is the Falciform or Suspensory Ligament, con- sisting of two laminas; it is thickened at its anterior 30 234 OF THE TRUNK. edge by what was once umbilical vein in the foetus, but is now converted into a fibrous substance called Round Ligament. 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 falci- form process, and extending from the diaphragm to the posterior edge of the liver, is the Right Lateral Liga- ment ; to the left of the same process, and also extend- ing 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 ligaments forms the Coronary Ligament. Within the circumfer- ence of the coronary ligament the surface of the liver is not covered by peritoneum, and it is attached to the diaphragm by loose cellular substance. The precise shape of the liver is best seen in one re- moved from the body. The following parts are no- ticed by anatomists: its upper surface, its lower sur- face, its right extremity, its left extremity, its anterior edge and its posterior edge. The upper surface is uniformly convex, and presents nothing remarkable but its unequal division by the sus- pensory ligament. The lower surface is very irregularly concave, and on it are the following appearances: From the front to the back edge is a deep fissure corresponding in situ- ation, with the suspensory ligament above, and with it, giving occasion to divide the liver into right and left CONTENTS OF THE ABDOMEN. 235 lobes. This is the Sulcus Umbilicalis, occupied 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 left lobe, for some dis- tance into the right, and occupying about the middle third or fourth of the long diameter of the liver, is the Sulcus Transversalis. In it are the Vena Portarum, Hepatic Artery, and Ducts. The Lobulus Spigelii or posterior lobe is at the back of the liver just to the right of the posterior part of the sulcus umbilicalis. It is like a ridge and terminates forwards in a papilla which is one of the portas of the liver; to the right, the lobu- lus spigelii sends off a small process which unites it with the greater lobe of the liver, and is called the Lo- bulus Caudatus. On the front of the inferior surface between the fore part of the umbilical fissure and the gall-bladder is a flat rising, the Lobulus Anonymus or Quartus ; its posterior extremity, opposite to the an- terior 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 very thin edge. The posterior border or edge is thick, and indented by the spine, but the ante- rior edge is thin. The former is sometimes converted into a complete canal, marked by a short large sulcus for the ascending vena cava; the latter only has the notch for the suspensory ligament already mentioned, 236 OF THE TRUNK. Besides the peritoneal coat, the liver has a second, which covers its whole exterior surface, adhering very closely to the peritoneum on one side, 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 peritoneum, and in parts which naturally are left uncovered 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 cosliac, after hav- ing 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, however, subdivide before they reach the substance of the liver. These branches are between the sinus portarum and the biliary ducts. The vena portarum is formed from the union of all the veins of the intestines, sto- mach, pancreas, and spleen, forming a single trunk about three inches long. It gets to the transverse fissure of the liver, over the duodenum and under the pancreas, and immediately sends off, at right angles, two branches which, collectively, are 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. * See Soemmering's Anatomy. Laennec's Journal de Medecine. CONTENTS OF THE ABDOMEN. 237 At the bottom of the transverse fissure is a lamellat- ed fibrous cellular tissue, closely adhering to the liver, which accompanies the vena portarum, the hepatic ar- tery, 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 spo- ken of as lying on the aforementioned vessels, even before they reach the liver. The hepatic veins arise from the capillary extremities of the hepatic artery and vena portarum; there are three principal 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, five or six little trunks, coming from the posterior surface of the liver, and the lobulus spigelii, which empty into the as- cending cava below the other. The hepatic veins have no valves, and may, in a section of the liver, be read- ily distinguished from other vessels by their lonely course, by their crossing the others at right angles, and by their thinness. All of these vessels of the liver are remarkable for the number of their anasto- moses and the facility of their coriimunication with each other. A minute injection of either pervades all parts of the liver, and the injection if persevered in will fill all the other vessels. By tearing the substance of the liver a good view of its organization may be obtained; 238 OF THE TRUNK. it will then be seen to be composed of an immense num- ber of spherical or polyhedrous grains, {Acini,) united to each other by the cellular tissue of the internal coat. These grains contain the essential and ultimate points of the glandular arrangement, the anastomoses 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 is yet doubtful. The nerves of the Liver will be mentioned at an- other 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 some- what obliquely, 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 towards the left. Its shape is conical, the base being rounded off and the apex curved ; the body di- minishes 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 ramifies a great number of blood-vessels and lymphatics. The third may be considered a continu- ation of the mucous coat of the intestines, but has some peculiarities. On its internal face, it is thrown into irregular tortuous folds or wrinkles of extreme CONTENTS OF THE ABDOMEN. 239 delicacy, in the intervals of which are many round or polyhedrous 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 or more elevated semilunar folds are formed, of the internal membrane: a spiral arrangement is some- times adopted by them. The gall-bladder and the contiguous parts,'after death, are always tinged with bile, which does not occur 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 percolated into the abdomen probably before death. The Hepatic Duct arises, by very delicate branches, from the Acini of the Liver. These branches are united into three or four trunks, in the transverse fis- sure, 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 Cho- ledochus. The biliary canals thus formed, are situ- ated in the right side of the Hepatico-gastric, or lesser Omentum, in what is commonly called the Capsule of Glisson. The Ductus Communis being three inches, or three and a half long, is to the right of the Vena 240 OF THE TRUNK. 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 men- tioned, 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 longitudinal 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 magnitude 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 mentioned as a medium size. Its transitions of magnitude are frequent and rapid in the same individual, depending on the stage of diges- tion, upon sickness, and probably on mental sensations. Several spleens sometimes exist in the same person. CONTENTS OF THE ABDOMEN. 241 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 sometimes 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 peritoneum, 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 processes just mentioned. The internal coat is a grayish, compact, extensible, elastic membrane, in close adherence with the external; it sends in processes to accompany the blood-vessels; and moreover from its internal face there proceeds a multitude of lamellas and of fibres, dividing its cavity into cells. It seems to be intended to sustain the natural shape of the spleen, and to sup- port its peculiar structure. The spleen is remarkably well furnished with blood- vessels. It derives a large artery from the coeliac, distinguished by its tortuous course, and by the branches which it furnishes to the stomach and pan- creas. 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 along the upper edge of the pancreas; it joins the Vena Portarum. 31 242 OF THE TRUNK. In the body of the spleen are found many grayish, soft, semi-transparent gelatinous corpuscles, from an almost imperceptible magnitude to a line or more in diameter. By Malpighi, they were considered glandu- lar ; and by Ruysch, as convoluted vessels. The mass of the spleen, upon a superficial examination, seems to consist in a bloody dark brown pulp, contained in the numerous cells of the internal coat. On this cellular struc- ture, the vessels pass. M. Assolont considers that blood, besides existing in the arteries and veins, is placed in a state of particular combination, and of intimate union with the other organic elements of the viscus, and with a large quantity of albumen; that this peculiar combi- nation of the blood forms the dark grumous fluid just mentioned, which may be easily seen by scraping the spleen with the handle of a scalpel. Of the latter, there can be no doubt; but a question 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, but M. Marjolin, denies it, on the following grounds. That injections, cautiously made, pass immediately from the 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 ramifications of the vessels distend- ed by the injected fluid, are distinctly seen. The pro- bability then is, that the peculiar structure of the spleen is formed essentially of arterial and venous capillary vessels, with very delicate and extensible coats, and CONTENTS OF THE ABDOMEN. 243 that they communicate with each other, without the intermedium of any cell; and that the extreme tenuity of these vessels, and their extensibility in every direc- tion, are sufficient to explain the augmentation of vol- ume which the spleen affords, under certain circum- stances, and the promptitude with which it diminishes under others. It has no duct. Of the Pancreas, {Pancreas?) This is an oblong conglomerate gland, extending across the spine, and fixed in the back and lower part of the epigastric region. It is connected to the spleen on the left, to the duodenum on the right, is behind the stomach and between the laminas of the transverse mesocolon. The Pancreas is of a light gray colour. It is about six or seven inches long and two wide; and 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 an- terior face is turned obliquely upwards and corresponds with the superior lamina of the mesocolon. The pos- terior face is obliquely downwards, has a long fossa in its upper part for the splenic vessels, and is in contact 244 OF THE TRUNK. with the aorta, vena cava ascendens, the superior me- senteric vessels, and several nerves. The pancreas has no peritoneal coat, excepting the mesocolon, neither has it a proper tunic, unless one should consider as such the lamina of condensed cellu- lar membrane which envelopes it, and which sends in processes between its lobules. The structure of the pancreas strongly resembles that of the salivary glands and consists of granuli, united into lobules, which form lobes whose interstices are occupied with numerous vessels. The excretory duct of the gland arises from these granulations, by very fine radicles which, uniting, form larger cylinders in- clining from left to right. These latter empty succes- sively into a long tube, the Ductus Wirsungii, going the whole length of the gland and situated near the very centre of its substance; it is small at the splenic extremity, but gradually increases till it becomes 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 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 de- rived from the splenic. The veins empty into the splenic. CONTENTS OF THE ABDOMEN. 245 Of the Kidneys, {Renes.) To get a good view of the kidneys, the other abdomi- nal viscera should be removed, or at least the intes- tines. The Kidneys are two glandular bodies for the secre- tion 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 lumbar, though the right, in consequence of the pressure of the liver from above, is lower down than the left. They are deposited in a large parcel of fat on the up- per part of the great psoas, the quadrati lumborum musclejs, and on the lower part of the great dia- phragm. The shape of the kidney is a compressed ovoid ex- cavated on one side like a bean. The broad end of the ovoid is above, and the excavation presents obliquely forwards and inwards. The latter has a deep fissure in it for the passage of the blood-vessels and excretory 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 pene- trates into its fissure. The capsule is there perforated with many foramina for trasmitting the blood-vessels. This membrane is fibrous, semi-transparent, and some- 246 OF THE TRUNK. what elastic ; it is easily peeled from the surface of the kidney, and in doing 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 subsequently unite, the vestige of this union is frequently preserved. The kidney being laid open longitudinally, we shall obtain an idea of its internal arrangement. It is seen obviously to consist of two parts of different appear- ance ; the external which, from its position, is called Cortical; and the Internal or Tubular. 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 ap- proaches the fissure; these terminate by penetrating to all parts of the gland in a crowd of arterioles, so that when they are injected with wax and corroded, the figure of the gland is preserved. Some of these mi- nute arterial branches terminate in corresponding veins, and others in the glandular structure of the organ. The Cortical part is the most vascular; it is, at an average, about two lines in depth, is made of granules called acini, and forms the periphery of the gland, but different portions of it project and form partial parti- tions between the tubular sections. It tears with facil- ity, with a granulated edge or surface, and its colour is a dark or reddish brown. When viewed with a microscope the granulations are distinctly seen of ex- treme minuteness, and receiving the capillary extremi- CONTENTS OF THE ABDOMEN. 247 ties of the arteries. I have more than once injected these granulations from the arteries, and observed the fluid coming through the ureter and the emulgent vein. The second or Tubular portion 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, and as mentioned, are partially separated from each other by processes from the cortical part; they are dense, of a lighter brown, and tear with facility in the course of the fibres. Each cpne is formed by a great number of very fine canals converging close to each other near the apex, and joining. They appear only to give passage to the urine, as cases have occurred, in which they were en- tirely removed by suppuration and ulceration. The technical name for these canals, is Tubuli Uriniferi; they begin in the cortical part of the kidney from the acini and pass through it in a serpentine course. The terminations of the cones are called Papillas, and an attempt has been made to establish for them some peculiarity of organization; but that idea is now aban- doned, 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. 248 OF THE TRUNK. Of the Excretory Ducts of the Kidneys. The excretory duct of the kidney begins in its cen- tre by a dilatation called Pelvis, branching into several divisions called Calices, each of which ends in three or more funnel shaped tubes named Infundibula. Each papilla has its appropriate infundibulum which adheres to and surrounds its base; but sometimes there are two of the former to but one of the latter. The excretory duct of the kidney has two coats, the external of which is fibrous and the internal mucous. The latter is said to be continued over the papillas, and may probably enter into the tubuli uriniferi. It enjoys a great degree of extensibility and contractility of tis- sue, and its sensibility not perceptible in health, is ex- quisite in disease. The Pelvis of the kidney is continued into the Ureter, a canal about the size of a writing quill, and which is in contact behind with the psoas magnus muscle, and the iliac and hypogastric vessels, crosses the vas de- ferens at the back part of the bladder, and passes ob- liquely through the coats of the latter, to end in an orifice a little behind that of the Urethra. The emulgent veins are parallel with the arteries, and terminate in the vena cava ascendens. CONTENTS OF THE ABDOMEN. 249 Of the Renal Capsules, {Capsular Renales.) They are two little triangular pyramidal bodies, one for each kidney and placed 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 then than in the adult; their structure also seems to be much changed in the latter. From being placed precisely on the upper ex- tremity of the kidney they have the lower surface which touches it of a corresponding concavity. On the exterior of this body is a proper coat formed of lamellated and condensed cellular tissue, which fur- nishes from its internal surface many prolongations di- viding the gland into lobes. These lobes are divisible into lobules, which again consist of a granulated struc- ture that seems susceptible of other divisions. These granulations are not firm and resisting. In the centre of the Capsula Renalis, frequently there is a triangular cavity which may be demonstrated by thrusting a tube into it, and inflating, or by an in- cision. In the foetus this cavity contains a reddish viscid fluid coaguiable by alcohol: in children it be- comes yellow: in adults it is dark brown, and in old people it is either wanting or in a remarkably small quantity. The arteries of these bodies come from the emul- 32 250 OF THE TRUNK. 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 the abdominal cavity; it is ex- tremely concave below and convex above, the con- cavity being occupied by several of the abdominal viscera. To view it properly, all the abdominal vis- cera 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 varied structure of this important organ, and the dissector, while performing it, is continually liable to the accident of a puncture being made through it into the thorax; in which case the diaphragm loses its concavity, and becoming flabby and displaced, the value and beauty of the display are much impaired. The dissection being properly achieved, exhibits a broad concave muscle connected with the inferior margin of the thorax on all sides, and having for its DIAPHRAGM. 251 centre a silvery tendon resembling in its outline the heart of a playing card. This cordiform tendon oc- cupies 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 dia- phragm is inserted all around its circumference. The cordiform tendon is nearly horizontal in the erect pos- ture, 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, {Foramen cesophageum) is in the back of the muscle between the spine and the notch of the cordi- form tendon, a little to the left. It gives passage to the oesophagus and the par vagum nerves as connected with it, and is rather a fissure or a long elliptical fora- men made by the separation and reunion of the mus- cular 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 ten- don, is a very large and patulous foramen, {Foramen quadratum) for the ascending vena cava. It is between an irregular quadrilateral figure and a circle; its edges 252 OF THE TRUNK. are composed of fasciculi of tendon rounded off, and are not susceptible of displacement, or of alteration in their relative position to each other, by which means is obviated 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 oeso- phagus, is the third hole {Hiatus aorticus) in the dia- phragm, which affords passage to the aorta. It is just in front of the bodies of the three upper lumbar vertebras, and is a much longer elliptical hole than the oesophageal; 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, in the vertical posture, descend lower than the other. Thus circumstanced, the Diaphragm arises fleshy, from the internal face of the upper edge of the Xiphoid Cartilage, from the internal face of the cartilages of the seventh true, and of the succeeding false ribs, on each side. That is, from the cartilages of the eighth and ninth, from the osseous extremities of the tenth and eleventh, and from both the osseous and cartilagi- DIAPHRAGM. 253 nous 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 pro- trusion into the Thorax. It is probable that greater displacements of the abdominal viscera, into the thorax of adults or children, may have had a congenital origin in this very fissure, and are subsequently, when the parts are modified to this unnatural situation, set down as a Lusus Naturas. The part described in this paragraph is called the greater muscle of the Diaphragm. Besides these origins, the Diaphragm has several from the vertebras 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 prevented from being very distinct in its origin, in consequence of running into the ligament in front of the bodies of all the vertebras. The second pair of heads is on the outside of the first, and arises tendinous from the Intervertebral ligament, between the second and third vertebras. The third pair of heads arises tendinous from the upper part of the lateral margins 254 OF THE TRUNK. of the second lumbar vertebra. And the fourth pair of heads comes also tendinous from the fore part of the roots of the transverse processes 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 between 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, the diaphragm is connected with the transversalis abdo- minis. 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 hav- ing a tendency to become straight by contracting, will * 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 do much better to say that it arises tendinous, from the first, second, and third vertebrae. The heads are occasionally much small- er on one side than the other. PSOAS MAGNUS. 255 descend, and thereby enlarge the thorax. It is not certain that the cordiform tendon descends, its connex- ions being too strong and numerous to admit of much motion. In expiration, the relaxation of the Dia- phragm, with the contraction of the abdominal muscles, restores the former to its first state. In vomiting, the Diaphragm and abdominal muscles concur to expel the contents of the stomach. The Psoas Magnus muscle arises, fleshy, from the side of the bodies of the last dorsal and of the four upper lumbar vertebras, and from the transverse pro- cesses of all the lumbar vertebras. It forms an oblong fleshy cushion on the side of the lumbar vertebrae, and, constituting the lateral boundary of the inlet to the pel- vis, it passes out of the pelvis, under Poupart'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 Psoas Parvus, arises, fleshy, from the contigu- ous edges of the last dorsal and of the first lumbar verte- bra at their sides, and from the intervertebral ligament. It is at the anterior and internal edge of the psoas mag- nus ; has a short belly, and a long tendon by which it is inserted into the linea innominata, about half-way be- tween the spine of the pubes and the junction of this 256 OF THE TRUNK, bone with the ilium. The tendon, besides, 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 liability to injury from their too great or sudden flexion. This muscle is sometimes wanting. 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 last lumbar vertebra, from the inner margin of the crista of the ilium, and from its whole concavity; also 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 near this pro- cess. 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 Quadratus Lumborum is an oblong muscle passing from the superior back part of the spine of the ilium, by a tendinous and fleshy origin of two or three inches in length. It lies at the side of the lumbar ver- tebras, into all the transverse processes of which it is inserted by short tendinous slips. It is also inserted QUADRATUS LUMBORUM. 257 into the lower edge of the last rib near 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. 33 PART II. CHAPTER II. OF THE MALE PELVIS. The first step of the student, after a short examina- tion in situ of the contents of the pelvis, should be to detach the penis from its bony connexions and to re- move it, with the bladder and rectum, from the pelvis. Then to make a fair and clean dissection of these organs by detaching the surrounding fat, cellular mem- brane and muscles. This dissection is best made with the scissors, and its utility is in proportion to its clean- ness; the latter is much assisted by inflating the blad- der and by stuffing the rectum. The scrotum may be separated and laid aside for future examination. SECTION I. Of the Viscera of the Male Pelvis. The Rectum, being the termination of the colon, be- gins at the left sacro-iliac symphysis; from thence it MALE PELVIS. 259 passes down obliquely towards the middle of the sa- crum about one half of its length; its course afterwards is directly downwards before the sacrum and os coc- cygis till it terminates in the anus; its orifice there points backwards and downwards. It is round till just before its termination, it then dilates 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 vesiculas seminales and the prostate gland. Posteriorly and above, it is confined to the sacrum by the mesorectum, which conducts its nerves and blood-vessels. The dip of the peri- toneum between the vesiculas seminales so as almost 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. Many of the longitudinal fibres on getting to its infe- rior margin pass beneath it and are then turned upwards so as to be inserted into the mucous coat. The mucous membrane of the gut is smooth above, but at the lower part it is thrown into several longitudinal folds called 260 OF THE TRUNK. the Columns of the rectum, at the lower end of which are some small blind pouches looking upwards; its mu- cous lacunas are numerous. The anus is thrown into radiated folds from the influence of the external sphincter ani. The Bladder, (Vesica Urinaria,) is fixed just behind the symphysis of the pubes and when pressed upon by the neighbouring viscera, is somewhat flattened before and behind; but removed from the body and distended, it resembles an elongated sphere, of which the greatest diameter is vertical in regard to the linea ilio-pectinea. The technical name for each end of the sphere is Fun- dus, distinguished by the terms upper and lower, the lower being somewhat the more obtuse. From the upper end proceeds to the navel a long conical liga- ment, the Urachus. By putting the anterior parietes of the abdomen on the stretch we shall see starting out and protruding the peritoneum into a semilunar duplicature on each side of the urachus, the remains of the umbilical arteries of the foetus which now are called the Round Ligaments of the bladder, though they have but little or no influence on it. At the anterior part of the lower fundus, the bladder is somewhat elon- gated into a process called its Neck, resembling a truncated cone, and being the commencement of the urethra. The bladder consists of four tunics; the Peritoneal, Muscular, Cellular, and Mucous. MALE PELVIS. 261 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 mus- cular coat by very loose cellular membrane, which pre- vents it from participating in any considerable disten- tions 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 pubes. Tapping the bladder 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 varied directions, 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 ob- lique fibres uniting these together, but still leaving interstices through which the internal coat occasionally protrudes, and thus forms cells in the cavity of the bladder. There is an accumulation of fibres about the neck of the bladder and the urachus, which gives an increased thickness at these points. The Cellular coat consists of a close, dense, lamel- lated, and filamentous tissue, highly extensible and dif- 262 OF THE TRUNK. ficult to tear. It is impervious to water, closely adherent 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 between the orifice of the urethra and those of the ureters, (the Trigone Vesicale of the French,) which is elevated into a plain smooth surface. Mr. Charles Bell thinks the lateral margins have muscular fibres beneath, in- tended to regulate the orifices of the ureters.* 2. The Uvula Vesicas, a small pointed production terminating the triangle 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. 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 * My personal investigations on this point have not verified the assertion. MALE PELVIS. 263 and the posterior side of the bladder. 5. The Inter- nal Orifice of the neck of the bladder, resembling somewhat the neck of a Florence flask. The Neck of the Bladder is thicker than any other f 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. It has a sphincter muscle formed in the following way which may be seen by removing the lining membrane. A transverse fasciculus crosses its inferior semi-circumference from one lateral lobe of the prostate gland to the other; this fasciculus is half an inch wide and from one to two lines thick, and is placed over the third lobe of the prostate. The superior semi-circumference is also crossed by a thin layer of muscular fibres, which spreads itself out at the ends where it is lost in the ordinary muscular structure which it resembles exactly. Under the mucous membrane corresponding with the vesical triangle there is a muscle of the same shape and dimensions, the posterior corners being inserted around the orifices of the ureters, and the anterior being attached to the caput gallinaginis. Prostate Gland, {Glandula Parastata.) This is a body about the size and form of a horse chestnut, fixed as stated on the neck of the bladder, 264 OF THE TRUNK. and penetrated 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 inferior surface rests upon the rectum, and its sides, in the distentions of this organ by fasces, are overlapped by it. The Prostate has, posteriorly, a notch in its centre, which divides it into two lateral lobes, and by raising the Vesiculas Seminales, we shall see where their excretory ducts penetrate the gland, and separate from the body of it the little tubercle, called the Third Lobe. The organization of this body, seems to consist in a condensed, white, extensible, though easily lacerated fibro-cellular tissue, and within it are placed a great number of mucous follicles, which form from eight to twelve ducts,* passing obliquely forwards, and termi- nating in the urethra at the sides 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 capsule, of which more hereafter.t The Seminal Vesicles, (Vesiculas Seminales,) are two convoluted bodies of two inches in length, one on * Loder says there are from thirty-two to fourty-four. t An opinion prevails among the anatomists of Philadelphia, that the prostate is larger in the African than in whites. Indeed this much may be said of all the organs of generation in both sexes. MALE PELVIS. 265 each side of the lower fundus of the bladder, approach- ing each other very nearly at the base of the Prostate, but diverging much as they recede. They are sepa- rated 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 cellular tex- ture, having many large veins pervading it. When inflated and dried, they present the semblance of cells, but are in fact long tubes, which, by being convoluted, are reduced to the apparent dimensions mentioned : there are also several pouches on each side of this long tube which increase the number 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 continuation of the lining membrane of the bladder. They are commonly filled by a drab-coloured thick fluid, supposed to be a mix- ture of the semen, and of their own proper secretion, though, of this, Mr. Hunter doubted.* The excretory duct of each vesicle is about a line and a half long, when it 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, below the urethra. The Ductus Ejaculatorius, is about eight or ten * See Observations on the Animal (Economy. 34 266 OF THE TRUNK. lines long, and opens by an oblong orifice, at the late- ral anterior face of the Caput Gallinaginis; it is larger behind than before, which gives it a conical shape, and allows fluids injected to pass freely from the vas defe- rens to the vesicula, or the reverse. Of the Penis, {Membrum Virile, Mentula.) It is a membranous and cellular body affixed to the margin of the pelvis, at and below the symphysis pubis, and appropriated to the passing 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 fur- nished with a considerable number of sebaceous follicles, more particularly about the root of the organ. It is very loosely connected by cellular membrane to the parts beneath, so that it is easily made to correspond with all states of the penis. At the anterior extremity it is arranged into a duplicature or fold, the Preputium, which is inserted just behind the glans; the inferior part of the prepuce is connected with the extremity of the glans by a process called Frasnum. The penis, besides arising from the bones of the pelvis in a manner which will be presently explained, is fixed to the symphysis pubis by a ligament, (Liga- MALE PELVIS. 267 mentum Suspensorium,) which is a triangular fibrous body, flattened laterally and lost insensibly on the fascia of the thigh covering the adductor muscles. The portion of it which goes to 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 ex- tended over the penis, and according to Mr. Colles constitutes one of its coverings, by going as far as the glans. Professor Marjolin says that he has seen on seve- ral occasions muscular fibres entering into its composi- tion, and in that case it draws the organ with more force towards 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 de- gree of contractility; its fibres pass 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 oc- casionally called its elastic ligament. It arises by two conical crura, one from the internal face of the crus of each pubes and ischium, to within a little distance of the anterior part of the tuber ischii. At the lower part of the symphysis pubis these crura join and form a body, which, when stripped of its connexions, resem- bles two cylinders lying along side of each other and * I have seen it in one case, February 11th, 1825. 268 OF THE TRUNK. united ; anteriorly they terminate in common by a trun- cated cone covered obliquely by the glans. At the posterior part of the corpus cavernosum, in its centre, there is a tolerably complete septum of the same kind of substance, separating its two halves from each other, but anteriorly this septum is imperfect, having an arrangement like the teeth of a comb, whence the term Septum Pectiniforme. In the middle of the corpus cavernosum above, is a longitudinal sulcus for lodging the veins of the penis, and in the same nianner below, another for the corpus spongiosum urethras. The cavity of this membrane is filled by a spongy tissue, which arises from its inter- nal face, and is formed of filaments and little laminas; they, by crossing each other, form a multitude of cells which have a perfectly free communication with each other, and generally are somewhat occupied by blood. The Corpus Spongiosum Urethras 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 resembling that of the corpus cavernosum, except that it is thinner. In its centre is the canal for the urine. Between this canal and the coat is a spongy structure, much finer than that of the corpus cavernosum, 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 MALE PELVIS. 269 what is termed its Bulb; from this it diminishes gradu- ally to the end of the corpus cavernosum, where it is again enlarged 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 surface of the glans is covered by thin skin making a very delicate epithelium, and a great number of papillas for. the termination of nerves. Numerous follicles also exist about the corona glandis, to secrete the sebaceous fluid which collects there in persons who are not cleanly. They constitute the glands of Tyson. The Urethra is a canal whose length varies accord- ing 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 lacunas of its internal membrane. The first part of this canal which traver- ses the prostate gland is about fifteen or eighteen lines in length; it is the Prostatic Portion, and is well sup- ported by this body, although its own sides are very thin. On its inferior surface is the Verumontanum or Caput Gallinaginis, an oblong projection of the lining membrane an inch in length, broad behind where it commences a little in advance of the Uvula Vesicas, and coming to a point very gradually before. In the pos- terior ridge of the caput is a long cleft, which is the orifice of a lacuna observed first by Morgagni; and 270 OF THE TRUNK. on the front surface on each side, is the orifice of the ductus ejaculatorius. On the sides of the caput gal- linaginis the canal of the urethra is depressed into something like a cul-de-sac, where are to be found the orifices belonging to the lacunas of the prostate gland as stated. Between the Prostate and the Bulb is the Mem- branous 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 considered by Littre as a glandular body which secreted a viscid humour into the interior of the canal; the latter pro- bably is the part described by Winslow as the inferior prostatic muscle, which arising on each side of the membranous canal, goes to be inserted into the corres- ponding branch of the pubes 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 crura of the Corpus Cavernosum. The canal varies in its dimensions; at its commence- ment at the bladder it is large; it then contracts at the back of the caput gallinaginis, and immediately enlarges in the fore part of the prostate at the sides of the urethral crest. The membranous part is small; the canal then enlarges in the bulb. In the body of the penis the " canal is successively diminished, till it comes almost to MALE PELVIS. 271 the glans, when it is so remarkably enlarged as to get the name of Fossa Navicularis; it terminates finally 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, excepting the fossa navicularis longitudinal folds of the lining mem- brane exist which are effaced by distention. In the upper part of the canal there are a great many mucous lacunas; Loder, in his plates, has marked about sixty- five; there is one particularly large in the upper sur- face 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 membrane 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 exist occasionally; they are placed just before Couper's and are called the glands of Littre. Mr. Shaw of London has described a set of vessels * 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 observations, he is induced to think, that there can be no doubt of its muscularity. 272 OF THE TRUNK. 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, being ja. quicksilver injection of the part, is certainly a very satisfactory demonstration of their existence: yet in my own observations, I have not been able to distin- guish them from the cellular membrane connecting the canal of the urethra to the corpus spongiosum. Of the Testicles, {Testes.) These bodies, two in number, are surrounded by several coats, the most external of which, is common to both the testicles and is called Scrotum; the others are proper. The scrotum is a sac formed by a con- tinuation of skin from the internal sides of the thighs, from the inferior part of the penis, and from the ante- rior 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 extensi- ble, and has a great power of contraction, its surface being covered with wrinkles which are more apparent when it is contracted. It consists of two symmetrical MALE PELVIS. 273 halves marked off from each other by an elevation of skin, the Raphe, which extends from the perineujn over the scrotum along the inferior 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 ischia and pubes, and passing downwards, it joins the raphe; it is then reflected upwards, forms a septum be- tween the two sides of the scrotum, and goes up to the inferior part of the urethra. This membrane has been confounded with cellular substance; but it ap- pears from the reports of Messieurs Chaussier, Lob- stein, and Breschet, that it does not exist in the scrotum till the descent of the testicle, and that it is an expansion of the gubernaculum testis. Notwithstanding its great contractility, the question of its muscular structure is not settled, and certainly, in the greater part of its extent, there is not the ap- pearance of muscular fibre, but at its posterior end, 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. Tho con- tractility of the scrotum has been attributed to the cremaster muscle instead of this membrane, but com- mon observation will convince most persons that the elevation of the testicles in the scrotum by the contrac- tion of the cremasters is very distinguishable from that contraction of the scrotum by which the testicles are 35 274 OF THE TRUNK. squeezed against the sides of the pubes 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; they lay on its front part, and on the internal and external sides of the spermatic chord. Within the last is a coat of cellular substance the Tunica Vaginalis Communis. The Tunica Vaginalis Testis was originally a pro- cess of peritoneum, though it appears in the adult as a complete sac. The testicle being protruded into it from behind, one half of the sac applies itself closely to the epididymis and testicle, while the other half is loose; the whole arrangement being precisely after the manner of a double night-cap when drawn over the head. It passes up some distance on the chord; its cavity is smooth, polished and moistened by a synovial halitus which allows the surfaces to move freely upon each other. 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 par- tial partitions pass off, and terminate at the posterior part of the cavity in the Corpus Highmorianum. These MALE PELVIS. 275 septulas conduct the blood-vessels through the sub- stance 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 efferentia. The form of the Testicles as communicated by the tunica albuginea, is very much that of an oval, some- what compressed laterally, the edges presenting for- wards and backwards; they do not hang with the 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 is larger; it is also higher up than the left, a circumstance which has been marked by sculptors in all ages. The glandular structure of the testicle consists of a congeries of convoluted tubes, stated by Monro to amount to three hundred, whose diameters do not ex- ceed individually the one two-hundreth part of an inch, and when extended to their full length, would form in the aggregate, 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 exceeding difficulty, and scarcely ever succeeds fully. Such preparations are consequently very rare in anatomical cabinets. The Tubuli Seminiferi, it has been stated, fill up 276 OF THE TRUNK. nearly the whole of the cavity of the albuginea, being kept from each other by the processes termed Septulas. These tubes send out a great number of trunks, which, from their observing a straight course, obtain the name of Vasa Recta. These vasa recta unite near the centre of the testicle, 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 externally at this place, so as to give the outline of a cone, therefore, it gets the name of Conus Vasculosus. Each cone suc- cessively empties into a single tube on the back of the testis, which is prodigiously convoluted and forms a large body, the Epididymis. The Epididymis is a prismatic arch enlarged at both extremities, and resting vertically on the back of the testicle, being connected with it by the tunica vaginalis. The enlargement above is the Globus Major, and is formed of the coni vasculosi, but what remains of this body below, consists of one tube excessively convo- luted. The enlargement below 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 MALE PELVIS. 277 commences at the top of the epididymis and terminates below, the intention of which is not known.* The Vas Deferens is a white tube about a half line in diameter, having a cartilaginous feel; its cavity is large enough to admit a bristle. It passes on the back of the spermatic chord, and continues with it through the abdominal canal; at the internal ring it leaves the residue of the chord, and dipping into the pelvis by the side of the bladder, goes between it and the ureter to the lower fundus, approaching its fellow on the inside of the vesiculas seminales, and ending in the urethra, by the Ductus Ejaculatorius. About two and a half inches from its termination it becomes somewhat tor- tuous and enlarges. The Spermatic Chord is formed of the Vas Deferens, the Spermatic Artery and Veins, Lymphatics, Nerves, and Cellular membrane, all covered by the Cremaster muscle. The artery arises from the aorta and retains its first 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 terminat- ing on the tubes. The veins in ascending form a re- markable plexus, the Corpus Pampiniforme, at the internal ring they unite into one trunk, which on the right joins the ascending cava, and on the left the emulgent vein. * It is sometimes called the Vasculum Aberrans Halleri, and is said by Mr. Cruikshank, to be an analomy. 278 OF THE TRUNK. 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 reconi- mended for Lithotomy, in order that he may work on the Perineum. SECTION II. Of the Perineum and the Fasciae, of the Male Pelvis. The subject being fixed in the posture indicated, make a horizontal cut through the skin, at the junction of the raphe of the perineum with the scrotum, extend- ing it on each side three inches, make another trans- verse cut of the same length over the end of the os coccygis; drop a perpendicular cut equally profound with the first from its middle to the point of the os coc- cygis. The skin constituting the flap on each side being raised up carefully, so as not to injure subjacent parts, when the two flaps are pinned aside the structure of the perineum is sufficiently opened for the time. The Perineal Fascia is first exposed; it occupies nearly all the space between the anus and the poste- rior margin of the scrotum, (insensibly blending with the latter,) and between the rami of the pubes and of the ischia, being very firmly fixed to these bones. This MALE PELVIS. 279 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 abscesses of the perineum, it also prevents the fluctuation from being very'evident. Hav- ing studied well its connexions, structure and influence, it is to be raised up and turned to each side by a cut down its middle in order to bring into view the Peri- neal 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 inter- nal and external margins of the rami of the pubes and ischium, proceed upwards, and, just before the union of the crura of the penis, end 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 Urinas lies on the bulb and back part of the corpus spongiosum urethras; 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 * The late Dr. Lawrence informed me that he has frequently found muscular fibres between the bone and the crus penis. 280 - OF THE TRUNK. across the inferior surface of the crus where the latter begins to form the body of the penis. It arises also from the inner side of the ramus of the pubes between the crus penis and the triangular ligament of the ure- thra. The muscles of the opposite sides are inserted into each other by a white line which marks the mid- dle 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 dis- tinctly, separate them from each other in the middle line and dissect them from the corpus spongiosum. Cut transversely through the corpus spongiosum about three inches before the triangular ligament and dissect it clearly from the corpus cavernosum, turning it down- wards so that it may hang by the membranous part of the urethra. By putting the two acceleratores on the stretch it will be seen that, besides the origins men- tioned, they arise also from each other by a tendinous membrane that is interposed between the corpus spon- giosum and cavernosum, so that they literally surround the posterior part of the urethra constituting a com- plete sphincter muscle for it. These two muscles are considered by M. Chaussier as forming but one; in that case its origin will be re- versed, and commence in the middle line of the peri- neum instead of terminating there. The relation of this muscle and the erector penis should be observed,' in order to appreciate the difficulty of getting into the MALE PELVIS. 281 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 the accelatores join. I have observed that, when the lower part of the accelerator was extended much below its usual line and strongly developed, the transversus was very irre- gular in its origin and course, consisting frequently of a few fibres which did not deserve the name of a dis- tinct muscle, and were 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 first and is inserted into the peri- neal 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 os coccygis behind and the perineal union of the other muscles in front; its lateral diameter occupies about 36 282 OF THE TRUNK. one-half of the space between the tuberosities of the ischia, as it is in the midddle of this] space. The point of it in front is continued into the dartos. 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 interior of the pelvis, but is seen well enough here. It arises by a small, tendinous, and fleshy beginning from the spine of the ischium, and, lying on the anterior face of the anterior sacro-sciatic ligament, it is inserted into the side of the last bone of the sacrum and into all those of the os coccygis. It draws the os coccygis forwards. The Erectores Penis, Acceleratores Urinas, and Transversi Perinei are now to be removed. A large quantity of adipose and cellular matter will be found on each side of the rectum between it and the parietes of the pelvis, concealing the levatores ani muscles. This fat is better left in situ for the present. The muscles being removed, the bulb of the urethra is seen to great advantage, extending in the middle of the perineum almost to the anus. It is not loose and pendulous as described, but is connected by its supe- rior face to the Triangular Ligament of the urethra, a membrane which fills up the space below the sym- physis of the pubes. This ligament is a septum be- MALE PELVIS. 283 tween the perineum and pelvis, and, when closely ex- amined, is seen to connect itself to the internal edges of the rami of the pubes and ischia at the inner poste- rior sides of the crura penis as far down as the begin- ning of the latter. At its lower edge its ligamentous character is not so well defined. It extends from the top of the pubic arch downwards an inch and a half, filling up all the intermediate space between the bones. On its anterior surface is the bulb of the urethra, and just at the extremity of the latter, enclosed by the liga- ment and adhering to it, are Couper's Glands. A perforation exists in it through which passes the mem- branous part of the urethra; to get a view of which the corpus spongiosum if not already detached 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 being continued a little distance on the canal, but by detach- ing 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 con- siderable angle with each other, and the membranous part of the urethra is much the deeper; the recollec- tion of which is all important in lithotomy, as it teaches us to avoid the one, and to cut into the other. It will 284 OF THE TRUNK. also be observed that the hole in the triangular ligament is an inch below 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 pubes 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 pubes.* The breadth of this having been stated at half an inch, it is obvious that the hole in the triangular ligament is half an inch below the lower edge of the interpubic. We ha.ve now seen as much as can be viewed advan- tageously 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 ilium 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 * See Abdominal Muscles. MALE PELVIS. 285 Levatores Ani muscles. Care must be taken not to injure the rectum in these sections. Begin by raising the peritoneum from the anterior surface of the rectum, after which by letting the rectum 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 bladder at the posterior end of the vesiculas siminales, but that a. pouch or process of it is sent down between them which reaches to a short distance from the prostate gland, and that below this process of the peritoneum, a very small space of the bladder lies naked which can be punctured from the rectum, without in- juring either the cavity of the peritoneum or the vesiculas seminales. The upper margin of this pouch next to the bladder forms a strong horizontal doubling stretching across the pelvis, when the rectum is empty. By distending the bladder moderately, the different reflections of the peritoneum from it to the abdominal parietes and to those of the pelvis will be better under- stood, and the possibility of puncturing the former above the pubes 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 286 OF THE TRUNK. connecting the bladder to the sides of the pelvis. "This fascia descends from the ilio-pectineal line to about midway in the depth of the pelvis; here it is re- flected from the surface of the muscles (the Levatores Ani) and applies itself to the prostate gland and blad- der, on the body of which it is ultimately lost. At the angle of its reflection this fascia 'appears particu- larly 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 pubes just below the symphysis, a pointed production of it constituting its anterior margin is fixed into the side of the neck of the bladder. This pointed produc- tion on each side is called by most anatomists the Anterior Ligament of the bladder. Between the two just beneath the symphysis of the pubes a pouch large enough to receive the end of the finger is formed by the union of the fascias of the two sides; this pouch connects the middle anterior part of the neck of the bladder to the lower margin of the symphysis pubis." A good account of this fascia is published by M. Breschet.* He says, " that when the aponeurosis which covers the iliac fossa arrives at the internal margin of the iliacus internus and psoas magnus mus- cles, near the superior strait of the pelvis, it plunges *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. MALE PELVIS. 287 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 reflected upon the bas-fond of the bladder, the prostate gland, and in woman upon the vagina. From which cause these viscera may be said to be in part In the cav- ity 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 differ- ent 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. Some distinguished practitioners* have asked the reason of these differences, and I believe that I have found them in the arrangement of, the apo- neurosis 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 developes itself, suppuration takes place beyond this aponeurotic bar- rier, 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, ■*■" Scarpa's Memoir on Hawkins' Gorget. 288 OF THE TRUNK. but rather too general; the most common condition of it is found to be as follows. It adheres closely to the periosteum of the pubes between the upper mar- gin of the thyroid foramen and the crista of the pubes; about the middle third of the linea innominata it is obviously a continuous membrane with the iliac fascia, but behind this again it arises from the remaining 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 pubes above the foramen thyroi- deum, and the other end to the ischium above its spine. The perineal surface of this bow is an impor- tant point of the origin of the levator ani. Above the bow this fascia is very thin, for the fibres of the obtu- rator internus can be readily seen through it. At the bow this fascia divides into two laminas, one having the course to the bladder and rectum indicated, the other covers the lower part of the obturator inter- nus muscle and constitutes the obturator fascia. The levator ani is interposed between the laminas. 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 MALE PELVIS. 289 inch above the middle of the fascia. As the muscle is placed nearer to the perineum, the fascia must be turn- ed 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, particular- ly at its posterior part from the under or perineal sur- face of the fascia. The Levator Ani muscle arises fleshy from the back of the pubes near its symphysis, and from near the su- perior margin of the foramen thyroideum above the obturator internus muscle. It also arises from the aponeurosis pelvica, where this membrane is extended as a thickened semilunar chord from the superior margin of the thyroid foramen to the spinous process of the ischium. This second part of the origin of the leva- tor ani is defectively described in most books on ana- tomy. It is then seen to cross obliquely, 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, de- scend backwards, and have three distinct places of in- sertion; 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 longitudinal fibres and the circular fibres of the sphincter ani; and finally, the most anterior fibres pass obliquely 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, 37 290 OF THE TRUNK. and are inserted into the common point of the peri- neal muscles. These insertions of the levatores ani, to be well understood, must be studied both from the perineal and abdominal surfaces. It yet remains to speak more definitively of the Tri- angular Ligament; it has been seen from the perineum, and is now to be viewed from the pelvis. Remove 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 ischia. Its base or inferior edge is crescentic; and half an inch above the base, is the hole for the membranous part of the urethra. 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 ligamentous 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 pubic arch, are continuous with the fascia covering the obturator internus muscle. The triangu- lar ligament is a membrane consisting of two lamina?; the bulb of the urethra is fastened to the anterior la- mina, and the prostate is fixed to the posterior lamina; between these laminas above, is the interpubic ligament, aud several blood-vessels derived from the vena ipsius penis. Mr. Colles says: " if we attempt, in conformity to the MALE PELVIS. 291 custom of anatomical writers, to describe all these con- tinuous fascias which connect the bladder and urethra to the pubes, as productions of one and the same fascia, we might say that the triangular ligament, by its outer edges, is fixed into the rami of the pubes and is there continuous with the ligament lining the obturator mus- cles, that the edge of the opening for receiving the membranous portion of the urethra is produced back- ward along the prostate, and having ascended as high as the arch of the pubes, it there splits into two lami- nas, one continuing its course over the upper surface of the gland and bladder, the other lining the upper por- tion of the levator ani." The description of the fascias of the pelvis is one of the most difficult and perplexing in the whole range of anatomy, and the proof of it is, that almost every wri- ter on the subject considers the labours of his prede- cessors imperfect, and, with a very laudable spirit, ho- ping to supply the defect, invites the attention of the profession to his improved views. Not joining in this conviction, of the insufficiency of preceding descrip- tions, and the consequent value of such as are offered as substitutes, I feel satisfied in drawing materials from Mr. Colles's excellent work on Surgical Anatomy. PART II. CHAPTER IV. OF THE ORGANS IN THE FEMALE FOR THE GENERA- TION AND NOURISHMENT OF THE INFANT. SECTION I. Of the Female Pelvis. The viscera of the female pelvis should be first stud- ied in their natural situations ; they should then be re- moved and dissected neatly for more satisfactory ex- amination. The whole study may afterwards be con- cluded 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 si- tuated between them, and consist of the Vulva exter- FEMALE PELVIS. 293 nally, of the Vagina in the middle, and of the Uterus with its appendages internally. Under the term Vulva we consider the Mons Vene- ris, the Labia Majora or Externa, the Labia Minora or Interna, the Clitoris, the Vestibulum, the orifice of the Urethra, the Fourchette, and the Fossa Navicularis. Of the Vulva. 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 corpu- lent 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 seba- ceous glands. The Labia Externa are oblong eminences, continued downwards and backwards, one on each side, from the mons veneris, and unite with each other by the fourchette at the anterior part of the perineum. They are produced in the same way with the mons veneris by a deposit of adipose matter beneath the skin or integuments; they are broader and more prominent above than below. On the side which looks to the thighs they are formed by the common skin, furnished sparingly with hairs; but on the internal face the in- tegument is a mucous membrane, being a continuation 294 OF THE TRUNK. of that of the vagina. These bodies have many seba- ceous glands externally, and mucous orifices internally on them. In their interior structure much cellular membrane, 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 longi- tudinal rima about twice the length of the orifice of the vagina for favouring still more the expulsion of the foetus. It is the Fissura Vulvas of authors. The Clitoris is a small body situated between the upper extremities of the labia externa on the lower part of the symphysis pubis, and corresponding with the male penis. It is furnished with a suspensory liga- ment, and curved towards the urethra. It consists of a body and of two crura; the body is about an inch long, and the crura being of the same length, arise from the internal faces of the crura of the pubes. It is covered by an elastic ligamentous membrane; has an internal spongy body capable of erection like the penis, divided by a septum pectiniforme, and having a similar supply of blood-vessels and of nerves. It has also an erector clitoridis muscle lying upon each 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 projects into the upper part of the bottom of the rima, and is called its Glans, but does not resemble, in structure, the glans penis. A kind of hood is thrown over it By a FEMALE PELVIS. 295 duplicature of the integuments of the part, which giving some resemblance to the penis, it is therefore called the Prepuce, (Preputium.) This prepuce is occasion- ally much elongated and its orifice constricted, so that the secretion from its cryptas is imperfectly discharged and produces much itching and irritation. Mr. Mar- jolin relates the case of a Spanish girl of four years, in whom he performed circumcision successfully, in order to free her of a very bad habit to which she was ad- dicted in consequence of this disease. The Labia Interna, or Nymphs, are two membra- nous productions passing downwards, one from each side of the prepuce. They arise from the internal sides of the labia majora, are seldom so broad naturally as to project beyond them, and, are wider in the middle than elsewhere; they terminate insensibly about half- way down the orifice of the vagina. They consist of a duplicature of the mucous membrane of the part, be- tween the laminas of which is placed a vascular cellu- lar membrane giving to them, when excited, a some- what erected condition. * In young subjects their vas- cularity communicates a vermilion 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 are intended to facilitate the enlargement of the vulva. 296 OF THE TRUNK. The Vestibulum is the depression at the upper part of the rima, bounded by the clitoris above and the nymphas laterally; in it are manjr mucous follicles^ At the inferior part of the vestibulum^about an inch below the glans clitoridis, is the Orifice of the Urethra, (Orificium Urethras.) It is generally marked by a slight rising or tubercle which is easily distinguished by the sensation of touch alone; its margin is often bounded 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 down- wards and forwards from the neck of the bladder; pass- ing under the symphysis of the pubis, and being 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 bladder; is thrown into several longitudinal folds, and has many mucous folli- cles in it. The external coat of the urethra consists of condensed laminated cellular membrane, forming a cylindrical body of half an inch in its transverse dia- meter, which has given the idea of the existence of a prostate gland in the female-. The lower and lateral surfaces of this cylinder are in contact with the vagina forming a protuberance into its cavity, and the upper surface is firmly connected to the triangular ligament of the pubes. The Fourchette, or Frenulum Vulvae, is situated FEMALE PELVIS. 297 at the inferior junction of the labia externa; it is a nar- row duplicature of skin extending across the vulva from one §jde to the other, and is, most frequently ruptured at the first parturition and disappears. That portion of the rima, betwixt it and the orifice of the urethra, is called, by many anatomists, the Fossa Navicularis. Of the Vagina. The Vagina is the intermediate part of the sexual or- gans, and extends from the Vulva to the Uterus, being placed between the Bladder and Rectum, and com- pressed 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 mem- brane 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 commonly 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 cir- cular membrane having a hole in the centre. It is generally so weak that it is ruptured at the first act of copulation, but occasionally so resisting that it has re- quired artificial division to make it yield even to the 38 298 OF THE TRUNK. expulsive efforts of the uterus in parturition. Its pre- sence then is not invariably a proof of virginity, nor is its absence a proof of improper indulgence. The vagina is a membranous canal o£, from four to six inches in length, differing according to age and pregnancy, being much shorter in women who have borne children, than in virgins. Its shape varies some- what, 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 pres- sure between the bladder and the rectum. It is shorter before than behind, corresponding in this respect with the pelvis by which it is influenced, and also in conse- quence of being attached to the uterus higher up on the sacral than on the pubic side. The peritoneum, in descending from the uterus an- teriorly, touches the top of the vagina for a little dis- tance, and is then reflected to the bladder, but poste- riorly, 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 connexion to the rectum is by rather loose cellular 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 con- densed cellular membrane, its fibres not passing in any FEMALE PELVIS. 299 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 Vaginas,) 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 circum- ference of the vagina. The structure of this body closely resembles that of the corpus spongiosum ure- thras, and from being very vascular, is subject to dis- tention in its cells during sexual excitement. This body is covered by the sphincter vaginas muscle. The Sphincter Vaginas arises from the body of the clitoris and the crus pubis; forms an expanse of an inch and a quarter around the anterior end of the vagina; 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 exist in the female, and have the same circumstances of origin and inser- tion, but are not so strong as in the male. Anterior to the corpus spongiosum on each side of the vagina, near its middle is frequently 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 laterally from its external orifice to the uterus; this membrane 300 OF THE TRUNK. being mucous will then be observed as continuous with the mucous membranes of the vulva and uterus. Near the vulva it is of a. vermilion tinge, but near the uterus it is grayish 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 re- mains consist in from two to six small tubercles, the Caruncula3 Myrtiformes. On its anterior or pubic wall the internal surface of the vagina is divided longitu- dinally by a ridge, commencing in a sort of tubercle, at the anterior orifice of the vagina just under the meatus urinarius; this ridge proceeds backwards, but becomes indistinct in approaching the uterus; from it on each side proceed transverse ridges or folds of the mucous membrane, which are particularly numerous and prominent before, but become indistinct and ir- regular near the uterus. The inferior side of the vagina has the same sort of arrangement as the supe- rior, only not so well marked. By cleaning the vagina and suspending it in water an abundance of mucous cryptas may be observed on its whole internal surface, which by an increased dis- charge produce leucorrhosa. FEMALE PELVIS. 301 The Uterus and its Appendages, the Fallopian Tubes and Ovaria. The LTterus is a compressed pyriform body with a cavity in its centre, placed between the bladder and rectum, has 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 pos- terior. 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 peritoneum, which are called ligaments. The peritoneum, after covering the uterus completely is reflected anteriorly upon the vagina, aud at each side of this reflection is a fugitive duplicature of the membrane denominated the Anterior Ligament, which goes 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 Ligament. The peri- toneum 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 302 OF THE TRUNK. Lateral or the Broad Ligaments. The peritoneum covers 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 Fal- lopian Tube, and on the posterior face of the septum, below the edge, and about an inch or a little more from the uterus, on each side, is an Ovarium. The peri- toneum adheres to the uterus by a cellular tissue, which is somewhat loose and can be easily dissected from it. Besides the ligaments mentioned, the uterus has two more, one on each side, called the Round Ligaments. They arise from the side of its body, between the du- plicatures of the broad ligaments, and pass under the peritoneum to the abdominal ring, through which they penetrate, and are lost upon the fat of the mons veneris and of the labia majora. They are of a fibrous struc- ture, 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 latter. In the centre of this projection is the Orifice of the Uterus, (Os Tineas,) which is not perfectly cylindrical 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 being FEMALE PELVIS. 303 higher up, it projects more into the vagina, and is easily distinguished by the finger. Behind the os tineas 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 extremity is 'somewhat larger. In the middle of this cavity, before and behind, longitudinally, is a line formed by an ele- vation of the lining membrane, and on each side of this line, transversely or obliquely, there are others presenting an arborescent arrangement. This is the Arbor Vitas. In the interstices of the transverse lines there are small mucous glands called Ovula Na- bothi, in consequence of this anatomists 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 sometimes divided into two sym- metrical halves by an elevated line on its anterior and posterior surface, running from above downwards. It is said, that in some cases, they have had a com- plete partition. The internal membrane of the uterus is a continua- 304 OF THE TRUNK. tion 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 villosities 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 men- struation. It abounds with mucous cryptas and ex- halent orifices. The texture of the uterus is essentially fibrous and of a white colour tinged with red, from having a great number of blood-vessels in its composition. The fibres have no determinate course, but are blended and inter- woven in every direction. Its muscularity is not ap- parent in the unimpregnated state. The Fallopian Tubes, (Tubas Uterinas,) 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 enlarge to end by an oblique trumpet shaped mouth, singularly fringed, called Morsus Diaboli, or Corpus Fimbriatum. This latter part of the tube is loose and pendulous, over- FEMALE PELVIS. 305 hanging the ovarium on the back part of the broad 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 lat- ter is principally concerned in forming its large extremity, and is rendered erectile in sexual excite- ment, probably by its great vascularity. The Ovaries, (Ovaria, Testes Muliebres,) are situated one on each side of the uterus, and on the posterior face of the broad ligament enclosed in a duplicature of it. They are compressed ovoids about half the size of the testicle, of a very light pink co- lour; are connected to the uterus by a small, vascular, arid fibrous chord, called Ligament of the Ovary, which is inserted into the uterus just below the fallo- pian tube. The external end of the ovary has one of the processes of the corpus fimbriatum or morsus diaboli adhering to it. The surface of the ovary is generally found some- what uneven, from a number of marks resembling cicatrices, ft has a complete peritoneal coat, and within this is another of a strong, compact, fibrous character, sending many processes internally, and which is 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 vesicles 39 306 OF THE TRUNK. 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 albu- minous light coloured fluid. The Bladder and Rectum, with unimportant excep- tions, 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 Fascias connecting the bladder to the sides of the pelvis, and the triangular ligament of the urethra also exist. SECTION II. Of the Female Mamma. The Mammas are two glandular bodies, situated over the thorax, upon the great pectoral muscles between the arm-pits and the sternum, and intended, in the female, for the secretion of milk. They are hemi- spherical, and vary 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 MAMMJE. 307 which creep beneath it. It is very extensible, but does not possess much power of contraction. Beneath the skin, between it and the surface of the gland, there is an abundance of cellular substance intermixed 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 pene- trated at different depths by this cellular and adipose matter, and its lobules are divided by irregular fossas 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 by the aid of a microscope, in a a gland filled with milk.* The roots of the excretory vessels, or the lactiferous ducts, arise from these grains; they are extremely fine, and unite, after a short course, to contiguous ones, by successive accumulations resembling the branches of a tree; large trunks are finally formed which terminate in still larger, placed in the centre of the gland near the * See Marjolin, vol. ii. p. 295. 308 OF THE TRUNK. base of the nipple. All the lactiferous ducts converge from the circumference of the gland to its centre; their course, however is very tortuous; their coats are thin, semitransparent, and very capable of extension and contraction. They are numerous, from two to four of them unite into a common trunk, called sinus, which is only a few lines long, and placed near the base of the nipple. These sinuses are about fifteen in number and are of different diameters, the largest about three lines wide, but others scarcely exceed the diameter of the lactiferous tubes. From the extremity of each sinus arises a small excretory duct, which conducts the milk to the summit of the nipple. This 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 these ducts, are united together by condonsed cellular membrane; they have no valves, neither have the lac- tiferous 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 cellular texture; this has been refuted by the researches of Cuboli. The excretory ducts of the different lobes are, for the most part, 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 milk duct of the nipple separately. FEMALE MAMMjE. 309 Some anatomists have thought that there is a direct communication between the roots of the lactiferous tubes, and the arteries, veins and lymphatics. Mas- cagni, after a very successful injection of the gland, in which he filled its vesicles with quicksilver, not meet- ing with such an occurrence, was induced to think that when such communication did happen it was by rupture. The Areola in virgins, is a rose coloured circle, 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 circumferenence, 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 secreted, according to some, an unctuous fluid for protecting the surface of the areola, while others consider it only as lactescent. The areola consists of a spongy tissue, beneath which there is no fat; it is susceptible of distention during lactation, or from sexual excitement. The Papilla or Nipple is the truncated cone in the 310 OF THE TRUNK. centre of the mamma, of the same colour with the areola, and surrounded by it. The milk ducts all terminate on its upper end. It is collapsed and in a very pliable state for the most part, but when ex- cited it swells, becomes more prominent, and of a deeper colour. Its skin is rough, and provided with numerous and very small papillas. Its internal struc- ture consists merely of the milk ducts, united by con- densed cellular membrane. The mamma is supplied with blood from the exter- nal thoracic, intercostal, and internal mammary arte- ries. Its veins attend their respective arteries. The nerves come from the brachial plexus and the inter- costals. Its lymphatics run into the internal mam- mary 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, by not involving them with the viscera; because it is the easiest manner of studying them, and such as the stu- dent most frequently adopts when left to his own dis- cretion; 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 injec- tions; this 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, 312 OF THE TRUNK. between it and the pleura; it then continues on 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 in 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 termi- nating ramifications united with those of the phrenic. 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 cardiac plexus, it also contributes to the same when the recur- rent nerve is separating from it. From a little below this place, the par vagum sends off the x4interior Pulmo- nary Plexus, derived principally from two branches, a large and a small one, which subdivide and go in front of the trachea and of the root of the lungs. The ramifications of this plexus follow generally the bron- chia and blood-vessels, into the substance of the lungs, but some of them are turned into the cardiac plexus. * For a further account of this nerve see the Neck. NERVES. 313 The trunk of the par vagum proceeds then on the outside of the bronchia, 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 successively five or six branches of different magnitudes, which leave the main trunk almost at right angles, divide and subdivide, and following the bronchia, 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, attaches itself to the oesophagus, being split into three or four fasciculi which spread out and unite again. From the crossing of the bronchia to the joining with the oeso- phagus, 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 oesopha- gus, and their fibres are reassembled into more consi- derable trunks. The left par vagum is distributed along the lesser curvature of the stomach, between the cardia and the pylorus, to the anterior side of the stomach, to the lesser omentum, and some of its branches extend to the left hepatic and the solar plexus. 10 314 OF THE TRUNK* 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 gastric artery to unite with the hepatic and splenic plexuses, and one trunk to the solar plexus. The Sympathetic, or Intercostal Nerve, is princi- pally 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 innomi- nata to the aorta, the other joining a plexus just be- low 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 dis- tance, 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 unite into a smaller number to form a plexus, which NERVES. 315 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 flbrillse 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 be- hind it. The second cardiac nerve of the left side, is derived from the middle and lower cervical ganglions of the sympathetic. Several branches being despatch- ed by the two ganglions, they form a plexus which sur- rounds the subclavian at the origin of the inferior thyroid and transversalis colli arteries. From this plexus several chords proceed longitudinally 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 considerable number of nervous filaments, formed by the combina- tion 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 trachea and bronehias and is fixed in loose cellular and adipose membrane at its upper part. Below, its meshes are 316 OF THE TRUNK. 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 in- ternal lamina of the pericardium, and are seen to enter into their structure. The cardiac plexus, penetrating from the base of the heart to the root of the aorta, is diffused through the muscular structure of the former, its trunks following the courses of the coronary arteries. The Sympathetic Nerve, from the last cervical ganglion, proceeds over the head of the first rib, and descends 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 one or two branches. At the lower part of the thorax it penetrates 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 the side of the bodies of the lumbar vertebras, being near the vena cava on the right side and the aorta on the left. About the middle of the body of each lumbar vertebra, it forms a ganglion which joins by one or NERVES. 317 two nervous filaments with the corresponding lumbar nerve, which filaments pass between the bone and the psoas muscle. From the loins, the sympathetic de- scends into the pelvis on the inner side of the foramina of the sacrum; here also it forms a ganglion corres- ponding with each sacral nerve, and detaches a fila- ment 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 pos- terior pulmonary plexus, and also are distributed in the form of a plexus on the aorta. From the sixth, seventh, eighth, ninth, and tenth thoracic ganglions, branches are sent off, which, descending obliquely on the sides of the vertebras, unite successively 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, or by penetrating the crus. From the tenth, and eleventh dorsal ganglions, fila- ments are in like manner, successively sent off, which form one trunk that penetrates into the abdomen, through the crus of the diaphragm; this constitutes the Lesser Splanchnic Nerve, which, in part, unites to the great splanchnic nerve, and the remainder goes to the renal plexus. The Great Splanchnic Nerve, having entered the 318 OF THE TRUNK. abdomen terminates in the Semilunar Ganglion. This ganglion is situated on the crus of the diaphragm, and on the sides of the coeliac and superior mesenteric arteries. It is frequently formed rather by a conge- ries 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, above the pancreas, and surrounds with its branches, the coeliac, superior mesenteric, and renal arteries. It is formed from the semilunar ganglions of both sides, and to their ramifications are added some from the par vagum and phrenic nerves. That portion of the solar plexus on the coeliac artery, assumes the name of coeliac, and dis- misses ramifications in the course of the gastric, hepatic, 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. From the inferior part of this plexus, proceeds a de- tachment in front of the aorta, to the inferior mesente- ric artery which supplies the left side of the colon and the rectum. NERVES. 319 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 spermatic artery, and are therefore called the Spermatic Plexus. In the male they are distributed on the chord and testis, and in the female on the ovarium and fallopian tube. From the lower part of the renal and solar plexus there preceeds 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 sympa- thetic of the loins. It divides, and following the course of the hypogastric artery on each side, is distributed to the bladder, rectum, and vesiculas seminales 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 Dorsal, the Lumbar, and the Sacral. Each arises as a solitary trunk from its appropriate spinal ganglion, and very soon divides into anterior and posterior fasciculi. The posterior is distributed to the muscles of the back, but the anterior has a destination not so Uniform. The anterior branches of the dorsal nerves are all 220 OF THE TRUNK. 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 axillary plexus. The second sends a branch through the ex- ternal 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 in- teguments 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 sacral, form the sciatic plexus, which supplies the posterior parts of the lower extremity. The further consideration of the spinal nerves is re- ferred to the Anatomy of the Limbs. 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- NERVES. 321 tioned, (see Thorax;) as well as that a line to subtend the base of its curvature, must be drawn from the sternal extremity of the third rib on the right, to the dorsal 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 advance of the others, and divides after an inch or an inch and a half of length, into right carotid and right subcla- vian. 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: of which the Inferior Thyroid, the Vertebral, and the Transverse Artery of the neck are mentioned in the article Neck. The remaining two, to wit, the Internal Mammary and the Superior Intercostal belong to the trunk. The Internal Mammary Artery, after its origin, descends 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 rectus muscle, anastomosing in it with the epigas- tric artery. It sends a branch which attends the phrenic nerve on the side of the pericardium; it sup- plies the intercostal muscles, anastomoses with the in- tercostal arteries and sends some branches to the mamma. 41 322 OF THE TRUNK. The Superior Intercostal Artery runs across the head of the first and second rib, and supplies the in- 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, the Posterior Me- diastinal and the Intercostal Arteries. The Bronchial Arteries are vessels intended for the nourishment of the lungs; the right comes from the . superior aortic 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 number, and are spent upon the oesophagus, as their name im- plies; the lowermost descends to the stomach. The Posterior Mediastinal, as their name indicates, supply the posterior mediastinum and its contents. The Aortic Intercostals supply, commonly, the ten inferior intercostal spaces. The upper ones have to 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. Ea^h one joins the rib near its tuber- cle, and keeps at its lower edge, between the internal and external intercostal muscles in the groove of the bone. The first branch is the dorsal, given off near NERVES 323 the spine; which passes to the muscles of the back, and despatches an arteriole through the intervertebral foramen to the medulla spinalis. When the intercostal arrives near the middle of the rib, it sends of a branch which passes near the upper edge of the lower rib. When it has got two-thirds of the length of the rib, it leaves the lower edge to be distributed to the inter- costal space and contiguous parts. The Abdominal Aorta passes almost in front of the vertebras, 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 vertebras of the loins it divides into the two Primitive Iliacs. The Phrenic Arteries come from the aorta imme- diately on the latter emerging between the crura of the diaphragm. They are two in number, and named from their situations, Right and Left; they ramify on the concave surface of the diaphragm. Their origin is subject to variations. The Coeliac Artery, (Arteria Coeliaca) is immediately below the phrenic; it is a large vessel about half an inch long, standing from the aorta at right angles, and divides into the Hepatic, Gastric or Coronary, and Splenic Arteries. The Hepatic Artery goes to the liver through the 324 OF THE TRUNK. capsule of Glisson, and is distributed through this viscus. Near the liver it sends off the Right Gastro Epiploic, which is distributed to the great curvature of the stomach and the contiguous parts. The Gastric Artery is between the other two; it joins the stomach near the cardia, and proceeds along the lessure curvature to the pylorus, supplying con- tiguous parts of the stomach. The Splenic Artery is the largest of the three. It goes tortuously along the upper edge of the pancreas to the spleen; in its course it sends to the stomach the Left Gastro Epiploic, which is spent on its greater ex- tremity and the left side of the greater curvature. From this vessel also are derived the Vasa Brevia of the stomach, and the Arteries of the Pancreas. The Superior Mesenteric, (Arteria Mesenterica Su- perior) 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 size as they approach the intes- tine. That branch 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. NERVES. 325 The Emulgent Arteries, (Arterias Emulgentes) 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 mesenteric. The right is the longest, and passes behind the ascending vena cava. They go to the kidneys and to the capsulas renales. The arterial distribution from the aorta here is subject to variations, the arteries of the capsulas renales coming sometimes from the aorta, and on other occasions from the emul- gents. There are also several arteries going to the adipose matter in which the kidneys are placed, equally unsettled in their origin. The Spermatic Arteries, (Arterias Spermaticse) arise immediately below the emulgents, one on each side; they are about the size of a crow-quill, and are re- markable for their length. They pass downwards to the testicles, behind the peritoneum, and before the psoas muscles, not far from the ureters, spermatic plexus of nerves, and spermatic veins. At the internal ab- dominal ring the spermatic artery meets with the vas deferens, and constituting a part of the spermatic chord is distributed on the testicle in the manner de- scribed in the account of that organ. In the female, these arteries go to the ovaria, fallopian tubes, and uterus. The Inferior Mesenteric, (Arteria Mesenterica In- ferior) arises below the spermatics; it is much smaller than the superior. Three branches proceed from it, 326 OF THE TRUNK. 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 Infe- rior. The superior anastomoses with the colica media, forming with it the great Mesocolic Arch. The others supply the sigmoid flexure of the colon, and the part just above it. A branch is continued from the inferior mesenteric to the rectum, constituting the superior Hemorrhoidal 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 Middle Sacral from its running down to the os ^occygis, just over the middle line of the sacrum. It sends branches on either side towards the foramjna in the sacrum. The Lumbar Arteries, (Arterias Lumbares) are from three to five in number on either side; they pass off at right angles from the aorta over the sides of the lumbar vertebras, some of their branches penetrate the intervertebral foramina to get to the medulla spinalis, others pass to the muscles of the back. Be- sides which, the lower parts of the parietes of the abdomen are supplied by them. They inosculate with the circumflexa ilii, with the epigastric and with the gluteal arteries. NERVES. 327 The Primitive Iliacs, (Art. Iliacas Communes) one on each side, are formed by the termination of the ab- dominal aorta; they extend from the fourth lumbar vertebra 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, (Arteria Iliaca Interna, or Ramus Hypogastrics,) gives off several branches, the origins of which differ considerably. The main trunk itself is of various lengths, and is distributed to the viscera of the pelvis and to the muscles on its external surface. Sometimes it is previously divided into two principal trunks, an anterior and a posterior. From it the following branches proceed. 1. The Ilio-Lumbar Artery, (Arteria Ilio Lumbalis,) is commonly the first branch of the hypogastric or of its posterior trunk. Arising from its posterior exter- nal part, it passes outwardly between the psoas magnus 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 Lateral Sacral Arteries, (Arterias Sacras Laterales,) come next, arising 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 328 OF THE TRUNK. inferior part of the cauda equina; they also anasto- mose with the middle sacral artery. 3. The Obturator Artery, (Arteria Obturatoria,) comes from the hypogastric, or one of its trunks, and passes along parallel with the brim of the pelvis; going through the obturator foramen it is distributed to the hip joint, and to the muscles on the upper internal part of the thigh. Its origin is occasionally from the epi- gastric. 4. The Middle Hemorrhoidal Artery, (Arteria Hemorrhoidea Media,) comes sometimes from the gluteal. 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 vesiculas seminales of the male, and the vagina and bladder in females. 5. The Uterine Artery, (Arteria Uterina,) is pecu- liar to females, and gets to the uterus between the laminas of the broad ligaments. 6. The Vesical Arteries, (Arterias Vesicales,) are derived from what was the umbilical artery of the foetus, and are distributed to the bladder. What remains of the hypogastric consists in two large branches, the Gluteal and the Ischiatic. 7. The Gluteal Artery, (Arteria Glutasa,) passes out of the pelvis at the upper part of the ischiatic foramen 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. Hav- ARTERIES. 329 ing got to its outside, the trunk of the gluteal divides immediately into branches which are distributed upon the gluteal muscles. 8. The Ischiatic Artery, (Arteria Ischiadica,) com- ing 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. It is distributed to the inferior edge of the gluteus maximus, and to the muscular structure near the sacrum and coccyx; also to the muscles, on the back and upper parts of the thigh. The Internal Pudic Artery, (Arteria Pudica Interna,) arises from the Ischiatic within the pelvis, emerges from the pelvis with the ischiatic, and then returns be- tween the two sacro-sciatic ligaments to the inner side of the tuberosity of the ischium, and continues on the inner side of the ramus of the ischium and of the pubes towards the symphysis. In this course it gives off several branches in the following order. A small branch to lower edge of pyriformis muscle. The Lower Hemorrhoidal Artery to the lower part of the rectum, and to the sphincter ani muscle. To the back part of the scrotum the perineal muscles and the skin it gives 42 330 OF THE TRUNK. the Perineal Artery, originating near transversus peri- nei muscle and passing in its direction. Upon the ar- rival of the internal pubic near the penis, it detaches to this body a branch which penetrates and ramifies minutely through the structure of the corpus spongi- osum urethrae. At the symphysis of the pubes it sends off a branch which gets to the dorsum of the penis, and extends longitudinally as far as the glans, being distributed 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 on the septum, and is distributed to the cells, by very minute branches, some of which go to the other side. The External Iliac Artery, (Arteria 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 about half-way between the symphysis of the pubes and the anterior superior spinous process of ihe ilium, having the anterior crural nerve on its outside and the external iliac vein on its inside. It gives off no branches till it reaches Poupart's ligament, when the Epigastric arises from it. The Epigastric Artery, (Arteria Epigastrica,) at first passes inwards; it then rises upwards obliquely till it reaches the exterior edge of the rectus muscle. Con- NERVES. 331 tinuing afterwards to ascend, it is spent upon the ante- rior parietes of the abdomen by many branches, some of which inosculate with the internal mammary. The Circumflex Artery, (Arteria Circumflexa Ilii,) arises from the external iliac near the epigastric. It runs along the posterior edge of Poupart's ligament to the spinous process of the ilium, thence it conti- nues its course near the internal margin of the crista, being distributed to the iliacus internus muscle. A branch of it, near the spinous process, rises upwards and is spent upon the abdominal muscles. It anasto- moses with the arteria ilio lumbalis. Veins of the Trunk. The Superior Cava, (Cava Descendens,) is sufficiently alluded to in the description of the thorax, to render a further notice of it here unnecessary. It receives the blood from the left arm and side of the head, by a trunk (the vena innominata formed by the union of the left subclavian and internal jugular vein) which crosses the sternum obliquely a little below its supe- rior edge. This venous trunk, and the correspond- ing one belonging to the right arm and the right side of the head which descends vertically, constitute in fact by uniting the Descending Cava. On a horizontal line with the upper edge of the root of the right lung is the point where the descending cava 332 OF THE TRUNK. 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 inferior intercostal veins of the left side. The trunk of the vena azygos, as stated, is on the right side of the posterior medi- astinum, and forms a regular and beautiful arch over the root of the right lung. The six superior Intercostal Veins of the left, dis- charge into the left 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 abdomen, by the union of the external and internal iliac veins into the common iliacs, and the subsequent junction of the latter at the fourth lumbar vertebra. This vein ascends on the right of the aorta, receives the Lumbar—the Spermatic—the Emulgent—the Cap- sular—the Hepatic and the Phrenic Veins and in its course penetrates the right opening of the diaphragm and terminates in the right auricle. Each artery of the pelvis has its corresponding vein; it is therefore unnecessary to describe the latter, ex- VEINS. 333 cept in regard to peculiarities. About the neck of the bladder, vesiculas seminales, and the base of the pros- tate there is a considerable accumulation of veins forming a very vascular plexus; 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, the Internal Iliac, 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 emulgent of that side. The emulgent and capsular veins corres- pond 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 that large trunk the vena portarum, the history of which is given in the account of the Liver. 334 OF THE TRUNK. SECTION III. The Thoracic Duct, {Vas Chyliferus.) The common trunk of the absorbent system com- mences most commonly at the second or third lumbar 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 formation, is sometimes subjected to a dilatation of various shapes and lengths, called the Receptaculum Chyli; after which it proceeds regularly upwards in front of the vertebra, 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 oeso- phagus. At the fourth dorsal vertebra it begins to in- cline 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 subclavian artery, between the in- ternal jugular vein and the scalenus anticus muscle; and then terminates by an orifice protected by two valves, in the fork formed by the junction of the left internal jugular and subclavian veins. Several interesting varieties occur in the vas chy- VEINS. 335 liferus; sometimes two trunks are formed originally on the lumbar vertebras, which run parallel with each other, and then unite at the lower dorsal vertebra. The thoracic portion of the duct varies in size and continuity, being divided once or oftener into two trunks, which unite again, and being also contracted at particular 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 occasional termi- nations of the lymphatic trunks in the region of the neck; in this plate the thoracic duct empties after a considerable dilatation, into the internal 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 lympha- tics 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 towards the junction of the right subclavian and internal jugular by four trunks, and then unite into one, which discharges itself at the posterior face of this junction. The venous orifice of this Trunk, like that of the Thoracic Duct, is secured from a regurgitation of blood by one or more valves. PART II. 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, directly over the spinous processes of the vertebras. Make a second incision from the upper end of the first, to the lobe of the ear. Make a third cut through the integuments from the acromion process to the poste- rior fold of the arm-pit. Lastly, make a cut hori- zontally 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 most superficial mus- cles of the back, the Trapezius and the Latissimus Dorsi. The Trapezius is a beautiful broad muscle, imme- diately under the skin, covering the back parts of the neck and thorax, and extending from the bottom of the latter to the top of the former. Its anterior edge MUSCLES OF THE BACK. 337 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 semicircular ridge of the occiput, by a tendinous membrane. It arises also from the five superior spinous processes of the neck, through the interven- tion of the Ligamentum Nuchas, and 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 cer- vical portion of these muscles, formed by the origins of both muscles united, is an elliptical expanse of ten- don lying over the ligamentum nuchas, and extended on each side. The ligamentum nuchas itself, is a ver- tical septum of ligamentous matter, extending from the central line of the occipital bone, to the spinous pro- cesses of all the vertebras of the neck. At its upper part, where the spinous processes of the neck are 43 338 OF THE TRUNK. short, this membrane is very broad, and divides com- pletely 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 expanse, from the seven inferior spinous processes of the back, and by a thick tendinous membrane from all those 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 three or four fleshy heads from the sides of the three or four inferior false ribs, which are interlocked with the inferior heads of the obliquus externus abdominis. From this extended origin the fibres converge, so as to form the posterior fold of the axilla, and to ter- minate in a flat, thick tendon, of two inches in breadth, which is inserted into the posterior ridge of the groove of the os humeri. The upper part of this muscle passes over the inferior angle of the scapula, and derives a fasciculus of fibres from it. * This origin frequently is tendinous at the back part of the ilium, and fleshy in front. MUSCLES OF THE BACK. 339 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 lum- borum. We shall then see that the serratus arises by a tendinous membrane from the two inferior 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 narrow muscle which arises by a thin tendon from the three inferior spines of the neck, and passing obliquely 340 OF THE TRUNK. downwards, is inserted into the base of the scapula op- posite the origin of its spine. The Rhomboideus Major arises also by a thin ten- don 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 obtained 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 Scapulae is placed between the poste- rior edge of the sterno-cleido-mastoideus and the ante- MUSCLES OF THE BACK. 341 rior of the trapezius; its lower end is just above the Rhomboideus Minor. It arises by rounded tendons from the three, four or five superior transverse process- es of the neck, between the scaleni muscles 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 ex- presses, it draws the scapula upwards. A good view of this muscle may be obtained in the front dissection 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 the five inferior cervical and of the four superior dorsal vertebras. 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 two superior cervical vertebras. It is customary to consider the part which goes to the head as Splenius Capitis, and the part below as Splenius Colli; the latter, in that case, is said to arise from the third and fourth dorsal vertebras. It draws the head and neck backwards. Between the spinous processes of the vertebras and the angles of the ribs, on either "side, there is a deep fossa filled up by muscles, some of them large and 342 OF THE TRUNK. 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 of the lumbar vertebras, and extend to the top of the thorax. They arise, tendinous externally, and fleshy internally, from the posterior surface of the sacrum by its exter- nal margin and spinous processes; they arise also, ten- dinous 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, in- deed, 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 in- serted, by small double tendons proceeding from its in- ternal surface, into the ends of the transverse pro- cesses of all the vertebras of the back, except the first. It also, from its outer edge, sends long slender tendons by which it is inserted into the under edges of all the ribs near their angles, except the two inferior. The Sacro Lumbalis is inserted from its outer edge into all the ribs at their angles, by long and thin ten- MUSCLES OF THE BACK. 343 dons, which are longer, the higher they are in- serted. By turning over this muscle from the other, towards the ribs, one may see coming from the eight lower ribs, as many slips, 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 connexion 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 pro- cesses, 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 vertebras, and is inserted tendinous into the spinous processes of the nine superior dorsal vertebras, except the first. It tends to keep the spine erect. Turn now the splenius from its insertions, which exhibits several muscles under it. 344 OF THE TRUNK. The Cervicalis Descendens is a small muscle placed at the upper portion of the thorax, between the inser- tions of the sacro lumbalis, and of the longissimus dorsi into the upper ribs; it looks, at first, very much like a continuation or appendix of the first, running to the cervical vertebras. 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 vertebras of the neck, between the levator scapulas 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 five middle cervical vertebrae. It draws the head back- wards. The Trachelo Mastoideus is at the inner side of the last muscle, in contact with it. It arises, by distinct tendinous heads, from the MUSCLES OF THE BACK. 345 transverse processes of the three superior vertebras 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 recognised 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 semicircular 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 situated between the complexus and the multifidus spinas; the course of its fibres renders it difficult to be distinguished from the latter. 44 346 OF THE TRUNK. It arises from the transverse processes of the six upper vertebras of the back, by tendons which are in- volved with those of the adjacent muscles, and passes up 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 multifidus. Like the other, it passes from transverse to spinous pro- cesses, and 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 processes of the seventh, eighth, ninth, and tenth dorsal vertebrae, and passes upwards obliquely, to be inserted, tendi- nous, into the sides of the spinous processes of the two lower cervical, and five upper dorsal vertebras. It draws the spine obliquely backwards. The Multifidus Spin^e lies under the muscles as yet mentioned, close to the bones of the spine; in order 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 spinous processes and posterior surface, also to the back part of the spine of the ilium. It there forms a belly of suffi- cient magnitude to fill up much of the cavity between the spines of the sacrum and the posterior part of the MUSCLES OF THE BACK. 347 ilium. It arises also from the roots of the oblique and transverse processes of all the vertebras 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 vertebras of the loins, of the back, and of the five infe- rior of the neck. This muscle consists of a great number of small bellies, which are parallel to each other, each arising from a semicircular 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 vertebras, 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 inferior semicircular ridge of the os occipitis, and part of the surface below it. 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 in- ternal edge of the first. It arises tendinous from the 348 OF THE TRUNK. tubercle on the back part of the first vertebra, and is inserted into the internal end of the inferior semicircular 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 semicircular ridjre 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 inserted 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 vertebras. In the neck they are double, in consequence of its spi- nous processes being bifurcated; in the back 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. MUSCLES OF THE BACK. 349 The Intertransversarii are also short muscles placed in a similar manner, between the transverse processes of the vertebras. In the neck they are double, in the back they are small, tendinous, and not well marked, and in the loins they are single and readily seen. 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, and pass from the transverse processes of the last cervical and the eleven superior dorsal vertebras, to the upper edges of all the ribs. They are twelve on either side of the spine, are tendinous in their origins, and inser- tions, with intermediate muscular bellies. The upper ones are small and thin, and they increase in magnitude as they descend. From the inferior edge of nearly all these muscles a fleshy slip is detached, which passes over the rib next below its origin, to the second rib below, and occasionally to the third. These slips are called Levatores Costarum Longiores. The others which descend from the 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 service, that of elevating the ribs. PART III. OF THE EXTREMITIES. CHAPTER I. OF THE UPPER EXTREMITIES. SECTION I. Of the Fascia. 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. On the shoulder, excepting its back part, and on the arm, this envelope has but few ligamentous fibres in it, and is principally condensed cellular membrane, but in the fore-arm its character is better developed, and is there decidedly 352 OF THE UPPER EXTREMITIES. aponeurotic. The aponeurosis of the fore-arm forms a complete sheath for its muscles. It is connected with the bony prominences at the elbow joint, more particularly the external and internal condyle and the ridges leading to them by processes called intermus- cular partitions or septa; with the ulnar side of the tendon of the biceps muscle, and the olecranon process of the ulna; it then passes down to the carpus, where it terminates both anteriorly and posteriorly in the an- nular ligament of the wrist. It is attached to the ulna along its internal margin, from the elbow joint to the wrist and several muscles arise from its interior sur- face. It is unnecessary to undertake, from the first, a regular dissection of this fascia, inasmuch as it will be gradually exposed in proceeding with the muscles. The upper extremity is most conveniently studied by detaching it from the trunk, taking care to leave the clavicle with the former. SECTION II. Of the Muscles of the Upper Extremities. The Muscles situated on the shoulder are six in number; they extend, for the most part, from the sca- pula to the head and neck ,of the os humeri. • MUSCLES. 353 1. The Deltoides arises from the inferior edge of the whole spine of the scapula, from the outer margin of the acromion process, and from the exterior third of the clavicle. Its origin, for the most part, is tendi- nous and fleshy, mixed; but at its posterior part, it is entirely tendinous. It is inserted by a tendinous point, into the triangu- lar rough surface, on the outer side of the os humeri, 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 tri- angular, and, when spread out, its upper margin being opposed to the insertion of the trapezius, is much more extensive than one would suppose. Its fibres do not converge regularly to its insertion like the radii of a circle; but the whole muscle is divided into several parts; between which, the interposition of intermuscu- lar tendons affects the course of the fibres, makes seve- ral 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 conceals the origin of the biceps flexor cubiti and of the coraco- brachialis. Its insertion is between the triceps exten- sor and the biceps flexor, and above the origin of the brachialis internus. 45 354 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 mar- gins. Forwards it terminates in a thick robust tendon closely connected with the capsular ligament of the joint, and which passes under the jugum formed by the articulation of the acromion with the clavicle. [t is inserted tendinous into the inner face of the great tuberosity of the os humeri and will assist in raising it. 3. The Infra Spinatus arises fleshy from all that portion of the dorsum scapulas 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 the acromion. This tendon is inserted into the middle face of the greater tuberosity of the os humeri. The infraspinatus rolls the os humeri outwards and backwards. 4 The Teres Minor is situated at the inferior margin of the infraspinatus, in the fossa of the infe- rior costa scapulas, and looks very much like a part of MUSCLES. 355 the infraspinatus, to which it occasionally adheres so closely, as to be separated with difficulty. It arises fleshy from the whole of the fossa, from the margins of the inferior costa, and from the cervix of the bone, to within an inch or so of its* inferior angle. It is inserted, tendinous and fleshy, into the outer face of the great tuberosity of the os humeri, just be- low the infraspinatus. It draws the os humeri 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 inferior angle of the scapula, and from a small part of its inferior costa; the interstice between it and the teres minor is considerable. It is inserted, by a broad tendon, into the posterior 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 interme- diate 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 that of the other. It rolls the os humeri inwards, and draws it down- wards and backwards. 6. The Subscapulars occupies all the thoracic sur- face of the scapula, being between it and the serratus 356 OF THE UPPER EXTREMITIES. 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 some- what like distinct muscles, but which all terminate, in a thick robust tendon, that adheres to the inferior sur- face of the capsular ligament. This tendon is inserted into the lesser tuberosity of the os humeri.. The subscapularis rolls the bone in- wards and draws it downwards. The Muscles of the arm are five in number, three anterior, and two posterior. 1. The Biceps Flexor Cubiti is situated immediately beneath the integuments, and forms the swell so ob- vious in the middle front part of most arms. It arises by two heads; the first called the long, is a round ten- don, 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 con- nected by loose cellular substance, but about half-way down the arm they are inseparably united. The biceps terminates below in a flattened oval ten- MUSCLES. 357 don, and passes in front of the elbow joint to be insert- ed 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 liga- ment, and then between the tendons of the latissimus dorsi and pectoralis major, where it is bound down by strong ligamentous fibres. The tendon below is super- ficial, 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 upper internal side of the arm, at the inner edge of the short head of the biceps muscle, with which it is connected for three or four inches. It arises tendinous and fleshy, from the middle face of the point of the coracoid pro- cess of the scapula, in common with the short head of the biceps muscle. It is inserted, tendinous and fleshy, into the internal 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 externus. From the lower end of this muscle there proceeds to the inter- 358 OF THE UPPER EXTREMITIES. nal condyle of the os humeri an intermuscular ligament, which separates the brachialis internus from the third head of the triceps. This muscle draws the arm upwards and forwards. 3. The Brachialis Internus is situated immediately beneath the biceps, and is concealed by it, except- ing the outer edge. It has a bifurcated fleshy origin from the middle front face 6f 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 dis- tance 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 supina- tor 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 scapulas. The second, called the Brevis, arises, by a sharp, tendinous MUSCLES. 359 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 Externus, 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 sepa- rated from the muscles in front of the arm by the liga- mentous septum, which arises near the middle of the os humeri, and runs to its condyles. 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 muscular fibres run in various di- rections 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 radial 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; it is the 5. Anconeus. This is a small triangular jnuscle 360 OF THE UPPER EXTREMITIES. 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 con- dyle 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 be impressed on the mind of the student, as it simplifies much the act of committing them to memory. The systematic treatises of anatomy describe the origin of each mus- cle 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 are con- nected to contiguous heads, by adhesion and by inter- MUSCLES. 361 muscular ligaments, and that there would be almost as much propriety in describing them 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 os humeri, and tendinous from the coronoid process of the ulna. It passes very obliquely across the fore-arm at the in- ternal 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 supi- nator radii brevis, occupying thereby about two inches of the middle of the bone. It rolls the hand inwards. 2. The Flexor Manus vel Carpi Radialis is placed at the ulnar side of the last muscle, and is also super- ficial. It arises, by a narrow tendon, from the lower front part of the internal condyle of the os humeri; fleshy from the intermuscular ligaments, fascia, and from the upper part of the ulna. It forms a thick, fleshy belly, terminating below in a tendon, which 46 362 OF THE UPPER EXTREMITIES. 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 radialis, and is superficial. Sometimes it does not exist. It is a small short muscle terminat- ing in a long slender tendon, and arises by a small ten- don from the internal condyle, and fleshy from the intermuscular ligament 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 Manus vel Carpi Ulnaris occupies, among the superficial muscles, the ulnar side of the fore-arm. It arises, tendinous from the internal con- dyle of the os humeri, fleshy, from the upper internal side of the olecranon; and, by a tendinous expansion much connected 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 upper side of the os pisi- MUSCLES. 363 forme by a round tendon, which begins high up at the radial margin of the muscle, and into which the mus- cular fibres run. Sometimes the tendon is continued over the os pisiforme, so as to be likewise inserted into the base of the metacarpal bone of the little finger. It bends the hand. 5. The Flexor Digitorum Sublimis Perforatus is concealed very much by the muscles just enumerated in consequence 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 interna] 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 is extended tendinous obliquely, for three or four inches along that line of the radius which is at the upper margin of the pronator teres. With these origins the muscle spreads over the front of the fore-arm at its upper part, from the radial to the ulnar margin. From the lower end of the muscle, four distinct ten- dons pass which commence much above the wrist, go beneath its anterior ligament, and, having got to the palm of the hand, diverge to the several fingers. To each finger, a tendon, is appropriated which passes in front of the metacarpal bone to the phalanges; and after having split into two, is inserted into the angle formed by the junction of the cylindrical and flat sur- faces of the second phalanx, near the middle. 364 OF THE UPPER EXTREMITIES. It bends the second phalanges on the first; its action may also be continued so as to clench the hand and to bend it on the arm. 6. The Flexor Digitorum 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 the olecranon processes; fleshy from the carpal margin of the base of the coro- noid 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 in front of it, like a ten- dinous membrane, which is gradually divided into sev- eral fasciculi, adhering to each other by cellular mem- brane. The fasciculated character of the tendons is still preserved when they go under the anterior 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 base of the third phalanx of the finger. It bends the last joint of the fingers, and by increased action, may flex the hand like the preceding muscle. 7. The Flexor Longus Pollicis lies in front of the radius, but beneath the flexor sublimis. It arises, by ♦ MUSCLES. 365 an acute fleshy beginning, from the radius just below 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, of a tendinous origin from the internal condyle of the os humeri. On the ulnar margin of this muscle a tendon is formed early, 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 minutias 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 and to the cuneiform and pisiform bones. Between 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, forming a bursa, which has the power of keeping them lubricated by a synovial secretion. 366 OF THE UPPER EXTREMITIES. The Vaginal Ligaments of the fingers extend from the roots of the fingers to the bases of the third pha- langes. They are of a ligamento-cartilaginous struc- ture, are attached on either side to the anterior edge of the phalanges, and are much thinner as they pass over the fronts of the finger joints than elsewhere. They are inelastic, their internal surface is extremely smooth, and kept continually lubricated by synovial fluid. Within the vaginal ligaments small tendinous frasna covered by a reflection of the synovial membrane are found to arise from the first and second phalanges, they run obliquely forwards, and terminate in the tendons of the two flexor muscles. We may also observe that in front of each joint, independently of the swelling of the articular extremities of the bones, the capsular lig- ament is thickened by an addition of cartilaginous 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 ten- dons 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 ridge at the inner surface of the ulna near its lower extremity, and from the front of the bone. MUSCLES. 367 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 hand. 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 con- dyle, 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 terminates near the middle of the radius in a flat tendon. It is inserted, by the latter, into a small rough ridge on the outer side of the radius, just above its styloid process. It rolls the radius outwards. 368 OF THE UPPER EXTREMITIES. 2. The Extensor Carpi Radialis Longior is situ- * ated beneath the former muscle. It arises, tendinous, and fleshy, from the space of the external ridge of the os humeri between the supinator longus and the ex- ternal 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 ex- ternal condyle, and from the external lateral ligament of the elbow joint. It forms a thick, fleshy belly, placed along the radius, and which terminates in a flat tendon about the middle olf 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 fascia. Cross- ing very obliquely the upper part of the radius and the MUSCLES. 369 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 superfi- cial, being placed between the extensor ulnaris and the extensor radialis brevior. It arises, tendinous, from the external condyle, and fleshy, from the intermuscular ligament of the contiguous muscles. As it approaches the wrist it sends off four tendons which pass to- gether through a common groove on the back of the radius. On the back of the hand these tendons di- verge, 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. 47 370 'OF THE UPPER EXTREMITIES. 6. The Supinator Radii Brevis can only be well seen by detaching the origins of the aforesaid muscles; 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 os humeri, 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 of the pronator teres. At the interstice be- tween 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 process 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 im- mediately below the anconeus, from the interosseous ligament, and from the back part of the radius just be- low 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 sty- loid side of the lower end 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. 371 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 second 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 interos- seous ligament; also from the back of the radius; it ter- minates near the wrist in a tendon, which passes through a groove on the back of the radius near the ulna. The belly of this muscle 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 other, and are spread in the form of a 372 OF THE UPPER EXTREMITIES. membrane on the back of the thumb, after the manner 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 ten- don of the common extensor belonging to the fore- finger. With the tendon of the extensor communis it is in- serted 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 strongly attached to the different ridges of the radius and ulna, and from its want of elasticity, perfectly adapted to prevent the tendons from springing out of their respec- tive grooves. It forms one jugum for the two first ex- tensors of the thumb, another for the radial extensors MUSCLES. 373 of the hand, a third for the tendon of the third exten- sor of the thumb, a fourth for the indicator and exten- sor 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 Aponeurosis Palmaris. This is a triangular tendinous membrane 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 bifurcates, to allow the flexor tendons to pass to the fingers, and is united to the contiguous sections by transverse bands or fraana. The muscles of the ball of the thumb and of the little finger are covered by a thin membrane extended from the lateral margins of this aponeurosis. The Palmaris Brevis is apt to be cut away uncon- sciously; it is just below the skin at the inner side of the hand. It consists of separate fasciculi unequally divided, and arises from the ligament of the wrist, and from the ulnar side of the palmar aponeurosis. It is inserted into the skin and fat at the inner mar- gin of the hand, and covers the muscles of the little finger. 374 OF THE UPPER EXTREMITIES. It contracts the skin of the hand. The Aponeurosis being removed, a good view is ob- tained 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 liga- mentum carpi annulare, and a little beyond its anterior 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, tendinous and fleshy, from the anterior surface of the ligamentum carpi annulare and from the projecting ends of the tra- pezium 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. This muscle is next to the skin. MUSCLES. 375 2. The Opponens Pollicis is beneath the abductor, 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 beneath the abductor pollicis and at the ulnar 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 trapezium, trapezoides, 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 phalanx of the thumb by tendon. The second or internal head arises, fleshy, from the magnum and unciforme, near their metacarpal surfaces, and from the base of the metacarpal bone of the middle finger. It is inserted into the inner sesamoid 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. 376 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 middle finger between its base and head. It is inserted, tendinous, into the inner part of the base of the first phalanx of the thumb near the internal 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, and 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 fleshy part of the ulnar side of the hand, or the ball of the little finger. 1. The Abductor Minimi Digiti Manus is the most superficial. It arises, fleshy from the protuberance on the internal side of the os pisiforme and from the con- tiguous parts of the annular ligament. MUSCLES. 377 It is inserted, tendinous, into the ulnar side of the 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 be- neath the abductor. It arises, fleshy, from the unci- form process of the os unciforme, and from the con- tiguous part of the annular ligament. It is inserted, tendinous, into the ulnar side of the base of the first phalanx of the little finger, being united with the tendon of the abductor, and with the tendinous membrane expanded over the back of the finger. It bends the little finger. The Adductor Metacarpi Minimi Digiti is placed beneath the Abductor and flexor, next to the metacar- pal 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 others, and thereby deepens the hollow of the hand. The Interosseous Muscles fill up the interstices of 48 378 OF THE UPPER EXTREMITIES. the metacarpal bones; they are seven in number, four on the palm, and three on the back of the hand. The latter ones arise by double heads from the contiguous sides of two metacarpal bones; the inner ones have each a single head only, which comes from the meta- carpal bone of the finger, which such interosseous muscle is intended to serve. As a general descrip- tion they all may be said to arise, fleshy and tendi- nous, from the base and sides of the metacarpal bones, and to be inserted tendinous, into the sides of the first phalanges, and into the tendinous mem- brane on the backs of the fingers, derived from the tendons of the extensor communis. The four first are very deeply seated, but the three others rather superficially. 1. The Prior Indicis is along the radial side of the first metacarpal bone, or that of the first finger and arisest 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. MUSCLES. 379 3. The Prior Annularis is at the radial side of the metacarpal bone of the third or ring finger, and 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 Interosseous Digiti Auricularis is at the radial side of the metacarpal bone of the little finger, and 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 communis from the back of the hand, we see the three posterior or double-headed interosseous muscles. 5. The Prior Medii is between the metacarpal bones of the fore and middle fingers, and 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 middle finger towards the thumb. 6. The Posterior Medii is between the metacarpal bones of the middle and ring fingers, and arises from the opposite sides and roots of these bones. It is inserted, tendinous, into the ulnar side of the first phalanx of the middle finger. 380 OF THE UPPER EXTREMITIES. It draws the middle finger towards the little. 7. The Posterior Annularis is between the meta- carpal bones of the ring and little finger, and 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. 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 scaleni muscles, is described in the account of the neck. The subclavian passes over the middle of the first rib be- tween the scalenus anticus and medius muscles, and afterwards goes between the first rib and the subclavius muscle to the arm-pit. Here it is called Axillary Ar- tery, {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 border- ing on, the internal edge of the coraco brachialis mus- BLOOD VESSELS. 381 cle. 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. Emerging from the axilla at this place, its name is changed into that of Brachial Artery, {Arteria Brachialis.) . The Arteria Brachialis descends the arm at the internal margin of the lower part of the coraco brachi- alis, and afterwards at the internal margin of the bi- ceps flexor cubiti. At the bend of the arm it is at the inner edge of the tendon of the biceps, and passes under its aponeurosis; and a little below the joint it splits into two branches of nearly equal magnitude, the Radial and the Ulnar Artery. The relative situation of this great artery with the nerves and veins of the part, should be closely observed; between the scaleni muscles, the majority of the nerves forming afterwards the axillary plexus, is above and somewhat posterior to the subclavian artery; 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, adi- pose and cellular membrane containing many lymphatic glands. 1. The Arteria Dorsalis Superior Scapula varies much in its origin; it comes sometimes from the sub- 382 OF THE UPPER EXTREMITIES. clavian, and on other occasions from the upper part of the axillary. Not unfrequently it is a branch of the in- ferior thyroid. In either the first or the last case, its course is very important to the surgeon, for it runs along the posterior margin of the clavicle towards its acromial extremity, and in an operation, by being opened, might be mistaken for the subclavian artery itself. When it comes from the axillary artery it is tor- tuous, and has to ascend to its destination, being com- pletely out of the way of an operation from above, upon the subclavian artery. Its 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-spinatus muscle and the shoulder-joint. 2. The Arterle Mammari^e Externa arise from the axillary just above the pectoralis minor. They consist in four principal branches, going uniformly to certain parts; but the origin of these branches varies, for some- times they are originally distinct trunks from the axil- lary artery, and on other occasions blended into one or more. 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. BLOOD VESSELS. 383 c. Thoracica Acromialis, making for the fissure be- tween the deltoid and great pectoral muscle, and dis- tributed to them along the margins of this fissure up- wards 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 about the anterior margin of the subscapularis 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 scapula a large trunk, the Dorsalis Inferior Scapulas, arises from the scapula- ris, and winds around the bone to be distributed to the infraspinatus and the contiguous muscles, an anasto- mosis being formed under the neck of acromion process, between the dorsalis 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, going 384 OF THE UPPER EXTREMITIES. between the bone and the coraco brachialis and biceps muscle, to be distributed to the articulation and to the contiguous muscles. 5. The Circumflexa Posterior is much larger, and arises from the axillary about the same place with the last, but commonly 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 shoulder joint and the contiguous muscles, espe- cially the deltoid. 6. The Profunda Humeri or Spiralis arises from the great artery of the upper extremity just below the ten- don 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 head of the triceps muscle. Et winds between this muscle and the bone very obliquely down- wards, and appears, at last, on the outer side of the arm, between the brachialis internus and the supinator longus; it reaches to the external condyle. In this course the profunda sends many branches to the triceps and to the contiguous muscles. Its origin is some- times from the scapular or from the posterior circum- flex artery. » BLOOD VESSELS. 385 7. The Profunda Minor is uncertain in its origin but comes commonly from the humeral two inches be- low the last; sometimes it is a branch of the last.' It is distributed on the internal surface of the triceps ex- tensor, 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. 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 internus muscle, and then over the ridge of the internal condyle to the groove between the condyle and the olecranon process, where it anastomoses with a recurrent branch of the ulnar artery. Several arterioles are also sent from the humeral or brachial artery to the biceps, brachialis, triceps, and coraco-brachialis, which are too irregular and too small to deserve description. The Humeral Artery it has been stated, is divided 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 in- 49 386 OF THE UPPER EXTREMITIES. sertion 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 Radial Artery (Arteria Radialis) in the early part of its course, is at the bottom of the fissure, be- tween the pronator teres and the supinator radii longus, afterwards it crosses the insertion of the former, runs parallel with, and in 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 be- tween the carpus and the extensors of the thumb, runs a little distance on the radial side of the back of the hand, and then penetrates to the palm between the base of the metacarpal bone of the thumb and of the fore-finger. It furnishes the following branches, col- lateral and terminating. 1. The Recurrens Radialis arises about the neck of the radius. It winds around the joint externally, be- tween the external condyle and the muscles coming from it, and anastomoses with the spiralis or profunda of the humeral artery; being distributed in many col- lateral branches, to the joint and contiguous muscles. 2. Several small and irregular muscular branches BLOOD VESSELS. 387 arise from the radial artery in its progress to the wrist; they have no appropriated names. 3. The Superficialis Vol^e 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 volas is the principal branch of the radial. 4. The Dorsalis Carpi arises from the radial at the carpus, runs transversely across the back of the latter and detaches the posterior interosseous arteries of the back of the hand. They anastomose with branches from the ulnar and interosseous arteries of the fore-arm. 5. The Magna Pollicis, a terminating 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 go along the sides of the thumb to its extremity, where they anastomose and terminate. 6. The Radialis Indicis, arising at the same place with the latter, runs along the metacarpal bone of the 388 OF THE UPPER EXTREMITIES. fore-finger, and along the radial side of the same finger to its extremity. 7. The Palmaris Profunda is the third terminating branch of the radial artery. It arises near the same place with the two last; crosses the hand between 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. 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. Being deeply seated, it goes, immediately after its origin, under several of the muscles of the internal condyle, and between the flexor sublimis and profundus; getting from beneath the flexor sublimis, it afterwards runs parallel with the ulna or nearly so, lying on the flexor profundus between the flexor ulnaris and the ulnar margin of the flexor sub- limis, 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 margin of the tendon of the flexor ulnaris. The ulnar artery, at the carpus, takes a very differ- BLOOD VESSELS. 389 ent course from the radial, for it passes over the ante- rior 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 palmaris 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 beyond the anterior margin of the annular ligament, and presenting its con- vexity forwards, terminates about the middle of the ball of the thumb at its inner margin. The branches sent from the ulnar artery are as follow: 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 r.amus- cules goes between the internal condyle and the olecra- non process, to anastomose with the arteria anasto- motica of the humeral. 2. The Interossea arises from the ulna just below 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 arteries. a. The Interossea Anterior is much the larger; it runs in contact with the interosseous ligament to the 390 OF THE UPPER EXTREMITIES. 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 interosseous ligament, and distributes to the back of the carpus and of the hand, branches, which anas- tomose with branches of the radial and posterior in- terosseal. b. The Interossea Posterior is sometimes a separate trunk, arising from the ulnar just above the former. In either case it soon perforates the interosseous liga- ment, to get to the back of the fore-arm. Here it sends backwards a Recurrent Branch to the back of the elbow, which anastomoses with the recurrens ulnaris 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, 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 ramuscles of the radial and interosseous, and conjointly they supply, with very small branches, BLOOD VESSELS. 391 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 bottom 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. 6. The Arcus Superficialis then sends a branch to the ulnar side of the little finder. Afterwards in sue- cession three digital branches are sent off, which, arriv- ing at the interstices between the heads of the meta- carpal 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 finger 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; and at the joints and extremities, anastomoses between the arteries of the two sides of the same finger occur. The Arcus Superficialis terminates on the radial side 392 OF THE UPPER EXTREMITIES. of the palm by a branch which joins the artery of the thumb coming from the radial. The most frequent distribution 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 collec- tion in the University, that this occurs oftener than any other single arrangement. The variety, in fact, is so great, that before a hand is opened it is not possible to know in what manner its arteries are distributed. Sometimes the radial artery furnishes one-half of the arcus sublimis, and the ulnar the other. On other occasions the interosseous artery, or the Superficialis Volas, is continued as a large trunk over the ligament of the wrist, and across the root of the thumb to join the arcus sublimis. Of the Veins of the Upper Extremities. These Veins are abundantly supplied with valves, and are superficial and deep-seated; the former lying beneath the skin have original names; the latter attend- ing the arteries on all occasions, are called after them. Anastomoses are numerous in both sets, but are parti- cularly so in the superficial, where plexuses are formed which surround the arm. Three principal superficial trunks are formed on the BLOOD VESSELS. 393 lower part of the fore-arm, one on its radial side, an- other on its ulnar, and the third between the two. 1. The Vena Cephalica first arises about the root of the thumb and fore-finger on the back of the hand; a distinct 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 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 Salvatella. 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 ana" pos- terior ulnar branches; it is then on the inner 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. 50 394 OF THE UPPER EXTREMITIES. This vein on the fore-arm frequently consists in two trunks, of which the posterior is the largest. 3. The Vena Mediana arises, by branches, from the wrist and from the palm of the hand; it forms a trunk on the front of the fore-arm, and which three or four inches below the bend of the arm, bifurcates. One branch, the Mediana Cephalica, joins the cephalic vein; the second, 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, one vein to each side of the artery. They anastomose frequently by branches which cross the arteries. 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 arm; on other occasions it joins it near or in the axilla, from which union results the axillary vein. NERVES. 395 The Vena Axillaris receives the veins correspond- ing with the circumflex, scapular, and thoracic arte- ries, in their proper .succession. It is fixed beneath the artery and very near it, in the same sheath of cel- lular substance. Under the clavicle it becomes Vena Subclavia; and as such it passes between the clavicle and the first rib at the inner side of the subclavian artery. It then leaves the artery to go in front of the scalenus anticus, whereas the artery goes between this muscle and the medius. After crossing the first rib it receives the superior dorsal vein of the scapula, the external jugular, and afterwards the internal jugular, besides several small veins from the skin and muscles of the neck. SECTION V. Of the Nerves of the Upper Extremities. The four inferior cervical and the first dorsal nerve, supply the upper extremity by an appropriation of nearly the whole of their anterior branches, which are of considerable magnitude, especially the three inter- mediate ones. They come out between the anterior and the middle scalenus muscle, being situated above and posterior to the subclavian artery, at various 396 OF THE UPPER EXTREMITIES. heights according to the origin of each nerve respec- tively. Almost immediately after disengaging them- selves 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 common trunk which splits into two; the seventh cervical and the first dorsal do the same; the sixth cervical also bi- furcates. It is under various combinations of these different primary divisions that the axillary plexus is formed, from which proceed the different nerves of the upper extremity. This plexus, from its close con- nexion with the great artery, must, of course, go be- tween the subclavius muscle and the first rib; and, in the upper part of the axilla, separate the axillary vein from the artery in some measure. The following branches are given off by the brachial plexus, besides the filaments from its roots to the sympathetic and phrenic in front, already mentioned in the account of the Neck. 1. The Nervus Scapularis is a small branch coming from the upper part of the plexus, commonly the fourth cervical nerve. It accompanies the arteria dorsalis scapulas superior to the notch 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 NERVES. 397 in number. They arise from the middle of the plexus and are divided into anterior and posterior branches, the former being distributed upon the pectoralis 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 between the teres minor and major in order to get to the internal surface of the deltoid muscle, where it terminates. In its passage it also furnishes branches to the sub- scapularis, the teres major and minor, the infraspinatus 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 ante- riorly to the integuments of the biceps, and posteriorly to those of the triceps. A little above the bend of the elbow, commonly where the median basilic joins 398 OF THE UPPER EXTREMITIES. the basilic vein, it divides into two terminating branches of nearly equal magnitude. The one next the inter- nal condyle lies in front of the basilic vein just at its junction with the median basilic, and continues 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 internal 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 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 obliquely 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 fila- ments to both of them. Its course being remarkably oblique under the biceps muscle, it makes its appear- ance superficially, only a little above the elbow joint near the external condyle. It then passes superficially between the skin and the supinator radii longus mus- cle, distributing filaments in its course, and near the lower part of the radius divides into two orders of NERVES. 399 fibres, one of which is distributed on the palmar side of the hand, and the other on the dorsal, but both go 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 tri- ceps. It appears on the outside of the os humeri be- tween the brachialis internus and the triceps muscle, running for some inches in contact with their intermus- cular ligament. While beneath the triceps it sends several branches to its heads. There are three prin- cipal trunks afterwards to this 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 exter- nal condyle. It continues superficial on the posterior external edge of the supinator radii longus muscle, 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 filaments pro- ceed to the contiguous heads of the muscles. 400 OF THE UPPER EXTREMITIES. b. The Ramus Profundus Dorsalis perforates the supinator brevis muscle, and gets 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 de- scending at the anterior margin of the supinator radii longus muscle, it joins with the radial artery and con- tinues in its company to a short distance below the middle of the radius. Here it crosses the bone ob- liquely beneath the tendon of the supinator longus, and then divides into a palmar and a dorsal ramuscle; the first being distributed to the muscles and integu- ments 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 arises from the brachial plexus, like the other nerves. It descends the arm at the inner edge of the biceps muscle along the ante- rior surface of the humeral artery, adhering firmly to it and to the deep-seated veins by cellular substance. As far as the elbow it sends off no branch of impor- tance. There, it lies at the side of the biceps tendon, crosses the lower part of the brachialis internus, and being beneath the aponeurosis of the biceps. It then perforates the pronator teres and gets between the NERVES. 401 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 apo- neurosis and the arcus sublimis. 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 de- scends with the interosseous artery in front of the in- terosseous ligament, and terminates in the pronator 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 extremities 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 liga- ment, 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 51 402 OF THE UPPER EXTREMITIES. • 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 internal margin of the ulna to the carpus, when it divides into ramuscles which supply the ulnar side of the integu- ments on the back of the hand, and the backs of the two last fingers. At the interval between the heads of the metacarpal bones of the middle and ring fingers, a considerable ramuscle joins one from the ramus su- perficialis anterior of the nervus radialis or musculo- spiralis. The Ulnar Nerve, having given off this dorsal branch, descends along the radial margin of the tendon of the flexor ulnaris and of the os pisiforme above the annular ligament, to the palm of the hand. Getting 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 digital branch of the median nerve. NERVES. 403 To conclude; the dissector should also attend to what are called the Intercosto-Humeral Nerves. They consist of a branch from the second, and another from the third thoracic, 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 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 supposed to be owing to the sympathy of these nerves with the cardiac. PART III. CHAPTER II. OF THE LOWER EXTREMITIES. SECTION I. Of the Fascia. The lower Extremity, from the pelvis to the foot, is enveloped by a strong Fascia or Tendinous Membrane lying between the skin and the muscles. This fascia consists, for the most part, of ligamentous fibres, pass- ing in the direction of the length of the limb, secured together by transverse filaments of the same matter, but by no means so abundant. Its structure under- goes some variations; its greater part is decidedly of the character just mentioned; but at the groin it is be- tween ligament and cellular membrane; the latter oc- casionally predominates so much, that the appearance FASCIA. 405 of the first is lost, particularly in in corpulent subjects. On the contrary, in the lean and such as have suffered from pressure and irritation of the part by hernial pro- trusion, the ligamentous structure is well developed. On the Gluteus Magnus also, this fascia exists as a condensed cellular membrane, sending in its processes between the faciculi of the muscle. The thickness of the Fascia Femoris is not uniform. On the outer side of the thigh, knee, and hip, it is very thick and strong; on the inner side it is thin, and com- pared with the other, weak. It is thick on the anterior part of the leg, and somewhat thinner on the pos- terior, but in neither is it so thick as at the outer part of the thigh. At the ankle it is connected with the bony prominences around it, and increasing in thick- ness 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 margin so as to keep itself tense. This membrane is very closely attached to the cel- lular membrane at every point of its external surface, and is kept tense all over by its bony connexions. Above, it arises, from the exterior margin of the pelvis, as constituted by the pubes, Poupart's ligament, the crista of the ilium, the side of the sacrum and the ischium. At the knee it is fastened to the condyles of the os femoris, and to the head of the tibia and fibula. On the posterior part of the thigh it sends in a long process, by which it adheres to the linea aspera- 406 OF THE LOWER EXTREMITIES. Its connexion with the knee and ankle, below, fixes it on the leg; besides which it adheres to the spine of the tibia. Its connexion 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 connexion 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. As an envelope to the muscles of the leg the fascia is highly useful in supporting and sustaining their action. The knowledge of its peculiar connexion at different parts of the lower extremity, is all important in the management of abscesses of that region. MUSCLES. 407 Though useful, it is not indispensable to make a complete investigation of the fascia at once, but the circumstances mentioned should be very carefully observed in extending downwards the muscular dis- section. SECTION II. Of the Muscles of the Lower Extremities. The Psoas Magnus, Psoas Parvus and Iliacus In- ternus are described at pages 255, 256. The Sartorius arises, by a short tendon, from the anterior superior spinous process of the ilium; a body 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 edge of the tendon is continued into the fascia of the leg, by which this muscle is pre- served in its spiral direction. The sartorius muscle is superficial, lying in its whole course immediately beneath the fascia femoris; it cross- 408 OF THE LOWER EXTREMITIES. es the rectus femoris, vastus internus, and triceps ad- ductor; 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 laminas of the fascia femoris. It is inserted, a little below the level of the tro- chanter major, into the inner face of the fascia femo- ris. 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, from the anterior inferior spinous process, by a round tendon, which is joined by another tendon coming from the superior margin of the acetabulum. It is inserted into the superior surface of the patella by a strong tendon, and intermediately by the ligamen- tum patellas into the tubercle of the tibia. It extends the leg. MUSCLES. 409 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 Inter- nus, and Crursus or Cruralis. Their heads are very distinguishable from each other; but below they are in- separably 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 below the trochanter major. Its origin commences in front, and passes obliquely around the bone to the linea aspera. It continues, afterwards, to arise the whole length of the linea aspera, and from the upper half of the line running from it to the external condyle. Its fibres pass inwards and downwards, and are inserted, 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 tendinous 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 origin, in front of the os femoris just on a level with 52 410 OF THE LOWER EXTREMITIES. 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. Its 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 Crurjeus 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 crurasus on the side of the vastus internus is not so distinct, as the fibres of the two muscles run to- gether; it is therefore necessary most frequently to cut through some of the fibres on the internal face of the os femoris on a level with the trochanter minor. The crurasus 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 unoccupied, for an inch, along the whole shaft of the bone, which is very readily seen by turning off the vastus internus. The Crurasus is inserted into the posterior face of the tendon of the rectus below, and into the upper sur- face of the patella. It also extends the leg. MUSCLES. 411 The Ligamentum Patellas is the common chord 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 infe- rior edge of the patella, and inserted into the tubercle of the tibia. Besides this, a fascia or tendinous ex- pansion, a continuation of the fascia of the thigh and called Involucrum, comes from the inferior ends of these muscles, and extends itself over the whole of the ante- rior and lateral parts of the knee joint, and is inserted 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 bo com- municated to the leg from the thigh.* 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 con- dyle 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 lateral and inferior part of its tubercle. * A case of this kind was lately in the Philadelphia Almshouse. 412 OF THE LOWER EXTREMITIES. 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 pubes between its crista 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 muscular mass consisting of three distinct portions, which are placed at the inner side of the thigh, and contribute much to fill up the vacuity between the thigh bones above. These portions are 1. The Adductor Longus which comes, by a round- ed short tendon, from the upper front part of the pubes near its symphysis; it forms a triangular 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 upper- most of the three; its origin is between that of the pectinalis and of the gracilis; its upper edge is in con- tact with the lower edge of the pectinalis. 2. The Adductor Brevis is the smallest of the three; MUSCLES. 413 it is situated beneath the adductor longus and pectinalis, and on the outside of the gracilis. It arises by a round- ed tendon from the middle front part of the pubes be- tween its symphysis and the foramen thyroideum, just below the origin of the first adductor. 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 pubes and from its de- scending ramus, also from the ascending ramus of the ischium as far as its tuberosity, occupying the 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 inserted 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 condyle. 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, 414 OF THE LOWER EXTREMITIES. 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-sci- atic ligament. The fibres of this muscle are collected into large fasciculi with deep interstices between them, and the lower edge of it is folded over the posterior sacro-sciatic ligament. 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 processes from the fascia femoris. It covers nearly all the other muscles on the back part of the pelvis, laps over its in- ferior margin laterally, and conceals the origins of the hamstring muscles. It draws the thigh backwards. MUSCLES. 415 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 crista and the semicircular ridge extending from the anterior superior spinous process to the sciatic notch; also from the lunated edge of the os ilium be- tween the anterior superior and anterior inferior spi- nous process, and from that part of the inner 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 major, and into the upper anterior part of the shaft of the bone just in front of the same 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 tendon, which is inserted into the anterior and superior part of the trochanter major, just within the anterior inser- tion of the gluteus medius. It abducts the thigh, and can also rotate the limb in- wards. There are several small muscles about the hip joint 416 OF THE LOWER EXTREMITIES. the most of which can be seen by the removal of the gluteus magnus. The Pyriformis arises, fleshy and tendinous, within 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 upper 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 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 connected 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 rough pit is. They also rotate the limb outwards. The Obturator Internus muscle is principally situ- ated within the cavity of the pelvis. It arises, fleshy, MUSCLES. 417 from all the pelvic margin of the foramen thyroideum except where the obturator vessels go out, and from the internal face of the ligamentous membrane stretched across it; also from the upper part of the plane of the ischium just below the linea innominata; 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 pit on the back of the os femoris at the root of the trochanter major. It rotates the limb outwards. The Quadratus Femoris is below the other muscles. 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 and 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 circumfe- rence of the foramen thyroideum, excepting the place 53 418 OF THE LOWER EXTREMITIES. 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 pos- terior surface of the os femoris, at the root of the trochanter major. The course of the tendon of this 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 tendon, 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 inser- tion 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 and is inserted into the upper part of the head of the fibula. This muscle flexes the leg on the thigh. MUSCLES. 419 The Semitendinosus is on the inside of the thigh, between the biceps and gracilis; it is superficial, being immediately under the fascia, and arises, in common with the biceps, from the back part of the tuberosity of the ischium; it also adheres, for three or four inches, to the inner edge of the tendon of this the long head of the biceps. About four inches above the knee it terminates in a long round 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 semitendinosus. 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 adductor magnus. It arises, by a thick round tendon, from the exterior upper part of the tuberosity of the ischium, which ten- don soon becomes flattened and sends off the muscular fibres obliquely from its exterior edge, to a corres- ponding tendon below. The latter passing behind the internal condyle and the head of the tibia, detaches a thin aponeurotic membrane under the inner head of the gastrocnemius, to cover the posterior part of the 420 OF THE LOWER EXTREMITIES. 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 compen- sated by the course of its fibres, which gives it great increase of strength. It flexes the leg on the thigh. Muscles of the Leg. These muscles are situated anteriorly, posteriorly, and externally. The Tibialis Anticus muscle is situated superficially 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, outer surface, and spine of the tibia, and from the interosseous ligament, to within three or four inches of the ankle. 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 malleolus internus, crosses the astragalus and os naviculare; and is inserted into the anterior part of the base of the cuneiforme internum, and into the adjacent part of the metatarsal bone of the great toe. MUSCLES. 421 It bends the foot, and presents the sole obliquely inwards. The Extensor Longus Digitorum Pedis, is also su- perficially 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 outer part of the head of the tibia, from the head of the fibula, and almost the whole length of its ante- rior angle; also from the upper part of the inter- osseous 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 ankle, and then diverging, are inserted re- spectively into the base of each toe, except the big, 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 a portion of the extensor longus; is found at its lower outer part, and cannot be naturally separated from it. [t arises from the anterior angle of the fibula, 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. 422 OF THE LOWER EXTREMITIES. The Extensor Proprius Pollicis Pedis is between the lower part of the tibialis anticus, and the ex- tensor longus. It arises from the fibula between its anterior and internal angles, by a tendinous and fleshy origin, which commences about four inches below the head of the fibula, and continues almost to its inferior extremity. A few fibres also come from the interos- seous ligament, and from the lower part of the tibia. The muscle being half penniform, the fibres run at its fore part obliquely to a tendon, which passes under the annular ligament, and over the astragalus sca- phoides and upper internal parts of the foot, to be inserted into the base of the first and second phalanx of the great toe. On the outside of the leg, between the fibula and fascia, are the two Peronei muscles. The Peroneus Longus seu Primus 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 ankle. 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 MUSCLES. 423 sulcus. It then runs through the groove of the os cu- boides, 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 meta- tarsal bone of the great toe. It extends the foot and inclines the sole obliquely outwards. The Peroneus Brevis seu Secundus is concealed in a great degree 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 ankle. 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 liga- mentous noose, and passing through the superficial fossa at the outer side of the os calcis, is inserted into the external part of the base of the metatarsal bone of the little toe. It extends the foot and presents the sole obliquely downwards. The Triceps Suras is placed on the back of the leg, and consists of Gastrocnemius and Soleus which in fact form but one muscle. 424 OF THE LOWER EXTREMITIES. The Gastrocnemius is the most superficial and con- ceals the other in consequence of its breadth. It arises from the condyles of the os femoris by two heads. One head arises, tendinous, from the upper back part of the internal condyle, and fleshy, from the ridge lead- ing to the linea aspera; the other head arises, by a broad tendon in the same way, from the external con- dyle and the ridge above it. A triangular vacancy is left between 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 surface 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 Gastro- cnemius 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 ob- lique 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 poste- rior tibial vessels. MUSCLES. 425 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 Achillis, which is inserted into the posterior inferior surface of the os calcis near its tuberosities. These two muscles extend the foot, and are all-im- portant in walking. The Plantaris is a singular little muscle concealed by the gastrocnemius, and has a short fleshy belly and a long tendon. It arises, fleshy, from the ridge of the os femoris just above the external condyle; passes across the capsular ligament of the joint, adhering to it in its course; the belly terminates somewhat below the head of the tibia in a long delicate tendon which descends between the inner head of the soleus and the gastrocnemius. At the place where these tendons unite, the tendon of the plantaris emerges from between them, and, run- ning at the inner edge of the tendo Achillis, is inserted into the inside of the os calcis just before the insertion ' of the tendo Achillis. It extends the foot. The Popliteus is a triangular muscle on the back of the knee joint. It arises from a deep depression on the 54 426 OF THE LOWER EXTREMITIES. exterior face of the external condyle, by a thick round tendon, which passes through the capsular ligament, being connected with the external semilunar cartilage,, and then forms a fleshy belly that passes obliquely in- wards and downwards. It is inserted, fleshy, into the oblique ridge on the back of the tibia just below its head, and into the triangular 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 Digitorum 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 Perforans 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 below the popliteus muscle, its origin being continued from the internal angle of the tibia almost to the ankle joint. It arises also, by tendinous and fleshy fibres, from the outer edge of the tibia, just above its connexion with the fibula at the ankle; and between this double order of fibres the tibialis posticus lies. The fibres pass obliquely into a tendon at the poste- rior edge of the muscle, which runs in the groove of MUSCLES 427 the internal malleolus, and is confined there by a strong ligamentous sheath. The tendon then gets to the sole of the foot along the sinuosity of the os calcis, and, being joined by a considerable tendon detached from the flexor longus pollicis, it divides into four branches which are appropriated to the four 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 mus- cle formed of oblique fibres, situated on the back part of the fibula, and at the outer side of the tibialis pos- ticus. It arises by an acute, tendinous, and fleshy be- ginning from the posterior flat surface of the fibula, commencing about three inches from its head, and con- tinuing almost to the ankle. 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 superfi- cial fossa of the tibia at the back of the ankle, 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 digitorum. 428 OF THE LOWER EXTREMITIES. giving oft' 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 toe, and from its connexion with the others will bend them also. The Tibialis Posticus is placed between, and con- cealed 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 continues its ori- gin from the whole of the interosseous ligament, and from the surfaces of the tibia and fibula, border- ing on the 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 malleo- lus internus, and is inserted into the upper internal part of the os naviculare. This tendon also divides in such 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. MUSCLES. 429 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, and arises, tendinous and fleshy, from the fore upper part of the greater apophysis of the os calcis, being connected with the origin of the annular ligament of the ankle. 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 inserted 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 increas- ed 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 membrane resembling ligament, that pass from the interior sur- 430 • OF THE LOWER EXTREMITIES. face of the skin to the aponeurosis plantaris. It fills up completely all the fissures in this aponeurosis, and adheres very closely to it, so that it requires much trouble to get out a fair dissection of the aponeurosis. The Aponeurosis, or Fascia Plantaris, is a liga- mentous membrane, extending from the tuberosities of 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 exter- nal portions are thin, and reticulated; they extend from the tuberosities 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 remark- ably strong 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 bifurcated, and dips down to be inserted on either side of the metatarsal bone near its head and into the bases of the first phalanges of the toes. Be- tween 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, separat- MUSCLES. 431 nig 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 Digi- torum Pedis, the outer is the Abductor Minimi Digiti, and the inner the Abductor Pollicis Pedis. The Flexor Brevis Digitorum Pedis arises, fleshy, from the large tuberosity of the os calcis by a narrow beginning, also from the interior surface of the aponeu- rosis and the tendinous septa between it and the con- tiguous 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 phalanges. The tendon for the little toe is often deficient. It bends the second joint of the toes. By detaching this muscle from its origin and turning it down, we bring into view the tendon of the Flexor Longus Digitorum Pedis, and its attachments be- hind, 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. 432 OF THE LOWER EXTREMITIES. 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 thin tendon, from the outside of the bone before its tuberosities. 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 flexing the toes. The Lumbricales Pedis are four small tapering mus- cles which arise from the tendon of the flexor longus just after its division, or while it is in the act of divid- ing. 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 back. 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 large 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 MUSCLES. 433 bone and into the base of the first phalanx of the great toe. It draws the great toe from the rest. The Flexor Brevis Pollicis Pedis is situated im- mediately at the exterior edge of the abductor pollicis. It consists of two bellies, parallel Avith each other, but separated by the tendon of the flexor longus pollicis; one is inseparably connected with the tendon of the abductor pollicis, and the other with the adductor pollicis. It arises, tendinous, in common with the calcaneo- cuboid ligament from the under part of the os calcis just behind its connexion with the os cuboides, and from the under part of the external cuneiform 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 out- side of the flexor brevis, and is extended obliquely-across the metatarsal bones. It arises, tendinous at the exter- nal part of the foot, from the calcaneo-cuboid ligament 55 434 OF THE LOWER EXTREMITIES. 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 phalanx of the great toe, and is closely united to the tendon of the external head of the flexor brevis pollicis. It draws the great toe towards the others. The Abductor Minimi Digiti Pedis forms the exter- nal margin of the sole of the foot, and is immediately beneath the aponeurosis plantaris. It arises, tendinous and fleshy, from the outer tuberosity of the os calcis, and also from the exterior part of the base of the meta- tarsal bone of the little toe. It is inserted, by a round tendon, into the exterior 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 with- in the tendon of the abductor minimi digiti. It arises from the ligament which is extended from the tube- rosity of the cuboid bone to the heads of the meta- tarsal bones; also from the root of the fifth metatarsal 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. MUSCLES. 435 The Transversalis Pedis is placed beneath the ten- dons of the flexor muscles. It is small, and lies across the anterior extremities of the metatarsal bones. 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 metatarsal bone3. 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. 436 OF THE LOWER EXTREMITIES. The Interosseus Secundus Primi Digiti, or the Ad- ductor Indicis Pedis, is also external or above. It is situated between the metatarsal bones of the first and second small toes, arises from the opposed surfaces 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 outwards. 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 of 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 metatarsal bones of the lesser toes, arising from the opposed 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 Interosseus Primus Digiti Tertii, or the Ab- ductor Tertii Digiti, is in the sole of the foot. It arises from the inside of the metatarsal bone of the third toe near its root, and is MUSCLES. 437 Inserted, tendinous, into the inside of the base of 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 metatarsal 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, or the Adductor, 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. SECTION III. Of the Blood Vessels of the Lower Extremities. The Femoral Artery, (Arteria Femoralis,) is a con- tinuation of the external iliac. It appears first on the 43S OF THE LOWER EXTREMITIES. thigh, half-way, or nearly so, between the symphysis pubis and the anterior superior spinous process of the ilium; emerging from beneath Poupart's ligament, it is there covered only 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 psoas magnus muscle, crosses the pectinalis, and the whole of the insertion of the adductor longus muscle. About one-third of the length of the thigh bone from below, it penetrates the insertion of the adductor magnus 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 little distance from it; it then inclines inwards and occupies the angle formed by the contact of the vastus internus, and the adductor longus. Above, the sartorius is at its outside; but as this mus- cle inclines very rapidly inwards, immediately after its origin, it in a little time begins to pass along the ex- ternal margin of the artery; and shortly afterwards covers the artery completely to the place where it penetrates the adductor. Where the artery lies in the angle formed by the adductor longus, and the vastus internus, it is covered by a strong interlacing of tendi- nous 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 BLOOD VESSELS. 439 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 (Arterias Pudendas Externas,) 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. 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, (Arteria Profunda Fe- moris,) is very happily called, by Professor Chaussier, Marjolin. 440 OF THE LOWER EXTREMITIES. La Grande Musculaire De La Cuisse, in consequence of its distribution. It is almost equal in size to the femoral itself, and arises from its posterior part on a level with the trochanter minor, but sometimes only five or six lines below Poupart's Ligament. It imme- diately begins to give off branches externally and in- ternally, but the main trunk of the artery continues for several inches in contact with the femoral artery or nearly so, and beneath it. It then terminates gradually by branches which penetrate to the back of the thigh. The profunda femoris is distributed as follows: a. The External Circumflex, (Arteria Circumflexa Externa,) 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- tella, and is about the size of a crow-quill. It first passes obliquely between the rectus and the crurasus, and then vertically under the anterior margin of the vastus externus, between it and the crurasus till it ter- minates about the knee, by anastomosing with the arti- cular arteries. It is principally distributed to the cruraeus and vastus externus. BLOOD VESSELS, 441 b. The Internal Circumflex, (Art. 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 under 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 mus- cles; they are irregular in number, size, and place of origin, and have no appropriate 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- chanter, and gets through the adductor magnus just below the quadratus femoris, to be 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, to be distributed about there and to the corresponding section of the long head of the biceps flexor cruris. 56 442 OF THE LOWER EXTREMITIES. The third penetrates the adductor magnus a little be- low the commencement of the origin of the short head of the biceps, and is distributed thereabout. The fourth penetrates the adductor magnus about an inch and a half above the hole for the femoral artery, and is distributed to the neighbouring part of the ad- ductor 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 knitting- needle, which are disposed of, upon the sartorius, ad- ductors, vastus internus, and integuments, but they are too irregular in number, origin, and course for syste- matic 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 magnus. This artery descends, in the course of the tendon of this adductor, to the knee, in front of the tendon, be- tween it and the vastus internus muscle. It is distri- buted to the parts lying along its course. The Popliteal Artery, (Arteria Poplitasa) is the continuation of the femoral after the latter has passed through the adductor tendon and got to the back of the lower extremity, 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 BLOOD VESSELS. 443 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 con- sequence of a thick envelope of fat, which fills up the hollow of the ham, and 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, (Articu- laris Superior Interna) sometimes exists as two trunks; it arises just above the internal condyle, perforates the adductor tendon, and, going horizontally, is spent on the inner side of the joint above. 2. The Superior External Articular Artery, (Articu- laris Superior Externa) arises just above the external condyle, passes horizontally between the femur and the biceps flexor, and is distributed to the upper 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 Inferior Internal Articular Artery, (Articularis Inferior Interna) arises on a level with the inferior part of the internal condyle. It descends obliquely, passes between the lateral ligament and the head of the tibia, and then mounts towards the patella, to be distributed in numerous branches. 5. The Inferior External Articular Artery, (Articu- laris Inferior Externa,) arises near the last, and some- times they are derived from a common trunk. It passes 444 OF THE LOWER EXTREMITIES. between the external lateral ligament and the head of the tibia, mounts afterwards towards 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 irregular branches to the other muscles, and sometimes the nu- tritious artery of the tibia. On a level with the aperture of the interosseous liga- ment, the popliteal artery may be considered as termi- nating by a division into two large branches, the An- terior Tibial, and the Posterior Tibial. The Anterior Tibial Artery, (Arteria Tibialis Anterior,) after getting through the interosseous fora- men, passes down the leg in front of the interosseous ligament and in contact with it; it passes also over the middle of the ankle joint to the dorsum of the foot, and is continued in a straight line to the interval between the metatarsal bone of the great toe, and of 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 ankle joint in front, and is continued in the course of a line drawn from this BLOOD VESSELS. 445 latter point to the junction of the two first meta- tarsal 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 the patella. 2. Several small arterial twigs are then sent to the muscles and periosteum on the fore part of the leg, but they have no name. 3. The Internal Malleolar, (Malleolaris Interna) arises from the anterior tibial near the joint, it passes under the tendon of the tibialis anticus, and is dis- tributed to the internal ankle, and the contiguous part of the foot. 4. The External Malleolar, (Malleolaris Externa) exists most commonly as two small branches, one arising on a level with the joint, and the other an inch or two above. They pass beneath the tendons of the 446 OF THE LOWER EXTREMITIES. extensor longus and the peroneus tertius, to the lower part of the fibula, and inosculate with the peroneal artery. 5. The Tarsal Artery, (Arteria Tarsea) arises from the anterior tibial just below the ankle joint; it runs outwardly under the tendons and the belly of the ex- tensor brevis, to be distributed to the upper outer part of the tarsus. 6. The Metatarsal Artery, (Arteria Metatarsea) arises just below the last, and is distributed by many branches on the upper part of the metatarsus. A suc- cessful injection demonstrates a branch of it in each of the three outer interosseous intervals of the metatar- sal bones above. 7. The Dorsal Artery of the Great Toe, (Dorsalis Hallucis) arises from the anterior tibial at the root of the first metatarsal bone, it runs in the superior part of the first metatarsal interval, and terminates 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, (Arteria Tibialis Postica) extends from the head of the tibia to the hollow of the os calcis; it is on the tibial side of the BLOOD VESSELS. 447 leg, and is placed between the soleus posteriorly, and the flexor 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 posterior tibial and is extended from the inferior edge of the popliteus muscle to the external ankle. 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 therefore deep and of dif- ficult access in the living body. After descending along two-thirds of the fibula, it divides into an anterior and posterior branch. The first traverses the inter- osseous 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 dis- tributed about the peroneo-tibial articulation and the adjacent parts. 2. Several small irregular muscular and cutaneous branches afterwards arise from the posterior tibial and at its upper part most commonly, the Arteria Nutritia Tibiae. At the ankle the posterior tibial is at the internal edge of the tendo Achillis, and still confined by the fascia of the part. It passes to the sole of the foot in 448 OF THE LOWER EXTREMITIES. the hollow of the os calcis, between the bone and the abductor muscle of the great toe. At the ankle it is on a line with the internal margin of the joint be- hind, and in contact with the posterior malleolus, between the tendon of the flexor longus pollicis, and that of the flexor longus digitorum. Having got to the sole of the foot it terminates by dividing into two branches, the Internal and External Plantar Arteries. The Internal Plantar, (Arteria Plantaris Interna,) is the smaller of the two; it is covered by the abductor pollicis, and passing between it and the internal inferior margin of the foot, it terminates at the anterior 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 remark- able is given off about the os scaphoides and cruizes along the internal margin of the abductor pollicis to its anterior end. Another makes its appearance superficially in the sole of the foot, in the fissure be- tween the abductor pollicis and the flexor brevis digi- torum, and goes as far forward as the other. The External Plantar, (Arteria Plantaris Externa,) inclines 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 BLOOD VESSELS. 449 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 external plantar is as follows: a. Half an inch from its origin it detaches backwards and outwards to the inferior and to the external parts of the heel a multifidous branch, which also sends an arteriole along the external edge of the abductor mi- nimi digiti. b. At the root of the fourth metatarsal bone a branch arises, called the External Digital Artery of the Little Toe, which goes first along the internal margin 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 suc- 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- 57 450 OF THE LOWER EXTREMITIES. nal plantar. At the head of the metatarsal bone it de- taches a branch which runs along the inner edsje of the great toe, and is united, by anastomoses, with the internal plantar artery. Of the Veins of the Lower Entremities. These veins are superficial and deep-seated. The more important of the first are the Saphena Magna and the Saphena Minor. 1. The Saphena Magna arises from the inside of the foot, about the great toe, and from its sole; it passes in front of the internal ankle, along the inside of the leg, over the internal condyle of the os femoris, 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 terior parts of 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 ankle and ascends on the outside of the leg to the ham, receiving contri- butions in its course; here it crosses the external head of the gastrocnemius muscle, and, dipping into the ham, empties into the popliteal vein. NERVES. 451 Frequent anastomoses occur between the saphena magna and minor. The origin and course of the deep veins of the lower extremity are so similar to the distribution and course of the arteries, that a description is needless. A venous tube always attends an arterial one, being in contact with it, enclosed in the same sheath, and call- ed by the same name. The smaller arterial branches in the leg and thigh have each two veins called Vena3 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. SECTION IV. Of the Nerves of the Lower Extremities. The Nerves of the Lower Extremity are derived from that part of the medulla spinalis which is situated in the lower dorsal and the upper lumbar vertebras. The 452 OF THE LOWER EXTREMITIES. lumbar nerves form a plexus behind the psoas magnus muscle, from which proceeds a cluster of nerves to supply the front part of the lower extremity, including both its skin and muscles. The sacral nerves form a plexus in the pelvis at the side of the rectum, from which proceeds the largest nerve in the body, the Sci- atic, appropriated to the supply of the skin and mus- cles 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, some- times 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 dor- sal. The anterior branches only of these 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, fibrillas pass out- NERVES. 453 wards and downwards over the quadratus muscle; some of their ramuscules are spent on the sides of the ab- dominal 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 up- per part of this plexus; it crosses the iliacus internus muscle, shaping its course towards the anterior supe- rior spinous process of the ilium. Here it involves it- self in the edge of the abdominal muscles, and, going on the posterior face of Poupart's ligament, at the in- ternal abdominal ring it joins the spermatic chord of the male, or the round ligament of the uterus of the fe- male. In the first case it is distributed to the sperma- tic chord and scrotum; in the second to the labium externum and mons veneris. The Cutaneus Externus arises from the lumbar plexus below the external spermatic. It passes across the iliacus internus towards the anterior superior spi- nous process about an inch below the spermaticus ex- ternus, and crosses the latter nerve just at that process. Emerging from the abdomen, by penetrating the com- mencement of Poupart's ligament, it is distributed, 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 patella. 454 OF THE LOWER EXTREMITIES. The Cutaneus Medius is given from the anterior crural, an inch or so above Poupart's ligament, coming 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 super- ficially 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 crural nerve; it is on the inner side of the cutaneus medius, emerges from the fascia of the thigh, and crosses the sartorius muscle two or three inches below the cuta- neus 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. The Cutaneus [nternus arises from the anterior crural nerve among the same cluster above Poupart's ligament. It divides into four or five branches of dif- ferent lengths, and is distributed to the integuments 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 magnus, and reaches as far down as the inner side of the knee. The Cruralis Anterior arises from the middle of NERVES. 455 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 ligament, about half an inch from the exterior margin of the femoral artery. Before it reaches Poupart's ligament it gives off a cluster of nerves, several of which go to the iliacus internus muscle, others form the superficial 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 gracilis. 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 adductor mag- nus, in a channel formed by this tendon and the origin of the vastus internus. The nerve alluded to is the Saphenus; it passes afterwards between the internal condyle of the os femoris and the sartorius muscle, attaches itself to the saphena vein, and is distributed to the integuments of the inner side of the leg and of the upper 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 from beneath the psoas magnus into the pelvis, near the sacro-iliac 456 OF THE LOWER EXTREMITIES. joint, 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 distributed to the heads of the adductor longus and brevis, and to the gracilis and integuments. The second terminates in the obturator externus, and the adductor 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 before the pyri- formis muscle. The sacral nerves amount to six in number, some- times only to five. They arise from the lower part of 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 anterior 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 increases till the fourth, but the fifth and the sixth are much* smaller, in fact only fibrillas. These posterior branches all communicate with each other, being dis- NERVES. 457 tributed to the head of the sacro-lumbalis and lon- gissimus dorsi, to the posterior edge of the glutasus magnus, to the integuments of the buttock, margin of the anus, and 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 hypo- gastric plexus. The fifth, and the sixth, when it exists, are distributed to the coccygeus, sphincter and leva- tor ani* The following small branches are sent from the Sciatic plexus:f a. Nervi Glutasi, one passing through the upper part of the sciatic notch along with the artery to the glutaeus medius and minimus, the other below the pyriformis muscle to the gluteus 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, * 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 the plexus, and the several branches proceeding from it, depart in a different manner. t They sometimes come from a common trunk called the small sciatic. 58 458 OF THE LOWER EXTREMITIES. 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 distributed to the integuments on the back of the leg. The Nervus Pudendalis Superior comes from the third and fourth sacral, occasionally receiving a con- tribution from the small sciatic when it exists. It goes in company with the internal pudic artery between the sacro-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 pubes with the trunk of the internal pudic artery, is distributed to the obturator internus, accelerator urinas, urethra, and afterwards getting be- tween the symphysis of the pubes and the penis, termi- nates 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 NERVES. 459 the pelvis between the pyriformis and the geminus su- perior. It crosses vertically behind the small rotator muscles of the thigh; being concealed by the inferior edge of the glutasus magnus; it is there about half-way between the tuberosity of the ischium and the trochan- ter major. Thence it descends on the back of the ad- ductor 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 di- vides into the Popliteal or Posterior Tibial, and Peroneal nerves. Occasionally this division 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 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 branch- es begin to diverge. The popliteal nerve continues straight downwards to the back and middle of the knee joint, and to the insterstice between the heads of the gastrocnemius muscle, whereas the fibular nerve goes along the inner posterior edge of the biceps flexor cruris, and passes between its tendinous insertion and the external head of the gastrocnemius muscle. In this course the following branches arc 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 460 OF THE LOWER EXTREMITIES. Internus Inferior, which arises just below the last, and descending upon the inner head of the gastrocnemius muscle 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 Adductor Magnus, Semimembranosus, Biceps and Semitendinosus. The Peroneal Nerve, (Nervus Peroneus) at the head of the fibula divides into two branches, the Pe- roneus Externus and the Tibialis Anterior; but before this division it sends a small branch to the external parts of the knee-joint, and two cutaneous branches called Peroneo-Cutaneus. The internal of the two latter descends behind the external head of the gastroc- nemius, and at the bottom of the leg is united to a division of the posterior tibial called the External Sa- phenus or Communicans Tibias. The external branch of the peroneo-cutaneous is distributed to the skin along the fibula. The External Peroneal Nerve, (Peroneus Externus) gets between the head of the peroneus longus and the fibula, then between the peroneus longus and the ex- tensor longus digitorum; it descends at the outer edge of the last muscle to the inferior third of the leg, giv- ing 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 Musculocu- taneous of the leg. NERVES. 461 The Anterior Tibial Nerve, (Tibialis Anterior) gets obliquely between the fibula, the peroneus longus, and the extensor longus digitorum to the front of the inter- osseous ligament, where it accompanies the anterior tibial artery. It passes with the artery under the an- nular ligament Of the ankle, 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 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 gastrocnemius muscle and perforates the origin of the soleus, going with the posterior tibial artery between this muscle and the flexor longus digitorum to the bot- tom of the leg. It gives off a. The External Saphenus, (Saphenus Externus or Communicans Tibias) which arises above the knee joint, and, descending between the skin and the gastrocne- mius, turns outwardly and anastomoses with the cuta- neous branch alluded to of the peroneal nerve. The common trunk passes behind the external ankle, along the external margin of the foot, and terminates on the two last toes, having given off a great number of cuta- neous branches. 462 OF THE LOWER EXTREMITIES. b. Branches to the heads of the gastrocnemius, soleus, 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 branches, divides in the hollow of the os calcis into Internal and External Plantar Nerves. The Internal Plantar, (Plantaris Internus) pro- ceeds along with 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) pro- ceeds with the artery of the same name to the outer edge of the foot between the flexor brevis digitorum 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 IV. LIGAMENTS. CHAPTER I. LIGAMENTS OF THE HEAD AND TRUNK. V 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 is inserted into the place where the condyle and neck of the lower jaw unite. There is also an accumulation of fibres internally and ex- ternally, which gives the joint the condition of lateral ligaments. 464 OF THE LIGAMENTS. 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 articular surfaces of these parts. There are also two distinct synovial membranes, one passing from the moveable 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 circumference 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 masseter and the internal pterygoid muscle. Also the small round liga- ment is seen, which goes from the styloid process to the appendix of the os hyoides. The Ligaments of the Spine. There is a capsular ligament with its synovial mem- brane, which surrounds on either side the superior ob- lique process of the first vertebra, and is inserted around the root of the corresponding condyle of the os occipitis. A circular ligament arises from the whole superior margin of the first vertebra, and is inserted into the margin of the great occipital foramen. HEAD AND SPINE. 165 The Occipito-Dentate Ligament passes from the point of the processus dentatus, and is inserted into the anterior part of the margin of the occipital foramen. The two Moderator or Oblique Ligaments, one on each side, arise from the lateral margin of the proces- sus dentatus; and are inserted into the inner margin of the foramen magnum. The Transverse Ligament subtends the cavity in the first vertebra for the reception of the processus den- tatus. The upper edge of this ligament is fixed by an appendix 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 contiguous oblique processes of the first and second vertebras. Between the bodies of all the vertebras except the first and second, a fibro-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 con- sistence. 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 59 466 OF THE LIGAMENTS. central pulpy part is confined by the other, and being also in a state of compression, it makes an articula- tion 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 in- tervertebral substance, and to the edges of the verte- bras. Where much motion is admitted, as in the neck and the loins, it is thinner than on the dorsal vertebras. 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 and os coccygis, on the posterior surface of the bodies of all the verte- bras, adhering to them and to the intervertebral sub- stance. It is narrower on the bodies of the vertebra: than on the intervertebral substance. The Yellow Ligaments; there are twenty-three pairs of them. They pass between the adjoining vertebras; one on each side, between the spinous and oblique pro- cess; and are best seen from the inside of the vertebral cavity. The first pair passes from the bony bridge of the second vertebra to that of the third, and so on suc- cessively to the sacrum. They are very elastic. HEAD AND SPINE. 467 Ligamentous fibres pass also between the spinous processes, and there are others between the transverse processes. The Ligamentum Nucha? is a tendinous septum be- ginning at the spinous process of the seventh cervical vertebra, and running up to the occiput, where it is fixed into its vertical ridge. It is connected interme- diately to the spinous processes of all the vertebras above the seventh, so that it forms a partition between the muscles of the two sides of the neck. All the Oblique Processes have their capsular and synovial membranes. SECTION 11. 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 vertebra), and admitting of motion. The Ligamenta Transversaria Interna arise from the inferior surface of each transverse process under its 46S OF THE LIGAMENTS. articular face for the tubercle of the rib, and are in- serted into the upper margin of the neck of the rib below; its fibres run obliquely inwards. The Liga- menta Transversaria Externa pass horizontally between the points of the transverse processes and the back of the ribs just beyond their tubercles, their fibres go outwards. The Ligamenta Cervicum Costarum are concealed by, and pass between the back of the neck of the rib, and the front of the corresponding transverse process. To be seen the rib must be sawed through in its length. At its anterior extremity there is a cavity in the rib into which the sternal cartilage fits and is there united. This junction is strengthened by short ligamentous 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 radiated liga- ments which lie in front of the joints. The Sternum is covered, both in front and behind, by a strong ligamentous expansion adhering very close- ly to it. From the second bone of the sternum and from the inferior margin of the seventh true rib, near it, a ligamentous fasciculus is sent to the cartilago en- siformis, and is called the Costo-xiphoid Ligament. PELVIS. 469 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 Uio Lumbar Ligament is stretched from the transverse and inferior oblique process of the last ver- tebra of the loins towards the posterior superior spi- nous process of the ilium and is inserted into the ad- joining part of the crista. It is much mixed with fat. Just below this is the Ligamentum Sacro-Spinosum, which is extended between the posterior superior spi- nous process and the third and fourth transverse pro- cesses of the sacrum. The Sacro Iliac Ligament is an assemblage of very short, strong, compact fibres, which surround this ar- ticulation. It is connected to the sacrum by its trans- verse processes and by the rough surface just on the iliac side of it, and to the ilium by the rough edge just behind its articular surface with the sacrum. In front the articulation is covered by short, strong fibres. The Os Coccygis is united to the sacrum by inter- vertebral substance and also by longitudinal ligaments on its front and back. The anterior ligament is not 470 OF THE LIGAMENTS. 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 ex- tremity. 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 from the side of the os coccygis. Its fibres converging 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 pubes by a con- tinued attachment along the inner margin of the ramus of the ischium. The Anterior Sacro Sciatic ligament has its origin somewhat confounded with that of the posterior. It arises from the side of the sacrum, below its junction with the ilium, and from the side of the os coccygis. Its course is more horizontal than that of the poste- rior, and it is inserted into the spinous process of the ischium. The articular surfaces of the sacrum and ilium are covered, each with its appropriate cartilage; that on PELVIS. 471 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 tena- cious substance. The Obturator Ligament closes the obturator fora- men, and arises from its margin; it is defective at the superior part where 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 lamellas 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 or Inter-pubic Ligament is a strong tendinous membrane of half an inch in breadth, occupy- ing the very top of the arch of the pubes, and passing from one bone to the other; it is spoken of in the ac- count of the fascias of the pelvis. In front of this joint there are several other fasciculi of fibres, which get collectively the name of the Ante- rior Pubic Ligament. CHAPTER II. SECTION I. Of the Ligaments of the Upper Extremities. The Clavicle and the Sternum are very firmly united by the breadth of their articulating surfaces, and by the thickness of their ligaments. The Radiated Ligament arises from the front of the internal end of the clavicle, and is inserted around the margin 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 sternum, 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 be- low with the sternum, above with the clavicle and 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. UPPER EXTREMITIES. 473 The Costo-Clavicular, or Rhomboid Ligament, arises from the cartilage of the first rib, and is inserted into the tubercle on the under surface of the clavicle, near the sternum. , The Scapuloclavicular Ligaments are two in num- ber. The first is a capsular ligament with its synovial membrane, which unites the acromial end of the clavi- cle to the acromion process. This ligament being 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 outer margin of the conoid, a ligamentous membrane, called the Trapezoid Ligament, is extended towards the acromial end of the clavicle. The conoidal and the trapezoid ligaments join each other behind at an angle which is near a right angle; they are both very strong and fibrous. In front of the subclavius muscle, arising from the root of the coracoid process and going to the clavicle, and anterior end of the first rib, is the Ligamentum Bicorne. The Triangular Ligament of the Scapula is extend- 60 474 OF THE LIGAMENTS. ed over the shoulder joint. Its basis arises from the whole outer margin of the coracoid process, and its apex is fixed to the inner margin of the acromion be- neath the cla^cle. It is thinner in the middle than at either edge. The Coracoid Ligament of the Scapula is stretched across its coracoid notch, and converts it into a fora- men for the vessels and nerves. Of the Shoulder Joint. The Scapulo-Humeral Articulation is formed by the 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 lat- ter. A fold or thickening of it, called the Accessory Ligament, passes from the coracoid process towards 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' bicipital groove of the os humeri, which is afterwards reflected 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 also with the fibrous ring called the Glenoid Ligament, which surrounds the glenoid cavity and by being attached to its edge deepens it. UPPER EXTREMITIES. 475 Of the Elbow Joint. The Elbow Joint has a capsular ligament arising from the upper margin of the articular surface of the os humeri including its sigmoid cavities, and inserted into the margin of the articular surface of the ulna, and into the cdronary ligament of the radius. This capsule has additional fibres internally, and externally, called Lateral Ligaments, or Brachio-Ulnar, and Brachio-Radial. The first arises from the internal condyle, and spreads in a radiated manner to be in- serted into the inner edge of the coronoid and ole- cranon process. The second arises from the external 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 process 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 capsular liga- ment and the lower is loosely attached to the root of the neck of the radius. On the anterior and posterior surfaces of the capsule of the elbow joint, there are small and irregular fibres termed accessary ligaments, but the capsule is particu- 476 OF THE LIGAMENTS. larly thin under them, in order to accommodate 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 ca- vity of the ulna, a small quantity of vascular adipose matter is found traversing the articular cartilage and interrupting it. 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 ob- lique fibres which pass from the radius to the ulna. In it are several perforations for blood-vessels, one par- ticularly large is just at the tubercle of the radius. There is a small ligamentous band called the round ligament, at the upper part of the opening for the vessels, and which goes from the base of the coronoid process to the radius,just below its tubercle. Of the Joints at the Wrist. The articulation of the radius with the ulna be- low is formed into a distinct joint, by the lateral pro- UPPER EXTREMITIES. 477 jection of the articular cartilage of the radius between the ulna and the cuneiform bone. The capsule which unites this joint is very loose and is the sacciform liga- ment. The upper Wrist Joint is formed between the lower end of the radius 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 con- tinued between the ulna and the cuneiform bone, and is inserted into the margin of the articular head form- ed by the scaphoid, lunar, and cuneiforhi bones. The External Lateral Ligament arises from the styloid process of the radius, and is inserted into the scaphoid bone, the trapezium, and anterior annular ligament. The Internal Lateral Ligament arises from the styloid process of the ulna, and is inserted into the inner side of the cuneiform bone and partly into the pisiform and the corresponding part of the anterior ligament, which confines the flexor tendons. By cutting open this articulation we see the synovial membrane of the part, and a fold of it called the Mucous Ligament, which passes from between the scaphoides and lunare, to the radius. We also see the cartilage of the radius projecting between the cuneiform bone v 478 OF THE LIGAMENTS. and the head of the ulna, and forming with the head of the ulna, a distinct joint, as stated. The Articulation between the first and the second row of carpal bones is formed by a capsular liga- ment, which goes from the first to the second row, being strengthened laterally by a multiplication of its fibres, constituting lateral ligaments internally and externally; the fibres of the capsular ligament and of the radio-carpal joint are continued into this. There are also several fasciculi of fibres which run in varied directions, some oblique and some transverse, fastening the two rows to- gether as well as the individual bones of the same row. When this joint is opened we find but one synovial mem- brane for the two rows of bones where they are in con- tact, 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 motion 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 al- most stationary. UPPER EXTREMITIES. 479 The Metacarpal Bones of the fingers are connected to each other at their bases by transverse ligamentous fasciculi; they are also connected at their heads in the same manner by the inferior palmar ligaments. 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 mem- brane. The capsule being thickened at its sides, thus forms lateral ligaments. In front it has a cartila- ginous thickening which forms a trochlea for the flexor tendon. Behind, it is imperfect, the principal strength being derived from the tendon of the extensor muscle. The Phalanges are articulated in the same way with each other, that they are articulated with the metacarpal bones. CHAPTER III. SECTION I. 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 en- closed 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 femoris. The capsular ligament varies in its thickness at differ- ent places; in front it is a fourth of an inch thick, inter- nally it is somewhat thinner, and posteriorly where it is covered by the quadratus muscle it is thinnest. From the anterior inferior spinous process, accessory fibres arise, which give to the capsule an increased thickness above. By cutting open the capsule, we see that its internal face, as well as the surfaces of the bones, are covered by a delicate synovial membrane which is thrown into longitudinal folds on the neck of the os femoris; and that a strong ligamentous chord passes from one side of the notch in the lower part of the acetabulum to the INFERIOR EXTREMITIES. 4sl other, leaving an opening below for the introduction of vessels 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 ex- tremities of the notch of the acetabulum by a bifur- cated termination, and into the inferior margin of the chord, subtending the notch, will be seen. The depth of the acetabulum is increased by the Cotyloid ligament, which surrounds its margin, 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 syno- vial 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. The fascia of the lower extremity in passing from the thigh to the leg covers this joint in front as far back as the lateral ligaments and takes the place of a regular capsular ligament. It is there called In- volucrum. 61 482 OF THE LIGAMENTS. The External Lateral Ligament arises from the tube- rosity of the external condyle, and is inserted into the head of the fibula. The Internal Lateral Ligament arises from the tuberosity of the internal condyle, and is inserted into the inner side of the head of the tibia being continued for some distance down the edge of the bone. The front of the joint is much strengthened by the tendon 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 col- lection 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 patella fall upon the tibia, a good view of its internal arrange- ment may be obtained. The synovial membrane will be seen arising from the cartilaginous margin of the head of the tibia, and around that of the patella; but it is reflected on the front and sides of the condyles of the os femoris half an inch or more above the margin of its cartilaginous surface. On both sides of the liga- ment 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 patella an oblong ridge covered by the synovial membrane. It is called, on the outside of the patella, the Ligamentum Alare Minus, INFERIOR EXTREMITIES. 483 and on its inside, the Ligamentum Alare Majus. These ligaments terminate each in a point below the patella where they are in contact with each other; and from this place a duplicature of synovial membrane, ending on the crucial ligaments, and on the os femoris between its condyles, is extended to the posterior part of the articulation and is called the Ligamentum Mucosum. 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' partially blended with those of the semilunar cartilages. The Posterior arises from the external face of the internal 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 carti- lage. These ligaments are exterior to the synovial membrane. The Semilunar Cartilages, two in number, are placed between the tibia and the os femoris; to see them well the last bone must be removed, leaving them on the tibia. They are thick at their exterior circumference and are brought to a thin edge internally; are fastened to the capsular and the lateral ligament by their outer margin, but the internal is loose; their upper and under 484 OF TIIELIGAMENTS. surfaces are covered by the synovial membrane. The internal is longer from before backwards than trans- versely and is semicircular; the external is almost cir- cular, in each of which cases they exactly conform to the corresponding articular surface of the tibia. The posterior end of both of these cartilages is fixed to the tibia between the spine on its top, and the posterior crucial ligament; their anterior ends are inserted into the tibia before the same spine. Occasionally a trans- verse ligamentous band is seen to unite their anterior extremities. The height to which the synovial membrane ascends above the patella, should be noticed by the student, as well as a large bursa just behind the tendon of the ex- tensor muscles, which most commonly communicates 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 cap- sular ligament is thickened in front and behind, which occasions the names of Anterior and Posterior Li 37 Internal Lateral Lig. of Wrist, 477 Internal Lateral Lig. of Knee, 482 Internal Malleolar artery, 445 Internal Mammary vein, 332 Internal Mammary artery, 321 Internal Plantar nerve, 462 Internal Plantar artery, 448 Internal Pudic artery, 329 Interossea Artery, 389 Inter Pubic Ligament, 471 Interosseous Ligament of arm, 476 Interosseous Ligament of Leg, 485 Interossea anterior artery, 389 Interossea posterior artery, 390 Interosseus Digiti Auricularis, 379 Interspinals muscles, 341 Intertransversarii muscles, Intestinal Canal, Involucrum, Iris, Isthmus of Fauces, Ischiatic artery, Joints at Wrist, Kidneys, Knee Joint, PAGE 349 227 481 119 147 329 476 245 481 Labia Externa, 393 Labia Interna, 295 Labyrinth, 133 Lachrymal Gland, 112 Lachrymal sac and ducts, 112 Lamina Spiralis, 135 Large Intestine, 230 Laryngeal Nerves, 46 Larynx, 152 Lateral Half arches of fauces, 146 Lateral Ligaments of uterus, 302 Lateral Nasal Nerve, 41 Lateral Sacral arteries, 327 Lateral Ventricles, 57 Latissimus Dorsi, 338 Laxator Tympani muscle, 132 Left Gastro Epiploic artery, 324 Left auricle, 172 Left Lumbar region, 186 Left Ventricle, 173 Left Lateral Ligament, 234 Lenticular Ganglion, 125 Left Hypochondriac region, 186 Left Iliac region, 11,187 Levator Ani muscle, 288 Levator anguli oris, 6 Levator Labii Inferioris, 8 Levator Labii Superioris alaeque Nasi, 5 Levator Palati, 148 Levator Scapulas muscle, 340 Levatores Costarum muscles, 340 Ligamentum Alare Majus, 483 Ligamentum Alare Minus, 482 Ligamentum Arcuatum, 254 Ligamentum Bicorne, 473 Ligamenta Cervicum Costarum, 468 Ligaments of Foot, 487 Ligaments of Head and Spine, 463 Ligaments of Head and Trunk, 463 Ligamentum Nuchas, 337,467 Ligaments of Inferior Extremities, 480 Ligamentum Patellae, 411 Ligaments of Pelvis, 469 Ligament of Poupart, 189,190 Ligamentum Pulmonis, 177 INDEX. 499 Ligaments of Spine, 464 Ligamentum Suspcnsorium Penis, 266 Ligamentum Teres, 481 Ligaments of Thorax, 467 Ligamenta Transversaria Inter, 467 Ligaments of Upper Extremities, 472 Ligament of Winslow, 482 Linea Alba, 190 Linea Semilunaris, 190 Lineas Transversas, 190 Lingualis, 20,143 Lingual Nerve, 42 Liquor Morgagni, 122 Liver, 233 Lobus, 127 Lobulus Anonymus. 235 Lobulus Caudatus, 235 Lobulus Spigelii, 235 Longissimus Dorsi muscle, 34 Longus Colli, 21 Lower Extremities, 404 Lower Hemorrhoidal artery, 329 Lumbar arteries, 326 Lumbricales muscles, 374 Lumbricales Pcdi^ muscles, 432 Lungs, 176 Lymphatic Glands of Neck, 28 Magna Pollicis artery, Malleus, Male Pelvis, Masseter, Meatus Auditorius Externus, 1 Medulla Oblongata, Mediastinum, Median Basilic vein, Median Cephalic vein, Membrane of Jacobs or Tunica Jacobi, Membrana Papillaris, Membranous Portion of Urethra, Membrana Tympani, Mesentery, Mesocolon, Metatarsal artery, Middle Hemorrhoidal, Middle Thyro-hyoid Ligament, Middle Sacral artery, Mitral Valve, Moderator Ligaments, Modiolus, Mons Veneris, Motores Externi, Motor Externus, Mouth, Mucous Ligament of Wrist, Muscles of Abdomen, Muscles of Back, 387 131 258 9 26,27 61 1G4 394 3:>4 121 120 270 121) 224 224 446 328 155 326 174 465 135 293 69 125 143 477 187 336 PAGE Muscles of Eye, 113 Muscles of Face, 2 Muscles of Foot, 429 Muscles on Back of Fore Arm, 367 Muscles in front of Fore Arm, 360 Muscles of Leg, 420 Muscles of Lower Extremities, 407 Muscles of the Neck, 11 Muscles of Thorax, 159 Muscles of Upper Extremities, 352 Musculi Accessorii, 343 Musculi Pectinati, 168 Multifidus Spinas muscle, 346 Mylo Hyoideus, 19 Nasal Nerve, 142 Nails, 493 Nervus Axillaris or Circumflexus, 397 Nerves of basis of Brain, 66 Nervus Cutaneus Internus, 397 Nerves, according to Gall, 101 Nervus Musculo Cutaneus, 398 Nerves of Head and Neck, 38 Nervus Ischiadicus, 458 Nerves of Lower Extremities, 451 Nervus Medianus, 400 Nervus Motor Oculi, 67 Nervus Obturatorius, 455 Nerve Olfactory, 66 Nerve Optic, 67 Nerves of Orbit, 124 Nervus Pudendalis Superior, 458 Nervus Radialis or Musculo Spiralis, 399 Nervus Scapularis, 396 Nervi Subscapulares, 397 Nervi Thoracici, 396 Nervus Trigeminus, 68 Nervus Trochlearis, 68 Nervus Ulnaris, 401 Nerves of Upper Extremities, 395 Nerves and Vessels of Trunk, 311 Nipple, 309 Nose, 139 Nutritia arteria, 385 Nymphas, 295 Obliquus Capitis Superior muscle, 348 Obliquus Capitis Inferior muscle, 348 Obliquus Externus muscle, Obliquus Internus muscle, Obturator artery, Obturator Externus muscle, Obturator Internus muscle, Obturator Ligament, Occipito Dentate Ligament, Occipito Frontalis, GSsophagus, 189 192 328 417 416 471 465 2 151 500 INDEX. PAGE PAGE Oesophageal arteries, 322 Phrenic Nerve, 48,311 Olfactory nerves, 141 Pia Mater, 54 Omenta, 221 Pigmentum Nigrum, 119 Omentum Colicum, 223 Pineal Gland, 60 Omentum majus, 221 Pinna, 127 Omentum minus, 221 Pituitary Gland, 66 Omentum Gastro Splenicum, 223 Plantaris muscle, 425 Omo Hyoideus, 17 Platysma Myodes, 12 Ophthalmic artery, 124 Pleura, 163 Opponeus Pollicis, 375 Pleura Costal is, 164 Optic nerve, 125 Pleura Pulmonalis, 164 Orbicularis Oris, 8 Plexus Choroides, 59 Orbicularis Palpebrarum, 4 Plexus Lumbalis, 452 Orifice of Parotid Gland, 146 Pncumogastric, 70 Os Hyoides, 152 Pomum Adami, 153 Os Orbiculare, 131 Pons Varolii, 64 Os Tineas, 302 Posterior Annularis, 380 Ostium Venosum, 169 Posterior Auris, 32 Ovaries, 305 Posterior Carpal Ligament, 372 Ovula Nabothi, 303 Posterior Chamber of Eye, 123 Portio Dura, 39 Palatine Nerve, 44 Posterior Indicis, 378 Palmaris Brevis muscle, 373 Posterior Ligaments of Uterus, 301 Palmaris Longus, 362 Posterior Mediastinum, 164 Palmaris Profunda artery, 368 Posterior Medii, 379 Palalo Pharyngeus muscle, 147 Posterior Tibial artery, 446 Palpebral Ligaments, 110 Posterior Sacro Sciatic Ligament, 470 Pancreas, 243 Posterior Vertebral Ligament, 466 Pancreatic arteries, 324 Popliteal artery, 442 Papillae, 144 Popliteus muscle, 425 " Capitatae or Maximas, 144 Popliteal nerve, 461 " Mediae, 144 Portio Dura, 69,138 " Villosas, 144 Portio Mollis, 69,137 " Filiformes, 144 Preputium, 266 Papillae of Kidney, 247 Primitive Iliacs, 327 Par Vagum, 45,312 Prior Annularis, 379 Parotid Gland, 25 Prior Indicis, 378 Parts concerned in Femoral Prior Medii, 379 Hernia, 207 Processus Brevis of Incus, 131 Pectinalis muscle, 412 Processus Brevis of Malleus, 131 Pectineal Fascia, 209 Processus Gracilis of Malleus, 131 Pectoralis Major muscle, 159 Processus Longus of Incus, 131 Pectoralis Minor muscle, 160 Profound artery, 439 Penis, 266 Profunda Humeri artery, 384 Pericardium, 115 Profunda Minor artery, 385 Perforating arteries, 441 Promontory of Ear, * 130 Perineum, 278 Pronator Quadratus muscle, 3fi6 Perineal artery, 330 Pronator Radii Teres muscle, 361 Peritoneum, 219 Prostate Gland, 263 Peroneus Brevis, 423 Psoas Magnus muscle, 255 Peroneus Longus, 422 Psoas Parvus muscle, 255 Peroneus Tertius," 421 Pterygoideus Externus, 11 Peroneal artery, 447 Pterygoideus Internus, 11 Peroneal Nerve, 460 Pterygoid Nerve, 40 Peroneo Tibial Articulation, 484 Pulmonary Artery, 172 Pharyngeal Nerve, 46 Punctum Lachrymale, 111 Pharynx, 148 Pyloric Orifice of Stomach, 225 Phrenic arteries, 323 Pupil, 120 INDEX. 501 Pyramid, PAGE 130 Pyramidalis, 194 Pyriformis muscle, 416 Quadratus Femoris, 417 Quadratus Lumborum, 256 Radial artery, 386 Radialis Indicis artery, 387 Radiated Ligaments, 472 Receptaculum Chyli, 334 Rectum, 231,258 Recurrens Radialis artery, 386 Recurrent Tibial artery, 445 Rectus Abdominis muscle, 193 Rectus Capitis anticus major, 21 Rectus Capitis anticus minor, 21 Rectus Capitis Lateralis, 22 Rectus Capitis Posticus major muscle, 347 Rectus Capitis Posticus minor muscle, 347 Rectus Femoris muscle, 408 Recurrens Ulnaris artery, 389 Regio Pubis, 187 Renal Capsules, 249 Renal Plexus, 319 Rete Mucosum, 490 Retina, 121 Retrahens Auriculas muscle, 129 Rhomboid Ligament, 473 Rhomboideus major muscle, 340 Rhomboideus minor muscle, 339 Right Auricle, 168 Right Gastro Epiploic artery, 324 Right Hypochondriac region, 186 Right Iliac region, 187 Right Lateral, 234 Right Lumbar region, 186 Right Ventricle, 169 Rima Glottidis, 158 Root of Lung, 177 Round Ligaments of Bladder, 260 Round Ligaments of Liver, 234 Sacculus Sphericus, 136 Sacro Lumbalis muscle, 342 Sacro Iliac Ligament, 469 Saphena Magna, 450 Saphena Minor, 450 Saphena Vein, 209 Sartorial Fascia, 209 Sartorius muscle, 407 Scala Tympani, 135 Scala Vestibuli, 135 Scaleni muscles, 22 Scapha, 127 Seapularis, 383 Scapulo Clavicular Ligaments, 473 PAGE Schneiderian Membrane, 141 Sciatic Plexus, 456 Scrobiculus Cordis, 187 Scrotum, 272 Sebaceous Glands, 494 Sebaceous Organs, 494 Semicircular Canals, 133 Semilunar Valves, 171 Semilunar Cartilages, 483 Semimembranosus, 419 Semispinalis Dorsi muscle, 346 Semispinalis Colli muscle, 345 Semitendinosus muscle, 419 Septum Lucidum, 58 Septum Pectiniforme, 268 Serratus major anticus muscle, 161 Serratus Superior Posticus, 340 Serratus Inferior Posticus muscle, 339 Shoulder Joint, 474 Skin, 489 Sinuses of Dura Mater, 52 Sinus Pulmonalis, 172 Sinus of Ridley, 53 Sinus of Valsalva, 171 Sinus Venosus, 168 Small Muscles of. Hand, 373 Small Intestines, 228 Solar Plexus, 318 Soleus muscle, 424 Spermatic arteries, 325 Spermaticus externus nerve, 453 Spheno palatine ganglion, 40 Spheno Palatine nerve, 142 Sphincter Ani muscle, 281 Sphincter Vaginas muscle, 299 Spinal Accessory Nerve, 43,73 Spinal Marrow, 71 70 Spinalis Dorsi muscle, 343 Splanchnic nerves, 317 Spleen, 240 Splenic artery, 324 Splenius Capitis muscle, 341 Splenius Colli muscle, 341 Splenius muscle, 341 Spurzheirn, iqi Stapedius, 133 Stapes, 13 j Stomach, 225 Sterno-cleido mastoideus, 13 Sterno-hyoideus, 16 Sterno-thyroideus, 17 Stylo-Glossus muscle, 19,143 Stylo-hyoideus, 18 Stylo maxillary ligament, 16,464 Stylo-Pharyngeus, 19 Subclavius muscle, 161 Subclavian artery, 321 Submaxillary Gland, 26 502 INDEX. Sublingual Gland, PAGE 27,145 Thoracica Longa, PAGE 382 Subscapularis muscle, 355 Thoracica Superior, 382 Sub Pubic Ligament, 471 Thorax, 159 Sulcus Transversalis, 235 Thyreo-Arytenoideus, 157 Sulcus Umbilicalis, 235 Thyreo-Epiglottideus muscle, 158 Superficialis Dorsi Penis, 330 Thyreo-hyoideus, 17,156 Superficialis Volas artery, 387 Thyroid Cartilages, 153 Supra Spinatus muscle, 354 Thyroid Gland, 23 Superior Maxillary nerve, 40 Thyroidea Superior, 31 Superior Mediastinum, 164 Thyroidal Veins, 38 Superior Mesenteric artery, 324 Thymus Gland, 182 Superior Hemorrhoidal artery, 326 Tonsil Gland, 147 Superior Intercostal artery, 322 Transverse Ligament, 465 Superior Pubic Ligament, 197 Transversus Perinei muscle, 281 Supinator Radii Brevis, 370 Tricuspid Valve, 170 Supinator Radii Longus, 367 Trigeminus, 39 Sympathetic, 47,314 Trochlearis nerve, 125 Trunk, 159 Tarsal artery, 446 Tuberculum Loweri, 168 Tarsi Cartilages, 110 Tubercula Quadrigemina, 60 Temporalis, 10 Tubuli Seminiferi, 275 Tendo Achillis, 424 Tubuli Uriniferi, 247 Tensor Palati muscle, 147 Tunica Albuginea, 274 Tensor Tarsi, 114 Tunica Arachnoidea, 54 Tensor Tympani muscle, 133 Tunica Choroidea, 118,19 Tensor Vaginas Femofis, 408 Tunica Conjunctiva, 111 Tentorium, 51 Tunica Hyaloidea, 122 Testes, 272 Tunica Sclerotica, 117 Teres Major muscle, 355 Tunica Vaginalis communis, 200,274 Teres Minor muscle, 354 Tunica Vaginalis Testis, 274 Thigh, Artery of 437 Tympanum, 129 Tibialis Anticus, 420 Tibialis Posticus, 428 Ulnar Artery, 388 Tongue, 143 Umbilical region, 186 Torcular Hierophili, 53 Upper Extremities, 351 Trachea, 178 Urachus, 260 Trachelo Mastoideus muscle, 344 Ureters, 248 Tragicus muscle, 129 Uterine Arteries, 328 Tragus, 127 Uterus and Appendages, 301 Transversalis Abdominis, 193 Uvula, 140 Transversalis Cervicis muscle, 344 Transversus Auras muscle, 129 Vagina, 297 • Transversalis Linguas, 144 Vaginal Ligaments of fingers, 366 Transversalis Pedis muscle, 435 Valve of Brain, 61 Trapezoid Ligament, 473 Valve of Thebesius, 169 Trapezius muscle, 336 Valvulas Conniventes, 229 Triangular Ligament, 473 Vasa Brevia, 324 Triangular Ligament of Urethra, 282 Vasa Efferentia, 276 Triangularis Sterni muscle, 162 Vasa Vorticosa, 119 Triceps Abductor Femoris, 412 Vas Deferens, 276 Triceps Extensor Cubiti, 358 Vastus Externus muscle, 409 Triceps Suras, 423 Vastus Internus muscle, 409 Thalamus Nervi Optici, 57 Vena Cava Descendens, 331 Third pair or Motor Oculi, 125 Veins of Lower Extremities, 450 Third Ventricle, 60 Veins of Trunk, 331 Thoracic Duct, 184,334 Veins of Upper Extremities, 392 Thoracica Acromialis, 383 Vena Axillaris, 395 Thoracica Axillaris, 383 Vena Azygos, 184 INDEX. 503 Vena Basilica, 393 Vena Cava Ascendens, 332 Vena Cephalica, 393 Vena Galeni, 53 Vena Mediana, 396 Vena Portarum, 234 Venae Satellites or Comites, 396 Velum Pendulum Palati, 144 Ventricles and Convolutions, 98 Ventricle of Galen or Morgagni, 154 Verticales Linguas, 144 Vessels of Orbit, 124 Vesiculas Seminales, 264 Vesical arteries, 328 Vestibule, 134 Vestibulum, PAGE 296 Villi, 230 Viscera of Thorax, 162 Vitreous Humour, 122 Vulva, 293 Yellow Ligaments, 466 Zona Coriacea, 135 Zona Membranacea, 135 Zona Ossea, 135 Zona Vesicularis, 135 Zygomaticus major, 6 Zygomaticus minor, 6 •■A^-lii' #, •"%OTT.. 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AUNER'S CATALOGUE. Clarke on Climates. Churchill on Pregnancy. Carpenter's Materia Medica. Calhoun on Suspended Animation. Caldwell's Cullen, 2 vols. Carlisle on old Age. Cazenave on Diseases of the Skin. Castle's Manual of Surgery. Chapman on the Viscera. Cholera, Bell and Condie on. Cholera, Scoutetten on. Chisholm on Malignant Fever. Cheyne on Dropsy. Corvisart on the Heart. Coates's Popular Medicine, Collins's Midwifery. Condie on Children. Coxe's Medical Dictionary. Cook on Nervous Diseases. Colhoun's Prout on the Urinary Organs Comstock's Botany. Combe on Infancy. Combe on Insanity. Comstock's Mineralogy. Cooper (Sir A.) on Hernia. Cooper's Lectures on Surgery, by Tyrrell. Carmichael on Venereal. Curling on Tetanus. Curry on Cold Water. Cooper and Travers's Surgical Essays. Copeland on the Rectum. Clutterbuck on Bloodletting. Cooper on Dislocations. Conversations on Chemistry. Colles's Surgical Anatomy. Curling on the Testis by Goddard. Curry on Yellow Fever. Cutler on Bandages. Cheyne on Croup. Coxe on Insanity. Cook on White Mustard Seed. Cooper's Surgical Dictionary. Coster's Physiological Practice. Coxe's Refutation of Hervey's Claim. Clark on Consumption. Christison on Poisons. Christison on the Kidney. Chase on Hernia. Chittty's Medical Jurisprudence. Churchill's Midwifery. Churchill on Females. Carpenter's Physiology. Civial on Stone. Chase's Medical Student's Guide. Dunglison's Practice of Medicine, 2 vols Druitt's Modern Surgery. Dunglison's Therapeutics and Materia Medica, 2 vols. Dick on Digestion. Darrach on the Groin. Davies' Pathology. Dupuytren's Surgery. Duparque on the Uterus. Dunglison's New Remedies. Dunglison's Medical Dictionary. Dunglison's Physiology, 2 vols. Dunglison on Hygiene. Dunglison's Medical Student. , Deslandes on Onanism. Daniel on Fever. Dewees's System of Midwifery. Dewees on Treatment of Children. Dewees on Diseases of Females. Dewees's Essays.' Dewees's Practice. Desault's Surgery, 2 vols. Denman's Midwifery, by Francis. 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Maygriere's Midwifery, 200 plates. Muller's Physiology. Maury's Dental Surgery. Makenzie on the Eye. Nuttall's Botany. Orfila on Poisons. Oliver's Physiology. Pancoast's Surgery, 4to. plates. Pancoast's Wistar's Anatomy, 2 vols. Puerperal Fever, by Meigs and others. Parker on Stomach and Syphilis. Phrenology, Combe's. Phrenology, Spurzheim's. Phrenology, Calvert's. Pocket Anatomist. Pott's Surgery, 2 vols. Philip on the Vital Functions. Philip on Indigestion. Paris's Pharmacologia. Parr's Medical Dictionary, 2 vols. Paris's Medical Chemistry. J. G. AUNER'S CATALOGUE. Paine's Commentaries, 2 vols. Paris on Diet. Pemberton on the Viscera. Pott on Hydrocele. Physician's Vade Mecum. Physician's Case Book. Parke's Chemical Catechism. Phillips' Mineralogy. Paxten's Anatomy, 2 vols. Phillips on Diseases. Parson's Anatomical Preparations. Parrish's Surgical Observations. Parmly on the Teeth. Pritchard on Insanity. Plumbe on the Skin. Pereira's Materia Medica, 2 vols. Pereira on Dietetics. 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Smith's Anatomical Atlas. Surgeon's Dentist's Manual. Syme's Surgery. Snell on the Teeth. Sarlandiere's Anatomical Plates. Stokes on the Chest. Spurzhteim on the Brain. Scoutetten on Club-Foot. Smith on the Arteries. Smith's Minor Surgery. Stewart on Club-Foot. Spurzheim on Insanity. Tweedie's Lib. Prac. Medicine, 3 vols, Trimmer's Geology and Mineralogy. Thompson on Liver and Spleen. Thacher's Practice. Teale on Neuralgia. Trail's Medical Jurisprudence. Thacher's Dispensatory. Thacher on Hydrophobia. Trotter on Drunkenness. Timbrel on Ruptures. Travers on the Eye. Thomas's Practice. Thompson on Varioloid. Trousseau and Belloc on the Voice. Turner's Chemistry. Thomas's Domestic Medicine. Thornton's Botany. Trotter on Nervous Temperament. Thompson on Inflammation. Tavernier's Operative Surgery. Tweedie on Fever. Todd's Index Rerum. Tuson's Dissector's Guide. Ure's Chemical Dictionary, 2 vols. Underwood on Diseases of Children. United States Pharmacopoeia. Velpeau on the Breast. Vought on Bowel Complaints. Velpeau's Anatomy, 2 vols. Wood and Bache's Dispensatory. Wilson's Anatomist's Vade Mecum. Warrington's Obstetric Catechism. Warrington's Nurse's Guide. Walker on Beauty. Walker on Pathology, Willis on Urinary Diseases. Williams' Principles of Medicine. Williams on the Chest. Webster's Brande's Chemistry. Willan on the Skin. Winslow's Anatomy. Wilson on Febrile Diseases. Wilson on Spotted Fever. Williams on the Lungs. Williams' Catechism of Medical^Jutis prudence. ;-v / Walker on Woman. V Walker on Intermarriage. i Warren on Tumour. - Webster on Pestilence. Wilson's Dissector, by Goddard. Watson's Practice. Walshe on Cancer. Wilson on Electricity. Wilson on the Skin. Walshe on the Lungs. w* NLM010012431